JP2012073281A - Electrophotographic photoreceptor, process cartridge and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor having excellent fast responsiveness and suppressing increase in a residual potential with lapse of time.SOLUTION: The electrophotographic photoreceptor includes a charge generating layer containing at least a charge generating material, a charge transporting layer containing a first charge transporting material, and a surface protective layer containing a second charge transporting material, in this order on a substrate, and satisfies the following expressions (1) to (3). They are (1):|Ip(CTL)-Ip(CGL)|≤0.1 (eV), (2):|Ip(OCL)-Ip(CTL)|≤0.3 (eV); and (3):μ(CTL)≥1.8×10[cm/Vs]. In expressions (1) to (3), Ip(CGL) represents an ionization potential of the charge generating material, Ip(CTL) represents an ionization potential of the first charge transporting material, Ip(OCL) represents an ionization potential of the second charge transporting material, and μ(CTL) represents a hole mobility of the charge transporting layer in an electric field intensity of 30 V/μm.

Description

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

  In recent years, so-called xerographic image forming apparatuses having charging means, exposure means, developing means, transfer means, and fixing means have further increased speed, improved image quality, and extended service life due to technological progress of each member and system. It is illustrated.

  In the electrophotographic photosensitive member, a resin having high mechanical strength is used, and a method of adding fluorine-containing resin particles to the surface protective layer has been proposed (for example, see Patent Document 1).

  In addition, there is a demand for a photoreceptor corresponding to a toner having a small particle diameter, and a method has been proposed in which the surface protective layer of the photoreceptor contains fluorine-containing resin particles to reduce the surface energy (for example, patents). Reference 2).

Japanese Patent Laid-Open No. 04-324451 JP 2008-46197 A

  An object of the present invention is to provide an electrophotographic photoreceptor excellent in high-speed response and suppressing an increase in residual potential over time as compared with a case where at least one of formulas (1) to (3) is not satisfied. is there.

The above problem is solved by the following means. That is,
The invention according to claim 1
On the substrate, a charge generation layer containing at least a charge generation material, a charge transport layer containing a first charge transport material, and a surface protective layer containing a second charge transport material in this order, The electrophotographic photosensitive member satisfies the following formulas (1) to (3).
Formula (1) | Ip (CTL) −Ip (CGL) | ≦ 0.1 (eV)
Formula (2) | Ip (OCL) −Ip (CTL) | ≦ 0.3 (eV)
Formula (3) μ (CTL) ≧ 1.8 × 10 ⁻⁵ [cm ² / Vs]
(In Formulas (1) to (3), Ip (CGL) is the ionization potential of the charge generation material, Ip (CTL) is the ionization potential of the first charge transport material, and Ip (OCL) is the first potential. (2) The ionization potential of the charge transport material 2 and μ (CTL) represents the hole mobility of the charge transport layer at an electric field strength of 30 V / μm.

The invention according to claim 2
The electrophotographic photoreceptor according to claim 1, wherein the formula (2) satisfies the following formula (2 ′), the formula (3) satisfies the following formula (3 ′), and further satisfies the following formula (4). .
Formula (2 ′) | Ip (OCL) −Ip (CTL) | ≦ 0.2 (eV)
Formula (3 ′) μ (CTL) ≧ 2.5 × 10 ⁻⁵ [cm ² / Vs]
Formula (4) 0.5 ≦ μ (CTL) / μ (OCL) ≦ 5
(In Formula (2 ′), Formula (3 ′) and Formula (4), Ip (CTL) is the ionization potential of the first charge transport material, and Ip (OCL) is the ionization potential of the second charge transport material. The potential, μ (CTL) represents the hole mobility of the charge transport layer at an electric field strength of 30 V / μm, and μ (OCL) represents the hole mobility of the surface protective layer at an electric field strength of 30 V / μm.)

The invention according to claim 3
The electrophotographic photosensitive member according to claim 1, wherein the first charge transport material is represented by the following (general formula 1) or (general formula 2).

(In the above (general formula 1), R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ , R ³⁶ may be the same or different and each represents a hydrogen atom, an alkyl group, an alkoxy group, a phenoxy group. Represents a halogen atom or an aryl group which may have a substituent, and m and n represent 0 or 1.)

(In the above (general formula 2), R ³⁷ , R ³⁸ , R ³⁹ , R ⁴⁰ , R ⁴¹ , R ⁴² , R ⁴³ may be the same or different, and each represents a hydrogen atom, an alkyl group, or an alkoxy group. , A phenoxy group, a halogen atom, or an aryl group which may have a substituent, m and n each represents 0 or 1)

The invention according to claim 4
The electrophotographic photosensitive member according to claim 1, wherein the surface protective layer contains a crosslinked product of a composition containing fluorine-based resin particles.

The invention according to claim 5
On the substrate, a charge generation layer containing at least a charge generation material, a charge transport layer containing a first charge transport material, and a surface protective layer containing a second charge transport material in this order, And an electrophotographic photoreceptor satisfying the following formulas (1) to (3):
And a charging device for charging the electrophotographic photosensitive member, a latent image forming device for forming an electrostatic latent image on the surface of the charged electrophotographic photosensitive member, and an electrostatic latent image formed on the surface of the electrophotographic photosensitive member. Select from a developing device that forms a toner image by developing with toner, a transfer device that transfers a toner image formed on the surface of the electrophotographic photosensitive member to a recording medium, and a cleaning device that cleans the surface of the electrophotographic photosensitive member A process cartridge having at least one of the above.
Formula (1) | Ip (CTL) −Ip (CGL) | ≦ 0.1 (eV)
Formula (2) | Ip (OCL) −Ip (CTL) | ≦ 0.3 (eV)
Formula (3) μ (CTL) ≧ 1.8 × 10 ⁻⁵ [cm ² / Vs]
(In Formulas (1) to (3), Ip (CGL) is the ionization potential of the charge generation material, Ip (CTL) is the ionization potential of the first charge transport material, and Ip (OCL) is the first potential. (2) The ionization potential of the charge transport material 2 and μ (CTL) represents the hole mobility of the charge transport layer at an electric field strength of 30 V / μm.
It is.

The invention according to claim 6
On the substrate, a charge generation layer containing at least a charge generation material, a charge transport layer containing a first charge transport material, and a surface protective layer containing a second charge transport material in this order, And an electrophotographic photosensitive member satisfying the following formulas (1) to (3):
A charging device for charging the electrophotographic photosensitive member,
A latent image forming apparatus for forming an electrostatic latent image on the surface of the charged electrophotographic photosensitive member;
A developing device for developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive member with toner to form a toner image;
And a transfer device for transferring a toner image formed on the surface of the electrophotographic photosensitive member to a recording medium,
An image forming apparatus.
Formula (1) | Ip (CTL) −Ip (CGL) | ≦ 0.1 (eV)
Formula (2) | Ip (OCL) −Ip (CTL) | ≦ 0.3 (eV)
Formula (3) μ (CTL) ≧ 1.8 × 10 ⁻⁵ [cm ² / Vs]
(In Formulas (1) to (3), Ip (CGL) is the ionization potential of the charge generation material, Ip (CTL) is the ionization potential of the first charge transport material, and Ip (OCL) is the first potential. (2) The ionization potential of the charge transport material 2 and μ (CTL) represents the hole mobility of the charge transport layer at an electric field strength of 30 V / μm.

The invention according to claim 7 provides:
The image forming apparatus according to claim 6, wherein the moving speed of the outer peripheral surface of the electrophotographic photosensitive member is 500 mm / s or more.

  According to the first aspect of the present invention, there is provided an electrophotographic photoreceptor excellent in high-speed response and suppressing an increase in residual potential over time as compared with a case where at least one of formulas (1) to (3) is not satisfied. Provided.

  According to the invention of claim 2, compared with the case where at least one of the expressions (2 ′), (3 ′), and (4) is not satisfied, the high-speed response is excellent and the residual potential increases with time. A suppressed electrophotographic photoreceptor is provided.

  According to the invention of claim 3, compared to the case where the charge transporting material does not satisfy the above (general formula 1) or (general formula 2), the electrophotography is excellent in high-speed response and suppresses the increase in residual potential over time. A photoreceptor is provided.

  According to the invention of claim 4, even when fluorine-containing resin particles are contained, the high-speed response is excellent and the time-lapse is superior to the case where at least one of the formulas (1) to (3) is not satisfied. An electrophotographic photosensitive member in which an increase in residual potential is suppressed is provided.

  According to the fifth aspect of the present invention, there is provided a process cartridge capable of forming an image excellent in high-speed response and excellent in image quality over a long period of time as compared with a case where at least one of the expressions (1) to (3) is not satisfied. Provided.

  According to the invention of claim 6, compared to a case where at least one of the formulas (1) to (3) is not satisfied, the electrophotographic photosensitive member capable of forming an image excellent in high-speed response and excellent in image quality over a long period of time. The body is provided.

  According to the invention of claim 7, even when the movement speed of the outer peripheral surface is as high as 500 mm / s or higher, compared with a case where at least one of formulas (1) to (3) is not satisfied, high-speed response is achieved. An electrophotographic photosensitive member capable of forming an image having excellent image quality over a long period of time is provided.

1 is a cross-sectional view illustrating an outline of an electrophotographic photoreceptor according to an exemplary embodiment. 1 is a schematic configuration diagram illustrating an image forming apparatus according to an exemplary embodiment. It is a schematic block diagram which shows the other image forming apparatus which concerns on this embodiment. It is a schematic block diagram which shows the other image forming apparatus which concerns on this embodiment. It is a figure which shows the evaluation pattern and evaluation criteria of a ghost.

  Hereinafter, embodiments of the present invention will be described in detail.

<Electrophotographic photoreceptor>
The electrophotographic photoreceptor according to the exemplary embodiment (hereinafter sometimes simply referred to as “photoreceptor”) has a charge generation layer containing at least a charge generation material and a charge containing a first charge transport material on a substrate. It has a transport layer and a surface protective layer containing a second charge transport material in this order, and satisfies the following formulas (1) to (3).
Formula (1) | Ip (CTL) −Ip (CGL) | ≦ 0.1 (eV)
Formula (2) | Ip (OCL) −Ip (CTL) | ≦ 0.3 (eV)
Formula (3) μ (CTL)> ≧ 1.8 × 10 ⁻⁵ [cm ² / Vs]
(In Formulas (1) to (3), Ip (CGL) is the ionization potential of the charge generation material, Ip (CTL) is the ionization potential of the first charge transport material, and Ip (OCL) is the first potential. (2) The ionization potential of the charge transport material 2 and μ (CTL) represents the hole mobility of the charge transport layer at an electric field strength of 30 V / μm.

First, a process in which the electrophotographic photosensitive member forms an electrostatic latent image in the image forming apparatus will be described. First, when the photosensitive member charged by the charging device is irradiated with writing light by the exposure device (latent image forming device), the charge generating material that has absorbed the light generates charge carriers, and the charge carriers are injected into the charge transport layer. Is done. Further, the charge carriers move in the charge transport layer due to the electric field generated by charging, and further, the charge carriers are also injected into the surface protective layer, transport in the surface protective layer according to the electric field, and reach the surface of the photoreceptor. Thus, the charge carrier and the charged charge are neutralized to form an electrostatic latent image.
At this time, the ionization potential affects the ease of charge injection between the respective layers (the charge generation layer and the charge transport layer, and the charge transport layer and the surface protective layer). The charge generation material and the first charge transport The difference in ionization potential with the material and the difference in ionization potential between the first charge transport material and the second charge transport material are not within appropriate ranges, that is, the above formulas (1) and (2) If not satisfied, charge carriers may be accumulated at the interface of each layer by repeating image formation over a long period of time, resulting in an increase in residual potential over time.
In addition, when the movement speed of the charge carriers moving in the charge transport layer is slow, that is, when the expression (3) is not satisfied, the movement of carriers in the charge transport layer is slow, and the high-speed response is inferior.

Moreover, in this embodiment, it is preferable to satisfy | fill following formula (4) further.
Formula (4) 0.5 ≦ μ (CTL) / μ (OCL) ≦ 5
(In formula (4), μ (CTL) represents the hole mobility of the charge transport layer at an electric field strength of 30 V / μm, and μ (OCL) represents the hole mobility of the surface protective layer at an electric field strength of 30 V / μm.)

  The difference in charge mobility between the charge transport layer and the surface protective layer is small, that is, by satisfying the formula (4), the accumulation of charge carriers at the interface is suppressed even when image formation is repeated over a long period of time. As a result, the increase in residual potential over time is suppressed. In addition, the ratio of charge carriers moving in the charge transport layer and the surface protective layer is small, that is, satisfying the formula (4), the charge carriers move quickly in the layer, and excellent high-speed response. Is obtained.

In addition, it is more preferable that said Formula (2) and Formula (3) satisfy | fill further following formula (2 ') and Formula (3'), respectively.
Formula (2 ′) | Ip (OCL) −Ip (CTL) | ≦ 0.2 (eV)
Formula (3 ′) μ (CTL) ≧ 2.5 × 10 ⁻⁵ [cm ² / Vs]
(In Formula (2 ′) and Formula (3 ′), Ip (CTL) is the ionization potential of the first charge transport material, Ip (OCL) is the ionization potential of the second charge transport material, μ ( (CTL) represents the hole mobility of the charge transport layer at an electric field strength of 30 V / μm.)

-Measurement of ionization potential-
The ionization potential means the amount of energy required to extract one electron from the material ground state. The ionization potential is measured by irradiating the sample with ultraviolet light that has been dispersed with a monochromator while changing the energy in an air atmosphere, and obtaining the energy at which photoelectrons start to be emitted by the photoelectric effect. The ionization potentials of the charge generation material, the first charge transport material, and the second charge transport material were measured using an atmospheric photoelectron spectrometer AC-2 manufactured by Riken Keiki Co., Ltd.

-Measurement of hole mobility-
The hole mobility is obtained from the applied voltage at that time and the thickness of the measurement sample by measuring the transient photocurrent waveform with respect to the amount of charge carrier movement. This is a charge carrier mobility measurement method commonly known as the so-called Time of Flight method (TOF method). The hole mobility of the charge transport layer and the surface protective layer was measured by the TOF method, and the numerical values described in this specification were values when the electric field strength was 30 V / μm.

-Control method-
Controlling the difference in ionization potential between the charge generating material and the first charge transporting material and the difference in ionization potential between the first charge transporting material and the second charge transporting material within an appropriate range, i.e., In order to control to satisfy the expressions (1) and (2) (and also the expression (2 ′)), the charge generation material used for the charge generation layer, the first charge transport material used for the charge transport layer, and the surface protective layer And a method of selecting the type of the second charge transporting material used for each.
Further, a method for controlling the moving speed of the charge carriers moving in the charge transporting layer to be high, that is, a method for controlling so as to satisfy the above formula (3) (or the formula (3 ′)), and the charge transporting layer, the surface protective layer, As a method for controlling the difference in charge mobility between the charge generation layer, the charge generation material used for the charge generation layer, the first charge transport material used for the charge transport layer, and the surface protective layer, Examples thereof include a method for selecting the type of the second charge transport material to be used and a method for adjusting the amount thereof.
A preferred combination of the charge generation material, the first charge transport material, and the second charge transport material will be described later.

  Next, the configuration of the photoconductor according to the present embodiment will be described.

Hereinafter, the configuration of the photoreceptor according to the present embodiment will be described with reference to FIG. 1, but the present embodiment is not limited to FIG. 1.
FIG. 1 is a schematic cross-sectional view showing an example of the layer structure of the photoreceptor according to this embodiment. In FIG. 1, 1 is a substrate, 2 is a photosensitive layer, 2A is a charge generation layer, 2B is a charge transport layer, 4 Represents an undercoat layer, and 5 represents a surface protective layer. The photoreceptor shown in FIG. 1 has a layer structure in which an undercoat layer 4, a charge generation layer 2A, a charge transport layer 2B, and a surface protective layer 5 are laminated in this order on a substrate 1.

-Substrate As the substrate 1, a conductive substrate is used, for example, a metal or an alloy such as aluminum, copper, zinc, stainless steel, chromium, nickel, molybdenum, vanadium, indium, gold, or platinum is used. Examples include metal plates, metal drums, and metal belts, or paper, plastic films, belts, etc. coated, vapor-deposited, or laminated with conductive polymers, conductive compounds such as indium oxide, and metals or alloys such as aluminum, palladium, and gold. It is done. Here, “conductive” means that the volume resistivity is less than 10 ¹³ Ωcm.

  When the photoreceptor shown in FIG. 1 is used in a laser printer, the surface of the substrate 1 is desirably roughened to a centerline average roughness Ra of 0.04 μm or more and 0.5 μm or less. However, when non-interfering light is used as a light source, roughening is not particularly required.

  Surface roughening methods include wet honing by suspending an abrasive in water and spraying it on the support, or centerless grinding and anodization in which the support is brought into contact with a rotating grindstone and continuously ground. Processing is desirable.

  Further, as another roughening method, without roughening the surface of the substrate 1, conductive or semiconductive powder is dispersed in the resin to form a layer on the surface of the support, A method of roughening with particles dispersed in the layer is also desirably used.

  Here, the roughening treatment by anodic oxidation is to form an oxide film on the aluminum surface by anodizing in an electrolyte solution using aluminum as an anode. Examples of the electrolyte solution include a sulfuric acid solution and an oxalic acid solution. However, since the porous anodic oxide film formed by anodic oxidation is chemically active as it is, fine pores of the anodic oxide film may be added to pressurized water vapor or boiling water (metal salt such as nickel may be added). It is desirable to perform a sealing treatment to block the volume expansion due to the hydration reaction, and to change to a more stable hydrated oxide. The thickness of the anodic oxide film is desirably 0.3 μm or more and 15 μm or less.

Further, the substrate 1 may be subjected to treatment with an acidic aqueous solution or boehmite treatment.
The treatment with an acidic treatment solution containing phosphoric acid, chromic acid and hydrofluoric acid is carried out as follows. First, an acidic treatment liquid is prepared. The mixing ratio of phosphoric acid, chromic acid and hydrofluoric acid in the acidic treatment liquid is such that phosphoric acid is in the range of 10% by mass to 11% by mass, chromic acid is in the range of 3% by mass to 5% by mass, and hydrofluoric acid is 0.00%. The concentration of these acids is preferably in the range of 13.5 mass% to 18 mass%. The treatment temperature is desirably 42 ° C. or higher and 48 ° C. or lower. The film thickness is preferably from 0.3 μm to 15 μm.

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

-Undercoat layer The undercoat layer 4 is comprised as a layer which contained the inorganic particle in binder resin, for example.
As the inorganic particles, those having a powder resistance (volume resistivity) of 10 ² Ω · cm to 10 ¹¹ Ω · cm are desirably used.

  Among these, inorganic particles (conductive metal oxide) such as tin oxide, titanium oxide, zinc oxide and zirconium oxide are preferably used as the inorganic particles having the above resistance value, and zinc oxide is particularly preferably used.

  In addition, the inorganic particles may be subjected to a surface treatment, or may be used as a mixture of two or more types such as those having different surface treatments or particles having different particle diameters. The volume average particle size of the inorganic particles is desirably in the range of 50 nm to 2000 nm (desirably 60 to 1000).

As the inorganic particles, those having a specific surface area of 10 m ² / g or more by the BET method are desirably used.

  Further, in addition to the inorganic particles, an acceptor compound may be contained. Any acceptor compound may be used. For example, quinone compounds such as chloranil and bromoanil, tetracyanoquinodimethane compounds, 2,4,7-trinitrofluorenone, 2,4,5,7- Fluorenone compounds such as tetranitro-9-fluorenone, 2- (4-biphenyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole and 2,5-bis (4-naphthyl)- Oxadiazole compounds such as 1,3,4-oxadiazole, 2,5-bis (4-diethylaminophenyl) 1,3,4-oxadiazole, xanthone compounds, thiophene compounds, 3,3 ′, Electron transporting substances such as diphenoquinone compounds such as 5,5′tetra-t-butyldiphenoquinone are desirable, and in particular, anthraquinone structure Compounds is desired. Furthermore, acceptor compounds having an anthraquinone structure such as hydroxyanthraquinone compounds, aminoanthraquinone compounds, aminohydroxyanthraquinone compounds, and the like are desirably used, and specific examples include anthraquinone, alizarin, quinizarin, anthralfin, and purpurin.

  The content of these acceptor compounds may be arbitrarily set, but is desirably 0.01% by mass or more and 20% by mass or less with respect to the inorganic particles. Furthermore, 0.05 mass% or more and 10 mass% or less are desirable.

  The acceptor compound may be added only when the undercoat layer 4 is applied, or may be previously attached to the surface of the inorganic particles. Examples of the method for imparting the acceptor compound to the surface of the inorganic particles include a dry method or a wet method.

  When surface treatment is performed by a dry method, the inorganic particles are treated by dropping an acceptor compound dissolved in an organic solvent directly or with dry air or nitrogen gas while stirring with a mixer having a large shearing force. The The addition or spraying is preferably performed at a temperature below the boiling point of the solvent. After addition or spraying, baking may be performed at 100 ° C. or higher. About baking temperature and time, it implements in arbitrary ranges.

  As the wet method, the inorganic particles are stirred in a solvent, dispersed using ultrasonic waves, a sand mill, an attritor, a ball mill, or the like, and after adding or accepting an acceptor compound, the solvent is removed. The solvent removal method is distilled off by filtration or distillation. After removing the solvent, baking may be performed at 100 ° C. or higher. About baking temperature and time, it implements in arbitrary ranges. In the wet method, the water containing inorganic particles may be removed before adding the surface treatment agent. For example, a method of removing with stirring and heating in a solvent used for the surface treatment, a method of removing by azeotropic distillation with the solvent. May be used.

  In addition, the inorganic particles may be subjected to a surface treatment before the acceptor compound is provided. The surface treatment agent is selected from known materials. For example, a silane coupling agent, a titanate coupling agent, an aluminum coupling agent, a surfactant, and the like can be given. In particular, a silane coupling agent is desirably used. Furthermore, a silane coupling agent having an amino group is also desirably used.

  Any material may be used as the silane coupling agent having an amino group. Specific examples include γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N- β- (aminoethyl) -γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane and the like can be mentioned. However, it is not limited to these.

  Two or more silane coupling agents may be mixed and used. Examples of silane coupling agents that may be used in combination with the silane coupling agent having an amino group include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3 , 4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -Γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyl Examples include trimethoxysilane. However, it is not limited to these.

  As the surface treatment method, any known method can be used, but a dry method or a wet method is preferably used. Moreover, you may perform acceptor provision and surface treatment by a coupling agent etc. in parallel.

  Although the quantity of the silane coupling agent with respect to the inorganic particle in the undercoat layer 4 is set arbitrarily, 0.5 mass% or more and 10 mass% or less are desirable with respect to an inorganic particle.

  As the binder resin contained in the undercoat layer 4, any known resin can be used. For example, acetal resin such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester Resins, methacrylic resins, acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate-maleic anhydride resins, silicone resins, silicone-alkyd resins, phenol resins, phenol-formaldehyde resins, melamine resins, urethane resins, etc. These known polymer resin compounds, charge transporting resins having a charge transporting group, conductive resins such as polyaniline, and the like are used. Among these, resins that are insoluble in the upper coating solvent are preferably used, and phenol resins, phenol-formaldehyde resins, melamine resins, urethane resins, epoxy resins, and the like are particularly preferable. When these are used in combination of two or more, the mixing ratio is set as necessary.

  In addition, the ratio of the metal oxide and binder resin which provided acceptor property in the coating liquid for undercoat layer formation or an inorganic particle and binder resin is set arbitrarily.

Various additives may be used in the undercoat layer 4. As additives, known materials such as polycyclic condensation type, azo type electron transporting pigments, zirconium chelate compounds, titanium chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, silane coupling agents and the like are used. It is done.
The silane coupling agent is used for the surface treatment of the metal oxide, but may be further added to the coating solution as an additive. Specific examples of the silane coupling agent used here include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ. -Glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β -(Aminoethyl) -γ-aminopropylmethyldimethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane and the like.
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 , 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, ethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate) and the like.

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

  The solvent for preparing the coating solution for forming the undercoat layer is selected from known organic solvents such as alcohols, aromatics, halogenated hydrocarbons, ketones, ketone alcohols, ethers, esters, etc. The Examples of the solvent include methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, n-butyl acetate, Usual organic solvents such as dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene and toluene are used.

  Moreover, you may use the solvent used for these dispersion | distribution individually or in mixture of 2 or more types. When mixing, any solvent can be used as long as it can dissolve the binder resin as the mixed solvent.

  As a dispersion method, known methods such as a roll mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker are used. Further, as the coating method used when the undercoat layer 4 is provided, conventional 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. Is used.

The undercoat layer 4 is formed on the substrate 1 using the coating solution for forming the undercoat layer thus obtained.
The undercoat layer 4 preferably has a Vickers strength of 35 or more.
Furthermore, the undercoat layer 4 may be set to any thickness, but the thickness is preferably 15 μm or more, and more preferably 15 μm or more and 50 μm or less.

  Further, the surface roughness (ten-point average roughness) of the undercoat layer 4 is preferably adjusted from ¼n (n is the refractive index of the upper layer) to ½λ of the exposure laser wavelength λ used. . In order to adjust the surface roughness, particles such as a resin may be added to the undercoat layer. As the resin particles, silicone resin particles, cross-linked polymethyl methacrylate resin particles and the like are used.

  Further, the undercoat layer may be polished for adjusting the surface roughness. As a polishing method, buffing, sandblasting, wet honing, grinding, or the like is used.

  The coated layer is dried to obtain an undercoat layer. Usually, the drying is performed at a temperature at which the solvent can be evaporated to form a film.

Charge generation layer The charge generation layer 2A is preferably a layer containing at least a charge generation material and a binder resin.
Examples of the charge generation material include azo pigments such as bisazo and trisazo, condensed aromatic pigments such as dibromoanthanthrone, perylene pigments, pyrrolopyrrole pigments, phthalocyanine pigments, zinc oxide, and trigonal selenium. Among these, metal and / or metal-free phthalocyanine pigments are desirable for near-infrared laser exposure. In particular, hydroxygallium disclosed in JP-A-5-263007, JP-A-5-279591, and the like. Phthalocyanine, chlorogallium phthalocyanine disclosed in JP-A-5-98181, dichlorotin phthalocyanine disclosed in JP-A-5-140472, JP-A-5-140473, etc., JP-A-4-189873, More preferred is titanyl phthalocyanine disclosed in JP-A-5-43823. For near-ultraviolet laser exposure, condensed aromatic pigments such as dibromoanthanthrone, thioindigo pigments, porphyrazine compounds, zinc oxide, and trigonal selenium are more desirable. As the charge generation material, an inorganic pigment is desirable when a light source having an exposure wavelength of 380 nm to 500 nm is used, and a metal and metal-free phthalocyanine pigment is desirable when a light source having an exposure wavelength of 700 nm to 800 nm is used.

  As the charge generation material, it is desirable to use a hydroxygallium phthalocyanine pigment having a maximum peak wavelength in a range of 810 nm to 839 nm in a spectral absorption spectrum in a wavelength range of 600 nm to 900 nm. This hydroxygallium phthalocyanine pigment is different from the conventional V-type hydroxygallium phthalocyanine pigment, and the maximum peak wavelength of the spectral absorption spectrum is shifted to a shorter wavelength side than the conventional V-type hydroxygallium phthalocyanine pigment. .

The hydroxygallium phthalocyanine pigment having the maximum peak wavelength in the range of 810 nm to 839 nm is preferably in a specific range for the average particle size and in a specific range for the BET specific surface area. Specifically, the average particle size is desirably 0.20 μm or less, more desirably 0.01 μm or more and 0.15 μm or less, while the BET specific surface area is desirably 45 m ² / g or more. 50 m ² / g or more is more desirable, and 55 m ² / g or more and 120 m ² / g or less is particularly desirable. The average particle size is a volume average particle size (d50 average particle size) measured by a laser diffraction / scattering particle size distribution analyzer (LA-700, manufactured by Horiba, Ltd.). Further, the BET specific surface area is a value measured by a nitrogen substitution method using a BET specific surface area measuring instrument (manufactured by Shimadzu Corporation: Flow Soap II2300).

  The maximum particle size (maximum primary particle size) of the hydroxygallium phthalocyanine pigment is desirably 1.2 μm or less, more desirably 1.0 μm or less, and further desirably 0.3 μm or less. is there.

Further, the hydroxygallium phthalocyanine pigment preferably has an average particle size of 0.2 μm or less, a maximum particle size of 1.2 μm or less, and a specific surface area value of 45 m ² / g or more.

  In addition, the hydroxygallium phthalocyanine pigment described above has Bragg angles (2θ ± 0.2 °) of 7.5 °, 9.9 °, 12.5 °, and 16.5 in an X-ray diffraction spectrum using CuKα characteristic X-rays. It is desirable to have diffraction peaks at 3 °, 18.6 °, 25.1 ° and 28.3 °.

  The hydroxygallium phthalocyanine pigment preferably has a thermal weight reduction rate of 2.0% or more and 4.0% or less when heated from 25 ° C. to 400 ° C., and preferably 2.5% or more and 3.8%. % Or less is more desirable. The thermogravimetric reduction rate is measured with a thermobalance.

The binder resin used for the charge generation layer 2A is selected from a wide range of insulating resins, and selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, polyvinylpyrene, and polysilane. Also good. Desirable binder resins include polyvinyl butyral resins, polyarylate resins (polycondensates of bisphenols and aromatic divalent carboxylic acids, etc.), polycarbonate resins, polyester resins, phenoxy resins, vinyl chloride-vinyl acetate copolymers, polyamides. Resins, acrylic resins, polyacrylamide resins, polyvinyl pyridine resins, cellulose resins, urethane resins, epoxy resins, caseins, polyvinyl alcohol resins, polyvinyl pyrrolidone resins, and the like. These binder resins are used alone or in combination of two or more. The blending ratio of the charge generation material and the binder resin is preferably in the range of 10: 1 to 1:10 by mass ratio. Here, “insulating” means that the volume resistivity is 10 ¹³ Ωcm or more.

The charge generation layer 2A is formed using, for example, a coating liquid in which the charge generation material and the binder resin are dispersed in a solvent.
Solvents used for dispersion include methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, and methylene chloride. , Chloroform, chlorobenzene, toluene and the like. These may be used alone or in admixture of two or more.

  Further, as a method for dispersing the charge generating material and the binder resin in the solvent, usual methods such as a ball mill dispersion method, an attritor dispersion method, and a sand mill dispersion method are used. Further, at the time of dispersion, it is effective that the average particle size of the charge generating material is 0.5 μm or less, desirably 0.3 μm or less, and more desirably 0.15 μm or less.

  Further, when forming the charge generation layer 2A, a usual method such as a blade coating method, a Mayer 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. .

  The film thickness of the charge generation layer 2A thus obtained is desirably 0.1 μm or more and 5.0 μm or less, and more desirably 0.2 μm or more and 2.0 μm or less.

Charge transport layer The charge transport layer 2B is preferably a layer containing at least a first charge transport material and a binder resin, or a layer containing a high molecular weight first charge transport material.
As the first charge transport material, quinone compounds such as p-benzoquinone, chloranil, bromanyl, anthraquinone, tetracyanoquinodimethane compounds, fluorenone compounds such as 2,4,7-trinitrofluorenone, xanthone compounds, Electron transport compounds such as benzophenone compounds, cyanovinyl compounds, ethylene compounds, triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted ethylene compounds, stilbene compounds, anthracene compounds, hydrazone compounds And hole transporting compounds such as These first charge transport materials may be used alone or in combination of two or more, but are not limited thereto.

  As the first charge transport material, a triarylamine derivative represented by the following structural formula (a-1) and a benzidine derivative represented by the following structural formula (a-2) are desirable.

(In Structural Formula (a-1), R ⁸ represents a hydrogen atom or a methyl group. N represents 1 or 2. Ar ⁶ and Ar ⁷ are each independently a substituted or unsubstituted aryl group, —C _6. H ₄ —C (R ⁹ ) ═C (R ¹⁰ ) (R ¹¹ ), or —C ₆ H ₄ —CH═CH—CH═C (R ¹² ) (R ¹³ ), wherein R ^{9 to} R ¹³ are Each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, including a halogen atom, an alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms; A substituted amino group substituted with a group or an alkyl group having 1 to 3 carbon atoms.)

(In Structural Formula (a-2), R ¹⁴ and R ^{14 ′} may be the same or different and each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or 1 to 5 carbon atoms. R ¹⁵ , R ^{15 ′} , R ¹⁶ and R ^{16 ′} may be the same or different and each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or 1 carbon atom. Or more, an alkoxy group having 5 or less, an amino group substituted with an alkyl group having 1 to 2 carbon atoms, a substituted or unsubstituted aryl group, -C (R ¹⁷ ) = C (R ¹⁸ ) (R ¹⁹ ), or- CH = CH—CH═C (R ²⁰ ) (R ²¹ ), wherein R ^{17 to} R ²¹ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. And n are independent of each other 0 or 2 show the following integer.)

Here, among the triarylamine derivatives represented by the structural formula (a-1) and the benzidine derivatives represented by the structural formula (a-2), in particular, “—C ₆ H ₄ —CH═CH—CH Triarylamine derivatives having “═C (R ¹² ) (R ¹³ )” and benzidine derivatives having “—CH═CH—CH═C (R ²⁰ ) (R ²¹ )” are desirable.

  Further, the first charge transport material is more preferably represented by the following (General Formula 1) or (General Formula 2).

(In the above (general formula 1), R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ , R ³⁶ may be the same or different and each represents a hydrogen atom, an alkyl group, an alkoxy group, a phenoxy group. Represents a halogen atom or an aryl group which may have a substituent, and m and n represent 0 or 1.)
In the above (General Formula 1), the alkyl group represented by R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ , R ³⁶ is an alkyl group having 1 to 4 carbon atoms, such as a methyl group or an ethyl group. , N-propyl group, isopropyl group, n-butyl group, isobutyl group and the like, and methyl group or ethyl group is particularly preferable.
Examples of the alkoxy group include an alkoxy group having 1 to 4 carbon atoms, such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group.
As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom etc. are mentioned, for example.
The aryl group which may have a substituent includes a phenyl group, a phenyl group substituted with a lower alkyl group such as a p-tolyl group and a 2,4-dimethylphenyl group, and a lower alkoxy group such as a p-methoxyphenyl group. Examples thereof include a phenyl group substituted with a halogen atom such as a substituted phenyl group and a p-chlorophenyl group.

(In the above (general formula 2), R ³⁷ , R ³⁸ , R ³⁹ , R ⁴⁰ , R ⁴¹ , R ⁴² , R ⁴³ may be the same or different, and each represents a hydrogen atom, an alkyl group, or an alkoxy group. , A phenoxy group, a halogen atom, or an aryl group which may have a substituent, m and n each represents 0 or 1)
In the above (General Formula 2), the alkyl group represented by R ³⁷ , R ³⁸ , R ³⁹ , R ⁴⁰ , R ⁴¹ , R ⁴² , R ⁴³ is an alkyl group having 1 to 4 carbon atoms, such as a methyl group , An ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and the like, and a methyl group or an ethyl group is particularly preferable.
Examples of the alkoxy group include an alkoxy group having 1 to 4 carbon atoms, such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group.
As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom etc. are mentioned, for example.
The aryl group which may have a substituent includes a phenyl group, a phenyl group substituted with a lower alkyl group such as a p-tolyl group and a 2,4-dimethylphenyl group, and a lower alkoxy group such as a p-methoxyphenyl group. Examples thereof include a phenyl group substituted with a halogen atom such as a substituted phenyl group and a p-chlorophenyl group.

  As the first charge transport material, the following compounds are particularly preferable.

  The binder resin used for the charge transport layer 2B 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 carbazole, polysilane, etc. are mentioned. Further, as described above, a polymer charge transport material such as a polyester-based polymer charge transport material disclosed in JP-A-8-176293 and JP-A-8-208820 may be used. These binder resins are used alone or in combination of two or more. The blending ratio of the first charge transport material and the binder resin is desirably 10: 1 to 1: 5 by mass ratio.

  The binder resin is not particularly limited, but at least one of a polycarbonate resin having a viscosity average molecular weight of 50,000 to 80,000 and a polyarylate resin having a viscosity average molecular weight of 50,000 to 80,000 is desirable.

  A polymer charge transport material may be used as the first charge transport material. As the polymer charge transporting material, known materials having charge transporting properties such as poly-N-vinylcarbazole and polysilane are used. In particular, polyester polymer charge transport materials disclosed in JP-A-8-176293 and JP-A-8-208820 are particularly desirable. Although the polymer charge transport material can be formed by itself, it may be formed by mixing with a binder resin described later.

  The charge transport layer 2B is formed using, for example, a charge transport layer forming coating solution containing the above-described constituent materials. Solvents used in 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, and halogenation such as methylene chloride, chloroform and ethylene chloride. Ordinary organic solvents such as aliphatic hydrocarbons, cyclic ethers such as tetrahydrofuran and ethyl ether, or straight chain ethers may be used alone or in admixture of two or more. Moreover, a well-known method is used as a dispersion method of each said constituent material.

  Coating methods for coating the charge transport layer forming coating solution on the charge generation layer 2A include blade coating method, Mayer bar coating method, spray coating method, dip coating method, bead coating method, air knife coating method, A usual method such as a curtain coating method is used.

  The film thickness of the charge transport layer 2B is desirably 5 μm or more and 50 μm or less, and more desirably 10 μm or more and 30 μm or less.

In the photoreceptor shown in FIG. 1, additives such as an antioxidant, a light stabilizer, and a heat stabilizer may be added to the charge generation layer and the charge transport layer. For example, examples of the antioxidant include hindered phenol, hindered amine, paraphenylenediamine, arylalkane, hydroquinone, spirochroman, spiroidanone and derivatives thereof, organic sulfur compounds, and organic phosphorus compounds. Examples of the light stabilizer include derivatives such as benzophenone, benzotriazole, dithiocarbamate, and tetramethylpiperidine.
Further, at least one kind of electron accepting substance may be contained. Examples of the electron acceptor that can be used include succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrabromophthalic anhydride, tetracyanoethylene, tetracyanoquinodimethane, o-dinitrobenzene, m- Examples include dinitrobenzene, chloranil, dinitroanthraquinone, trinitrofluorenone, picric acid, o-nitrobenzoic acid, p-nitrobenzoic acid, and phthalic acid. Among these, fluorenone compounds, quinone compounds and Cl-, CN-, NO 2 _- benzene derivatives having an electron attractive substituent, and the like are particularly preferable.

Surface protective layer As described above, the surface protective layer 5 in the photoreceptor shown in FIG. 1 contains the second charge transport material. In addition, it is more preferable to contain the following components (A) and (B), and the following component (C) may be further contained.
(A) a compound having a guanamine structure (guanamine compound) or a compound having a melamine structure (melamine compound) and at least one substituent selected from —OH, —OCH ₃ , —NH ₂ , —SH and —COOH (B) Fluorine resin particles (C) Other compositions of a compound containing a charge transporting material (hereinafter simply referred to as “specific charge transporting material”) having

  The at least one compound selected from the guanamine compound and the melamine compound has a solid content concentration of 0.1% by mass or more and 15% by mass or less in the composition containing the compound and the specific charge transporting material. desirable.

(A) the charge transporting material having a compound having a guanamine structure or a melamine structure and at least one substituent selected from —OH, —OCH ₃ , —NH ₂ , —SH and —COOH (specific charge) Compound containing Transport Material) The surface protective layer 5 in the photoreceptor shown in FIG. 1 preferably contains a crosslinked product in which a guanamine compound or melamine compound and a specific charge transport material are crosslinked. In addition, it is preferable that content of the charge transport material in the surface protective layer 5 is 80 to 99 mass%.

First, a compound having a guanamine structure (guanamine compound) will be described.
The guanamine compound is a compound having a guanamine skeleton (structure), and examples thereof include acetoguanamine, benzoguanamine, formoguanamine, steroguanamine, spiroguanamine, and cyclohexylguanamine.

  The guanamine compound is particularly preferably at least one of a compound represented by the following general formula (A) and a multimer thereof. Here, the multimer is an oligomer polymerized using the compound represented by the general formula (A) as a structural unit, and the degree of polymerization thereof is, for example, 2 or more and 200 or less (preferably 2 or more and 100 or less). In addition, the compound shown by general formula (A) may be used individually by 1 type, but may use 2 or more types together. In particular, the compound represented by the general formula (A) is preferably used as a mixture of two or more kinds or as a multimer (oligomer) having the structural unit as a structural unit.

In General Formula (A), R ¹ is a linear or branched alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted phenyl group having 6 to 10 carbon atoms, or 4 to 10 carbon atoms. The following substituted or unsubstituted alicyclic hydrocarbon groups are shown. R ^{2 to} R ⁵ each independently represent hydrogen, —CH ₂ —OH, or —CH ₂ —O—R ⁶ . R ⁶ represents hydrogen or a linear or branched alkyl group having 1 to 10 carbon atoms.

In the general formula (A), the alkyl group representing R ¹ has 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, more preferably 1 to 5 carbon atoms. . The alkyl group may be linear or branched.

In general formula (A), the phenyl group represented by R ¹ has 6 to 10 carbon atoms, and more preferably 6 to 8 carbon atoms. Examples of the substituent substituted with the phenyl group include a methyl group, an ethyl group, and a propyl group.

In general formula (A), the alicyclic hydrocarbon group representing R ¹ has 4 to 10 carbon atoms, and more preferably 5 to 8 carbon atoms. Examples of the substituent substituted with the alicyclic hydrocarbon group include a methyl group, an ethyl group, and a propyl group.

In the general formula (A), in “—CH ₂ —O—R ⁶ ” representing R ^{2 to} R ⁵ , the alkyl group representing R ⁶ has 1 to 10 carbon atoms, and desirably has carbon atoms. 1 or less and 8 or more, and more preferably 1 or more and 6 or less. The alkyl group may be linear or branched. Desirably, a methyl group, an ethyl group, a butyl group, etc. are mentioned.

As the compound represented by the general formula (A), it is particularly desirable that R ¹ represents a substituted or unsubstituted phenyl group having 6 to 10 carbon atoms, and R ^{2 to} R ⁵ are each independently —CH ₂ —O. It is a compound represented by —R ⁶ . R ⁶ is preferably selected from a methyl group and an n-butyl group.

  The compound represented by the general formula (A) is synthesized by a known method using, for example, guanamine and formaldehyde (for example, see Experimental Chemistry Course 4th edition, Vol. 28, page 430).

  Specific examples of the compound represented by the general formula (A) are shown below, but are not limited thereto. Moreover, although the following specific examples show the thing of a monomer, the multimer (oligomer) which uses these as a structural unit may be sufficient.

  Commercially available products of the compound represented by the general formula (A) include, for example, “Superbecamine (R) L-148-55, Superbecamine (R) 13-535, Superbecamine (R) L-145- 60, Super Becamine (R) TD-126 "or more manufactured by DIC Corporation," Nicarac BL-60, Nicalac BX-4000 "or more manufactured by Nippon Carbide Corporation, and the like.

  In addition, the compound represented by the general formula (A) (including multimers) can be used in a suitable solvent such as toluene, xylene, ethyl acetate, etc., in order to remove the influence of residual catalyst after synthesis or after purchasing a commercial product. It may be dissolved and washed with distilled water, ion exchange water or the like, or may be removed by treatment with an ion exchange resin.

Next, a compound having a melamine structure (melamine compound) will be described.
The melamine compound is a melamine skeleton (structure), and is preferably at least one of a compound represented by the following general formula (B) and a multimer thereof. Here, the multimer is an oligomer obtained by polymerizing the compound represented by the general formula (B) as a structural unit as in the general formula (A), and the degree of polymerization thereof is, for example, 2 or more and 200 or less (preferably 2 or more and 100). The following). In addition, the compound shown by General formula (B) or its multimer may be used individually by 1 type, but may use 2 or more types together. Moreover, you may use together with the compound shown by the said general formula (A), or its multimer. In particular, the compound represented by the general formula (B) is preferably used as a mixture of two or more kinds or as a multimer (oligomer) having the same as a structural unit.

In general formula (B), R ^{7 to} R ¹² each independently represent a hydrogen atom, —CH ₂ —OH, —CH ₂ —O—R ¹³ , and R ¹³ is branched from 1 to 5 carbon atoms. Or a good alkyl group. Examples of R ¹³ include a methyl group, an ethyl group, and a butyl group.

  The compound represented by the general formula (B) is synthesized by, for example, a known method using melamine and formaldehyde (for example, synthesized as in the melamine resin of Experimental Chemistry Course 4th edition, Volume 28, page 430). The

  Specific examples of the compound represented by the general formula (B) are shown below, but are not limited thereto. Moreover, although the following specific examples show the thing of a monomer, the multimer (oligomer) which uses these as a structural unit may be sufficient.

  As a commercial item of the compound represented by the general formula (B), for example, Super Melami No. 90 (manufactured by NOF Corporation), Super Becamine (R) TD-139-60 (manufactured by DIC), Uban 2020 (Mitsui Chemicals), Sumitex Resin M-3 (Sumitomo Chemical Industries), Nicarak MW-30 (Japan) Carbide).

  In addition, the compound represented by the general formula (B) (including multimers) is dissolved in an appropriate solvent such as toluene, xylene or ethyl acetate after synthesis or after purchase of a commercial product in order to remove the influence of residual catalyst. It may be washed with distilled water, ion exchange water or the like, or may be removed by treatment with ion exchange resin.

Next, a specific charge transport material will be described.
Examples of the specific charge transporting material include a substituent selected from —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH (hereinafter, simply referred to as “specific reactive functional group”). Those having at least one of ()) are preferred. In particular, as the specific charge transporting material, those having at least two of the specific reactive functional groups are preferably exemplified, and those having three are preferably mentioned.

The specific charge transporting material is preferably a compound represented by the following general formula (I).
_{^{F - ((- R 7 -X}} ) n1 (R 8) n3 -Y) n2 (I)
In general formula (I), F represents an organic group derived from a compound having a hole transporting ability, and R ⁷ and R ⁸ are each independently a linear or branched alkylene having 1 to 5 carbon atoms. N1 represents 0 or 1, n2 represents an integer of 1 or more and 4 or less, and n3 represents 0 or 1. X represents an oxygen, NH, or sulfur atom, and Y represents —OH, —OCH ₃ , —NH ₂ , —SH, or —COOH (ie, the specific reactive functional group described above).

  In general formula (I), as the compound having a hole transport ability in an organic group derived from a compound having a hole transport ability represented by F, an arylamine derivative is preferably exemplified. Preferred examples of the arylamine derivative include a triphenylamine derivative and a tetraphenylbenzidine derivative.

  The compound represented by the general formula (I) is preferably a compound represented by the following general formula (II).

In general formula (II), Ar ^{1 to} Ar ⁴ may be the same or different and each independently represents a substituted or unsubstituted aryl group, and Ar ⁵ represents a substituted or unsubstituted aryl group or a substituted or unsubstituted group. D represents — (— R ⁷ —X) _n1 (R ⁸ ) _n3 —Y, c represents 0 or 1 independently, k represents 0 or 1, and the total number of D is 1 or more and 4 or less. R ⁷ and R ⁸ each independently represents a linear or branched alkylene group having 1 to 5 carbon atoms, n1 represents 0 or 1, n3 represents 0 or 1, and X represents oxygen , NH, or a sulfur atom, and Y represents —OH, —OCH ₃ , —NH ₂ , —SH, or —COOH.

In the general formula (II), “— (— R ⁷ —X) _n1 (R ⁸ ) _n3 —Y” representing D is the same as in the general formula (I), and R ⁷ and R ⁸ are each independently carbon. A linear or branched alkylene group having a number of 1 or more and 5 or less. N1 is preferably 1. X is preferably oxygen. Y is preferably a hydroxyl group.

  The total number of D in the general formula (II) corresponds to n2 in the general formula (I), preferably 2 or more and 4 or less, and more preferably 3 or more and 4 or less. That is, in the general formula (I) or the general formula (II), it is desirable to have the above-mentioned specific reactive functional group, desirably 2 to 4 and more desirably 3 to 4 in one molecule.

In general formula (II), Ar ^{1 to} Ar ⁴ are preferably any of the following formulas (1) to (7). The following formulas (1) to (7) are shown together with “-(D) _c ” that can be linked to each of Ar ^{1 to} Ar ⁴ .

[In the formulas (1) to (7), R ⁹ is substituted with a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. Represents one selected from the group consisting of a phenyl group, an unsubstituted phenyl group, and an aralkyl group having 7 to 10 carbon atoms, wherein R ^{10 to} R ¹² are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, carbon 1 selected from the group consisting of an alkoxy group having 1 to 4 carbon atoms, a phenyl group substituted with an alkoxy group having 1 to 4 carbon atoms, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom. Represents a seed, Ar represents a substituted or unsubstituted arylene group, D and c are the same as “D” and “c” in formula (II), s represents 0 or 1, and t represents 1 3 or more It represents an integer. ]

  Here, as Ar in Formula (7), what is represented by following formula (8) or (9) is desirable.

[In formulas (8) and (9), R ¹³ and R ¹⁴ are each a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. 1 represents one selected from the group consisting of a phenyl group substituted with, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms and a halogen atom, and t represents an integer of 1 to 3. ]

  Further, Z ′ in the formula (7) is preferably represented by any one of the following formulas (10) to (17).

[In the formulas (10) to (17), R ¹⁵ and R ¹⁶ are each a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. 1 represents one selected from the group consisting of a phenyl group substituted with, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom, W represents a divalent group, q and r each represent Represents an integer of 1 to 10, and t represents an integer of 1 to 3. ]

  W in the formulas (16) to (17) is preferably any one of divalent groups represented by the following (18) to (26). However, in formula (25), u represents an integer of 0 or more and 3 or less.

In general formula (II), Ar ⁵ is the aryl group of the above (1) to (7) exemplified in the description of Ar ^{1 to} Ar ⁴ when k is 0, and when k is 1, An arylene group obtained by removing one hydrogen atom from the above aryl groups (1) to (7) is desirable.

  Specific examples of the compound represented by the general formula (I) include the following compounds (I-1) to (I-34). In addition, the compound shown by the said general formula (I) is not limited at all by these.

  The solid content concentration of the specific charge transporting material in the composition is desirably 80% by mass or more, and more desirably 90% by mass or more. The upper limit of the solid content concentration is not limited as long as at least one selected from guanamine compounds and melamine compounds and other additives function effectively.

  The solid content concentration in at least one coating liquid selected from a guanamine compound and a melamine compound is preferably 0.1% by mass or more and 15% by mass or less, and more preferably 1% by mass or more and 10% by mass or less. It is.

The content of the specific charge transport material in the surface protective layer 5 is controlled by adjusting the specific charge transport material in the composition. The solid content concentration is desirably 0.1% by mass or more and 15% by mass or less, and more desirably 1% by mass or more and 10% by mass or less.
The content of at least one selected from the specific charge transporting material or the guanamine compound and the melamine compound in the surface protective layer 5 adjusts the solid content concentration of these compounds in the composition. Is controlled by

(B) Fluorine resin particles The surface protective layer 5 may contain fluorine resin particles. The fluororesin particles are not particularly limited, but include tetrafluoroethylene resin (PTFE), trifluoroethylene chloride resin, hexafluoropropylene resin, vinyl fluoride resin, vinylidene fluoride resin, 2 It is desirable to select one or two or more kinds of fluorinated ethylene chloride resins and copolymers thereof, more preferably tetrafluoroethylene resin and vinylidene fluoride resin, particularly preferably 4 fluorocarbon resins. It is a hydrogenated ethylene resin.

The average primary particle size of the fluororesin particles is preferably 0.05 μm or more and 1 μm or less, and more preferably 0.1 μm or more and 0.5 μm or less.
The average primary particle size of the fluororesin particles was measured by diluting with the same solvent as the dispersion in which the fluororesin particles were dispersed, using a laser diffraction particle size distribution analyzer LA-920 (manufactured by Horiba). A value obtained by measuring the liquid at a refractive index of 1.35.

  The content of the fluorine-based resin particles with respect to the total solid content of the protective layer 5 which is the outermost surface layer is preferably 1% by mass or more and 30% by mass or less, and more preferably 2% by mass or more and 20% by mass or less.

Further, the surface protective layer 5 may further contain a fluorinated alkyl group-containing copolymer.
The fluorinated alkyl group-containing copolymer is not particularly limited, but is preferably a fluorine-based graft polymer containing repeating units represented by the following structural formulas (1) and (2). More preferred is a resin synthesized by, for example, graft polymerization using a macromonomer composed of acrylate compound, methacrylic ester compound, etc., and perfluoroalkylethyl (meth) acrylate and perfluoroalkyl (meth) acrylate. . Here, (meth) acrylate represents acrylate or methacrylate.

[In structural formula (1) and structural formula (2), l, m and n are 1 or more positive numbers, p, q, r and s are 0 or 1 or more positive numbers, and t is 1 or more and 7 or less. Wherein R ₁ , R ₂ , R ₃ and R ₄ are a hydrogen atom or an alkyl group, X is an alkylene chain, a halogen-substituted alkylene chain, —S—, —O—, —NH— or a single bond, Y is an alkylene chain, a halogen-substituted alkylene _{chain, - (C z H 2z-} 1 (OH)) - or a single bond, z is 1 or more positive, Q is represents -O- or -NH-. ]

  The weight average molecular weight of the fluorinated alkyl group-containing copolymer is preferably from 10,000 to 100,000, and more preferably from 30,000 to 100,000.

  In the fluorinated alkyl group-containing copolymer, the content ratio of the structural formula (1) to the structural formula (2), that is, l: m is preferably 1: 9 to 9: 1, and more preferably 3: 7 to 7: 3. desirable.

In Structural Formula (1) and Structural Formula (2), examples of the alkyl group represented by R ₁ , R ₂ , R _3, and R ₄ include a methyl group, an ethyl group, and a propyl group. R ₁ , R ₂ , R ₃ and R ₄ are preferably a hydrogen atom or a methyl group, and more preferably a methyl group.

  The fluorinated alkyl group-containing copolymer may further contain a repeating unit represented by the structural formula (3). The content of the structural formula (3) is preferably 10: 0 to 7: 3 as l + m: z in the ratio of the total content of the structural formula (1) and the structural formula (2), that is, l + m, and 9: 1 7 to 3 is more desirable.

Structural formula (3)

[In Structural Formula (3), R ₅ and R ₆ represent a hydrogen atom or an alkyl group, and z represents a positive number of 1 or more. ]

R ₅ and R ₆ are preferably a hydrogen atom, a methyl group, or an ethyl group, and more preferably a methyl group.

  The content of the fluorinated alkyl group-containing copolymer in the protective layer 5 which is the outermost surface layer is desirably 1% by mass or more and 10% by mass or less with respect to the mass of the fluorine-based resin particles.

(C) Other composition The surface protective layer 5 includes a phenol resin, a melamine, and a cross-linked product obtained by cross-linking at least one selected from the above-described guanamine compounds and melamine compounds and a specific charge transporting material. You may mix and use other thermosetting resins, such as resin, urea resin, alkyd resin, and benzoguanamine resin. In addition, a compound having a larger number of functional groups in one molecule such as a spiroacetal guanamine resin (for example, “CTU-guanamine” (Ajinomoto Fine Techno Co., Ltd.)) may be copolymerized with the material in the crosslinked product.

  Further, a surfactant may be added to the surface protective layer 5. As the surfactant to be used, a surfactant containing at least one kind of structure among a fluorine atom, an alkylene oxide structure, and a silicone structure is preferably exemplified.

  Various things are mentioned as surfactant which has a fluorine atom. Specific examples of the surfactant having a fluorine atom and an acrylic structure include Polyflow KL600 (manufactured by Kyoeisha Chemical Co., Ltd.), F-top EF-351, EF-352, EF-801, EF-802, EF-601 (above, JEMCO Manufactured). The surfactant having an acrylic structure mainly includes those obtained by polymerizing or copolymerizing monomers such as acrylic or methacrylic compounds.

  Examples of the surfactant having a fluorine atom include surfactants having a perfluoroalkyl group, and more specifically, perfluoroalkylsulfonic acids (for example, perfluorobutanesulfonic acid, perfluorooctane). Suitable examples include sulfonic acids and the like, perfluoroalkyl carboxylic acids (for example, perfluorobutane carboxylic acid and perfluorooctane carboxylic acid), and perfluoroalkyl group-containing phosphate esters. Perfluoroalkylsulfonic acids and perfluoroalkylcarboxylic acids may be salts thereof and amide-modified products thereof.

  Examples of commercially available perfluoroalkyl sulfonic acids include MegaFuck F-114 (manufactured by Dainippon Ink & Chemicals, Inc.), F-top EF-101, EF102, EF-103, EF-104, EF-105, and EF-. 112, EF-121, EF-122A, EF-122B, EF-122C, EF-123A (manufactured by JEMCO), AK, 501 (manufactured by Neos) and the like.

  Examples of commercially available perfluoroalkyl carboxylic acids include Megafac F-410 (Dainippon Ink Chemical Co., Ltd.), F-Top EF-201, EF-204 (above, JEMCO).

  As commercial products of perfluoroalkyl group-containing phosphates, MegaFac F-493, F-494 (above, manufactured by Dainippon Ink & Chemicals, Inc.) F-top EF-123A, EF-123B, EF-125M, EF -132 (above, manufactured by JEMCO).

  Examples of the surfactant having an alkylene oxide structure include polyethylene glycol, polyether antifoaming agent, and polyether-modified silicone oil. The polyethylene glycol preferably has a number average molecular weight of 2000 or less, and the polyethylene glycol having a number average molecular weight of 2000 or less includes polyethylene glycol 2000 (number average molecular weight 2000), polyethylene glycol 600 (number average molecular weight 600), polyethylene glycol 400. (Number average molecular weight 400), polyethylene glycol 200 (number average molecular weight 200) and the like.

  Moreover, as a polyether antifoamer, PE-M, PE-L (above, Wako Pure Chemical Industries Ltd. make), antifoam No. 1. Antifoaming agent No. 1 5 (above, manufactured by Kao Corporation).

  Examples of the surfactant having a silicone structure include general silicone oils such as dimethyl silicone, methylphenyl silicone, diphenyl silicone, and derivatives thereof.

  Furthermore, surfactants having both a fluorine atom and an alkylene oxide structure include those having an alkylene oxide structure or a polyalkylene structure in the side chain, and the end of the alkylene oxide or polyalkylene oxide structure substituted with a substituent containing fluorine. And the like. Specific examples of the surfactant having an alkylene oxide structure include, for example, Megafac F-443, F-444, F-445, and F-446 (above, Dainippon Ink & Chemicals, Inc.), POLY FOX PF636. , PF6320, PF6520, PF656 (above, manufactured by Kitamura Chemical Co., Ltd.).

  As surfactants having both an alkylene oxide structure and a silicone structure, KF351 (A), KF352 (A), KF353 (A), KF354 (A), KF355 (A), KF615 (A), KF618, KF945 (A), KF6004 (above, manufactured by Shin-Etsu Chemical Co., Ltd.), TSF4440, TSF4445, TSF4450, TSF4446, TSF4452, TSF4453, TSF4460 (above, manufactured by GE Toshiba Silicon), BYK-300, 302, 306, 307, 310, 315, 320, 322, 323, 325, 330, 331, 333, 337, 341, 344, 345, 346, 347, 348, 370, 375, 377, 378, UV3500, UV3510, UV3570, etc. (above, Big Chemie Ja Emissions Co., Ltd.) and the like.

  The content of the surfactant is desirably 0.01% by mass or more and 1% by mass or less, and more desirably 0.02% by mass or more and 0.5% by mass or less with respect to the solid content of the surface protective layer 5.

  Further, the surface protective layer 5 may be further mixed with another coupling agent or a fluorine compound. As this compound, various silane coupling agents and commercially available silicone hard coat agents are used.

  As the silane coupling agent, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, and the like are used. As a commercially available hard coat agent, KP-85, X-40-9740, X-8239 (manufactured by Shin-Etsu Silicone), AY42-440, AY42-441, AY49-208 (manufactured by Toray Dow Corning) Etc. are used.

  In order to impart water repellency and the like, (tridecafluoro-1,1,2,2-tetrahydrooctyl) triethoxysilane, (3,3,3-trifluoropropyl) trimethoxysilane, 3- (hepta) Fluoroisopropoxy) propyltriethoxysilane, 1H, 1H, 2H, 2H-perfluoroalkyltriethoxysilane, 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane, 1H, 1H, 2H, 2H-perfluorooctyl Fluorine-containing compounds such as triethoxysilane may be added. Although the silane coupling agent is used in an arbitrary amount, the amount of the fluorine-containing compound is desirably 0.25 times or less by mass with respect to the compound not containing fluorine.

Further, a resin that dissolves in alcohol may be added to the surface protective layer 5.
Here, the alcohol-soluble resin means a resin that dissolves 1% by mass or more in an alcohol having 5 or less carbon atoms. Examples of resins that are soluble in alcohol solvents include polyvinyl acetal resins such as polyvinyl butyral resin, polyvinyl formal resin, and partially acetalized polyvinyl acetal resin in which a part of butyral is modified with formal or acetoacetal (for example, manufactured by Sekisui Chemical Co., Ltd.) ESREC B, K, etc.), polyamide resin, cellulose resin, polyvinylphenol resin and the like. In particular, polyvinyl acetal resin and polyvinyl phenol resin are desirable. The resin preferably has a weight average molecular weight of 2,000 to 100,000, and more preferably 5,000 to 50,000. The amount of the resin added is preferably 1% by mass or more and 40% by mass or less, more preferably 1% by mass or more and 30% by mass or less, and further preferably 5% by mass or more and 20% by mass or less.

  An antioxidant may be added to the surface protective layer 5. Antioxidants are preferably hindered phenols or hindered amines, organic sulfur antioxidants, phosphite antioxidants, dithiocarbamate antioxidants, thiourea antioxidants, benzimidazole antioxidants. , Etc., may be used. The addition amount of the antioxidant is preferably 20% by mass or less, and more preferably 10% by mass or less.

  Examples of the hindered phenol antioxidant include 2,6-di-t-butyl-4-methylphenol, 2,5-di-t-butylhydroquinone, N, N′-hexamethylene bis (3,5-di). -T-butyl-4-hydroxyhydrocinnamide, 3,5-di-t-butyl-4-hydroxy-benzylphosphonate-diethyl ester, 2,4-bis [(octylthio) methyl] -o-cresol, 2,6-di-t-butyl-4-ethylphenol, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'-methylenebis (4-ethyl-6-t-butylphenol) 4,4'-butylidenebis (3-methyl-6-t-butylphenol), 2,5-di-t-amylhydroquinone, 2-t-butyl-6- (3-butyl-2- Dorokishi-5-methylbenzyl) -4-methylphenyl acrylate, 4,4'-butylidene bis (3-methyl -6-t-butylphenol) and the like.

  Commercially available hindered phenolic antioxidants include “Irganox 1076”, “Irganox 1010”, “Irganox 1098”, “Irganox 245”, “Irganox 1330”, “Irganox 3114”. , “Irganox 1076”, “3,5-di-t-butyl-4-hydroxybiphenyl” and the like.

  As the hindered amine antioxidants, “Sanol LS2626”, “Sanol LS765”, “Sanol LS770”, “Sanol LS744”, “Tinuvin 144”, “Tinuvin 622LD”, “Mark LA57”, “Mark LA67”, “Mark” LA62 "," Mark LA68 ", and" Mark LA63 "are listed," Sumizer-TPS "and" Smilizer TP-D "are listed as thioethers, and" Mark 2112 "and" Mark PEP-8 "are listed as phosphites. , “Mark PEP-24G”, “Mark PEP-36”, “Mark 329K”, “Mark HP-10”, and the like.

  Furthermore, various particles may be added to the surface protective layer 5. An example of the particles is silicon-containing particles. Silicon-containing particles are particles containing silicon as a constituent element, and specific examples include colloidal silica and silicone particles. The colloidal silica used as the silicon-containing particles is obtained by dispersing silica having an average particle diameter of 1 nm or more and 100 nm or less, preferably 10 nm or more and 30 nm or less in an organic solvent such as an acidic or alkaline aqueous dispersion, alcohol, ketone, or ester. A commercially available product may be used. The solid content of colloidal silica in the protective layer 5 is not particularly limited, but is 0.1% by mass or more and 50% by mass or less, preferably 0.1% by mass based on the solid content of the protective layer 5. % Or more and 30% by mass or less.

  The silicone particles used as the silicon-containing particles are selected from silicone resin particles, silicone rubber particles, and silicone surface-treated silica particles, and those commercially available are generally used. These silicone particles are spherical, and the average particle size is desirably 1 nm or more and 500 nm or less, and more desirably 10 nm or more and 100 nm or less. The content of the silicone particles in the protective layer 5 is preferably 0.1% by mass or more and 30% by mass or less, more preferably 0.5% by mass or more and 10% by mass or less, based on the solid content of the protective layer 5. .

Other particles include fluorine-based particles such as ethylene tetrafluoride, ethylene trifluoride, propylene hexafluoride, vinyl fluoride, vinylidene fluoride, and “8th Polymer Material Forum Lecture Proceedings p89”. As shown, particles made of a resin obtained by copolymerizing a fluororesin and a monomer having a hydroxyl group, ZnO—Al ₂ O ₃ , SnO ₂ —Sb ₂ O ₃ , In ₂ O ₃ —SnO ₂ , ZnO ₂ —TiO ₂ , ZnO Examples thereof include semiconductive metal oxides such as —TiO ₂ , MgO—Al ₂ O ₃ , FeO—TiO ₂ , TiO ₂ , SnO ₂ , In ₂ O ₃ , ZnO, and MgO. For the same purpose, an oil such as silicone oil may be added. Silicone oils include silicone oils such as dimethylpolysiloxane, diphenylpolysiloxane, and phenylmethylsiloxane; amino-modified polysiloxane, epoxy-modified polysiloxane, carboxyl-modified polysiloxane, carbinol-modified polysiloxane, methacryl-modified polysiloxane, mercapto-modified poly Reactive silicone oils such as siloxane and phenol-modified polysiloxane; cyclic dimethylcyclosiloxanes such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane and dodecamethylcyclohexasiloxane; 1,3,5- Trimethyl-1,3,5-triphenylcyclotrisiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetraphenylcyclo Cyclic methylphenylcyclosiloxanes such as trasiloxane, 1,3,5,7,9-pentamethyl-1,3,5,7,9-pentaphenylcyclopentasiloxane; cyclic phenylcyclosiloxanes such as hexaphenylcyclotrisiloxane Fluorine-containing cyclosiloxanes such as (3,3,3-trifluoropropyl) methylcyclotrisiloxane; hydrosilyl group-containing cyclosiloxanes such as methylhydrosiloxane mixtures, pentamethylcyclopentasiloxane, and phenylhydrocyclosiloxane; penta And vinyl group-containing cyclosiloxanes such as vinylpentamethylcyclopentasiloxane.

  Further, metal, metal oxide, carbon black, or the like may be added to the surface protective layer 5. Examples of the metal include aluminum, zinc, copper, chromium, nickel, silver and stainless steel, or those obtained by depositing these metals on the surface of plastic particles. Examples of the metal oxide include zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, indium oxide doped with tin, tin oxide doped with antimony and tantalum, and zirconium oxide doped with antimony. . These may be used alone or in combination of two or more. When two or more types are used in combination, they may be simply mixed, or may be in the form of a solid solution or fusion. The average particle diameter of the conductive particles is preferably 0.3 μm or less, particularly preferably 0.1 μm or less, from the viewpoint of transparency of the protective layer.

  The surface protective layer 5 may contain a curing catalyst for accelerating the curing of the guanamine compound and the melamine compound or the specific charge transport material. An acid catalyst is preferably used as the curing catalyst. Acid-based catalysts include acetic acid, chloroacetic acid, trichloroacetic acid, trifluoroacetic acid, oxalic acid, maleic acid, malonic acid, lactic acid and other aliphatic carboxylic acids, benzoic acid, phthalic acid, terephthalic acid, trimellitic acid, etc. Aromatic carboxylic acids, methane sulfonic acids, dodecyl sulfonic acids, benzene sulfonic acids, aliphatics such as dodecyl benzene sulfonic acids, naphthalene sulfonic acids, and aromatic sulfonic acids are used, but sulfur-containing materials should be used. desirable.

  The sulfur-containing material as the curing catalyst is desirably one that exhibits acidity at room temperature (for example, 25 ° C.) or after heating, and is most desirably at least one of organic sulfonic acids and derivatives thereof. The presence of these catalysts in the surface protective layer 5 is easily confirmed by energy dispersive X-ray analysis (EDS), X-ray photoelectron spectroscopy (XPS) or the like.

  Examples of the organic sulfonic acid and / or a derivative thereof include p-toluenesulfonic acid, dinonylnaphthalenesulfonic acid (DNNSA), dinonylnaphthalenedisulfonic acid (DNNDSA), dodecylbenzenesulfonic acid, and phenolsulfonic acid. Among these, p-toluenesulfonic acid and dodecylbenzenesulfonic acid are desirable. Moreover, as long as it can dissociate in a curable resin composition, you may use an organic sulfonate.

Further, a so-called thermal latent catalyst, which has a high catalytic ability when heated, may be used.
As a heat latent catalyst, for example, a microcapsule in which an organic sulfone compound or the like is encapsulated in a polymer form, an adsorbed acid or the like on a pore compound such as zeolite, and a proton acid and / or proton acid derivative is blocked with a base Thermal latent proton acid catalyst, proton acid and / or proton acid derivative esterified with primary or secondary alcohol, proton acid and / or proton acid derivative blocked with vinyl ethers and / or vinyl thioethers , Boron trifluoride monoethylamine complex, boron trifluoride pyridine complex, and the like.

Of these, a protonic acid and / or a protonic acid derivative blocked with a base is desirable.
As the protonic acid of the heat latent protonic acid catalyst, sulfuric acid, hydrochloric acid, acetic acid, formic acid, nitric acid, phosphoric acid, sulfonic acid, monocarboxylic acid, polycarboxylic acids, propionic acid, oxalic acid, benzoic acid, acrylic acid, methacrylic acid, Itaconic acid, phthalic acid, maleic acid, benzenesulfonic acid, o, m, p-toluenesulfonic acid, styrenesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, decylbenzenesulfonic acid, undecylbenzenesulfonic acid, Examples include tridecylbenzenesulfonic acid, tetradecylbenzenesulfonic acid, dodecylbenzenesulfonic acid and the like. In addition, as protonic acid derivatives, neutralized products such as alkali metal salts of alkaline acids or alkaline earth metal circles such as sulfonic acid and phosphoric acid, and polymer compounds in which a protonic acid skeleton is introduced into the polymer chain (polyvinylsulfone) Acid, etc.). Examples of the base that blocks the protonic acid include amines.

  Amines are classified as primary, secondary or tertiary amines. There is no restriction in particular and any of them may be used.

  Examples of the primary amine include methylamine, ethylamine, propylamine, isopropylamine, n-butylamine, isobutylamine, t-butylamine, hexylamine, 2-ethylhexylamine, secondary butylamine, allylamine, and methylhexylamine.

  As secondary amines, dimethylamine, diethylamine, di-n-propylamine, diisopropylamine, di-n-butylamine, diisobutylamine, di-t-butylamine, dihexylamine, di (2-ethylhexyl) amine, N-isopropyl N-isobutylamine , Di (2-ethylhexyl) amine, disecondary butylamine, diallylamine, N-methylhexylamine, 3-pipecoline, 4-pipecoline, 2,4-lupetidine, 2,6-lupetidine, 3,5-lupetidine, morpholine, N -Methylbenzylamine and the like.

  As tertiary amines, trimethylamine, triethylamine, tri-n-propylamine, triisopropylamine, tri-n-butylamine, triisobutylamine, tri-t-butylamine, trihexylamine, tri (2-ethylhexyl) amine, N-methylmorpholine, N, N-dimethylallylamine, N-methyldiallylamine, triallylamine, N, N-dimethylallylamine, N, N, N ′, N′-tetramethyl-1,2-diaminoethane, N, N, N ′, N′-tetramethyl-1,3 -Diaminopropane, N, N, N ', N'-tetraallyl-1,4-diaminobutane, N-methylpiperidine, pyridine, 4-ethylpyridine, N-propyldiallylamine, 3-dimethylaminopropanol, 2-ethylpyrazine, 2, 3-di Tilpyrazine, 2,5-dimethylpyrazine, 2,4-lutidine, 2,5-lutidine, 3,4-lutidine, 3,5-lutidine, 2,4,6-collidine, 2-methyl-4-ethylpyridine, 2-methyl-5-ethylpyridine, N, N, N ′, N′-tetramethylhexamethylenediamine, N-ethyl-3-hydroxypiperidine, 3-methyl-4-ethylpyridine, 3-ethyl-4-methyl Pyridine, 4- (5-nonyl) pyridine, imidazole, N-methylpiperazine and the like can be mentioned.

Commercially available products include “NACURE2501” (toluenesulfonic acid dissociation, methanol / isopropanol solvent, pH 6.0 to pH 7.2, dissociation temperature 80 ° C.), “NACURE2107” (p-toluenesulfonic acid dissociation, manufactured by King Industries, Inc. Isopropanol solvent, pH 8.0 to pH 9.0, dissociation temperature 90 ° C.) “NACURE 2500” (p-toluenesulfonic acid dissociation, isopropanol solvent, pH 6.0 to pH 7.0, dissociation temperature 65 ° C.), “NACURE 2530” (P-toluenesulfonic acid dissociation, methanol / isopropanol solvent, pH 5.7 to pH 6.5, dissociation temperature 65 ° C.), “NACURE2547” (p-toluenesulfonic acid dissociation, aqueous solution, pH 8.0 to pH 9.0, Dissociation temperature 107 ), “NACURE2558” (p-toluenesulfonic acid dissociation, ethylene glycol solvent, pH 3.5 to pH4.5, dissociation temperature 80 ° C.), “NACUREXP-357” (p-toluenesulfonic acid dissociation, methanol solvent, pH 2. 0 to pH 4.0, dissociation temperature 65 ° C.) “NACUREXP-386” (p-toluenesulfonic acid dissociation, aqueous solution, pH 6.1 to pH 6.4, dissociation temperature 80 ° C.), “NACUREX C-2211” (p -Toluenesulfonic acid dissociation, pH 7.2 to pH 8.5, dissociation temperature 80 ° C.), “NACURE 5225” (dodecylbenzenesulfonic acid dissociation, isopropanol solvent, pH 6.0 to pH 7.0, dissociation temperature 120 ° C.), “ NACURE 5414 "(dodecylbenzenesulfonic acid dissociation, key Ren solvent, dissociation temperature 120 ° C.), “NACURE 5528” (dodecylbenzenesulfonic acid dissociation, isopropanol solvent, pH 7.0 to pH 8.0, dissociation temperature 120 ° C.), “NACURE 5925” (dodecylbenzenesulfonic acid dissociation, pH 7.0) PH 7.5 or less, dissociation temperature 130 ° C., “NACURE 1323” (disinyl naphthalene sulfonic acid dissociation, xylene solvent, pH 6.8 to pH 7.5, dissociation temperature 150 ° C.), “NACURE 1419” (dinonyl naphthalene sulfonic acid Dissociation, xylene / methyl isobutyl ketone solvent, dissociation temperature 150 ° C.), “NACURE1557” (dinonylnaphthalenesulfonic acid dissociation, butanol / 2-butoxyethanol solvent, pH 6.5 to pH 7.5, dissociation temperature 150 ° C.), “ NA CUREX 49-110 ”(dinonyl naphthalene disulfonic acid dissociation, isobutanol / isopropanol solvent, pH 6.5 to pH 7.5, dissociation temperature 90 ° C.),“ NACURE 3525 ”(dinonyl naphthalene disulfonic acid dissociation, isobutanol / isopropanol solvent, pH 7.0 to pH 8.5, dissociation temperature 120 ° C., “NACUREXP-383” (dinonyl naphthalene disulfonic acid dissociation, xylene solvent, dissociation temperature 120 ° C.), “NACURE 3327” (dinonyl naphthalene disulfonic acid dissociation, isobutanol / Isopropanol solvent, pH 6.5 to pH 7.5, dissociation temperature 150 ° C.), “NACURE4167” (phosphoric acid dissociation, isopropanol / isobutanol solvent, pH 6.8 to pH 7.3, dissociation temperature 80 ), “NACUREXP-297” (phosphoric acid dissociation, water / isopropanol solvent, pH 6.5 to pH 7.5, dissociation temperature 90 ° C., “NACURE 4575” (phosphoric acid dissociation, pH 7.0 to pH 8.0, dissociation temperature) 110 ° C.).
These thermal latent catalysts may be used alone or in combination of two or more.

  Here, the compounding amount of the catalyst is in the range of 0.1% by mass or more and 50% by mass or less with respect to at least one amount selected from the guanamine compound and the melamine compound (solid content concentration in the coating solution). Is desirable, and 10 mass% or more and 30 mass% or less are especially desirable.

(Method for forming surface protective layer)
The surface protective layer 5 having the above-described configuration is formed using a surface protective layer coating solution containing at least one selected from a guanamine compound and a melamine compound and a specific charge transporting material. In this coating solution for the surface protective layer, optional components of the surface protective layer 5 are added as necessary.

  The surface protective layer 5 is formed in the absence of a solvent or, if necessary, alcohols such as methanol, ethanol, propanol and butanol; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran, diethyl ether and dioxane; You may carry out using a solvent. Such solvents are used singly or in combination of two or more, and preferably have a boiling point of 100 ° C. or lower. As the solvent, it is particularly preferable to use a solvent having at least one hydroxyl group (for example, alcohol).

  The amount of the solvent is arbitrarily set, but 0.5 parts by mass or more and 30 parts by mass or less, and preferably 1 part by mass or more and 20 parts by mass or less with respect to 1 part by mass of at least one kind selected from a guanamine compound and a melamine compound. Used in.

  In addition, when the coating liquid is obtained by reacting the above components, it may be simply mixed and dissolved, but it is room temperature (for example, 25 ° C.) to 100 ° C., preferably 30 ° C. to 80 ° C. for 10 minutes to 100 hours. Hereinafter, it may be heated for 1 hour to 50 hours. It is also desirable to irradiate ultrasonic waves at this time.

  Then, the coating solution for the surface protective layer is applied on the charge transport layer 2B by a usual method such as blade coating method, Mayer bar coating method, spray coating method, dip coating method, bead coating method, air knife coating method, curtain coating method, etc. The surface protective layer 5 can be obtained by applying the resin by a method and curing it by heating, for example, at a temperature of 100 ° C. or higher and 170 ° C. or lower as necessary.

  The film thickness of the surface protective layer 5 is desirably 1 μm or more and 15 μm or less, and more desirably 3 μm or more and 10 μm or less.

<Process cartridge and image forming apparatus>
Next, a process cartridge and an image forming apparatus using the electrophotographic photosensitive member of this embodiment will be described.
The process cartridge of this embodiment is not particularly limited as long as it uses the electrophotographic photosensitive member of this embodiment. Specifically, the process cartridge is obtained by developing an electrostatic latent image on the surface of the latent image holding member. The electrophotographic photosensitive member according to the present embodiment as the latent image holding member is detachable from an image forming apparatus that transfers the toner image to a recording medium and forms an image on the recording medium. And at least one selected from a charging device, a developing device, and a cleaning device.

  Further, the image forming apparatus of the present embodiment is not particularly limited as long as it uses the electrophotographic photosensitive member of the present embodiment. Specifically, the electrophotographic photosensitive member according to the present embodiment and the electrophotographic photosensitive member are described. A charging device for charging the photosensitive member, a latent image forming device for forming an electrostatic latent image on the surface of the charged electrophotographic photosensitive member, and an electrostatic latent image formed on the surface of the electrophotographic photosensitive member with toner. It is desirable to have a developing device that develops a toner image and a transfer device that transfers the toner image formed on the surface of the electrophotographic photosensitive member to a recording medium. The image forming apparatus of the present embodiment may be a so-called tandem machine having a plurality of photoreceptors corresponding to the toners of the respective colors. In this case, all the photoreceptors are the electrophotographic photoreceptors of the embodiment. Is desirable. The toner image may be transferred by an intermediate transfer system using an intermediate transfer member.

  FIG. 2 is a schematic configuration diagram illustrating the image forming apparatus according to the present embodiment. The image forming apparatus 100 is as shown in FIG. A process cartridge 300 including the electrophotographic photosensitive member 7, an exposure device 9, a transfer device 40, and an intermediate transfer member 50 are provided. 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.

  A process cartridge 300 in FIG. 2 integrally supports an electrophotographic photosensitive member 7, a charging device 8, a developing device 11, and a cleaning device 13 in a housing. The cleaning device 13 has a cleaning blade (cleaning member), and the cleaning blade 131 is disposed so as to contact the surface of the electrophotographic photosensitive member 7.

  In addition, an example is shown in which a fibrous member 132 (roll shape) that supplies the lubricant 14 to the surface of the photoreceptor 7 and a fibrous member 133 (flat brush shape) that assists in cleaning are used. However, it may not be used.

  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, the contact charger is not limited, and as in the image forming apparatus 110 shown in FIG. 3, a non-contact charger 18 (such as a scorotron charger or a corotron charger) using corona discharge, or a non-contact type charger. Known chargers such as roller chargers are also used.

  Although not shown, a photosensitive member heating member for raising the temperature of the electrophotographic photosensitive member 7 and reducing the relative temperature may be provided around the electrophotographic photosensitive member 7.

  Examples of the exposure device 9 include optical system devices that expose the surface of the 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 in the spectral sensitivity region of the photoreceptor. 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 in the vicinity of 400 nm to 450 nm as a blue laser may be used. A surface-emitting laser light source that can output a multi-beam is also effective for color image formation.

  As the developing device 11, for example, a general developing device that performs development by bringing a magnetic or non-magnetic one-component developer or two-component developer into contact or non-contact with each other may be used. The developing device 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 adhering the one-component developer or the two-component developer to the photoreceptor 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 desirable.

Hereinafter, the toner used in the developing device 11 will be described.
The toner used in the image forming apparatus of this embodiment has an average shape factor ((ML ² / A) × (π / 4) × 100, where ML represents the maximum length of the particles, and A represents the projected area of the particles. Is preferably from 100 to 150, more preferably from 105 to 145, and even more preferably from 110 to 140. Further, the toner preferably has a volume average particle size of 3 μm to 12 μm, and more preferably 3.5 μm to 9 μm.

  The toner is not particularly limited by the production method. For example, a kneading and pulverizing method in which a binder resin, a colorant and a release agent, and a charge control agent are further added, kneaded, pulverized, and classified; A method of changing the shape of particles obtained by the method by mechanical impact force or thermal energy; a dispersion monomer formed by emulsion polymerization of a polymerizable monomer of a binder resin, a colorant and a release agent In addition, an emulsion polymerization aggregation method for obtaining toner particles by mixing a dispersion liquid such as a charge control agent and aggregating and heat-fusing to obtain toner particles; a polymerizable monomer for obtaining a binder resin, a colorant and a release agent Suspension polymerization method in which a solution of an agent, a charge control agent, etc. is suspended in an aqueous solvent for polymerization; a binder resin, a coloring agent, a release agent, and a solution of a charge control agent, etc., in an aqueous solvent Toner produced by the suspension method, etc. It is use.

  Further, a known method such as a production method in which the toner obtained by the above method is used as a core, and agglomerated particles are further adhered and heated and fused to give a core-shell structure is used. The toner production method is preferably a suspension polymerization method, an emulsion polymerization aggregation method, or a dissolution suspension method in which an aqueous solvent is used from the viewpoint of shape control and particle size distribution control, and an emulsion polymerization aggregation method is particularly desirable.

  The toner base particles desirably contain a binder resin, a colorant, and a release agent, and may further contain silica or a charge control agent.

  Binder resins used for toner base particles include styrenes such as styrene and chlorostyrene, monoolefins such as ethylene, propylene, butylene and isoprene, vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate, etc. Α-methylene aliphatics such as vinyl esters, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate Homopolymers and copolymers of monocarboxylic acid esters, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl butyl ether, vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropenyl ketone , Polyester resins by copolymerization of dicarboxylic acids and diols.

  Particularly representative binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer. A polymer, polyethylene, a polypropylene, a polyester resin etc. are mentioned. Further, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin wax and the like can be mentioned.

  In addition, as colorants, magnetic powders such as magnetite and ferrite, carbon black, aniline blue, caryl blue, chrome yellow, ultramarine blue, Dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, Lamp Black, Rose Bengal, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 17, C.I. I. Pigment blue 15: 1, C.I. I. Pigment Blue 15: 3 is exemplified as a representative example.

  Typical examples of the release agent include low molecular weight polyethylene, low molecular weight polypropylene, Fischer tropical wax, montan wax, carnauba wax, rice wax, and candelilla wax.

  As the charge control agent, known ones are used, and azo metal complex compounds, metal complex compounds of salicylic acid, and resin type charge control agents containing polar groups are used. When toner is manufactured by a wet manufacturing method, it is desirable to use a material that is difficult to dissolve in water. The toner may be either a magnetic toner containing a magnetic material or a non-magnetic toner containing no magnetic material.

  The toner used in the developing device 11 is manufactured by mixing the toner base particles and the external additive with a Henschel mixer or a V blender. Further, when the toner base particles are produced by a wet method, they may be externally added by a wet method.

  Lubricating particles may be added to the toner used in the developing device 11. Lubricating particles include solid lubricants such as graphite, molybdenum disulfide, talc, fatty acids and fatty acid metal salts, low molecular weight polyolefins such as polypropylene, polyethylene and polybutene, silicones having a softening point upon heating, oleic amides , Erucic acid amide, ricinoleic acid amide, stearic acid amide and other aliphatic amides, carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil and other plant waxes, beeswax animal wax, montan wax, ozokerite , Ceresin, paraffin wax, microcrystalline wax, minerals such as Fischer-Tropsch wax, petroleum wax, and modified products thereof. These are used individually by 1 type or in combination of 2 or more types. However, the average particle size is preferably in the range of 0.1 μm or more and 10 μm or less, and those having the above chemical structure may be pulverized to make the particle sizes uniform. The amount added to the toner is desirably in the range of 0.05% by mass to 2.0% by mass, and more desirably in the range of 0.1% by mass to 1.5% by mass.

  To the toner used in the developing device 11, inorganic particles, organic particles, composite particles obtained by attaching inorganic particles to the organic particles, or the like may be added.

  Inorganic particles include silica, alumina, titania, zirconia, barium titanate, aluminum titanate, strontium titanate, magnesium titanate, zinc oxide, chromium oxide, cerium oxide, antimony oxide, tungsten oxide, tin oxide, tellurium oxide, Various inorganic oxides such as manganese oxide, boron oxide, silicon carbide, boron carbide, titanium carbide, silicon nitride, titanium nitride, and boron nitride, nitrides, borides, and the like are preferably used.

  In addition, the inorganic particles may be mixed with titanium coupling agents such as tetrabutyl titanate, tetraoctyl titanate, isopropyl triisostearoyl titanate, isopropyl tridecylbenzenesulfonyl titanate, bis (dioctylpyrophosphate) oxyacetate titanate, γ- (2- Aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl) γ-aminopropyltrimethoxy Silane hydrochloride, hexamethyldisilazane, methyltrimethoxysilane, butyltrimethoxysilane, isobutyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane The treatment may be performed with a silane coupling agent such as run, decyltrimethoxysilane, dodecyltrimethoxysilane, phenyltrimethoxysilane, o-methylphenyltrimethoxysilane, and p-methylphenyltrimethoxysilane. In addition, those hydrophobized with higher fatty acid metal salts such as silicone oil, aluminum stearate, zinc stearate, calcium stearate and the like are also desirably used.

  Examples of the organic particles include styrene resin particles, styrene acrylic resin particles, polyester resin particles, and urethane resin particles.

  The particle diameter is preferably 5 nm to 1000 nm, more preferably 5 nm to 800 nm, and even more preferably 5 nm to 700 nm in terms of number average particle diameter. Moreover, it is desirable that the sum of the addition amounts of the above-described particles and the lubricating particles is 0.6% by mass or more.

  As the other inorganic oxide added to the toner, it is desirable to use a small-diameter inorganic oxide having a primary particle size of 40 nm or less, and further add an inorganic oxide having a larger diameter. Known inorganic oxide particles are used, but it is desirable to use silica and titanium oxide in combination.

  Moreover, you may surface-treat about a small diameter inorganic particle. Furthermore, it is also desirable to add carbonates such as calcium carbonate and magnesium carbonate and inorganic minerals such as hydrotalcite.

  In addition, the color toner for electrophotography is used by mixing with a carrier. As the carrier, iron powder, glass beads, ferrite powder, nickel powder, or those coated with a resin are used. The mixing ratio with the carrier is set as necessary.

  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.

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

  In addition to the above-described devices, the image forming apparatus 100 may include, for example, a light neutralizing device that performs light neutralization on the photoconductor 7.

  FIG. 4 is a schematic cross-sectional view showing an image forming apparatus according to another embodiment. As shown in FIG. 4, the image forming apparatus 120 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.

  In the image forming apparatus (process cartridge) according to the present embodiment, the developing device is a developing roller that is a developer holder that moves (rotates) in the opposite direction to the moving direction (rotating direction) of the electrophotographic photosensitive member. You may have. Here, the developing roller has a cylindrical developing sleeve that holds developer on the surface, and the developing device has a configuration that includes a regulating member that regulates the amount of developer supplied to the developing sleeve. Can be mentioned. By moving (rotating) the developing roller of the developing device in a direction opposite to the rotation direction of the electrophotographic photosensitive member, the surface of the electrophotographic photosensitive member is rubbed with toner remaining between the developing roller and the electrophotographic photosensitive member. The

  In the image forming apparatus according to the present exemplary embodiment, the distance between the developing sleeve and the photosensitive member is desirably 200 μm or more and 600 μm or less, and more desirably 300 μm or more and 500 μm or less. In addition, the distance between the developing sleeve and the regulating blade, which is a regulating member that regulates the developer amount, is desirably 300 μm or more and 1000 μm or less, and more desirably 400 μm or more and 750 μm or less.

  Further, it is desirable that the absolute value of the moving speed of the developing roll surface is 1.5 times or more and 2.5 times or less of the absolute value (process speed) of the moving speed of the photosensitive member surface. It is more desirable to make it 0 times or less.

  Further, in the image forming apparatus (process cartridge) according to the present embodiment, the developing device (developing unit) includes a developer holding body having a magnetic material, and is a two-component developer containing a magnetic carrier and toner. It is desirable to develop an image.

  In the image forming apparatus according to this embodiment, the process speed, that is, the moving speed of the outer peripheral surface of the electrophotographic photosensitive member is preferably a high speed of 500 mm / s or more.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example and a comparative example, this invention is not limited to a following example at all. In the following, “part” is based on mass unless otherwise specified.

<Preparation of base photoconductor>
[Underlying Photoconductor A]
-Undercoat layer 100 parts of zinc oxide (average particle diameter 70 nm: manufactured by Teika: specific surface area value 15 m ² / g) is stirred and mixed with 500 parts of toluene, and a silane coupling agent (KBM603: manufactured by Shin-Etsu Chemical Co., Ltd.) 1.25 Part was added and stirred for 2 hours. Thereafter, toluene was distilled off under reduced pressure, baking was performed at 120 ° C. for 3 hours, and surface treatment was performed on zinc oxide with a silane coupling agent.
100 parts of the surface-treated zinc oxide was stirred and mixed with 500 parts of tetrahydrofuran, a solution prepared by dissolving 1 part of alizarin in 50 parts of tetrahydrofuran was added, and the mixture was stirred at 50 ° C. for 5 hours. Thereafter, zinc oxide to which alizarin was imparted by filtration under reduced pressure was filtered off, and further dried at 60 ° C. under reduced pressure to obtain an alizarin-given zinc oxide pigment.
60 parts of this alizarin-provided zinc oxide pigment, 13.5 parts of hardener-blocked isocyanate (Sumijoule 3175, manufactured by Sumitomo Bayern Urethane Co., Ltd.) and 15 parts of butyral resin (ESLEC BM-1, manufactured by Sekisui Chemical Co., Ltd.) in 85 parts of methyl ethyl ketone 38 parts of the dissolved solution and 25 parts of methyl ethyl ketone were mixed and dispersed in a sand mill for 2 hours using glass beads having a diameter of 1 mm to obtain a dispersion.
As a catalyst, 0.005 part of dioctyltin dilaurate and 40 parts of silicone resin particles (Tospearl 145, manufactured by GE Toshiba Silicone) are added to the resulting dispersion, followed by drying and curing at 170 ° C. for 40 minutes. A liquid was obtained. This undercoat layer coating solution was dip-coated on an aluminum substrate having a diameter of 84 mm, a length of 347 mm, and a thickness of 1 mm by a dip coating method to obtain an undercoat layer having a thickness of 21 μm.

-Charge generation layer Next, as a charge generation substance, a diffraction peak having a Bragg angle (2θ ± 0.2 °) of 7.4 °, 16.6 °, 25.5 °, 28.3 ° in an X-ray diffraction spectrum is strong. 1 part of a chlorogallium phthalocyanine crystal having a styrene content is added to 100 parts of butyl acetate together with 1 part of polyvinyl butyral resin (trade name: ESREC BM-S, manufactured by Sekisui Chemical Co., Ltd.). Thus, a charge generation layer coating solution was obtained. This charge generation layer coating solution was dip coated on the surface of the undercoat layer and dried by heating at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.2 μm.

Charge transport layer 2 parts of charge transport material 1 (first charge transport material) represented by the following formula, 3 parts of a polymer compound (viscosity average molecular weight: 39,000) represented by the following structural formula 1 and 10 parts of tetrahydrofuran And it melt | dissolved in 5 parts of toluene, and obtained the coating liquid for charge transport layers. This charge transport layer coating solution is dip coated on the surface of the charge generation layer and dried by heating at 135 ° C. for 35 minutes to form a charge transport layer having a thickness of 22 μm. .

[Underlying Photoconductor B]
In the formation of the charge transport layer of the underlying photoreceptor A, instead of 2 parts of the charge transport material A1 (first charge transport material), 2 parts of the charge transport material A2 (first charge transport material) shown below and the charge Except for using 2 parts of the transport material B1: a photoconductor was obtained by the method described for the base photoconductor A, and this photoconductor was used as the base photoconductor B.

[Underlying Photoconductor C]
In the formation of the charge transport layer of the underlying photoreceptor A, instead of 2 parts of the charge transport material A1 (first charge transport material), 1 part of the charge transport material A2 (first charge transport material) described above and the charge transport material B1: A photoconductor was obtained by the method described in Background Photoconductor A except that 3 parts were used, and this photoconductor was designated as Base Photoconductor C.

[Underlying photoreceptor D]
Except for using the charge transport material B2 (first charge transport material) shown below instead of the charge transport material A1 (first charge transport material) in the formation of the charge transport layer of the underlying photoreceptor A, A photoconductor was obtained by the method described in Base Photoconductor A, and this photoconductor was designated as Base Photoconductor D.

[Underlying photoreceptor E]
In the formation of the charge transport layer of the underlying photoconductor A, the underlying photosensitivity is except that the above-described charge transport material B1 (first charge transport material) is used instead of the charge transport material A1 (first charge transport material). A photoconductor was obtained by the method described in the photoconductor A, and this photoconductor was used as a base photoconductor E.

[Underlying photoreceptor F]
In the formation of the charge transport layer of the underlying photoreceptor A, a charge transport material B3 (first charge transport material) shown below was used instead of the charge transport material A1 (first charge transport material), A photoconductor was obtained by the method described in Base Photoconductor A, and this photoconductor was designated as Base Photoconductor F.

[Example 1]
[Photoreceptor 1]
Charge transport material C1 (second charge transport material) represented by the following formula: 94 parts, and 5 parts of benzoguanamine resin (Nicarac BL-60, manufactured by Sanwa Chemical Co., Ltd.) are added to 240 parts of cyclopentanone. After dissolution and mixing, 0.9 part of dimethylpolysiloxane (Granol 450, manufactured by Kyoeisha Chemical Co., Ltd.) and 0.1 part of NACURE 5225 (manufactured by King Industry Co., Ltd.) were added to prepare a coating solution for forming a surface protective layer. This surface protective layer coating solution is applied onto the above-mentioned underlying photoreceptor A by dip coating and dried at 155 ° C. for 40 minutes to form a surface protective layer having a thickness of 6 μm. It was.

[Example 2]
[Photoreceptor 2]
4 parts of Lubron L-2 (manufactured by Daikin Industries, Ltd.) as tetrafluoroethylene resin particles and a fluorinated alkyl group-containing copolymer containing a repeating unit represented by the following structural formula 2 (weight average molecular weight 50,000, l : M = 1: 1, s = 1, n = 60) 0.2 part of was sufficiently stirred and mixed with 16 parts of cyclopentanone to prepare a tetrafluoroethylene resin particle suspension.

Next, after adding 94 parts of the above-described charge transport material C1 (second charge transport material) and 1 part of benzoguanamine resin to 220 parts of cyclopentanone and sufficiently dissolving and mixing them, the tetrafluoroethylene resin particle suspension is added. Dispersion treatment by adding pressure to 700 kgf / cm ² using a high-pressure homogenizer (YSNM-1500AR, manufactured by Yoshida Kikai Kogyo Co., Ltd.) equipped with a penetrating chamber with fine flow paths after adding turbid liquid and stirring 30 times Repeated. Thereafter, 0.9 part of dimethylpolysiloxane (Granol 450, manufactured by Kyoeisha Chemical Co., Ltd.) and 0.1 part of NACURE 5225 (manufactured by King Industry Co., Ltd.) were added to prepare a coating solution for forming a surface protective layer. This surface protective layer coating solution is applied onto the above-mentioned base photoreceptor A by a dip coating method and dried at 155 ° C. for 40 minutes to form a surface protective layer having a thickness of 6 μm. It was.

Example 3
[Photoreceptor 3]
92 parts of the aforementioned charge transport material C1 (second charge transport material) and 7 parts of methylated melamine resin (B-2: Nicalac MW-30HM, manufactured by Sanwa Chemical Co., Ltd.) are added to 240 parts of cyclopentanone. After sufficiently dissolving and mixing, 0.9 part of dimethylpolysiloxane (Granol 450, manufactured by Kyoeisha Chemical Co., Ltd.) and 0.1 part of NACURE 5225 (manufactured by King Industry Co., Ltd.) were added to prepare a coating solution for forming a surface protective layer. . This surface protective layer coating solution is applied onto the above-mentioned underlying photoreceptor B by dip coating and dried at 155 ° C. for 40 minutes to form a surface protective layer having a thickness of 6 μm. It was.

Example 4
[Photosensitive member 4]
In the formation of the surface protective layer of the photoreceptor 1, the amount of the charge transport material C1 (second charge transport material) is 75 parts, and the amount of the benzoguanamine resin (Nicarac BL-60, manufactured by Sanwa Chemical Co., Ltd.) is 24 parts. A photoconductor was obtained by the method described in Photoconductor 1 except that the photoconductor 4 was used.

Example 5
[Photoreceptor 5]
The aforementioned charge transport material C1 (second charge transport material): 97 parts, and 2 parts of benzoguanamine resin (Nicalac BL-60, manufactured by Sanwa Chemical Co., Ltd.) were added to 240 parts of cyclopentanone and mixed sufficiently. Thereafter, 0.9 part of dimethylpolysiloxane (Granol 450, manufactured by Kyoeisha Chemical Co., Ltd.) and 0.1 part of NACURE 5225 (manufactured by King Industry Co., Ltd.) were added to prepare a coating solution for forming a surface protective layer. This surface protective layer coating solution is applied onto the above-mentioned underlying photoreceptor B by dip coating and dried at 155 ° C. for 40 minutes to form a surface protective layer having a thickness of 6 μm. It was.

Example 6
[Photoreceptor 6]
The aforementioned charge transport material C1 (second charge transport material): 85 parts and methylated melamine resin (B-2: Nicalac MW-30HM) 14 parts were added to 240 parts of cyclopentanone and mixed sufficiently. Thereafter, 0.9 part of dimethylpolysiloxane (Granol 450, manufactured by Kyoeisha Chemical Co., Ltd.) and 0.1 part of NACURE 5225 (manufactured by King Industry Co., Ltd.) were added to prepare a coating solution for forming a surface protective layer. This surface protective layer coating solution is applied onto the above-mentioned underlying photoreceptor B by dip coating and dried at 155 ° C. for 40 minutes to form a surface protective layer having a thickness of 6 μm. It was.

Example 7
[Photoreceptor 7]
Charge transport material C2 (second charge transport material) shown below: 94 parts, 5 parts of benzoguanamine resin (Nicarac BL-60, Sanwa Chemical Co., Ltd.) are added to 240 parts of cyclopentanone and mixed sufficiently. Thereafter, 0.9 part of dimethylpolysiloxane (Granol 450, manufactured by Kyoeisha Chemical Co., Ltd.) and 0.1 part of NACURE 5225 (manufactured by King Industry Co., Ltd.) were added to prepare a coating solution for forming a surface protective layer. This surface protective layer coating solution is applied onto the above-mentioned underlying photoreceptor B by dip coating and dried at 155 ° C. for 40 minutes to form a surface protective layer having a thickness of 6 μm. It was.

Example 8
[Photoreceptor 8]
The charge transport material C2 (second charge transport material) described above: 98 parts, 1 part of a benzoguanamine resin (Nicarac BL-60, manufactured by Sanwa Chemical Co., Ltd.) is added to 240 parts of cyclopentanone and sufficiently mixed. Then, 0.9 part of dimethylpolysiloxane (Granol 450, manufactured by Kyoeisha Chemical Co., Ltd.) and 0.1 part of NACURE 5225 (manufactured by King Industry Co., Ltd.) were added to prepare a coating solution for forming a surface protective layer. This surface protective layer coating solution is applied onto the above-mentioned base photoreceptor C by dip coating, and dried at 155 ° C. for 40 minutes to form a surface protective layer having a film thickness of 6 μm. It was.

Example 9
[Photoreceptor 9]
In preparing the coating solution for the surface protective layer of the photoreceptor 2, a methylated melamine resin was used instead of the benzoguanamine resin. This surface protective layer coating solution is applied onto the above-mentioned underlying photoreceptor B by dip coating and dried at 155 ° C. for 40 minutes to form a surface protective layer having a thickness of 6 μm. It was.

[Comparative Example 1]
[Photosensitive member 10]
In the photoconductor 1, a photoconductor was obtained by the method described in the photoconductor 1 except that the base photoconductor D was used instead of the base photoconductor A, and this was designated as photoconductor 10.

[Comparative Example 2]
[Photoreceptor 11]
In the photoconductor 1, except that the base photoconductor E was used instead of the base photoconductor A, a photoconductor was obtained by the method described in the photoconductor 1, and this was used as the photoconductor 11.

[Comparative Example 3]
[Photoreceptor 12]
In the photoconductor 1, except that the base photoconductor F was used instead of the base photoconductor A, a photoconductor was obtained by the method described in the photoconductor 1, and this was used as the photoconductor 12.

[Comparative Example 4]
[Photoreceptor 13]
In the photoconductor 7, except that the base photoconductor F was used instead of the base photoconductor B, a photoconductor was obtained by the method described in the photoconductor 7 and this was used as the photoconductor 13.

[Comparative Example 5]
[Photoreceptor 14]
4 parts of Lubron L-2 (manufactured by Daikin Industries) as tetrafluoroethylene resin particles and a fluorinated alkyl group-containing copolymer containing a repeating unit represented by the above structural formula 2 (weight average molecular weight 50,000, l : M = 1: 1, s = 1, n = 60) 0.2 part of was sufficiently stirred and mixed with 16 parts of cyclopentanone to prepare a tetrafluoroethylene resin particle suspension.
Next, 70 parts of the aforementioned charge transport material C1 (second charge transport material): 25 parts of benzoguanamine resin are added to 220 parts of cyclopentanone, and after sufficiently dissolving and mixing, the tetrafluoroethylene resin particle suspension is added. Dispersion treatment by adding pressure to 700 kgf / cm ² using a high-pressure homogenizer (YSNM-1500AR, manufactured by Yoshida Kikai Kogyo Co., Ltd.) equipped with a penetrating chamber with fine flow paths after adding turbid liquid and stirring 30 times Repeated. Thereafter, 0.9 part of dimethylpolysiloxane (Granol 450, manufactured by Kyoeisha Chemical Co., Ltd.) and 0.1 part of NACURE 5225 (manufactured by King Industry Co., Ltd.) were added to prepare a coating solution for forming a surface protective layer. This surface protective layer coating solution is applied by dip coating onto the above-mentioned underlying photoreceptor A and dried at 155 ° C. for 40 minutes to form a surface protective layer having a thickness of 6 μm. It was.

[Comparative Example 6]
[Underlying photoreceptor G]
Up to the charge generation layer was prepared by the method described in the above-mentioned underlying photoconductor A.
Next, 7 parts of charge transport material B4 (first charge transport material) shown below, 10 parts of polycarbonate resin (Panlite TS-2050, manufactured by Teijin Chemicals Ltd.), 79 parts of tetrahydrofuran and 1% silicone oil (KF50- 100CS, manufactured by Shin-Etsu Chemical Co., Ltd.) was dissolved in 1 part of a tetrahydrofuran solution to obtain a coating solution for a charge transport layer. This charge transport layer coating solution is dip coated on the surface of the charge generation layer and dried by heating at 120 ° C. for 30 minutes to form a charge transport layer having a thickness of 22 μm. .

[Photoreceptor 15]
Next, charge transport material C3 (second charge transport material) shown below: 3 parts, and 12 parts of melamine resin (Super Becamine L-145-60, manufactured by Dainippon Ink & Chemicals, Inc.), thermosetting interface 2 parts of an activator (hydrophobic resin ZX-007C, manufactured by Fuji Kasei Kogyo Co., Ltd.) was added to 190 parts of tetrahydrofuran and 53 parts of cyclohexanone and sufficiently dissolved and mixed to prepare a coating solution for forming a surface protective layer. This surface protective layer coating solution is applied onto the above-mentioned underlying photoconductor G by spray coating and dried at 170 ° C. for 30 minutes to form a surface protective layer having a thickness of 3 μm. It was.

<Measurement of physical properties>
Charge generation material ionization potential (Ip (CGL)), first charge transport material ionization potential (Ip (CTL)), second charge transport material ionization potential (Ip (OCL)), hole in charge transport layer The mobility (electric field strength 30 V / μm) (μ (CTL)) and the hole mobility (electric field strength 30 V / μm) (μ (OCL)) of the surface protective layer were measured by the above-described method, and | Ip (CTL) − The values of Ip (CGL) |, | Ip (OCL) −Ip (CTL) |, μ (CTL) / μ (OCL) were calculated. The results are shown in Table 1.

<Evaluation test>
-Image formation test-
An image formation test was performed using the photoreceptors 1 to 11. The experimental machines were DocuCollar 8000AP Digital Press manufactured by Fuji Xerox Co., Ltd., with a printing speed of 80 sheets / minute (the movement speed of the outer surface of the electrophotographic photosensitive member is 440 mm / s) and 120 sheets / minute (the movement speed of the outer surface of the electrophotographic photosensitive member). Is modified so that it can output at 660 mm / s).
In the test, first, the initial image quality (ghost evaluation / halftone shown in [1] and [2] below) was evaluated in a multi-color color under an environment of 22 ° C. and 55% RH. Thereafter, 100,000 images of A4 paper size with an image density of 5% were formed (running), and after running (after the run), the image quality (ghost evaluation / halftone shown in [1] and [2] below) Evaluation, [3] Evaluation of the photoreceptor residual potential, and [4] Evaluation of wear amount per 1000 revolutions (nm) were performed.
Running is performed at a print speed of 80 sheets / minute. When evaluating the initial image quality and the post-running image quality, both normal speed (80 sheets / minute) and high speed (120 sheets / minute) are used. Evaluation was performed.

[1] Ghost evaluation (normal speed: 80 sheets / min)
As shown in FIG. 5 (A), the ghost evaluation prints a chart of a pattern having a letter “G” and a “black solid area”, and determines the appearance of the letter “G” (ghost) in the black solid area. Observed visually and evaluated according to the following criteria: As shown in FIG. 5A, the letter “G” is not confirmed in the black solid region.
Δ: As shown in FIG. 5B, the letter “G” is slightly confirmed in the black solid region.
X: As shown in FIG. 5C, the letter “G” is clearly confirmed in the black solid region.

[2] Ghost evaluation (high speed: 120 sheets / min)
Evaluation similar to the above [1] ghost evaluation was performed on an image output at a printing speed of 120 sheets / min.
A: As shown in FIG. 5A, the letter “G” is not confirmed in the black solid region.
Δ: As shown in FIG. 5B, the letter “G” is slightly confirmed in the black solid region.
X: As shown in FIG. 5C, the letter “G” is clearly confirmed in the black solid region.

[3] Photoresist Residual Potential The photoconductor residual potential is measured by attaching a potential probe to the experimental machine and measuring the residual potential (photoconductor potential after completion of image formation) between the initial stage and after running. Was calculated.
○: The difference is less than 38V Δ: The difference is 38V or more and less than 60V ×: The difference is 60V or more

[4] Wear amount The wear amount is measured by measuring the film thickness before image formation in advance and measuring the difference from the film thickness after running to determine the wear amount per 1000 rotations of the photoreceptor. The amount (nm) was calculated.
○: 3 nm / kcyc or less Δ: Over 3 nm / kcyc and less than 5 nm / kcyc ×: 5 nm / kcyc or more

[5] Evaluation Criteria for Comprehensive Judgment Based on the evaluation results of ghost evaluation (normal speed), ghost evaluation (high speed), photoconductor residual potential, and wear amount, comprehensive evaluation was performed according to the following criteria.
○: Good (up to 2 △)
△: Slightly inferior, but no problem (up to 3 △)
×: Unusable (more than 4 △ or more than 1)

  As shown in Table 2, it can be seen that, in this example, compared with the comparative example, excellent electrical resistance and high image quality are maintained over a long period of time while maintaining excellent wear resistance and excellent high-speed response.

DESCRIPTION OF SYMBOLS 1 Substrate, 2 Photosensitive layer, 2A Charge generation layer, 2B Charge transport layer, 4 Undercoat layer, 5 Surface protective layer, 7 Photoconductor, 8 Charging device, 9 Exposure device, 11 Developing device, 13 Cleaning device, 14 Lubricant , 18 Non-contact type charger, 40 transfer device, 50 intermediate transfer member, 100, 110, 120 image forming device, 131 cleaning blade, 132 fibrous member, 133 fibrous member, 300 process cartridge

Claims (7)

On the substrate, a charge generation layer containing at least a charge generation material, a charge transport layer containing a first charge transport material, and a surface protective layer containing a second charge transport material in this order, An electrophotographic photosensitive member satisfying the following formulas (1) to (3).
Formula (1) | Ip (CTL) −Ip (CGL) | ≦ 0.1 (eV)
Formula (2) | Ip (OCL) −Ip (CTL) | ≦ 0.3 (eV)
Formula (3) μ (CTL) ≧ 1.8 × 10 ⁻⁵ [cm ² / Vs]
(In Formulas (1) to (3), Ip (CGL) is the ionization potential of the charge generation material, Ip (CTL) is the ionization potential of the first charge transport material, and Ip (OCL) is the first potential. (2) The ionization potential of the charge transport material 2 and μ (CTL) represents the hole mobility of the charge transport layer at an electric field strength of 30 V / μm. The electrophotographic photosensitive member according to claim 1, wherein the formula (2) satisfies the following formula (2 ′), the formula (3) satisfies the following formula (3 ′), and further satisfies the following formula (4).
Formula (2 ′) | Ip (OCL) −Ip (CTL) | ≦ 0.2 (eV)
Formula (3 ′) μ (CTL) ≧ 2.5 × 10 ⁻⁵ [cm ² / Vs]
Formula (4) 0.5 ≦ μ (CTL) / μ (OCL) ≦ 5
(In Formula (2 ′), Formula (3 ′) and Formula (4), Ip (CTL) is the ionization potential of the first charge transport material, and Ip (OCL) is the ionization potential of the second charge transport material. The potential, μ (CTL) represents the hole mobility of the charge transport layer at an electric field strength of 30 V / μm, and μ (OCL) represents the hole mobility of the surface protective layer at an electric field strength of 30 V / μm.) The electrophotographic photosensitive member according to claim 1, wherein the first charge transport material is represented by the following (general formula 1) or (general formula 2).

(In the above (general formula 1), R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ , R ³⁶ may be the same or different and each represents a hydrogen atom, an alkyl group, an alkoxy group, a phenoxy group. Represents a halogen atom or an aryl group which may have a substituent, and m and n represent 0 or 1.)


(In the above (general formula 2), R ³⁷ , R ³⁸ , R ³⁹ , R ⁴⁰ , R ⁴¹ , R ⁴² , R ⁴³ may be the same or different, and each represents a hydrogen atom, an alkyl group, or an alkoxy group. , A phenoxy group, a halogen atom, or an aryl group which may have a substituent, m and n each represents 0 or 1)   The electrophotographic photosensitive member according to claim 1, wherein the surface protective layer contains a crosslinked product of a composition containing fluorine-based resin particles. On the substrate, a charge generation layer containing at least a charge generation material, a charge transport layer containing a first charge transport material, and a surface protective layer containing a second charge transport material in this order, And an electrophotographic photoreceptor satisfying the following formulas (1) to (3):
And a charging device for charging the electrophotographic photosensitive member, a latent image forming device for forming an electrostatic latent image on the surface of the charged electrophotographic photosensitive member, and an electrostatic latent image formed on the surface of the electrophotographic photosensitive member. Select from a developing device that forms a toner image by developing with toner, a transfer device that transfers a toner image formed on the surface of the electrophotographic photosensitive member to a recording medium, and a cleaning device that cleans the surface of the electrophotographic photosensitive member A process cartridge comprising at least one of the following.
Formula (1) | Ip (CTL) −Ip (CGL) | ≦ 0.1 (eV)
Formula (2) | Ip (OCL) −Ip (CTL) | ≦ 0.3 (eV)
Formula (3) μ (CTL) ≧ 1.8 × 10 ⁻⁵ [cm ² / Vs]
(In Formulas (1) to (3), Ip (CGL) is the ionization potential of the charge generation material, Ip (CTL) is the ionization potential of the first charge transport material, and Ip (OCL) is the first potential. (2) The ionization potential of the charge transport material 2 and μ (CTL) represents the hole mobility of the charge transport layer at an electric field strength of 30 V / μm. On the substrate, a charge generation layer containing at least a charge generation material, a charge transport layer containing a first charge transport material, and a surface protective layer containing a second charge transport material in this order, And an electrophotographic photosensitive member satisfying the following formulas (1) to (3):
A charging device for charging the electrophotographic photosensitive member,
A latent image forming apparatus for forming an electrostatic latent image on the surface of the charged electrophotographic photosensitive member;
A developing device for developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive member with toner to form a toner image;
And a transfer device for transferring a toner image formed on the surface of the electrophotographic photosensitive member to a recording medium,
An image forming apparatus.
Formula (1) | Ip (CTL) −Ip (CGL) | ≦ 0.1 (eV)
Formula (2) | Ip (OCL) −Ip (CTL) | ≦ 0.3 (eV)
Formula (3) μ (CTL) ≧ 1.8 × 10 ⁻⁵ [cm ² / Vs]
(In Formulas (1) to (3), Ip (CGL) is the ionization potential of the charge generation material, Ip (CTL) is the ionization potential of the first charge transport material, and Ip (OCL) is the first potential. (2) The ionization potential of the charge transport material 2 and μ (CTL) represents the hole mobility of the charge transport layer at an electric field strength of 30 V / μm.   The image forming apparatus according to claim 6, wherein a moving speed of the outer peripheral surface of the electrophotographic photosensitive member is 500 mm / s or more.