Electrophotographic photoreceptor, process cartridge, and electrophotographic device

Abstract

To provide an electrophotographic photoreceptor that offers superior cleanability and durability and reduced residual potential.SOLUTION: An electrophotographic photoreceptor is provided, comprising a surface layer containing vinyl resin particles surface-treated with a specific compound.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an electrophotographic photoreceptor, a process cartridge having the electrophotographic photoreceptor, and an electrophotographic apparatus having the electrophotographic photoreceptor.

Background Art

[0002] As an electrophotographic photoreceptor mounted in an electrophotographic apparatus, one containing an organic photoconductive substance (charge generating substance) is widely used. In recent years, for the purpose of extending the life of the electrophotographic photoreceptor and improving the image quality during repeated use, improvement in the mechanical durability (abrasion resistance) of the electrophotographic photoreceptor has been demanded. As a technique for improving the abrasion resistance of an electrophotographic photoreceptor, there is a method of reducing the friction between the surface layer of the electrophotographic photoreceptor and a contact member such as a cleaning blade by containing resin particles in the surface layer. Patent Document 1 discloses a technique of forming a surface layer using a dispersion liquid of fluorine atom-containing resin particles such as polytetrafluoroethylene resin particles as a coating liquid for the surface layer. Also, considering the impact on the environment, an electrophotographic photoreceptor composed of a material not containing fluorine atoms is desirable. Patent Document 2 discloses a technique of reducing the friction between the surface layer and a contact member such as a cleaning blade by using resin particles not containing fluorine atoms. Also, Patent Document 3 discloses a technique of improving the cleaning property over a long period of use by containing organic resin particles containing a styrene structure in the surface layer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, according to the studies of the present inventors, in the technique disclosed in Patent Document 3, while a surface layer excellent in cleaning property and wear resistance can be obtained, when fluorine atom-containing resin particles are used, the residual potential may deteriorate.

[0005] Therefore, an object of the present invention is to provide an electrophotographic photoreceptor capable of reducing the residual potential while maintaining good cleaning property and wear resistance even in an electrophotographic photoreceptor containing no fluorine atoms.

Means for Solving the Problems

[0006] According to one aspect of the present disclosure, there is provided an electrophotographic photoreceptor having a surface layer, the surface layer contains vinyl resin particles and a charge transport material, the vinyl resin particles are surface-treated with a compound represented by the following formula (A) and / or (B), and the electrophotographic photoreceptor is characterized by this.

Chemical Formula

[0007] According to another aspect of the present disclosure, there is provided a process cartridge that integrally supports the electrophotographic photoreceptor and at least one means selected from the group consisting of a charging means, a developing means, and a cleaning means, and is detachable from the electrophotographic apparatus main body. According to another aspect of the present disclosure, there is provided an electrophotographic apparatus having the electrophotographic photoreceptor, a charging means, an image exposure means, a developing means, and a transfer means.

Effects of the Invention

[0008] According to one aspect of the present disclosure, it is possible to provide an electrophotographic photoreceptor that is excellent in cleaning property and durability and has a reduced residual potential.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0010] Hereinafter, the present invention will be described in detail with reference to preferred embodiments. As a result of investigations by the present inventors, by incorporating vinyl resin particles surface-treated with the following formula (A) and / or (B) in the surface layer of the electrophotographic photoreceptor, an electrophotographic photoreceptor excellent in wear resistance and cleaning property in the surface layer and having a suppressed residual potential was obtained.

Chemical formula

[0011] Regarding the reason why the electrophotographic photoreceptor of the present disclosure is excellent in abrasion resistance and cleaning property in the surface layer and excellent in the effect of suppressing residual potential, the present inventors have speculated as follows. An electrophotographic photoreceptor having a surface layer containing organic resin particles derived from a vinyl bond such as a styrene structure (hereinafter, also referred to as "resin particles having a vinyl bond") has high abrasion resistance and excellent cleaning property, but the residual potential increases due to repeated use. This is considered to be because the resin particles having a vinyl bond partially have a double bond terminal region caused by the termination reaction of polymer synthesis on the particle surface, and this has become a trap site causing the increase in residual potential.

[0012] As a result of the study by the present inventors, by treating the resin particles having a vinyl bond contained in the surface layer with a surface treatment agent represented by the above formula (A) and / or (B), the trap sites on the surface of the resin particles having a vinyl bond are reduced, and it has been found that an electrophotographic photoreceptor excellent in abrasion resistance, cleaning property, and the effect of suppressing residual potential can be obtained.

[0013] In particular, in the above formula (A), when at least one of R 11 ~R 14 is an alkyl group or a phenyl group, the adsorptivity to the surface of the vinyl resin particles is improved, and it is possible to avoid the surface treatment agent itself becoming a trap site, and it is considered that a sufficient residual potential suppressing effect can be obtained.

[0014] <Vinyl resin particles> The surface layer of the electrophotographic photoreceptor of the present invention contains vinyl resin particles surface-treated with the compound represented by the above formula (A) or (B). Examples of the resin contained in the vinyl resin particles used in the present invention include acrylic resins, styrene-acrylic resins, styrene resins, polyethylene resins, and the like. It is also preferable to use particles containing a plurality of the above resins. Among the above, from the viewpoint of sufficiently exerting the effects of the present invention, the vinyl resin particles according to the present invention are more preferably styrene-acrylic resins.

[0015] In the cross-sectional observation of the surface layer, the vinyl resin particles preferably have an arithmetic average of the major axis diameters of the primary particles (average primary particle diameter) measured from the secondary electron image by a scanning electron microscope in the range of 10 nm or more and 300 nm or less from the viewpoints of improving dispersibility and suppressing residual potential. The average primary particle diameter of the vinyl resin particles can be measured and calculated by the following method.

[0016] (Measurement method of average primary particle diameter) The average primary particle diameter of the vinyl resin particles is measured as follows using a field emission scanning electron microscope (FE-SEM). The vinyl resin particles are attached to a commercially available carbon conductive tape, and the vinyl resin particles not attached to the conductive tape are removed with compressed air, and platinum evaporation is performed. The vapor-deposited vinyl resin particles were observed using an FE-SEM (S-4700) manufactured by Hitachi High-Technologies Corporation. The measurement conditions of the FE-SEM are as follows. Acceleration voltage: 2 kV WD: 5 mm Magnification: 20,000 times Number of pixels: 1280 pixels vertically and 960 pixels horizontally (size per pixel: 5 nm) From the obtained image, the Feret diameters of 100 vinyl resin particles were determined using ImageJ (open-source software manufactured by the National Institutes of Health (NIH) of the United States), and the average value was calculated and used as the average primary particle diameter. The vinyl resin particles of the present disclosure may be used alone or in combination of two or more.

[0017] <Surface treatment agent> The vinyl resin particles used in the present invention are surface-treated with a compound represented by the following formula (A) or (B). From the viewpoint of residual potential, at least one of R 11 ~R 14 in the following formula (A) is particularly preferably composed of an alkyl group or a phenyl group. [Chemical formula]

[0018] In the elemental ratio of the surface layer, the content of silicon atoms derived from the compound used for surface treatment is preferably 0.0010 atomic% or more and 0.3000 atomic% or less with respect to all atoms in the surface layer. From the viewpoint of crack suppression, it is preferably 0.0010 atomic% or more with respect to all atoms in the surface layer excluding hydrogen atoms. Further, from the viewpoint of suppressing the residual potential, it is preferably 0.3000 atomic% or less with respect to all atoms in the surface layer excluding hydrogen atoms.

