JP7425669B2 - Electrophotographic photoreceptors, process cartridges, and electrophotographic image forming devices - Google Patents

Description

The present invention relates to an electrophotographic photoreceptor, a process cartridge having the electrophotographic photoreceptor, and an electrophotographic image forming apparatus (hereinafter also referred to as "electrophotographic apparatus").

In recent years, electrophotographic devices have been developed that include an undercoat layer provided on a support and containing metal oxide particles, and a photosensitive layer provided on the undercoat layer and provided with a charge-generating substance and a charge-transporting substance. A photographic photoreceptor (organic electrophotographic photoreceptor) is used.
In particular, the thickness and material composition of the undercoat layer greatly affect the electrical properties of the electrophotographic photoreceptor. The electrical properties of the electrophotographic photoreceptor can be improved by a combination of the binder resin of the undercoat layer and metal oxide particles or organic compounds added mainly for the purpose of adjusting conductivity.

Surface-treated metal oxide particles are widely used to be contained in the undercoat layer for the purpose of stabilizing the dispersibility in the undercoat layer coating solution and the electrical characteristics of the electrophotographic photoreceptor. For example, in Patent Document 1, N-type semiconductor particles treated with a compound selected from alumina, silica, and zirconia are used in the undercoat layer, and then treated with dimethylpolysiloxane. This document describes an electrophotographic photoreceptor that exhibits excellent adhesiveness, reduced appearance of black spots, and excellent adhesion.

Furthermore, as a surface treatment for metal oxide particles, surface treatment using a silane coupling agent is also widely practiced. For example, Patent Document 2 discloses that an undercoat layer is made of tin oxide, zinc oxide, and titanium oxide that have been surface-treated with a silane coupling agent having an amino group as an organic functional group and a silane coupling agent having a fluorine-containing group. An electrophotographic photoreceptor is described in which, by using at least one selected metal oxide particle together with a binder resin, the particle dispersibility is good and the graininess of the image is excellent. Patent Document 3 discloses that in order to suppress bright area potential fluctuations and black spots in a high temperature and high humidity environment, the undercoat layer contains an alkyl group, a vinyl group, a methacryloyloxy group, and a specific urethane resin as organic functional groups. An electrophotographic photoreceptor containing metal oxide particles such as zinc oxide or titanium oxide particles treated with a silane coupling agent having either an acryloyloxy group is described.

Japanese Patent Application Publication No. 2008-76808 Japanese Patent Application Publication No. 2013-195962 JP2016-28266A

According to studies conducted by the present inventors, when surface-treating particles for the purpose of improving the dispersibility of the particles in the coating liquid for the undercoat layer and the electrical properties of the electrophotographic photoreceptor, the processing agent used and the particles and resin It has been found that depending on the combination, the surface waviness of the undercoat layer after the coating film dries becomes large. This surface waviness mainly occurs during the drying process of the paint film, and does not necessarily match the dispersibility in the undercoat layer coating solution (secondary particle size in the undercoat layer coating solution). do not. As the amount of silane coupling agent used to treat the particles increases, the dispersibility of the particles in the undercoat layer coating solution often improves, but on the other hand, the waviness of the surface of the undercoat layer, which is the coating film, worsens. There are cases where When the surface undulations of the undercoat layer become large, defects in the reproducibility of thin lines, such as thin lines being missing or interrupted, tend to occur, especially when outputting images at high resolution.

Therefore, an object of the present invention is to provide an electrophotographic photoreceptor that maintains good electrical characteristics and is less likely to cause defects in fine line reproducibility when outputting images at high resolution.

The above object is achieved by the present invention as follows. That is, the electrophotographic photoreceptor according to the present invention includes a support, an undercoat layer formed on the support, and a photosensitive layer formed on the undercoat layer. The layer contains a resin and surface-treated metal oxide particles, and the surface treatment is a surface treatment using a silane coupling agent having an isocyanurate group in the molecule.

According to the present invention, it is possible to provide an electrophotographic photoreceptor that maintains good electrical characteristics and is less likely to cause defects in fine line reproducibility when outputting images at high resolution.

1 is a diagram illustrating an example of a schematic configuration of an electrophotographic apparatus including a process cartridge having an electrophotographic photoreceptor. FIG. 2 is a diagram for explaining the layer structure of an electrophotographic photoreceptor. FIG. 2 is a diagram showing an example of a press-contact shape transfer processing device for forming a recess on the circumferential surface of an electrophotographic photoreceptor. (a) is a top view showing the mold used in Example 1 of the electrophotographic photoreceptor, (b) is a BB sectional view of the convex portion of the mold shown in (a), and (c) is a top view showing the mold used in Example 1 of the electrophotographic photoreceptor. FIG. 3 is a cross-sectional view taken along the line CC of the convex portion of the mold shown in FIG. FIG. 2 is a diagram showing an example of an apparatus for polishing a cylindrical electrophotographic photoreceptor using a polishing sheet.

The electrophotographic photoreceptor of the present invention includes a support, an undercoat layer formed on the support, and a photosensitive layer formed on the undercoat layer. It contains a resin and surface-treated metal oxide particles, and is characterized in that the surface treatment is a surface treatment using a silane coupling agent having an isocyanurate group in the molecule.

Why surface-treating metal oxide particles with a silane coupling agent that has an isocyanurate group in the molecule suppresses waviness on the surface of the undercoat layer and improves the reproducibility of fine lines in high-resolution image output. can be considered as follows. The undulations on the surface of the undercoat layer are mainly caused by the drying process of the coating film of the undercoat layer coating solution, that is, the process in which the solvent disappears, and the dispersion state of the metal oxide particles during this process. It is expected that it will depend heavily on A silane coupling agent having an isocyanurate group can be made compatible with an organic material (resin) due to the polarity of the isocyanurate group, and can improve the affinity between the metal oxide particles and the resin. For this reason, metal oxide particles surface-treated with a silane coupling agent having an isocyanurate group in the molecule remain highly dispersed in the coating film of the undercoat layer coating solution even during the process of disappearance of the solvent. Ru. As a result, it is presumed that waviness on the surface of the undercoat layer after drying of the coating film of the undercoat layer coating liquid is suppressed.

When the resin in the undercoat layer has a urethane bond, it is preferable because the affinity between the surface-treated metal oxide particles and the resin is further increased. Furthermore, it is preferable that the resin has an isocyanurate structure because the affinity between the surface-treated metal oxide particles and the resin is further increased.

Furthermore, when metal oxide particles having a small primary particle size are used, agglomeration is particularly likely to occur during the drying process because the metal oxide particles have high surface energy. Therefore, when using metal oxide particles with a small primary particle size, it is particularly useful to surface-treat the metal oxide particles with a silane coupling agent having an isocyanurate group.
Each constituent material of the undercoat layer of the present invention will be explained in detail below.

