JP2006251400A - Image forming method and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method suppressing generation of image blurring or filming for a long period of time and also preventing the flaw on the surface of a photoreceptor. <P>SOLUTION: The image forming method includes: a charging step of charging a latent image carrier, a latent image forming step forming a latent image; a developing step of forming a toner image; a transfer step of transferring the toner image to a transferred material; and a cleaning step of cleaning toner remaining on the surface of the latent image carrier after the transference using a conductive brush abutting against the surface of the latent image carrier and used in the state in which a voltage is applied thereto. A cleaning means includes the first and second conductive brushes disposed along the rotational direction of the latent image carrier. The polarity of the voltage applied to the first conductive brush is reversed to that of the voltage applied to the second conductive brush. The toner includes composite particles in which inorganic particulate is dispersed in resin particles. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming method and an image forming apparatus using electrophotography.

  Conventionally, an image is formed by electrophotography, in which the surface of a latent image carrier is charged and exposed to develop an electrostatic latent image produced with colored toner to produce a toner image, and the toner image is transferred to a transfer paper or the like. This is performed by fixing this with a heat roll or the like to form an image. Untransferred toner, discharge products generated by the charging process, and the like remain on the surface of the latent image carrier (hereinafter sometimes referred to as “photosensitive member”) after the transfer process. Therefore, a cleaning process for removing these residues prior to the next image forming process is required. As a means for cleaning the photosensitive member, a blade cleaning method using an elastic cleaning blade or a brush cleaning method using a magnetic brush or a fur brush is used.

  Of these, the method of bringing the rubber blade into contact with the photosensitive member is the most widely used because of its simplicity. However, with the cleaning blade method, due to the mechanical friction between the blade and the photoreceptor, when the organic photoreceptor is used, the wear of the photoreceptor is likely to proceed, and the life of the photoreceptor cannot be significantly extended. However, the high-speed machine used in the above has a drawback that the cleaning blade tip is worn and chipped, so that the cleaning reliability cannot be maintained for a long time.

  On the other hand, in recent years, there has been a demand for higher image quality in this type of image forming apparatus, and as a means for this, toner by a polymerization method has been used. The toner produced by the polymerization method can be remarkably reduced in particle size, narrowed in particle size distribution, and spheroidized, and can improve dot reproducibility, developability, and transferability. On the other hand, when the blade cleaning method is used, a toner having a small particle size and a nearly spherical shape requires a higher blade pressing pressure for toner removal than the conventional irregularly pulverized toner, and the durability of the cleaning blade In addition, there is a problem that scratches on the photoconductor deteriorate.

  In contrast to the blade cleaning method, a brush cleaning method using a conductive brush such as a fur brush (see, for example, Patent Documents 1 to 4) has little deterioration in cleaning maintenance. In high-speed machines, the brush cleaning method is blade cleaning. It is advantageous to the system. Further, since brush cleaning is a cleaning method that positively uses an electric field, it has an advantage over spherical toner cleaning that was difficult with the blade method.

However, these fur brush cleaning methods have a lower mechanical scraping force on the surface of the photoreceptor than the blade cleaning method, and image blurring (image flow) occurs due to insufficient removal of discharge products generated from the charger. Cheap. The cause is considered as follows.
When the photosensitive member is charged by a charging means such as a corona charger or a conductive roller, it is known that discharge products such as ozone and NOx are generated in this process. Those ozone and NOx adhering to the surface of the photoconductor are combined with moisture in the atmosphere to reduce the electrical resistance of the surface of the photoconductor, making it difficult to hold the charge on the photoconductor, and it is assumed that image blurring occurs. In particular, in a high-speed machine, a high current value has to be set in order to charge the photoconductor, and a large amount of discharge products tend to adhere to the surface of the photoconductor, which is considered to accelerate the image blurring phenomenon.
Similarly, since the brush cleaning method is less scraping than the blade method, there is a problem that filming of an external additive such as silica as a developer component is likely to occur. Further, it has been found that when the shape of the toner is spherical, the toner interposed between the brush and the photoconductor rolls, so that the rubbing force between the photoconductor and the brush decreases, and further, image blur and filming deteriorate. .

  To reduce the rubbing force, the rubbing property can be improved by increasing the rigidity of the brush fibers and increasing the scraping property. In this case, however, the brush tip tends to repeatedly scratch like a record needle, and the scratch becomes deeper than in the case of the cleaning blade. As a result, the image quality such as streak density unevenness is significantly reduced. It will be.

In order to extend the life of the photoconductor, various photoconductors with improved wear resistance can be used for these problems, and such photoconductors have been proposed by the present applicant, for example. An example is a photoreceptor using a resin having a structural unit having a charge transporting ability and having a crosslinked structure (see Patent Document 5). Since these photoconductors are overwhelmingly superior in heat resistance and mechanical strength to conventional ones, deterioration due to photoconductor scratches and wear can be remarkably reduced, and the life of the photoconductor can be extended.
However, if these photoconductors with high wear resistance are applied to brush cleaning, scratches and wear are greatly improved, but discharge products adhering to the photoconductor surface cannot be scraped off. On the contrary, it has been found that simply increasing the rigidity of the brush and increasing the rubbing force does not improve it.

Various studies have been made to suppress the influence of discharge products and the like on these photoconductors with high wear resistance.
For example, in the case of using a photoconductor with high wear resistance, a method of heating the photoconductor with a heater or the like has been proposed in order to suppress image blur due to moisture absorption of a discharge product attached to the surface of the photoconductor. (For example, see Patent Documents 6 to 7). In this case, it is possible to remove moisture absorbed by heating the photosensitive member with a heater or the like, and to effectively prevent the image flow.

  However, this method increases the power consumption required by the image forming apparatus, and requires an arrangement of a heater inside the photosensitive member and a power supply mechanism for the heater, resulting in complicated apparatus and high cost. The problem remains. In addition, since it is a technology that removes only moisture that has absorbed moisture, rather than removing the discharge product itself, cumulative adhesion of the discharge product to the surface of the photoreceptor cannot be prevented. Does not provide a sufficient effect.

In addition, it has been proposed that a polishing unit having a function of polishing the photoconductor is disposed on the downstream side of the fur brush (the side where the charging unit is provided with respect to the fur brush) in the rotation direction of the photoconductor. (For example, refer patent document 8 etc.).
However, in this method, although the removability of discharge products and external additives is improved, it is difficult to adjust the surface of the photoreceptor uniformly. In addition, in the case of an organic photoreceptor whose surface layer is an organic layer, even if the photoreceptor has excellent wear resistance, the surface of the photoreceptor tends to be damaged or wear is accelerated. Image quality defects due to scratches are likely to occur.

In addition, as a fur brush, it has been proposed to use a fur brush using a fiber containing an anion exchangeable intercalation compound (see Patent Document 9).
However, in this method, the fur brush fibers are easily contaminated with the toner component, and the brush fibers are not likely to come into direct contact with the photosensitive member. Since it is determined by the surface area, it is difficult for the fur brush to fully perform its original function.

On the other hand, in order to prevent the occurrence of image spots or the like by suppressing the scattering of the toner and to obtain an excellent image quality, the particle diameter obtained by fixing inorganic fine particles having a number average primary particle diameter of 5 to 100 nm on the surface of the organic particles There has been proposed a cleanerless type image forming apparatus using toner containing composite particles having a particle size of 0.1 to 5.0 μm and provided with non-contact developing type developing means (see Patent Document 10).
However, in cleanerless systems that do not have blades, including cleanerless type image forming apparatuses that use toner with externally added composite particles as described above, the removal of discharge products from the surface of the photoreceptor is fundamental. Therefore, image blurring that occurs under high humidity becomes a problem.
JP 58-1111078 A JP-A-5-27651 JP-A-9-114339 JP 2002-258709 A JP 2000-241998 A Japanese Patent No. 3264218 JP 2002-91269 A JP 2004-117419 A JP 2001-312084 A JP 2002-62681 A

  An object of the present invention is to solve the above problems. That is, an object of the present invention is to provide an image forming method and an image forming apparatus using the image forming method that can suppress the occurrence of image blurring and filming over a long period of time and can also prevent scratches on the surface of the photoreceptor.

The above-mentioned subject is achieved by the following present invention. That is, the present invention
<1>
A charging step for charging the surface of the latent image carrier that can rotate in one direction, a latent image forming step for forming a latent image by irradiating the charged surface of the latent image carrier, and a developer containing toner. The latent image is developed on the surface of the latent image carrier after the toner image is transferred to the transfer body, the development step of developing the latent image to form a toner image, the transfer step of transferring the toner image to the transfer body. And a cleaning step in which the toner is cleaned by a cleaning means provided with a conductive brush that is in contact with the surface of the latent image carrier and is applied with a voltage.
The cleaning means includes a first conductive brush and a second conductive brush arranged along the rotation direction of the latent image carrier, and the polarity of the voltage applied to the first conductive brush And the polarity of the voltage applied to the second conductive brush is opposite,
In the image forming method, the toner includes composite particles in which inorganic fine particles are dispersed and contained in resin particles.

<2>
The image forming method according to <1>, wherein the composite particles have a volume average particle diameter in a range of 0.05 to 2 μm.

<3>
The number average particle diameter of the composite particles is taken as d _50, in the particle size distribution of the composite particles,
The ratio of the number of particles having a particle size of (1/2) × d ₅₀ or less with respect to the total number of particles, and the ratio of the number of particles having a particle size of (3/2) × d ₅₀ or more with respect to the total number of particles, respectively. <20> The image forming method according to <1>, wherein the number is 20% by number or less.

<4>
The image forming method according to <1>, wherein the inorganic fine particles are dispersed in the vicinity of the surface of the composite particle so as to form a convex portion on the surface of the composite particle.

<5>
The image forming method according to <1>, wherein the composite particles include a resin containing a nitrogen element.

<6>
The image forming method according to <1>, wherein the resin containing a nitrogen atom is a melamine resin.

<7>
The image forming method according to <1>, wherein a shape factor SF of the toner defined by the following formula (1) is in a range of 100 to 140.
Formula (1) SF = 100 × π × ML ² / 4A
[In the formula (1), SF represents the shape factor of the toner, ML represents the absolute maximum length of the toner particles, and A represents the projected area of the toner particles. ]

<8>
<1> The image forming method according to <1>, wherein the outermost surface layer of the latent image carrier contains a resin having a structural unit having a charge transporting ability and a crosslinked structure.

<9>
A structure in which the resin having a structural unit having a charge transporting ability and having a crosslinked structure has at least one charge transporting ability selected from a hydroxyl group, a carboxyl group, an alkoxysilyl group, an epoxy group, a thiol group, and an amino group. The image forming method according to claim 8, wherein the image forming method is a phenol-based resin or a siloxane-based resin containing units.

<10>
A latent image carrier that is rotatable in one direction; a charging unit that charges the surface of the latent image carrier; and a latent image forming unit that forms a latent image by irradiating the charged surface of the latent image carrier with light. A developer containing toner is supplied to the surface of the latent image carrier on which the latent image is formed, thereby developing the latent image to form a toner image; and transferring the toner image to the transfer target And a transfer means that contacts the surface of the latent image carrier and is used in a state where a voltage is applied, and after the toner image is transferred to the transfer target by the conductive brush Cleaning means for cleaning the toner remaining on the surface of the latent image carrier,
An image in which the charging unit, the latent image forming unit, the developing unit, the transfer unit, and the cleaning unit are arranged in this order around the latent image carrier along the rotation direction of the latent image carrier. In the forming device,
The cleaning means includes a first conductive brush and a second conductive brush arranged along the rotation direction of the latent image carrier, and the polarity of the voltage applied to the first conductive brush And the polarity of the voltage applied to the second conductive brush is opposite,
In the image forming apparatus, the toner includes composite particles in which inorganic fine particles are dispersed and contained in resin particles.

  As described above, according to the present invention, it is possible to provide an image forming method and an image forming apparatus using the image forming method capable of suppressing the occurrence of image blur and filming over a long period of time and also suppressing the scratches on the surface of the photoreceptor. Can do.

  The image forming method of the present invention comprises a charging step for charging the surface of a latent image carrier that can be rotated in one direction (hereinafter sometimes referred to as a “photosensitive member”), and a surface of the charged latent image carrier. A latent image forming step of forming a latent image by irradiating light; a developing step of developing the latent image with a developer containing toner to form a toner image; and a transferring step of transferring the toner image to a transfer object. The conductive brush used in a state in which the toner remaining on the surface of the latent image carrier after the toner image is transferred to the transfer target is in contact with the surface of the latent image carrier and a voltage is applied. A first cleaning brush and a second conductive brush disposed along the rotational direction of the latent image carrier. Including and before The polarity of the voltage applied to the first conductive brush is opposite to the polarity of the voltage applied to the second conductive brush, and the toner contains inorganic fine particles dispersed in the resin particles. It is characterized by containing composite particles.

The cleaning means used in the image forming method of the present invention includes a first conductive brush and a second conductive brush arranged along the rotation direction of the latent image carrier. The voltage applied to the first conductive brush and the voltage applied to the second conductive brush are selected so that their polarities are reversed.
The reason for using such a cleaning means is as follows. That is, the polarity of the toner (residual toner) remaining on the surface of the photoconductor after the transfer process is finished is not limited to the residual toner having the same polarity as the normal polarity of the toner supplied to the surface of the photoconductor during development. This is because there is always residual toner of reverse polarity. This is due to the influence of the electric field applied to the toner at the time of transfer, and although the proportion of the total toner is small, the polarity of a part of the residual toner is reversed opposite to the normal polarity of the toner supplied to the surface of the photoreceptor during development ( This is because the polarity is reversed. Therefore, it is inevitable that toners having both positive and negative polarities are mixed in the residual toner.

Therefore, if only one conductive brush is used for the cleaning means, or even if there are two or more conductive brushes, any one of the conductive brushes is applied with a voltage of one polarity, the surface of the photoreceptor Of the residual toner adhering to the toner, the toner having one of the polarities cannot be substantially removed, resulting in deterioration of image quality.
By using the cleaning means as described above, there is less rubbing between the photoconductor and the conductive brush compared to the cleaning blade method, so there is less damage and wear on the surface of the photoconductor even in image formation over a long period of time. Residual toner that contains both positive and negative charged particles can be efficiently cleaned, but the discharge products adhering to the surface of the photoconductor that cause image blurring and deposits due to filming can be removed sufficiently. Can not.

  However, in the present invention, toner is used because it contains (externally added) composite particles (hereinafter, may be abbreviated as “composite particles”) in which inorganic fine particles are dispersed and contained in resin particles. The composite particles exhibit an effect of polishing and removing the discharge product and the like adhering to the surface of the photoreceptor stably over a long period of time. For this reason, generation | occurrence | production of an image blur can be suppressed over a long period of time also in a high humidity environment. This is presumably because the inorganic fine particles existing in the vicinity of the surface of the composite particle stably exhibit and maintain the polishing effect of the discharge product or the like attached to the surface of the photoreceptor for a long period of time.

In addition, since the composite particle used for the technique disclosed in Patent Document 10 also has inorganic fine particles, it is considered that the effects described above can be expected.
However, the composite particles are particles in which inorganic fine particles are fixed to the surface. Therefore, when viewed over time, due to stress such as agitation in the developing machine, the inorganic fine particles fixed on the surface fall off, or the inorganic fine particles exist so as to largely protrude from the resin particle main body. Therefore, it is considered that the pressing force concentrates on the inorganic fine particles and is buried inside the resin particles. That is, in such a case, it is considered that the polishing effect by the inorganic fine particles fixed on the surface is lowered with time even if the polishing effect is sufficiently exhibited in the initial stage. For this reason, there is a risk that the polishing effect is too strong in the initial stage and may damage the surface of the photoreceptor, and over time, the polishing effect becomes too low and the discharge products may not be sufficiently removed. it is conceivable that.

  In contrast, in the composite particles used in the present invention, since the inorganic fine particles are firmly fixed to the resin matrix in the resin particles, the inorganic fine particles present in the vicinity of the surface fall off or from the resin particle surface to the inside. And will not be buried. Therefore, the polishing effect is stably maintained over a long period.

On the other hand, discharge products and the like adhering to the surface of the photoreceptor can be removed by adding an abrasive to the toner. However, since the abrasive is a particle made of 100% inorganic material, if the surface of the photoconductor is not high in strength, the polishing effect is too strong and the polishing becomes uneven and causes scratches on the surface of the photoconductor. .
In contrast, the composite particles used in the present invention serve as a cushion in which the resin matrix surrounding the inorganic fine particles existing in the vicinity of the surface that exhibits the polishing effect appropriately disperses and absorbs the pressure applied to the inorganic fine particles. In addition, the surface of the inorganic fine particles not held by the resin matrix is covered with a thin resin layer, etc., and the polishing effect sufficient to remove discharge products and the like while suppressing the generation of scratches on the surface of the photoreceptor. It can be secured.

  In particular, toner produced by a polymerization method that achieves high image quality tends to be nearly spherical. Since these polymerized toners are spherical, rolling between the conductive brush and the photosensitive member is likely to occur, so that the force for rubbing the photosensitive member is low, and further, compared with conventional pulverized toner that is indefinite, discharge products, etc. There is a tendency that the removability of is reduced. Even in the case of these spherical toners, a sufficient discharge product removal effect can be obtained by adding the composite particles used in the present invention to the toner.

Note that the polarity of the voltage applied to the first conductive brush and the second conductive brush arranged along the rotation direction of the photosensitive member is not particularly limited as long as one is opposite to the other. . However, in order to enhance the removal efficiency of residual toner and the effect of suppressing filming and image blur, (1) a conductive brush on the upstream side in the rotation direction of the photosensitive member (hereinafter referred to as “first conductive brush”) (2) a conductive brush on the downstream side in the rotation direction of the photosensitive member (hereinafter sometimes referred to as a “second conductive brush”). It is preferable to use composite particles that apply a voltage having the same polarity as the normal polarity of the toner and (3) are charged to a polarity opposite to the normal polarity of the toner.
For example, if the normal polarity of the toner is negative, the voltage applied to the first conductive brush is positive, the voltage applied to the second conductive brush is negative, and the charged state of the composite particles is positive. The reason why such a combination is suitable is not necessarily clear, but the present inventors speculate as follows.

