JPH06130702A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To provide an electrophotographic sensitive body high in sensitivity and superior in repetition characteristics by using the combination of an electric charge generating material composed of a specified bisazo pigment and a specified charge transfer material. CONSTITUTION:This electrophotographic sensitive body contains in a photosensitive layer formed on a conductive substrate as the charge generating material the bisazo pigment represented by formula I and as a charge transfer material represented by formula II or III, and in formulae I-III, A is a coupler residue; R1 is H, alkyl, aryl, or a heterocyclic group; each of R2 and R8 is H, alkyl, etc., ; each of R3 and r9 is H, alkoxy, etc., each of R4-R7 and R10-R13 is H, halogen, etc., and R14 is H, amino, etc. This charge transfer material can be used in combination with the conventional known charge transfer material, such as an electron-attractive compound like dibromomaleic anhydride and an electron donor like 2,5-di(4-methylaminophenyl), etc.

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 using an electrophotographic method such as an electrostatic copying machine and a laser beam printer.

[0002]

2. Description of the Related Art The electrophotographic method such as the Carlson process is a step of uniformly charging the surface of an electrophotographic photosensitive member by corona discharge, and exposing the charged surface of the electrophotographic photosensitive member to an electrostatic latent image on the surface. An exposure step of forming an image, a developing step of bringing a developer into contact with the formed electrostatic latent image, and developing the electrostatic latent image into a toner image by toner contained in the developer, and a toner image Transfer step of transferring the toner to paper, a fixing step of fixing the transferred toner image, and a transfer step,
And a cleaning step for removing the toner remaining on the photoconductor.

As the electrophotographic photosensitive member used in the above electrophotographic method, one using a specific bisazo pigment is known. (See JP-A 1-2202757).

[0004]

By the way, in order to prepare an organic photoreceptor using a charge generating material and a charge transporting material, electrophotographic characteristics such as sensitivity, potential holding property, potential stability and residual potential are satisfied. In order to do so, materials with good matching must be selected. For example, no matter how much charge-generating material generates sufficient charge, satisfactory electrophotographic characteristics cannot be obtained unless it is combined with a charge-transporting material capable of efficiently injecting and transporting the charge. .

Japanese Patent Laid-Open No. 1-220757 discloses that a photosensitive member stable to heat and light can be obtained by using the general formula (1) and various carrier-moving substances. There is. However, the charge generating material disclosed in the above publication has a phthalocyanine-based pigment, a perylene-based pigment, a fluorenone-type bisazo pigment (JP-A-57-96345), and a perinone skeleton, which are commonly used charge generating materials. Compared with an oxadiazole type azo pigment having a coupler (Japanese Patent Application Laid-Open No. 59-229564), etc., it is more susceptible to oxidative deterioration due to ozone, nitrogen oxides NOx, light, etc. generated in the copying machine, and the photoconductor characteristics. There is a drawback that it is easy to cause a decrease in It is presumed that the oxidative deterioration of the bisazo pigment (1) occurs because ozone or the like adsorbs to the azo group and decomposes the azo group.

Such oxidative deterioration is promoted when the bisazo pigment (1) is used in combination with a charge transport material which is an electron donating compound. This is because if the electron-donating compound has a strong basicity, the electron-donating substance coordinates with the azo group and increases the electron density of the azo group, which makes it more likely to be attacked by ozone and nitrogen oxides. To be

Moreover, even if the carrier transfer material exemplified in the above publication is used, a photoreceptor having high sensitivity and repeatability can be obtained without impairing the excellent characteristics of the bisazo pigment (1). I can't do that, and I'm still not satisfied enough. Therefore, the object of the present invention has been made in view of the above circumstances, and is required as an electrophotographic photosensitive member in the electrophotographic photosensitive member using the bisazo pigment represented by the general formula (1). It is to select a charge transport material that satisfies all the requirements with high performance.

