JP2017062423A - Electrophotographic photoreceptor, process cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor that suppresses the occurrence of an afterimage phenomenon (ghost) occurring when image formation is repeated and the history of a previous image remains.SOLUTION: There is provided an electrophotographic photoreceptor comprising: a conductive substrate 1; an undercoat layer 2 that is arranged on the conductive substrate and contains an electron accepting compound represented by the following general formula (A) and a resin; and a photosensitive layer 3 that is arranged on the undercoat layer. In the general formula (A), Xand Xeach independently represent an oxygen atom or =C(CN); R, R, R, R, R, R, and Reach independently represent a hydrogen atom, a halogen atom, or an alkyl group; Rrepresents an alkylene group having 4 to 20 carbon atoms, inclusive.SELECTED DRAWING: Figure 1

Description

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

  Patent Document 1 discloses an electrophotographic photosensitive member having a photosensitive layer through an intermediate layer on a conductive support, wherein the intermediate layer contains a polyamide resin having a specific unit component. The body is disclosed.

  In Patent Document 2, in an image forming apparatus that forms an image by transferring a toner image formed on a photoconductor to a recording medium, the photoconductor is formed around a conductive base material and the conductive base material. The intermediate layer and a photosensitive layer formed around the intermediate layer, wherein the intermediate layer contains metal oxide fine particles having an average particle size of 100 nm or less in a binder resin. An image forming apparatus is disclosed.

  In Patent Document 3, in an electrophotographic photosensitive member in which a photoconductive layer is provided on a conductive substrate, a white pigment and a binder resin are main components between the conductive substrate and the photoconductive layer, and the white pigment and An intermediate layer having a binder resin usage ratio in the range of 1/1 to 3/1 by volume ratio was provided, and an undercoat layer was formed between the conductive substrate and the intermediate layer. An electrophotographic photosensitive member is disclosed.

Patent Document 4 discloses an electrophotographic photosensitive member comprising a conductive substrate, an intermediate layer formed on the substrate, and a photosensitive layer formed on the intermediate layer, wherein the intermediate layer is a metal oxide. And a volume resistance of 10 ⁸ to 10 ¹³ Ω · cm when an electric field of 10 ⁶ V / m is applied at 28 ° C. and 85% RH, and 15 ° C. and 15% RH The volume resistance when an electric field of 10 ⁶ V / m is applied at 28 ° C. and 85% RH is 500 times or less of the volume resistance when an electric field of 10 ⁶ V / m is applied. A photoreceptor is disclosed.

  Patent Document 5 includes an electrophotographic photosensitive member, a charging unit, an exposing unit, a developing unit, and a transferring unit, and an image that is charged, exposed, developed, and transferred while moving the outer peripheral surface of the electrophotographic photosensitive member in a predetermined direction. The forming apparatus further comprises control means for controlling the moving speed of the outer peripheral surface of the electrophotographic photosensitive member so that the time required from charging to development is variable, and the electrophotographic photosensitive member is at least an undercoat layer And an photosensitive layer, and the undercoat layer contains at least a metal oxide fine particle and an acceptor compound having a group capable of reacting with the metal oxide fine particle. .

  In Patent Document 6, in an electrophotographic photosensitive member in which a photosensitive layer having a charge generation layer and a charge transfer layer is provided on a conductive support, a modification having a specific repeating structural unit as a binder resin of the charge transfer layer. An electrophotographic photosensitive member containing a polycarbonate resin as a main component is disclosed.

  Patent Document 7 discloses an electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the surface layer contains a fluorine-based block polymer.

  Non-Patent Document 1 and Non-Patent Document 2 disclose photoreceptors using a high molecular weight binder resin, a charge transport material, an inorganic filler, and other additives.

Japanese Patent Laid-Open No. 5-11483 JP 2002-123028 A Japanese Patent Laid-Open No. 5-80572 JP 2003-186219 A JP 2006-30698 A JP-A-63-148263 JP-A-63-249152

Reducing environmental impact by improving the durability of photoconductors and developers: Konica Minolta Technology Report Vol. 6 pp. 17-22 (2009) Technology for extending the life of OPC photoreceptors: Journal of the Imaging Society of Japan, Vol. 47 117-123 (2008)

  In the present invention, the undercoat layer includes, as an electron-accepting compound, only an electron-accepting compound represented by the formula (1-1), (1-2), or (1-14) described later, An object of the present invention is to provide an electrophotographic photosensitive member in which occurrence of an afterimage phenomenon (ghost) caused by a history of a previous image remaining when image formation is repeated is suppressed.

In order to achieve the above object, the following invention is provided.
The invention according to claim 1
A conductive substrate;
An undercoat layer disposed on the conductive substrate and containing an electron-accepting compound represented by the following general formula (A) and a resin;
A photosensitive layer disposed on the undercoat layer;
An electrophotographic photosensitive member having:

In general formula (A), X ¹ and X ² each independently represent an oxygen atom or ═C (CN) ₂ , and R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ are each Independently represents a hydrogen atom, a halogen atom, or an alkyl group, and R ⁸ represents an alkylene group having 4 to 20 carbon atoms.

The invention according to claim 2
The undercoat layer contains metal oxide particles and contains 1 to 5 parts by mass of the electron-accepting compound represented by the general formula (A) with respect to 100 parts by mass of the metal oxide particles. The electrophotographic photosensitive member according to claim 1.

The invention according to claim 3
The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer has a charge generation layer and a charge transport layer, and the outermost surface layer of the electrophotographic photosensitive member contains a fluororesin.

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

The invention according to claim 5
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 a developer containing toner to form a toner image;
Transfer means for transferring the toner image to the surface of the recording medium;
An image forming apparatus comprising:

  According to the first aspect of the present invention, the electron-accepting compound includes only the electron-accepting compound represented by the formula (1-1), (1-2) or (1-14) described later. An electrophotographic photosensitive member is provided in which ghosting is suppressed when image formation is repeated.

  According to the invention of claim 2, the undercoat layer contains metal oxide particles, and the electron-accepting compound represented by the general formula (A) with respect to 100 parts by mass of the metal oxide particles. An electrophotographic photosensitive member is provided in which the occurrence of ghost is suppressed when image formation is repeated as compared with the case where the content is less than 1 part by mass.

  According to the invention of claim 3, the photosensitive layer has a charge generation layer and a charge transport layer, and the outermost surface layer of the electrophotographic photosensitive member does not contain a fluororesin. A photographic photoreceptor is provided.

  According to the invention which concerns on Claim 4 or Claim 5, an undercoat layer is an electron represented by the formula (1-1), (1-2) or (1-14) mentioned later as an electron-accepting compound. There is provided a process cartridge or an image forming apparatus in which the occurrence of ghost is suppressed when image formation is repeated as compared with a case where an electrophotographic photoreceptor containing only a receptive compound is provided.

It is the schematic which shows an example of the layer structure of the electrophotographic photoreceptor which concerns on this embodiment. It is the schematic which shows the other example of the layer structure of the electrophotographic photoreceptor which concerns on this embodiment. It is the schematic which shows the other example of the layer structure of the electrophotographic photoreceptor which concerns on this embodiment. It is the schematic which shows the other example of the layer structure of the electrophotographic photoreceptor which concerns on this embodiment. It is the schematic which shows the other example of the layer structure of the electrophotographic photoreceptor which concerns on this embodiment. It is the schematic which shows the other example of the layer structure of the electrophotographic photoreceptor which concerns on this embodiment. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment. It is a schematic block diagram which shows the other example of the image forming apparatus which concerns on this embodiment. In an Example, it is a figure which shows the chart used for image quality evaluation.

  Hereinafter, the electrophotographic photoreceptor according to the exemplary embodiment will be described in detail with reference to the drawings. Note that the reference numerals are omitted.

[Electrophotographic photoreceptor]
An electrophotographic photoreceptor according to the exemplary embodiment (hereinafter sometimes referred to as “photoreceptor”) is disposed on the conductive substrate, and includes an electron-accepting compound and a resin represented by the following general formula (A). An undercoat layer containing the photosensitive layer, and a photosensitive layer disposed on the undercoat layer.

In general formula (A), X ¹ and X ² each independently represent an oxygen atom or ═C (CN) ₂ , and R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ are each Independently represents a hydrogen atom, a halogen atom, or an alkyl group, and R ⁸ represents an alkylene group having 4 to 20 carbon atoms.

By using the electrophotographic photosensitive member according to the present embodiment, the occurrence of an afterimage phenomenon (ghost) caused by the history of the previous image remaining when image formation is repeated is suppressed. The reason is considered as follows.
An electrophotographic photoreceptor often reaches the end of its life after repeated use due to an increase in the residual potential of the undercoat layer, resulting in image quality anomalies such as ghosts and fog (a phenomenon in which toner adheres to non-image areas).
In conventional electrophotographic photoreceptors, for example, an anthraquinone electron-accepting compound such as alizarin is used to suppress an increase in the residual potential of the undercoat layer. On the other hand, the electron-accepting compound represented by the general formula (A) has a higher charge transport ability than the anthraquinone-based electron-accepting compound, and the electrophotographic photoreceptor according to this embodiment has an undercoat layer represented by the general formula (A It is considered that the increase in residual potential is effectively suppressed, and the occurrence of ghost is suppressed even when image formation is repeated.

1 to 6 are schematic views showing examples of the layer structure of the photoreceptor according to the present embodiment. The photoreceptor shown in FIG. 1 includes a conductive substrate 1, an undercoat layer 2 formed on the conductive substrate 1, and a single layer type (functional integrated type) formed on the undercoat layer 2. Photosensitive layer 3. The single-layer type photosensitive layer 3 includes, for example, a resin, a charge generation material, and a charge transport material.
As shown in FIG. 2, the photosensitive layer 3 may be a laminated type (function separation type) photosensitive layer in which a charge generation layer 31 and a charge transport layer 32 are laminated. The charge generation layer 31 includes, for example, a resin and a charge generation material, and the charge transport layer 32 includes, for example, a resin and a charge transport material.

  Furthermore, the electrophotographic photosensitive member according to the present embodiment may be provided with a protective layer 5 on the photosensitive layer 3 or the charge transport layer 32 as shown in FIGS. 5 and 6, an intermediate layer 4 may be provided between the undercoat layer 2 and the photosensitive layer 3 or between the undercoat layer 2 and the charge generation layer 31.

  In addition, although the intermediate | middle layer 4 has shown the aspect provided between the undercoat layer 2 and the photosensitive layer 3, or between the undercoat layer 2 and the electric charge generation layer 31, the electroconductive base material 1 and an undercoat layer are shown. 2 may be provided. Of course, the aspect which does not provide the intermediate | middle layer 4 may be sufficient.

  Next, each element of the electrophotographic photosensitive member according to this embodiment will be described. Note that the reference numerals are omitted. As a representative example, an electrophotographic photoreceptor provided with a laminated photosensitive layer will be mainly described.

(Conductive substrate)
Examples of the conductive substrate include metal plates (eg, aluminum, copper, zinc, chromium, nickel, molybdenum, vanadium, indium, gold, platinum, etc.) or alloys (stainless steel, etc.), metal drums, metal belts, etc. Is mentioned. In addition, as the conductive substrate, for example, paper, resin film, belt, etc. coated, vapor-deposited or laminated with a conductive compound (for example, conductive polymer, indium oxide, etc.), metal (for example, aluminum, palladium, gold, etc.) or an alloy, etc. Also mentioned. Here, “conductive” means that the volume resistivity is less than 10 ¹³ Ωcm.

  When the electrophotographic photosensitive member is used in a laser printer, the surface of the conductive substrate has a center line average roughness Ra of 0.04 μm or more and 0.5 μm for the purpose of suppressing interference fringes generated when laser light is irradiated. The surface is preferably roughened below. When non-interfering light is used as a light source, roughening for preventing interference fringes is not particularly required, but it is suitable for extending the life because it suppresses generation of defects due to irregularities on the surface of the conductive substrate.

  As a roughening method, for example, wet honing performed by suspending an abrasive in water and spraying it on a support, centerless grinding in which a conductive substrate is pressed against a rotating grindstone, and grinding is continuously performed, Anodizing treatment etc. are mentioned.

  As a roughening method, without roughening the surface of the conductive substrate, conductive or semiconductive powder is dispersed in the resin to form a layer on the surface of the conductive substrate. The method of roughening by the particle | grains disperse | distributed in a layer is also mentioned.

  In the roughening treatment by anodic oxidation, a metal (for example, aluminum) conductive substrate is used as an anode, and an oxide film is formed on the surface of the conductive substrate by anodizing in an electrolyte solution. Examples of the electrolyte solution include a sulfuric acid solution and an oxalic acid solution. However, the porous anodic oxide film formed by anodic oxidation is chemically active as it is, easily contaminated, and has a large resistance fluctuation due to the environment. Therefore, the pores of the oxide film are blocked by the volume expansion due to the hydration reaction in pressurized water vapor or boiling water (a metal salt such as nickel may be added) against the porous anodic oxide film, and more stable hydration oxidation It is preferable to perform a sealing treatment for changing to a product.

  The thickness of the anodized film is preferably, for example, 0.3 μm or more and 15 μm or less. When this film thickness is within the above range, the barrier property against implantation tends to be exhibited, and the increase in residual potential due to repeated use tends to be suppressed.

The conductive substrate may be treated with an acidic treatment liquid or boehmite treatment.
The treatment with the acidic treatment liquid is performed as follows, for example. First, an acidic treatment liquid containing phosphoric acid, chromic acid and hydrofluoric acid is prepared. The mixing ratio of phosphoric acid, chromic acid and hydrofluoric acid in the acidic treatment liquid is, for example, in the range of 10% by mass to 11% by mass of phosphoric acid, in the range of 3% by mass to 5% by mass of chromic acid, The concentration of these acids is preferably in the range of 13.5% by mass or more and 18% by mass or less. The treatment temperature is preferably 42 ° C. or higher and 48 ° C. or lower, for example. The film thickness is preferably from 0.3 μm to 15 μm.

  The boehmite treatment is performed, for example, by immersing in pure water of 90 ° C. or higher and 100 ° C. or lower for 5 minutes to 60 minutes, or by contacting with heated steam of 90 ° C. or higher and 120 ° C. or lower for 5 minutes to 60 minutes. The film thickness is preferably 0.1 μm or more and 5 μm or less. This may be further anodized using an electrolyte solution with low film solubility such as adipic acid, boric acid, borate, phosphate, phthalate, maleate, benzoate, tartrate, citrate, etc. Good.

(Undercoat layer)
The undercoat layer in the present embodiment contains an electron-accepting compound represented by the following general formula (A) (hereinafter sometimes referred to as “first electron-accepting compound”) and a resin, It contains inorganic particles such as metal oxide particles, organic particles such as silicone resin particles, and the like.

In general formula (A), X ¹ and X ² each independently represent an oxygen atom or ═C (CN) ₂ , and R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ are each Independently represents a hydrogen atom, a halogen atom, or an alkyl group, and R ⁸ represents an alkylene group having 4 to 20 carbon atoms.

In general formula (A), X ¹ and X ² are preferably ═C (CN) _{2 from} the viewpoint of electron transport ability.

In the general formula (A), examples of the halogen atom represented by R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. It is done. Among these, a fluorine atom or a chlorine atom is preferable, and a chlorine atom is more preferable.

The functional group substituted for R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ may be selected in consideration of solubility in the resin, crystal precipitation, electron transport ability, and the like. . For example, when a halogen atom (a chlorine atom, a fluorine atom, or the like) is substituted, the electron transport ability is easily improved. Further, for example, when an alkyl group is substituted, crystal precipitation is easily suppressed, and further, solubility with a resin having an aromatic ring such as a polycarbonate resin is easily improved.

In the general formula (A), examples of the alkyl group represented by R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ are linear or branched and have 1 to 20 carbon atoms. The following alkyl groups are mentioned. Examples of the linear alkyl group include a methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, and n-nonyl. Group, n-decyl group and the like.
Examples of the branched alkyl group include isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, isopentyl group, neopentyl group, tert-pentyl group, isohexyl group, sec-hexyl group, tert-hexyl group, Isoheptyl group, sec-heptyl group, tert-heptyl group, isooctyl group, sec-octyl group, tert-octyl group, isononyl group, sec-nonyl group, tert-nonyl group, isodecyl group, sec-decyl group, tert-decyl Groups and the like. Among these, the carbon number of the alkyl group is more preferably 1 or more and 4 or less, and further preferably 1 or more and 3 or less.

In the general formula (A), examples of the alkylene group having 4 to 20 carbon atoms represented by R ⁸ include a linear or branched alkylene group. For example, n-butylene group, isobutylene group, sec-butylene group, tert-butylene group, n-pentylene group, isopentylene group, neopentylene group, tert-pentylene group, n-hexylene, n-peptylene, n-octylene, n- Nonylene group, n-decylene group, n-undecylene group, n-dodecylene group and the like can be mentioned. In addition, a tridecylene group, a tetradecylene group, a pentadecylene group, a hexadecylene group, an octadecylene group, an eicosylene group, and the like can be given. Among these, from the viewpoint of solubility with a resin, a linear or branched alkylene group having 6 to 12 carbon atoms is preferable.

  Although an exemplary compound is shown below about the electron-accepting compound (1st electron-accepting compound) represented by general formula (A), it is not necessarily limited to these. In addition, the following exemplary compound numbers are described as an exemplary compound (A-number) below. Specifically, for example, (A-15) is represented below as “Exemplary Compound (A-15)”.

  Abbreviations in the above exemplified compounds have the following meanings. “Bu” represents a butyl group, “t-Bu” represents a tert-butyl group, “Cl” represents a chlorine atom, and “Me” represents a methyl group.

The content of the first electron-accepting compound in the undercoat layer is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and further preferably 1% by mass or more from the viewpoint of suppressing the occurrence of ghost. preferable. On the other hand, from the viewpoint of forming a conductive path, the content of the first electron-accepting compound in the undercoat layer is preferably 25% by mass or less, and more preferably 20% by mass or less.
In addition, the 1st electron-accepting compound in an undercoat layer may be contained individually by 1 type, and 2 or more types may be contained. When 2 or more types of 1st electron-accepting compounds are contained, it is preferable that total content is the said range.

  The undercoat layer in the present embodiment contains at least the electron accepting compound (first electron accepting compound) represented by the general formula (A) as the electron accepting compound, and is represented by the general formula (A). An electron-accepting compound other than the electron-accepting compound (hereinafter sometimes referred to as “second electron-accepting compound”) may be contained.

As the second electron-accepting compound, an electron-accepting compound having an acidic group is preferably used. Examples of the acidic group include a hydroxyl group (phenolic hydroxyl group), a carboxyl group, and a sulfonyl group.
Specific examples of the second electron-accepting compound include quinone, anthraquinone, coumarin, phthalocyanine, triphenylmethane, anthocyanin, flavone, fullerene, ruthenium complex, xanthene, benzoxazine, porphyrin. Compounds of the system.
In particular, the second electron-accepting compound is preferably an anthraquinone-based material (anthraquinone derivative) in consideration of suppressing the density unevenness of the halftone image and considering the safety, availability, and electron transport capability of the material. Although it is a compound represented by General formula (1), it is desirable. An anthraquinone derivative means a compound having an anthraquinone skeleton.
Among these, among the compounds represented by the general formula (1), a compound in which R ¹¹ and R ¹² each independently represents an alkoxy group having 1 to 10 carbon atoms is preferable.

In general formula (1), n1 and n2 each independently represent an integer of 0 or more and 3 or less. However, at least one of n1 and n2 independently represents an integer of 1 or more and 3 or less (that is, n1 and n2 do not simultaneously represent 0). m1 and m2 each independently represent an integer of 0 or 1. R ¹¹ and R ¹² each independently represents an alkyl group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms.

  The second electron-accepting compound may be a compound represented by the following general formula (2).

In general formula (2), n1, n2, n3, and n4 each independently represent an integer of 0 or more and 3 or less. m1 and m2 each independently represent an integer of 0 or 1. At least one of n1 and n2 independently represents an integer of 1 or more and 3 or less (that is, n1 and n2 do not simultaneously represent 0). At least one of n3 and n4 each independently represents an integer of 1 or more and 3 or less (that is, n3 and n4 do not simultaneously represent 0). r represents an integer of 2 or more and 10 or less. R ¹¹ and R ¹² 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 ¹¹ and R ¹² may be 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 ¹¹ and R ¹² may be either 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 alkoxyl group having 1 to 8 carbon atoms, more preferably an alkoxyl group having 1 to 6 carbon atoms.

  Specific examples of the second electron-accepting compound are shown below, but are not limited thereto.

Examples of the inorganic particles include inorganic particles having a powder resistance (volume resistivity) of 10 ² Ωcm or more and 10 ¹¹ Ωcm or less.
Among these, as the inorganic particles having the resistance value, for example, metal oxide particles such as tin oxide particles, titanium oxide particles, zinc oxide particles, and zirconium oxide particles are preferable, and zinc oxide particles are particularly preferable.

The specific surface area of the inorganic particles by the BET method is preferably 10 m ² / g or more, for example.
The volume average particle diameter of the inorganic particles is, for example, preferably from 50 nm to 2000 nm (preferably from 60 nm to 1000 nm).

  For example, the content of the inorganic particles is preferably 10% by mass or more and 80% by mass or less, and more preferably 40% by mass or more and 80% by mass or less with respect to the resin.

  The inorganic particles may be subjected to a surface treatment. Two or more inorganic particles having different surface treatments or particles having different particle diameters may be mixed and used.

  Examples of the surface treatment agent include a silane coupling agent, a titanate coupling agent, an aluminum coupling agent, and a surfactant. In particular, a silane coupling agent is preferable, and an amino group-containing silane coupling agent is more preferable.

  Examples of the silane coupling agent having an amino group include 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, and N-2- (aminoethyl) -3-amino. Examples include, but are not limited to, propylmethyldimethoxysilane, N, N-bis (2-hydroxyethyl) -3-aminopropyltriethoxysilane, and the like.

  Two or more silane coupling agents may be used in combination. For example, a silane coupling agent having an amino group and another silane coupling agent may be used in combination. Other silane coupling agents include, for example, vinyltrimethoxysilane, 3-methacryloxypropyl-tris (2-methoxyethoxy) silane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycol. Sidoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- ( Aminoethyl) -3-aminopropylmethyldimethoxysilane, N, N-bis (2-hydroxyethyl) -3-aminopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, and the like, but are not limited thereto. It is not a thing.

  The surface treatment method using the surface treatment agent may be any method as long as it is a known method, and may be either a dry method or a wet method.

  The treatment amount of the surface treatment agent is preferably 0.5% by mass or more and 10% by mass or less with respect to the inorganic particles, for example.

  Here, the undercoat layer contains the electron-accepting compound (first electron-accepting compound and, if necessary, the second electron-accepting compound) together with the inorganic particles. It is good from the viewpoint of improving the nature.

  The electron-accepting compound may be dispersed and included in the undercoat layer together with the inorganic particles, or may be included in a state of being attached to the surface of the inorganic particles.

  Examples of the method for attaching the electron accepting compound to the surface of the inorganic particles include a dry method and a wet method.

  In the dry method, for example, while stirring inorganic particles with a mixer having a large shearing force or the like, an electron-accepting compound dissolved directly or in an organic solvent is dropped and sprayed with dry air or nitrogen gas. It is a method of adhering to the surface of inorganic particles. When the electron-accepting compound is dropped or sprayed, it is preferably performed at a temperature not higher than the boiling point of the solvent. After dropping or spraying the electron-accepting compound, baking may be performed at 100 ° C. or higher. The baking is not particularly limited as long as it is a temperature and time for obtaining electrophotographic characteristics.

  In the wet method, for example, an electron-accepting compound is added while dispersing inorganic particles in a solvent by stirring, ultrasonic waves, a sand mill, an attritor, a ball mill, etc., and after stirring or dispersing, the solvent is removed to remove electrons. This is a method of attaching a receptive compound to the surface of inorganic particles. The solvent removal method is distilled off by filtration or distillation, for example. After removing the solvent, baking may be performed at 100 ° C. or higher. The baking is not particularly limited as long as it is a temperature and time for obtaining electrophotographic characteristics. In the wet method, the water content of the inorganic particles may be removed before adding the electron-accepting compound. Examples thereof include a method of removing while stirring and heating in a solvent, and a method of removing by azeotropic distillation with a solvent. Can be mentioned.

  The attachment of the electron-accepting compound may be performed before or after the surface treatment with the surface treatment agent is performed on the inorganic particles, or may be performed simultaneously with the attachment of the electron-accepting compound and the surface treatment with the surface treatment agent.

  When the undercoat layer contains metal oxide particles, the total content of electron-accepting compounds (the total content of the first electron-accepting compound and the second electron-accepting compound when they are included) is a chemical reaction Alternatively, it is determined from the surface area and content of the metal oxide particles to be adsorbed and the electron transport ability of each material, but it is usually in the range of 0.01% by mass or more and 20% by mass or less. It is the range of 1 mass% or more and 10 mass% or less. When the content of the electron accepting compound is 0.1% by mass or more, the effect of the electron accepting compound is easily exhibited. Further, when the content of the electron-accepting compound is 20% by mass or less, aggregation of the metal oxide particles is suppressed, and the distribution of the metal oxide particles tends to be uniform in the undercoat layer, and a good conductive path is obtained. Easy to form. Therefore, the increase in residual potential is suppressed, and the occurrence of ghost is effectively suppressed.

  Moreover, from a viewpoint of suppressing generation | occurrence | production of a ghost more effectively, 1 mass part of electron-accepting compounds (1st electron-accepting compound) represented by general formula (A) with respect to 100 mass parts of metal oxide particles are used. The content is preferably 5 parts by mass or less, more preferably 1.5 parts by mass or more and 4.5 parts by mass or less. When the undercoat layer contains two or more kinds of first electron-accepting compounds, the total content of the two or more kinds of first electron-accepting compounds with respect to 100 parts by mass of the metal oxide particles may be in the above range. preferable.

Examples of the resin used for the undercoat layer include acetal resins (eg, polyvinyl butyral), polyvinyl alcohol resins, polyvinyl acetal resins, casein resins, polyamide resins, cellulose resins, gelatin, polyurethane resins, polyester resins, unsaturated polyester resins, Methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, urea resin, phenol resin, phenol-formaldehyde resin, melamine resin, urethane resin , Known polymer compounds such as alkyd resins and epoxy resins; zirconium chelate compounds; titanium chelate compounds; aluminum chelate compounds; titanium alkoxide compounds; Machine titanium compound; known materials such as a silane coupling agent.
Examples of the resin used for the undercoat layer include a charge transporting resin having a charge transporting group and a conductive resin (for example, polyaniline).

Among these, as the resin used for the undercoat layer, a resin insoluble in the upper layer coating solvent is suitable, and in particular, a urea resin, a phenol resin, a phenol-formaldehyde resin, a melamine resin, a urethane resin, an unsaturated polyester resin, Thermosetting resins such as alkyd resins and epoxy resins; at least one resin selected from the group consisting of polyamide resins, polyester resins, polyether resins, methacrylic resins, acrylic resins, polyvinyl alcohol resins and polyvinyl acetal resins and a curing agent Resins obtained by reaction with are preferred.
When two or more of these resins are used in combination, the mixing ratio is set as necessary.

The undercoat layer may contain various additives for improving electrical characteristics, improving environmental stability, and improving image quality.
Additives include known materials such as 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, and silane coupling agents. It is done. The silane coupling agent is used for the surface treatment of the inorganic particles as described above, but may be further added to the undercoat layer as an additive.

  Examples of the silane coupling agent as the additive include vinyltrimethoxysilane, 3-methacryloxypropyl-tris (2-methoxyethoxy) silane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3- Glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (Aminoethyl) -3-aminopropylmethylmethoxysilane, N, N-bis (2-hydroxyethyl) -3-aminopropyltriethoxysilane, 3-chloropropyltrimethoxysilane and the like can be mentioned.

  Examples of the zirconium chelate compound include zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate 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.

  Examples of the titanium chelate compound include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, and titanium lactate ammonium salt. , Titanium lactate, titanium lactate ethyl ester, titanium triethanolamate, polyhydroxy titanium stearate and the like.

  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 additives may be used alone or as a mixture or polycondensate of a plurality of compounds.

The undercoat layer preferably has a Vickers hardness of 35 or more.
The surface roughness (ten-point average roughness) of the undercoat layer is from 1 / (4n) (n is the refractive index of the upper layer) of the exposure laser wavelength λ used to suppress the moire image (1/2). ) It is preferable that the adjustment is made up to λ.
Resin particles or the like may be added to the undercoat layer for adjusting the surface roughness. Examples of the resin particles include silicone resin particles and cross-linked polymethyl methacrylate resin particles. Further, the surface of the undercoat layer may be polished for adjusting the surface roughness. Examples of the polishing method include buffing, sandblasting, wet honing, and grinding.

  There is no particular limitation on the formation of the undercoat layer, and a well-known formation method is used. For example, a coating film for forming an undercoat layer in which the above components are added to a solvent is formed, and the coating film is dried. And heating as necessary.

Solvents for preparing the coating solution for forming the undercoat layer include known organic solvents such as alcohol solvents, aromatic hydrocarbon solvents, halogenated hydrocarbon solvents, ketone solvents, ketone alcohol solvents, ether solvents. Examples include solvents and ester solvents.
Specific examples of these solvents include methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, Examples include ordinary organic solvents such as n-butyl acetate, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, and toluene.

  Examples of the dispersion method of the inorganic particles when preparing the coating liquid for forming the undercoat layer include known methods such as a roll mill, a ball mill, a vibration ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker.

  Examples of the method for applying the coating liquid for forming the undercoat layer onto the conductive substrate include, for example, 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. The usual methods such as these are mentioned.

  The thickness of the undercoat layer is, for example, preferably set in the range of 15 μm or more, more preferably 20 μm or more and 50 μm or less.

(Middle layer)
Although illustration is omitted, an intermediate layer may be further provided between the undercoat layer and the photosensitive layer.
An intermediate | middle layer is a layer containing resin, for example. Examples of the resin used for the intermediate layer include an acetal resin (for example, polyvinyl butyral), polyvinyl alcohol resin, polyvinyl acetal resin, casein resin, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, Polymer compounds such as polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, melamine resin, and the like can be given.
The intermediate layer may be a layer containing an organometallic compound. Examples of the organometallic compound used for the intermediate layer include organometallic compounds containing metal atoms such as zirconium, titanium, aluminum, manganese, and silicon.
The compounds used for these intermediate layers may be used alone or as a mixture or polycondensate of a plurality of compounds.

  Among these, the intermediate layer is preferably a layer containing an organometallic compound containing a zirconium atom or a silicon atom.

The formation of the intermediate layer is not particularly limited, and a well-known formation method is used. For example, a coating film of an intermediate layer forming coating solution in which the above components are added to a solvent is formed, and the coating film is dried and necessary. It is performed by heating according to.
As the coating method for forming the intermediate layer, usual methods such as 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, and a curtain coating method are used.

  For example, the thickness of the intermediate layer is preferably set in a range of 0.1 μm to 3 μm. An intermediate layer may be used as the undercoat layer.

(Charge generation layer)
The charge generation layer is, for example, a layer containing a charge generation material and a resin. The charge generation layer may be a vapor deposition layer of a charge generation material. The vapor-deposited layer of the charge generation material is suitable when an incoherent light source such as an LED (Light Emitting Diode) or an organic EL (Electro-Luminescence) image array is used.

  Examples of the charge generating material include azo pigments such as bisazo and trisazo; fused aromatic pigments such as dibromoanthanthrone; perylene pigments; pyrrolopyrrole pigments; phthalocyanine pigments; zinc oxide;

  Among these, in order to cope with near-infrared laser exposure, it is preferable to use a metal phthalocyanine pigment or a metal-free phthalocyanine pigment as the charge generation material. Specifically, for example, hydroxygallium phthalocyanine disclosed in JP-A-5-263007, JP-A-5-279591, etc .; chlorogallium phthalocyanine disclosed in JP-A-5-98181; More preferred are dichlorotin phthalocyanines disclosed in JP-A No. 140472, JP-A No. 5-140473 and the like; and titanyl phthalocyanine disclosed in JP-A No. 4-189873.

  On the other hand, in order to cope with laser exposure in the near-ultraviolet region, as the charge generation material, condensed aromatic pigments such as dibromoanthanthrone; thioindigo pigments; porphyrazine compounds; zinc oxide; trigonal selenium; Bisazo pigments and the like disclosed in 2004-78147 and JP-A-2005-181992 are preferred.

  The above-described charge generation material may also be used in the case of using an incoherent light source such as an LED having a central wavelength of light emission of 450 nm to 780 nm and an organic EL image array. However, from the viewpoint of resolution, the photosensitive layer is 20 μm or less. When the thin film is used, the electric field strength in the photosensitive layer is increased, and a charge decrease due to charge injection from the substrate, that is, an image defect called a black spot is likely to occur. This becomes conspicuous when a charge generating material that easily generates a dark current is used in a p-type semiconductor such as trigonal selenium or a phthalocyanine pigment.

On the other hand, when an n-type semiconductor such as a condensed ring aromatic pigment, perylene pigment, azo pigment or the like is used as the charge generation material, dark current hardly occurs and even a thin film can suppress image defects called black spots. . Examples of the n-type charge generation material include compounds (CG-1) to (CG-27) described in paragraphs [0288] to [0291] of JP2012-155282A. It is not limited.
The n-type determination is performed by using a time-of-flight method that is usually used, and is determined by the polarity of the flowing photocurrent, and an n-type is more likely to flow electrons as carriers than holes.

The resin used for the charge generation layer is selected from a wide range of insulating resins, and the resin may be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, polyvinylpyrene, and polysilane. Good.
Examples of the resin include polyvinyl butyral resin, polyarylate resin (polycondensate of bisphenols and aromatic divalent carboxylic acid, etc.), polycarbonate resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyamide resin. , Acrylic resin, polyacrylamide resin, polyvinyl pyridine resin, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol resin, polyvinyl pyrrolidone resin, and the like. Here, “insulating” means that the volume resistivity is 10 ¹³ Ωcm or more.
These resins are used alone or in combination of two or more.

  The mixing ratio of the charge generation material and the resin is preferably in the range of 10: 1 to 1:10 by mass ratio.

  In addition, the charge generation layer may contain a known additive.

  The formation of the charge generation layer is not particularly limited, and a known formation method is used. For example, a coating film of a charge generation layer forming coating solution in which the above components are added to a solvent is formed, and the coating film is dried. And heating as necessary. The charge generation layer may be formed by vapor deposition of a charge generation material. Formation of the charge generation layer by vapor deposition is particularly suitable when a condensed ring aromatic pigment or perylene pigment is used as the charge generation material.

  Solvents for preparing the charge generation layer forming coating solution include methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-acetate. -Butyl, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, toluene and the like. These solvents are used alone or in combination of two or more.

Examples of a method for dispersing particles (for example, a charge generation material) in a coating solution for forming a charge generation 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 stirring, an ultrasonic disperser, etc. Medialess dispersers such as roll mills and high-pressure homogenizers are used. Examples of the high-pressure homogenizer include a collision method in which a dispersion liquid is dispersed by liquid-liquid collision or liquid-wall collision in a high pressure state, and a penetration method in which a fine flow path is dispersed in a high pressure state.
In this dispersion, it is effective that the average particle size of the charge generation material in the coating solution for forming the charge generation layer is 0.5 μm or less, preferably 0.3 μm or less, more preferably 0.15 μm or less. .

  Examples of methods for applying the charge generation layer forming coating solution on the undercoat layer (or on the intermediate layer) include blade coating, wire bar coating, spray coating, dip coating, bead coating, and air knife coating. And usual methods such as a curtain coating method.

  The film thickness of the charge generation layer is, for example, preferably set in the range of 0.1 μm to 5.0 μm, more preferably 0.2 μm to 2.0 μm.

(Charge transport layer)
The charge transport layer is, for example, a layer containing a charge transport material and a resin. The charge transport layer may be a layer containing a polymer charge transport material.

  Examples of charge transport materials include quinone compounds such as p-benzoquinone, chloranil, bromanyl and anthraquinone; tetracyanoquinodimethane compounds; fluorenone compounds such as 2,4,7-trinitrofluorenone; xanthone compounds; benzophenone compounds A cyanovinyl compound; an electron transporting compound such as an ethylene compound; Examples of the charge transporting material include hole transporting compounds such as triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted ethylene compounds, stilbene compounds, anthracene compounds, and hydrazone compounds. These charge transport materials may be used alone or in combination of two or more, but are not limited thereto.

  As the charge transport material, from the viewpoint of charge mobility, a triarylamine derivative represented by the following structural formula (a-1) and a benzidine derivative represented by the following structural formula (a-2) are preferable.

In Structural Formula (a-1), Ar ^T1 , Ar ^T2 , and Ar ^T3 are each independently a substituted or unsubstituted aryl group, —C ₆ H ₄ —C (R ^T4 ) ═C (R ^T5 ) (R ^T6), or _{-C 6 H 4 -CH = CH-} CH = C (R T7) shows the ^{(R T8).} R ^T4 , R ^T5 , R ^T6 , R ^T7 , and R ^T8 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group.
Examples of the substituent for each group include a halogen atom, an alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms. Examples of the substituent of each group also include a substituted amino group substituted with an alkyl group having 1 to 3 carbon atoms.

In Structural Formula (a-2), R ^T91 and R ^T92 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 ^T101 , R ^T102 , R ^T111 and R ^T112 are each independently ^substituted with 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. A substituted amino group, a substituted or unsubstituted aryl group, —C (R ^T12 ) ═C (R ^T13 ) (R ^T14 ), or —CH═CH— ^CH═C (R ^T15 ) (R ^T16 ), R ^T12 , R ^T13 , R ^T14 , R ^T15 and R ^T16 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. Tm1, Tm2, Tn1, and Tn2 each independently represent an integer of 0 or more and 2 or less.
Examples of the substituent for each group include a halogen atom, an alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms. Examples of the substituent of each group also include a substituted amino group substituted with an alkyl group having 1 to 3 carbon atoms.

Here, among the triarylamine derivative represented by the structural formula (a-1) and the benzidine derivative represented by the structural formula (a-2), in particular, “—C ₆ H ₄ —CH═CH—CH═ Triarylamine derivatives having “C (R ^T7 ) (R ^T8 )” and benzidine derivatives having “—CH═CH— ^CH═C (R ^T15 ) (R ^T16 )” are preferable from the viewpoint of charge mobility.

  As the polymer charge transporting material, known materials having charge transporting properties such as poly-N-vinylcarbazole and polysilane are used. In particular, polyester-based polymer charge transport materials disclosed in JP-A-8-176293, JP-A-8-208820 and the like are particularly preferable. The polymeric charge transport material may be used alone or in combination with a resin.

The resin used for the charge transport layer is polycarbonate resin, polyester resin, polyarylate 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-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N-vinyl Examples thereof include carbazole and polysilane. Among these, polycarbonate resin or polyarylate resin is suitable as the resin. These resins are used alone or in combination of two or more.
The mixing ratio of the charge transport material and the resin is preferably 10: 1 to 1: 5 by mass ratio.

  In addition, the charge transport layer may contain a known additive.

  The formation of the charge transport layer is not particularly limited, and a well-known formation method is used. This is done by heating as necessary.

  Solvents for preparing the coating solution for forming the charge transport layer include aromatic hydrocarbons such as benzene, toluene, xylene and chlorobenzene; ketones such as acetone and 2-butanone; methylene chloride, chloroform and ethylene chloride. Halogenated aliphatic hydrocarbons: Usual organic solvents such as cyclic or linear ethers such as tetrahydrofuran and ethyl ether. These solvents are used alone or in combination of two or more.

  Coating methods for applying the charge transport layer forming coating solution on the charge generation layer include blade coating method, wire bar coating method, spray coating method, dip coating method, bead coating method, air knife coating method, curtain A usual method such as a coating method may be mentioned.

  The film thickness of the charge transport layer is, for example, preferably set in the range of 5 μm to 50 μm, more preferably 10 μm to 30 μm.

(Protective layer)
The protective layer is provided on the photosensitive layer as necessary. The protective layer is provided, for example, for the purpose of preventing chemical change of the photosensitive layer during charging or further improving the mechanical strength of the photosensitive layer.
Therefore, it is preferable to apply a layer composed of a cured film (crosslinked film) as the protective layer. Examples of these layers include the layers shown in 1) or 2) below.

1) A layer composed of a cured film of a composition containing a reactive group-containing charge transporting material having a reactive group and a charge transporting skeleton in the same molecule (that is, a polymer or cross-linking of the reactive group-containing charge transporting material) Layer containing body)
2) a layer composed of a cured film of a composition comprising a non-reactive charge transport material and a reactive group-containing non-charge transport material having a reactive group and having no charge transport skeleton (that is, A layer comprising a non-reactive charge transport material and a polymer or a cross-linked product of the reactive group-containing non-charge transport material)

The reactive group of the reactive group-containing charge transport material includes a chain polymerizable group, an epoxy group, —OH, —OR [wherein R represents an alkyl group], —NH ₂ , —SH, —COOH, —SiR. ^Q1 _3-Qn (OR ^Q2 ) _Qn [wherein R ^Q1 represents a hydrogen atom, an alkyl group, or a substituted or unsubstituted aryl group, and R ^Q2 represents a hydrogen atom, an alkyl group, or a trialkylsilyl group. Qn represents an integer of 1 to 3], and the like, and other well-known reactive groups.

  The chain polymerizable group is not particularly limited as long as it is a functional group capable of radical polymerization. For example, it is a functional group having a group containing at least a carbon double bond. Specific examples include a group containing at least one selected from a vinyl group, a vinyl ether group, a vinyl thioether group, a vinyl phenyl group, a styryl group, an acryloyl group, a methacryloyl group, and derivatives thereof. Among these, because of its excellent reactivity, the chain polymerizable group is a group containing at least one selected from a vinyl group, a vinylphenyl group, a styryl group, an acryloyl group, a methacryloyl group, and derivatives thereof. Preferably there is.

  The charge transporting skeleton of the reactive group-containing charge transporting material is not particularly limited as long as it is a known structure in an electrophotographic photoreceptor, and examples thereof include triarylamine compounds, benzidine compounds, hydrazone compounds, and the like. And a structure conjugated from a nitrogen-containing hole transporting compound and conjugated with a nitrogen atom. Among these, a triarylamine skeleton is preferable.

  The reactive group-containing charge transport material having a reactive group and a charge transport skeleton, a non-reactive charge transport material, and a reactive group-containing non-charge transport material may be selected from well-known materials.

  In addition, the protective layer may contain known additives.

  The formation of the protective layer is not particularly limited, and a well-known forming method is used. It is performed by performing a curing process such as heating as necessary.

Solvents for preparing the coating solution for forming the protective layer include aromatic solvents such as toluene and xylene; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ester solvents such as ethyl acetate and butyl acetate; tetrahydrofuran And ether solvents such as dioxane; cellosolv solvents such as ethylene glycol monomethyl ether; alcohol solvents such as isopropyl alcohol and butanol. These solvents are used alone or in combination of two or more.
The protective layer forming coating solution may be a solventless coating solution.

  As a method for applying the coating solution for forming the protective layer on the photosensitive layer (for example, charge transport layer), dip coating method, push-up coating method, wire bar coating method, spray coating method, blade coating method, knife coating method, curtain coating method. Ordinary methods such as a method may be mentioned.

  The thickness of the protective layer is, for example, preferably set in the range of 1 μm to 20 μm, more preferably 2 μm to 10 μm.

Regardless of the presence or absence of the protective layer, it is preferable that the outermost surface layer contains a fluororesin from the viewpoint of suppressing the surface abrasion and extending the life.
Examples of the fluororesin that can be included in the outermost surface layer include, for example, a tetrafluoroethylene resin, a trifluorinated ethylene chloride resin, a difluorinated dichloroethylene resin, a hexafluoroethylene propylene resin, a vinyl fluoride resin, and a vinylidene fluoride resin. , And copolymers thereof. These fluorine-containing resin particles may be used alone or in combination of two or more.

  The average particle size of the fluorine-containing resin particles is preferably 100 nm or more and 1000 nm or less, and the content of the fluorine-containing resin particles is 5% by mass or more and 15% by mass or less with respect to the outermost surface layer. desirable. The average primary particle diameter of the fluorine-containing resin particles is a value observed and measured by SEM (scanning electron microscope), and is an average value measured for 25 randomly selected fluorine-containing resin particles.

(Single layer type photosensitive layer)
The single-layer type photosensitive layer (charge generation / charge transport layer) is, for example, a layer containing a charge generation material, a charge transport material, and, if necessary, a resin and other well-known additives. Note that these materials are the same as those described for the charge generation layer and the charge transport layer.
In the single-layer type photosensitive layer, the content of the charge generating material is preferably 10% by mass or more and 85% by mass or less, and preferably 20% by mass or more and 50% by mass or less with respect to the total solid content. In the single-layer type photosensitive layer, the content of the charge transport material is preferably 5% by mass or more and 50% by mass or less based on the total solid content.
The method for forming the single-layer type photosensitive layer is the same as the method for forming the charge generation layer and the charge transport layer.
The film thickness of the single-layer type photosensitive layer is, for example, from 5 μm to 50 μm, and preferably from 10 μm to 40 μm.

[Image forming apparatus (and process cartridge)]
The image forming apparatus according to the present embodiment includes an electrophotographic photosensitive member, a charging unit that charges the surface of the electrophotographic photosensitive member, and an electrostatic latent image formation that forms an electrostatic latent image on the surface of the charged electrophotographic photosensitive member. Means, developing means for developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive member with a developer containing toner to form a toner image, and transfer means for transferring the toner image to the surface of the recording medium; Is provided. The electrophotographic photosensitive member according to the present embodiment is applied as the electrophotographic photosensitive member.

  The image forming apparatus according to the present embodiment includes an apparatus having fixing means for fixing a toner image transferred to the surface of a recording medium; direct transfer for directly transferring the toner image formed on the surface of the electrophotographic photosensitive member to the recording medium Type apparatus; intermediate transfer in which the toner image formed on the surface of the electrophotographic photosensitive member is primarily transferred onto the surface of the intermediate transfer member, and the toner image transferred onto the surface of the intermediate transfer member is secondarily transferred onto the surface of the recording medium. Type of apparatus; apparatus with cleaning means for cleaning the surface of the electrophotographic photosensitive member after the toner image is transferred and before charging; after the toner image is transferred, the surface of the electrophotographic photosensitive member is irradiated with a charge eliminating light before charging. A known image forming apparatus such as an apparatus provided with an electrophotographic photoreceptor heating member for raising the temperature of the electrophotographic photoreceptor and reducing the relative temperature is applied.

  In the case of an intermediate transfer type apparatus, the transfer means includes, for example, an intermediate transfer body on which a toner image is transferred to the surface, and a primary transfer that primarily transfers the toner image formed on the surface of the electrophotographic photosensitive member to the surface of the intermediate transfer body. A configuration including a transfer unit and a secondary transfer unit that secondarily transfers the toner image transferred onto the surface of the intermediate transfer member onto the surface of the recording medium is applied.

  The image forming apparatus according to the present embodiment may be either a dry developing type image forming apparatus or a wet developing type (developing type using a liquid developer).

  Note that in the image forming apparatus according to the present embodiment, for example, the portion including the electrophotographic photosensitive member may have a cartridge structure (process cartridge) that is detachable from the image forming apparatus. As the process cartridge, for example, a process cartridge including the electrophotographic photosensitive member according to this embodiment is preferably used. In addition to the electrophotographic photosensitive member, the process cartridge may include at least one selected from the group consisting of a charging unit, an electrostatic latent image forming unit, a developing unit, and a transfer unit.

  Hereinafter, an example of the image forming apparatus according to the present embodiment will be described, but the present invention is not limited thereto. In addition, the main part shown to a figure is demonstrated and the description is abbreviate | omitted about others.

FIG. 7 is a schematic configuration diagram illustrating an example of an image forming apparatus according to the present embodiment.
As shown in FIG. 7, the image forming apparatus 100 according to this embodiment includes a process cartridge 300 including an electrophotographic photosensitive member 7, an exposure device 9 (an example of an electrostatic latent image forming unit), and a transfer device 40 (primary. Transfer device) and an intermediate transfer member 50. In the image forming apparatus 100, the exposure device 9 is disposed at a position where the electrophotographic photosensitive member 7 can be exposed from the opening of the process cartridge 300, and the transfer device 40 is interposed between the electrophotographic photosensitive member via the intermediate transfer member 50. 7, and a part of the intermediate transfer member 50 is disposed in contact with the electrophotographic photosensitive member 7. Although not shown, it also has a secondary transfer device that transfers the toner image transferred to the intermediate transfer member 50 to a recording medium (for example, paper). The intermediate transfer member 50, the transfer device 40 (primary transfer device), and the secondary transfer device (not shown) correspond to an example of a transfer unit.

  In the process cartridge 300 in FIG. 7, an electrophotographic photosensitive member 7, a charging device 8 (an example of a charging unit), a developing device 11 (an example of a developing unit), and a cleaning device 13 (an example of a cleaning unit) are integrated in a housing. I support it. The cleaning device 13 includes a cleaning blade (an example of a cleaning member) 131, and the cleaning blade 131 is disposed so as to contact the surface of the electrophotographic photosensitive member 7. The cleaning member may be a conductive or insulating fibrous member instead of the cleaning blade 131, and may be used alone or in combination with the cleaning blade 131.

  In FIG. 7, as an image forming apparatus, a fibrous member 132 (roll shape) for supplying the lubricant 14 to the surface of the electrophotographic photosensitive member 7 and a fibrous member 133 (flat brush shape) for assisting cleaning are shown. Examples are provided, but these are arranged as necessary.

  Hereinafter, each configuration of the image forming apparatus according to the present embodiment will be described.

-Charging device-
As the charging device 8, for example, a contact type charger using a conductive or semiconductive charging roller, a charging brush, a charging film, a charging rubber blade, a charging tube or the like is used. Further, a non-contact type roller charger, a known charger such as a scorotron charger using a corona discharge or a corotron charger may be used.

-Exposure device-
Examples of the exposure device 9 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 in a predetermined image-like manner. The wavelength of the light source is set within the spectral sensitivity region of the electrophotographic photosensitive member. As the wavelength of the semiconductor laser, near infrared having an oscillation wavelength near 780 nm is the mainstream. However, the present invention is not limited to this wavelength, and an oscillation wavelength laser in the 600 nm range or a laser having an oscillation wavelength of 400 nm to 450 nm as a blue laser may be used. In addition, a surface-emitting type laser light source that can output a multi-beam is also effective for color image formation.

-Developer-
Examples of the developing device 11 include a general developing device that performs development by bringing a developer into contact or non-contact with the developer. The developing device 11 is not particularly limited as long as it has the functions described above, and is selected according to the purpose. For example, a known developing device having a function of attaching a one-component developer or a two-component developer to the electrophotographic photosensitive member 7 using a brush, a roller, or the like can be used. Among these, those using a developing roller holding the developer on the surface are preferable.

  The developer used in the developing device 11 may be a one-component developer including a toner alone or a two-component developer including a toner and a carrier. Further, the developer may be magnetic or non-magnetic. A well-known thing is applied for these developers.

-Cleaning device-
As the cleaning device 13, a cleaning blade type device including a cleaning blade 131 is used.
In addition to the cleaning blade method, a fur brush cleaning method and a simultaneous development cleaning method may be employed.

-Transfer device-
As the transfer device 40, for example, a contact transfer charger using a belt, a roller, a film, a rubber blade, etc., or a known transfer charger such as a scorotron transfer charger using a corona discharge or a corotron transfer charger. Can be mentioned.

-Intermediate transfer member-
As the intermediate transfer member 50, a belt-like member (intermediate transfer belt) containing polyimide, polyamideimide, polycarbonate, polyarylate, polyester, rubber or the like having semiconductivity is used. Further, as the form of the intermediate transfer member, a drum-like one may be used in addition to the belt-like.

FIG. 8 is a schematic configuration diagram illustrating another example of the image forming apparatus according to the present embodiment.
An image forming apparatus 120 shown in FIG. 8 is a tandem multicolor image forming apparatus equipped with four process cartridges 300. In the image forming apparatus 120, four process cartridges 300 are arranged in parallel on the intermediate transfer member 50, and one electrophotographic photosensitive member is used for one color. The image forming apparatus 120 has the same configuration as that of the image forming apparatus 100 except that it is a tandem system.

  Hereinafter, although an embodiment explains this embodiment in detail, this embodiment is not limited to these examples at all. In the following description, “part” and “%” are all based on mass unless otherwise specified.

[Surface treatment example 1]
100 parts by mass of zinc oxide (trade name: MZ-300 manufactured by Teika Co., Ltd.), 10 parts by mass of a 10% by weight toluene solution of 3-aminopropyltriethoxysilane 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.

[Example 1]
<Production of electrophotographic photoreceptor>
(Formation of undercoat layer)
Zinc oxide surface-treated in surface treatment example 1: 33 parts by mass, blocked isocyanate (Sumijoule 3175, manufactured by Sumitomo Bayern Urethane Co., Ltd.): 6 parts by mass, represented by the following formula (AI) as the first electron-accepting compound The electron-accepting compound (corresponding to the exemplified compound (A-7)): 0.7 parts by mass and methyl ethyl ketone: 25 parts by mass were mixed for 30 minutes.

Then, butyral resin (ESREC BM-1, manufactured by Sekisui Chemical Co., Ltd.): 5 parts by mass, silicone resin particles (Tospearl 120, manufactured by Momentive Performance Materials): 3 parts by mass, leveling agent (silicone oil SH29PA, Toray Dow Corning Silicone Co., Ltd.): 0.01 part by mass was added, and dispersion was performed for 2 hours with a sand mill to obtain a dispersion.
Further, this dispersion was applied onto the aluminum substrate 1 by a dip coating method, followed by drying and curing at 180 ° C. for 30 minutes to obtain an undercoat layer having a thickness of 20 μm.

(Formation of charge generation layer)
Next, 15 parts by mass of hydroxygallium phthalocyanine is used as a charge generation material, 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 mixture consisting of 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.

(Formation of charge transport layer)
Furthermore, 200 parts by mass of N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1 ′] biphenyl-4,4′-diamine and bisphenol Z polycarbonate resin (molecular weight 40,000) 280 After dissolving 2000 parts by mass of tetrahydrofuran with 2000 parts by mass of tetrahydrofuran, 50 parts by mass of tetrafluoroethylene resin (manufactured by Daikin Industries, Ltd .: Lubron L5 average particle size 300 nm), 15 parts by mass of silica particles (manufactured by Nippon Aerosil Co., Ltd .: R104) And 1 part by mass of a fluorine-based comb polymer (manufactured by Toa Gosei Co., Ltd .: GF400) were added and dispersed at 5000 rpm for 3 hours using a homogenizer (manufactured by IKA: Ultra Tarrax) to prepare a coating solution. The obtained coating solution was applied onto the charge generation layer and dried at 130 ° C. for 30 minutes to form a charge transport layer having a thickness of 25 μm.
Thereby, the photoreceptor 1 of Example 1 was obtained.

[Evaluation]
The photoreceptor obtained as described above was mounted on a Fuji Xerox Copier DocuCentre C5570, and a halftone image of 35% density shown in FIG. 9 was formed to evaluate the occurrence of ghost and fog. One million images were output, and the initial (first image) and millionth images were evaluated.

-Ghost evaluation-
After forming the halftone image shown in FIG. 9 as an image for ghost evaluation under the conditions of 10 ° C. and 15% humidity, the entire halftone image is printed in the next cycle, and the ghost is raised on the halftone image. Images were evaluated based on the following criteria. The results are shown in Table 1.
G1: No occurrence G2: Very slight occurrence G3: Minor occurrence No problem in actual use G4: Minor occurrence. There is a problem in actual use G5: Occurrence

-Fog evaluation-
An image was output under conditions of a temperature of 20 ° C. and a humidity of 25%, and the degree of fogging was visually evaluated according to the following criteria. The results are shown in Table 1.
G1: No occurrence G2: Very slight occurrence G3: Minor occurrence No problem in actual use G4: Minor occurrence. There is a problem in actual use G5: Occurrence

[Examples 2 to 3]
In the formation of the undercoat layer in Example 1, in place of 0.7 part by mass of the electron-accepting compound represented by the formula (AI), the addition amount shown in Table 1 is represented by the formula (AI). A photoconductor was prepared and evaluated in the same manner as in Example 1 except that the electron accepting compound and the second electron accepting compound were used.

[Examples 4 to 6]
In the formation of the undercoat layer in Example 1, in place of 0.7 part by mass of the electron accepting compound represented by the formula (AI) as the first electron accepting compound, the following formula is used in the addition amount shown in Table 1. A photoconductor was prepared in the same manner as in Example 1 except that the electron accepting compound represented by (A-II) (corresponding to the exemplified compound (A-3)) and the second electron accepting compound were used. And evaluated.

[Comparative Examples 1 to 3]
In the formation of the undercoat layer in Example 1, in the same manner as in Example 1 except that the electron accepting compound shown in Table 1 was used instead of the electron accepting compound represented by the formula (AI). A photoconductor was prepared and evaluated.

[Examples 7 to 8]
In the formation of the undercoat layer in Example 1, in place of 0.7 part by mass of the electron-accepting compound represented by the formula (AI), the addition amount shown in Table 1 is used to represent the following formula (A-III). A photoreceptor was prepared and evaluated in the same manner as in Example 1 except that the electron-accepting compound (corresponding to the exemplified compound (A-31)) and the second electron-accepting compound were used.

[Examples 9 to 10]
In the formation of the undercoat layer in Example 1, instead of 0.7 part by mass of the electron-accepting compound represented by the formula (AI), the addition amount shown in Table 1 is used to represent the following formula (A-IV). A photoconductor was prepared and evaluated in the same manner as in Example 1 except that the electron-accepting compound (corresponding to the exemplified compound (A-12)) and the second electron-accepting compound were used.

From the above results, when an electrophotographic photosensitive member in which the undercoat layer contains an electron accepting compound (first electron accepting compound) represented by the general formula (A) is used, ghosting occurs when image formation is repeated. In particular, an electrophotographic photosensitive member (Examples 1, 2, 4, 5, 7 and 9) show that the occurrence of ghost is remarkably suppressed.
Further, in Example 3 and Example 6, the occurrence of fog after printing 1 million sheets is suppressed in Example 3 than in Example 6. This is presumably because the electron-withdrawing groups of the first electron-accepting compound are different.

DESCRIPTION OF SYMBOLS 1 Conductive base material, 2 Undercoat layer, 3 Photosensitive layer, 4 Intermediate layer, 5 Protective layer, 7 Electrophotographic photosensitive member, 8 Charging apparatus, 9 Exposure apparatus, 11 Developing apparatus, 13 Cleaning apparatus, 14 Lubricant, 31 Charge generation layer, 32 Charge transport layer, 40 Transfer device, 50 Intermediate transfer member, 100 Image forming device, 120 Image forming device, 300 Process cartridge

Claims (5)

A conductive substrate;
An undercoat layer disposed on the conductive substrate and containing an electron-accepting compound represented by the following general formula (A) and a resin;
A photosensitive layer disposed on the undercoat layer;
An electrophotographic photosensitive member having:


[In General Formula (A), X ¹ and X ² each independently represent an oxygen atom or ═C (CN) ₂ , and R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ are Each independently represents a hydrogen atom, a halogen atom, or an alkyl group, and R ⁸ represents an alkylene group having 4 to 20 carbon atoms. ]   The undercoat layer contains metal oxide particles and contains 1 to 5 parts by mass of the electron-accepting compound represented by the general formula (A) with respect to 100 parts by mass of the metal oxide particles. The electrophotographic photosensitive member according to claim 1.   The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer has a charge generation layer and a charge transport layer, and the outermost surface layer of the electrophotographic photosensitive member contains a fluororesin. The electrophotographic photosensitive member according to any one of claims 1 to 3,
A process cartridge that can be attached to and detached from an image forming apparatus. 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 a developer containing toner to form a toner image;
Transfer means for transferring the toner image to the surface of the recording medium;
An image forming apparatus comprising: