JP6155726B2 - Electrophotographic photosensitive member, process cartridge, and image forming apparatus - Google Patents

Description

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

An electrophotographic image forming apparatus has high speed and high printing quality, and is used in copying machines, laser beam printers, and the like. As photoconductors used in electrophotographic image forming apparatuses, organic photoconductors using organic photoconductive materials are the mainstream, and the structure of the photoconductor is also combined with charge transfer complex structures and charge generation materials. The performance has been improved by changing to a function-separated type photoconductor dispersed in a resin.
In the case of this function-separated type photoreceptor, at present, in many cases, an undercoat layer is first formed on an aluminum substrate, and then a charge generation layer and a charge transport layer are formed.
Regarding the stability of the photoreceptor's potential stability and environmental stability, the stability of the image quality related to the stability of the potential is often dependent not only on the charge generation layer and charge transport layer but also on the undercoat layer, There is a demand for an undercoat layer with small charge accumulation due to repeated use.

  A method of forming a conductive powder-dispersed conductive layer on an aluminum substrate and further forming an undercoat layer is disclosed (for example, see Patent Document 1). In this case, the conductive layer is used to conceal the base material and the resistance is adjusted, so that the undercoat layer has a blocking function (hereinafter sometimes referred to as a conductive layer type).

  Also disclosed is a method of applying a conductive powder dispersion layer on a substrate and using it as an undercoat layer having the functions of a blocking layer and a resistance adjusting layer (hereinafter sometimes referred to as a dispersion-type undercoat layer). (For example, refer to Patent Document 2).

  In addition, the first dispersion-type subbing layer that was put into practical use uses a titanium oxide conductive powder, and the thickness of the subbing layer was set to about 0.03 μm to 0.3 μm (for example, see Patent Document 3). ).

  In addition, a method of controlling the resistance value of the undercoat layer to an appropriate range so as to correspond to changes in temperature and humidity (for example, see Patent Document 4) and a method of adding a small amount of an acceptor to metal oxide particles (for example, a patent) Reference 5) is disclosed.

Japanese Patent Laid-Open No. 05-11483 JP 2002-123028 A Japanese Patent Laid-Open No. 05-80572 JP 2003-186219 A JP 2006-30698 A

  An object of the present invention is to provide an electrophotographic photosensitive member having a long lifetime.

Specific means for achieving the above object are as follows.
That is, the invention according to claim 1
A conductive substrate having a surface comprising aluminum;
An intermediate layer formed on the surface of the conductive substrate containing aluminum, containing tin oxide particles or zinc oxide particles and a binder resin as metal oxide particles, and an amine content of 0.1% by mass or less;
An undercoat layer formed on the intermediate layer and containing an organometallic compound having an amino group;
A photosensitive layer formed on the undercoat layer;
I have a,
The intermediate layer is an electrophotographic photoreceptor containing an anthraquinone derivative represented by the following general formula (1) .

The invention according to claim 2
The electrophotographic photosensitive member according to claim 1, wherein the metal oxide particles are surface-treated with a silane coupling agent having no amino group.

The invention according to claim 3
3. The electrophotographic photosensitive member according to claim 1, wherein the volume average particle diameter of the metal oxide particles is 10 nm or more and 100 nm or less.

(In the general formula (1), n1 is 2 or 3, n2 is .m 1 represents 0 represents 0 or 1, m @ 2 0 Table to .R ¹ and ^{R 2} are each independently carbon number Represents an alkoxy group of 1 or more and 10 or less, provided that when n1 is 2, m1 represents 1, and when n1 is 3, m1 represents 0.

The invention according to claim 4
The electrophotographic photosensitive member according to any one of claims 1 to 3 ,
It is a process cartridge that can be attached to and detached from the image forming apparatus.

The invention according to claim 5
5. The process cartridge according to claim 4 , further comprising contact charging type charging means for charging the surface of the electrophotographic photosensitive member.

The invention according to claim 6
The electrophotographic photosensitive member according to any one of claims 1 to 3 ,
Charging means for charging the surface of the electrophotographic photosensitive member;
An electrostatic 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 according to claim 7 provides:
The image forming apparatus according to claim 6 , wherein the charging unit is a contact charging type charging unit.

According to the first to third aspects of the present invention, an electrophotographic photosensitive member having a long life is provided as compared with the case where the amine content in the intermediate layer exceeds 0.1% by mass.
According to the inventions according to claims 4 to 5, there is provided a process cartridge provided with an electrophotographic photosensitive member having a long life as compared with the case where the content of amine in the intermediate layer exceeds 0.1% by mass. .
According to the inventions according to claims 6 to 7, there is provided an image forming apparatus provided with an electrophotographic photosensitive member having a long life as compared with a case where the content of amine in the intermediate layer exceeds 0.1% by mass. The

It is sectional drawing which concerns on the photoconductor of this embodiment. It is sectional drawing which concerns on the photoconductor of this embodiment. It is sectional drawing which concerns on the photoconductor of this embodiment. It is sectional drawing which concerns on the photoconductor of this embodiment. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment. 1 is a schematic configuration diagram illustrating an example of a contact charging type image forming apparatus using an electrophotographic photosensitive member according to an exemplary embodiment. In an Example, it is a schematic diagram which shows the chart used by ghost evaluation.

  Hereinafter, embodiments of the electrophotographic photosensitive member, the process cartridge, and the image forming apparatus of the present invention will be described in detail.

<Electrophotographic photoreceptor>
The electrophotographic photoreceptor of this embodiment (hereinafter also referred to as “photoreceptor”) is formed on a conductive substrate having a surface containing aluminum, and on the surface of the conductive substrate containing aluminum. An intermediate layer containing oxide particles and a binder resin and having an amine content of 0.1% by mass or less; an undercoat layer formed on the intermediate layer and containing an organometallic compound having an amino group; And a photosensitive layer formed on the pulling layer.

In the present embodiment, “amine” refers to a compound in which at least one hydrogen atom of ammonia is substituted with a hydrocarbon residue. The hydrocarbon residue may contain other elements other than carbon and hydrogen.
The “organometallic compound having an amino group” in the present embodiment may be any of primary amine, secondary amine, tertiary amine, and quaternary ammonium ion.

The electrophotographic photosensitive member of this embodiment has a long life. The reason for this is not necessarily clear, but is presumed as follows.
Since compounds containing amino groups have excellent charge blocking properties, an electrophotographic photosensitive layer can be obtained by interposing a layer containing an amino group containing compound (undercoat layer) between the aluminum substrate and the photosensitive layer. The blocking resistance of the body is improved. However, when a compound containing an amino group comes into contact with the aluminum substrate, it is considered that the aluminum substrate is corroded by an electrochemical reaction to increase the resistance value at the interface between the undercoat layer and the aluminum substrate. It is considered that corrosion of the aluminum substrate may occur in all amines including compounds containing amino groups. In particular, the tendency tends to become remarkable under high temperature and high humidity. By making the undercoat layer into a two-layer structure of a layer containing an amine content (organic metal compound) and a layer having an amine content of 0.1% by mass or less in order from the surface of the aluminum substrate, the aluminum substrate It is presumed that the life of the electrophotographic photosensitive member is extended because the degree of contact between the base and the amine is reduced and corrosion of the aluminum substrate is prevented.

