JPH07301926A - Electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE:To obtain single layer type and laminate type electrophotographic photoreceptors having high sensitivity, low residual potential and superior quality. CONSTITUTION:This electrophotographic photoreceptor has a photosensitive layer on the electric conductive substrate and the photosensitive layer contains an electric charge generating material and a compd. represented by the formula as an electric charge transferring material. In the formula, each of R<1>-R<4> is H, halogen, 1-4C alkyl, 7-12C aralkyl, 1-4C alkoxy or 6-18C aryl.

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 in an image forming apparatus such as an electrostatic copying machine or a laser printer. More specifically, it relates to an electrophotographic photoreceptor having high sensitivity and low residual potential.

[0002]

2. Description of the Related Art As an electrophotographic photosensitive member used in an electrophotographic method, an organic photosensitive member which is mainly put into practical use at present has a function of generating electric charges by exposure and a function of transporting the generated electric charges. Is a functionally separated type in which is separated into different substances. In this type of photoconductor, a substance having a high charge generation efficiency and a substance having a high transport efficiency can be appropriately combined, and there is an advantage that the range of selection of the material is widened.

The function-separated type organic photoreceptor includes a single layer type and a laminated type. The single-layer type organic photoreceptor has a structure in which all materials such as a charge generation material and a charge transport material are dispersed in a binder resin in the same layer. The laminated type has a laminated structure including a charge generation layer (CGL) in which a charge generation material is dispersed in a binder resin and a charge transport layer (CTL) in which a charge transport material is dispersed in a binder resin. The laminated type organic photoconductor includes a positive charging type and a negative charging type, but a negative charging type is generally used.

The single-layer type organic photoreceptor is composed of a solvent, a binder resin,
The charge generating material and the charge transporting material are mixed to prepare a coating liquid, and the coating liquid is coated on a conductive substrate and dried. Alternatively, the charge generating material and the charge transporting material are mixed to prepare an immersion liquid, the conductive substrate is immersed in the immersion liquid, and then dried. In the laminated organic photoreceptor, a charge generating material or a charge transporting material is separately mixed with a solvent and a binder resin, and the mixture is sequentially coated on a conductive substrate, or sequentially dipped and dried to form a photosensitive layer. Created by forming.

The electrophotographic photosensitive member produced by the above coating or dipping has high film-forming performance, and since it can be produced by a simple means such as coating or dipping, it has high productivity and a material to be used is selected. Since it has the advantage that the photosensitivity can be controlled freely, it has been extensively studied in the past.

[0006]

One of the reasons why the sensitivity of the electrophotographic photosensitive member is not sufficient is that the residual potential is high.
Various charge transport materials have been studied for the purpose of lowering the residual potential of the electrophotographic photosensitive member and improving the sensitivity. For example, polyvinylcarbazole, oxadiazole compounds, pyrazoline compounds, amine compounds, hydrazone compounds, etc. have been proposed. However, the above-mentioned charge transport material has a relatively low drift mobility indicating the charge transport ability and a large electric field strength dependency of the drift mobility, and therefore has a drawback that the charge mobility in a low electric field is small and the residual potential is high. There is. In order to eliminate these drawbacks, JP-A-4-
13776 discloses an m-phenylenediamine compound as a charge transport material. This compound has light resistance and excellent light stability, and the sensitivity of the electrophotographic photoreceptor using this compound is also good, but it cannot be said to be sufficient. Therefore, a charge transport material for increasing the sensitivity of the electrophotographic photoreceptor is desired, and an electrophotographic photoreceptor containing this electron transport material is desired.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a charge transport material having a high sensitivity and a low residual potential, which has an excellent effect. An object is to provide an excellent electrophotographic photoreceptor.

[0008]

The electrophotographic photosensitive member of the present invention is an electrophotographic photosensitive member having a photosensitive layer on a conductive substrate, and the photosensitive layer has the following structure as a charge generating material and a charge transporting material. A compound represented by the general formula (1);

[0009]

[Chemical 2]

(Here, R ¹ , R ² , R ³ , and R ⁴ are each independently a hydrogen atom, a halogen atom, or a carbon number of 1 to 1.
And an alkyl group having 4 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an aryl group having 6 to 18 carbon atoms).
Thereby, the above object is achieved.

