JP7353155B2 - Electrophotographic photoreceptors, process cartridges, and electrophotographic devices - Google Patents

Description

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

The electrophotographic photoreceptors installed in electrophotographic devices include organic electrophotographic photoreceptors (hereinafter referred to as "electrophotographic photoreceptors") that contain organic photoconductive substances (charge-generating substances), and have been extensively studied. has been done. In recent years, with the aim of extending the lifespan and improving image quality of electrophotographic photoreceptors, there has been a demand for electrophotographic photoreceptors to have mechanical durability (wear resistance) and less fluctuation in electrical properties due to long-term use.
In Patent Document 1, by having a polymer obtained by polymerizing a charge transporting substance having a polymerizable functional group in the outermost layer of an electrophotographic photoreceptor, the mechanical durability of the electrophotographic photoreceptor can be improved and electricity can be improved. A method for stabilizing the properties is described.

Japanese Patent Application Publication No. 2000-066425

Among charge-transporting substances having a polymerizable functional group, those containing triphenylamine have excellent charge-transporting properties and are resistant to chemical changes such as molecular chain cleavage and oxidation that occur during long-term image formation. This makes it difficult for image defects to occur due to long-term use. However, triphenylamine has a small structure as a substance having charge transport properties. For this reason, when a triphenylamine polymer having a polymerizable functional group is used in the outermost layer of an electrophotographic photoreceptor, large depletions are likely to occur in the surface layer film, and water permeates from the depletions in the surface layer to the photosensitive layer. It's easy to do.

According to studies conducted by the present inventors, although the electrophotographic photoreceptor described in Patent Document 1 has mechanical durability and good electrical properties, it is resistant to dew condensation that occurs when the environment changes rapidly. However, there was a problem in that recovery performance was sometimes unfavorable.
Therefore, an object of the present invention is to provide an electrophotographic photoreceptor having mechanical durability and dew condensation recovery property, which has a support and a photosensitive layer formed on the support. It is in. Another object of the present invention is to provide a process cartridge and an electrophotographic apparatus having the electrophotographic photoreceptor.

The above object is achieved by the present invention as follows. That is, the electrophotographic photoreceptor according to the present invention has a support and a photosensitive layer as a surface layer, or has a support, a photosensitive layer, and a protective layer as a surface layer in this order. A photographic photoreceptor, wherein the surface layer comprises a hole-transporting compound represented by the following formula (2-7) , a compound represented by the following formula ( 1-2 ), and a compound represented by the following formula (5-3). It is characterized by containing a polymer of a composition containing the compound represented by.

Another object of the present invention is to integrally support the electrophotographic photoreceptor and at least one means selected from the group consisting of charging means, developing means, transfer means , and cleaning means, and to An object of the present invention is to provide a process cartridge that can be freely attached to and detached from a main body.
Another object of the present invention is to provide an electrophotographic apparatus having the electrophotographic photoreceptor , charging means, exposure means, developing means , and transfer means .

According to the present invention, an electrophotographic photoreceptor having a support and a photosensitive layer provided on the support has mechanical durability and is resilient to dew condensation that occurs due to rapid changes in temperature and humidity. An improved electrophotographic photoreceptor can be provided. Further, according to the present invention, it is possible to provide a process cartridge and an electrophotographic apparatus having the electrophotographic photoreceptor.

1 is a diagram showing an example of a layer structure of an electrophotographic photoreceptor of the present invention. 1 is a diagram showing an example of a schematic configuration of an electrophotographic apparatus including a process cartridge having an electrophotographic photoreceptor according to the present invention. FIG. 2 is a diagram showing a press-contact shape transfer processing device used in Examples and Comparative Examples of the present invention. FIG. 3 is a diagram showing molds used in Examples and Comparative Examples of the present invention.

Hereinafter, the present invention will be described in detail by citing preferred embodiments.
In the electrophotographic photoreceptor according to one embodiment of the present invention, the surface layer includes a copolymer of a hole transporting compound having two or more chain-polymerizable functional groups and a compound represented by the following formula (1). It is characterized by containing.

(In formula (1), R ¹¹ and R ¹² each independently represent an alkyl group having 1 to 4 carbon atoms, a phenyl group having a substituent, or an unsubstituted phenyl group. The above-mentioned substituent is an alkyl group having 4 or less carbon atoms. R ¹¹ and R ¹² may be bonded to each other to form a ring. R ¹³ represents an alkyl group having 1 or more and 4 or less carbon atoms. R ¹⁴ and R ¹⁵ each independently represent an alkylene group having 1 to 4 carbon atoms. R ¹⁶ and R ¹⁷ each independently represent a hydroxy group or a (meth)acryloyloxy group. R ¹⁶ and Either one of R ¹⁷ represents a hydroxy group.)
The present inventors speculate that the reason why the effects of the present invention are manifested by having the above-mentioned characteristics is as follows.

When the electrophotographic photoreceptor is exposed to rapid temperature changes, dew condensation occurs on the electrophotographic photoreceptor. In order to recover from dew condensation, it is necessary to remove moisture on the electrophotographic photoreceptor. It is speculated that by making the surface layer of the electrophotographic photoreceptor hydrophilic, water generated by condensation changes into a thin film and evaporates more easily. The compound represented by the formula (1) has a moderately small molecular weight, polarity, and a cyclic structure containing oxygen, so it has high hydrophilicity. Furthermore, since the terminal of the formula (1) has an OH group on one side, it has better hydrophilicity. Since the other end has a chain polymerizable functional group, it becomes a copolymer with a hole transporting compound and is uniformly dispersed in the surface layer. Since the surface layer is more hydrophilic than a surface layer made of only a hole-transporting compound, moisture when condensation forms becomes a film and the speed of evaporation is improved. It is thought that this improves dew condensation recovery.
Specific examples of the compound represented by the formula (1) (Exemplary Compounds 1-1 to 1-21) are listed below, but the present invention is not limited thereto.

The content mass of the compound represented by the formula (1) in the surface layer is determined by the composition containing a hole transporting compound having two or more chain polymerizable functional groups and a compound represented by the following formula (1). It is preferably 20% by mass or less based on the total mass of.
If the contained mass exceeds 20% by mass with respect to the total mass, the dew condensation recovery property will be good, but the potential fluctuation itself will become large during repeated use. Therefore, within this range, both dew condensation recovery and suppression of potential fluctuations during repeated use can be achieved at a high level. More preferably, it is 10% by mass or less.

