JP2024037542A - Electrophotographic photoreceptors, process cartridges, and image forming devices - Google Patents

Abstract

An object of the present invention is to provide an electrophotographic photoreceptor that suppresses the occurrence of image deletion. [Solution] A conductive substrate, a photosensitive layer, and an inorganic protective layer containing a metal element M, oxygen O, and hydrogen H are provided in this order, and the inorganic protective layer is disposed on the outer peripheral surface side of the inorganic protective layer. including the first region present and the second region present on the inner peripheral surface side of the inorganic protective layer, and the ratio of the abundance of M-OH bonds to the abundance of M-H bonds in the first region. When R1 (OH/H) and the ratio of the abundance of M-OH bonds to the abundance of M-H bonds in the second region are R2 (OH/H), the following formula (1-1) and An electrophotographic photoreceptor satisfying the following formula (2). Formula (1-1): R1 (OH/H) < 1.0 Formula (2): R1 (OH/H) < R2 (OH/H) [Selection diagram] Figure 1

Description

The present invention relates to an electrophotographic photoreceptor, a process cartridge, and an image forming apparatus.

Patent Document 1 states, ``a substrate, a photosensitive layer, a protective layer containing oxygen and gallium, a first region existing on the outer peripheral surface side, and a first region closer to the substrate than the first region. an electrophotographic photoreceptor comprising, in this order, a protective layer having a second region located on the side and having a larger atomic ratio [oxygen/gallium] than the first region.

Patent No. 5447062

An object of the present invention is to provide an electrophotographic photoreceptor comprising, in this order, a conductive substrate, a photosensitive layer, and an inorganic protective layer containing a metal element M, oxygen O, and hydrogen H. In an electrophotographic photoreceptor including a first region existing on the outer peripheral surface side of the layer and a second region existing on the inner peripheral surface side of the inorganic protective layer, the amount of M--H bonds in the first region The ratio of the abundance of M-OH bonds to the abundance of M-H bonds in the second region is R1 (OH/H), and the ratio of the abundance of M-OH bonds to the abundance of M-H bonds in the second region is R2 (OH/H). In this case, compared to the case where the following formula (1-1) or the following formula (2) is not satisfied, image deletion (charge of the electrostatic latent image formed on the surface of the photoreceptor flows on the surface of the photoreceptor, An object of the present invention is to provide an electrophotographic photoreceptor that suppresses the occurrence of a phenomenon in which a formed image becomes blurred.
Formula (1-1): R1(OH/H)<1.0
Formula (2): R1(OH/H)<R2(OH/H)

Means for solving the above problems include the following means.
<1> A conductive substrate, a photosensitive layer, and an inorganic protective layer containing metal element M, oxygen O, and hydrogen H, in this order,
The inorganic protective layer includes a first region located on the outer peripheral surface side of the inorganic protective layer and a second region located on the inner peripheral surface side of the inorganic protective layer,
The ratio of the abundance of M-OH bonds to the abundance of M-H bonds in the first region is R1 (OH/H), and the ratio of the abundance of M-OH bonds to the abundance of M-H bonds in the second region is R1 (OH/H). An electrophotographic photoreceptor that satisfies the following formula (1-1) and the following formula (2), where the ratio of the abundance of is R2 (OH/H).
Formula (1-1): R1(OH/H)<1.0
Formula (2): R1(OH/H)<R2(OH/H)
<2> The electrophotographic photoreceptor according to <1>, which satisfies the following formula (3-1).
Formula (3-1): 0.3<R2(OH/H)-R1(OH/H)
<3> The electrophotographic photoreceptor according to <2>, which satisfies the following formula (1-2).
Formula (1-2): R1(OH/H)<0.5
<4> The electrophotographic photoreceptor according to any one of <1> to <3>, wherein the metal element M is gallium.
<5> The electrophotographic photoreceptor according to any one of <1> to <4>, wherein the first region has a smaller thickness than the second region.
<6> The thickness of the first region (thickness of the first region/thickness of the second region) with respect to the thickness of the second region is 0.1 or more and 1.0 or less. 5>.
<7> An electrophotographic photoreceptor according to any one of <1> to <6>,
A process cartridge that can be attached to and removed from an image forming apparatus.
<8> The electrophotographic photoreceptor according to any one of <1> to <6>,
a charging device that charges the surface of the electrophotographic photoreceptor;
an electrostatic latent image forming device that forms an electrostatic latent image on the surface of the charged electrophotographic photoreceptor;
a developing device that develops the electrostatic latent image formed on the surface of the electrophotographic photoreceptor to form a toner image using a developer containing toner;
a transfer device that transfers the toner image onto the surface of a recording medium;
An image forming apparatus comprising:

According to the invention according to <1>, in the electrophotographic photoreceptor having a conductive substrate, a photosensitive layer, and an inorganic protective layer containing a metal element M, oxygen O, and hydrogen H in this order, the inorganic protective layer , an electrophotographic photoreceptor including a first region existing on the outer peripheral surface side of the inorganic protective layer and a second region existing on the inner peripheral surface side of the inorganic protective layer; The ratio of the abundance of M-OH bonds to the abundance of bonds is R1(OH/H), and the ratio of the abundance of M-OH bonds to the abundance of M-H bonds in the second region is R2(OH/H). /H), an electrophotographic photoreceptor is provided that suppresses the occurrence of image deletion compared to the case where the formula (1-1) or the formula (2) is not satisfied.
According to the invention according to <2>, an electrophotographic photoreceptor is provided that suppresses the occurrence of image deletion compared to a case where formula (3-1) is not satisfied.
According to the invention according to <3>, an electrophotographic photoreceptor is provided that suppresses the occurrence of image deletion compared to a case where formula (1-2) is not satisfied.
According to the invention according to <4>, an electrophotographic photoreceptor is provided that suppresses the occurrence of image deletion compared to a case where the metal element M is aluminum.
According to the invention according to <5>, there is provided an electrophotographic photoreceptor that suppresses the occurrence of image deletion compared to a case where the film thickness of the first region is larger than the film thickness of the second region. Ru.

According to the invention according to <6>, the thickness of the first region relative to the thickness of the second region (thickness of the first region/thickness of the second region) is less than 0.1. Or, an electrophotographic photoreceptor is provided that suppresses the occurrence of image deletion compared to cases where the ratio exceeds 1.0.
According to the invention according to <7> or <8>, the conductive substrate, the photosensitive layer, and the inorganic protective layer containing metal element M, oxygen O, and hydrogen H are provided in this order, and the inorganic protective layer comprises , an electrophotographic photoreceptor including a first region existing on the outer peripheral surface side of the inorganic protective layer and a second region existing on the inner peripheral surface side of the inorganic protective layer; The ratio of the abundance of M-OH bonds to the abundance of bonds is R1(OH/H), and the ratio of the abundance of M-OH bonds to the abundance of M-H bonds in the second region is R2(OH/H). /H), a process cartridge or a process cartridge equipped with an electrophotographic photoreceptor that suppresses the occurrence of image deletion compared to a case including an electrophotographic photoreceptor that does not satisfy formula (1-1) or formula (2). An image forming apparatus is provided.

FIG. 2 is a schematic cross-sectional view showing an example of a layer structure of an electrophotographic photoreceptor in an image forming apparatus according to the present embodiment. FIG. 3 is a schematic cross-sectional view showing another example of the layer structure of the electrophotographic photoreceptor in the image forming apparatus according to the present embodiment. 1 is a schematic diagram showing an example of a film forming apparatus used for forming an inorganic protective layer of an electrophotographic photoreceptor according to an embodiment of the present invention. 1 is a schematic diagram showing an example of a plasma generation device used for forming an inorganic protective layer of an electrophotographic photoreceptor according to an embodiment of the present invention. 1 is a schematic configuration diagram showing an example of an image forming apparatus including an electrophotographic photoreceptor according to an embodiment. FIG. 2 is a schematic configuration diagram showing another example of an image forming apparatus including an electrophotographic photoreceptor according to the present embodiment.

Hereinafter, an embodiment that is an example of the present invention will be described. These descriptions and examples are illustrative of embodiments and are not intended to limit the scope of the invention.
In the numerical ranges described step by step in this specification, the upper limit value or lower limit value described in one numerical range may be replaced with the upper limit value or lower limit value of another numerical range described step by step. good. Further, in the numerical ranges described in this specification, the upper limit or lower limit of the numerical range may be replaced with the value shown in the Examples.

Each component may contain multiple types of applicable substances.
When referring to the amount of each component in a composition, if there are multiple types of substances corresponding to each component in the composition, unless otherwise specified, the total amount of the multiple types of substances present in the composition means quantity.

<Electrophotographic photoreceptor>
The electrophotographic photoreceptor (hereinafter also referred to as "photoreceptor") according to the present embodiment includes, in this order, a conductive substrate, a photosensitive layer, and an inorganic protective layer containing a metal element M, oxygen O, and hydrogen H. , the inorganic protective layer includes a first region existing on the outer peripheral surface side of the inorganic protective layer and a second region existing on the inner peripheral surface side of the inorganic protective layer, and M- of the first region The ratio of the abundance of M-OH bonds to the abundance of H bonds is R1(OH/H), and the ratio of the abundance of M-OH bonds to the abundance of M-H bonds in the second region is R2( OH/H), the following formula (1-1) and the following formula (2) are satisfied.
Formula (1-1): R1(OH/H)<1.0
Formula (2): R1(OH/H)<R2(OH/H)

In the photoreceptor according to this embodiment, the above configuration suppresses the occurrence of image deletion. The reason is assumed to be as follows.

In a photoreceptor having a conductive substrate, a photosensitive layer, and an inorganic protective layer containing a metal element M, oxygen O, and hydrogen H in this order, the amount of M—OH bonds in the inorganic protective layer may be large. In this case, the resistance on the surface of the photoreceptor decreases, and a phenomenon in which charges flow on the surface of the photoreceptor (hereinafter, this phenomenon is also referred to as "charge flow") may easily occur. As a result, image deletion may easily occur.

