JPH0683087A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To provide an electrophotographic sensitive body having high sensitivity and excellent it durability. CONSTITUTION:A photosensitive layer contg. an azo compd. represented by the formula is formed on an electric conductive substrate. In the formula, each of A<1> and A<2> is a residue of a coupler, A<1> and A<2> may be different from each other, each of R<1> and R<2> is H, alkyl or alkoxy, each of R<3> and R<4> is H, halogen, alkyl or aryl and each of (m) and (n) is 0 or 1.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an electrophotographic photoreceptor,
More specifically, the present invention relates to an electrophotographic photosensitive member used in an electrostatic copying machine, a laser beam printer or the like.

[0002]

2. Description of the Related Art The Carlson process is widely used to form a copied image using an electrophotographic photosensitive member. The Carlson process consists of a charging process that uniformly charges the photoconductor by corona discharge, an exposure process that exposes the charged photoconductor to the original image to form an electrostatic latent image corresponding to the original image, and an electrostatic latent image. A developing step of developing with a developer containing toner to form a toner image, a transfer step of transferring the toner image to a base material such as paper, a fixing step of fixing the toner image transferred to the base material, and a transfer step. After the step, a cleaning step of removing the toner remaining on the photoconductor is included.

In order to form a high quality image in the Carlson process, the electrophotographic photosensitive member is required to have excellent charging characteristics and photosensitive characteristics and to have a low residual potential after exposure. Conventionally, inorganic photoconductors such as selenium and cadmium sulfide have been known as electrophotographic photosensitive materials, but they are toxic and are not desirable because of high production cost.

Therefore, so-called organic electrophotographic photoconductors using various organic substances, which are excellent in workability and advantageous in terms of manufacturing cost and have a high degree of freedom in functional design, in place of these inorganic substances. Is proposed. Such an organic electrophotographic photoreceptor usually has a photosensitive layer composed of a charge generating material that generates a charge upon exposure and a charge transporting material that has a function of transporting the generated charge.

In order to satisfy various conditions desired for such an organic electrophotographic photosensitive member, it is necessary to appropriately select these charge generating material and charge transporting material. As the charge generation material, many compounds such as phthalocyanine compounds, perylene compounds, quinacridone compounds, ansanthrone compounds, azo compounds have been proposed. For example, as azo compounds, those disclosed in JP-A-47-37543 and JP-A-57-195767 are known.

[0006]

However, the above-mentioned conventional charge generating materials have the problems that the photosensitive wavelength region is narrow, the sensitivity is low, or the photostability is insufficient. The photoconductor containing the generating material was also inferior in sensitivity and durability. The present invention solves the above problems, and an object of the present invention is to provide an electrophotographic photoreceptor having excellent characteristics such as high sensitivity and excellent durability.

[0007]

The electrophotographic photoreceptor of the present invention for solving the above-mentioned problems contains an azo compound represented by the following general formula (I) on a conductive substrate. It is characterized in that a photosensitive layer is provided.

[0008]

[Chemical 5]

[Wherein A ¹ and A ² represent the same or different coupler residues, R ¹ and R ² represent the same or different hydrogen atoms, alkyl groups or alkoxy groups, and R ³ and
R ⁴ is the same or different and represents a hydrogen atom, a halogen atom, an alkyl group or an aryl group. m and n are 0 or 1
Indicates. According to the studies of the present inventors, the azo compound represented by the general formula (I) has high sensitivity and does not cause a significant decrease in surface potential due to repeated use. Also, since the residual potential is low,
Excellent stability against repeated exposure,
It is capable of stably maintaining high sensitivity to long-term exposure and exposure at high temperatures, and has excellent light stability. Therefore, the electrophotographic photosensitive member of the present invention having a photosensitive layer containing the azo compound has high sensitivity and excellent durability.