[0008]

Therefore, the inventors of the present invention selected a specific charge transporting material for the bisazo pigment to obtain electrophotographic characteristics satisfying high performance, and used it. As a result of various studies on the charge transport material, the following general formula (1) as a charge generating material on the conductive substrate:

[0009]

[Chemical 4]

(In the formula, A is the same or different and represents a coupler residue, and R1 is a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group. The alkyl group, the aryl group, and the heterocyclic group are Which may have a substituent, n represents 0 or 1, and a bisazo pigment represented by the following general formula (2) or (3) as a charge transporting material:

[0011]

[Chemical 5]

(In the formula, R2 is a hydrogen atom, an alkyl group,
Represents an aryl group, R3 represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, an amino group, R4, R
5, R6, and R7 represent a hydrogen atom, an alkyl group, an alkoxy group, and a halogen atom, and p represents an integer of 0 to 2. )

[0013]

[Chemical 6]

(In the formula, R8 is a hydrogen atom, an alkyl group,
Represents an aryl group, R9 represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, an amino group, R10,
R11, R12, and R13 represent a hydrogen atom, an alkyl group, an alkoxy group, and a halogen atom, R14 represents a hydrogen atom, an alkyl group, a halogen atom, and an amino group, r is an integer of 0 to 2, and q is 1 Indicates an integer of 2. It was found that a photosensitive layer containing a compound represented by the formula (4) should be provided, and the present invention has been completed.

The effect of the selection of the specific charge transport material of the present invention has not been clarified, but it will be understood from the comparison between the examples and the comparative examples described later that the sensitivity is remarkably improved. In other words, it is assumed that problems such as fog do not occur even if the output of the exposure lamp that is standardly installed in the copying machine is not increased, which leads to a longer life of the exposure lamp and a reduction in power consumption. To be done.

[0016]

Preferred Embodiments Charge Generating Material In the bisazo pigment represented by the general formula (1), the alkyl group corresponding to the group R1 in the formula is, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group or a butyl group, Examples thereof include an isobutyl group, a t-butyl group, a pentyl group and a hexyl group. Examples of the aryl group include a phenyl group, an o-terphenyl group, a naphthyl group, an anthryl group,
Examples of the heterocyclic group include a phenanthryl group and the like.
For example, 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,
Examples thereof include pyranyl group, pyridyl group, piperidyl group, piperidino group, 3-morpholinyl group, morpholino group and thiazolyl group. It may also be a heterocyclic group condensed with an aromatic ring.

Examples of the substituent group substituting for the above group include a halogen atom, an amino group, a hydroxyl group, an optionally esterified carboxyl group, a cyano group, an alkyl group having 1 to 6 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms. Group, an alkenyl group having 2 to 6 carbon atoms, which may have an aryl group, and the like. Examples of the coupler residue represented by A include groups represented by general formulas (a) to (g).

[0018]

[Chemical 7]

In each formula, R ³⁰ represents 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, and a succinamoyl group. These groups, a halogen atom, a phenyl group which may have a substituent, a naphthyl group which may have a substituent, a nitro group, a cyano group, an alkyl group, an alkenyl group,
It may have a substituent such as a carbonyl group or a carboxyl group.

R ³¹ represents an atomic group necessary for forming an aromatic ring, a polycyclic hydrocarbon or a heterocyclic ring by condensing with R ³⁰ and the benzene ring having a hydroxyl group, and these rings are as described above. You may have the same substituent. R ³² represents an oxygen atom, a sulfur atom or an imino group. R ³³ represents a divalent chain hydrocarbon or aromatic hydrocarbon, and these groups may have the same substituents as described above.

R ³⁴ represents an alkyl group, an aralkyl group, an aryl group or a heterocyclic group, and these groups may have the same substituents as described above. R ³⁵ is a divalent chain hydrocarbon, an aromatic hydrocarbon, or the above general formula (e)
The following formula (h) in (f)

[0022]

[Chemical 8]

It represents an atomic group necessary for forming a heterocycle with the moiety represented by, and these rings may have the same substituents as described above. R ³⁶ is a hydrogen atom, an alkyl group,
It represents 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 groups other than a hydrogen atom may have the same substituents as described above.

R ³⁷ represents an alkyl group or an aryl group, and these groups may have the same substituents as described above.
Examples of the alkyl group include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t
A butyl group, a pentyl group, a hexyl group, etc., having 1 to 1 carbon atoms
And 6 lower alkyl groups.

As the aryl group, for example, a phenyl group,
Examples thereof include a tolyl group, a xylyl group, a biphenyl group, a naphthyl group, an anthryl group and a phenanthryl group. In R ³¹ , the atomic group necessary for forming an aromatic ring by condensing with R ³⁰ and a benzene ring having a hydroxyl group is, for example, an alkylene group such as a methylene group, an ethylene group, a propylene group or a butylene group. To be

The aromatic ring formed by the condensation of R ³¹ with R ³⁰ and a benzene ring having a hydroxyl group is
Examples thereof include naphthalene ring, anthracene ring, phenanthrene ring, pyrene ring, chrysene ring, and naphthacene ring. In R ³¹ , the atomic group necessary for condensing with R ³⁰ and a benzene ring having a hydroxyl group to form a polycyclic hydrocarbon is, for example, a methylene group, an ethylene group, a propylene group, a butylene group, or a carbon atom. Examples include alkylene groups of the numbers 1 to 4.

In R ³¹ , the polycyclic hydrocarbon condensed with R ³⁰ and a benzene ring having a hydroxyl group includes, for example, a carbazole ring, a benzocarbazole ring and a dibenzofuran ring. Further, in R ³¹ , the atomic group necessary for condensing with R ³⁰ and a benzene ring having a hydroxyl group to form a heterocycle is, for example, a benzofuranyl group, a benzothiophenyl group, an indolyl group, a 1H-indolyl group, a benzo Oxazolyl group, benzothiazolyl group, 1H-indadoryl group, benzimidazolyl group, chromenyl group, chromanyl group, isochromanyl group, quinolinyl group, isoquinolinyl group, cinnolinyl group, phthalazinyl group, quinazonilyl group, quinoxalinyl group, dibenzofuranyl group, carbazolyl group , Xanthenyl group, acridinyl group, phenanthridinyl group, phenazinyl group, phenoxazinyl group, thianthrenyl group and the like.

Examples of the aromatic heterocyclic group formed by condensation of the above R ³¹ and R ³⁰ and a benzene ring having a hydroxyl group include, for example, thienyl group, furyl group, pyrrolyl group, oxazolyl group, isoxazolyl group and thiazolyl group. , Isothiazolyl group, imidazolyl group, pyrazolyl group, triazolyl group, tetrazolyl group, pyridyl group and thiazolyl group. It may also be a heterocyclic group condensed with another aromatic ring (for example, a benzofuranyl group, a benzimidazolyl group, a benzoxazolyl group, a benzothiazolyl group, a quinolyl group).

In R ³³ and R ³⁵ , examples of the divalent chain hydrocarbon include ethylene group, propylene group and butylene group, and examples of the divalent aromatic hydrocarbon include phenylene group, naphthylene group, Examples thereof include a phenanthrylene group. Examples of the heterocyclic group for R ³⁴ include a pyridyl group, a pyrazyl group, a thienyl group, a pyranyl group and an indolyl group.

In R ³⁵ , the atomic group necessary for forming a heterocycle with the moiety represented by the formula (h) is, for example, phenylene group, naphthylene group, phenanthrylene group, ethylene group, propylene group, butylene. Groups and the like. Examples of the aromatic heterocyclic group formed by R ³⁵ and the moiety represented by the formula (h) include, for example, benzimidazole group, benzo [f] benzimidazole group, dibenzo [e, g] benzimidazole group. Group, benzopyrimidine group and the like. These groups may have the same substituents as described above.