In the photoreceptor according to the present embodiment, the ratio R1 (OH/H) of the amount of M--OH bonds to the amount of M--H bonds in the first region satisfies formula (1-1). In the inorganic protective layer containing the metal element M, oxygen O, and hydrogen H, most of the metal element M forms bonds with hydroxy groups or hydrogen atoms. Therefore, by making R1(OH/H) satisfy formula (1-1), the amount of M--OH bonds in the first region decreases. This increases the resistance on the surface of the photoreceptor and suppresses the generation of charge flow.
Further, in the photoreceptor according to the present embodiment, when the ratio of the abundance of M-OH bonds to the abundance of M-H bonds in the second region is R2 (OH/H), the above R1 (OH/H ) and the above R2(OH/H) satisfy formula (2). This increases the proportion of M--OH bonds in the second region compared to the proportion of M--OH bonds in the first region. Therefore, the resistance of the second region is lower than that of the first region, the movement of charges in the thickness direction of the inorganic protective layer is not inhibited, and the function as a photoreceptor is less likely to be inhibited.

From the above, it is presumed that the photoreceptor according to this embodiment suppresses the occurrence of image deletion.

A photoreceptor has a photosensitive layer and an inorganic protective layer in this order on a conductive substrate.
The photosensitive layer may be a single-layer type photosensitive layer in which a charge generation material and a charge transport material are contained in the same photosensitive layer to have integrated functions, or a laminated layer having a charge generation layer and a charge transport layer with separate functions. It may also be a type photosensitive layer.
When the photosensitive layer is a laminated type photosensitive layer, the order of the charge generation layer and the charge transport layer is not particularly limited, but the photoreceptor has the charge generation layer, the charge transport layer, and the inorganic protective layer on the conductive substrate. A configuration having the elements in this order is preferable. Further, the photoreceptor may include layers other than these layers.

FIG. 1 is a schematic cross-sectional view showing an example of the layer structure of a photoreceptor in an image forming apparatus according to this embodiment. The photoreceptor 107A shown in FIG. 1 has a structure in which a subbing layer 101 is provided on a conductive substrate 104, and a charge generation layer 102, a charge transport layer 103, and an inorganic protective layer 106 are sequentially formed thereon. . In the photoreceptor 107A, a photosensitive layer 105 is configured with a charge generation layer 102 and a charge transport layer 103 whose functions are separated.

Further, FIG. 2 is a schematic cross-sectional view showing another example of the layer structure of the photoreceptor in the image forming apparatus according to the present embodiment. The photoreceptor 107B shown in FIG. 2 has a structure in which a subbing layer 101 is provided on a conductive substrate 104, and a photosensitive layer 105 and an inorganic protective layer 106 are sequentially formed. In the photoreceptor 107B, a single-layer type photosensitive layer is constructed in which a charge generating material and a charge transporting material are contained in the same photosensitive layer 105 to have integrated functions.
Note that the photoreceptor in this embodiment may or may not be provided with the subbing layer 101.

The details of the photoreceptor in this embodiment will be described below, but the reference numerals will be omitted.

(Conductive substrate)
Examples of the conductive substrate include metal plates, metal drums, and metal belts containing metals (aluminum, copper, zinc, chromium, nickel, molybdenum, vanadium, indium, gold, platinum, etc.) or alloys (stainless steel, etc.). can be mentioned. Examples of conductive substrates include paper, resin films, belts, etc. coated with, vapor-deposited, or laminated with conductive compounds (e.g., conductive polymers, indium oxide, etc.), metals (e.g., aluminum, palladium, gold, etc.), or alloys. can also be mentioned. Here, "conductivity" means that the volume resistivity is less than 10 ¹³ Ωcm.

When the electrophotographic photoreceptor is used in a laser printer, the surface of the conductive substrate has a centerline average roughness Ra of 0.04 μm or more and 0.5 μm for the purpose of suppressing interference fringes that occur when irradiated with laser light. It is preferable that the surface be roughened. Note that when incoherent light is used as a light source, surface roughening to prevent interference fringes is not particularly necessary, but it is suitable for longer life because it suppresses the occurrence of defects due to unevenness on the surface of the conductive substrate.

Examples of surface roughening methods include wet honing, which is performed by suspending an abrasive in water and spraying it on the conductive substrate, and centerless grinding, which is performed by pressing the conductive substrate against a rotating grindstone and grinding it continuously. , anodizing treatment, etc.

The surface roughening method involves dispersing conductive or semiconductive powder in a resin to form a layer on the surface of the conductive substrate, without roughening the surface of the conductive substrate. Another example is a method of roughening the surface using particles dispersed in the layer.

Surface roughening treatment by anodic oxidation is a method of forming an oxide film on the surface of a conductive substrate by anodic oxidation in an electrolyte solution using a metal (for example, aluminum) conductive substrate as an anode. Examples of the electrolyte solution include sulfuric acid solution and oxalic acid solution. However, the porous anodic oxide film formed by anodic oxidation is chemically active as it is, is easily contaminated, and has large resistance fluctuations depending on the environment. Therefore, for a porous anodic oxide film, the micropores of the oxide film are blocked by volume expansion caused by a hydration reaction with pressurized steam or boiling water (metal salts such as nickel may be added) to achieve more stable hydrated oxidation. It is preferable to perform a sealing process to convert the material into a material.

The thickness of the anodic oxide film is preferably, for example, 0.3 μm or more and 15 μm or less. When the film thickness is within the above range, barrier properties against injection tend to be exhibited, and increases in residual potential due to repeated use tend to be suppressed.

The conductive substrate may be treated with an acidic treatment liquid or treated with boehmite.
The treatment with the acidic treatment liquid is carried out, for example, as follows. First, an acidic treatment solution containing phosphoric acid, chromic acid, and hydrofluoric acid is prepared. The blending ratio of phosphoric acid, chromic acid, and hydrofluoric acid in the acidic treatment solution is, for example, phosphoric acid in the range of 10% by mass to 11% by mass, chromic acid in the range of 3% to 5% by mass, and hydrofluoric acid in the range of 3% to 5% by mass. The range is 0.5% by mass or more and 2% by mass or less, and the overall concentration of these acids is preferably in the range of 13.5% by mass or more and 18% by mass or less. The treatment temperature is preferably, for example, 42°C or higher and 48°C or lower. The thickness of the coating is preferably 0.3 μm or more and 15 μm or less.

The boehmite treatment is performed, for example, by immersion in pure water at 90° C. or higher and 100° C. or lower for 5 minutes to 60 minutes, or by contacting with heated steam at 90° C. or higher and 120° C. or lower for 5 minutes to 60 minutes. The thickness of the coating is preferably 0.1 μm or more and 5 μm or less. This can be further anodized using an electrolyte solution with low film solubility, such as adipic acid, boric acid, borate, phosphate, phthalate, maleate, benzoate, tartrate, or citrate. good.

(subbing layer)
The subbing layer is, for example, a layer containing inorganic particles and a binder resin.

Examples of the inorganic particles include inorganic particles having a powder resistance (volume resistivity) of 10 ² Ωcm or more and 10 ¹¹ Ωcm or less.
Among these, as the inorganic particles having the above-mentioned resistance value, metal oxide particles such as tin oxide particles, titanium oxide particles, zinc oxide particles, and zirconium oxide particles are preferable, and zinc oxide particles are particularly preferable.

The specific surface area of the inorganic particles measured by the BET method is preferably 10 m ² /g or more, for example.
The volume average particle diameter of the inorganic particles is, for example, 50 nm or more and 2000 nm or less (preferably 60 nm or more and 1000 nm or less).

The content of the inorganic particles is, for example, preferably 10% by mass or more and 80% by mass or less, more preferably 40% by mass or more and 80% by mass or less, based on the binder resin.

The inorganic particles may be surface-treated. Two or more types of inorganic particles with different surface treatments or different particle sizes may be used as a mixture.

Examples of the surface treatment agent include silane coupling agents, titanate coupling agents, aluminum coupling agents, and surfactants. In particular, silane coupling agents are preferred, and silane coupling agents having an amino group are more preferred.

Examples of the silane coupling agent having an amino group include 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-amino Examples include, but are not limited to, propylmethyldimethoxysilane, N,N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, and the like.

Two or more types of silane coupling agents may be used in combination. For example, a silane coupling agent having an amino group and another silane coupling agent may be used together. Examples of other silane coupling agents include vinyltrimethoxysilane, 3-methacryloxypropyl-tris(2-methoxyethoxy)silane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 3-glyoxypropyl-tris(2-methoxyethoxy)silane. Sidoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-( Examples include, but are not limited to, aminoethyl)-3-aminopropylmethyldimethoxysilane, N,N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, and 3-chloropropyltrimethoxysilane. It's not a thing.

The surface treatment method using the surface treatment agent may be any known method, and may be either a dry method or a wet method.

The amount of the surface treatment agent to be treated is preferably, for example, 0.5% by mass or more and 10% by mass or less based on the inorganic particles.

Here, it is preferable for the undercoat layer to contain an electron-accepting compound (acceptor compound) together with inorganic particles, from the viewpoint of improving long-term stability of electrical properties and carrier blocking properties.

Examples of electron-accepting compounds include quinone compounds such as chloranil and bromoanil; tetracyanoquinodimethane compounds; 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitro-9-fluorenone, etc. Fluorenone compound; 2-(4-biphenyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole, 2,5-bis(4-naphthyl)-1,3,4- Oxadiazole compounds such as oxadiazole, 2,5-bis(4-diethylaminophenyl)-1,3,4oxadiazole; xanthone compounds; thiophene compounds; 3,3',5,5'tetra- Diphenoquinone compounds such as t-butyldiphenoquinone; electron transporting substances such as benzophenone compounds; and the like.
In particular, as the electron-accepting compound, a compound having an anthraquinone structure is preferred. Preferred examples of the compound having an anthraquinone structure include hydroxyanthraquinone compounds, aminoanthraquinone compounds, aminohydroxyanthraquinone compounds, etc. Specifically, examples include anthraquinone, alizarin, quinizarin, anthralphine, purpurin, and derivatives thereof. preferable.

The electron-accepting compound may be contained in the undercoat layer in a dispersed manner with the inorganic particles, or may be contained in a state attached to the surface of the inorganic particles.

Examples of the method for attaching the electron-accepting compound to the surface of the inorganic particles include a dry method and a wet method.

In the dry method, for example, while stirring inorganic particles with a mixer with a large shearing force, an electron-accepting compound is dropped directly or dissolved in an organic solvent, and the electron-accepting compound is sprayed with dry air or nitrogen gas. This is a method of adhering to the surface of inorganic particles. When dropping or spraying the electron-accepting compound, it is preferable to do so at a temperature below the boiling point of the solvent. After dropping or spraying the electron-accepting compound, baking may be performed at a temperature of 100° C. or higher. There are no particular restrictions on the baking temperature and time as long as the electrophotographic properties can be obtained.

In the wet method, for example, an electron-accepting compound is added while dispersing inorganic particles in a solvent using stirring, ultrasonic waves, a sand mill, an attritor, a ball mill, etc., and after stirring or dispersion, the solvent is removed and the electron-accepting compound is added. This is a method in which a receptive compound is attached to the surface of an inorganic particle. The solvent can be removed, for example, by filtration or distillation. After removing the solvent, baking may be further performed at 100° C. or higher. Baking is not particularly limited as long as the temperature and time are such that electrophotographic properties can be obtained. In the wet method, the water contained in the inorganic particles may be removed before adding the electron-accepting compound, examples of which include removing the water while stirring and heating it in a solvent, and removing it by azeotroping with the solvent. Can be mentioned.

Note that the electron-accepting compound may be attached before or after the inorganic particles are subjected to surface treatment with a surface treatment agent, or may be carried out simultaneously with the attachment of the electron-accepting compound and the surface treatment with the surface treatment agent.

The content of the electron-accepting compound is, for example, preferably 0.01% by mass or more and 20% by mass or less, and preferably 0.01% by mass or more and 10% by mass or less based on the inorganic particles.

Examples of the binder resin used in the undercoat layer include acetal resin (for example, polyvinyl butyral), polyvinyl alcohol resin, polyvinyl acetal resin, casein resin, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, and unsaturated polyester. Resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, urea resin, phenol resin, phenol-formaldehyde resin, melamine resin, Known materials include known polymer compounds such as urethane resins, alkyd resins, and epoxy resins; zirconium chelate compounds; titanium chelate compounds; aluminum chelate compounds; titanium alkoxide compounds; organic titanium compounds; and silane coupling agents.
Examples of the binder resin used in the undercoat layer include charge transporting resins having a charge transporting group, conductive resins (eg, polyaniline, etc.), and the like.

Among these, resins that are insoluble in the coating solvent of the upper layer are suitable as the binder resin for the undercoat layer, and in particular, urea resins, phenol resins, phenol-formaldehyde resins, melamine resins, urethane resins, and unsaturated polyesters are suitable. Thermosetting resins such as resins, alkyd resins, and epoxy resins; at least one resin selected from the group consisting of polyamide resins, polyester resins, polyether resins, methacrylic resins, acrylic resins, polyvinyl alcohol resins, and polyvinyl acetal resins; Resins obtained by reaction with curing agents are preferred.
When using a combination of two or more of these binder resins, the mixing ratio is determined as necessary.

The undercoat layer may contain various additives to improve electrical properties, environmental stability, and image quality.
Examples of additives include known materials such as polycyclic condensation type and azo type electron transport pigments, zirconium chelate compounds, titanium chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, and silane coupling agents. It will be done. The silane coupling agent is used for surface treatment of inorganic particles as described above, but it may also be added to the undercoat layer as an additive.

Examples of the silane coupling agent as an additive include vinyltrimethoxysilane, 3-methacryloxypropyl-tris(2-methoxyethoxy)silane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3- Glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2- Examples include (aminoethyl)-3-aminopropylmethyldimethoxysilane, N,N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, and 3-chloropropyltrimethoxysilane.

Examples of zirconium chelate compounds include zirconium butoxide, zirconium ethyl acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, acetoacetate ethyl zirconium butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate, Zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide, and the like.

Examples of titanium chelate compounds include tetraisopropyl titanate, tetra-n-butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, and titanium lactate ammonium salt. , titanium lactate, titanium lactate ethyl ester, titanium triethanolaminate, polyhydroxytitanium stearate, and the like.

Examples of the aluminum chelate compound include aluminum isopropylate, monobutoxyaluminum diisopropylate, aluminum butyrate, diethylacetoacetate aluminum diisopropylate, aluminum tris (ethylacetoacetate), and the like.

These additives may be used alone or as a mixture or polycondensate of multiple compounds.

The undercoat layer preferably has a Vickers hardness of 35 or more.
The surface roughness (ten-point average roughness) of the undercoat layer ranges from 1/(4n) (n is the refractive index of the upper layer) to 1/2 of the exposure laser wavelength λ used to suppress moiré images. It is good to have it adjusted to
Resin particles or the like may be added to the undercoat layer to adjust the surface roughness. Examples of the resin particles include silicone resin particles and crosslinked polymethyl methacrylate resin particles. Further, the surface of the undercoat layer may be polished to adjust the surface roughness. Examples of the polishing method include buffing, sandblasting, wet honing, and grinding.

There are no particular restrictions on the formation of the undercoat layer, and well-known formation methods may be used. and heat as necessary.

As the solvent for preparing the coating solution for forming the undercoat layer, known organic solvents such as alcohol solvents, aromatic hydrocarbon solvents, halogenated hydrocarbon solvents, ketone solvents, ketone alcohol solvents, and ether solvents can be used. Examples include solvents and ester solvents.
Specific examples of these solvents include methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, Common organic solvents include n-butyl acetate, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, and toluene.

Examples of methods for dispersing inorganic particles when preparing a coating solution for forming an undercoat layer include known methods such as a roll mill, a ball mill, a vibrating ball mill, an attriter, a sand mill, a colloid mill, and a paint shaker.

Examples of methods for applying the coating solution for forming an undercoat layer onto the conductive substrate include blade coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating. For example, conventional methods such as

The thickness of the undercoat layer is, for example, preferably 15 μm or more, more preferably 20 μm or more and 50 μm or less.

(middle class)
Although not shown, an intermediate layer may be further provided between the conductive substrate and the undercoat layer or between the undercoat layer and the photosensitive layer.
The intermediate layer is, for example, a layer containing resin. Examples of the resin used for the intermediate layer include acetal resin (e.g., polyvinyl butyral), polyvinyl alcohol resin, polyvinyl acetal resin, casein resin, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, Examples include polymeric compounds such as polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, and melamine resin.
The intermediate layer may be a layer containing an organometallic compound. Examples of the organometallic compound used in the intermediate layer include organometallic compounds containing metal atoms such as zirconium, titanium, aluminum, manganese, and silicon.
The compounds used in these intermediate layers may be used alone or as a mixture or polycondensate of a plurality of compounds.

Among these, the intermediate layer is preferably a layer containing an organometallic compound containing a zirconium atom or a silicon atom.

There are no particular restrictions on the formation of the intermediate layer, and well-known formation methods may be used. This is done by heating according to the conditions.
As a coating method for forming the intermediate layer, conventional methods such as dip coating, push-up coating, wire bar coating, spray coating, blade coating, knife coating, and curtain coating can be used.

The thickness of the intermediate layer is, for example, preferably set in a range of 0.1 μm or more and 3 μm or less. Note that the intermediate layer may be used as a subbing layer.

(charge generation layer)
The charge generation layer is, for example, a layer containing a charge generation material and a binder resin. Further, the charge generation layer may be a deposited layer of a charge generation material. The vapor-deposited layer of charge-generating material is suitable when using a non-coherent light source such as a light emitting diode (LED) or an electro-luminescence (EL) image array.

Examples of the charge generating material include azo pigments such as bisazo and trisazo; condensed aromatic pigments such as dibromoanthanthrone; perylene pigments; pyrrolopyrrole pigments; phthalocyanine pigments; zinc oxide; and trigonal selenium.

Among these, it is preferable to use a metal phthalocyanine pigment or a metal-free phthalocyanine pigment as the charge-generating material in order to make it compatible with laser exposure in the near-infrared region. Specifically, for example, hydroxygallium phthalocyanine; chlorogallium phthalocyanine; dichlorotin phthalocyanine; and titanyl phthalocyanine are more preferable.

On the other hand, in order to be compatible with laser exposure in the near-ultraviolet region, charge-generating materials include condensed aromatic pigments such as dibromoanthanthrone; thioindigo pigments; porphyrazine compounds; zinc oxide; trigonal selenium; and bisazo pigments. etc. are preferred.

The charge-generating material described above may also be used when using an incoherent light source such as an LED or an organic EL image array that has an emission center wavelength of 450 nm or more and 780 nm or less, but from the viewpoint of resolution, the photosensitive layer should be 20 μm or less in thickness. When used in a thin film, the electric field strength in the photosensitive layer becomes high, and a decrease in charging due to charge injection from the substrate tends to cause image defects called so-called black spots. This becomes noticeable when charge generating materials such as trigonal selenium and phthalocyanine pigments, which are p-type semiconductors and tend to generate dark current, are used.

On the other hand, when n-type semiconductors such as condensed aromatic pigments, perylene pigments, and azo pigments are used as charge-generating materials, dark current is less likely to occur, and image defects called sunspots can be suppressed even in thin films. .
Note that the n-type is determined by the polarity of the flowing photocurrent using the commonly used time-of-flight method, and the n-type is determined if it is easier to flow electrons as carriers than holes.

The binder resin used in the charge generation layer is selected from a wide range of insulating resins, and the binder resin is selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, polyvinylpyrene, and polysilane. You may choose.
Examples of the binder resin include polyvinyl butyral resin, polyarylate resin (polycondensate of bisphenols and aromatic divalent carboxylic acid, etc.), polycarbonate resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, Examples include polyamide resin, acrylic resin, polyacrylamide resin, polyvinylpyridine resin, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol resin, polyvinylpyrrolidone resin, and the like. Here, "insulating" means that the volume resistivity is 10 ¹³ Ωcm or more.
These binder resins may be used alone or in combination of two or more.

Note that the blending ratio of the charge generating material and the binder resin is preferably within the range of 10:1 to 1:10 in terms of mass ratio.

The charge generation layer may also contain other well-known additives.

There are no particular restrictions on the formation of the charge generation layer, and well-known formation methods may be used. and heat as necessary. Note that the charge generation layer may be formed by vapor deposition of a charge generation material. Formation of the charge generation layer by vapor deposition is particularly suitable when a condensed aromatic pigment or perylene pigment is used as the charge generation material.

Examples of the solvent for preparing the coating solution for forming the charge generation layer include methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, and n-acetic acid. -butyl, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, toluene and the like. These solvents may be used alone or in combination of two or more.

Examples of methods for dispersing particles (for example, charge generating material) in the coating liquid for forming a charge generating layer include media dispersing machines such as ball mills, vibrating ball mills, attritors, sand mills, and horizontal sand mills, stirring machines, and ultrasonic dispersing machines. Medialess dispersion machines such as , roll mills, and high-pressure homogenizers are used. Examples of the high-pressure homogenizer include a collision method in which the dispersion liquid is dispersed by liquid-liquid collision or liquid-wall collision under high pressure, and a penetration method in which the dispersion is dispersed by penetrating fine channels under high pressure.
In addition, during this dispersion, it is effective to keep the average particle size of the charge generating material in the coating liquid for forming a charge generating layer to 0.5 μm or less, preferably 0.3 μm or less, and more preferably 0.15 μm or less. .

Examples of methods for applying the charge generation layer forming coating liquid onto the subbing layer (or onto the intermediate layer) include blade coating, wire bar coating, spray coating, dip coating, bead coating, and air knife coating. For example, conventional methods such as a coating method and a curtain coating method may be used.

The thickness of the charge generation layer is, for example, preferably set within a range of 0.1 μm or more and 5.0 μm or less, more preferably 0.2 μm or more and 2.0 μm or less.

(charge transport layer)
The charge transport layer is, for example, a layer containing a charge transport material and a binder resin. The charge transport layer may be a layer containing a polymeric charge transport material.

As charge transport materials, quinone compounds such as p-benzoquinone, chloranil, bromanil, and anthraquinone; tetracyanoquinodimethane compounds; fluorenone compounds such as 2,4,7-trinitrofluorenone; xanthone compounds; benzophenone compounds Examples include electron transporting compounds such as cyanovinyl compounds; ethylene compounds. Examples of the charge transporting material include hole transporting compounds such as triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted ethylene compounds, stilbene compounds, anthracene compounds, and hydrazone compounds. These charge transport materials may be used alone or in combination of two or more, but are not limited thereto.

As the charge transport material, from the viewpoint of charge mobility, a triarylamine derivative represented by the following structural formula (a-1) and a benzidine derivative represented by the following structural formula (a-2) are preferable.

In structural formula (a-1), Ar ^T1 , Ar ^T2 , and Ar ^T3 each independently represent a substituted or unsubstituted aryl group, -C ₆ H ₄ -C(R ^T4 )=C(R ^T5 )(R ^T6 ), or -C ₆ H ₄ -CH=CH-CH=C(R ^T7 )(R ^T8 ). R ^T4 , R ^T5 , R ^T6 , R ^T7 , and R ^T8 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group.
Examples of substituents for each of the above groups include a halogen atom, an alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms. Furthermore, examples of the substituents for each of the above groups include a substituted amino group substituted with an alkyl group having 1 or more and 3 or less carbon atoms.

In structural formula (a-2), R ^T91 and R ^T92 each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. ^RT101 , ^RT102 , ^RT111 and ^RT112 are each independently substituted with a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an alkyl group having 1 to 2 carbon atoms represents an amino group, a substituted or unsubstituted aryl group, -C(R ^T12 )=C(R ^T13 )(R ^T14 ), or -CH=CH-CH=C(R ^T15 )(R ^T16 ), R ^T12 , R ^T13 , R ^T14 , R ^T15 and R ^T16 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. Tm1, Tm2, Tn1 and Tn2 each independently represent an integer of 0 or more and 2 or less.
Examples of substituents for each of the above groups include a halogen atom, an alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms. Furthermore, examples of the substituents for each of the above groups include a substituted amino group substituted with an alkyl group having 1 or more and 3 or less carbon atoms.

Here, among the triarylamine derivative represented by the structural formula (a-1) and the benzidine derivative represented by the structural formula (a-2), in particular, "-C ₆ H ₄ -CH=CH-CH= Triarylamine derivatives having "C(R ^T7 )(R ^T8 )" and benzidine derivatives having "-CH=CH-CH=C(R ^T15 )(R ^T16 )" are preferred from the viewpoint of charge mobility.

As the polymeric charge transporting material, known materials having charge transporting properties such as poly-N-vinylcarbazole and polysilane are used. In particular, polyester-based polymeric charge transport materials are particularly preferred. Note that the polymer charge transport material may be used alone, or may be used in combination with a binder resin.

The binder resin used for the charge transport layer includes polycarbonate resin, polyester resin, polyarylate resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer, Vinylidene chloride-acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N -Vinyl carbazole, polysilane, etc. Among these, polycarbonate resin or polyarylate resin is suitable as the binder resin. These binder resins may be used alone or in combination of two or more.
Note that the blending ratio of the charge transport material and the binder resin is preferably from 10:1 to 1:5 in terms of mass ratio.

The charge transport layer may also contain other well-known additives.

There are no particular restrictions on the formation of the charge transport layer, and well-known formation methods may be used. , by heating if necessary.

Examples of solvents for preparing the coating solution for forming the charge transport layer include aromatic hydrocarbons such as benzene, toluene, xylene, and chlorobenzene; ketones such as acetone and 2-butanone; and methylene chloride, chloroform, and ethylene chloride. Halogenated aliphatic hydrocarbons; common organic solvents such as cyclic or linear ethers such as tetrahydrofuran and ethyl ether; These solvents may be used alone or in combination of two or more.

Application methods for applying the charge transport layer forming coating liquid onto the charge generation layer include blade coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating. Usual methods such as coating methods can be used.

The thickness of the charge transport layer is, for example, preferably set within a range of 5 μm or more and 50 μm or less, more preferably 10 μm or more and 30 μm or less.

(Inorganic protective layer)
The inorganic protective layer contains metal element M, oxygen O and hydrogen H.
Further, the inorganic protective layer includes a first region existing on the outer circumferential surface side of the inorganic protective layer and a second region existing on the inner circumferential surface side of the inorganic protective layer, and the MH bond of the first region is The ratio of the abundance of M-OH bonds to the abundance is R1 (OH/H), and the ratio of the abundance of M-OH bonds to the abundance of M-H bonds in the second region is R2 (OH/H). When, the following formula (1-1) and the following formula (2) are satisfied.
Formula (1-1): R1(OH/H)<1.0
Formula (2): R1(OH/H)<R2(OH/H)

The first region is a region where the absorption intensity of the peak derived from the M-OH bond calculated in "-Calculation of R1 (OH/H) and R2 (OH/H)-" described later is less than 5%. It is preferable that
The second region is a region where the absorption intensity of the peak derived from the M-OH bond calculated in "-Calculation of R1 (OH/H) and R2 (OH/H)-" described later is 5% or more. It is preferable that
The MH bond means a bond between a metal element M and hydrogen H.
The M--OH bond means a bond between the metal element M and a hydroxy group.

R1(OH/H) preferably satisfies the following formula (1-2), and more preferably satisfies the following formula (1-3).
Formula (1-2): R1(OH/H)<0.5
Formula (1-3): 0.01<R1(OH/H)<0.3

By setting R1(OH/H) to less than 0.5, the amount of M--OH bonds in the first region is reduced, the resistance of the photoreceptor surface is reduced, and the generation of charge flow is suppressed.
By setting R1(OH/H) to a value exceeding 0.01, the movement of charges in the thickness direction of the inorganic protective layer becomes less likely to be inhibited, and the function as a photoreceptor becomes less likely to be inhibited.

R1 (OH/H) and R2 (OH/H) preferably satisfy the following formula (3-1), more preferably satisfy the following formula (3-2), and satisfy the following formula (3-3). It is more preferable that the conditions are satisfied.
Formula (3-1): 0.3<R2(OH/H)-R1(OH/H)
Formula (3-2): 0.4<R2(OH/H)-R1(OH/H)<1.0
Formula (3-3): 0.5<R2(OH/H)-R1(OH/H)<0.8

By R1 (OH/H) and R2 (OH/H) satisfying formula (3-1), the proportion of M-OH bonds in the second region becomes the proportion of M-OH bonds in the first region. The amount is sufficiently increased compared to , and the movement of charges in the thickness direction of the inorganic protective layer is less likely to be inhibited, and the function as a photoreceptor is less likely to be inhibited.

- Calculation of R1 (OH/H) and R2 (OH/H) -
R1 (OH/H) and R2 (OH/H) are calculated from an infrared absorption spectrum measured by a reflection method using a Fourier transform infrared spectrophotometer (manufactured by Perkin Elmer, product name Spotlight 400).
The method of calculating R1 (OH/H) and R2 (OH/H) will be explained below.
- Calculation method of R1 (OH/H) First, the surface of the outer peripheral surface of the inorganic protective layer is measured with an infrared spectrophotometer to obtain an infrared absorption spectrum. Then, the absorption intensity of the peak derived from the M-H bond (1000 cm ^-1 when the metal element M is gallium) and the peak derived from the M-OH bond (3500 cm ^-1 when the metal element M is gallium) ) and calculate the absorption intensity. Then, divide the absorption intensity of the peak originating from the M-OH bond by the absorption intensity of the peak originating from the M-H bond (i.e., the absorption intensity of the peak originating from the M-OH bond ÷ the absorption intensity of the peak originating from the M-H bond). The value obtained from this (peak absorption intensity) is defined as R1 (OH/H).
- Calculation method of R2 (OH/H) Subsequently, the outer peripheral surface of the inorganic protective layer is etched. Etching is performed in the following steps.
・Etching method: Perform etching using ion sputtering method. A sample (electrophotographic photoreceptor) is set in an etching device, brought to a vacuum state, and then irradiated with argon ions to scrape off the surface of the sample.
The surface of the etched area is measured using an infrared spectrophotometer to obtain an infrared absorption spectrum. Then, the absorption intensity of the peak derived from the M--OH bond is calculated.
Repeat the above etching and calculation of the absorption intensity of the peak originating from the M-OH bond, and compare the areas where the absorption intensity of the peak originating from the M-OH bond has changed by 5% or more between the first region and the second region. Identify it as an interface.
After reaching the interface, the surface of the etched region is measured using an infrared spectrophotometer to obtain an infrared absorption spectrum. Then, the value obtained by dividing the absorption intensity of the peak derived from the M--OH bond by the absorption intensity of the peak derived from the M--H bond is defined as R2 (OH/H).

Here, R1 (OH/H) and R2 (OH/H) may be measured at the time of forming the inorganic protective layer. The procedure for measuring R1 (OH/H) and R2 (OH/H) during formation of the inorganic protective layer is as follows.
A measurement sample for the first region was prepared on the surface of a Si wafer (5 mm in length, 10 mm in width, and 400 μm in thickness; the same shall apply hereinafter) under the same film forming conditions as in forming the first region. do. Then, R1 (OH/H) is calculated using the same procedure as the calculation method for R1 (OH/H) above, except that the measurement sample is used as the measurement target.
Further, a sample for measurement of the first region is prepared on the surface of the Si wafer under the same film forming conditions as those used for forming the first region. Then, R2 (OH/H) is calculated using the same procedure as the calculation method for R2 (OH/H) above, except that the measurement sample is used as the measurement target.

Examples of the metal element M include Group 13 elements.
Group 13 elements include boron, aluminum, gallium, and indium.
Among these, from the viewpoint of suppressing the occurrence of image deletion in the photoreceptor, the metal element M is preferably a Group 13 element, and more preferably gallium.

By using gallium as the metal element M, the occurrence of image deletion is further suppressed.
The reason is assumed to be as follows.
Compared to other metal elements, gallium tends to be in a stable state with fewer atoms bonded to OH groups, and therefore tends to have a higher surface resistance than other elements.

The sum of the elemental ratios of metal element M, oxygen O, and hydrogen H to all elements contained in the inorganic protective layer is preferably 90% or more from the viewpoint of electrical properties and wear resistance of the inorganic protective layer in the photoreceptor. , 95% is more preferable, and 98% or more is still more preferable.

The inorganic protective layer may contain one or more elements selected from C, Si, Ge, and Sn in order to control the conductivity type, for example, in the case of n-type conductivity. Further, for example, in the case of p-type, it may contain one or more elements selected from N, Be, Mg, Ca, and Sr.

The thickness of the first region is preferably smaller than the thickness of the second region.
With this configuration, the movement of charges in the thickness direction of the inorganic protective layer is less likely to be inhibited, and the function as a photoreceptor is less likely to be inhibited.

The thickness of the first region relative to the thickness of the second region (thickness of the first region/thickness of the second region) is preferably 0.1 or more and 1.0 or less, and 0.1 to 1.0. It is more preferably 15 or more and 0.8 or less, and even more preferably 0.2 or more and 0.5 or less.
By setting the film thickness of the first region to be 0.1 or more with respect to the film thickness of the second region, the thickness of the first region where the amount of M-OH bonds is small increases, and the resistance of the surface of the photoreceptor increases. This is ensured to the extent that the occurrence of upward charge flow is suppressed.
In addition, by setting the thickness of the first region to 1.0 or less with respect to the thickness of the second region, the thickness of the second region, which has a low resistance, can reduce the charge in the thickness direction of the inorganic protective layer. Ensure that movement is not hindered.

The film thickness of the first region and the film thickness of the second region are measured using a surface roughness measuring device.
The procedure for measuring the film thickness in the first region and the film thickness in the second region is as follows.
The first area and the second area are separated by following the procedure described in ``How to calculate R2(OH/H)'' in ``-Calculation of R1(OH/H) and R2(OH/H)-'' above. After specifying the interface, the thickness of the sample etched to the interface is measured to determine the thickness of the second region. Then, the difference in the thickness of the second region is calculated from the thickness of the entire inorganic protective layer, and the calculated value is taken as the thickness of the first region.

The thickness of the inorganic protective layer is preferably 0.2 μm or more and 10.0 μm or less, and more preferably 0.4 μm or more and 5.0 μm or less, from the viewpoint of suppressing image deletion.

-Method for forming an inorganic protective layer-
Next, a method for forming the above-mentioned inorganic protective layer will be explained.
For forming the inorganic protective layer, a known vapor deposition method such as a plasma CVD (Chemical Vapor Deposition) method, an organometallic vapor phase epitaxy method, a molecular beam epitaxy method, vapor deposition, or sputtering is used.

FIG. 3 is a schematic diagram showing an example of a film forming apparatus used for forming the inorganic protective layer of the electrophotographic photoreceptor according to the present embodiment, and FIG. 3(A) shows a side view of the film forming apparatus. 3(B) represents a schematic sectional view of the film forming apparatus shown in FIG. 3(A) between A1 and A2. In FIG. 3, 210 is a film forming chamber, 211 is an exhaust port, 212 is a substrate rotation unit, 213 is a substrate support member, 214 is a substrate, 215 is a gas introduction pipe, and 216 is a gas introduced from the gas introduction pipe 215. A shower nozzle having an opening, 217 a plasma diffusion section, 218 a high frequency power supply section, 219 a flat plate electrode, 220 a gas introduction tube, and 221 a high frequency discharge tube section.

In the film forming apparatus shown in FIG. 3, an exhaust port 211 connected to a vacuum evacuation device (not shown) is provided at one end of the film forming chamber 210, and the side of the film forming chamber 210 where the exhaust port 211 is provided. On the opposite side, a plasma generation device including a high frequency power supply section 218, a flat plate electrode 219, and a high frequency discharge tube section 221 is provided.
This plasma generating device includes a high-frequency discharge tube section 221, a flat plate electrode 219 disposed inside the high-frequency discharge tube section 221 and whose discharge surface is provided on the exhaust port 211 side, and a flat plate electrode 219 disposed outside the high-frequency discharge tube section 221. It is composed of a high frequency power supply section 218 connected to the discharge surface of the electrode 219 and the opposite surface. Note that a gas introduction tube 220 for supplying gas into the high frequency discharge tube section 221 is connected to the high frequency discharge tube section 221, and the other end of the gas introduction tube 220 is connected to a first tube (not shown). connected to a gas supply.

Note that the plasma generator shown in FIG. 4 may be used instead of the plasma generator provided in the film forming apparatus shown in FIG. 3. FIG. 4 is a schematic diagram showing another example of the plasma generating device used in the film forming apparatus shown in FIG. 3, and is a side view of the plasma generating device. In FIG. 4, 222 represents a high frequency coil, 223 represents a quartz tube, and 220 is the same as that shown in FIG. This plasma generator consists of a quartz tube 223 and a high-frequency coil 222 provided along the outer peripheral surface of the quartz tube 223. One end of the quartz tube 223 is connected to a film forming chamber 210 (not shown in FIG. 4). It is connected. Furthermore, a gas introduction tube 220 for introducing gas into the quartz tube 223 is connected to the other end of the quartz tube 223 .

In FIG. 3, a rod-shaped shower nozzle 216 extending along the discharge surface is connected to the discharge surface side of the flat plate electrode 219. One end of the shower nozzle 216 is connected to a gas introduction pipe 215, and this gas The introduction pipe 215 is connected to a second gas supply source (not shown) provided outside the film forming chamber 210.
In addition, a substrate rotation unit 212 is provided in the film forming chamber 210, and a cylindrical substrate 214 is attached to a substrate support member such that the longitudinal direction of the shower nozzle 216 and the axial direction of the substrate 214 face each other. It is designed to be attached to the base body rotating part 212 via 213. During film formation, the base body 214 rotates in the circumferential direction as the base body rotating section 212 rotates. Note that, as the base 214, for example, a laminate in which the photosensitive layer is laminated in advance, a laminate in which the photosensitive layer is laminated up to the second region, or the like is used.

Formation of the inorganic protective layer is performed, for example, as follows.
First, oxygen gas (or helium (He) diluted oxygen gas), hydrogen (H ₂ ) gas, and if necessary helium (He) gas are introduced into the high frequency discharge tube section 221 from the gas introduction tube 220, and Radio waves of 13.56 MHz are supplied from the high frequency power supply section 218 to the flat plate electrode 219. At this time, the plasma diffusion section 217 is formed to spread radially from the discharge surface side of the flat plate electrode 219 toward the exhaust port 211 side. Here, the gas introduced from the gas introduction pipe 220 flows through the film forming chamber 210 from the flat electrode 219 side to the exhaust port 211 side. The flat plate electrode 219 may be surrounded by an earth shield.
Next, trimethyl gallium gas is introduced into the film forming chamber 210 through the gas introduction pipe 215 and the shower nozzle 216 located downstream of the flat plate electrode 219, which is an activation means, so that gallium and oxygen are formed on the surface of the substrate 214. A non-single-crystal film is formed.
As the base 214, for example, a laminate on which a photosensitive layer is formed is used.
Furthermore, when forming a film containing zinc as the second region, the gases introduced from the gas introduction pipe 215 include, for example, trimethylgallium gas and organic zinc gas (for example, dimethylzinc or diethylzinc gas). Zinc) gas is used. At this time, trimethyl gallium and organic zinc are introduced into the gas introduction pipe 215 as gases from separate containers.

The temperature of the surface of the substrate 214 during the formation of the inorganic protective layer is preferably 150° C. or lower, more preferably 100° C. or lower, particularly preferably 30° C. or higher and 100° C. or lower when a laminate having a photosensitive layer is used.
Even if the temperature of the surface of the substrate 214 is 150° C. or less at the beginning of film formation, if the temperature rises above 150° C. due to the influence of plasma, the photosensitive layer may be damaged by heat, so this effect should be taken into consideration. Preferably, the surface temperature of the substrate 214 is controlled.
Further, when an amorphous silicon photoreceptor is used, the temperature of the surface of the base 214 during the formation of the inorganic protective layer is, for example, 30° C. or more and 350° C. or less.
The temperature of the surface of the base 214 may be controlled by heating and/or cooling means (not shown in the figure), or may be allowed to rise naturally during discharge. When heating the base 214, a heater may be installed outside or inside the base 214. When cooling the base 214, a cooling gas or liquid may be circulated inside the base 214.
If it is desired to avoid an increase in the temperature of the surface of the base 214 due to discharge, it is effective to adjust the high-energy gas flow that hits the surface of the base 214. In this case, conditions such as gas flow rate, discharge output, and pressure are adjusted to achieve the required temperature.

Further, instead of trimethylgallium gas, an organometallic compound containing aluminum or a hydride such as diborane may be used, and two or more types of these may be mixed.
For example, in the initial stage of forming the inorganic protective layer, a film containing nitrogen and indium is formed on the substrate 214 by introducing trimethylindium into the film forming chamber 210 through the gas introduction pipe 215 and the shower nozzle 216. This film then absorbs ultraviolet rays that occur during continuous film formation and degrade the photosensitive layer. Therefore, damage to the photosensitive layer due to the generation of ultraviolet rays during film formation is suppressed.

Furthermore, a dopant may be added to the inorganic protective layer in order to control its conductivity type.
As for the method of doping dopants during film formation, SiH ₃ and SnH ₄ are used for n-type, and biscyclopentadienylmagnesium, dimethylcalcium, dimethylstrontium, etc. are used in gaseous state for p-type. . Further, in order to dope the dopant element into the inorganic protective 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 210 through the gas introduction pipe 215 and the shower nozzle 216, conductivity types such as n-type and p-type are introduced. Obtain an inorganic protective layer.

In the film forming apparatus described using FIGS. 3 and 4, active nitrogen or active hydrogen formed by discharge energy may be independently controlled by providing a plurality of activation devices, or may be formed by controlling nitrogen atoms such as NH ₃ independently. A gas containing hydrogen atoms at the same time may be used. Furthermore, _H2 may be added. Further, conditions may be used in which active hydrogen is generated freely from the organometallic compound.
By doing so, activated carbon atoms, gallium atoms, nitrogen atoms, hydrogen atoms, and the like exist in a controlled state on the surface of the base 214. The activated hydrogen atoms have the effect of desorbing hydrogen from hydrocarbon groups such as methyl groups and ethyl groups constituting the organometallic compound as molecules.
Therefore, a hard film (inorganic protective layer) that constitutes a three-dimensional bond is formed.

The plasma generation means of the film forming apparatus shown in FIGS. 3 and 4 uses a high frequency oscillation device, but is not limited to this. For example, a microwave oscillation device or an electrocyclotron resonance method is used. Alternatively, a helicon plasma type device may be used. Furthermore, in the case of a high frequency oscillation device, it may be of an inductive type or a capacitive type.
Furthermore, two or more types of these devices may be used in combination, or two or more of the same type of devices may be used. Although a high frequency oscillator is preferable to suppress the temperature rise on the surface of the base 214 due to plasma irradiation, a device for suppressing heat irradiation may be provided.

When using two or more different types of plasma generating devices (plasma generating means), it is preferable that discharges are generated at the same time under the same pressure. Further, a pressure difference may be provided between the region where the discharge occurs and the region where the film is formed (the part where the base body is installed). These devices may be arranged in series with the gas flow that is formed from the part where the gas is introduced to the part where it is discharged in the film forming apparatus, or both devices may be arranged in series with the gas flow that is formed from the part where the gas is introduced to the part where the gas is discharged. They may be arranged to face each other.

For example, when two types of plasma generation means are installed in series with respect to the gas flow, taking the film forming apparatus shown in FIG. It is used as a second plasma generator. In this case, for example, a high frequency voltage is applied to the shower nozzle 216 via the gas introduction pipe 215 to cause discharge in the film forming chamber 210 using the shower nozzle 216 as an electrode. Alternatively, instead of using the shower nozzle 216 as an electrode, a cylindrical electrode is provided between the base 214 and the flat electrode 219 in the film forming chamber 210, and this cylindrical electrode is used to cause a discharge within.
Furthermore, when using two different types of plasma generators 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 greatly changed, which can be used to control film quality. It is valid. Further, the discharge may be performed at near atmospheric pressure (70,000 Pa or more and 110,000 Pa or less). When performing discharge near atmospheric pressure, it is preferable to use He as the carrier gas.

In addition to the above-mentioned methods, normal organometallic vapor phase epitaxy and molecular beam epitaxy are also used to form the inorganic protective layer, but active nitrogen and/or Alternatively, using active hydrogen or active oxygen is effective for lowering the temperature. In this case, the nitrogen raw material used is a gas or liquid such as N ₂ , NH ₃ , NF ₃ , N ₂ H ₄ or methylhydrazine, which is vaporized or bubbled with a carrier gas. As the oxygen raw material, oxygen, H ₂ O, CO, CO ₂ , NO, N ₂ O, etc. are used.

The formation of the inorganic protective layer in this embodiment is carried out, for example, by installing a substrate 214 on which a photosensitive layer is formed in the film forming chamber 210, and introducing mixed gases having different compositions into the second region and the first region. form a continuous area.
Further, each region (or each layer) may be formed separately and independently.

Further, as the film forming conditions, for example, when discharging by high frequency discharge, in order to form a high quality film at a low temperature, the frequency is preferably in the range of 10 kHz or more and 50 MHz or less. Further, although the output depends on the size of the substrate, it is preferably in the range of 0.05 W/cm ² or more and 0.5 W/cm ^{2 or} less relative to the surface area of the substrate. The rotational speed of the substrate is preferably in the range of 10 rpm or more and 1000 rpm or less.
The film forming conditions for each region (or each layer) may be the same, but for example, the second region may be formed at a low temperature, so the output may be lower, and the first region may be formed at a higher output. good.

Here, in order to obtain the inorganic protective layer of the photoreceptor according to this embodiment, in order to remove atmospheric moisture adhering to the inside of the film forming apparatus in forming the inorganic protective layer, before starting film forming. It is preferable to flow oxygen gas into the film forming apparatus without evacuation. After the oxygen gas has flowed in, the film forming apparatus is evacuated when the internal pressure reaches atmospheric pressure, and then film forming is performed.

(Single layer type photosensitive layer)
The single-layer type photosensitive layer (charge generation/charge transport layer) is a layer containing, for example, a charge generation material, a charge transport material, and, if necessary, a binder resin and other well-known additives. Note that these materials are the same as those described for the charge generation layer and the charge transport layer.
The content of the charge generating material in the single-layer photosensitive layer is preferably 0.1% by mass or more and 10% by mass or less, preferably 0.8% by mass or more and 5% by mass or less based on the total solid content. . Further, the content of the charge transporting material in the single-layer type photosensitive layer is preferably 5% by mass or more and 50% by mass or less based on the total solid content.
The method for forming the single-layer type photosensitive layer is the same as the method for forming the charge generation layer and the charge transport layer.
The thickness of the single-layer type photosensitive layer is, for example, preferably 5 μm or more and 50 μm or less, preferably 10 μm or more and 40 μm or less.

<Image forming apparatus (and process cartridge)>
The image forming apparatus according to the present embodiment includes an electrophotographic photoreceptor, a charging device that charges the surface of the electrophotographic photoreceptor, and an electrostatic latent image forming device that forms an electrostatic latent image on the surface of the charged electrophotographic photoreceptor. a developing device that develops an electrostatic latent image formed on the surface of an electrophotographic photoreceptor with a developer containing toner to form a toner image, and a transfer device that transfers the toner image onto the surface of a recording medium; Equipped with. The electrophotographic photoreceptor according to the present embodiment is applied as the electrophotographic photoreceptor.

The image forming apparatus according to the present embodiment is an apparatus including a fixing device that fixes a toner image transferred to the surface of a recording medium; direct transfer that directly transfers a toner image formed on the surface of an electrophotographic photoreceptor to a recording medium. An intermediate transfer system that primarily transfers the toner image formed on the surface of an electrophotographic photoreceptor onto the surface of an intermediate transfer member, and secondarily transfers the toner image transferred to the surface of the intermediate transfer member onto the surface of a recording medium. An apparatus equipped with a cleaning device that cleans the surface of the electrophotographic photoreceptor after the toner image has been transferred and before charging; an apparatus that irradiates the surface of the electrophotographic photoreceptor with neutralizing light after the toner image has been transferred and before charging. Well-known image forming apparatuses such as an apparatus equipped with a static eliminator that eliminates static electricity by using a static eliminator and an apparatus equipped with an electrophotographic photoreceptor heating member for increasing the temperature of the electrophotographic photoreceptor and reducing its relative temperature are applied.

In the case of an intermediate transfer type device, the transfer device includes, for example, an intermediate transfer body on which a toner image is transferred, and a primary transfer body that primarily transfers a toner image formed on the surface of an electrophotographic photoreceptor onto the surface of the intermediate transfer body. A configuration including a transfer device and a secondary transfer device that secondarily transfers the toner image transferred to the surface of the intermediate transfer member to the surface of the recording medium is applied.

The image forming apparatus according to this embodiment may be either a dry developing type image forming apparatus or a wet developing type image forming apparatus (a developing type using a liquid developer).

In the image forming apparatus according to the present embodiment, for example, the portion including the electrophotographic photoreceptor may have a cartridge structure (process cartridge) that is detachable from the image forming apparatus. As the process cartridge, for example, a process cartridge including the electrophotographic photoreceptor according to the present embodiment is suitably used. In addition to the electrophotographic photoreceptor, the process cartridge may include, for example, at least one selected from the group consisting of a charging device, an electrostatic latent image forming device, a developing device, and a transfer device.

An example of an image forming apparatus according to this embodiment will be shown below, but the present invention is not limited thereto. Note that the main parts shown in the figure will be explained, and the explanation of the others will be omitted.

FIG. 5 is a schematic configuration diagram showing an example of an image forming apparatus according to this embodiment.
As shown in FIG. 5, the image forming apparatus 100 according to the present embodiment includes a process cartridge 300 including an electrophotographic photoreceptor 7, an exposure device 9 (an example of an electrostatic latent image forming device), and a transfer device 40 (primary (transfer device) and an intermediate transfer body 50. In the image forming apparatus 100, the exposure device 9 is arranged at a position where it can expose the electrophotographic photoreceptor 7 from the opening of the process cartridge 300, and the transfer device 40 exposes the electrophotographic photoreceptor 7 via the intermediate transfer member 50. The intermediate transfer body 50 is disposed at a position opposite to the electrophotographic photoreceptor 7 , and a portion of the intermediate transfer body 50 is disposed in contact with the electrophotographic photoreceptor 7 . Although not shown, it also includes a secondary transfer device that transfers the toner image transferred to the intermediate transfer member 50 onto a recording medium (for example, paper). Note that the intermediate transfer body 50, the transfer device 40 (primary transfer device), and the secondary transfer device (not shown) correspond to an example of a transfer device.

The process cartridge 300 in FIG. 5 integrates an electrophotographic photoreceptor 7, a charging device 8 (an example of a charging device), a developing device 11 (an example of a developing device), and a cleaning device 13 (an example of a cleaning device) in a housing. I support it. The cleaning device 13 includes a cleaning blade (an example of a cleaning member) 131, and the cleaning blade 131 is arranged so as to be in contact with the surface of the electrophotographic photoreceptor 7. Note that the cleaning member may be a conductive or insulating fibrous member instead of the cleaning blade 131, and may be used alone or in combination with the cleaning blade 131.

FIG. 5 shows, as an image forming apparatus, a fibrous member 132 (roll-shaped) that supplies the lubricant 14 to the surface of the electrophotographic photoreceptor 7, and a fibrous member 133 (flat brush-shaped) that assists in cleaning. Although an example is shown in which these are provided, these may be placed as necessary.

Each configuration of the image forming apparatus according to this embodiment will be described below.

-Charging device-
As the charging device 8, for example, a contact type charger using a conductive or semiconductive charging roller, a charging brush, a charging film, a charging rubber blade, a charging tube, etc. is used. In addition, chargers that are known per se, such as a non-contact type roller charger, a scorotron charger or a corotron charger that utilizes corona discharge, are also used.

-Exposure equipment-
Examples of the exposure device 9 include optical equipment that exposes the surface of the electrophotographic photoreceptor 7 with light such as semiconductor laser light, LED light, liquid crystal shutter light, etc. in a predetermined image manner. The wavelength of the light source is within the spectral sensitivity range of the electrophotographic photoreceptor. The mainstream wavelength of semiconductor lasers is near-infrared, which has an oscillation wavelength around 780 nm. However, the wavelength is not limited to this, and a laser having an oscillation wavelength of 600 nm or more or a blue laser having an oscillation wavelength of 400 nm or more and 450 nm or less may also be used. Furthermore, for color image formation, a surface-emitting laser light source capable of outputting multiple beams is also effective.

-Developing device-
As the developing device 11, for example, a general developing device that performs development by contacting or non-contacting the developer can be mentioned. The developing device 11 is not particularly limited as long as it has the above-mentioned functions, and is selected depending on the purpose. For example, a known developing device having a function of attaching a one-component developer or a two-component developer to the electrophotographic photoreceptor 7 using a brush, a roller, or the like can be used. Among these, those using a developing roller holding developer on its surface are preferred.

The developer used in the developing device 11 may be a one-component developer containing only toner, or a two-component developer containing toner and a carrier. Further, the developer may be magnetic or non-magnetic. As these developers, well-known ones can be used.

-Cleaning device-
As the cleaning device 13, a cleaning blade type device including a cleaning blade 131 is used.
In addition to the cleaning blade method, a fur brush cleaning method and a simultaneous development cleaning method may be employed.

-Transfer device-
As the transfer device 40, for example, a contact type transfer charger using a belt, a roller, a film, a rubber blade, etc., a scorotron transfer charger or a corotron transfer charger using corona discharge, and other known transfer chargers are used. Can be mentioned.

-Intermediate transfer body-
As the intermediate transfer member 50, a belt-shaped member (intermediate transfer belt) containing semiconductive polyimide, polyamideimide, polycarbonate, polyarylate, polyester, rubber, or the like is used. Moreover, as for the form of the intermediate transfer member, a drum-like member may be used instead of a belt-like member.

FIG. 6 is a schematic configuration diagram showing another example of the image forming apparatus according to this embodiment.
The image forming apparatus 120 shown in FIG. 6 is a tandem multicolor image forming apparatus equipped with four process cartridges 300. In the image forming apparatus 120, four process cartridges 300 are arranged in parallel on the intermediate transfer member 50, and one electrophotographic photoreceptor is used for each color. Note that the image forming apparatus 120 has the same configuration as the image forming apparatus 100 except that it is of a tandem type.

Examples will be described below, but the present invention is not limited to these examples in any way. In the following description, all "parts" and "%" are based on mass unless otherwise specified.

<Example 1>
(Preparation of electrophotographic photoreceptor)
First, an undercoat layer, a charge generation layer, a charge transport layer, and an inorganic protective layer were laminated in this order on an aluminum (Al) substrate by the procedure described below.

- Formation of subbing layer -
20 parts by mass of a zirconium compound (trade name: Organotix ZC540 manufactured by Matsumoto Pharmaceutical Co., Ltd.), 2.5 parts by mass of a silane compound (trade name: A1100 manufactured by Nippon Unicar Co., Ltd.), polyvinyl butyral resin (trade name: S-LEC BM- manufactured by Sekisui Chemical Co., Ltd.) S) A solution obtained by stirring and mixing 10 parts by mass and 45 parts by mass of butanol was applied to the surface of an Al substrate with an outer diameter of 84 mm, and heated and dried at 150°C for 10 minutes to form a sublayer with a layer thickness of 1.0 μm. formed a layer.

-Formation of charge generation layer-
Next, a mixture obtained by mixing 1 part by mass of chlorogallium phthalocyanine as a charge-generating material with 1 part by mass of polyvinyl butyral (trade name: S-LEC BM-S manufactured by Sekisui Chemical Co., Ltd.) and 100 parts by mass of n-butyl acetate was used. This was dispersed together with glass beads in a paint shaker for 1 hour to obtain a dispersion for forming a charge generation layer.
This dispersion was applied onto the undercoat layer by a dipping method, and then dried at 100° C. for 10 minutes to form a charge generation layer with a layer thickness of 0.15 μm.

-Formation of charge transport layer-
Next, 2 parts by mass of a compound represented by the following structural formula (1), 3 parts by mass of a polymer compound (viscosity average molecular weight: 39000) whose repeating unit is represented by the following structural formula (2), and 20 parts by mass of chlorobenzene. A coating liquid for forming a charge transport layer was obtained by dissolving the mixture in parts by mass.

This coating solution was applied onto the charge generation layer by a dipping method and heated at 110°C for 40 minutes to form a charge transport layer with a layer thickness of 20 μm. A laminate was obtained in which the layers were laminated in this order.

- Formation of inorganic protective layer -
- Formation of second region The inorganic protective layer was formed on the surface of the laminate using a film forming apparatus having the configuration shown in FIG.
First, the laminate was placed on the substrate support member 213 in the film forming chamber 210 of the film forming apparatus, and the inside of the film forming chamber 210 was evacuated through the exhaust port 211 until the pressure reached 0.1 Pa.
Next, 20% oxygen gas diluted with He (flow rate 22.5 sccm) and H ₂ gas (flow rate 500 sccm) were introduced from the gas introduction tube 220 into the high frequency discharge tube section 221 in which the flat plate electrode 219 with a diameter of 85 mm was provided. The high frequency power supply section 218 and the matching circuit (not shown in FIG. 3) output a 13.56 MHz radio wave (hereinafter, the output of the radio wave is also referred to as "high frequency power") and set it to 500 W, and the tuner performed matching. Discharge was performed from the flat plate electrode 219. The reflected wave at this time was 0W.
Next, trimethyl gallium gas (flow rate 7.5 sccm) was introduced into the plasma diffusion section 217 in the film forming chamber 210 from the shower nozzle 216 via the gas introduction pipe 215. At this time, the reaction pressure inside the film forming chamber 210 was 50 Pa as measured by a Baratron vacuum gauge.
In this state, a film was formed for 450 minutes while rotating the laminate at a speed of 500 rpm to form a second region with a layer thickness of 5.0 μm on the surface of the charge transport layer of the laminate.

・Formation of the first region Next, after stopping the high-frequency discharge and changing to He diluted 20% oxygen gas (flow rate 7.5 sccm), H ₂ gas (flow rate 500 sccm), and trimethyl gallium gas (flow rate 7.5 sccm) Then, high frequency discharge was started again with high frequency power of 500W.
In this state, a film was formed for 115 minutes while rotating the laminate in which the second region was formed at a speed of 500 rpm, and a first region having a layer thickness of 1.0 μm was formed on the second region.

Through the above steps, a photoreceptor was obtained which had a subbing layer, a charge generation layer, a charge transport layer, and an inorganic protective layer in this order on an aluminum (Al) substrate.

<Examples 2 to 12, Comparative Examples 1 to 3>
In -Formation of inorganic protective layer-, a photoreceptor was obtained in the same manner as in Example 1, except that the film-forming conditions were changed according to Table 1.
In addition, in Example 7, triethylaluminum gas was used instead of trimethylgallium gas in -formation of the inorganic protective layer. In Table 1, "*" is attached to the numerical value of the trimethylgallium gas flow rate in Example 7, which indicates that it is the flow rate of triethylaluminum gas.

<Image quality evaluation>
The electrophotographic photoreceptors obtained in each Example and each Comparative Example were attached to an image forming apparatus (DocuCentre-V C7775, manufactured by Fujifilm Business Innovation Co., Ltd.), and the image density was determined under an environment of a temperature of 28° C. and a humidity of 85% RH. (Area Coverage) After outputting 5000 sheets of 5% chart images continuously on A4 paper, leaving them in the same environment for 14 hours, and after 14 hours, outputting 100 sheets of full-scale halftone images with image density of 40%, Image deletion from the 1st to 10th, 50th, and 100th images outputted after being left unused was confirmed.
The evaluation criteria were as follows, and the results are shown in Table 2.
A: The dots of the first image output after being left undisturbed are not disturbed.
B: The image dots on the first output sheet after being left unused are disordered, but the dot irregularities are recovered by the second to tenth output sheets after being left unused. (It recovers quickly, so there is no problem with the image quality)
C: The dots are disordered on the 10th output after being left unused, but the dot disorder is recovered by the 50th output after being left unused.
D: Dots are distorted even after outputting 50 sheets after being left unused, and dots are still slightly irregular even after outputting 100 sheets after being left unused, or dots are slightly disrupted even when outputting 5000 consecutive sheets before being left unused. .

From the above results, it can be seen that the photoreceptor of this example suppresses the occurrence of image deletion.

(((1))) having a conductive substrate, a photosensitive layer, and an inorganic protective layer containing a metal element M, oxygen O, and hydrogen H in this order,
The inorganic protective layer includes a first region located on the outer peripheral surface side of the inorganic protective layer and a second region located on the inner peripheral surface side of the inorganic protective layer,
The ratio of the abundance of M-OH bonds to the abundance of M-H bonds in the first region is R1 (OH/H), and the ratio of the abundance of M-OH bonds to the abundance of M-H bonds in the second region is R1 (OH/H). An electrophotographic photoreceptor that satisfies the following formula (1-1) and the following formula (2), where the ratio of the abundance of is R2 (OH/H).
Formula (1-1): R1(OH/H)<1.0
Formula (2): R1(OH/H)<R2(OH/H)
(((2))) The electrophotographic photoreceptor according to (((1))), which satisfies the following formula (3-1).
Formula (3-1): 0.3<R2(OH/H)-R1(OH/H)
(((3))) The electrophotographic photoreceptor according to ((2)), which satisfies the following formula (1-2).
Formula (1-2): R1(OH/H)<0.5
(((4))) The electrophotographic photoreceptor according to any one of (((1))) to (((3))), wherein the metal element M is gallium.
(((5))) The film thickness of the first region is smaller than the film thickness of the second region (((1))) to (((4))). Electrophotographic photoreceptor.
(((6))) The thickness of the first region relative to the thickness of the second region (thickness of the first region/thickness of the second region) is 0.1 or more and 1.0 or more. The electrophotographic photoreceptor described in ((5)) below.
(((7))) An electrophotographic photoreceptor according to any one of ((1)) to ((6))),
A process cartridge that can be attached to and removed from an image forming apparatus.
(((8))) (((1))) to (((6)));
a charging device that charges the surface of the electrophotographic photoreceptor;
an electrostatic latent image forming device that forms an electrostatic latent image on the surface of the charged electrophotographic photoreceptor;
a developing device that develops the electrostatic latent image formed on the surface of the electrophotographic photoreceptor to form a toner image using a developer containing toner;
a transfer device that transfers the toner image onto the surface of a recording medium;
An image forming apparatus comprising:
According to the invention according to ((1))), in the electrophotographic photoreceptor having a conductive substrate, a photosensitive layer, and an inorganic protective layer containing a metal element M, oxygen O, and hydrogen H in this order, In an electrophotographic photoreceptor in which the inorganic protective layer includes a first region located on the outer peripheral surface side of the inorganic protective layer and a second region located on the inner peripheral surface side of the inorganic protective layer, the first region R1 (OH/H) is the ratio of the abundance of M-OH bonds to the abundance of M-H bonds in the second region, and the ratio of the abundance of M-OH bonds to the abundance of M-H bonds in the second region. When R2(OH/H), an electrophotographic photoreceptor is provided that suppresses the occurrence of image deletion compared to the case where the formula (1-1) or the formula (2) is not satisfied.
According to the invention according to ((2))), an electrophotographic photoreceptor is provided that suppresses the occurrence of image deletion compared to a case where formula (3-1) is not satisfied.
According to the invention according to ((3))), an electrophotographic photoreceptor is provided that suppresses the occurrence of image deletion compared to a case where formula (1-2) is not satisfied.
According to the invention according to ((4))), an electrophotographic photoreceptor is provided that suppresses the occurrence of image deletion compared to a case where the metal element M is aluminum.
According to the invention according to ((5))), electrophotographic sensitization that suppresses the occurrence of image deletion compared to a case where the film thickness of the first region is larger than the film thickness of the second region. The body is provided.

According to the invention according to ((6))), the thickness of the first region (thickness of the first region/thickness of the second region) is greater than the thickness of the second region. An electrophotographic photoreceptor is provided that suppresses the occurrence of image deletion compared to cases where the ratio is less than 0.1 or more than 1.0.
According to the invention according to (((7))) or (((8))), the conductive substrate, the photosensitive layer, and the inorganic protective layer containing the metal element M, oxygen O, and hydrogen H are arranged in this order. , wherein the inorganic protective layer includes a first region located on the outer peripheral surface side of the inorganic protective layer and a second region located on the inner peripheral surface side of the inorganic protective layer. The ratio of the abundance of M-OH bonds to the abundance of M-H bonds in the first region is R1 (OH/H), and the ratio of the abundance of M-OH bonds to the abundance of M-H bonds in the second region is R1 (OH/H). Electrophotography that suppresses the occurrence of image deletion compared to the case where an electrophotographic photoreceptor that does not satisfy formula (1-1) or formula (2) is provided, when the ratio of abundance is R2 (OH/H) A process cartridge or an image forming apparatus including a photoreceptor is provided.

101 subbing layer, 102 charge generation layer, 103 charge transport layer, 104 conductive substrate, 105 photosensitive layer, 106 inorganic protective layer, 107A, 107B electrophotographic photoreceptor (photoreceptor), 7 electrophotographic photoreceptor, 8 charging device , 9 exposure device, 11 developing device, 13 cleaning device, 14 lubricant, 40 transfer device, 50 intermediate transfer body, 100 image forming device, 120 image forming device, 131 cleaning blade, 132 fibrous member (roll shape), 133 Fibrous member (flat brush type), 300 process cartridge

Claims (8)

A conductive substrate, a photosensitive layer, and an inorganic protective layer containing a metal element M, oxygen O and hydrogen H, in this order,
The inorganic protective layer includes a first region located on the outer peripheral surface side of the inorganic protective layer and a second region located on the inner peripheral surface side of the inorganic protective layer,
The ratio of the abundance of M-OH bonds to the abundance of M-H bonds in the first region is R1 (OH/H), and the ratio of the abundance of M-OH bonds to the abundance of M-H bonds in the second region is R1 (OH/H). An electrophotographic photoreceptor that satisfies the following formula (1-1) and the following formula (2), where the ratio of the abundance of is R2 (OH/H).
Formula (1-1): R1(OH/H)<1.0
Formula (2): R1(OH/H)<R2(OH/H) The electrophotographic photoreceptor according to claim 1, which satisfies the following formula (3-1).
Formula (3-1): 0.3<R2(OH/H)-R1(OH/H) The electrophotographic photoreceptor according to claim 2, which satisfies the following formula (1-2).
Formula (1-2): R1(OH/H)<0.5 The electrophotographic photoreceptor according to claim 1, wherein the metal element M is gallium. The electrophotographic photoreceptor according to claim 1, wherein the first region has a smaller thickness than the second region. According to claim 5, the thickness of the first region (thickness of the first region/thickness of the second region) with respect to the thickness of the second region is 0.1 or more and 1.0 or less. The electrophotographic photoreceptor described above. An electrophotographic photoreceptor according to any one of claims 1 to 6,
A process cartridge that can be attached to and removed from an image forming apparatus. The electrophotographic photoreceptor according to any one of claims 1 to 6,
a charging device that charges the surface of the electrophotographic photoreceptor;
an electrostatic latent image forming device that forms an electrostatic latent image on the surface of the charged electrophotographic photoreceptor;
a developing device that develops the electrostatic latent image formed on the surface of the electrophotographic photoreceptor to form a toner image using a developer containing toner;
a transfer device that transfers the toner image onto the surface of a recording medium;
An image forming apparatus comprising: