JP2023034475A - Electro-photographic photoreceptor, process cartridge, and electro-photographic device - Google Patents

Abstract

To provide an electro-photographic photoreceptor which can have excellent wear resistance, in which the surface potential hardly changes even when exposed to light.SOLUTION: Provided is an electro-photographic photoreceptor having a support medium and a photosensitive layer on the support medium, wherein a surface layer of the electro-photographic photoreceptor is a polymer film of a composition containing (A) a hole transportable compound having a chain polymerizable group and (B) inorganic particles having been surface-treated with a compound indicated by formula (1).SELECTED DRAWING: None

Description

The present disclosure relates to an electrophotographic photoreceptor, a process cartridge and an electrophotographic apparatus.

Electrophotographic photoreceptors mounted in electrophotographic apparatuses include organic electrophotographic photoreceptors (hereinafter referred to as "electrophotographic photoreceptors") containing organic photoconductive substances (charge-generating substances). has been done. In recent years, for the purpose of prolonging the life of electrophotographic photoreceptors and improving image quality, electrophotographic photoreceptors are required to be excellent in wear resistance and less likely to cause image defects.

For example, in Patent Document 1, a composition having a chain polymerizable compound having a charge-transporting property and metal oxide particles surface-treated with the chain polymerizable compound is cured to form a surface layer, thereby improving abrasion resistance and image quality. An organophotoreceptor is disclosed that can improve flow and image blur.

JP 2010-169725 A

One aspect of the present disclosure is directed to providing an electrophotographic photoreceptor that can have excellent abrasion resistance and whose surface potential is less likely to change even when exposed to light.

Another aspect of the present disclosure is directed to providing a process cartridge having the electrophotographic photoreceptor according to the present disclosure.

Another aspect of the present disclosure is directed to providing an electrophotographic apparatus having the electrophotographic photoreceptor according to the present disclosure.

According to one aspect of the present disclosure, an electrophotographic photoreceptor having a support and a photosensitive layer on the support,
The surface layer of the electrophotographic photoreceptor is
(A) a hole-transporting compound having a chain polymerizable group; and (B) inorganic particles surface-treated with a compound represented by the following formula (1);
There is provided an electrophotographic photoreceptor characterized by being a polymer film of a composition containing

(In formula (1), Ln is a straight-chain alkylene group having 6 or more and 10 or less carbon atoms. R ¹ to R ³ are each independently an alkoxy group or an alkyl group, and R ¹ to R ³ is an alkoxy group.Fn is a chain polymerizable group that copolymerizes with the chain polymerizable group of the hole-transporting compound.)
Further, according to one aspect of the present disclosure, a process cartridge having the electrophotographic photoreceptor according to the present disclosure,
The process cartridge integrally supports at least one means selected from the group consisting of charging means, exposure means, development means, and transfer means, and is detachable from the main body of the electrophotographic apparatus. is provided.

Further, according to one aspect of the present disclosure, an electrophotographic apparatus having the electrophotographic photoreceptor according to the present disclosure,
An electrophotographic apparatus is provided, characterized in that the electrophotographic apparatus has charging means, exposure means, developing means and transfer means.

According to one aspect of the present disclosure, it is possible to provide an electrophotographic photoreceptor that can have excellent wear resistance and whose surface potential is less likely to change even when exposed to light.

Further, according to another aspect of the present disclosure, it is possible to provide a process cartridge having the electrophotographic photoreceptor according to the present disclosure.

Further, according to another aspect of the present disclosure, it is possible to provide an electrophotographic apparatus having the electrophotographic photoreceptor according to the present disclosure.

1 is a diagram showing an example of a schematic configuration of an electrophotographic apparatus including a process cartridge having an electrophotographic photoreceptor of the present disclosure; FIG. 1 is a diagram showing an example of the layer structure of an electrophotographic photoreceptor of the present disclosure; FIG. FIG. 3 is a diagram showing a pressure contact shape transfer processing apparatus used in an example and a comparative example of the present disclosure; FIG. 3 is a diagram showing a mold used in Examples and Comparative Examples of the present disclosure;

In the present disclosure, unless otherwise specified, the descriptions of “○○ or more and XX or less” and “○○ to XX” that represent numerical ranges mean numerical ranges including the lower and upper limits that are endpoints.

<Circumstances leading to the invention>
According to the technique according to Patent Document 1, it is certainly possible to have excellent wear resistance. On the other hand, the inventors of the present invention have found that when an electrophotographic photoreceptor is exposed to light, the surface potential of the electrophotographic photoreceptor fluctuates, which is a so-called photo-fatigue phenomenon.

This is thought to be due to the bonding between the surface-treated inorganic particles and the hole-transporting compound when the surface layer is cured. It is believed that the generated charges are easily trapped in the inorganic particles.
It is believed that charges generated by light exposure are trapped in the inorganic particles and stay in the surface layer, making it easier to prevent the movement of charges newly generated when exposed to light in a copier. As a result, it is thought that the surface potential of the electrophotographic photoreceptor is likely to be insufficiently attenuated in some areas even in areas exposed in the copying machine, and the surface potential of the electrophotographic photoreceptor tends to fluctuate.

The electrophotographic photoreceptor may be exposed to light when it is mounted on a machine or during maintenance work of the machine. It was found that it was necessary to improve this point.

Based on the above considerations, the present inventors have investigated an electrophotographic photoreceptor that can have abrasion resistance and that is less prone to fluctuations in surface potential even when exposed to light. As a result, the surface layer of the electrophotographic photoreceptor is a polymer film of a composition containing inorganic particles surface-treated with the compound represented by formula (1). is obtained.

By setting the number of carbon atoms in the alkylene group represented by Ln in formula (1) within a specific range, the distance between the structure having a hole-transporting property and the inorganic particles does not become too close, and the charge generated by light is reduced. It is thought that it becomes difficult to be trapped by inorganic particles. As a result, the present inventors speculate that the surface potential of the electrophotographic photosensitive member is less likely to be canceled during exposure, and the surface potential of the electrophotographic photosensitive member is less likely to fluctuate.

[(A) Hole-transporting compound having a chain polymerizable group]
The surface layer of the electrophotographic photoreceptor is a polymer film of a composition containing a hole-transporting compound having a chain polymerizable group and inorganic particles surface-treated with the compound represented by the above formula (1).

Examples of the chain polymerizable group possessed by the hole-transporting compound include an acryloyloxy group, a methacryloyloxy group, an alkoxysilyl group, and an epoxy group. Among these, an acryloyloxy group and a methacryloyloxy group are preferred. Moreover, from the viewpoint of abrasion resistance, the hole-transporting compound preferably has two or more chain polymerizable groups. Also, the hole-transporting compound preferably has a triphenylamine skeleton.

Specific examples of the hole-transporting compound having a chain polymerizable group are shown below. However, it is not limited to the following examples.

Among these, at least one selected from the group consisting of Exemplified Compound Moiety 2-7, Exemplified Compound 2-28, Exemplified Compound 2-37, and Exemplified Compound 2-38 is preferable. More preferably, it is at least one of Exemplified Compound 2-7 and Exemplified Compound 2-28.

Further, the hole-transporting compound according to the present disclosure is preferably a compound represented by the following formula (CT-1).

(In the above formula (CT-1), Ar ¹¹ to Ar ¹³ are each independently a substituted or unsubstituted aryl group. At least one of Ar ¹¹ to Ar ¹³ is represented by the following formula (P-1 ), a functional group represented by formula (P-2) below, and a functional group represented by formula (P-3) below.

(In formula (P-1) above, Z ¹¹ is a single bond or an alkylene group having 1 to 6 carbon atoms, and X ¹¹ is a hydrogen atom or a methyl group.
In formula (P-2) above, Z ²¹ is a single bond or an alkylene group having 1 to 6 carbon atoms.
In formula (P-3) above, Z ³¹ is a single bond or an alkylene group having 1 to 6 carbon atoms. ))
Ar ¹¹ to Ar ¹³ may have an alkyl group having 1 to 6 carbon atoms. Further, each aryl group in the above formula (CT-1) is preferably independently a phenyl group, a biphenylyl group or a fluorenyl group. Further, the alkylene groups in the above formulas (P-1) to (P-3) are each independently an ethylene group, a 1,3-propylene group, a 1,2-propylene group, or a 1,4-butylene group. is preferably

[(B) Inorganic particles surface-treated with a compound represented by formula (1)]
The inorganic particles according to the present disclosure are inorganic particles surface-treated with the compound represented by formula (1).

(In formula (1), Ln is a straight-chain alkylene group having 6 or more and 10 or less carbon atoms. R ¹ to R ³ are each independently an alkoxy group or an alkyl group, and R ¹ to R ³ is an alkoxy group.Fn is a chain polymerizable group that copolymerizes with the chain polymerizable group of the hole-transporting compound.)
Since the surface layer is a polymer film of a composition containing the inorganic particles according to the present disclosure and a hole-transporting compound having a chain polymerizable group, an electrophotographic photoreceptor having excellent abrasion resistance can be obtained. Cheap.

Ln in formula (1) is a linear alkylene group having 6 or more and 10 or less carbon atoms. When the number of carbon atoms in Ln is 6 or more, the distance between the hole-transporting structure and the alkoxysilyl group bonded to the inorganic particles is not too close, and even when exposed to light, the electrophotographic photoreceptor It is considered that the surface potential of the surface becomes difficult to change. Further, when the number of carbon atoms is 10 or less, the density of the polymer film is unlikely to be excessively low and sufficient hardness is likely to be obtained, so an electrophotographic photoreceptor having excellent abrasion resistance can be easily obtained.

Moreover, Fn in formula (1) is preferably any selected from the group consisting of an acryloyloxy group, a methacryloyloxy group, an alkoxysilyl group, and an epoxy group. More preferably, it is an acryloyloxy group or a methacryloyloxy group. Also, R ¹ to R ³ in formula (1) preferably have 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms.

From the viewpoint that the abrasion resistance and surface potential of the electrophotographic photoreceptor are less likely to fluctuate, the content ratio of the inorganic particles according to the present disclosure is 30.0 to 85.0 mass with respect to the mass of the hole-transporting compound. %. More preferably 50.0% by mass or more, more preferably 55.0% by mass or more. Moreover, it is more preferable that it is 80.0 mass % or less.

The inorganic particles according to the present disclosure can be obtained by subjecting the inorganic particles to surface treatment using the compound represented by Formula 1 as a surface treatment agent. A single surface treatment agent or a plurality of surface treatment agents may be used for the surface treatment.

Examples of inorganic particles to be surface-treated include the following.
Magnesium oxide, zinc oxide, lead oxide, aluminum oxide, silicon oxide, tantalum oxide, indium oxide, bismuth oxide, yttrium oxide, cobalt oxide, copper oxide, manganese oxide, selenium oxide, iron oxide, zirconium oxide, germanium oxide, tin oxide , titanium oxide, niobium oxide, molybdenum oxide, vanadium oxide, silica (silicon dioxide) and other inorganic oxide particles.

Among these, at least one particle selected from the group consisting of zinc oxide, tin oxide, titanium oxide, aluminum oxide, and silica is more preferable, and an electrophotographic photoreceptor having excellent abrasion resistance can be obtained. Cheap. Silica particles are more preferred.

The inorganic particles surface-treated with the compound represented by the formula (1) have a structure represented by the following formula (2) or (3) on the surface.

(In the formulas (2) to (4), the oxygen atom is bound to the inorganic particles. Ln is a linear alkylene group having 6 to 10 carbon atoms. Further, Fn is the above A chain-polymerizable group that copolymerizes with the chain-polymerizable group possessed by the hole-transporting compound.In the formula (3), ^R4 is an alkyl group.In the formula (4), R5 and R6 are each independently indicates an alkyl group.)
Examples of the compound represented by the above formula (1) include the following compounds.

Among the above exemplary compounds, the compound represented by formula (1) is preferably at least one selected from the group consisting of exemplary compounds 3-1 to 3-3 and 3-5. More preferably, it is at least one selected from the group consisting of Exemplified Compounds 3-1 to 3-3.

As a method of surface-treating the inorganic particles, a wet method of mixing and stirring the inorganic particles and the surface-treating agent in a solvent and removing the solvent can be used. It is preferable to use 0.1 to 200 parts, more preferably 7 to 70 parts, and 50 to 5000 parts of a solvent for 100 parts of the substrate fine particles. The configuration of the inorganic particles according to the present disclosure can be controlled by changing the inorganic particles and the surface treatment agent used for surface treatment.

<Chain polymerizable compound having no hole-transporting property>
The surface layer of the electrophotographic photoreceptor may contain a chain polymerizable compound having no hole transport property. The chain polymerizable compound having no hole-transporting property is a monomer having no hole-transporting property, and is polymerized (cured) by irradiation with actinic rays such as ultraviolet rays and electron beams to form an electrophotographic photoreceptor. It means a monomer capable of forming a binder resin. Preferred examples of the chain polymerizable compound having no hole-transporting properties include styrene-based monomers, acrylic-based monomers, methacrylic-based monomers, vinyltoluene-based monomers, vinyl acetate-based monomers, and N-vinylpyrrolidone-based monomers.

The chain polymerizable compound having no hole-transport property is preferably a chain polymerizable compound having an acryloyloxy group or a methacryloyloxy group from the viewpoint of enabling curing with a small amount of light or a short time.

Specific examples of chain polymerizable compounds that do not have hole-transport properties include the following.

Among the above, at least one selected from the group consisting of Exemplary Compounds 4-1, 4-2, 4-3, and 4-11 is particularly preferred from the viewpoint of abrasion resistance. More preferably, at least one of Exemplified Compounds 4-1 and 4-11.

Moreover, various additives may be added to the surface layer. Examples of additives that can be used include anti-degradation agents such as antioxidants and ultraviolet absorbers, and lubricants such as polytetrafluoroethylene (PTFE) particles and carbon fluoride. In addition, a polymerization controller such as a polymerization reaction initiator and a polymerization reaction terminator, a leveling agent such as a siloxane-modified acrylic compound and silicone oil, and a surfactant can also be used. A siloxane-modified acrylic compound is a compound in which siloxane is introduced as a side chain into an acrylic polymer, and is obtained, for example, by copolymerizing an acrylic monomer and a siloxane having an acrylic group.

<Surface layer>
The surface layer according to the present disclosure is the outermost layer of the electrophotographic photoreceptor. That is, when the outermost layer of the electrophotographic photoreceptor is the charge transport layer, the charge transport layer is the surface layer according to the present disclosure.

As the solvent used for preparing the surface layer coating liquid, it is preferable to use a solvent that does not dissolve the layer provided below the surface layer. Preferred solvents include alcoholic solvents such as methanol, ethanol, propanol, isopropanol, 1-butanol, 2-butanol, 1-methoxy-2-propanol.

Further, the surface layer according to the present disclosure is formed by forming a coating film of a surface layer coating liquid containing a hole-transporting compound having a chain polymerizable group and the inorganic particles according to the present disclosure, and curing the coating film. It can be formed by (polymerizing).

Examples of means for curing the coating film of the surface layer coating liquid include a method of curing by irradiation with heat, ultraviolet rays, or electron beams. In order to maintain the strength of the surface layer and the durability of the electrophotographic photoreceptor, curing is preferably performed using ultraviolet rays or electron beams, more preferably using electron beams.

Polymerization using an electron beam is preferable because a very dense (high density) cured product (three-dimensional crosslinked structure) can be obtained and a surface layer having higher durability can be obtained. In the case of electron beam irradiation, accelerators include, for example, a scanning type, an electrocurtain type, a broad beam type, a pulse type, and a laminar type. When an electron beam is used, the acceleration voltage of the electron beam is preferably 120 kV or less from the viewpoint of suppressing deterioration of material properties due to the electron beam without impairing the polymerization efficiency. The electron beam absorption dose on the surface of the coating film of the surface layer coating liquid is preferably 1 kGy or more and 50 kGy or less, more preferably 5 kGy or more and 10 kGy or less.

Further, when the composition is cured (polymerized) using an electron beam, the composition may be irradiated with an electron beam in an inert gas atmosphere and then heated in an inert gas atmosphere for the purpose of suppressing the polymerization inhibition effect of oxygen. preferable. Examples of inert gases include nitrogen, argon, and helium.

In the case of irradiation with ultraviolet rays or electron beams, it is preferable to heat the electrophotographic photosensitive member to 100° C. or more and 170° C. or less after irradiation. By doing so, it is possible to obtain a surface layer that has higher durability and suppresses image defects.

<Electrophotographic photoreceptor>
An electrophotographic photoreceptor according to the present disclosure is an electrophotographic photoreceptor having a support and a photosensitive layer on the support.

The photosensitive layer includes a single-layer photosensitive layer containing both a charge-generating substance and a charge-transporting substance, and a laminate-type photosensitive layer separated into a charge-generating layer containing a charge-generating substance and a charge-transporting layer containing a charge-transporting substance. mentioned. In the present invention, it is preferably a laminated photosensitive layer.

FIG. 2 is a diagram showing an example of the layer structure of an electrophotographic photoreceptor. In FIG. 2, the electrophotographic photoreceptor has a support 21 , an undercoat layer 22 , a charge generation layer 23 , a first charge transport layer 24 and a second charge transport layer 25 . In this case, the second charge transport layer 25 is the surface layer. Also, when the second charge transport layer is not provided, the charge transport layer 24 is the surface layer.

As the configuration of the electrophotographic photoreceptor according to the present disclosure, the photosensitive layer preferably has a charge generation layer, a first charge transport layer, and a second charge transport layer in this order, and the second charge transport layer is the surface layer.

As a method for producing the electrophotographic photoreceptor of the present disclosure, there is a method of preparing a coating solution for each layer, which will be described later, coating the desired layers in order, and drying. At this time, the method of applying the coating liquid includes dip coating, spray coating, inkjet coating, roll coating, die coating, blade coating, curtain coating, wire bar coating, ring coating, and the like. Among these, dip coating is preferable from the viewpoint of efficiency and productivity.

Each configuration will be described below.

<Support>
The electrophotographic photoreceptor preferably has a support. The support is preferably a conductive support having electrical conductivity. Further, the shape of the support includes a cylindrical shape, a belt shape, a sheet shape, and the like. Among them, a cylindrical support is preferable. Further, the surface of the support may be subjected to electrochemical treatment such as anodization, blasting treatment, cutting treatment, or the like.

The material of the support is preferably metal, resin, glass, or the like. Examples of metals include aluminum, iron, nickel, copper, gold, stainless steel, and alloys thereof. Among them, an aluminum support using aluminum is preferable. Conductivity may be imparted to the resin or glass by treatment such as mixing or coating with a conductive material.

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

Materials for the conductive particles include metal oxides, metals, and carbon black. Metal oxides include zinc oxide, aluminum oxide, indium oxide, silicon oxide, zirconium oxide, tin oxide, titanium oxide, magnesium oxide, antimony oxide, and bismuth oxide. Metals include aluminum, nickel, iron, nichrome, copper, zinc, silver and the like.

Among these, metal oxides are preferably used as the conductive particles, and titanium oxide, tin oxide, and zinc oxide are particularly preferably used. When a metal oxide is used 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.

Also, the conductive particles may have a laminated structure including core particles and a coating layer that covers the particles. Examples of core material particles include titanium oxide, barium sulfate, and zinc oxide. Metal oxides, such as tin oxide, are mentioned as a coating layer.

When metal oxides are used as the conductive particles, the volume average particle diameter is preferably 1 nm or more and 500 nm or less, more preferably 3 nm or more and 400 nm or less.

Resins contained in the conductive layer include polyester resins, polycarbonate resins, polyvinylacetal resins, acrylic resins, silicone resins, epoxy resins, melamine resins, polyurethane resins, phenol resins, alkyd resins, and the like.

In addition, the conductive layer may further contain silicone oil, resin particles, masking agents such as titanium oxide, and the like.

The average film thickness of the conductive layer is preferably 1 μm or more and 50 μm or less, and particularly preferably 3 μm or more and 40 μm or less.

The conductive layer can be formed by preparing a conductive layer coating liquid containing each of the above materials and a solvent, forming a coating film thereon, and drying the coating film. Solvents used in the coating liquid include alcohol solvents, sulfoxide solvents, ketone solvents, ether solvents, ester solvents, aromatic hydrocarbon solvents and the like. Examples of the dispersion method for dispersing the conductive particles in the conductive layer coating liquid include methods using a paint shaker, a sand mill, a ball mill, and a liquid collision type high-speed disperser.

<Undercoat layer>
In the present disclosure, a subbing layer may be provided over the support or conductive layer. By providing the undercoat layer, the adhesion function between the layers is enhanced, and the charge injection blocking function can be imparted. The undercoat layer preferably contains a 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 resins, polycarbonate resins, polyvinyl acetal resins, acrylic resins, epoxy resins, melamine resins, polyurethane resins, phenol resins, polyvinyl phenol resins, alkyd resins, polyvinyl alcohol resins, polyethylene oxide resins, polypropylene oxide resins, and polyamide resins. , polyamic acid resins, polyimide resins, polyamideimide resins, cellulose resins, and the like.

The polymerizable functional group possessed by the monomer having a polymerizable functional group includes 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, Carboxylic anhydride groups, carbon-carbon double bond groups, and the like.

In addition, the undercoat layer may further contain a charge transport material, metal oxide, metal, conductive polymer, etc. for the purpose of enhancing electrical properties. Among these, charge transport substances and metal oxides are preferably used.

Examples of charge-transporting substances include quinone compounds, imide compounds, benzimidazole compounds, cyclopentadienylidene compounds, fluorenone compounds, xanthone compounds, benzophenone compounds, cyanovinyl compounds, halogenated aryl compounds, silole compounds, and boron-containing compounds. . A charge-transporting substance having a polymerizable functional group may be used as the charge-transporting substance, and the undercoat layer may be formed as a cured film by copolymerizing the charge-transporting substance with the above-mentioned monomer having a polymerizable functional group.

Metal oxides include indium tin oxide, tin oxide, indium oxide, titanium oxide, zinc oxide, aluminum oxide, and silicon dioxide. Metals include gold, silver, and aluminum.

In addition, the undercoat layer may further contain additives. The average film thickness of the undercoat layer is preferably 0.1 μm or more and 50 μm or less, more preferably 0.2 μm or more and 40 μm or less, and particularly preferably 0.3 μm or more and 30 μm or less.

The undercoat layer can be formed by preparing an undercoat layer coating solution containing each of the above materials and a solvent, forming a coating film, and drying and/or curing the coating film. Solvents used in the coating liquid include alcohol solvents, ketone solvents, ether solvents, ester solvents, aromatic hydrocarbon solvents and the like.

<Photosensitive layer>
The photosensitive layer of the electrophotographic photoreceptor is mainly classified into (1) laminated photosensitive layer and (2) 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 has a charge generation layer and a charge transport layer.

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

Examples of charge-generating substances 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, relative to the total mass of the charge-generating layer. preferable.

Examples of resins contained in the charge generation layer include the following.
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 preferable.

The charge generation layer may further contain additives such as antioxidants and UV absorbers. Specific examples include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, and the like. The average film thickness of the charge generation layer is preferably 0.1 μm or more and 1 μm or less, more preferably 0.15 μm or more and 0.4 μm or less.

The charge-generating layer can be formed by preparing a charge-generating layer coating solution containing the above materials and a solvent, forming a coating film, and drying the coating film. Solvents used in the coating liquid include alcohol solvents, sulfoxide solvents, ketone solvents, ether solvents, ester solvents, aromatic hydrocarbon solvents and the like.

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

Examples of charge-transporting substances include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these substances. 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, relative to the total mass of the charge transport layer. preferable.

Examples of resins include polyester resins, polycarbonate resins, acrylic resins, and polystyrene resins. Among these, polycarbonate resins and polyester resins are preferred. A polyarylate resin is particularly preferable as the polyester resin.

The content ratio (mass ratio) of the charge transport substance and the resin is preferably 4:10 to 20:10, more preferably 5:10 to 12:10.

The charge transport layer may also contain additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, slipperiness agents and wear resistance improvers. Specifically, the following are mentioned.
Hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluororesin particles, polystyrene resin particles, polyethylene resin particles, silicon dioxide particles, alumina particles, boron nitride particles, and the like.

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

The charge-transporting layer can be formed by preparing a charge-transporting-layer coating solution containing each of the materials and solvents described above, forming a coating film thereon, and drying the coating film. Solvents used in the coating liquid include alcohol solvents, ketone solvents, ether solvents, ester solvents, and aromatic hydrocarbon solvents. Among these solvents, ether solvents and aromatic hydrocarbon solvents are preferred.

Further, when the electrophotographic photoreceptor has a charge transport layer on its surface, the charge transport layer is the surface layer according to the present disclosure.

(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 film thickness of the single-layer type photosensitive layer is preferably from 5 μm to 50 μm, more preferably from 8 μm to 40 μm, and particularly preferably from 10 μm to 30 μm.

[Process cartridge, electrophotographic device]
The process cartridge of the present disclosure is a process cartridge having the electrophotographic photoreceptor of the present disclosure, wherein the process cartridge comprises at least one selected from the group consisting of charging means, exposure means, developing means, and transfer means. The means is integrally supported and is detachable from the main body of the electrophotographic apparatus.

Further, an electrophotographic apparatus of the present disclosure is an electrophotographic apparatus having the electrophotographic photoreceptor of the present disclosure, characterized in that the electrophotographic apparatus includes charging means, exposure means, developing means and transfer means. .

FIG. 1 shows an example of the schematic configuration of an electrophotographic apparatus having a process cartridge provided with an electrophotographic photosensitive member.

A cylindrical electrophotographic photosensitive member 1 is rotationally driven about a shaft 2 in the direction of the arrow at a predetermined peripheral speed. The surface of the electrophotographic photosensitive member 1 is charged to a predetermined positive or negative potential by charging means 3 . Although the drawing shows a roller charging method using a roller-type charging member, other charging methods such as a corona charging method, a proximity charging method, and an injection charging method may be used. The surface of the charged electrophotographic photosensitive member 1 is irradiated with exposure light 4 from an exposure means (not shown) to form an electrostatic latent image corresponding to desired image information. The electrostatic latent image formed on the surface of the electrophotographic photoreceptor 1 is developed with toner accommodated in the developing means 5 to form a toner image on the surface of the electrophotographic photoreceptor 1 . A toner image formed on the surface of the electrophotographic photosensitive member 1 is transferred onto a transfer material 7 by transfer means 6 . The transfer material 7 onto which the toner image has been transferred is conveyed to a fixing means 8 where the toner image is fixed and printed out of the electrophotographic apparatus. The electrophotographic apparatus may have a cleaning means 9 for removing deposits such as toner remaining on the surface of the electrophotographic photosensitive member 1 after transfer. Also, a so-called cleanerless system may be used in which the deposits are removed by developing means or the like without separately providing a cleaning means. The electrophotographic apparatus may have a charge removing mechanism for removing charges from the surface of the electrophotographic photosensitive member 1 with pre-exposure light 10 from a pre-exposure unit (not shown). Further, a guide means 12 such as a rail may be provided for attaching and detaching the process cartridge of the present disclosure to and from the main body of the electrophotographic apparatus.

The electrophotographic photoreceptor of the present disclosure can be used for laser beam printers, LED printers, copiers, facsimiles, and multifunction devices thereof.

The present disclosure will be described in more detail below using examples and comparative examples, but the present disclosure is not limited by these. In the description of the following examples, "parts" are based on mass unless otherwise specified.

First, production examples of inorganic particles A1 to A15 used in Examples and Comparative Examples are described.

<Production example of inorganic particles A-1>
100 parts of silicon dioxide particles as inorganic particles, 10 parts of the surface treatment agent represented by the above exemplary compound (3-1) (product name: KBM-5803, manufactured by Shin-Etsu Chemical Co., Ltd.), and 500 parts of toluene were stirred and mixed for 6 hours. . After that, toluene was distilled off under reduced pressure, and dried by heating at 130° C. for 2 hours to obtain inorganic particles (A-1) having a structure represented by the following formula (5) on the surface.

(In formula (5), the silicon-bonded oxygen atoms are bonded to the silicon dioxide particles.)
<Production Examples of Inorganic Particles A-2 to A-15>
Inorganic particles A-2 to A-15 were obtained in the same manner as in the production example of inorganic particles A-1, except that the type of inorganic particles and the type of surface treatment agent were changed as shown in Table 1. .

Structural formulas of Comparative Compounds 11-1 to 11-3 are shown below.

<Example 1>
<Support>
A cylindrical aluminum cylinder with a diameter of 29.9 mm, a length of 357.5 mm and a thickness of 0.7 mm was used as a support.

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

Next, a mixed solution of 73.5 parts by mass of methyl ethyl ketone and 73.5 parts by mass of 1-butanol was prepared. Then, polyvinyl butyral (trade name: S-Lec (registered trademark) B BM-1, manufactured by Sekisui Chemical Co., Ltd.) 15 parts by mass and blocked isocyanate (trade name: Sumidule 3175, manufactured by Sumitomo Bayer Urethane Co., Ltd.) 15 parts by mass of the above It was dissolved in the mixed solution.

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 in an atmosphere of 23° C. for 3 hours using a sand mill apparatus using glass beads with a diameter of 0.8 mm. After dispersion, the following materials were added and stirred to prepare an undercoat layer coating solution.
・ Silicone oil (trade name: SH28PA, manufactured by Dow Corning Toray Co., Ltd.) 0.01 parts by mass ・ Crosslinked polymethyl methacrylate (PMMA) particles (trade name: TECHPOLYMER (registered trademark) SSX-103, manufactured by Sekisui Plastics Co., Ltd., Average primary particle size: 3.1 µm) 5.6 parts by mass 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 give a film thickness of 18 µm. An undercoat layer was formed.

<Charge generation layer>
The following materials were placed in a sand mill using glass beads with a diameter of 1 mm, dispersed for 4 hours, and then 700 parts by mass of ethyl acetate was added to prepare a charge generation layer coating liquid.
・20 parts by mass of hydroxygallium phthalocyanine crystal (charge-generating substance) having strong peaks at 7.4° and 28.2° of Bragg angle 2θ±0.2° in CuKα characteristic X-ray diffraction ・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 formula (A) 0.2 parts by mass

Cyclohexanone 600 parts by mass This charge generation layer coating solution was dip-coated on the undercoat layer, and the resulting coating film was dried at 80° C. for 15 minutes to form a charge generation layer having a thickness of 0.18 μm.

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

(In the above formula (E), 0.95 and 0.05 are molar ratios (copolymerization ratios) in the compound.)
This first 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 first charge transport layer having a thickness of 18 μm.

<Second charge transport layer>
Next, 10 parts of the above inorganic particles A-1 were prepared and dissolved in 40 parts of 1-propanol. After that, it was dispersed with a high-pressure disperser (trade name: Microfluidizer M-110EH, manufactured by Microfluidics, Inc., USA). Thus, an inorganic particle dispersion liquid was obtained.

Next, the following materials were stirred and uniformly dispersed to prepare a coating liquid for the second charge transport layer.
- 100 parts of the hole-transporting compound represented by the above exemplary compound 2-28 - 300 parts of the above inorganic particle dispersion - Solvent: 60 parts of 1-propanol It was dip coated onto the transport layer and the resulting coating was dried at 50°C for 10 minutes. After that, in an atmosphere with an oxygen concentration of 50 ppm or less, while rotating the aluminum cylinder at a speed of 300 rpm, an electron beam irradiation apparatus was used with 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. was irradiated with an electron beam. After the electron beam irradiation, the surface of the coating film was quickly heated to 135° C. over 24 seconds using an induction heating device while maintaining the oxygen concentration of 50 ppm or less. Next, the aluminum cylinder was taken out into the atmosphere and heated at 100° C. for 12 minutes to form a second charge transport layer (surface layer) having a thickness of 5 μm.

The electron beam irradiation and heating are treatments for polymerizing and curing the coating film.

<Surface shape>
Next, a mold member (mold) was placed in a press-contact shape transfer processing apparatus, and the electrophotographic photoreceptor 1 was manufactured by performing surface processing on the electrophotographic photoreceptor before forming recesses.

A specific description will be given with reference to FIG. The mold shown in FIG. 4 is placed in a pressure contact shape transfer processing apparatus generally having a configuration including a mold 52, a pressure member 53, and a support member 54 shown in FIG. surface treatment. FIG. 4 is a diagram showing a mold used in Examples and Comparative Examples. FIG. 4(a) is a top view schematically showing the mold, and FIG. 4(b) is a schematic cross-sectional view of the protrusions of the mold in the axial direction of the electrophotographic photosensitive member 51 (in the SS' cross section of FIG. 4(a). cross-sectional view). FIG. 4(c) is a circumferential cross-sectional view of the projections of the mold of the electrophotographic photosensitive member 51 (a cross-sectional view taken along the line T-T' in FIG. 4(a)). In the mold shown in FIG. 4 used in the present disclosure, the maximum width (maximum width in the axial direction of the electrophotographic photosensitive member 51 when the projections on the mold are viewed from above) X was 50 μm. . Further, the maximum length (the maximum length in the circumferential direction of the electrophotographic photosensitive member 51 when the projections on the mold are viewed from above) Y is 75 μm, the area ratio is 56%, and the projections was 4 μm. Note that the area ratio is the ratio of the area of the projections to the entire surface of the mold when viewed from above. During processing, the temperatures of the electrophotographic photosensitive member 51 and the mold were controlled so that the surface temperature of the electrophotographic photosensitive member 51 was 120.degree. Then, while pressing the electrophotographic photoreceptor and the pressure member against the mold with a pressure of 7.0 MPa, the electrophotographic photoreceptor 51 is rotated in the circumferential direction, and the entire surface layer (peripheral surface) of the electrophotographic photoreceptor 51 is covered. A recess was formed. Thus, the electrophotographic photosensitive member was surface-treated.

The surface of the obtained electrophotographic photoreceptor was observed with a laser microscope (trade name: X-100, manufactured by KEYENCE CORPORATION) with a magnification of 50 times, and the depressions provided on the surface of the electrophotographic photoreceptor were observed. gone. At the time of observation, adjustments were made so that the electrophotographic photosensitive member was not tilted in the longitudinal direction, and that the apex of the arc of the electrophotographic photosensitive member was in focus in the circumferential direction. A square area with a side of 500 μm was obtained by connecting images obtained by magnifying observation using an image connection application. Then, for the obtained results, image processing height data was selected using attached image analysis software, and filter processing was performed using filter type median.

As a result of the observation, the depth of the recess was 2 μm, the width of the opening of the recess was 50 μm in the axial direction, the length of the opening of the recess was 75 μm in the circumferential direction, and the area was 140000 μm ² . The area is the area of the recess when the surface of the electrophotographic photosensitive member is viewed from above, and means the area of the opening of the recess.

[evaluation]
(Evaluation of light fatigue)
The produced electrophotographic photosensitive member 1 was mounted on the cyan station of a remodeled copier (trade name: imageRUNNER (registered trademark) ADVANCE C5255, manufactured by Canon Inc.) as an evaluation apparatus. The modified point of the apparatus was the point that it was made possible to change the charging setting and the amount of light.

Then, in an environment of 23° C./50% RH, the potential conditions of the charging device and the image exposing device are set so that the electrophotographic photosensitive member has a dark potential (Vd) of −700 V and a light potential (Vl) of −200 V. The initial potential of the electrophotographic photosensitive member was adjusted in advance.

Next, the attached electrophotographic photosensitive member 1 is taken out, and a light-shielding sheet having a rectangular hole of 15 mm in the rotational direction of the photosensitive member and 100 mm in the longitudinal direction of the photosensitive member is wound around the surface of the electrophotographic photosensitive member 1 . , 1500 lx, and exposed to neutral white light for 5 minutes. After that, the light-shielding sheet was removed from the electrophotographic photosensitive member 1, and it was mounted again on the cyan station of the evaluation apparatus, and a solid black image was output on the entire surface under the potential conditions set above.

Then, the electrophotographic photoreceptor 1 was taken out from the apparatus, and the surface potentials of the portion exposed to the daylight white light and the portion shielded from light were measured by the above operation, and the absolute value of the difference was used to evaluate the light fatigue. It was determined that the effects of the present disclosure were obtained when the absolute value was 15 V or less. Table 2 shows the evaluation results.

(Abrasion resistance evaluation)
First, the film thickness of the surface layer of the electrophotographic photoreceptor 1 was measured. Then, the electrophotographic photoreceptor 1 was attached to the cyan station of the evaluation apparatus described above. After that, in an environment of 23° C. and 50% RH, 100,000 sheets of A4 size paper were used, and an image having an image density of 10% was used to output images continuously on 100,000 sheets. After image output, the film thickness of the surface layer of the electrophotographic photoreceptor 1 was measured again, and the wear amount (μm) of the surface layer was confirmed and evaluated. Table 2 shows the evaluation results. An eddy current film thickness meter (Fischerscope, manufactured by Fisher Instruments) was used to measure the film thickness.

<Examples 2 to 21, Comparative Examples 1 to 4>
Except that the hole-transporting compound, the inorganic particle dispersion, the non-charge-transporting compound, and the solvent used in the step of forming the second charge-transporting layer in Example 1 were changed as shown in Table 2, the procedure was carried out. Electrophotographic photoreceptors 2 to 21 and 23 to 26 were produced in the same manner as in Example 1 and evaluated. Table 2 shows the evaluation results. Further, the non-charge-transporting compounds in Examples 2 to 7 were added when preparing the second charge-transporting layer coating solution.

<Example 22>
In Example 1, the second charge transport layer was formed on the charge generation layer without forming the first charge transport layer on the charge generation layer, and the coating solution for the second charge transport layer was The same operation as in Example 1 was performed, except that the amount of solvent during preparation was changed. An electrophotographic photoreceptor 22 was produced by this operation and evaluated. Table 2 shows the evaluation results.

The hole-transporting compound represented by Formula (F) and the hole-transporting compound represented by Formula (G) used in Comparative Examples are shown below.

REFERENCE SIGNS LIST 1 electrophotographic photosensitive member 2 shaft 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 guiding means 21 support 22 undercoat layer 23 charge generation layer 24 First charge transport layer 25 Second charge transport layer (surface layer)
51 electrophotographic photoreceptor 52 mold 53 pressure member 54 support member H maximum height of mold X maximum width of mold Y maximum length of mold

Claims (9)

An electrophotographic photoreceptor having a support and a photosensitive layer on the support,
The surface layer of the electrophotographic photoreceptor is
(A) a hole-transporting compound having a chain polymerizable group; and (B) inorganic particles surface-treated with a compound represented by the following formula (1);
An electrophotographic photoreceptor, which is a polymer film of a composition containing

(In formula (1), Ln is a straight-chain alkylene group having 6 or more and 10 or less carbon atoms. R ¹ to R ³ are each independently an alkoxy group or an alkyl group, and R ¹ to R ³ is an alkoxy group.Fn is a chain polymerizable group that copolymerizes with the chain polymerizable group of the hole-transporting compound.) 2. The electrophotographic photoreceptor according to claim 1, wherein said inorganic particles are silica particles. 3. The electrophotographic photoreceptor according to claim 1, wherein the chain polymerizable group possessed by the hole-transporting compound is at least one of an acryloyloxy group and a methacryloyloxy group. 4. The electrophotographic photoreceptor according to claim 1, wherein said Fn is at least one of an acryloyloxy group and a methacryloyloxy group. 5. The electrophotographic photoreceptor according to claim 1, wherein the hole-transporting compound has two or more chain polymerizable groups. 6. The electrophotographic photoreceptor according to any one of claims 1 to 5, wherein the content of the inorganic particles is 30.0 to 85.0% by mass with respect to the mass of the hole-transporting compound. the photosensitive layer has a charge generation layer, a first charge transport layer and a second charge transport layer in this order;
7. The electrophotographic photoreceptor according to claim 1, wherein the second charge transport layer is the surface layer. A process cartridge having the electrophotographic photoreceptor according to any one of claims 1 to 7,
The process cartridge integrally supports at least one means selected from the group consisting of charging means, exposure means, development means, and transfer means, and is detachable from the main body of the electrophotographic apparatus. . An electrophotographic apparatus comprising the electrophotographic photoreceptor according to any one of claims 1 to 7,
An electrophotographic apparatus comprising charging means, exposure means, developing means and transfer means.

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