In R ³⁶ , examples of the carboxyl group ester include methyl ester, ethyl ester, propyl ester and butyl ester. Specific examples of the coupler residue A represented by the above general formulas (a) to (g) include the following groups.

[0032]

[Chemical 9]

[0033]

[Chemical 10]

[0034]

[Chemical 11]

[0035]

[Chemical 12]

Specific examples of the azo compound include compounds represented by the following formulas (B1) to (B10).

[0037]

[Chemical 13]

[0038]

[Chemical 14]

[0039]

[Chemical 15]

In addition to the pigment represented by the general formula (1), the charge generating material has a purpose of expanding the sensitivity region of the electrophotographic photoreceptor so as to have an absorption wavelength region in a desired region. Therefore, other conventionally known charge generating materials can be used in combination. Other charge generating materials include selenium, selenium-tellurium, selenium-arsenic, amorphous silicon, pyrylium salts, azo pigments other than those represented by the general formula (1), perylene pigments, anthanthrone pigments, Examples thereof include phthalocyanine pigments, indigo pigments, triphenylmethane pigments, slene pigments, toluidine pigments, pyrazoline pigments, quinacridone pigments, and pyrrolopyrrole pigments. Charge Transport Material In the compounds represented by the general formulas (2) and (3),
An alkyl group corresponding to R2 to R14 in the formula, R2 and R in the formula
Examples of the aryl group corresponding to 8 include the same groups as those represented by the general formula (1).

Where R3, R4, R5, R6, R7, R
Examples of the halogen atom corresponding to 9, R10, R11, R12, R13, and R14 include fluorine, chlorine, bromine, and iodine. In the formula, R3, R4, R5, R6, R7, R9,
Examples of the alkoxy group corresponding to R10, R11, R12 and R13 include a methoxy group, an ethoxy group, an isopropoxy group, a butoxy group, a t-butoxy group and a hexyloxy group.

Specific examples of the compounds represented by the general formulas (2) and (3) include the compounds (A1) to (A20) as shown below.

[0043]

[Chemical 16]

[0044]

[Chemical 17]

[0045]

[Chemical 18]

The compounds represented by the above general formulas (2) and (3) can be synthesized by various methods. The compounds represented by the general formulas (2) and (3), which are charge transporting materials, can be used alone or in combination, and other conventionally known charge transporting materials can be used in combination. As the conventionally known charge transport material, various electron-withdrawing compounds and electron-donating compounds can be used.

Examples of the electron-withdrawing compound include 2,
^{6-dimethyl-2,, 6,} - di tert- dibutyl phenoxide diphenoquinone derivatives non like, malononitrile, thiopyran compounds, tetracyanoethylene, 2,
4,8-trinitrothioxanthone, 3,4,5,7-
Tetranitro-9-fluorenone, dinitrobenzene,
Examples include dinitroanthracene, dinitroacridine, nitroanthraquinone, dinitroanthraquinone, succinic anhydride, maleic anhydride, and dibromomaleic anhydride.

The electron donating compound is 2,5
-Oxadiazole compounds such as di (4-methylaminophenyl) and 1,3,4-oxadiazole, 9- (4
-Styryl compounds such as diethylaminostyryl) anthracene, carbazole compounds such as polyvinylcarbazole, pyrazoline compounds such as 1-phenyl-3- (p-dimethylaminophenyl) pyrazoline, hydrazone compounds, triphenylamine compounds, indole Compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds,
Examples thereof include nitrogen-containing cyclic compounds such as imidazole compounds, pyrazole compounds, and triazole compounds, and condensed polycyclic compounds.

These charge transport materials are used alone or in combination of two or more. When a charge transporting material having film-forming property such as polyvinylcarbazole is used,
The binder resin is not always necessary. Binder Resin Various resins can be used as the binder resin. For example, styrene-based polymer, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, acrylic copolymer, styrene-acrylic acid copolymer, polyethylene, ethylene-vinyl acetate copolymer , Chlorinated polyethylene, polyvinyl chloride, polypropylene, vinyl chloride-vinyl acetate copolymer, polyester alkyd resin, polyamide, polyurethane, polycarbonate, polyarylate, polysulfone, diallyl phthalate resin, ketone resin, polyvinyl butyral resin, polyether resin, Thermoplastic resin such as polyester resin, silicone resin, epoxy resin,
Examples thereof include phenol resins, urea resins, melamine resins, other crosslinkable thermosetting resins, and photocurable resins such as epoxy acrylate and urethane-acrylate.
These binder resins can be used alone or in combination of two or more. Additives The organic photosensitive layer may contain additives such as a sensitizer, a fluorene compound, an antioxidant, a deterioration inhibitor such as an ultraviolet absorber, and a plasticizer.

Further, in order to improve the sensitivity of the charge generating layer, known sensitizers such as terphenyl, halonaphthoquinones and acenaphthylene may be used in combination with the charge generating material. As the conductive substrate on which the organic photosensitive layer is formed, various conductive materials can be used, such as aluminum, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium and titanium. , Single metal such as nickel, palladium, indium, stainless steel, brass,
Examples include a plastic material obtained by vapor deposition or laminating of the above metal, glass coated with aluminum iodide, tin oxide, indium oxide, or the like.

The conductive substrate may be in the form of a sheet, a drum or the like, as long as the substrate itself has conductivity or the surface of the substrate has conductivity. Further, it is preferable that the conductive substrate has sufficient mechanical strength when used. Structure of Photoreceptor The photoconductor of the present invention can be applied to either a single layer type or a laminated type as a photosensitive layer. However, since the effect of the combination of the charge generating material and the charge transporting material becomes more remarkable especially in the single layer type photosensitive layer in which both materials are contained in the same layer, the present invention provides a single layer type photosensitive layer. It can be said that it is more preferable to apply to an electrophotographic photosensitive member having a layer.

To obtain a single-layer type photoreceptor, a compound represented by the general formula (1), which is a charge generating material, and a compound represented by the general formula (2), which is a charge transport material, A photosensitive layer containing a binder resin and the like may be formed on the conductive substrate by means such as coating. In order to obtain a laminated type photoreceptor, a charge generation layer containing the pigment represented by the general formula (1) is formed on a conductive substrate by means such as vapor deposition or coating. A charge transport layer containing the compound represented by the general formula (2) and a binder resin may be formed thereon. Alternatively, conversely to the above, the charge transport layer may be formed on the conductive substrate, and then the charge generation layer may be formed.

In the laminated photoreceptor, the charge generating material and the binder resin forming the charge generating layer can be used in various ratios, but to 100 parts of the binder resin (parts by weight, the same applies hereinafter). , Charge generating material 5 to 1000 parts, especially 30
It is preferably used at a ratio of about 500 parts. The charge transport material constituting the charge transport layer and the binder resin can be used in various proportions within a range that does not hinder the transport of charges and a range that does not crystallize, but they are generated in the charge generation layer by light irradiation. Binder resin 10 so that the accumulated electric charge can be easily transported.
10 parts to 500 parts, especially 25 parts of the charge transport material per 0 part.
It is preferably used in a proportion of about 200 parts.

The thickness of the laminated photosensitive layer is preferably 0.01 to 5 μm, particularly 0.1 to 3 μm for the charge generation layer, and 2 to 100 μm for the charge transport layer.
m, particularly preferably about 5 to 50 μm.
In a single-layer type photoreceptor, the charge generation material is 0.1 to 50 parts, particularly 0.5 to 30 parts, relative to 100 parts of the binder resin,
Suitably the charge transport material is 20 to 200 parts, especially 30 to 150 parts. The thickness of the single-layer type photosensitive layer is 5
The thickness is preferably about 100 to 100 μm, particularly about 10 to 50 μm.

