JP7263026B2 - Electrophotographic photoreceptor manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing an electrophotographic photoreceptor.

In recent years, the diversification of electrophotographic apparatus users has progressed, and higher image quality and higher stability than conventional ones are required for output images.

In order to maintain stable image quality, the surface of the electrophotographic photoreceptor must have excellent mechanical durability so that the surface of the electrophotographic photoreceptor does not become worn or scratched even after repeated printing over a long period of time. It is important not to In order to improve the mechanical durability of the surface of the electrophotographic photoreceptor, a protective layer containing a hard resin is provided as the surface layer of the electrophotographic photoreceptor, and a resin having high mechanical durability is used for the surface layer. Techniques such as dispersing a filler in the surface layer are generally used.

Properties required for the coating liquid for forming each layer of the electrophotographic photoreceptor include the following. Good dissolution of solutes, no change in properties due to storage, and no significant damage to already formed underlayers. In particular, in the case of a paint in which fine particles are dispersed, it is important that the coatability is good and that the coating film is not defective due to aggregation of the particles.

Patent Document 1 discloses a technique for improving the abrasion resistance of the surface of an electrophotographic photoreceptor. Techniques relating to electrophotographic photoreceptors having layers have been disclosed.

Further, Patent Document 2 discloses the following technique for maintaining good cleanability and improving durability of the surface of an electrophotographic photoreceptor. That is, the metal oxide fine particles dispersed in the protective layer as the surface layer of the electrophotographic photosensitive member are treated with two kinds of surface treatment agents. Furthermore, a part of the metal oxide fine particles having these two types of surface treatment agents is retained on the surface of the fluororesin fine particles. This suppresses aggregation of the fluororesin fine particles in the protective layer and improves the dispersibility. Furthermore, by fixing the fluororesin fine particles to the binder resin via the metal oxide fine particles, the fluororesin fine particles are prevented from coming off from the protective layer.

JP 2017-58524 A JP 2017-125946 A

As described above, it is important to reduce wear on the surface of the electrophotographic photoreceptor in order to stably maintain image quality during use.

However, according to studies by the present inventors, when the electrophotographic photoreceptors described in Patent Documents 1 and 2 are used in order to reduce wear on the surface of the electrophotographic photoreceptor, the aggregation of the resin particles reduces the image quality. It has been found that defects may occur.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a method for producing an electrophotographic photoreceptor using a surface layer coating liquid for forming a surface layer that suppresses the occurrence of image defects.

A method for producing an electrophotographic photoreceptor according to the present invention is a method for producing an electrophotographic photoreceptor having a support and a surface layer , wherein a coating for the surface layer is used to form the surface layer. a step of applying a liquid , wherein the surface layer coating liquid contains resin particles (β) having inorganic particles (α) on their surfaces, and the average particle size (Lα) of the inorganic particles (α) is 5 nm or more and 50 nm or less, the average particle size (Lβ) of the resin particles (β) is 0.1 μm or more and 5.0 μm or less , and the inorganic particles (α) are selected from the group consisting of silica and alumina. It is characterized by being treated with silicone oil or a silane coupling agent .

According to the present invention, it is possible to provide a method for producing an electrophotographic photoreceptor using a surface layer coating liquid for forming a surface layer that suppresses the occurrence of image defects.

1 is a diagram showing an example of a schematic configuration of an electrophotographic apparatus having a process cartridge provided with an electrophotographic photoreceptor according to the present invention; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to preferred embodiments.
A method for producing an electrophotographic photoreceptor according to the present invention is a method for producing an electrophotographic photoreceptor having a support and a surface layer , wherein a coating for the surface layer is used to form the surface layer. a step of applying a liquid , wherein the surface layer coating liquid contains resin particles (β) having inorganic particles (α) on their surfaces, and the average particle size (Lα) of the inorganic particles (α) is 5 nm or more and 50 nm or less, the average particle size (Lβ) of the resin particles (β) is 0.1 μm or more and 5.0 μm or less , and the inorganic particles (α) are selected from the group consisting of silica and alumina. It is characterized by being treated with silicone oil or a silane coupling agent .

