JP5655288B2 - Oxide film, electrophotographic photosensitive member, process cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to an oxide material, an electrophotographic photosensitive member, a process cartridge, and an image forming apparatus.

  In recent years, the electrophotographic method has greatly expanded as a copier and printer technology. In the electrophotographic method, an electrophotographic photoreceptor (referred to as “photoreceptor” as appropriate) is used.

For example, Patent Document 1 proposes an electrophotographic photosensitive member having a surface layer mainly composed of magnesium fluoride.
Patent Document 2 proposes an electrophotographic photosensitive member having a surface protective layer made of amorphous silicon carbide by a catalytic CVD method on an organic photosensitive layer.

Patent Document 3 proposes an electrophotographic photoreceptor having a surface layer containing a small amount of gallium atoms in amorphous carbon.
Patent Document 4 proposes a method of forming a hard amorphous carbon nitride film useful for an electrophotographic photosensitive member.

Patent Document 5 proposes a non-single-crystal hydrogenated nitride semiconductor used for a charge generation layer or the like of an electrophotographic photosensitive member.
Patent Document 6 proposes an electrophotographic photoreceptor including a surface layer containing oxygen and a group 13 element and having an oxygen content on the outermost surface exceeding 15 atomic%.

JP 2003-29437 A JP 2003-316053 A JP-A-2-110470 JP 2003-27238 A Japanese Patent Laid-Open No. 11-186571 JP 2006-267507 A

  An object of the present invention is to provide an oxide material having both wear resistance and light transmittance as compared with an oxide material in which gallium, zinc, and oxygen do not satisfy the following atomic composition ratio.

In order to achieve the above object, the following invention is provided.
The invention of claim 1 includes at least gallium, zinc, and oxygen, and an atomic ratio of the zinc to the gallium (number of zinc atoms / number of gallium atoms) is 0.01 or more and 0.6 or less. And the ratio of the number of oxygen atoms to the sum of the number of atoms of gallium and zinc [number of oxygen atoms / (number of gallium atoms + number of zinc atoms)] is 1.0 or more and 1.6 or less. The oxide film includes an oxide material and has conductivity of 1 × 10 ⁵ Ωcm to 1 × 10 ¹³ Ωcm .
The invention according to claim 2 is the oxide film according to claim 1, wherein the oxide material is amorphous.
According to a third aspect of the present invention, the zinc is 0.4 atomic percent or more and 25 atomic percent or less with respect to the sum of the numbers of atoms of the gallium, the zinc, and the oxygen contained in the oxide material. It is an oxide film as described in above.
A fourth aspect of the present invention is an electrophotographic photosensitive member having the oxide film layer according to any one of the first to third aspects.
An invention according to claim 5 is an electrophotographic photoreceptor comprising an inorganic photosensitive layer and the oxide film layer according to any one of claims 1 to 3 disposed on the inorganic photosensitive layer. is there.
The invention according to claim 6 is an electrophotographic photoreceptor comprising an organic photosensitive layer and the oxide film layer according to any one of claims 1 to 3 disposed on the organic photosensitive layer. is there.
A seventh aspect of the present invention is a process cartridge comprising the electrophotographic photosensitive member according to any one of the fourth to sixth aspects.
According to an eighth aspect of the present invention, there is provided an electrophotographic photosensitive member according to any one of the fourth to sixth aspects, a charging unit for charging the electrophotographic photosensitive member, and a latent image on the surface of the charged electrophotographic photosensitive member. Forming a latent image formed on the surface of the electrophotographic photosensitive member, developing means for developing the latent image with a developer containing toner to form a toner image, and forming on the surface of the electrophotographic photosensitive member A transfer unit that transfers the toner image to a recording medium.

According to the first aspect of the invention, compared to the case where the atomic composition ratio of gallium, zinc, and oxygen contained in the oxide material does not satisfy the atomic composition ratio of the first aspect, both wear resistance and light transmittance are compatible. An oxide film is provided.
According to the second aspect of the present invention, an oxide film having high chemical stability is provided as compared with the case where the oxide material is polycrystalline.
According to the invention of claim 3, an oxide film having high chemical stability is provided as compared with the case where the content of zinc contained in the oxide material does not satisfy the ratio of claim 3.
The invention according to claim 4 provides an electrophotographic photosensitive member having high chemical stability as compared with the case where the oxide film layer according to claim 1 is not provided.
According to the invention of claim 5, there is provided an electrophotographic photoreceptor having high chemical stability as compared with the case where the oxide film according to claim 1 is not provided on the inorganic photosensitive layer using silicon or the like. Provided.
According to the invention of claim 6, there is provided an electrophotographic photosensitive member that has both wear resistance and light transmittance as compared with the case where the oxide film layer according to claim 1 is not provided on the organic photosensitive layer. Provided.
According to the seventh aspect of the present invention, there is provided a process cartridge in which image blur is suppressed as compared with the case where the electrophotographic photosensitive member having the oxide film layer according to the first aspect is not provided.
According to the eighth aspect of the present invention, there is provided an image forming apparatus in which image blur is suppressed as compared with the case where the electrophotographic photosensitive member having the oxide film layer according to the first aspect is not provided.

It is the schematic which shows an example of the layer structure of the electrophotographic photoreceptor which concerns on this embodiment. It is the schematic which shows the other example of the layer structure of the electrophotographic photoreceptor which concerns on this embodiment. It is the schematic which shows the other example of the layer structure of the electrophotographic photoreceptor which concerns on this embodiment. It is the schematic which shows an example of a structure of the film-forming apparatus used for formation of the oxide material which concerns on this embodiment. It is the schematic which shows the cross section of A1-A2 of the film-forming apparatus shown to FIG. 4A. It is the schematic which shows the other example of the plasma generator used for formation of the oxide material which concerns on this embodiment. FIG. 2 is a schematic diagram illustrating an example of a configuration of a process cartridge including an electrophotographic photosensitive member according to the present embodiment. 1 is a schematic diagram illustrating an example of a configuration of an image forming apparatus including an electrophotographic photosensitive member according to an exemplary embodiment.

  Hereinafter, embodiments will be described with reference to the accompanying drawings as appropriate. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and repeated description is omitted as appropriate.

  When the surface of the electrophotographic photosensitive member is, for example, hard amorphous silicon, image blur and image flow often occur due to adhesion of discharge products or the like particularly at high humidity. For this reason, carbon-based films are often used as surface layers. However, a carbon-based film such as a hydrogenated amorphous carbon film (aC: H) or a fluorinated film such as aC: H, F becomes a colored film when the hardness is satisfied. As the surface wears, light transmission increases and sensitivity increases. In addition, when wear occurs unevenly, the sensitivity also becomes uneven, and an influence appears as image unevenness particularly in a halftone.

  Further, a hydrogenated amorphous silicon carbide film (a-SiC: H) may be used for an electrophotographic photosensitive member as satisfying transparency and hardness. Blur and image flow are likely to occur.

  The same applies to the surface layer of an organic electrophotographic photosensitive member having an organic photosensitive layer as a material other than an electrophotographic photosensitive member made of a silicon-based hard material. Since the relationship between hardness and the amount of wear also leads to the difficulty of adhesion and removal of discharge products, as a material constituting the surface layer, it has durability, little alteration, and deposits are difficult to adhere, and Materials that are easy to remove are desirable.

  For example, as a hard surface layer formed by coating, when using a polymer compound having a siloxane bond as the surface layer, although the wear resistance is improved, the hardness is low and scratches and wear are reduced. Adhesion at the time increases, and the life of the photoreceptor is shortened by the adhesion of the toner component.

On the other hand, for carbon-based thin film materials, diamond-like carbon and diamond films are used for applications that take advantage of various characteristics such as wear resistant materials, low friction materials, gas barrier materials, and electron emission materials in addition to semiconductor materials. R & D is widely conducted.
In order to obtain a film having sufficient hardness, it is necessary to increase the diamond-type sp3 bondability. However, since mixing of sp2 bonds of graphite is inevitable, the film is colored black and a transparent film cannot be obtained. An attempt to obtain a transparent film results in an organic soft film.
In recent years, research and development of carbon nitride films have been carried out, but the hardness and characteristics of diamond films and diamond-like carbon films have not been reached.
In order to obtain a hard and dense film, for example, a high temperature treatment of 1000 ° C. and a large amount of discharge power are required, so that application to a polymer film or the like is limited.

The inventors of the present invention have conducted research on group 13 oxide semiconductor materials and the like in order to achieve the hardening and transparency of the surface layer of the electrophotographic photosensitive member. If it is an oxide material having a ratio, both wear resistance and light transmittance are compatible. By using this oxide material to form the surface layer of an electrophotographic photosensitive member, image degradation due to high humidity and discharge products Has been found to be suppressed. Furthermore, the present inventors have found that this oxide material has not only the surface layer of the electrophotographic photoreceptor, but also an undercoat layer, a charge transport layer, or a high hardness and light transmittance, and, for example, 1 × 10 It has been found that the present invention is also useful as a material constituting other electronic devices that require electrical conductivity of ⁵ Ωcm or more and 1 × 10 ¹³ Ωcm or less.