In the case of a single-layer type photoreceptor, it is between the conductive substrate and the photosensitive layer, and in the case of the laminated type photoreceptor, it is between the conductive substrate and the charge generating layer, and the conductive substrate. A barrier layer may be formed between the charge transport layer and the charge transport layer or between the charge generation layer and the charge transport layer to the extent that the characteristics of the photoreceptor are not impaired. It may be formed. Preparation of Photoreceptor When forming each of the above layers by a coating method, the charge generation material, charge transport material, binder resin and the like exemplified above, together with a suitable solvent, in a known method, for example, a roll mill,
Prepare a coating solution by dispersing and mixing with a ball mill, attritor, paint shaker or ultrasonic disperser.
This may be applied and dried by a known means.

As the solvent for forming the coating solution, various organic solvents can be used, for example, alcohols such as methanol, ethanol, isopropanol and butanol,
Aliphatic hydrocarbons such as n-hexane, octane and cyclohexane, aromatic hydrocarbons such as benzene, toluene and xylene, halogenated hydrocarbons such as dichloromethane, dichloroethane, carbon tetrachloride and chlorobenzene, dimethyl ether, diethyl ether and tetrahydrofuran. Examples include ethers such as ethylene glycol dimethyl ether and diethylene glycol dimethyl ether, ketones such as acetone, methyl ethyl ketone and cyclohexanone, esters such as ethyl acetate and methyl acetate, dimethylformaldehyde, dimethylformamide and dimethyl sulfoxide. These solvents can be used alone or in combination of two or more.

Further, in order to improve the dispersibility of the charge transport material or the charge generating material and the smoothness of the surface of the photosensitive layer, a surfactant, a leveling agent, etc. may be used. Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. Examples 1 to 12 and Comparative Examples 1 to 6 (multilayer type photoreceptor) 1 part of the charge generating material, 1 part of polyvinyl butyral resin, and a predetermined amount of tetrahydrofuran were mixed in a paint shaker using glass beads (2 mm diameter). Dispersed for 2 hours. The obtained dispersion liquid was applied to the surface of an aluminum sheet as a conductive substrate by a bar coating method using a wire bar and dried at 100 ° C. for 1 hour to form a charge generation layer having a thickness of 0.5 μm. . The charge generating materials used are shown in Table 3 as the specific examples (B1) to (B1).
It is shown using the compound number of 0).

A solution prepared by dissolving 1 part of the charge transport material and 1 part of the bisphenol A type polycarbonate resin in a predetermined amount of dichloromethane was coated on the charge generation layer by a bar coating method using a wire bar, and the coating was carried out at 100 ° C. After drying for 1 hour, a charge transport layer having a film thickness of 22 μm was formed to obtain a negative charging type laminated electrophotographic photoreceptor. The charge transport materials used are the above-mentioned specific examples (A1) to (A) in the examples.
The compound numbers of 20) and Comparative Examples are represented by the following formula (D1).
It shows in Table 3 using the compound number of- (D11).

[0059]

[Chemical 19]

[0060]

[Chemical 20]

[0061]

[Chemical 21]

[0062]

Examples 13-24 and Comparative Examples 7-12
(Single-Layer Photoreceptor) 10 parts of a charge generating material, 75 parts of a charge transporting material, and 100 parts of a bisphenol A-type polycarbonate resin are dispersed together with a predetermined amount of dichloromethane for 2 hours using a paint shaker to form a single layer. A coating solution for the mold type photosensitive layer was prepared. Then, this coating solution is applied to the surface of an aluminum sheet as a conductive substrate by a bar coating method using a wire bar and dried at 100 ° C. for 1 hour to give a film thickness of 2
A single layer type photosensitive layer having a thickness of 5 to 30 μm was formed to obtain a positive charging type single layer type electrophotographic photosensitive member.

The charge generating material used is shown in Table 4
The compound numbers of the specific examples (B1) to (B10) described above are used, and the charge transport materials used are the compound numbers of the specific examples (A1) to (A20) described above with reference to Examples.
The comparative examples are shown using the compound numbers of the formulas (D1) to (D11). The following tests were carried out on the electrophotographic photoreceptors of the above-mentioned respective Examples and Comparative Examples, and their characteristics were evaluated. Electric characteristics By adjusting the flow-in current value by an electrostatic copying tester (Gentec Cynthia 30M manufactured by Gentec), the surface of the sheet-shaped electrophotographic photosensitive member prepared in Examples and Comparative Examples is adjusted to about ± 800V. After measuring the initial surface potential (V) at the time of charging, the most necessary 55 for the photoconductor for PPC.
The half-exposure amount was measured using 0 nm light. That is,
550n taken out from the xenon lamp using a spectrometer
m light was exposed with an intensity of 0.2 mW / cm ² and an exposure time of 1 second to obtain a half-exposure amount (μJ / cm ² ). Further, the surface potential at the time point when 0.5 seconds passed immediately after the exposure was determined as the post-exposure potential (V). Repetitive characteristics The electrophotographic photoreceptors obtained in each of the above Examples and Comparative Examples,
After sticking on each of the aluminum cylinders using an adhesive tape, they were mounted on an electrostatic copying machine DC-1670M (manufactured by Mita Industry Co., Ltd.).

Next, copying was repeated 10,000 times, and the electrophotographic photosensitive member was peeled from the aluminum cylinder at the initial stage and before and after repeating 10,000 times, and the surface potential (V) and half exposure amount ( μJ / c
m ² ), and the potential (V) after exposure was measured. The above results are shown in Table 1, Table 2 and Table 3.

[0066]

[Table 1]

[0067]

[Table 2]

[0068]

[Table 3]

As is clear from Tables 1, 2, and 3, the electrophotographic photosensitive members of the present invention represented by Examples 1 to 24 are
It can be seen that it has excellent post-exposure potential, half-exposure amount and repetitive characteristics, and exhibits high performance as electrophotographic characteristics. On the other hand, the electrophotographic photosensitive members represented by Comparative Examples 1 to 12 had high post-exposure potential and poor sensitivity. Therefore, fog has occurred from the beginning of copying, and even if the exposure lamp, which is standardly installed in the electrostatic copying machine, outputs at maximum, the potential corresponding to the white background is high and fog occurs.

Further, as is clear from Table 5, the electrophotographic photosensitive members of Comparative Examples 1, 4, 6, 7, 8, and 12 had a surface potential extremely lowered by repeated use.
Therefore, in the image confirmation after repeated copying, the contrast potential was reduced and the image density was also reduced.

[0071]

According to the present invention, the azo pigment represented by the general formula (1) as the charge generating material is replaced by the compound represented by the general formula (2) or (3) as the charge transporting material. By selecting, it was possible to provide an organic photoreceptor having excellent electrophotographic characteristics.

Claims (1)

[Claims] 1. The following general formula (1) as a charge generating material on a conductive substrate: (In the formula, A is the same or different and represents a coupler residue, R 1 represents a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group. The alkyl group, the aryl group, and the heterocyclic group represent a substituent. Bisazo pigment represented by the following general formula (2) or (3) as a charge transporting material: (In the formula, R2 represents a hydrogen atom, an alkyl group or an aryl group, and R3 represents a hydrogen atom, an alkyl group, an alkoxy group,
Indicates a halogen atom or amino group, R4, R5, R6, R
7 represents a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom, and p represents an integer of 0 to 2. ) [Chemical 3] (In the formula, R8 represents a hydrogen atom, an alkyl group or an aryl group, and R9 represents a hydrogen atom, an alkyl group, an alkoxy group,
Indicates a halogen atom or amino group, R10, R11, R1
2, R13 is a hydrogen atom, an alkyl group, an alkoxy group,
A halogen atom is shown, R14 shows a hydrogen atom, an alkyl group, a halogen atom, and an amino group, r shows the integer of 0-2, q shows the integer of 1-2. An electrophotographic photosensitive member comprising a photosensitive layer containing a compound represented by the formula (1).