The present inventors presume the reason why the azo compound has such high sensitivity and photostability as follows. That is, the azo compound represented by the general formula (I) is caused by the peculiar structure of the dithio (3,3) metacyclophane introduced in the molecule, and is described in, for example, JP-A-47-37543. Illustrative general formula (II) below:

[0011]

[Chemical 6]

[Wherein A ¹ and A ² represent the same coupler residue as described above, Y represents a hydrogen atom, a methyl group, a methoxy group,
Indicates an ethoxy group, hydroxyl group, chlorine atom or bromine atom]
Alternatively, the following general formula (III) exemplified in JP-A-54-46558:

[0013]

[Chemical 7]

A conventional bisazo compound represented by the formula [wherein A ¹ and A ² represent the same coupler residue as described above and R represents a hydrogen atom, an ethyl group, a chloroethyl group or a hydroxyethyl group] It is presumed that this is because the carrier generation ability during light irradiation is superior. The above general formula
The azo compound represented by (I) is basically represented by the following general formula
It contains an azo compound represented by (Ia) to (Ic).

[0015]

[Chemical 8]

[A in the formula¹, A², R¹, R², R³, R
^FourRepresents the same group as described above. ] The azo compounds represented by the above general formulas (I) and (Ia) to (Ic)
In the thing, R¹, R ²Of these, as an alkoxy group,
Examples include methoxy group and ethoxy group.
Examples of the kill group include a methyl group and an ethyl group.
You can Also R³, R^FourOf these, as an alkyl group,
For example, methyl group, ethyl group, propyl group, isopropyl group
Group, butyl group, isobutyl group, t-butyl group, pliers
Group, hexyl group, etc., and as an aryl group
Is, for example, a phenyl group, a noryl group, a xylyl group, a bif
Phenyl group, naphthyl group, etc.
For example, chlorine atom, bromine atom, iodine atom, fluorine,
Examples include fluorine atoms.

Examples of the coupler residues A ¹ and A ² include groups represented by the following general formulas (a) to (g). The coupler residues A ¹ and A ² may be the same or different from each other.

[0018]

[Chemical 9]

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 include 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, a carbonyl group, a carboxyl group and the like. It may have a substituent.

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 following formula (h) in the above general formulas (e) and (f).

[0022]

[Chemical 10]

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.
As the alkyl group, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group,
Examples thereof include lower alkyl groups having 1 to 6 carbon atoms such as tert-butyl group, pentyl group and hexyl group.

Examples of the aryl group include phenyl group, tolyl group, xylyl group, biphenyl group, naphthyl group, anthryl group and phenanthryl group. Examples of the alkenyl group include lower alkenyl groups having 2 to 6 carbon atoms such as vinyl group, allyl group, 2-butenyl group, 3-butenyl group, 1-methylallyl group, 2-pentenyl group and 2-hexenyl group. To be

Examples of the halogen atom include chlorine atom, bromine atom, iodine atom and fluorine atom. 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 includes, for example, an alkylene group such as a methylene group, an ethylene group, a propylene group and a butylene group. To be

The aromatic ring formed by 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.

Examples of the polycyclic hydrocarbon formed by the condensation of R ³¹ with R ³⁰ and a benzene ring having a hydroxyl group include a carbazole ring, a benzocarbazole ring and a dibenzofuran ring. Further, in R ³¹ , an atomic group necessary for forming a heterocycle by condensing with R ³⁰ and a benzene ring having a hydroxyl group is, for example, a benzofuranyl group, a benzothiophenyl group, an indolyl group, a 1H-indolyl group, bezoxazolyl. Group, benzothiazolyl group, 1H-indaryl 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 condensing R ³¹ with R ³⁰ and a benzene ring having a hydroxyl group include, for example, thienyl group, furyl group, pyrrolyl group,
Oxazolyl group, isoxazolyl group, thiazolyl group,
Examples thereof include isothiazolyl group, imidazolyl group, pyrazolyl group, triazolyl group, tetrazolyl group, pyridyl group and thiazolyl group. Further, it may 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, etc.).

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

[0033]

[Chemical 11]

[0034]

[Chemical 12]

[0035]

[Chemical 13]

[0036]

[Chemical 14]

The azo compound represented by the general formula (I) can be synthesized by various methods. For example, taking the azo compound represented by the general formula (Ia) as an example, first, as shown in the following reaction process formula, bis (chloromethyl) benzene compound (1) and bis (mercaptomethyl) By reacting the benzene compound (2) with a base such as potassium hydroxide, a dithio (3,3) metacyclophane compound represented by the general formula (3) is produced.