  This is because, after the transfer, the surface of the photoconductor is sequentially cleaned by the first conductive brush and the second conductive brush, so that the first polarity to which the polarity opposite to the normal polarity of the toner is first applied. The majority of the residual toner (that is, residual toner having the same polarity as the normal polarity of the toner) is cleaned by the conductive brush, and the first conductive brush is cleaned by the second conductive brush having the same polarity as the normal polarity of the toner. By collecting a small amount of residual toner (that is, residual toner having a polarity opposite to the normal polarity of the toner) that has not been completely cleaned, residual toner can be efficiently recovered.

  On the other hand, in the case of brush cleaning, if the toner that also functions as a spacer material between the brush fiber and the photoconductor is extremely insufficient, the frictional heat to the photoconductor by the conductive brush increases, and the conductive brush deteriorates. Filming may occur due to rubbing of the external additive. Such a state is likely to occur in the case described above.

However, since the composite particles have a charge opposite in polarity to the regular charge of the toner, they are not easily transferred to the transfer target side in the transfer process, and the contact portion (first contact between the first conductive brush and the photosensitive member). To the cleaning section). Furthermore, since the voltage applied to the first conductive brush and the polarity of the composite particles are the same polarity, the composite particles are difficult to be collected by the first conductive brush, and most of the composite particles are the second particles. The toner is supplied to a contact portion (second cleaning portion) between the conductive brush and the photosensitive member.
For this reason, the composite particles supplied to the contact portion between the second conductive brush and the photosensitive member compensate for the shortage of residual toner that functions as a spacer material between the second conductive brush and the photosensitive member. , Suppress the occurrence of filming. In addition, the composite particles sufficiently exhibit the effect of polishing and removing discharge products and the like not only in the first cleaning portion but also in the second cleaning portion due to the mechanical rubbing force between the photoreceptor and the conductive brush. Therefore, image blurring and filming can be prevented more reliably.

-Composite particles-
Next, the composite particles used in the present invention will be described in more detail.
In the present invention, the composite particles are particles in which inorganic fine particles are dispersed and contained in the resin particles as described above. The dispersion state of the inorganic fine particles is not particularly limited, but it is necessary that at least some of the inorganic fine particles are dispersed so as to be located in the vicinity of the composite particle surface.

Furthermore, in order to ensure a sufficient polishing ability, it is particularly preferable that the inorganic fine particles dispersed in the vicinity of the composite particle surface have convex portions formed on the composite particle surface. When the inorganic fine particles are not dispersed in such a state, the inorganic fine particles existing in the vicinity of the composite particle surface cannot sufficiently exhibit the polishing ability, and image blur may occur.
“Forming convex portions” means a state in which the presence of convex shapes due to inorganic fine particles can be confirmed on the surface of the composite particles when the composite particles are observed with an electron microscope or a transmission electron microscope. .

The volume average particle size of the composite particles is preferably in the range of 0.05 to 2.0 μm, more preferably in the range of 0.10 to 1.0 μm, and still more preferably in the range of 0.3 to 0.6 μm. is there.
If the volume average particle size is smaller than 0.05 μm, the effect of removing the deposits on the surface of the photoreceptor such as discharge products may be insufficient. On the other hand, if it is larger than 2.0 μm, the charge adjusting ability may be insufficient.

  The volume average particle size of the composite particles can be measured by, for example, a laser diffraction / scattering type particle size distribution measuring apparatus [Mastersizer 2000 (trade name) manufactured by Malvern, Inc.]. “Volume average particle size” is the particle size when the cumulative distribution reaches 50% when the cumulative distribution is drawn from the small diameter side to the particle size range (channel) divided based on the particle size distribution. Means diameter.

In order to prevent the composite particles externally added to the toner particles from falling off, the true specific gravity of the composite particles is preferably in the range of 1.3 to 2.0, and preferably in the range of 1.4 to 1.8. More preferably, it is within.
When the true specific gravity exceeds 2.0, the composite particles externally added to the toner particles may easily fall off from the toner particles. On the other hand, when the true specific gravity is less than 1.3, the composite particles may easily aggregate. In addition, since the composite particles used in the present invention have inorganic fine particles in the vicinity of the surface, compared with the case where only the resin particles are used alone, there are few contact points between the particles and it is difficult to form strong aggregation. There is a merit.

Moreover, it is desirable that the particle size distribution of the composite particles is controlled within a certain range. Specifically, when the number average particle diameter of the composite particles is d ₅₀ , in the particle size distribution of the composite particles, the ratio of the number of particles having a particle diameter of (1/2) × d ₅₀ or less with respect to the total number of particles (hereinafter, , And may be abbreviated as “small diameter side particle ratio”), and the ratio of the number of particles having a particle size of (3/2) × d ₅₀ or more with respect to the total number of particles (hereinafter abbreviated as “large diameter side particle ratio”). May be 20% by number or less, more preferably 15% by number or less, and still more preferably 10% by number or less.
When the ratio of the small-diameter side particles exceeds 20% by number, the smaller-diameter composite particles increase, so that the small-diameter composite particles adhere to the surface of the photoreceptor and the chargeability of the toner is also unstable. May end up. On the other hand, when the large-diameter side particle ratio exceeds 20% by number, the charge adjustment effect is reduced.
The number average particle diameter can be measured by, for example, a laser diffraction / scattering type particle size distribution measuring apparatus [Mastersizer 2000 (trade name) manufactured by Malvern, Inc.].

  The amount of the composite particles added to the toner particles to be described later is preferably in the range of 0.1 to 3.0% by weight, more preferably 0.2 to 1.0% by weight with respect to 100 parts by weight of the toner particles. is there. When the addition amount is less than 0.1% by weight, the image density after continuous image formation under high-temperature and high-humidity is formed when the toner added with composite particles is used after being stored under high-temperature and high-humidity. May get worse. On the other hand, when the addition amount is more than 3.0% by weight, the charge adjustment effect is reduced.

  Next, materials constituting the composite particles will be described. As resin which comprises composite particle | grains, it can select suitably from well-known various resin, such as a thermoplastic resin and a thermosetting resin. However, since the thermoplastic resin may not sufficiently increase the hardness of the composite particles as a whole, it is preferable to use a thermosetting resin. In order to give the composite particles a stable polishing effect over a long period of time, the composite particles do not deform even under stress such as stirring in a developing machine, and the inorganic fine particles exist in the vicinity of the composite particle surface. This is because it is necessary to prevent the burial of the earth.

  Specific examples of the thermoplastic resin include polyolefin resins such as polyethylene, polypropylene; polyvinyl and polyvinylidene resins such as polystyrene, acrylic resin, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride. , Polyvinyl carbazole, polyvinyl ether and polyvinyl ketone; vinyl chloride-vinyl acetate copolymer; styrene-acrylic acid copolymer; straight silicone resin composed of organosiloxane bond or a modified product thereof; fluororesin such as polytetrafluoroethylene, polyfluoride And vinyl chloride, polyvinylidene fluoride, polychlorotrifluoroethylene; polyester; polycarbonate and the like.

In producing composite particles using these resins, the hardness of the composite particles can be further increased by using a crosslinking component such as divinylbenzene together.
Examples of thermosetting resins include phenol resins; amino resins such as urea-formaldehyde resins, melamine resins, benzoguanamine resins, urea resins, polyamide resins; epoxy resins, and the like.

Among these resins, it is preferable to use a resin containing a nitrogen atom having an electron-donating ability, and among the resins containing a nitrogen atom, a melamine resin that is thermosetting and has a high electron-donating ability is used. Is preferred.
On the other hand, the inorganic fine particles are not particularly limited as long as they have a polishing ability for deposits such as discharge products on the surface of the photoreceptor. For example, the Mohs hardness is preferably in the range of 3 to 9, The diameter (primary particle diameter) is preferably in the range of 5 to 500 nm. Moreover, although it does not specifically limit as a shape, An indefinite shape, a spherical form, a cube, etc. are mentioned.
Examples of the inorganic fine particles include carbon black, silica, alumina, titania, zinc oxide, strontium titanate, cerium oxide, and calcium carbonate. For the purpose of adjusting the charge imparting ability, silica is used. It is preferable to use it.

In the image forming method of the present invention, the composite particles are charged to a polarity opposite to the normal polarity of the toner in order to increase the efficiency with which the composite particles are supplied to the cleaning unit without being transferred. It is preferable. However, it is not preferable that the toner has extremely strong chargeability because it causes charging deterioration of the toner itself.
For this purpose, a material having charging characteristics shifted to the opposite side of the normal polarity of the toner is selected as the resin component constituting the composite particle with respect to the normal polarity of the toner, and inorganic fine particles (inorganic As the material, it is preferable to select a material having charging characteristics shifted to the opposite side to the polarity of the resin component (that is, if the normal polarity of the toner is negative, for example, in terms of relative potential difference) The relationship of the relative potential difference between the toner charged to the normal polarity, the resin component, and the inorganic fine particles is “toner charged to the normal polarity <resin component> inorganic fine particles”).
In this case, the composite particles as a whole exhibit a function opposite to the normal charge of the toner while stabilizing the chargeability of the toner, and thus function efficiently as a cleaning aid.

The relationship between the normal polarity (minus) of the toner and the relative potential difference between the resin component and the inorganic fine particles as described above: “Toner <resin component> inorganic fine particles when charged to the normal polarity (minus)” As an example of a suitable combination of a resin component satisfying the above and inorganic fine particles, a combination of a melamine resin having a strong positive charge and a silica having a strong negative charge or a phenol resin having a strong positive charge and a strong Examples thereof include a combination of silica having negative chargeability, a combination of a phenol resin having strong positive chargeability and silica having strong negative chargeability.
Even when the normal polarity of the toner is positive, composite particles charged with the opposite polarity to the normal polarity of the toner can be obtained by appropriately selecting the resin component and the inorganic fine particles based on the above-described concept. it can.

  The composite particles used in the present invention are not particularly limited. For example, a method for producing a granular resin by using a polymerization method such as suspension polymerization, emulsion polymerization, suspension polymerization, monomer or oligomer as a poor solvent. A method of dispersing in and granulating by surface tension while carrying out a crosslinking reaction, a low molecular component and a crosslinking agent are mixed and reacted by melt kneading, etc., and then pulverized to a predetermined particle size by wind force and mechanical force In the production process of known resin particles such as a method, it can be obtained by mixing inorganic fine particles. For example, after dispersing inorganic fine particles in a solution containing at least a precursor of a resin component such as a monomer, composite particles can be obtained by polymerization or a crosslinking reaction.

  The uneven shape on the surface of the composite particles by the inorganic fine particles may be, for example, [1] adjusting the amount and particle size of the inorganic fine particles used, or [2] a precursor of the resin component (monomer in the liquid phase). Etc.) and inorganic fine particles are formed, and then the inorganic fine particles buried inside are exposed so as to form protrusions on the surface by utilizing the shrinkage caused by polymerization or crosslinking reaction of the aggregates, [3] After forming wet particles composed of resin components and inorganic fine particles, the inorganic fine particles embedded inside are exposed so as to form protrusions on the surface by utilizing the shrinkage of the resin matrix during drying. Or [4] After forming the core particles composed only of the resin component, it can be adjusted by forming a coating layer composed of the resin component and the inorganic fine particles.

Hereinafter, a composite particle made of silica fine particles and a melamine resin is taken as an example to describe in detail a production example of a composite particle used in the present invention. However, the production example of the composite particle of the present invention is not limited to this. Absent.
First, while suspending a solution containing colloidal silica having an average particle size of about several nanometers to several tens of nanometers, a melamine compound, and an aldehyde compound in an aqueous medium, the melamine compound and the aldehyde compound are reacted under basic conditions to form water. An aqueous solution containing an initial condensate of melamine resin that is soluble in water is prepared (step (a)).

Subsequently, by adding an acid catalyst to the aqueous solution obtained in the step (a), spherical composite particles in which silica fine particles are dispersed in the melamine resin are precipitated (step (b)).
Here, as a melamine compound used at the said (a) process, well-known things, such as a substituted melamine compound which substituted hydrogen of the amino group of melamine and the melamine with the alkyl group, the alkenyl group, and the phenyl group, can be used. Of these, inexpensive melamine is most preferred.

Examples of the aldehyde compound used in the step (a) include formaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde, furfural and the like, but formaldehyde and paraformaldehyde which are inexpensive and have good reactivity with the melamine compound are preferable.
Moreover, it is preferable to mix | blend an aldehyde compound so that it may become 1.1-6.0 mol per effective aldehyde group with respect to 1 mol of said melamine compounds, especially 1.2-4.0 mol.

  As the colloidal silica used in the step (a), those having an average particle diameter preferably in the range of 5 to 70 nm can be used. In addition, although powdered colloidal silica such as precipitated silica powder and vapor phase method silica powder can be used, it is preferable to use a colloidal silica sol stably dispersed to the primary particle level in the medium. .

  When the average particle diameter of colloidal silica exceeds 70 nm, the shape of the composite particles deposited in the step (b) may be difficult to be spherical. If it is less than 5 nm, it may be difficult to sharply control the particle size distribution of the composite particles. The S average particle size of the composite particles obtained through the step (b) is generally smaller as the melamine resin concentration is lower and the average particle size of the colloidal silica is smaller.

The amount of colloidal silica added is preferably in the range of 0.5 to 100 parts by weight and more preferably in the range of 1 to 50 parts by weight with respect to 100 parts by weight of the melamine compound. If the addition amount is less than 0.5 parts by weight, it may be difficult to obtain composite particles in step (b). Moreover, although composite particle | grains are obtained even if the addition amount exceeds 100 weight part, in this case, since it is a by-product of the minute and non-spherical aggregate particle | grains, it may be unpreferable.
As described above, the specific production process of the composite particle itself has been described by taking the composite particle composed of the silica fine particle and the melamine resin as an example. Next, regardless of the kind of the inorganic fine particle and the resin component, it can be used in the present invention. The matters common to all possible types of composite particles will be described.

First, the surface of the composite particles may be surface-treated with a coupling agent such as a silane coupling agent represented by the following general formula.
General formula (a) R ₁ Si (X) ₃
General formula (b) R ₁ R ₂ Si (X) ₂
· General formula _{(c) R 1 R 2 R} 3 SiX

In the above formulas, R ₁ represents an alkyl group having 1 to 20 carbon atoms or a perfluoroalkyl group, and R ₂ and R ₃ are each a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or perfluoro. An alkyl group or an aryl group is represented, and X represents a chlorine atom, an alkoxy group, an NCO group, or an acetoxy group.
By such surface treatment, it is possible to prevent the occurrence of comet and filming on the surface of the photosensitive member, and to improve the dispersibility and adhesion to the toner, as well as the charging stability and charge exchange property associated with the hydrophobicity control. Expect more.

Among these, those represented by the general formula (a) are preferable from the viewpoint of increasing the charge amount, and CH ₃ (CH ₂ ) nSi (OCH ₃ ) ₃ (where n = 5 to 19) is particularly preferable. For the same reason, R ₁ is preferably an alkyl group having 7 to 16 carbon atoms or a perfluoroalkyl group.
Such a treatment with a coupling agent is preferable, for example, in the case of a method in which the composite particles are immersed in a solution containing the coupling agent and dried, whereby a uniform coating can be formed. The adhesion amount of the coupling agent is preferably in the range of 0.1 to 25% by weight with respect to the composite particles.

Further, the surface of the composite particle itself may be treated with silicone oil or the like. A known silicone oil can be used for this treatment, and a dry method such as a spray drying method in which a treatment agent or a solution containing a treatment agent is sprayed on composite particles suspended in a gas phase, or a treatment agent is used. It can process using the wet method which immerses a composite particle in the solution to contain, and dries.
In the composite particles used in the present invention, the inorganic fine particles may be uniformly dispersed or non-uniformly dispersed, but as described above, the inorganic fine particles are always present near the surface of the composite particles. Need to be. In the case of non-uniform dispersion, the inorganic fine particles are preferably unevenly distributed in the vicinity of the surface of the composite particles in order to ensure a sufficient polishing effect.

Here, the above-mentioned “uneven distribution” includes a range (number) of 40 to 100% of the inorganic fine particles contained in the composite particles in a range of 10% from the surface to the depth direction with respect to the particle size direction of the composite particles. That means. Such an uneven distribution state can be adjusted by appropriately optimizing the production process of the composite particles. For example, according to the above-described method for producing composite particles composed of colloidal silica and a melamine resin, such uneven distribution is performed. The state can be obtained.
For the purpose of improving the fluidity or chargeability of the toner, known fine powders such as inorganic fine powders such as silica, organic fine powders such as fatty acids or their derivatives or metal salts, fine powders of fluororesins, etc., together with composite particles Can also be used together.

In addition, in order to control the fluidity and chargeability of the toner, it is necessary to sufficiently coat the surface of the toner particles, but the composite particles alone may not provide a sufficient coating. It is preferable to use an inorganic compound in combination as long as the effect of removing the product is not impaired. In particular, when using composite particles having a large particle size, it is preferable to use an inorganic compound having a small particle size in combination as long as the effect of removing discharge products by the composite particles is not impaired. As the inorganic compound having a small particle size, an inorganic compound having a volume average particle size of 80 nm or less is preferable, and an inorganic compound having a particle size of 300 nm or less is more preferable.
As the inorganic compound having a small particle diameter, known compounds can be used, and examples thereof include silica, alumina, titania, calcium carbonate, magnesium carbonate, calcium phosphate, cerium oxide and the like. Further, a known surface treatment may be applied to the surface of these inorganic fine particles depending on the purpose.

  The addition amount of such an inorganic compound having a small particle diameter is preferably 0.3 to 3 parts by weight, and more preferably 0.5 to 2 parts by weight with respect to 100 parts by weight of the toner particles. If the addition amount is less than 0.3 parts by weight, the toner fluidity may not be sufficiently obtained, and blocking suppression due to thermal storage may be insufficient. On the other hand, when the addition amount is more than 3 parts by weight, an excessive covering state is caused, and the excessive inorganic oxide may be transferred to the contact member to cause a secondary failure.

The composite particles are added to the toner particles and mixed. The mixing can be performed by a known mixer such as a V-type blender, a Henschel mixer, or a Redige mixer. At this time, various additives may be added as necessary.
Examples of these additives include other fluidizing agents, cleaning aids such as polystyrene fine particles, polymethyl methacrylate fine particles, and polyvinylidene fluoride fine particles, or transfer aids.

In addition, the external addition method to the toner may be the external addition of the composite particles alone, the simultaneous addition and mixing of the composite particles and other external additives, or the other external addition after the composite particles are added and mixed first. Even if the additive is added and mixed, the composite particles may be added and mixed after the other external additive is added and mixed first.
However, when composite particles and other external additives are used in combination, the toner and composite particles are first mixed, and a weaker shear (shearing force) is applied and other inorganic oxide fine powder is added. By doing so, the effect of preventing the occurrence of image blur can be exhibited more significantly even in a high humidity environment. Moreover, it does not matter even if it goes through a sieving process after external addition mixing.

-Toner (and developer)-
Next, the toner used in the present invention will be described. The toner used in the image forming method of the present invention is not particularly limited by the production method. For example, a binder resin, a colorant, a release agent, and a charge control agent as necessary are kneaded, pulverized, and classified. A kneading and pulverizing method; a method of changing the shape of particles obtained by the kneading and pulverizing method by mechanical impact force or thermal energy; a dispersion formed by emulsion polymerization of a polymerizable monomer of a binder resin; Is mixed with a colorant, a release agent, and a dispersion of a charge control agent, if necessary, and agglomerated and heat-fused to obtain toner particles; polymerization for obtaining a binder resin; Suspension polymerization method in which a solution of a chargeable monomer, a colorant, a release agent, and a charge control agent, if necessary, is suspended in an aqueous solvent for polymerization; a binder resin, a colorant, a release agent, necessary Depending on the solution, it can be obtained by a suspension method in which a solution such as a charge control agent is suspended in an aqueous solvent and granulated. It shall can be used.

  In addition, known methods such as a production method in which the toner obtained by the above method is used as a core and a coating layer is further formed to have a core-shell structure can be used, but from the viewpoint of shape control and particle size distribution control, an aqueous solvent Suspension polymerization method, emulsion polymerization aggregation method and dissolution suspension method produced by the above method are preferred, and emulsion polymerization aggregation method is particularly preferred.

The toner particles include a binder resin and a colorant, and a release agent, silica, a charge control agent, or the like may be used as necessary. The volume average particle diameter is preferably in the range of 2 to 12 μm, and more preferably in the range of 3 to 9 μm.
Further, the shape factor SF of the toner is preferably in the range of 100 to 140, more preferably 125 to 140, from the viewpoint of obtaining high development, transferability, and high image quality. In particular, by setting the shape factor SF within the range of 125 to 140, even when a contact-type charging member is used, adhesion of the toner and external additives to the charging member can be further suppressed.
Here, the toner shape factor SF means a value represented by the following expression (1).
Formula (1) SF = 100 × π × ML ² / 4A
In Equation (1), SF represents the shape factor of the toner, ML represents the absolute maximum length of the toner particles, and A represents the projected area of the toner particles.

  The absolute maximum length of the toner particles represented by formula (1) and the projected area of the toner were obtained by photographing a toner particle image magnified 500 times using an optical microscope (Nikon, Microphoto-FXA). For example, the image information can be obtained by introducing the image information into an image analysis apparatus (Luzex III) manufactured by Nicole through an interface and performing image analysis. The value of the shape factor SF1 can be obtained as an average value based on data obtained by measuring 1000 toner particles sampled randomly.

  Binder resins used include styrenes such as styrene and chlorostyrene; monoolefins such as ethylene, propylene, butylene, and isoprene; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate, and vinyl butyrate; Α-methylene aliphatic monocarboxylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate Examples of vinyl polymers such as vinyl methyl ether, vinyl ethyl ether, vinyl butyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, vinyl isopropenyl ketone; Particularly typical binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene- Mention may be made of maleic anhydride copolymers, polyethylene, polypropylene and the like. Further examples include polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin wax and the like.

  In addition, toner colorants include magnetic powders such as magnetite and ferrite, carbon black, aniline blue, caryl blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, and malachite green oxa. Rate, lamp black, rose bengal, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 17, C.I. I. Pigment blue 15: 1, C.I. I. Pigment Blue 15: 3 can be exemplified as a representative one.

Typical examples of the release agent include low molecular polyethylene, low molecular polypropylene, Fischer-Tropsch wax, montan wax, carnauba wax, rice wax, and candelilla wax.
Further, a charge control agent may be added to the toner as necessary. Known charge control agents can be used, but azo metal complex compounds, metal complex compounds of salicylic acid, and resin type charge control agents containing polar groups can be used. When the toner is manufactured by a wet manufacturing method, it is preferable to use a material that is difficult to dissolve in water in terms of controlling ionic strength and reducing wastewater contamination. The toner used in the present invention may be either a magnetic toner containing a magnetic material or a non-magnetic toner containing no magnetic material.

As the inorganic oxide that can be added to the toner, a small-diameter inorganic oxide having a primary particle size of 40 nm or less is used for powder flowability, charge control, and the like. Mention may be made of large-diameter inorganic oxides. Although these inorganic oxide fine particles can use a well-known thing, the following things can be illustrated.
For example, silica, alumina, titania, zirconia, barium titanate, aluminum titanate, strontium titanate, magnesium titanate, zinc oxide, chromium oxide, cerium oxide, antimony oxide, tungsten oxide, tin oxide, tellurium oxide, manganese oxide, Various inorganic oxides such as boron oxide, silicon carbide, boron carbide, titanium carbide, silicon nitride, titanium nitride, boron nitride, calcium carbonate, calcium carbonate, magnesium carbonate and calcium phosphate, nitrides, borides and the like are suitable. used.

  Further, titanium coupling agents such as tetrabutyl titanate, tetraoctyl titanate, isopropyl triisostearoyl titanate, isopropyl tridecylbenzenesulfonyl titanate, bis (dioctyl pyrophosphate) oxyacetate titanate, γ- (2-amino) Ethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl) γ-aminopropyltrimethoxysilane Hydrochloride, hexamethyldisilazane, methyltrimethoxysilane, butyltrimethoxysilane, isobutyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxy The treatment may be performed with a silane coupling agent such as silane, decyltrimethoxysilane, dodecyltrimethoxysilane, phenyltrimethoxysilane, o-methylphenyltrimethoxysilane, and p-methylphenyltrimethoxysilane. Further, hydrophobic treatment with a higher fatty acid metal salt such as silicone oil, aluminum stearate, zinc stearate, calcium stearate can be preferably performed.

The addition of the external additive such as the inorganic fine particles described above can be performed by mixing the toner particles and the external additive with a Henschel mixer or a V blender. In addition, when the toner particles are produced by a wet method, external addition can be performed by a wet method.
In addition, when the toner used in the present invention is a color toner, it is preferably used by mixing with a carrier. As the carrier, a known carrier can be used, and for example, iron powder, glass beads, ferrite powder, nickel powder, or those having a resin coating on the surface thereof are used. Further, the mixing ratio of the carrier and the toner can be set as appropriate.

-Image forming device-
Next, the image forming apparatus of the present invention using the image forming method of the present invention will be described. The image forming apparatus of the present invention forms an image using the image forming method of the present invention. Specifically, the latent image carrier that can rotate in one direction and the surface of the latent image carrier are provided. A charging means for charging; a latent image forming means for forming a latent image by irradiating light onto the surface of the charged latent image carrier; and a latent image carrier surface on which the latent image is formed with a developer containing toner. A developing unit that develops the latent image to form a toner image, a transfer unit that transfers the toner image to a transfer target, a surface that contacts the surface of the latent image carrier, and a voltage is A conductive brush used in an applied state, and cleaning means for cleaning toner remaining on the surface of the latent image carrier after the toner image is transferred to the transfer target by the conductive brush. , The charging unit, the latent image forming unit, and the development Stage, the transfer unit, and the cleaning means has a deployed configuration around the latent image bearing member along a rotational direction of the latent image bearing member in this order. Here, as the cleaning unit, the above-described cleaning unit is used, and as the toner, a toner containing the above-described composite particles is used.
As the charging unit, the latent image forming unit, the developing unit, and the transfer unit, known units can be used, and other known units (for example, an intermediate transfer member) may be used as necessary.

The image forming apparatus of the present invention will be specifically described below with reference to the drawings.
FIG. 1 is a schematic diagram showing an example of an image forming apparatus of the present invention. In FIG. 1, 1 is a photosensitive member, 2 is a charging device (non-contact charger), 3 is an exposure device, 4 is a developing device, 5 is a transfer device, 7 is a cleaning device, 40 is an image forming device, 41 (41a to 41d) is an image forming unit, 47 is a belt conveying device, 48 is a conveying belt, 49, 50, 51, 52, 53, 54 are A tension roll, 55 is a suction roll, 56 is a fixing roll, 57 is a storage tray, 58 is a tension roll, 59 is a belt cleaner, and 60 is a recording material supply device.

The main configuration of the image forming apparatus 40 shown in FIG. 1 includes a belt conveyance device 47 including a conveyance belt 40 and the like, and each color sequentially arranged along the rotation direction of the conveyance belt 40. It consists of four image forming units 41a, 41b, 41c and 41d that form toner images. Each of the image forming units 41a, 41b, 41c, and 41d can form, for example, yellow, cyan, magenta, and black toner images.
The image forming unit 41 includes the charging device 2, the exposure device 3, the developing device 4, the transfer device 5, and the photosensitive member 1, arranged around the photosensitive member 1 in the following order along the rotation direction thereof. The roll-shaped transfer device 5, which includes the cleaning device 7, is disposed so as to face the photoreceptor 1 via the transport belt 40.

The belt conveying device 47 includes a conveying belt 48 and stretching rolls 49, 50, 51, arranged on the inner peripheral surface of the conveying belt 48 in the following order along the rotation direction of the conveying belt 48 in order to stretch the conveying belt 48. 52, 53, 54, an adsorbing roll 55 disposed opposite to the tension roll 49 and the conveying belt 48, a tension roll 58 disposed on the outer peripheral surface of the conveying belt 48, and a belt cleaner 59.
The tension rolls 50, 51, 52, and 53 are linearly arranged so as to be parallel to the four image forming units 41a, 41b, 41c, and 41d, and the tension rolls 50 are arranged in parallel to each other. , 51, 52, 53 and the image forming units 41a, 41b, 41c, 41d, a tension roll 49 is disposed on the paper feed side and a tension roll 50 is disposed on the paper discharge side.

  On the inner peripheral surface side of the conveyor belt 48 between the tension rolls 49 and 50, a transfer device 5 is disposed so as to face the photoreceptor 1 of each image forming unit. The tension roll 58 is disposed so as to press the outer peripheral surface side of the conveyor belt 48 between the tension rolls 52 and 53 in order to adjust the tension of the conveyor belt 48, and the belt cleaner 59 is It is arranged on the outer peripheral surface side of the conveyor belt 48 between the tension rolls 53 and 54.

In addition, a recording material supply device 60 that supplies a recording medium to a contact portion (transfer portion) between the four photosensitive members 1 and the conveyance belt 48 is provided on the side of the tension roll 49 on which the tension roll 50 is provided. The recording medium is disposed on the opposite side, and at the time of image formation, the recording medium is supplied from the recording material supply device 60 to the transfer portion through the contact portion between the suction roll 55 and the conveying belt 48 at a predetermined timing.
On the other hand, a pair of fixing rolls 56 and a receiving tray 57 are arranged on the opposite side of the tension roll 50 from the side where the tension roll 49 is provided. The paper is discharged to the storage tray 57 through the contact portions of the pair of fixing rolls 56.

  The color image is formed in the image forming apparatus 40 as follows. First, the recording medium is supplied from the recording material supply device 60 to the four transfer portions through the contact portion between the suction roll 55 and the conveyance belt 48. Here, the toner images of the respective colors formed by the respective image forming units 41a, 41b, 41c, and 41d are sequentially superimposed so as to coincide with the original document image information when the recording medium passes through the transfer portion. Transcribed. Subsequently, the recording medium onto which the four color toner images are transferred is conveyed to the contact portion of the pair of fixing rolls 56, and the toner image is heat-pressed when passing through the contact portion. As a result, the toner image is fixed on the surface of the recording medium and is discharged as it is to the storage tray 57. The transport belt 48 after the recording medium is transported and transferred is cleaned by a belt cleaner 59 to prepare for the next image formation.

Next, details of the image forming unit 41 used in the image forming apparatus 40 will be described.
FIG. 2 is a schematic diagram showing an example of an image forming unit used in the image forming apparatus of the present invention, and specifically shows an enlarged view of the image forming unit 41 shown in FIG. In FIG. 2, the same members as those in FIG. The image forming unit shown in FIG. 2 can be used in addition to the image forming apparatus shown in FIG. 1, and can be applied to an apparatus using an intermediate transfer belt instead of the conveying belt 48, for example. Further, as shown in FIG. 3, an image forming unit in which the charging device 2 is replaced with a contact-type charging device 8 such as a charging roll may be used.

The toner image is formed and transferred in the image forming unit shown in FIG. 2 as follows.
First, along with the rotation of the photosensitive member 1, the surface of the photosensitive member 1 is charged by the charging device, and then, the surface of the charged photosensitive member 1 is irradiated with light corresponding to the document image information by the exposure device 3. A latent image is formed. Subsequently, a developer containing toner is supplied from the developing device to the surface of the photoreceptor 1 on which the latent image is formed, whereby the latent image is developed and a toner image is formed. This toner image is transferred to the surface of a recording medium (not shown in FIG. 2) conveyed to the contact portion (transfer portion) between the photosensitive member 1 and the conveyance belt 48. In this transfer, a voltage having a polarity opposite to the normal polarity of the toner is applied to the roll-shaped transfer device 5. Subsequently, the surface of the photoconductor 1 after the transfer is completed is cleaned by the cleaning device 7 to remove deposits such as toner remaining on the surface, and prepares for the next image formation.

-Cleaning means (cleaning device)-
Next, the cleaning means used in the present invention will be described. As described above, the cleaning means used in the present invention includes the first conductive brush and the second conductive brush arranged along the rotation direction of the latent image carrier. A voltage is applied to the first conductive brush and the second conductive brush so that the polarities are opposite to each other.
The first conductive brush and the second conductive brush are usually used in one pair (two), but two or more each may be used. For example, in the order of the first conductive brush, the second conductive brush, the first conductive brush, the second conductive brush, the first conductive brush, Four may be sufficient as it arrange | positioned in order of 1 conductive brush, 2nd conductive brush, and 2nd conductive brush.
Further, if at least one of the first conductive brush and at least one of the second conductive brush are provided, the number of the first conductive brush and the number of the second conductive brush are not the same. Also good.

  In the following description, it is assumed that the first conductive brush and the second conductive brush are used in a pair (two), and the first conductive brush located on the upstream side in the photoconductor rotation direction is the first. The conductive brush located on the downstream side in the photoconductor rotation direction will be described as a second conductive brush.

FIG. 4 is a schematic diagram showing an example of the cleaning device used in the present invention, and is an enlarged view of the cleaning device 7 shown in FIG. 2 (or FIG. 3). The cleaning device 7 shown in FIG. 4 is of a cartridge type and includes two cleaning units.
That is, in FIG. 4, a housing 700 includes a first cleaning unit including a roll-shaped brush member (first conductive brush) 701a, a recovery roll member 702a, and a scraper 703a, and a roll-shaped brush member (second brush). A conductive brush) 701b, a recovery roll member 702b, and a second cleaning unit including a scraper 703b are accommodated. Instead of the collecting roll members 702a and 702b, a flicking member that mechanically knocks off the toner adhering to the roll brush member may be installed.

The side close to the photoreceptor 1 of the housing 700 is open, and the outer peripheral surfaces (surfaces formed by the brush tips) of the roll-shaped brush members 701 a and 701 b are in contact with the outer peripheral surface of the photoreceptor 1 at the openings. Yes.
The roll-shaped brush member 701a (or 701b) is formed in a roll shape by arranging a plurality of fibers on the outer peripheral surface of the shaft 705a (or 705b) from the center to the outer peripheral surface. The shafts 705a and 705b are arranged in parallel to the tangent to the photoreceptor 1, and the roll-shaped brush members 701a and 701b are rotatable about the shafts 705a and 705b. Further, the distance between each of the shafts 705a and 705b and the photoreceptor 1 is such that the amount of biting into the photoreceptor 1 at the brush tip of the roll-shaped brush members 701a and 701b is a predetermined value (preferably 0.5 to 2.0 mm). Preferably, it is set to be 0.9 to 1.8 mm.

Examples of the fibers of the roll-shaped brush members 701a and 701b include resin fibers such as nylon, acrylic, polyolefin, and polyester. Commercial products such as these can be used. The thickness of these fibers is preferably 30 denier or less, more preferably 20 denier or less, and still more preferably 0.5 to 10 denier. The fiber density is preferably 20,000 fibers / inch ² or more, more preferably 60,000 fibers / inch ² or more.

  The recovery roll members 702a and 702b are obtained by curing a thermosetting resin and molding it into a roll shape and arranging it on the outer periphery of the shafts 705a and 705b. The outer peripheral surface of the collection roll member 702a (or 702b) is in contact with the brush tip of the roll brush member 701a (or 701b). The shaft 705a (or 705b) is disposed in parallel to the shaft 704a (or 704b), and the recovery roll member 702a (or 702b) can rotate about the shaft 705a (or 705b) as a rotation axis.

  Examples of the thermosetting resin used for the collection roll members 702a and 702b include phenol resin, urea resin, melamine resin, unsaturated polyester, epoxy resin, and polyimide resin. Among them, the phenol resin is preferable because it has advantages such as high dimensional accuracy, easy molding, excellent surface smoothness of the molded body, and low cost.

  The bending elastic modulus of the collection roll members 702a and 702b is preferably 700 kPa or more. When the flexural modulus is less than 700 kPa, the collection roll member is bent, and it is difficult to maintain the contact position and the amount of biting with the brush member or the blade member at a predetermined value. In addition, if a material having a flexural modulus of less than 700 kPa is used to increase the thickness of the collecting roll member to maintain rigidity, molding shrinkage increases, resulting in insufficient dimensional accuracy, and further increases the weight. Costs increase due to problems such as an increase in molding time and the need for subsequent processes. In addition, a bending elastic modulus here says the value measured based on JISK7203.

Further, since the collection roll members 702a and 702b are in contact with the roll brush members 701a and 701b and the scrapers 703a and 703b, respectively, the outer peripheral surfaces of the collection roll members 702a and 702b can be worn by the operation.
In the present invention, when the amount of wear is measured in accordance with JIS K6902 on the outer peripheral surface of the recovery roll member, the amount of wear is preferably 20 mg or less. Thereby, the contact pressure and the amount of biting of the brush member and the blade member can be set to a large value, and even in that case, stable cleaning can be performed over a long period of time. In addition, when the amount of wear exceeds 20 mg, the life | cycle of a collection | recovery roll member may become inadequate and frequent replacement | exchange may be needed.

  Further, the Rockwell hardness (M scale) of the collection roll members 702a and 702b is preferably 100 or more. When the Rockwell hardness is 100 or more, molding with high dimensional accuracy is possible, and the roll member is extremely strong against scraping. Here, the Rockwell hardness is a value measured according to JIS K7202.

The scrapers 703a and 703b are made of a thin metal plate, and are arranged so that an edge portion at one end thereof is in contact with the outer peripheral surface of the recovery roll members 702a and 702b. The other ends of the scrapers 703a and 703b are each fixed to the housing 700, but the fixing method thereof is not particularly limited, and may be fixed by using a mounting bracket 706 as in the scraper 703b. You may fix to 700 directly.
The material of the scrapers 703a and 703b is preferably stainless steel or phosphor bronze from the viewpoint of high durability and low cost. The thickness of the scrapers 703a and 703b is preferably 0.02 to 2 mm, more preferably 0.05 to 1 mm. A blade member may be used instead of the scraper.

In the cleaning device 7 having the above configuration, first, residual toner remaining on the photoreceptor 1 after the transfer is removed by the roll-shaped brush members 701a and 701b. Next, the residual toner is transferred to the contact position with the collection roll members 702a and 702b by the rotation of the roll brush members 701a and 701b and collected. As a result, the brush tips of the roll-shaped brush members 701 a and 701 b are regenerated and repeatedly used for cleaning the photoreceptor 1.
Residual toner adhering to the collection roll members 702a and 702b is transferred to a contact position with the scrapers 703a and 703b by the rotation of the collection roll members 702a and 702b, and is removed by the scrapers 703a and 703b. Thereby, the surface of the collection | recovery roll members 702a and 702b is also reproduced | regenerated and it is repeatedly used for reproduction | regeneration of the brush front-end | tip of a roll-shaped brush member.

In the present invention, voltages having different polarities are applied to both of the roll-shaped brush members 701a and 701b in order to electrostatically remove adhering substances such as toner and paper dust on the photoreceptor 1. However, it is preferable that a mechanism for applying a cleaning bias having a potential difference between the roll-shaped brush member 701a (or 701b) and the recovery roll member 702a (or 702b) is preferable.
More specifically, by applying a predetermined voltage to the roll-shaped brush member 701a (or 701b), the residual toner on the photoreceptor 1 is attached to the roll-shaped brush member 701a (or 701b) by the electrostatic attraction force. Can be made. The roll-shaped brush member 701a (or 701b) is applied to the collection roll member 702a (or 702b) by applying a voltage having an absolute value larger than that of the voltage applied to the roll-shaped brush member 701a (or 701b) and the same polarity. The residual toner attached to the toner can be attached to the collecting roll member 702a (or 702b). The potential difference (absolute value) between the roll brush member and the collection roll member is preferably 100 V or higher, more preferably 200 V or higher, and further preferably 650 V.

In order to apply a voltage to the roll brush members 701a and 701b, it is necessary that the fibers of the brush member have conductivity. Here, as a method for imparting conductivity to the fibers of the brush member, a method of blending conductive powder or an ionic conductive material into the fibers, a method of forming a conductive layer inside or outside the fibers, and the like can be mentioned. Moreover, the resistance value of the fiber to which conductivity is imparted is preferably 10 ² to 10 ¹¹ Ω · cm for a single fiber.
Examples of a method for adjusting the electrical resistance of the collection roll members 702a and 702b include a method of filling an inorganic filler and / or an organic filler. When the collection roll member is filled with an inorganic filler or an organic filler, there is an advantage that the rigidity of the collection roll member is increased.

  Examples of the inorganic filler include metal powders such as tin, iron, copper, and aluminum, metal fibers, and glass fibers. Organic fillers include carbon black, carbon powder, graphite, magnetic powder, metal oxides such as zinc oxide, tin oxide and titanium oxide, metal sulfides such as copper sulfide and zinc sulfide, so-called hard such as strontium, barium and rare earth. Ferrite such as ferrite, magnetite, copper, zinc, nickel and manganese, or those whose surfaces are subjected to conductive treatment as necessary, copper, iron, manganese, nickel, zinc, cobalt, barium, aluminum, tin, lithium, magnesium, Metal oxide solid solutions obtained by firing at high temperatures selected from oxides, hydroxides, carbonates or metal compounds containing different metal elements such as silicon and phosphorus, so-called composite metal oxides, and polyanilines Can be mentioned.

The resistance value when a voltage of 500 V is applied to the collection roll members 702a and 702b is preferably 1 × 10 ⁵ to 1 × 10 ¹⁰ Ω · cm, more preferably 1 × 10 ⁶ to 1 × 10 ⁸ Ω · cm. is there. When the resistance value is less than 1 × 10 ⁵ Ω, electric charge is injected into the collecting roll member, and the polarity of fine powder such as toner and paper powder scraped off by the brush member is reversed. May be difficult. On the other hand, if the resistance value of the collecting roll member exceeds 1 × 10 ¹⁰ Ω · cm, a phenomenon in which charges are accumulated in the collecting roll member (charge up) is likely to occur. In some cases, it may be difficult to electrically adsorb.

Note that the cleaning device shown in FIG. 4 includes two cleaning units each including a roll brush member, a recovery roll member, and a blade member. In use, the polarity of the voltage applied to both roll brush members Are adjusted to be opposite to each other.
If the number of cleaning units is only one, sufficient cleaning performance cannot be obtained. Therefore, in the present invention, it is necessary to provide a pair of cleaning units as described above. Other cleaning units may be provided.

Note that the polarity of the residual toner remaining on the photoreceptor 1 after transfer is likely to vary due to the influence of the transfer electric field. That is, most of the residual toner exists in the same polarity as the polarity of the toner supplied to the photoreceptor 1 during development, but a part of the residual toner may be reversed to the opposite polarity.
In such a case, it is applied to the roll brush member of the cleaning unit composed of the roll brush member 701a, the recovery roll member 702a, and the scraper 703a, and the cleaning unit composed of the roll brush member 701b, the recovery roll member 702b, and the scraper 703b. By using different voltages for cleaning one of the remaining toner charged to the normal polarity, and the other for cleaning the remaining toner charged to the opposite polarity, the remaining charged charged to the normal polarity. Both the toner and the residual toner charged to the opposite polarity can be efficiently removed.
More specifically, first, in the first cleaning unit, a voltage having a polarity different from the normal polarity of the toner is applied to the roll-shaped brush member 701a and the recovery roll member 702a, and the normal toner occupying most of the residual toner. Polar toner is electrostatically adsorbed and removed. Next, in the second cleaning unit, by applying a voltage having the same polarity as the polarity of the toner stacker to the roll brush member 701b and the recovery roll member 702b, the residual toner charged to the opposite polarity is electrostatically removed. It is effective to remove by adsorption.

-Photoconductor-
Next, the photoreceptor used in the present invention will be described. As the photosensitive member used in the present invention, a known photosensitive member can be used. For example, it is preferable to use a photosensitive member having the following layer structure.
FIG. 4 is a schematic cross-sectional view showing an example of a photoreceptor used in the image forming apparatus of the present invention. 1 is a photoreceptor, 11 is a conductive substrate, 12 is an undercoat layer, 13 is a charge generation layer, and 14 is The charge transport layer, 15 represents a protective layer, and 16 represents a photosensitive layer.
The photoreceptor 1 is obtained by laminating an undercoat layer 12, a charge generation layer 13, a charge transport layer 14, and a protective layer 15 in this order on the surface of a conductive substrate 11, and the charge generation layer 13, the charge transport layer 14 and the protective layer 15 are protected. The layer 15 constitutes the photosensitive layer 16. When the photosensitive member has a laminated structure as shown in FIG. 3, it is preferable that the protective layer 15 contains a resin having a crosslinked structure. Moreover, you may abbreviate | omit the protective layer 15 as needed.

Next, details of each layer of the photoreceptor shown in FIG. 4 will be described.
Examples of conductive substrates include metal plates, metal drums, metal belts, or conductive polymers using metals or alloys such as aluminum, copper, zinc, stainless steel, chromium, nickel, molybdenum, vanadium, indium, gold, platinum, etc. In addition, a paper, a plastic film, a belt, or the like coated, vapor-deposited, or laminated with a conductive compound such as indium oxide or a metal or alloy such as aluminum, palladium, or gold. When the photosensitive drum is used in a laser printer, the laser oscillation wavelength is preferably from 350 nm to 850 nm, and the shorter wavelength is preferable because the resolution is excellent.

  In order to prevent interference fringes generated when laser light is irradiated, the surface of the support is preferably roughened to a center line average roughness Ra of 0.04 μm to 0.5 μm. If Ra is smaller than 0.04 μm, it becomes close to a mirror surface, so that the effect of preventing interference cannot be obtained. If Ra is larger than 0.5 μm, the image quality may be coarse. When non-interfering light is used for the light source, it is not particularly necessary to roughen the interference fringes, and it is possible to prevent the occurrence of defects due to the unevenness of the surface of the base material, which is suitable for longer life.

As a roughening method, wet honing is performed by suspending an abrasive in water and spraying on the support, or centerless grinding in which the support is pressed against a rotating grindstone to perform continuous grinding, an anode Oxidation and the like are preferred.
The anodizing treatment is to form an oxide film on the aluminum surface by anodizing in an electrolyte solution using aluminum as an anode. Examples of the electrolyte solution include a sulfuric acid solution and an oxalic acid solution. However, the intact porous anodic oxide film is chemically active, easily contaminated, and has a large resistance fluctuation due to the environment. Therefore, the pores in the anodized film are sealed with pressurized water vapor or boiling water (a metal salt such as nickel may be added) by volume expansion due to a hydration reaction, and a sealing process is performed to change to a more stable hydrated oxide. .

The thickness of the anodic oxide film is preferably 0.3 to 15 μm. When it is thinner than 0.3 μm, the barrier property against injection is poor and the effect is not sufficient. On the other hand, if it is thicker than 15 μm, the residual potential increases due to repeated use.
The treatment with an acidic treatment solution comprising phosphoric acid, chromic acid and hydrofluoric acid is carried out as follows. The mixing ratio of phosphoric acid, chromic acid and hydrofluoric acid in the acidic treatment liquid is such that phosphoric acid is in the range of 10 to 11% by weight, chromic acid is in the range of 3 to 5% by weight, and hydrofluoric acid is in the range of 0.5 to 2% by weight. The total concentration of these acids is preferably in the range of 13.5 to 18% by weight. The processing temperature is 42 to 48 ° C., but by keeping the processing temperature high, a thicker film can be formed faster. About the film thickness of a film, 0.3-15 micrometers is preferable. When it is thinner than 0.3 μm, the barrier property against injection is poor and the effect is not sufficient. On the other hand, if it is thicker than 15 μm, the residual potential increases due to repeated use.

  The anodizing treatment can be performed by immersing in pure water at 90 to 100 ° C. for 5 to 60 minutes or by contacting with heated steam at 90 to 120 ° C. for 5 to 60 minutes. About the film thickness of a film, 0.1-5 micrometers is preferable. This can be further anodized using an electrolyte solution with low film solubility such as adipic acid, boric acid, borate, phosphate, phthalate, maleate, benzoate, tartrate, citrate. Good.

  If desired, an intermediate layer can be formed between the conductive substrate and the photosensitive layer. Materials used include zirconium chelate compounds, zirconium alkoxide compounds, organic zirconium compounds such as zirconium coupling agents, titanium chelate compounds, titanium alkoxide compounds, organic titanium compounds such as titanate coupling agents, aluminum chelate compounds, aluminum coupling agents, etc. In addition to organic aluminum compounds, antimony alkoxide compounds, germanium alkoxide compounds, indium alkoxide compounds, indium chelate compounds, manganese alkoxide compounds, manganese chelate compounds, tin alkoxide compounds, tin chelate compounds, aluminum silicon alkoxide compounds, aluminum titanium alkoxide compounds, aluminum Zirconium alkoxide compounds, etc. Machine metal compounds, especially organic zirconium compound, an organic titanyl compound, an organic aluminum compound residual potential to show the good electrophotographic properties lower, are preferably used.

  Also, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris-2-methoxyethoxysilane, vinyltriacetoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-aminopropyl Triethoxysilane, γ-chloropropyltrimethoxysilane, γ-2-aminoethylaminopropyltrimethoxysilane, γ-mercapropropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, β-3,4-epoxycyclohexyltri It can be used by containing a silane coupling agent such as methoxysilane. Furthermore, polyvinyl alcohol, polyvinyl methyl ether, poly-N-vinyl imidazole, polyethylene oxide, ethyl cellulose, methyl cellulose, ethylene-acrylic acid copolymer, polyamide, polyimide, casein, gelatin, polyethylene, conventionally used for the undercoat layer Known binder resins such as polyester, phenol resin, vinyl chloride-vinyl acetate copolymer, epoxy resin, polyvinyl pyrrolidone, polyvinyl pyridine, polyurethane, polyglutamic acid, and polyacrylic acid can also be used.

These mixing ratios can be appropriately set as necessary. Further, an electron transporting pigment may be mixed / dispersed in the undercoat layer. Examples of the electron transport pigment include organic pigments such as perylene pigment, bisbenzimidazole perylene pigment, polycyclic quinone pigment, indigo pigment, and quinacridone pigment described in JP-A-47-30330, cyano group, nitro group, Examples thereof include organic pigments such as bisazo pigments and phthalocyanine pigments having electron-withdrawing substituents such as nitroso groups and halogen atoms, and inorganic pigments such as zinc oxide and titanium oxide. Among these pigments, perylene pigments, bisbenzimidazole perylene pigments and polycyclic quinone pigments, zinc oxide, and titanium oxide are preferably used because of their high electron mobility.
Further, the surface of these pigments may be surface-treated with the above-mentioned coupling agent or binder for the purpose of controlling dispersibility and charge transport property. If the amount of the electron transporting pigment is too large, the strength of the undercoat layer is lowered and a coating film defect is caused.

  As the mixing / dispersing method, a conventional method using a ball mill, a roll mill, a sand mill, an attritor, an ultrasonic wave, or the like is applied. Mixing / dispersing is carried out in an organic solvent, as long as the organic solvent dissolves a periodical metal compound or resin and does not cause gelation or aggregation when an electron transporting pigment is mixed / dispersed. Anything can be used. For example, methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene Ordinary organic solvents such as toluene can be used alone or in admixture of two or more.

  The thickness of the undercoat layer is generally 0.1 to 30 μm, preferably 0.2 to 25 μm. In addition, as the coating method used when the undercoat layer is provided, conventional methods such as a blade coating method, a Meyer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, and a curtain coating method are used. Can be used. The coated layer is dried to obtain an undercoat layer. Usually, the drying is performed at a temperature at which the solvent can be evaporated to form a film. In particular, the base material that has been subjected to the acidic solution treatment and the boehmite treatment is preferably formed with an intermediate layer because the defect concealing power of the base material tends to be insufficient.

Next, the charge generation layer will be described.
Charge generation materials include azo pigments such as bisazo and trisazo, condensed aromatic pigments such as dibromoanthanthrone, organic pigments such as perylene pigments, pyrrolopyrrole pigments, and phthalocyanine pigments, and inorganic pigments such as trigonal selenium and zinc oxide. Although all known ones can be used, inorganic pigments are particularly preferable when an exposure wavelength of 380 nm to 500 nm is used, and metal and metal-free phthalocyanine pigments are preferable when an exposure wavelength of 700 nm to 800 nm is used.

  Among these, hydroxygallium phthalocyanine disclosed in JP-A-5-263007 and JP-A-5-279591, chlorogallium phthalocyanine disclosed in JP-A-5-98181, JP-A-5-140472 and Particularly preferred are dichlorotin phthalocyanine disclosed in JP-A-5-140473, titanyl phthalocyanine disclosed in JP-A-4-189873 and JP-A-5-43813.

The binder resin used in combination with the charge generation material can be selected from a wide range of insulating resins, and organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, polyvinylpyrene, and polysilane. You can also choose from.
Preferred binder resins include polyvinyl butyral resin, polyarylate resin (polycondensate of bisphenol A and phthalic acid, etc.), polycarbonate resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyamide resin, acrylic resin. Insulating resin such as polyacrylamide resin, polyvinyl pyridine resin, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol resin, polyvinyl pyrrolidone resin can be used, but is not limited thereto. These binder resins can be used alone or in admixture of two or more.

The blending ratio between the charge generation material and the binder resin (weight ratio) is preferably in the range of 10: 1 to 1:10. In addition, as a method for dispersing them, a normal method such as a ball mill dispersion method, an attritor dispersion method, a sand mill dispersion method, or the like can be used. . Incidentally, it has been confirmed that the crystal form is not changed from that before dispersion in any of the dispersion methods implemented in the present invention.
Further, at the time of this dispersion, it is effective to make the particles have a particle size of 0.5 μm or less, preferably 0.3 μm or less, more preferably 0.15 μm or less. Moreover, as a solvent used for these dispersions, methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dioxane, tetrahydrofuran Ordinary organic solvents such as methylene chloride, chloroform, chlorobenzene and toluene can be used alone or in admixture of two or more.

  The thickness of the charge generation layer used in the present invention is generally 0.1 to 5 μm, preferably 0.2 to 2.0 μm. In addition, as a coating method used when the charge generation layer is provided, usual methods such as a blade coating method, a Meyer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, and a curtain coating method are used. Can be used.

Next, the charge transport layer will be described.
As the charge transport layer, a layer formed by a known technique can be used. These charge transport layers are formed using a charge transport material and a binder resin, or are formed using a polymer charge transport material.
Charge transport materials include quinone compounds such as p-benzoquinone, chloranil, bromanyl, anthraquinone, tetracyanoquinodimethane compounds, fluorenone compounds such as 2,4,7-trinitrofluorenone, xanthone compounds, benzophenone compounds , Electron transport compounds such as cyanovinyl compounds and ethylene compounds, triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted ethylene compounds, stilbene compounds, anthracene compounds, hydrazone compounds, etc. Examples thereof include pore-transporting compounds. These charge transport materials can be used alone or in combination of two or more, but are not limited thereto. These charge transport materials can be used alone or in combination of two or more, but from the viewpoint of mobility, those having structures shown by the following formulas (A) to (C) are preferable.

In the formula (A), R ¹⁴ represents a hydrogen atom or a methyl group. N means 1 or 2. Ar ₆ and Ar ₇ represent a substituted or unsubstituted aryl group, or —C (R ¹⁸ ) ═C (R ¹⁹ ) (R ²⁰ ), —CH═CH—CH═C (Ar) ₂ , As a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a substituted amino group substituted with an alkyl group having 1 to 3 carbon atoms. .
R ¹⁸ , R ¹⁹ and R ^{20 each} represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. Ar represents a substituted or unsubstituted aryl group.

In the formula (B), R ¹⁵ and R ¹⁵ ′ may be the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. R ¹⁶ , R ¹⁶ ′, R ¹⁷ and R ^{17 ′} may be the same or different and are a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or 1 to 2 carbon atoms. An amino group substituted with an alkyl group, a substituted or unsubstituted aryl group, or —C (R ¹⁸ ) ═C (R ¹⁹ ) (R ²⁰ ), —CH═CH—CH═C (Ar) ₂ Represent. m and n are integers of 0-2. R ¹⁸ , R ¹⁹ , R ²⁰ and Ar are the same as described in the formula (A).

In Formula (C), R ²¹ represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a substituted or unsubstituted aryl group, or —CH═CH—CH═C (Ar ) ₂ (Ar represents a substituted or unsubstituted aryl group). R ²² and R ²³ may be the same or different, and are an amino group substituted with a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an alkyl group having 1 to 2 carbon atoms. Represents a group or a substituted or unsubstituted aryl group.

  Further, the binder resin used for the charge transport layer is polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer, vinylidene chloride- Acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N- Vinyl carbazole, polysilane, and polymer charge transport materials such as polyester polymer charge transport materials disclosed in JP-A-8-176293 and JP-A-8-208820 can also be used. These binder resins can be used alone or in admixture of two or more. The blending ratio (weight ratio) between the charge transport material and the binder resin is preferably 10: 1 to 1: 5.

A polymer charge transport material can also be used alone. As the polymer charge transport material, known materials having charge transport properties such as poly-N-vinylcarbazole and polysilane can be used.
In particular, polyester polymer charge transport materials disclosed in JP-A-8-176293 and JP-A-8-208820 have a high charge transporting property and are particularly preferable. The polymer charge transport material alone can be used as the charge transport layer, but may be formed into a film by mixing with the binder resin.

The thickness of the charge transport layer used in the present invention is generally 5 to 50 μm, preferably 10 to 30 μm. As a coating method, a normal method such as a blade coating method, a Meyer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, or a curtain coating method can be used.
Furthermore, as a solvent used when providing a charge transport layer, aromatic hydrocarbons such as benzene, toluene, xylene and chlorobenzene, ketones such as acetone and 2-butanone, and halogenation such as methylene chloride, chloroform and ethylene chloride Ordinary organic solvents such as aliphatic hydrocarbons, cyclic ethers such as tetrahydrofuran and ethyl ether and linear ethers can be used alone or in admixture of two or more. Additives such as antioxidants, light stabilizers, and heat stabilizers are added to the photosensitive layer to prevent photoconductor deterioration due to ozone, oxidizing gas, or light or heat generated in the copying machine. can do.

For example, examples of the antioxidant include hindered phenol, hindered amine, paraphenylenediamine, arylalkane, hydroquinone, spirochroman, spiroidanone and derivatives thereof, organic sulfur compounds, and organic phosphorus compounds. Examples of the light stabilizer include derivatives such as benzophenone, benzotriazole, dithiocarbamate, and tetramethylpiperidine. In addition, at least one kind of electron accepting substance can be contained for the purpose of improving sensitivity, reducing residual potential, and reducing fatigue during repeated use.
Usable electron acceptors include, for example, succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrabromophthalic anhydride, tetracyanoethylene, tetracyanoquinodimethane, o-dinitrobenzene, m- Examples thereof include dinitrobenzene, chloranil, dinitroanthraquinone, trinitrofluorenone, picric acid, o-nitrobenzoic acid, p-nitrobenzoic acid, phthalic acid and the like, and compounds represented by general formula (I). Of these, benzene derivatives having electron-withdrawing substituents such as fluorenone, quinone and Cl, CN, NO ₂ are particularly preferred.

Next, the outermost surface layer (or protective layer) will be described.
Next, the surface portion (outermost surface layer; for example, the portion corresponding to the protective layer 15 in the case of the laminated structure shown in FIG. 4) of the photoreceptor used in the present invention includes a resin image having a crosslinked structure. It is preferable.
In the present invention, when the surface (outermost surface layer) of the latent image carrier contains a resin having a crosslinked structure, it is possible to increase the hardness of the surface of the photoreceptor and further improve the wear resistance. For this reason, even if image formation is performed for a longer period of time, scratches are generated on the surface or surface wear is suppressed, so that more uniform cleaning is possible. Hereinafter, description will be made on the assumption that the outermost surface layer is formed of a protective layer as shown in FIG.

As a material constituting the protective layer, it is preferable to use a resin having a crosslinked structure in order to improve wear resistance and ensure sufficient hardness. When such a material is not used, the surface hardness is low and sufficient wear resistance cannot be obtained, so that scratches and wear easily occur, and image formation can be performed for a longer period of time. It may not be possible.
In addition to the resin having a cross-linked structure, the protective layer may include a binder resin not having a cross-linked structure, conductive fine particles, a charge transporting material (compound having a charge transporting ability), and a fluororesin as necessary. Lubricating fine particles made of acrylic resin or acrylic resin may be included, and when forming the protective layer, a hard coating agent such as silicon or acrylic can be used as necessary. Although details of the method for forming the protective layer will be described later, a protective layer forming solution containing at least a precursor constituting a resin having a crosslinked structure is used for forming the protective layer.

  As the resin having a cross-linked structure, various materials can be used from the viewpoint of ensuring the hardness of the protective layer, but in terms of properties, mention may be made of phenolic resins, urethane resins, siloxane resins, epoxy resins, etc. Among these, siloxane resins and phenol resins are most preferable from the viewpoint of durability.

  Furthermore, from the viewpoint of electrical characteristics, image quality maintenance, and the like, the resin having a crosslinked structure preferably has charge transportability (including a structural unit having charge transportability). In this case, in the laminated structure type latent image carrier as shown in FIG. 4, the protective layer 15 can also function as a part of the charge transport layer 14.

  The resin having a structural unit having such a charge transporting ability and having a crosslinked structure is at least one charge transport selected from a hydroxyl group, a carboxyl group, an alkoxysilyl group, an epoxy group, a thiol group, and an amino group. More preferably, it is a phenol-based resin or a siloxane-based resin containing a conductive material (structural unit having charge transporting ability).

Examples of phenol derivatives used for the synthesis of phenolic resins include resorcin, bisphenol, substituted phenols containing one hydroxyl group such as phenol, cresol, xylenol, paraalkylphenol, paraphenylphenol, catechol, resorcinol, hydroquinone, etc. Compounds having a phenol structure such as substituted phenols containing two hydroxyl groups, bisphenols such as bisphenol A and bisphenol Z, and biphenols can be used, and generally those commercially available as raw materials for synthesizing phenol resins can be used.
In addition, as the phenol derivative, those containing a methylol group can be used, for example, monomers of monomethylolphenols, dimethylolphenols or trimethylolphenols, a mixture thereof, those obtained by oligomerization thereof, or those monomers and The mixture with an oligomer is mentioned.
In the present specification, a relatively large molecule having about 2 to 20 repeating molecular structural units is referred to as an oligomer, and a molecule smaller than that is referred to as a monomer.

  In addition, formaldehyde, paraformaldehyde, and the like can be used as aldehydes used in the synthesis of the phenolic resin. In synthesizing a phenolic resin, it can be obtained by reacting these raw materials in the presence of an acid catalyst or an alkali catalyst. However, commercially available phenolic resins can also be used.

As the acid catalyst, sulfuric acid, paratoluenesulfonic acid, phosphoric acid and the like are used. As the alkali catalyst, hydroxides or amine catalysts of alkali metals and alkaline earth metals such as NaOH, KOH, Ca (OH) ₂ and Ba (OH) ₂ are used.
Examples of the amine catalyst include, but are not limited to, ammonia, hexamethylenetetramine, trimethylamine, triethylamine, and triethanolamine.
When a basic catalyst is used, carriers may be significantly trapped by the remaining catalyst, which may deteriorate electrophotographic characteristics. For this reason, when a basic catalyst is used, after the reaction using the catalyst is completed, it must be neutralized with an acid, or deactivated or removed by contacting with an adsorbent such as silica gel, an ion exchange resin, or the like. Is preferred.
The phenolic resin having a crosslinked structure used in the present invention may be one obtained by further crosslinking a known phenolic resin as described above, and the phenolic resin itself has a crosslinked structure like a novolac type. You may have. In the former case, it is more preferable to use a resol type phenol resin.

The at least one charge transport material selected from a hydroxyl group, a carboxyl group, an alkoxysilyl group, an epoxy group, a thiol group, and an amino group is a compound represented by the following general formulas (I) to (VII). Is preferred. The charge transport material having a plurality of epoxy groups is preferably a compound represented by the following general formula (IV).
・ General formula (I)
_{^{F - [(X 1) m1}} - (R 1) m2 -Y] m3

In the general formula (I), F is an organic group derived from a compound having a hole transporting ability, X ¹ is an oxygen atom or a sulfur atom, R ¹ is an alkylene group (the number of carbon atoms is preferably 1 to 15, preferably 1 10 is more preferable), Y represents a hydroxyl group, a carboxyl group (—COOH), a thiol group (—SH) or an amino group (—NH ₂ ), m1 and m2 each independently represents 0 or 1, m3 represents An integer of 1 to 4 is shown.

・ General formula (II)
_{^{F - [(X 2) n1}} - (R 2) n2 - (Z) n3 G] n4
In the general formula (II), F represents an organic group derived from a compound having a hole transporting ability, X ² represents an oxygen atom or a sulfur atom, R ² represents an alkylene group (the number of carbon atoms is preferably 1 to 15, 1 to 10 is more preferable), Z is an alkylene group, oxygen atom, sulfur atom, NH or COO, G is an epoxy group, n1, n2 and n3 are each independently 0 or 1, n4 is 1 to 4 Indicates an integer.

・ General formula (III)
F- [D-Si (R ³ ) _(3-a) Q _a ] _b
In general formula (III), F represents an organic group derived from a compound having a hole transporting ability, D represents a divalent group having flexibility, R ³ represents a hydrogen atom, a substituted or unsubstituted alkyl group. (The carbon number is preferably 1-15, more preferably 1-10) or a substituted or unsubstituted aryl group (the carbon number is preferably 6-20, more preferably 6-15), Q is a hydrolyzable group. A represents an integer of 1 to 3, and b represents an integer of 1 to 4.

In addition, as the divalent group D having flexibility, specifically, a site of F for imparting photoelectric characteristics, a substituted silicon group contributing to the construction of a three-dimensional inorganic glassy network, It is a divalent group that plays a role in linking. In addition, D represents an organic group structure that imparts moderate flexibility to the portion of the inorganic glassy network that is hard but brittle, and plays a role of improving mechanical toughness as a film. Specific examples _{D, -CαH 2 α -, -} CβH 2 β -2 -, - CγH 2 γ -4 - 2 divalent hydrocarbon group (here represented by, alpha is an integer from 1 to 15 , Β represents an integer of 2 to 15, and γ represents an integer of 3 to 15), —COO—, —S—, —O—, —CH ₂ —C ₆ H ₄ —, —N═CH—, -(C ₆ H ₄ )-(C ₆ H ₄ )-and a characteristic group having a structure in which these characteristic groups are arbitrarily combined, and further, constituent atoms of these characteristic groups are substituted with other substituents And the like. The hydrolyzable group Q is preferably an alkoxy group, more preferably an alkoxy group having 1 to 15 carbon atoms.

・ General formula (IV)
_{^{F - [(X 4) n1}} - (R 4) n2 - (Z) n3 G] n4
In the general formula (IV), F represents an organic group derived from a compound having a hole transporting ability, X ⁴ represents an oxygen atom or a sulfur atom, R ⁴ represents an alkylene group (the number of carbon atoms is preferably 1 to 15, 1 to 10 is more preferable), Z is an alkylene group, oxygen atom, sulfur atom, NH or COO, G is an epoxy group, n1, n2 and n3 are each independently 0 or 1, n4 is 2 to 4 Indicates an integer.

・ General formula (V)
F-[(X ⁵ ) _n1 R ⁵ -ZH] _n2
Here, in the general formula (V), F represents an organic group derived from a compound having a hole transporting ability, X ⁵ represents an oxygen atom or a sulfur atom, R ⁵ represents an alkylene group, Z represents an oxygen atom, Sulfur atom, N or COO, n1 represents 0 or 1, and n2 represents an integer of 1 to 4. In general formula (V), ZH represents a hydroxyl group, a thiol group, an amino group, or a carboxyl group.

Here, in general formula (VI), F is an n7 valent organic group having hole transportability, T is a divalent group, Y is an oxygen atom or a sulfur atom, R ⁶ , R ⁷ and R ^8. Each independently represents a hydrogen atom or a monovalent organic group, R ⁹ represents a monovalent organic group, m1 represents 0 or 1, and n7 represents an integer of 1 to 4. However, R ⁸ and R ⁹ may be bonded to each other to form a heterocycle having Y as a heteroatom.

Here, in general formula (VII), F is an n8-valent organic group having hole transportability, T is a divalent group, R ¹⁰ is a monovalent organic group, m2 is 0 or 1, n8 represents an integer of 1 to 4, respectively.

  As the organic group F derived from the compound having a hole transporting ability in the compounds represented by the general formulas (I) to (VII), a compound represented by the following general formula (VIII) is preferable.

In general formula (VIII), Ar ^{1 to} Ar ⁴ each independently represents a substituted or unsubstituted aryl group, Ar ⁵ represents a substituted or unsubstituted aryl group or an arylene group, and k is 0 or 1.
Here, when k is 1, 1-4 of Ar ^{1 to} Ar ⁵ are-[(X ¹ ) _m1- (R ¹ ) in the compounds represented by the general formulas (I) to (VII). _{m2 -Y], - [(X} 2) n1 - (R 2) n2 - (Z) n3 G], - [D-Si (R 3) (3-a) Q a], - [(X 4) _{^{n1 - (R 4) n2 -}} (Z) n3 G] n4, - [(X 5) n1 R 5 -ZH] sites represented by _n2, the site which is bound to the organic group F in formula (VI) (Group shown in parentheses), or a bond that can be bonded to the site (group shown in parentheses) bonded to organic group F in general formula (VII), and k is 0 ¹ to ^{2 of} Ar ¹ , Ar ² , and Ar ⁵ are-[(X ¹ ) _m1- (R ¹ ) _m2 -Y] in the compounds represented by the general formulas (I) to (VII), _{^{- [(X 2) n1 -}} (R 2) n2 - (Z) n3 G], - [ _{^{-Si (R 3) (3-}} a) Q a], - [(X 4) n1 - (R 4) n2 - (Z) n3 G] n4, - [(X 5) n1 R 5 -ZH] n2 The site | part couple | bonded with the organic group F in general formula (VI) (group | base shown in a parenthesis), or the site | part couple | bonded with the organic group F in general formula (VII) (parenthesis) And a bond capable of bonding to the group shown in FIG.

In addition, conductive particles may be added to the protective layer in order to lower the residual potential. Examples of the conductive particles include metals, metal oxides, and carbon black. Among these, metals or metal oxides are more preferable.
Examples of the metal include aluminum, zinc, copper, chromium, nickel, silver, and stainless steel, or those obtained by depositing these metals on the surface of plastic particles.
Examples of the metal oxide include zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, tin-doped indium oxide, antimony and tantalum-doped tin oxide, and antimony-doped zirconium oxide. It is done.
These can be used alone or in combination of two or more. When two or more types are used in combination, they may be simply mixed, or may be in the form of a solid solution or fusion. From the viewpoint of transparency of the protective layer, the average particle size of the conductive particles is preferably 0.3 μm or less, and particularly preferably 0.1 μm or less.

In addition, a compound represented by the following general formula (IX-1) can also be added to the protective layer in order to control various physical properties such as the strength and film resistance of the protective layer.
General formula (IX-1) Si (R ³⁰ ) _(4-c) Q _c
In the above formula (IX-1), R ³⁰ represents a hydrogen atom, an alkyl group or a substituted or unsubstituted aryl group, Q represents a hydrolyzable group, and c represents an integer of 1 to 4.

Specific examples of the compound represented by the general formula (IX-1) include the following silane coupling agents.
That is, as the silane coupling agent, tetrafunctional alkoxysilanes such as tetramethoxysilane and tetraethoxysilane (c = 4); methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, methyltrimethoxyethoxysilane, vinyl Trimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltri Ethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, (tridecafluoro-1,1,2,2-tetrahydride Looctyl) triethoxysilane, (3,3,3-trifluoropropyl) trimethoxysilane, 3- (heptafluoroisopropoxy) propyltriethoxysilane, 1H, 1H, 2H, 2H-perfluoroalkyltriethoxysilane, 1H , 1H, 2H, 2H-perfluorodecyltriethoxysilane, trifunctional alkoxysilanes such as 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane (c = 3); dimethyldimethoxysilane, diphenyldimethoxysilane, methyl And bifunctional alkoxysilanes such as phenyldimethoxysilane (c = 2); monofunctional alkoxysilanes such as trimethylmethoxysilane (c = 1), and the like. Trifunctional and tetrafunctional alkoxysilanes are preferable for improving the strength of the film, and monofunctional and bifunctional alkoxysilanes are preferable for improving the flexibility and film formability.

  In addition, a silicon-based hard coat agent produced mainly from these coupling agents can also be used. Commercially available hard coat agents include KP-85, X-40-9740, X-40-2239 (manufactured by Shin-Etsu Silicone), and AY42-440, AY42-441, AY49-208 (manufactured by Toray Dow Corning). Etc.) can be used.

In order to increase the strength of the protective layer, it is also preferable to use a compound having two or more silicon atoms as shown in the general formula (IX-2).
・ General formula (IX-2)
B- (Si (R ³¹ ) _(3-d) Q _d ) ₂
In the above general formula (IX-2), B represents a divalent organic group, R ³¹ represents a hydrogen atom, an alkyl group or a substituted or unsubstituted aryl group, Q represents a hydrolyzable group, and d represents 1 to 3 Indicates an integer.

  Further, the protective layer has a cyclic compound having a repeating structural unit represented by the following general formula (IX-3) in order to extend pot life, control film characteristics, reduce torque, and improve the uniformity of the coating film surface, or Derivatives from the compounds can also be included.

In the above formula (IX-3), A ¹ and A ² each independently represent a monovalent organic group.
Examples of the cyclic compound having a repeating structural unit represented by the general formula (IX-3) include commercially available cyclic siloxanes. Specifically, cyclic dimethylcyclosiloxanes such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, 1,3,5-trimethyl-1,3,5- Triphenylcyclotrisiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetraphenylcyclotetrasiloxane, 1,3,5,7,9-pentamethyl-1,3,5,7 , 9-pentaphenylcyclopentasiloxane and other cyclic methylphenylcyclosiloxanes, hexaphenylcyclotrisiloxane and other cyclic phenylcyclosiloxanes, and 3- (3,3,3-trifluoropropyl) methylcyclotrisiloxane and other fluorine Atom-containing cyclosiloxanes, methylhydrosiloxa Mixture, pentamethylcyclopentasiloxane, mention may be made of phenyl hydrosilyl group-containing cyclosiloxanes of hydrocyclosiloxane like, cyclic siloxanes and vinyl group-containing cyclosiloxanes such as penta vinyl pentamethylcyclopentasiloxane like. These cyclic siloxane compounds may be used alone or in combination of two or more.

Furthermore, various fine particles can be added to the protective layer in order to control the contamination resistance adhesion, lubricity, hardness, etc. of the photoreceptor surface. They can be used alone or in combination of two or more.
Examples of the fine particles include silicon atom-containing fine particles. The silicon atom-containing fine particles are fine particles containing silicon as a constituent element, and specific examples include colloidal silica and silicone fine particles.

The colloidal silica used as the silicon atom-containing fine particles preferably has an average particle diameter of 1 to 100 nm, more preferably 10 to 30 nm, in an acidic or alkaline aqueous dispersion, or an organic solvent such as alcohol, ketone or ester. What was chosen from what was disperse | distributed and generally marketed can be used.
The solid content of colloidal silica in the protective layer is not particularly limited, but is preferably 0.1 to 50 weight based on the total solid content of the protective layer in terms of film formability, electrical characteristics, and strength. %, More preferably in the range of 0.1 to 30% by weight.

  Silicon fine particles used as silicon atom-containing fine particles are spherical and preferably have an average particle diameter of 1 to 500 nm, more preferably 10 to 100 nm, and are selected from silicone resin particles, silicone rubber particles and silicone surface-treated silica particles, A commercially available product can be used.

  Silicone fine particles are small particles that are chemically inert and excellent in dispersibility in resins, and because the content required to obtain sufficient properties is low, photosensitivity can be achieved without inhibiting the crosslinking reaction. The surface properties of the body can be improved. That is, it is possible to improve the lubricity and water repellency of the surface of the photoreceptor while being uniformly incorporated into a strong cross-linked structure, and maintain good wear resistance and contamination resistance adhesion over a long period of time. The content of the silicone fine particles in the protective layer is preferably in the range of 0.1 to 30% by weight, more preferably in the range of 0.5 to 10% by weight, based on the total solid content of the protective layer.

Other fine particles include fluorine-based fine particles such as ethylene tetrafluoride, trifluoride ethylene, propylene hexafluoride, vinyl fluoride, vinylidene fluoride, and the 8th Polymer Material Forum Lecture Proceedings p89. Fine particles made of a resin obtained by copolymerizing a fluororesin and a monomer having a hydroxyl group, ZnO—Al ₂ O ₃ , SnO ₂ —Sb ₂ O ₃ , In ₂ O ₃ —SnO ₂ , ZnO—TiO ₂ , ZnO Examples thereof include semiconductive metal oxides such as —TiO ₂ , MgO—Al ₂ O ₃ , FeO—TiO ₂ , TiO ₂ , SnO ₂ , In ₂ O ₃ , ZnO, and MgO. For the same purpose, an oil such as silicone oil can be added.

  Examples of the silicone oil include silicone oils such as dimethylpolysiloxane, diphenylpolysiloxane, and phenylmethylsiloxane, amino-modified polysiloxane, epoxy-modified polysiloxane, carboxyl-modified polysiloxane, carbinol-modified polysiloxane, methacryl-modified polysiloxane, and mercapto. Examples include reactive silicone oils such as modified polysiloxanes and phenol-modified polysiloxanes. These may be added in advance to the protective layer-forming coating solution, or may be impregnated under reduced pressure or increased pressure after producing the photoreceptor.

In addition, additives such as plasticizers, surface modifiers, antioxidants, and photodegradation inhibitors can also be used.
Examples of the plasticizer include biphenyl, biphenyl chloride, terphenyl, dibutyl phthalate, diethylene glycol phthalate, dioctyl phthalate, triphenyl phosphate, methyl naphthalene, benzophenone, chlorinated paraffin, polypropylene, polystyrene, and various fluorohydrocarbons. An antioxidant having a hindered phenol, hindered amine, thioether or phosphite partial structure can be added to the protective layer, which is effective in improving the potential stability and image quality when the environment changes.

  Examples of the antioxidant include the following compounds. For example, hindered phenols include “Sumilizer BHT-R”, “Sumilizer MDP-S”, “Sumilizer BBM-S”, “Sumizer WX-R”, “Sumizer NW”, “Sumizer BP-76”, “ Sumilizer BP-101 "," Sumilizer GA-80 "," Sumilizer GM "," Sumilizer GS "or more manufactured by Sumitomo Chemical Co., Ltd.," IRGANOX1010 "," IRGANOX1035 "," IRGANOX1076 "," IRGANOX1098 "," IRGANOX1098 "," 114 " ”,“ IRGANOX1222 ”,“ IRGANOX1330 ”,“ IRGANOX1425WL ”,“ IRGANOX1 20L "," IRGANOX 245 "," IRGANOX 259 "," IRGANOX 3114 "," IRGANOX 3790 "," IRGANOX 5057 "," IRGANOX 565 "or more, manufactured by Ciba Specialty Chemicals," ADK STAB AO-20 "," ADK STAB AO-30 "," ADEKA STAB " "AO-40", "ADK STAB AO-50", "ADK STAB AO-60", "ADK STAB AO-70", "ADK STAB AO-80", "ADK STAB AO-330" or more manufactured by Asahi Denka. Examples of hindered amines include “Sanol LS2626”, “Sanol LS765”, “Sanol LS770”, “Sanol LS744”, “Tinuvin 144”, “Tinuvin 622LD”, “Mark LA57”, “Mark LA67”, “Mark LA62”. ”,“ Mark LA68 ”,“ Mark LA63 ”,“ Smilizer TPS ”,“ Smilizer TP-D ”for thioethers,“ Mark 2112 ”,“ Mark PEP 8 ”,“ Mark PEP ”for phosphites -24G "," Mark PEP.36 "," Mark 329K "," Mark HP.10 ", and hindered phenols and hindered amine antioxidants are particularly preferable. Furthermore, these may be modified with a substituent such as an alkoxysilyl group capable of undergoing a crosslinking reaction with the material forming the crosslinked film.

  For the protective layer, polyvinyl butyral resin, polyarylate resin (polycondensate of bisphenol A and phthalic acid, etc.), polycarbonate resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyamide resin, acrylic resin Insulating resin such as polyacrylamide resin, polyvinyl pyridine resin, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol resin, polyvinyl pyrrolidone resin may be contained. In this case, the insulating resin can be added at a desired ratio, thereby suppressing adhesiveness with the charge transport layer formed in contact with the protective layer, coating film defects due to heat shrinkage and repelling, and the like. Can do.

The protective layer is formed by applying a protective layer-forming coating solution containing the above-described constituent materials onto the charge transport layer and curing it.
Since the protective layer is formed using the above-described charge transport material, it is preferable to add a catalyst to the protective layer forming coating solution or to use the catalyst when preparing the protective layer forming coating solution.
Catalysts used include inorganic acids such as hydrochloric acid, acetic acid, phosphoric acid and sulfuric acid, organic acids such as formic acid, propionic acid, oxalic acid, p-toluenesulfonic acid, benzoic acid, phthalic acid and maleic acid, potassium hydroxide, water An alkali catalyst such as sodium oxide, calcium hydroxide, ammonia, triethylamine, or a solid catalyst insoluble in the system can also be used.

  In addition, when forming a protective layer containing a phenolic resin having a cross-linked structure, in order to remove the catalyst used at the time of synthesis from the obtained resin, the resin is put into an appropriate solvent such as methanol, ethanol, toluene, ethyl acetate or the like. It is preferable to dissolve and perform treatment such as washing with water, reprecipitation using a poor solvent, or treatment using an ion exchange resin or an inorganic solid.

  For example, as an ion exchange resin, Amberlite 15, Amberlite 200C, Amberlyst 15E (above, manufactured by Rohm and Haas); Dowex MWC-1-H, Dowex 88, Dowex HCR-W2 (above Levacit SPC-108, Levacit SPC-118 (above, Bayer); Diaion RCP-150H (Mitsubishi Kasei); Sumikaion KC-470, Duolite C26-C, Duolite C-433, Duolite-464 (above, manufactured by Sumitomo Chemical Co., Ltd.); Cation exchange resins such as Nafion-H (DuPont); Amberlite IRA-400, Amberlite IRA-45 (above, Rohm and Anion exchange resins such as (made by Haas) are listed.

Further, as the inorganic solid, an inorganic solid in which a group containing a protonic acid group such as Zr (O ₃ PCH ₂ CH ₂ SO ₃ H) ₂ or Th (O ₃ PCH ₂ CH ₂ COOH) ₂ is bonded to the surface. A polyorganosiloxane containing a protonic acid group such as a polyorganosiloxane having a sulfonic acid group; a heteropolyacid such as cobalt tungstic acid or phosphomolybdic acid; an isopolyacid such as niobic acid, tantalic acid or molybdic acid; silica gel, alumina, Single metal oxides such as chromia, zirconia, CaO, MgO; complex metal oxides such as silica-alumina, silica-magnesia, silica-zirconia, zeolites; clay minerals such as acid clay, activated clay, montmorillonite, and kaolinite Metal sulfates such as LiSO4 and MgSO4; zirconia phosphate, lanthanum phosphate, etc. Genus _{phosphate; LiNO 3, Mn (NO 3} ) 2 and the like of a metal nitrate; group containing an amino group of a solid such as obtained by reacting aminopropyltriethoxysilane on silica gel is bonded to the surface Inorganic solids: Polyorganosiloxanes containing amino groups such as amino-modified silicone resins.

  For the coating liquid for forming the protective layer, alcohols such as methanol, ethanol, propanol and butanol; ketones such as acetone and methyl ethyl ketone; tetrahydrofuran; ethers such as diethyl ether and dioxane; Can be used. In order to apply the dip coating method generally used for the production of the photoreceptor, an alcohol solvent, a ketone solvent, or a mixed solvent thereof is preferable. In addition, the boiling point of the solvent used is preferably 50 to 150 ° C., and these can be arbitrarily mixed and used.

Since the solvent is preferably an alcohol solvent, a ketone solvent, or a mixed solvent thereof, the charge transport material used for forming the protective layer to be used should be soluble in these solvents. preferable.
Further, the amount of the solvent can be arbitrarily set, but if the amount is too small, the constituent material is likely to be precipitated. Therefore, the amount of the solvent is preferably 0.5 to 30 wt. Parts, more preferably 1 to 20 parts by weight.

  Coating methods for forming a protective layer using a coating solution for forming a protective layer include blade coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating. A usual method such as can be used. However, when a required film thickness cannot be obtained by a single application, the necessary film thickness can be obtained by applying a plurality of times. In addition, when performing the multiple application | coating several times, a heat processing may be performed every time of application | coating, and may be after carrying out multiple application | coating several times.

After applying the coating liquid for forming the protective layer on the charge transport layer, a curing process is performed.
In the case where the protective layer contains a phenolic resin having a charge transporting ability and having a crosslinked structure, usually, during the curing treatment, the crosslinking reaction of the phenol derivative is promoted to increase the mechanical strength of the protective layer. For this, the curing temperature is high and the curing time is preferably longer.
The curing temperature during the curing treatment is preferably 100 to 170 ° C, more preferably 100 to 150 ° C, and even more preferably 100 to 140 ° C. The curing time is preferably 30 minutes to 2 hours, more preferably 30 minutes to 1 hour.

Further, as an atmosphere for performing the curing treatment (crosslinking reaction), a gas atmosphere (inert gas atmosphere) inert to so-called oxidation such as nitrogen, helium, and argon is effective. When the crosslinking reaction is performed in an inert gas atmosphere, the curing temperature can be set higher than in an air atmosphere (oxygen-containing atmosphere), and the curing temperature is 100 to 160 ° C. (preferably 110 to 150 ° C.). Is possible. The curing time can be 30 minutes to 2 hours (preferably 30 minutes to 1 hour).
In the case of using the compound represented by the general formula (I), the curing temperature is most when the site represented by “— (X1) _m1- (R1) _m2 —Y” is composed of “—CH ₂ —OH”. It is preferable to perform the curing treatment in the above preferable temperature range because the influence of the electrical characteristics due to the above tends to be large and is sensitive to oxidation.

Furthermore, it is preferable to use a curing catalyst during the curing treatment.
Examples of the curing catalyst include bissulfonyldiazomethanes such as bis (isopropylsulfonyl) diazomethane, bissulfonylmethanes such as methylsulfonyl p-toluenesulfonylmethane, and sulfonylcarbonyldiazomethanes such as cyclohexylsulfonylcyclohexylcarbonyldiazomethane, 2 -Sulfonylcarbonyl alkanes such as methyl-2- (4-methylphenylsulfonyl) propiophenone, nitrobenzyl sulfonates such as 2-nitrobenzyl p-toluenesulfonate, alkyl and aryl sulfonates such as pyrogallol trismethanesulfonate (G) benzoin sulfonates such as benzoin tosylate, N- (trifluoromethylsulfonyloxy) phthalimide N-sulfonyloxyimides, pyridones such as (4-fluorobenzenesulfonyloxy) -3,4,6-trimethyl-2-pyridone, 2,2,2-trifluoro-1-trifluoromethyl-1 Photoacid generators such as sulfonate esters such as-(3-vinylphenyl) -ethyl-4-chlorobenzenesulfonate, onium salts such as triphenylsulfonium methanesulfonate and diphenyliodonium trifluoromethanesulfonate, protonic acid or Lewis Examples thereof include compounds obtained by neutralizing acids with Lewis bases, mixtures of Lewis acids and trialkyl phosphates, sulfonic acid esters, phosphate esters, onium compounds, and carboxylic anhydride compounds.

Compounds obtained by neutralizing a protonic acid or Lewis acid with a Lewis base include halogenocarboxylic acids, sulfonic acids, sulfuric acid monoesters, phosphoric acid mono- and diesters, polyphosphoric acid esters, boric acid mono- and diesters, and the like. Various amines such as monoethylamine, triethylamine, pyridine, piperidine, aniline, morpholine, cyclohexylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, or trialkylphosphine, triarylphosphine, trialkylphosphite, triaryl Compounds neutralized with phosphite, as well as NureCure 2500X, 4167, X-47-110, 3525, 5225 commercially available as acid-base blocking catalysts (trade name, King Ndasutori Co., Ltd.), and the like.
Examples of the compound obtained by neutralizing a Lewis acid with a Lewis base include compounds obtained by neutralizing a Lewis acid such as BF 3, FeCl ₃ , SnCl ₄ , AlCl ₃ , and ZnCl ₂ with the above Lewis base.

  Examples of the onium compound include triphenylsulfonium methanesulfonate, diphenyliodonium trifluoromethanesulfonate, and the like.

  Examples of the carboxylic anhydride compound include acetic anhydride, propionic anhydride, butyric anhydride, isobutyric anhydride, lauric anhydride, oleic anhydride, stearic anhydride, n-caproic anhydride, n-caprylic anhydride, and n-capric anhydride. , Palmitic anhydride, myristic anhydride, trichloroacetic anhydride, dichloroacetic anhydride, monochloroacetic anhydride, trifluoroacetic anhydride, heptafluorobutyric anhydride, and the like.

Specific examples of Lewis acids include, for example, boron trifluoride, aluminum trichloride, titanium chloride, ferric chloride, ferrous chloride, ferric chloride, zinc chloride, zinc bromide, stannous chloride. , Metal halides such as stannic chloride, stannous bromide, stannic bromide, organometallic compounds such as trialkylboron, trialkylaluminum, dialkylaluminum halide, monoalkylaluminum halide, tetraalkyltin , Diisopropoxyethyl acetoacetate aluminum, tris (ethyl acetoacetate) aluminum, tris (acetylacetonato) aluminum, diisopropoxy bis (ethyl acetoacetate) titanium, diisopropoxy bis (acetylacetonato) titanium, tetrakis (N-propylacetoacetate Zirconium, Tetrakis (acetylacetonato) zirconium, Tetrakis (ethylacetoacetate) zirconium, Dibutyl-bis (acetylacetonato) tin, Tris (acetylacetonato) iron, Tris (acetylacetonato) rhodium, Bis (acetyl) Acetonato) zinc, tris (acetylacetonato) cobalt metal chelate compounds, dibutyltin dilaurate, dioctyltin ester malate, magnesium naphthenate, calcium naphthenate, manganese naphthenate, iron naphthenate, cobalt naphthenate, copper naphthenate , Zinc naphthenate, zirconium naphthenate, lead naphthenate, calcium octylate, manganese octylate, iron octylate, cobalt octylate, zinc octylate, zirconium octylate, Tin chill acid, lead octylate, zinc laurate, magnesium stearate, aluminum stearate, calcium stearate, cobalt stearate, zinc stearate, and metal soaps such as stearate lead. These may be used individually by 1 type and may be used in combination of 2 or more type.
The amount of these curing catalysts used is not particularly limited, but is preferably from 0.1 to 20 parts by weight, particularly from 0.3 to 10 parts by weight, based on a total of 100 parts by weight of the solid content contained in the protective layer forming coating solution. preferable.

When an organic metal compound is used as a catalyst when forming the protective layer, it is preferable to add a polydentate ligand from the viewpoint of pot life and curing efficiency. Examples of such multidentate ligands include, but are not limited to, those shown below and those derived therefrom.
Specifically, β-diketones such as acetylacetone, trifluoroacetylacetone, hexafluoroacetylacetone, and dipivaloylmethylacetone; acetoacetates such as methyl acetoacetate and ethyl acetoacetate; bipyridine and derivatives thereof; glycine and its Derivatives; ethylenediamine and derivatives thereof; 8-oxyquinoline and derivatives thereof; salicylaldehyde and derivatives thereof; catechol and derivatives thereof; bidentate ligands such as 2-oxyazo compounds; diethyltriamine and derivatives thereof; nitrilotriacetic acid and derivatives thereof And tridentate ligands such as ethylenediaminetetraacetic acid (EDTA) and derivatives thereof. In addition to the organic ligands as described above, inorganic ligands such as pyrophosphoric acid and triphosphoric acid can be exemplified.
As the multidentate ligand, a bidentate ligand is particularly preferable, and specific examples include a bidentate ligand represented by the following general formula (IX-4) in addition to the above.

In the above formula (IX-4), R ³² and R ³³ each independently represent an alkyl group having 1 to 10 carbon atoms, a fluorinated alkyl group, or an alkoxy group having 1 to 10 carbon atoms.
Among the above, as the multidentate ligand, a bidentate ligand represented by the following general formula (IX-4) is more preferable, and R ³² and R ^{33 in the following} general formula (IX-4) are the same. Are particularly preferred. By making R ³² and R ^{33 the} same, the coordination power of the ligand near room temperature becomes strong, and the coating liquid for forming the protective layer can be further stabilized.

The compounding amount of the polydentate ligand can be arbitrarily set, but is preferably 0.01 mol or more, more preferably 0.1 mol or more, and still more preferably with respect to 1 mol of the organometallic compound used. 1 mole or more.
Oxygen permeability at 25 ° C. of the protective layer is preferably not more than ^{4 × 10 12 fm / s ·} Pa, more preferably not more than ^{3.5 × 10 12 fm / s ·} Pa, 3 × 10 12 More preferably, it is fm / s · Pa or less.
Here, the oxygen permeation coefficient is a measure representing the ease of oxygen gas permeation of the layer. However, it can be regarded as a substitute characteristic of the physical gap ratio of the layer if the view is changed. In addition, although the absolute value of the transmittance changes if the type of gas changes, there is almost no reversal of the magnitude relationship between the layers serving as specimens. Therefore, the oxygen permeation coefficient may be interpreted as a measure expressing the ease of general gas permeation.

That is, when the oxygen permeation coefficient at 25 ° C. of the protective layer satisfies the above conditions, gas hardly penetrates into the protective layer. Therefore, the penetration of the discharge product generated by the image forming process is suppressed, the deterioration of the compound contained in the protective layer is suppressed, the electrical characteristics can be maintained at a high level, and it is effective for high image quality and long life. It is.
Further, by making the oxygen transmission coefficient at 25 ° C. of the protective layer satisfy the above condition, a photoreceptor that can further improve electrical characteristics and achieve higher image quality can be obtained.
The thickness of the protective layer is preferably 0.5 to 15 μm, more preferably 1 to 10 μm, and more preferably 1 to 5 μm.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example at all. In the following description, “parts” means “parts by weight” unless otherwise specified.

[Production of composite particles]
<Composite particle A>
In a 2 L reaction flask equipped with a stirrer, a reflux condenser and a thermometer, 50.0 parts of melamine, 96.5 parts of 37% formalin, aqueous silica sol [manufactured by Nissan Chemical Industries, Snowtex S (trade name): SiO ₂ concentration of 30.5 wt%, pH 10.0, average particle diameter 7.9 nm] 20.7 parts was charged with 720 parts of water and the pH adjusted with 25% ammonia water 8.7.

  Next, the temperature of the mixture was increased while stirring, and the temperature was maintained at 70 ° C., and the mixture was reacted for 30 minutes to prepare an aqueous solution containing an initial condensate of melamine resin. Next, while maintaining the temperature at 70 ° C., an aqueous solution containing 10% by weight of dodecylbenzenesulfonic acid was added to the obtained aqueous solution containing the initial condensate to adjust the pH to 7.0. About 20 minutes later, the reaction system became cloudy, and particles in which silica fine particles were dispersed in the cured melamine resin were precipitated. Thereafter, the temperature was raised to 90 ° C. and the curing reaction was continued for 3 hours. After cooling, the resulting reaction solution was filtered and dried to obtain white composite particles A.

The volume average particle diameter of the obtained composite particles A was 0.3 μm as measured by a laser diffraction / scattering particle size distribution measuring apparatus [Mastersizer 2000 (trade name) manufactured by Malvern, Inc.]. The number average particle diameter d ₅₀ is 0.27 μm, and the small diameter side particle ratio (particle diameter is (1/2) × d ₅₀ or less particles / total number of particles) is 5% by number, large diameter side particle ratio. The number of particles having a particle size of (3/2) × d ₅₀ or less / the total number of particles was 15% by number.

  When this composite particle A was observed with a scanning electron microscope (SEM) as it was, and observed with a transmission electron microscope-energy-dispersive X-ray analysis (TEM-EDX) in the state of a slice piece, It was confirmed that the shape was spherical and the colloidal silica was unevenly distributed near the surface of the composite particle A. Moreover, it was confirmed that the surface of the composite particle A is uneven, and the protrusion is formed of colloidal silica.

<Composite particle B>
In a 2 L reaction flask equipped with a stirrer, a reflux condenser and a thermometer, 50.0 parts of melamine, 96.5 parts of 37% formalin, aqueous silica sol [manufactured by Nippon Aerosil Co., Ltd., RY40 (trade name): SiO ₂ concentration 30.5 wt%, pH 10.0, average particle size 40 nm] 20.7 parts and water 720 parts were charged, and the pH was adjusted to 8.5 with 25% aqueous ammonia. Thereafter, the temperature of the mixture was increased while stirring, and the temperature was maintained at 70 ° C., and the mixture was reacted for 30 minutes to prepare an aqueous solution containing an initial condensate of melamine resin.

  Next, while maintaining the temperature at 70 ° C., an aqueous solution containing 10% by weight of dodecylbenzenesulfonic acid was added to the aqueous solution containing the obtained initial condensate to adjust the pH to 7.0. After about 25 minutes, the reaction system became cloudy, and particles in which silica fine particles were dispersed in the cured melamine resin were precipitated. Thereafter, the temperature was raised to 90 ° C. and the curing reaction was continued for 3 hours. After cooling, the resulting reaction solution was filtered and dried to obtain white composite particles B.

The volume average particle size of the obtained composite particles B was 1.65 μm as measured by a laser diffraction / scattering particle size distribution measuring apparatus [Mastersizer 2000 (trade name) manufactured by Malvern, Inc.]. The number average particle diameter d ₅₀ is 1.5 μm, and the small diameter side particle ratio (particle diameter is (½) × d ₅₀ or less / number of all particles) is 10% by number, large diameter side particle ratio. (The number of particles having a particle size of (3/2) × d ₅₀ or less / the total number of particles) was 7% by number.

  When this composite particle A was observed with a scanning electron microscope (SEM) as it was, and observed with a transmission electron microscope-energy-dispersive X-ray analysis (TEM-EDX) in the state of a slice piece, It was confirmed that the shape was spherical and the colloidal silica was unevenly distributed near the surface of the composite particle A. Moreover, it was confirmed that the surface of the composite particle A is uneven, and the protrusion is formed of colloidal silica.

<Composite particle C>
In a 2 L reaction flask equipped with a stirrer, a reflux condenser and a thermometer, 50.0 parts of melamine, 96.5 parts of 37% formalin, aqueous silica sol [manufactured by Nissan Chemical Industries, Snowtex S (trade name): The SiO ₂ concentration was 30.5 wt%, pH 10.0, average particle size 7.9 nm] 133.5 parts, and 1820 parts of water were charged, and the pH was adjusted to 8.5 with 25% aqueous ammonia. Thereafter, the temperature of the mixture was increased while stirring, and the temperature was maintained at 70 ° C., and the mixture was reacted for 30 minutes to prepare an aqueous solution containing an initial condensate of melamine resin.

Next, while maintaining the temperature at 70 ° C., an aqueous solution containing 10% by weight of dodecylbenzenesulfonic acid was added to the aqueous solution containing the obtained initial condensate to adjust the pH to 7.0. After about 25 minutes, the reaction system became cloudy, and particles in which silica fine particles were dispersed in the cured melamine resin were precipitated. Thereafter, the temperature was raised to 90 ° C. and the curing reaction was continued for 3 hours. After cooling, the resulting reaction solution was filtered and dried to obtain white composite particles C.
The volume average particle size of the obtained composite particles C was 0.05 μm as measured by a laser diffraction / scattering particle size distribution measuring apparatus [Mastersizer 2000 (trade name) manufactured by Malvern, Inc.]. The number average particle diameter d ₅₀ is 0.03 μm, the small diameter side particle ratio (particle diameter (1/2) × d ₅₀ or less particles / total number of particles) is 15% by number, and the large diameter side particle ratio (particle size) The number of particles having a diameter of (3/2) × d ₅₀ or less / the total number of particles) was 10% by number.

  When this composite particle C was observed with a scanning electron microscope (SEM) as it was, and was observed with a transmission electron microscope-energy-dispersive X-ray analysis (TEM-EDX) in a sliced state, It was confirmed that the shape was spherical and the colloidal silica was unevenly distributed near the surface of the composite particle A. Moreover, it was confirmed that the surface of the composite particle A is uneven, and the protrusion is formed of colloidal silica.

<Composite particle D>
Into a 1 L beaker, 500 parts of methanol and 10 parts of methyltriethoxysilane were added, and then 100 parts of composite particles A were added and stirred. After the methanol was distilled off with an evaporator, the extracted particles were heated at 120 ° C. for 1 hour. To obtain composite particles D subjected to hydrophobic treatment.
The volume average particle diameter of the obtained composite particles D was 0.3 μm as measured by a laser diffraction / scattering particle size distribution analyzer [Mastersizer 2000 (trade name) manufactured by Malvern, Inc.]. The number average particle diameter d ₅₀ is 0.27 μm, and the small diameter side particle ratio (particle diameter is (½) × d ₅₀ or less / total number of particles) is 4% by number, large diameter side particle ratio. The number of particles having a particle size of (3/2) × d ₅₀ or less / the total number of particles was 18% by number.

  A summary of the composition and the like of the composite particles is shown in Table 1 below.

-Preparation of toner and developer-
[Manufacture of toner base particles]
(Adjustment of resin fine particle dispersion)
A mixture of 370 g of styrene, 30 g of n-butyl acrylate, 8 g of acrylic acid, 24 g of dodecanethiol and 4 g of carbon tetrabromide was dissolved in 6 g of a nonionic surfactant (Nonipol 400: manufactured by Sanyo Chemical Co., Ltd.) and anion Ion exchange in which 10 g of a surfactant (Neogen SC: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) is emulsion-polymerized in a flask in which 550 g of ion-exchanged water is dissolved, and 4 g of ammonium persulfate is dissolved in the flask while slowly mixing for 10 minutes. 50 g of water was added.
After carrying out nitrogen substitution, the inside of the flask was stirred and heated in an oil bath until the contents reached 70 ° C., and emulsion polymerization was continued for 5 hours. As a result, a resin fine particle dispersion in which resin fine particles having an average particle diameter of 150 nm, a glass transition temperature Tg = 58 ° C., and a weight average molecular weight Mw = 11500 was obtained. The solid content concentration of this dispersion was 40% by weight.

(Adjustment of colorant dispersion (1))
・ Carbon black (Mogal L: Cabot): 60g
・ Nonionic surfactant (Nonipol 400: Sanyo Chemical Co., Ltd.): 6g
・ Ion exchange water: 240g
The above components are mixed, dissolved, stirred for 10 minutes using a homogenizer (Ultra Turrax T50: manufactured by IKA), and then dispersed with an optimizer (colorant (carbon) having an average particle size of 250 nm. Black) A colorant dispersant (1) in which particles were dispersed was prepared.

(Adjustment of colorant dispersion (2))
Cyan pigment (CI Pigment Blue 15: 3): 60 g
-Nonionic surfactant (Nonipol 400: manufactured by Sanyo Chemical Co., Ltd.): 5g
・ Ion exchange water: 240g
The above components are mixed, dissolved, stirred for 10 minutes using a homogenizer (Ultra Turrax T50: manufactured by IKA), and then dispersed with an optimizer (Cyan having an average particle diameter of 250 nm). Pigment) A colorant dispersant (2) in which particles were dispersed was prepared.

(Adjustment of colorant dispersion (3))
Magenta pigment (CI Pigment Red 122): 60 g
-Nonionic surfactant (Nonipol 400: manufactured by Sanyo Chemical Co., Ltd.): 5g
・ Ion exchange water: 240g
The above components are mixed, dissolved, stirred for 10 minutes using a homogenizer (Ultra Turrax T50: manufactured by IKA), and then dispersed with an optimizer (Magenta having an average particle size of 250 nm). Pigment) A colorant dispersant (3) in which particles were dispersed was prepared.

(Adjustment of colored dispersion (4))
Yellow pigment (CI Pigment Yellow 180): 90 g
-Nonionic surfactant (Nonipol 400: manufactured by Sanyo Chemical Co., Ltd.): 5g
・ Ion exchange water: 240g
The above components are mixed, dissolved, stirred for 10 minutes using a homogenizer (Ultra Turrax T50: manufactured by IKA), then dispersed with an optimizer and a colorant having an average particle size of 250 nm (Yellow) Pigment) A colorant dispersant (4) in which particles were dispersed was prepared.

(Release agent dispersion)
Paraffin wax (HNP0190: Nippon Seiwa Co., Ltd., melting point 85 ° C.): 100 g
Cationic surfactant (Sanisol B50: manufactured by Kao Corporation): 5 g
・ Ion exchange water: 240g
The above components were dispersed in a round stainless steel flask using a homogenizer (Ultra Turrax T50: manufactured by IKA) for 10 minutes, and then dispersed with a pressure discharge type homogenizer, and the average particle size was 550 nm. A release agent dispersion in which the mold agent particles were dispersed was prepared.

<Adjustment of toner mother particle K>
-Resin fine particle dispersion: 234 parts-Colorant dispersion (1): 30 parts-Release agent dispersion: 40 parts-Polyaluminum hydroxide (Pho2S manufactured by Asada Chemical Co., Ltd.): 0.5 parts-Ion exchange water : 600 parts The above components were mixed and dispersed in a round stainless steel flask using a homogenizer (Ultra Turrax T50: manufactured by IKA), and then stirred at 40 ° C while stirring the flask in an oil bath for heating. Until heated. After maintaining at 40 ° C. for 30 minutes, it was confirmed that aggregated particles having a volume average particle diameter D50v of 4.5 μm were generated. Further, the temperature of the heating oil bath was raised and maintained at 56 ° C. for 1 hour, and the volume average particle diameter D50v was 5.3 μm.

  Thereafter, 26 parts by weight of the resin fine particle dispersion was added to the dispersion containing the aggregated particles, and then the temperature of the heating oil bath was raised to 50 ° C. and held for 30 minutes. Subsequently, 1N sodium hydroxide was added to the dispersion containing the aggregated particles to adjust the pH of the system to 7.0, and then the stainless steel flask was sealed, and stirring was continued using a magnetic seal while continuing the stirring. Heat to 0 ° C. and hold for 4 hours. After cooling, the toner base particles were separated by filtration, washed four times with ion exchange water, and then lyophilized to obtain toner base particles K1. The volume average particle diameter D50v of the toner base particles K1 is 5.9 μm, and the average shape factor SF is 123.

<Adjustment of toner base particle C>
Toner mother particles C1 were obtained in the same manner as K1 except that the colored particle dispersion (2) was used instead of the colored particle dispersion (1). The toner base particle C1 has a volume average particle diameter D50v of 5.8 μm and an average shape factor SF of 120.

<Adjustment of toner base particles M>
Toner mother particles M1 were obtained in the same manner as K1 except that the colored particle dispersion (3) was used instead of the colored particle dispersion (1). The toner mother particles M1 had a volume average particle diameter D50v of 5.5 μm and an average shape factor SF of 122.

<Adjustment of toner base particle Y>
Toner mother particles Y1 were obtained in the same manner as K1 except that the colored particle dispersion (4) was used instead of the colored particle dispersion (1). The toner base particle Y1 has a volume average particle diameter D50v of 5.9 μm and an average shape factor SF of 120.

[Manufacture of carriers]
Ferrite particles (average particle size: 50 μm): 100 parts Toluene: 14 parts Styrene / methacrylate copolymer (styrene / methacrylate molar ratio: 90/10): 2 parts Carbon black (R330: manufactured by Cabot Corporation) : 0.2 part First, the above components excluding ferrite particles were stirred with a stirrer for 10 minutes to prepare a dispersed coating solution, and then this coating solution and ferrite particles were put into a vacuum degassing type kneader. After stirring for 30 minutes at ° C, the carrier was obtained by further depressurizing while heating and degassing and drying. This carrier had a volume resistivity of 10 ¹¹ Ωcm at an applied electric field of 1000 V / cm.

  K1, C1, M1, and Y1 are used as toner base particles, and 1 part of metatitanic acid (average primary particle size 40 nm, i-butyltrimethoxysilane treatment), silica (average) as an external additive with respect to 100 parts by weight of toner. In addition to 1.5 parts (primary particle size 12 nm, dimethyldimethoxysilane treatment, gas phase oxidation method), 5 L Henschel so that the composite particles or melamine resin particles have the combinations shown in Table 2 below After blending with a mixer at a peripheral speed of 30 m / s × 15 minutes, coarse particles were removed using a sieve having an opening of 45 μm, and toners 1 to 6 having different compositions of external additives were obtained.

In addition, the melamine resin particle | grains are particles which consist only of a resin component, and Nippon Shokubai Co., Ltd. poster S (volume average particle diameter of 0.3 micrometer) was used. It should be noted that the surface shape of the eposter S is smooth with no irregularities.
Further, 100 parts of the carrier and 6 parts of each toner were stirred with a V-blender at 40 rpm × 20 minutes, and sieved with a sieve having an opening of 212 μm, thereby developing each developer 1-6. ~ 6 was obtained. Each toner is negatively charged when supplied to the surface of the photoreceptor during development (that is, the normal polarity is negative).

[Production of photoconductor]
<Photoreceptor 1>
To 170 parts by weight of n-butyl alcohol in which 4 parts by weight of polyvinyl butyral resin (S-REC BM-S, manufactured by Sekisui Chemical Co., Ltd.) is dissolved, 30 parts by weight of an organic zirconium compound (acetylacetone zirconium butyrate) and an organic silane compound (γ-amino) 3 parts by weight of propyltrimethoxysilane) was added, mixed and stirred to obtain a coating solution for forming an undercoat layer.
This coating solution is dip-coated on an aluminum support having an outer diameter of 40 mm roughened by a honing treatment, air-dried at room temperature for 5 minutes, and then the support is heated to 50 ° C. for 10 minutes, It was placed in a constant temperature and humidity chamber at 50 ° C. and 85% RH (dew point 47 ° C.), and a humidification hardening acceleration treatment was performed for 20 minutes. Then, it put in the hot air dryer and dried for 10 minutes at 170 degreeC, and formed the undercoat layer.

Next, gallium chloride phthalocyanine is used as a charge generation material, 15 parts by weight thereof, 10 parts by weight of vinyl chloride-vinyl acetate copolymer resin (VMCH, manufactured by Nippon Union Carbide) and 300 parts by weight of n-butyl alcohol. The resulting mixture was dispersed in a sand mill for 4 hours.
The obtained dispersion was dip-coated on the undercoat layer and dried to form a charge generation layer having a thickness of 0.2 μm.

  Next, 40 parts by weight of N, N'-bis (3-methylphenyl) -N, N'-diphenylbenzidine and 60 parts by weight of bisphenol Z polycarbonate resin (molecular weight 40,000) were added to 235 parts by weight of tetrohydrofuran and mono A coating solution obtained by sufficiently dissolving and mixing in 100 parts by weight of chlorobenzene was dip-coated on the charge generation layer and dried to form a charge transport layer having a thickness of 20 μm, whereby Photoreceptor 1 was obtained.

<Photoreceptor 2>
5 parts of the following compound 1, 7 parts of resol type phenolic resin (PL-4852, Gunei Chemical Co., Ltd.), 0.03 part of methylphenylpolysiloxane, and 20 parts of isopropanol are dissolved and protected. A layer forming coating solution was obtained. This coating solution was applied onto the charge transport layer of the photoreceptor 1 by a dip coating method and dried at 130 ° C. for 40 minutes to form a protective layer having a thickness of 3 μm, whereby a photoreceptor 2 was obtained.

<Photoreceptor 3>
2 parts of the following compound 2 and 2 parts of RESITOP PL4852 (manufactured by Gunei Chemical) were dissolved in 10 parts of isopropyl alcohol to obtain a coating solution for forming a protective layer. This protective layer forming coating solution is dip-coated on the charge transport layer of the photoconductor prepared under the same conditions as the photoconductor 1 except that the film thickness of the charge transport layer is 22 μm, air-dried at room temperature for 30 minutes, and then 140 The photosensitive member 3 was obtained by drying at 60 ° C. for 60 minutes to form a protective layer having a thickness of 4 μm.

<Photoreceptor 4>
The constituent materials shown below were dissolved in 5 parts of isopropyl alcohol, 3 parts of tetrahydrofuran and 0.3 part of distilled water, 0.5 parts of ion exchange resin (Amberlyst 15E) was added, and the mixture was stirred at room temperature for 24 hours. Decomposition was performed.
-Constituent material-
Compound 2: 2 parts Methyltrimethoxysilane: 2 parts Tetramethoxysilane: 0.5 parts Fluorine graft polymer (ZX007C: manufactured by Fuji Kasei): 0.5 parts Silica: 0.3 parts Is obtained by subjecting a silica sol obtained by the sol-gel method to HMDS (hexamethyldisilazane) treatment, drying and grinding, and is a spherical monodispersed silica having a specific gravity of 1.50 and an average particle diameter of 140 nm.

Next, 0.1 part of aluminum trisacetylacetonate (Al (aqaq) ₃ ) and 3,5-di-t-butyl-4- are used for the solution obtained by filtering and separating the ion exchange resin from the hydrolyzed solution. 0.4 parts of hydroxytoluene (BHT) is added, and this coating solution is applied onto the charge transport layer of the photoreceptor 1 by a ring-type dip coating method, air-dried at room temperature for 30 minutes, and then heat-treated at 150 ° C. for 1 hour. Then, a protective layer having a film thickness of about 3 μm was formed to obtain a photoreceptor 4.

[Cleaning device]
As the cleaning device, the following cleaning device 1, cleaning device 2, and cleaning device 3 (all of which are process cartridges) having the configuration shown in FIG. 4 were used. Details of the configuration of each part and usage conditions during cleaning are as follows.

-Cleaning device 1-
<First cleaning unit>
(1) Roll-shaped brush member Brush material: conductive nylon, fiber thickness: 2 denier (about 17 μm), electric resistance: 1 × 10 ⁵ Ω, hair length: 4 mm, fiber density: 50,000 / inch ² , the amount of biting into the photoconductor: about 1.0 mm, peripheral speed: 60 mm / s, rotation direction: reverse rotation with respect to the rotation direction of the photoconductor, brush application bias: +200 V

(2) Collection roll member Material: phenol resin in which conductive carbon is dispersed, electric resistance: 1 × 10 ⁶ Ω, flexural modulus (JIS K7203): 100 MPa, wear amount (JIS K6902): 2 mg, Rockwell hardness (JIS) K7202, M scale): 120, amount of biting into the brush member: 1.5 mm, peripheral speed: 70 mm / s, applied bias: +600 V

(3) Scraper Material: SUS304, thickness: 80 μm, amount of biting into the recovery roll member: 1.3 mm, free length (free length): 8.0 mm.

<Second cleaning unit>
(1) Roll-shaped brush member Brush material: conductive nylon, fiber thickness: 2 denier (about 17 μm), electric resistance: 1 × 10 ⁵ Ω, hair length: 4 mm, fiber density: 50,000 / inch ² , the amount of biting into the photoconductor: about 1.0 mm, peripheral speed: 60 mm / s, rotation direction: reverse rotation with respect to the rotation direction of the photoconductor, brush application bias: −400 V

(2) Collection roll member Material: phenol resin in which conductive carbon is dispersed, electric resistance: 1 × 10 ⁶ Ω, flexural modulus (JIS K7203): 100 MPa, wear amount (JIS K6902): 2 mg, Rockwell hardness (JIS) K7202, M scale): 120, biting amount into the brush member: 1.5 mm, peripheral speed: 70 mm / s, applied bias: -800 V

(3) Scraper Material: SUS304, thickness: 80 μm, amount of biting into the recovery roll member: 1.3 mm, free length (free length): 8.0 mm.

-Cleaning device 2-
<First cleaning unit>
(1) Rolled brush member Brush material: conductive nylon, fiber thickness: 2 denier (about 50 μm), electrical resistance: 1 × 10 ⁵ Ω, length of bristle length: 2 mm, fiber density: 150,000 / inch ² , the amount of biting into the photoconductor: about 0.5 mm, peripheral speed: 60 mm / s, rotation direction: reverse rotation with respect to the rotation direction of the photoconductor, brush application bias: +200 V

(2) Collection roll member Material: phenol resin in which conductive carbon is dispersed, electric resistance: 1 × 10 ⁶ Ω, flexural modulus (JIS K7203): 100 MPa, wear amount (JIS K6902): 2 mg, Rockwell hardness (JIS) K7202, M scale): 120, amount of biting into the brush member: 1.5 mm, peripheral speed: 70 mm / s, applied bias: +600 V

(3) Scraper Material: SUS304, thickness: 80 μm, amount of biting into the recovery roll member: 1.3 mm, free length (free length): 8.0 mm.

<Second cleaning unit>
(1) Rolled brush member Brush material: conductive nylon, fiber thickness: 2 denier (about 50 μm), electrical resistance: 1 × 10 ⁵ Ω, length of bristle length: 2 mm, fiber density: 150,000 / inch ² , the amount of biting into the photoconductor: about 0.5 mm, peripheral speed: 60 mm / s, rotation direction: reverse rotation with respect to the rotation direction of the photoconductor, brush application bias: -400 V

(2) Collection roll member Material: phenol resin in which conductive carbon is dispersed, electric resistance: 1 × 10 ⁶ Ω, flexural modulus (JIS K7203): 100 MPa, wear amount (JIS K6902): 2 mg, Rockwell hardness (JIS) (K7202, M scale): 120, amount of biting into the member into the brush: 1.5 mm, peripheral speed: 70 mm / s, applied bias: -800 V

(3) Scraper Material: SUS304, thickness: 80 μm, amount of biting into the recovery roll member: 1.3 mm, free length (free length): 8.0 mm.

-Cleaning device 3-
The cleaning device 3 has the same configuration and cleaning as the cleaning device 2 except that the bias applied to the roll brush member in the second cleaning unit of the cleaning device 2 is +400 V and the bias applied to the collection roll member is +800 V. It is used under conditions.

(Examples 1-9 and Comparative Examples 1-6)
In the evaluation of the example, the evaluation machine 1 is the one that incorporates the cleaning device 1 based on the Color DocuTech 60 manufactured by Fuji Xerox having the image forming unit having the configuration shown in FIG.
Further, an image forming unit having the configuration shown in FIG. 2 is obtained by modifying the charger of Color DocuTech 60 manufactured by Fuji Xerox into a contact-type roll charger as shown in FIG. 3 and incorporating the cleaning device 2 as an evaluation machine 2. Based on Fuji Xerox's Color DocuTech 60 equipped with a cleaning device 3 was used as an evaluation machine 3. The contact charging roll used was Tokai Rubber Industrial 6C14.
For this evaluation machine 1 to evaluation machine 3, the photoreceptors 1 to 4 and the toners 1 to 6 (developers 1 to 6) are combined as shown in Table 3 below, and the high temperature and high humidity (28 ° C., 80%) and low-temperature and low-humidity (10 ° C., 20% RH) conditions were evaluated for filming, photoconductor scratches and photoconductor wear by 20,000 sheets each in color mode, for a total of 40,000 sheets. The image blur was evaluated after 100,000 halftone images (image density 30%) were printed in a high temperature and high humidity environment (28 ° C., 85% RH). The results are shown in Table 4 below.

  The image blur, filming, photoconductor scratches, and photoconductor wear shown in Table 4 are based on the following measurement methods and evaluation criteria.

[Image blur]
Image blur was evaluated as follows. First, after 100,000 sheets of halftone images (image density 30%) have been printed under a high temperature and high humidity environment (28 ° C., 85% RH), the surface of the photoreceptor is removed to remove water-soluble discharge products. Only a part was wiped with water.
Thereafter, a halftone image (image density of 30%) is printed again, and an image portion corresponding to a portion where the surface of the photosensitive member is wiped with water and a portion where the surface is not wiped with a reflection type density measuring device (X-rite). The density difference (ΔSAD) was measured and evaluated according to the following criteria. Note that image blur (character bleeding) corresponds to the density difference of the halftone image printed after wiping the surface of the photoconductor, and thus this evaluation method was used instead.
A: ΔSAD is 0.15 or less.
○: ΔSAD is more than 0.15 and less than 0.4.
X: ΔSAD is 0.4 or more.

[Filming]
Filming on the photoreceptor after the durability test was judged by sensory evaluation by visual observation. Judgment criteria are as follows.
A: No sticking at all.
○: There is a slight sticking, but the level does not affect the image quality.
X: The surface is clearly fixed, and appears as color streaks and white streaks in the image quality.

[Photoconductor scratches]
The photoconductor scratch was evaluated by measuring the surface of the photoconductor after the durability test by measuring a 10-point average roughness (Rz) using a surface roughness meter (Surfcom 1400A manufactured by Tokyo Seimitsu Co., Ltd.). Judgment criteria are as follows.
A: Rz is 1.5 μm or less.
○: Rz exceeds 1.5 μm and is less than 2.5 μm (a level at which there is no problem in image quality).
X: Rz is 2.5 μm or more (white streaks appear on the image).

(Photoconductor wear)
Regarding the wear of the photoreceptor, the film thickness of the photoreceptor before and after the running test was measured with an eddy current film thickness meter, and the difference was judged. The values shown in Table 4 indicate the amount of wear per 1000 revolutions of the photoreceptor.

As can be seen from Table 4, in the image forming apparatus of the present invention, the composite surface in which inorganic fine particles are dispersed and contained in the resin particles is added to the toner in the brush cleaning method, so that the surface of the photoreceptor can be damaged over a long period of time. While suppressing, image blur and filming can also be suppressed.
In addition, by using a photoconductor having a protective layer containing a resin having a crosslinked structure, the abrasion resistance is improved, so that the scratch on the photosensitive surface caused by brush rubbing is greatly reduced and the brush tip is damaged. It is possible to suppress rubbing along the photoconductor and uniformly rub the photoreceptor. Therefore, the effect of removing toner components such as discharge products and external additives from the composite particles from the surface of the photoreceptor can be expressed more uniformly.

1 is a schematic diagram illustrating an example of an image forming apparatus of the present invention. It is a schematic diagram showing an example of an image forming unit used in the image forming apparatus of the present invention. It is a schematic diagram which shows the other example of the image forming unit used for the image forming apparatus of this invention. It is a schematic diagram showing an example of a cleaning device used in the image forming apparatus of the present invention. 2 is a schematic cross-sectional view showing an example of a photoreceptor used in the image forming apparatus of the present invention. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Photoconductor 2 ... Charging device (non-contact charger)
3 ... Exposure device 4 ... Developing device 5 ... Transfer device 7 ... Cleaning device 8 ... Charging device (contact charger)
DESCRIPTION OF SYMBOLS 11 ... Conductive base | substrate 12 ... Undercoat layer 13 ... Charge generation layer 14 ... Charge transport layer 15 ... Protective layer 16 ... Photosensitive layer 40 ... Image forming apparatus 41 ... Image forming unit 47 ... Belt conveying apparatus 48 ... Conveying belts 49, 50 51, 52, 53, 54 ... tension roll 55 ... suction roll 56 ... fixing roll 57 ... storage tray 58 ... tension roll 59 ... belt cleaner 60 ... recording material supply device 700 ... housing 701a, 701b ... roll brush member 702a , 702b ... recovery roll members 703a, 703b ... scrapers 704a, 704b, 705a, 705b ... shaft 706 ... mounting brackets

Claims (10)

A charging step for charging the surface of the latent image carrier that can rotate in one direction, a latent image forming step for forming a latent image by irradiating the charged surface of the latent image carrier, and a developer containing toner. The latent image is developed on the surface of the latent image carrier after the toner image is transferred to the transfer body, the development step of developing the latent image to form a toner image, the transfer step of transferring the toner image to the transfer body. And a cleaning step in which the toner is cleaned by a cleaning means provided with a conductive brush that is in contact with the surface of the latent image carrier and is applied with a voltage.
The cleaning means includes a first conductive brush and a second conductive brush arranged along the rotation direction of the latent image carrier, and the polarity of the voltage applied to the first conductive brush And the polarity of the voltage applied to the second conductive brush is opposite,
An image forming method, wherein the toner includes composite particles in which inorganic fine particles are dispersed and contained in resin particles.   The image forming method according to claim 1, wherein the composite particles have a volume average particle diameter in a range of 0.05 to 2 μm. The number average particle diameter of the composite particles is taken as d _50, in the particle size distribution of the composite particles,
The ratio of the number of particles having a particle size of (1/2) × d ₅₀ or less with respect to the total number of particles, and the ratio of the number of particles having a particle size of (3/2) × d ₅₀ or more with respect to the total number of particles, respectively. 2. The image forming method according to claim 1, wherein the number is 20% by number or less.   2. The image forming method according to claim 1, wherein the inorganic fine particles are dispersed in the vicinity of the surface of the composite particle so as to form a convex portion on the surface of the composite particle.   The image forming method according to claim 1, wherein the composite particles include a resin containing a nitrogen element.   The image forming method according to claim 1, wherein the resin containing a nitrogen atom is a melamine resin. 2. The image forming method according to claim 1, wherein a shape factor SF of the toner defined by the following formula (1) is in a range of 100 to 140. 3.
Formula (1) SF = 100 × π × ML ² / 4A
[In the formula (1), SF represents the shape factor of the toner, ML represents the absolute maximum length of the toner particles, and A represents the projected area of the toner particles. ]   2. The image forming method according to claim 1, wherein the outermost surface layer of the latent image carrier contains a resin having a structural unit having a charge transporting ability and having a crosslinked structure.   A structure in which the resin having a structural unit having charge transporting ability and having a crosslinked structure has at least one charge transporting ability selected from a hydroxyl group, a carboxyl group, an alkoxysilyl group, an epoxy group, a thiol group, and an amino group The image forming method according to claim 8, wherein the image forming method is a phenol resin or a siloxane resin containing a unit. A latent image carrier that is rotatable in one direction; a charging unit that charges the surface of the latent image carrier; and a latent image forming unit that forms a latent image by irradiating the charged surface of the latent image carrier with light. A developer containing toner is supplied to the surface of the latent image carrier on which the latent image is formed, thereby developing the latent image to form a toner image; and transferring the toner image to the transfer target And a transfer means that contacts the surface of the latent image carrier and is used in a state where a voltage is applied, and after the toner image is transferred to the transfer target by the conductive brush Cleaning means for cleaning the toner remaining on the surface of the latent image carrier,
An image in which the charging unit, the latent image forming unit, the developing unit, the transfer unit, and the cleaning unit are arranged in this order around the latent image carrier along the rotation direction of the latent image carrier. In the forming device,
The cleaning means includes a first conductive brush and a second conductive brush arranged along the rotation direction of the latent image carrier, and the polarity of the voltage applied to the first conductive brush And the polarity of the voltage applied to the second conductive brush is opposite,
An image forming apparatus, wherein the toner includes composite particles in which inorganic fine particles are dispersed and contained in resin particles.

Images