<Oxide material>
The oxide material according to this embodiment includes at least gallium, zinc, and oxygen, and the ratio of the number of zinc atoms to the number of gallium atoms (the number of zinc atoms / the number of gallium atoms) is 0.01 or more and 0.0. 6 or less, and the ratio of the number of oxygen atoms to the sum of the number of atoms of gallium and zinc [number of oxygen atoms / (number of gallium atoms + number of zinc atoms)] is 1.0 or more and 1.6 or less (Hereinafter, an oxide material containing gallium, zinc, and oxygen and having the above composition ratio is abbreviated as “GaZnO material” as appropriate).

In general, an oxide material containing gallium, zinc, and oxygen is more likely to be colored and have lower light transmittance as the zinc content is higher. Also, the surface energy for water is higher and the chemical stability is lower. On the other hand, too little zinc content leads to high resistance. Further, gallium has high stability with respect to water, but if it is too much with respect to oxygen, the light transmission becomes low.
On the other hand, the GaZnO material according to the present embodiment has the above-described atomic composition ratio, so that both wear resistance and light transmittance are compatible, and chemical stability is also high. For example, 1 × 10 ⁵ Conductivity of Ωcm or more and 1 × 10 ¹³ Ωcm or less. The application of the GaZnO material of the present embodiment is not particularly limited as long as it is a member that requires the above characteristics, but is particularly useful as a surface layer of an electrophotographic photoreceptor, for example.

<Electrophotographic photoreceptor>
1, 2, and 3 schematically show examples of the layer configuration of an electrophotographic photoreceptor in which the GaZnO material according to this embodiment is used.
In the electrophotographic photoreceptor shown in FIG. 1, a charge generation layer 2, a charge transport layer 3, and a surface layer 4 are sequentially disposed on a conductive support 1 from the support 1 side. The electrophotographic photoreceptor shown in FIG. 2 has an undercoat layer (charge injection blocking layer) 5, a charge generation layer 2, a charge transport layer 3, an intermediate layer 6, and a surface layer on the conductive support 1 from the support 1 side. 4 are arranged sequentially. In the electrophotographic photosensitive member shown in FIG. 3, an undercoat layer 5, a photosensitive layer 7 in which a charge transport layer and a charge generation layer are integrated, and a surface layer 4 are sequentially formed on a conductive support 1 from the support 1 side. Has been placed.

The oxide material according to the present embodiment is applied to a layer other than the charge generation layer 2 in the electrophotographic photosensitive member having these configurations. Hereinafter, a case where the oxide material is applied to a surface layer will be described as a representative example.
The charge generation layer 2, the charge transport layer 3, and the photosensitive layer 7 in which the charge generation layer and the charge transport layer are integrated may be composed of an organic polymer or an inorganic material. Or may be composed of an organic polymer and an inorganic material.
The organic polymer compound that forms the charge generation layer 2 and the charge transport layer 3 may be thermoplastic, thermosetting, or formed by reacting a plurality of types of materials.
In the case of the organic polymer layer, an intermediate layer may be provided between the surface polymer layer 4 and the surface layer 4 from the viewpoint of improvement in hardness, expansion coefficient, and adhesion. The intermediate layer preferably has intermediate physical properties between the surface layer 4 and the charge transport layer. The intermediate layer may function as a layer for trapping charges.

  In any configuration, the surface layer 4 formed of the GaZnO material according to the present embodiment has high transparency, is dense, and has high hardness. Therefore, the generation of scratches on the surface of the photoreceptor is suppressed by having this surface layer. Is done. In addition, because of its excellent surface chemical stability and low surface energy, adsorption of nitrogen oxides is unlikely to occur, and because it is an oxide with a high oxygen concentration, it can be used against oxidizing atmospheres such as ozone and nitrogen oxides. Shows tolerance.

The surface layer 4 according to the present embodiment may trap surface charges on the surface of the layer or trap them inside. Further, a surface charge may be positively injected. When the charge is injected into the surface layer 4, it is necessary to trap the charge at the interface with the photosensitive layer. When the electron is injected into the surface layer with negative charge, the surface of the hole transport layer is charged. A trap function may be achieved, or a layer for blocking charge injection and trapping may be provided. The same applies to the case of positive charging.
Hereinafter, each component will be described more specifically.

-Conductive support-
The conductive support 1 supports a photosensitive layer formed on the surface. In the present specification, “conductive” of the conductive support refers to a property of having a volume resistivity of less than 10 ¹³ Ω · cm.
Examples of the conductive support 1 include aluminum, copper, iron, stainless steel, zinc, nickel and other metal drums; aluminum, copper, gold, silver, platinum, palladium, titanium on a substrate such as a sheet, paper, plastic, and glass. , Nickel-chromium, stainless steel, copper-indium or the like deposited on metal; conductive metal compound such as indium oxide or tin oxide deposited on the substrate; metal foil laminated on the substrate; Carbon black, indium oxide, tin oxide-antimony oxide powder, metal powder, copper iodide and the like are dispersed in a binder resin and applied to the substrate to conduct a conductive treatment.

The shape of the support 1 is preferably a cylindrical shape. When a metal pipe is used as the conductive support 1, the surface of the support 1 may be a raw pipe, but the surface of the support may be roughened by surface treatment in advance. . Due to such roughening, when a coherent light source such as a laser beam is used as the exposure light source, grain-like density unevenness due to interference light that can be generated inside the photosensitive member is suppressed. Examples of the surface treatment method include mirror cutting, etching, anodizing, rough cutting, centerless grinding, sand blasting, wet honing and the like.
In particular, it is desirable to use as the conductive support 1 a material obtained by subjecting the surface of an aluminum support to an anodizing treatment in terms of improving adhesion to the photosensitive layer and improving film formability.

-Undercoat layer-
The material constituting the undercoat layer 5 is acetal resin such as polyvinyl butyral; polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl In addition to polymer resins such as acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, melamine resin, zirconium, titanium, aluminum, manganese, silicon atom, etc. An organometallic compound containing
These compounds are used alone or as a mixture or polycondensate of a plurality of compounds. Among these, an organometallic compound containing zirconium or silicon is desirably used because it has a low residual potential, a small potential change due to the environment, and a small potential change due to repeated use. In addition, the organometallic compound may be used alone or in combination of two or more, or may be used in combination with the above-described binder resin.

  As organosilane compounds (organometallic compounds containing silicon atoms), vinyltrimethoxysilane, vinyltris (2-methoxyethoxysilane), γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxy) Ethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N, N- Bis (β-hydro Shiechiru)-.gamma.-aminopropyltriethoxysilane, etc. γ- chloropropyl trimethoxysilane. Among these, vinyltriethoxysilane, vinyltris (2-methoxyethoxysilane), γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxy Silane, N-β- (aminoethyl) γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyl Silane coupling agents such as trimethoxysilane, γ-mercaptopropyltrimethoxysilane, and γ-chloropropyltrimethoxysilane are desirably used.

  In addition to the above, a known undercoat layer such as the undercoat layer described in paragraphs 0113 to 0136 of JP-A-2008-075520 may be used.

-Charge generation layer-
The charge generation layer 2 is formed by depositing a charge generation material by a vacuum deposition method or by applying a solution containing an organic solvent and a binder resin.

Examples of charge generation materials include amorphous selenium, crystalline selenium, selenium-tellurium alloy, selenium-arsenic alloy, and other selenium compounds; inorganic photoconductors such as selenium alloy, zinc oxide, and titanium oxide; Sensitized, various phthalocyanine compounds such as metal-free phthalocyanine, titanyl phthalocyanine, copper phthalocyanine, tin phthalocyanine, and gallium phthalocyanine; Various organic pigments such as salts; or dyes are used.
In addition, these organic pigments generally have several types of crystals. In particular, phthalocyanine compounds have various crystal types including α type and β type. Any of these crystal forms may be used as long as it is a pigment capable of obtaining characteristics.

  Of the charge generation materials described above, phthalocyanine compounds are desirable. In this case, when the photosensitive layer is irradiated with light, the phthalocyanine compound contained in the photosensitive layer absorbs photons and generates carriers. At this time, since the phthalocyanine compound has high quantum efficiency, the absorbed photons are efficiently absorbed to generate carriers.

