JP5403347B2 - Electrophotographic photosensitive member, image forming apparatus using the same, and process cartridge for the apparatus - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive member having high durability and capable of maintaining high image quality over a long period of time. In particular, the present invention relates to a photoreceptor having good surface characteristics of the photosensitive layer and good cleaning properties. The present invention also relates to an image forming apparatus using the photoreceptor and a process cartridge for the image forming apparatus.

In recent years, an organic photosensitive layer containing an organic photoconductive material on a support as an electrophotographic photosensitive member (hereinafter also simply referred to as “photosensitive member” or “image carrier”) mounted on a laser printer or a digital copying machine. A photoconductor provided with is generally used. Among them, a multilayer organic photoreceptor in which a charge generation material and a charge transport material are contained in separate layers is mainly used. This is due to cost, productivity, and freedom of material design.
Since these electrophotographic photoreceptors are exposed to mechanical external force, electrical or chemical hazards in the electrophotographic image forming process, they undergo various deteriorations. In particular, recently, the output of color images has increased, and electrophotographic organic photoreceptors that are used repeatedly over a long period of time are required to have durability against these deteriorations more than ever.

  For mechanical durability, a toner mainly composed of a colorant and a resin is used during development, and a developer containing hard inorganic fine particles is used as an additive, and a hard fiber or clay additive is included during transfer. Abrasion progresses because it is strongly pressed against the paper and rubbed, or because it is slid strongly by the cleaning blade during cleaning. For this reason, polycarbonate, polyarylate or the like having high durability is used as the binder resin for the organic photoreceptor. (See Japanese Patent No. 2520270 of Patent Document 1 and Japanese Patent No. 3585197 of Patent Document 2).

  Conventionally, various improvements in the mechanical durability have been proposed in which a protective layer is provided on the surface of the photoreceptor. As this protective layer, a protective layer in which hard metal oxide fine particles are dispersed or a protective layer obtained by crosslinking and curing has been studied (see JP 2001-166521 A). Further, studies have been made to improve the lubricity of the surface of the photoconductor to prevent the film from being scraped off, and its practical application has been advanced (Japanese Patent Publication No. 6-82221 of Patent Document 4 and Japanese Patent Application Laid-Open No. 2002-2002 of Patent Document 5). (See 196523)

As described above, with the increase in output of color images in recent years, higher image quality is required than ever before, but in particular, the cleaning performance of residual toner remaining on the photoconductor for each image formation is higher than before. I found out that it was required. This is due to the fact that a photoconductor with a certain degree of wear durability has been realized but is still unsatisfactory. In long-term repeated image formation, small scratches and cracks may occur on the surface of the photoconductor, and the surface of the photoconductor slides with the tip of a hard blade for cleaning, so the blade is chipped and fine toner May slip through. In particular, when the latter occurs, black streaks appear in the image and the image quality deteriorates at a stroke. Image degradation due to toner slipping has become an urgent issue for highly durable photoreceptors.
The largest cause of abrasion on the surface of the photoreceptor is the cleaning blade. However, if the transferability of the toner can be improved, residual toner is reduced, pressure applied to the cleaning blade can be reduced, and chipping of the blade can be advantageously suppressed. In Japanese Patent Application Laid-Open No. 2001-66814 of Patent Document 6, an irregular portion having a specific shape such as a prism shape, a wave shape, a cone shape, a pyramid shape, or a well shape is formed on the surface of the photoreceptor by a touch roll or a stamper. However, studies have been made to increase the releasability of the toner. Further, there is a description that filler particles containing silicon and fluorine are contained in all layers of the charge transport layer to reduce the toner transfer rate and the stress applied to the photoreceptor. However, the photoconductor having the concavo-convex shape in this study, when repeatedly forming an image, the edge of the cleaning blade may be chipped off when the frictional resistance of the photoconductor surface increases. Therefore, there was toner slipping.

  Recently, a method for producing a photoconductor for transferring a fine uneven shape onto the surface of the photoconductor has been proposed in Japanese Patent Application Laid-Open No. 2007-233356. A concave shape having reproducibility is formed on the surface layer by performing molding while maintaining the glass transition point temperature of the charge transport layer, the temperature of the mold, and the temperature of the support in a specific relationship. Japanese Patent No. 3963473 of Patent Document 8 describes a method of roughening the surface of the photoreceptor by irradiating the surface layer of the photoreceptor with laser light and forming a plurality of recesses in the surface layer. ing. As a result of examining these, it is said that a resistance adjusting material may be contained in the protective layer, but a residue due to laser light remains in the hole and is not easily discharged, which is not preferable because it interferes with image formation.

  In Japanese Patent Application Laid-Open No. 2007-233359 of Patent Document 9, a study is made to improve the cleaning property by forming a plurality of specific concave portions on the surface of the photoreceptor. The concave hole has a specific major axis diameter and minor axis diameter and depth, and the concave part is present in the surface layer with a specific surface density. It prevents scratches on the surface that grows due to external forces acting in the image forming process such as a cleaning blade. However, there may be a case where a small black spot appears when image formation is repeated due to clogging of the developer additive in the recess. In addition, the formation of the recesses on the surface of the photoreceptor by the conventional laser or mold does not make a difference that fine holes are formed in the surface layer at high density, and the surface layer itself is mechanically brittle.

  Japanese Patent Application Laid-Open No. 2005-99688 of Patent Document 10 describes that a photosensitive material surface containing a specific curable resin as a binder resin and an organic or inorganic filler. Proposals have been made to contain carbon fine particles, fluororesin fine particles, silicone resin fine particles, diamond-like carbon, or inorganic fillers such as silicon oxide and titanium oxide. Certainly, the curable binder resin in the present invention has higher wear resistance than the conventional resin matrix, and is effective in preventing the filler from being dug up during the image forming operation. However, if a large amount of fine particles are contained, it may be colored and the light transmittance tends to be insufficient. Or, since the organic filler is soft, the durability originally required is insufficient. Since the inorganic filler is hard, when it comes out of the surface, it becomes a large local resistance against the sliding of the elastic blade for cleaning, and the blade chipping may occur, resulting in poor cleaning. Even if the filler content is reduced, these cannot be eliminated at all as long as the filler is present. That is, there is room for improvement in the presence of the filler itself.

In Japanese Patent Application Laid-Open No. 7-92697 of Patent Document 11, there is a proposal that there is an effect similar to the case where a filler is contained even if there is no filler. In this method, after forming the outermost surface of the organic photoreceptor, the outermost surface forming coating solution is diluted and coated with a spray gun to form an uneven portion having a specific range of curvature on the surface. Although the inversion of the cleaning blade is prevented and the edge defect is improved, there is room for improvement in terms of mechanical durability of the convex portion.
As described above, in the conventional technique, it is difficult to achieve both cleanability and stability over time. In addition, when a shape is imparted to the surface of the photoreceptor, a problem of image non-uniformity also occurs.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide an electrophotographic photoreceptor excellent in cleaning properties. In particular, an electrophotographic photosensitive member capable of suppressing chattering, twisting, and reversal of the cleaning blade and preventing toner from slipping through the cleaning blade and causing poor cleaning, and further having excellent image quality uniformity is provided. For the purpose.

In the electrophotographic photosensitive member having a cross-linked surface layer, the inventors have formed a convex portion on the surface layer, and the surface layer and the convex portion have the same charge transport. A structural part (structural part (B)) containing a cross-linked product containing a structural unit having a structural structure (structural unit (A)) and having no charge transporting structure with the structural unit (A) ), The content of the structural unit (A) is higher than that of the surface layer, and the structural part (A) is 90 wt% with respect to the total weight of the structural part (A) and the structural part (B). When the surface roughness of the surface layer after forming the convex portion is expressed in RzJIS, it can be solved by having a plurality of independent convex portions having a height of 1/2 × RzJIS or higher. And the present invention was completed.
Furthermore, this invention includes what is provided with the structure as described below.
(2). The electrophotographic photosensitive member as described in (1) above, wherein the height of the convex portion is 6 μm or less as an average value with respect to a measurement length of 12 mm.
(3). The electrophotographic photosensitive member according to item (1) or (2), wherein the surface layer has a concave portion, and the convex portion is formed thereon.
(4). Item (1) to (3), wherein the structural unit (A) is derived from a radical polymerizable compound having a site of the charge transporting structure and one or more radical polymerizable functional groups. The electrophotographic photosensitive member according to any one of the items).
(5). The structural part (B) is mainly derived from a radical polymerizable material having no charge transport structure and having two or more radical polymerizable functional groups. The electrophotographic photosensitive member according to any one of (4).
(6). The electrophotographic photosensitive member according to any one of (1) to (5), wherein the structural unit (A) having the charge transporting structure is a triarylamine structure.
(7). Item (1) to Item (6), wherein the crosslinked body is formed by crosslinking a coating solution containing at least a radical polymerizable triarylamine compound represented by the following general formula (1). The electrophotographic photosensitive member according to any one of the above;

(Wherein, d, e and f are each an integer of 0 or 1, R ₁₃ represents a hydrogen atom or a methyl group, R ₁₄ and R ₁₅ represent a substituent other than a hydrogen atom, and a plurality of cases may be different. G and h each represent an integer of 0 to 3. Z is a single bond, a methylene group, an ethylene group,
Or

を表す。）。

Represents. ).

(8). The electrophotographic photoreceptor as described in (7) above, wherein the substituents R ₁₄ and R ₁₅ are alkyl groups having 1 to 6 carbon atoms.
(9). The electrophotographic photosensitive member according to any one of (1) to (8), wherein the convex portion is formed by a spray coating method.
(10). Any of (1) to (9) above, wherein the photosensitive layer of the electrophotographic photosensitive member has a laminated structure of an undercoat layer, a charge generation layer, a charge transport layer, and a surface layer from the support side. The electrophotographic photosensitive member described.
(11). In the method for producing an electrophotographic photoreceptor having a cross-linked surface layer, the photoreceptor has a convex portion on the surface layer, and the surface layer and the convex portion have the same charge transporting structure. A cross-linked product containing a structural unit (A) is contained, and the convex part includes a structural part (B) having no charge transporting structure in addition to the structural unit (A), and the structural unit (A) Is higher than the surface layer, and the structural part (A) is less than 90 wt% with respect to the total weight of the structural part (A) and the structural part (B), and after the formation of the convex part When the surface roughness of the surface layer is represented by RzJIS, the number of convex portions having a height of ½ × RzJIS or more is 30 or more and 300 or less per 12 mm measurement length, and the convex portions are convex. Having a step of forming on the surface layer by spray coating a coating liquid for forming a part A method for producing an electrophotographic photosensitive member characterized by the above.
(12). Item (11), wherein the coating liquid contains a radical polymerizable compound that generates the structural unit (A) and a radical polymerizable material that mainly generates the structural part (B). A process for producing an electrophotographic photoreceptor according to 1.
(13). The method for producing an electrophotographic photosensitive member according to item (11) or (12), further comprising a step of forming a cross-linking convex portion by UV irradiation after the spray coating.
(14). An image forming apparatus that forms an image by sequentially repeating at least charging, exposure, development, transfer, and cleaning steps, wherein the image forming apparatus is described in any one of (1) to (10) above. An image forming apparatus comprising an electrophotographic photosensitive member.
(15). In the image forming apparatus, the image forming apparatus according to the item (14), wherein polymerized toner is used in the developing step.
(16). The image forming apparatus according to (14) or (15), wherein the image forming apparatus includes means for scraping zinc stearate with a brush-like roller and inputting the zinc stearate to the electrophotographic photosensitive member.
(17). The image forming apparatus according to any one of (14) to (16), wherein the image forming apparatus has a developing station of at least two colors and is a tandem type and further develops using polymerized toner. .
(18). In the process cartridge detachable from the main body of the image forming apparatus including at least the photosensitive member, the developing unit, and the cleaning unit, the photosensitive member is the electrophotographic photosensitive member according to any one of the items (1) to (10). A process cartridge for an image forming apparatus.

  According to the present invention, it is possible to provide an electrophotographic photosensitive member having a surface layer having a rough surface with a suitable convex portion having high durability. Therefore, it is possible to provide a high-performance and highly reliable image forming process, an image forming apparatus, and a process cartridge for an image forming apparatus that can provide a good image over a long period of time by using this photoconductor.

It is sectional drawing which shows the layer structure of the electrophotographic photoreceptor which concerns on this invention. It is sectional drawing which shows another layer structure of the electrophotographic photoreceptor which concerns on this invention. It is a conceptual diagram of the photoconductor which has a convex part on the surface of the photosensitive layer of this invention. FIG. 3 is a plan view of the surface of a photoreceptor in which irregularly shaped convex portions of the present invention are randomly arranged. It is a figure explaining the definition of the height of the convex part in this invention. It is a conceptual diagram of the spray coating apparatus for forming a convex part in this invention. 1 is a schematic cross-sectional view showing an example of an image forming apparatus according to the present invention. FIG. 6 is a schematic cross-sectional view showing another example of the image forming apparatus according to the present invention. FIG. 6 is a schematic cross-sectional view showing still another example of the image forming apparatus according to the present invention. FIG. 6 is a schematic cross-sectional view showing still another example of the image forming apparatus according to the present invention. FIG. 6 is a schematic cross-sectional view showing still another example of the image forming apparatus according to the present invention. FIG. 6 is a schematic cross-sectional view showing still another example of the image forming apparatus according to the present invention. 1 is a configuration diagram of a surface roughness / contour shape measurement system. FIG. 3 is a schematic cross-sectional view showing a means for supplying zinc stearate to the photoreceptor in the image forming apparatus of the present invention. Sectional curve measured by roughness meter of Example 1 FIG. 3 is a diagram showing a three-dimensional image by the laser microscope of Example 1.

[Electrophotographic photoreceptor]
Hereinafter, the electrophotographic photosensitive member of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view schematically showing an example of an electrophotographic photoreceptor having still another layer structure of the present invention. A charge generation layer (25) and a charge transport layer (on a conductive support (21)) are shown. 26) and a cross-linked resin surface layer (28).
FIG. 2 is a cross-sectional view schematically showing an example of an electrophotographic photosensitive member having still another layer structure of the present invention, and an undercoat layer between the conductive support (21) and the charge generation layer (25). (24) is provided, and a charge transport layer (26) and a crosslinked resin surface layer (28) are provided on the charge generation layer (25).

[Conductive support]
Examples of the conductive support (21) include those having a volume resistance of 10 ¹⁰ Ω · cm or less, such as metals such as aluminum, nickel, chromium, nichrome, copper, silver, gold, platinum, iron, tin oxide, A film or cylindrical plastic or paper coated with an oxide such as indium oxide by vapor deposition or sputtering, or a plate made of aluminum, aluminum alloy, nickel, stainless steel, or the like, and a drawing ironing method, impact It is possible to use a tube that has been surface-treated by cutting, superfinishing, polishing, or the like after being made into a bare pipe by a method such as the Ironing method, the Extruded Ironing method, the Extracted Drawing method, or the cutting method.

[Underlayer]
In the electrophotographic photoreceptor used in the present invention, an undercoat layer (24) can be provided between the conductive support and the photosensitive layer. The undercoat layer (24) is provided for the purpose of improving adhesiveness, preventing moire, improving the coatability of the upper layer, and preventing charge injection from the conductive support.
The undercoat layer usually contains a resin as a main component. Usually, since the photosensitive layer is applied on the undercoat layer, the resin used for the undercoat layer is preferably a thermosetting resin that is hardly soluble in an organic solvent. In particular, polyurethane, melamine resin, and alkyd-melamine resin are particularly preferable materials because many of them sufficiently satisfy the above purpose. The resin can be used as a coating material which is appropriately diluted with a solvent such as tetrahydrofuran, cyclohexanone, dioxane, dichloroethane, butanone and the like.

In addition, fine particles such as metal or metal oxide may be added to the undercoat layer in order to adjust conductivity and prevent moire. In particular, titanium oxide is preferably used.
The fine particles are dispersed in a ball mill, attritor, sand mill or the like using a solvent such as tetrahydrofuran, cyclohexanone, dioxane, dichloroethane, or butanone to obtain a coating material in which the dispersion and the resin component are mixed.
The undercoat layer is formed on the support by dip coating, spray coating, bead coating, or the like. If necessary, it is formed by heat curing.
In many cases, the thickness of the undercoat layer is suitably about 2 to 5 μm. When the accumulation of the residual potential of the photoconductor becomes large, it is preferable to set it to less than 3 μm.

  The photosensitive layer in the present invention is preferably a laminated photosensitive layer in which a charge generation layer and a charge transport layer are sequentially laminated.

[Charge generation layer]
Of the layers in the multilayer photoreceptor, the charge generation layer (25) will be described. The charge generation layer (25) indicates a part of the laminated photosensitive layer and has a function of generating charges by exposure. This layer is mainly composed of a charge generating substance among the contained compounds. For the charge generation layer, a binder resin may be used as necessary. As the charge generation material, inorganic materials and organic materials can be used.
Examples of the inorganic material include crystalline selenium, amorphous selenium, selenium-tellurium, selenium-tellurium-halogen, selenium-arsenic compound, 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 or phosphorus atoms are preferably used.

  On the other hand, as the organic material, known materials can be used, for example, metal phthalocyanines such as titanyl phthalocyanine and chlorogallium phthalocyanine, metal-free phthalocyanines, azulenium salt pigments, squaric acid methine pigments, and symmetrical types having a carbazole skeleton. Alternatively, an asymmetric azo pigment, a symmetric or asymmetric azo pigment having a triphenylamine skeleton, a symmetric or asymmetric azo pigment having a fluorenone skeleton, a perylene pigment, and the like can be given. Among these, metal phthalocyanines, symmetric or asymmetric azo pigments having a fluorenone skeleton, symmetric or asymmetric azo pigments having a triphenylamine skeleton, and perylene pigments have a high quantum efficiency of charge generation, and thus are suitable for the present invention. It is suitable as a material to be used. These charge generation materials may be used alone or as a mixture of two or more.

  Binder resins used as necessary for the charge generation layer include polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, polyarylate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N- Examples thereof include vinyl carbazole and polyacrylamide. Moreover, the polymeric charge transport material mentioned later can also be used. Of these, polyvinyl butyral is often used and is useful. These binder resins may be used alone or as a mixture of two or more.

Methods for forming the charge generation layer are roughly classified into a vacuum thin film preparation method and a casting method from a solution dispersion system.
Examples of the former method include a vacuum deposition method, a glow discharge decomposition method, an ion plating method, a sputtering method, a reactive sputtering method, and a CVD (chemical vapor deposition) method. Can be formed satisfactorily.
In addition, in order to provide the charge generation layer by the casting method, the above-described inorganic or organic charge generation material is mixed with a binder resin, if necessary, using a solvent such as tetrahydrofuran, cyclohexanone, dioxane, dichloroethane, butanone, ball mill, attritor. The dispersion may be dispersed by a sand mill or the like, and the dispersion may be diluted appropriately. Among these solvents, methyl ethyl ketone, tetrahydrofuran, and cyclohexanone are preferable because they have a lower environmental impact than chlorobenzene, dichloromethane, toluene, and xylene. The application can be performed by a dip coating method, a spray coating method, a bead coating method, or the like.
The thickness of the charge generation layer provided as described above is usually about 0.01 to 5 μm.
When it is necessary to reduce the residual potential and increase the sensitivity, these characteristics are often improved by increasing the thickness of the charge generation layer. On the other hand, the chargeability often deteriorates, such as the charge charge retention and space charge formation. From these balances, the thickness of the charge generation layer is more preferably in the range of 0.05 to 2 μm.

  Further, if necessary, low-molecular compounds such as antioxidants, plasticizers, lubricants and ultraviolet absorbers and leveling agents described later can be added to the charge generation layer. These compounds can be used alone or as a mixture of two or more. When a low molecular weight compound and a leveling agent are used in combination, sensitivity deterioration often occurs. For this reason, the amount of these used is generally 0.1 to 20 phr, preferably 0.1 to 10 phr, and the amount of the leveling agent used is suitably about 0.001 to 0.1 phr.

[Charge transport layer]
The charge transport layer refers to a part of the laminated photosensitive layer that functions to inject and transport charges generated in the charge generation layer and to neutralize the surface charge of the photoreceptor provided by charging. The main component of the charge transport layer can be said to be a charge transport component and a binder component that binds the charge transport component.

Examples of materials that can be used for the charge transport material include low molecular weight electron transport materials, hole transport materials, and polymer charge transport materials.
Examples of the electron transporting material include electron accepting materials such as asymmetric diphenoquinone derivatives, fluorene derivatives, and naphthalimide derivatives.
These electron transport materials may be used alone or as a mixture of two or more.
As the hole transport material, an electron donating material is preferably used.
Examples thereof include oxazole derivatives, oxadiazole derivatives, imidazole derivatives, triphenylamine derivatives, butadiene derivatives, 9- (p-diethylaminostyrylanthracene), 1,1-bis- (4-dibenzylaminophenyl) propane, Examples include styryl anthracene, styryl pyrazoline, phenylhydrazones, α-phenyl stilbene derivatives, thiazole derivatives, triazole derivatives, phenazine derivatives, acridine derivatives, benzofuran derivatives, benzimidazole derivatives, and thiophene derivatives.
These hole transport materials may be used alone or as a mixture of two or more.

  Moreover, the polymeric charge transport material represented below can be used. For example, a polymer having a carbazole ring such as poly-N-vinylcarbazole, a polymer having a hydrazone structure exemplified in JP-A-57-78402, and the like exemplified in JP-A-63-285552 The polysilylene polymer to be used, and aromatic polycarbonates exemplified by general formula (1) to general formula (6) of JP-A No. 2001-330973. These polymer charge transport materials can be used alone or as a mixture of two or more. In particular, the exemplified compounds disclosed in JP-A-2001-330973 are useful because of their good electrostatic characteristics.

  When polymerized cross-linked resin surface layers are laminated, polymer charge transport materials are less likely to ooze out the components constituting the charge transport layer into the cross-linked resin surface layer compared to low molecular charge transport materials, and the cross-linked resin surface layer is cured. It is a material suitable for preventing defects. In addition, since the charge transport material has high heat resistance due to the high molecular weight, there is little deterioration due to the heat of curing when forming the cross-linked resin surface layer.

  Examples of the polymer compound that can be used as the binder component of the charge transport layer include polystyrene, polyester, polyvinyl, polyarylate, polycarbonate, acrylic resin, silicone resin, fluorine resin, epoxy resin, melamine resin, urethane resin, and phenol resin. And thermoplastic or thermosetting resins such as alkyd resins. Of these, polystyrene, polyester, polyarylate, and polycarbonate are useful because many of them have good charge transfer characteristics when used as a binder component of a charge transport component. In addition, since the charge transport layer has a cross-linked resin surface layer laminated thereon, the charge transport layer is not required to have mechanical strength as compared with the conventional charge transport layer. For this reason, a material such as polystyrene, which is highly transparent but has a low mechanical strength and is difficult to apply in the prior art, can be effectively used as the binder component of the charge transport layer.

  These polymer compounds can be used singly or as a mixture of two or more kinds, or as a copolymer composed of two or more of these raw material monomers, and further copolymerized with a charge transport material.

  When an electrically inactive polymer compound is used for modifying the charge transport layer, a cardo polymer type polyester having a bulky skeleton such as fluorene, a polyester such as polyethylene terephthalate or polyethylene naphthalate, or a C type polycarbonate is used. Polycarbonate in which the 3,3 ′ portion of the phenol component is alkyl-substituted with respect to a bisphenol-type polycarbonate, polycarbonate in which the geminal methyl group of bisphenol A is substituted with a long-chain alkyl group having 2 or more carbon atoms, biphenyl or biphenyl Polycarbonate having an ether skeleton, polycarbonate having a long chain alkyl skeleton such as polycaprolactone and polycaprolactone (for example, described in JP-A-7-292095), acrylic resin, polystyrene, hydrogenated Diene is valid.

Here, the electrically inactive polymer compound refers to a polymer compound that does not include a chemical structure exhibiting photoconductivity such as a triarylamine structure.
When these resins are used in combination with a binder resin as an additive, the addition amount is preferably 50 wt% or less with respect to the total solid content of the charge transport layer due to restrictions on light attenuation sensitivity.

When a low molecular charge transport material is used, the amount used is 40 to 200 phr, preferably about 70 to 100 phr. When a polymer charge transport material is used, a material in which the resin component is copolymerized in an amount of about 0 to 200 parts by weight, preferably about 80 to 150 parts by weight with respect to 100 parts by weight of the charge transport component is preferably used.
When two or more kinds of charge transport materials are contained in the charge transport layer, it is preferable that the difference in ionization potential is small. Specifically, by setting the difference in ionization potential to 0.10 eV or less, Can be prevented from becoming a charge trap of the other charge transport material.
Regarding the relationship between the ionization potentials, the difference between the charge transporting material contained in the charge transporting layer and the curable charge transporting material described later is preferably 0.10 eV.

  In addition, the ionization potential value of the charge transport material in the present invention is a numerical value obtained by measuring by a general method using the atmospheric atmospheric ultraviolet photoelectron analyzer AC-1 manufactured by Riken Keiki Co., Ltd.

  In order to satisfy high sensitivity, the charge transport component is preferably added in an amount of 70 phr or more. In addition, α-phenylstilbene compounds, benzidine compounds, butadiene compound monomers, dimers, and polymer charge transport materials having these structures in the main chain or side chain are materials having high charge mobility. Many are useful.

  Examples of the dispersion solvent that can be used in preparing the charge transport layer coating material include ketones such as methyl ethyl ketone, acetone, methyl isobutyl ketone, and cyclohexanone, ethers such as dioxane, tetrahydrofuran, and ethyl cellosolve, and aromatics such as toluene and xylene. , Halogens such as chlorobenzene and dichloromethane, and esters such as ethyl acetate and butyl acetate. Of these, methyl ethyl ketone, tetrahydrofuran, and cyclohexanone are preferable because they have a lower environmental impact than chlorobenzene, dichloromethane, toluene, and xylene. These solvents can be used alone or in combination.

  The charge transport layer can be formed by dissolving or dispersing a mixture or copolymer containing a charge transport component and a binder component as main components in an appropriate solvent, and applying and drying the mixture. As the coating method, a dipping method, a spray coating method, a ring coating method, a roll coater method, a gravure coating method, a nozzle coating method, a screen printing method, or the like is employed.

Since the cross-linked resin surface layer is laminated on the upper layer of the charge transport layer, the thickness of the charge transport layer in this configuration does not need to be designed to increase the thickness of the charge transport layer in consideration of film scraping in actual use. It is.
The film thickness of the charge transport layer is practically about 10 to 40 μm, more preferably about 15 to 30 μm for the purpose of ensuring the required sensitivity and charging ability.

  If necessary, low-molecular compounds such as antioxidants, plasticizers, lubricants and ultraviolet absorbers and leveling agents described later can be added to the charge transport layer. These compounds can be used alone or as a mixture of two or more. When a low molecular weight compound and a leveling agent are used in combination, sensitivity deterioration often occurs. For this reason, the amount of these used is generally 0.1 to 20 phr, preferably 0.1 to 10 phr, and the amount of the leveling agent used is suitably about 0.001 to 0.1 phr.

[Crosslinked surface layer]
The cross-linked resin surface layer refers to a protective layer formed on the surface of the photoreceptor. This protective layer is formed by coating a coating material and then forming a resin having a crosslinked structure by a polycondensation reaction. Since the resin film has a crosslinked structure, it has the strongest wear resistance among the layers of the photoreceptor. In addition, since a crosslinkable charge transport material is blended, the charge transport property is similar to that of the charge transport layer.

  As the charge transport material to be contained in the surface layer, a known charge transport compound can be used. Examples of the polymerizable or crosslinkable monomer or oligomer include a chain polymerization compound having an acryloyloxy group and a styrene group, and a sequential polymerization compound having a hydroxyl group, an alkoxysilyl group, and an isocyanate group. From the viewpoint of the obtained electrophotographic characteristics, versatility, material design, and production stability, a combination of a hole transporting compound and a chain polymerization material is preferable. Furthermore, both a hole transporting group and an acryloyloxy group are included in the molecule. Particularly preferred is a system in which a compound having a crosslinking is crosslinked. It can be crosslinked and cured using heat, light and radiation. The crosslinkable resin is preferably three-dimensionally crosslinked.

[Material structure of cross-linked surface layer]
In the present invention, the charge transport layer itself can be composed of a crosslinked or cured resin. As a composition of a material that can be polymerized or cross-linked, a compound having a charge transport structure and having at least one (meth) acryloyloxy group can be used. Alternatively, the composition may be combined with a monomer or oligomer having one or more (meth) acryloyloxy groups not including a charge transport structure. Such a compound can be contained in at least the coating liquid to form a surface layer, and can be crosslinked and cured by applying energy by heat, light, or radiation such as electron beam or γ-ray. For example, the charge transporting compound in the following general formula (1) can be mentioned.

(In the formula, d, e and f are each an integer of 0 or 1, 13 represents a hydrogen atom or a methyl group, R14 and R15 represent substituents other than a hydrogen atom, and a plurality of cases may be different. H represents an integer of 0 to 3. Z represents a single bond, a methylene group, an ethylene group, [Chemical Formula 2] to [Chemical Formula 4].)
As the substituents R14 and R15 other than a hydrogen atom, an alkyl group having 1 to 6 carbon atoms is particularly preferable from the viewpoints of electrical characteristics, coating film formability, and mechanical strength.

[Exemplary compounds]
The exemplary compounds are listed below.

2- [4 '-(Di-p-tolyl-amino) -biphenyl-4-yl] -ethyl acrylate

Acrylic acid 2- [4 '-(di-p-tolyl-amino) -biphenyl-4-yl]

  Among charge transporting compounds having radical polymerizability, a compound having a triphenylamine skeleton as represented by the general formula (1) is advantageous for increasing the sensitivity of an electrophotographic photoreceptor. Further, among many compounds, the structure of the general formula (1) has excellent curability inside the film and is extremely advantageous.

  In the case of the charge transport layer, the thickness of the crosslinked resin layer is preferably 5 μm or more and 50 μm or less, and more preferably 10 μm or more and 35 μm or less. In the case of the second charge transport layer or protective layer, the thickness is preferably 0.1 μm or more and 20 μm or less, and more preferably 1 μm or more and 10 μm or less.

[Method for creating surface layer]
The dispersion solvent used when preparing the cross-linked resin surface layer coating is preferably one that sufficiently dissolves the monomer. In addition to the ethers, aromatics, halogens, esters described above, cellosolves such as ethoxyethanol, Mention may be made of propylene glycols such as 1-methoxy-2-propanol. Among these, methyl ethyl ketone, tetrahydrofuran, cyclohexanone, and 1-methoxy-2-propanol are preferable because they have a lower environmental impact than chlorobenzene, dichloromethane, toluene, and xylene. These solvents can be used alone or in combination.

  Examples of the coating of the cross-linked resin surface layer coating include dipping, spray coating, ring coating, roll coater, gravure coating, nozzle coating, and screen printing. In many cases, since the pot life of the paint is not long, a means capable of coating the required amount with a small amount of paint is advantageous in terms of environmental consideration and cost. Of these, the spray coating method and the ring coating method are preferred.

[Crosslinking method]
When the crosslinked resin surface layer is formed, a UV irradiation light source such as a high-pressure mercury lamp or a metal halide lamp mainly having an emission wavelength in ultraviolet light can be used. In addition, a visible light source can be selected in accordance with the absorption wavelength of the radical polymerizable substance or the photopolymerization initiator. Irradiation light amount is 50 mW / cm ² or more, preferably 1000 mW / cm ² or less, it takes time for the curing reaction is less than 50 mW / cm ^2. If it is higher than 1000 mW / cm ^2, the progress of the reaction becomes non-uniform, and local flaws are generated on the surface of the cross-linked charge transport layer, or many unreacted residues and reaction termination ends are generated. In addition, internal stress increases due to rapid crosslinking, which causes cracks and film peeling.

  If necessary, low molecular compounds and leveling agents such as antioxidants, plasticizers, lubricants, UV absorbers and the like described in the charge generation layer and polymer compounds described in the charge transport layer may be added to the cross-linked resin surface layer. You can also. These compounds can be used alone or as a mixture of two or more. When a low molecular weight compound and a leveling agent are used in combination, sensitivity deterioration often occurs. For this reason, the amount used is generally 0.1 to 20 wt%, preferably 0.1 to 10 wt%, and the leveling agent used is about 0.1 to 5 wt% in the total solid content of the paint.

[Composition of convex part]
In addition, the surface of the photoreceptor in the present invention has a configuration in which a number of convex portions containing a cross-linked product of a charge transporting compound are provided on the surface of the cross-linked surface layer.
Conventionally, there has been used a method for defining and grasping a phenomenon related to the blade cleaning property of a photoconductor by a property parameter such as Rz or Ra representing the surface roughness of the photoconductor. Surface textures that cannot be grasped are used as a means for solving problems. That is, the present invention has been made by clarifying that the specific convex portion (selective combination of a specific material and a specific shape) formed on the surface has a function specific to cleaning properties. It can also be said that the unexpected effect by the convex part itself was found.

That is, the present invention is based on the knowledge that the above-mentioned convex portions formed on the surface, that is, the “specific convex portions themselves” have a function specific to cleaning properties when viewed from such a viewpoint. In other words. First, the specific shape will be described. RzJIS defined in the 2001 JIS standard (JIS B0601: '01) quantifies and grasps the peaks and valleys on the surface as the distance from the average line. Is to grasp the convex portion as a distance from the waviness curve to the top of the “crosslinked surface layer on which the convex portion is formed”.
Incidentally, RzJIS is expressed by the following calculation formula (1), and a reference length roughness curve obtained by applying a phase compensation bandpass filter with cutoff values λc and λs to a measurement sectional curve obtained from a surface roughness meter. Is the sum of the average of the highest mountain height from the highest peak to the fifth highest and the average of the highest valley depth from the deepest bottom to the fifth highest.

RzJIS = 1 / 5Σ (Zpi + Zvj); i, j = 1 to 5 Formula (1)
(Zpi: distance from the average line of the i-th mountain, Zvj: distance from the average line of the j-th valley)

  As mentioned above, the five peaks and the five valleys are simply selected in order from the largest in the specified measurement length, and the deepest valley is not always next to the highest mountain. May be selected separately at separate locations. Even with the same Rz value, the surface shape may be different. In addition, since there are peaks and valleys that were not selected, it is insufficient to fully grasp the surface properties.

  An example of the concept of the independent convex portion of the present invention is shown in FIG. 3 (perspective view). This convex portion protrudes outward from the surface of the photoreceptor. A convex part can be defined as a convex part having a height of 1/2 or more of Rz in a specified measurement length. This specific convex portion, together with the specific material, is important for cleaning performance. Next, it is preferable that the convex portions are independent. Furthermore, it is preferable that the top of the convex portion is flat. Further, it is preferably polished or smooth. Moreover, it is preferable that the skirt part of a convex part is smooth. The skirt may be a groove that surrounds the protrusion and separates the other protrusion.

FIG. 4 shows a randomly arranged convex portion as a conceptual example of the shape and arrangement of the convex portion of the present invention.
FIG. 4 shows the shape of a cross section (plan view) at a height of one half of Rz of the convex portion. The cross-sectional shape may be any shape as long as it has the above-described configuration, and is not limited to the illustrated shape. The arrangement of the convex portions may be random or regular. The shaded portion is a convex portion, and the convex portion indicates that the region is outside the surface of the photoreceptor from a region other than the shaded portion.

  The measuring direction can be arbitrarily determined as long as it is an image forming surface of the photoreceptor. The measurement direction in the case of the cylindrical photosensitive member may be any of the circumferential direction, the axial direction, and the direction between them, but is set to the axial direction for convenience from the form of the measuring table of the roughness measuring machine.

[Height of convex part]
The height of the convex part is a distance to the top of the convex part based on the waviness curve obtained from the roughness measurement of the crosslinked surface layer on which the convex part is formed. Speaking of the measurement cross section curve obtained from the roughness meter, depending on the position and direction of the measurement length, it may pass through the skirt without passing through the top of the convex part, but if a peak is recognized in the measurement cross section curve, Considering that there is a high probability that there is a peak in the vicinity, the number of peaks in the measurement cross-section curve was substituted for the number of protrusions on the actual photoreceptor surface. In addition, by counting the protrusions greater than or equal to Rz, an attempt was made to increase the probability of grasping the actual protrusions by counting the protrusions greater than or equal to 1/2 × Rz.

  As described above, in the present invention, since the cross-linked surface layer includes waviness, it is appropriate to include waviness displacement in the convex height. That is, in the measurement cross-section curve, one deepest valley in the measurement length of 12 mm is selected, and the distance to the peak of each peak in the measurement length is uniformly measured with reference to this, and the convex height is measured. Asked.

[Number of convex parts]
In the present invention, the density (also referred to as “surface density” of the convex portions) can be defined by measuring the number of convex portions within a specified area at an arbitrary position on the surface of the photoreceptor. An area for measurement in an appropriate range is designated by the shape and size of the convex portion. Usually, the area is 100 μm square to 15 mm square. For example, in the case of the spray coating method, about 1 mm to 15 mm square is selected. However, the method for defining the surface density of the protrusions is limited to a measuring machine, and dedicated measurement software is often required, so that it may not be possible to measure easily. The present invention employs a method in which a simple measurement using an easy-to-use surface roughness meter is performed at least four times, and an average value of the number of convex portions having a height of 1/2 × RzJIS or more is obtained and defined. To ensure measurement reliability. Therefore, it was specified by specifying a measurement length of 12 mm at an arbitrary position on the surface and measuring the number of convex portions on the surface.

  The case where the number of protrusions is measured will be specifically described. First, RzJIS conforming to JIS B0601: '01 is obtained. In the present invention, an example using a shape measuring machine (Surfcom 1400D (measuring element DT43801) manufactured by Tokyo Seimitsu Co., Ltd.) capable of measuring surface roughness is shown, but the present invention is not limited to this. The density of the convex portions of the present invention is measured by counting the number of convex portions having a height of ½ × RzJIS or more in the height. A program to automatically measure the height was created, and by measuring digital data including a waviness curve, the convexity of 1/2 × RzJIS or higher was measured from the waviness curve.This digital data measured about 30,000 measurements. The number of points is included, but this is reduced to about 1/5 and thinned to 7680. The data obtained by this sampling is arranged in order of measurement points from the start of measurement, and the change in height is obtained. It was decided to recognize the peak corresponding to the convexity when a measurement point with a change in the number of points was found. Use of a convex having a height of ½ × RzJIS or higher is particularly effective for evaluating the slipping of toner.

  The measurement length is usually about 100 μm to 15 mm, although it depends on the surface forming method, the particle size of the toner used or the properties of the blade. About the convex part of the surface layer by spray coating, 1 mm to 15 mm can be selected. When the convex portions are formed on the surface of the photoreceptor by spray coating, it is preferable that the convex portions are 30 or more and 300 or less per 12 mm measurement length. Even when the lubricant is supplied and used, it is advantageous from the viewpoint of applicability.

Spray coating was performed under different conditions on a cylindrical laminated photoreceptor having a surface comprising a charge transport layer, and six types of surfaces with different convex portions were obtained. The conditions were as follows: spraying speed 10 (mm / s), photoreceptor speed 200 (rpm), spray gun opening 8 (scale number), and atomization pressure 2 (kgf / mm ² ). When four points were measured as measurement data at arbitrary positions in the axial direction of the surface of the photoreceptor, all of them were similar measurement cross-section curves. Moreover, the value of Rz had a small specific fluctuation. These results are shown in the examples.
The measurement results are shown in Table 1 below.
Table 2 below shows the number of protrusions having a height of ½ × Rz or more. Here, in conditions 1 to 6, the spraying speed (mm / s) is 5, 5, 10, 10, 15, 15 respectively, and the photosensitive member rotation speed (rpm) is 100, 300, 200, 300, 200, respectively. 100, spray gun opening (scale) is 8, 4, 4, 8, 8, 12, respectively, and atomization pressure (kgf / mm ² ) is ² , 1, 2, 3, 1, ² , respectively. It is.
n = 1 to 4 are data values at four different points under the same conditions.

  It is considered that the average value of the number of convex portions obtained from the measurement cross-sectional curve is representative of the number of randomly arranged convex portions on the actual surface.

  The convex portion in the present invention can be grasped by the fact that the height of the convex portion is larger than one half of Rz when the sectional curve is obtained with a surface roughness meter. As described above, any technique including a known technique may be used as a method for realizing a specific independent convex portion on the photoconductor of the present invention. The method for forming the convex portion is a method of forming the convex portion forming coating liquid by atomizing and transferring it from the outside, or forming the surface with mechanical or thermal energy applied to the surface once formed. There is a way. Examples of the former include a spray coating method, an inkjet method, and a printing method. In the latter, there are a mold processing method using a female mold, and a groove portion around a convex portion by laser ablation using a mask. As a result, it is sufficient that a convex portion is formed. Both can be used in the present invention. The former is preferably less distorted. Since the latter is accompanied by destruction of the surface layer, it is positioned as a method next to the former. Further, when processing strain is involved, thermal annealing may be added later.

  In particular, a plurality of independent convex portions by the spray coating method were confirmed by a laser microscope image, and the shape of the convex portion like a “bell” was confirmed at an aspect ratio of 50: 1. It was the shape of rotating a parabola. The shape is expected to be unique to the method of forming the protrusions. FIG. 5 shows a conceptual diagram when the vertical and horizontal magnifications are close to each other. Expected to be close to the cross-sectional shape of the bell extended in the horizontal direction.

  The configuration in which the above-described independent convex portions of the present invention are provided on the surface is not provided with many fine concave portions on the surface of the photoreceptor as disclosed in Japanese Patent Application Laid-Open No. 2007-233359. It is not a well-type unevenness as disclosed in 2007-233359.

  As an effect of the present invention, the cleaning blade made of an elastic body is brought into contact with the tops of a large number of convex portions, so that the blade slides better because it is held at a large number of contact points. Since the groove portions are connected, foreign matter is often easily discharged. Further, by repeating the image forming process, even if the convex portion is destroyed, the destruction is often limited to the convex portion, which is convenient. The protrusion of the present invention can solve the problem more excellently than the conventional structure in which a large number of recesses are provided.

The height of the convex portion on the surface of the photosensitive member is set in an appropriate range using a specific material as described in detail later.
As for the height of a convex part, 6 micrometers or less are preferable. If it is larger than this, the toner may slip through. The height can be determined according to the volume average particle diameter of the toner. It is preferable to make the volume average particle diameter of the toner or less. Moreover, it is more preferable that it is 0.5 micrometer or more.

[Material of convex part]
The convex member quality will be described. By using a material in the same category as that of the surface layer, high compatibility can be obtained, and there is no peeling of the convex portion, and a high-strength one can be obtained. During manufacturing, there is an advantage that the state of the convex portions (the size and number of convex portions) can be adjusted in correlation with the surface state (contour) of the surface layer. In the present invention, the convex portion contains a cross-linked product of a specific charge transporting compound as a curable resin and has a content in a specific range. Therefore, since the strength of the convex portion itself is large, it has resistance against the cleaning blade. As the curable resin, it is preferable that the crosslink density is high enough that the convex portions are not dissolved in a solvent such as tetrahydrofuran or toluene. That is, it is necessary to form a convex portion that can withstand the frictional force of the cleaning blade. The cleaning blade is generally made of a hard rubber-like elastic body such as polyurethane and has a plate shape. For example, a case where this is brought into contact with the surface of the photoreceptor in the counter direction will be described.
The transfer residual toner is cleaned by sliding on the surface of the photoconductor. At this time, the tip of the cleaning blade is subjected to minute vibrations due to friction with the surface of the photoconductor (the blade itself is not attached to the stick by the frictional force between the blade and the photoconductor). It is said that a stick slip that periodically repeats a slip) occurs, and the vibration state changes depending on the characteristics of the cleaning blade and the condition of the surface of the photoreceptor. It is considered preferable for cleaning that the fine vibrations continue stably. In the present invention, it is considered that it also has the effect of promoting fine vibrations. The tip of the cleaning blade is configured to be continuously stabilized.

  The shape of the convex portion on the surface of the photoreceptor of the present invention can be measured using a known laser microscope, optical microscope, electron microscope, or atomic force microscope. For example, an ultra-deep shape measurement microscope VK-8550 manufactured by Keyence Corporation, a surface shape measurement system Surface Explorer SX-520DR model manufactured by Ryoka System Co., Ltd., a scanning confocal laser microscope OLS3000 manufactured by Olympus, etc. are used as laser microscopes. it can. As an optical microscope, a digital microscope VHX-500 manufactured by Keyence Corporation and a 3D digital microscope VC-7700 manufactured by OMRON Corporation can be used. As the electron microscope, a 3D real surface view microscope VE-9800 manufactured by Keyence Corporation and a scanning electron microscope SUPERSCAN SS-550 manufactured by Shimadzu Corporation can be used. As an atomic force microscope, a nanoscale hybrid microscope VN-8000 manufactured by Keyence Corporation and a scanning probe microscope SPM-9600 manufactured by Shimadzu Corporation can be used. Using these microscopes, it is possible to observe and measure the shape of the projection, the state of the skirt, the arrangement, the height, or the top.

[Method of forming convex portions on the surface of the photoreceptor]
The method for forming the convex portion is not particularly limited as long as it can satisfy the requirements for the convex portion described above, and various methods as described above can be adopted, but the convex shape of the material and shape is formed. A spray coating method is preferred in which a projection liquid is sprayed from the spray gun onto the surface of the electrophotographic photosensitive member to form convex portions.

The spray coating method will be described below.
A known spray processing (coating) method can be used. FIG. 6 shows an outline of the spray coating apparatus.
The photosensitive drum is rotated at a predetermined speed by a rotation driving device (not shown). Next, while supplying the coating liquid and gas to the moving application body having a spray gun at a predetermined pressure, the coating liquid and the gas are oscillated (moved) in the axial direction of the photosensitive drum, and the sprayed coating liquid is sprayed on the photosensitive drum. A coating film can be formed.

In the present invention, the basic coating conditions that affect the shape of the protrusions (the size of the protrusions and the number of protrusions) are mainly the concentration of the coating liquid and the type of solvent (whether the solubility is high, toxicity, risk, etc.) In addition, the resulting viscosity and evaporation rate can be mentioned. In addition, the rotational speed of the photoconductor, the oscillating speed, the form of the spray gun outlet, and the pressure and flow rate of the gas to be supplied are This is a major condition because it is a condition that is easy to control reliably.
Further, the viscosity of the coating liquid varies depending on the coating material used, and therefore, it does not mean that the convexity carrying by coating is not affected. However, in the present invention, the “structure part (A) and the structure part (B)” When the surface roughness of the surface layer after forming the protrusions is less than 90 wt% with respect to the total weight and expressed in RzJIS, the number of protrusions having a height of 1/2 × RzJIS or more is the measured length. “30 to 300 per 12 mm” means, for example, that the total amount of the compound having the charge transporting structure and the amount of polyfunctional monomer having no charge transporting structure in the coating liquid is 10% to 20% (weight) Part / coating liquid part by weight).

[Concentration of donor in the convex part]
In addition, as described above, the concentration of the crosslinked body containing the structural unit (A) having a convex charge transporting structure needs to be higher than that of the surface layer. This is to reduce the difference in charge transport capability between the convex portion and the surface layer and make the image density more uniform. However, even if the content concentration is too high, the ratio of the monomer for the structural part (B) not having the charge transporting structure is too low and the strength of the convex part itself is lost, which is inconvenient. . Therefore, the monomer-containing concentration for the structural unit (A) having the charge transporting structure in the convex portion (with respect to the total amount of the radical polymerizable monomer having no charge transporting structure and the monomer having the charge transporting structure) is 90 wt. Must be less than%.

[Combination of recess formation and protrusion formation method]
Further, as another method for forming the convex portion, a method of forming the concave portion in the surface layer in advance is also useful. The merit of forming the recess is as follows: 1. Relieve the difference in charge transport capability between the convex part and the surface layer; 2. It is easy to control the number of projections when the projections are formed by spraying; The convex part is hard to be destroyed. Regarding 1, when the convex portion is formed in the concave portion, the ratio of the convex portion portion having a high content concentration of the crosslinked body including the structural unit having the charge transporting structure is increased by the depth of the concave portion. There is an effect of promoting the effect of the content concentration in the convex portion. As for No. 2, when the convex portions are formed by spraying, the number of convex portions formed after coating can be changed according to the number of concave portions of the surface layer. As for No. 3, when the convex part is formed on the concave part, the ground surface and the adhesion area are increased and the toughness against the friction of the blade or the like is larger than the convex part formed on the smooth surface. Increase.

[Method of forming recesses]
The method for forming the recess is not particularly limited, and a method of adding an appropriate amount of reactive silicone oil into the surface layer, sandblasting, laser processing, or a method using a mold having a specific shape is conceivable.
The reactive silicone oil is a reactive silicone compound characterized by having a methacryloyloxy group as a radical polymerizable functional group and having a dimethylsiloxane structure as a repeating unit.
As specific examples, those having one and two radical polymerizable functional groups are shown in the general formulas (4) and (5), respectively.

（上記一般式（４）中のＲ４１ はメタクリロイルオキシ基、Ｒ４２ 、Ｒ４３ 、Ｒ４４、Ｒ４５、Ｒ４６ は互いに同一又は異種の水素原子または炭素数１〜１２のアルキル基又はアリール基、Ａは炭素数２〜６のアルキレン基または単結合、ｎは２以上の整数である。）

(In the general formula (4), R41 is a methacryloyloxy group, R42, R43, R44, R45, R46 are the same or different hydrogen atoms or alkyl groups or aryl groups having 1 to 12 carbon atoms, and A is 2 carbon atoms. -6 alkylene group or single bond, n is an integer of 2 or more.)

（上記一般式（５）中のＲ４１ 、Ｒ４６ は、メタクリロイルオキシ基、Ｒ４２ 、Ｒ４３ 、Ｒ４４、Ｒ４５ は互いに同一又は異種の水素原子または炭素数１〜１２のアルキル基又はアリール基、Ａは炭素数２〜６のアルキレン基または単結合、ｎは２以上の整数である。）

(In the above general formula (5), R41 and R46 are methacryloyloxy groups, R42, R43, R44 and R45 are the same or different hydrogen atoms or alkyl groups or aryl groups having 1 to 12 carbon atoms, and A is the number of carbon atoms. 2 to 6 alkylene groups or single bonds, n is an integer of 2 or more.)

A reactive silicone oil characterized by having a radically polymerizable functional group and having a dimethylsiloxane structure as a repeating unit is an ester of methacrylic acid and alkylene glycol, which is a known method. A method of condensing a siloxane compound, an ester of methacrylic acid and allyl alcohol, and the like can be prepared by a method of adding a trimethylsilyl compound or a polydimethylsiloxane compound thereto, but commercially available products can also be used.
Examples of commercially available products include X-22-164A (functional group equivalent 860, manufactured by Shin-Etsu Chemical Co., Ltd.), X-22-164B (functional group equivalent 1630, manufactured by Shin-Etsu Chemical Co., Ltd.), X-22-164C. (Molecular weight 2370, manufactured by Shin-Etsu Chemical Co., Ltd.), X-22-164E (functional group equivalent 3900, manufactured by Shin-Etsu Chemical Co., Ltd.), X-22-174DX (functional group equivalent 4600, manufactured by Shin-Etsu Chemical Co., Ltd.), X-22-2426 (functional group equivalent 12000, manufactured by Shin-Etsu Chemical Co., Ltd.) and the like can be mentioned, but are not limited thereto. The functional group equivalent here means the ratio of molecular weight to the number of functional groups. These reactive silicone oils may be used alone or in combination of two or more.
When the functional group equivalent is lower than 500, the reactivity is high and the amount of the functional group equivalent incorporated into the film increases, and the concave portion on the surface is not formed. On the other hand, if it is higher than 12000, the reactivity is not sufficient, and the amount of silicone oil that does not react with the film increases and comes out on the surface in large quantities, so that the target film is not formed.
Regarding the addition amount, when the number of functional groups of the reactive silicone oil is 2 and the functional group equivalent is 500 to 4000, it is 1 to 25% with respect to the solid content of the coating liquid forming the cured surface layer. Is desirable.
Moreover, when the number of functional groups of the reactive silicone oil is 1 and the functional group equivalent is 4000 to 12000, it is desirable that the content is 1 to 10% with respect to the solid content of the coating liquid forming the cured surface layer.

[Configuration of image forming apparatus]
Hereinafter, an image forming apparatus used in the present invention will be described with reference to the drawings.
FIG. 7 is a schematic diagram for explaining the image forming apparatus of the present invention, and modifications as will be described later also belong to the category of the present invention.
In FIG. 7, a photoreceptor (11) is an electrophotographic photoreceptor on which a cross-linked resin surface layer is laminated. Although the photoconductor (11) has a drum shape, it may be a sheet or an endless belt.
As the charging means (12), known means such as a corotron, a scorotron, a solid state charger (solid state charger), and a charging roller are used. As the charging unit, one that is in contact with or close to the photosensitive member is preferably used from the viewpoint of reducing power consumption. In particular, in order to prevent contamination of the charging unit, a charging mechanism disposed in the vicinity of the photosensitive member having an appropriate gap between the surface of the photosensitive member and the charging unit is desirable. As the transfer means (16), the above charger can be generally used, but a combination of a transfer charger and a separation charger is effective.

  Light sources used for the exposure means (13), the charge removal means (1A), etc. include fluorescent lamps, tungsten lamps, halogen lamps, mercury lamps, sodium lamps, light emitting diodes (LEDs), semiconductor lasers (LDs), and electroluminescence (ELs). Examples of luminescent materials such as 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.

The toner (15) developed on the photosensitive member by the developing means (14) is transferred to a printing medium (18) such as printing paper or an OHP slide, but not all is transferred. The toner remaining in the toner is also generated. Such toner is removed from the photoreceptor by the cleaning means (17). As the cleaning means, a rubber cleaning blade, a brush such as a fur brush, a mag fur brush, or the like can be used.
When the electrophotographic 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. If this is developed with toner of negative (positive) polarity (detection fine particles), a positive image can be obtained, and if developed with toner of positive (negative) polarity, a negative image can be obtained. A known method is applied to the developing unit, and a known method is also used for the charge eliminating unit.

FIG. 8 shows another example of the electrophotographic process according to the present invention. In FIG. 8, a photoreceptor (11) is an electrophotographic photoreceptor in which a cross-linked resin surface layer is laminated. The photoconductor (11) has a belt-like shape, but may be in the form of a drum, a sheet, or an endless belt. The photosensitive member (11) is driven by the driving means (1C), charged by the charging means (12), image exposure by the exposure means (13), development (not shown), transfer by the transfer means (16), pre-cleaning exposure. Exposure before cleaning by the means, cleaning by the cleaning means (17), and static elimination by the static elimination means (1A) are repeated. In FIG. 8, light irradiation for pre-cleaning exposure is performed from the support side of the photoreceptor (in this case, the support is translucent).
The above electrophotographic process exemplifies an embodiment of the present invention, and other embodiments are of course possible. For example, the pre-cleaning exposure is performed from the support side, but this may be performed from the photosensitive layer side, or image exposure and irradiation with static elimination light may be performed from the support side. On the other hand, the light irradiation process is illustrated as image exposure, pre-cleaning exposure, and static elimination exposure. In addition, a pre-transfer exposure, a pre-exposure of image exposure, and other known light irradiation processes are provided to light the photosensitive member Irradiation can also be performed.

  Further, the image forming means as described above may be fixedly incorporated in a copying machine, a facsimile, or a printer, but may be incorporated in these apparatuses in the form of a process cartridge. There are many shapes of the process cartridge, and a general example is shown in FIG. Although the photoconductor (11) has a drum shape, it may be a sheet or an endless belt.

  FIG. 8 shows another example of the image forming apparatus according to the present invention. In this image forming apparatus, a charging unit (12), an exposure unit (13), black (Bk), cyan (C), magenta (M), and yellow (Y) are provided around the photoconductor (11). Developing means (14Bk, 14C, 14M, 14Y), an intermediate transfer belt (1F) as an intermediate transfer member, and a cleaning means (17) are arranged in this order. Here, the subscripts Bk, C, M, and Y shown in the figure correspond to the color of the toner, and are added or omitted as appropriate. The photoreceptor (11) is an electrophotographic photoreceptor on which a cross-linked resin surface layer is laminated. Each color developing means (14Bk, 14C, 14M, 14Y) can be controlled independently, and only the color developing means for image formation is driven. The toner image formed on the photoreceptor (11) is transferred onto the intermediate transfer belt (1F) by the first transfer means (1D) disposed inside the intermediate transfer belt (1F). The first transfer means (1D) is arranged so as to be able to come into contact with and separate from the photoreceptor (11), and the intermediate transfer belt (1F) is brought into contact with the photoreceptor (11) only during the transfer operation. Each color image is sequentially formed, and the toner images superimposed on the intermediate transfer belt (1F) are collectively transferred to the printing medium (18) by the second transfer means (1E) and then fixed by the fixing means (19). The image is formed by fixing. The second transfer means (1E) is also arranged so as to be able to contact and separate from the intermediate transfer belt (1F), and abuts on the intermediate transfer belt (1F) only during the transfer operation.

  In the transfer drum type image forming apparatus, since the toner images of the respective colors are sequentially transferred onto the transfer material electrostatically attracted to the transfer drum, there is a restriction on the transfer material that cannot be printed on cardboard, as shown in FIG. Such an intermediate transfer type image forming apparatus is characterized in that the toner images of the respective colors are superimposed on the intermediate transfer body (1F), and therefore, there is no restriction on the transfer material. Such an intermediate transfer system is not limited to the apparatus shown in FIG. 10, but can be applied to the image forming apparatus shown in FIGS. 7, 8, 9 and FIG. 11 (a specific example is shown in FIG. 12) described later. it can.

  FIG. 11 shows another example of the image forming apparatus according to the present invention. This image forming apparatus is a type using four colors of yellow (Y), magenta (M), cyan (C), and black (Bk) as toners, and an image forming unit is provided for each color. In addition, photoconductors (11Y, 11M, 11C, and 11Bk) for each color are provided. The photoreceptor (11) used in this image forming apparatus is an electrophotographic photoreceptor on which a cross-linked resin surface layer is laminated. Around each photoconductor (11Y, 11M, 11C, 11Bk), a charging means (12), an exposure means (13), a developing means (14), a cleaning means (17), and the like are disposed. Further, a transfer transfer belt (1G) as a transfer material carrier that comes in contact with and separates from each transfer position of each photoconductor (11Y, 11M, 11C, 11Bk) arranged on a straight line is hung by a driving means (1C). Has been passed. A transfer means (16) is disposed at a transfer position facing each of the photoconductors (1Y, 1M, 1C, 1Bk) with the conveyance transfer belt (1G) interposed therebetween.

  A tandem type image forming apparatus as shown in FIG. 11 has a photoconductor (1Y, 1M, 1C, 1Bk) for each color, and print media (1G, each color toner image) held on a transfer transfer belt (1G). Since the transfer is sequentially performed in step 18), it is possible to output a full-color image much faster than a full-color image forming apparatus having only one photoconductor.

[Supply zinc stearate]
In the present invention, as shown in FIG. 13, as the zinc stearate supply means for supplying the lubricant (3A) to the surface of the photoreceptor, a lubricant application device (3C) may be provided for the above-described image forming apparatus.
This lubricant application device has a fur brush (3B) as an application member, a solid lubricant (3A), and a pressure spring (3D) for pressing the lubricant in the direction of the fur brush. The solid lubricant (3A) at this time is zinc stearate molded into a bar shape. The fur brush (3B) has a brush tip in contact with the surface of the photoconductor, and by rotating about the shaft, the solid lubricant (3A) is pumped up to one end of the brush to reach the contact position with the surface of the photoconductor. It is carried and conveyed to the surface of the photoreceptor.
Further, even if the solid lubricant (3A) is scraped off by the fur brush (41) over time, the solid lubricant (3A) is solid at a predetermined pressure by the pressurizing spring (3D) so that it does not come into contact with the fur brush (3B). The lubricant (3A) is pressed toward the fur brush (3B). As a result, even a small amount of the solid lubricant 3A is always pumped uniformly to the fur brush 3B.
Further, a solid lubricant fixing means for improving the fixability of the solid lubricant adhered to the surface of the photoreceptor may be provided. This means includes means for providing a plate such as a cleaning blade by a trailing method, and means for pressing a rubber roll against the photosensitive member.
Examples of the solid lubricant (3A) include lead oleate, zinc oleate, copper oleate, zinc stearate, cobalt stearate, iron stearate, copper stearate, zinc palmitate, copper palmitate, zinc linolenate. Fatty acid metal salts such as polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polytrifluorochloroethylene, dichlorodifluoroethylene, tetrafluoroethylene-ethylene copolymer, tetrafluoroethylene-oxafluoropropylene copolymer Fluorine-based resins such as coalesced are mentioned, but a metal stearate having a large effect of reducing the friction coefficient of the photoreceptor (1), particularly zinc stearate is more preferable.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to a following example. Note that “parts” used in the examples all represent parts by weight.

[Underlayer]
An undercoat layer was formed on an Al support (outer diameter: 40 mmφ) by an immersion method so that the film thickness after drying was 3.5 μm.
(Coating liquid for undercoat layer)
Alkyd resin 6 parts (Beckosol 1307-60-EL, manufactured by Dainippon Ink & Chemicals, Inc.)
Melamine resin 4 parts (Super Becamine G-821-60, manufactured by Dainippon Ink & Chemicals, Inc.)
Titanium oxide 40 parts (CR-EL: Ishihara Sangyo)
50 parts of methyl ethyl ketone

[Charge generation layer]
On this undercoat layer, it was dip-coated in a charge generation layer coating solution containing a bisazo pigment having the following structure and dried by heating to form a charge generation layer having a thickness of 0.2 μm.
(Coating solution for charge generation layer)
2.5 parts of bisazo pigment with the following structure

Polyvinyl butyral (XYHL, manufactured by UCC) 0.5 part Cyclohexanone 200 parts Methyl ethyl ketone 80 parts

[Charge transport layer]
On this charge generation layer, a charge transport layer coating solution having the following structure was dip-coated and heat-dried to obtain a charge transport layer having a thickness of 22 μm.
(Coating liquid for charge transport layer)
Bisphenol Z-type polycarbonate 10 parts Low molecular charge transport material 10 parts

Tetrahydrofuran 80 parts 1% silicone oil in tetrahydrofuran 0.2 parts

[Crosslinked surface layer]
Using a crosslinked surface layer coating solution having the following constitution on the charge transport layer, drum rotation speed: 80 rpm, spray gun feed speed: 16.5 mm / s, discharge amount 4.5 ml / min, spraying pressure: 2.5 kgf / Cm ² , number of spraying; spray coating was performed under the conditions of one time, and touch-and-drying was performed for 10 minutes. Subsequently, UV curing was performed while rotating the drum at a distance of 120 mm from the drum and the UV curing lamp. The illuminance of the UV curing lamp at this position was 550 mW / cm ² (UV integrated light meter UIT-150, measured value by Ushio Inc.). The drum rotation speed was 25 rpm. When performing UV curing, UV curing was performed continuously for 3 minutes by circulating water at 30 ° C. in an aluminum drum. Then, it heat-dried at 130 degreeC for 30 minutes. As a result, a 5.0 μm-crosslinked resin surface layer was provided to obtain the electrophotographic photosensitive member of the present invention.
(Crosslinked surface layer coating solution)
Trifunctional or higher-functional radical polymerizable monomer having no charge transport structure 9 parts Trimethylolpropane triacrylate (KAYARAD TMPTA, manufactured by Nippon Kayaku)
Molecular weight: 382, number of functional groups: trifunctional, molecular weight / number of functional groups = 99
9 parts of radically polymerizable compound having a charge transporting structure (2- [4 ′-(di-p-tolyl-amino) -biphenyl-4-yl] -ethyl acrylate)

Photoinitiator 2 parts 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran 100 parts (KF50-100CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

[Convex]
Next, a trifunctional or higher functional radical polymerizable monomer having no charge transporting structure (abbreviated as “donor” in Table 1) is used for the crosslinked surface layer coating solution on the obtained electrophotographic photosensitive member. Two parts were spray-coated using a radical polymerizable compound having a charge transporting structure added to 10.8 parts.
The coating conditions are the same spray gun, drum rotation speed: 80 rpm, spray gun feed speed: 8.4 mm / s, discharge amount 1.6 ml / min, spray pressure: 3.0 kgf / cm ² , number of sprays The test was carried out once. Similarly, it was UV cured and heat dried. As a result, a convex portion containing a crosslinked resin was formed.

In Example 1, an electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the convex coating was changed to the following conditions.
Details of change: Coating conditions: drum rotation speed: 80 rpm, spray gun feed speed: 8.4 mm / s, discharge rate 1.0 ml / min, spraying pressure 3.0 kgf / mm ² , spraying frequency: changed once.

In Example 2, an electrophotographic photosensitive member was prepared in the same manner as in Example 2 except that the convex coating was changed to the following conditions.
Details of change: The amount of addition of the radical polymerizable compound having the charge transporting structure to 5.4 parts of the trifunctional or higher functional radical polymerizable monomer not having the charge transporting structure in the coating solution for the second convex portion Changed to 12.6 parts.

In Example 2, an electrophotographic photosensitive member was prepared in the same manner as in Example 2 except that the convex coating was changed to the following conditions.
Details of change: In the second convex coating solution, 3.6 parts of a tri- or higher functional radical polymerizable monomer having no charge transport structure is added to 3.6 parts of the radical polymerizable compound having a charge transport structure. Changed to 14.4 parts.

In Example 1, an electrophotographic photosensitive member was produced in the same manner as in Example 1 except that both the coating on the surface layer and the convex portion were changed to the following conditions.
Contents of change (1): In the first surface layer cross-linked surface layer coating solution, a reactive silicone oil having a radical polymerizable functional group (both ends-type methacryl-modified polysiloxane: X-22-164A, manufactured by Shin-Etsu Silicone Co., Ltd.) ) Is added.
Content of change (2): The coating condition of the second convex portion is the drum rotation speed: 80 rpm, spray gun feed speed: 8.4 mm / s, discharge amount 0.6 ml / min, spray pressure 2.5 kgf / mm ² , Number of sprays: Changed to 1

In Example 5, an electrophotographic photosensitive member was prepared in the same manner as in Example 5 except that the convex coating was changed to the following conditions.
Details of the change: Addition of a radical polymerizable compound having a charge transporting structure to 5.4 parts of a trifunctional or higher functional radical polymerizable monomer having no charge transporting structure in the coating solution for the second cross-linked protrusion Changed the amount to 12.6 parts.

In Example 5, it carried out similarly to Example 5 except changing the conditions of the coating of a convex part below.
Details of change: The amount of addition of the radical polymerizable compound having the charge transporting structure to 3.6 parts of the tri- or higher functional radical polymerizable monomer not having the charge transporting structure in the second crosslinking convex coating liquid Changed to 14.4 parts.

In Example 1, an electrophotographic photosensitive member was produced in the same manner as in Example 1 except that both the coating on the surface layer and the convex portion were changed to the following conditions.
Content of change (1): Reactive silicone oil having a radical polymerizable functional group (one-end type methacryl-modified polysiloxane: X-22-174DX, manufactured by Shin-Etsu Silicone Co., Ltd.) ) Is added.
Content of change (2): The coating condition of the second convex portion is the drum rotation speed: 80 rpm, spray gun feed speed: 8.4 mm / s, discharge amount 0.6 ml / min, spray pressure 2.5 kgf / mm ² , Number of sprays: Changed to 1

In Example 8, an electrophotographic photosensitive member was produced in the same manner as in Example 8 except that the convex coating was changed to the following conditions.
Details of change: The amount of addition of the radical polymerizable compound having the charge transporting structure to 5.4 parts of the trifunctional or higher functional radical polymerizable monomer having no charge transporting structure in the second cross-linking convex coating liquid Changed to 12.6 parts.

In Example 8, an electrophotographic photosensitive member was produced in the same manner as in Example 8 except that the convex coating was changed to the following conditions.
Details of change: The amount of addition of the radical polymerizable compound having the charge transporting structure to 3.6 parts of the tri- or higher functional radical polymerizable monomer not having the charge transporting structure in the second crosslinking convex coating liquid Changed to 14.4 parts.

  In Example 1, after formation of the first surface layer, blasting was performed using glass beads under the following conditions. That is, a photoconductor placed horizontally was rotated, glass beads were mixed with air, jetted under pressure, and collided with the photoconductor surface to roughen the surface. The blasting conditions were a glass bead diameter of 50 μm, an injection pressure of 2.5 kgf / cm, and a gun moving speed of 460 mm / min. Thereafter, the second coating was performed in the same manner as in Example 5.

In Example 11, an electrophotographic photosensitive member was produced in the same manner as in Example 11 except that the convex coating was changed to the following conditions.
Details of change: The amount of addition of the radical polymerizable compound having the charge transporting structure to 5.4 parts of the trifunctional or higher functional radical polymerizable monomer having no charge transporting structure in the second cross-linking convex coating liquid Changed to 12.6 parts.

In Example 11, an electrophotographic photosensitive member was produced in the same manner as in Example 11 except that the convex coating was changed to the following conditions.
Details of change: The amount of addition of the radical polymerizable compound having the charge transporting structure to 3.6 parts of the tri- or higher functional radical polymerizable monomer not having the charge transporting structure in the second crosslinking convex coating liquid Changed to 14.4 parts.

[Comparative Example 1]
In Example 2, an electrophotographic photosensitive member was prepared in the same manner as in Example 2 except that the convex coating was changed to the following conditions.
Details of change: Use the same cross-linked convex coating solution for the second surface layer as the first one.

[Comparative Example 2]
In Example 5, an electrophotographic photosensitive member was prepared in the same manner as in Example 5 except that the convex coating was changed to the following conditions.
Details of change: Use the same cross-linked convex coating solution as that used for the first round.

[Comparative Example 3]
In Example 5, an electrophotographic photosensitive member was prepared in the same manner as in Example 5 except that the convex coating was changed to the following conditions.
Details of change: The amount of addition of the radical polymerizable compound having the charge transporting structure to 1.8 parts of the trifunctional or higher functional radical polymerizable monomer having no charge transporting structure in the second cross-linking convex coating liquid Changed to 16.2 parts.

[Comparative Example 4]
In Example 8, an electrophotographic photosensitive member was produced in the same manner as in Example 8 except that the convex coating was changed to the following conditions.
Details of change: Use the same cross-linked convex coating solution as the first one for the second convex part.

[Comparative Example 5]
In Example 8, an electrophotographic photosensitive member was produced in the same manner as in Example 8 except that the convex coating was changed to the following conditions.
Details of change: The amount of addition of the radical polymerizable compound having the charge transporting structure to 1.8 parts of the trifunctional or higher functional radical polymerizable monomer having no charge transporting structure in the second cross-linking convex coating liquid Changed to 16.2 parts.

[Comparative Example 6]
This was compared with the conventional photoreceptor described in Patent Document 6.
[Underlayer]
That is, a photoreceptor having well-type irregularities on the surface as described in Patent Document 7 was prepared. First, honing is performed on an Al cylindrical support, the surface is roughened to a centerline roughness Ra = 0.18 μm, and the following undercoat layer coating solution is sublimed by 1.2 μm by dip coating. A layer was formed.
(Coating liquid for undercoat layer)
Polyvinyl butyral (ESREC BM-S, Sekisui Chemical) 4 parts acetylacetone zirconium butyrate 30 parts γ-aminopropyltrimethoxysilane 3 parts

[Charge generation layer]
Next, a charge generation layer coating solution having the following composition was prepared, and a 0.2 μm charge generation layer was formed by a dip coating method.
(Coating solution for charge generation layer)
Chlorgallium phthalocyanine having X-ray diffraction spectrum Bragg angles (2θ ± 0.2 °) of 7.4 °, 16.6 °, 25.5 °, and 28.3 ° as a charge generating substance. Dispersion obtained by dispersing the following mixture containing 4 hours in a sand mill 3 parts chlorogallium phthalocyanine 3 parts vinyl chloride-vinyl acetate copolymer (VMCH, Nippon Unicar) 2 parts 180 parts butyl acetate

[Charge transport layer]
Next, a charge transport layer coating solution having the following composition was prepared, and a 25 μm charge transport layer was formed by a dip coating method to obtain a photoreceptor composed of three layers.
(Coating liquid for charge transport layer)
N, N′-diphenyl-N, N-bis (3-methylphenyl)-[1,1′-bisphenyl] -4,4′-diamine 4 parts polycarbonate (Mitsubishi Chemical Corporation, Iupilon Z400) 6 parts tetrahydrofuran 60 parts 2,6-di-t-butyl-4-methylphenol After a composition of 0.2 parts or more was made into a solution, 3 parts of SiO ₂ particles (volume average particle size 500 nm, Tospearl 102 manufactured by Toshiba Silicone) were added. And dispersed to produce a charge transport layer coating solution.

[Convex]
Next, in accordance with Patent Document 6, a mold having a plurality of convex stampers attached thereto was prepared, and the shape was transferred to the photoconductor obtained by applying pressure. When observed with a laser microscope, a plurality of concave shapes with a diameter of about 0.7 μm, an average depth of about 0.5 μm, and an average pitch between wells of about 1.1 μm are formed on the surface of the photoreceptor. Confirmed that it was.

[Comparative Example 7]
In Example 1, an electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the convex coating was changed to the following conditions.
Contents of change: Second convex coating condition: drum rotation speed: 80 rpm, spray gun feed speed: 4.2 mm / s, discharge amount 0.6 ml / min, spraying pressure 3.0 kgf / mm ² , number of spraying; Change to once.

[Comparative Example 8]
In Example 1, an electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the convex coating was changed to the following conditions.
Contents of change: second convex coating condition: drum rotation speed: 80 rpm, spray gun feed speed: 16.5 mm / s, discharge amount 0.6 ml / min, spraying pressure 3.0 kgf / mm ² , number of spraying; Change to once.

  The surface shape of the obtained photoreceptor was measured with a surface roughness shape measuring instrument (Surfcom 1400D (measuring element DT43801) manufactured by Tokyo Seimitsu Co., Ltd., simply called “roughness meter”). FIG. 14 illustrates the measurement cross-section curve of Example 5 (vertical magnification: × 5000, horizontal magnification: × 10, measurement length: 12 mm). The roughness curve was obtained by removing the waviness curve from the measured cross-sectional curve, and Rz obtained therefrom was 2.89 μm. This is output according to the JISB0610 (2001) standard.

  The formed convex part resembled the shape that was created when a downward parabola was rotated about the axis. This measurement cross-sectional curve was a convex shape with the comb teeth facing upward. This is a characteristic when the surface layer is formed by spray coating the fine particle-containing coating solution. It was found that the plurality of convex portions were formed outward (Z-axis direction table) and independently from the surface of the photoreceptor. These convex portions are randomly arranged. In FIG. 14, it seems that there are spike-like convex portions due to the vertical and horizontal scales, but actually there are randomly convex portions having a smooth shape.

The above-described method for counting the number of convex portions was performed. First, in the range of 0 mm to 12 mm in the measurement length, the skirt portion closest to the layer before the surface layer coating was obtained, and the number of convex portions of 1.44 μm or more that is 1/2 Rz was obtained on the basis of this. There were 261 convex portions. However, shoulders and sub-peaks in the main peak were ignored. The average value of the heights of the 261 convex portions was 2.22 μm.
Measurement conditions are as follows: calculation standard: JIS 2001, measurement length: 12 mm, cut-off wavelength: 0.8 mm, measurement magnification × 20 K, measurement speed 0.06 mm, cut-off: R2C (phase compensation), slope correction least square method there were.

  FIG. 15 illustrates a surface shape measured with a laser microscope (VK-8500 manufactured by Keyence Corporation, objective 100 × lens, magnification ratio between vertical direction and plane direction: 50: 1) (Example 5). It has also been found that a plurality of protrusions are formed independently. The hem was smooth.

The photoreceptors of Examples 1 to 13 and Comparative Examples 1 to 8 manufactured as described above are mounted on a process cartridge for an electrophotographic apparatus, a semiconductor laser having an image exposure light source of 655 nm is used, a charging roller and a cleaning blade, Image output was performed with an image forming apparatus (remodeled from Ricoh Digital Printer IPSIO SP810) equipped with a zinc stearate zinc stearate bar, a zinc stearate coating brush, and a zinc stearate coating blade.
As the toner, a polymerized toner having a volume average particle diameter of 6 μm was used. The initial potential of the photoconductor was set so that Vd (dark portion potential) of the photoconductor was −800 V and Vl (light portion potential) was −200 V at room temperature and normal humidity (25 ° C., 60% RH).
The paper used was Ricoh Co., Ltd. 6200 paper (A4, T). The test chart is a mixture of photographic images and characters, and can evaluate the background portion, solid black portion, and halftone.

  The evaluation items are the evaluation of the state of the cleaning blade (mesh, chatter, wear), the state of the photoconductor (scratches and wear), and the output image (toner slipping) in the durability test. In both cases, the normal part was compared with the deteriorated part with an optical microscope. In the durability test, continuous image output of 50,000 sheets was performed. In the image evaluation, image deterioration of the image after 50,000 sheets (first to tenth sheets) was observed. The evaluation rank is shown below. Table 1 shows the evaluation results of Examples and Comparative Examples.

[(1) Observation of state of photoreceptor]
The surface of the electrophotographic photosensitive member is picked up by a surface roughness / contour shape measuring machine (Tokyo Seimitsu Co., Ltd., Surfcom 1400D): E-DT-S02A is attached, measurement length is 12 mm, measurement speed is 0.06 mm / s. Measured under conditions.
The change in the appearance of the electrophotographic photoreceptor surface after 50,000 sheets were passed was evaluated according to the following criteria.
(Surface observation evaluation)
○: Almost no change compared to the initial value △: Slight change compared to the initial value is recognized, but there is no problem ×: The initial shape remains almost unchanged

[(2) Image (toner slipping) evaluation]
Five halftone patterns and blank paper patterns depicting 4 dots x 4 dots in an 8 x 8 matrix with a pixel density of 600 dpi x 600 dpi are printed alternately and continuously, and the background standard of the blank paper pattern is visually checked as follows. It was evaluated with.
Rank ◎: No problem Rank ◯: There are very slight streaks or slight density unevenness in the output image Rank △: There are clear streaks or density unevenness due to toner slipping in the output image Rank ×: Output There are clear streaks or uneven density due to toner slipping at multiple positions in the image.

From the above evaluation results, in the electrophotographic photosensitive member having a cross-linked surface layer, a convex portion is formed on the surface layer, and the surface layer and the convex portion have the same charge transporting structure. A cross-linked product containing a structural unit is contained, and the convex part contains a structural part (B) having no charge transporting structure in addition to the structural unit (A), and contains the structural unit (A) The ratio is higher than that of the surface layer, and the structural part (A) is less than 90 wt% with respect to the total weight of the structural part (A) and the structural part (B), and the surface after the convex part is formed An electrophotographic photosensitive member characterized in that when the surface roughness of the layer is expressed in RzJIS, the number of convex portions having a height of ½ × RzJIS or more is 30 or more and 300 or less per 12 mm measurement length. Long-life image forming process that can maintain a good image for a long time, An image forming apparatus and a process cartridge for the image forming apparatus can be provided.
Further, an abnormal image was obtained when the number of convex portions at a measurement length of 12 mm was less than 30, and an abnormal image was obtained when the number of protrusions exceeded 300. Further, when the height of the convex portion exceeds 6 μm, there may be a slight defect in the output image.
In Comparative Example 1, since the content of the crosslinked body including the structural unit having the charge transporting structure of the convex portion was the same as that of the surface layer, the image density was uneven.
In Comparative Examples 2 and 4, there was no difference in the content of the cross-linked product including the structural unit having the charge transporting structure in the surface layer and the convex portion, and thus density unevenness occurred in the output image.
In Comparative Examples 3 and 5, since the content of the crosslinked body containing a structural unit having a charge transporting structure in the convex portion is very high, the strength of the convex portion itself is low, and the convex portion is destroyed after repeated use. The effect of the invention could not be obtained.
In Comparative Example 6, when image formation was repeated, large scratches were observed in which a plurality of recesses were connected by breaking the recesses in a part of the surface of the photoreceptor. Along with this, toner fusing and toner slipping occurred from this scratch. Moreover, the chip | tip of the cleaning blade corresponding to this damage | wound was recognized.
In Comparative Example 7, the number of convex portions was too small, so that the effect of the present invention was not sufficiently obtained.
In Comparative Example 8, since the number of the convex portions was too large, the blades were chipped, and the toner slipped out.

  Accordingly, in an electrophotographic photosensitive member having a crosslinked surface layer, a crosslinked body in which a convex portion is formed on the surface layer and the surface layer and the convex portion include a structural unit having the same charge transporting structure. The content of the cross-linked product in the convex portion is higher than that of the surface layer and has no charge transporting structure and the total weight of the cross-linked product having the charge transporting structure. When the surface roughness is less than 90 wt% and the surface roughness of the surface layer is expressed in RzJIS, the number of protrusions having a height of 1/2 × RzJIS or more is 30 or more and 300 or less per 12 mm measurement length. As a result, it has been found that it is possible to provide a photoreceptor that achieves both high durability and stable image quality. Therefore, it is possible to provide a high-performance and highly reliable image forming process, an image forming apparatus, and a process cartridge for an image forming apparatus that can provide a good image over a long period of time by using this photoconductor.

1 and FIG. 2 21... Conductive support 24... Subbing layer 25... Charge generation layer 26... Charge transport layer 28.

7 to 12 11... Electrophotographic photosensitive member 12... Charging means 13... Exposure means 14... Developing means 15. ..Print media (printing paper, OHP slide)
DESCRIPTION OF SYMBOLS 19 ... Fixing means 1A ... Static elimination means 1B ... Pre-cleaning exposure means 1C ... Driving means 1D ... First transfer means 1E ... Second transfer means 1F ... Intermediate transfer body

About FIG. 13 3C ... Lubricant supply means

Japanese Patent No. 2520270 Japanese Patent No. 3585197 JP 2001-166521 A Japanese Patent Publication No. 6-82221 JP 2002-196523 A JP 2001-66814 A JP 2007-233356 A Japanese Patent No. 3963473 JP 2007-233359 A JP 2005-99688 A Japanese Unexamined Patent Publication No. 7-92697

Claims (18)

  In the electrophotographic photosensitive member having a cross-linked surface layer, a convex portion is formed on the surface layer, and the surface layer and the convex portion are structural units (A) having the same charge transporting structure. The convex part contains the structural part (B) which does not have a charge transporting structure in addition to the structural unit (A), and the content of the structural unit (A) is the surface. Higher than the layer, and the structural part (A) is less than 90 wt% with respect to the total weight of the structural part (A) and the structural part (B), and the surface roughness of the surface layer after the formation of the convex part An electrophotographic photoreceptor, wherein the number of convex portions having a height of ½ × RzJIS or more is 30 or more and 300 or less per 12 mm measurement length when the thickness is expressed in RzJIS.   The electrophotographic photosensitive member according to claim 1, wherein the height of the convex portion is 6 μm or less as an average value with respect to a measurement length of 12 mm.   The electrophotographic photosensitive member according to claim 1, wherein the surface layer has a concave portion, and the convex portion is formed thereon.   4. The structural unit (A) is derived from a radical polymerizable compound having a site of the charge transporting structure and one or more radical polymerizable functional groups. An electrophotographic photoreceptor according to any one of the above.   The structure part (B) is mainly derived from a radical polymerizable material having no charge transport structure and having two or more radical polymerizable functional groups. The electrophotographic photosensitive member according to any one of the above.   6. The electrophotographic photosensitive member according to claim 1, wherein the structural unit (A) having a charge transporting structure is a triarylamine structure. The electrophotographic image according to any one of claims 1 to 6, wherein the crosslinked product is formed by crosslinking at least a radical polymerizable triarylamine compound represented by the following general formula (1). Photoconductor.

(Wherein, d, e and f are each an integer of 0 or 1, R ₁₃ represents a hydrogen atom or a methyl group, R ₁₄ and R ₁₅ represent a substituent other than a hydrogen atom, and a plurality of cases may be different. G and h each represent an integer of 0 to 3. Z is a single bond, a methylene group, an ethylene group,
Or

Represents. ) The electrophotographic photoreceptor according to claim 7, wherein the substituents R ₁₄ and R ₁₅ are alkyl groups having 1 to 6 carbon atoms.   9. The electrophotographic photosensitive member according to claim 1, wherein the convex portion is formed by a spray coating method.   10. The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer of the electrophotographic photosensitive member has a laminated structure of an undercoat layer, a charge generation layer, a charge transport layer, and a surface layer from the support side. body.   In the method for producing an electrophotographic photoreceptor having a cross-linked surface layer, the photoreceptor has a convex portion on the surface layer, and the surface layer and the convex portion have the same charge transporting structure. A cross-linked product containing a structural unit (A) is contained, and the convex part includes a structural part (B) having no charge transporting structure in addition to the structural unit (A), and the structural unit (A) Is higher than the surface layer, and the structural part (A) is less than 90 wt% with respect to the total weight of the structural part (A) and the structural part (B), and after the formation of the convex part When the surface roughness of the surface layer is represented by RzJIS, the number of convex portions having a height of ½ × RzJIS or more is 30 or more and 300 or less per 12 mm measurement length, and the convex portions are convex. Having a step of forming on the surface layer by spray coating a coating liquid for forming a part A method for producing an electrophotographic photosensitive member characterized by the above.   The said coating liquid contains the radically polymerizable compound which produces | generates the said structural unit (A), and the radically polymerizable material which mainly produces | generates the said structural part (B), It is characterized by the above-mentioned. A method for producing an electrophotographic photoreceptor.   The method for producing an electrophotographic photosensitive member according to claim 11, further comprising a step of forming a cross-linked convex portion by UV irradiation after the spray coating.   11. An image forming apparatus that forms an image by sequentially repeating at least charging, exposure, development, transfer, and cleaning steps, wherein the image forming apparatus comprises the electrophotographic photosensitive member according to claim 1. An image forming apparatus comprising:   The image forming apparatus according to claim 14, wherein polymerized toner is used in the developing process.   16. The image forming apparatus according to claim 14, further comprising means for scraping zinc stearate with a brush-like roller and inputting the zinc stearate to the electrophotographic photosensitive member.   17. The image forming apparatus according to claim 14, wherein the image forming apparatus has at least two colors or more of developing stations, is a tandem type, and further develops using polymerized toner.   11. An image forming apparatus according to claim 1, wherein the photosensitive member is an electrophotographic photosensitive member according to any one of 1 to 10 in a process cartridge that is attachable to and detachable from an image forming apparatus main body including at least a photosensitive member, a developing unit, and a cleaning unit. Process cartridge.

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