[0038]

[Chemical 15]

Next, the above compound is nitrated by a conventional method to obtain a dinitro-dithio (3,3) metacyclophane compound represented by the following general formula (4), which is reduced by a conventional method. A diamino-dithio (3,3) metacyclophane compound (general formula (5)) is prepared. And this diamino-dithio (3,3) metacyclophane compound
The two amino groups of (5) are each diazotized to form a tetrazonium salt, which is coupled with a predetermined coupler in an organic solvent to produce an azo compound represented by the general formula (Ia). The diazotization is carried out by adding sodium nitrite or nitrous acid dropwise at a low temperature (usually -10 to 10 ° C) while stirring an acidic aqueous solution of diamino-dithio (3,3) metacyclophane compound (5). Done.

[0040]

[Chemical 16]

[A ¹ , A ² in the above reaction process formulas,
R ¹ and R ² represent the same groups as described above. In the electrophotographic photosensitive member of the present invention, the above-mentioned azo compound can be used alone as a charge generating material, or can be used in combination with other conventionally known charge generating materials. Other charge generating materials include, for example, amorphous silicon, pyrylium salts, anthanthrone pigments, phthalocyanine pigments, indigo pigments, triphenylmethane pigments, slene pigments, toluidine pigments, pyrazoline pigments, perylene pigments. , And quinacridone pigments.

These charge generating materials are used alone or in combination of two or more so as to have an absorption wavelength region in a desired region. The constitution of the present invention can be applied to both so-called single-layer type and laminated type electrophotographic photoreceptors. In order to obtain a single-layer type photoreceptor, a photosensitive layer containing a charge generating material, an azo compound represented by the general formula (I), a charge transporting material, a binder resin, etc. is applied. It may be formed on the conductive substrate by means.

In order to obtain a laminated type photoreceptor, a charge generating layer containing the above azo compound as a charge generating material is formed on a conductive base material by means of coating or the like, and this charge generating layer is formed. A charge transport layer containing a charge transport material and a binder resin may be formed thereover. On the contrary to the above, a charge transport layer similar to the above is formed on a conductive substrate, and then a charge generating layer containing the azo compound as a charge generating material is formed by means of coating or the like. Good. further,
The charge generation layer may be formed by dispersing a charge generation material and a charge transport material in a binder resin and coating the resin.

As the charge-transporting material, conventionally known materials can be used, for example, oxadiazole compounds such as 2,5-di (4-methylaminophenyl) -1,3,4-oxadiazole. , Styryl compounds such as 9- (4-diethylaminostyryl) anthracene, carbazole compounds such as polyvinylcarbazole, pyrazoline compounds such as 1-phenyl-3- (p-dimethylaminophenyl) pyrazoline, hydrazone compounds, triphenyl Amine-based compounds, indole-based compounds, oxazole-based compounds, isoxazole-based compounds, thiazole-based compounds, thiadiazole-based compounds, imidazole-based compounds, pyrazole-based compounds, nitrogen-containing cyclic compounds such as triazole-based compounds, fused polycyclic compounds can give.

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. Further, as the binder resin used in the single-layer type or laminated type photoreceptor,
Various resins can be used, for example, a styrene polymer, a styrene-butadiene copolymer, a styrene-acrylonitrile copolymer, a styrene-maleic acid copolymer, an acrylic polymer, a styrene-acrylic copolymer. , Polyethylene, ethylene vinyl acetate copolymer, chlorinated polyethylene, polyvinyl chloride, polypropylene, vinyl chloride-vinyl acetate copolymer, polyester, alkyd resin, polyamide, polyurethane, polycarbonate, polyarylate, polysulfone, diallylphthalate 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, urethane-a Various polymers such as photocurable resins such relations and the like.