Further, among the phthalocyanine compounds, phthalocyanines shown in the following (1) to (3) are more preferable.
(1) At least 7.6 °, 10.0 °, 25.2 °, 28.0 ° in the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum using Cukα rays as the charge generation material Crystalline hydroxygallium phthalocyanine having a diffraction peak at the position.
(2) At least 7.3 °, 16.5 °, 25.4 °, 28.1 ° in the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum using Cukα rays as the charge generation material Crystalline chlorogallium phthalocyanine having a diffraction peak at the position.
(3) Diffraction peaks at positions of at least 9.5 °, 24.2 °, and 27.3 ° in the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum using Cukα rays as the charge generation material. A crystalline form of titanyl phthalocyanine.

  Since these phthalocyanine compounds have not only high photosensitivity, but also high photosensitivity, photoconductors having a photosensitive layer containing these phthalocyanine compounds are required to have high-speed image formation and repeatability. It is desirable as a photoreceptor of a color image forming apparatus.

  Note that the peak intensity and position may slightly deviate from these values depending on the crystal shape and measurement method. However, if the X-ray diffraction patterns are basically the same, the same crystal type is assumed. To be judged.

Examples of the binder resin used for the charge generation layer 2 include the following.
Namely, polycarbonate resin such as bisphenol A type or bisphenol Z type and its copolymer, polyarylate resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer Resin, vinylidene chloride-acrylonitrile copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N-vinylcarbazole, etc. .

  These binder resins may be used alone or in combination of two or more. The mixing ratio of the charge generation material and the binder resin (charge generation material: binder resin) is preferably in the range of 10: 1 to 1:10 in terms of mass ratio. The thickness of the charge generation layer 2 is generally preferably in the range of 0.01 μm to 5 μm, and more preferably in the range of 0.05 μm to 2.0 μm.

The charge generation layer 2 may contain at least one electron accepting substance for the purpose of improving sensitivity, reducing residual potential, reducing fatigue during repeated use, and the like. Examples of the electron accepting material used for the charge generation layer 2 include succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrabromophthalic anhydride, tetracyanoethylene, tetracyanoquinodimethane, o-di Examples thereof include nitrobenzene, m-dinitrobenzene, chloranil, dinitroanthraquinone, trinitrofluorenone, peak phosphoric acid, o-nitrobenzoic acid, p-nitrobenzoic acid, and phthalic acid. Of these, fluorenone-based, quinone-based, and benzene derivatives having an electron-withdrawing substituent such as Cl, CN, NO ₂ are particularly preferable.

As a method for dispersing the charge generating material in the resin, methods such as a roll mill, a ball mill, a vibrating ball mill, an attritor, a dyno mill, a sand mill, and a colloid mill are used.
Known organic solvents as coating solution solvents for forming the charge generation layer 2, for example, aromatic hydrocarbon solvents such as toluene and chlorobenzene, methanol, ethanol, n-propanol, iso-propanol, n-butanol, etc. Aliphatic alcohol solvents, ketone solvents such as acetone, cyclohexanone and 2-butanone, halogenated aliphatic hydrocarbon solvents such as methylene chloride, chloroform and ethylene chloride, cyclic or straight chain such as tetrahydrofuran, dioxane, ethylene glycol and diethyl ether Examples include chain ether solvents, ester solvents such as methyl acetate, ethyl acetate, and n-butyl acetate.

  These solvents are used alone or in combination of two or more. When two or more kinds of solvents are mixed and used, for example, a solvent that dissolves the binder resin is used as the mixed solvent. However, when the photosensitive layer has a layer structure in which the charge transport layer and the charge generation layer are formed in this order from the conductive support side, charge generation is performed using a coating method that easily dissolves the lower layer, such as dip coating. When forming the layer, it is desirable to use a solvent that does not dissolve the lower layer such as the charge transport layer. In addition, when the charge generation layer is formed by using a spray coating method or a ring coating method with a relatively low erosion property of the lower layer, the selection range of the solvent is widened.

-Charge transport layer-
Examples of the charge transport material used for the charge transport layer 3 include the following. That is, oxadiazole derivatives such as 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole, 1,3,5-triphenyl-pyrazoline, 1- [pyridyl- (2)]- Pyrazoline derivatives such as 3- (p-diethylaminostyryl) -5- (p-diethylaminostyryl) pyrazoline, triphenylamine, tri (p-methyl) phenylamine, N, N-bis (3,4-dimethylphenyl) biphenyl Aromatic tertiary amino compounds such as -4-amine, dibenzylaniline, 9,9-dimethyl-N, N-di (p-tolyl) fluorenon-2-amine, N, N′-diphenyl-N, N Aromatic tertiary diamino compounds such as' -bis (3-methylphenyl)-[1,1-biphenyl] -4,4'-diamine, 3- (4'-dimethylamino) 1,2,4-triazine derivatives such as phenyl) -5,6-di- (4′-methoxyphenyl) -1,2,4-triazine, 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone, 4-diphenyl Aminobenzaldehyde-1,1-diphenylhydrazone, [p- (diethylamino) phenyl] (1-naphthyl) phenylhydrazone, 1-pyrenediphenylhydrazone, 9-ethyl-3-[(2methyl-1-indolinylimino) methyl Carbazole, 4- (2-methyl-1-indolinyliminomethyl) triphenylamine, 9-methyl-3-carbazole diphenylhydrazone, 1,1-di- (4,4′-methoxyphenyl) acrylaldehyde diphenylhydrazone , Β, β-bis (methoxyphenyl) vinyldiphenyl Hydrazone derivatives such as drazone, quinazoline derivatives such as 2-phenyl-4-styryl-quinazoline, benzofuran derivatives such as 6-hydroxy-2,3-di (p-methoxyphenyl) -benzofuran, p- (2,2-diphenyl) Hole transport materials such as α-stilbene derivatives such as vinyl) -N, N-diphenylaniline, enamine derivatives, carbazole derivatives such as N-ethylcarbazole, poly-N-vinylcarbazole and derivatives thereof are used. Or the polymer etc. which have the group containing the said compound in a principal chain or a side chain are mentioned. These charge transport materials are used alone or in combination of two or more.

The binder resin used for the charge transport layer 3 is not particularly limited, but the binder resin is preferably compatible with the charge transport material and has an appropriate strength.
Examples of this binder resin include various polycarbonate resins including bisphenol A, bisphenol Z, bisphenol C, bisphenol TP and the like, copolymers thereof, polyarylate resins and copolymers thereof, polyester resins, methacrylic resins, acrylic resins, Polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride copolymer resin, silicone Resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-acrylic copolymer resin, ethylene-alkyd resin, poly-N-vinylcarbazole resin, polyvinyl butyral resin, polyphenylene ether resin, etc. And the like. These resins are used alone or as a mixture of two or more.

  The molecular weight of the binder resin used for the charge transport layer 3 is selected depending on the layer thickness of the photosensitive layer and film forming conditions such as a solvent, but it is usually desirable that the viscosity average molecular weight is within the range of 3000 to 300,000. A range of 10,000 to 200,000 is more desirable.

The charge transport layer 3 is formed by applying and drying a solution in which the charge transport material and the binder resin are dissolved in an appropriate solvent. Examples of the solvent used for forming the coating solution for forming the charge transport layer include aromatic hydrocarbons such as benzene, toluene and chlorobenzene, ketones such as acetone and 2-butanone, methylene chloride, chloroform and ethylene chloride. And halogenated aliphatic hydrocarbons, cyclic or linear ethers such as tetrahydrofuran, dioxane, ethylene glycol and diethyl ether, or a mixed solvent thereof.
The blending ratio between the charge transport material and the binder resin is preferably within the range of 10: 1 to 1: 5.
The layer thickness of the charge transport layer is generally preferably in the range of 5 μm to 50 μm, and more preferably in the range of 10 μm to 40 μm.

The charge transport layer 3 and / or the charge generation layer 2 is used for the purpose of preventing deterioration of the photoreceptor due to ozone, oxidizing gas, or light or heat generated in the image forming apparatus, an antioxidant, a light stabilizer, a heat Additives such as stabilizers may be included.
Examples of the antioxidant include hindered phenols, hindered amines, paraphenylenediamines, arylalkanes, hydroquinones, spirochromans, spiroidanones or their derivatives, organic sulfur compounds, and organic phosphorus compounds.

The charge transport layer 3 is formed, for example, by applying a solution obtained by dissolving the charge transport material and the binder resin described above in an appropriate solvent and drying the solution. Examples of the solvent used for preparing the coating solution for forming the charge transport layer include aromatic hydrocarbons such as benzene, toluene and chlorobenzene, ketones such as acetone and 2-butanone, and halogens such as methylene chloride, chloroform and ethylene chloride. Or aliphatic ethers, cyclic or linear ethers such as tetrahydrofuran, dioxane, ethylene glycol and diethyl ether, or a mixed solvent thereof.
Silicone oil may be added to the charge transport layer forming coating solution as a leveling agent for improving the smoothness of the coating film to be coated and formed.