According to the studies of the present inventors, in the configuration of Patent Document 1 or 2, the resin particles and the inorganic particles exist independently of each other in the coating liquid for the surface layer. It has been found that image failure may occur as a film defect.

In order to solve the problems that have arisen in the prior art, the present inventors paid attention to the relationship between the resin particles and the inorganic particles in the coating liquid and conducted studies. As a result, resin particles (β) having an average particle size (Lα) of 0.1 μm or more and 5.0 μm or less having inorganic particles (α) having an average particle size (Lα) of 5 nm or more and 50 nm or less on the surface were added to the coating liquid. It was found that the inclusion of Ni can reduce the problems that have occurred in the prior art.

The mechanism of how the configuration of the present invention can reduce the problems of the prior art is considered as follows.
A coating liquid containing resin particles and inorganic particles may cause aggregation of particles due to the passage of time, the storage environment, and the like. As a result, the agglomerated particles adhere to the surface of the electrophotographic photosensitive member during the formation of the coating film, resulting in image defects.

According to the configuration of the present invention, by previously supporting the inorganic particles on the surfaces of the resin particles and incorporating them into the coating liquid, aggregation between the resin particles is suppressed to form a more stable coating liquid. This prevents adherence of agglomerated particles to the surface of the electrophotographic photoreceptor when forming a coating film, thereby suppressing the occurrence of image defects.

<Inorganic particles (α)>
The inorganic particles (α ) are particles of a compound selected from the group consisting of silicon oxide (silica, SiO ₂ ) and aluminum oxide (alumina, Al ₂ O ₃ ) from the viewpoints of hardness, insulation and light transmission. There is . Also, the inorganic particles (α) are treated with silicone oil or a silane coupling agent.
The average particle size (Lα) of the inorganic particles (α) is 5 nm or more and 50 nm or less.

式（１）および（２）中、Ｒ^１～Ｒ^３は、それぞれ独立に、アルコキシ基またはアルキル基を示し、Ｒ^１～Ｒ^３の少なくとも２つはアルコキシ基である。また、Ｒ^４は、ビニル基、１－メチルビニル基、アクリロイルオキシ基またはメタクリロイルオキシ基である。Ｒ^５はアクリロイルオキシ基またはメタクリロイルオキシ基を示し、ｎは１以上６以下の整数である。 From the viewpoint of affinity with the resin particles, the surfaces of the inorganic particles are preferably treated with silicone oil or at least one compound selected from the compounds represented by structural formulas (1) and (2).

In formulas (1) and (2), R ¹ to R ³ each independently represent an alkoxy group or an alkyl group, and at least two of R ¹ to R ³ are alkoxy groups. R ⁴ is a vinyl group, 1-methylvinyl group, acryloyloxy group or methacryloyloxy group. ^R5 represents an acryloyloxy group or a methacryloyloxy group, and n is an integer of 1 or more and 6 or less.

Specific examples of the compounds represented by the structural formulas (1) and (2) include those represented by the following structural formulas (P-1) to (P-21).

<Resin particles (β)>
The resin particles (β) are selected from melamine resins such as polymethyl methacrylate resin (PMMA), melamine-formaldehyde condensed resin and melamine-benzoguanamine-formaldehyde condensed resin, benzoguanamine resin, styrene acrylic resin, silicone resin and fluorine resin. Particles of resin can be used. These resins may constitute particles alone, or two or more of them may be mixed to form particles. As the resin particles (β), it is preferable to use resin particles selected from PMMA, melamine-formaldehyde condensed resins and fluororesins.

The average particle size (Lβ) of the resin particles (β) is 0.1 μm or more and 5.0 μm or less. The average particle size (Lβ) of the resin particles (β) is more preferably 0.1 μm or more and 1.5 μm or less.