(metal oxide particles)
Examples of the metal oxide particles contained in the undercoat layer include particles of metal oxides such as titanium oxide, zinc oxide, tin oxide, zirconium oxide, and aluminum oxide. Particularly, titanium oxide particles are preferred from the viewpoint of electrical properties and environmental friendliness. Furthermore, from the viewpoint of dispersibility in the undercoat layer coating liquid and electrical properties of the electrophotographic photoreceptor, the metal oxide particles preferably have a primary particle number average particle diameter of 100 nm or less. In particular, it is preferable to use titanium oxide particles whose primary particles have a number average particle diameter of 1 nm or more and 15 nm or less because defects such as bright area potential fluctuations and image streaks can be easily suppressed. When using metal oxide particles with a small primary particle diameter of 1 nm or more and 15 nm or less, aggregation is likely to occur as described above, but aggregation can be suppressed by surface treatment with a specific silane coupling agent. Waviness on the surface of the undercoat layer can be suppressed.

Only one type of surface-treated metal oxide particles may be used, or particles with different types of metal oxides, particles with different types of silane coupling agents used for surface treatment, or particles with different types of surface-treated metal oxide particles may be used. Two or more kinds of metal oxide particles, such as those having different specific surface areas, can also be used in combination.
The content of metal oxide particles in the undercoat layer is preferably 0.5 times or more and 5.0 times or less in terms of mass ratio with respect to the content of the resin in the undercoat layer. Moreover, it is more preferable that it is 1.5 times or more and 3.0 times or less. If it is less than 0.5 times, sufficient conductivity may not be ensured. On the other hand, if the amount is more than 5.0 times, it may become difficult to form a uniform coating film.

(Silane coupling agent having an isocyanurate group in the molecule)
A silane coupling agent having an isocyanurate group in the molecule used for surface treatment of metal oxide particles has a reactive group (mainly an alkoxy group) for chemically bonding with the surface of metal oxide particles and an organic group that is silicon It has a structure that is bonded through atoms. The reactive group for chemically bonding with the surface of the metal oxide particles preferably has two (dialkoxy) or three (trialkoxy) alkoxy groups such as methoxy or ethoxy groups bonded to a silicon atom. The organic group is selected to have a functional group suitable for the purpose of surface treatment, and includes at least an isocyanurate group. As such a silane coupling agent, commercially available products include, for example, KBM-9659 (tris-(3-trimethoxy silylpropyl) isocyanurate).

The silane coupling agents represented by formulas (1-1) to (1-6) are shown below as specific examples of silane coupling agents having an isocyanurate group in the molecule, but molecules that can be used in the present invention The silane coupling agent having an isocyanurate group therein is not limited to these.

Among these, the silane coupling agent represented by formula (1-1) is preferable from the viewpoint of reaction speed with metal oxide particles and bond strength.

The amount of the silane coupling agent having an isocyanurate group in the molecule used for surface treatment is preferably 0.3% by mass or more and 15% by mass or less based on the total mass of the metal oxide particles. The amount used for optimal surface treatment also depends on the specific surface area of the metal oxide particles, and when the number average particle diameter of the primary particles of the metal oxide particles is 1 nm or more and 15 nm or less, the amount used is 3% by mass or more and 15% by mass or less. is preferred. When the number average particle diameter of the primary particles is 30 to 50 nm, it is preferably 0.5% by mass or more and 5% by mass or less. Further, when the number average particle diameter of the primary particles is 50 to 100 nm, it is preferably 0.3% by mass or more and 3% by mass or less. If the amount of the silane coupling agent having an isocyanurate group in the molecule used for surface treatment is too large, the electrical properties of the photoreceptor may deteriorate or the coatability of the charge generation layer formed on the undercoat layer may deteriorate. It may get worse.

Further, for the surface treatment of the metal oxide particles, a surface treatment agent other than the silane coupling agent having an isocyanurate group in the molecule may be used in combination. When a surface treatment agent other than a silane coupling agent having an isocyanurate group in the molecule is used in combination, it is preferable to appropriately reduce the amount of the silane coupling agent having an isocyanurate group in the molecule.

Any known method may be used for surface treating the metal oxide particles with a silane coupling agent. Examples include a dry method and a wet method. In the dry method, metal oxide particles are stirred in a high-speed mixer such as a Henschel mixer, and an alcohol aqueous solution, an organic solvent solution, or an aqueous solution containing a silane coupling agent is added to uniformly disperse the particles. It is then dried. In addition, in the wet method, metal oxide particles and a silane coupling agent are stirred in a solvent or dispersed using a sand mill using glass beads, etc. After dispersion, the solvent is removed by filtration or vacuum distillation. is removed. After removing the solvent, it is preferable to further bake at 100° C. or higher.

(resin)
The resins contained in the undercoat layer include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, epoxy resin, melamine resin, urethane resin, phenol resin, polyvinylphenol resin, alkyd resin, polyvinyl alcohol resin, polyethylene oxide resin, Examples include polypropylene oxide resin, polyamide resin, polyamic acid resin, polyimide resin, polyamideimide resin, and cellulose resin.

From the viewpoint of affinity with the silane coupling agent used in the particle surface treatment of the present invention, urethane resins, particularly urethane resins obtained by polymerizing an isocyanate compound and a polyvinyl acetal resin, are preferred.

Examples of the isocyanate compound include 2,4-tolylene diisocyanate (TDI), 2,6-tolylene diisocyanate, diphenylmethane-4,4'-diisocyanate (MDI), 1-isocyanato-3,3,5-trimethyl- Examples include 5-isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI), xylene diisocyanate (XDI), hexamethylene diisocyanate (HDI), HDI-trimethylolpropane adduct, HDI-isocyanurate, and HDI-biuret. Among these, aliphatic diisocyanates such as HDI and IPDI are preferred from the viewpoint of suppressing adsorption of water molecules onto metal oxide particles. Furthermore, from the viewpoint of affinity with a silane coupling agent having an isocyanurate group in the molecule, the central skeleton of the isocyanate compound is preferably an isocyanurate structure. In addition, in this specification, the isocyanurate skeleton that the silane coupling agent has in the molecule is referred to as an "isocyanurate group", and the isocyanurate skeleton contained in the resin is referred to as an "isocyanurate structure", but both represent the same skeleton. Needless to say.

Moreover, it is preferable that the isocyanate compound is blocked (stabilized). Blocking agents include oxime compounds such as formaldehyde oxime, acetaldoxime, methyl ethyl ketoxime, cyclohexanone oxime, acetone oxime, and methyl isobutyl ketoxime, Meldrum's acid, dimethyl malonate, diethyl malonate, di-n-butyl malonate, and acetic acid. Active methylene compounds such as ethyl and acetylacetone, as well as amine compounds, imine compounds, acid imide compounds, imidazole compounds, triazole compounds, acid amide compounds, lactam compounds, urea compounds, sulfites, and mercaptans. Examples include phenol-based compounds, pyrazole-based compounds, alcohol-based compounds, and the like.

[Electrophotographic photoreceptor]
Next, the structure of the electrophotographic photoreceptor of the present invention will be described.
The electrophotographic photoreceptor of the present invention has a support, an undercoat layer formed on the support, and a photosensitive layer on the undercoat layer. A conductive layer may be provided between the support and the undercoat layer. The photosensitive layer is preferably a laminated photosensitive layer having a charge generating layer containing a charge generating substance and a charge transporting layer containing a charge transporting substance, but may be a single layer photosensitive layer.