The compounding ratio of the charge transport material and the binder resin is desirably 10: 1 to 1: 5 by mass ratio.
The layer thickness of the charge transport layer 3 is generally preferably in the range of 5 μm to 50 μm, and more preferably in the range of 10 μm to 30 μm.

  The coating solution for forming the charge transport layer can be applied by dip coating, ring coating, spray coating, bead coating, blade coating, roller coating, knife coating, curtain coating, depending on the shape and application of the photoreceptor. This is performed using a coating method such as a coating method. As for drying, it is desirable to heat-dry after touch drying at room temperature (for example, 20 ° C. or higher and 30 ° C. or lower). The heat drying is desirably performed in a temperature range of 30 ° C. or more and 200 ° C. or less for a time in the range of 5 minutes to 2 hours.

  As the charge transport layer 3, for example, a known charge transport layer such as the charge transport layer described in paragraphs 0137 to 0150 of JP-A-2008-075620 may be used.

-Surface layer-
The surface layer 4 includes gallium, zinc, and oxygen, the atomic ratio of zinc to the number of gallium atoms (number of zinc atoms / number of gallium atoms) is 0.01 or more and 0.6 or less, and The ratio of the number of oxygen atoms to the sum of the number of atoms of gallium and zinc [number of oxygen atoms / (number of gallium atoms + number of zinc atoms)] is 1.0 or more and 1.6 or less. Yes. An oxide material having such a composition ratio has high hardness and light transmittance, a volume resistivity of 10 ⁵ Ωcm or more and 10 ¹³ Ωcm or less, low hydrophilicity, and excellent chemical stability. Layer.
The ratio of the number of zinc atoms to the number of gallium atoms (the number of zinc atoms / the number of gallium atoms) is preferably from 0.01 to 0.5 in terms of chemical stability and light transmittance.
Further, the ratio of the number of oxygen atoms to the sum of the number of atoms of gallium and zinc [number of oxygen atoms / (number of gallium atoms + number of zinc atoms)] is 1 from the viewpoint of chemical stability and light transmittance. .1 to 1.5 is desirable.

In the present embodiment, the composition of the GaZnO material and the atomic ratio, including the distribution in the layer thickness direction, are determined by, for example, Rutherford backscattering (RBS).
RBS uses, for example, NEC 3SDH Pelletron as an accelerator, CE & A RBS-400 as an end station, and 3S-R10 as a system. For analysis, the CE & A HYPRA program or the like is used.
The RBS measurement conditions are: He ++ ion beam energy is 2.275 eV, detection angle is 160 °, and Grazing Angle is 109 ° with respect to the incident beam.

Specifically, the RBS measurement is performed as follows.
First, a He ++ ion beam is incident on the sample perpendicularly, a detector is set at 160 ° with respect to the ion beam, and the backscattered He signal is measured. The composition ratio and the film thickness are determined from the detected energy and intensity of He. In order to improve the accuracy of obtaining the composition ratio and the film thickness, the spectrum may be measured at two detection angles. Accuracy is improved by measuring and cross-checking at two detection angles with different depth resolution and backscattering dynamics.
The number of He atoms back-scattered by the target atom is determined by three factors: 1) the atomic number of the target atom, 2) the energy of the He atom before scattering, and 3) the scattering angle.
The density is assumed from the measured composition by calculation, and this is used to calculate the layer thickness. The density error is within 20%.

  The content of each element in the entire surface layer is measured by, for example, secondary electron mass spectrometry or XPS (X-ray photoelectron spectroscopy).

Zinc may be distributed substantially uniformly or non-uniformly in the thickness direction of the surface layer 4. For example, the zinc concentration may be low on the outermost surface side, and may be composed of oxygen and gallium near the outermost surface, and a group 13 element (Al, In, etc.) other than gallium. Alternatively, the zinc concentration may be increased on the outermost surface side.
In addition, from the viewpoint of suppression of light transmission deterioration, suppression of high resistance, suppression of hydrophilicity, etc., the ratio of zinc is 0.4 atomic% or more with respect to the sum of the number of atoms of gallium, zinc, and oxygen. It is preferably 25 atomic% or less, and particularly preferably 0.4 atomic% or more and 20 atomic% or less.

  The film made of the GaZnO material according to this embodiment (referred to as “GaZnO film” as appropriate) may be a non-single-crystal material such as microcrystal, polycrystal, and amorphous. Among these, an amorphous film is particularly desirable in terms of surface smoothness, and a microcrystalline film is desirable in terms of hardness.

  The GaZnO film contains one or more elements selected from Si, Ge, and Sn for conductivity type control, that is, n-type, and Be, Mg, Ca for p-type. And one or more elements selected from Sr.

Further, the GaZnO film may contain hydrogen or further halogen atoms. From the viewpoint of improving the chemical stability of the film, the hydrogen content is desirably 5 atomic percent or more and 25 percent or less with respect to the sum of the numbers of atoms of gallium, zinc, oxygen, and hydrogen.
In the case of microcrystal, polycrystal, or amorphous, there are more bond defects, dislocation defects, crystal grain boundary defects, and the like than single crystals, and hence defects such as bond defects due to hydrogen or halogen atoms in the GaZnO film are not possible. It is effective for activation. That is, hydrogen and halogen atoms are taken into bond defects in the crystal and defects at the crystal grain boundaries to perform electrical compensation. For this reason, there are no traps related to the generation of photocarriers, the diffusion and movement of carriers, the reaction active sites are eliminated, and the surface layer becomes more stable.
In addition, about content of hydrogen, it calculates | requires by measuring an absolute value by hydrogen forward scattering (HFS). You may estimate by an infrared absorption spectrum.
HFS uses NEC 3SDH Pelletron as an accelerator, CE & A RBS-400 as an end station, and CE & A 3S-R10 as a system.
The analysis uses the CE & A HYPRA program.

The measurement conditions of HFS are as follows.
He ++ ion beam energy: 2.275 eV
A detection angle of 160 ° is Grazing Angle 30 ° with respect to the incident beam.

The HFS measurement picks up the hydrogen signal scattered in front of the sample by setting the detector at 30 ° to the He ++ ion beam and the sample at 75 ° from the normal. At this time, the detector is preferably covered with aluminum foil to remove He atoms scattered together with hydrogen. The quantification is performed by comparing the hydrogen counts of the reference sample and the sample to be measured after normalization with the stopping power. As a reference sample, a sample obtained by ion-implanting H into Si and muscovite are used.
It is known that muscovite has a hydrogen concentration of 6.5 atomic%.
The H adsorbed on the outermost surface is corrected by subtracting the amount of H adsorbed on the clean Si surface, for example.

The growth cross section of the surface layer may have a columnar structure, but from the viewpoint of slipperiness, a structure with high flatness is desirable, and amorphous is desirable.
In order to improve adhesion to the photosensitive layer and improve surface slip, the lower layer side of the surface layer may be microcrystalline and the outermost surface side may be amorphous.

As the photoreceptor to which the surface layer of the GaZnO film according to the present embodiment is applied, for example, an amorphous silicon photoreceptor mainly composed of silicon atoms and an organic that adopts a function separation type configuration using an organic polymer. Examples include a photoreceptor.
The amorphous silicon photoreceptor mainly composed of silicon atoms may be a positively charged or negatively charged photoreceptor, and a surface layer containing the GaZnO material according to the present embodiment is formed on the charge injection blocking layer provided as an intermediate layer. It may be provided, or a second surface layer containing the GaZnO material according to the present embodiment may be further provided as a surface modification layer on the first surface layer.

Further, the uppermost layer excluding the surface layer of the positively charged or negatively charged amorphous silicon photoconductor for forming the surface layer according to the present embodiment includes a p-type amorphous silicon layer and an n-type amorphous material. quality silicon _{layer, Si x O 1-x:} H _{layer, Si x N 1-x:} H _{layer, Si x C 1-x:} H layer, an amorphous carbon layer, and the like.

  Note that an amorphous silicon photoconductor mainly composed of silicon atoms generally has low chemical stability, and usually a heater needs to be provided inside the photoconductor. However, a film made of the GaZnO material according to the present embodiment. Is used as a charge transport layer on the amorphous silicon photosensitive layer, the chemical stability is high, and an internal heater is not required.

On the other hand, in the case of an organic photoreceptor, a function-integrated type photosensitive layer in which a charge generation layer and a charge transport layer are integrated may be used, or a function-separated type photosensitive layer separated into a charge generation layer and a charge transport layer. good.
In the case of the function separation type, a charge generation layer may be provided on the surface side, or a charge transport layer may be provided on the surface side. The surface layer composed of the GaZnO material according to the present embodiment may be provided directly on these photosensitive layers, or the hardness, expansion coefficient, elasticity, etc. may be adjusted between the surface layer and the photosensitive layer. An intermediate layer may be provided. For example, an intermediate layer (hard layer) having a hardness intermediate between the hardness of the photosensitive layer and the surface layer of the GaZnO material according to the present embodiment may be provided on the photosensitive layer, and the elastic strain may be reduced. You may provide the electric charge transport layer for making small, and a softer (lower hardness) layer than a surface layer.

An electrophotographic photosensitive member is provided with an absorption layer that absorbs short-wavelength light such as ultraviolet rays in order to prevent the photosensitive layer from being decomposed by irradiation with short-wavelength electromagnetic waves other than heat while forming a surface layer. There may be.
In addition, a film having a small band gap may be initially formed at the time of forming the surface layer so that short wavelength light is not irradiated onto the organic photosensitive layer. For example, a Ga _x In _1-x N film (0 ≦ x ≦ 0.99) containing In is used.
In addition, a layer in which an ultraviolet absorber or an antioxidant is dispersed in a polymer resin may be formed by coating, or a layer in which an ultraviolet absorber is mixed may be provided on the charge transport layer.
By providing a layer that absorbs short-wavelength light such as ultraviolet rays as described above before forming the surface layer, not only the influence of ultraviolet rays when forming the surface layer is suppressed, but also in the image forming apparatus. The influence of short wavelength light such as corona discharge during printing and ultraviolet rays from various light sources is suppressed.

The surface layer of the GaZnO material may contain an n-type element or a p-type element for controlling the conductivity type. The surface layer containing these n-type or p-type elements may be a charge injection blocking layer or a charge injection layer. In the case of the charge injection layer, charges are trapped on the surface of the intermediate layer or the photosensitive layer. In the case of negative charging, the n-type layer functions as a charge injection layer, and the p-type layer functions as a charge injection blocking layer. In the case of positive charging, the n-type layer functions as a charge injection blocking layer, and the p-type layer functions as a charge injection layer.
The thickness of the surface layer 4 is preferably in the range of 0.1 μm or more and 10 μm or less from the viewpoints of wear resistance, chemical stability, and light transmittance.

<Method for forming surface layer>
Next, a method for forming a surface layer according to this embodiment will be described. As a method for forming the surface layer of the GaZnO material according to the present embodiment, a known vapor deposition method such as a plasma CVD (Chemical Vapor Deposition) method, a metal organic chemical vapor deposition method, a molecular beam epitaxy method, vapor deposition, sputtering, etc. However, it is desirable to use a remote plasma organometallic chemical deposition method from the viewpoint of obtaining high adhesion.

  FIG. 4A shows an example of the configuration of a film forming apparatus using a remote plasma organometallic chemical deposition method used for forming the GaZnO material according to the present embodiment, and FIG. 4B is a diagram between A1 and A2 of the film forming apparatus 30 shown in FIG. 4A. The cross section in is shown schematically. 10 is a film forming chamber, 11 is an exhaust port, 12 is a base material rotating part, 13 is a base material support member, 14 is a base material which is an object to be processed, 15 is a gas introduction pipe, and 16 is introduced from a gas introduction pipe 15 A shower nozzle having an opening for injecting gas, 17 is a plasma diffusion unit, 18 is a high-frequency power supply unit, 19 is a flat plate electrode, 20 is a gas introduction tube, and 21 is a high-frequency discharge tube unit.

In the film forming apparatus 30 shown in FIGS. 4A and 4B, an exhaust port 11 connected to a vacuum exhaust apparatus (not shown) is provided at one end of the film forming chamber 10. A plasma generator is provided on the side opposite to the provided side.
This plasma generator is disposed in a high-frequency discharge tube portion 21, a high-frequency discharge tube portion 21, a flat plate electrode 19 provided with a discharge surface on the exhaust port 11 side, and disposed outside the high-frequency discharge tube portion 21. The high-frequency power supply unit 18 is connected to the surface of the electrode 19 opposite to the discharge surface. The high-frequency discharge tube portion 21 is connected to a gas introduction tube 20 for supplying gas into the high-frequency discharge tube portion 21, and the other end of the gas introduction tube 20 is a first not shown. Connected to the gas supply.

  Note that instead of the plasma generator provided in the film forming apparatus 30 shown in FIG. 4B, for example, a plasma generator shown in FIG. 5 may be used. This plasma generator comprises a quartz tube 23 and a high-frequency coil 22 provided along the outer peripheral surface of the quartz tube 23, and one end of the quartz tube 23 is connected to the film forming chamber 10 (not shown in FIG. 5). Has been. The other end of the quartz tube 23 is connected to a gas introduction tube 20 for introducing a gas into the quartz tube 23 as in the apparatus shown in FIG. By supplying a high frequency of 13.56 MHz to the high frequency coil 22, a discharge is generated in the quartz tube 23.

  In FIG. 4B, a rod-shaped shower nozzle 16 that is substantially parallel to the discharge surface is connected to the discharge surface side of the plate electrode 19. One end of the shower nozzle 16 is connected to a gas introduction pipe 15, and this gas introduction pipe 15 is connected to a second gas supply source (not shown) provided outside the film forming chamber 10.

In order to introduce oxygen into the film, oxygen and gallium atoms are mixed by mixing oxygen and gas containing oxygen such as N ₂ O and H ₂ O together with Ga and Zn source gases. A film containing zinc atoms is formed. In addition, when oxidation with oxygen is performed after film formation, the oxidation may be performed in a vacuum or in the air. When performed in a vacuum, for example, high-frequency discharge may be performed using oxygen gas diluted with a rare gas or the like to incorporate oxygen into the film. Further, not only oxygen but also a known method such as a thermal diffusion method or an ion implantation method may be employed as a method for incorporating an element into the film.

In this apparatus, for example, N ₂ is introduced from the gas introduction tube 20 to the high-frequency discharge tube 21. A radio wave of 13.56 MHz is supplied to the high frequency power supply unit 18 and the matching circuit, and discharge is generated in the electrode 19 and the plasma diffusion unit 17.

  In the film forming chamber 10, a base material rotating unit 12 is provided, and a cylindrical base material (object to be processed) 14 includes a longitudinal direction of the shower nozzle and an axial direction of the base material (object to be processed) 14. Are attached to the base material rotating part 12 via the base material support member 13 so as to face each other substantially in parallel. During film formation, the base material rotating unit 12 rotates, whereby the base material 14 rotates in the circumferential direction. As the substrate 14, for example, a photoconductor previously laminated up to the photosensitive layer is used.

When forming the surface layer containing the GaZnO material which concerns on this embodiment on the surface (outer peripheral surface) of the base material 14 using this film-forming apparatus 30, it implements as follows, for example.
First, oxygen (O ₂ ) gas (or helium (He) diluted oxygen gas), helium (He) gas, and, if necessary, hydrogen (H ₂ ) gas are supplied from the gas introduction tube 20 into the high-frequency discharge tube portion 21. While being introduced, a radio wave of 13.56 MHz is supplied from the high frequency power supply unit 18 to the plate electrode 19. At this time, the plasma diffusion portion 17 is formed so as to spread radially from the discharge surface side of the flat plate electrode 19 to the exhaust port 11 side. Here, the gas introduced from the gas introduction pipe 20 flows through the film forming chamber 10 from the plate electrode 19 side to the exhaust port 11 side. The plate electrode 19 may be one in which the electrode is surrounded by a ground shield.

Next, as a source gas, for example, a trimethylgallium gas and an organic zinc (for example, dimethylzinc or diethylzinc) gas are introduced from the gas introduction pipe 15, and a shower nozzle located on the downstream side of the plate electrode 19 serving as an activating means. 16 and introduced into the film forming chamber 10 through a separate introduction tube 20 and hydrogen or a rare gas mixed with oxygen to cause glow discharge to generate hydrogen, gallium, A non-single-crystal film containing zinc and oxygen is formed.
At the time of film formation, trimethylgallium and organic zinc are introduced into the gas introduction tube 15 as gases from separate containers, but the ratio of the number of zinc atoms to the number of gallium atoms (number of zinc atoms / number of gallium atoms) is 0. The ratio of the number of oxygen atoms to the sum of the numbers of atoms of gallium and zinc is 01 or more and 0.6 or less [number of oxygen atoms / (number of gallium atoms + number of zinc atoms)] is 1.0 or more and 1 Adjust the concentration of each raw material gas so that it becomes 6 or less.

In the case of using an organic photoreceptor having an organic photosensitive layer, the surface temperature of the base material 14 at the time of forming the surface layer is preferably 150 ° C. or lower, more preferably 100 ° C. or lower, particularly 30 ° C. or higher and 100 ° C. or lower. desirable. Even if the temperature of the surface of the substrate 14 is 150 ° C. or less at the beginning of the film formation, the organic photosensitive layer may be damaged by heat if it becomes higher than 150 ° C. due to the influence of plasma. In consideration of the above, the surface temperature of the substrate 14 may be controlled.
On the other hand, when an amorphous silicon photoconductor is used, the surface temperature of the base material 14 when the surface layer is formed is, for example, 50 ° C. or higher and 350 ° C. or lower.

The surface temperature of the substrate 14 may be controlled by heating and / or cooling means (not shown), or may be left to a natural temperature increase during discharge. When heating the base material 14, a heater may be installed outside or inside the base material 14. When the substrate 14 is cooled, a cooling gas or liquid may be circulated inside the substrate 14. Further, for example, a rare gas such as He may be used alone instead of H ₂ , or it may be mixed with H ₂ gas and flowed through the gas introduction tube 20 to perform glow discharge.
In order to avoid an increase in the surface temperature of the substrate 14 due to electric discharge, it is effective to adjust a high-energy gas flow that strikes the surface of the substrate 14. In this case, conditions such as the gas flow rate, discharge output, and pressure are adjusted so as to become the target temperature.

A dopant may be added to the surface layer in order to control its conductivity type. As a dopant doping method during film formation, SiH ₃ , SnH ₄ or the like is used for n-type, and biscyclopentadienylmagnesium, dimethyl calcium, dimethylstrontium, or the like is used in a gas state for p-type. . In order to dope the dopant element into the surface layer, a known method such as a thermal diffusion method or an ion implantation method may be employed.
Specifically, for example, by introducing a gas containing at least one dopant element into the film forming chamber 10 through the gas introduction pipe 15 and the shower nozzle 16, a conductive type such as n-type or p-type. A surface layer is obtained.

In the film formation apparatus described with reference to FIGS. 4A, 4B, and 5, active nitrogen or active hydrogen formed by discharge energy may be independently controlled by providing a plurality of active apparatuses, NH _3, etc. You may use the gas containing a nitrogen atom and a hydrogen atom. Further, H ₂ may be added. Alternatively, conditions under which active hydrogen is liberated from an organometallic compound may be used. By doing so, activated carbon atoms, gallium atoms, nitrogen atoms, hydrogen atoms, etc. exist on the surface of the base material 14 in a controlled state. Then, the activated hydrogen atom has an effect of desorbing hydrogen of a hydrocarbon group such as a methyl group or an ethyl group constituting the organometallic compound as a molecule. For this reason, a hard film (surface layer) constituting a three-dimensional bond is formed.

  The plasma generating means of the film forming apparatus shown in FIGS. 4A, 4B, and 5 uses a high-frequency oscillation device, but is not limited to this. For example, a microwave oscillating device or an electrocyclotron resonance type or helicon plasma type device may be used. Further, in the case of a high-frequency oscillation device, it may be inductive or capacitive. Furthermore, two or more of these devices may be used in combination, or two or more of the same types of devices may be used. In order to suppress an increase in the surface temperature of the substrate 14 by plasma irradiation, a high-frequency oscillation device is desirable, but a device for preventing heat irradiation may be provided.

  When two or more different plasma generators (plasma generating means) are used, it is desirable that discharges occur simultaneously at the same pressure. Moreover, you may provide a pressure difference in the area | region to discharge and the area | region (part in which the base material was installed) to form into a film. These apparatuses may be arranged in series with respect to the gas flow formed in the film forming apparatus from the part where the gas is introduced to the part where the gas is discharged. You may arrange | position so that it may oppose.

For example, when two types of plasma generating means are installed in series with respect to the gas flow, taking the film forming apparatus 30 shown in FIG. 4A as an example, a discharge is caused in the film forming chamber 10 using the shower nozzle 16 as an electrode. Used as a second plasma generator. In this case, for example, a high frequency voltage is applied to the shower nozzle 16 through the gas introduction pipe 15 to cause discharge in the film forming chamber 10 using the shower nozzle 16 as an electrode. Alternatively, instead of using the shower nozzle 16 as an electrode, a cylindrical electrode is provided between the base material 14 and the plate electrode 19 in the film forming chamber 10, and this film is used to form the film forming chamber. 10 is caused to discharge.
In addition, when two different types of plasma generators are used under the same pressure, for example, when using a microwave oscillator and a high-frequency oscillator, the excitation energy of the excited species can be changed greatly, which is effective for controlling the film quality. is there. Moreover, you may perform discharge by atmospheric pressure vicinity (70000 Pa or more and 110000 Pa or less). When discharging near atmospheric pressure, it is desirable to use He as a carrier gas.

In addition to the above-described methods, a normal metal organic vapor phase epitaxy method or a molecular beam epitaxy method is used for forming the surface layer or the like. However, in the film formation by these methods, active nitrogen and / or Use of active hydrogen and active oxygen is effective for lowering the temperature. In this case, as the nitrogen source, a gas such as N ₂ , NH ₃ , NF ₃ , N ₂ H ₄ , methyl hydrazine or the like, or a vaporized liquid, or a gas bubbled with a carrier gas is used. As the oxygen raw material, oxygen, H ₂ O, CO, CO ₂ , NO, N ₂ O, or the like is used.

As film formation conditions, for example, when discharging is performed by high-frequency discharge, it is desirable that the frequency be in the range of 10 kHz to 50 MHz for film formation at a low temperature. Further, the output depends on the size of the substrate, but it is desirable that the output be in the range of 0.01 W / cm ² or more and 0.2 W / cm ² or less with respect to the surface area of the substrate. The rotation speed of the substrate is preferably in the range of 0.1 rpm to 500 rpm.

  Next, a process cartridge and an image forming apparatus provided with the electrophotographic photosensitive member according to this embodiment will be described.

<Process cartridge and image forming apparatus>
A process cartridge and an image forming apparatus using the electrophotographic photosensitive member of this embodiment will be described.
The process cartridge of the present embodiment is not particularly limited as long as it includes the electrophotographic photosensitive member of the present embodiment. Specifically, the electrophotographic photosensitive member of the present embodiment, a charging unit, a developing unit, and a cleaning device are used. And at least one selected from the above means as a unit, and has a configuration that is detachable from the main body of the image forming apparatus.

  The image forming apparatus according to the present embodiment is not particularly limited as long as it includes the electrophotographic photosensitive member according to the present embodiment. Specifically, the electrophotographic photosensitive member according to the present embodiment and the electrophotographic photosensitive member are provided. Charging means for charging the surface of the body, exposure means (electrostatic latent image forming means) for exposing the surface of the electrophotographic photosensitive member charged by the charging means to form an electrostatic latent image, and electrostatic latent image The image forming apparatus includes a developing unit that forms a toner image by developing with a developer containing toner, and a transfer unit that transfers the toner image to a recording medium. The image forming apparatus of the present embodiment may be a so-called tandem machine having a plurality of photoreceptors corresponding to the toners of the respective colors. In this case, all the photoreceptors are the electrophotographic photoreceptors of the embodiment. Is desirable. The toner image may be transferred by an intermediate transfer system using an intermediate transfer member.

  Since the process cartridge and the image forming apparatus according to the present embodiment include the electrophotographic photosensitive member according to the present embodiment in which the decrease in sensitivity is suppressed, generation of scratches and wear on the surface of the photosensitive member are suppressed even during long-term use. The occurrence of image unevenness is also suppressed.

  FIG. 6 schematically shows an example of the basic configuration of the process cartridge according to the present embodiment. A process cartridge 100 shown in FIG. 6 includes an electrophotographic photosensitive member 107, a charging unit 108, a developing unit 111, a cleaning unit 113, an opening 105 for exposure, and a static eliminator 114, and a case 101 and a mounting rail 103. Used and combined. The process cartridge 100 is detachable from the main body of the image forming apparatus including the transfer unit 112, the fixing device 115, and other components (not shown). A forming apparatus is configured.

  FIG. 7 schematically shows an example of the basic configuration of the image forming apparatus of the present embodiment. The image forming apparatus 200 shown in FIG. 7 is charged by an electrophotographic photosensitive member 207, a charging unit 208 that charges the electrophotographic photosensitive member 207 by a contact method, a power source 209 connected to the charging unit 208, and a charging unit 208. An exposure unit 210 for exposing the electrophotographic photosensitive member 207, a developing unit 211 for developing a portion exposed by the exposure unit 210, and a transfer unit 212 for transferring an image developed on the electrophotographic photosensitive member 207 by the developing unit 211. A cleaning device 213 for removing the toner remaining on the surface of the electrophotographic photosensitive member 207 after the transfer, a static eliminator 214 for removing residual charges on the surface of the electrophotographic photosensitive member, and a toner image transferred to the recording medium. A fixing device 215 for fixing.

  The cleaning unit 213 in the process cartridge and the image forming apparatus of the present embodiment is not particularly limited, but preferably includes a cleaning blade. The cleaning blade is likely to damage the surface of the photosensitive member and promote wear compared to other cleaning means such as a brush. However, since the process cartridge and the image forming apparatus according to the present embodiment use the electrophotographic photosensitive member according to the present embodiment, generation of scratches and wear on the surface of the photosensitive member are suppressed even when used for a long time. .

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.
<Example 1>
An organic photoreceptor was produced in which an undercoat layer (charge injection blocking layer), a charge generation layer, and a charge transport layer were sequentially formed on an aluminum support (outer diameter: 84 mm) according to the following steps.
The undercoat layer serving as the charge injection blocking layer is composed of 20 parts by mass of a zirconium compound (trade name: Organochix ZC540, manufactured by Matsumoto Pharmaceutical Co., Ltd.), 2.5 parts by mass of a silane compound (trade name: A1100, manufactured by Nihon Unicar). By stirring and mixing 10 parts by weight of butyral resin (trade name: ESREC BM-S, manufactured by Sekisui Chemical Co., Ltd.) and 45 parts by weight of butanol, this mixture is applied to the surface of the support and heated and dried at 150 ° C. for 10 minutes. An undercoat layer having a thickness of 1.0 μm was used.

  Next, 1 part by mass of chlorogallium phthalocyanine as a charge generating material is mixed with 1 part by mass of polyvinyl butyral (trade name: S-REC BM-S manufactured by Sekisui Chemical Co., Ltd.) and 100 parts by mass of n-butyl acetate, and the mixture is mixed with glass beads. At the same time, it was dispersed for 1 hour with a paint shaker to obtain a dispersion for forming a charge generation layer. This dispersion was applied on the undercoat layer by an immersion method and dried at 100 ° C. for 10 minutes to obtain a charge generation layer having a thickness of 0.15 μm.

  Next, 2 parts by mass of a compound represented by the following structural formula (1) and 3 parts by mass of a polymer compound (viscosity average molecular weight 39000) represented by the following structural formula (2) are dissolved in 20 parts by mass of chlorobenzene. A coating solution for forming a charge transport layer was obtained.

  This coating solution was applied onto the charge generation layer by an immersion method and heated at 110 ° C. for 40 minutes to obtain a charge transport layer having a thickness of 20 μm.

The photoconductor obtained as described above was attached to the base material support member 13 in the apparatus shown in FIG. 4A, and the inside of the chamber 10 was evacuated through the exhaust port 11.
He diluted oxygen gas 20 sccm and He gas 100 sccm, respectively, are introduced into the electrode section 19 having a diameter of 50 mm from the gas introduction tube 20, and a 13.56 MHz radio wave is set to an output 50 W via the high frequency power supply 18 and the matching circuit. Matching was performed and discharging was performed. The reflected wave at this time was 0 W.

A mixed gas containing 0.2 sccm of trimethylgallium using hydrogen as a carrier and a gas of 0.07 sccm of dimethylzinc were mixed and introduced into the remote plasma from the nozzle 16. At this time, the reaction pressure of trimethylgallium and dimethylzinc measured with a Baratron vacuum gauge was 40 Pa.
The substrate (photoreceptor) was not heated. On the surface of the organic photoreceptor, a temperature measurement sticker (manufactured by Wahl, Temp Plate P / N101) was attached to measure the surface temperature.
In this state, the film was formed for 60 minutes, and an amorphous film containing 0.4 μm thickness, hydrogen, gallium, zinc, and oxygen was formed on the organic photoreceptor. The temperature measurement result by the temperature measurement sticker was 45 ° C.

From the elemental analysis by RBS and HFS of the film simultaneously formed on the Si substrate, Ga and Zn are 1: 0.38 (atomic ratio), and the number of oxygen atoms with respect to the sum of the respective atomic numbers of Ga and Zn. The ratio was 1.24. Further, hydrogen was contained at 18 atomic% with respect to the total number of atoms of Ga, Zn, O and H in the film.
The contact angle with pure water was 80 °.
This film was transparent, and the surface of the film was not damaged even when rubbed with stainless steel.
It was found that the diffraction image obtained by RHEED (reflection high-energy electron diffraction) was amorphous with no dots or lines.

In order to measure the resistance of the film, a copper wire was bonded to the Al portion of the 2 mm diameter Au deposition electrode and the base material with a silver paste to form a lead wire. The volume resistance was determined from the voltage / current value at an electric field of 10 ⁵ (V / cm). The resistance was 8 × 10 ¹⁰ Ωcm, and the chargeability was 5 V / μm. The volume resistance is a value measured with an Agilent 4155C semiconductor parameter analyzer, and the charging property is a value measured with a surface potential meter Model 334 and Model 555P-1 probe manufactured by Trek.
It was determined by measuring the stylus level. As the sample substrate, a Si wafer having a thickness of 400 μm cut to 5 × 10 mm was used. The level difference between the non-film-formed part and the film-formed part formed with a polyimide adhesive tape for fixing on the surface of the photoconductor was measured with Surfcom 550A manufactured by Tokyo Seimitsu Co., Ltd.

Further, the photoconductor was mounted on “DocuCenter Color 500” manufactured by Fuji Xerox Co., Ltd., and image quality evaluation was performed under the following conditions in a high temperature and high humidity environment (temperature: 28 ° C., humidity: 80% RH).
(White line)
The white streak defect on the image was evaluated with respect to the halftone image (image density 30%) after 20,000 sheets were printed. The evaluation criteria are as follows.

-Evaluation criteria-
A: No white streak-like image defect is observed.
B: Slight white streak-like image defects that are thought to be caused by scratches on the photoreceptor are slightly observed, but are practically acceptable.
C: Many white streak-like image defects considered to be caused by scratches on the photoreceptor were observed, which exceeded the practically acceptable range.

(Image density)
After printing 1000 sheets, 100 solid images with 100% area coverage were printed continuously, and the image density of the obtained images was evaluated according to the following evaluation criteria.

-Evaluation criteria-
A: No decrease in image density is observed even after printing 100 sheets.
B: In the case of more than 90 sheets and less than 100 sheets, a slight decrease in image density is observed after printing, but this is practically acceptable.
C: In the case of more than 70 sheets and 90 sheets or less, although a slight decrease in image density is observed after printing, it is within a practically acceptable range.
D: At 70 sheets or less, the image density was reduced at first glance, which exceeded the practically acceptable range.

(Image blur)
Image blurring was performed by wiping only a part of the surface of the photoconductor to remove water-soluble discharge products after printing 20,000 sheets in image quality evaluation.
After that, a halftone image (image density 30%) is printed, and the presence or absence of a density difference corresponding to a portion where the surface of the photoreceptor is wiped with water is visually confirmed in the halftone image. Evaluation was made according to the following evaluation criteria.

-Evaluation criteria-
A: No difference in density is observed.
B: Although there is a slight difference in density, it is within a practically acceptable range.
C: A difference in density could be confirmed at first glance, which exceeded the practically acceptable range.

(Scratches)
The surface of the photoreceptor after the 20,000-sheet print test in the image quality evaluation was visually observed to check for the presence or absence of scratches on the surface.
The evaluation criteria are as follows.

-Evaluation criteria-
A: No scratches on the surface are observed.
B: Although scratches on the surface are slightly seen, it is within a practically acceptable range.
C: Scratches on the surface could be confirmed at first glance, which exceeded the practically acceptable range.

<Increase in residual potential during repeated use>
First, the residual potential A at a wavelength of 780 nm was measured for the electrophotographic photosensitive member with a protective layer before the print test for 20,000 sheets in the image quality evaluation.
Next, after 20,000 print tests in the above image quality evaluation, the residual potential A at a wavelength of 780 nm was measured for the electrophotographic photosensitive member with a protective layer.
Based on these results, an increase in residual potential (change potential V) during repeated use was evaluated according to the following evaluation criteria.
Overall image quality evaluation A: All items A: white streak, image density, image blur
B: B in item 1-2
C: B in 3 items
D: C for 1 item

In the above print evaluation of Example 1, it was A.
Further, there was no scratch on the surface of the photoreceptor after the print evaluation, and the initial slip was maintained.

<Example 2>
Using the organic photoreceptor prepared up to the charge transport layer in the same procedure as in Example 1, a surface layer of a gallium oxide film containing 0.5 μm in thickness and containing hydrogen and zinc was formed in the same manner as in Example 1. A mixed gas of trimethylgallium 0.15 sccm and dimethylzinc 0.14 sccm was introduced into the remote plasma through the gas introduction tube 15 using hydrogen as a carrier. The plasma is arranged through the slit-shaped diffusion part 17. At this time, the reaction pressure measured with a Baratron vacuum gauge was 40 Pa.

From the RBS and HFS elemental analysis of the film simultaneously formed on the Si substrate, the film formed on the base material has a ratio of Ga and Zn of 1: 0.45 (atomic ratio). The atomic ratio of oxygen to the sum was 1.20.
Further, hydrogen was contained at 19 atomic% with respect to the total number of atoms of Ga, Zn, O and H in the film.
The contact angle with pure water was 80 °.
This film was transparent, and the surface of the film was not damaged even when rubbed with stainless steel.
It was found that the diffraction pattern with RHEED was amorphous with no dots or lines.