<Resin Particles (β) Having Inorganic Particles (α) on Their Surfaces>
The method of adhering the inorganic particles (α) to the surface of the resin particles (β) may be, for example, by mixing the resin particles (β) and the inorganic particles (α) and using a powder mixer such as a Henschel mixer. , a coffee mill or the like may be used. Further, a polymerizable functional group is imparted to the surface of each of the resin particles (β) and the inorganic particles (α), and the polymerizable functional groups imparted to the respective particle surfaces are allowed to react with each other to allow the particles to adhere to each other. I don't mind.

A powder mixer such as a Henschel mixer and a method of attaching inorganic particles and resin particles by physical impact such as a coffee mill can reliably support the inorganic particles on the surface of the resin particles, so the effect of the present invention is obtained. is preferable in order to efficiently obtain
When the particles are attached to each other by reacting the polymerizable functional groups imparted to the surface of each particle, as described above, after the particles are attached to each other by physical impact, the polymerizable functional groups is preferably reacted.
In order to obtain a higher effect of the present invention, it is preferable that the inorganic particles (α) or surface-treated inorganic particles (α) are directly supported by the resin particles (β).
Moreover, the coverage of the resin particles (β) with the inorganic particles (α) is preferably 40% or more.

[Electrophotographic photoreceptor]
An electrophotographic photoreceptor manufactured by the manufacturing method according to the present invention is characterized by having a support and a surface layer.

Examples of the method for producing the electrophotographic photoreceptor of the present invention include 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 layer will be described below.
<Support>
In the present invention, the electrophotographic photoreceptor has a support. In the present invention, the support is preferably an electrically conductive support. 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 also be imparted to the resin or glass by treatment 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 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.
Moreover, when a metal oxide is used 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 resins include polyester resins, polycarbonate resins, polyvinyl acetal resins, acrylic resins, silicone resins, epoxy resins, melamine resins, polyurethane resins, phenol resins, and alkyd resins.
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 invention, an undercoat layer may be provided on the support or the 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.

Further, the undercoat layer may further contain an electron transporting substance, a metal oxide, a metal, a conductive polymer, or the like for the purpose of enhancing electrical properties. Among these, electron transport substances and metal oxides are preferably used.
Examples of electron-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. . An electron transporting substance having a polymerizable functional group may be used as the electron transporting substance, and an undercoat layer may be formed as a cured film by copolymerizing the electron 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 thickness of the undercoat layer is preferably from 0.1 μm to 50 μm, more preferably from 0.2 μm to 40 μm, and particularly preferably from 0.3 μm to 30 μm.

The undercoat layer can be formed by preparing an undercoat layer coating solution containing each of the materials and solvents described above, 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.
When the electrophotographic photoreceptor does not have a protective layer described later, (1) in the laminated photosensitive layer, the charge-transporting layer is the surface layer in the present invention, and (2) in the single-layer photosensitive layer, the photosensitive layer is the photosensitive layer in the present invention. It is the surface layer.

(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.

Resins include polyester resins, polycarbonate resins, polyvinyl acetal resins, polyvinyl butyral resins, acrylic resins, silicone resins, epoxy resins, melamine resins, polyurethane resins, phenol resins, polyvinyl alcohol resins, cellulose resins, polystyrene resins, and polyvinyl acetate resins. , polyvinyl chloride resin, and the like. 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 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.

(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, 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, silica particles, alumina particles, boron nitride particles. etc.

The average film 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-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.
When the charge transport layer is the surface layer in the present invention, the coating liquid for the charge transport layer is the coating liquid for the surface layer in the present invention as described above, and resin particles having inorganic particles (α) on their surfaces. (β) is contained.

(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 binder resin and a solvent, forming a coating film, and drying the coating solution. can be formed with The charge-generating substance, charge-transporting substance, and binder resin are the same as those exemplified in the above “(1) Laminated photosensitive layer”.
When the photosensitive layer is the surface layer in the present invention, the photosensitive layer coating liquid is the surface layer coating liquid in the present invention, and resin particles (β ).

<Protective layer>
In the present invention, the electrophotographic photoreceptor may have a protective layer on the photosensitive layer. Durability can be improved by providing a protective layer.
When the electrophotographic photoreceptor has a protective layer, the protective layer is the surface layer in the invention. That is, the protective layer contains resin particles (β) having inorganic particles (α) on their surfaces.

Moreover, the protective layer preferably contains conductive particles and/or a charge-transporting substance, and a resin.
Conductive particles include particles of metal oxides such as titanium oxide, zinc oxide, tin oxide, and indium oxide.
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. Among these, triarylamine compounds and benzidine compounds are preferred.
Examples of resins include polyester resins, acrylic resins, phenoxy resins, polycarbonate resins, polystyrene resins, phenol resins, melamine resins, and epoxy resins. Among them, polycarbonate resins, polyester resins, and acrylic resins are preferred.

Alternatively, the protective layer may be formed as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group. The reaction at that time includes thermal polymerization reaction, photopolymerization reaction, radiation polymerization reaction, and the like. Examples of the polymerizable functional group possessed by the monomer having a polymerizable functional group include an acrylic group and a methacrylic group. A material having charge transport ability may be used as the monomer having a polymerizable functional group.

The protective layer contains additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, lubricity imparting agents, wear resistance improvers, etc., in addition to the inorganic particles and resin particles related to the present invention. good too. Specifically, 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, silica particles, alumina particles, boron nitride particles. etc.

The average film thickness of the protective layer is preferably 0.5 μm or more and 10 μm or less, and more preferably 1 μm or more and 7 μm or less.

The protective layer can be formed by preparing a protective layer coating liquid containing each of the materials and solvents described above, forming a coating film thereon, and drying and/or curing the coating film. The protective layer coating liquid is the surface layer coating liquid in the present invention, and contains the resin particles (β) having the inorganic particles (α) on the surface as described above.

Solvents used in the coating liquid include alcohol solvents, ketone solvents, ether solvents, sulfoxide solvents, ester solvents, and aromatic hydrocarbon solvents.

[Process cartridge, electrophotographic device]
A process cartridge having an electrophotographic photosensitive member manufactured by the manufacturing method according to the present invention is characterized as follows. That is, the process cartridge integrally supports the electrophotographic photosensitive member described above and at least one means selected from the group consisting of charging means, developing means, transfer means and cleaning means. It is removable.

Further, the electrophotographic apparatus of the present invention is characterized by having the electrophotographic photosensitive member, charging means, exposure means, developing means and transfer means described above.

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 cleaning means 9 is not separately provided, and the deposits are removed by developing means or the like. The electrophotographic apparatus may have a charge removing mechanism that removes charges from the surface of the electrophotographic photosensitive member 1 with pre-exposure light 10 from a pre-exposure unit (not shown). Also, a guide means 12 such as a rail may be provided for attaching and detaching the process cartridge 11 to and from the main body of the electrophotographic apparatus.

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

The present invention will be described in more detail below using examples and comparative examples. The present invention is by no means limited by the following examples as long as the gist thereof is not exceeded. In the description of the following examples, "parts" are based on mass unless otherwise specified. Photoreceptors 10 to 13, 19, 32, and 33 in the following description are reference examples.

(Production example of particles S1)
A 2 L stirred autoclave was charged with 100 parts by weight of untreated silica having an average particle size of 40 nm and heated to 200° C. while being fluidized by stirring. While maintaining the fluidized state, the inside of the autoclave was replaced with nitrogen gas and the reactor was sealed. Thereafter, while stirring the silica, dimethylsilicone oil (viscosity = 50 mm ² /s) was sprayed, and stirring was continued for 30 minutes. The amount of dimethyl silicone oil (viscosity = 50 mm ² /s) to be sprayed was adjusted so that the amount of silica after treatment was 20 parts by mass. After that, the temperature was raised to 300° C. while stirring, and the mixture was further stirred for 2 hours. Silica was taken out from the autoclave to obtain particles S1 as inorganic particles (α). Details of the particles S1 are shown in Table 1.

(Production example of particles S2)
Particles as the inorganic particles (α) were produced in the same manner as in the production example of the particles S1 except that the amounts of silica and silicone oil were changed as shown in Table 1. The obtained particles were designated as "S2". Details are shown in Table 1.

(Production example of particles S3)
100 parts of silica (average primary particle size: 40 nm) was stirred and mixed with 500 parts of toluene, 0.8 parts of octyltriethoxysilane (trade name: KBE3083, manufactured by Shin-Etsu Chemical Co., Ltd.) was added, and the mixture was stirred for 6 hours. .
Thereafter, toluene was distilled off under reduced pressure, dried by heating at 140° C. for 6 hours, and surface-treated to obtain particles S3 as inorganic particles (α). Details are shown in Table 1.

(Production example of particles S4 and particles S5)
Particles were produced in the same manner as in Particle S3 Production Example, except that the type and amount of silica and surface treatment agent were changed as shown in Table 1. The obtained particles as inorganic particles (α) were referred to as “particles S4 and particles S5”. Details are shown in Table 1.

The surface treatment agent compound P-10 used in the production of the particles S5 is a compound represented by the above structural formula (P-10).

(Production example of particle A1)
100 parts of aluminum oxide particles (average primary particle diameter: 10 nm, specific surface area: 150 m ² /g) are stirred and mixed with 500 parts of toluene, and 1 part of silicone oil (trade name: KBE3083, manufactured by Shin-Etsu Chemical Co., Ltd.) is added. 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 aluminum oxide particles A1. Details are shown in Table 1.

(Production example of particles A2)
100 parts of aluminum oxide particles (average primary particle diameter: 18 nm, specific surface area: 65 m ² /g) were stirred and mixed with 500 parts of toluene. 8 parts were added and stirred for 6 hours.
Thereafter, toluene was distilled off under reduced pressure, dried by heating at 140° C. for 6 hours, and surface-treated to obtain particles A2 as inorganic particles (α). Details are shown in Table 1.

(Production example of particles A3)
100 parts of aluminum oxide particles (average primary particle diameter: 18 nm, specific surface area: 65 m ² /g) were stirred and mixed with 500 parts of toluene, and octyltriethoxysilane (trade name: KBE3083, manufactured by Shin-Etsu Chemical Co., Ltd.)1. 1 part was added and stirred for 6 hours.
Thereafter, toluene was distilled off under reduced pressure, dried by heating at 140° C. for 6 hours, and surface-treated to obtain particles A3 as inorganic particles (α). Details are shown in Table 1.

(Production example of particles A4)
100 parts of aluminum oxide particles (average primary particle diameter: 18 nm, specific surface area: 65 m ² /g) were stirred and mixed with 500 parts of toluene, 1.03 parts of compound P-10 was added, and the mixture was stirred for 6 hours.
Thereafter, toluene was distilled off under reduced pressure, dried by heating at 140° C. for 6 hours, and surface-treated to obtain particles A4 as inorganic particles (α). Details are shown in Table 1.

(Production Example of Composite Particle H1)
200 parts of particles S1 and 100 parts of melamine-formaldehyde condensed resin particles (trade name: Eposter S6, manufactured by Nippon Shokubai Co., Ltd.) having an average particle diameter of 0.4 μm are mixed and stirred for 10 seconds in a coffee mill. Composite particles H1 were obtained by repeating the process several times.
The coverage of the obtained composite particles H1 was determined as follows. First, the total surface area of resin particles H1 was calculated from the weight, specific gravity and average particle size of resin particles H1. Further, the covered area per inorganic particle is calculated from the weight, specific gravity and average particle diameter of the inorganic particles, and the total covered area of the inorganic particles is obtained from the covered area per inorganic particle and the total number of inorganic particles. rice field. From the total surface area of resin particles H1 and the total covered area of inorganic particles, (total covered area of inorganic particles/total surface area of resin particles)×100 was calculated as the coverage of composite particles H1.