The photoreceptor of this embodiment will be described with reference to the drawings. 1 to 4 are sectional views according to the photoconductor of this embodiment. In addition, the same code | symbol shall be attached | subjected to the same component in each drawing, and description is abbreviate | omitted.
The photoreceptor in FIG. 1 includes an intermediate layer containing metal oxide particles and a binder resin on an aluminum-containing surface of a conductive substrate 1 having an aluminum-containing surface, and an amine content of 0.1% by mass or less. 21, an undercoat layer 22 formed on the intermediate layer 21 and containing an organometallic compound having an amino group, and a photosensitive layer 3 formed on the undercoat layer 22.

In addition to the configuration shown in FIG. 1, the photosensitive layer 3 may have a two-layer structure including a charge generation layer 31 and a charge transport layer 32 (FIG. 2). A protective layer 5 may be provided (FIG. 3). Furthermore, the photosensitive layer may have a two-layer structure of the charge generation layer 31 and the charge transport layer 32, and the protective layer 5 may be provided on the charge transport layer 32 (FIG. 4). 2 and 4, the charge generation layer 31 and the charge transport layer 32 are arranged in this order from the conductive substrate 1 side. However, the charge transport layer 32 and the charge generation layer 31 may be arranged in this order from the conductive substrate 1 side. .
Hereinafter, each layer such as a conductive substrate and an undercoat layer applied to the present embodiment will be described.

(Conductive substrate)
The conductive substrate used in the present embodiment is not particularly limited as long as it has a surface containing aluminum. A specific example of the conductive substrate is an aluminum drum. Moreover, you may use what vapor-deposited aluminum on paper, plastic, or glass, and formed the layer which has aluminum on the surface.
The shape of the conductive substrate is not limited to a drum shape, and may be a sheet shape or a plate shape. In addition, when the conductive substrate is an aluminum pipe, the surface may be left as it is, or a treatment such as mirror cutting, etching, anodizing, rough cutting, centerless grinding, sand blasting, wet honing, etc. in advance. May be performed.

In the present embodiment, that the substrate is “conductive” means that the volume resistivity of the substrate is less than 10 ¹³ Ωcm.

(Middle layer)
The intermediate layer used in this embodiment may be a layer containing metal oxide particles and a binder resin and having an amine content of 0.1% by mass or less, and there is no particular limitation on the configuration thereof. Reactive acceptor materials and the like. In this embodiment, the reactive acceptor material refers to a material that chemically reacts with the surface of the metal oxide particles contained in the intermediate layer or a material that adsorbs to the surface of the metal oxide particles, and is selected as the surface of the metal oxide particles. Refers to a material that can be present.
The intermediate layer is configured as a layer having an amine content of 0.1% by mass or less, and does not deny the presence of amine contained as an impurity in each component constituting the intermediate layer described later. The content of amine in the intermediate layer is preferably 0.1% by mass or less, and ideally 0% by mass.
The amine content in the intermediate layer is measured, for example, by the following method.
After pulverizing the intermediate layer, there are an FT-IR method and an FT-IR method by extracting it into a solvent.

  The intermediate layer preferably has a thickness of 15 μm to 30 μm, and more preferably 20 μm to 25 μm. Further, the Vickers strength of the intermediate layer is preferably 35 or more, and more preferably 40 or more.

  As the metal oxide particles used in the present embodiment, conductive powder having a particle size of 10 nm to 100 nm is preferably used. The particle size here means an average primary particle size. When the particle diameter is 10 nm or more, the surface area of the metal oxide particles does not become too large, and it becomes easy to obtain a uniform dispersion. When the particle size is 100 nm or less, the secondary particles or higher particles are expected to have a particle size of 1 μm or less, and a portion where the metal oxide particles are present and not present in the intermediate layer, a so-called sea-island structure. Image quality defects such as non-uniform halftone density are less likely to occur.

The intermediate layer needs to obtain an appropriate impedance at a frequency corresponding to the electrophotographic process speed. Therefore, the metal oxide particles should have a powder resistance of 10 ⁴ Ω · cm or more and 10 ¹⁰ Ω · cm or less. Is preferred. In particular, it is preferable to use at least one metal oxide particle selected from the group consisting of tin oxide, titanium oxide, and zinc oxide having the above resistance value. When the resistance value of the metal oxide particles is 10 ⁴ Ω · cm or more, the slope of the dependency of the impedance on the amount of added particles becomes small, and the impedance can be easily controlled. If the resistance value of the metal oxide particles is 10 ¹⁰ Ω · cm or less, the residual potential is hardly increased.

  The solid content of the metal oxide particles in the intermediate layer is preferably 30% by mass or more and 60% by mass or less, and more preferably 35% by mass or more and 55% by mass or less from the viewpoint of maintaining electric characteristics.

  The metal oxide particles used in the present embodiment may be surface-treated using an organic compound such as a silane coupling agent that does not have an amino group. When the silane coupling treatment is performed, the dispersibility of the metal oxide particles is often improved. Specific examples of the coupling agent include vinyltrimethoxysilane, 3-methacryloxypropyl-tris (2-methoxyethoxy) silane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and 3-glycid. Examples thereof include silane coupling agents such as xylpropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-chloropropyltrimethoxysilane.

  The treatment amount of the coupling agent is preferably 0.1% by mass or more and 3% by mass or less, more preferably 0.3% by mass or more and 2.0% by mass or less, more preferably, based on the metal oxide particles. It is 0.5 mass% or more and 1.5 mass% or less.

In addition, the processing amount of a coupling agent is measured as follows.
There are analysis methods such as FT-IR method, 29Si solid state NMR method, thermal analysis, XPS, etc., but FT-IR method is simple. In the FT-IR method, the normal KBr tablet method or the ATR method may be used. A small amount of the treated metal oxide particles are mixed with KBr and the FT-IR is measured to measure the throughput of the coupling agent.

  These metal oxide particles may be subjected to a heat treatment after surface treatment with the above-mentioned coupling agent to improve the environmental dependency of the resistance value, if necessary. The heat treatment temperature is preferably 150 ° C. to 300 ° C., and the treatment time is preferably 30 minutes to 5 hours.

Examples of the binder resin used in this embodiment include acetal resins such as polyvinyl butyral, polyvinyl alcohol resin, casein, cellulose resin, gelatin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, and vinyl chloride. Polymer resin compounds such as vinyl acetate-maleic anhydride copolymer resin, silicone resin, silicone-alkyd resin, phenol resin, phenol-formaldehyde resin, and the like are used. These polymer resin compounds may be used alone or in combination of two or more.
As the binder resin, an acetal resin is preferable, and polyvinyl butyral is more preferable.

  The intermediate layer may contain a reactive acceptor material as necessary. Specific examples of reactive acceptor materials include quinone, anthraquinone, coumarin, phthalocyanine, triphenylmethane, anthocyanin, flavone, fullerene, ruthenium complex, xanthene, benzoxazine, and porphyrin materials. In view of the safety, availability, and electron transport capability of the material, an anthraquinone-based material (anthraquinone derivative) is preferable.

  The amount of the reactive acceptor material added is determined by the surface area of the metal oxide particles that are a chemical reaction or adsorption partner, and the electron transport ability of each material, but is usually 0.01 to the mass of the metal oxide particles. It is used in the range of mass% to 20 mass%. More preferably, it is used in the range of 0.1% by mass to 10% by mass. If the addition amount is 0.01% by mass or more, the effect of the acceptor is exhibited. On the other hand, if the addition amount is 20% by mass or less, it becomes difficult to cause aggregation between the metal oxide particles, the distribution of the metal oxide particles in the intermediate layer is likely to be uniform, and a good conductive path is likely to be formed. The residual potential is unlikely to rise and black spots and non-uniform halftone density are less likely to occur.

  When an anthraquinone derivative is used as the reactive acceptor material, the anthraquinone derivative is preferably a compound represented by the following general formula (1).

In the general formula (1), n1及Beauty n2 represents 0 to 3 each independently integers. However, at least one of n1 and n2 represents an integer of 1 or more and 3 or less (that is, neither n1 nor n2 represents 0). m1 and m2 each independently represent an integer of 0 or 1. R ¹ and R ² each independently represents an alkyl group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms.

  Moreover, as a reactive acceptor material, the compound represented by following General formula (2) may be sufficient.

In general formula (2), n1, n2, n3, and n4 each independently represent an integer of 0 or more and 3 or less. However, at least one of n1, n2, n3, and n4 represents an integer of 1 or more and 3 or less (that is, n1, n2, n3, and n4 do not represent 0). m1 and m2 each independently represent an integer of 0 or 1. r represents an integer of 2 or more and 10 or less. R ¹ and R ² each independently represents an alkyl group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms.

Here, in the general formulas (1) and (2), the alkyl group having 1 to 10 carbon atoms represented by R ¹ and R ² may be either linear or branched, for example, a methyl group , Ethyl group, propyl group, isopropyl group and the like. The alkyl group having 1 to 10 carbon atoms is preferably an alkyl group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms.
The alkoxy group (alkoxyl group) having 1 to 10 carbon atoms represented by R ¹ and R ² may be linear or branched, for example, methoxy group, ethoxy group, propoxy group, isopropoxy group Etc. The alkoxy group having 1 to 10 carbon atoms is preferably an alkoxy group having 1 to 8 carbon atoms, more preferably an alkoxy group having 1 to 6 carbon atoms.

  Specific examples of the reactive acceptor material are shown below, but are not limited thereto. In the following specific examples, Me represents a methyl group, Et represents an ethyl group, and Bu represents a butyl group.

Further, when coherent light such as a laser is used for the exposure apparatus, it is necessary to prevent moire images. For this purpose, the surface roughness of the intermediate layer is adjusted to ¼n (n is the refractive index of the upper layer) or more and ½λ or less of the exposure laser wavelength λ used.
The surface roughness may be adjusted by adding resin balls in the intermediate layer. As the resin ball, silicone resin, cross-linked PMMA resin, or the like may be used.
The intermediate layer may contain other components other than the above components.

  In forming the intermediate layer, a coating solution for forming an intermediate layer in which the above components are added to a solvent is used. The above-described metal oxide particles premixed or predispersed may be dispersed in a binder resin to obtain a coating solution for forming an intermediate layer. You may add the reactive acceptor material other component mentioned above to the coating liquid for intermediate | middle layer formation.

  As a solvent used for obtaining a coating solution or dispersion for forming an intermediate layer, a known organic solvent capable of dissolving the above-described binder resin, for example, alcohol-based, aromatic-based, halogenated hydrocarbon-based, ketone-based, ketone Alcohol-based, ether-based and ester-based solvents may be used. These solvents may be used alone or in combination of two or more.

  As a method for dispersing the metal oxide particles, a known dispersion method can be used. Examples thereof include a roll mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker.

  As a coating method for the intermediate layer forming coating solution, a known coating method such as a dip coating method, a blade coating method, a wire bar coating method, a spray coating method, a bead coating method, an air knife coating method, or a curtain coating method may be used. Good.

(Underlayer)
The undercoat layer used in this embodiment may be configured as a layer containing an organometallic compound having an amino group (hereinafter sometimes referred to as a specific compound), and other components such as a binder resin may be used. May be included.
The undercoat layer serves as an electrical blocking layer in addition to improving the wettability of the upper photosensitive layer and the like. Therefore, the thickness of the undercoat layer is in the range of 0.1 μm or more and 3 μm or less so that the electrical barrier becomes too strong due to the film thickness being too large and causing a potential increase due to desensitization or repetition. It may be set.
By providing an undercoat layer between the intermediate layer and the photosensitive layer, the electrical characteristics, image quality, image quality maintenance, photosensitive layer adhesion, and the like are improved.

Examples of the specific compound contained in the undercoat layer include organometallic compounds containing a zirconium atom, a titanium atom, an aluminum atom, a manganese atom, a silicon atom, and the like. These compounds may be used alone or as a mixture or polycondensate of a plurality of compounds.
Among them, an organometallic compound containing a zirconium atom or a silicon atom is excellent in performance such as a low residual potential, a small potential change due to the environment, and a small potential change due to repeated use.

Examples of the specific compound containing a silicon atom include 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3- (2-aminoethylamino) propyltrimethoxysilane, and 3- (2-aminoethyl). Amino) propylmethyldimethoxysilane, N, N-bis (2-hydroxyethyl) -3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, and the like.
Of these, silicon compounds preferably used include 3- (2-aminoethylamino) propyltrimethoxysilane, 3- (2-aminoethylamino) propylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, and 3-amino. Examples of the silane coupling agent include propyltrimethoxysilane and N-phenyl-3-aminopropyltrimethoxysilane.

  Examples of the specific compound containing a zirconium atom include zirconium triethanolamine.

  Examples of the specific compound containing a titanium atom include titanium triethanolamate.

In this embodiment, other organometallic compounds other than the specific compound may be used in combination with the specific compound.
Other organometallic compounds containing silicon atoms include, for example, vinyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, vinyltris (2-methoxyethoxysilane), 3-methacryloxypropyltrimethoxysilane, 3-methacryl Oxypropyl-tris (2-methoxyethoxy) silane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, Examples include 3-chloropropyltrimethoxysilane. Among these, vinyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, vinyltris (2-methoxyethoxysilane), 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2- ( Silane coupling agents such as 3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-chloropropyltrimethoxysilane are preferred.

  Examples of other organometallic compounds containing a zirconium atom include acetylacetone zirconium butyrate, zirconium butoxide, zirconium zirconium acetoacetate, acetylacetonate zirconium butoxide, ethyl acetoacetate zirconium butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, Zirconium phosphonate, zirconium octoate, zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like. Among these, acetylacetone zirconium butyrate is preferable.

  Other organometallic compounds containing titanium atoms include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate , Titanium lactate ammonium salt, titanium lactate, titanium lactate ethyl ester, polyhydroxy titanium stearate and the like. Among these, tetraisopropyl titanate is preferable.

  Examples of other organometallic compounds containing aluminum atoms include aluminum isopropylate, monobutoxy aluminum diisopropylate, aluminum butyrate, diethyl acetoacetate aluminum diisopropylate, and aluminum tris (ethyl acetoacetate). Among these, aluminum isopropylate is preferable.

  When the other organometallic compound is used in combination, the proportion of the specific compound in the total organometallic compound is preferably 30% by mass or more and 70% by mass or less, and more preferably 40% by mass or more and 60% by mass or less.

  The undercoat layer may contain a binder resin in order to ensure the film thickness. As the binder resin, a binder resin used in the intermediate layer may be used.

  The proportion of the specific compound in the solid content of the undercoat layer is preferably 5% by mass to 30% by mass, and more preferably 10% by mass to 20% by mass.

In forming the undercoat layer, an undercoat layer forming coating solution in which the above components are added to a solvent is used.
As the solvent used for obtaining the coating solution for forming the undercoat layer, a known organic solvent capable of dissolving the above-described binder resin may be used. Specific examples of the organic solvent include the solvents exemplified in the section of the intermediate layer.

  As a coating method of the coating liquid for forming the undercoat layer, a known coating method such as a dip coating method, a blade coating method, a wire bar coating method, a spray coating method, a bead coating method, an air knife coating method, or a curtain coating method is used. Also good.

(Photosensitive layer)
The photosensitive layer used in the present embodiment may be configured as a function-integrated type photosensitive layer having both charge transport capability and charge generation capability, or a function-separated type photosensitive layer including a charge generation layer and a charge transport layer. It may be configured as.
In the following, a function separation type photosensitive layer will be described as an example.

<Charge generation layer>
The charge generation layer constituting the photosensitive layer is formed by vacuum-depositing a charge generation material on the undercoat layer, or by dispersing or dissolving the charge generation material together with an organic solvent and a binder resin and applying it on the undercoat layer. It may be formed.

  In this embodiment, any material can be used as the charge generation material as long as it is a known charge generation material, but particularly excellent performance can be obtained, and a phthalocyanine pigment is preferably used as the charge generation material. By using a phthalocyanine pigment as a charge generating material, an electrophotographic photoreceptor having particularly high sensitivity and excellent repeat stability can be obtained. In addition, these organic pigments generally have several crystal forms, and any of these crystal forms may be used as long as it is a pigment capable of obtaining a sensitivity suitable for the purpose.

Specific examples of charge generating materials that are particularly preferably used are shown below.
Examples of the charge generating material include phthalocyanine pigments such as metal-free phthalocyanine, chlorogallium phthalocyanine, hydroxygallium phthalocyanine, dichlorotin phthalocyanine, and titanyl phthalocyanine. Chlorogallium phthalocyanine crystal having strong diffraction peaks at least at 7.4 °, 16.6 °, 25.5 ° and 28.3 °, Bragg angle (2θ ± 0.2 °) to CuKα characteristic X-ray of at least 7. Metal-free phthalocyanine crystals having strong diffraction peaks at 7 °, 9.3 °, 16.9 °, 17.5 °, 22.4 ° and 28.8 °, Bragg angle (2θ ± 0. 2 °) at least 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, 25 Hydroxygallium phthalocyanine crystals having strong diffraction peaks at 1 ° and 28.3 °, Bragg angles (2θ ± 0.2 °) with respect to CuKα characteristic X-rays of at least 9.6 °, 24.1 ° and 27.2 ° A titanyl phthalocyanine crystal having a strong diffraction peak can be mentioned.

  The proportion of the charge generation material in the solid content of the charge generation layer is preferably 40% by mass to 60% by mass, and more preferably 45% by mass to 55% by mass.

The charge generation material used in the present embodiment is a dry-type mechanically pulverized pigment crystal produced by a known method using an automatic mortar, planetary mill, vibration mill, CF mill, roller mill, sand mill, kneader, or the like. After the pulverization, it is manufactured by performing a wet pulverization process using a ball mill, a mortar, a sand mill, a kneader or the like together with a solvent. Solvents used in the above treatment include aromatics (toluene, chlorobenzene, etc.), amides (dimethylformamide, N-methylpyrrolidone, etc.), aliphatic alcohols (methanol, ethanol, butanol, etc.), aliphatic poly Monohydric alcohols (ethylene glycol, glycerin, polyethylene glycol, etc.), aromatic alcohols (benzyl alcohol, phenethyl alcohol, etc.), esters (ethyl acetate, butyl acetate, etc.), ketones (acetone, methyl ethyl ketone, etc.), dimethyl sulfoxide, Examples thereof include ethers (diethyl ether, tetrahydrofuran, etc.), several mixed systems, and mixed systems of water and these organic solvents. The solvent to be used is used in the range of 1 to 200 parts by mass, preferably 10 to 100 parts by mass with respect to 100 parts by mass of the pigment crystal. The treatment temperature is 0 ° C. to the boiling point of the solvent, preferably 10 ° C. to 60 ° C. In addition, grinding aids such as salt and sodium nitrate may be used during grinding. The grinding aid may be used in an amount of 0.5 to 20 times, preferably 1 to 10 times the mass of the pigment.
In addition, the pigment crystal produced by a known method may be controlled by combining acid pasting or acid pasting with dry pulverization or wet pulverization as described above. The acid used for acid pasting is preferably sulfuric acid, and a concentration of 70% by mass or more and 100% by mass or less, preferably 95% by mass or more and 100% by mass or less is used, and the dissolution temperature is −20 ° C. or more and 100 ° C. or less. Is more preferable, and is more preferably set in a range of 0 ° C. or more and 60 ° C. or less. The amount of concentrated sulfuric acid is set in the range of 1 to 100 times, preferably 3 to 50 times, based on the mass of the pigment crystal. As a solvent to be precipitated, water or a mixed solvent of water and an organic solvent is used in an arbitrary amount. The temperature for precipitation is not particularly limited, but it is preferably cooled with ice or the like in order to prevent heat generation.

The binder resin used for the charge generation layer is selected from a wide range of insulating resins. Moreover, you may select from organic photoconductive polymers, such as poly-N-vinyl carbazole, polyvinyl anthracene, polyvinyl pyrene, polysilane.
Preferred binder resins include polyvinyl acetal resins, polyarylate resins (polycondensates of bisphenol A and phthalic acid, etc.), polycarbonate resins, polyester resins, phenoxy resins, vinyl chloride-vinyl acetate copolymers, polyamide resins, acrylic resins, Examples of the insulating resin include, but are not limited to, polyacrylamide resin, polyvinyl pyridine resin, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol resin, and polyvinyl pyrrolidone resin. These binder resins may be used alone or in combination of two or more. Of these, polyvinyl acetal resin is particularly preferably used.

  The blending ratio (weight ratio) between the charge generating material and the binder resin is preferably in the range of 10: 1 to 1:10.

Various additives may be added to the charge generation layer in order to improve electrical characteristics and image quality.
Examples of additives include quinone compounds such as chloranil, bromoanil and anthraquinone, tetracyanoquinodimethane compounds, 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitro-9-fluorenone and the like. Fluorenone compounds such as 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole and 2,5-bis (4-naphthyl) -1,3,4- Oxadiazole, oxadiazole compounds such as 2,5-bis (4-diethylaminophenyl) -1,3,4 oxadiazole, xanthone compounds, thiophene compounds, 3,3 ′, 5,5 ′ tetra- Electron transport materials such as diphenoquinone compounds such as t-butyldiphenoquinone, electron transport pigments such as polycyclic condensation systems and azo systems, zirconium chelate compounds , Titanium chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, there can be used a known material such as a silane coupling agent.

Examples of silane coupling agents include vinyltrimethoxysilane, 3-methacryloxypropyl-tris (2-methoxyethoxy) silane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyl Trimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3- (2-aminoethylamino) propyltrimethoxysilane, 3- (2-aminoethylamino) propylmethyl Examples include dimethoxysilane, N, N-bis (2-hydroxyethyl) -3-aminopropyltriethoxysilane, and 3-chloropropyltrimethoxysilane.
Examples of zirconium chelate compounds include zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl zirconium acetoacetate, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate, naphthene. Zirconate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.

Examples of titanium chelate compounds include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium salt, Examples include titanium lactate, titanium lactate ethyl ester, titanium triethanolamate, and polyhydroxytitanium stearate.
Examples of the aluminum chelate compound include aluminum isopropylate, monobutoxy aluminum diisopropylate, aluminum butyrate, diethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate) and the like.
These compounds may be used alone, as a mixture of a plurality of compounds or as a polycondensate.

When forming the charge generation layer, a coating solution for forming a charge generation layer in which the above components are added to a solvent is used.
As a solvent for adjusting the coating solution for forming the charge generation layer, a known organic solvent that dissolves the binder resin is used. For example, it is arbitrarily selected from alcohol organic solvents, aromatic organic solvents, halogenated hydrocarbon organic solvents, ketone organic solvents, ketone alcohol organic solvents, ether organic solvents, ester organic solvents, and the like.
Specific examples of the organic solvent include, for example, methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, acetic acid. Examples include ordinary organic solvents such as n-butyl, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, and toluene.
The organic solvents are used alone or in combination of two or more.
As a method for preparing the charge generation layer forming coating solution, a roll mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a colloid mill, a paint shaker, or the like may be used. When preparing the coating solution for forming the charge generation layer, it is effective to make the particles in the coating solution have a particle size of 0.5 μm or less, preferably 0.3 μm or less, more preferably 0.15 μm or less.

  As a coating method used when providing the charge generation layer, a usual method such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, or a curtain coating method should be used. Can do.

<Charge transport layer>
The charge transport layer constituting the photosensitive layer may be formed by dispersing or dissolving a charge transport material together with a solvent and a binder resin and applying it. If necessary, additives such as an antioxidant and a light stabilizer may be added to the coating solution containing a charge transport material and the like.

  As the charge transport material contained in the charge transport layer, any known material may be used, but the following can be exemplified. For example, oxadiazole derivatives such as 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole, 1,3,5-triphenyl-pyrazoline, 1- [pyridyl- (2)] Pyrazoline derivatives such as -3- (p-diethylaminostyryl) -5- (p-diethylaminostyryl) pyrazoline, triphenylamine, tri (p-methyl) phenylamine, N, N′-bis (3,4-dimethylphenyl) ) Aromatic tertiary amino compounds such as biphenyl-4-amine, dibenzylaniline, 9,9-dimethyl-N, N′-di (p-tolyl) fluorenon-2-amine, N, N′-diphenyl- Aromatic tertiary diamino compounds such as N, N′-bis (3-methylphenyl) -1,1′-biphenyl-4,4′-diamine, 3- (4′dimethyl) 1,2,4-triazine derivatives such as (laminophenyl) -5,6-di- (4′-methoxyphenyl) -1,2,4-triazine, 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone, 4 -Hydrazone derivatives such as diphenylaminobenzaldehyde-1,1-diphenylhydrazone, [p- (diethylamino) phenyl] (1-naphthyl) phenylhydrazone, quinazoline derivatives such as 2-phenyl-4-styryl-quinazoline, 6-hydroxy- Benzofuran derivatives such as 2,3-di (p-methoxyphenyl) -benzofuran, α-stilbene derivatives such as p- (2,2-diphenylvinyl) -N, N′-diphenylaniline, enamine derivatives, N-ethylcarbazole Carbazole derivatives such as poly-N-vinyl Hole transport materials such as carbazole and its derivatives, quinone compounds such as chloranil, bromoanil and anthraquinone, tetracyanoquinodimethane compounds, 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitro- Fluorenone compounds such as 9-fluorenone, 2- (4-biphenyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole and 2,5-bis (4-naphthyl) -1, Oxadiazole compounds such as 3,4-oxadiazole and 2,5-bis (4-diethylaminophenyl) 1,3,4 oxadiazole, xanthone compounds, thiophene compounds, 3,3 ′, 5,5 'Main chain of electron transport material such as diphenoquinone compound such as tetra-t-butyldiphenoquinone, or a group derived from the compound shown above It is like polymer having in the side chain. These charge transport materials are used singly or in combination of two or more.

  The ratio of the charge transport material to the solid content of the charge transport layer is preferably 30% by mass to 60% by mass, and more preferably 40% by mass to 50% by mass.

  Any binder resin may be used as long as it is a known binder resin for the charge transport layer, but an electrically insulating resin capable of forming a film is preferable. For example, polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, vinyl chloride-acetic acid Vinyl copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone-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, carboxymethyl cellulose, vinylidene chloride polymer wax, polyurea Emissions, and the like, but not limited thereto. These binder resins are used singly or in combination of two or more, but in particular, polycarbonate resins, polyester resins, methacrylic resins, and acrylic resins are compatible with charge transport materials, solubility in solvents, and strength. Excellent and preferably used. The mixing ratio (weight ratio) between the binder resin and the charge transport material can be arbitrarily set in any case.

  Additives such as antioxidants, light stabilizers, and heat stabilizers are added to the charge transport layer to prevent photoconductor deterioration caused by ozone, oxidizing gas, light, or heat generated in the image forming apparatus. May be.

  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-tert-butyl-4′-hydroxy-phenyl) propionate] -methane, 3,9-bis [2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1 , 1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane. 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 phosfte, 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 is obtained by using them together with primary antioxidants such as phenolic or amine-based antioxidants.

Examples of the light stabilizer include benzophenone, benzotriazole, dithiocarbamate, and tetramethylpiperidine derivatives.
Examples of the benzophenone light stabilizer include 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, and 2,2′-di-hydroxy-4-methoxybenzophenone. 2- (2′-hydroxy-5′-methylphenyl) -benzotriazole, 2- [2′-hydroxy-3 ′-(3 ″, 4 ″, 5 ″, 6) as a benzotriazole-based light stabilizer '' -Tetra-hydrophthalimido-methyl) -5'-methylphenyl] -benzotriazole, 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2 -(2'-hydroxy-3'-t-butyl-5'-methylphenyl-)-5-chlorobenzotriazole, 2- (2'-hydroxy-3 ', 5'-t-butylphenyl-)-benzo And triazole, 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.

The charge transport layer may contain at least one electron accepting substance for the purpose of improving sensitivity, reducing residual potential, and reducing fatigue during repeated use.
Examples of the electron-accepting substance that may be used in this embodiment include succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrabromophthalic anhydride, tetracyanoethylene, tetracyanoquinodimethane, o -Dinitrobenzene, m-dinitrobenzene, chloranil, dinitroanthraquinone, trinitrofluorenone, picric acid, o-nitrobenzoic acid, p-nitrobenzoic acid, phthalic acid and the like. Of these, fluorenone-based, quinone-based, and benzene derivatives having an electron-withdrawing substituent such as Cl, CN, NO ₂ are particularly preferable.

  Silicone oil may be added to the coating solution as a leveling agent for improving the smoothness of the coating film.

  In consideration of a decrease in electrical characteristics and a decrease in film strength of the charge transport layer, the thickness of the charge transport layer is preferably 5 μm or more and 50 μm or less, more preferably 10 μm or more and 35 μm or less.

  As a coating method used when the charge transport layer is provided, usual methods such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, and a curtain coating method are used. . As a solvent used for coating, ordinary organic solvents such as dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene and toluene may be used alone or in admixture of two or more.

(Protective layer)
In the photoreceptor of this embodiment, a protective layer may be provided on the photosensitive layer as necessary.
The protective layer used in the present embodiment is used for preventing a chemical change of the charge transport layer upon charging or further improving the mechanical strength of the photosensitive layer in a photoreceptor having a laminated structure. As this protective layer, a known protective layer may be used.

  As the protective layer, a layer including a crosslinked product (cured product) is preferably applied. Examples of these layers include well-known configurations such as a cured layer of a composition containing a reactive charge transport material and, if necessary, a curable resin, and a cured layer in which the charge transport material is dispersed in the curable resin. . The protective layer may be a layer in which a charge transport material is dispersed in a binder resin.

  The thickness of the protective layer is preferably 1 μm or more and 20 μm or less, more preferably 2 μm or more and 10 μm or less.

  Furthermore, as a coating method used when providing this protective layer, a normal method such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, or a curtain coating method is used. be able to.

  As a solvent used for coating, ordinary organic solvents such as dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, toluene and the like can be used singly or as a mixture of two or more kinds, but a solvent in which the lower layer is hardly dissolved is used as much as possible. Is preferred.

  The photoreceptor of this embodiment may be used in an electrophotographic apparatus such as a laser beam printer that emits near-infrared light or visible light, a digital copying machine, an LED printer, or a laser facsimile. The photoreceptor of this embodiment may be used in combination with a one-component or two-component regular developer or reversal developer. In addition, the photoreceptor of the present embodiment can provide good characteristics with little occurrence of current leakage even in a contact charging method using a charging roller or a charging brush.

<Image forming apparatus>
Next, the image forming apparatus of this embodiment will be described.
FIG. 5 is a schematic configuration diagram illustrating an example of the image forming apparatus according to the present exemplary embodiment. An image forming apparatus 100 shown in FIG. 5 includes the drum-shaped (cylindrical) electrophotographic photosensitive member 7 of the present embodiment provided to be rotatable. Around the electrophotographic photoreceptor 7, along the movement direction of the outer peripheral surface of the electrophotographic photoreceptor 7, a charging device 8, an exposure device 10 (an example of an electrostatic latent image forming device), a developing device 11, and a transfer device 12. The cleaning device 13 and the charge eliminating device (erase device) 14 are arranged in this order.
In addition, it is good also as an aspect which does not have the static elimination apparatus 14 from a viewpoint of cost reduction.

・ Charging device (charging means)
The charging device 8 is a corona charging type charging device and charges the electrophotographic photoreceptor 7. The charging device 8 is connected to a power source 9. Examples of the charging device 8 include a non-contact type roller charger, a scorotron charger using corona discharge, and a corotron charger.

Further, for example, a well-known charger such as a contact charger using a conductive charging roller, a charging brush, a charging film, a charging rubber blade, a charging tube or the like may be used.
Here, FIG. 6 is a schematic configuration diagram showing an example of a contact charging type image forming apparatus using the electrophotographic photosensitive member of the present embodiment.
The contact charging member used in the image forming apparatus 101 is disposed so as to be in contact with the surface of the photoconductor, and applies a voltage directly to the photoconductor to charge the surface of the photoconductor to a predetermined potential. This contact charging member includes metals such as aluminum, iron and copper, conductive polymer materials such as polyacetylene, polypyrrole and polythiophene, polyurethane rubber, silicone rubber, epichlorohydrin rubber, ethylene propylene rubber, acrylic rubber, fluoro rubber, A material in which metal oxide particles such as carbon black, copper iodide, silver iodide, zinc sulfide, silicon carbide, and metal oxide are dispersed in an elastomer material such as styrene-butadiene rubber and butadiene rubber is used.

Examples of the metal oxide used for the contact charging member include Z ₂ O, SnO ₂ , TiO ₂ , In ₂ O ₃ , MoO ₃ , or a composite oxide thereof. Moreover, perchlorate may be included in the elastomer material to impart conductivity.

Furthermore, a coating layer may be provided on the surface of the contact charging member. As a material for forming this coating layer, N-alkoxymethylated nylon, cellulose resin, vinyl pyridine resin, phenol resin, polyurethane, polyvinyl butyral, melamine and the like are used alone or in combination.
Further, an emulsion resin material, for example, an acrylic resin emulsion, a polyester resin emulsion, a polyurethane, particularly an emulsion resin synthesized by soap-free emulsion polymerization may be used. In these resins, in order to further adjust the resistivity, conductive agent particles may be dispersed or an antioxidant may be contained. Further, the emulsion resin may contain a leveling agent or a surfactant.

Examples of the shape of the contact charging member include a roller type, a blade type, a belt type, and a brush type. The resistance of the contact charging member is desirably 10 ² Ωcm or more and 10 ¹² Ωcm or less, more desirably 10 ³ Ωcm or more and 10 ⁸ Ωcm or less. The voltage applied to the contact charging member may be applied in the form of direct current or direct current + alternating current.

・ Exposure device (electrostatic latent image forming means)
The exposure apparatus 10 exposes the charged electrophotographic photoreceptor 7 to form an electrostatic latent image on the surface of the electrophotographic photoreceptor 7. Examples of the exposure apparatus 10 include optical system devices that expose the surface of the electrophotographic photoreceptor 7 with light such as semiconductor laser light, LED light, and liquid crystal shutter light imagewise. The wavelength of the light source is preferably in the spectral sensitivity region of the electrophotographic photoreceptor 7. The wavelength of the semiconductor laser is preferably, for example, near infrared having an oscillation wavelength of around 780 nm, but is not limited to this wavelength, and a laser having an oscillation wavelength in the range of 600 nm or a blue laser having an oscillation wavelength of 400 nm to 450 nm. May also be used. Further, as the exposure apparatus 10, for example, a surface emitting laser light source of a multi-beam output type is also effective for color image formation.

・ Developer (Developer)
The developing device 11 develops the electrostatic latent image with a developer to form a toner image. The developer preferably contains toner particles having a volume average particle diameter of 3 μm or more and 9 μm or less obtained by a polymerization method. The developing device 11 includes, for example, a configuration in which a developing roll disposed in the developing region facing the electrophotographic photosensitive member 7 is provided in a container that stores a two-component developer composed of toner and carrier.

・ Transfer device (transfer means)
The transfer device 12 transfers the toner image formed on the surface of the electrophotographic photoreceptor 7 to a recording medium. Examples of the transfer device 12 include known transfer chargers such as a contact transfer charger using a belt, a roller, a film, a rubber blade, a scorotron transfer charger using a corona discharge, and a corotron transfer charger. Can be mentioned.

Cleaning device The cleaning device 13 removes toner remaining on the surface of the electrophotographic photosensitive member 7 after transfer. The cleaning device 13 preferably has a blade member that contacts the electrophotographic photoreceptor 7 at a linear pressure of 10 g / cm to 150 g / cm. The cleaning device 13 includes, for example, a housing, a cleaning blade, and a cleaning brush disposed on the downstream side of the cleaning blade in the rotation direction of the electrophotographic photosensitive member 7. In addition, for example, a solid lubricant is disposed in contact with the cleaning brush.

-Neutralizing Device The neutralizing device (erasing device) 14 irradiates the surface of the electrophotographic photosensitive member 7 after transferring the toner image with static eliminating light to neutralize the potential remaining on the surface of the electrophotographic photosensitive member. For example, the static eliminator 14 irradiates static electricity over the entire width in the axial direction of the electrophotographic photosensitive member 7, and determines the potential difference between the exposed portion and the non-exposed portion by the exposure device 10 generated on the surface of the electrophotographic photosensitive member 7. Remove. In addition, the aspect in which the static elimination apparatus 14 is not provided may be sufficient.

Fixing Device The image forming apparatuses 100 and 101 include a fixing device 15 that fixes the toner image on the recording medium after the transfer process. The fixing device is not particularly limited, and examples thereof include known fixing devices such as a heat roller fixing device and an oven fixing device.

Next, operations of the image forming apparatuses 100 and 101 according to the present embodiment will be described. First, the electrophotographic photosensitive member 7 rotates along the direction indicated by the arrow A and is negatively charged by the charging device 8. The electrophotographic photosensitive member 7 whose surface is negatively charged by the charging device 8 is exposed by the exposure device 10 to form an electrostatic latent image on the surface.
When the portion where the electrostatic latent image is formed on the electrophotographic photosensitive member 7 approaches the developing device 11, the developing device 11 attaches toner to the electrostatic latent image and forms a toner image.
When the electrophotographic photosensitive member 7 on which the toner image is formed further rotates in the direction of arrow A, the toner image is transferred onto the recording paper P by the transfer device 12. As a result, a toner image is formed on the recording paper P.
The toner image is fixed on the recording paper P on which the image is formed by the fixing device 15.

<Process cartridge>
For example, the image forming apparatus according to the present embodiment may be configured such that a process cartridge including the electrophotographic photosensitive member 7 according to the present embodiment described above is attached to and detached from the image forming apparatus.
The configuration of the process cartridge according to the present embodiment only needs to include at least the electrophotographic photosensitive member 7 according to the present embodiment. In addition to the electrophotographic photosensitive member 7, for example, a charging device 8, an exposure device 10, and the like. You may provide the at least 1 component selected from the image development apparatus 11, the transfer apparatus 12, the cleaning apparatus 13, and the static elimination apparatus 14. FIG.
In the process cartridge of this embodiment, the charging device 8 may be a contact charging type charging unit.

  In addition, the image forming apparatus according to the present embodiment is not limited to the above-described configuration, and a known configuration, for example, an intermediate for transferring a toner image formed on the electrophotographic photosensitive member 7 to the intermediate transfer member and then transferring the toner image to the recording paper P. A transfer type image forming apparatus may be employed, or a tandem type image forming apparatus may be employed.

Hereinafter, although an Example and a comparative example are given and this embodiment is described in detail in detail, this embodiment is not limited to the following examples. Examples 1, 5 and 8 are reference examples.

(Surface treatment example 1)
100 parts by mass of zinc oxide (trade name: MZ-300 manufactured by Teika Co., Ltd.), 0.5 parts by mass of vinyltrimethoxysilane (KBM-1003 manufactured by Shin-Etsu Silicone Co., Ltd.) as a silane coupling agent and 200 parts by mass of toluene are mixed and stirred. And refluxed for 2 hours. Thereafter, toluene was distilled off under reduced pressure at 10 mmHg, followed by baking at 135 ° C. for 2 hours.

(Surface treatment example 2)
100 parts by mass of zinc oxide (trade name: MZ-300 manufactured by Teika Co., Ltd.), 0.5 parts by mass of 3-acryloxypropyltrimethoxysilane (KBM-5103 manufactured by Shin-Etsu Silicone) as a silane coupling agent, 200 parts by mass of toluene Were mixed and stirred, and refluxed for 2 hours. Thereafter, toluene was distilled off under reduced pressure at 10 mmHg, followed by baking at 135 ° C. for 2 hours.

(Surface treatment examples 3 to 6)
The treatment was performed in the same manner as in Surface Treatment Example 1 except that the metal oxide particles and the coupling agent shown in Table 1 were used.

[Example 1]
Zinc oxide (Taika Co., Ltd., MZ-300 No surface treatment): 33 parts by mass and blocked isocyanate Sumijoule 3175 (manufactured by Sumitomo Bayern Urethane Co., Ltd.): 6 parts by mass, methyl ethyl ketone: 25 parts by mass were mixed for 30 minutes, and then butyral resin BM-1 (manufactured by Sekisui Chemical Co., Ltd.): 5 parts by mass is added and dispersed for 3 hours with a sand mill. After the dispersion is completed, silicone ball tospar 130 (manufactured by Toshiba Silicone): 3 parts by mass is added and dispersed. A liquid was obtained. Further, this coating solution was applied onto an aluminum substrate having a diameter of 84 mm, a length of 340 mm, and a thickness of 1 mm by a dip coating method, followed by drying and curing at 180 ° C. for 30 minutes to obtain an intermediate layer having a thickness of 20 μm.
Thereafter, 170 parts by mass of n-butyl alcohol in which 4 parts by mass of polyvinyl butyral resin (Surek BM-S manufactured by Sekisui Chemical Co., Ltd.) was dissolved, 30 parts by mass of an organic zirconium compound (acetylacetone zirconium butyrate) and an organic silane compound (3-aminopropyl) 3 parts by mass of trimethoxysilane) was additionally mixed and stirred to obtain a coating solution. Further, this coating solution was applied onto the intermediate layer by a dip coating method, followed by drying and curing at 130 ° C. for 10 minutes to obtain an undercoat layer having a thickness of 1 μm.
Next, hydroxygallium phthalocyanine is used as a charge generation material, from 15 parts by mass thereof, from 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. The resulting mixture was dispersed in a sand mill for 4 hours. The obtained dispersion was dip-coated on the undercoat layer and dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.2 μm.
Furthermore, 4 parts by mass of N, N′-diphenyl-N, N′-bis (3-methylphenyl) -1,1′-biphenyl-4,4′-diamine and 6 parts by mass of bisphenol Z polycarbonate resin (molecular weight 40,000) A coating solution in which 25 parts by mass of tetrahydrofuran and 5 parts by mass of chlorobenzene were dissolved was applied onto the charge generation layer and dried at 130 ° C. for 40 minutes to form a charge transport layer having a thickness of 37 μm. A photoreceptor was obtained.

  The photoconductor obtained as described above is mounted on a copying machine DCC500 manufactured by Fuji Xerox Co., Ltd., and residual potential, black spot, ghost under high temperature and high humidity (30 ° C., 80% RH), high temperature after printing 100,000 sheets. Residual potential, black spots, and ghosts under wet conditions (30 ° C., 80% RH) were evaluated. The evaluation results are shown in Table 3. When the residual potential under high temperature and high humidity (30 ° C., 80% RH) after printing 100,000 sheets is -100 V or more (-100 V or more and 0 V or less), it is determined that there is no problem with respect to the life of the photoreceptor.

-Residual potential evaluation-
With the photoconductor rotated at 100 rpm, the photoconductor was charged to −700 V with a scorotron charger, and irradiated with light of 2.0 mJ / m ² using a semiconductor laser with a wavelength of 780 nm 0.05 seconds after charging. Was discharged. Subsequently, the photoconductor 0.1 seconds after discharging was irradiated with 20 mJ / m ² of red LED light to carry out slow charging. Then, the surface potential V of the photosensitive member 100 msec after slow current was measured, and this was used as the value of the residual potential.
Residual potential was evaluated according to the following criteria.
A: −50V or more B: −50V or less −100V or more C: −100V or less

-Ghost evaluation-
In the ghost evaluation, the chart shown in FIG. 7 is output continuously 100,000 sheets by A4 horizontal feed, and the first output image (initial image) and the image after 100,000 output (image after 100,000 sheets output) are visually observed. Were evaluated according to the following criteria.
The chart shown in FIG. 7 is a chart in which an area having a white “G” character and a halftone image area having an image density of 40% are printed in a black solid image having an image density of 100%.
The evaluation criteria are as follows.
A: No occurrence B: Some occurrence (no problem in actual use)
C: Occurrence (cannot be used)

−Spot evaluation−
The black spot evaluation was performed by visually observing and judging the degree of the dot-like image quality defect in the white background using the same sample as the ghost evaluation described above.
A: No black spot occurs.
B: Some black spots are generated.
C: There is a black spot that causes a problem in image quality.

[Example 2]
Zinc oxide (manufactured by Teika MZ-300, no surface treatment): 33 parts by mass and blocked isocyanate Sumidur 3175 (manufactured by Sumitomo Bayern Urethane): 6 parts by mass, 1 part of the above-described reactive acceptor material (1-6) Part, methyl ethyl ketone: 25 parts by mass are mixed for 30 minutes, but after that butyral resin BM-1 (manufactured by Sekisui Chemical Co., Ltd.): 5 parts by mass is added and dispersed for 3 hours with a sand mill. 130 (manufactured by Toshiba Silicone): 3 parts by mass was added to obtain a dispersion. Furthermore, this coating solution was applied on an aluminum substrate having a diameter of 84 mm, a length of 340 mm, and a thickness of 1 mm by a dip coating method, followed by drying and curing at 180 ° C. for 30 minutes to obtain an intermediate layer having a thickness of 20 μm. Were produced in the same manner as in Example 1 and evaluated in the same manner. The results are shown in Table 3.

[Examples 3 to 6]
A photoconductor was prepared in the same manner as in Example 2 except that the metal oxide surface-treated in Surface Treatment Examples 1 to 4 was used, and the same evaluation was performed. The results are shown in Table 3.

[Example 7]
In Example 3, a photoreceptor was prepared in the same manner as in Example 3 except that the reactive acceptor material (1-9) was used instead of the reactive acceptor material (1-6), and the same evaluation was performed. . The results are shown in Table 3.

[Example 8]
A photoconductor was prepared in the same manner as in Example 3 except that the reactive acceptor material (1-21) was used instead of the reactive acceptor material (1-6), and the same evaluation was performed. . The results are shown in Table 3.

[Comparative Example 1]
A photoconductor was prepared in the same manner as in Example 1 except that no undercoat layer was provided in Example 1, and the same evaluation was performed. The results are shown in Table 3.

[Comparative Example 2]
A photoconductor was prepared in the same manner as in Comparative Example 1 except that the metal oxide particles surface-treated in Surface Treatment Example 1 were used, and the same evaluation was performed. The results are shown in Table 3.

[Comparative Example 3]
A photoreceptor was prepared in the same manner as in Comparative Example 1 except that the metal oxide particles surface-treated in Surface Treatment Example 5 were used, and the same evaluation was performed. The results are shown in Table 3.

[Comparative Example 4]
In Example 3, a photoreceptor was prepared in the same manner as in Example 3 except that the undercoat layer was not provided, and the same evaluation was performed. The results are shown in Table 3.

[Comparative Example 5]
A photoconductor was produced in the same manner as in Comparative Example 1 except that the metal oxide particles surface-treated in Surface Treatment Example 6 were used, and the same evaluation was performed. The results are shown in Table 3.

  Table 2 summarizes the intermediate layer and the undercoat layer according to each example and comparative example.

  According to this embodiment, a photoconductor having excellent electrical characteristics and good image quality can be obtained. In addition, a long-life photoconductor that suppresses the generation of ghosts can be obtained even when used repeatedly.

DESCRIPTION OF SYMBOLS 1 Conductive substrate, 3 Photosensitive layer, 5 Protective layer, 7 Electrophotographic photosensitive member, 8 Charging device, 9 Power supply, 10 Exposure device, 11 Developing device, 12 Transfer device, 13 Cleaning device, 14 Static elimination device, 15 Fixing device, 21 intermediate layer, 22 undercoat layer, 31 charge generation layer, 32 charge transport layer, 100, 101 image forming apparatus

Claims (7)

A conductive substrate having a surface comprising aluminum;
An intermediate layer formed on the surface of the conductive substrate containing aluminum, containing tin oxide particles or zinc oxide particles and a binder resin as metal oxide particles, and an amine content of 0.1% by mass or less;
An undercoat layer formed on the intermediate layer and containing an organometallic compound having an amino group;
A photosensitive layer formed on the undercoat layer;
Have
An electrophotographic photoreceptor in which the intermediate layer contains an anthraquinone derivative represented by the following general formula (1).

(In the general formula (1), n1 is 2 or 3, n2 is .m 1 represents 0 represents 0 or 1, m @ 2 0 Table to .R ¹ and ^{R 2} are each independently carbon number Represents an alkoxy group of 1 or more and 10 or less, provided that when n1 is 2, m1 represents 1, and when n1 is 3, m1 represents 0.   The electrophotographic photosensitive member according to claim 1, wherein the metal oxide particles are surface-treated with a silane coupling agent having no amino group.   The electrophotographic photosensitive member according to claim 1, wherein the volume average particle diameter of the metal oxide particles is 10 nm or more and 100 nm or less. The electrophotographic photosensitive member according to any one of claims 1 to 3,
A process cartridge attached to and detached from the image forming apparatus.   The process cartridge according to claim 4, further comprising a contact charging type charging unit that charges the surface of the electrophotographic photosensitive member. The electrophotographic photosensitive member according to any one of claims 1 to 3,
Charging means for charging the surface of the electrophotographic photosensitive member;
An electrostatic 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 image forming apparatus according to claim 6, wherein the charging unit is a contact charging type charging unit.