[0019] (Method for measuring silicon content) Elemental analysis of the surface layer is measured as follows using X-ray photoelectron spectroscopy (XPS). As the measurement sample, a surface layer piece cut out to a size of 10 mm square is set on the XPS dedicated platen. Then, using the following XPS apparatus, the X-ray irradiation location and the sputtering location by GCIB (gas cluster ion beam) irradiation are set in the above sample section. Apparatus used: PHI5000VersaProbeII manufactured by ULVAC-PHI, Inc. Irradiation ray: Al-Kα ray Beam diameter: 100 μ Output: 25 W 15 kV Photoelectron capture angle: 45° PassEnergy: 58.70 eV Stepsize: 0.125 eV XPS peaks: Si2p, N1s, C1s, O1s Measurement range: 300 μm × 200 μm Measurement of Si1 (atomic%) was performed under the above conditions. Furthermore, under the following sputtering conditions, sputtering was performed from the outermost surface of the surface layer to a position 40 nm deep, and the value measured under the above measurement conditions was taken as Si2 (atomic %). GUN type: GCIB (Gas Cluster Ion Beam) SputterSetting: 10 kV Regarding the position at a depth of 40 nm, the sputtering rate (rate of depth with respect to time) was measured in advance, the sputtering time corresponding to 40 nm was calculated, and sputtering was performed for the calculated time, so that sputtering was performed up to the position at a depth of 40 nm.

[0020] <Electrophotographic photoreceptor> FIG. 1 shows an example of the layer structure of the electrophotographic photoreceptor of the present disclosure. In FIG. 1, an undercoat layer 102, a charge generation layer 103, a charge transport layer 104, and a surface layer 105 are laminated on a support 101. The photosensitive layer may be composed of a laminated photosensitive layer having a charge generation layer and a charge transport layer, or may be composed of a single-layer photosensitive layer containing a charge generating substance and a charge transporting substance. In the present invention, the outermost layer of the electrophotographic photoreceptor is defined as the surface layer. As a method for manufacturing the electrophotographic photoreceptor of the present invention, a method of preparing coating liquids for each layer, sequentially coating the desired layers, and drying them can be mentioned. At this time, examples of the coating method of 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 preferable from the viewpoints of efficiency and productivity. Hereinafter, each layer will be described.

[0021] <Support> The support of the electrophotographic photoreceptor is preferably a conductive one (conductive support). Examples of the shape of the support include a cylindrical shape, a belt shape, and a sheet shape. Among these, a cylindrical support is preferable. Further, an electrochemical treatment such as anodic oxidation, a blasting treatment, a cutting treatment, or the like may be performed on the surface of the support. Examples of the material of the support include metals, resins, and glasses. Examples of the metal include aluminum, iron, nickel, copper, gold, stainless steel, and alloys thereof. Among these, an aluminum support made of aluminum is preferred. In addition, for resins and glass, it is preferable to impart conductivity by means such as mixing or coating with a conductive material.

[0022] <Conductive layer> A conductive layer may be provided on the support. By providing the conductive layer, it is possible to conceal scratches and unevenness on the surface of the support and to control light reflection on the support surface. The conductive layer preferably contains conductive particles and a binder resin. Examples of the material of the conductive particles include metal oxides, metals, carbon black, etc. Examples of the metal oxide include zinc oxide, aluminum oxide, indium oxide, silicon oxide, zirconium oxide, tin oxide, titanium oxide, strontium titanate, magnesium oxide, antimony oxide, bismuth oxide, etc. Examples of the metal include aluminum, nickel, iron, nichrome, copper, zinc, silver, etc. Among these, it is preferable to use metal oxide particles as the conductive particles, and more preferably titanium oxide particles, tin oxide particles, or zinc oxide particles. When using metal oxide particles as the conductive particles, the surface of the metal oxide particles may be treated with a silane coupling agent or the like, or the metal oxide particles may be doped with elements such as phosphorus or aluminum and their oxides. In addition, the conductive particles may have a laminated structure having core particles and a coating layer that coats the particles. Examples of the core particles include titanium oxide particles, barium sulfate particles, zinc oxide particles, etc. Examples of the coating layer include metal oxide particles such as tin oxide. When using metal oxide particles as the conductive particles, the volume average particle diameter thereof is preferably 1 nm or more and 500 nm or less, and more preferably 3 nm or more and 400 nm or less.

[0023] Examples of the binding resin include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, silicone resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, alkyd resin, etc. Further, the conductive layer may further contain a concealer such as silicone oil, resin particles, titanium oxide, etc. The conductive layer can be formed by preparing a coating liquid for the conductive layer containing each of the above materials and a solvent, forming this coating film on a support, and drying it. Examples of the solvent used in the coating liquid for the conductive layer include alcohol solvents, sulfoxide solvents, ketone solvents, ether solvents, ester solvents, aromatic hydrocarbon solvents, etc. Examples of the dispersion method for dispersing conductive particles in the coating liquid for the conductive layer include methods using a paint shaker, sand mill, ball mill, and liquid collision type high-speed disperser. The average film thickness of the conductive layer is preferably 1 μm or more and 50 μm or less, and particularly preferably 3 μm or more and 40 μm or less.

[0024] <Undercoat layer> In the present disclosure, an undercoat layer may be provided on the support or the conductive layer. By providing the undercoat layer, the interlayer adhesion function can be enhanced and a charge injection blocking function can be imparted. The undercoat layer preferably contains a binding resin. Further, the undercoat layer may be formed as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group. Examples of the binding resin include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, polyvinyl phenol resin, alkyd resin, polyvinyl alcohol resin, polyethylene oxide resin, polypropylene oxide resin, polyamide resin, polyamic acid resin, polyimide resin, polyamideimide resin, cellulose resin, etc. Examples of the polymerizable functional group of the monomer having a coincident functional group include an isocyanate group, a blocked isocyanate group, a methylol group, an alkylated methylol group, an epoxy group, a metal alkoxide group, a hydroxy group, an amino group, a carboxy group, a thiol group, a carboxylic anhydride group, a carbon-carbon double bond group, and the like.

[0025] Further, the undercoat layer may further contain an electron transport material, metal oxide particles, metal particles, a conductive polymer, etc. for the purpose of enhancing electrical characteristics. Among these, it is preferable to use an electron transport material and metal oxide particles. Examples of the electron transport material include a quinone compound, an imide compound, a benzimidazole compound, a cyclopentadienylidene compound, a fluorenone compound, a xanthone compound, a benzophenone compound, a cyanovinyl compound, a halogenated aryl compound, a silole compound, a boron-containing compound, and the like. As the electron transport material, an electron transport material having a polymerizable functional group may be used and copolymerized with the monomer having the above polymerizable functional group to form an undercoat layer as a cured film. Examples of the metal oxide particles include particles of indium tin oxide, tin oxide, indium oxide, titanium oxide, strontium titanate, zinc oxide, aluminum oxide, etc. Silicon dioxide particles can also be used. Examples of the metal particles include particles of gold, silver, aluminum, etc.