(Production Examples of Composite Particles H2 to H33)
The type and amount of surface-treated inorganic particles used, the type and amount of resin particles used, and the total treatment time for mixing the surface-treated inorganic particles and resin particles were changed to the conditions shown in Table 2. bottom. Otherwise, composite particles were obtained in the same manner as in the production example of composite particles H1. The obtained composite particles were designated as “composite particles H2 to H33”. For composite particles H2 to H33 thus obtained, the coverage was determined in the same manner as for composite particle H1.

(Production example of protective layer coating liquid 1)
70 parts of a hole-transporting compound represented by the following structural formula (3), 5 parts of particles H1, 30 parts of 1,1,2,2,3,3,4-heptafluorocyclopentane and 30 parts of 1-propanol They were mixed to prepare a protective layer coating solution. The obtained protective layer coating liquid was designated as "protective layer coating liquid 1". Table 3 shows the types and amounts of the composite particles used in the preparation of Protective Layer Coating Liquid 1.

(Production Examples of Protective Layer Coating Liquids 2 to 33)
The type and amount of composite particles used were changed to the conditions shown in Table 3. Otherwise, the protective layer coating liquid was obtained in the same manner as in the production example of the protective layer coating liquid 1. The protective layer coating liquids thus obtained were designated as "protective layer coating liquids 2 to 33".

(Manufacturing example of protective layer coating liquid 101)
The following materials were prepared.
・70 parts of a hole-transporting compound represented by the structural formula (3) ・10.5 parts of particles S1 ・Melamine-formaldehyde condensed particles with an average particle size of 0.4 μm (trade name: Eposter S6, Nippon Shokubai Co., Ltd.) 21 parts of 1,1,2,2,3,3,4-heptafluorocyclopentane, 30 parts of 1-propanol These were mixed to prepare a protective layer coating solution. The obtained protective layer coating liquid was designated as "protective layer coating liquid 101".

(Manufacturing example of protective layer coating liquid 102)
The following materials were prepared.
・70 parts of a hole-transporting compound represented by the structural formula (3) ・1.6 parts of particles S1 ・Melamine-formaldehyde condensed particles with an average particle size of 0.4 μm (trade name: Eposter S6, Nippon Shokubai Co., Ltd.) 3.5 parts of 1,1,2,2,3,3,4-heptafluorocyclopentane and 30 parts of 1-propanol These were mixed to prepare a protective layer coating solution. The obtained protective layer coating liquid was designated as "protective layer coating liquid 102".

(Manufacturing example of protective layer coating liquid 103)
Antimony-doped tin oxide (hereinafter referred to as ATO) microparticles (average particle diameter: 10 nm to 15 nm, trade name: T-1, manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd.) were used as raw material inorganic particles.
The following materials were prepared in such amounts that the mixing ratio with respect to the ATO fine particles was the value shown below.
・ 1H, 1H, 2H, 2H-nanofluorohexyltrimethoxysilane (trade name: T2918, manufactured by Tokyo Chemical Industry Co., Ltd.), which is a fluorine-based silane coupling agent, 10% by mass
・ Octenyltrimethoxysilane (trade name: KBM1083, manufactured by Shin-Etsu Silicone Co., Ltd.), which is a polymerizable silane coupling agent, 4% by mass
As a dispersion solvent, 200% by mass of IPA (99.5% special reagent of isopropyl alcohol, manufactured by Kishida Chemical Co., Ltd.) was used. These materials were mixed and dispersed using a bead mill to prepare an ATO fine particle dispersion. The dispersion time was 90 hours.

Next, the following materials were prepared.
・As a polymerization initiator, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (trade name: Irgacure 907, manufactured by BASF Japan Ltd.) 10 parts by mass ・As a photocurable resin, Polyfunctional fluorine-modified acrylic resin (trade name: ACU-3, manufactured by Kanto Denka Kogyo Co., Ltd.) 100 parts by weight Isopropyl alcohol (IPA: special grade reagent 99.5%, manufactured by Kishida Chemical Co., Ltd.) 150 parts by weight as a dispersion solvent・As fluororesin fine particles, polytetrafluoroethylene (PTFE) fine particles (average particle size: 2.3 μm, maximum particle size: 4.62 μm, trade name: KTL1N, manufactured by Kitamura Co., Ltd.) 30 parts by mass Photocuring properties of PTFE fine particles The mixing ratio with respect to resin was 30% by mass. These materials were mixed and added to 100 parts by mass of the above ATO fine particle dispersion. After that, the mixed liquid is mixed and stirred under light shielding, and the mixed liquid is irradiated with ultrasonic waves generated from an ultrasonic oscillator (oscillation frequency: 40 kHz, ultrasonic output: 50 W) for 5 minutes to disperse the components in the mixed liquid. It was dispersed in a solvent to prepare protective layer coating liquid 103 .

<Production of Electrophotographic Photoreceptor>
・Manufacturing example of electrophotographic photoreceptor (hereinafter simply referred to as photoreceptor) (Manufacturing example of photoreceptor 1)
An aluminum cylinder with a diameter of 30 mm and a length of 357.5 mm was used as a support (cylindrical support).

Next, the following materials were prepared.
・ Barium sulfate particles coated with tin oxide (trade name: Pastran PC1, manufactured by Mitsui Mining & Smelting Co., Ltd.) 60 parts ・ Titanium oxide particles (trade name: TITANIX JR, manufactured by Tayca Co., Ltd.) 15 parts ・ Resol type Phenolic resin (trade name: Phenolite J-325, manufactured by DIC Corporation, solid content 70% by mass) 43 parts Silicone oil (trade name: SH28PA, manufactured by Dow Corning Toray Co., Ltd.) 0.015 parts Silicone Resin particles (trade name: Tospearl 120, manufactured by Momentive Performance Materials Japan LLC) 3.6 parts, 50 parts of 2-methoxy-1-propanol, and 50 parts of methanol These are placed in a ball mill and dispersed for 20 hours. By doing so, a coating liquid for a conductive layer was prepared. This conductive layer coating solution was applied onto a support by dip coating, and the resulting coating film was cured by heating at 140° C. for 1 hour to form a conductive layer having a thickness of 15 μm.

Next, the following materials were prepared.
10 parts of copolymerized nylon (trade name: Amilan CM8000, manufactured by Toray Industries, Inc.) 30 parts of methoxymethylated 6 nylon resin (trade name: Torezin EF-30T, manufactured by Teikoku Chemical Co., Ltd.), 400 parts of methanol A coating liquid for an undercoat layer was prepared by dissolving in a mixed solvent of 200 parts of /n-butanol. This undercoat layer coating liquid was applied onto the conductive layer by dip coating, and the resulting coating film was dried at 100° C. for 30 minutes to form an undercoat layer having a thickness of 0.45 μm.

・ポリビニルブチラール（商品名：エスレックＢＸ－１、積水化学工業（株）製）１０部
・シクロヘキサノン６００部
これらを、直径１ｍｍガラスビーズを用いたサンドミルに入れた。そして、４時間分散処理した後、酢酸エチル７００部を加えることによって、電荷発生層用塗布液を調製した。この電荷発生層用塗布液を下引き層上に浸漬塗布し、得られた塗膜を１５分間８０℃で乾燥させることによって、膜厚０．１７μｍの電荷発生層を形成した。 Next, the following materials were prepared.
・20 parts of a crystalline hydroxygallium phthalocyanine crystal (charge-generating substance) having strong peaks at 7.4° and 28.2° of 2θ±0.2° of 2θ±0.2° in CuKα characteristic X-ray diffraction ・The following structural formula (A ) 0.2 parts of a calixarene compound represented by

· Polyvinyl butyral (trade name: S-lec BX-1, manufactured by Sekisui Chemical Co., Ltd.) 10 parts · Cyclohexanone 600 parts These were placed in a sand mill using glass beads with a diameter of 1 mm. After dispersion treatment for 4 hours, 700 parts of ethyl acetate was added to prepare a charge generation layer coating liquid. This charge generation layer coating liquid was applied onto the undercoat layer by dip coating, and the resulting coating film was dried at 80° C. for 15 minutes to form a charge generation layer having a thickness of 0.17 μm.