In order to measure the resistance of the film, a copper wire was bonded to the Al portion of the 2 mm diameter Au deposition electrode and the base material with a silver paste to form a lead wire. The volume resistance was determined from the voltage / current value at an electric field of 10 ⁵ (V / cm). The resistance was 5 × 10 ¹¹ Ωcm, and the chargeability was 20V.

This film was transparent and the surface of the film was made of stainless steel and was not damaged. Further, it was found that the diffraction pattern with RHEED was amorphous with no dots or lines.
There was little change in the charging characteristics, the residual potential after light irradiation was a change of 20 V or less, and there was almost no influence on the sensitivity from the infrared region to the entire visible region.
Further, regarding the adhesiveness of the film, it was not peeled off even by the adhesive tape, and the surface property was smoother and more slippery than the original organic photoreceptor.

  Further, when mounted on a “DocuCenter Color 500” manufactured by Fuji Xerox Co., Ltd. and printed in a high temperature and high humidity environment as in Example 1, a clear image was obtained. Further, the surface of the photoconductor after the print test in a high temperature and high humidity environment was not damaged, and the initial slip was maintained.

<Example 3>
An n-type Si ₃ N ₁ charge injection blocking layer having a thickness of 3 μm, an i-type amorphous silicon photoconductive layer having a thickness of 20 μm, and a p-type Si ₂ C _{1 having} a thickness of 0.5 μm are formed on an aluminum support. A surface layer of a zinc gallium oxide film was formed under the same conditions as in Example 1 using a negatively charged amorphous silicon photoconductor having a charge injection blocking surface layer and using the apparatus of FIG. 4A.

This film was almost transparent, and the surface of the film was made of stainless steel and was not damaged.
Further, it was found that the diffraction pattern with RHEED was amorphous with no dots or lines.
There was no change in the charging characteristics, the residual potential after light irradiation was a change of 30 V or less, and there was no influence on the sensitivity from the infrared region to the entire visible region.
Further, the adhesiveness was not peeled off even by the adhesive tape, and the surface property was smoother and more slippery than the original amorphous silicon photoreceptor.

  Furthermore, when the printing was evaluated in a high-temperature and high-humidity environment after changing the conditions on the “DocuCenter Color 500” manufactured by Fuji Xerox Co., Ltd., a clear image was obtained. Further, the surface of the photoconductor after the print test in a high temperature and high humidity environment was not damaged, and the initial slip was maintained.

<Example 4>
Using the organic photoreceptor prepared up to the charge transport layer in the same procedure as in Example 1, a surface layer of a gallium oxide film containing 0.5 μm in thickness and containing hydrogen and zinc was formed in the same manner as in Example 1.
At that time, using the same apparatus as shown in FIG. 4A as in Example 1, except that a mixed gas of trimethylgallium 0.2 sccm and dimethylzinc 0.02 sccm was introduced into the remote plasma through the gas introduction tube 15 using hydrogen as a carrier. It was produced under the same conditions as in Example 1. The plasma is arranged through the slit-shaped diffusion part 17. At this time, the reaction pressure measured with a Baratron vacuum gauge was 40 Pa.

<Example 5>
Using the organic photoreceptor prepared up to the charge transport layer in the same procedure as in Example 1, a surface layer of a gallium oxide film containing 0.5 μm in thickness and containing hydrogen and zinc was formed in the same manner as in Example 1.
At that time, the apparatus shown in FIG. 4A same as Example 1 was used, except that a mixed gas of trimethylgallium 0.15 sccm and dimethylzinc 0.2 sccm was introduced into the remote plasma through the gas introduction tube 15 using hydrogen as a carrier. It was produced under the same conditions as in Example 1. The plasma is arranged through the slit-shaped diffusion part 17. At this time, the reaction pressure measured with a Baratron vacuum gauge was 40 Pa.

<Comparative Example 1>
A surface layer of a gallium oxide film containing hydrogen having a thickness of 0.5 μm and containing hydrogen was formed in the same manner as in Example 1 using the organic photoreceptor prepared up to the charge transport layer in the same procedure as in Example 1. At that time, the same conditions as in Example 1 were used except that the same apparatus as in Example 1 shown in FIG. 4A was used and a mixed gas of trimethylgallium 0.3 sccm was introduced into the remote plasma through the gas introduction tube 15 using hydrogen as a carrier. It was made with. The plasma is arranged through the slit-shaped diffusion part 17. At this time, the reaction pressure measured with a Baratron vacuum gauge was 40 Pa.

<Comparative example 2>
Using the organic photoreceptor prepared up to the charge transport layer in the same procedure as in Example 1, a surface layer of a gallium oxide film containing 0.5 μm in thickness and containing hydrogen and zinc was formed in the same manner as in Example 1. At that time, the same apparatus as that of Example 1 shown in FIG. 4A was used, except that a mixed gas of trimethylgallium 0.05 sccm and dimethylzinc 0.4 sccm was introduced into the remote plasma through the gas introduction tube 15 using hydrogen as a carrier. It was produced under the same conditions as in Example 1. The plasma is arranged through the slit-shaped diffusion part 17. At this time, the reaction pressure measured with a Baratron vacuum gauge was 40 Pa.

  The composition ratios and evaluation results of the oxide materials formed in the examples and comparative examples are shown in Table 1 below.

  The case where the oxide material of the present embodiment is used as the surface layer of the electrophotographic photosensitive member has been described above, but the oxide material of the present embodiment is not limited to the surface layer of the electrophotographic photosensitive member, but also the undercoat layer, the charge You may use for other layers, such as a transport layer. In addition, the oxide material of the present embodiment is not limited to the layer constituting the electrophotographic photosensitive member, and for example, an antistatic film for a display of a display device, a charge transport layer for an organic electroluminescent element, a neutralizing gas barrier film, a solar cell It may be widely used for electronic devices other than electrophotographic photoreceptors, such as protective films.

DESCRIPTION OF SYMBOLS 1 Conductive support body, 2 Charge generation layer, 3 Charge transport layer, 4 Surface layer, 5 Undercoat layer, 6 Intermediate layer, 7 Photosensitive layer, 10 Film-forming chamber (vacuum chamber), 11 Exhaust port, 12 Base material rotation Part 13 base material support member 14 base material (object to be treated) 15 gas introduction pipe 16 shower nozzle 17 plasma diffusion part 18 high frequency power supply part 19 quartz pipe 19 plate electrode 20 gas introduction pipe 21 High-frequency discharge tube, 22 High-frequency coil, 23 Quartz tube, 30 Deposition device, 100 Process cartridge, 105 Opening, 107 Electrophotographic photosensitive member, 108 Charging means, 111 Developing means, 112 Transfer means, 113 Cleaning means, 114 Electric appliance, 115 fixing device, 200 image forming apparatus, 207 electrophotographic photosensitive member, 208 charging means, 209 power supply, 210 exposure means, 211 Developing means, 212 Transfer means, 213 Cleaning means, 214 Static eliminator, 215 Fixing device

Claims (8)

Including at least gallium, zinc, and oxygen,
The atomic ratio of the zinc to the gallium (the number of zinc atoms / the number of gallium atoms) is 0.01 or more and 0.6 or less, and
Oxide material in which the ratio of the number of oxygen atoms [the number of oxygen atoms / (the number of gallium atoms + the number of zinc atoms)] to the sum of the number of atoms of gallium and zinc is 1.0 or more and 1.6 or less An oxide film having a conductivity of 1 × 10 ⁵ Ωcm to 1 × 10 ¹³ Ωcm . The oxide film according to claim 1, wherein the oxide material is amorphous. 2. The oxide film according to claim 1, wherein the zinc content is 0.4 atomic% or more and 25 atomic% or less with respect to the sum of the number of atoms of the gallium, the zinc, and the oxygen contained in the oxide material. An electrophotographic photosensitive member having a layer of the oxide film according to any one of claims 1 to 3. An inorganic photosensitive layer;
The oxide film layer according to any one of claims 1 to 3, which is disposed on the inorganic photosensitive layer;
An electrophotographic photosensitive member having: An organic photosensitive layer;
The oxide film layer according to any one of claims 1 to 3, which is disposed on the organic photosensitive layer;
An electrophotographic photosensitive member having:   A process cartridge comprising the electrophotographic photosensitive member according to any one of claims 4 to 6. An electrophotographic photosensitive member according to any one of claims 4 to 6,
Charging means for charging the electrophotographic photoreceptor;
Latent image forming means for forming a latent image on the surface of the charged electrophotographic photosensitive member;
Developing means for developing a latent image formed on the surface of the electrophotographic photosensitive member with a developer containing toner to form a toner image;
Transfer means for transferring a toner image formed on the surface of the electrophotographic photosensitive member to a recording medium;
An image forming apparatus.

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