JP2002040677A - Electrophotographic photoreceptor used for device for image formation by wet development method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor, having superior resistance against Isopar (R), such that when the photoreceptor is immersed in Isopar, the appearance of the photoreceptor surface does not change and elution of the charge transfer agent in the Isopar is very small. SOLUTION: The photoreceptor has a photosensitive layer, consisting of a binder resin containing a charge generating agent and a charge transfer agent on a conductive substrate. The binder resin contains polyester resin which is substantially a linear polymer, containing at least one kind of dihydroxy compound expressed by general formula [1], [2] or [3] as a diol component and containing at least naphthalene dicarboxylic expressed by general formula [4] as an acid component. The photoreceptor is used for a device for image formation by wet development method using a developer solution containing toner particles dispersed in Isopar solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member used for an image forming apparatus such as an electrophotographic copying machine, a facsimile, and a laser beam printer. More specifically, the present invention relates to an organic photoreceptor that can be used in an image forming apparatus using a wet development method.

[0002]

2. Description of the Related Art Electrophotographic developing systems utilizing the Carlson process are broadly classified into dry developing systems and wet developing systems. An image forming apparatus using a dry developing method is widely and generally used at present, such as a copying machine and a printer.However, although an image forming apparatus using a wet developing method has been developed for a long time, At present, it is used only in special fields.

[0003] However, in an image forming apparatus using a wet developing method, a toner is generally dispersed in a hydrocarbon-based solvent called isoper, and the toner particle diameter is 1 μm.
m, the resulting image has very high image quality. For this reason, with the recent expansion of the market of full-color printers that require high image quality, they have been spotlighted again.

An image forming apparatus using a wet developing method is
As described above, since a solvent called isoper is used as a developing solution, all or a part of the photosensitive drum is immersed in the solvent. For this reason, an inorganic photoreceptor such as selenium or amorphous silicon, which does not elute the photoreceptor component in the isopar, is generally used.

On the other hand, the organic photoreceptor is easier to manufacture and lower in cost than the conventional inorganic photoreceptor, and has a charge transport agent,
In recent years, photoreceptor materials such as a charge generating agent and a binder resin are widely used because they have various options and a high degree of freedom in functional design.

[0006] The organic photoreceptor includes a single-layer type photoreceptor in which a charge transporting agent (hole transporting agent, electron transporting agent) is dispersed in the same photosensitive layer together with a charge generating agent, and a charge generating agent containing a charge generating agent. There is a laminated photoconductor in which a layer and a charge transport layer containing a charge transport agent are laminated.

[0007] In particular, the single-layer type photoreceptor has been spotlighted because it has a simple structure and is easy to manufacture, it can suppress film defects when forming layers, has few interfaces between layers, and can improve optical characteristics. Is taking a bath.

[0008] The lamination type photoreceptor and the single layer type photoreceptor can be used for both positive and negative charging types.
In general, due to the characteristics of the photoconductor constituent materials,
The mainstream is to use a negative charge for the laminated type and a positive charge for the single layer type.

For this reason, inorganic photoreceptors such as selenium and amorphous silicon generally used in an image forming apparatus utilizing the above-mentioned wet developing method are usually positively charged, and therefore, the inorganic photoreceptors conventionally used have been used. When the body is replaced with an inexpensive organic photoreceptor, the single-layer type organic photoreceptor is advantageous because it is the same positively charged type.

[00010]

SUMMARY OF THE INVENTION A general organic photoreceptor is
When used in an image forming apparatus using a wet development method,
As described above, since all or a part of the photoconductor drum is immersed in the isopar, an external appearance change such as a crack occurs on the photoconductor surface, and a charge transport agent (a hole transport agent or an electron transport agent) or the like is generated. Low molecular weight substances elute into Isopar,
Phenomena such as a decrease in charging and a decrease in sensitivity occur, making it difficult to obtain a good image.

