JP2012189959A - Electrophotographic photoreceptor and manufacturing method thereof, image formation device, process cartridge, and hollow metal oxide particle and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor which suppresses the occurrence of an unintended minute dark dot on an image in its repeated use.SOLUTION: An electrophotographic photoreceptor 101 includes a conductive support 102, an undercoat layer 104 arranged on the conductive support and including hollow metal oxide particles comprising hollow particles composed of metal oxide and an accepting compound adhered onto the surface thereof, and a binder resin, and a photosensitive layer 103 arranged on the undercoat layer.

Description

  The present invention relates to an electrophotographic photosensitive member and a manufacturing method thereof, an image forming apparatus, a process cartridge, and hollow metal oxide particles and a manufacturing method thereof.

2. Description of the Related Art An image forming apparatus (electrophotographic apparatus) using an electrophotographic system is known as an image forming apparatus such as a copying machine or a printer that forms a color or monochrome image.
An electrophotographic photosensitive member (hereinafter sometimes referred to as a “photosensitive member”) used in an electrophotographic image forming apparatus is less expensive than man-made inorganic photoconductors and is manufacturable and discarded. Organic photoconductors using organic photoconductive materials having excellent advantages in terms of their properties are becoming mainstream. Among them, the functionally separated type organic photoreceptor in which a charge generation layer that generates charges upon exposure and a charge transport layer that transports charges is laminated is excellent in terms of electrophotographic characteristics, and various proposals have been made. It has been put into practical use.

For example, in Patent Document 1, in an electrophotographic photosensitive member in which at least an undercoat layer and a photosensitive layer are sequentially laminated on a conductive support, the undercoat layer has at least hollow particles, a metal oxide, and a binder resin. An electrophotographic photosensitive member characterized by comprising:
In Patent Document 2, a conductive layer is provided on an insulating film, and a polymer binder, insulating particles, and conductive fine particles having a specific gravity in the range of 0.8 to 0.9 (for example, a surface) An electrostatic recording film provided with a dielectric layer made of inorganic fine particles or organic polymer fine particles having a hollow structure coated with a conductive material is disclosed.

JP 2008-292553 A Japanese Patent Laid-Open No. 10-319612

  SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photosensitive member in which minute black spots that are not intended during repeated use are suppressed from being generated in an image.

The invention of claim 1
A conductive support;
An undercoating layer that is disposed on the conductive support and includes hollow metal oxide particles and a binder resin in which an acceptor compound is attached to the surface of the hollow particles composed of a metal oxide;
A photosensitive layer disposed on the undercoat layer;
An electrophotographic photosensitive member having:
The invention of claim 2
The electrophotographic photoreceptor according to claim 1, wherein the metal oxide is one or more metal oxides selected from the group consisting of titanium oxide, zinc oxide, aluminum oxide, silicon oxide, tin oxide, and zirconium oxide.
The invention of claim 3
The electrophotographic photoreceptor according to claim 1, wherein the acceptor compound is at least one compound selected from an anthraquinone compound and a perylene compound.
The invention of claim 4
The electrophotographic photoreceptor according to any one of claims 1 to 3, wherein the acceptor compound is at least one compound represented by the following general formula (I) or (II).

(In the formula (I), R ^{1 to} R ⁸ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, an amino group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl. Group or carboxyl group.)

(In the formula (II), R ^{a to} R ^b are each independently a hydrogen atom, a halogen atom, a hydroxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a nitro group, a cyano group, an amino group, Or a carboxyl group.)
The invention of claim 5
The electrophotographic photoreceptor according to claim 1, wherein the acceptor compound is at least one compound represented by the following general formula (2) or (3).


(In Formula (2), R ⁹ and R ¹⁰ each independently represents a substituted or unsubstituted alkylene group.)

(In Formula (3), R ¹¹ and R ¹² each independently represent a substituted or unsubstituted alkylene group, and R ¹³ and R ¹⁴ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a substituted or unsubstituted group. An alkyl group, a substituted or unsubstituted alkoxy group, a nitro group, a cyano group, an amino group, or a carboxyl group;
The invention of claim 6
At least the electrophotographic photoreceptor according to any one of claims 1 to 5,
A process cartridge that is detachable from the image forming apparatus.
The invention of claim 7
The electrophotographic photoreceptor according to any one of claims 1 to 5,
Charging means for charging the electrophotographic photoreceptor;
A latent image forming means for forming an electrostatic latent image on the surface of the charged electrophotographic photosensitive member;
Developing means for developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive member with toner to form a toner image;
Transfer means for transferring a toner image formed on the surface of the electrophotographic photosensitive member to a recording medium;
An image forming apparatus.
The invention of claim 8
Hollow metal oxide particles comprising hollow particles composed of a metal oxide and an acceptor compound attached to the surface of the hollow particles.
The invention of claim 9
Forming a metal oxide film on the surface of the resin particles;
Firing the resin particles having the metal oxide film formed thereon to remove the resin particles to produce hollow metal oxide particles; and
Attaching an acceptor compound to the surface of the hollow metal oxide particles;
The manufacturing method of the hollow metal oxide particle which has this.
The invention of claim 10
Forming a metal oxide film on the surface of the resin particles;
Firing the resin particles having the metal oxide film formed thereon to remove the resin particles to produce hollow metal oxide particles; and
Attaching an acceptor compound to the surface of the hollow metal oxide particles;
A step of forming a subbing layer by applying a coating liquid containing empty metal oxide particles and a binder resin to which the acceptor compound is adhered on a conductive support, and then drying and curing the coating film;
Providing a photosensitive layer on the undercoat layer;
A process for producing an electrophotographic photosensitive member having

According to the first aspect of the present invention, compared to the case where the undercoat layer does not contain the hollow metal oxide particles to which the acceptor compound is attached, the occurrence of unintended fine black spots in the image during repeated use is suppressed. An electrophotographic photoreceptor is provided.
According to the invention of claim 2, compared to the case where the metal oxide constituting the hollow metal oxide particles is not the specific metal oxide, the electrophotographic photosensitive member in which the generation of unintended fine black spots in the image is suppressed during repeated use. The body is provided.
According to the third, fourth, and fifth aspects of the present invention, there is provided an electrophotographic photosensitive member that suppresses the occurrence of unintended minute black spots in an image when repeatedly used compared to a case where the acceptor compound is not the anthraquinone compound or perylene compound. Provided.
According to the invention of claim 6, compared with the case where the undercoat layer of the electrophotographic photosensitive member does not contain the hollow metal oxide particles to which the acceptor compound is attached, the minute black spots that are not intended for the image during repeated use are formed. A process cartridge in which generation is suppressed is provided.
According to the seventh aspect of the present invention, compared to the case where the undercoat layer of the electrophotographic photosensitive member does not contain the hollow metal oxide particles to which the acceptor compound is attached, the minute black spots that are not intended for the image during repeated use are formed. An image forming apparatus in which occurrence is suppressed is provided.
According to the eighth aspect of the invention, compared to the case where the hollow metal oxide particles to which the acceptor compound is adhered are not included in the undercoat layer of the electrophotographic photosensitive member, the generation of unintended fine black spots in the image during repeated use. Inhibited hollow metal oxide particles are provided.
According to the ninth aspect of the invention, compared to the case where the hollow metal oxide particles to which the acceptor compound is attached are not included in the undercoat layer of the electrophotographic photosensitive member, generation of unintended fine black spots in the image during repeated use. A method for producing suppressed hollow metal oxide particles is provided.
According to the invention of claim 10, the electrophotography in which the occurrence of unintended fine black spots in the image during repeated use is suppressed as compared with the case where the hollow metal oxide particles having the acceptor compound attached thereto are not included in the undercoat layer. A method for producing a photoreceptor is provided.

1 is a schematic diagram illustrating an example of a configuration of an electrophotographic photosensitive member according to an exemplary embodiment. 1 is an overall configuration diagram illustrating an example of a configuration of an image forming apparatus according to an exemplary embodiment. It is a whole lineblock diagram showing other examples of composition of an image forming device concerning this embodiment.

Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings, but the present invention is not limited to the embodiments described below.
The electrophotographic photosensitive member according to the present embodiment is a hollow metal oxide in which an acceptor compound is attached to the surface of a hollow particle that is disposed on a conductive support and the conductive support and is composed of a metal oxide. An undercoat layer containing physical particles and a binder resin, and a photosensitive layer disposed on the undercoat layer.

<Electrophotographic photoreceptor>
FIG. 1 is a schematic view showing an example of the configuration of the electrophotographic photosensitive member of the present embodiment. An electrophotographic photoreceptor 101 shown in FIG. 1 includes a function-separated photosensitive layer 103 in which a charge generation layer 105 and a charge transport layer 106 are separately provided. An undercoat layer 104 is provided on a conductive support 102. The charge generation layer 105, the charge transport layer 106, and the protective layer 107 are stacked in this order. The undercoat layer 104 is a hollow particle in which an acceptor compound is attached to the surface of a hollow particle (appropriately referred to as “hollow metal oxide particle”) composed of a binder resin and a metal oxide (appropriately, “acceptor property”). (Referred to as “hollow metal oxide particles”).

  Since the electrophotographic photosensitive member 101 has the undercoat layer 104 having such a configuration, unintended minute black spots are prevented from being generated in an image during repeated use, and image density may be lowered during repeated use. It is suppressed. The reason is considered as follows.

When the undercoat layer contains metal oxide particles, the charge mobility differs greatly between the case where the charge moves inside the particle and the case where the charge moves outside the surface (surface). Remaining in the subbing layer is considered to be a cause of image quality abnormality. Therefore, the present inventor believes that if the undercoat layer is configured so that the charge moves preferentially outside the particle rather than the inside of the particle, the residual charge is suppressed, and as a result, the image quality abnormality is suppressed. It was.
For example, if the surface of the hollow resin particles is coated with a metal oxide, the undercoat layer includes a solid metal oxide particle that exhibits functions similar to those of the metal oxide particles and has no voids inside. When the undercoat layer is formed, the specific gravity is close to that of the binder resin, so that sedimentation hardly occurs, dispersibility is improved, and trapping of charges at the interface due to aggregation of metal oxides is suppressed, Charge accumulation during repeated use is suppressed.

  However, as a result of further studies by the inventor, it is considered that the resin particles inside the hindered charge transfer in the particles in which the resin particles are coated with the metal oxide as described above. Therefore, the present inventor made metal oxide particles (hollow metal oxide particles) having a hollow structure substantially free of resin inside the particles, and further attached an acceptor compound to the surface of the hollow metal oxide particles. It was found that the occurrence of image defects (such as black spots) can be more effectively suppressed by forming an undercoat layer using the particles (acceptor hollow metal oxide particles). With the acceptor hollow metal oxide particles as described above, the dispersibility is high, and hindering the charge transfer by the resin is suppressed, and the charge transfer from the upper layer (for example, charge generation layer) by the acceptor compound on the surface. Therefore, it is considered that generation of black spots due to charge accumulation is suppressed when image formation is repeatedly performed.

  Hereinafter, each element of the electrophotographic photosensitive member 101 having the configuration shown in FIG. 1 will be mainly described. However, the configuration of the electrophotographic photosensitive member according to the present embodiment is not limited to this. For example, an integrated photosensitive layer having functions of a charge generation layer and a charge transport layer may be provided. If necessary, an intermediate layer may be provided between the undercoat layer and the photosensitive layer. Further, it is not always necessary to provide a protective layer that becomes the outermost surface layer.

(Conductive support)
Any conductive support may be used as long as it is conventionally used. For example, metals such as aluminum, nickel, chromium, stainless steel, and plastic films provided with thin films such as aluminum, titanium, nickel, chromium, stainless steel, gold, vanadium, tin oxide, indium oxide, ITO, etc. Examples thereof include paper coated with or impregnated with a property-imparting agent, and a plastic film. The shape of the conductive support 102 is not limited to a drum shape, and may be a sheet shape or a plate shape.
In the case of using a metal pipe as the conductive support 102, the surface may remain as it is, or a process such as mirror cutting, etching, anodizing, rough cutting, centerless grinding, sand blasting, wet honing is performed in advance. It may be.

(Undercoat layer)
The undercoat layer 104 is provided for the purpose of preventing light reflection on the surface of the conductive support 102 and preventing unnecessary carriers from flowing from the conductive support 102 to the photosensitive layer 103. The undercoat layer 104 in the electrophotographic photosensitive member 101 of the present embodiment is configured in a state where hollow metal oxide particles to which an acceptor compound is attached are dispersed in a binder resin, and the acceptor hollow metal oxide particles and It is formed by applying a coating liquid containing a binder resin on the conductive support 102.

-Binder resin-
Examples of the binder resin contained in the undercoat layer 104 include acetal resins such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, and polyvinyl chloride resin. , Polyvinyl acetate resins, vinyl chloride-vinyl acetate-maleic anhydride resins, silicone resins, silicone-alkyd resins, phenolic resins, phenol-formaldehyde resins, melamine resins, urethane resins and other known polymer resin compounds, charge transporting groups A charge transporting resin having a conductive property such as polyaniline is used. Among these, resins that are insoluble in the upper coating solvent are preferably used, and phenol resins, phenol-formaldehyde resins, melamine resins, urethane resins, epoxy resins, and the like are particularly preferable.

-Hollow metal oxide particles with acceptor compound attached-
Next, the hollow metal oxide particles to which the acceptor compound is attached will be described. The hollow metal oxide particles to which the acceptor compound used in the present embodiment is attached are configured to have hollow particles made of a metal oxide and an acceptor compound attached to the surface of the hollow particles.

~ Hollow metal oxide particles ~
As the metal oxide constituting the hollow metal oxide particles, a powder resistance of about 10 ² Ω · cm to 10 ¹¹ Ω · cm is required. Among these, titanium oxide, zinc oxide, aluminum oxide, silicon oxide, tin oxide, and zirconium oxide having the above resistance values are desirable. If the resistance value of the metal oxide is not less than the lower limit of the above range, sufficient leakage resistance is obtained, and if it is not more than the upper limit, an increase in the residual potential is suppressed. Two or more different metal oxides may be mixed and used.

The particle diameter of the hollow metal oxide particles is desirably 0.02 μm or more and 1.0 μm or less from the viewpoint of dispersibility in the coating solution for forming the undercoat layer and formation of a conductive path in the undercoat layer. Particularly, those having a thickness of 0.05 μm or more and 0.3 μm or less are preferably used because they have high dispersibility in the coating solution for forming the undercoat layer and are excellent in forming a conductive path in the undercoat layer.
In the present embodiment, the particle diameter of resin particles, hollow metal oxide particles, and the like is a value measured by microscopic observation such as an optical microscope, a scanning electron microscope, or a transmission electron microscope.

~ Acceptor compound ~
By attaching the acceptor compound to the surface of the hollow metal oxide particles, the effect of attracting the charge of the upper layer is increased, and the performance of preventing the accumulation of residual charges during repeated use is improved.
Any acceptor compound may be used as long as it has a group that reacts with the hollow metal oxide particles and the effects of the present embodiment can be obtained. In particular, a compound having a hydroxyl group is preferably used. More desirably, an acceptor compound having an anthraquinone structure having a hydroxyl group is used. Examples of the compound having an anthraquinone structure having a hydroxyl group include a hydroxyanthraquinone compound and an aminohydroxyanthraquinone compound, both of which are desirably used. More specifically, alizarin, quinizarin, anthralfin, purpurin, and the like, and derivatives thereof are particularly preferably used.
As the anthraquinone compound, those having a structure represented by the following general formula (I) are desirable.

In formula (I), R ^{1 to} R ⁸ are each independently a hydrogen atom, halogen atom, hydroxyl group, amino group, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryl group Or a carboxyl group.

  Further, as the acceptor compound, a perylene compound is also desirably used. From the viewpoint of preventing residual potential accumulation, a perylene compound having a structure represented by the following general formula (II) is desirable, and a perylene compound having a structure represented by (2) or (3) is particularly desirable.

In formula (II), R ^{a to} R ^b are each independently a hydrogen atom, a halogen atom, a hydroxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a nitro group, a cyano group, an amino group, or A carboxyl group is shown.

In formula (2), R ⁹ and R ¹⁰ each independently represent a substituted or unsubstituted alkylene group.

In formula (3), R ¹¹ and R ¹² each independently represent an alkylene group, and R ¹³ and R ¹⁴ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted group. An alkoxy group, a nitro group, a cyano group, an amino group, or a carboxyl group is shown.

  The method for producing the acceptor hollow metal oxide particles is not particularly limited. For example, the step of forming a metal oxide film on the surface of the resin particles and the firing of the resin particles on which the metal oxide film is formed are performed. The method of removing the said resin particle by this and producing a hollow metal oxide particle, and the process of attaching an acceptor compound to the surface of the said hollow metal oxide particle are mentioned.

(1) Metal oxide film formation process First, a metal oxide film is formed on the surface of the resin particles.
As the resin particles, cross-linked resin particles are particularly preferably used. As the cross-linked resin particles, cross-linked polystyrene particles, cross-linked styrene-acrylic particles, cross-linked polymethyl methacrylate particles and the like are excellent in coating (immobilization) of metal oxides and are desirably used. These resin particles are produced by a known method. For example, the method of the Example mentioned later is mentioned.

  The particle diameter of the resin particles is preferably 0.02 μm or more and 1 μm or less, and particularly preferably 0.05 μm or more and 0.3 μm or less. If it is a resin particle having a particle size in the above range, the acceptor hollow metal oxide particles formed later using this resin particle have high dispersibility in the coating solution for forming the undercoat layer. Excellent in forming conductive paths.

  The formation of the metal oxide film on the surface of the resin particles is not particularly limited, and a known technique such as a gas phase method or a liquid phase method is applied, but a liquid phase precipitation method is particularly preferably used. Specifically, the liquid phase precipitation method is a method obtained by reacting a metal alkoxide with water, a method obtained by preparing a metal complex gel from a metal organic acid salt solution, and heating and firing the metal complex gel, a zinc compound and a base A method of obtaining zinc hydroxide from an aqueous solution and heating and baking zinc hydroxide.

(2) Firing step After forming a metal oxide film on the surface of the resin particles, firing is performed to remove the resin particles, thereby obtaining metal oxide particles having a hollow structure.
Firing depends on the material of the resin particles and the metal oxide film, but usually the resin particles with the metal oxide film formed on the surface are subjected to high heat at 300 ° C or higher and below the melting point of the metal oxide. Is done. Metal oxide particles having a hollow structure (hollow metal oxide particles) are obtained by firing. In addition, after firing, the hollow metal oxide particles may contain resin particle residues, but this does not hinder charge transfer and causes no problem.

(3) Acceptor compound attaching step An acceptor compound is attached to the surface of the hollow metal oxide particles obtained by firing.
The amount of the acceptor compound attached to the surface of the hollow metal oxide particles may be set according to each material of the hollow metal oxide particles and the acceptor compound so that the effect of the present embodiment can be obtained. . From the viewpoint of obtaining the effect of attracting charges by the acceptor compound without impairing the dispersibility of the particles, it is preferably 0.01% by mass to 30% by mass, more preferably 0.05% by mass with respect to the hollow metal oxide particles. It is used in the range of 20% by mass or less. If it is 0.01% by mass or more, sufficient acceptor properties that contribute to the suppression of charge accumulation in the undercoat layer are imparted, and it is suppressed from causing deterioration in sustainability such as an increase in residual potential during repeated use. The Moreover, since aggregation of the hollow metal oxide particles hardly occurs when the content is 30% by mass or less, the hollow metal oxide particles form a good conductive path in the undercoat layer at the time of forming the undercoat layer. It is suppressed that the sustainability is lowered such as an increase in residual potential, and image quality defects such as black spots are hardly caused.

The acceptor compound is preferably attached to the entire surface of the hollow metal oxide particles, but may be attached to a part of the surface.
The particle diameter of the hollow metal oxide particles to which the acceptor compound is attached is 0.02 μm or more and 1.0 μm or less from the viewpoint of dispersibility in the coating solution for forming the undercoat layer and formation of a conductive path in the undercoat layer. Desirably, 0.05 μm or more and 0.5 μm or less is more desirable.

In the present embodiment, the coating liquid containing the hollow metal oxide particles to which the acceptor compound is attached and the binder resin is applied on the conductive support, and then the coating film is dried and cured. An undercoat layer is formed.
The hollow metal oxide particles to which the acceptor compound is attached may be used as a mixture of two or more kinds, such as those having different particle sizes, different metal oxide materials, and different acceptor compound materials.
Further, the acceptor hollow metal oxide particles may be surface-treated with a coupling agent to control the powder resistance.

  The ratio of the acceptor hollow metal oxide particles and the binder resin in the undercoat layer is not particularly limited, and is set within a range in which desired electrophotographic photoreceptor characteristics can be obtained. From the viewpoint of forming a conductive path, the acceptor hollow metal oxide particles are desirably contained in the undercoat layer in a ratio of 10% by volume to 80% by volume, and a ratio of 20% by volume to 70% by volume. It is further desirable to be included.

  In forming the undercoat layer 104, a coating solution in which at least a binder resin and acceptor hollow metal oxide particles are added to a solvent is used. Examples of such solvents include aromatic hydrocarbon solvents such as toluene and chlorobenzene, aliphatic alcohol solvents such as methanol, ethanol, n-propanol, iso-propanol, and n-butanol, acetone, cyclohexanone, and 2-butanone. Ketone solvents, halogenated aliphatic hydrocarbon solvents such as methylene chloride, chloroform, ethylene chloride, cyclic or linear ether solvents such as tetrahydrofuran, dioxane, ethylene glycol, diethyl ether, methyl acetate, ethyl acetate, n acetate -Organic solvents, such as ester solvents, such as butyl. These solvents are used alone or in combination of two or more. When mixing, any solvent may be used as long as it is a solvent that dissolves the binder resin as a mixed solvent.

  Examples of the method for dispersing the acceptor hollow metal oxide particles in the coating solution for forming the undercoat layer include, for example, a media disperser such as a ball mill, a vibrating ball mill, an attritor, a sand mill, a horizontal sand mill, a stirrer, an ultrasonic wave Medialess dispersers such as dispersers, roll mills, and high-pressure homogenizers are used. Further, examples of the high-pressure homogenizer include a collision method in which the dispersion liquid is dispersed by liquid-liquid collision or liquid-wall collision in a high pressure state, and a penetration method in which the fine liquid is penetrated and dispersed in a high pressure state.

As a method of applying the coating solution for forming the undercoat layer thus obtained on the support 102, a dip coating method, a push-up coating method, a wire bar coating method, a spray coating method, a blade coating method, a knife coating method, Examples include a curtain coating method.
The thickness of the undercoat layer 104 is preferably 15 μm or more and more preferably 20 μm or more and 50 μm or less from the viewpoint of leakage resistance and prevention of residual potential accumulation.
Further, resin particles may be added to the undercoat layer in order to adjust the surface roughness. As the resin particles, for example, silicone resin particles, cross-linked polymethyl methacrylate resin particles, and the like are used.
Further, the surface of the undercoat layer may be polished for adjusting the surface roughness. As a polishing method, for example, buffing, sandblasting, wet honing, grinding, or the like is used.

(Middle layer)
Although not shown, an intermediate layer may be further provided on the undercoat layer in order to improve electrical characteristics, improve image quality, improve image quality maintenance, and improve adhesiveness of the photosensitive layer. As the binder resin used for the intermediate layer, acetal resins such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl In addition to polymer resin compounds such as acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, melamine resin, zirconium, titanium, aluminum, manganese, silicon, etc. Contains organometallic compounds. These compounds are used alone or as a mixture or polycondensate of a plurality of compounds. Among these, organometallic compounds containing zirconium or silicon are excellent in performance, such as low residual potential, little potential change due to environment, and little potential change due to repeated use.

As the solvent used for forming the intermediate layer, known organic solvents, for example, aromatic hydrocarbon solvents such as toluene and chlorobenzene, aliphatics such as methanol, ethanol, n-propanol, iso-propanol, and n-butanol Alcohol solvents, ketone solvents such as acetone, cyclohexanone and 2-butanone, halogenated aliphatic hydrocarbon solvents such as methylene chloride, chloroform and ethylene chloride, cyclic or linear such as tetrahydrofuran, dioxane, ethylene glycol and diethyl ether Examples include ether solvents, ester solvents such as methyl acetate, ethyl acetate, and n-butyl acetate. These solvents are used alone or in combination of two or more. When mixing, any solvent may be used as long as it dissolves the binder resin as a mixed solvent.
As the coating method for forming the intermediate layer, for example, usual methods such as dip coating, push-up coating, wire bar coating, spray coating, blade coating, knife coating, and curtain coating are used.
In addition to improving the coatability of the upper layer, the intermediate layer also serves as an electrical blocking layer. However, if the thickness is too large, the electrical barrier becomes too strong, causing desensitization and potential increase due to repetition. . Therefore, when the intermediate layer is formed, the thickness is set in the range of 0.1 μm to 3 μm.

(Charge generation layer)
The charge generation layer 105 is formed by dispersing a charge generation material in an appropriate binder resin.
Examples of such charge generating materials include phthalocyanine pigments such as metal-free phthalocyanine, chlorogallium phthalocyanine, hydroxygallium phthalocyanine, dichlorotin phthalocyanine, and titanyl phthalocyanine. ), A chlorogallium phthalocyanine crystal having strong diffraction peaks at 7.4 °, 16.6 °, 25.5 ° and 28.3 ° at a Bragg angle (2θ ± 0.2 °) with respect to CuKα characteristic X-rays. Metal-free phthalocyanine crystals having strong diffraction peaks at 7.7 °, 9.3 °, 16.9 °, 17.5 °, 22.4 ° and 28.8 °, Bragg angle (2θ for CuKα characteristic X-ray) ± 0.2 °) at least 7.5 °, 9.9 °, 12.5 °, 16.3 °, 1 Hydroxygallium phthalocyanine crystal having strong diffraction peaks at .6 °, 25.1 ° and 28.3 °, Bragg angle (2θ ± 0.2 °) to CuKα characteristic X-ray of at least 9.6 °, 24.1 ° And titanyl phthalocyanine crystals having a strong diffraction peak at 27.2 °.
In addition, as the charge generation material, for example, a quinone pigment, a perylene pigment, an indigo pigment, a bisbenzimidazole pigment, an anthrone pigment, a quinacridone pigment, and the like are used. These charge generation materials are used alone or in combination of two or more.

  Examples of the binder resin in the charge generation layer 105 include polycarbonate resin such as bisphenol A type or bisphenol Z type, acrylic resin, methacrylic resin, polyarylate resin, polyester resin, polyvinyl chloride resin, polystyrene resin, and acrylonitrile-styrene. Polymer resin, acrylonitrile-butadiene copolymer, polyvinyl acetate resin, polyvinyl formal resin, polysulfone resin, styrene-butadiene copolymer resin, vinylidene chloride-acrylonitrile copolymer resin, vinyl chloride-vinyl acetate resin, vinyl chloride- Use vinyl acetate-maleic anhydride resin, silicone resin, phenol-formaldehyde resin, polyacrylamide resin, polyamide resin, poly-N-vinylcarbazole resin, etc.These binder resins are used alone or in combination of two or more. The mixing ratio of the charge generating material and the binder resin is desirably in the range of 10: 1 to 1:10.

  In forming the charge generation layer 105, a coating solution in which the above components are added to a solvent is used. Examples of such solvents include aromatic hydrocarbon solvents such as toluene and chlorobenzene, aliphatic alcohol solvents such as methanol, ethanol, n-propanol, iso-propanol, and n-butanol, acetone, cyclohexanone, and 2-butanone. Ketone solvents, halogenated aliphatic hydrocarbon solvents such as methylene chloride, chloroform, ethylene chloride, cyclic or linear ether solvents such as tetrahydrofuran, dioxane, ethylene glycol, diethyl ether, methyl acetate, ethyl acetate, n acetate -Organic solvents, such as ester solvents, such as butyl. These solvents are used alone or in combination of two or more. When mixing, any solvent may be used as long as it is a solvent that dissolves the binder resin as a mixed solvent.

In order to disperse the charge generation material in the resin, the coating liquid is subjected to a dispersion treatment. As a dispersion method, a media disperser such as a ball mill, a vibrating ball mill, an attritor, a sand mill, or a horizontal sand mill, or a medialess disperser such as a stirrer, an ultrasonic disperser, a roll mill, or a high-pressure homogenizer is used. Further, examples of the high-pressure homogenizer include a collision method in which the dispersion liquid is dispersed by liquid-liquid collision or liquid-wall collision in a high pressure state, and a penetration method in which the fine liquid is penetrated and dispersed in a high pressure state.
Examples of methods for applying the coating solution thus obtained onto the undercoat layer 104 include dip coating, push-up coating, wire bar coating, spray coating, blade coating, knife coating, curtain coating, and the like. Is mentioned.
The thickness of the charge generation layer 105 is desirably set in a range from 0.01 μm to 5 μm, and more desirably from 0.05 μm to 2.0 μm.

(Charge transport layer)
As the charge transport layer 106, a layer formed by a known technique is used. The charge transport layer 106 is formed containing a charge transport material and a binder resin, or is formed containing a polymer charge transport material.
Any known material may be used as the charge transport material contained in the charge transport layer 106, but the following are exemplified. Oxadiazole derivatives such as 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole, 1,3,5-triphenyl-pyrazoline, 1- [pyridyl- (2)]-3 Pyrazoline derivatives such as-(p-diethylaminostyryl) -5- (p-diethylaminostyryl) pyrazoline, triphenylamine, tri (P-methyl) phenylamine, N, N'-bis (3,4-dimethylphenyl) biphenyl Aromatic tertiary amino compounds such as -4-amine, dibenzylaniline, 9,9-dimethyl-N, N′-di (p-tolyl) fluoren-2-amine, N, N′-diphenyl-N, Aromatic tertiary diamino compounds such as N′-bis (3-methylphenyl)-[1,1-biphenyl] -4,4′-diamine, 3- (4′dimethylaminophenyl)- 1,2,4-triazine derivatives such as 1,6-di- (4′-methoxyphenyl) -1,2,4-triazine, 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone, 4-diphenylaminobenzaldehyde-1 , 1-diphenylhydrazone, hydrazone derivatives such as [p- (diethylamino) phenyl] (1-naphthyl) phenylhydrazone, quinazoline derivatives such as 2-phenyl-4-styryl-quinazoline, 6-hydroxy-2,3-di ( benzofuran derivatives such as p-methoxyphenyl) -benzofuran, α-stilbene derivatives such as p- (2,2-diphenylvinyl) -N, N′-diphenylaniline, enamine derivatives, carbazole derivatives such as N-ethylcarbazole, poly Holes such as -N-vinylcarbazole and its derivatives Feed material. Quinone compounds such as chloranil, bromoanil, anthraquinone, tetracyanoquinodimethane compounds, fluorenone compounds such as 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2- ( 4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, 2,5-bis (4-naphthyl) -1,3,4-oxadiazole, 2,5 -Oxadiazole compounds such as bis (4-diethylaminophenyl) 1,3,4 oxadiazole, xanthone compounds, thiophene compounds, 3,3 ′, 5,5 ′ tetra-t-butyldiphenoquinone, etc. Examples thereof include an electron transport material such as a diphenoquinone compound, or a polymer having a group consisting of the above-described compounds in the main chain or side chain. These charge transport materials are used alone or in combination of two or more.
Especially, the thing of the structure shown by the following formula | equation (B-1) thru | or (B-3) from a viewpoint of mobility is desirable.

In Structural Formula (B-1), R ^B1 represents a hydrogen atom or a methyl group, and n ′ represents 1 or 2. Ar ^B1 and Ar ^B2 each independently represent a substituted or unsubstituted aryl group, and the substituent includes a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or A substituted amino group substituted with an alkyl group having 1 to 3 carbon atoms.

In the structural formula (B-2), R ^B2 and R ^{B2 ′} each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. R ^B3 , R ^{B3 ′} , R ^B4 , and R ^{B4 ′} each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an alkyl group having 1 to 2 carbon atoms. Represents an amino group substituted with or a substituted or unsubstituted aryl group, or —C (R ^B5 ) ═C (R ^B6 ) (R ^B7 ), and R ^B5 , R ^B6 and R ^B7 are a hydrogen atom, substituted or An unsubstituted alkyl group or a substituted or unsubstituted aryl group is represented. M ′ and n ″ are integers from 0 to 2.

In Structural Formula (B-3), R ^B8 represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a substituted or unsubstituted aryl group, or —CH═CH—CH═ C (Ar ^B3 ) ₂ is represented. Ar ^B3 represents a substituted or unsubstituted aryl group. R ^B9 and R ^B10 are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an amino group substituted with an alkyl group having 1 to 2 carbon atoms, or a substituted group. Or an unsubstituted aryl group is represented.

  Any binder resin may be used for the charge transport layer 106 as long as it is a known one, but a resin on which an electrically insulating film is formed is desirable. For example, polycarbonate resin, polyester resin, polyarylate resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, acrylonitrile-styrene copolymer, acrylonitrile-butadiene copolymer, polyvinyl acetate resin, styrene -Butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin. Silicon-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N-carbazole, polyvinyl butyral, polyvinyl formal, polysulfone, casein, gelatin, polyvinyl alcohol, ethyl cellulose, phenol resin, polyamide, polyacrylamide, carboxymethyl cellulose, Insulating resins such as vinylidene chloride polymer wax and polyurethane, and polyvinyl carbazole, polyvinyl anthracene, polyvinyl pyrene, polysilane, polyester polymer charges disclosed in JP-A-8-176293 and JP-A-8-208820 Examples include organic photoconductive polymers such as transport materials, but are not limited thereto. These binder resins are used singly or in combination of two or more. In particular, polycarbonate resins, polyester resins, methacrylic resins, and acrylic resins are compatible with charge transport materials, soluble in solvents, and strong. Excellent and desirable to use.

The blending ratio (mass ratio) of the binder resin and the charge transport material is arbitrarily set in any case, but it is necessary to consider reduction in electrical characteristics and film strength.
An organic photoconductive polymer may be used alone. As the organic photoconductive polymer, known ones having charge transporting properties such as poly-N-vinylcarbazole and polysilane are used. In particular, polyester polymer charge transport materials disclosed in JP-A-8-176293 and JP-A-8-208820 have a high charge transport property and are particularly desirable. The polymer charge transporting material alone is used as a charge transporting layer, but may be mixed with the binder resin to form a film.

  In addition, when the charge transport layer 106 is the outermost surface layer of the electrophotographic photosensitive member 101, lubricity is imparted so that the outermost surface layer is less likely to be worn or scratched. In order to make it easier to remove the developer attached to the surface of the toner, lubricating particles (for example, silica particles, fluorine resin particles such as alumina particles and polytetrafluoroethylene (PTFE), silicone resin particles) are included as particles. Let These lubricating particles may be used in combination of two or more.

In particular, fluorine resin particles are desirably used. Fluorine-based resin particles include tetrafluoroethylene resin, trifluorinated ethylene resin, hexafluoropropylene resin, vinyl fluoride resin, vinylidene fluoride resin, difluorodiethylene chloride resin and copolymers thereof. It is desirable to select one or two or more types from among them, and tetrafluoroethylene resin and vinylidene fluoride resin are particularly desirable.
The primary particle size of the fluororesin is preferably 0.05 μm or more and 1 μm or less, more preferably 0.1 μm or more and 0.5 μm or less. When the primary particle size is less than 0.05 μm, aggregation during dispersion tends to proceed. On the other hand, if it exceeds 1 μm, image quality defects are likely to occur.
The content of the fluoric resin in the charge transport layer 106 in the charge transport layer 106 containing the fluoric resin is suitably 0.1% by mass or more and 40% by mass or less, particularly 1% by mass with respect to the total amount of the charge transport layer. % To 30% by mass is desirable. If the content is less than 1% by mass, the modification effect due to the dispersion of the fluororesin particles is not sufficient. On the other hand, if the content exceeds 40% by mass, the light transmission is lowered and the residual potential is increased by repeated use. come.

The charge transport layer 106 may be formed by applying and drying a charge transport layer forming coating solution in which a charge transport substance, a binder resin, and other materials are dissolved in a suitable solvent.
Examples of the solvent used for forming the charge transport layer 106 include aromatic hydrocarbon solvents such as toluene and chlorobenzene, aliphatic alcohol solvents such as methanol, ethanol, and n-butanol, acetone, cyclohexanone, and 2-butanone. Such as ketone solvents, halogenated aliphatic hydrocarbon solvents such as methylene chloride, chloroform and ethylene chloride, cyclic or linear ether solvents such as tetrahydrofuran, dioxane, ethylene glycol and diethyl ether, or mixed solvents thereof. Used. The mixing ratio of the charge transport material and the binder resin is preferably 10: 1 to 1: 5.
A small amount of silicone oil may be added to the coating solution for forming the charge transport layer as a leveling agent for improving the smoothness of the coating film.
Examples of the method for dispersing the lubricating particles in the charge transport layer 106 include a roll mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a high-pressure homogenizer, an ultrasonic disperser, a colloid mill, a collision-type medialess disperser, and a through-type medialess. A method such as a disperser is used.

Examples of the dispersion of the coating liquid for forming the charge transport layer 106 include a method in which lubricating particles are dispersed in a solution such as a binder resin or a charge transport material dissolved in a solvent.
As a method of controlling the temperature of the coating liquid in the coating liquid manufacturing process from 0 ° C. to 50 ° C., cool with water, cool with wind, cool with refrigerant, adjust the room temperature of the manufacturing process, warm with hot water, hot air Use heating, heating with a heater, making a coating liquid manufacturing facility with a material that does not easily generate heat, creating a coating liquid manufacturing facility with a material that easily dissipates heat, or creating a coating liquid manufacturing facility with a material that easily stores heat Is done.

As a method for mixing the coating liquid, methods such as a stirrer, stirring with a stirring blade, a roll mill, a sand mill, an attritor, a ball mill, a high-pressure homogenizer, and an ultrasonic disperser are used. As a dispersion method, a sand mill, an attritor, a ball mill, a high-pressure homogenizer, an ultrasonic disperser, a roll mill, or the like is used.
It is also effective to add a small amount of a dispersion aid in order to improve the dispersion stability of the dispersion and to prevent aggregation during the formation of the coating film. Examples of the dispersion aid include surfactants, fluorine-based polymers, silicone-based polymers, and silicone oils.

Examples of the coating method used when the charge transport layer 106 is provided include a dip coating method, a push-up coating method, a spray coating method, a roll coater coating method, a wire bar coating method, a gravure coating method, a bead coating method, a curtain coating method, A blade coating method, an air knife coating method, or the like is used.
The thickness of the charge transport layer 106 is desirably 5 μm or more and 50 μm or less, and more desirably 10 μm or more and 40 μm or less.

Further, the electrophotographic photosensitive member 101 of this embodiment is oxidized in the photosensitive layer 103 for the purpose of preventing deterioration of the electrophotographic photosensitive member 101 due to ozone, oxidizing gas, or light / heat generated in the electrophotographic apparatus. Additives such as an inhibitor and a light stabilizer may be added.
Examples of the antioxidant include hindered phenol, hindered amine, paraphenylenediamine, arylalkane, hydroquinone, spirochroman, spiroidanone and their derivatives, organic sulfur compounds, and organic phosphorus compounds.
Specific examples of antioxidants include phenolic antioxidants such as 2,6-di-t-butyl-4-methylphenol, styrenated phenol, n-octadecyl-3- (3 ′, 5′-di -T-butyl 4'-hydroxyphenyl) -propionate, 2,2'-methylene-bis- (4-methyl-6-t-butylphenol), 2-t-butyl-6- (3'-t-butyl) -5'-methyl-2'-hydroxybenzyl) -4-methylphenyl acrylate, 4,4'-butylidene-bis- (3-methyl-6-tert-butyl-phenol), 4,4'-thio-bis -(3-methyl 6-tert-butylphenol), 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, tetrakis- [methylene-3- (3 ', 5'Di-t-butyl-4'-hydroxy-phenyl) propionate] -methane, 3,9-bis [2- [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1 , 1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane and the like.

  Among hindered amine compounds, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1- [2- [3 -(3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] -2, 2,6,6-tetramethylpiperidine, 8-benzyl-7,7,9,9-tetramethyl-3-octyl-1,3,8-triazaspiro [4,5] undecane-2,4-dione, 4, -Benzoyloxy-2,2,6,6-tetramethylpiperidine, dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine heavy succinate Compound, poly [{6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diimyl} {(2,2,6,6-tetramethyl- 4-piperidyl) imino} hexamethylene {(2,3,6,6, -tetramethyl-4-piperidyl) imino}], 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2 N-Butylmalonate bis (1,2,2,6,6-pentamethyl-4-piperidyl), N, N′-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl-N -(1,2,2,6,6-pentamethyl-4piperidyl) amino] -6-chloro-1,3,5-triazine condensate and the like.

Dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, pentaerythritol-tetrakis- ( β-lauryl-thiopropionate), ditridecyl-3,3′-thiodipropionate, 2-mercaptobenzimidazole and the like.
Examples of the organophosphorus antioxidant include trisnonylphenyl phosfte, triphenyl phosfeft, tris (2,4-di-t-butylphenyl) -phosfte and the like.
Organic sulfur-based and organic phosphorus-based antioxidants are referred to as secondary antioxidants, and a synergistic effect can be obtained by using them together with primary antioxidants such as phenols or amines.

Examples of the light stabilizer include benzophenone, benzotriazole, dithiocarbamate, and tetramethylpiperidine derivatives.
Examples of the benzophenone light stabilizer include 2-hydroxy-4-methoxy benzophenone, 2-hydroxy-4-octoxy benzophenone, and 2,2′-di-hydroxy-4-methoxy benzophenone. As a benzotriazole-based light stabilizer, 2- (2′-hydroxy-5′methylphenyl-)-benzotriazole, 2- [2′-hydroxy-3 ′-(3 ″, 4 ″, 5 ″, 6 ″ -tetra-hydrophthalimido-methyl) -5′-methylphenyl] -benzotriazole, 2- (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3 ′, 5′-t-butylphenyl) -benzotriazole, 2- (2′-hydroxy-5′-t-octylphenyl) -benzotriazole, 2- (2′-hydroxy 3 ', 5'-di-t-amylphenyl) -benzotriazole and the like.

Other compounds include 2,4-di-t-butylphenyl-3 ′, 5′-di-t-butyl-4′-hydroxybenzoate, nickel dibutyl-dithiocarbamate, and the like.
Further, at least one kind of electron-accepting substance is contained for the purpose of improving sensitivity, reducing residual potential, and reducing fatigue during repeated use.
Examples of the electron acceptor include succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrabromophthalic anhydride, tetracyanoethylene, tetracyanoquinodimethane, o-dinitrobenzene, m-dinitrobenzene, Examples include chloranil, dinitroanthraquinone, trinitrofluorenone, picric acid, o-nitrobenzoic acid, p-nitrobenzoic acid, and phthalic acid. Of these, fluorenone-based, quinone-based, and benzene derivatives having electron-withdrawing substituents such as Cl, CN, NO ₂ are particularly preferable.

(Protective layer)
In the electrophotographic photosensitive member 101 having a laminated structure, the protective layer 107 is used as necessary to prevent chemical change of the charge transport layer 106 during charging or to further improve the mechanical strength of the photosensitive layer 103. .
The protective layer 107 includes a binder resin (including a curable resin) and a charge transporting compound. Furthermore, lubricating particles (fillers) may be included. Examples of the form of the protective layer 107 include a cured resin film containing a curable resin and a charge transporting compound, and a film formed by containing a charge transporting material in an appropriate binder resin. Known resins are used as the curable resin, and examples thereof include phenol resins, acrylic resins, polyurethane resins, melamine resins, diallyl phthalate resins, and siloxane resins.

By containing the lubricating particles in the protective layer 107 serving as the outermost surface layer, the wear rate of the outermost surface layer is reduced by reducing the surface energy, and the life of the electrophotographic photosensitive member 101 is extended. Examples of the lubricating particles include silica resin particles, alumina resin particles, fluorine resin particles such as polytetrafluoroethylene (PTFE), and silicone resin particles. Two or more kinds of lubricating particles may be mixed and used. In particular, fluorine resin particles are desirably used.
Fluorine-based resin particles include tetrafluoroethylene resin, trifluorinated ethylene resin, hexafluoropropylene resin, vinyl fluoride resin, vinylidene fluoride resin, difluorodiethylene chloride resin and copolymers thereof. It is desirable to select one or two or more types from among them, and tetrafluoroethylene resin and vinylidene fluoride resin are particularly desirable.

The primary particle size of the lubricating particles is preferably 0.05 μm or more and 1 μm or less, and more preferably 0.1 μm or more and 0.5 μm or less. If the primary particle size is 0.05 μm or more, aggregation during dispersion is difficult to proceed, and if it is 1 μm or less, image quality defects are less likely to occur.
The content of the lubricating particles in the protective layer 107 is suitably 0.1% by mass or more and 60% by mass or less, and particularly preferably 1% by mass or more and 30% by mass or less with respect to the total amount of the protective layer. When the content is 1% by mass or more, the effect of reducing the surface energy by the lubricating particles is obtained. On the other hand, when the content is 60% by mass or less, the decrease in light transmission property is suppressed and the residual potential is increased by repeated use. Is suppressed.

The protective layer 107 is formed by applying a coating liquid for forming a protective layer in which a charge transport material, a binder resin, and other materials are dissolved in an appropriate solvent, and dispersing lubricating particles, and then drying. .
The solvent used for forming the protective layer 107 is preferably a solvent that does not erode the lower layer when forming the protective layer, and is an aliphatic alcohol solvent such as methanol, ethanol, n-butanol, acetone, cyclohexanone, 2-butanone. Such ketone solvents, cyclic or linear ether solvents such as ethylene glycol and diethyl ether, or mixed solvents thereof are used.

Silicone oil, fluorine oil, or the like may be added to the coating solution for forming the protective layer as a leveling agent for improving the smoothness of the coating film.
In addition, an anti-repellent agent or an adhesion enhancer may be added in order to prevent film formation and peeling of the protective layer. As the repellency inhibitor, a known material such as a surfactant having desired characteristics can be used. As the adhesion enhancer, a known material such as a surfactant or a coupling agent capable of obtaining desired characteristics is used.

As a method of dispersing the lubricating particles in the protective layer 107, a method similar to the method of dispersing the lubricating particles in the charge transport layer 106 is used.
It is also effective to add a small amount of a dispersion aid in order to improve the dispersion stability of the lubricating particles and to prevent aggregation during the formation of the coating film. Examples of the dispersion aid include surfactants, fluorine-based polymers, silicone-based polymers, and silicone oils.
In the formation of the protective layer 107, coating methods include blade coating method, wire bar coating method, spray coating method, dip coating method, bead coating method, air knife coating method, curtain coating method, ring coating method, and ink jet coating method. Ordinary methods such as are used.
The thickness of the protective layer 107 is desirably 0.5 μm or more and 20 μm or less, particularly 2 μm or more and 10 μm or less.

<Image forming apparatus and process cartridge>
Next, the image forming apparatus and the process cartridge according to the present embodiment will be described.
FIG. 2 is an overall configuration diagram illustrating a first example of the image forming apparatus according to the present embodiment. The image forming apparatus 1000 is a monochrome single-sided output printer that employs an electrophotographic system. The image forming apparatus 1000 receives the supply of electric power from the electrophotographic photosensitive member 61 rotating in the direction of arrow B in the figure and the power supply 65a, and rotates while contacting the electrophotographic photosensitive member 61, thereby the surface of the electrophotographic photosensitive member 61 is rotated. And a charging member 65 as charging means for charging. Here, the electrophotographic photosensitive member 61 corresponds to an example of the electrophotographic photosensitive member according to the above-described embodiment.

  Further, the image forming apparatus 1000 emits a laser beam toward the electrophotographic photosensitive member 61 to form an electrostatic latent image having a higher potential than the surroundings on the surface of the electrophotographic photosensitive member 61. The electrostatic latent image is formed by adhering monochrome (black) toner to the electrostatic latent image formed on the surface of the electrophotographic photosensitive member 61 using the exposure unit 7 as a forming unit and an electrostatic latent image developer containing black toner. Formed on the surface of the electrophotographic photosensitive member 61 by pressing a sheet conveyed to the electrophotographic photosensitive member 61 on which the toner image is formed and a developing device 64 that is a developing unit that forms a toner image by developing the image. A transfer roll 50 that is a transfer means for transferring the toner image that has been transferred onto the paper, and a fixing means that fixes the transferred image onto the paper by applying heat and pressure to the toner image transferred onto the paper. Equipped with vessel 10 There. Further, a cleaning device 62 that is a cleaning unit that contacts the electrophotographic photoreceptor 61 and removes residual toner remaining on the surface of the electrophotographic photoreceptor 61 after the toner image is transferred, and the electrophotographic photoreceptor after the toner image is transferred. A static elimination lamp 7 a for removing the electric charge remaining in 61 is also provided.

In the image forming apparatus 1000, both the charging member 65 and the electrophotographic photosensitive member 61 are in a roll shape extending in a direction perpendicular to FIG. 2, and both ends of these rolls are on the support member 100a. The roll is supported in a rotatable manner. The cleaning member 62 and the developing device 64 are also connected to the supporting member 100a. Thus, the charging member 65, the electrophotographic photosensitive member 61, the cleaning device 62, and the developing device 64 are connected to the supporting member 100a. By being integrated, the process cartridge 100 is configured.
By incorporating the process cartridge 100 into the image forming apparatus 1000, the image forming apparatus 1000 is provided with each part that is a component of these process cartridges. This process cartridge 100 corresponds to an example of the process cartridge of the present embodiment.

  The process cartridge 100 according to the present embodiment is not particularly limited as long as the process cartridge 100 includes the electrophotographic photosensitive member according to the present embodiment and is detachable from the image forming apparatus. For example, charging means for charging the electrophotographic photosensitive member, electrostatic latent image forming means for forming an electrostatic latent image on the charged electrophotographic photosensitive member, and electrostatic latent image formed on the electrophotographic photosensitive member are electrostatically charged. Developing means for developing a toner image with a latent image developer, transfer means for transferring a toner image formed on the electrophotographic photosensitive member to a transfer target, and residual toner on the electrophotographic photosensitive member after transfer is removed. You may integrally have at least 1 type selected from the group which consists of a cleaning means.

Hereinafter, an image forming operation in the image forming apparatus 1000 will be described.
The image forming apparatus 1000 includes a toner cartridge (not shown) in which black toner is stored, and the toner is supplied to the developing device 64 by the toner cartridge. The sheet on which the toner image is transferred is stored in the sheet feeding unit 1 and is conveyed from the sheet feeding unit 1 when an image formation is instructed by the user. After being performed, it is conveyed toward the left in the figure. In FIG. 2, the sheet conveyance path at this time is shown as a path indicated by a left-pointing arrow, and the sheet passes through this sheet conveyance path and the fixing image transferred onto the sheet is fixed by the fixing device 10. After being done, it is discharged to the left.

(Charging means)
When the charging member 65 charges the electrophotographic photoreceptor 61, a voltage is applied to the charging member 65. As for the voltage range, the DC voltage is preferably positive or negative 50 V or more and 2000 V or less, more preferably 100 V or more and 1500 V or less, depending on the required charging potential of the electrophotographic photosensitive member. In the case of superimposing the AC voltage, the peak-to-peak voltage is set to 400 V to 1800 V, preferably 800 V to 1600 V, and more preferably 1200 V to 1600 V. The frequency of the AC voltage is 50 Hz to 20,000 Hz, preferably 100 Hz to 5,000 Hz.

As the charging member 65, a member provided with an elastic layer, a resistance layer, a protective layer, or the like on the outer peripheral surface of the core material is desirably used. The charging member 65 rotates at the same peripheral speed as the electrophotographic photosensitive member 61 by contacting the electrophotographic photosensitive member 61 without any driving means, and functions as a charging means. It may be attached and rotated at a peripheral speed different from that of the electrophotographic photosensitive member 61 to be charged.
As the exposure unit 7, an optical system device that exposes a light source such as a semiconductor laser, an LED (light emitting diode), a liquid crystal shutter, or the like on the surface of the electrophotographic photosensitive member in a desired image manner may be used.

(Development means)
As the developing device 64, a known developing device using a normal or reversal developer such as a one-component system or a two-component system may be used. The shape of the toner used for the developing device 64 is not particularly limited, and may be indefinite, spherical, or other specific shape.

(Transfer means)
As a transfer means, in addition to a contact charging member such as a transfer roll 50, a contact transfer charger using a belt, a film, a rubber blade, or the like, a scorotron transfer charger using a corona discharge, a corotron transfer charger, etc. Can be mentioned.

(Cleaning means)
The cleaning device 62 is for removing residual toner adhering to the surface of the electrophotographic photosensitive member 61 after the transfer process. The cleaned electrophotographic photosensitive member 61 is repeatedly used for the image forming process described above. Is done. As the cleaning device, in addition to a cleaning blade, brush cleaning, roll cleaning, or the like may be used. Among these, it is desirable to use a cleaning blade. Examples of the material for the cleaning blade include urethane rubber, neoprene rubber, and silicone rubber.

If the surface layer of the electrophotographic photosensitive member according to the present embodiment contains fluorine-containing resin particles, the surface energy is low, so even if a cleaning blade is used as the cleaning device 62, the surface layer is hardly worn and long. A stable image is formed over a period of time.
Since the image forming apparatus according to the present embodiment includes the static elimination lamp 7a, the phenomenon that the residual potential of the electrophotographic photosensitive member 61 is brought into the next cycle when the electrophotographic photosensitive member 61 is repeatedly used is prevented. Therefore, the image quality can be further improved. Note that the image forming apparatus according to the present embodiment only needs to include the static elimination lamp 7a as necessary.

FIG. 3 is an overall configuration diagram illustrating a second example of the image forming apparatus according to the present embodiment.
The image forming apparatus 1000 ′ is a color printer. The image forming apparatus 1000 ′ includes electrophotographic photoreceptors 61K, 61C, 61M, and 61Y that rotate in the directions of arrows Bk, Bc, Bm, and By in the drawing, respectively. Here, the electrophotographic photoreceptors 61K, 61C, 61M, and 61Y correspond to an example of the electrophotographic photoreceptor according to the present embodiment.

  Further, charging members that charge the surfaces of the electrophotographic photosensitive members 61K, 61C, 61M, and 61Y around the electrophotographic photosensitive members 61K, 61C, 61M, and 61Y by rotating while being in contact with the respective electrophotographic photosensitive members. Each color of black (K), cyan (C), magenta (M), and yellow (Y) is irradiated onto the charged electrophotographic photosensitive members 61K, 61C, 61M, and 61Y by laser light on 65K, 65C, 65M, and 65Y. The electrostatic latent images on the exposure units 7K, 7C, 7M, and 7Y that form the electrostatic latent images of the electrophotographic photosensitive members are developed with an electrostatic latent image developer containing toner of each color, and each color toner image is developed. Developing units 64K, 64C, 64M, and 64Y are provided.

  In the image forming apparatus 1000 ′, among the above-described constituent elements, the charging member 65K, the electrophotographic photosensitive member 61K, the cleaning device 62K, and the developing device 64K for black are integrated into the constituent elements of the process cartridge 100K. Similarly, a charging member 65C, an electrophotographic photosensitive member 61C, a cleaning device 62C, and a developing device 64C for cyan, a charging member 65M, an electrophotographic photosensitive member 61M, and a cleaning device 62M for magenta. The set of the developing unit 64M and the set of the charging member 65Y, the electrophotographic photosensitive member 61Y, the cleaning device 62Y, and the developing unit 64Y for yellow are integrated into the constituent elements of the process cartridges 100C, 100M, and 100Y. ing. By incorporating these four process cartridges into the image forming apparatus 1000 ′, the image forming apparatus 1000 ′ is provided with each part that is a component of these process cartridges. Each of these process cartridges 100K, 100C, 100M, and 100Y corresponds to an example of the process cartridge of the present embodiment.

  In addition, the image forming apparatus 1000 ′ receives an intermediate transfer of the primary transfer image by receiving the transfer (primary transfer) of the toner images of the respective colors formed on the electrophotographic photoreceptors 61K, 61C, 61M, and 61Y. Intermediate transfer belt 5 that is a transfer body, primary transfer rolls 50K, 50C, 50M, and 50Y that perform primary transfer of toner images of each color to the intermediate transfer belt 5, and secondary transfer that performs secondary transfer to paper Four toner cartridges 4K and 4C for supplying toner of respective color components to the roll pair 9, a fixing device 10 'which is a fixing means for fixing the toner image transferred on the sheet, and the four developing devices, respectively. , 4M, 4Y, and sheet feeding means 1 'for storing sheets are also provided.

Here, the intermediate transfer belt 5 circulates and moves in the direction of arrow A in the figure while being stretched between the secondary transfer roll 9b and the drive roll 5a while receiving a driving force from the drive roll 5a.
In the above description, the case where the intermediate transfer belt 5 is used as the intermediate transfer member has been described. However, the intermediate transfer member may have a belt shape like the intermediate transfer belt 5 or a drum shape. Also good.
In the case of a belt shape, a conventionally known resin may be used as the resin material used as the base material of the intermediate transfer member. For example, polyimide resin, polycarbonate resin (PC), polyvinylidene fluoride (PVDF), polyalkylene terephthalate (PAT), ethylenetetrafluoroethylene copolymer (ETFE) / PC, ETFE / PAT, PC / PAT blend material, polyester Resin materials such as polyether ether ketone and polyamide, and resin materials using these as main raw materials. Further, a resin material and an elastic material may be blended and used.

Next, an image forming operation in the image forming apparatus 1000 ′ will be described.
The four electrophotographic photoreceptors 61K, 61C, 61M, and 61Y are charged by charging members 65K, 65C, 65M, and 65Y, respectively, and further receive the laser light emitted from the exposure units 7K, 7C, 7M, and 7Y to receive each electron. An electrostatic latent image is formed on the photographic photoreceptor. The formed electrostatic latent image is developed with an electrostatic latent image developer containing toner of each color by the developing devices 64K, 64C, 64M, and 64Y to form a toner image. The toner images of the respective colors formed in this way are yellow (Y), magenta (M), cyan (C) on the intermediate transfer belt 5 in the primary transfer rolls 50K, 50C, 50M, and 50Y corresponding to the respective colors. ) And black (K) are sequentially transferred (primary transfer) and superposed to form a multicolor primary transfer image.

The multicolor primary transfer image is conveyed to the secondary transfer roll pair 9 by the intermediate transfer belt 5. On the other hand, in response to the formation of the multi-color primary transfer image, the sheet is taken out from the sheet feeding means 1 ′ and conveyed by the conveying roll 3, and the position is adjusted by the alignment roll pair 8. Then, the multi-color primary transfer image is transferred (secondary transfer) to the conveyed paper by the secondary transfer roll pair 9, and further fixed to the secondary transfer image on the paper by the fixing device 10 ′. Processing is performed. After the fixing process, the sheet having the fixed image passes through the delivery roll pair 13 and is discharged to the paper discharge receiver 2.
The above is the description of the image forming operation in the image forming apparatus 1000 ′.

  In the image forming apparatus and the process cartridge according to the present embodiment, the undercoat layer of the electrophotographic photosensitive member contains hollow metal oxide particles to which an acceptor compound is attached, and thus is intended to be used repeatedly. An image in which the generation of small black spots that are not suppressed is suppressed is stably formed.

  Hereinafter, the present embodiment will be specifically described with reference to examples, but the present embodiment is not limited to these examples. In the following description, “part” means “part by mass” unless otherwise specified.

[Example 1]
-Production of hollow zinc oxide particles 1-
By the following procedure, zinc oxide was immobilized on the surface of the hollow particles of the cross-linked polymethyl methacrylate resin using a liquid phase precipitation method.
To a liquid obtained by stirring and dispersing 50 parts by mass of a crosslinked polymethyl methacrylate resin having an average particle size of 0.1 μm in 1000 parts by mass of methanol, 50 parts by mass of zinc-2,4-pentandionate was added, and methanol was stirred. A liquid in which 50 parts by mass and 50 parts by mass of distilled water were mixed was dropped. After completion of the dropwise addition, the mixture was stirred at 55 ° C. for 2 hours, and then the precipitate was separated by pressure filtration and washed with water. Then, it dried under reduced pressure at 100 degreeC for 2 hours, and obtained the bridge | crosslinking type polymethylmethacrylate resin particle with an average particle diameter of 0.1 micrometer which coat | covered the zinc oxide on the surface. Crosslinked polymethyl methacrylate resin particles coated with zinc oxide on the surface were baked in a heating furnace at 550 ° C. for 5 hours to obtain hollow zinc oxide particles having an average particle diameter of 0.1 μm.

-Formation of undercoat layer-
15 parts by mass of hollow zinc oxide particles having an average particle diameter of 0.1 μm obtained as described above, 0.6 parts by mass of alizarin, and blocked isocyanate (Sumidule 3173, manufactured by Sumitomo Bayern Urethane Co., Ltd.) as a curing agent 13 .5 parts by mass and 15 parts by mass of butyral resin (ESREC BM-1, manufactured by Sekisui Chemical Co., Ltd.) in 38 parts by mass of methyl ethyl ketone dissolved in 85 parts by mass and 25 parts by mass of methyl ethyl ketone were mixed into an ultrasonic homogenizer. For 20 minutes to obtain a dispersion. To the obtained dispersion, 0.005 parts by mass of dioctyltin dilaurate and 4.0 parts by mass of silicone resin particles (Tospearl 145, manufactured by GE Toshiba Silicone) are added as a catalyst, and a coating liquid for forming an undercoat layer is added. Obtained. This coating solution was applied on an aluminum substrate having a diameter of 30 mm by a dip coating method, followed by drying and curing at 160 ° C. for 40 minutes to obtain an undercoat layer having a thickness of 25 μm.

-Formation of charge generation layer-
Next, as a charge generation material, it has strong diffraction peaks at Bragg angles (2θ ± 0.2 °) with respect to CuKα characteristic X-rays of at least 7.4 °, 16.6 °, 25.5 ° and 28.3 °. Using a glass bead having a diameter of 1 mm, a mixture of 15 parts by mass of chlorogallium phthalocyanine crystal, 10 parts by mass of vinyl chloride-vinyl acetate copolymer resin (VMCH, manufactured by Nippon Union Carbide) and 300 parts by mass of n-butyl alcohol was used. Then, it was dispersed in a sand mill for 4 hours to obtain a coating solution for forming a charge generation layer. This coating solution for forming a charge generation layer was dip-coated on the undercoat layer and dried to obtain a charge generation layer having a thickness of 0.2 μm.

-Formation of charge transport layer-
Next, a coating solution for forming a charge transport layer was prepared by the following steps.
In a solution obtained by dissolving 0.06 parts by mass of fluorine-based graft polymer GF400 (manufactured by Toagosei Co., Ltd.) in 4.3 parts by mass of toluene, 1.8 parts by mass of tetrafluoroethylene resin particles (average particle size: 0.2 μm) The mixture was stirred and mixed for 48 hours while maintaining the liquid temperature at 20 ° C. to obtain a tetrafluoroethylene resin particle suspension (liquid A).

Next, 9.8 parts by mass of N, N′-bis (3-methylphenyl) -N, N′-diphenylbenzidine as a charge transporting substance, bisphenol Z-type polycarbonate resin (viscosity average molecular weight: 40,000) 13.0 2 parts by mass of 2,6-di-t-butyl-4-methylphenol as an antioxidant are mixed and dissolved in 48.3 parts by mass of tetrahydrofuran and 18.2 parts by mass of toluene. Got.
Dispersion treatment in which the liquid A was added to the liquid B and stirred and mixed, and then the pressure was increased to 500 kgf / cm ² using a high-pressure homogenizer (manufactured by Yoshida Kikai Kogyo Co., Ltd.) equipped with a through-type chamber having fine flow paths. 5 ppm of silicone oil (trade name: manufactured by Shin-Etsu Silicone Co., Ltd.) was added to the solution obtained by repeating 6 times, and the mixture was sufficiently stirred to obtain a coating solution for forming a charge transport layer. This coating solution for forming a charge transport layer was applied onto the charge generation layer and dried at 115 ° C. for 40 minutes to form a charge transport layer having a thickness of 32 μm. Thus, an intended electrophotographic photoreceptor E1 was obtained.

  Using a modified full-color printer Docu Center Color f450 manufactured by Fuji Xerox Co., Ltd., in which the electrophotographic photosensitive member E1 thus obtained is mounted on a drum cartridge, it is 10,000 as described later in an environment of 28 ° C./85% RH. A continuous print test of 100,000 sheets and 100,000 sheets and evaluation of residual potential were performed. The obtained results are shown in Table 2.

[Example 2]
-Production of hollow zinc oxide particles 2-
50 parts by mass of hollow zinc oxide particles having an average particle diameter of 0.1 μm obtained in Example 1 were mixed in 1000 parts by mass of methanol, and N-β (aminoethyl) γ-aminepropyltriethoxysilane was mixed with stirring. A solution prepared by dissolving 8 parts by mass in 25 parts by mass of methanol was added dropwise and stirred at 25 ° C. for 1 hour after the completion of the addition. After completion of stirring, the precipitate was separated by pressure filtration, dried under reduced pressure at 80 ° C. for 2 hours, and hollow zinc oxide particles surface-treated with a silane coupling agent were obtained.

-Production of photoconductor E2-
15 parts by mass of hollow zinc oxide particles having an average particle diameter of 0.1 μm obtained as described above, 1.0 part by mass of alizarin, and blocked isocyanate (Sumidule 3175, manufactured by Sumitomo Bayern Urethane Co., Ltd.) 13 as a curing agent 0.5 parts by mass and 15 parts by mass of butyral resin (ESREC BM-1, manufactured by Sekisui Chemical Co., Ltd.) in 38 parts by mass of methyl ethyl ketone and 25 parts by mass of methyl ethyl ketone are mixed, and an ultrasonic homogenizer is mixed. Was dispersed for 20 minutes to obtain a dispersion. To the obtained dispersion, 0.005 parts by mass of dioctyltin dilaurate and 4.0 parts by mass of silicone resin particles (Tospearl 145, manufactured by GE Toshiba Silicone) are added as a catalyst, and a coating liquid for forming an undercoat layer is added. Obtained. This coating solution was applied on an aluminum substrate having a diameter of 30 mm by a dip coating method, followed by drying and curing at 160 ° C. for 40 minutes to obtain an undercoat layer having a thickness of 25 μm.
In the same manner as in Example 1, a charge generation layer and a charge transport layer were sequentially formed on the undercoat layer to obtain an electrophotographic photoreceptor E2, and the same evaluation was performed. The results are shown in Table 2.

[Example 3]
-Production of hollow titanium oxide particles 3-
While adding 50 parts by mass of titanium tetraisopropoxide to a liquid obtained by stirring and dispersing 50 parts by mass of a crosslinked polymethylmethacrylate resin having a hollow structure with an average particle size of 0.15 μm in 1000 parts by mass of isopropyl alcohol, the mixture is stirred. A liquid in which 50 parts by mass of isopropyl alcohol and 50 parts by mass of distilled water were mixed was dropped. After completion of the dropwise addition, the mixture was stirred at 65 ° C. for 2 hours, and then the precipitate was separated by pressure filtration and washed with water. Thereafter, drying was performed under reduced pressure at 100 ° C. for 2 hours to obtain hollow particles of a crosslinked polymethyl methacrylate resin having an average particle diameter of 0.15 μm and having titanium oxide coated on the surface. Crosslinked polymethylmethacrylate resin particles having titanium oxide coated on the surface were fired in a heating furnace at 600 ° C. for 3 hours to obtain hollow titanium oxide particles having an average particle size of 0.15 μm.

-Production of photoconductor E3-
15 parts by mass of hollow titanium oxide particles having an average particle diameter of 0.1 μm obtained as described above, 3 parts by mass of 4-ethoxy-1,2-dihydroxyanthraquinone, and blocked isocyanate (Sumidule 3175, Sumitomo) as a curing agent. Bayer Urethane Co., Ltd.) 13.5 parts by mass and Butyral Resin (Esreck BM-1, Sekisui Chemical Co., Ltd.) 15 parts by mass were dissolved in 85 parts by mass of methyl ethyl ketone, and 38 parts by mass of methyl ethyl ketone. The mixture was mixed and dispersed with an ultrasonic homogenizer for 30 minutes to obtain a dispersion. To the obtained dispersion, 0.005 parts by mass of dioctyltin dilaurate and 4.0 parts by mass of silicone resin particles (Tospearl 145, manufactured by GE Toshiba Silicone) are added as a catalyst, and a coating liquid for forming an undercoat layer is added. Obtained. This coating solution was applied on an aluminum substrate having a diameter of 30 mm by a dip coating method, followed by drying and curing at 160 ° C. for 40 minutes to obtain an undercoat layer having a thickness of 25 μm.
In the same manner as in Example 1, a charge generation layer and a charge transport layer were sequentially formed on the undercoat layer to obtain an electrophotographic photoreceptor E3, and the same evaluation was performed. The results are shown in Table 2.

-Production of photoconductor E4-
15 parts by mass of hollow silicon oxide particles having an average particle size of 0.1 μm (manufactured by Nippon Steel & Mining Co., Ltd.), 5 parts by mass of benzimidazole perylene, and blocked isocyanate (Sumidu 3175, manufactured by Sumitomo Bayern Urethane Co., Ltd.) as a curing agent 13 0.5 parts by mass and 15 parts by mass of butyral resin (ESREC BM-1, manufactured by Sekisui Chemical Co., Ltd.) in 38 parts by mass of methyl ethyl ketone and 25 parts by mass of methyl ethyl ketone are mixed, and an ultrasonic homogenizer is mixed. Was dispersed for 20 minutes to obtain a dispersion. To the obtained dispersion, 0.005 parts by mass of dioctyltin dilaurate and 4.0 parts by mass of silicone resin particles (Tospearl 145, manufactured by GE Toshiba Silicone) are added as a catalyst, and a coating liquid for forming an undercoat layer is added. Obtained. This coating solution was applied on an aluminum substrate having a diameter of 30 mm by a dip coating method, followed by drying and curing at 160 ° C. for 40 minutes to obtain an undercoat layer having a thickness of 25 μm.
In the same manner as in Example 1, a charge generation layer and a charge transport layer were sequentially formed on the undercoat layer to obtain an electrophotographic photoreceptor E4, and the same evaluation was performed. The results are shown in Table 2.

-Production of hollow zirconium oxide particles 5-
50 parts by mass of zirconium tetrabutoxide is added to a solution obtained by stirring and dispersing 50 parts by mass of a crosslinked polymethyl methacrylate resin having a hollow structure with an average particle size of 0.08 μm in 1000 parts by mass of isopropyl alcohol, and isopropyl while stirring. A liquid in which 50 parts by mass of alcohol and 50 parts by mass of distilled water were mixed was dropped. After completion of the dropwise addition, the mixture was stirred at 65 ° C. for 2 hours, and then the precipitate was separated by pressure filtration and washed with water. Thereafter, drying was performed under reduced pressure at 100 ° C. for 2 hours to obtain hollow particles of a crosslinked polymethyl methacrylate resin having an average particle size of 0.08 μm and having a surface coated with zirconium oxide. Crosslinked polymethylmethacrylate resin particles having a surface coated with zirconium oxide were fired in a heating furnace at 600 ° C. for 3 hours to obtain hollow zirconium oxide particles having an average particle size of 0.08 μm.

-Production of photoconductor E5-
12 parts by mass of hollow zirconium oxide particles having an average particle size of 0.08 μm, 3 parts by mass of purpurin, 13.5 parts by mass of blocked isocyanate (Sumijour 3175, manufactured by Sumitomo Bayern Urethane Co., Ltd.) as a curing agent, and butyral resin (Esreck) (BM-1, manufactured by Sekisui Chemical Co., Ltd.) 15 parts by mass, 38 parts by mass of a solution obtained by dissolving 85 parts by mass of methyl ethyl ketone and 25 parts by mass of methyl ethyl ketone are mixed, and dispersed for 20 minutes with an ultrasonic homogenizer. A liquid was obtained. To the obtained dispersion, 0.005 parts by mass of dioctyltin dilaurate and 4.0 parts by mass of silicone resin particles (Tospearl 145, manufactured by GE Toshiba Silicone) are added as a catalyst, and a coating liquid for forming an undercoat layer is added. Obtained. This coating solution was applied on an aluminum substrate having a diameter of 30 mm by a dip coating method, followed by drying and curing at 160 ° C. for 40 minutes to obtain an undercoat layer having a thickness of 25 μm.
In the same manner as in Example 1, a charge generation layer and a charge transport layer were sequentially formed on the undercoat layer to obtain an electrophotographic photoreceptor E4, and the same evaluation was performed. The results are shown in Table 2.

[Comparative Example 1]
-Production of zinc oxide particles-
100 parts by mass of zinc oxide (average particle size: 70 nm, manufactured by Teica, specific surface area value: 15 m ² / g) is stirred and mixed with 500 parts by mass of methanol, and KBM603 (manufactured by Shin-Etsu Chemical Co., Ltd.) is used as a silane coupling agent. 25 parts by mass was added and stirred for 2 hours. Thereafter, methanol was distilled off under reduced pressure, and baking was performed at 120 ° C. for 3 hours to obtain silane coupling agent surface-treated zinc oxide particles.

-Production of photoconductor C1-
60 parts by mass of the surface-treated zinc oxide particles, 0.6 parts by mass of alizarin, 13.5 parts by mass of blocked isocyanate (Sumidule 3173, manufactured by Sumitomo Bayern Urethane Co., Ltd.) as a curing agent, and butyral resin (BM-1, manufactured by Sekisui Chemical Co., Ltd.) 15 parts by mass, 38 parts by mass of a solution obtained by dissolving 85 parts by mass of methyl ethyl ketone and 25 parts by mass of methyl ethyl ketone are mixed, and 4 hours in a sand mill using glass beads having a diameter of 1 mm. The dispersion liquid was obtained. To the obtained dispersion, 0.005 parts by mass of dioctyltin dilaurate and 4.0 parts by mass of silicone resin particles (Tospearl 145, manufactured by GE Toshiba Silicone) are added as a catalyst, and a coating liquid for forming an undercoat layer is added. Obtained. This coating solution was applied onto an aluminum substrate having a diameter of 30 mm by a dip coating method, followed by drying and curing at 180 ° C. for 40 minutes to obtain an undercoat layer having a thickness of 25 μm.
On the obtained undercoat layer, a charge generation layer and a charge transport layer were sequentially formed in the same manner as in Example 1 to obtain an electrophotographic photoreceptor C1.
The electrophotographic photoreceptor C1 was used and evaluated as described later in the same manner as in Example 1. The obtained results are shown in Table 2.

[Comparative Example 2]
-Production of photoconductor C2-
45 parts by mass of titanium oxide (average particle size: 35 μm, manufactured by Teica, specific surface area value: 40 m ² / g), and 13.5 parts by mass of blocked isocyanate (Sumidule 3173, manufactured by Sumitomo Bayern Urethane) as a curing agent And 38 parts by mass of a solution obtained by dissolving 15 parts by mass of butyral resin (ESLEC BM-1, manufactured by Sekisui Chemical Co., Ltd.) in 85 parts by mass of methyl ethyl ketone and 25 parts by mass of methyl ethyl ketone, and using glass beads having a diameter of 1 mm Then, dispersion was performed for 4 hours with a sand mill to obtain a dispersion. To the obtained dispersion, 0.005 parts by mass of dioctyltin dilaurate and 4.0 parts by mass of silicone resin particles (Tospearl 145, manufactured by GE Toshiba Silicone) are added as a catalyst, and a coating liquid for forming an undercoat layer is added. Obtained. This coating solution was applied onto an aluminum substrate having a diameter of 30 mm by a dip coating method, followed by drying and curing at 180 ° C. for 40 minutes to obtain an undercoat layer having a thickness of 25 μm.
On the obtained undercoat layer, a charge generation layer and a charge transport layer were sequentially formed in the same manner as in Example 1 to obtain an electrophotographic photoreceptor C2.
The electrophotographic photoreceptor C2 was used and evaluated as described later in the same manner as in Example 1. The obtained results are shown in Table 2.

[Comparative Example 3]
-Production of photoconductor C3-
15 parts by mass of a crosslinked polymethylmethacrylate resin having a hollow structure with an average particle size of 0.15 μm, 45 parts by mass of titanium oxide (average particle size: 35 μm, manufactured by Teica, specific surface area value: 40 m ² / g), and curing 13.5 parts by mass of blocked isocyanate (Sumijoule 3173, manufactured by Sumitomo Bayern Urethane Co., Ltd.) and 15 parts by mass of butyral resin (ESLEC BM-1, manufactured by Sekisui Chemical Co., Ltd.) dissolved in 85 parts by mass of methyl ethyl ketone as an agent 38 parts by mass and 25 parts by mass of methyl ethyl ketone were mixed and dispersed for 4 hours with a sand mill using glass beads having a diameter of 1 mm to obtain a dispersion. To the obtained dispersion, 0.005 parts by mass of dioctyltin dilaurate and 4.0 parts by mass of silicone resin particles (Tospearl 145, manufactured by GE Toshiba Silicone) are added as a catalyst, and a coating liquid for forming an undercoat layer is added. Obtained. This coating solution was applied onto an aluminum substrate having a diameter of 30 mm by a dip coating method, followed by drying and curing at 180 ° C. for 40 minutes to obtain an undercoat layer having a thickness of 25 μm.
On the obtained undercoat layer, a charge generation layer and a charge transport layer were sequentially formed in the same manner as in Example 1 to obtain an electrophotographic photoreceptor C3.
The electrophotographic photoreceptor C3 was used and evaluated as described later in the same manner as in Example 1. The obtained results are shown in Table 2.

[Comparative Example 4]
-Production of photoconductor C4-
15 parts by mass of hollow zinc oxide particles having an average particle diameter of 0.1 μm prepared in Example 1, 13.5 parts by mass of blocked isocyanate (Sumidule 3173, manufactured by Sumitomo Bayern Urethane Co., Ltd.) as a curing agent, and butyral resin ( 15 parts by mass of ESREC BM-1, manufactured by Sekisui Chemical Co., Ltd., 38 parts by mass of a solution obtained by dissolving 85 parts by mass of methyl ethyl ketone and 25 parts by mass of methyl ethyl ketone are mixed, and dispersed for 20 minutes with an ultrasonic homogenizer. A dispersion was obtained. To the obtained dispersion, 0.005 parts by mass of dioctyltin dilaurate and 4.0 parts by mass of silicone resin particles (Tospearl 145, manufactured by GE Toshiba Silicone) are added as a catalyst, and a coating liquid for forming an undercoat layer is added. Obtained. This coating solution was applied on an aluminum substrate having a diameter of 30 mm by a dip coating method, followed by drying and curing at 160 ° C. for 40 minutes to obtain an undercoat layer having a thickness of 25 μm.
On the resulting undercoat layer, a charge generation layer and a charge transport layer were sequentially formed in the same manner as in Example 1 to obtain an electrophotographic photoreceptor C4.
The electrophotographic photoreceptor C4 was used and evaluated as described later in the same manner as in Example 1. The obtained results are shown in Table 2.

  Table 1 shows particles (excluding silicone particles) and acceptor compounds contained in the undercoat layer.

Details of evaluation and measurement are as follows.
<Evaluation>
(Measurement of increase in residual potential)
The residual potential on the surface of the electrophotographic photosensitive member is measured in the image formation on the 10,000 sheets, and the residual potential after the first image formation and the residual potential after the image formation on the 10,000th and 100,000th images are obtained. The difference (residual potential after forming the 10,000th image-residual potential after forming the first image) and (residual potential after forming the 100,000th image-residual potential after forming the first image) are obtained, respectively. The amount of increase.
Residual potential measurement is performed by attaching a potential sensor (Model 555P-1 (manufactured by Trek)) to the front surface of the photoconductor rotating toward the photoconductor rotation upstream of the charger on a full-color printer Docu Center Color f450 remodeled by Fuji Xerox. The measurement was performed using Model 334 (manufactured by Trek) as a surface potential meter.

(Evaluation of print quality)
Under 28 ℃ / 85% RH environment, A3 paper (manufactured by Fuji Xerox Co., C ² paper) 100,000 th, and outputs the white image prints and halftone printing, white printing state of generation of minute black spots, half For tone print image quality, the density ratio (%) of the output image with respect to the input image was evaluated.
The results are shown in Table 2.

3 ... transport roll, 4K, 4C, 4M, 4Y ... toner cartridge, 5a ... drive roll, 5 ... intermediate transfer belt, 5 ... intermediate transfer belt, 7a ... static elimination lamp, 7 ... exposure part, 7K, 7C, 7M, 7Y ... Exposure section, 8 ... Roll pair, 9b ... Secondary transfer roll, 9 ... Secondary transfer roll pair, 10 ... Fixer, 13 ... Sending roll pair, 50, 50K, 50C, 50M, 50Y ... Primary transfer roll, 61, 61K, 61C, 61M, 61Y ... electrophotographic photosensitive member, 62, 62K, 62C, 62M, 62Y ... cleaning device, 64, 64K, 64C, 64M, 64Y ... developing devices 65, 65K, 65C, 65M, 65Y ... Charging member, 65a ... power source, 100, 100K, 100C, 100M, 100Y ... process cartridge, 100a ... support member, 101 ... electrophotographic photosensitive member, 102 ... lead Sex support, 103 ... photosensitive layer, 104 ... undercoat layer, 105 ... charge generating layer, 106 ... charge transport layer, 107 ... protective layer, 1000 ... image forming apparatus

Claims (10)

A conductive support;
An undercoating layer that is disposed on the conductive support and includes hollow metal oxide particles and a binder resin in which an acceptor compound is attached to the surface of the hollow particles composed of a metal oxide;
A photosensitive layer disposed on the undercoat layer;
An electrophotographic photosensitive member having:   The electrophotographic photoreceptor according to claim 1, wherein the metal oxide is one or more metal oxides selected from the group consisting of titanium oxide, zinc oxide, aluminum oxide, silicon oxide, tin oxide, and zirconium oxide.   The electrophotographic photoreceptor according to claim 1, wherein the acceptor compound is at least one compound selected from an anthraquinone compound and a perylene compound. The electrophotographic photoreceptor according to any one of claims 1 to 3, wherein the acceptor compound is at least one compound represented by the following general formula (I) or (II).

(In the formula (I), R ^{1 to} R ⁸ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, an amino group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl. Group or carboxyl group.)

(In the formula (II), R ^{a to} R ^b are each independently a hydrogen atom, a halogen atom, a hydroxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a nitro group, a cyano group, an amino group, Or a carboxyl group.) The electrophotographic photoreceptor according to claim 1, wherein the acceptor compound is at least one compound represented by the following general formula (2) or (3).


(In Formula (2), R ⁹ and R ¹⁰ each independently represents a substituted or unsubstituted alkylene group.)

(In Formula (3), R ¹¹ and R ¹² each independently represent a substituted or unsubstituted alkylene group, and R ¹³ and R ¹⁴ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a substituted or unsubstituted group. An alkyl group, a substituted or unsubstituted alkoxy group, a nitro group, a cyano group, an amino group, or a carboxyl group; At least the electrophotographic photoreceptor according to any one of claims 1 to 5,
A process cartridge that is detachable from the image forming apparatus. The electrophotographic photoreceptor according to any one of claims 1 to 5,
Charging means for charging the electrophotographic photoreceptor;
A latent image forming means for forming an electrostatic latent image on the surface of the charged electrophotographic photosensitive member;
Developing means for developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive member with toner to form a toner image;
Transfer means for transferring a toner image formed on the surface of the electrophotographic photosensitive member to a recording medium;
An image forming apparatus.   Hollow metal oxide particles comprising hollow particles composed of a metal oxide and an acceptor compound attached to the surface of the hollow particles. Forming a metal oxide film on the surface of the resin particles;
Firing the resin particles having the metal oxide film formed thereon to remove the resin particles to produce hollow metal oxide particles; and
Attaching an acceptor compound to the surface of the hollow metal oxide particles;
The manufacturing method of the hollow metal oxide particle which has this. Forming a metal oxide film on the surface of the resin particles;
Firing the resin particles having the metal oxide film formed thereon to remove the resin particles to produce hollow metal oxide particles; and
Attaching an acceptor compound to the surface of the hollow metal oxide particles;
A step of forming a subbing layer by applying a coating liquid containing hollow metal oxide particles and a binder resin to which the acceptor compound is adhered on a conductive support, and then drying and curing the coating film;
Providing a photosensitive layer on the undercoat layer;
A process for producing an electrophotographic photosensitive member having