JP2006195154A - Image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method which uses a photo conductor less wearing with high durability and prevents uneven images due to contamination on the charging component in highly humid environments and can obtain stabilized images. <P>SOLUTION: The photo conductor has a universal hardness HU of 150 or larger but 240 or less (N/mm<SP>2</SP>) on its surface and an elastic deformation of 44% or larger but 65% or less. The toner contains inorganic fine powder of perovskite crystals 80-220 nm in the mean size of the primary particles, and a cleaner is provided to clean the charging component. The cleaner is in contact with the charging component at least when forming images, and its part in contact with the charging component makes a brush moving back and forth in the length direction of the charging component. The fiber density F of this brush (fibers/10 mm) and the fiber diameter D (μm) satisfies the following formulas: -2,300×d+680≤F≤-4,500×d+1,350 and is within the range 200×d≤D≤600×d, when denoting the mean size of the initial particles of the inorganic fine particles of this perovskite crystals by d (μm). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a photoreceptor used in a recording method using an electrophotographic method, an electrostatic recording method, or the like, and an image forming method. Specifically, the electrostatic latent image formed on the electrostatic latent image carrier is developed with toner, and then transferred onto a transfer material to form an image. It is about the method.

  In recent years, with the aim of reducing running costs and reducing image degradation (dot reproducibility, etc.), electrophotography that can improve wear resistance and scratch resistance by increasing the film strength of the photoconductor, extending the life span. There is a need for a photoreceptor.

  As such an electrophotographic photoreceptor, a protective layer is provided on the photosensitive layer, and the protective layer is achieved by using a surface layer containing a compound obtained by polymerizing an unsaturated polymerizable functional group in the molecule. (See Patent Documents 1 and 2).

  As a method for charging the photosensitive member, a contact charging method in which a charging member is brought into contact with the photosensitive member for charging is known. For example, while applying a voltage to the conductive roller, the roller is brought into contact with a member to be charged such as a photosensitive member, and the surface of the member to be charged is charged to a predetermined potential. If such a contact charging means is used, the voltage can be lowered as compared with the corona discharger, and the amount of ozone generated can be reduced.

  However, these contact charging devices perform charging in a minute space between the photosensitive member and the charging member, that is, charging at a position closer to the photosensitive member, compared to a charging device (corona) that is not in contact with the photosensitive member. As compared with conventional non-contact type charging devices, the surface of the photoconductor changes and oxidative degradation occurs more violently, and the discharge products generated during charging tend to adhere to the surface of the photoconductor.

  The surface of such a photoconductor easily adsorbs moisture, and by adsorbing moisture, surface resistance is lowered, and an image defect called a flow image is likely to occur.

  In particular, in the case of the electrophotographic photosensitive member having improved wear resistance as described above, since the amount of abrasion of the photosensitive member itself is small, the discharge product generated in the primary charging process and adhered to the surface of the photosensitive member is, for example, cleaned. It is difficult to remove with a scraping force with a blade or the like, and problems such as image flow in a high-humidity environment, damage to the cleaning blade, and drooling occur.

  As a method for solving these problems, it is known that these problems can be improved by adding particles having an abrasive action to the toner and stripping off the charged products adhering to the surface of the photoreceptor as described above. It has been. However, conventionally used abrasive particles have a large particle size and a broad particle size distribution, so that it is necessary to add a large amount to the toner in order to uniformly polish the surface of the photoreceptor. In particular, problems such as scattering, reversal fogging, and accumulation of abrasive particles were likely to occur. As an improvement of this point, strontium titanate with a small particle size and reduced looseness is proposed, and there is also an inorganic fine powder that has an excellent polishing effect when added in a small amount (for example, see Patent Document 3). ). However, in particular, in the case of use in a high humidity environment, when a photoconductor having high wear resistance is used, it is insufficient for removing the charged product.

  Also, as the durability of the photoconductor progresses, the dust on the surface layer of the photoconductor accumulates in the vicinity of the blade, thereby preventing the toner from slipping through the blade. While the effect of reducing friction and preventing damage to the blade is increased, when using a highly wear-resistant photoconductor, the photoconductor itself is less likely to be scraped. The blocking layer and the friction reducing effect due to the powder are reduced, and fine particles are more likely to slip through, and charging failure due to contamination of the charging member is likely to occur.

  Further, when such fine particles are added, the fine particles slip through the cleaning blade as the durability progresses. However, by slipping, the friction with the blade is reduced, and the effect of reducing damage to the blade is also increased, however, the dirt on the charging member is noticeably caused by the fine inorganic fine powder that has slipped through, particularly with high adhesion. appear.

  In particular, when using a photoconductor that is highly durable and used in a high-humidity environment where many external additives pass through, the particles attached to the charging member adsorb moisture when used in a high-humidity environment. Therefore, uniform charging and charging potential can be obtained without greatly affecting the charging. However, if the image forming apparatus used in the high humidity environment is moved to the low humidity environment and the image is printed, Water is removed from the fine particles adhering to the charging member and the resistance is further increased, and the charging uniformity and the charging potential are remarkably lowered, and the phenomenon that the image defect is caused accordingly appears remarkably.

JP 2000-66425 A JP 2000-206715 A Japanese Patent Laid-Open No. 10-10770

  An object of the present invention is to provide an image forming method that solves the above-described problems. Specifically, when using a high-abrasion-resistant photoconductor that can be expected to improve image quality and extend the life, and using toner with abrasive particles that can prevent image flow, external addition from the cleaning blade It is an object of the present invention to provide an image forming method in which the charging member is prevented from being soiled by slipping of the agent, and primary charging failure and image failure due to charging unevenness are suppressed.

In order to solve the above-described problems, the present invention provides a step of bringing a rotatable charging member into contact with a photosensitive member having a photosensitive layer and a protective layer on a support and charging the electrostatic latent image on the charged photosensitive member. An electrostatic latent image forming step to be formed; a developing step of transferring the toner carried on the toner carrying member to the electrostatic latent image for visualization; and the toner image formed on the photoconductor through an intermediate transfer member Or without intervention, a transfer process for transferring to a transfer material, a transfer process for electrostatic transfer to a transfer material, and a cleaning process for removing transfer residual toner remaining on the photoreceptor after the transfer process from the photoreceptor. In the method
The universal hardness value HU of the photoreceptor surface is 150 or more and 240 or less (N / mm ² ), and the elastic deformation rate is 44% or more and 65% or less,
The toner includes toner particles having at least a binder resin and a colorant, and a perovskite crystal inorganic fine powder having a cubic and / or rectangular parallelepiped shape and an average primary particle diameter of 80 nm to 220 nm. A toner having at least
A cleaning member is provided for cleaning the charging member. The cleaning member contacts the charging member at least during image formation, and a portion in contact with the charging member reciprocates in the longitudinal direction of the charging member. When the average particle size of primary particles of the inorganic fine powder of the perovskite crystal is d (μm), the fiber density F of the brush (fibers / 10 mm) and the fiber diameter D (μm) are expressed by the following formula: This is achieved by an image forming method characterized by
−2300 × d + 680 ≦ F ≦ −4500 × d + 1350 and 200 × d ≦ D ≦ 600 × d

  According to the present invention, even when a highly durable drum with less wear due to durability is used, the discharge product adhering to the drum surface can be scraped well by the cleaning blade portion, image flow, damage to the blade In addition, it is possible to prevent charging failure due to contamination of the charging member and image failure due to uneven charging, and to provide a highly durable image forming method.

  Next, the image forming method of the present invention will be described below with reference to the accompanying drawings. 1 and 2 show an example of a specific apparatus that can be used for carrying out the image forming method of the present invention.

  1 and 2, reference numeral 1 denotes a photosensitive drum, and a primary charging roller 6, a developing device 7, and a transfer charging roller 2 are provided around the photosensitive drum. The photosensitive member 1 is charged by a primary charging roller 6 that contacts the photosensitive member. And it exposes by irradiating the photoreceptor 1 with the laser beam L with a laser generator. The electrostatic latent image on the photoreceptor 1 is developed with toner by the developing unit 7 and transferred onto the transfer material 1 by the transfer roller 2 in contact with the photoreceptor via the transfer material. The transfer material on which the toner image is placed is conveyed to the fixing device 3 through the conveyance guide and is fixed on the transfer material. In addition, toner partially remaining on the photoconductor is removed from the surface of the photoconductor by the cleaning elastic blade 4 in contact with the photoconductor, and contaminants such as inorganic powder adhering to the charging roller are charged by the cleaning member 9. This is an image forming method that is removed from the surface of a member.

A feature of the present invention is a toner containing inorganic fine powders of perovskite crystals in which the average particle diameter of primary particles having a cubic shape and / or a rectangular parallelepiped shape is 80 nm to 220 nm. The brush, which is a cleaning member capable of reciprocating in the longitudinal direction of the charging roller 6, has a fiber density F (10 mm) and a fiber diameter D (μm) of the average primary particles of the inorganic fine powder of the perovskite crystal. When the particle diameter is d (μm),
−2300 × d + 680 ≦ F ≦ −4500 × d + 1350 and 200 × d ≦ D ≦ 600 × d
It is that the brush of the range of contact | abuts.

  The finer the particle size of the inorganic fine powder, the higher the adhesion to the charging roller. Therefore, when the fiber density of the brush is sparse or the fiber diameter is large, the removal from the charging member is sufficiently performed. Instead, uneven charging occurs. As a result of investigations, in order to sufficiently clean and remove the charging member, the fiber density F of the brush (10 mm), the fiber diameter D (μm), and the average particle diameter of the primary particles of the inorganic fine powder were determined. When d (μm), it was found that −2300 × d + 680 ≦ F ≦ −4500 × d + 1350 and 200 × d ≦ D ≦ 600 × d (the inside of the hatched area in FIG. 13 showed good characteristics) ).

  When the brush is contacted as it is without reciprocating, the contacted part and the non-contacted part become clear, and the surface of the charging roller is streaked in the same direction as the rotation direction of the photosensitive member. Occurs, and uneven charging occurs. By reciprocating, the portion of the charging roller that is not in contact in the longitudinal direction is reduced as much as possible, and moving the brush in this way also has the effect of increasing the removal of particles adhering to the surface.

  When the fiber density is less than −2300 × d + 680, sufficient cleaning ability cannot be exhibited. In particular, when the durability progresses, uneven charging occurs, and even if the fiber diameter exceeds 600 × d, the rubbing force increases, but it is fine. The ability to scrape particles is reduced, the cleaning ability is insufficient, the surface layer of the charging member is worn, the surface layer is scratched, and current leaks from that part Occurs. Further, if the fiber diameter is less than 200 × d, there will be a problem in durability of the brush itself, and the brush will be broken or the brush will be detached (the larger the particle size of the inorganic fine powder, the more the brush and the inorganic particles get caught). (The frictional force increases and the fiber diameter needs to be thickened because it tends to tear off), and the brush fibers are sandwiched between the cleaning blades, resulting in poor cleaning, damage to the blades, and the photoreceptor. The problem of the occurrence of scratches on the surface arises. When the fiber density exceeds −4500 × d + 1350, the reciprocating movement of the brush portion that is in contact with the charging member is likely to be hindered, and the cleaning ability of the brush is reduced.

  The fiber diameter of the brush can be measured by observing the cross section of the brush with an optical microscope, and the fiber density is the number of brushes per unit length in the longitudinal direction of the brush, for example, in the case of a sheet state. In the case of a roller and a pad brush, it means the number per unit length of a straight line connecting the brush flocked portion in the longitudinal direction of the cleaning member.

  The reciprocating movement of the brush cleaning member needs to be moved in the longitudinal direction of the charging roller (shown in FIG. 6). If the reciprocating movement is not performed, the cleaning roller abuts on the surface of the charging roller. Smearing occurs, resulting in image defects due to uneven charging. The reciprocating distance of the brush is preferably in the range of 2.5 / d ≧ T ≧ 0.2 / d for T (mm). If it is less than 0.2 / d, the cleaning ability on the surface of the charging member tends to be lowered, and if it exceeds 2.5 / d, the brush will be broken and the damage to the surface of the charging member will increase.

  Further, as shown in FIG. 3, the method of contacting the charging member with the brush as the cleaning member is such that the axis of the cleaning member (thick line in FIG. 3) is different from the rotation axis of the charging member (dashed line in FIG. 3). The contact is preferably made with an intersection angle of 0.01 / d to 0.4 / d.

  When the brush cleaning member comes into contact with the charging member with the predetermined crossing angle as described above, the brush comes into contact with the charging member in an oblique direction with respect to the rotation direction of the charging member. Since a portion that overlaps the contact portion is generated, the portion that does not contact the charging member is reduced, and the charging member can prevent streak-like dirt in the rotation direction of the charging member. This is preferable because the contact area with the member increases and the dirt scraping ability increases accordingly.

  If the crossing angle is less than 0.01 / d, the above-described dirt scraping ability and streak-like dirt prevention ability are low, which is not preferable. If it exceeds 0.4 / d, the load on the brush increases, and This is not preferable because damage to the surface layer of the charging member is increased.

  The material of the brush fiber can be applied to various materials such as rayon, polyester, acrylic, etc. in addition to nylon, and fibers added with additives such as carbon and metal oxides for adjusting resistance and hardness may be used. Absent.

  Moreover, it is preferable that the surface treatment is given to the brush fiber from a durable viewpoint. Cleaning the charging member with a brush is to remove the dirt by scattering the dirt on the surface of the charging member and weakening the adhesive force.If the dirt adheres to the brush, the cleaning ability is reduced, which is not preferable. For example, it is preferable to use a fluorine-based coupling agent having high releasability or a fiber on which a metal compound (such as copper sulfide or tin oxide) is deposited.

  The form of the brush cleaning member is, for example, as shown in FIG. 4, the fur brush roller is brought into contact with the charging member, and the contact portion rotates in the same direction as or opposite to the rotation direction of the charging roller. There are a method of rotating with a difference in peripheral speed, a method of contacting the pad-like brush shown in FIG. 5, and a method of contacting the sheet-like brush shown in FIG. The sheet type which is a structure is preferable.

  Further, when the brush cleaning member is brought into contact with the charging roller, the tip of the brush may be brought into contact (FIG. 7), or in contact with the antinode of the brush with respect to the rotation direction of the charging roller (FIG. 8). However, from the viewpoint of brush durability (brushing or coming off of the brush), it is preferable to contact the tip of the brush.

The photoreceptor has a protective layer, the universal hardness value (hereinafter HU) of the photoreceptor surface is 150 or more and 240 or less (N / mm ² ), and the elastic deformation rate is 44% or more and 65% or less. There must be. By using the photoconductor as described above, mechanical deterioration of the surface of the photoconductor is suppressed, the amount of wear on the surface layer and the scratches on the photoconductor are reduced, and high durability of the photoconductor is achieved.

  In general, the hardness of the film is higher as the amount of deformation with respect to external stress is smaller, and it is considered that the electrophotographic photosensitive member having higher pencil hardness or Vickers hardness naturally improves durability against mechanical deterioration. However, it was found that the high hardness obtained by these measurements did not necessarily improve the durability, and the above range was good.

Although the HU and the elastic deformation rate cannot be separated, for example, when the HU exceeds 240 N / mm ² and the elastic deformation rate is less than 44%, the paper sandwiched between the cleaning blade, the charging, and the transfer roller Since the elastic force of the photoconductor is insufficient for powder, toner, etc., and if the elastic deformation rate is larger than 65%, the elastic deformation amount becomes small even if the elastic deformation rate is high. In particular, a large pressure is applied and scratches are easily generated, and the wear amount of the photosensitive member is also increased. Therefore, it is considered that the one with a high HU is not necessarily optimal as the photosensitive member.

Also, if the HU is less than 150 N / mm ² and the elastic deformation rate exceeds 65%, even if the elastic deformation rate is high, the amount of plastic deformation increases, and the paper dust sandwiched between the cleaning blade, the charging, and the transfer roller If the toner or the toner is rubbed, it will be scraped off or fine scratches will occur, resulting in a shortened durability life.

  HU (Universal Hardness Value) and elastic deformation rate are the microhardness measuring device Fischerscope H100V (Fischer, Inc.) that applies continuous load to the indenter and directly reads the indentation depth under the load to obtain continuous hardness. ). The indenter used was a Vickers square pyramid diamond indenter with a face angle of 136 °.

  An outline of the output chart is shown in FIG. 9, and an example in which the electrophotographic photosensitive member of the present invention is measured is shown in FIG. In FIG. 9, the vertical axis represents the load (mN) and the horizontal axis represents the indentation depth h (μm), and FIG. 10 shows the load increased stepwise (273 points with a holding time of 0.1 s for each point) up to 6 mN. This is the result of reducing the load stepwise in the same manner.

The HU (universal hardness value: hereinafter referred to as HU) of the protective layer of the present invention is defined by the following formula (1) from the indentation depth under the same load when indented at 2 mN.
HU = test load (N) / surface area of Vickers indenter at test load (mm ² )
= 0.002 / 26.43h ² (N / mm ² ) (1)

Similarly to HU, the elastic deformation ratio is obtained from the work amount (energy) performed on the membrane by the indenter pushed at 2 mN, that is, the change in energy due to the increase or decrease of the load on the membrane of the indenter. The value is obtained from 2). The total work Wt (nW) is represented by an area surrounded by A-B-D-A in FIG. 9, and the work W (nW) of elastic deformation is represented by an area surrounded by C-B-D-C. Is done.
Elastic deformation rate We = W / Wt × 100 (%) (2)

  When a highly durable photoconductor as described above is used in an image forming method based on contact charging, image discharge, contamination of the charging member, and damage to the cleaning blade may occur due to the influence of discharge products adhering to the surface of the photoconductor. In order to facilitate, it becomes necessary to remove those discharge products.

  For that purpose, a perovskite crystal in which the average particle size of at least primary particles having a cubic shape and / or a rectangular parallelepiped shape is 80 nm to 220 nm, and the number of particles having an aggregate particle size of 800 nm or more is 1% by number or less. It is necessary to use a toner containing the inorganic fine powder.

  As described above, strontium titanate disclosed in Patent Document 3 is manufactured through a sintering process, and since the shape of the particles is spherical or polyhedral with a nearly spherical shape, the amount of wear is small. When using a photoconductor, the contact area with the photoconductor is small and the shape is close to a sphere, making it easier to slip through the cleaning blade and less likely to stay near the blade. Since it is sufficient and hardly stays in the vicinity of the blade, it is presumed that the frictional force between the blade and the photosensitive member is increased, and the blade is liable to be bent and worn or chipped.

  Therefore, by using inorganic fine powder of a perovskite crystal having a cubic shape and / or a rectangular parallelepiped shape, the shape is angular and slipping from the cleaning blade occurs compared to a nearly spherical polyhedral shape. It is difficult to prevent image defects due to contamination of the charging member, stays in the vicinity of the blade, increases the contact area with the photoconductor, and the ridgeline of the cube or cuboid contacts the photoconductor, thereby Removal and scraping can be performed effectively.

  However, even if the inorganic fine powder of the perovskite type crystal having a cubic shape and / or a rectangular parallelepiped shape is used, a slight slip-through occurs from the cleaning blade, and such fine particles have high adhesion. Therefore, the charging member is contaminated. In particular, when a charging member used in a high humidity environment is used in a low humidity environment, uneven charging appears significantly, and the image pattern (difference between the image portion and non-image portion) causes unevenness in the stain. Will occur.

  Therefore, by using the charging member cleaning member as described above, the dirt on the surface of the charging member is scattered and removed, so that the surface dirt itself and unevenness due to the image pattern are reduced, and a good image is obtained. can get.

  The inorganic fine powder used in the present invention preferably has a perovskite crystal. Among the perovskite inorganic fine powders, more preferable are strontium titanate, barium titanate, and calcium titanate, and among these, strontium titanate is more preferable.

  The inorganic fine powder of perovskite crystal used in the present invention should have an average primary particle size of 80 nm to 220 nm, more preferably 100 nm to 180 nm.

  If the average particle size is less than 80 nm, the polishing effect of the particles in the cleaner part is insufficient, and the slip through the cleaner part is also increased, which is not preferable because it promotes contamination of the charging member. Because the polishing effect at the cleaner section is too strong, the drum may be damaged, the damming effect at the cleaning blade will be higher, and the lubrication action between the blade and the photoreceptor will be reduced, so the load on the blade will be reduced. The problem arises that the blade becomes higher and the blade is bent or the blade itself is chipped and worn.

  In addition, about the particle size of the inorganic fine powder in this invention, it measured by measuring 100 particle size from the photograph image | photographed with the magnification of 50,000 times with the electron microscope.

In addition, the particle size of the inorganic fine powder having a cubic shape and a rectangular parallelepiped shape is as follows when the longest side length (T1) and the shortest short side length (S1) are within the shape of the fine powder. Was used as the particle size of the inorganic fine powder (see FIG. 11).
Particle size of inorganic fine powder = (T1 + S1) / 2

  Further, it is preferable that the content of the inorganic fine powder of the present invention in which the particle shape is cubic and / or rectangular parallelepiped is 60% by number or more because the charged product can be more efficiently removed.

  The cubic and cuboid shape of the inorganic fine powder is a shape as shown in FIG. 12 showing a photograph taken with an electron microscope at a magnification of 50,000 times.

  In the present invention, the amount of the perovskite inorganic fine powder added to the colored particles is preferably 0.05% by mass or more and 5% by mass or less, and more preferably 0.2% by mass or more and 4% by mass or less.

  If the amount is less than 0.05% by mass, the effect of removing the discharge product is reduced. If the amount exceeds 5% by mass, the liberation rate of the inorganic fine powder is increased and the slipping from the blade increases, resulting in contamination of the charging member. It tends to be easy to do.

  The inorganic fine powder of perovskite crystal used in the present invention is obtained by adding strontium hydroxide to a titania sol dispersion obtained by adjusting the pH of a hydrous titanium oxide slurry obtained by hydrolyzing an aqueous solution of titanyl sulfate, for example. Then, it can be synthesized by heating to the reaction temperature. By setting the pH of the hydrous titanium oxide slurry to 0.5 to 1.0, a titania sol having a good crystallinity and a particle size can be obtained.

  For the purpose of removing ions adsorbed on the titania sol particles, it is preferable to add an alkaline substance such as sodium hydroxide to the dispersion of the titania sol. At this time, it is preferable that the pH of the slurry is not 7 or higher so that sodium ions and the like are not adsorbed on the surface of the hydrous titanium oxide. The reaction temperature is preferably about 60 ° C. to 100 ° C., and in order to obtain a desired particle size distribution, the temperature rising rate is preferably 30 ° C./hour or less, and the reaction time is 3 to 7 hours. preferable.

  In order to confirm that the crystal structure of the inorganic fine powder is a perovskite type (a face-centered cubic lattice composed of three different elements), it can be confirmed by performing X-ray diffraction measurement.

  The inorganic fine powder is preferably treated on the surface of the fine powder from the viewpoint of controlling the triboelectric charge polarity and the triboelectric charge amount depending on the environment in consideration of development characteristics.

  Further, by controlling (decreasing) the triboelectric charge amount and increasing the hydrophobicity by surface treatment, it is possible to reduce the adhesion to the charging member, and accordingly, the cleaning ability by the cleaning member is improved accordingly, which is preferable.

  Examples of the surface treatment agent include a treatment agent such as a coupling agent, silicone oil, and fatty acid metal salt.

  By performing the surface treatment, for example, in the case of a coupling agent that is a compound having a hydrophilic group and a hydrophobic group, the hydrophobic group side becomes the outer side by covering the surface of the inorganic fine powder with the hydrophilic group side. Thus, the fluctuation of the triboelectric charge amount due to the environment can be suppressed, and the triboelectric charge amount can be easily controlled by a coupling agent into which a functional group such as an amino group or fluorine is introduced.

  Furthermore, by treating the surface with the surface treatment agent as described above, the surface of the inorganic fine powder is reduced to fine particles such as fragments smaller than the free average particle diameter, which cause drum scratches contained in the inorganic fine powder. This is preferable because it has a supporting effect of fixing to the drum, and also has an effect of preventing drum scratches.

  Further, in the case of the surface treatment agent as described above, the shape of the inorganic fine powder is hardly changed because of the surface treatment at the molecular level, and the scraping force due to the cubic shape and the rectangular parallelepiped shape is maintained. It is more preferable.

  Examples of coupling agents include titanate, aluminum, and silane coupling agents. Examples of fatty acid metal salts include zinc stearate, sodium stearate, calcium stearate, zinc laurate, aluminum stearate, and magnesium stearate. The same effect can be obtained with stearic acid, which is a fatty acid.

  The treatment method includes dissolving and dispersing the surface treatment agent to be treated in a solvent, adding an inorganic fine powder therein, removing the solvent with stirring, a wet method, a coupling agent, and a fatty acid metal. Examples thereof include a dry method in which a salt and an inorganic fine powder are directly mixed and treated with stirring.

  Further, regarding the surface treatment, it is not necessary to completely treat and coat the inorganic fine powder, and the inorganic fine powder may be exposed as long as the effect is obtained. That is, the surface treatment may be formed discontinuously.

  It is preferable that the protective layer of the photoreceptor contains a fluorine resin powder. Inclusion of fluororesin powder increases the slipperiness of the surface of the photoconductor, reducing the load on the blade, reducing blade chipping and blade wear, and reducing adhesion to toner. Therefore, it is preferable because it has an effect on fusion.

  It is preferable that content of a fluororesin powder is 5-40 mass% in the mass of the whole protective layer. If it is 5% or less, the effect of slipperiness is hardly seen, the load on the blade increases and it becomes easy to squeeze, and if it is 40% or more, the effect of the curable resin is hindered, resulting in a decrease in film strength. Since the body is too slippery, the cleaning blade also slides on the photosensitive member, and it becomes difficult to remove the discharge products, particularly at the initial stage of durability, and image flow is likely to occur, which is not preferable. Furthermore, it is not preferable because fine inorganic fine powder slips through.

  Further, the surface roughness of the protective layer of the photoreceptor is preferably a surface roughness in the range of 0.1 to 1.5 μm in terms of ten-point average roughness RzJis. The rough surface is preferable because the contact area between the blade and the protective layer is reduced, so that the slipping property is increased, the load on the blade is reduced, and there is an effect of reducing the blade chipping or the blade itself.

  When Rzjis is less than 0.1 μm, there is almost no sliding effect, the load on the blade increases, and it becomes easy to squeeze, and when it exceeds 1.5 μm, not only inorganic fine powder but also toner slip-through occurs. Since it becomes easy to do, it is not preferable.

  Surface roughening methods include surface blasting and the addition of a roughening agent in the protective layer. By changing the revision of the wrapping tape, the surface roughness can be controlled easily and stably. The surface of the protective layer, which can be roughened, is preferably brought into contact with the surface of the protective layer by rotating the photosensitive member while the photoreceptor is driven to rotate.

  The surface ten-point average roughness Rzjis was measured based on JIS B0601 (2001) using Surfcoder SE-3500 (manufactured by Kosaka Laboratory) with a cut-off of 0.8 mm and a measurement length of 8 mm. .

  The charging member comprises at least an elastic layer that can be uniformly brought into contact with the photosensitive member, and a surface layer from the viewpoint of preventing dirt and oil from exuding from the elastic layer. Preferably contains a fluororesin.

  It is preferable to use a highly releasable fluororesin for the surface layer because the adhesion of the inorganic part powder is reduced, and the effect of scattering and removal by the brush cleaning member is increased.

  Examples of the present invention are specifically shown below, but are not limited thereto. First, examples of the photoreceptor, inorganic fine powder, toner, charging roller, and cleaning member used in the image forming method of the present invention are shown. In addition, the part in an Example represents a mass part.

(Photoreceptor Production Example 1)
An aluminum cylinder having a diameter of 30 mm × 357.5 mm is used as a support, and a paint composed of the following materials is applied to the support by a dip coating method and thermally cured at 140 ° C. for 30 minutes, and the film thickness is 18 μm. The conductive layer was formed.

Conductive pigment: SnO ₂ coated barium sulfate 10 parts Resistance adjusting pigment: Titanium oxide 2 parts Binder resin: Phenol resin 6 parts Leveling material: Silicone oil 0.001 part Solvent: Methanol, methoxypropanol 0.2 / 0.8 15 parts Next, a solution prepared by dissolving 3 parts of N-methoxymethylated nylon and 3 parts of copolymer nylon in a mixed solvent of 65 parts of methanol and 30 parts of n-butanol was applied by dip coating method on the resulting film. A 0.7 μm intermediate layer was formed.

  Next, 4 parts of hydroxygallium phthalocyanine having strong peaks at 7.4 ° and 28.2 ° of black angle 2θ ± 0.2 ° of CuKα characteristic X-ray diffraction, polyvinyl butyral (trade name: ESREC BX-1, Sekisui Chemical) 2 parts) and 80 parts of cyclohexanone were dispersed in a sand mill using 1 mm diameter glass beads for 4 hours, and then 80 parts of ethyl acetate was added to prepare a charge generation layer dispersion. This was applied by a dip coating method to form a charge generation layer having a thickness of 0.2 μm.

  Next, 7 parts of a styryl compound of the following structural formula

およびポリカーボネート樹脂（ユーピロンＺ８００、三菱エンジニアリングプラスチックス（株）社製）１０部をモノクロロベンゼン１０５部よびジクロロメタン３５部の混合溶媒中に溶解して調整した電荷輸送層用塗料を用いて、前記電荷発生層上に電荷輸送層を形成した４層の感光体を作製した。このときの電荷輸送層の膜厚は１５μｍであった。

And charge transport layer coating material prepared by dissolving 10 parts of polycarbonate resin (Iupilon Z800, manufactured by Mitsubishi Engineering Plastics Co., Ltd.) in a mixed solvent of 105 parts monochlorobenzene and 35 parts dichloromethane. A four-layer photoreceptor having a charge transport layer formed on the layer was prepared. At this time, the thickness of the charge transport layer was 15 μm.

  Next, the following structural formula

の正孔輸送性化合物４５部をｎ−プロピルアルコール５５部に溶解し、１９部のポリテトラフルオロエチレン微粒子（テフロン（登録商標）、デュポン社）を添加して高圧分散機（マイクロフルイタイザー、Ｍｉｃｒｏｆｌｕｉｄｉｃｓ社製）にて分散し、表面保護層用塗料を調製した。この塗料を用いて、前記電荷輸送層上に保護層を塗布したのち、酸素濃度１０ｐｐｍの雰囲気下で加速電圧１５０ＫＶ、線量５０ｋＧｙの条件で電子線を照射し、その後、同雰囲気下で感光体の温度が１５０℃になる条件下で５分間の加熱処理を行い、その後、通常雰囲気化で１４０℃で１時間の加熱乾燥を行い、膜厚４μｍの保護層を形成した電子写真感光体１を得た。

Of polytetrafluoroethylene (Teflon (registered trademark), DuPont) was added to a high-pressure disperser (microfluidizer, Microfluidics, Microfluidics). To prepare a coating material for the surface protective layer. Using this paint, a protective layer is applied on the charge transport layer, and then irradiated with an electron beam under the conditions of an acceleration voltage of 150 KV and a dose of 50 kGy in an atmosphere with an oxygen concentration of 10 ppm. An electrophotographic photosensitive member 1 having a protective layer having a thickness of 4 μm is obtained by performing a heat treatment for 5 minutes under the condition of a temperature of 150 ° C., and then performing heat drying for 1 hour at 140 ° C. in a normal atmosphere. It was.

(Photoreceptor Production Example 2)
In Photoconductor Production Example 1, a coating material for the surface protective layer was prepared by the following procedure.

  32 parts of a hole transporting compound having the structural formula shown below,

下記構造式、８部を

The following structural formula, 8 parts

モノクロロベンゼン５０部およびジクロロメタン５０部の混合溶媒中に溶解し保護層用塗料を調製した。

A protective layer coating material was prepared by dissolving in a mixed solvent of 50 parts of monochlorobenzene and 50 parts of dichloromethane.

  This coating solution was coated on the four-layered photoreceptor prepared in photoreceptor preparation example 1 to prepare photoreceptor 2 in the same manner as photoreceptor 1 except that the film thickness was 3 μm.

(Photoreceptor Production Example 3)
In Photoconductor Production Example 1, the dose of electron beam was set to 25 kGy, and the same photoconductor 3 as in Photoconductor Production Example 1 was obtained except that heating after irradiation was not performed.

(Photoreceptor Production Example 4)
A No. 3000 wrapping tape affixed on an elastic roller was brought into contact with the surface of the protective layer of the photoreceptor 1 to obtain a photoreceptor 4 whose surface was roughened while rotating the photoreceptor.

(Photoreceptor Production Example 5)
A photoconductor 5 similar to the photoconductor 4 was obtained except that the number of wrapping tapes was changed to No. 300 in Photoconductor Production Example 4.

(Photoreceptor Production Example 6)
A photoconductor 6 similar to the photoconductor 1 was obtained except that the amount of polytetrafluoroethylene fine particles added was 1 part in Photoconductor Production Example 1.

(Photoreceptor Production Example 7)
A photoconductor 7 similar to the photoconductor 1 was obtained except that the amount of polytetrafluoroethylene fine particles added was 37 parts in Photoconductor Production Example 1.

  The following table shows the values of elastic deformation rate, Hu, and surface roughness Rzjis of the photoreceptors 1 to 7.

(Production Example 1 of Perovskite Type Inorganic Fine Powder)
The hydrous titanium oxide obtained by hydrolyzing the titanyl sulfate aqueous solution was washed with pure water until the electric conductivity of the filtrate reached 2200 μS / cm. NaOH was added to the hydrous titanium oxide slurry, and the sulfate radical adsorbed was washed with SO ₃ until it became 0.24% by mass. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH of the slurry to 1.0 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion, the pH of the dispersion was 6.0, and the supernatant was washed by decantation with pure water until the electrical conductivity of the supernatant reached 120 μS / cm. When the obtained hydrous titanium oxide was examined by X-ray diffraction, only the peak of anatase TiO ₂ was shown.

533 g (0.6 mol) of metatitanic acid having a moisture content of 91% obtained as described above was put into a SUS reaction vessel, and nitrogen gas was blown into the vessel and left for 20 minutes to replace the inside of the reaction vessel with nitrogen gas. 183.6 g (0.66 mol) of Sr (OH) 2.8H ₂ O (purity 95.5%) was added, and distilled water was further added to add 0.3 mol / liter (SrTiO ₃ equivalent), SrO / TiO _2. The slurry was adjusted to a molar ratio of 1.10.

  The slurry was heated to 90 ° C. at 18 ° C./1 hour in a nitrogen atmosphere, and reacted at the boiling point for 3 hours. After the reaction, the reaction solution is cooled to 40 ° C., the supernatant is removed under a nitrogen atmosphere, and the operation of adding 2.5 liters of pure water and decanting is repeated twice, followed by filtration with Nutsche. It was. The obtained cake was dried in the atmosphere at 110 ° C. for 4 hours.

  The obtained strontium titanate had an average primary particle size of 150 nm and a particle shape of cubic and / or rectangular parallelepiped, and the content ratio was 70% by number. This strontium titanate is designated as inorganic fine powder A-1.

(Production Examples 2 to 5 of perovskite type inorganic fine powder)
In Production Example 1, the reaction temperature of strontium titanate, the temperature rise rate to the temperature, the reaction time, and the pH of the dispersion were adjusted to produce a perovskite inorganic fine powder having the following characteristics. The following table summarizes.

(Production Example 6 of Perovskite Type Inorganic Fine Powder)
100 parts of inorganic fine powder A-2 is added to an aqueous solution of sodium stearate that is a fatty acid metal salt (7 parts of sodium stearate and 100 parts of water), and an aqueous aluminum sulfate solution is added dropwise with stirring to produce inorganic fine powder A- Inorganic fine powder A-4 was prepared by precipitating and adsorbing aluminum stearate on the surface of No. 2 and treating the surface. The average particle diameter of A-4 was 90 nm, and the number% of cubic and / or rectangular parallelepiped was 70%.

(Toner particle production example 1)
Styrene acrylic resin 100 parts (styrene-butyl acrylate copolymer ratio = 78: 22)
・ 100 parts of magnetic material ・ 2 parts of salicylic acid metal compound ・ 3 parts of paraffin wax The above components are mixed using a Henschel mixer, melt kneaded using a twin-screw extrusion kneader, coarsely pulverized using a hammer mill, and finely pulverized using a jet mill. Thereafter, classification was performed to obtain colored particles X (toner particles) having an average particle diameter of 7 μm.

(Toner Production Examples 1 to 6)
100 parts of toner particles X, 100 parts of silica having a primary particle size of about 7 nm, 1.2 parts of hydrophobic silica (BET = 130 m ^{2 /} g) surface-treated with 20 parts of dimethyl silicone oil, inorganic fine powders A-1, 2, 3, 4 and B-1, 2 were added externally by 1.5 parts Henschel mixer FM10B, respectively, to obtain toners C-1 to C-6.

(Toner Production Examples 7 to 9)
As in Toner Production Example 1, Toners C7 to C9 were obtained in the same manner as in Production Example 1 except that the amount of inorganic fine powder A-4 added was 0.04, 3.0, and 6.0 parts.

(Charging roller example 1)
The charging roller 1 in which tin oxide was dispersed was used for the surface layer mounted on GP405 manufactured by Canon Inc.

(Charging roller 2)
As a surface layer, a charging roller 2 in which tin oxide was dispersed in a fluororesin in the same amount as that of the charging roller 1 was used.

(Brush cleaning member)
As the fibers of the brush, the fiber 1 treated with copper sulfide on the surface of the acrylic resin fiber and the acrylic resin fiber 2 in which carbon is dispersed are prepared, the fiber diameter is adjusted, and the flocked portion is adjusted (for example, a brush for forming one bundle). For example, adjusting the spacing between the positions for flocking, and the like, and preparing brush members having the following fiber diameter and fiber density.

<Examples 1 to 26, Comparative Examples 1 to 11>
As an image forming apparatus for carrying out the image forming method of the present invention, an organic photoconductor digital copying machine using a laser beam (manufactured by Canon Inc .: GP405) was prepared. The outline of the apparatus includes a charging roller as a charging unit for the photosensitive member, a holding member for holding a cleaning member for cleaning the charging roller, and a non-woven pad member as a cleaning member, and development on the photosensitive member as a developing unit. A one-component developing device that employs a one-component jumping development method in which the agent and the photosensitive member are not in contact with each other, a charging roller as a transfer means, a blade cleaning means, and a pre-charging exposure means. Further, the photosensitive member charger, the cleaning unit, and the photosensitive member are integrated units. The process speed is 210 mm / s. The device was modified as follows.

  At the cleaning mechanism portion of the charging roller, the cleaning member provided with the holding member that holds the cleaning member is removed, and the brush member shown above is adjusted and attached to the holding member (the tip of the brush contacts the charging roller) 7), and a member that allows the reciprocating movement of the holding member provided with the cleaning member to the flange portion of the photosensitive member is always engaged, and the flange shape is further adjusted (the cam portion of the flange). The height of the crest is adjusted) to change to the image forming method in which the reciprocating distance of the brush cleaning member of the member holding the cleaning member is adjusted.

  Evaluation was performed using the image forming apparatus according to the following evaluation method.

Evaluation 1)
A strontium titanate adhering to the charging roller was used using a charging roller that was subjected to intermittent durability of 5,000 sheets with an A4 image at a printing rate of 6% using the above image forming apparatus in an environment of 30 ° C./80%. The amount of adhesion was measured by minute fluorescent X-rays. Micro fluorescent X-rays use EDAX Co., Ltd. Eagle-II, and measure atomic% of TiK line derived from additive strontium titanate and SnL line derived from tin oxide contained in the surface layer of the charging roller. Evaluation was performed with the value of the ratio (% Ti / Sn). That is, if the amount of adhesion is large, Ti increases and Sn decreases and the value increases. The measurement was performed by measuring three points in the longitudinal direction of the charging roller (near the center and both ends of the image area) and measuring the average value for evaluation.
◎: 0 or more and less than 0.2 ○: 0.2 or more and less than 0.4 ○ △: 0.4 or more and less than 0.6 Δ: 0.6 or more and less than 1.0 ×: 1.0 or more

Evaluation 2)
The cleaning blade, the developing device, and the transfer roller were removed, and only the photosensitive member, the charging roller, and the charging roller cleaning member were mounted, and continuous idle rotation for 40 hours was performed. The brush tear was evaluated according to the following evaluation items. .
◎: No tearing is observed. ○: One or more torn brushes and less than ten. ○ △: Ten torn brushes and not more than 50. △: Torn brushes are not less than 50 and less than 100. ×: Broken brush. 100 or more

Evaluation 3)
Endured 100,000 sheets of 10% A4 horizontal paper in 30 ° C / 80% environment and left the charging roller alone in a 23 ° C / 5% environment for 48 hours, and then cleaned the surface of the charging roller with a cleaning wiper. Using a Dasper (made by Ozu Sangyo Co., Ltd.) and cleaning with a dry wipe, and replacing the photoconductor with an unused photoconductor of the GP405 product in a 23 ° C / 5% environment. The applied DC voltage for primary charging is almost the same as the DC voltage for development, and without halftone density image (analog halftone) is produced without image exposure and charging unevenness due to damage to the charging roller surface. Were evaluated according to the evaluation items.
A: Analog halftone, no streak or uneven charging failure occurred, and a uniform image was obtained.
○: A slight streak-like charging failure occurred in the analog halftone, but an image having no problem in a normal halftone image was obtained.
Δ: A streak-like charging failure occurred in the analog halftone, and a slight streak-like charging failure occurred even in a normal halftone image.
X: A streaky or uneven charging failure occurred in the analog halftone, and a fogging image due to a charging failure occurred in a normal halftone image or a solid white image.

Evaluation 4)
A drum that had an endurance of 70,000 sheets of 2% A4 horizontal paper with an image ratio of 2% in a 23 ° C / 5% environment and 50,000 sheets of an A2 horizontal paper with an image ratio of 2% in a 32 ° C / 85% environment. The sheet was endured, and a hiragana character image having a size of 1 mm ² and a dot image having a size of 100 μm ² were drawn. The image was observed using a 50 × optical microscope and evaluated according to the following evaluation items. .
A: Both characters and dots are reproduced.
○: The character is reproduced, but the dot is slightly blurred and blurred △: The character is slightly blurred, blurred, and the dot is hardly reproduced ×: The character and the dot are not reproduced, and the character can be read No level.

Evaluation 5)
Durability of 50,000 sheets of A4 horizontal continuous paper with an image ratio of 2% in a 30 ° C./80% environment was evaluated, and the fused image was evaluated according to the following evaluation items.
A: Almost no fusing is observed on the photoreceptor and the image. O: A slight occurrence is observed on the photoreceptor, but a good image having no problem on the image is obtained.
(Triangle | delta): Generation | occurrence | production was confirmed on the photoconductor and the image was also a grade which is slightly seen with a halftone.
×: Confirmed as raining on a solid black image

Evaluation 6)
The surface roughness Rzjis of the drum that was durable in Evaluation 4 was measured, and the surface roughness after the initial and durability was compared, and the evaluation was performed according to the following evaluation items. The surface ten-point average roughness Rzjis is measured based on JIS B0601 (2001) using Surfcoder SE-3500 (manufactured by Kosaka Laboratory) with a cut-off of 0.8 mm and a measurement length of 8 mm. It was.
A: Rzjis is less than 0.5 μm in roughness after initial and durability R: Rzjis is more than 0.5 μm and less than 1.0 μm in roughness after initial and durability Δ: Roughness after initial and after durability Difference Rzjis is 1.0 μm or more and less than 2.0 μm ×: Rzjis is 2.0 μm or more in difference between roughness after initial and durability

  The following table shows the toner, drum, charging roller, charging roller cleaning member, moving distance of the cleaning member, and crossing angle α when the cleaning member abuts, used in Examples and Comparative Examples.

  The evaluation results of Examples and Comparative Examples are shown below.

1 is a diagram illustrating an example of a specific image forming apparatus of the present invention. 1 is a diagram illustrating an example of a specific image forming apparatus of the present invention. It is a figure which shows the contact method of the cleaning member to a charging member. It is a figure which shows an example of the cleaning member of a charging member. It is a figure which shows an example of the cleaning member of a charging member. It is a figure which shows an example of the cleaning member of a charging member. It is a figure which shows an example of the cleaning member of a charging member. It is a figure which shows an example of the cleaning member of a charging member. It is a figure which shows an example of a film | membrane characteristic output chart. It is a figure which shows an example of the film | membrane characteristic measurement of a photoreceptor protective layer. It is the schematic of the long side and short side in the particle size measurement of inorganic fine powder. It is a figure which shows an example of the electron micrograph (50,000 times) of inorganic fine powder. It is a figure which shows the point evaluated by the relationship between the particle size of inorganic fine powder, the fiber diameter of a cleaning member, and fiber density, and an Example and a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 6 Primary charging roller 7 Developing device 7-1 Developing sleeve 7-2 Developer stirring device 8 Transfer charging roller L Laser light L
DESCRIPTION OF SYMBOLS 3 Fixing device 4 Cleaning elastic blade 2 Frame body 5 Transfer material 9 Primary charging roller cleaning member 9-1 Fur brush roller type cleaning member 9-2 Pad brush type cleaning member 9-3 Brush sheet type cleaning member

Claims (15)

A step of bringing a rotatable charging member into contact with a photosensitive member having a photosensitive layer and a protective layer on the support and charging, an electrostatic latent image forming step of forming an electrostatic latent image on the charged photosensitive member, and toner carrying A development process for transferring the toner carried on the body to the electrostatic latent image for visualization, and a toner image formed on the photosensitive body is transferred to a transfer material with or without an intermediate transfer body. In an image forming method comprising a transfer step, a transfer step for electrostatic transfer to a transfer material, and a cleaning step for removing residual transfer toner remaining on the photoreceptor after the transfer step from the photoreceptor.
The universal hardness value HU of the photoreceptor surface is 150 or more and 240 or less (N / mm ² ), and the elastic deformation rate is 44% or more and 65% or less,
The toner includes toner particles having at least a binder resin and a colorant, and a perovskite crystal inorganic fine powder having a cubic and / or rectangular parallelepiped shape and an average primary particle diameter of 80 nm to 220 nm. A toner having at least
A cleaning member is provided for cleaning the charging member. The cleaning member contacts the charging member at least during image formation, and a portion in contact with the charging member reciprocates in the longitudinal direction of the charging member. When the average particle size of primary particles of the inorganic fine powder of the perovskite crystal is d (μm), the fiber density F of the brush (fibers / 10 mm) and the fiber diameter D (μm) are expressed by the following formula: An image forming method characterized by being in the range.
−2300 × d + 680 ≦ F ≦ −4500 × d + 1350 and 200 × d ≦ D ≦ 600 × d 2. The image forming apparatus according to claim 1, wherein the brush in the portion of the cleaning member that is in contact with the charging member has a reciprocating movement distance T (mm) in the longitudinal direction of the charging member within a range of the following formula. Method.
2.5 / d ≧ T (mm) ≧ 0.2 / d 3. The image forming method according to claim 1, wherein the axis of the cleaning member is in contact with the rotation axis of the charging member at a predetermined crossing angle α which is in the range of the following expression.
0.01 / d ≦ α (°) ≦ 0.4 / d   The image forming method according to claim 1, wherein the brush fiber of the cleaning member is subjected to a surface treatment.   The image forming method according to claim 1, wherein the cleaning member has a sheet shape.   The image forming method according to claim 1, wherein the inorganic fine powder contains 60% by number or more of particles having a cubic shape and / or a rectangular parallelepiped shape.   The image forming method according to claim 1, wherein the content of the inorganic fine powder in the toner is 0.05% by mass to 5.0% by mass.   The image forming method according to claim 1, wherein the inorganic fine powder is strontium titanate or barium titanate.   The image forming method according to claim 1, wherein the inorganic fine powder is subjected to a surface treatment.   The image forming method according to claim 1, wherein the protective layer of the photoconductor contains a fluorine resin powder.   The image forming method according to claim 10, wherein the content of the fluororesin powder contained in the protective layer is 5 to 40% by mass in the mass of the entire protective layer.   12. The image forming method according to claim 1, wherein a ten-point average roughness Rzjis of the surface roughness of the protective layer of the photoreceptor is 0.1 to 1.5 μm.   While the surface of the protective layer of the photoconductor is driven to rotate, the surface of the protective layer is roughened by bringing a wrapping tape of No. 500 to 4000 into contact with the surface of the protective layer. The image forming method according to claim 12.   The charging member comprises at least two layers of a conductive or medium resistance elastic layer formed on a conductive substrate and a surface layer, and the surface layer contains at least a fluororesin. The image forming method according to claim 1.   The image forming method according to claim 1, wherein the charging member is a roller-type charging member that is driven to rotate by rotation of the photosensitive member.

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