In a preferred embodiment, the charge generating material is
It is a perylene pigment, a phthalocyanine pigment, or a bisazo pigment. Thereby, the above object is achieved.

The organophotoreceptor of the present invention may be either a single layer type or a laminated type. Thereby, the above object is achieved.

[0013]

By charging and exposing the electrophotographic photosensitive member of the present invention, holes generated in the charge generating material are efficiently transported to the surface of the photosensitive member by the charge transporting material without causing space charge to the surface charge. Disappears. Since the structure of the charge transporting material used for the photoreceptor of the present invention is spread in a plane, overlapping of π electrons between molecules is likely to occur, and holes are easily transported by hopping. It is thought that the movement of charges in the molecule will also be smooth.
Therefore, as will be shown in Examples described later, the photoreceptor of the present invention using this compound as a charge transport agent can be used in both single-layer type and multi-layer type electrophotographic photoreceptors to obtain a residual potential and a half value. The effect that the sensitivity indicated by the exposure dose is improved can be obtained.

[0014]

Preferred Embodiments Materials used for the electrophotographic photosensitive member of the present invention and preparation of the photosensitive member will be described below.

(Charge Transport Material) As the charge transport material,
The compound represented by the general formula (1) is used.

[0016]

[Chemical 3]

Here, R ¹ , R ² , R ³ , and R ⁴ are each independently a hydrogen atom, a halogen atom, and a carbon number of 1 to 4.
Is an alkyl group having 7 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an aryl group having 6 to 18 carbon atoms.

Examples of preferred combinations of R ¹ , R ² , R ³ and R ⁴ are shown in Table 1 below. R ¹ , R ² shown in Table 1,
R ³ and R ⁴ may be present at any position on the benzene ring of the general formula (1) except for a hydrogen atom, and a plurality of R ³ and R ⁴ may be present on the same ring.

[0019]

[Table 1]

Specific examples of preferred compounds as the charge transport material include the compounds (1) shown in Tables 2, 3 and 4 below.
(9) are mentioned.

[0021]

[Table 2]

[0022]

[Table 3]

[0023]

[Table 4]

The above charge transport material can be synthesized, for example, by the following method.

[0025]

[Chemical 4]

In the formula, R ⁿ and R ^m are each independently
Hydrogen atom, halogen atom, alkyl group having 1 to 4 carbon atoms,
An aralkyl group having 7 to 12 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an aryl group having 6 to 18 carbon atoms.

A biphenyl derivative represented by the formula (1),
The aniline derivative represented by the formula (2) is reacted under reflux in a nitrogen stream in the presence of iodine to obtain a tetraamine compound represented by the formula (3). Then, by reacting the compound of formula (3) with the iodobenzene derivative represented by (4) in the presence of calcium carbonate and copper powder in a solvent (for example, nitrobenzene), the compound represented by the general formula (1) is obtained. Charge transport materials can be synthesized.

A compound other than the compound obtained by the above reaction,
For example, when synthesizing a compound in which R ¹ , R ² , R ³ , and R ⁴ are all different substituents, the molar ratio of the starting materials is appropriately adjusted, and R ¹ , R ² , R ³ are gradually adjusted. , And a phenyl group having R ⁴ can be introduced.
When it has halogen as a substituent, it can be synthesized by first synthesizing the compound and then halogenating it. Chlorine is preferred as the halogen.

(Charge Generating Material) As the charge generating material,
For example, selenium, selenium-tellurium, amorphous silicon, pyrylium salt, perylene pigment, ansanthuron pigment, indigo pigment, triphenylmethane pigment, slene pigment, toluidine pigment, pyrazoline pigment, phthalocyanine pigment, azo. Examples thereof include pigments and quinacridone pigments. The above charge generating materials may be used alone or in combination of two or more.

Suitable charge generating materials include perylene pigments, phthalocyanine pigments and azo pigments, especially bisazo pigments.

As the perylene pigment, a compound represented by the following general formula (A) can be used.

[0032]

[Chemical 5]

In the formula, R ⁷ and R ⁸ are each independently a hydrogen atom, a halogen atom, 1 or an alkyl group having 1 to 6 carbon atoms which may have a substituent of 2 or more, and 7 to 1 carbon atoms.
It may be an aralkyl group having 2 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 18 carbon atoms.

A particularly preferred perylene pigment is a compound in which R ⁷ and R ⁸ are each independently an aryl group, and examples thereof include compounds represented by the following formula (a).

[0035]

[Chemical 6]

As the phthalocyanine pigment, a compound represented by the following general formula (B) can be used.

[0037]

[Chemical 7]

In the formula, M represents a metal atom or two hydrogen atoms.

The phthalocyanine may be either metal phthalocyanine or metal free phthalocyanine, but metal free phthalocyanine is preferable from the viewpoint of charge generation efficiency and the like. Examples of the metal-free phthalocyanine include x-type, β-type, α-type, or γ-type metal-free phthalocyanine.

A particularly preferred phthalocyanine pigment is a metal-free compound represented by the following formula (b).

[0041]

[Chemical 8]

Examples of the bisazo pigment include compounds represented by the following general formula (C).

[0043]

[Chemical 9]

In the formula, R ⁹ is a hydrogen atom, or 1,
Or an alkyl group, an aryl group or a heterocyclic group which may have two or more substituents, n is 0 or 1, and
A ₁ and A ₂ each independently represent a coupler residue.

In the bisazo pigment represented by the general formula (C), the alkyl group corresponding to R ⁹ is, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group or t-butyl group. Groups, pentyl groups, hexyl groups and the like can be used.

As the aryl group corresponding to R ⁹ , for example, a phenyl group, an o-terphenyl group, a naphthyl group, an anthryl group, a phenanthryl group and the like can be used.

Examples of the heterocyclic group corresponding to R ⁹ include thienyl group, pyrrolyl group, pyrrolidinyl group, oxazolyl group, isoxazolyl group, thiazolyl group, isothiazolyl group, imidazolyl group, 2H-imidazolyl group,
Pyrazolyl group, triazolyl group, tetrazolyl group, pyranyl group, pyridyl group, piperidyl group, piperidino group, 3
A morpholinyl group, a morpholino group, a thiazolyl group, and a heterocyclic group in which these groups are condensed with an aromatic ring can be used.

Examples of the substituent that the alkyl group, aryl group, and heterocyclic group corresponding to R ⁹ may have include a halogen atom, an amino group, a hydroxyl group, an optionally esterified carboxyl group, and a cyano group. Group, carbon number 1-6
, An alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms which may have an aryl group, and the like can be used.

In the bisazo pigment represented by the general formula (C), examples of the coupler residue represented by A ₁ and A ₂ include groups represented by the following formulas (i) to (vii).

[0050]

[Chemical 10]

R ¹⁰ in the above formula (i) may be a carbamoyl group, a sulfamoyl group, an allofanoyl group, an oxamoyl group, an anthraniloyl group, a carbazoyl group, a glycyl group, a hydantoyl group, a phthalamoyl group, or a succinamoyl group. These groups may further have, as a substituent, a halogen atom, an optionally substituted phenyl group, an optionally substituted naphthyl group, an alkyl group, an alkenyl group, a carbonyl group, a carboxyl group and the like.

R ¹¹ in the above formulas (i) and (ii) is an atomic group necessary for forming an aromatic ring, a polycyclic hydrocarbon or a heterocycle by being condensed with a benzene ring having a hydroxyl group. , These rings may have the same substituents as used for R ¹⁰ above.

R ¹² in the above formula (ii) represents an oxygen atom, a sulfur atom or an imino group.

R ¹³ in the above formula (ii) represents a divalent chain hydrocarbon or aromatic hydrocarbon, and these groups may have the same substituents as used for R ¹⁰ .

R ¹⁴ in the above formulas (iii) and (iv) is
It represents an alkyl group, an aralkyl group, an aryl group, or a heterocyclic group, and these groups may have the same substituents as used for R ¹⁰ above.

R ¹⁵ in the above formulas (v) and (vi) is 2
Represents a valent chain hydrocarbon, or an aromatic hydrocarbon, and these groups may have the same substituents as used for R ¹⁰ above.

R ¹⁶ in the above formula (vii) represents a hydrogen atom, an alkyl group, an amino group, a carbamoyl group, a sulfamoyl group, an allofanoyl group, a carboxyl group, an ester of a carboxyl group, an aryl group or a cyano group, and hydrogen The non-atom groups may have the same substituents as used for R ¹⁰ above.

R ¹⁷ in the above formula (vii) represents an alkyl group or an aryl group, and these groups may have the same substituents as used for R ¹⁰ .

In R ¹¹ , the atomic group necessary for condensation with a benzene ring having a hydroxyl group to form an aromatic ring is, for example, an alkylene group such as a methylene group, an ethylene group, a propylene group or a butylene group. Can be used.
Examples of the aromatic ring formed by R ¹¹ include naphthalene ring, anthracene ring, phenanthrene ring, pyrene ring, chrysene ring, and naphthacene ring.

In R ¹¹ , the atomic group necessary for condensation with a benzene ring having a hydroxyl group to form a polycyclic hydrocarbon is, for example, a methylene group, an ethylene group, a propylene group or a butylene group. Alkylene groups can be used. Examples of the polycyclic hydrocarbon formed by R ¹¹ include
For example, there are a carbazole ring, a benzocarbazole ring, a dibenzofuran ring and the like.

Examples of the atomic group necessary for forming a heterocyclic group by condensation with the benzene ring having a hydroxyl group in R ¹¹ include, for example, benzofuranyl group, benzothiophenyl group, indolyl group, 1H-indolyl group. , Benzoxazolyl group, benzothiazolyl group, 1H-indazolyl group, benzimidazolyl group, chromenyl group, chromanyl group, isochromanyl group, quinolinyl group, isoquinolinyl group, cinnolinyl group, phthalazinyl group, quinazoniryl group, quinoxalinyl group, dibenzofuranyl group, A carbazolyl group, a xanthenyl group, an acridinyl group, a phenanthridinyl group, a phenazinyl group, a phenoxazinyl group, a thianthrenyl group and the like can be used.

The aromatic heterocyclic group formed by R ¹¹ includes, for example, thienyl group, furyl group, pyrrolyl group,
Oxazolyl group, isoxazolyl group, thiazolyl group,
Isothiazolyl group, imidazolyl group, pyrazolyl group, triazolyl group, tetrazolyl group, pyridyl group, thiazolyl group, and further heterocyclic group condensed with another aromatic ring, for example, benzofuranyl group, benzimidazolyl group,
Examples include a benzoxazolyl group, a benzothiazolyl group, and a quinolyl group.

In R ¹³ and R ¹⁵ , examples of the divalent chain hydrocarbon include ethylene group, propylene group and butylene group, and examples of the divalent aromatic hydrocarbon include phenylene group and naphthylene group. Groups, phenanthrylene groups and the like can be used.

In R ¹⁴ above, the heterocyclic group is
For example, a pyridyl group, a pyrazyl group, a thienyl group, an indolyl group and the like can be used.

Examples of the aromatic heterocyclic group formed by R ¹⁵ include a benzimidazole group, a benzo [f] benzimidazole group, a dibenzo [e, g] benzimidazole group, and a benzopyrimidine group.

In R ¹⁶ , the ester of the carboxyl group may be, for example, methyl ester, ethyl ester, propyl ester, butyl ester or the like.

A particularly preferred bisazo pigment is a compound having a group represented by formula (i) as a coupler residue, and examples thereof include compounds represented by the following formula (c).

[0068]

[Chemical 11]

The above charge generating materials may be used alone or in combination of two or more.

(Binder Resin) As the binder resin, various conventionally known resins can be used. For example, styrene-based polymer, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer,
Acrylic polymer, styrene-acrylic copolymer, ethylene-vinyl acetate copolymer, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyester, alkyd resin, polyamide, polyurethane, acrylic modified urethane resin, epoxy resin , Polycarbonate, polyarylate, polysulfone, diallylphthalate resin, silicone resin, ketone resin, polyvinyl butyral resin, polyether resin, phenol resin, and various polymers. Photocurable resins such as epoxy acrylates may also be used. In addition, photoconductive polymers such as poly
-N-vinylcarbazole can also be used as the binder resin.

(Conductive Substrate) As the conductive substrate on which the organic photoreceptor is formed, various conductive materials can be used. For example, aluminum, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium,
A simple metal such as nickel, palladium, indium, stainless steel, or brass, a plastic material in which the above metal is vapor-deposited or laminated, or glass coated with aluminum iodide, tin oxide, indium oxide, or the like can be used.

As the conductive substrate, any one having a sheet shape, a drum shape or the like may be used as long as the substrate itself has conductivity or the surface of the substrate has conductivity.
It is preferable that the conductive substrate has sufficient mechanical strength when used.

(Other Additives) In addition to the above, known sensitizers such as terphenyl, halonaphthoquinones, and acenaphthylene may be added to the electrophotographic photoreceptor of the present invention in combination with the charge generating material. Further, known additives such as deterioration inhibitors such as fluorene compounds, antioxidants and ultraviolet absorbers, or plasticizers may be added.

(Construction of Photoreceptor) The electrophotographic photoreceptor of the present invention is a single-layer type photoreceptor formed on a conductive substrate or a laminated type photoreceptor having a charge generation layer and a charge transport layer. As another layer, it may have a protective layer. For example, it may have a protective layer formed on the surface of the charge transport layer.

The charge transport material has a sufficient charge transport capacity.
In addition, it can be used in various proportions within a range that does not crystallize in the binder resin. It may preferably contain 30 to 200 parts by weight, more preferably 50 to 130 parts by weight, based on 100 parts by weight of the binder resin. If the amount is less than 30 parts by weight, the charge transporting rate will be slow, and if it exceeds 200 parts by weight, the solubility in the resin will be poor and crystallization of the charge transporting material will occur.

Charge generating material (for example, the above-mentioned perylene pigment, phthalocyanine pigment, or bisazo pigment)
Can be used in various proportions with respect to the binder resin. Preferably, it is 1 to 1000 parts by weight, more preferably 2 to 15 parts by weight in the single layer type, and 100 to 500 parts by weight in the laminated type, relative to 100 parts by weight of the binder resin.

In the case of the single layer type, the thickness of the photosensitive layer is 2 to 100.
It is preferably formed to a thickness of about μm, more preferably 5 to 50 μm.

In the case of the laminated type, the charge generation layer is 0.01 to 5
The thickness of the charge transport layer is preferably about 2 to 100 μm, particularly 5 to 5 μm.
The thickness is preferably about 0 μm.

(Preparation of Photoreceptor) In the electrophotographic photoreceptor of the present invention, a single layer having the above charge generating material and charge transporting material is formed on a conductive substrate by means of coating or the like, or Formed by forming a charge generating layer containing a charge generating material and forming a charge transporting layer containing a charge transporting material on the charge generating layer, or by forming a charge generating layer on the charge transporting layer. obtain. The charge generation layer can also be formed by vapor deposition.

The coating liquid for forming the single-layer type or laminated type electrophotographic photosensitive member contains the above-mentioned charge generating material and / or
Alternatively, a charge-transporting material, a binder resin, other necessary additives, and the like, together with a suitable solvent, are conventionally known methods, for example,
By mixing using a roll mill, ball mill, attritor, paint shaker, ultrasonic disperser, etc.,
Can be prepared.

The solvent capable of dissolving the charge generating material, the charge transporting material, the binder resin and the like can be appropriately selected from conventionally known solvents according to the kind of the binder resin and the like. For example, alcohols such as methanol, ethanol, propanol, isopropanol and butanol, aliphatic hydrocarbons such as n-hexane, octane and cyclohexane, aromatic hydrocarbons such as benzene, toluene and xylene, dichloromethane, dichloroethane and tetrachloride. carbon,
Halogenated hydrocarbons such as chlorobenzene, ethers such as dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ketones such as acetone, methyl ethyl ketone, cyclohexanone, esters such as ethyl acetate, methyl acetate, etc. Various solvents may be mentioned. These solvents may be used alone or in combination of two or more.

Further, in order to improve the dispersibility of the charge generating material and / or the charge transporting material, or the coating property, a surfactant or a leveling agent may be added.

In the case of producing a laminated type organic photoreceptor, a coating liquid for a layer to be formed later, for example, a charge transport layer, contains a solvent which does not dissolve the previously formed layer, for example, the charge generation layer. It is preferable to use.

The coating solution prepared by the above method was applied onto the conductive substrate so as to have the above-mentioned preferable layer thickness.
The photoconductor can be formed by coating and drying.

[0085]

EXAMPLES The present invention will now be described in more detail based on examples.

(Preparation of Charge Transfer Agent) The following compounds (1 ′), (2 ′) and (4 ′) were used as starting materials.
The compound (1) shown in Table 2 was synthesized by the above method.

[0087]

[Chemical 12]

12.96 g of the compound represented by (1 ′) and 13.91 g of p-methylaniline represented by (2 ′) were reacted in the presence of iodine in a nitrogen stream at 250 to 300 ° C. for 24 hours,
11.7 g of (3 ') was obtained (yield 34.0%), and this and 11.48 g of p-methyl iodobenzene were added in the presence of calcium carbonate 5.35 g and copper powder 1 g in nitrobenzene 150 ml at 250 to 300 ° C.
After refluxing for 24 hours, 4.67 g of compound (1) was synthesized.
The yield was 25.0%. The results of elemental analysis are as follows.

Theoretical value (%) as C ₆₈ H ₆₂ N ₄ C = 87.31, H = 6.69, N = 5.99 Actual value (%) C = 86.91, H = 6.92, N = 6.17 (Single layer type electrophotographic photosensitive member As a charge generation material,
The compounds represented by the following formulas (a), (b) and (c) were used.

[0090]

[Chemical 13]

As the charge transport material, the above compound (1) and the compound prepared in the same manner as in the above compound (1) were used.
Of the compounds shown in 3 and 4, (2) to (6) and (8) were used. When using the compound of the above formula (c) as the charge generating material, the compound (7) was further used.

8 parts by weight of the charge generating material, 100 parts by weight of the charge transporting material, 100 parts by weight of a polycarbonate resin (Polycarbonate Z200 manufactured by Mitsubishi Gas Chemical Co., Inc.) as a binder resin, and a predetermined amount of tetrahydrofuran. Combine with (THF) and use ultrasonic disperser 2
The mixture was dispersed for 1 minute to prepare a coating solution for a single-layer type photosensitive layer.

This coating solution was applied onto an aluminum tube having an outer diameter of 78 mm and a length of 340 mm by a dip coating method, and then 100
It was heated and dried at 30 ° C. for 30 minutes to prepare a single-layer type electrophotographic photosensitive member having a thickness of 24 μm.

As a comparative example, a single-layer type photoreceptor was prepared in the same manner as described above, except that an m-phenylenediamine compound represented by the following formula (d) was used as the charge transport agent.

[0095]

[Chemical 14]

(Preparation of Laminated Electrophotographic Photoreceptor) 100 parts by weight of the compounds represented by the above formulas (a), (b) and (c) are used as a charge generating material, and polyvinyl butyral (Sekisui Chemical Co., Ltd.) is used as a binder resin. Co., Ltd., S-REC BL1)
100 parts by weight of THF and a predetermined amount of THF were charged in a ball mill and stirred for 24 hours to prepare a charge generation layer coating liquid.

This charge generation layer coating solution was applied onto an aluminum base tube having an outer diameter of 78 mm and a length of 340 mm by a dip coating method, followed by heating and drying at 100 ° C. for 30 minutes to give a thickness of 0.5 μm.
Was prepared.

Next, as a charge transport material, the above-mentioned Table 2,
Of the compounds shown in 3 and 4, 100 parts by weight of each of (1) to (6) and (8), 100 parts by weight of a polycarbonate resin (polycarbonate Z200 manufactured by Mitsubishi Gas Chemical Co., Inc.) as a binder resin, and A fixed amount of toluene was combined and stirred and mixed using a homomixer to prepare a charge transport layer coating liquid. When the compound of the above formula (c) was used as the charge generating material, it was further prepared using the compound (7).

This coating solution was applied on the surface of the charge generation layer prepared above by the dip coating method and then dried by heating at 100 ° C. for 30 minutes to prepare a laminated electrophotographic photoreceptor having a thickness of 20 μm.

As a comparative example, a laminated electrophotographic photosensitive member was prepared in the same manner except that the compound (d) was used as the charge transport material.

(Evaluation of Electrophotographic Photosensitive Member) The single-layer type electrophotographic photosensitive members (Examples 1 to 22 and Comparative Examples 1 to 3 shown in Table 5) produced as described above, and laminated type electrophotographic The initial surface potential V ₀ , the half-exposure amount E1 / 2, and the residual potential VR of the electrophotographic photoconductors of the photoconductors (Examples 31 to 52 and Comparative Examples 4 to 6 shown in Table 6) were measured.

(Measurement of Initial Surface Potential V ₀ ) Single-layer and multi-layer type electrophotographic photoconductors were loaded in a drum sensitivity tester (CYNTHIA30M manufactured by Gentec Co.), and the surfaces thereof were positively charged to obtain the respective photoconductors. The initial surface potential V ₀ (V) of was measured.

(Measurement of Half-Exposure Amount E1 / 2 and Residual Potential VR) Single-layer type and multi-layer type electrophotographic photoreceptors using the charge generating materials represented by the formulas (a) and (c) (Examples 1 to 1) 7, 1
5-22, 31-37, 45-52 and Comparative Example 1,
For 3, 4, and 6), the measurement was performed by the following method.

Each of the electrophotographic photosensitive members in the charged state was exposed for 1 second using a halogen lamp (exposure intensity 0.92 mW / cm ² ) as an exposure light source, and the surface potential was 1 at the initial surface potential V ₀ .
Half-exposure dose E1 / 2 (μ
J / cm ² ) was calculated. The surface potential 0.15 seconds after the start of exposure was defined as the residual potential VR.

On the other hand, single-layer type and multi-layer type electrophotographic photoconductors using the charge generating material represented by the formula (b) (Examples 8 to 1)
4, 38 to 44, and Comparative Examples 2 and 5) were measured by the following method.

Monochromatic light (λ = 78) obtained by dispersing Xe lamp light as an exposure light source on each electrophotographic photosensitive member in the charged state
0 nm, exposure intensity 10 μW / cm ² ) and exposed for 1 second, and the time until the surface potential becomes half of the initial surface potential V ₀ is determined, and the half-exposure amount E 1/2 (μJ / cm ² ) Was calculated.
In addition, the surface potential 0.5 seconds after the start of exposure is determined by the residual potential V
R.

(Results) The results for the single-layer type electrophotographic photosensitive member are shown in Table 5, and the results for the multi-layer type electrophotographic photosensitive member are shown in Table 6, respectively.

[0108]

[Table 5]

[0109]

[Table 6]

As is clear from Tables 5 and 6, the photoconductor of the present invention has excellent sensitivity and a small residual potential as compared with the conventional photoconductors.

[0111]

EFFECTS OF THE INVENTION According to the present invention, in both single-layer type and multi-layer type electrophotographic photoconductors, by containing the compound represented by the general formula (1) as a charge transport material, high sensitivity can be obtained. It is possible to obtain an excellent electrophotographic photoreceptor.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Toshikazu Uegaki 1-2-2 Tamatsukuri, Chuo-ku, Osaka City Mita Engineering Co., Ltd. (72) Sakae Saito 1-2-2 Tamatsukuri, Chuo-ku, Osaka City No. Mita Kogyo Co., Ltd. (72) Inventor Maki Uchida 1-2-2 Tamatsukuri, Chuo-ku, Osaka Mita Kogyo Co., Ltd.

Claims (4)

[Claims] 1. An electrophotographic photoreceptor having a photosensitive layer on a conductive substrate, the photosensitive layer containing a charge generating material and a compound represented by the following general formula (1) as a charge transporting material. An electrophotographic photoreceptor. [Chemical 1] Here, R ¹ , R ² , R ³ , and R ⁴ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, and 1 to 4 carbon atoms. Or an aryl group having 6 to 18 carbon atoms. 2. The charge generation material is a perylene-based pigment,
A phthalocyanine pigment or a bisazo pigment,
The electrophotographic photosensitive member according to claim 1. 3. The electrophotographic photosensitive member according to claim 1, wherein the photosensitive member is a single layer type. 4. The electrophotographic photosensitive member according to claim 1, wherein the photosensitive member is a laminated type.