FIG. 2 is a diagram showing an example of the layer structure of an electrophotographic photoreceptor having laminated photosensitive layers.
In FIG. 2, the electrophotographic photoreceptor has a support 21, an undercoat layer 22, a charge generation layer 23, a charge transport layer 24, and a protective layer 25. In this case, the charge generation layer 23 and the charge transport layer 24 constitute a photosensitive layer, and the protective layer 25 becomes a surface layer. Moreover, when a protective layer is not provided, the charge transport layer 24 becomes a surface layer. In the present invention, it is preferable that the protective layer is a surface layer.

A method for manufacturing the electrophotographic photoreceptor of the present invention includes a method of preparing a coating liquid for each layer, which will be described later, and coating the layers in desired order, followed by drying. At this time, examples of methods for applying the coating liquid include dip coating, spray coating, inkjet coating, roll coating, die coating, blade coating, curtain coating, wire bar coating, ring coating, and the like. Among these, dip coating is preferred from the viewpoint of efficiency and productivity.
Each layer will be explained below.

<Support>
The support is preferably a conductive support having electrical conductivity. Further, the shape of the support includes a cylindrical shape, a belt shape, a sheet shape, and the like. Among these, a cylindrical support is preferred. Further, the surface of the support may be subjected to electrochemical treatment such as anodization, blasting treatment, cutting treatment, or the like.
Preferred materials for the support include metal, resin, and glass.
Examples of metals include aluminum, iron, nickel, copper, gold, stainless steel, and alloys thereof. Among these, an aluminum support using aluminum is preferable.
Further, conductivity may be imparted to the resin or glass by a process such as mixing or coating with a conductive material.

<Conductive layer>
A conductive layer may be provided on the support. By providing a conductive layer, it is possible to hide scratches and irregularities on the surface of the support, and to control the reflection of light on the surface of the support.
The conductive layer preferably contains conductive particles and a resin.

Examples of the material for the conductive particles include metal oxides, metals, carbon black, and the like.
Examples of metal oxides include zinc oxide, aluminum oxide, indium oxide, silicon oxide, zirconium oxide, tin oxide, titanium oxide, magnesium oxide, antimony oxide, bismuth oxide, and the like. Examples of metals include aluminum, nickel, iron, nichrome, copper, zinc, and silver.
Among these, it is preferable to use metal oxides as the conductive particles, and it is particularly preferable to use titanium oxide, tin oxide, and zinc oxide.
When using a metal oxide as the conductive particles, the surface of the metal oxide may be treated with a silane coupling agent or the like, or the metal oxide may be doped with an element such as phosphorus or aluminum or an oxide thereof.
Further, the conductive particles may have a laminated structure including a core particle and a coating layer covering the particle. Examples of the core material particles include titanium oxide, barium sulfate, and zinc oxide. Examples of the coating layer include metal oxides such as tin oxide.
Further, when using a metal oxide as the conductive particles, the volume average particle diameter thereof is preferably 1 nm or more and 500 nm or less, more preferably 3 nm or more and 400 nm or less.

Examples of the resin include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, silicone resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, and alkyd resin.
Further, the conductive layer may further contain a masking agent such as silicone oil, resin particles, and titanium oxide.

The average thickness of the conductive layer is preferably 1 μm or more and 50 μm or less, particularly preferably 3 μm or more and 40 μm or less.
The conductive layer can be formed by preparing a conductive layer coating solution containing each of the above-mentioned materials and a solvent, forming this coating film, and drying it. Examples of the solvent used in the coating solution include alcohol solvents, sulfoxide solvents, ketone solvents, ether solvents, ester solvents, and aromatic hydrocarbon solvents. Dispersion methods for dispersing conductive particles in the conductive layer coating solution include methods using a paint shaker, a sand mill, a ball mill, and a liquid collision type high-speed dispersion machine.

<Undercoat layer>
An undercoat layer is provided between the support or conductive layer and the photosensitive layer (charge generation layer or single layer type photosensitive layer).
The undercoat layer contains a resin and metal oxide particles whose surface has been treated with a silane coupling agent having an isocyanurate group in the molecule. Details regarding these components have been described above.

The undercoat layer may contain additives such as quinone compounds, fluorenone compounds, oxadiazole compounds, diphenoquinone compounds, anthraquinone compounds, benzophenone compounds, etc., for the purpose of improving electrical properties. In particular, at least one compound selected from the group consisting of the compound represented by formula (2) and the compound represented by formula (3) may be mixed with the metal oxide particles and the binder resin. R ^a1 to R ^a8 in formula (2) each independently represent a hydrogen atom, a hydroxy group, a halogen atom, an alkyl group, an alkoxy group, a phenyl group, or an amino group. R ^b1 to R ^b10 in formula (3) each independently represents a hydrogen atom, a hydroxy group, a halogen atom, an alkyl group, an alkoxy group, a phenyl group, or an amino group.

In particular, anthraquinone compounds having two or more hydroxy groups, that is, compounds represented by formula (2) in which two or more of R ^a1 to R ^a8 are hydroxy groups, and benzophenone compounds having three or more hydroxy groups, that is, R ^b1 - A compound represented by the formula (3) in which three or more of R ^b10 are hydroxy groups, is preferably at least one compound selected from the group consisting of.

Further, the undercoat layer may contain inorganic fine particles, organic resin particles, and a leveling agent for the purpose of suppressing interference fringes and improving film formability. The leveling agent is used to reduce problems that occur during the process of drying a coating film, and can also be used to suppress Benard cells caused by liquid convection.

The average thickness of the undercoat layer is preferably 0.5 μm or more and 30 μm or less, more preferably 2 μm or more and 30 μm or less.

The undercoat layer coating liquid for forming the undercoat layer of the present invention has metal oxide particles whose surface has been treated with a silane coupling agent having an isocyanurate group in the molecule dispersed together with a resin or its raw material and a solvent. It may be a coating liquid for an undercoat layer obtained by processing. Alternatively, a solution in which a resin or its raw material is dissolved is added to a dispersion obtained by dispersing metal oxide particles whose surface has been treated with a silane coupling agent having an isocyanurate group in the molecule, and further dispersion treatment is performed. A coating liquid for an undercoat layer obtained by

The undercoat layer of the present invention can be formed by applying a coating solution obtained by these methods to form a coating film, and drying and/or curing the coating solution. Examples of the solvent used in the coating solution include alcohol solvents, ketone solvents, ether solvents, ester solvents, and aromatic hydrocarbon solvents. Examples of the dispersion method include methods using a paint shaker, sand mill, ball mill, and liquid impingement type high-speed dispersion machine.

<Photosensitive layer>
The photosensitive layer of an electrophotographic photoreceptor is mainly classified into (1) a laminated photosensitive layer and (2) a single layer photosensitive layer. (1) The laminated photosensitive layer has a charge generation layer containing a charge generation substance and a charge transport layer containing a charge transport substance. (2) A single-layer type photosensitive layer has a photosensitive layer containing both a charge-generating substance and a charge-transporting substance.

(1) Laminated photosensitive layer The laminated photosensitive layer will be explained below.

(1-1) Charge Generating Layer The charge generating layer preferably contains a charge generating substance and a resin.

Examples of the charge generating substance include azo pigments, perylene pigments, polycyclic quinone pigments, indigo pigments, and phthalocyanine pigments. Among these, azo pigments and phthalocyanine pigments are preferred. Among the phthalocyanine pigments, oxytitanium phthalocyanine pigments, chlorogallium phthalocyanine pigments, and hydroxygallium phthalocyanine pigments are preferred.
The content of the charge generating substance in the charge generating layer is preferably 40% by mass or more and 85% by mass or less, more preferably 60% by mass or more and 80% by mass or less, based on the total mass of the charge generating layer. preferable.

Examples of resins include polyester resin, polycarbonate resin, polyvinyl acetal resin, polyvinyl butyral resin, acrylic resin, silicone resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, polyvinyl alcohol resin, cellulose resin, polystyrene resin, polyvinyl acetate resin. , polyvinyl chloride resin, etc. Among these, polyvinyl butyral resin is more preferred.

Further, the charge generation layer may further contain additives such as antioxidants and ultraviolet absorbers. Specific examples include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, and benzophenone compounds.

The average thickness of the charge generation layer is preferably 0.1 μm or more and 1 μm or less, more preferably 0.15 μm or more and 0.4 μm or less.

The charge generation layer can be formed by preparing a charge generation layer coating solution containing each of the above-mentioned materials and a solvent, forming this coating, and drying it. Examples of the solvent used in the coating solution include alcohol solvents, sulfoxide solvents, ketone solvents, ether solvents, ester solvents, and aromatic hydrocarbon solvents.

(1-2) Charge Transport Layer The charge transport layer preferably contains a charge transport substance and a resin.

Examples of the charge transport substance include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these substances. It will be done. Among these, triarylamine compounds and benzidine compounds are preferred.
The content of the charge transport substance in the charge transport layer is preferably 25% by mass or more and 70% by mass or less, more preferably 30% by mass or more and 55% by mass or less, based on the total mass of the charge transport layer. preferable.

Examples of the resin include polyester resin, polycarbonate resin, acrylic resin, and polystyrene resin. Among these, polycarbonate resins and polyester resins are preferred. As the polyester resin, polyarylate resin is particularly preferred.
The content ratio (mass ratio) of charge transport material and resin is preferably in the range of 4:10 to 20:10, more preferably in the range of 5:10 to 12:10.

Further, the charge transport layer may contain additives such as an antioxidant, an ultraviolet absorber, a plasticizer, a leveling agent, a slipperiness imparting agent, and an abrasion resistance improver. Specifically, hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oil, fluororesin particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, boron nitride particles. Examples include.

The average thickness of the charge transport layer is preferably 5 μm or more and 50 μm or less, more preferably 8 μm or more and 40 μm or less, and particularly preferably 10 μm or more and 30 μm or less.

The charge transport layer can be formed by preparing a charge transport layer coating solution containing each of the above-mentioned materials and a solvent, forming this coating film, and drying it. Examples of the solvent used in the coating liquid include alcohol solvents, ketone solvents, ether solvents, ester solvents, and aromatic hydrocarbon solvents. Among these solvents, ether solvents or aromatic hydrocarbon solvents are preferred.

(2) Single-layer photosensitive layer A single-layer photosensitive layer is formed by preparing a photosensitive layer coating solution containing a charge-generating substance, a charge-transporting substance, a resin, and a solvent, forming this coating, and drying it. can do. The charge-generating substance, charge-transporting substance, and resin are the same as those exemplified in the above “(1) Laminated photosensitive layer”.

<Protective layer>
In the present invention, a protective layer may be provided on the photosensitive layer. By providing a protective layer, durability can be improved.
The protective layer preferably contains conductive particles and/or a charge transport material and a resin.

Examples of the conductive particles include particles of metal oxides such as titanium oxide, zinc oxide, tin oxide, and indium oxide.
Examples of the charge transport substance include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these substances. Among these, triarylamine compounds and benzidine compounds are preferred.
Examples of the resin include polyester resin, acrylic resin, phenoxy resin, polycarbonate resin, polystyrene resin, phenol resin, melamine resin, and epoxy resin. Among these, polycarbonate resin, polyester resin, and acrylic resin are preferred.

Further, the protective layer may be formed as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group. Examples of reactions at that time include thermal polymerization reactions, photopolymerization reactions, radiation polymerization reactions, and the like. Examples of the polymerizable functional group possessed by the monomer having a polymerizable functional group include an acrylic group and a methacryl group. As the monomer having a polymerizable functional group, a material having charge transport ability may be used.

The protective layer may contain additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, slipperiness agents, and abrasion resistance improvers. Specifically, hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oil, fluororesin particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, boron nitride particles. Examples include.

The average thickness of the protective layer is preferably 0.5 μm or more and 10 μm or less, and preferably 1 μm or more and 7 μm or less.

The protective layer can be formed by preparing a protective layer coating solution containing each of the above-mentioned materials and a solvent, forming a coating film, and drying and/or curing the coating solution. Examples of the solvent used in the coating solution include alcohol solvents, ketone solvents, ether solvents, sulfoxide solvents, ester solvents, and aromatic hydrocarbon solvents.

[Process cartridge, electrophotographic image forming device]
The process cartridge of the present invention integrally supports the electrophotographic photoreceptor described above and at least one means selected from the group consisting of charging means, developing means, and cleaning means, and has an electrophotographic image forming apparatus. It is characterized by being detachable from the main body.

Further, the electrophotographic image forming apparatus of the present invention is characterized by having the electrophotographic photoreceptor, charging means, exposure means, developing means, and transfer means described above.

FIG. 1 shows an example of a schematic configuration of an electrophotographic image forming apparatus having a process cartridge 11 equipped with an electrophotographic photoreceptor.
A cylindrical electrophotographic photoreceptor 1 is rotated around a shaft 2 in the direction of the arrow at a predetermined circumferential speed. The surface of the electrophotographic photoreceptor 1 is charged to a predetermined positive or negative potential by the charging means 3. Although the figure shows a roller charging method using a roller type charging member, charging methods such as a corona charging method, a proximity charging method, and an injection charging method may be employed. The surface of the charged electrophotographic photoreceptor 1 is irradiated with exposure light 4 from an exposure means (not shown) to form an electrostatic latent image corresponding to target image information. The electrostatic latent image formed on the surface of the electrophotographic photoreceptor 1 is developed with toner contained in the developing means 5, and a toner image is formed on the surface of the electrophotographic photoreceptor 1. The toner image formed on the surface of the electrophotographic photoreceptor 1 is transferred onto a transfer material 7 by a transfer means 6. The transfer material 7 onto which the toner image has been transferred is conveyed to a fixing means 8, undergoes a toner image fixing process, and is printed out of the electrophotographic image forming apparatus. The electrophotographic image forming apparatus may include cleaning means 9 for removing adherents such as toner remaining on the surface of the electrophotographic photoreceptor 1 after transfer. Furthermore, a so-called cleaner-less system may be used in which the deposits are removed by a developing means or the like without separately providing a cleaning means. The electrophotographic image forming apparatus may include a static elimination mechanism that eliminates static electricity from the surface of the electrophotographic photoreceptor 1 using pre-exposure light 10 from a pre-exposure means (not shown). Furthermore, a guide means 12 such as a rail may be provided in order to attach and detach the process cartridge 11 of the present invention to and from the main body of the electrophotographic image forming apparatus.

The electrophotographic photoreceptor of the present invention can be used in laser beam printers, LED printers, copying machines, facsimile machines, and multifunctional machines thereof.

The present invention will be explained in more detail below by giving specific examples. However, the present invention is not limited to these. In the examples, "part" means "part by mass", and "%" means "% by mass".

(Example 1)
- Support A cylindrical aluminum cylinder (JIS-A3003, aluminum alloy, diameter 30 mm, length 357.5 mm, wall thickness 0.7 mm) was used as a support (conductive support).

・Formation of undercoat layer 100 parts of inorganic silica-coated titanium oxide particles (product name: TKP-101, manufactured by Teika Co., Ltd., number average particle diameter of primary particles: 6 nm) as metal oxide particles are stirred and mixed with 500 parts of toluene. did. To this solution, 10 parts of tris-(3-trimethoxysilylpropyl)isocyanurate (trade name: KBM-9659, manufactured by Shin-Etsu Chemical Co., Ltd.), which is a silane coupling agent, was added as a surface treatment agent, and the mixture was heated for 5 hours. Stirred. Thereafter, toluene was distilled off under reduced pressure, and the particles were dried by heating at 130° C. for 4 hours to obtain inorganic silica-coated titanium oxide particles whose surface was treated with a silane coupling agent having an isocyanurate group in the molecule.
Next, 5 parts of polyvinyl butyral (trade name: BM-1, manufactured by Sekisui Chemical Co., Ltd.) and 5 parts of blocked isocyanate (trade name: Duranate TPA-B80E, manufactured by Asahi Kasei Chemicals Co., Ltd.) were added to 28 parts of methyl ethyl ketone. 1 part and 28 parts of 1-butanol. To this solution were added 25 parts of the above-mentioned surface-treated inorganic silica-coated titanium oxide particles and 0.5 part of 2,3,4-trihydroxybenzophenone (manufactured by Tokyo Chemical Industry Co., Ltd.). These were placed in a sand mill using glass beads with a diameter of 0.8 mm, and dispersed for 3 hours in an atmosphere of 23±3°C. In addition, the said blocked isocyanate is hexamethylene diisocyanate (HDI) which has an isocyanurate structure.
After the dispersion treatment, 0.004 part of silicone oil (trade name: SH28PA, manufactured by Dow Corning Toray Industries, Inc.) was added and stirred to prepare a coating solution for an undercoat layer.
This undercoat layer coating solution is applied onto the above support by dip coating to form a coating film, and the resulting coating film is dried at 160°C for 60 minutes to form an undercoat layer with a film thickness of 17 μm. did.

を、シクロヘキサノン１００部にポリビニルブチラール（商品名：エスレックＢＸ－１、積水化学工業（株）製）２部を溶解させた液に加えた。これらを直径１ｍｍのガラスビーズを用いたサンドミルに入れ、２３±３℃の雰囲気下で１時間分散処理した。
分散処理後、酢酸エチル１００部を加えることによって、電荷発生層用塗布液を調製した。
この電荷発生層用塗布液を上記で形成した下引き層上に浸漬塗布して塗膜を形成し、得られた塗膜を１０分間９０℃で乾燥させることによって、膜厚が０．１９μｍの電荷発生層を形成した。 ・Formation of charge generation layer 4 parts of hydroxygallium phthalocyanine crystal (charge generation substance) in a crystalline form having strong peaks at 7.4° and 28.1° of Bragg angle 2θ±0.2° in CuKα characteristic X-ray diffraction; and 0.04 part of a compound represented by formula (A)

was added to a solution prepared by dissolving 2 parts of polyvinyl butyral (trade name: S-LEC BX-1, manufactured by Sekisui Chemical Co., Ltd.) in 100 parts of cyclohexanone. These were placed in a sand mill using glass beads with a diameter of 1 mm, and dispersed for 1 hour in an atmosphere of 23±3°C.
After the dispersion treatment, 100 parts of ethyl acetate was added to prepare a charge generation layer coating solution.
This charge generation layer coating solution was applied by dip coating onto the undercoat layer formed above to form a coating film, and the resulting coating film was dried at 90°C for 10 minutes to give a film thickness of 0.19 μm. A charge generation layer was formed.

ポリカーボネート（商品名：ユーピロンＺ４００、三菱エンジニアリングプラスチックス（株）製、ビスフェノールＺ型のポリカーボネート）１００部、式（Ｅ）で示される構造単位を有するポリカーボネート（粘度平均分子量Ｍｖ：２００００）０．０２部

を、ｏ－キシレン２７２部、安息香酸メチル２５６部およびジメトキシメタン２７２部の混合溶剤に溶解させることによって、電荷輸送層用塗布液を調製した。
この電荷輸送層用塗布液を上記で形成した電荷発生層上に浸漬塗布して塗膜を形成し、得られた塗膜を５０分間１１５℃で乾燥させることによって、膜厚１８μｍの電荷輸送層を形成した。 ・Formation of charge transport layer: 60 parts of the compound represented by formula (B) (charge transport substance), 30 parts of the compound represented by formula (C) (charge transport substance), the compound represented by formula (D) (charge transport substance) ) 10 copies,

100 parts of polycarbonate (trade name: Iupilon Z400, manufactured by Mitsubishi Engineering Plastics Co., Ltd., bisphenol Z type polycarbonate), 0.02 parts of polycarbonate having a structural unit represented by formula (E) (viscosity average molecular weight Mv: 20000)

A coating solution for a charge transport layer was prepared by dissolving the following in a mixed solvent of 272 parts of o-xylene, 256 parts of methyl benzoate, and 272 parts of dimethoxymethane.
This charge transport layer coating solution was dip coated onto the charge generation layer formed above to form a coating film, and the resulting coating film was dried at 115°C for 50 minutes to form a charge transport layer with a thickness of 18 μm. was formed.

（式（Ｆ）中、０．５は２つの構造単位のモル比（共重合比）である。）
この保護層用塗布液を上記で形成した電荷輸送層上に浸漬塗布して塗膜を形成し、得られた塗膜を５分間４０℃で乾燥させた。乾燥後、窒素雰囲気下にて、加速電圧７０ＫＶ、吸収線量１５ｋＧｙの条件で１．６秒間電子線を塗膜に照射した。その後、窒素雰囲気下にて、塗膜の温度が１３５℃になる条件で１５秒間加熱処理を行った。なお、電子線の照射から１５秒間の加熱処理までの酸素濃度は１５ｐｐｍであった。次に、大気中において、塗膜の温度が２５℃になるまで自然冷却し、その後、塗膜が１０５℃になる条件で１時間加熱処理を行い、膜厚５μｍの保護層（表面層）を形成した。 ・Formation of protective layer 1.65 parts of a resin having a structural unit represented by formula (F) (weight average molecular weight: 130,000) was mixed with 1,1,2,2,3,3,4-heptafluorocyclopentane. (Product name: Zeorola H, manufactured by Nippon Zeon Co., Ltd.) and dissolved in a mixed solvent of 40 parts and 55 parts of 1-propanol. Thereafter, a solution containing 30 parts of tetrafluoroethylene resin powder (trade name: Lublon L-2, manufactured by Daikin Industries, Ltd.) was mixed with a high-pressure dispersion machine (trade name: Microfluidizer M-110EH, manufactured by Microfluidics Co., Ltd.). ) to obtain a dispersion.
Thereafter, 52.0 parts of a hole transporting compound represented by formula (G), 2.0 parts of a compound represented by formula (H) (compound name: vinyl laurate, manufactured by Sigma-Aldrich), and formula (I) 16.0 parts of the indicated compound (trade name: Aronix M-315, manufactured by Toagosei Co., Ltd.), 0.75 parts of a siloxane-modified acrylic compound (trade name: BYK-3550, manufactured by BYK Chemie Japan Co., Ltd.), 1 , 35 parts of 1,2,2,3,3,4-heptafluorocyclopentane, and 15 parts of 1-propanol were added to the dispersion, and a Polyflon filter (product name: PF-040, manufactured by Advantech Toyo Co., Ltd.) was added. A protective layer coating solution was prepared.

(In formula (F), 0.5 is the molar ratio (copolymerization ratio) of the two structural units.)
This protective layer coating solution was applied by dip coating onto the charge transport layer formed above to form a coating film, and the resulting coating film was dried at 40° C. for 5 minutes. After drying, the coating film was irradiated with an electron beam for 1.6 seconds under the conditions of an acceleration voltage of 70 KV and an absorbed dose of 15 kGy in a nitrogen atmosphere. Thereafter, heat treatment was performed for 15 seconds in a nitrogen atmosphere at a temperature of 135°C. Note that the oxygen concentration from electron beam irradiation to 15 seconds of heat treatment was 15 ppm. Next, the coating film was naturally cooled in the air until the temperature reached 25°C, and then heat-treated for 1 hour at a temperature of 105°C to form a protective layer (surface layer) with a thickness of 5 μm. Formed.

The surface of the produced electrophotographic photoreceptor can also be subjected to surface treatment in order to reduce the frictional force between the electrophotographic photoreceptor and a member that may come into contact with the surface of the photoreceptor. Surface processing includes polishing processing, shape processing, and the like.
In Example 1, as a shape processing treatment on the surface of an electrophotographic photoreceptor, recesses were formed by mold pressure shape transfer.

[Formation of recesses by mold pressure shape transfer]
A press-contact shape transfer processing apparatus having a configuration shown in FIG. 3, including a mold 32, a pressure member 33, and a support member 34, is equipped with a mold having a shape roughly shown in FIG. (The maximum length in the axial direction when the convex part on the mold is viewed from above, that is, the length in the BB cross section) is 30 μm, and the maximum length Y of the mold (when the convex part on the mold is seen from above) is 30 μm. The maximum length in the circumferential direction (that is, the length in the CC cross-sectional view) of the mold is 75 μm, the maximum height H of the mold is 1.0 μm, and the area ratio is 60%). The peripheral surface of the body 31 was processed. During processing, the temperature of the electrophotographic photoreceptor and the mold was controlled so that the temperature of the circumferential surface of the electrophotographic photoreceptor was 120°C, and the electrophotographic photoreceptor and the pressure member were pressed together with a pressure of 7.0 MPa in the direction of the arrow. At the same time, the electrophotographic photoreceptor was rotated in the circumferential direction to form a recessed portion over the entire circumferential surface of the electrophotographic photoreceptor.
As described above, the electrophotographic photoreceptor of Example 1 was produced.

(Example 2)
An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that the solvent used to prepare the coating solution for the undercoat layer was changed to a mixed solvent of 28 parts of methanol and 28 parts of 1-methoxy-2-propanol.

(Example 3)
The metal oxide particles used in the preparation of the coating solution for the undercoat layer were changed from inorganic silica-coated titanium oxide particles to titanium oxide particles (trade name: AMT100, manufactured by Teika Co., Ltd., number average particle diameter of primary particles: 6 nm). The surface treatment was performed in the same manner as in Example 1 except for the following changes, and an electrophotographic photoreceptor was produced.

(Examples 4 and 5)
An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that the amount of the silane coupling agent having an isocyanurate group in the molecule was changed as shown in Table 1.

(Example 6)
Example except that the metal oxide particles used to prepare the coating solution for the undercoat layer were changed to titanium oxide particles (product name: TKP102, manufactured by Teika Co., Ltd., number average particle diameter of primary particles: 15 nm). An electrophotographic photoreceptor was produced in the same manner as in Example 1.

(Example 7)
The metal oxide particles used in the preparation of the coating solution for the undercoat layer were changed to titanium oxide particles (product name: AMT600, manufactured by Teika Co., Ltd., number average particle diameter of primary particles: 30 nm), and the particles contained isocyanate in the molecule. An electrophotographic photoreceptor was prepared by surface treatment in the same manner as in Example 1, except that the amount of the silane coupling agent having a nurate group was changed as shown in Table 1.

(Example 8)
An electrophotographic photoreceptor was produced in the same manner as in Example 7 except that the thickness of the undercoat layer was changed to 30 μm.
(Example 9)
The metal oxide particles used in the preparation of the coating solution for the undercoat layer were changed to zinc oxide particles (product name: MZ-300, manufactured by Teika Co., Ltd., number average particle diameter of primary particles: 35 nm), and An electrophotographic photoreceptor was prepared by surface treatment in the same manner as in Example 1, except that the amount of the silane coupling agent having an isocyanurate group was changed as shown in Table 1.

(Example 10)
Same as Example 7 except that the blocked isocyanate used to prepare the coating solution for the undercoat layer was changed to blocked isocyanate (trade name: Burnock D-550, manufactured by DIC Corporation, adduct type of aromatic isocyanate). An electrophotographic photoreceptor was produced.

(Example 11)
An electrophotographic photoreceptor was produced in the same manner as in Example 7, except that the resin for the undercoat layer was changed from urethane resin to phenol resin. That is, the undercoat layer was formed as follows.
As the metal oxide particles, titanium oxide particles (30 nm), which were surface-treated with a silane coupling agent having an isocyanurate group in the molecule, as in Example 7, were used.
10 parts of phenol resin (trade name: Pryophen J-325, manufactured by Dainippon Ink & Chemicals Co., Ltd., resin solid content 60%) and 35 parts of 1-methoxy-2-propanol were mixed, and this solution was subjected to the above surface treatment. 15 parts of titanium oxide particles and 0.3 part of 2,3,4-trihydroxybenzophenone (manufactured by Tokyo Chemical Industry Co., Ltd.) were added. These were placed in a sand mill using glass beads with a diameter of 0.8 mm, and dispersed for 3 hours in an atmosphere of 23±3°C.
After dispersion treatment, 0.004 part of silicone oil (trade name: SH28PA, manufactured by Dow Corning Toray Industries, Inc.) was added and stirred, and the solid content was reduced with a mixed solution of 1-methoxy-2-propanol:methanol = 2:1. A coating solution for an undercoat layer was prepared by diluting the solution to 52%.
This undercoat layer coating solution is applied by dip coating onto a surface-treated aluminum cylinder to form a coating film, and the resulting coating film is dried at 100°C for 10 minutes to form an undercoat layer with a thickness of 3 μm. was formed.
This undercoat layer coating solution was applied onto the support by dip coating to form a coating film, and the resulting coating film was dried at 140° C. for 30 minutes to form an undercoat layer with a film thickness of 17 μm. .

(Example 12)
As a support, the surface of the cylindrical aluminum cylinder used in Example 1 was subjected to cutting treatment to suppress interference fringes. The cutting conditions were as follows: using a cutting tool with an R of 0.1, the spindle rotation speed = 10,000 rpm, and the feeding speed of the cutting tool was continuously varied in the range of 0.03 to 0.06 mm/rpm.
An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that the aluminum cylinder subjected to the cutting treatment as described above was used as a support and the thickness of the undercoat layer was changed to 5 μm.

(Example 13)
As a support, the cylindrical aluminum cylinder used in Example 1, the surface of which had been honed as described below, was used.
A cylindrical aluminum cylinder was mounted on a lathe, and cut using a diamond sintering tool so that the outer diameter was 30.0±0.02 mm, the runout accuracy was 15 μm, and the surface roughness Rz was 0.2 μm. At this time, the spindle rotation speed was 3000 rpm, the feed rate of the cutting tool was 0.3 mm/rev, and the machining time was 24 seconds, excluding the workpiece attachment and detachment.
The surface roughness was measured in accordance with JIS B 0601 using a surface roughness meter Surfcoder SE3500 manufactured by Kosaka Institute, with a cutoff of 0.8 mm and a measurement length of 8 mm.
The obtained aluminum cut tube was subjected to liquid honing treatment using a liquid (wet type) honing device under the following conditions.

(Liquid honing conditions)
Abrasive grains = spherical alumina beads average particle size 30μm
(Product name: CB-A30S, manufactured by Showa Denko Co., Ltd.)
Suspending medium = water Abrasive material/suspending medium = 1/9 (volume ratio)
Rotation speed of aluminum cutting tube = 1.67S ^-1
Air blowing pressure = 0.15MPa
Gun movement speed = 13.3mm/sec.
Distance between gun nozzle and aluminum tube = 200mm
Honing abrasive discharge angle = 45°
Number of times of polishing liquid projection = 1 time (one way)
The cylinder surface roughness after honing was Rmax 2.53 μm, Rz 1.51 μm, Ra 0.23 μm, and Sm 34 μm. Immediately after performing the wet honing treatment as described above, the aluminum cylinder was once immersed in a dipping tank filled with pure water, pulled out, and subjected to a shower cleaning with pure water before the cylinder was dried. Thereafter, hot water at 85° C. was discharged from a discharge nozzle and brought into contact with the inner surface of the substrate to dry the outer surface. Thereafter, the inner surface of the substrate was dried naturally.
An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that the aluminum cylinder whose surface was treated as described above was used as a support and the thickness of the undercoat layer was changed to 5 μm.

(Example 14)
The resin for the undercoat layer was changed from urethane resin to polyamide resin. That is, on an aluminum cylinder whose surface had been treated in the same manner as in Example 13, an undercoat layer was formed in the following manner.
As the metal oxide particles, inorganic silica-coated titanium oxide particles (6 nm), which were surface-treated with a silane coupling agent having an isocyanurate group in the molecule, as in Example 13, were used.
6 parts of N-methoxymethylated 6-nylon resin (trade name: Torezin EF-30T, manufactured by Nagase ChemteX, methoxymethylation rate: 28 to 33% by mass) was dissolved in 63 parts of methanol and 31 parts of 1-butanol. 15 parts of the surface-treated titanium oxide particles were added to this solution, placed in a sand mill using glass beads with a diameter of 0.8 mm, and dispersed in an atmosphere of 23±3° C. for 3 hours.
This undercoat layer coating solution is applied by dip coating onto a surface-treated aluminum cylinder to form a coating film, and the resulting coating film is dried at 100°C for 10 minutes to form an undercoat layer with a thickness of 3 μm. was formed.

(Example 15 and 16)
A conductive layer was first provided on the support as follows.
57 parts of titanium oxide particles having a coating layer (product name: Pastran LRS, manufactured by Mitsui Kinzoku Mining Co., Ltd.), 35 parts of resol type phenolic resin (product name: Phenolite J-325, manufactured by DIC Corporation, solid content 60 % methanol solution) and 33 parts of 2-methoxy-1-propanol were dispersed for 3 hours in a sand mill using glass beads with a diameter of 1 mm to prepare a dispersion. The average particle size of the powder contained in this dispersion was 0.30 μm. A solution prepared by dispersing 8 parts of a silicone resin (trade name: Tospearl 120, manufactured by Momentive Performance Materials Japan LLC) in 8 parts of 2-methoxy-1-propanol was added to this dispersion. Furthermore, 0.008 parts of silicone oil (trade name: SH28PA, manufactured by Dow Corning Toray Industries, Inc.) was added. The dispersion thus prepared was applied onto the above aluminum cylinder by dipping, and the coating was cured by heating in a hot air dryer adjusted to 150°C for 30 minutes to harden the coating film of the dispersion. , a conductive layer with a thickness of 30 μm was formed.
An electrophotographic photoreceptor was formed in the same manner as in Example 1, except that an undercoat layer having the thickness shown in Table 1 was formed on the conductive layer formed above.

(Example 17)
An electrophotographic photoreceptor was produced in the same manner as in Example 12, except that the processing method for the protective layer was changed to the polishing process shown below.
[Polishing of electrophotographic photoreceptor before surface polishing]
Using the polishing apparatus shown in FIG. 5, the surface of the electrophotographic photoreceptor before surface shape formation was polished under the following conditions.
Feeding speed of polishing sheet 51: 400mm/min
Rotation speed of electrophotographic photoreceptor 54: 450 rpm
Pushing the electrophotographic photoreceptor 54 into the backup roller 53; 3.5 mm
Rotation direction of polishing sheet 51 and electrophotographic photoreceptor; with backup roller 53; outer diameter 100 mm, Asker C hardness 25
The polishing sheet 51 to be attached to the polishing apparatus was prepared by mixing polishing abrasive grains used in GC3000 and GC2000 manufactured by Riken Corundum Co., Ltd.
GC3000 (polishing sheet surface roughness Ra0.83μm)
GC2000 (polishing sheet surface roughness Ra1.45μm)
Polishing sheet 51 (polishing sheet surface roughness Ra 1.12 μm)
The polishing time using the polishing sheet 51 was 20 seconds.