These binder resins may be used either individually or in combination of two or more. A solvent is used when the charge generation layer and the charge transport layer are formed by a coating method or the like. As this solvent, 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,
Benzene, toluene, aromatic hydrocarbons such as xylene, dichloromethane, dichloroethane, carbon tetrachloride, halogenated hydrocarbons such as chlorobenzene, dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, ethers such as diethylene glycol dimethyl ether, acetone, methyl ethyl ketone, Examples thereof include ketones such as cyclohexanone, esters such as ethyl acetate and methyl acetate, and various solvents such as dimethylformaldehyde, dimethylformamide and dimethylsulfoxide.

These solvents may be used alone or in combination of two or more. In order to improve the sensitivity of the charge generation layer, known sensitizers such as terphenyl, halonaphthoquinones and acenaphthylene may be used together with the charge generation material. Further, a surfactant, a leveling agent, etc. may be used to improve the dispersibility of the charge transport material or the charge generating material, the dyeing property and the like.

As the conductive base material, various conductive materials can be used. For example, simple metals such as aluminum, copper, tin, platinum, gold, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel, and brass,
Examples thereof include a plastic material obtained by vapor deposition or laminating of the above metal, glass coated with aluminum iodide, tin oxide, indium oxide and the like.

The conductive base material may be in the form of a sheet or a drum, as long as the base material itself is conductive or the surface of the base material is conductive. As the base material, a base material having sufficient mechanical strength when used is preferable. Each of the single-layer type and multi-layer type organic photosensitive layers may contain additives such as sensitizers, fluorene compounds, antioxidants, deterioration inhibitors such as ultraviolet absorbers, and plasticizers.

The amount of the charge transport material added to the single-layer type photosensitive layer is suitably 40 to 200 parts by weight, preferably 50 to 100 parts by weight, based on 100 parts by weight of the binder resin. Further, the addition amount of the charge transport material in the laminated charge transport layer is 10 to 100 parts by weight of the binder resin.
Suitably 500 parts by weight, preferably 25 to 200 parts by weight.

The addition amount of the charge generating material in the single-layer type photosensitive layer is appropriately 0.1 to 50 parts by weight, preferably 0.5 to 30 parts by weight, based on 100 parts by weight of the binder. is there. Further, the addition amount of the charge generating material in the laminated charge generating layer is 5 to 5 parts by weight with respect to 100 parts by weight of the binder resin.
Suitably, the amount is 00 parts by weight, preferably 10 to 300 parts by weight.

The thickness of the photosensitive layer formed is preferably about 5 to 100 μm in the case of a single layer type, and more preferably about 10 to 50 μm. On the other hand, in the case of a laminated type, the thickness of the charge generation layer is about 0.01 to 5 μm, preferably 0.1 to 5 μm.
About 3 μm, the thickness of the charge transport layer is about 2 to 100 μm,
It is preferably about 5 to 50 μm. Further, in the case of a single-layer type electrophotographic photoreceptor, between the base material and the photosensitive layer, and in the case of a laminated type electrophotographic photoreceptor, between the base material and the charge generation layer. A barrier layer may be formed between the base material and the charge transport layer and between the charge generation layer and the charge transport layer to the extent that the characteristics of the photoreceptor are not impaired. A layer may be formed.

When the charge generation layer and the charge transport layer are formed by a coating method, the charge generation material and the binder resin may be formed by a known method such as roll mill, ball mill, attritor, paint shaker or ultrasonic wave. It may be prepared by dispersing and mixing using a disperser or the like, and applying and drying this by a known means. As described above, the charge generation layer may be formed by depositing the above charge generation material.

[0054]

[Examples] The present invention will be described below based on Examples and Comparative Examples.
Explain the Ming.Example 1 As the charge generation material, R in the general formula (Ia) is used.¹, R²But
Both are methoxy groups, A ¹, A²Are both represented by the above formula (A1)
Is a coupler residue that is represented by the following formula:
The following procedures can be used to produce monolayer and
A layer type photoreceptor was prepared.

[0055]

[Chemical 17]

(Preparation of Single Layer Type Photoreceptor) 8 weight of bisazo compound as charge generating material and the following formula as charge transporting material:

[0057]

[Chemical 18]

N, N, N ', N'-tetrakis (3-methylphenyl) -m-phenylenediamine 1 represented by
00 parts by weight and polycarbonate 10 as a binder resin
0 parts by weight together with a predetermined amount of tetrahydrofuran,
A single layer type photosensitive layer coating liquid was prepared by mixing and dispersing using a ball mill. Apply this coating liquid to a diameter of 80 mm x length of 350 mm
Drum type positive charging type electrophotographic photoconductor having a single-layer type photosensitive layer having a film thickness of 24 μm after being coated on the surface of the aluminum base tube by a dipping method and then dried by heating at 100 ° C. for 30 minutes in a dark place. The body was made.

(Production of Laminated Photoreceptor) 100 parts by weight of polyvinyl butyral as a binder resin, 100 parts by weight of a bisazo compound as a charge generating material, and a predetermined amount of tetrahydrofuran were charged in a ball mill and mixed with stirring for 24 hours. Then, a charge generation layer coating liquid was prepared. This coating solution is applied to the surface of an aluminum tube having a diameter of 80 mm and a length of 350 mm by a dipping method, and then, in a dark place, 11
Dry with hot air for 30 minutes at 0 ° C and cure to a film thickness of 0.5μ
m charge generating layer was formed.

Next, 100 parts by weight of polycarbonate as a binder resin and N, N, and N as a charge transport material are used.
N ', N'-tetrakis (3-methylphenyl) -m-
100 parts by weight of phenylenediamine and a predetermined amount of toluene were mixed by stirring with a homomixer to prepare a charge transport layer coating solution. This coating solution is applied onto the charge generation layer previously formed on the surface of the raw tube by a dipping method, and dried by hot air at 90 ° C. for 30 minutes to form a charge transport layer having a thickness of about 20 μm, and laminated. A drum type negative charging type electrophotographic photosensitive member having a mold photosensitive layer was produced.

[0061]Example 2 As the charge generation material, R in the general formula (Ia) is used.¹, R²But
Both are methoxy groups, A ¹, A²Are both represented by the above formula (A2)
Bisazo compound which is a coupler residue
Except for the above, in the same manner as in Example 1 above, the single layer type and
And a laminated type photoconductor were produced.

[0062]Example 3 As the charge generation material, R in the general formula (Ia) is used.¹, R²But
Both are methoxy groups, A ¹, A²Are both represented by the above formula (A3)
Bisazo compound which is a coupler residue
Except for the above, in the same manner as in Example 1 above, the single layer type and
And a laminated type photoconductor were produced.

[0063]Example 4 As the charge generation material, R in the general formula (Ia) is used.¹, R²But
Both are methoxy groups, A ¹, A²Are both represented by the above formula (A9)
Bisazo compound which is a coupler residue
Except for the above, in the same manner as in Example 1 above, the single layer type and
And a laminated type photoconductor were produced.

[0064]Example 5 As the charge generation material, R in the general formula (Ia) is used.¹, R²But
Both are methoxy groups, A ¹, A²Are both in the above formula (A12)
Uses a bisazo compound that is a coupler residue represented
A single layer type was prepared in the same manner as in Example 1 except for the above.
And a laminated type photoconductor were produced.

[0065]Example 6 As the charge generation material, R in the general formula (Ia) is used.¹, R²But
Both are methoxy groups, A ¹, A²Are both in the above formula (A14)
Uses a bisazo compound that is a coupler residue represented
A single layer type was prepared in the same manner as in Example 1 except for the above.
And a laminated type photoconductor were produced.

[0066]Example 7 As the charge generation material, R in the general formula (Ia) is used.¹, R²But
Both are methoxy groups, A ¹, A²Are both in the above formula (A19)
Uses a bisazo compound that is a coupler residue represented
A single layer type was prepared in the same manner as in Example 1 except for the above.
And a laminated type photoconductor were produced.

[0067]Example 8 As the charge generation material, R in the general formula (Ib) is used.¹, R²But
Both are methoxy groups, R ³Is a hydrogen atom, A¹, A²With
Is bisazo which is a coupler residue represented by the formula (A2).
The same as in Example 1 except that a system compound was used.
Then, single-layer type and laminated type photoconductors were produced.

[0068]Example 9 As the charge generating material, R in the general formula (Ic) is used.¹, R²But
Both are methoxy groups, R ³, R^FourAre both hydrogen atoms,
A¹, A²Is the coupler residue represented by the above formula (A2).
Other than using a bisazo compound that is a group,
In the same manner as in Example 1, single-layer type and multilayer type photoreceptors were prepared.
It was made.

Comparative Example 1 As the charge generating material, the following formula:

[0070]

[Chemical 19]

Single-layer type and multi-layer type photoconductors were prepared in the same manner as in Example 1 except that chlorodian blue represented by the following formula was used. The following tests were carried out on the electrophotographic photosensitive members of the above Examples and Comparative Examples to evaluate their characteristics. Measurement of Initial Surface Potential Each electrophotographic photosensitive member is loaded into an electrostatic copying tester (Gentec Cynthia 30M, trade name, manufactured by Gentech Co., Ltd.), and the surface thereof is positively or negatively charged to obtain an initial surface potential Vs. .p. (V) was measured.

Measurement of Half-Exposure Amount and Residual Potential The electrophotographic photosensitive member charged in the above-mentioned measurement of the initial surface potential was exposed at an exposure intensity of 10 lux by using a halogen lamp as an exposure light source of an electrostatic copying tester. Exposure under the conditions,
The time until the surface potential became 1/2 was calculated, and the half-exposure amount E1 / 2 (lux.sec) was calculated.

The surface potential was measured at 0.15 seconds after the above exposure was started, and the residual potential V1r.p. (V) was measured.
And Measurement of Light Stability The electrophotographic photosensitive member was loaded in an electrostatic copying machine (Model DC-1657 manufactured by Mita Kogyo Co., Ltd.) to continuously copy 1000 sheets, and then repeatedly exposed in the same manner as above. The residual potential V2r.p. (V) after that was measured. Then, the difference ΔVr.p. (V) between the residual potentials V1r.p. and V2r.p. was obtained.

The above results are shown in Table 1.

[0075]

[Table 1]

From the results shown in Table 1, the residual potential V1r.p of the electrophotographic photosensitive members of Examples 1 to 9 having the constitution of the present invention is higher than that of Comparative Example 1, regardless of whether it is a single layer type or a laminated type. Is low,
Moreover, since the half-dose exposure amount E1 / 2 was small, it was found that the sensitivity characteristics were excellent. Further, the above Examples 1 to 9
Since ΔVr.p. was smaller than that of Comparative Example 1, it was found that each of them had excellent durability.

[0077]

INDUSTRIAL APPLICABILITY As described above, the electrophotographic photoreceptor of the present invention is provided with a photosensitive layer containing a specific azo compound having high sensitivity and photostability, and therefore has high sensitivity and It has excellent durability.

Claims (4)

[Claims] 1. On a conductive substrate, a compound of the general formula (I): [Wherein A ¹ and A ² represent the same or different coupler residues, R ¹ and R ² represent the same or different hydrogen atom, alkyl group or alkoxy group, and R ³ and R ⁴ represent the same or different hydrogen. An atom, a halogen atom, an alkyl group or an aryl group is shown. m and n represent 0 or 1. ] An electrophotographic photoreceptor provided with a photosensitive layer containing an azo compound represented by 2. An azo compound is represented by the general formula (Ia): [In the formula, A ¹ , A ² , R ¹ and R ² represent the same groups as described above. ] The electrophotographic photosensitive member according to claim 1, represented by: 3. An azo compound is represented by the general formula (Ib): [Wherein A ¹ , A ² , R ¹ , R ² and R ³ represent the same groups as described above. ] The electrophotographic photosensitive member according to claim 1, represented by: 4. An azo compound is represented by the general formula (Ic): [In the formula, A ¹ , A ² , R ¹ , R ² , R ³ and R ⁴ represent the same groups as described above. ] The electrophotographic photosensitive member according to claim 1, represented by: