JP5445108B2 - Electrophotographic photosensitive member, image forming method, image forming apparatus, and process cartridge for image forming apparatus - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive member with extremely little deterioration in properties such as wear durability and electrostatic durability without causing an increase in potential of an exposed portion even after long-term use, and copying using the electrophotographic photosensitive member. The present invention relates to an electrophotographic image forming apparatus, an image forming method, and a process cartridge, such as a printer, a printer, a facsimile, or a composite machine thereof.

  In recent years, from the viewpoints of saving office space, expanding business opportunities, etc., high speed, downsizing, colorization, high image quality, and easy maintenance are desired for electrophotographic apparatuses. These are regarded as problems to be solved by developing an electrophotographic photosensitive member because they are related to improvement in characteristics and durability of the electrophotographic photosensitive member. From the viewpoint of improving ease of maintenance, there is a reduction in the replacement frequency of the electrophotographic photosensitive member. This is to reduce the main image defects derived from the electrophotographic photosensitive member as much as possible over a long period of time, which is nothing but the extension of the life of the electrophotographic photosensitive member. In addition, in recent years, there have been many reports on development relating to extending the life of electrophotographic photosensitive members because they are related to the improvement of the image quality of output images over a long period of time.

  In order to achieve a long life of the electrophotographic photosensitive member, it is an important issue to improve durability against various hazards that the electrophotographic photosensitive member receives from the image forming process. The hazards mentioned here can be broadly classified into two types: mechanical hazards and electrical hazards (electrostatic hazards).

  An example of a mechanical hazard is one derived from blade cleaning, which is one of means for removing toner remaining on the electrophotographic photosensitive member after transfer of the image forming process (so-called toner cleaning process). Blade cleaning is a means for forcibly removing toner from the electrophotographic photosensitive member by contacting an elastic member (so-called cleaning blade) on the photosensitive member, and has a large toner removing ability in a small space. This is very effective for miniaturization of an electrophotographic apparatus.

  However, on the other hand, the elastic member is brought into direct contact with the electrophotographic photosensitive member and rubbed, so that the mechanical stress on the electrophotographic photosensitive member becomes very large, which is taken up as one of the problems for extending the life. There are many cases. For example, there is a problem of so-called poor wear durability in which wear of the electrophotographic photosensitive member is accelerated by the stress applied to the surface of the electrophotographic photosensitive member by the cleaning blade. Apart from this, when the cleaning blade moves on the surface of the electrophotographic photosensitive member, the friction is large due to the magnitude of the stress, and it cannot slide stably between the cleaning blade and the electrophotographic photosensitive member. As an example, a problem of so-called poor lubricity in which toner removal is insufficient.

  Therefore, as a means for solving the former problem, a technique of laminating a high hardness protective layer on the surface of the electrophotographic photosensitive member has been proposed (see, for example, Patent Documents 1 to 5). To solve the latter problem, a so-called solid lubricant supplying means is incorporated in the image forming system on the surface of the electrophotographic photosensitive member, and the solid lubricant is continuously supplied to the surface of the photosensitive member (for example, Patent Documents 6 to 8). And a technique for incorporating a solid lubricant on the surface of the electrophotographic photosensitive member (for example, see Patent Documents 9 to 11). Both technologies are positioned as important technologies that satisfy the customer demand trends described at the beginning. From the viewpoint of miniaturization and ease of maintenance, an electrophotographic photosensitive member having a high hardness surface layer containing a solid lubricant is used. It is considered the most suitable device.

  As a surface layer technique in which a solid lubricant is included, for example, as described in Patent Documents 12 and 13, means for making fluororesin fine particles exist as a solid lubricant in the vicinity of the surface of a photoreceptor is proposed. Although it has been shown that the frictional resistance between the surface of the electrophotographic photosensitive member and the cleaning blade can be reduced by these technical means, in general, the wear rate of the fluororesin fine particles is high and the electrophotographic photosensitive member is used. As the process proceeds, there is a problem that the fluororesin on the surface of the electrophotographic photosensitive member (more specifically, between the surface of the electrophotographic photosensitive member and the cleaning blade) decreases, and the effect is not sustained. This is not suitable from the viewpoint of extending the life of the photoreceptor.

  Further, in Patent Document 14, fluororesin fine particles are added as a solid lubricant in the vicinity of the surface of the electrophotographic photosensitive member, and inorganic fine particles are separately added to improve wear durability. Although it has been shown that it is possible to improve lubricity and wear durability, as described above, since the wear durability of the fluororesin fine particles themselves is low, the use of the electrophotographic photosensitive member of the configuration concerned Since the ratio of the fluororesin fine particles exposed on the surface is reduced and the surface of the electrophotographic photosensitive member is less worn, the fluororesin fine particles cannot be sufficiently supplied from the inside of the electrophotographic photosensitive member. There is a problem that the effect of lubricity is difficult to sustain, and these techniques are not suitable from the viewpoint of extending the life of the electrophotographic photosensitive member.

  As described above, the problem that the effect is difficult to be sustained when a solid lubricant is contained on the surface of the electrophotographic photosensitive member originates from the lubrication mechanism of the solid lubricant. That is, many solid lubricants known in the world are known to exhibit lubricity due to cleavage of the crystal interface, and in order to obtain an electrophotographic photoreceptor that meets the object of the present invention using this, It is important to form a structure in which the lubricant is present on the surface of the electrophotographic photosensitive member over a long period of time by controlling the cleavage speed of the solid lubricant, that is, the wear speed.

  Moreover, an electrostatic hazard is demonstrated. In a normal image forming process, an electric charge is applied to the surface of the electrophotographic photosensitive member, and after charging to a predetermined potential, the electric charge applied to the surface via the photosensitive member is removed by exposure to the electrophotographic photosensitive member. At this time, electrostatic stress is applied to the electrophotographic photosensitive member as charges pass through each layer (for example, a surface layer, a charge generation layer, a charge transport layer, and an intermediate layer) of the electrophotographic photosensitive member.

  Currently, the most widely used electrophotographic photoreceptors are composed of organic materials, and in the current electrophotographic processes in which repeated charging and discharging are repeated, the organics constituting the electrophotographic photoreceptor are included. The material gradually changes in quality due to the electrostatic hazard, and the electrophotographic characteristics are deteriorated as exemplified by generation of charge traps in the layer and change in chargeability. In particular, it is known that a decrease in chargeability has a great influence on the image quality of an output image, and causes serious problems such as a decrease in image density, background contamination, and image homogeneity during continuous output.

  Solutions to the problems concerning such electrostatic hazards have been proposed in Patent Documents 15 to 20, for example. However, the charge injection from the support can be suppressed without causing an increase in the potential of the exposed area, and the deterioration in characteristics such as electrostatic durability is extremely small even with long-term use, and high-quality images with few defects continue. An electrophotographic photosensitive member that can be obtained in an automated manner, and an image forming method, an image forming apparatus, and a process cartridge using the electrophotographic photosensitive member have not been obtained, and it is desired to provide them promptly. It is.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to incorporate a solid lubricant having a controlled crystal interface cleavage rate into a cross-linked surface layer so that it can be electrophotographic even when used. The amount of solid lubricant present on the outermost surface of the photoconductor is kept above a certain level, and it is possible to reduce the frictional resistance between the electrophotographic photoconductor surface and the cleaning blade over a long period of time. It is to provide a photographic photoreceptor. Another object of the present invention is to provide an image forming method, an image forming apparatus, and a process cartridge using such an electrophotographic photosensitive member.

As a result of intensive studies to achieve the above object, the present inventor has at least an intermediate layer, a photosensitive layer, and a surface layer in this order on a conductive support, and the surface layer has at least a radical polymerizable compound and a photo radical polymerization. An electrophotographic photosensitive member comprising an initiator and formed by polymerization by light energy irradiation means, wherein the surface layer contains organic-inorganic composite fine particles comprising at least a fluororesin and an inorganic material, and the organic-inorganic composite fine particles By specifying the area ratio of the fluororesin contained in the photoreceptor surface, the frictional resistance between the electrophotographic photoreceptor surface and the cleaning blade can be reduced over a long period of time, and the wear resistance is long. It has been found that a long-life electrophotographic photoreceptor can be produced. As a result, even when the electrophotographic photosensitive member is repeatedly used, there is little filming such as toner cleaning failure and paper dust, and long-life electrophotography having durability against mechanical hazards and electrostatic hazards derived from the image forming process. It has been confirmed that a photoreceptor can be provided. The present invention has been made based on these findings.
Therefore, according to the present invention, means for solving the above-described problems are as follows.

(1) It has at least an intermediate layer, a photosensitive layer, and a surface layer in this order on a conductive support, and the surface layer is composed of at least a radical polymerizable compound and a photo radical polymerization initiator, and is polymerized by light energy irradiation means. The surface layer contains organic-inorganic composite fine particles composed of at least a fluororesin and an inorganic material, and the volume average particle diameter Dv of the organic-inorganic composite fine particles is 0.05 μm or more and 3.0 μm or less. The proportion of the inorganic material in the organic / inorganic composite fine particles is 3 vol% or more and 40 vol% or less, and the ratio of the organic / inorganic composite fine particles in the surface layer is 5 vol% or more and 40 vol% or less. An electrophotographic photoreceptor.
(2) In the electrophotographic photosensitive member according to the above (1), the average value of the area ratio of the fluororesin contained in the organic-inorganic composite fine particles to the photosensitive member surface is 5% or more and 50% or less, and the area The ratio coefficient of variation is 0.10 or less.
(3) In the electrophotographic photosensitive member according to the above (1) or (2), the fluororesin contained in the organic-inorganic composite fine particles is a polytetrafluoroethylene, a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, a tetra It contains at least one of fluoroethylene / hexafluoropropylene copolymer and polyvinylidene fluoride.
(4) In the electrophotographic photosensitive member according to any one of (1) to (3), the inorganic material contained in the organic-inorganic composite fine particles is any one of aluminum oxide, titanium oxide, silicon oxide, and molybdenum sulfide. It contains at least a seed.
(5) The electrophotographic photosensitive member according to any one of (1) to (4) above, wherein the functional group of the radical polymerizable compound is an acryloyloxy group and / or a methacryloyloxy group.
(6) The electrophotographic photosensitive member according to any one of (1) to (5) above, wherein the radical polymerizable compound is a radical polymerizable compound having no charge transporting structure.
(7) The electrophotographic photosensitive member according to (6) above, wherein the radical polymerizable compound having no charge transporting structure has three or more functional groups.
(8) The electrophotographic photosensitive member according to any one of (1) to (5) above, wherein the radical polymerizable compound is a radical polymerizable compound having a charge transporting structure.
(9) The electrophotographic photosensitive member according to (8) above, wherein the charge transporting portion of the radical polymerizable compound having the charge transporting structure has a triarylamine structure.
(10) The electrophotographic photosensitive member according to (8) or (9) is characterized in that the radical polymerizable compound having the charge transporting structure has one functional group.
(11) In the electrophotographic photosensitive member according to any one of (1) to (10), the radical polymerizable compound has a radical polymerizable compound having no charge transport structure and a radical polymerization having a charge transport structure. It is a mixture of an ionic compound.
(12) The electrophotographic photosensitive member according to any one of (1) to (11) above, wherein the elastic power of the surface layer is 40% or more.
(13) The electrophotographic photosensitive member according to any one of (1) to (12), wherein the photosensitive layer is formed of a stack of a charge generation layer and a charge transport layer.

(14) A charging process for charging at least the electrophotographic photosensitive member using the electrophotographic photosensitive member according to any one of (1) to (13), and a surface of the electrophotographic photosensitive member charged by the charging process. A latent image forming process for forming an electrostatic latent image on the substrate, a developing process for attaching toner to an image portion of the electrostatic latent image formed by the latent image forming process, and a visible image formed by the developing process to be transferred And an image forming method comprising repeatedly performing a transfer process of transferring to the substrate.

(15) The electrophotographic photosensitive member according to any one of (1) to (13) above, at least a charging unit for charging the electrophotographic photosensitive member, and an electrophotographic photosensitive member charged by the charging unit An image provided integrally with one means selected from a latent image forming means for forming an electrostatic latent image on the surface and a developing means for attaching toner to the image portion of the electrostatic latent image formed by the latent image forming means. An image forming apparatus comprising a process cartridge for an image forming apparatus, the process cartridge for the image forming apparatus being detachable.

(16) The electrophotographic photosensitive member according to any one of (1) to (13) above, at least a charging unit for charging the electrophotographic photosensitive member, and an electrophotographic photosensitive member charged by the charging unit An image having one means selected from a latent image forming means for forming a latent image on the surface and a developing means for attaching toner to an image portion of an electrostatic latent image formed by a latent image forming device. Process cartridge for forming apparatus.

  According to the present invention, conventional problems can be solved, and without causing an increase in the potential of the exposed area, even when used over a long period of time, characteristic deterioration is extremely small, and high-quality images with few defects can be continuously obtained. An electrophotographic photosensitive member that can be used, and an image forming method, an image forming apparatus, and a process cartridge can be provided.

It is a schematic diagram of the form which coat | covered the surface of the inorganic particle with the fluororesin. It is a schematic diagram of the form which made the inorganic particle adhere to the surface of a fluororesin particle. It is a schematic diagram of the form which disperse | distributed the inorganic material in the fluororesin. It is a figure for demonstrating the method of observing the exposure state of the fluororesin in the photoreceptor surface. 1 is a schematic cross-sectional view showing an example of an electrophotographic photosensitive member of the present invention. It is a cross-sectional schematic diagram showing another example of the electrophotographic photosensitive member of the present invention. It is a cross-sectional schematic diagram showing another example of the electrophotographic photosensitive member of the present invention. 1 is a schematic diagram illustrating an example of an image forming apparatus of the present invention. It is the schematic which shows an example of the process cartridge of this invention. It is the schematic of the measuring apparatus which measures the friction coefficient of the surface of the electrophotographic photosensitive member of this invention.

  In order to achieve the long life of the electrophotographic photosensitive member, it is important to impart durability to various hazards received from each process in image formation as described above. In particular, two hazards, a mechanical hazard that is applied in a cleaning process for removing toner remaining on the surface of the electrophotographic photosensitive member, and an electrostatic hazard that is received from a charging process or a transfer process, give a large stress to the photosensitive member. It is considered to cause a change in the characteristics of the photoreceptor and to be an impeding factor for extending the life of the photoreceptor. Among these, in the present invention, it is a technology related to improvement in durability against mechanical hazards, and more specifically, a technology related to improvement in toner cleaning property and wear durability by reducing frictional resistance between the surface of the electrophotographic photosensitive member and the cleaning blade. It is.

  In order to improve the toner cleaning property and the wear durability, it is effective to add a solid lubricant to the surface of the electrophotographic photosensitive member. Solid lubricant is a solid used as a thin film or powder to protect the surface from damage during relative motion and reduce friction and wear, and its function mechanism is `` layered structure is relative motion of two objects It is said that it is cleaved by "or" is temporarily melted by frictional heat ". In particular, the former has a long history as a solid lubricant and is widely used. However, it is generally known that the wear durability is poor because it is a lubricant based on consumption because of its mechanism of expression.

  As a method of reducing the frictional resistance between the surface of the electrophotographic photosensitive member and the cleaning blade using such a lubricant, a mechanism for supplying the lubricant during the electrophotographic imaging process is provided, and solid lubrication is performed from the outside of the electrophotographic photosensitive member. And a method of supplying a solid lubricant near the surface of the electrophotographic photosensitive member. Either method is an effective means for reducing the frictional resistance between the two objects, but the design concept for developing lubricity between the two objects is considered to be slightly different. That is, the former method of supplying the solid lubricant from the outside of the electrophotographic photosensitive member can supply the necessary amount from the outside even if the solid lubricant is consumed. It is based on the design philosophy of complementing with "supply of solid lubricant". Although this method has a wide selection range of solid lubricants and can cover the entire surface of the electrophotographic photosensitive member, it has the feature that the wear of the surface of the electrophotographic photosensitive member is extremely reduced by the coated lubricant. It has a cost handicap due to consumption of the agent and a size handicap such as the need to provide a supply mechanism. On the other hand, the latter method of incorporating a solid lubricant on the surface of an electrophotographic photosensitive member cannot supply a solid lubricant that exhibits a function by consumption during use, that is, the usable amount of the solid lubricant that can be used is determined at an initial stage. Therefore, “efficient use of solid lubricant” is necessary for the design concept. Compared to the former external supply type, this method is easy to reduce costs because the amount of solid lubricant used is small, and is also excellent in space saving because it does not require a feeder. However, since the solid lubricant exposed on the surface of the electrophotographic photosensitive member is quickly consumed, the electrophotographic photosensitive member containing the solid lubricant is generally poor in wear durability or has wear durability. However, it is often difficult to maintain lubricity.

  The present invention has been made to remedy this problem of an electrophotographic photosensitive member containing a solid lubricant. In other words, the consumption (wear) rate of organic solid lubricants is controlled by organic / inorganic composite technology, and one is given priority by lowering the solid lubricant wear rate and the electrophotographic photoreceptor surface layer bulk wear rate. An electrophotographic photoconductor with excellent wear durability that achieves both wear durability and lubricity, and does not lose lubricity even after long-term use. It has been found that can be obtained, and the present invention has been achieved.

Hereinafter, the present invention will be described in more detail with reference to the drawings.
The photoreceptor of this embodiment is a laminate having at least an intermediate layer, a photosensitive layer, and a surface layer in this order on a conductive support. The photosensitive layer may have a single layer structure or a multilayer structure as long as it has a charge generation function and a charge transport function. An example of the embodiment will be described with reference to FIGS.

The electrophotographic photoreceptor shown in FIG. 5 is an example in which the photosensitive layer is a single layer, and a photosensitive layer 36 mainly composed of a charge generation material and a charge transport material is formed on the conductive support 31 and the intermediate layer 32. And the surface layer 35 is provided. The surface layer 35 described here is a crosslinkable surface layer described below.
The electrophotographic photoreceptor shown in FIGS. 6 and 7 is an example in the case where the photosensitive layer is laminated, and a charge generation layer 33 having a charge generation function on the conductive support 31 and the intermediate layer 32, and a charge transport function. The charge transporting layer 34 bearing the charge is separated and laminated. In the case of taking this embodiment, as shown in the drawing, the order of stacking the charge generation layer and the charge transport layer is not particularly limited and can be properly used according to the application. The surface layer 35 is formed on the outermost surface of the photoreceptor. Laminated.

[Conductive support]
The conductive support is not particularly limited as long as it has a volume resistance of 10 ¹⁰ Ω · cm or less, and can be appropriately selected according to the purpose. For example, aluminum, nickel, chromium, nichrome, Metals such as copper, gold, silver, platinum, etc .; metal oxides such as tin oxide and indium oxide deposited or sputtered on a film or cylindrical plastic, paper, or aluminum, aluminum alloy, nickel, stainless steel And a pipe subjected to surface treatment such as cutting, super-finishing, polishing, etc. can be used after forming a raw pipe by a method such as extruding and drawing them. Further, an endless nickel belt and an endless stainless steel belt disclosed in JP-A-52-36016 can also be used as a support.

In addition, those in which conductive powder is dispersed in an appropriate binder resin and coated on the support can also be used as the support in the present invention.
Examples of the conductive powder include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc and silver, or metal oxide powder such as conductive tin oxide and ITO. Etc. The binder resin used at the same time includes polystyrene resin, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester resin, polyvinyl chloride resin, vinyl chloride-vinyl acetate. Copolymer, polyvinyl acetate resin, polyvinylidene chloride resin, polyarylate resin, phenoxy resin, polycarbonate resin, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral resin, polyvinyl formal resin, polyvinyl toluene resin, poly-N-vinyl carbazole, Thermoplastic, thermosetting resin, or photocurable resin such as acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, alkyd resin, and the like can be given.

  The conductive layer can be provided by dispersing and applying these conductive powder and binder resin in a suitable solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, toluene and the like.

  Furthermore, it is electrically conductive by a heat shrinkable tube in which the conductive powder is contained in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, Teflon (registered trademark) on a suitable cylindrical substrate. Those provided with a conductive layer can also be used favorably as the conductive support of the present invention.

  As will be described later, a highly coherent laser may be used to form a latent image in the electrophotographic process. As described above, the support is often made of a metal material, many of which have a high surface reflectance. When an electrophotographic photosensitive member is produced by applying the inorganic semiconductor material of the present invention on a support having such characteristics, interference occurs between writing light and reflected light from the support, resulting in image defects. Cheap. For this reason, when the reflectance of a support body is high, it is preferable to give an unevenness | corrugation to the surface of a support body and to reduce a reflectance. Further, protrusions and the like that are potentially present on the support sometimes cause image defects when the photosensitive layer or the like is laminated. By roughening this to an appropriate surface roughness, it is possible to provide a support surface with few protruding protrusions. As the surface irregularities, arithmetic ten-point average surface roughness (Rz) measured by the method described in JIS B0601-1982 was used as a representative characteristic value.

  As a method for measuring the surface roughness (Rz), for example, Surfcom 1400D (manufactured by Tokyo Seimitsu Co., Ltd.) was used, and the surface roughness (Rz) was measured with respect to an evaluation length of 2.5 mm and a reference length of 0.5 mm. Measurement points were 80 mm from both ends of the drum in the axial direction, 3 points in the center of the drum, and 4 types of 90 degrees in the circumferential direction. A total of 12 points were measured, and the average value was defined as the surface roughness (Rz) of the drum. The surface roughness (Rz) is preferably 0.6 μm or more. If Rz is smaller than this, moire due to writing light is likely to occur, which is not preferable. Further, even if Rz is large, there is no significant problem in use. However, if Rz is too large, it is difficult to form the intermediate layer uniformly, so care must be taken. From this viewpoint, the surface roughness (Rz) of the support is preferably 3.0 μm or less.

  Examples of the roughening method include honing and centerless polishing. The honing process is preferably used because it is inexpensive and the surface roughness can be easily adjusted. There are dry and wet processing methods for the honing process, and any of them may be used. Wet (liquid) honing is a method in which a powdery abrasive (abrasive grain) is suspended in a liquid such as water and sprayed onto the surface of the support at high speed to roughen the surface. The pressure, speed, amount, type, shape, size, hardness, specific gravity or suspension concentration of the abrasive can be controlled. Similarly, the dry honing process is a method in which an abrasive is sprayed onto the support surface with air at a high speed to roughen the surface, and the surface roughness can be controlled in the same manner as the wet honing process. Examples of the abrasive used in these wet or dry honing processes include particles such as silicon carbide, alumina, zirconia, stainless steel, iron, glass beads, and plastic shots.

  However, in dry honing and liquid honing using amorphous alumina abrasive grains, the abrasive grains may pierce the surface of the support, and when an electrophotographic photosensitive member is produced, black spots on white images in the reversal development system, normal rotation It appears as white spots on a black image in the development system. In liquid honing using glass beads, it is difficult to control the roughness because the glass breaks immediately and pierces the support surface. Therefore, after roughening the support by liquid honing using spherical alumina abrasive grains or stainless abrasive grains as an abrasive, an intermediate layer and a photosensitive layer are formed to produce an electrophotographic photoreceptor. Is common. Further, in the roughening treatment of the support, an interference fringe prevention function from the viewpoint of processing time, amount of abrasive grains used, amount of energy consumption, and ease of removing residual abrasive grains from the roughened substrate. It is preferable to make the treatment conditions as mild as possible within the range satisfying the above and to keep the surface roughness (Rz) small.

[Middle layer]
The intermediate layer is provided for the purpose of preventing charge injection from the conductive support side, improving adhesion, preventing moire, improving coatability of the upper layer (photosensitive layer), and reducing residual potential.
The intermediate layer is made of a thermosetting resin and a fine powder composed of a metal oxide, such as titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide, or an inorganic pigment such as metal sulfide or metal nitride. It can be formed by using a coating solution which is individually or suitably selected from two or more and dispersed and prepared by a ball mill, a sand mill, an attritor or the like.

  As the inorganic pigment, high-purity titanium oxide is particularly preferable. The solvent for dispersing the inorganic pigment is preferably a ketone solvent, particularly cyclohexanone, cyclohexanol, methyl ethyl ketone, or methyl isobutyl ketone, in view of the solubility of the resin and the dispersibility of the inorganic pigment. By using these solvents, it is possible to disperse the inorganic pigment to the primary particle size and produce a uniform coating solution free from aggregates.

  As the resin used for the intermediate layer, considering that the photosensitive layer provided on the intermediate layer is coated and formed using a solvent, a resin having high resistance to general organic solvents, such as an acrylic resin, Examples are thermosetting resins such as alkyd resins, amino resins, and melamine resins.

  The intermediate layer can be formed by a roll coating method, a dip coating method, a spray coating method, a nozzle coating method, a blade coating method or the like using a coating solution. After applying the coating liquid, the formed coating film is cured by drying or heating. The film thickness of the intermediate layer is 0.1 to 20 μm, preferably 0.2 to 10 μm.

  By controlling the ratio (P / R) of the inorganic pigment (P) and thermosetting resin (R) used in the intermediate layer to 4/1 to 9/1 (weight ratio), it prevents the decrease in charge during repeated use. It becomes possible to do. In particular, it is preferable to use an alkyd resin and a melamine resin as the thermosetting resin in the composition. Here, when P / R is less than 4/1, the effect of preventing a decrease in charge during repeated use is small. On the other hand, when P / R exceeds 1 to 9/1, there is little effect for preventing the occurrence of minute granular soiling during repeated use.

(Photosensitive layer)
The photosensitive layer includes a stacked type photosensitive layer of a charge generation layer and a charge transport layer, and a single layer type photosensitive layer.

<Laminated photosensitive layer>
In the laminated photosensitive layer, independent layers are responsible for the charge generation function and the charge transport function. Therefore, the photosensitive layer has a structure in which at least a charge generation layer and a charge transport layer are stacked on a support. The order of stacking is not particularly limited, but many charge generation materials have poor chemical stability, and the charge generation efficiency decreases when exposed to acidic gases such as discharge products around the charger in the electrophotographic imaging process. Cause. For this reason, a charge transport layer is preferably laminated on the charge generation layer.

[Charge generation layer]
The charge generation layer is a layer mainly composed of a charge generation material having a charge generation function, and a binder resin can be used in combination as necessary. As the charge generation material, inorganic materials and organic materials can be used.

(Inorganic material)
Inorganic materials include crystalline selenium, amorphous selenium, selenium-tellurium, selenium-tellurium-halogen, selenium-arsenic compounds, and amorphous silicon. In amorphous silicon, dangling bonds that are terminated with hydrogen atoms or halogen atoms, or those that are doped with boron atoms, phosphorus atoms, or the like are preferably used.

(Organic materials)
On the other hand, a known material can be used as the organic material. For example, phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine, azulenium salt pigments, squaric acid methine pigments, azo pigments having a carbazole skeleton, azo pigments having a triarylamine skeleton, azo pigments having a diphenylamine skeleton, dibenzothiophene skeleton Azo pigments having a fluorenone skeleton, azo pigments having an oxadiazole skeleton, azo pigments having a bis-stilbene skeleton, azo pigments having a distyryl oxadiazole skeleton, azo pigments having a distyrylcarbazole skeleton, perylene Pigments, anthraquinone or polycyclic quinone pigments, quinoneimine pigments, diphenylmethane and triphenylmethane pigments, benzoquinone and naphthoquinone pigments, cyanine and azomethine pigments, Goido based pigments, and bisbenzimidazole pigments. These charge generation materials can be used alone or as a mixture of two or more.

(Binder resin)
As a binder resin used as necessary for the charge generation layer, polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, Examples include polyacrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, and polyvinyl pyrrolidone. These binder resins can be used alone or as a mixture of two or more. The amount of the binder resin is suitably 0 to 500 parts by mass, preferably 10 to 300 parts by mass with respect to 100 parts by mass of the charge generating material. The binder resin may be added before or after dispersion.

(Formation of charge generation layer)
Methods for forming the charge generation layer include a vacuum thin film preparation method and a casting method from a solution dispersion system. As the former method, a vacuum deposition method, a glow discharge decomposition method, an ion plating method, a sputtering method, a reactive sputtering method, a CVD method, or the like is used, and the above-described inorganic materials and organic materials can be satisfactorily formed. In addition, in order to provide the charge generation layer by the latter casting method, the inorganic or organic charge generation material described above, together with a binder resin, if necessary, tetrahydrofuran, dioxane, dioxolane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, cyclohexane. It can be formed by dispersing with a ball mill, attritor, sand mill, bead mill or the like using a solvent such as pentanone, anisole, xylene, methyl ethyl ketone, acetone, ethyl acetate, butyl acetate, etc., and applying the solution after appropriately diluting the dispersion. Moreover, leveling agents, such as a dimethyl silicone oil and a methylphenyl silicone oil, can be added as needed. The coating can be performed using a dip coating method, spray coating, bead coating, ring coating method or the like.

  The thickness of the charge generation layer provided as described above is suitably about 0.01 to 5 μm, preferably 0.05 to 2 μm.

[Charge transport layer]
The charge transport layer is a layer having a charge transport function, and is a layer mainly composed of a charge transport material or a polymer charge transport material and a binder resin.

(Binder resin)
The binder resin is not particularly limited and may be appropriately selected from known materials according to the purpose. For example, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer. Polymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene , Thermoplastic or thermosetting resins such as poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, and alkyd resin.

(Charge transport material)
The charge transport material is not particularly limited and may be appropriately selected depending on the purpose. For example, a known hole transport material having a hole transport structure such as triarylamine, hydrazone, pyrazoline, carbazole, Known electron transport materials having an electron transport structure such as an electron-withdrawing aromatic ring having condensed polycyclic quinone, diphenoquinone, cyano group, and nitro group can be mentioned. The hole transport material or electron transport material may be used alone or as a mixture of two or more.

  The content of the charge transport material in the charge transport layer is preferably 20% by mass to 80% by mass and more preferably 30% by mass to 70% by mass with respect to the total mass of the charge transport layer. When the content of the charge transport material in the charge transport layer is less than 20% by mass with respect to the total mass of the charge transport layer, the charge transport property of the charge transport layer is reduced, so that desired light attenuation characteristics cannot be obtained. If it is greater than 80% by mass, it may be worn more than necessary due to various hazards received by the photoreceptor from the electrophotographic process. On the other hand, when the content of the charge transport material in the charge transport layer is within the particularly preferable range, a desired light attenuating property can be obtained, and an electrophotographic photoreceptor with a small amount of wear can be obtained by use. This is advantageous.

(Polymer charge transport material)
The polymer charge transport material is a material having both the function of a binder resin described later and the function of a charge transport material. In particular, when the amorphous oxide described in the present invention is applied to the intermediate layer, by applying a polymer charge transporting material as the charge transporting material, a decrease in chargeability and the occurrence of soiling are suppressed. It is known from the study by the present inventors and is preferable.

  The polymer charge transport material is not particularly limited and may be a known material, but is preferably at least one polymer selected from polycarbonate, polyurethane, polyester and polyether. In particular, a polycarbonate containing a triarylamine structure exemplified in Japanese Patent No. 3852812 and Japanese Patent No. 3990499 in at least one of the main chain and the side chain is preferable from the viewpoint of wear durability and charge transportability.

  The polymer charge transport materials may be used alone or in combination of two or more. Moreover, you may use together with binder resin mentioned later from viewpoints, such as abrasion durability and film forming property. From the viewpoint of compatibility of charge transportability, when the polymer charge transport material and the binder are used in combination, the content of the polymer charge transport material is preferably 40% by mass to 90% by mass with respect to the total mass of the charge transport layer, 50 mass%-80 mass% is more preferable.

(Formation of charge transport layer)
The charge transport layer can be formed by dissolving or dispersing the charge transport material and the binder resin or the polymer charge transport material in a suitable solvent, applying the solution, and drying.
Since most of the constituent components of the charge transport layer are solid at normal temperature and pressure, a solvent having a high affinity with the constituent components is used in preparing the coating liquid. The solvent used here is not particularly limited as long as it is a known solvent generally used for painting and coating. The solvent to be used may be used independently, and 2 or more types may be mixed and used for it.
The coating method used for forming the charge transport layer is not particularly limited, and a commonly used coating method can be used. The coating method can be appropriately selected depending on the viscosity of the coating liquid, the desired thickness of the charge transport layer, and the like. A coating method may be selected. Examples include dip coating, spray coating, bead coating, ring coating, and the like.

  In addition, for the charge transport layer, if necessary, plasticizers such as dibutyl phthalate and dioctyl phthalate, silicone oils such as dimethyl silicone oil and methyl phenyl silicone oil, polymers or oligomers having a perfluoroalkyl group in the side chain, etc. A leveling agent can also be added.

  The thickness of the charge transport layer is preferably 50 μm or less and more preferably 45 μm or less from the viewpoint of resolution and responsiveness. The lower limit varies depending on the system to be used (particularly charging potential), but is preferably 5 μm or more.

The charge transport layer formed by the above means needs to be heated by some means from the viewpoint of electrophotographic characteristics and film viscosity, and the solvent as described above needs to be removed from the film. As the thermal energy, air, nitrogen or other gas, steam, various heat media, infrared rays, or electromagnetic waves can be used, and heating is performed from the coating surface side or the support side.
The heating temperature is preferably 100 ° C. or higher and 170 ° C. or lower. When the temperature is lower than 100 ° C., it is confirmed that the organic solvent in the film cannot be sufficiently removed, and the electrophotographic characteristics are deteriorated and the wear durability is reduced. On the other hand, when the treatment is performed at a temperature higher than 170 ° C., a surface-like defect or crack may occur on the surface, or peeling may occur at the interface with the adjacent layer. Further, when the volatile component in the photosensitive layer is sprayed to the outside, it is not preferable because desired electrical characteristics may not be obtained.

<Single layer type photosensitive layer>
The photosensitive layer having a single layer structure is a layer having a charge generation function and a charge transport function at the same time. The photosensitive layer can be formed by dissolving or dispersing a charge generating substance, a charge transporting substance, and a binder resin in a suitable solvent, and applying and drying them. Moreover, a plasticizer, a leveling agent, antioxidant, etc. can also be added as needed.
As the binder resin, in addition to the binder resin previously mentioned in the charge transport layer, the binder resin mentioned in the charge generation layer may be mixed and used. Polymer charge transport materials can also be used favorably. The amount of the charge generation material with respect to 100 parts by mass of the binder resin is preferably 5 parts by mass to 40 parts by mass, and the amount of the charge transport material is preferably 190 parts by mass or less, and more preferably 50 parts by mass to 150 parts by mass.
The single-layer type photosensitive layer is a dip coating method, spray coating, a coating solution in which a charge generating material, a binder resin and a charge transport material are dispersed together with a dispersing machine using a solvent such as tetrahydrofuran, dioxane, dichloroethane, and cyclohexane. It can be formed by coating with bead coat or ring coat.
The thickness of the single-layer type photosensitive layer is preferably 5 μm to 25 μm.

[Surface layer]
The surface layer of the present invention is a crosslinkable surface layer that contains a specific lubricant, is composed of at least a radical polymerizable compound and a photo radical polymerization initiator, and is formed by polymerization using light energy irradiation means. In the present invention, as the radically polymerizable compound, a radically polymerizable compound having no charge transporting structure may be used alone, or a radically polymerizable compound having a charge transporting structure may be used alone. May be used in combination. When a radically polymerizable compound that does not have a charge transporting structure is used alone as a radically polymerizable compound, a charge transporting material that does not have a radically polymerizable functional group is used in order to support the surface layer with a charge transporting function. It is preferable to do. Various additives described in the present specification may be added for the purpose of imparting other functions to the surface layer.

<Lubricant>
The lubricant used in the present invention is organic-inorganic composite fine particles of a fluororesin and an inorganic material. Fluororesin is known to have very high lubricity, and the theory that the lubrication manifestation mechanism is due to slipping of flaky crystals is dominant, but in the present invention, the flaky crystal size is the inorganic material. The main feature is that the consumption rate of the lubricant is controlled by controlling it with the composite, and the wear durability and the maintenance of lubricity are compatible by adding the lubricant to the surface layer of the electrophotographic photoreceptor. .
(Method of compounding)
As a method for compounding the fluororesin and the inorganic material, generally used means can be used, and there is no particular limitation. As a specific example, an inorganic material is added in the process of dispersing a fluoromonomer in an aqueous medium or an inert medium that does not easily affect the polymerization reaction, and particleizing by emulsion polymerization or suspension polymerization. A method of filling materials, a wet manufacturing method such as forming composite fine particles by polymerizing the surface of inorganic fine particles and a fluoromonomer, and a method of applying strong shear to a mixed powder of fluororesin fine particles and inorganic fine particles to form a composite Examples include dry manufacturing methods such as (mechanical alloying method).

(Structure of composite fine particles)
As the structural form of the composite fine particles formed using a fluororesin and an inorganic material, (1) a form in which the surface of the inorganic particle is coated with a fluororesin (schematic diagram: FIG. 1), (2) inorganic on the surface of the fluororesin particle Examples include a form in which particles are attached (schematic diagram: FIG. 2), and (3) a form in which an inorganic material is dispersed in a fluororesin (schematic diagram: FIG. 3). Among these, organic-inorganic composite fine particles represented by (2) and (3) are preferable from the viewpoint of consumption rate control, which is an important factor for satisfying the present invention.

Even when the fluororesin-coated inorganic fine particles as shown in the above (1) are used, it is possible to exhibit lubricity and wear durability to some extent, but this is not preferable for the reason described later.
That is, when the organic-inorganic composite structure as in (1) is used, the fluororesin becomes rich near the particle surface and sufficient lubrication is achieved, but the consumption rate is the consumption rate of the fluororesin bulk. Is very fast. On the other hand, as the organic / inorganic composite fine particles having the form (1) are worn, the ratio of the fluororesin is reduced, so that it is difficult to develop lubricity, and the wear rate itself reflects the bulk properties of the inorganic material. Slowly, the cleavage frequency of the flaky crystal of the fluororesin becomes small, so that the expression of lubricity tends to be difficult. On the other hand, when the organic-inorganic composite structure as shown in the above (2) and (3) is taken, the cleavage frequency of the fluororesin is easily maintained and the cleavage size can be easily controlled. As a result, it is easy to obtain a composite structure in which both consumption speed and lubricity are compatible and the characteristics are not easily changed by particle wear.

(Fluorine resin)
The fluororesin is not limited as long as it is generally known as a material exhibiting lubricity. For example, polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), tetrafluoroethylene / hexafluoropropylene / perfluoroalkyl Vinyl ether copolymer (EPE), tetrafluoroethylene / ethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), chlorotrifluoroethylene / ethylene copolymer (ECTFE), polyvinylidene fluoride (PVDF), A polyvinyl fluoride (PVF) etc. are mentioned. Of these, polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), and tetrafluoroethylene / hexafluoropropylene copolymer (FEP) exhibiting relatively high lubricity are suitable. .

(Inorganic material)
Inorganic materials include metal powders such as copper, tin, aluminum, indium, silica, tin oxide, zinc oxide, titanium oxide, alumina, indium oxide, antimony oxide, bismuth oxide, calcium oxide, antimony-doped tin oxide, tin And metal oxides such as indium oxide doped with metal, metal fluorides such as tin fluoride, calcium fluoride, and aluminum fluoride, and inorganic materials such as potassium titanate, boron nitride, and molybdenum sulfide. In the present invention, inorganic materials that lower the electrical characteristics of the electrophotographic photosensitive member, specifically, low-resistance materials and electrostatically unstable materials such as forming charge traps are not preferred. Metal oxides and metal fluorides represented by alumina are preferably used, and among them, it has a high insulation property, a high thermal stability, and a hexagonal close-packed structure with high wear resistance. Type alumina is particularly useful from the viewpoint of suppressing image blur and improving wear resistance. Molybdenum sulfide having properties as a solid lubricant as well as fluororesin is also useful. Such inorganic materials may be used alone or in combination of two or more.

(Composite composition ratio of fluororesin and inorganic material)
The composite composition ratio of the fluororesin and the inorganic material is preferably changed as appropriate depending on the selection of the lubricant wear rate. The compounding ratio varies depending on the fluororesin or inorganic material to be applied. However, if the proportion of the inorganic material in the organic-inorganic composite fine particles is 3 vol% or more and 40 vol% or less, it is the case where it is added to the surface layer of the electrophotographic photoreceptor. However, it is easy to obtain fine particles having both consumption speed control and lubrication. When the proportion of the inorganic material is smaller than 3 vol%, it is difficult to sufficiently control the wear rate of the fluororesin, and the composite effect cannot be enjoyed. When the proportion of the inorganic material is larger than 40% by weight, the lubricity of the fine particles tends to reflect the characteristics of the inorganic fine particles. For this reason, when the applied inorganic material has poor lubricity, the expression of lubricity becomes insufficient, which is not preferable. However, the inorganic material to be applied is not limited as long as it has a self-lubricating property such as molybdenum sulfide.

(Particle size of organic / inorganic composite fine particles)
The volume average particle size of primary particles of the organic / inorganic composite fine particles is preferably 0.05 μm or more and 3.0 μm or less. As a particle size measuring method, a laser diffraction particle size distribution measuring method generally used for measuring the particle size of particles having the volume particle size may be used. When the volume average particle size is smaller than 0.05 μm, the lubricity of the organic-inorganic composite fine particles is not sufficiently exhibited, which is not preferable. When the volume average particle size is larger than 3.0 μm, the surface roughness of the surface layer of the electrophotographic photosensitive member becomes large, and the toner on the surface of the photosensitive member slips through the surface concave portion even when it has lubricity. As a result, toner cleaning failure occurs, which is not preferable.

  The particle size measurement method includes geometric information of particles obtained by sieving, microscopic observation, etc., physical phenomena such as light diffraction and scattering, and dynamic properties of particles such as sedimentation velocity And a method utilizing a physical quantity depending on the particle diameter. In the present invention, the measurement method is not particularly limited as long as it is possible to measure a particle size of submicron order or more. Examples of such a particle size measuring method include a particle size measuring method using a zeta potential and a particle size measuring method using a photon correlation method (dynamic light scattering method). An example of a measuring instrument using the former method is an ELS-Z series manufactured by Otsuka Electronics Co., Ltd. as a zeta potential / particle size measuring system. Examples of measuring instruments using the latter method include UPA series manufactured by Nikkiso Co., Ltd. as a nanotrack particle size distribution measuring device, and LB-550 manufactured by HORIBA as a dynamic light scattering particle size distribution measuring device. . Unless otherwise specified, this is a volume average particle size measured by an ultracentrifugal automatic particle size distribution analyzer (CAPA-700, manufactured by Horiba, Ltd.), and a particle size corresponding to 50% of the cumulative distribution (Median series) ).

(Dispersant, surfactant)
The lubricating fine particles in the present invention can be surface-treated with at least one dispersant or surfactant. In particular, lubricating fine particles having a small particle diameter are preferable from the viewpoint of dispersibility. Lowering the dispersibility of lubricating fine particles not only increases the residual potential, but also lowers the transparency of the coating, causes defects in the coating, and decreases the wear resistance. There is a possibility that it will develop into a big problem. As the dispersant and surfactant, those commonly used can be used, but those capable of maintaining the insulating properties of the lubricating fine particles are preferable.

  The surface treatment amount varies depending on the average primary particle size of the lubricating fine particles used, but is preferably 3 to 30% by mass, more preferably 5 to 20% by mass, based on the weight of the lubricating fine particles. When the amount of the dispersant and the surfactant is less than this, the effect of dispersing the filler cannot be obtained, and when the amount is too large, the residual potential is remarkably increased. These surface treatment agents may be used alone or in combination of two or more.

<Method for measuring volume average particle size and particle size distribution>
For measurement of the volume average particle size and particle size distribution of the organic / inorganic composite fine particles, a liquid module is attached to a LS-230 type laser diffraction particle size distribution measuring device manufactured by Coulter and measured in a measurement range of 0.04 to 2000 μm. . As a measurement method, a trace amount of surfactant is added to 10 ml of pure water, 10 mg of a sample of organic-inorganic composite fine particles is added thereto, and the mixture is dispersed for 10 minutes with an ultrasonic disperser (ultrasonic homogenizer), and then measured for 90 hours. Measured once per second and the number of measurements, and the volume average particle size is calculated based on the result.

  In this invention, it measured using the laser diffraction type particle size distribution measuring apparatus (LA-700: made by Horiba Seisakusho). As a measuring method, a sample in a dispersion was adjusted to have a solid content of about 2 g, and ion exchange water was added thereto to make about 40 ml. This was put into the cell until it reached an appropriate concentration, waited for about 2 minutes, and measured when the concentration in the cell became almost stable. The obtained volume average particle diameter for each channel was accumulated from the smaller volume average particle diameter, and the volume average particle diameter was determined to be 50%.

<Radically polymerizable compound>
As the radical polymerizable compound, a radical polymerizable compound having no charge transporting structure may be used alone, a radical polymerizable compound having a charge transporting structure may be used alone, or a combination thereof may be used. May be. When a radically polymerizable compound that does not have a charge transporting structure is used alone as a radically polymerizable compound, a charge transporting material that does not have a radically polymerizable functional group is used in order to support the surface layer with a charge transporting function. It is preferable to do. The term “charge transporting material having no radically polymerizable functional group” as used herein refers to the charge transporting substance described in the section of the charge transporting layer. Moreover, you may add the various additives mentioned later for the purpose of providing another function to a surface layer.

  Examples of the radical polymerizable functional group include 1-substituted ethylene functional groups and 1,1-substituted ethylene functional groups shown below.

(1) Examples of the 1-substituted ethylene functional group include functional groups represented by the following general formula (1).
CH ₂ = ^{CH-X 1} - Formula (1)
In the general formula (1), X ¹ is a phenylene group which may have a substituent, an arylene group, which may have a substituent alkenylene group such as a naphthylene group, -CO- group, - COO— group, —CON (R ¹⁰ ) — group (wherein R ¹⁰ is a hydrogen atom, an alkyl group such as a methyl group or an ethyl group, an aralkyl group such as a benzyl group, a naphthylmethyl group or a phenethyl group, a phenyl group, or a naphthyl group) Represents an aryl group such as a group) or an S-group.
Specific examples of these substituents include vinyl group, styryl group, 2-methyl-1,3-butadienyl group, vinylcarbonyl group, acryloyloxy group, acryloylamide group, vinylthioether group, and the like.

(2) Examples of the 1,1-substituted ethylene functional group include functional groups represented by the following general formula (2).
_{CH 2 = C (Y) -X} 2 - Formula (2)
However, in said general formula (2), Y is an alkyl group which may have a substituent, an aralkyl group which may have a substituent, a phenyl group which may have a substituent, a naphthyl group. An aryl group such as a halogen atom, a cyano group, a nitro group, an alkoxy group such as a methoxy group or an ethoxy group, -COOR ¹¹ group (where R ¹¹ is a hydrogen atom, a methyl group optionally having substituents, Represents an alkyl group such as an ethyl group, an aralkyl group such as an optionally substituted benzyl or phenethyl group, an aryl group such as an optionally substituted phenyl group or naphthyl group), or CONR. ^{12 R} 13 ^(provided that, R ¹² and R ¹³ are hydrogen atoms, which may have a substituent an alkyl group such as methyl group and ethyl group, which may have a substituent group benzyl group, naphthylmethyl group Alternatively aralkyl group, or a substituent a phenyl group which may have a phenetyl group, an aryl group such as a naphthyl group, may be the same or different from each other.
X ² represents the same substituent, single bond, or alkylene group as X ^{1 in the} general formula (1). However, at least one of Y and X ² is an oxycarbonyl group, a cyano group, an alkenylene group, or an aromatic ring.

  Examples of these substituents include an α-acryloyloxy group, a methacryloyloxy group, an α-cyanoethylene group, an α-cyanoacryloyloxy group, an α-cyanophenylene group, and a methacryloylamino group.

Examples of the substituent further substituted on the substituent for X ¹ , X ² , and Y include, for example, an alkyl group such as a halogen atom, a nitro group, a cyano group, a methyl group, and an ethyl group, and an alkoxy group such as a methoxy group and an ethoxy group. Group, aryloxy groups such as phenoxy group, aryl groups such as phenyl group and naphthyl group, aralkyl groups such as benzyl group and phenethyl group, and the like.

  Among these radical polymerizable functional groups, acryloyloxy group and methacryloyloxy group are particularly useful.

<Radically polymerizable compound having no charge transport structure>
The radical polymerizable compound having no charge transporting structure used in the present invention is a hole transporting structure such as triarylamine, hydrazone, pyrazoline, carbazole, such as condensed polycyclic quinone, diphenoquinone, cyano group or nitro group. A compound having no electron transport structure such as an electron-withdrawing aromatic ring having a radical polymerizable functional group. The radical polymerizable functional group is not particularly limited as long as it is the radical polymerizable functional group described above, and a generally known compound can be used.

  In the present invention, the number of functional groups of the radical polymerizable compound is not particularly limited, but in order to give the surface layer wear resistance, at least one radical polymerizable compound having three or more radical polymerizable functional groups is used. It is preferable to use it. When only the monofunctional and bifunctional radically polymerizable compounds are used, the cross-linking bond in the surface layer is so thin that it is difficult to achieve a dramatic improvement in wear resistance. However, when only a trifunctional or higher functional radically polymerizable compound is used, defects such as a decrease in surface smoothness due to an increase in the viscosity of the coating liquid or a crack due to volume shrinkage during the curing reaction may occur. One or more kinds of radically polymerizable compounds and radically polymerizable oligomers are used in combination for the purpose of adjusting the viscosity of the coating liquid, maintaining the surface smoothness of the surface layer, preventing cracks due to crosslinking shrinkage, and reducing the surface free energy. Also good.

<Radically polymerizable compound having a charge transporting structure>
Examples of the radically polymerizable compound having a charge transporting structure used in the present invention include hole transporting structures such as triarylamine, hydrazone, pyrazoline, and carbazole, such as condensed polycyclic quinone, diphenoquinone, cyano group, and nitro group. It refers to a compound having an electron transport structure such as an electron-withdrawing aromatic ring and having a radical polymerizable functional group. The radical polymerizable functional group is not particularly limited as long as it is the radical polymerizable functional group described above.

  In the present invention, the number of functional groups of the radical polymerizable compound is not particularly limited, but the number of radical polymerizable functional groups is preferably 1 in order to have good electrical characteristics over a long period of time. When a bifunctional or higher functional charge transporting compound is used as the main component, the site having the charge transporting structure is fixed in the cross-linked structure by a plurality of bonds, so that the intermediate structure (cation radical) at the time of charge transport is It cannot be maintained stably, and the sensitivity is lowered due to charge trapping, and the residual potential is likely to increase. Such deterioration of the electrical characteristics may appear as a phenomenon such as a decrease in image density and thinning of characters.

  As the charge transport structure, a triarylamine structure is highly effective. Furthermore, when a compound represented by the structure of the following general formula (I) or (II) is used, electrical characteristics such as sensitivity and residual potential are favorably maintained.

In the general formulas (I) and (II), R ₁₀ is a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a cyano group, A nitro group, an alkoxy group, —COOR ₁₁ (wherein R ₁₁ represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted aryl group), a carbonyl halide CONR ₁₂ R ₁₃ (wherein R ₁₂ and R ₁₃ may be the same or different from each other, and may be a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted group) Represents an aralkyl group or a substituted or unsubstituted aryl group. Ar ₁ and Ar ₂ may be the same as or different from each other, and represent a substituted or unsubstituted arylene group. Ar ₃ and Ar ₄ may be the same as or different from each other, and represent a substituted or unsubstituted aryl group. X ₁₀ represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group. Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether group, or an alkyleneoxycarbonyl group. m and n both represent an integer of 0 to 3. As specific compounds represented by these general formulas (I) and (II), those exemplified in Japanese Patent No. 4145820, Japanese Patent No. 418839 and the like can be used.

  The radical polymerizable compound having a charge transport structure used in the present invention is important for imparting charge transport performance to the surface layer, and this component is preferably 20% by mass to 80% by mass with respect to the total amount of the surface layer. A mass% to 70 mass% is more preferable. When the radically polymerizable compound having the charge transporting structure is less than 20% by mass, the charge transporting performance of the surface layer cannot be sufficiently maintained, and the electrical properties such as sensitivity reduction and residual potential increase are deteriorated by repeated use. When the content exceeds 80% by mass, the content of the radically polymerizable compound having no charge transport structure represented by the general formula (1) decreases, resulting in a decrease in the crosslink density and high wear resistance. Is not demonstrated. Although the electrical characteristics and abrasion resistance required differ depending on the process used, it cannot be said unconditionally, but the range of 30% by mass to 70% by mass is particularly preferable in consideration of the balance of both characteristics. In addition, when used in combination with a charge transporting material having no radical polymerizable functional group, which will be described later, the charge transporting material having no radical polymerizable functional group is used in an amount of 20 to 80% by weight based on the total amount of the surface layer. Is preferable, and 30 mass%-70 mass% is more preferable.

<Charge transporting material having no radically polymerizable functional group>
A charge transporting material having no radically polymerizable functional group is a hole transporting structure such as triarylamine, hydrazone, pyrazoline, and carbazole, for example, electron withdrawing having a condensed polycyclic quinone, diphenoquinone, a cyano group, or a nitro group. It refers to a compound having an electron transport structure such as an aromatic ring and having no radically polymerizable functional group.

  Examples of the electron transporting material include chloroanil, bromanyl, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4 , 5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-tri Examples thereof include electron-accepting substances such as nitrodibenzothiophene-5,5-dioxide and diphenoquinone derivatives. These electron transport materials can be used alone or as a mixture of two or more.

  Examples of the hole transport material include poly-N-vinylcarbazole and derivatives thereof, poly-γ-carbazolylethyl glutamate and derivatives thereof, pyrene-formaldehyde condensates and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, polysilane, oxazole derivatives, Oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazolines Derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, bisstilbene derivatives, enamine derivatives, etc. Other known materials may be used.

  These charge transport materials may be used alone or in combination of two or more. Further, as described above, it may be used in combination with a radical polymerizable compound having a charge transporting structure. The material having such a charge transporting structure is preferably 20 to 80% by mass, more preferably 30 to 70% by mass with respect to the total mass of the surface layer.

<Radical radical polymerization initiator>
There is no restriction | limiting in particular as radical photopolymerization initiator, The compound used generally can be used. In addition, in order to perform radical polymerization efficiently, you may use a thermal-polymerization initiator together. The content of the photo radical polymerization initiator is preferably 0.5 part by mass to 40 parts by mass, and more preferably 1 part by mass to 20 parts by mass with respect to 100 parts by mass of the radical polymerizable compound.

  Specific examples of the photo radical polymerization initiator include, for example, diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 4- (2-hydroxy Ethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1,2-hydroxy-2-methyl-1-phenylpropane- Acetophenones or ketals such as 1-one, 2-methyl-2-morpholino (4-methylthiophenyl) propan-1-one, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime Photopolymerization initiator: benzoin, benzoin methyl ether, benzoin ethyl ether, ben Benzoin ether photopolymerization initiators such as inisobutyl ether and benzoin isopropyl ether; benzophenone, 4-hydroxybenzophenone, methyl o-benzoylbenzoate, 2-benzoylnaphthalene, 4-benzoylbiphenyl, 4-benzoylphenyl ether, acrylated benzophenone Benzophenone photopolymerization initiators such as 1,4-benzoylbenzene; thioxanthone series such as 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone Photopolymerization initiator; bis (cyclopentadienyl) -di-chloro-titanium, bis (cyclopentadienyl) -di-phenyl-titanium, bis (cyclopentadienyl) Titanocene light such as bis (2,3,4,5,6 pentafluorophenyl) titanium, bis (cyclopentadienyl) -bis (2,6-difluoro-3- (pyrrol-1-yl) phenyl) titanium Polymerization initiator; Other photopolymerization initiators include ethyl anthraquinone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, bis (2,4,6-trimethyl) Benzoyl) phenylphosphine oxide, bis (2,4-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, methylphenylglyoxyester, 9,10-phenanthrene, acridine compound, triazine compound, imidazole compound ,etc Can be mentioned. Moreover, what has a photopolymerization acceleration effect can also be used individually or in combination with the said photoinitiator. Examples include triethanolamine, methyldiethanolamine, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, (2-dimethylamino) ethyl benzoate, 4,4'-dimethylaminobenzophenone, and the like.

Examples of the thermal polymerization initiator include 2,5-dimethylhexane-2,5-dihydroperoxide, dicumyl peroxide, benzoyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5- Peroxide initiators such as di (peroxybenzoyl) hexyne-3, di-t-butyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, lauroyl peroxide; azobisisobutylnitrile, azobiscyclohexane And azo initiators such as carbonitrile, methyl azobisisobutyrate, azobisisobutylamidine hydrochloride, 4,4′-azobis-4-cyanovaleric acid, and the like.
These polymerization initiators may be used alone or in combination of two or more.

<Surface layer configuration>
As described above, the surface layer of the present invention comprises at least a radical polymerizable compound and a photo radical polymerization initiator, and is formed by polymerization by means of light energy irradiation means, and comprises at least a fluororesin and an inorganic material. The organic-inorganic composite fine particles are included.

(Amount of organic / inorganic composite fine particles in the surface layer of the electrophotographic photoreceptor)
The blending amount of the organic / inorganic composite fine particles in the surface layer of the electrophotographic photosensitive member is preferably 5 vol% or more and 40 vol% or less, and further, the fluororesin is exposed on the surface layer surface so as to be within the scope of the present invention. Preferably it is. When the compounding amount of the organic / inorganic composite fine particles is less than 5 vol%, the ratio of the fluororesin exposed on the surface layer surface becomes small, and the effect of reducing the frictional resistance between the electrophotographic photosensitive member surface and the cleaning blade is sufficiently obtained. This is not preferable because it cannot be performed. In addition, when the compounding amount of the organic / inorganic composite fine particles exceeds 40 vol%, the charge transport component occupying the surface layer is reduced, and the charge transport function that should be possessed as an electrophotographic photosensitive member is impaired. Insufficient binder component to maintain the surface is not preferable because the organic-inorganic composite fine particles are easily lost by rubbing such as blade cleaning, resulting in a decrease in wear durability.

(Preferred surface structure)
In the present invention, it is extremely important that the lubrication product (fluorine resin in the present invention) is exposed on the outermost surface of the electrophotographic photosensitive member. (Exposed shape) is important for reducing the frictional resistance between the surface of the electrophotographic photosensitive member and the cleaning blade. When the organic-inorganic composite fine particles are dispersed in the surface layer of the electrophotographic photosensitive member, the present inventor makes “a certain amount of fluororesin exposure on the surface of the electrophotographic photosensitive member” “uniformly on the surface of the electrophotographic photosensitive member”. Has been found to be effective in reducing the frictional resistance with the cleaning blade.

  Regarding the exposure amount of the fluororesin on the surface of the electrophotographic photosensitive member, it refers to the exposure of the fluororesin contained in the organic-inorganic composite fine particles to the surface of the electrophotographic photosensitive member. 5% to 50%, preferably 10% to 40%. Further, the exposed shape varies depending on the composite form of the organic / inorganic composite fine particles to be applied, and thus cannot be defined unconditionally, but is not particularly limited as long as the fluororesin is uniformly exposed over the entire surface layer of the electrophotographic photosensitive member. .

  The uniform exposure of the fluororesin on the surface of the electrophotographic photosensitive member is difficult to define, but here, it is divided into three in the width direction of the electrophotographic photosensitive member, and a total of 15 points (figure 15 in the outer peripheral direction at the center position) 4) is observed by the following observation method (observation method of organic-inorganic composite fine particles), and the proportion of the fluororesin in the surface layer is 5% or more and 50% or less at any observation location, and the area The coefficient of variation of the ratio is preferably 0.10 or less.

(Observation method of organic-inorganic composite fine particles)
A method for quantifying the content ratio of the inorganic fine particles contained in the organic-inorganic composite fine particles and the ratio of the fluororesin in the surface of the electrophotographic photosensitive member is not particularly limited as long as elemental analysis and mapping thereof are possible. Here, a method using an energy dispersive X-ray detector / scanning electron microscope (EDS-SEM) will be described as an example of a quantitative method. The EDS-SEM scans the object to be observed with a finely focused electron beam and detects the amount of secondary electrons emitted to observe the object surface image in detail (generally 50 to 300,000 times). At the same time, by detecting characteristic X-rays generated by electron beam irradiation, it is an apparatus that analyzes the element ratio of a minute region on the surface, maps a specific element, and the like.

(Observation of organic-inorganic composite fine particles)
By observing the organic / inorganic composite fine particles, the ratio of the inorganic material to the organic / inorganic composite fine particles can be quantified. When the organic / inorganic composite fine particles have a relatively large particle size, two-dimensional element distribution information is obtained by element mapping, and the area ratio is converted into a volume ratio (3/2 of the area ratio) to obtain organic / inorganic The ratio of the inorganic material to the composite fine particles can be obtained. In addition, when the organic / inorganic composite fine particles have a small particle size or the resolution of the EDS-SEM used is insufficient, the organic / inorganic composite fine particles to be observed are irradiated with an electron beam, and the element ratio based on the obtained characteristic X-ray intensity. It is possible to determine the ratio of the inorganic material in the organic / inorganic composite fine particles based on the organic / inorganic material blending ratio calibration curve.

(Observation of cross section of electrophotographic photoreceptor)
By observing the cross section of the electrophotographic photosensitive member, the proportion of the organic-inorganic composite fine particles contained in the surface layer can be quantified. First, the cross-sectional structure of the electrophotographic photosensitive member is exposed by a commonly used method such as a microtome or FIB, and then the fluorine atoms on the cross-sectional surface of the electrophotographic photosensitive member and the constituent elements of the inorganic material are mapped by the above-described method. Then, the area ratio occupied by the organic-inorganic composite fine particles in the observation cross section is obtained by dividing the inorganic material constituent element detection area by the observation area. Subsequently, the ratio which occupies for the surface layer of this organic-inorganic composite fine particle can be obtained by converting the area ratio into a volume ratio (3/2 of the area ratio).

(Observation of electrophotographic photoreceptor surface)
By observing the surface of the electrophotographic photosensitive member, the ratio of the fluororesin contained in the organic-inorganic composite fine particles to the surface of the electrophotographic photosensitive member can be quantified. The fluorine atom mapping of the observation location determined by the method described above is performed, and the ratio of the exposed area of the fluororesin to the surface of the electrophotographic photosensitive member at the observation location is calculated from the fluorine atom detection area / observation area. At this time, when element mapping of the electrophotographic photosensitive member is performed with an excessive acceleration voltage, not only the state of the outermost surface of the photosensitive member but also information in the vicinity of the surface may be obtained. Evaluation at an appropriate acceleration voltage is important.

<Other fillers added>
In addition to the organic-inorganic composite fine particles, the surface layer can contain filler particles for the purpose of improving wear resistance. The filler particles may be any generally known inorganic particles such as titanium oxide, tin oxide, zinc oxide, zirconium oxide, indium oxide, antimony oxide, boron nitride, silicon nitride, calcium oxide, barium sulfate, ITO, silica, colloidal silica. And alumina.

  The average primary particle size of these filler fine particles is preferably 0.01 to 0.5 μm from the viewpoint of light transmittance and wear resistance of the surface layer. When the average primary particle size of the filler is less than 0.01 μm, it causes a decrease in dispersibility and the effect of improving the wear resistance is not sufficiently exhibited. When the average primary particle size exceeds 0.5 μm, the specific gravity of the filler particles However, there may be a problem with the life of the coating solution, such as promoting the sedimentation of the filler in the dispersion.

  The higher the filler particle concentration in the surface layer is, the better the wear resistance is. However, if it is too high, the charge transport function and wear resistance are reduced as in the case of the organic-inorganic composite fine particles described above. Because it causes, it is not preferable. Therefore, when adding filler particles, it is preferable to determine the amount of the organic-inorganic composite fine particles in consideration. Although depending on the blending amount of the organic / inorganic composite fine particles, good wear resistance can be expected when the proportion of the filler particles in the surface layer is about 10 vol% to 40 vol%.

<Distribution method>
As a method for dispersing the organic / inorganic composite fine particles and filler particles in the surface layer, it is preferable to disperse the organic inorganic composite fine particles and filler particles by a dispersion method generally used in a surface layer coating liquid described later. Examples of the dispersion method include a ball mill, a sand mill, a KD mill, a three-roll mill, a pressure homogenizer, and ultrasonic dispersion.

(Dispersant)
When the organic / inorganic composite fine particles and filler particles are dispersed in the surface layer, it can be surface-treated with a dispersant or a surfactant, which is preferable from the viewpoint of dispersibility. When the dispersibility of the organic-inorganic composite fine particles is insufficient, not only the effect of reducing the frictional resistance between the surface of the electrophotographic photosensitive member and the cleaning blade, which is the greatest effect in the present invention, is reduced, but also the electrophotographic photosensitive member In order to cause a decrease in charge transport property, charge retention, etc. that should be inherent, and decrease in transparency of the coating film and generation of coating film defects, it is preferable to take good measures to give good dispersibility. . Furthermore, as described above, the absence of aggregated particles from the surface layer forms large surface irregularities, and also causes poor toner cleaning and reduced wear resistance of the electrophotographic photosensitive member. There is a possibility that it will be a major factor that hinders the transformation.

As the dispersant and surfactant, the above-described commonly used dispersants and surfactants can be used, but those that can maintain the insulating properties of the organic-inorganic composite fine particles and filler particles are preferable.
The surface treatment amount varies depending on the average primary particle size of the lubricating fine particles (organic / inorganic composite fine particles) to be used, but is preferably 3 to 30% by mass, more preferably 5 to 20% by mass with respect to the mass of the lubricating fine particles. . When the amount of the dispersant and the surfactant is less than this, the effect of dispersing the filler cannot be obtained, and when the amount is too large, the residual potential is remarkably increased. These surface treatment agents may be used alone or in combination of two or more.

<Other additives>
Furthermore, the surface layer forming coating liquid of the present invention may contain additives such as various plasticizers (for the purpose of stress relaxation and adhesion improvement), leveling agents, and low molecular charge transport materials having no radical reactivity as required. Can be contained. As these additives, known additives can be used, and as plasticizers, those used in general resins such as dibutyl phthalate and dioctyl phthalate can be used, and the amount used is the total solid content of the coating liquid. 20 parts by weight or less, preferably 10 parts by weight or less. In addition, as leveling agents, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers or oligomers having a perfluoroalkyl group in the side chain, and the amount used can be the total solid content of the coating liquid. 3 parts by weight or less is appropriate.

<Formation of surface layer>
The surface layer of the present invention is formed by applying and curing a coating liquid containing at least the aforementioned radical polymerizable compound, a photo radical polymerization initiator, and organic-inorganic composite fine particles on the photosensitive layer described later. The When the radically polymerizable compound is a liquid, the coating liquid used for coating can be coated by dissolving other components in the liquid. However, if necessary, the coating liquid is diluted with a solvent and coated. The solvent used here is not particularly limited as long as it is usually used. For example, alcohols such as methanol, ethanol, propanol and butanol, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, esters such as ethyl acetate and butyl acetate, ethers such as tetrahydrofuran, dioxane and propyl ether, dichloromethane And halogen series such as dichloroethane, trichloroethane and chlorobenzene, aromatic series such as benzene, toluene and xylene, and cellosolv series such as methyl cellosolve, ethyl cellosolve and cellosolve acetate. These solvents may be used alone or in combination of two or more.

  The coating method used for forming the surface layer is not particularly limited as long as it is a commonly used coating method. A coating method may be appropriately selected depending on the viscosity of the coating liquid, the desired surface layer thickness, and the like. Examples include dip coating, spray coating, bead coating, ring coating, and the like.

In this invention, after apply | coating this coating liquid, a surface layer is hardened by giving energy from the outside. As the external energy used at this time, optical energy is mainly used, but thermal energy may be used in combination.
As the light energy, a light source such as an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a xenon arc metal halide lamp or the like may be used. It is preferable to select in consideration of the absorption characteristics of a monofunctional radically polymerizable compound having a charge transporting structure and a photopolymerization initiator used in combination. The emission intensity of light source used, it is preferable generally is exposed with 365nm illumination of 50mW ^/ cm ² ~2000mW ^/ cm 2 and wavelength as a reference. Moreover, when the illuminance measurement in the vicinity of the maximum emission wavelength is possible, it is more preferable to expose in the illuminance range. When the illuminance is low, the time required for curing increases, which is not preferable from the viewpoint of productivity. On the other hand, when the illuminance is high, curing shrinkage is likely to occur, and the surface may have a skin-like defect or crack, or may peel at the interface with the adjacent layer.

  During UV irradiation, the temperature of the photoreceptor surface layer rises due to the influence of heat rays generated from the light source. If the surface temperature of the photoconductor rises too much, curing shrinkage of the surface layer is likely to occur, and low molecular components contained in the adjacent layer migrate to the surface layer, resulting in inhibition of curing or as an electrophotographic photoconductor. This is not preferable, for example, because the electrical characteristics are degraded. Therefore, the photoreceptor surface temperature during UV irradiation is 100 ° C. or less, preferably 80 ° C. or less. As a cooling method, it is possible to use a cooling agent sealed inside the photoconductor, cooling with a gas or liquid inside the photoconductor, or the like.

  As the thermal energy, air, nitrogen or other gas, steam, various heat media, infrared rays, or electromagnetic waves can be used, and heating is performed from the coating surface side or the support side. The heating temperature is preferably 100 ° C. or higher and 170 ° C. or lower. When the temperature is lower than 100 ° C., the reaction rate is slow, so that productivity is lowered and unreacted material remains in the film. On the other hand, when the treatment is performed at a temperature higher than 170 ° C., the shrinkage of the film due to the cross-linking is increased, and the skin-like defects and cracks may be generated on the surface, or peeling may occur at the interface with the adjacent layer. Further, when the volatile component in the photosensitive layer is sprayed to the outside, it is not preferable because desired electrical characteristics may not be obtained. When using a resin having a large shrinkage due to crosslinking, it is also effective to complete the crosslinking at a high temperature of 100 ° C. or higher after preliminary crosslinking at a low temperature of less than 100 ° C.

  You may post-heat with respect to the surface layer after hardening as needed. For example, in the case where a large amount of residual solvent remains in the film, it may cause a decrease in electrical characteristics or deterioration with time. Therefore, it is preferable to volatilize the residual solvent by post-heating.

  The film thickness of the surface layer is preferably 1 to 15 μm or less, preferably 3 to 10 μm from the viewpoint of protecting the photosensitive layer. When the surface layer is thin, not only the photosensitive layer cannot be protected from mechanical abrasion due to the contact member to the photosensitive member or proximity discharge by a charger, etc., but also the film surface becomes difficult to level during film formation. It may be crumpled. On the other hand, when the surface layer is thick, the entire photoreceptor layer becomes thick, and the reproducibility of the image due to the diffusion of charges is not preferable.

  The surface layer preferably has an elastic power of 40% or more, more preferably 40 to 60%. If the elastic power is less than 40%, the concentration of the pressing force accompanying toner aggregation during transfer tends to generate a rubbing force, which tends to cause surface scraping and scratches. This elastic power can be obtained by providing a crosslinked surface layer having a sufficient crosslinked structure.

<Adhesive layer>
Note that an adhesive layer may be provided between both layers as necessary for the purpose of preventing delamination due to poor adhesion between the surface layer / photosensitive layer.
As the adhesive layer, the radical polymerizable compound may be used, or a non-crosslinked polymer compound may be used. Non-crosslinked polymer compounds include polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, polyacrylamide, and polyvinyl benzal. , Polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, polyvinyl pyrrolidone, and the like, but are not limited thereto. Further, the radical polymerizable compound and the non-crosslinked polymer compound may be used alone or in a mixture of two or more. Furthermore, a radical polymerizable compound and a non-crosslinked polymer compound may be used in combination as long as sufficient adhesiveness is obtained. Of course, the charge transport material described in the present specification may be used or used in combination. Moreover, an additive may be used as appropriate for the purpose of improving the adhesiveness.

  The adhesive layer is formed by applying a coating solution prepared by dissolving or dispersing a compound formulated in a prescribed formulation in a solvent such as tetrahydrofuran, dioxane, dichloroethane, or cyclohexane by dip coating, spray coating, bead coating, or ring coating. it can. The thickness of the adhesive layer is suitably about 0.1 to 5 μm, preferably 0.1 to 3 μm is most suitable.

[Image Forming Method and Image Forming Apparatus]
The image forming apparatus of the present invention comprises at least an electrophotographic photosensitive member, a charging unit, an exposure unit, a developing unit, and a transfer unit, and other units appropriately selected as necessary, for example, The image forming apparatus includes a fixing unit, a cleaning unit, a charge eliminating unit, a recycling unit, a control unit, and the like. The electrophotographic photosensitive member here is the electrophotographic photosensitive member of the present invention.

The image forming method used in the present invention includes at least a charging step, an exposure step, a development step, and a transfer step, and further other steps appropriately selected as necessary, for example, a fixing step, a cleaning step, and a static elimination step. Process, recycling process, control process, etc.
The image forming method used in the present invention can be preferably implemented by the image forming apparatus of the present invention, the charging step can be performed by the charging unit, and the exposure step can be performed by the exposing unit. The developing step can be performed by the developing unit, the transferring step can be performed by the transferring unit, the fixing step can be performed by the fixing unit, and the cleaning step can be performed by the cleaning unit. The other steps can be performed by the other means.

(Charging process and charging means)
The charging step is a step of charging the surface of the electrophotographic photosensitive member, and is performed by the charging unit.
The charging means is not particularly limited as long as it can uniformly apply a voltage to the surface of the electrophotographic photosensitive member, and can be appropriately selected depending on the purpose. A non-contact charging means for charging the photoconductor in a non-contact manner is used.

As the non-contact charging means, for example, a non-contact charger using a corona discharge, a needle electrode device, a solid discharge element; conductive or semiconductive disposed with a minute gap with respect to the electrophotographic photosensitive member And a charging roller. Among these, corona discharge is particularly preferable.
The corona discharge is a non-contact charging method that gives positive or negative ions generated by corona discharge in the air to the surface of the electrophotographic photosensitive member, and has a characteristic of giving a certain amount of charge to the electrophotographic photosensitive member. There are a charger and a scorotron charger having a characteristic of giving a constant potential.
The coroton charger is composed of a casing electrode that occupies a half space around the discharge wire, and a discharge wire placed almost at the center thereof.
The scorotron charger is obtained by adding a grid electrode to the corotron charger, and the grid electrode is provided at a position 1.0 mm to 2.0 mm away from the surface of the electrophotographic photosensitive member.

(Exposure process and exposure means)
The exposure can be performed, for example, by exposing the surface of the electrophotographic photosensitive member imagewise using the exposure unit.
The optical system in the exposure is roughly classified into an analog optical system and a digital optical system. The analog optical system is an optical system that directly projects an original onto an electrophotographic photosensitive member by an optical system, and the digital optical system receives image information as an electrical signal, converts this into an optical signal, and converts it into an electrophotographic image. It is an optical system that exposes a photoreceptor to form an image.

The exposure unit is not particularly limited as long as the surface of the electrophotographic photosensitive member charged by the charging unit can be exposed like an image to be formed, and can be appropriately selected according to the purpose. However, various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, a liquid crystal shutter optical system, and an LED optical system can be used.
In the present invention, an optical backside system that performs imagewise exposure from the backside of the electrophotographic photosensitive member may be employed.

(Development process and development means)
The developing step is a step of developing the electrostatic latent image using a toner or a developer to form a visible image.
The visible image can be formed, for example, by developing the electrostatic latent image using the toner or the developer, and can be performed by the developing unit.
The developing unit is not particularly limited as long as it can be developed using, for example, the toner or the developer, and can be appropriately selected from known ones. For example, the toner or developer is accommodated. Preferred examples include those having at least a developing unit capable of bringing the toner or developer into contact or non-contact with the electrostatic latent image.
The developing unit may be a dry developing type, a wet developing type, a single color developing unit, or a multi-color developing unit. For example, a toner having a stirrer for charging the toner or the developer by frictional stirring and a rotatable magnet roller is preferable.

  In the developing device, for example, the toner and the carrier are mixed and agitated, and the toner is charged by friction at that time, and held on the surface of the rotating magnet roller in a raised state to form a magnetic brush. . Since the magnet roller is disposed in the vicinity of the electrophotographic photosensitive member (photosensitive member), a part of the toner constituting the magnetic brush formed on the surface of the magnet roller is caused by an electric attractive force. It moves to the surface of the electrophotographic photoreceptor. As a result, the electrostatic latent image is developed with the toner, and a visible image is formed with the toner on the surface of the electrophotographic photosensitive member.

  The developer accommodated in the developing device is a developer containing the toner, but the developer may be a one-component developer or a two-component developer.

(Transfer process and transfer means)
The transfer step is a step of transferring the visible image onto a recording medium. After the primary transfer of the visible image onto the intermediate transfer member using an intermediate transfer member, the visible image is transferred onto the recording medium. A primary transfer step of forming a composite transfer image by transferring a visible image onto an intermediate transfer body using two or more colors, preferably a full color toner, as the toner, and a composite transfer image; A mode including a secondary transfer step of transferring the transfer image onto the recording medium is more preferable.
The transfer can be performed, for example, by charging the electrophotographic photosensitive member with the transfer charger using the visible image, and can be performed by the transfer unit. The transfer means includes a primary transfer means for transferring a visible image onto an intermediate transfer member to form a composite transfer image, and a secondary transfer means for transferring the composite transfer image onto a recording medium. Embodiments are preferred.
The intermediate transfer member is not particularly limited and may be appropriately selected from known transfer members according to the purpose. For example, a transfer belt and the like are preferable.

  The transfer unit (the primary transfer unit and the secondary transfer unit) includes at least a transfer unit that peels and charges the visible image formed on the electrophotographic photosensitive member toward the recording medium. preferable. There may be one transfer means or two or more transfer means. Examples of the transfer device include a corona transfer device using corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device.

  The recording medium is typically plain paper, but is not particularly limited as long as it can transfer an unfixed image after development, and can be appropriately selected according to the purpose. PET for OHP A base or the like can also be used.

(Fixing process and fixing means)
The fixing step is a step of fixing the visible image transferred to the recording medium using a fixing device, and may be performed each time the toner of each color is transferred to the recording medium, or for the toner of each color. You may perform this simultaneously in the state which laminated | stacked this.
The fixing unit is not particularly limited and may be appropriately selected depending on the intended purpose. A fixing unit and a heat source for heating the fixing member are used.
Examples of the fixing member include a combination of an endless belt and a roller, a combination of a roller and a roller, etc., but the warm-up time can be shortened, and in terms of realizing energy saving, A combination of an endless belt and a roller having a small heat capacity is preferable in terms of expansion of the fixable width.

(Cleaning process and cleaning means)
The cleaning step is a step of removing the toner remaining on the electrophotographic photosensitive member, and can be suitably performed by a cleaning unit. In addition, it is also possible to employ a method in which the charge of the residual toner is made uniform by the rubbing member and collected by the developing roller without using the cleaning means.
The cleaning means is not particularly limited, and may be selected from known cleaners as long as the electrophotographic toner remaining on the electrophotographic photosensitive member can be removed. For example, a magnetic brush cleaner Suitable examples include electrostatic brush cleaners, magnetic roller cleaners, blade cleaners, brush cleaners, web cleaners, and the like.

(Static elimination process and static elimination means)
The neutralization step is a step of performing neutralization by applying a neutralization bias to the electrophotographic photosensitive member, and can be suitably performed by a neutralization unit.
The neutralizing means is not particularly limited and may be appropriately selected from known neutralizers as long as it can apply a neutralizing bias to the electrophotographic photosensitive member. For example, a neutralizing lamp is preferably used. Can be mentioned.

(Recycling process and recycling means)
The recycling step is a step of recycling the toner removed by the cleaning step to the developing unit, and can be suitably performed by the recycling unit. There is no restriction | limiting in particular as said recycling means, A well-known conveyance means etc. are mentioned.

(Control process and control means)
The control step is a step of controlling each of the steps, and can be suitably performed by a control unit.
The control means is not particularly limited as long as the movement of each means can be controlled, and can be appropriately selected according to the purpose. Examples thereof include devices such as a sequencer and a computer.

Next, the image forming apparatus and the process cartridge of the present invention will be described in detail with reference to the drawings.
The image forming apparatus of the present invention uses the electrophotographic photosensitive member of the present invention. For example, at least after the photosensitive member is charged, exposed to an image, and developed, the toner image is transferred to an image holding member (transfer paper). And fixing and cleaning the surface of the photoreceptor.
In some cases, an image forming apparatus that directly transfers an electrostatic latent image to a recording medium and develops it does not necessarily have the above-described process disposed on a photoconductor.

  FIG. 8 is a schematic diagram illustrating an example of an image forming apparatus. A charging charger 3 is used as a means for charging the photosensitive member on average. As the charging means, a corotron device, a scorotron device, a solid discharge element, a needle electrode device, a roller charging device, a conductive brush device, or the like is used, and a known system can be used.

  Next, the image exposure unit 5 is used to form an electrostatic latent image on the uniformly charged photoreceptor 1. As the light source, all luminescent materials such as a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), and an electroluminescence (EL) can be used. Various types of filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range.

  Next, the developing unit 6 is used to visualize the electrostatic latent image formed on the photoreceptor 1. Development methods include a one-component development method using a dry toner, a two-component development method, and a wet development method using a wet toner. When the photosensitive member is positively (negatively) charged and image exposure is performed, a positive (negative) electrostatic latent image is formed on the surface of the photosensitive member. A positive image can be obtained by developing this with negative (positive) toner (electrodetection fine particles), and a negative image can be obtained by developing with positive (negative) toner.

  Next, a transfer charger 10 is used to transfer the toner image visualized on the photoreceptor 1 onto the recording medium 9. In addition, a pre-transfer charger 7 may be used for better transfer. As these transfer means, a transfer charger, an electrostatic transfer method using a bias roller, a mechanical transfer method such as an adhesive transfer method and a pressure transfer method, and a magnetic transfer method can be used. As the electrostatic transfer method, the charging means can be used.

  Next, a separation charger 11 and a separation claw 12 are used as means for separating the recording medium 9 from the photoreceptor 1. As other separation means, electrostatic adsorption induction separation, side end belt separation, tip grip conveyance, curvature separation, and the like are used. As the separation charger 11, the charging means can be used.

  Next, a fur brush 14 and a cleaning blade 15 are used to clean the toner remaining on the photoconductor after transfer. Further, a pre-cleaning charger 13 may be used in order to perform cleaning more efficiently. Other cleaning means include a web method, a magnet brush method, and the like, but each may be used alone or in combination.

  Further, a charge eliminating unit is used for the purpose of removing the latent image on the photosensitive member as necessary. As the charge removal means, the charge removal lamp 2 and the charge removal charger are used, and the exposure light source and the charging means can be used respectively.

  In addition, known processes can be used for reading, feeding, fixing, paper discharge and the like that are not close to the photoconductor.

The present invention is an image forming method and an image forming apparatus using the electrophotographic photoreceptor according to the present invention for such image forming means.
The image forming means may be fixedly incorporated in a copying apparatus, facsimile, or printer, but may be incorporated in these apparatuses in the form of a process cartridge and detachable. An example of the process cartridge is shown in FIG.
The process cartridge includes a photosensitive member 101, and further includes at least one of a charging unit 102, a developing unit 104, a transfer unit 106, a cleaning unit 107, and a charge eliminating unit (not shown). It is a device (part) that is detachable.

  Referring to the image forming process using the process cartridge of FIG. 9, the photosensitive member 101 is charged in the direction of the arrow while being charged by the charging unit 102 and exposed by the exposure unit 103, and the electrostatic latent image corresponding to the exposed image on the surface thereof. The electrostatic latent image is developed with toner by the developing unit 104, and the toner development is transferred to the recording medium 105 by the transfer unit 106 and printed out. Next, the surface of the photoconductor after the image transfer is cleaned by the cleaning unit 107 and further neutralized by a neutralizing unit (not shown), and the above operation is repeated again.

  The image forming method, the image forming apparatus, and the process cartridge of the present invention use the electrophotographic photosensitive member of the present invention having an intermediate layer made of an amorphous oxide semiconductor. Thus, it is possible to continuously obtain high-quality images with few defects and extremely low electrophotographic characteristics.

  EXAMPLES Next, although an Example demonstrates this invention in detail, this invention is not limited to a following example.

<< Preparation of organic-inorganic composite fine particles >>
・ Organic inorganic composite fine particles 1:
Into a stainless steel container (3 L) equipped with a stirrer and equipped with a temperature adjusting device, 666 g of silica fine particle aqueous dispersion (AEROSIL130 (manufactured by EVONIK), true specific gravity 2.05, primary particle size 16 nm, solid content 3 wt%) is charged. Was adjusted to 21 ° C. ± 1 ° C., and stirred using a stirrer at a rotational speed of 400 rpm. Next, 600 g of an emulsion-polymerized PTFE aqueous dispersion adjusted to a solid content of 30 wt% (true specific gravity 2.12, perfluorooctanoic acid as a dispersant) was gently added, and a coagulant (3%) after 5 minutes from the completion of the addition. 4 g of aluminum nitrate aqueous solution) is added, and 30 mL of 1,1-dichloro-1-fluoroethane is further added after 3 minutes to form composite fine particles of PTFE and silica. Thereafter, the obtained composite fine particles were filtered through a 2000 mesh stainless steel wire mesh, dehydrated and dried at 150 ° C. for 20 hours to obtain a dry powder. The PTFE / silica composite fine particles (organic / inorganic composite fine particles 1) obtained by this method had a volume average particle size of 1.27 μm and a volume ratio of the inorganic material of 10.3 vol%.

-Organic inorganic composite fine particles 2;
The organic / inorganic composite fine particles 1 were prepared in the same manner as the organic / inorganic composite fine particles 1 except that the blending amounts of the silica fine particle aqueous dispersion and the emulsion polymerization PTFE aqueous dispersion were 666 g and 266 g, respectively. did. The PTFE / silica composite fine particles (organic / inorganic composite fine particles 2) obtained by this method had a volume average particle size of 1.09 μm and a volume ratio of the inorganic material of 20.5 vol%.

・ Organic inorganic composite fine particles 3:
In the preparation method of the organic / inorganic composite fine particles 1, the addition amount of the coagulant (3% aluminum nitrate aqueous solution) was 5 g, and 5 minutes later, 35 mL of 1-dichloro-1-fluoroethane was added. Organic-inorganic composite fine particles were produced in the same manner. The PTFE / silica composite fine particles (organic / inorganic composite fine particles 3) obtained by this method had a volume average particle size of 4.21 μm and a volume ratio of the inorganic material of 10.1 vol%.

・ Organic inorganic composite fine particles 4:
The organic / inorganic composite fine particles 1 were prepared in the same manner as the organic / inorganic composite fine particles 1 except that the compounding amounts of the silica fine particle aqueous dispersion and the emulsion polymerization PTFE aqueous dispersion were 100 g and 490 g, respectively. did. The PTFE / silica composite fine particles (organic-inorganic composite fine particles 4) obtained by this method had a volume average particle size of 1.32 μm and a volume ratio of inorganic material of 2.1 vol%.

-Organic inorganic composite fine particles 5;
Organic-inorganic composite fine particles were prepared in the same manner as in organic-inorganic composite fine particles 1 except that the blending amounts of the silica fine particle aqueous dispersion and the emulsion polymerization PTFE aqueous dispersion were 1000 g and 100 g, respectively, in the method for preparing organic-inorganic composite fine particles 1. . The PTFE / silica composite fine particles (organic / inorganic composite fine particles 5) obtained by this method had a volume average particle size of 0.93 μm and a volume ratio of the inorganic material of 50.8 vol%.

  Next, an electrophotographic photosensitive member according to the present invention was produced using the organic-inorganic composite fine particles.

[Example 1]
By coating and drying an intermediate layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution of the following composition on a φ30 mm aluminum cylinder in sequence, an undercoat layer of 3.5 μm thickness A charge generation layer having a thickness of 0.2 μm and a charge transport layer having a thickness of 18 μm were formed.

<Intermediate layer coating solution>
-Alkyd resin 6 parts by mass (Beckosol 1307-60-EL, manufactured by Dainippon Ink & Chemicals, Inc.)
Melamine resin 4 parts by mass (Super Becamine G-821-60, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Titanium oxide 40 parts by mass ・ Methyl ethyl ketone 50 parts by mass

<Coating liquid for charge generation layer>
-Bisazo pigment represented by the following structural formula (1) 2.5 parts by mass- Polyvinyl butyral (XYHL, manufactured by UCC) 0.5 parts by mass- Cyclohexanone 200 parts by mass- Methyl ethyl ketone 80 parts by mass

[Coating liquid for charge transport layer]
-10 parts by weight of bisphenol Z polycarbonate (Panlite TS-2050, manufactured by Teijin Chemicals Ltd.)
-7 parts by mass of a low molecular charge transport material represented by the following structural formula (2)-100 parts by mass of tetrahydrofuran-1 part by mass of tetrahydrofuran solution of 1% silicone oil (KF50-100CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

Next, a surface layer coating solution having the following composition was applied onto the laminate comprising the conductive support / intermediate layer / charge generation layer / charge transport layer using a spray coating method, and then a metal halide lamp was used to produce illuminance. : 900 mW / cm ² , Irradiation time: The surface layer was crosslinked by light irradiation under the conditions of 20 seconds to obtain a cured surface film of 5.0 μm. Thereafter, drying was performed at 130 ° C. for 30 minutes to obtain an electrophotographic photosensitive member comprising a conductive support / intermediate layer / charge generation layer / charge transport layer / surface layer.

<Coating liquid for surface layer>
-Radical polymerizable monomer having a charge transporting structure represented by the following structural formula (3) [trimethylolpropane triacrylate (TMPTA, manufactured by Tokyo Chemical Industry Co., Ltd.)]
85.5 parts by mass A radical polymerizable compound having a charge transporting structure represented by the following structural formula (4)
85.5 parts by mass / photopolymerization initiator 9 parts by mass [1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure I-184, manufactured by Ciba Specialty Chemicals)]
・ Organic inorganic composite fine particle 1 20 parts by mass ・ Fluorosurfactant (Modiper F210 (solid content 3 mass%), manufactured by NOF Corporation)
2 parts by mass, tetrahydrofuran 1200 parts by mass

[Example 2]
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the surface layer coating solution in Example 1 was changed to the following.
<Coating liquid for surface layer>
-Radical polymerizable monomer having no charge transporting structure represented by the structural formula (3) [Trimethylolpropane triacrylate (TMPTA, manufactured by Tokyo Chemical Industry Co., Ltd.)]
66.5 parts by mass-radical polymerizable compound having a charge transporting structure represented by the structural formula (4)
66.5 parts by mass / photopolymerization initiator 7 parts by mass [1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure I-184, manufactured by Ciba Specialty Chemicals)]
・ Organic inorganic composite fine particle 1 60 parts by mass ・ Fluorosurfactant (Modiper F210 (solid content 3% by mass), manufactured by NOF Corporation)
6 parts by mass / tetrahydrofuran 1200 parts by mass

Example 3
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the surface layer coating solution in Example 1 was changed to the following.
<Coating liquid for surface layer>
-Radical polymerizable monomer having no charge transporting structure represented by the structural formula (3) [Trimethylolpropane triacrylate (TMPTA, manufactured by Tokyo Chemical Industry Co., Ltd.)]
47.5 parts by mass A radically polymerizable compound having a charge transporting structure represented by the structural formula (4)
47.5 parts by mass / photopolymerization initiator 5 parts by mass [1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure I-184, manufactured by Ciba Specialty Chemicals)
・ Organic inorganic composite fine particle 1 100 parts by mass ・ Fluorosurfactant (Modiper F210 (solid content 3% by mass), manufactured by NOF Corporation)
10 parts by mass · 1800 parts by mass of tetrahydrofuran

[Examples 4 to 6]
An electrophotographic photosensitive member was produced in the same manner as in Examples 1 to 3 except that the organic-inorganic composite fine particles used in the surface layer of Examples 1 to 3 were changed to the organic-inorganic composite fine particles 2.

Example 7
An electrophotographic photoreceptor in the same manner as in Example 2 except that 66.5 parts by mass of the radical polymerizable monomer having no charge transporting structure used in the surface layer coating solution of Example 2 was changed to the following. Was made.
-Radical polymerizable monomer having no charge transporting structure (two mixed monomers using the following (1) and (2) in a weight ratio of 1: 1) 66.5 parts by mass (1) Trimethylolpropane triacrylate (structure) Formula (3) TMPTA, manufactured by Tokyo Chemical Industry Co., Ltd.
(2) Caprolactone-modified dipentaerythritol hexaacrylate (Structural Formula (5) KAYARAD DPCA-120, Nippon Kayaku Co., Ltd.)

Example 8
Electrophotography in the same manner as in Example 7 except that the radical polymerizable monomer having the charge transporting structure used in the surface layer coating solution of Example 7 was changed to the one represented by the following structural formula (6). A photoconductor was prepared.

Example 9
Electrophotography in the same manner as in Example 7 except that the radical polymerizable monomer having the charge transporting structure used in the coating solution for the surface layer of Example 7 was changed to that represented by the following structural formula (7). A photoconductor was prepared.

Example 10
An electrophotographic photosensitive member was produced in the same manner as in Example 7, except that the following coating solution for the surface layer used in Example 7 did not use a fluorosurfactant.
<Coating liquid for surface layer>
-Radical polymerizable monomer having no charge transport structure (two mixed monomers using the following (1) and (2) at a mass ratio of 1: 1) 66.5 parts by mass (1) trimethylolpropane triacrylate (structure Formula (3) TMPTA, manufactured by Tokyo Chemical Industry Co., Ltd.
(2) Caprolactone-modified dipentaerythritol hexaacrylate (Structural Formula (5) KAYARAD DPCA-120, Nippon Kayaku Co., Ltd.)
A radical polymerizable compound having a charge transporting structure represented by the structural formula (4)
66.5 parts by mass / photopolymerization initiator 7 parts by mass [1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure I-184, manufactured by Ciba Specialty Chemicals)]
・ Organic inorganic composite fine particles 1 60 parts by mass Tetrahydrofuran 1200 parts by mass

[Comparative Example 1]
An electrophotographic photosensitive member was produced in the same manner as in Example 7, except that the surface layer coating solution used in Example 7 was changed to the following one containing no organic-inorganic composite fine particles.
<Coating for surface layer>
-Radical polymerizable monomer having no charge transporting structure (two mixed monomers using the following (1) and (2) at a mass ratio of 1: 1) 95 parts by mass (1) Trimethylolpropane triacrylate (structural formula ( 3) TMPTA, manufactured by Tokyo Chemical Industry Co., Ltd.
(2) Caprolactone-modified dipentaerythritol hexaacrylate (Structural Formula (5) KAYARAD DPCA-120, Nippon Kayaku Co., Ltd.)
A radical polymerizable compound having a charge transporting structure represented by the structural formula (4)
95 parts by mass / photopolymerization initiator 10 parts by mass [1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure I-184, manufactured by Ciba Specialty Chemicals)]
・ 1200 parts by mass of tetrahydrofuran

[Comparative Example 2]
An electrophotographic photosensitive member was produced in the same manner as in Example 2 except that the surface layer coating solution used in Example 2 was changed to the following.
<Coating liquid for surface layer>
-Radical polymerizable monomer having no charge transporting structure (two kinds of mixed monomers using the following (1) and (2) at a mass ratio of 1: 1) 66.5 parts by mass (1) Trimethylolpropane triacrylate (structure) Formula (3) TMPTA, manufactured by Tokyo Chemical Industry Co., Ltd.
(2) Caprolactone-modified dipentaerythritol hexaacrylate (Structural Formula (5) KAYARAD DPCA-120, Nippon Kayaku Co., Ltd.)
A radical polymerizable compound having a charge transporting structure represented by the structural formula (4)
66.5 parts by mass / photopolymerization initiator 7 parts by mass [1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure I-184, manufactured by Ciba Specialty Chemicals)]
・ Fluorine resin fine particles (Fluon L170J, manufactured by Asahi Glass Co., Ltd.) 60 parts by mass • Fluorosurfactant 6 parts by mass [Modiper F210 (solid content: 3% by mass), manufactured by NOF Corporation]
・ 1200 parts by mass of tetrahydrofuran

[Comparative Example 3]
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 2, except that the fluororesin fine particles used in the surface layer coating solution of Comparative Example 2 were changed to the organic-inorganic composite fine particles 3 produced by the above-described method.

[Comparative Example 4]
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 2, except that the fluororesin fine particles used in the surface layer coating liquid of Comparative Example 2 were changed to the organic-inorganic composite fine particles 4 produced by the above-described method.

[Comparative Example 5]
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 2, except that the fluororesin fine particles used in the surface layer coating solution of Comparative Example 2 were changed to the organic-inorganic composite fine particles 5 produced by the above-described method.

[Comparative Example 6]
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 2 except that the surface layer coating solution in Comparative Example 2 was changed to the following.
<Coating liquid for surface layer>
-Radical polymerizable monomer having no charge transporting structure (two kinds of mixed monomers using the following (1) and (2) at a mass ratio of 1: 1) 188.1 parts by weight (1) Trimethylolpropane triacrylate (structure) Formula (3) TMPTA, manufactured by Tokyo Chemical Industry Co., Ltd.
(2) Caprolactone-modified dipentaerythritol hexaacrylate (Structural Formula (5) KAYARAD DPCA-120, Nippon Kayaku Co., Ltd.)
A radical polymerizable compound having a charge transporting structure represented by the structural formula (4)
188.1 parts by mass / photopolymerization initiator 19.8 parts by mass [1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure I-184, manufactured by Ciba Specialty Chemicals)]
・ Organic inorganic composite fine particle 1 4 parts by mass ・ Fluorosurfactant 0.4 part by mass (Modiper F210 (solid content 3% by mass), manufactured by NOF Corporation)
・ 2400 parts by mass of tetrahydrofuran

[Comparative Example 7]
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 2 except that the surface layer coating solution in Comparative Example 2 was changed to the following.
<Coating liquid for surface layer>
-Radical polymerizable monomer having no charge transporting structure (two mixed monomers using the following (1) and (2) in a mass ratio of 1: 1) 93.1 parts by mass (1) Trimethylolpropane triacrylate (structure) Formula (3) TMPTA, manufactured by Tokyo Chemical Industry Co., Ltd.
(2) Caprolactone-modified dipentaerythritol hexaacrylate (Structural Formula (5) KAYARAD DPCA-120, Nippon Kayaku Co., Ltd.)
A radical polymerizable compound having a charge transporting structure represented by the structural formula (4)
93.1 parts by mass / photopolymerization initiator 9.8 parts by mass [1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure I-184, manufactured by Ciba Specialty Chemicals)]
・ Organic inorganic composite fine particle 1 4 parts by mass-Fluorosurfactant 0.4 part by mass [Modiper F210 (solid content 3% by mass), manufactured by NOF Corporation]
・ 1200 parts by mass of tetrahydrofuran

[Comparative Example 8]
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 2 except that the surface layer coating solution in Comparative Example 2 was changed to the following.
<Coating liquid for surface layer>
-Radical polymerizable monomer having no charge transporting structure (two mixed monomers using the following (1) and (2) at a mass ratio of 1: 1) 85.5 parts by mass (1) Trimethylolpropane triacrylate (structure) Formula (3) TMPTA, manufactured by Tokyo Chemical Industry Co., Ltd.
(2) Caprolactone-modified dipentaerythritol hexaacrylate (Structural Formula (5) KAYARAD DPCA-120, Nippon Kayaku Co., Ltd.)
A radical polymerizable compound having a charge transporting structure represented by the structural formula (4)
85.5 parts by mass / photopolymerization initiator 9 parts by mass [1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure I-184, manufactured by Ciba Specialty Chemicals)]
-Organic inorganic composite fine particle 2 220 parts by mass-Fluorosurfactant 22 parts by mass [Modiper F210 (solid content 3% by mass), manufactured by NOF Corporation]
・ 4000 parts by mass of tetrahydrofuran

[Comparative Example 9]
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 2 except that the surface layer coating solution in Comparative Example 2 was changed to the following.
<Coating liquid for surface layer>
-Radical polymerizable monomer having no charge transporting structure (two mixed monomers using the following (1) and (2) in a mass ratio of 1: 1) 38 parts by mass (1) Trimethylolpropane triacrylate (structural formula ( 3) TMPTA, manufactured by Tokyo Chemical Industry Co., Ltd.
(2) Caprolactone-modified dipentaerythritol hexaacrylate (Structural Formula (5) KAYARAD DPCA-120, Nippon Kayaku Co., Ltd.)
A radical polymerizable compound having a charge transporting structure represented by the structural formula (4)
38 parts by mass / photopolymerization initiator 4 parts by mass [1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure I-184, manufactured by Ciba Specialty Chemicals)]
・ Organic inorganic composite fine particle 1 120 parts by mass-Fluorosurfactant 12 parts by mass [Modiper F210 (solid content 3% by mass), manufactured by NOF Corporation]
・ 2000 parts by mass of tetrahydrofuran

[Example 11]
The radical polymerizable compound having no charge transporting structure used in the surface layer coating liquid of Example 7 was converted into a radical polymerizable monomer having no charge transporting structure (1,6-hexanediol diacrylate, An electrophotographic photosensitive member was produced in the same manner as in Example 7 except that the product was changed to Kogaku Pharmaceutical Co., Ltd.

  Next, the following tests were carried out on the produced electrophotographic photosensitive members of Examples 1 to 11 and Comparative Examples 1 to 9.

<< Evaluation of the proportion of organic / inorganic composite fine particles in the surface layer >>
The ratio of the organic / inorganic composite fine particles to the surface layer was evaluated using a field emission scanning electron microscope S-4200 (manufactured by Hitachi, Ltd.) capable of EDS measurement. Specifically, a cross section in the radial direction is formed on the electrophotographic photosensitive member using a microtome, and fluorine and silicon are mapped at a magnification of 5000 using the electron microscope at any 10 observation points on the cross section. . Using the image processing software (IMAGE Pro Plus) for the obtained mapping image, the sum of the fluorine atom detection ratio and the Si element detection ratio in the observation area is calculated, and the 10-point average value is calculated as the surface layer of the organic / inorganic composite fine particles. As a percentage.

<< Evaluation of the proportion of inorganic material in organic / inorganic composite fine particles >>
Evaluation of the proportion of the inorganic material in the organic-inorganic composite fine particles was also performed in the same manner as the evaluation of the proportion in the surface layer of the organic-inorganic composite fine particles. Specifically, the observation magnification of the cross section of the electrophotographic photosensitive member was set to 10,000 times, and fluorine and silicon were mapped at arbitrary observation points. Next, using the image processing software (IMAGE Pro Plus), calculate the area ratio of silicon in the domain formed by fluorine and silicon, and convert the obtained mapping image to volume ratio by 3/2. Sought by.

<< Evaluation of the area ratio of the fluororesin contained in the organic / inorganic composite fine particles on the photoreceptor surface >>
Evaluation of the area ratio of the fluororesin contained in the organic / inorganic composite fine particles on the surface of the photoreceptor was also performed in the same manner. Specifically, fluorine mapping is performed at a magnification of 5000 times with respect to 10 arbitrary observation points on the surface of the electrophotographic photoreceptor using the electrophotographic microscope. Using the image processing software (IMAGE Pro Plus) for the obtained mapping image, the fluorine atom detection ratio occupying the observation area is calculated, and the 10-point average value is defined as the area ratio of the fluororesin photoreceptor surface. The coefficient of variation was also calculated.

<Evaluation of elastic power of electrophotographic photosensitive member>
The electrophotographic photosensitive member was evaluated using a surface film physical property tester Fischerscope H-100 (manufactured by Fischer Instruments). For the measurement, a Vickers indenter was used as an indenter, and a load unloading test was performed once by a load unloading repeated test method. As the measurement conditions, the maximum load was 9.8 mN, the load (unloading) time was 30 seconds, the creep time was 5 seconds, the elastic power was measured at any five locations, and the average value of the average values of the electrophotographic photosensitive member was measured. The elastic power was used.

<Evaluation of friction coefficient of electrophotographic photoreceptor surface>
The coefficient of friction of the photoreceptor surface was measured by the Euler belt method using the apparatus shown in FIG. PPC paper (type 6200, manufactured by Ricoh Co., Ltd.) cut into a strip of 3 cm width is brought into contact with the outer peripheral quarter portion of the photoreceptor surface so that the paper cutting direction is the longitudinal direction, and 100 g of one side (lower end) is contacted. A load was applied, a force gauge was connected to the other, the force gauge was moved at a constant speed, and the force (peak value) when the paper started to move was read with the force gauge and calculated from the following formula.
μs = 2 / π × ln (F / W)
μs: Coefficient of static friction F: Force gauge reading W: Load (100 g)

《Running test with actual machine》
As an actual machine running, a modified Ricoh IPSiO Color CX9000 was used. In the test, a device modified beforehand so that the lubricant bar was removed from the professional back cartridge and the lubricant was not supplied from the outside of the photoreceptor was used. Ipsio toner type 9800 was used as the toner, and MyPaper (A4 size) manufactured by NBS Ricoh was used as the paper passing paper. As the running condition, the charging condition is adjusted so that the photosensitive member surface potential is −650 V at the start, and the change in the charging potential and the exposed portion potential due to the running is evaluated, the change in the friction coefficient of the photosensitive member surface is evaluated, and the cleaning is performed. The evaluation of the property and the wear amount of the photoreceptor were also carried out. The image used for paper passing was a 5% test chart and 100,000 sheets were run.

[Various characteristics of electrophotographic photoreceptor surface]
“Evaluation of ratio of inorganic material in organic / inorganic composite fine particles”, “Organization ratio of organic / inorganic composite fine particles”, “Organic / organic composite fine particles” of electrophotographic photoreceptors obtained in Examples 1-11, Comparative Examples 1-9 Table 1 shows the evaluation results of the “area ratio of the fluororesin contained in the inorganic composite fine particles on the surface of the photoreceptor” and the “elastic modulus of the electrophotographic photoreceptor surface layer”, and Tables 2 and 3 show the results of running tests using actual machines. .

  As is clear from these results, with respect to Examples 1 to 11, by using the organic-inorganic composite fine particles described in the present invention, the occurrence of poor cleaning due to continued running is suppressed, while the post-charge potential and the post-exposure potential. It can be seen that this is an excellent electrophotographic photosensitive member in which such fluctuations do not occur. The reason why the cleaning property does not vary with running can be explained from the viewpoint of the friction coefficient shown in Table 2. That is, when a normal electrophotographic photosensitive member is used (Comparative Example 1), the surface friction coefficient of the electrophotographic photosensitive member increases rapidly according to use, and the frictional resistance between the cleaning blade and the surface of the electrophotographic photosensitive member increases. The cleaning blade vibrates (so-called squeal phenomenon) due to the toner, and the phenomenon that the toner cannot be partially cleaned occurs. However, the electrophotographic photosensitive member according to the present invention (Examples 1 to 11) is formed on the surface of the electrophotographic photosensitive member. The friction coefficient is stable at a low level, stable cleaning can be realized even during running, and the effect of the invention is considered to be sufficiently exhibited.

  On the other hand, in the electrophotographic photoreceptor (Comparative Example 2) to which fluororesin fine particles having simply lubricity are added, the cleaning performance during running is maintained as in Examples 1-11, but The amount of wear is very large, suggesting that it is difficult to apply to an electrophotographic photoreceptor having wear durability. In addition, it is not necessary that the organic fine particles contain inorganic fine particles. When the addition amount is small as in Comparative Example 4, it is shown that the effect of reducing the abrasion amount of the electrophotographic photosensitive member is great. However, it is not sufficient as compared with the results of the examples, and in applying the present invention, it was shown that the composition ratio of the organic / inorganic fine particles greatly affects the life extension of the electrophotographic photosensitive member. ing.

  Furthermore, significant knowledge can be obtained from the electrophotographic photoreceptors of Comparative Examples 6 to 9 regarding the amount of organic / inorganic fine particles added to the surface layer. That is, when the amount added is small and the surface coverage with the fluororesin is less than 5%, the friction coefficient takes a relatively large value from the beginning as shown in Table 2, and further the organic inorganic in the surface layer It is shown that when the addition amount of the fine particles is less than 3 vol%, the effect does not continuously appear (Comparative Example 6). In addition, even when the surface coverage is higher than 5%, if the volume ratio is lower than 3 vol%, it can be seen that the sustainability of the effect is low as in Comparative Example 6. On the other hand, even when the addition amount is sufficiently large, when the proportion of the organic / inorganic fine particles in the surface layer exceeds 40 vol% (Comparative Examples 8 to 9), the charge transport that the electrophotographic photosensitive member should originally have. Therefore, when the surface coverage is higher than 50 vol% (Comparative Example 9), the wear durability tends to be impaired. I understand that. From the above, the addition amount of the organic inorganic fine particles and the surface coverage of the fluororesin described in the present invention are important factors for obtaining an electrophotographic photoreceptor having wear durability and excellent cleaning properties. It is clear that Further, when the dispersibility is insufficient, the fluororesin composition is biased in the surface layer, so that it cannot be an electrophotographic photoreceptor exhibiting excellent wear durability and cleaning properties as shown in the examples. .

  The results of Example 11 show that selection of the binder material is also effective for obtaining an electrophotographic photoreceptor excellent in wear durability.

  From the results of the above Examples and Comparative Examples, the electrophotographic photosensitive member described in the present invention has excellent wear durability and electrical characteristics, and exhibits excellent toner cleaning properties over a long period of time. It was shown to be a body.

1 Electrophotographic photoreceptor 2 Static elimination lamp (static elimination means)
3 Charger (charging means)
5 Image exposure unit (exposure means)
6 Development unit (development means)
7 Pre-transfer charger 8 Registration roller 9 Transfer body 10 Transfer charger (transfer means)
DESCRIPTION OF SYMBOLS 11 Separation charger 12 Separation claw 13 Charger before cleaning 14 Fur brush 15 Cleaning blade 31 Conductive support body 32 Intermediate layer 33 Charge generation layer 34 Charge transport layer 35 Surface layer 102 Charging means 103 Exposure means 104 Developing means 105 Transfer body 106 Transfer means 107 Cleaning means

JP-A-5-181299 JP 2002-6526 A JP 2002-82465 A JP 2000-284514 A JP 2001-194413 A JP 2005-17469 A JP 2005-227676 A JP 2005-321628 A JP 2003-66641 A JP 2005-10363 A Japanese Patent No. 3972589 JP 2003-307867 A Japanese Patent No. 41188839 JP 2002-82466 A JP 2006-99028 A Japanese Patent Laid-Open No. 9-26685 JP 2002-229241 A Japanese Patent Laid-Open No. 3-45762 Japanese Patent Laid-Open No. 7-281463 JP 2006-259141 A

Claims (16)

  It has at least an intermediate layer, a photosensitive layer, and a surface layer in this order on a conductive support, and the surface layer is composed of at least a radical polymerizable compound and a photo radical polymerization initiator, and is formed by polymerization using light energy irradiation means. In the electrophotographic photoreceptor, the surface layer contains organic-inorganic composite fine particles composed of at least a fluororesin and an inorganic material, and the volume average particle diameter Dv of the organic-inorganic composite fine particles is 0.05 μm or more and 3.0 μm or less, The ratio of the inorganic material in the organic / inorganic composite fine particles is 3 vol% or more and 40 vol% or less, and the ratio of the organic / inorganic composite fine particles in the surface layer is 5 vol% or more and 40 vol% or less. Photoconductor.   The average value of the area ratio of the fluororesin contained in the organic-inorganic composite fine particles on the surface of the photoreceptor is 5% or more and 50% or less, and the variation coefficient of the area ratio is 0.10 or less. The electrophotographic photosensitive member according to claim 1.   The fluororesin contained in the organic / inorganic composite fine particles is any one of polytetrafluoroethylene, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, and polyvinylidene fluoride. The electrophotographic photosensitive member according to claim 1, comprising at least.   4. The electrophotographic photosensitive member according to claim 1, wherein the inorganic material contained in the organic-inorganic composite fine particles contains at least one of aluminum oxide, titanium oxide, silicon oxide, and molybdenum sulfide. body.   The electrophotographic photoreceptor according to claim 1, wherein the functional group of the radical polymerizable compound is an acryloyloxy group and / or a methacryloyloxy group.   6. The electrophotographic photoreceptor according to claim 1, wherein the radical polymerizable compound is a radical polymerizable compound having no charge transport structure.   The electrophotographic photoreceptor according to claim 6, wherein the radical polymerizable compound having no charge transporting structure has three or more functional groups.   6. The electrophotographic photosensitive member according to claim 1, wherein the radical polymerizable compound is a radical polymerizable compound having a charge transport structure.   9. The electrophotographic photoreceptor according to claim 8, wherein the charge transporting portion of the radical polymerizable compound having the charge transporting structure has a triarylamine structure.   The electrophotographic photosensitive member according to claim 8 or 9, wherein the radical polymerizable compound having the charge transporting structure has one functional group.   11. The electron according to claim 1, wherein the radical polymerizable compound is a mixture of a radical polymerizable compound having no charge transport structure and a radical polymerizable compound having a charge transport structure. Photoconductor.   The electrophotographic photosensitive member according to claim 1, wherein the surface layer has an elastic power of 40% or more.   The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer comprises a laminate of a charge generation layer and a charge transport layer.   A charging process for charging at least the electrophotographic photosensitive member using the electrophotographic photosensitive member according to claim 1, and an electrostatic latent image on the surface of the electrophotographic photosensitive member charged by the charging process. A latent image forming process to be formed, a developing process for attaching toner to an image portion of an electrostatic latent image formed by the latent image forming process, and a transfer process for transferring a visible image formed by the developing process to a transfer target An image forming method characterized by repeating the above.   14. An electrophotographic photosensitive member according to claim 1, comprising at least a charging means for charging the electrophotographic photosensitive member, and an electrostatic latent image on the surface of the electrophotographic photosensitive member charged by the charging means. A process cartridge for an image forming apparatus, which is integrally provided with one means selected from a latent image forming means for forming a toner and a developing means for attaching toner to an image portion of an electrostatic latent image formed by the latent image forming means. An image forming apparatus, wherein the image forming apparatus is mounted and the process cartridge for the image forming apparatus is detachable.   14. An electrophotographic photosensitive member according to claim 1, comprising at least a charging means for charging the electrophotographic photosensitive member, and forming a latent image on the surface of the electrophotographic photosensitive member charged by the charging means. A process cartridge for an image forming apparatus, comprising: a latent image forming unit configured to cause the toner to adhere to an image portion of an electrostatic latent image formed by a latent image forming unit.