(Comparative example 1)
The same procedure was carried out except that the silane coupling agent having an isocyanurate group in the molecule used in Example 1 was changed to hexamethyldisilazane (HMDS, trade name: SZ-31, manufactured by Shin-Etsu Chemical Co., Ltd.). An electrophotographic photoreceptor was produced in the same manner as in Example 1.
(Comparative example 2)
The same procedure was carried out except that the silane coupling agent having an isocyanurate group in the molecule used in Example 7 was changed to hexamethyldisilazane (HMDS, trade name: SZ-31, manufactured by Shin-Etsu Chemical Co., Ltd.). An electrophotographic photoreceptor was produced in the same manner as in Example 7.

(Comparative example 3)
The silane coupling agent having an isocyanurate group in the molecule used in Example 7 was replaced with N-2-(aminoethyl)-3-aminopropyltrimethoxysilane (trade name: KBM-603, Shin-Etsu Chemical Co., Ltd.) An electrophotographic photoreceptor was produced in the same manner as in Example 7, except that the electrophotographic photoreceptor was changed to a material (manufactured by Co., Ltd.). Note that N-2-(aminoethyl)-3-aminopropyltrimethoxysilane is indicated as "aminosilane" in Table 1.

<Evaluation of electrophotographic photoreceptor>
As an electrophotographic device for evaluation, a modified copying machine (trade name: iR-ADVC5051) manufactured by Canon Inc. was used to conduct the evaluation as follows.

<Potential fluctuation>
First, the electrophotographic device and the electrophotographic photoreceptor were left in an environment with a temperature of 23° C. and a humidity of 50% RH for 48 hours or more, and then the electrophotographic photoreceptors of Examples and Comparative Examples were mounted on the black station of the electrophotographic device. .
The surface potential of the electrophotographic photoreceptor was measured by removing the developing cartridge from the evaluation device and inserting the potential measuring device into its position. The potential measuring device has a configuration in which a potential measuring probe is arranged at a developing position of a developing cartridge. The position of the potential measurement probe with respect to the electrophotographic photoreceptor was at the center of the electrophotographic photoreceptor in the generatrix direction, and the gap from the surface of the electrophotographic photoreceptor was 3 mm.
To measure the potential, first, the applied voltage was adjusted so that the initial dark area potential (VDa) was -700V, and the image exposure amount was adjusted so that the initial bright area potential (VLa) due to laser exposure irradiation was -300V. . These operations were performed in the same manner for each electrophotographic photoreceptor to be evaluated.
Subsequently, a developing cartridge was attached to the evaluation apparatus, and 5,000 images were output. After outputting 5,000 images, the developing cartridge was replaced with a potential measuring device, and the bright area potential (VLb) after repeated use was measured.
Then, check the amount of variation between the initial dark area potential (VDa) and initial light area potential (VLa) before paper feeding and the initial dark area potential (VDb) and light area potential (VLb) after paper feeding, and The dark area potential variation ΔVD and the bright area potential variation ΔVL were defined. When both ΔVD and ΔVL are within ±15V, it is designated as A, when it is within ±30V, it is designated as B, and when the fluctuation is larger than 30V, it is designated as C. The results are shown in Table 1.

<Reproducibility of fine lines>
First, the electrophotographic apparatus and the electrophotographic photoreceptor were left in an environment at a temperature of 23° C. and a humidity of 50% RH for 48 hours or more, and then the electrophotographic photoreceptors of Examples and Comparative Examples were installed in the cyan station of the electrophotographic apparatus. .
Next, the conditions of the charging device and image exposure device are set so that the dark area potential (Vd) of the electrophotographic photoreceptor is -700V and the light area potential (Vl) is -200V, and the initial potential of the electrophotographic photoreceptor is set. It was adjusted.
The reproducibility of fine lines was evaluated by adjusting the development contrast so that the density was 1.40±0.10. A test chart was created in which line images (1 line, 3 spaces on A4 portrait size paper) were arranged at an output resolution of 1200 dpi. The reproducibility of fine lines of the electrophotographic photoreceptor was evaluated using the output image of the test chart. Specifically, the output image was read at a resolution of 1600 dpi using a scanner (trade name: CanoScan 9900F, manufactured by Canon Inc.), and the read image data and the original data of the test chart were compared. The obtained results were ranked according to the following criteria. The results are shown in Table 1. Ranks A to C are acceptable.
A: Clear image with excellent reproducibility of fine lines B: Clear image with excellent reproducibility of fine lines C: Slight decrease in reproducibility of fine lines and uniformity of image, but not a problem in practical use Image without image D: Image in which fine line reproducibility and image uniformity are significantly reduced

It can be seen that the photoreceptor of the example maintains good electrical characteristics and has no problem in reproducibility of fine lines when outputting images at high resolution.

1 Electrophotographic photoreceptor 2 Axis 3 Charging means 4 Exposure light 5 Developing means 6 Transfer means 7 Transfer material 8 Fixing means 9 Cleaning means 10 Pre-exposure light 11 Process cartridge 12 Guide means

21 Support 22 Undercoat layer 23 Charge generation layer 24 Charge transport layer 25 Protective layer

31 Electrophotographic photoreceptor 32 Mold 33 Pressure member 34 Support member

51 Polishing sheet 53 Backup roller 54 Electrophotographic photoreceptor

Claims (8)

In an electrophotographic photoreceptor having a support, an undercoat layer formed on the support, and a photosensitive layer formed on the undercoat layer, the undercoat layer comprises a resin and a surface-treated metal oxide. 1. An electrophotographic photoreceptor, characterized in that the surface treatment is a surface treatment using a silane coupling agent having an isocyanurate group in the molecule. The electrophotographic photoreceptor according to claim 1, wherein the silane coupling agent is tris-(3-trimethoxysilylpropyl)isocyanurate. The electrophotographic photoreceptor according to claim 1 or 2, wherein the resin is a urethane resin. The electrophotographic photoreceptor according to claim 3, wherein the urethane resin contains an isocyanurate structure. The electrophotographic photoreceptor according to any one of claims 1 to 4, wherein the metal oxide particles are titanium oxide particles. The electrophotographic photoreceptor according to any one of claims 1 to 5, wherein the number average particle diameter of the primary particles of the metal oxide particles is 1 nm or more and 15 nm or less. The electrophotographic photoreceptor according to any one of claims 1 to 6 and at least one means selected from the group consisting of a charging means, a developing means, and a cleaning means are integrally supported, and an electrophotographic image forming apparatus is provided. A process cartridge that can be attached to and detached from the main body of the forming device. An electrophotographic image forming apparatus comprising the electrophotographic photoreceptor according to any one of claims 1 to 6, charging means, exposure means, developing means, and transfer means.

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