[0026] The metal oxide particles contained in the undercoat layer may be surface-treated using a surface treatment agent such as a silane coupling agent before use. As a method for surface-treating the metal oxide particles, a general method is used. For example, a dry method or a wet method can be mentioned. The dry method involves adding an aqueous alcohol solution, an organic solvent solution, or an aqueous solution containing a surface treatment agent while stirring metal oxide particles in a mixer capable of high-speed stirring such as a Henschel mixer, uniformly dispersing them, and then drying. In the wet method, metal oxide particles and a surface treatment agent are stirred in a solvent or dispersed using a sand mill or the like with glass beads or the like, and after dispersion, the solvent is removed by filtration or distillation under reduced pressure. After removing the solvent, it is preferable to perform baking at 100°C or higher.

[0027] The undercoat layer may further contain an additive. For example, it can contain known materials such as metal particles such as aluminum particles, conductive substance particles such as carbon black, charge transport substances, metal chelate compounds, and organometallic compounds. The undercoat layer can be formed by preparing a coating solution for the undercoat layer containing each of the above materials and a solvent, forming this coating film on a support or a conductive layer, and drying and / or curing it. Examples of the solvent used in the coating solution for the undercoat layer include organic solvents such as alcohol, sulfoxide, ketone, ether, ester, aliphatic halogenated hydrocarbon, and aromatic compound. In the present disclosure, it is preferable to use alcohol-based and ketone-based solvents. Examples of the dispersion method for preparing the coating solution for the undercoat layer include methods using a homogenizer, ultrasonic disperser, ball mill, sand mill, roll mill, vibration mill, attritor, and liquid collision type high-speed disperser. The average film thickness of the undercoat layer is preferably 0.1 μm or more and 50 μm or less, more preferably 0.2 μm or more and 40 μm or less, and particularly preferably 0.3 μm or more and 30 μm or less.

[0028] <Photosensitive layer> The photosensitive layer of the electrophotographic photoreceptor is mainly classified into (1) a laminated photosensitive layer and (2) a single-layer photosensitive layer. (1) The laminated photosensitive layer is a photosensitive layer having a charge generation layer containing a charge generating substance and a charge transport layer containing a charge transport substance. (2) The single-layer photosensitive layer is a photosensitive layer containing both a charge generating substance and a charge transport substance.

[0029] (1) Laminated photosensitive layer The laminated photosensitive layer has a charge generation layer and a charge transport layer.

[0030] (1-1) Charge generation layer The charge generation layer preferably contains a charge generating material and a binder resin. Examples of the charge generating material include azo pigments, perylene pigments, polycyclic quinone pigments, indigo pigments, phthalocyanine pigments, etc. Among these, azo pigments and phthalocyanine pigments are preferred. Among the phthalocyanine pigments, oxy titanium phthalocyanine pigment, chloro gallium phthalocyanine pigment, and hydroxy gallium phthalocyanine pigment are preferred. The content of the charge generating material in the charge generation 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 generation layer. Examples of the binder resin 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.

[0031] In addition, the charge generation layer may further contain additives such as antioxidants and ultraviolet absorbers. Specifically, hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, etc. can be mentioned. The charge generation layer can be formed by preparing a coating solution for the charge generation layer containing the above-mentioned respective materials and a solvent, forming this coating film on the undercoat layer, and drying it. Examples of the solvent used in the coating solution include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, aromatic hydrocarbon-based solvents, etc. The average film 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.

[0032] (1-2) Charge transport layer The charge transport layer preferably contains a charge transport material and a binder material. When the protective layer described later is not provided, the charge transport layer becomes the surface layer of the electrophotographic photoreceptor. In this case, the charge transport layer contains vinyl resin particles surface-treated with a compound represented by the above formula (A) and / or (B), a binder resin, and a charge transport material. Examples of the charge transport material include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, triarylamine compounds, and resins having groups derived from these substances. Among these, it preferably has the structure of the following formula (C).

Chemical formula

[0033] The content of the charge transport material 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. Examples of the binder resin include polycarbonate resins, polyarylate resins, acrylic resins, polystyrene resins, etc. Among these, thermoplastic resins are preferred, and particularly, polycarbonate resins and polyarylate resins are preferred. The content ratio (mass ratio) of the charge transport material to the resin is preferably 4:10 to 20:10, more preferably 5:10 to 12:10. The content of the surface-treated vinyl resin particles in the charge transport layer is preferably 1% by mass or more and 30% by mass or less.

[0034] In addition, the charge transport layer may contain additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, and lubricants. Specifically, examples include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, polystyrene resin particles, polyethylene resin particles, boron nitride particles, and fluororesin particles. The charge transport layer can be formed by preparing a coating solution for the charge transport layer containing each of the above materials and a solvent, forming this coating film on the charge generation layer, and drying it. Examples of the solvent used in the coating solution include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Among these solvents, ether-based solvents or aromatic hydrocarbon-based solvents are preferred. The average film thickness of the charge transport layer is preferably 5 μm or more and 50 μm or less, and particularly preferably 35 μm or more and 50 μm or less.

[0035] (2) Single-layer photosensitive layer The single-layer photosensitive layer can be formed by preparing a coating solution for the photosensitive layer containing a charge generating substance, a charge transporting substance, a resin, and a solvent, forming this coating film on the undercoat layer, and drying it. Examples of the charge generating substance, charge transporting substance, and resin are the same as those exemplified in the above “(1) Laminated photosensitive layer”. The average film thickness of the single-layer photosensitive layer is preferably 5 μm or more and 50 μm or less, and particularly preferably 35 μm or more and 50 μm or less.

[0036] <Protective layer> In the present disclosure, a protective layer may be provided on the photosensitive layer. By providing the protective layer, the durability can be improved. When providing the protective layer, the protective layer becomes the surface layer of the electrophotographic photoreceptor. In this case, the protective layer contains surface-treated vinyl resin particles and a binder material.

[0037] The protective layer may be formed as a cured film by polymerizing a composition containing, for example, a monomer having a polymerizable functional group, which is a raw material of the binder material. Examples of the reaction at that time include thermal polymerization reaction, photopolymerization reaction, radiation polymerization reaction, and the like. Examples of the polymerizable functional group of the monomer having a polymerizable functional group include, for example, isocyanate group, blocked isocyanate group, methylol group, alkylmethylol group, epoxy group, metal alkoxyl group, hydroxy group, amino group, carboxy group, thiol group, carboxylic anhydride group, and a group containing a carbon-carbon double bond. Examples of the group containing a carbon-carbon double bond include acryloyl group, methacryloyl group, and the like. As the monomer having a polymerizable functional group, a monomer having a charge transport ability may be used. Here, the cured product of the monomer having a polymerizable functional group is the binder material of the protective layer. That is, in the present disclosure, the surface layer contains at least one selected from the binder material, or the binder material and the raw material of the binder material. As the monomer having a polymerizable functional group, it is preferable to use a charge transporting compound having a chain polymerizable functional group. The charge transporting compound having a chain polymerizable functional group preferably has the structure of the following formula (D). The surface layer according to the present invention is preferably a polymer containing the compound represented by the following formula (D) from the viewpoints of durability and cleanability.

Chemical formula

[0038] The content of the surface-treated vinyl resin particles in the surface layer (protective layer) is preferably 1% by mass or more and 30% by mass or less based on the total mass of the entire surface layer (protective layer). The protective layer may contain additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, etc. Specifically, hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, etc. can be mentioned. The protective layer can be formed by preparing a coating solution for the protective layer containing each of the above materials and a solvent, forming this coating film on the photosensitive layer, and drying and / or curing it. Examples of the solvent used in the coating solution include alcohol solvents, ketone solvents, ether solvents, sulfoxide solvents, ester solvents, and aromatic hydrocarbon solvents. The film thickness of the protective layer is preferably 0.50 μm or more and 10 μm or less, and more preferably 1 μm or more and 7 μm or less.

[0039] <Surface treatment of the electrophotographic photoreceptor> In the present disclosure, surface treatment of the electrophotographic photoreceptor may be performed. By performing surface treatment, the behavior of the cleaning means (cleaning blade) in contact with the electrophotographic photoreceptor can be made more stable. Examples of the surface treatment method include a method of pressing a mold having convex portions against the surface of the electrophotographic photoreceptor to perform shape transfer, a method of imparting an uneven shape by mechanical polishing, or a method of causing powder to collide with the surface of the electrophotographic photoreceptor to roughen the surface. Thus, by providing concave portions or convex portions in the surface layer of the electrophotographic photoreceptor, the behavior of the cleaning means in contact with the electrophotographic photoreceptor can be made more stable. The above concave portions or convex portions may be formed over the entire surface of the electrophotographic photoreceptor, or may be formed on a part of the surface of the electrophotographic photoreceptor. When the concave portions or convex portions are formed on a part of the surface of the electrophotographic photoreceptor, it is preferable that the concave portions or convex portions are formed over the entire contact area with at least the cleaning means (cleaning blade). When forming the concave portions, the concave portions can be formed on the surface of the electrophotographic photoreceptor by pressing a mold having convex portions corresponding to the concave portions against the surface of the electrophotographic photoreceptor and performing shape transfer.

[0040] <Abrasive Tool for Mechanical Polishing> Known means can be used for mechanical polishing. Generally, an abrasive tool is brought into contact with an electrophotographic photoreceptor, and either one or both of them are relatively moved to polish the surface of the electrophotographic photoreceptor. The abrasive tool is an abrasive member provided with a layer in which abrasive grains are dispersed in a binder resin on a base material. Examples of the abrasive grains include particles such as aluminum oxide, chromium oxide, diamond, iron oxide, cerium oxide, corundum, silica, silicon nitride, boron nitride, molybdenum carbide, silicon carbide, tungsten carbide, titanium carbide, and silicon oxide. The particle size of the abrasive grains is preferably 0.01 μm or more and 50 μm or less, and more preferably 1 μm or more and 15 μm or less. If the particle size of the abrasive grains is too small, the polishing force becomes weak, and it becomes difficult to increase the molar fraction ratio of fluorine atom F to carbon atom C, that is, the F / C ratio, by X-ray photoelectron spectroscopy of the surface layer on the outermost surface of the electrophotographic photoreceptor. These abrasive grains can be used alone or in combination of two or more. When mixing two or more types, they may be different or the same in terms of material and particle size. As the binder resin for dispersing the abrasive grains used in the abrasive tool, known thermoplastic resins, thermosetting resins, reactive resins, electron beam curable resins, ultraviolet curable resins, visible light curable resins, and antifungal resins can be used. Examples of the thermoplastic resin include vinyl chloride resin, polyamide resin, polyester resin, polycarbonate resin, amino resin, styrene-butadiene copolymer, urethane elastomer, and polyamide-silicone resin. Examples of the thermosetting resin include phenol resin, phenoxy resin, epoxy resin, polyurethane resin, polyester resin, silicone resin, melamine resin, and alkyd resin. Also, an isocyanate-based curing agent may be added to the thermoplastic resin. The film thickness of the layer formed by dispersing the abrasive grains in the binder resin of the abrasive tool is preferably 1 μm or more and 100 μm or less. If the film thickness is too thick, film thickness unevenness is likely to occur, and as a result, unevenness in the surface roughness of the object to be polished becomes a problem. On the other hand, if the film thickness is too thin, the abrasive grains are likely to fall off. The shape of the base material of the abrasive tool is not particularly limited. In the examples of the present disclosure, a sheet-shaped base material was used to efficiently polish a cylindrical electrophotographic photoreceptor, but other shapes may also be used (hereinafter, the abrasive tool of the present disclosure is also referred to as a "polishing sheet"). The material of the base material of the abrasive tool is not particularly limited either. For example, as the material of the sheet-shaped base material, paper, woven fabric, non-woven fabric, and plastic film can be mentioned. The abrasive tool can be obtained by applying and drying a paint in which the above abrasive grains, binder resin, and a solvent capable of dissolving the binder resin are mixed and dispersed on the base material.

[0041] <Polishing device> An example of the polishing device for the electrophotographic photoreceptor of the present disclosure is shown in FIG. 2. FIG. 2 is a device for polishing a cylindrical electrophotographic photoreceptor using a polishing sheet. In FIG. 2, the polishing sheet 2-1 is wound around a hollow shaft 2-6, and a motor (not shown) is arranged so as to apply tension to the polishing sheet 2-1 in the direction opposite to the direction in which the polishing sheet 2-1 is fed to the shaft 2-6. The polishing sheet 2-1 is fed in the direction of the arrow, passes through the backup roller 2-3 via the guide rollers 2-2a and 2-2b, and the polished polishing sheet 2-1 is wound around the winding means 2-5 by a motor (not shown) via the guide rollers 2-2c and 2-2d. The polishing is performed by constantly pressing the polishing sheet 2-1 against the object to be processed (the electrophotographic photoreceptor before polishing) 2-4. Since the polishing sheet 2-1 is often insulating, it is preferable to use a material grounded to the ground or having conductivity at the portion in contact with the polishing sheet 2-1. The feed speed of the polishing sheet 2-1 is preferably in the range of 10 to 1000 mm / min. If the feed amount is small, adhesion of the binder resin to the surface of the polishing sheet 2-1 may cause deep scratches on the surface of the object to be processed 2-4. The object to be processed 2-4 is placed at a position facing the backup roller 2-3 via the polishing sheet 2-1. From the viewpoint of improving the uniformity of the surface roughness of the object to be processed 2-4, the backup roller 2-3 is preferably made of an elastic body. At this time, the object to be processed 2-4 and the backup roller 2-3 are pressed against each other via the polishing sheet 2-1 at a desired set value for a predetermined time, and the surface of the object to be processed 2-4 is polished. The rotation direction of the object to be processed 2-4 may be the same as or opposite to the direction in which the polishing sheet 2-1 is fed. Also, the rotation direction may be changed during polishing. The pressing pressure of the backup roller 2-3 against the object to be processed 2-4 depends on the hardness of the backup roller 2-3 and the polishing time, but is preferably 0.005 to 15 N / m 2 is preferred. The surface roughness of the electrophotographic photoreceptor can be adjusted by appropriately selecting the feed speed of the polishing sheet 2-1, the pressing pressure of the backup roller 2-3, the abrasive grain type of the polishing sheet, the film thickness of the binder resin of the polishing sheet, the thickness of the base material, etc.

[0042] <Measurement of the maximum height Rmax in JIS B0601 1982> The surface roughness of the electrophotographic photoreceptor can be measured by known means. For example, the following can be mentioned. Surface roughness meters such as the Surf Coater SE3500 type surface roughness measuring instrument manufactured by Kosaka Laboratory Ltd., the non-contact three-dimensional surface measuring machine Micromap 557N manufactured by Hishikawa System Co., Ltd., and microscopes capable of acquiring three-dimensional shapes such as the ultra-depth shape measuring microscope VK-8550 and VK-9000 manufactured by Keyence Corporation. From the viewpoint of cleanability, in the surface roughness obtained by these means, it is preferable that the maximum height Rmax is 2 μm or less.

[0043] <Process cartridge, electrophotographic apparatus> The electrophotographic photoreceptor of the present disclosure may be one of the components of a process cartridge or an electrophotographic apparatus. The process cartridge integrally supports the electrophotographic photoreceptor described so far and at least one means selected from the group consisting of a charging means, a developing means, a transfer means, and a cleaning means, and is detachable from the electrophotographic apparatus main body. Further, the electrophotographic apparatus is characterized by having the electrophotographic photoreceptor, a charging means, an exposure means, a developing means, and a transfer means described so far.

[0044] FIG. 3 shows an example of a schematic configuration of an electrophotographic apparatus having a process cartridge including an electrophotographic photoreceptor. The cylindrical (drum-shaped) electrophotographic photoreceptor 1 is rotationally driven about the axis 2 in the direction of the arrow at a predetermined peripheral speed (process speed). The surface of the electrophotographic photoreceptor 1 is charged to a predetermined positive or negative potential by the charging means 3 during the rotation process. In FIG. 3, a roller charging method using a roller-type charging member is shown, but charging methods such as a corona charging method, a proximity charging method, and an injection charging method may also be employed. The surface of the charged electrophotographic photoreceptor 1 is irradiated with exposure light 4 from an exposure means (not shown), and an electrostatic latent image corresponding to the target image information is formed. The exposure light 4 is light whose intensity is modulated corresponding to the time-series electrical digital image signal of the target image information, and is output from an image exposure means such as slit exposure or laser beam scanning exposure, for example. The electrostatic latent image formed on the surface of the electrophotographic photoreceptor 1 is developed (normal development or reversal development) with toner accommodated 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 to the transfer material 7 by the transfer means 6. At this time, a bias voltage having a polarity opposite to the charge held by the toner is applied to the transfer means 6 from a bias power source (not shown). Further, when the transfer material 7 is paper, the transfer material 7 is taken out from a paper feeding unit (not shown) and fed between the electrophotographic photoreceptor 1 and the transfer means 6 in synchronization with the rotation of the electrophotographic photoreceptor 1. The transfer material 7 onto which the toner image has been transferred from the electrophotographic photoreceptor 1 is separated from the surface of the electrophotographic photoreceptor 1 and conveyed to the fixing means 8, and is printed out of the electrophotographic apparatus as an image formation (print, copy) by receiving the fixing process of the toner image. The electrophotographic apparatus may have a cleaning means 9 for removing deposits such as toner remaining on the surface of the electrophotographic photoreceptor 1 after transfer. Further, instead of providing a separate cleaning means, a so-called cleanerless system in which the above deposits are removed by a developing means or the like may be used. In the present disclosure, among the components selected from the above electrophotographic photoreceptor 1, charging means 3, developing means 5, cleaning means 9, etc., a plurality of components can be housed in a container and integrally supported to form a process cartridge. Further, it can be configured to be detachable from the electrophotographic apparatus main body. For example, it can be configured as follows.At least one selected from the charging means 3, the developing means 5, and the cleaning means 9 is integrally supported together with the electrophotographic photoreceptor 1 and made into a cartridge. By using guiding means 12 such as rails of the electrophotographic apparatus main body, it can be made into a process cartridge 11 that is detachable from the electrophotographic apparatus main body. The electrophotographic apparatus may have a discharging mechanism that discharges the surface of the electrophotographic photoreceptor 1 by pre-exposure light 10 from a pre-exposure means (not shown). Further, guiding means 12 such as rails may be provided to attach and detach the process cartridge 11 of the present disclosure to and from the electrophotographic apparatus main body. The electrophotographic apparatus of the present disclosure is characterized by having the electrophotographic photoreceptor 1 and at least one means selected from the group consisting of the charging means 3, the exposure means, the developing means 5, and the transfer means 6.

[0045] The electrophotographic photoreceptor of the present disclosure can be used in a laser beam printer, an LED printer, a copying machine, a facsimile machine, and a multi-functional machine thereof.

Example

[0046] Hereinafter, the present invention will be described in more detail using examples and comparative examples, but it is not limited thereto. In the description of the following examples, "parts" means based on mass unless otherwise specified.

[0047] <Surface treatment of vinyl resin particles> Vinyl resin particles surface-treated by the following methods were obtained using the compounds represented by the above formula (A) or (B), respectively.

[0048] (Particle 1) 5 parts of styrene-acrylic resin particles with an average primary particle size of 150 nm, 15 parts of pure water, 15 parts of hexane, and 10 parts of methanol were added to a glass flask equipped with a stirrer, a constant temperature bath, and a thermometer. After heating to 50°C with stirring, 1 part of dimethoxydiphenylsilane was added, and the mixture was stirred for 4 hours while maintaining the temperature at 50°C. Then, the mixture was centrifuged, and the separated precipitate was washed with ethanol and dried under reduced pressure at a temperature of 50°C and a pressure of 1000 Pa or less for 4 hours to obtain Particle 1, which is surface-treated vinyl resin particles.

[0049] (Particles 2 - 10) In the treatment of Particle 1, except for changing the particle type, surface treatment agent, and surface treatment time shown in Table 1, Particles 2 - 10 were obtained in the same manner as Particle 1.

[0050]

Table 1

[0051] <Fabrication of Electrophotographic Photoconductor> 〔Example 1 - 1〕 (Support 1) As the support (conductive support), a cylindrical aluminum cylinder (JIS - A3003, aluminum alloy, outer diameter 30.6 mm, length 370 mm, wall thickness 1 mm) that had been machined by cutting was used. Ultrasonic cleaning was performed in a cleaning solution containing a detergent (trade name: Chemicol CT, manufactured by Tokiwa Chemical Co., Ltd.) in pure water. After subsequently rinsing off the cleaning solution, ultrasonic cleaning was further performed in pure water for degreasing treatment, and this was designated as Support 1.

[0052] (Undercoat Layer 1) Zinc oxide particles (specific surface area: 19 m 2 / g, powder resistance: 4.7×10 6100 parts of Ω·cm were stirred and mixed with 500 parts of toluene, and 0.8 part of a silane coupling agent (compound name: N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, trade name: KBM602, manufactured by Shin-Etsu Chemical Co., Ltd.) was added thereto, followed by stirring for 6 hours. Thereafter, toluene was distilled off under reduced pressure, and the mixture was dried by heating at 130 °C for 6 hours to obtain surface-treated zinc oxide particles A. Subsequently, 15 parts of butyral (trade name: BM-1, manufactured by Sekisui Chemical Co., Ltd.) as a polyol and 15 parts of blocked isocyanate (trade name: Duranate TPA-B80E, non-volatile content 80% by mass, manufactured by Asahi Kasei Chemicals Corporation) were dissolved in a mixed solvent of 73.5 parts of methyl ethyl ketone and 73.5 parts of 1-butanol. To this solution, 80.8 parts of the surface-treated zinc oxide particles A and 0.81 part of 2,3,4-trihydroxybenzophenone (manufactured by Tokyo Chemical Industry Co., Ltd.) were added, and the mixture was dispersed for 3 hours in an atmosphere at 23 ± 3 °C using a sand mill apparatus with glass beads having a diameter of 0.8 mm. After the dispersion treatment, 0.01 part of silicone oil (trade name: SH28PA, manufactured by Toray Dow Corning Co., Ltd. (former: Toray Dow Corning Silicone Co., Ltd.)) and 5.6 parts of crosslinked polymethyl methacrylate (PMMA) particles (trade name: Tech Polymer SSX-103, manufactured by Sekisui Chemical Products Co., Ltd., average primary particle diameter: 3 μm) were added and stirred to prepare a coating liquid for the undercoat layer. The obtained coating liquid for the undercoat layer was dip-coated onto the above-mentioned support 1 to form a coating film, and the coating film was dried at 160 °C for 30 minutes to form an undercoat layer 1 having a film thickness of 18 μm.

[0053] (Charge generation layer 1) 4 parts of crystalline hydroxygallium phthalocyanine crystals (charge generating substance) 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 the compound represented by the following formula (1) were added to a solution prepared by dissolving 2 parts of polyvinyl butyral (trade name: Esrec BX-1, manufactured by Sekisui Chemical Co., Ltd.) in 100 parts of cyclohexanone. Then, dispersion treatment was carried out for 1 hour in an atmosphere of 23 ± 3°C using a sand mill with glass beads having a diameter of 1 mm. After the dispersion treatment, 100 parts of ethyl acetate was added to prepare a coating solution for the charge generation layer. This coating solution for the charge generation layer was dip-coated on the undercoat layer 1, and the obtained coating film was dried at 90°C for 10 minutes to form a charge generation layer 1 having a film thickness of 0.15 μm.

Chemical formula

[0054] (Charge transport layer 1) 60 parts of the compound represented by the following formula (2), 30 parts of the compound represented by the following formula (3), 10 parts of the compound represented by the following formula (4), 100 parts of bisphenol Z type polycarbonate resin (trade name: Iupilon Z400, manufactured by Mitsubishi Engineering Plastics Corporation), and 0.2 part of polycarbonate having a structural unit represented by the following formula (5) (viscosity average molecular weight Mv: 20,000) were dissolved in a mixed solvent of 272 parts of o-xylene, 256 parts of methyl benzoate, and 272 parts of dimethoxymethane to prepare a coating solution for the charge transport layer. This coating solution for the charge transport layer was dip-coated on the above charge generation layer 1 to form a coating film, and the obtained coating film was dried at 115°C for 50 minutes to form a charge transport layer 1 having a film thickness of 18 μm.

Chemical formula

Chemical formula

Chemical formula

Chemical formula

[0055] (Protective layer 1) 40 parts of the previously prepared particles 1 were added to 100 parts of 1-propanol. Then, it was passed through a high-pressure disperser (trade name: Microfluidizer M-110EH, manufactured by Microfluidics Corporation, USA) to obtain a dispersion of particles 1. To the obtained dispersion of particles 1, 97.3 parts of a charge transport compound represented by the following formula (6) and 100 parts of 1-propanol were added. Then, filtration was performed using a polytetrafluoroethylene filter (trade name: PF-040, manufactured by Advantec Toyo Co., Ltd.) to prepare a dispersion of particles 1 (coating solution for the protective layer). [Chemical formula] This coating solution for the protective layer was dip-coated on the charge transport layer to form a coating film, and the obtained coating film was dried at 40°C for 5 minutes. After drying, in a nitrogen atmosphere, 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 absorption dose of 15 kGy. Then, in a nitrogen atmosphere, heat treatment was performed for 15 seconds under the condition that the temperature of the coating film reached 135°C. The oxygen concentration from the irradiation of the electron beam to the heat treatment for 15 seconds was 15 ppm. Next, in the air, it was naturally cooled until the temperature of the coating film reached 25°C, and then heat treatment was performed for 1 hour under the condition that the coating film reached 105°C to form a surface layer (protective layer 1) with a film thickness of 5 μm. According to the above-described method for measuring the silicon content, the silicon content was 0.1%. In this way, an electrophotographic photoreceptor having a support and a surface layer before surface polishing was produced.

[0056] (Surface processing of the electrophotographic photoreceptor) (Polishing of the electrophotographic photoreceptor before surface polishing) The surface of the electrophotographic photoreceptor before forming the surface shape was polished. The polishing was performed using the polishing apparatus shown in FIG. 2 under the following conditions. Feed speed of the polishing sheet; 400 mm / min Rotation speed of the electrophotographic photoreceptor; 450 rpm Pushing-in of the electrophotographic photoreceptor to the backup roller; 3.5 mm Rotation direction of the polishing sheet and the electrophotographic photoreceptor; With Backup roller; Outer diameter 100 mm, Asker C hardness 25 The polishing sheet A to be mounted on the polishing device was prepared by mixing the polishing abrasive grains used for GC3000 and GC2000 manufactured by Riken Korundum Co., Ltd. GC3000 (Polishing sheet surface roughness Ra 0.83 μm) GC2000 (Polishing sheet surface roughness Ra 1.45 μm) Polishing sheet A (Polishing sheet surface roughness Ra 1.12 μm) The polishing time using the polishing sheet A was set to 20 seconds.

[0057] (Measurement of polishing depth L (μm)) Regarding the electrophotographic photoreceptor after polishing, the maximum height Rmax conforming to JIS B 0601 1982 was measured using a surface roughness measuring instrument Surfcoader SE3500 type manufactured by Kosaka Laboratory Ltd. The measurement conditions were set as follows. The measurement was carried out arbitrarily at three locations in a 5 mm square range of the electrophotographic photoreceptor after polishing, and the average value was adopted as the polishing depth L (μm). The polishing depth L of the electrophotographic photoreceptor after surface polishing was 0.75 μm. Also, in Examples 1-2 to 1-12 described later, the polishing depth L of the electrophotographic photoreceptor subjected to surface processing was all 0.75 μm. (Measurement conditions) Detector: R2μm Stylus: Diamond needle of 0.7 mN Filter: 2CR Cutoff value: 0.08 mm Measurement length: 2.5 mm Feed speed: 0.1 mm

[0058] [Examples 1-2 to 1-12, Comparative Examples 1-1 to 1-3] In the formation of the protective layer 1, an electrophotographic photoreceptor was produced in the same manner as in Example 1-1, except that the particles and the mass parts of the particle additives shown in Table 1 were changed. The content of silicon atoms in the film in the surface layer is shown in accordance with Table 2.

[0059]

Table 2

[0060] 〔Example 2-1〕 (Support 2) As the support (conductive support), a cylindrical aluminum cylinder (JIS-A3003, aluminum alloy, outer diameter 30 mm, length 357.5 mm, wall thickness 0.7 mm) that had been machined by cutting was used. Ultrasonic cleaning was performed in a cleaning solution containing a detergent (trade name: Chemicol CT, manufactured by Tokiwa Chemical Co., Ltd.) in pure water. Subsequently, after flushing away the cleaning solution, ultrasonic cleaning was further performed in pure water for degreasing treatment, and this was designated as Support 2.

[0061] (Undercoat layer 2) 60 parts of zinc oxide particles (average particle diameter: 70 nm, specific surface area value: 15 m 2 / g) were stirred and mixed with 500 parts of tetrahydrofuran. To this, 0.75 part of a silane coupling agent (compound name: N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, trade name: KBM603, manufactured by Shin-Etsu Chemical Co., Ltd.) was added, and stirring was carried out for 2 hours. Thereafter, tetrahydrofuran was distilled off under reduced pressure, and heating and drying were performed at 120 °C for 3 hours to obtain surface-treated zinc oxide particles. Subsequently, 25 parts of butyral (trade name: BM-1, manufactured by Sekisui Chemical Co., Ltd.) and 22.5 parts of blocked isocyanate (trade name: Sumidur BL-3173, manufactured by Sumitomo Bayer Urethane Co., Ltd.) as polyols were dissolved in 142 parts of methyl ethyl ketone. To this solution, 100 parts of the surface-treated zinc oxide particles and 1 part of alizarin were added, and this was dispersed using a sand mill with glass beads having a diameter of 1 mm for 5 hours. After the dispersion treatment, 0.008 part of dioctyltin dilaurate and 6.5 parts of silicone resin particles (Tospearl 145, manufactured by GE Toshiba Silicones Co., Ltd.) were added and stirred to prepare a coating solution for the undercoat layer. The obtained coating solution for the undercoat layer was dip-coated on the above-mentioned support 2 to form a coating film, and the coating film was dried at 190 °C for 24 minutes to form an undercoat layer 2 with a film thickness of 15 μm.

[0062] (Charge generation layer 2) Next, 15 parts of chlorogallium phthalocyanine crystals having strong diffraction peaks at at least 7.4 °, 16.6 °, 25.5 °, and 28.3 ° of the Bragg angle (2θ ± 0.2 °) with respect to CuKα characteristic X-rays, 10 parts of vinyl chloride-vinyl acetate copolymer resin (VMCH, manufactured by Nippon Union Carbide Corporation), and 300 parts of n-butyl alcohol were mixed, and dispersed for 4 hours using a sand mill with glass beads having a diameter of 1 mm to prepare a coating solution for the charge generation layer. This coating solution for the charge generation layer was dip-coated on the above-mentioned undercoat layer 2, and the obtained coating film was dried at 150 °C for 5 minutes to form a charge generation layer 2 with a film thickness of 0.2 μm.

[0063] (Charge transport layer 2) Next, 10 parts of the above-mentioned surface-treated particles 1 and 50 parts of tetrahydrofuran were stirred and mixed at a liquid temperature of 20 °C for 48 hours to obtain a preparation liquid A. Next, 40 parts of N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzidine, 10 parts of the compound represented by the following formula (7), 75 parts of bisphenol Z-type polycarbonate resin (viscosity average molecular weight 40,000), and 2.0 parts of 2,6-di-t-butyl-4-methylphenol as an antioxidant were mixed, and 250 parts of tetrahydrofuran was mixed and dissolved to obtain a preparation liquid B. After adding the preparation liquid A to this preparation liquid B and stirring and mixing, it was passed through a high-pressure disperser (trade name: Microfluidizer M-110EH, manufactured by Microfluidics Corporation, USA) to obtain a dispersion liquid. Thereafter, filtration was performed using a polytetrafluoroethylene filter (trade name: PF-040, manufactured by Advantec Toyo Co., Ltd.) to prepare a coating solution for the charge transport layer. This coating solution for the charge transport layer was dip-coated on the above-mentioned charge generation layer to form a coating film, and the obtained coating film was dried at 150 °C for 40 minutes to form a charge transport layer with a film thickness of 40 μm. In this way, an electrophotographic photoreceptor was fabricated. [Chemical formula]

[0064] [Examples 2-2 to 2-12, Comparative Examples 2-1 to 2-3] In the formation of the charge transport layer 2, an electrophotographic photoreceptor was fabricated in the same manner as in Example 2-1, except that the particles and the mass parts of the particle addition shown in Table 3 were changed. The content of silicon atoms in the film in the surface layer is shown in Table 3.

[0065] [Table 3]

[0066] [Evaluation of the electrophotographic photoreceptor] The evaluation of the electrophotographic photoreceptors fabricated from the electrophotographic photoreceptors obtained in Examples 1-1 to 1-12, 2-1 to 2-12, Comparative Examples 1-1 to 1-3, and 2-1 to 2-3 was carried out as follows.

[0067] [Evaluation apparatus 1-1] The electrophotographic photoreceptors fabricated in Examples 1-1 to 1-12 and Comparative Examples 1-1 to 1-3 were mounted on an imagePRESS C800 (trade name), a copying machine manufactured by Canon Inc., for evaluation. Specifically, the above evaluation apparatus was installed in a normal temperature and humidity environment of 23°C and 50% RH relative humidity. The fabricated electrophotographic photoreceptor was mounted on the process cartridge for magenta, and then mounted on the station of the magenta process cartridge for evaluation.

[0068] [Evaluation apparatus 1-2] The electrophotographic photoreceptors prepared in Examples 1-1 to 1-12 and Comparative Examples 1-1 to 1-3 were mounted on a modified model of imagePRESS C800 (trade name), a copier manufactured by Canon Inc., for evaluation. The charging means of the modified model is a charging means that applies a voltage obtained by superimposing an AC voltage on a DC voltage to a roller-type contact charging member (charging roller), and the exposure means is an exposure means of a laser image exposure method (wavelength 680 nm). Specifically, the evaluation apparatus was installed in a normal temperature and humidity environment of 23°C and 50% RH. The prepared electrophotographic photoreceptor was mounted on a process cartridge for magenta, and then mounted on the station of the magenta process cartridge for evaluation. The charging conditions were adjusted such that the charging potential was -800 V and the exposure potential was -300 V, as well as the exposure amount of the exposure means. The surface potential of the electrophotographic photoreceptor was measured by removing the developing cartridge from the evaluation apparatus and inserting a potential measuring device therein. The potential measuring device is configured by arranging a potential measuring probe (trade name: model6000B-8, manufactured by Trek Japan Co., Ltd.) at the developing position of the developing cartridge. The position of the potential measuring probe with respect to the electrophotographic photoreceptor was at the center in the bus bar direction of the electrophotographic photoreceptor, with a gap of 3 mm from the surface of the electrophotographic photoreceptor. Furthermore, the potential at the central portion of the electrophotographic photoreceptor was measured using a surface electrometer (trade name: model344, manufactured by Trek Japan Co., Ltd.).

[0069] 〔Evaluation Apparatus 2-1〕 The electrophotographic photoreceptors prepared in Examples 2-1 to 2-12 and Comparative Examples 2-1 to 2-3 were mounted on a modified model of imageRUNNER iR-ADV C3835F (trade name), a copier manufactured by Canon Inc., for evaluation. Specifically, the evaluation apparatus was installed in a normal temperature and humidity environment of 23°C and 50% RH. The prepared electrophotographic photoreceptor was mounted on a process cartridge for cyan, and then mounted on the station of the cyan process cartridge for evaluation.

[0070] 〔Evaluation Apparatus 2-2〕 The electrophotographic photoreceptors prepared in Examples 2-1 to 2-12 and Comparative Examples 2-1 to 2-3 were mounted on a modified model of a copier imageRUNNER iR-ADV C3835F (trade name) manufactured by Canon Inc. for evaluation. Specifically, the above evaluation apparatus was installed in a normal temperature and humidity environment of 23°C and 50% RH. The prepared electrophotographic photoreceptor was mounted on the process cartridge for cyan, and then mounted on the station of the cyan process cartridge for evaluation. The charging conditions were adjusted such that the charging potential was -700 V and the exposure potential was -200 V, and the exposure amount of the exposure means was adjusted accordingly. The surface potential of the electrophotographic photoreceptor was measured by removing the developing cartridge from the above evaluation apparatus and inserting a potential measuring device therein. The potential measuring device was configured by arranging a potential measuring probe (trade name: model6000B-8, manufactured by Trek Japan Co., Ltd.) at the developing position of the developing cartridge. The position of the potential measuring probe with respect to the electrophotographic photoreceptor was at the center in the bus bar direction of the electrophotographic photoreceptor, and the gap from the surface of the electrophotographic photoreceptor was 3 mm. Furthermore, the potential at the central portion of the electrophotographic photoreceptor was measured using a surface potentiometer (trade name: model344, manufactured by Trek Japan Co., Ltd.).

[0071] (Evaluation of wear amount) The evaluation of the wear amount was carried out using the above Evaluation Apparatus 1-1 and Evaluation Apparatus 2-1. The total film thickness of the initial electrophotographic photoreceptor was measured at 5 points at equal intervals in the bus bar direction of the electrophotographic photoreceptor using an eddy current thickness gauge (Fischerscope, manufactured by Fischer Instruments), and the average value of the 5 points was taken as the value of the film thickness before durability. Subsequently, continuous durability testing was carried out for 50,000 sheets using an A4-sized test chart with an image ratio of 5%. The film thickness of the electrophotographic photoreceptor after durability was measured in the same manner as the initial film thickness, and the difference in film thickness before and after the durability test was taken as the wear amount (μm). The smaller the wear amount, the better the abrasion resistance and cleaning performance. The results are shown in Tables 4 and 5.

[0072] (Residual potential evaluation) The evaluation of the residual potential was performed by measuring the residual potential using the above-described evaluation apparatus 1-2 and evaluation apparatus 2-2. The applied bias was set so that the dark potential of the non-exposed portion of the electrophotographic photoreceptor was -600 V, and the light quantity of the laser beam was set to 0.313 μJ / cm 2 After repeating the exposure equivalent to A3 size five times, the potential of the first round immediately after pre-exposure and discharging was measured and taken as the residual potential. In Example 1-1, the residual potential was 10 V. The smaller the value of the residual potential, the better the result. In this way, the evaluation results are shown in Tables 4 and 5.

[0073]

Table 4

[0074]

Table 5

[0075] The disclosure of this embodiment includes the following configurations. [Configuration 1] An electrophotographic photoreceptor having a surface layer, wherein the surface layer contains vinyl resin particles and a charge transport material, and the vinyl resin particles are surface-treated with a compound represented by the following formula (A) and / or (B), an electrophotographic photoreceptor characterized by this.

Chemical formula

Chemical formula

Chemical formula

Explanation of Signs

[0076] 101 Substrate 102 Undercoat layer 103 Charge generation layer 104 Charge transport layer 105 Surface layer 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

Claims

Claim 1 An electrophotographic photoreceptor having a surface layer, wherein the surface layer contains vinyl resin particles and a charge transport material, and the vinyl resin particles are surface-treated with a compound represented by the following formula (A) and / or (B). The electrophotographic photoreceptor is characterized by this. 【Chemical 1】 (In formula (A), R 11 ~R 14 each independently represents an alkyl group, a phenyl group, an alkoxy group or a halogen atom.) However, R 11 ~R 14 At least one of them is an alkoxy group or a halogen atom. Also, R 11 to R 14 at least one of which is an alkyl group or a phenyl group. In formula (B), R 21 ~R 26 each independently represents an alkyl group or a phenyl group.) Claim 2 R in the formula (A) above 11 ~R 14 wherein two of them are phenyl groups, the electrophotographic photoreceptor according to claim 1. Claim 3 The electrophotographic photoreceptor according to claim 1, wherein the vinyl resin particles are styrene acrylic resin. Claim 4 The electrophotographic photoreceptor according to claim 1, wherein the content of the vinyl resin particles in the surface layer is 1% by mass or more and 30% by mass or less based on the total mass of the surface layer. Claim 5 The electrophotographic photoreceptor according to claim 1, wherein the content of silicon atoms derived from the compound represented by the formula (A) in the surface layer is 0.0010 atomic% or more and 0.3000 atomic% or less based on all atoms in the surface layer. Claim 6 The electrophotographic photoreceptor according to claim 1, wherein the charge transport material contains a compound represented by the following formula (C). 【Chemical 2】 (In formula (C), R １ and R ２ are each independently a hydrogen atom or a methyl group, and R ３ is a linear or branched alkyl group having 1 to 5 carbon atoms, a methacryloyloxy group, or an acryloyloxy group.) Claim 7 The electrophotographic photoreceptor according to claim 1, wherein the surface layer is a polymer of a composition containing a compound represented by the following formula (D). 【Chemical Formula 3】 (In formula (D), R 4 and R ５ are each independently a hydrogen atom or a methyl group, and R 6 is a methacryloyloxy group or an acryloyloxy group.) Claim 8 A process cartridge, characterized in that it integrally supports the electrophotographic photoreceptor according to any one of claims 1 to 7 and at least one means selected from the group consisting of a charging means, a developing means, and a cleaning means, and is detachable from the main body of the electrophotographic apparatus. Claim 9 An electrophotographic apparatus, characterized by having the electrophotographic photoreceptor according to any one of claims 1 to 7, as well as a charging means, an image exposure means, a developing means, and a transfer means.

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