Furthermore, it is preferable for the surface layer of the electrophotographic photoreceptor to contain a compound represented by the following formula (2) or the following formula (3) in order to suppress potential fluctuations during repeated use. The present inventors speculate that the reason is as follows. The compound represented by the following formula (2) has a fluorene structure. While the fluorene structure has high planarity, only the carbon atom located at the 9-position of the fluorene structure is a carbon atom that forms an sp3 hybrid orbital, and the carbon atom is located in a direction different from the plane formed by the three condensed molecules. To position. It is thought that the positional relationship results in a structure that does not easily inhibit hole transport properties. Therefore, by improving the hole transport properties, potential fluctuations during repeated use can be suppressed.

(In formula (2), R ²¹ and R ²² each independently represent an alkyl group having 2 to 8 carbon atoms. R ²³ and R ²⁴ each independently represent a hydrogen atom or a carbon number of 4 or less R ²⁵ and R ²⁷ each independently represent an alkylene group having 3 or more and 6 or less carbon atoms. R ²⁶ and R ²⁸ each independently represent a hydrogen atom or a methyl group. )

Specific examples of the compound represented by the formula (2) (Exemplary Compounds 2-1 to 2-26) are listed below, but the present invention is not limited thereto.

Typical synthesis examples of the hole-transporting compound used in the present invention are shown below.
Typical synthesis examples of the hole-transporting compound used in the present invention are shown below.

<Synthesis example>
A synthesis example of a hole-transporting compound having a difunctional polymerizable acrylic group shown in Exemplary Compound Nos. 2-7 is shown below.

A triarylamine compound was synthesized using an iodo compound and an amine compound shown in reaction formula (1). In a reaction container, 94.5 parts of the iodo compound, 34.5 parts of the amine compound in the formula, and 80 parts of o-dichlorobenzene were mixed, and 26.9 parts of potassium carbonate and 16.6 parts of copper powder were added. The reaction was carried out at an internal temperature of about 210°C. The mixture was stirred and reacted for about 24 hours. After the reaction, filtration, toluene washing, and concentration were performed to obtain a crude product.

Subsequently, the resulting intermediate was hydrolyzed to convert the acetate to a hydroxyl group. 100 parts of tetrahydrofuran, 100 parts of methanol, and 70 parts of a 24% aqueous sodium hydroxide solution were mixed, heated to an internal temperature of 60°C, stirred, and reacted for 1 hour to perform hydrolysis. After the reaction, the reaction mixture was extracted with ethyl acetate, and the organic layer was washed with water, brine, dehydrated, and concentrated. Purification by silica gel chromatography provided the dihydroxy intermediate. Yield: 36.9 parts, yield (2 steps): 53.2%

36.5 parts of the dihydroxy intermediate obtained by the above reaction, 365 parts of toluene, and 0.7 parts of 4-methoxyphenol were mixed, and 11.8 parts of acrylic acid was charged into a reaction vessel. 1.3 parts of p-toluenesulfonic acid monohydrate was added and heated under reflux conditions at 112°C for 6 hours to carry out an acrylation reaction.
After the reaction, the mixture was cooled, neutralized by adding a 10% aqueous sodium hydroxide solution, and extracted with ethyl acetate. A crude product was obtained by washing with water, dehydration, and concentration.

Subsequently, the crude product was purified by silica gel column chromatography to obtain a hole transporting compound having a polymerizable functional group. Yield: 39.5 parts, yield 63.0%
Furthermore, a varnish was obtained by adjusting the solvent type and amount of the obtained hole-transporting compound. Similarly, other hole transporting compounds represented by the above formula (2) can be synthesized.
It is also preferable to contain a compound represented by the following formula (3) instead of the compound represented by the formula (2). In this case, the denseness of the membrane is improved by increasing the polymerization reaction rate, and environmental fluctuations can be suppressed.

(In formula (3), A represents a hole transporting group, ^P1 represents a monovalent functional group represented by the following formula (4), and a represents an integer from 1 to 4. a is 2 or more. , each P ¹ may be the same or different.The hydrogen adduct in which the bonding site of A with P ¹ is replaced with a hydrogen atom is represented by the following formula (5) or the following formula (6) is shown.)

(In formula (4), n represents an integer of 1 or 2, and X is selected from the group consisting of an alkylene group, -C(=O)-, -N(L)-, -S-, and -O- This represents an (n+1)-valent linking group formed by combining two or more selected types.L represents a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group.)

(In formula (5), R ⁵¹ , R ⁵² and R ⁵³ represent a phenyl group, a biphenyl group, or a fluorenyl group which may have an alkyl group having 1 to 6 carbon atoms as a substituent. Also, R ⁵¹ , ^R52 and ^R53 may be the same or different.)

(In formula (6), R ⁶¹ , R ⁶² , R ⁶³ and R ⁶⁴ represent a phenyl group which may have an alkyl group having 1 to 6 carbon atoms as a substituent. Also, R ⁶¹ , R ⁶² , R ⁶³ and R ⁶⁴ may be the same or different.)
Specific examples of the compound represented by the above formula (3) (Exemplary Compounds 3-1 to 3-4) are listed below, but the present invention is not limited thereto.

It is also preferable to contain a compound represented by the following formula (7) instead of the compound represented by the formula (2) or the formula (3). In this case, since the molecular volume is small, the denseness of the membrane is improved and environmental fluctuations can be suppressed.

(In formula (7), R ⁷¹ , R ⁷² and R ⁷³ each independently represent a substituted or unsubstituted phenyl group. At least two of R ⁷¹ , R ⁷² and R ⁷³ are represented by the following formula (8)) The substituent of the substituted phenyl group is an alkyl group, an alkoxy group, or a group represented by the following formula (8).)

(In formula (8), R ⁸¹ represents a hydrogen atom or a methyl group, and R ⁸² represents an alkylene group having 1 to 6 carbon atoms. n represents 0 or 1.)
Specific examples of the compound represented by the formula (7) (Exemplary Compounds 4-1 to 4-10) are listed below, but the present invention is not limited thereto.

Further, it is preferable that the protective layer of the electrophotographic photoreceptor contains a compound represented by the following formula (9) in order to suppress the environmental dependence of electrical properties. The present inventors speculate that the reason is as follows. Since the compound represented by formula (9) has an appropriate molecular weight and size, it improves the density of the membrane containing the hole-transporting compound and prevents moisture from entering the membrane from the environment. It is assumed that this has the effect of suppressing intrusion, etc. Therefore, in the present invention, by combining a hole-transporting compound and a compound represented by formula (1) above, the hydrophilicity of the membrane is improved, and at the same time, the compactness is also improved, moisture permeation in the surface layer is suppressed, and the environment is It is thought that fluctuations can be suppressed.

(In formula (9), R ⁹¹ and R ⁹² each independently represent a hydrogen atom or a methyl group. R ⁹³ and R ⁹⁴ each independently represent an alkyl group having 1 to 4 carbon atoms, or , represents a phenyl group having a substituent or an unsubstituted phenyl group. The substituent that the phenyl group has is an alkyl group having 4 or less carbon atoms. At least one of R ⁹³ and R ⁹⁴ has 2 carbon atoms. (Indicates the above alkyl group.)
The mass content of the compound represented by the formula (9) in the composition is preferably 0.1 times or more and 1.0 times or less with respect to the mass content of the hole transporting compound. .
If the mass content of the compound represented by formula (9) is less than 0.1 times, the effects of hydrophilicity and compactness cannot be obtained and environmental fluctuations cannot be suppressed. However, if it exceeds 1.0 times, the ratio of the hole transporting compound decreases, resulting in worsening of potential fluctuations regardless of environmental changes.
Specific examples of the compound represented by the formula (9) (Exemplary Compounds 5-1 to 5-20) are listed below, but the present invention is not limited thereto.

Among these, Exemplified Compounds 5-1, 5-2, and 5-3 are particularly preferred from the viewpoint of excellent environmental dependence of electrical properties.

<Synthesis example>
An example of synthesis of a bifunctional polymerizable acrylic group compound represented by the above formula (5-3) will be shown.

50 parts of 2-methylvaleraldehyde, 40.5 parts of 37% formaldehyde, and 8.5 parts of benzyltrimethylammonium hydroxide (40% aqueous solution) were mixed in an autoclave. The pressure was increased to 0.5 MPa with nitrogen, and the mixture was stirred at 90° C. for 1 hour. After the reaction was completed, the reaction solution was cooled to room temperature and separated. It was washed with water and concentrated to obtain about 50 parts of a colorless liquid.

50 parts of the colorless liquid, 52 parts of trimethylolpropane, and 1 part of p-toluenesulfonic acid were mixed. Stir overnight at room temperature. After the reaction was completed, the reaction product was purified by column chromatography (using silica gel, mobile phase: ethyl acetate) to obtain about 30 parts of a colorless oil.

The above colorless oil was subjected to dehydration condensation with acrylic acid using chloroform as a solvent, triethylamine as a catalyst, and dicyclohexylcarbodiimide as a dehydration condensation agent. The filtrate of the reaction product was concentrated and purified by column chromatography (using silica gel, mobile phase: n-hexane/ethyl acetate = 4/1) to obtain a colorless liquid. It was adjusted by adding 100 ppm of 4-methoxyphenol as a polymerization inhibitor.
Similarly, other polymerizable compounds represented by the above formula (9) can be synthesized.

[Electrophotographic photoreceptor]
An electrophotographic photoreceptor according to one embodiment of the present invention is characterized by having a support and a photosensitive layer in this order, or having a support, a photosensitive layer, and a protective layer in this order. When there is no protective layer, the photosensitive layer becomes the surface layer, and when there is a protective layer, the protective layer becomes the surface layer.
A method for manufacturing the electrophotographic photoreceptor of the present invention includes a method of preparing a coating solution for each layer, which will be described later, and applying the coating solution to the desired layers in order, followed by drying. At this time, examples of methods for applying the coating liquid include dip coating, spray coating, inkjet coating, roll coating, die coating, blade coating, curtain coating, wire bar coating, ring coating, and the like. Among these, dip coating is preferred from the viewpoint of being able to obtain excellent efficiency and productivity.
Each layer will be explained below.

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

<Conductive layer>
In the present invention, a conductive layer may be provided on the support. By providing a conductive layer, it is possible to hide scratches and irregularities on the surface of the support, and to control the reflection of light on the surface of the support.The conductive layer may contain conductive particles and a resin. preferable.
Examples of the material for the conductive particles include metal oxides, metals, carbon black, and the like.
Examples of metal oxides include zinc oxide, aluminum oxide, indium oxide, silicon oxide, zirconium oxide, tin oxide, titanium oxide, magnesium oxide, antimony oxide, bismuth oxide, and the like. Examples of metals include aluminum, nickel, iron, nichrome, copper, zinc, and silver.

Among these, it is preferable to use metal oxides as the conductive particles, and it is particularly preferable to use titanium oxide, tin oxide, and zinc oxide.
When using a metal oxide as the conductive particles, the surface of the metal oxide may be treated with a silane coupling agent or the like, or the metal oxide may be doped with an element such as phosphorus or aluminum or an oxide thereof.
Further, the conductive particles may have a laminated structure including a core particle and a coating layer covering the particle. Examples of the core material particles include titanium oxide, barium sulfate, and zinc oxide. Examples of the coating layer include metal oxides such as tin oxide.

Further, when using a metal oxide as the conductive particles, the volume average particle diameter thereof is preferably 1 nm or more and 500 nm or less, more preferably 3 nm or more and 400 nm or less.
Examples of the resin include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, silicone resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, and alkyd resin.
Further, the conductive layer may further contain a masking agent such as silicone oil, resin particles, and titanium oxide.

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

<Undercoat layer>
In the present invention, an undercoat layer may be provided on the support or the conductive layer. By providing an undercoat layer, the adhesion function between layers can be enhanced and a charge injection blocking function can be imparted.
It is preferable that the undercoat layer contains resin. Alternatively, the undercoat layer may be formed as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group.

Examples of resins include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, polyvinylphenol resin, alkyd resin, polyvinyl alcohol resin, polyethylene oxide resin, polypropylene oxide resin, and polyamide resin. , polyamic acid resin, polyimide resin, polyamideimide resin, cellulose resin and the like.

Examples of the polymerizable functional group of the monomer having a polymerizable functional group include an isocyanate group, a blocked isocyanate group, a methylol group, an alkylated methylol group, an epoxy group, a metal alkoxide group, a hydroxyl group, an amino group, a carboxyl group, a thiol group, Examples include carboxylic acid anhydride groups and carbon-carbon double bond groups.
Further, the undercoat layer may further contain an electron transport substance, a metal oxide, a metal, a conductive polymer, etc. for the purpose of improving electrical properties. Among these, it is preferable to use electron transport substances and metal oxides.

Examples of electron transport substances include quinone compounds, imide compounds, benzimidazole compounds, cyclopentadienylidene compounds, fluorenone compounds, xanthone compounds, benzophenone compounds, cyanovinyl compounds, halogenated aryl compounds, silole compounds, boron-containing compounds, etc. . An undercoat layer may be formed as a cured film by using an electron transporting material having a polymerizable functional group as the electron transporting material and copolymerizing it with the above-mentioned monomer having a polymerizable functional group.

Examples of metal oxides include indium tin oxide, tin oxide, indium oxide, titanium oxide, zinc oxide, aluminum oxide, and silicon dioxide. Examples of metals include gold, silver, and aluminum.
Moreover, the undercoat layer may further contain an additive.
The average thickness of the undercoat layer is preferably 0.1 μm or more and 50 μm or less, more preferably 0.2 μm or more and 40 μm or less, and particularly preferably 0.3 μm or more and 30 μm or less.
The undercoat layer can be formed by preparing an undercoat layer coating solution containing each of the above-mentioned materials and a solvent, forming a coating film, and drying and/or curing the coating solution. Examples of the solvent used in the coating solution include alcohol solvents, ketone solvents, ether solvents, ester solvents, and aromatic hydrocarbon solvents.

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

(1) Laminated photosensitive layer The laminated photosensitive layer includes a charge generation layer and a charge transport layer.
(1-1) Charge Generating Layer The charge generating layer preferably contains a charge generating substance and a resin.
Examples of the charge generating substance include azo pigments, perylene pigments, polycyclic quinone pigments, indigo pigments, and phthalocyanine pigments. Among these, azo pigments and phthalocyanine pigments are preferred. Among the phthalocyanine pigments, oxytitanium phthalocyanine pigments, chlorogallium phthalocyanine pigments, and hydroxygallium phthalocyanine pigments are preferred.

The content of the charge generating substance in the charge generating layer is preferably 40% by mass or more and 85% by mass or less, more preferably 60% by mass or more and 80% by mass or less, based on the total mass of the charge generating layer. preferable.
Examples of resins include polyester resin, polycarbonate resin, polyvinyl acetal resin, polyvinyl butyral resin, acrylic resin, silicone resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, polyvinyl alcohol resin, cellulose resin, polystyrene resin, polyvinyl acetate resin. , polyvinyl chloride resin, etc. Among these, polyvinyl butyral resin is more preferred.

Further, the charge generation layer may further contain additives such as antioxidants and ultraviolet absorbers. Specific examples include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, and benzophenone compounds.
The average thickness of the charge generation layer is preferably 0.1 μm or more and 1 μm or less, more preferably 0.15 μm or more and 0.4 μm or less.
The charge generation layer can be formed by preparing a charge generation layer coating solution containing each of the above-mentioned materials and a solvent, forming this coating, and drying it. Examples of the solvent used in the coating solution include alcohol solvents, sulfoxide solvents, ketone solvents, ether solvents, ester solvents, and aromatic hydrocarbon solvents.

(1-2) Charge Transport Layer The charge transport layer preferably contains a charge transport substance and a resin.
Examples of the charge transport substance include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these substances. It will be done. Among these, triarylamine compounds and benzidine compounds are preferred.

The content of the charge transport substance in the charge transport layer is preferably 25% by mass or more and 70% by mass or less, more preferably 30% by mass or more and 55% by mass or less, based on the total mass of the charge transport layer. preferable.
Examples of the resin include polyester resin, polycarbonate resin, acrylic resin, and polystyrene resin. Among these, polycarbonate resins and polyester resins are preferred. As the polyester resin, polyarylate resin is particularly preferred.

The content ratio (mass ratio) of the charge transport material and the resin is preferably 4:10 to 20:10, more preferably 5:10 to 12:10.
Further, the charge transport layer may contain additives such as an antioxidant, an ultraviolet absorber, a plasticizer, a leveling agent, a slipperiness imparting agent, and an abrasion resistance improver. Specifically, hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oil, fluororesin particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, boron nitride particles. Examples include.

The average thickness of the charge transport layer is preferably 5 μm or more and 50 μm or less, more preferably 8 μm or more and 40 μm or less, and particularly preferably 10 μm or more and 30 μm or less.
The charge transport layer can be formed by preparing a charge transport layer coating solution containing each of the above-mentioned materials and a solvent, forming this coating film, and drying it. Examples of the solvent used in the coating liquid include alcohol solvents, ketone solvents, ether solvents, ester solvents, and aromatic hydrocarbon solvents. Among these solvents, ether solvents or aromatic hydrocarbon solvents are preferred.

(2) Single-layer type photosensitive layer A single-layer type photosensitive layer is formed by preparing a photosensitive layer coating solution containing a charge-generating substance, a charge-transporting substance, a resin, and a solvent, forming this coating film, and drying it. can do. The charge-generating substance, charge-transporting substance, and resin are the same as those exemplified in the above “(1) Laminated photosensitive layer”.
The average thickness of the single-layer type photosensitive layer is preferably 5 μm or more and 50 μm or less, more preferably 8 μm or more and 40 μm or less, and particularly preferably 10 μm or more and 30 μm or less.

<Protective layer>
In the present invention, a protective layer may be provided on the photosensitive layer. By providing a protective layer, durability can be improved.
Further, when the electrophotographic photoreceptor has a protective layer, the protective layer serves as a surface layer in the present invention. That is, the protective layer contains a copolymer of a composition containing a curable hole-transporting compound, a compound represented by formula (1), and a compound represented by formula (2).
The protective layer preferably contains conductive particles and/or a charge transport substance and a resin.

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

Examples of the resin include polyester resin, acrylic resin, phenoxy resin, polycarbonate resin, polystyrene resin, phenol resin, melamine resin, and epoxy resin. Among these, polycarbonate resin, polyester resin, and acrylic resin are preferred.
Further, the protective layer may be formed as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group. Examples of reactions at that time include thermal polymerization reactions, photopolymerization reactions, radiation polymerization reactions, and the like. Examples of the polymerizable functional group possessed by the monomer having a polymerizable functional group include an acrylic group and a methacryl group. As the monomer having a polymerizable functional group, a material having charge transport ability may be used.

The protective layer may contain additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, slipperiness agents, and abrasion resistance improvers. Specifically, hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oil, fluororesin particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, boron nitride particles. Examples include.
The average thickness of the protective layer is preferably 0.5 μm or more and 20 μm or less, and preferably 1 μm or more and 7 μm or less.
The protective layer can be formed by preparing a protective layer coating solution containing each of the above-mentioned materials and a solvent, forming a coating film, and drying and/or curing the coating solution. Examples of the solvent used in the coating solution include alcohol solvents, ketone solvents, ether solvents, sulfoxide solvents, ester solvents, and aromatic hydrocarbon solvents.

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

FIG. 1 shows an example of a schematic configuration of an electrophotographic apparatus having a process cartridge equipped with an electrophotographic photoreceptor.
Reference numeral 1 denotes a cylindrical electrophotographic photoreceptor, which is rotated around a shaft 2 in the direction of the arrow at a predetermined circumferential speed. The surface of the electrophotographic photoreceptor 1 is charged to a predetermined positive or negative potential by the charging means 3. Although the figure shows a roller charging method using a roller type charging member, charging methods such as a corona charging method, a proximity charging method, and an injection charging method may be employed.

The surface of the charged electrophotographic photoreceptor 1 is irradiated with exposure light 4 from an exposure means (not shown) to form an electrostatic latent image corresponding to target image information. The electrostatic latent image formed on the surface of the electrophotographic photoreceptor 1 is developed with toner contained in the developing means 5, and a toner image is formed on the surface of the electrophotographic photoreceptor 1. The toner image formed on the surface of the electrophotographic photoreceptor 1 is transferred onto a transfer material 7 by a transfer means 6. The transfer material 7 onto which the toner image has been transferred is conveyed to a fixing means 8, undergoes a toner image fixing process, and is printed out outside the electrophotographic apparatus.

The electrophotographic apparatus may include a cleaning means 9 for removing deposits such as toner remaining on the surface of the electrophotographic photoreceptor 1 after transfer. Furthermore, a so-called cleaner-less system may be used in which the deposits are removed by a developing means or the like without separately providing a cleaning means. The electrophotographic apparatus may include a static elimination mechanism that eliminates static electricity from the surface of the electrophotographic photoreceptor 1 using pre-exposure light 10 from a pre-exposure means (not shown). Furthermore, a guide means 12 such as a rail may be provided in order to attach and detach the process cartridge of the present invention to and from the main body of the electrophotographic apparatus.
The electrophotographic photoreceptor of the present invention can be used in laser beam printers, LED printers, copying machines, facsimile machines, and multifunctional machines thereof.

Hereinafter, the present invention will be explained in more detail using Examples and Comparative Examples. The present invention is not limited in any way by the following examples unless it exceeds the gist thereof. In the following description of Examples, "parts" are based on mass unless otherwise specified. Further, Examples 1 and 4 to 20 are described as reference examples.

(Example 1)
<Manufacture of electrophotographic photoreceptor>
<Support>
A cylindrical aluminum cylinder having an outer diameter of 29.9 mm, an inner diameter of 28.5 mm, a length of 357.5 mm, and a thickness of 0.7 mm was used as a support.

<Undercoat layer>
100 parts by mass of zinc oxide particles (specific surface area: 19 m ² /g, powder resistance: 4.7×10 6 Ω·cm) as a metal oxide were stirred and mixed with 500 parts by mass of toluene. To this was added 0.8 parts by mass of N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane (trade name: KBM602, manufactured by Shin-Etsu Chemical Co., Ltd.) as a silane coupling agent, and the mixture was stirred for 6 hours. . Thereafter, toluene was distilled off under reduced pressure, and the mixture was heated and dried at 140° C. for 6 hours to obtain surface-treated zinc oxide particles.

Next, 15 parts by mass of polyvinyl butyral (trade name: Eslec (registered trademark) B BM-1, manufactured by Sekisui Chemical Co., Ltd.) and blocked isocyanate (trade name: Sumidur 3175, manufactured by Sumitomo Bayer Urethane Co., Ltd.) 15 parts by mass was dissolved in the mixed solution. The mixed solution is a mixed solution of 73.5 parts by mass of methyl ethyl ketone and 73.5 parts by mass of 1-butanol.
To this solution were added 80.8 parts by mass of the surface-treated zinc oxide particles prepared above and 0.4 parts by mass of 2,3,4-trihydroxybenzophenone (manufactured by Tokyo Chemical Industry Co., Ltd.). This was dispersed for 3 hours in an atmosphere of 23° C. using a sand mill device using glass beads with a diameter of 0.8 mm. After dispersion, 0.01 part by mass of silicone oil (product name: SH28PA, manufactured by Dow Corning Toray Co., Ltd.), crosslinked polymethyl methacrylate (PMMA) particles (product name: TECHPOLYMER (registered trademark) SSX-103, Sekisui Plastics) 5.6 parts by mass (manufactured by Kogyo Co., Ltd., average primary particle size: 3.1 μm) was added and stirred to prepare a coating solution for an undercoat layer.
This undercoat layer coating solution was applied onto the support by dip coating, and the resulting coating film was dried at 160° C. for 40 minutes to form an undercoat layer having a thickness of 18 μm.

<Charge generation layer>
The following four materials were placed in a sand mill using glass beads with a diameter of 1 mm, and after being dispersed for 4 hours, 700 parts by mass of ethyl acetate was added to prepare a coating liquid for a charge generation layer.
・Crystalline hydroxygallium phthalocyanine crystal (charge generating substance) with strong peaks at 7.4° and 28.2° of Bragg angle 2θ±0.2° in CuKα characteristic X-ray diffraction: 20 parts by mass ・Polyvinyl butyral ( Product name: S-LEC (registered trademark) B BX-1 (manufactured by Sekisui Chemical Co., Ltd.): 10 parts by mass Compound represented by the following structural formula (A): 0.2 parts by mass Cyclohexanone: 600 parts by mass This charge The generation layer coating solution was applied onto the undercoat layer by dip coating, and the resulting coating was dried at 80° C. for 15 minutes to form a charge generation layer with a thickness of 0.18 μm.

<Charge transport layer>
A charge transport layer coating solution was prepared by dissolving the following four materials in a mixed solvent of 600 parts by mass of xylene and 200 parts by mass of dimethoxymethane.
・Compound represented by the following structural formula (B) (charge transport substance): 30 parts by mass ・Compound represented by the following structural formula (C) (charge transport substance): 60 parts by mass ・Represented by the following structural formula (D) Compound (charge transport material): 10 parts by mass - Compound represented by the following structural formula (E) (Mv: 20000): 0.02 part - Polycarbonate (product name: Iupilon (registered trademark) Z400, Mitsubishi Engineering Plastics Co., Ltd. ), bisphenol Z type polycarbonate): 100 parts by mass

This charge transport layer coating solution was applied onto the charge generation layer by dip coating, and the resulting coating film was dried at 110° C. for 30 minutes to form a charge transport layer having a thickness of 18 μm.

<Surface layer>
Next, a surface layer coating liquid was prepared using a material selected from the following material group.
Fluorine atom-containing acrylic resin (weight average molecular weight: 83,000, copolymerization ratio (F1)/(F2) = 1/1 (molar ratio)) was dissolved in a mixed solvent of 45 parts of 1-propanol and 45 parts of Zeorora H (manufactured by Nippon Zeon Co., Ltd.).

Then, 30 parts of fluorinated ethylene resin powder (trade name: Lublon L-2, manufactured by Daikin Industries, Ltd.) was added, and a high-pressure dispersion machine (trade name: Microfluidizer M-110EH, manufactured by Microfluidics, Inc., USA) was added. ) was dispersed. Thereby, a fluorinated ethylene resin dispersion was obtained.
Next, the following materials were stirred and uniformly dispersed to prepare a protective layer coating solution.
- 5.9 parts of Exemplified Compound 2-7 (hole transporting compound) as a compound represented by formula (2) - 0.7 parts of Exemplified Compound 1-2 as a compound represented by Formula (1) - Formula (9) Exemplary compound 5-3 0.7 parts, the above fluorinated ethylene resin dispersion 11.9 parts, 1-propanol 5.9 parts, Zeorola H 4.8 parts

This protective layer coating solution was applied onto the charge transport layer by dip coating, and the resulting coating film was dried at 50° C. for 10 minutes, and then subjected to polymerization curing treatment by electron beam irradiation and heating under the following conditions.
In an atmosphere with an oxygen concentration of 50 ppm or less, an aluminum cylinder was rotated at a speed of 300 rpm using an electron beam irradiation device under the conditions of an irradiation distance of 30 mm, an acceleration voltage of 70 kV, a beam current of 8 mA, and an irradiation time of 3.0 seconds. Irradiated with electron beam. After the electron beam irradiation, the surface of the protective layer coating was immediately heated to 135° C. over 24 seconds using an induction heating device while maintaining the oxygen concentration at 50 ppm or less.
Next, the aluminum cylinder was taken out into the air and further heated at 100° C. for 12 minutes to form a protective layer (surface layer) with a thickness of 5 μm.

<Surface shape>
Next, a mold member (mold) was installed in a press-contact shape transfer processing apparatus, and surface processing was performed on the produced electrophotographic photoreceptor before the formation of recesses.
FIG. 3 shows an example of a perspective view of a press-contact shape transfer processing apparatus for forming a recess on the outer circumferential surface of an electrophotographic photoreceptor. As shown in FIG. 3, the press-contact shape transfer processing apparatus includes a mold 52, a pressure member 53, and a support member 54. The mold shown in FIG. 4 was installed in the press-contact shape transfer processing apparatus shown in FIG. 3, and surface processing was performed on the outer circumferential surface of the produced electrophotographic photoreceptor 51 before concave portions were formed.

FIG. 4 is a diagram showing molds used in Examples and Comparative Examples. 4(a) is a plan view schematically showing the mold, and FIG. 4(b) is a schematic cross-sectional view in the axial direction of the electrophotographic photoreceptor 51 of the convex portion of the mold (in the SS' cross section of FIG. 4(a)). sectional view). FIG. 4(c) is a circumferential cross-sectional view of the electrophotographic photoreceptor 51 of the convex portion of the mold (a cross-sectional view taken along the line T-T' in FIG. 4(a)). The mold shown in FIG. 4 has a convex portion with a maximum width X: 50 μm, a maximum length Y: 75 μm, an area ratio of 56%, and a height H: 4 μm.

The maximum width X is the maximum width in the axial direction of the electrophotographic photoreceptor 51 when the convex portion on the mold is viewed from above.
The maximum length Y is the maximum length in the circumferential direction of the electrophotographic photoreceptor 51 when the convex portion on the mold is viewed from above.
The area ratio is the ratio of the area of the convex portion to the entire surface when the mold is viewed from above.

During processing, the temperatures of the electrophotographic photoreceptor 51 and the mold were controlled so that the surface temperature of the electrophotographic photoreceptor 51 was 120°C. Then, while pressing the mold against the electrophotographic photoreceptor with a pressure of 7.0 MPa using a pressure member, the electrophotographic photoreceptor 51 is rotated in the circumferential direction, and the pressure member 53 is moved in the direction indicated by the arrow 55. Then, recesses were formed on the entire surface layer (peripheral surface) of the electrophotographic photoreceptor 51. In this way, an electrophotographic photoreceptor 51 having recesses formed over the entire surface layer (peripheral surface) was manufactured.

The surface of the electrophotographic photoreceptor 51 obtained was observed under magnification with a 50x lens using a laser microscope (product name: Observations were made. During observation, adjustments were made so that there was no inclination in the longitudinal direction of the electrophotographic photoreceptor 51, and in the circumferential direction so that the apex of the arc of the electrophotographic photoreceptor 51 was in focus. The enlarged images were linked using an image linking application to obtain a square area of 500 μm on each side. The obtained results were then filtered using the attached image analysis software by selecting the image processing height data and using the filter type median.

As a result of the above observation, the depth of the recess was 2 μm, the maximum width of the opening of the recess in the axial direction was 50 μm, the maximum length of the opening of the recess in the circumferential direction was 75 μm, and the area was 140,000 μm ² . Note that the area refers to the area of the recess when the surface of the electrophotographic photoreceptor 51 is viewed from above, and means the area of the opening of the recess.
As described above, an electrophotographic photoreceptor according to Example 1 was produced.

(Examples 2 to 6)
In Examples 2 to 6, photoreceptors according to Examples 2 to 6 were produced in the following manner by changing the mass ratio of each material as shown in Table 1 below.

(Example 7)
<Support>
An aluminum cylinder having an outer diameter of 30 mm, an inner diameter of 28 mm, a length of 340 mm, and a wall thickness of 1 mm was used as a support (electroconductive support).
<Undercoat layer>
100 parts of zinc oxide particles (specific surface area: 15 m ² /g, average particle diameter 70 nm) were stirred and mixed with 500 parts of toluene, and 1.3 parts of a silane coupling agent (KBM503, manufactured by Shin-Etsu Chemical Co., Ltd.) was added to this. and stirred for 2 hours. Thereafter, toluene was distilled off under reduced pressure, and the mixture was heated and dried at 120° C. for 3 hours to obtain surface-treated zinc oxide particles.

Next, 110 parts of surface-treated zinc oxide particles were stirred and mixed with 500 parts of tetrahydrofuran, a solution of 0.6 parts of alizarin dissolved in 50 parts of tetrahydrofuran was added, and the mixture was stirred at 50° C. for 5 hours. Thereafter, the zinc oxide particles to which alizarin was added were filtered out by vacuum filtration, and further dried under reduced pressure at 60°C to obtain zinc oxide particles to which alizarin was added.
Next, 60 parts of zinc oxide particles to which alizarin was added, 15 parts of polyvinyl butyral resin (S-LEC BM-1, manufactured by Sekisui Chemical Co., Ltd.) as a polyol resin, and blocked isocyanate (Sumidur 3175, Sumika Co., Ltd.) were added. 38 parts of a solution prepared by mixing 13.5 parts of Bestlaurethane Co., Ltd. with 85 parts of methyl ethyl ketone and 25 parts of methyl ethyl ketone were mixed and dispersed for 2 hours using a sand mill device using glass beads with a diameter of 1 mm. To the resulting dispersion were added 0.005 parts of dioctyltin dilaurate as a catalyst and 40 parts of silicone resin particles (Tospearl 145, manufactured by GE Toshiba Silicone Co., Ltd.) to prepare a coating solution for an undercoat layer.
This undercoat layer coating solution was dip coated onto the aluminum cylinder to form a coating film, and the resulting coating film was dried at 170°C for 40 minutes to form an undercoat layer with a thickness of 20 μm. .

<Charge generation layer>
Hydroxygallium phthalocyanine having diffraction peaks at 7.3°, 16.0°, 24.9°, and 28.0° of the Bragg angle 2θ ± 0.2° of CuKα characteristic X-ray diffraction was prepared as a charge generating substance. did. A mixture consisting of 15 parts of this hydroxygallium phthalocyanine, 10 parts of vinyl chloride/vinyl acetate copolymer resin (VMCH, manufactured by Nippon Unicar Co., Ltd.), and 200 parts of n-butyl acetate was mixed in a sand mill using glass beads with a diameter of 1 mmφ. Dispersion was performed using an apparatus for 4 hours. 175 parts of n-butyl acetate and 180 parts of methyl ethyl ketone were added to the resulting dispersion to prepare a coating solution for a charge generation layer. This charge generation layer coating liquid is applied onto the undercoat layer by dip coating to form a coating film, and the resulting coating film is heated and dried at a temperature of 100°C for 5 minutes to generate a charge with a thickness of 0.2 μm. formed a layer.

<Charge transport layer>
45 parts of N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[1,1']biphenyl-4,4'-diamine as a charge transport material, and bisphenol Z polycarbonate resin ( A charge transport layer coating solution was prepared by adding and dissolving 55 parts of PCZ500 (viscosity average molecular weight: 50,000) in 800 parts of chlorobenzene. This charge transport layer coating liquid was applied onto the charge generation layer by dip coating to form a coating film, and the resulting coating film was dried at 130° C. for 45 minutes to form a charge transport layer with a thickness of 20 μm.

<Surface layer>
After mixing 60 parts of polytetrafluoroethylene particles (Luburon L-2, manufactured by Daikin Industries, Ltd.), 3 parts of a fluorine atom-containing resin (GF300, manufactured by Toagosei Co., Ltd.), and 140 parts of cyclopentanol, A dispersion liquid for a protective layer was prepared by dispersing with a dispersing machine.
Next, the following materials were dissolved in 80 parts of cyclopentanol and mixed with 100 parts of a protective layer dispersion liquid to prepare a protective layer coating liquid.
- 44 parts of Exemplified Compound 3-2 as a compound represented by formula (3) - 7 parts of Exemplified Compound 1-2 as a compound represented by Formula (1) - Exemplified Compound 5-2 21 parts as a compound represented by Formula (9) 1 part Polymerization initiator (OTazo-15, manufactured by Otsuka Chemical Co., Ltd.) This protective layer coating solution was dip coated onto the charge transport layer to form a coating film. After air drying at room temperature (25° C.) for 30 minutes, the coating film was cured by heating at 150° C. for 45 minutes in a nitrogen atmosphere with an oxygen concentration of 200 ppm to form a protective layer with a thickness of 15 μm.
In this way, an electrophotographic photoreceptor was produced.

(Examples 8 to 10)
In Examples 8 to 10, electrophotographic photoreceptors were produced in the same manner as in Example 7 except that the mass ratio of each material was changed as shown in Table 1 below.

(Example 11)
Exemplary Compound 2-7 was changed to Exemplary Compound 4-2, and the mass ratio of each material was set as shown in Table 1.
Except for the above, an electrophotographic photoreceptor was produced in the same manner as in Example 1.

(Examples 12 to 14)
In Examples 12 to 14, electrophotographic photoreceptors were produced in the same manner as in Example 11, except that the mass ratio of each material was changed as shown in Table 1 below.

(Example 15)
In Example 1, the manufacturing method for the surface layer and subsequent layers was changed as follows.
<Surface layer>
A coating solution for a protective layer was prepared by mixing the following materials.
- 44 parts of Exemplified Compound 4-1 (hole transporting compound) as a compound represented by formula (7) - 7 parts of Exemplified Compound 1-2 as a compound represented by Formula (1) - Compound represented by Formula (9) Exemplified Compound 5-2 21 parts Photopolymerization initiator 1-hydroxycyclohexylphenyl ketone 0.5 parts Tetrahydrofuran 80 parts Next, this protective layer coating solution was applied onto the charge transport layer by dip coating to form a coating film. The resulting coating film was dried at 60° C. for 5 minutes. After drying, ultraviolet rays were irradiated for 120 seconds at an irradiation intensity of 700 mW/cm ² using a metal halide lamp with an output of 160 W/cm 2 . Thereafter, heat treatment was performed at 130° C. for 30 minutes to form a protective layer having a thickness of 5.0 μm.
In this way, an electrophotographic photoreceptor was produced.

(Examples 16 to 18)
In Examples 16 to 18, electrophotographic photoreceptors were produced in the same manner as in Example 15, except that the mass ratio of each material was changed as shown in Table 1 below.

(Example 19)
The hole transporting compound contained in the surface layer coating liquid was changed from Exemplary Compound 4-1 to Exemplary Compound 10-1.
Except for the above, an electrophotographic photoreceptor was produced in the same manner as in Example 18.

(Example 20)
The content of the hole transporting compound (exemplified compound 10-1) contained in the surface layer coating liquid was changed from 66 parts to 55 parts.
The content of Exemplified Compound 1-2 was changed from 8 parts to 18 parts.
Except for the above, an electrophotographic photoreceptor was produced in the same manner as in Example 19.

(Comparative example 1)
The hole transporting compound contained in the surface layer coating solution was changed from Exemplified Compound 2-7 to Comparative Compound 11-1.
Further, the compound represented by formula (1) and the compound represented by formula (9) were not used.
Except for the above, an electrophotographic photoreceptor was produced in the same manner as in Example 1.

(Comparative example 2)
The compound represented by formula (1) contained in the surface layer coating liquid was changed from Exemplified Compound 1-2 to Exemplified Compound 1-8.
Further, the content ratio of Exemplary Compound 1-8 was set to the value shown in Table 1.
Furthermore, it was decided not to use a hole-transporting compound and a compound represented by formula (9).
Except for the above, an electrophotographic photoreceptor was produced in the same manner as in Example 1.

(Comparative example 3)
The compound represented by formula (1) contained in the surface layer coating liquid was changed from 0.7 parts of Exemplified Compound 1-2 to 6.6 parts of Exemplified Compound 1-8.
Furthermore, the compound represented by formula (9) was changed from 0.9 parts of Exemplified Compound 5-2 to 0.8 parts of Exemplified Compound 5-1.
Except for the above, an electrophotographic photoreceptor was produced in the same manner as in Example 1.

[evaluation]
(Condensation recovery)
The electrophotographic photoreceptors manufactured in each of the Examples and Comparative Examples were evaluated using a process cartridge for cyan color of a modified electrophotographic apparatus (copying machine) (product name: iR-ADV C5255, manufactured by Canon Inc.). It was attached to the station. Modifications include adjusting and measuring the image exposure amount, the amount of current flowing from the charging roller (roller-shaped charging member) to the support of the electrophotographic photoreceptor (hereinafter also referred to as total current), and the voltage applied to the charging roller. Modified so that it can be done. Condensation recovery was evaluated under the conditions shown below.
Leave to stand overnight in a low-temperature environment with a temperature of 2.5° C. and a relative humidity of 50%. Thereafter, the main body was moved to a normal temperature environment at a temperature of 23° C. and a relative humidity of 50%, and left to stand for 120 minutes. After 120 minutes, the power of the main body was turned on, and at 135 minutes and 165 minutes, images were printed on A4 landscape paper using a test chart containing a grid image with an image ratio of 3.6%. If the grid image in the test chart was interrupted, it was determined that there was an abnormality, and if it was not interrupted, it was determined that there was no abnormality, and a ranking was performed.
The evaluation ranks were as follows.
Rank 3: No abnormality is observed in the image of the test chart printed 135 minutes after moving to the normal temperature environment.
Rank 2: No abnormality was observed in the image of the test chart printed 165 minutes after moving to the normal temperature environment.
Rank 1: An abnormality is seen on the test chart printed 165 minutes after moving to a normal temperature environment.

(Potential fluctuation during repeated evaluation)
The electrophotographic photoreceptors manufactured in each of the Examples and Comparative Examples were evaluated using a process cartridge for cyan color of a modified electrophotographic apparatus (copying machine) (product name: iR-ADV C5255, manufactured by Canon Inc.). It was attached to the station. Modifications were made so that the amount of image exposure, the amount of current flowing from the charging roller to the support of the electrophotographic photoreceptor (hereinafter also referred to as total current), and the voltage applied to the charging roller could be adjusted and measured. Environmental changes were evaluated under the conditions shown below.

First, the "initial potential" of the image exposure section VL was measured in a high temperature, high humidity environment at a temperature of 30.degree. C. and a relative humidity of 80%.
Next, in the same high-temperature, high-humidity environment, after 1000 consecutive images were formed on A4 landscape paper using a test chart with an image ratio of 1%, the "potential after 1000 sheets" of the image exposure section VL was determined. was measured.
Then, the value of "potential after 1000 sheets - initial potential" of the image exposure portion VL was calculated and set as ΔVL(HH).
Similarly, in a low-temperature, low-humidity environment with a temperature of 15°C and a relative humidity of 5%, the "initial potential" and "potential after 1000 sheets" of the image exposure section VL are measured, and "potential after 1000 sheets - initial potential" is calculated. was calculated and set as ΔVL(LL).
Next, "ΔVL (HH) - ΔVL (LL)" was calculated and used as the result of environmental change.
In the present invention, if the environmental fluctuation (ΔVL(HH) - ΔVL(LL)) is less than 10V, and ΔVL(HH) and ΔVL(LL) are each less than 30V, there is no problem with the characteristics of the electrophotographic photoreceptor. I decided that.

As a result of the evaluation, the examples showed good dew condensation recovery, and environmental fluctuations during repeated use were sufficiently suppressed, with no problems. In the comparative example, dew condensation recovery deteriorated and there were problems with environmental fluctuations during repeated use.

1 Electrophotographic photoreceptor 2 Axis 3 Charging means 4 Exposure light 5 Developing means 6 Transfer means 7 Transfer material 8 Fixing means 9 Cleaning means 10 Pre-exposure light 11 Process cartridge 12 Guide means 21 Support 22 Undercoat layer 23 Charge generation layer 24 Charge transport layer 25 Protective layer (surface layer)

Claims (4)

An electrophotographic photoreceptor comprising a support, a photosensitive layer as a surface layer , or a support , a photosensitive layer , and a protective layer as a surface layer in this order,
The surface layer contains a hole-transporting compound represented by the following formula (2-7) , a compound represented by the following formula ( 1-2 ) , and a compound represented by the following formula (5-3). An electrophotographic photoreceptor comprising a polymer of the composition.

The mass content of the compound represented by the formula ( 5-3 ) in the composition is 0.1 times or more the mass content of the hole transporting compound represented by the formula (2-7). The electrophotographic photoreceptor according to claim 1 , which is 1.0 times or less. A main body of an electrophotographic apparatus, which integrally supports the electrophotographic photoreceptor according to claim 1 or 2 and at least one means selected from the group consisting of charging means, developing means, transfer means , and cleaning means. A process cartridge that can be attached and detached at will. An electrophotographic apparatus comprising the electrophotographic photoreceptor according to claim 1 or 2 , charging means, exposure means, developing means , and transfer means .

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