Therefore, by using an organic photoreceptor in which the surface of the organic photoreceptor is further overcoated (surface protective layer) with a thermosetting resin such as a silicone resin, a melamine resin, or an epoxy resin, isoper resistance is exhibited. However, it has been proposed to prevent the elution of the charge transport agent. However, applying the overcoat remarkably degrades the sensitivity and increases the production cost.

On the other hand, as a method of not applying an overcoat, a charge transporting property is imparted to the binder resin itself (a charge transporting polymer), and the content of the charge transporting agent is reduced to zero or reduced, thereby exhibiting the isopar resistance. However, the molecular design of the charge transport polymer is very difficult, and is far from practical sensitivity as an electrophotographic photoreceptor.

Therefore, an object of the present invention is to provide a photoreceptor surface that has no change in appearance even when immersed in an isoper without overcoating and has excellent isoper resistance (the charge transport agent is extremely eluted into the isoper). It is an object of the present invention to provide an electrophotographic photoreceptor having low sensitivity and having practical sensitivity.

[0014]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that, in order to attain the above object, a photosensitive resin comprising at least a charge generating agent and a binder resin containing a charge transporting agent on a conductive substrate. Comprising a layer, wherein the binder resin is
A diol component represented by the general formula [1], [2] or [3]
Containing at least one dihydroxy compound represented by the formula (I), and containing a naphthalenedicarboxylic acid represented by the general formula [4] as an acid component, and a polyester resin which is a substantially linear polymer. Even when the photoreceptor is used in an image forming apparatus of a wet development type using a developing solution in which toner particles are dispersed in an isoper-based solvent, it has extremely good isoper resistance and contains a charge transport agent (hole transporter). Agent or electron transporting agent) hardly eluted into the isopar, and a good image was obtained.

General formula [1]:

Embedded image

General formula [2]:

Embedded image

General formula [3]:

Embedded image (In the general formulas [1], [2] and [3], R ¹
Is an alkylene group having 2 to 4 carbon atoms, R ² , R ³ , R ⁴ and R ⁵
Is the same or different and represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aryl group or an aralkyl group. In the general formula [2], n is an integer of 2 or more. In the general formula [3], R ⁶ and R ⁷ are the same or different and each have 1 carbon atom.
And 10 to 10 alkyl groups. )

General formula [4]:

Embedded image [Detailed description of the invention]

[00019]

The electrophotographic photoreceptor of the present invention is used in a wet image forming apparatus using an isoper-based solvent. The electrophotographic photoreceptor comprises at least a charge generating agent and a binder resin containing a charge transporting agent on a conductive substrate. Wherein the binder resin has a general formula [1] or [2] as a diol component.
Or a substantially linear polymer polyester resin containing at least one dihydroxy compound represented by [3] and at least a naphthalenedicarboxylic acid represented by the general formula [4] as an acid component: It is characterized by containing.

The reason for improving the isoper resistance of the electrophotographic photoreceptor of the present invention is that the isoper solvent in which a part or all of the photoreceptor drum is immersed is an aliphatic hydrocarbon solvent and has low polarity. Therefore, it is considered that the use of the binder resin containing the polyester resin having a relatively high polarity reduces the interaction between the photoreceptor surface and the isoper, and makes it difficult for the charge transport agent to elute into the isoper.

Further, the polyester resin has extremely good compatibility with the charge transporting agent, and the molecule of the charge transporting agent is
Since the molecules are uniformly dispersed in the binder resin molecules, the interaction with the binder resin molecules is strong, and it is hard to be eluted into the isopar, which is presumed to contribute to the improvement of the isopar resistance.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The electrophotographic photoreceptor of the present invention is used in a wet image forming apparatus using an isopar-based solvent, and has a photosensitive layer comprising at least a charge generating agent and a binder resin containing a charge transporting agent. The binder resin contains at least one dihydroxy compound represented by the general formula [1], [2] or [3] as a diol component, and contains a naphthalenedicarboxylic acid represented by a general formula [4] as an acid component. Any photoreceptor may be used as long as it contains at least the polyester resin that is a substantially linear polymer, and a single-layer type containing a charge generating agent and a charge transporting agent in a single photosensitive layer. It may be a photoconductor,
It may be a laminated photoconductor in which a charge generation layer and a charge transport layer are laminated.

[Binder Resin] The binder resin used in the electrophotographic photoreceptor of the present invention contains at least one dihydroxy compound represented by the general formula [1], [2] or [3] as a diol component. And a polyester resin which is a substantially linear polymer and contains at least a naphthalenedicarboxylic acid represented by the general formula [4] as an acid component.

The binder resin used in the electrophotographic photoreceptor of the present invention may contain at least the polyester resin described above. In addition, various resins conventionally used for the photosensitive layer may be used. it can.

For example, polycarbonate resins such as bisphenol Z type, bisphenol ZC type, bisphenol C type, bisphenol A type and the like, polyarylate resins, styrene-butadiene copolymers, styrene-acrylonitrile copolymers, styrene-maleic acid copolymers Polymer,
Acrylic copolymer, styrene-acrylic acid copolymer, polyethylene, ethylene-vinyl acetate copolymer, chlorinated polyethylene, polyvinyl chloride, polypropylene, ionomer, vinyl chloride-vinyl acetate copolymer, alkyd resin, polyamide, polyurethane , Polysulfone, diallyl phthalate resin, ketone resin, polyvinyl butyral resin, thermoplastic resin such as polyether resin, silicone resin, epoxy resin, phenol resin, urea resin, melamine resin, other crosslinkable thermosetting resin, epoxy acrylate, Resins such as a photocurable resin such as urethane-acrylate can be used.

The above-mentioned binder resins can be used alone or as a blend or copolymer of two or more.

The weight average molecular weight of the binder resin used in the electrophotographic photosensitive member of the present invention is from 10,000 to 400,
000, more preferably 30,000 to 200,000.

[Charge Generator] Examples of the charge generator used in the electrophotographic photoreceptor of the present invention include phthalocyanine pigments such as metal-free phthalocyanine (PCH ₂ ) and oxotitanyl phthalocyanine (PcTiO), and perylene pigments. , Bisazo pigments, diketopyrrolopyrrole pigments, metal-free naphthalocyanine pigments, metal naphthalocyanine pigments, squaraine pigments, trisazo pigments, indigo pigments, azurenium pigments, cyanine pigments, pyrylium pigments, anthanthrone pigments, triphenylmethane pigments,
Conventionally known charge generators such as organic photoconductors such as sulene pigments, toluidine pigments, pyrazoline pigments, and quinacridone pigments; and inorganic photoconductive materials such as selenium, selenium-tellurium, selenium-arsenic, cadmium sulfide, and amorphous silicon. Is mentioned.

The charge generating agents exemplified above can be used alone or in combination of two or more so as to have an absorption wavelength in a desired region.

Among the above-described charge generating agents, in particular, a digital optical image forming apparatus such as a laser beam printer or a facsimile using a light source such as a semiconductor laser includes:
Since a photoconductor having a sensitivity in a wavelength region of 700 nm or more is required, for example, a metal-free phthalocyanine (PC
H ₂ ), oxotitanyl phthalocyanine (PcTiO)
And the like. Phthalosinine pigments such as The crystal form of the phthalocyanine pigment is not particularly limited, and various types can be used.

In the case of a single-layer type photoreceptor, the charge generating agent is preferably contained in an amount of 0.1 to 50% by weight, more preferably 0.5 to 30% by weight based on the total weight of the binder resin. In the case of a laminated type photoreceptor, 1 to 500 wt%, further 10 to 300 wt%
%.

[Charge Transport Agent] As the charge transport agent used in the electrophotographic photoreceptor of the present invention, a conventionally known electron transport agent or hole transport agent can be used. In particular, in the case of a single-layer type photoreceptor, it is preferable that an electron transporting agent and a hole transporting agent are blended and contained in the photosensitive layer.

Examples of the electron transporting agent usable for the electrophotographic photoreceptor of the present invention include diphenoquinone derivatives, benzoquinone derivatives, anthraquinone derivatives, malononitrile derivatives, thiopyran derivatives, trinitrothioxanthone derivatives, 3,4,5,7- Tetranitro-9-fluorenone derivative, dinitroanthracene derivative, dinitroacridine derivative, nitroantaraquinone derivative, dinitroanthraquinone derivative, tetracyanoethylene,
Various compounds having an electron-accepting property, such as 2,4,8-trinitrothioxanthone, dinitrobenzene, dinitroanthracene, dinitroacridine, nitroanthraquinone, dinitroanthraquinone, succinic anhydride, maleic anhydride, and dibromomaleic anhydride are listed. Can be

In the present invention, only one electron transporting agent may be used, or two or more electron transporting agents may be blended and used.

Examples of the hole transporting agent usable in the electrophotographic photoreceptor of the present invention include N, N, N ', N'-tetraphenylbenzidine derivatives, N, N, N', N'-tetraphenylphenylenediamine Derivatives, N, N, N ',
N′-tetraphenylnaphthylenediamine derivative, N,
N, N ', N'-tetraphenylphenanthrylenediamine derivative, 2,5-di (4-methylaminophenyl)
Oxadiazole compounds such as -1,3,4-oxadiazole, styryl compounds such as 9- (4-diethylaminostyryl) anthracene, carbazole compounds such as polyvinylcarbazole, organic polysilane compounds,
Pyrazoline compounds such as -phenyl-3- (p-dimethylaminophenyl) pyrazoline, hydrazone compounds,
Examples include nitrogen-containing cyclic compounds such as indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, triazole compounds, and condensed polycyclic compounds.

In the present invention, only one type of hole transporting agent may be used, or two or more types may be blended and used.

In general, the higher the charge transporting agent content, the better the photosensitivity of the photoreceptor, but the higher the ratio of the charge transporting agent molecules present near the surface of the photoreceptor. Are easily eluted into the isopar, and the isopar resistance is reduced. Conversely, as the content of the charge transporting agent decreases, the photosensitivity deteriorates, but the isopar resistance improves.
For this reason, it is preferable that the solid content concentration of all the charge transporting agents be 50 wt% or less of the total solid content concentration.

In particular, since the stilbene derivative represented by the general formula [5] has a high mobility as a hole transporting agent, sufficient photosensitivity is exhibited even with a relatively small content.
That is, the solid content concentration of the charge transporting agent containing the hole transporting agent represented by the general formula [5] is set to 50 wt% of the total solid concentration.
% Or less, it is possible to obtain a photoreceptor having very little elution into the isopar and having photosensitivity that does not cause any practical problem.

General formula [5]:

Embedded image (In the general formula [5], R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are the same or different, and are an alkyl group, an alkoxy group, an aryl group,
Represents an aralkyl group or a halogen atom, m, n, p
And q are the same or different and each represents an integer of 0 to 3. R ¹²
And R ¹³ are the same or different and each represent a hydrogen atom or an alkyl group. Also, -X-

Embedded image Or

Embedded image Is shown. )

On the other hand, only in the case of a single layer type photoreceptor, the content of the hole transporting agent is preferably equal to or less than the content of the electron transporting agent. This is because the hole transporting agent and the electron transporting agent often form a charge transporting complex (CT complex), and the CT complex is hardly soluble in the isopar. This is considered to be due to easy elution.

In particular, a compound represented by the general formula [6] is preferably used as an electron transporting agent. This is a combination in which the hole transporting agent represented by the general formula [5] and the electron transporting agent represented by the general formula [6] easily form a CT complex. It is presumed that it is hardly soluble.

General formula [6]:

Embedded image (In the general formula [6], R ¹⁴ represents a halogen atom, an optionally substituted alkyl group or an aryl group, R ¹⁵ represents an optionally substituted alkyl group or an aryl group,
Or a group: -OR ^15a . R ^15a represents an alkyl group or an aryl group which may have a substituent. )

In the case of a single-layer type photosensitive member, the thickness of the photosensitive layer is 5 to 1
It is preferably about 00 μm, more preferably about 10 to 50 μm. In the case of a laminated photoreceptor, the thickness of the charge generation layer is 0.01 to 5 μm,
Further, the thickness is preferably 0.1 to 3 μm, and the thickness of the charge transport layer is preferably 2 to 100 μm, more preferably about 5 to 50 μm.

In the photosensitive layer, in addition to the above-described components, various conventionally known additives such as an antioxidant, a radical scavenger, a singlet quencher, Deterioration inhibitors such as UV absorbers, softeners,
Plasticizers, surface modifiers, extenders, thickeners, dispersion stabilizers, waxes, acceptors, donors, and the like can be added. Also, in order to improve the sensitivity of the photosensitive layer, for example,
Known sensitizers such as terphenyl, halonaphthoquinones, and acenaphthylene may be used in combination with the charge generator.

A barrier layer may be formed between the support and the photosensitive layer or between the laminated layers as long as the characteristics of the photosensitive member are not impaired.

As the support on which the photosensitive layer is formed, various conductive materials can be used.
Iron, aluminum, copper, tin, platinum, silver, vanadium,
Molybdenum, chromium, cadmium, titanium, nickel,
Examples of the material include simple metals such as palladium, indium, stainless steel, and brass; plastic materials on which the above metals are deposited or laminated; glass coated with aluminum iodide, tin oxide, indium oxide, and the like.

The support may be in the form of a sheet, a drum, or the like, depending on the structure of the image forming apparatus to be used. The support itself has conductivity, or the surface of the support has What is necessary is just to have electroconductivity. The support preferably has a sufficient mechanical strength when used.

When the photosensitive layer is formed by a coating method, a charge generating agent, a charge transporting agent, a binder resin and the like described above together with a suitable solvent are mixed with a known method, for example, a roll mill, a ball mill, an attritor, a paint coater, and the like. What is necessary is just to disperse and mix using an acre, an ultrasonic disperser or the like to prepare a dispersion, apply it by a known means, and dry it.

Various organic solvents can be used as a solvent for preparing the above-mentioned dispersion liquid, for example, alcohols such as methanol, ethanol, isopropanol and butanol, and aliphatic solvents such as n-hexane, octane and cyclohexane. Hydrocarbons, aromatic hydrocarbons such as benzene, toluene, and xylene; halogenated hydrocarbons such as dichloromethane, dichloroethane, chloroform, carbon tetrachloride, and chlorobenzene; dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether. Ethers, ketones such as acetone, methyl ethyl ketone and cyclohexanone, esters such as ethyl acetate and methyl acetate, dimethylformaldehyde, dimethylformamide, dimethyls Rufoxide and the like. These solvents are used alone or in combination of two or more.

Further, in order to improve the dispersibility of the charge generating agent, the charge transporting agent and the like and the smoothness of the surface of the photosensitive layer, a surfactant, a leveling agent and the like may be used.

[0051]

The present invention will be described below with reference to examples and comparative examples. Note that the following embodiments are merely examples embodying the present invention, and do not limit the technical scope of the present invention.

Examples 1 to 19 5.5 parts by weight of an X-type metal-free phthalocyanine (PcH ₂ ) as a charge generating agent and one (35 to 75 parts by weight) selected from HTM-1 to -5 as a hole transporting agent Part), ETM-1 to 1 as electron transporting agents
-3, 100 parts by weight of a polyester resin having a weight average molecular weight of 50,000 (Resin-1 to -3) as a binder resin together with 400 parts by weight of tetrahydrofuran in a ball mill for 24 hours. Alternatively, it was dissolved to prepare a coating solution for a single-layer photosensitive layer (solid content of the charge transporting agent relative to the total solid content: 4).
6.0-55.2 wt%).

[Comparative Examples 1 to 5] As binder resins,
Except that a bisphenol Z-type polycarbonate resin (Resin-4) having a weight average molecular weight of 50,000 was used, a coating solution for a single-layer photoreceptor was prepared in the same manner as in Examples 1 to 5.

[HTM-1]

Embedded image

[HTM-2]

Embedded image

[HTM-3]

Embedded image

[HTM-4]

Embedded image

[HTM-5]

Embedded image

[ETM-1]

Embedded image

[ETM-2]

Embedded image

[ETM-3]

Embedded image

[Resin-1]

Embedded image

[Resin-2]

Embedded image

[Resin-3]

Embedded image

[Resin-4]

Embedded image

With respect to the photoreceptors of the above Examples and Comparative Examples,
The isoper resistance was evaluated by the following test.

<Isopar resistance test> Using the coating solutions obtained in Examples and Comparative Examples, a film having a thickness of 2
A single-layer type photosensitive layer having a thickness of 5 μm was prepared (heat treatment conditions: 125 ° C.,
35 minutes) A test piece of 5 cm × 5 cm was obtained. Next, the test piece was immersed in 100 g of Isopar H in a closed system at 50 ° C. for one week in a dark place. On the other hand, the hole transporting agent and the electron transporting agent were forcibly dissolved in Isopar H at a predetermined concentration, and a concentration-absorbance calibration curve at the peak wavelength of the hole transporting agent and the electron transporting agent was prepared by UV measurement. Then, UV measurement of Isopar H in which the test piece was immersed was performed, and the elution amount was calculated from the absorbance at the peak wavelength of the hole transporting agent and the electron transporting agent using the calibration curve. The smaller the elution amount, the higher the isopar resistance of the photoconductor.

The elution amount of the hole transport agent was 0.5 × 1
0 ^-3 mol / l or less was acceptable, and the elution amount of the electron transporting agent was 3 × 10 ^-3 mol / l or less. In particular, the elution amount of the hole transport agent is 0.25 × 10 ⁻³ mol / l or less, and the elution amount of the electron transport agent is 2 × 10 ⁻³ mol / l.
The following is preferred.

The appearance change of the photoreceptor surface was determined by immersing the test piece in Isopar H in a dark place at 50 ° C. for 3 weeks, taking out the test piece, air-drying Isopar H, and visually observing the photoreceptor surface. .

The case where there was no change on the surface of the photosensitive layer was evaluated as ○, the case where slight cracks occurred, and the case where cracks occurred on the entire surface of the test piece were evaluated as x. Since the change in appearance is evaluated by a severe immersion test, there is no problem in actual use even if the evaluation is Δ.

Table 1 shows the results of the above evaluation tests.

[0072]

[Table 1]

As shown in Table 1, a photosensitive layer comprising a binder resin containing at least a charge generating agent and a charge transport agent is provided on a conductive substrate, and the binder resin is a diol component represented by the general formulas [1] and [2]. Or a substantially linear polyester resin containing at least one dihydroxy compound represented by the formula [3] and at least a naphthalenedicarboxylic acid represented by the general formula [4] as an acid component: The electrophotographic photoreceptor containing the compound had a small amount of the charge transport agent eluted and almost no change in appearance even when immersed in Isopar, as compared with the comparative example.

In particular, in the combination of the hole transporting agent represented by the general formula [5] and the electron transporting agent represented by the general formula [6] (Examples 1 to 3 and 6 to 8), the charge transport into the isopar The elution amount of the agent is the minimum (the hole transport agent elution amount is 0.2
5 × 10 ⁻³ mol / l or less, elution amount of electron transport agent 2 × 10
^-3 mol / l or less), and the isopar resistance was the best.

FIG. 1 shows the relationship between the amount of the charge transport agent eluted into the isopar and the solid content concentration of the total charge transport agent relative to the total solid content concentration (Examples 1, 16 to 19).
When the solid content concentration of all the charge transport agents exceeded 50 wt%, the amount of the charge transport agent eluted into the isopar increased.

From the above results, the type of the binder resin,
It has been clarified that the type of the charge transporting agent (hole transporting agent and electron transporting agent) and the content of the charge transporting agent have a great influence on the isoper resistance of the photoreceptor. It was a kind of the binder resin described in Item 1.

[0077]

According to the present invention, a photosensitive layer comprising a binder resin containing at least a charge generator and a charge transport agent is provided on a conductive substrate, and the binder resin is a diol component represented by the general formula [1], [2] or Contains a polyester resin that is a substantially linear polymer and contains at least one of the dihydroxy compounds represented by [3] and at least the naphthalenedicarboxylic acid represented by the general formula [4] as an acid component. The electrophotographic photoreceptor thus obtained can be used in a wet development type image forming apparatus using a developing solution of an isoper-based solvent, with a very small amount of charge transport agent eluted and without any change in appearance.

[0078]

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the amount of charge transport agent eluted into Isopar and the solid content concentration of all charge transport agents with respect to the total solid content concentration.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kyoichi Nakamura, 1-2-28 Tamazo, Chuo-ku, Osaka City Inside Kyocera Mita Co., Ltd. (72) Maki Uchida 1-2-28 Tamazo, Chuo-ku, Osaka Kyocera Mita Inside (72) Inventor Akira Urano 1-2-28 Tamazo, Chuo-ku, Osaka-shi F-term in Kyocera Mita Corporation (reference) 2H068 AA13 AA19 AA20 AA21 AA31 AA34 AA35 BA13 BA14 BA38 BA63 BB23 BB27 FC08 2H069 BA01

Claims (6)

[Claims] 1. A photosensitive layer comprising a binder resin containing at least a charge generator and a charge transport agent on a conductive substrate, wherein the binder resin is a diol component represented by the general formula [1], [2] or Contains a polyester resin that is a substantially linear polymer and contains at least one of the dihydroxy compounds represented by [3] and at least the naphthalenedicarboxylic acid represented by the general formula [4] as an acid component. And an electrophotographic photoreceptor for use in a wet development type image forming apparatus using a developing solution in which toner particles are dispersed in an isoper-based solvent. General formula [1]: General formula [2]: General formula [3]: (In the general formulas [1], [2] and [3], R ¹
Is an alkylene group having 2 to 4 carbon atoms, R ² , R ³ , R ⁴ and R ⁵
Is the same or different and represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aryl group or an aralkyl group. In the general formula [2], n is an integer of 2 or more. In the general formula [3], R ⁶ and R ⁷ are the same or different and each have 1 carbon atom.
And 10 to 10 alkyl groups. ) General formula [4]: 2. The method according to claim 1, wherein the charge transporting agent contains a hole transporting agent represented by the general formula [5], and the solids concentration of the charge transporting agent is 50 wt% or less of the total solids concentration. Item 8. The electrophotographic photosensitive member according to Item 1. General formula [5]: (In the general formula [5], R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are the same or different, and are an alkyl group, an alkoxy group, an aryl group,
Represents an aralkyl group or a halogen atom, m, n, p
And q are the same or different and each represents an integer of 0 to 3. R ¹²
And R ¹³ are the same or different and each represent a hydrogen atom or an alkyl group. Further, -X- is Or Is shown. ) 3. The electrophotographic photosensitive member according to claim 1, wherein said charge generating agent contains a phthalocyanine pigment. 4. The method according to claim 1, wherein the photosensitive layer comprises at least a charge generator.
2. The electrophotographic photoreceptor according to claim 1, wherein the electrophotographic photoreceptor is a single layer type containing both a hole transporting agent and an electron transporting agent as a charge transporting agent. 5. The single-layer electrophotographic photosensitive member according to claim 4, wherein the total weight of the hole transporting agent in the charge transporting agent is equal to or less than the total weight of the electron transporting agent. 6. The single-layer type electrophotographic photoreceptor according to claim 4, wherein said electron transporting agent contains a compound represented by the general formula [6]. General formula [6]: (In the general formula [6], R ¹⁴ represents a halogen atom, an optionally substituted alkyl group or an aryl group, R ¹⁵ represents an optionally substituted alkyl group or an aryl group,
Or a group: -OR ^15a . R ^15a represents an alkyl group or an aryl group which may have a substituent. )