Next, the following materials were prepared.
- 30 parts of a compound represented by the following structural formula (B) (charge transport material)
- 60 parts of a compound represented by the following structural formula (C) (charge transport material)
- 10 parts of a compound represented by the following structural formula (D) (charge transport material)
Polycarbonate resin (trade name: Iupilon Z400, manufactured by Mitsubishi Engineering-Plastics Co., Ltd., bisphenol Z-type polycarbonate) 100 parts Polycarbonate having two structural units represented by the following structural formula (E) (viscosity average molecular weight Mv: 20000) 0.02 part These were mixed and dissolved in 271 parts of o-xylene, 256 parts of methyl benzoate and 272 parts of dimethoxymethane (methylal), and dip-coated on the charge generation layer. By drying the obtained coating film at 120° C. for 50 minutes, a charge transport layer having a thickness of 18 μm was formed.

Next, the protective layer coating solution 1 was dip-coated on the charge transport layer, and the resulting coating film was dried at 50° C. for 5 minutes. After drying, the coating film was irradiated with an electron beam for 1.6 seconds under conditions of an acceleration voltage of 60 kV and an absorption dose of 8000 Gy in a nitrogen atmosphere. The oxygen concentration from the electron beam irradiation to the heat treatment for 1 minute was 20 ppm. After that, the temperature was raised from 25° C. to 110° C. over 10 seconds in a nitrogen atmosphere. Next, heat treatment was performed for 10 minutes in a drying oven at 100° C. in the atmosphere to form a protective layer (surface layer) having a thickness of 5 μm. The resulting photoreceptor was referred to as "photoreceptor 1".

(Manufacturing Examples of Photoreceptors 2 to 33 and Photoreceptors 101 to 103)
A photoreceptor was produced in the same manner as in Photoreceptor 1 except that the type of protective layer coating liquid used and the film thickness of the protective layer were changed as shown in Table 3. The obtained photoreceptors were referred to as "Photoreceptor 2 to Photoreceptor 33" and "Photoreceptor 101 to Photoreceptor 103".

[evaluation]
(Evaluation of Photoreceptor)
Each of the photoreceptors prepared above was mounted on a cyan station of a modified machine of an electrophotographic apparatus (copier) manufactured by Canon Inc. (trade name: imageRUNNER ADVANCE C5560) as an evaluation apparatus. Subsequently, under an environment of 10° C./5% RH, the 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 photosensitive member was adjusted in advance.
After that, three A3 halftone images were output under the above conditions, and the images were evaluated. The evaluation rank was set as follows.
A: No dots on the image B: Within 2 dots of 0.3 mm < φ ≤ 0.5 mm on the image C: Within 3 dots of 0.3 mm < φ ≤ 0.8 mm on the image D : Five or more spots appearing in the image can be confirmed. Table 3 shows the results.

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 guide means

Claims (4)

A method for producing an electrophotographic photoreceptor comprising a support and a surface layer , comprising:
a step of applying a surface layer coating liquid to form the surface layer;
The surface layer coating liquid contains resin particles (β) having inorganic particles (α) on the surface,
The average particle size (Lα) of the inorganic particles (α) is 5 nm or more and 50 nm or less,
The average particle diameter (Lβ) of the resin particles (β) is 0.1 μm or more and 5.0 μm or less ,
The inorganic particles (α) are particles of a compound selected from the group consisting of silica and alumina, and are treated with silicone oil or a silane coupling agent.
A method for producing an electrophotographic photoreceptor, characterized by: 2. The method for producing an electrophotographic photoreceptor according to claim 1 , wherein the resin particles ([beta]) have an average particle size (L[beta]) of 0.1 [mu]m or more and 1.5 [mu]m or less. 3. The method for producing an electrophotographic photoreceptor according to claim 1 , wherein the resin particles (β) are resin particles selected from the group consisting of PMMA, melamine-formaldehyde condensed resin particles and fluororesins. 4. The method for producing an electrophotographic photoreceptor according to claim 1, wherein the inorganic particles (α) cover the resin particles (β) by 40 % or more .

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