JPH05150499A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To provide the photosensitive body having high sensitivity and excellent durability by providing a photosensitive layer contg. a specific azo compd. on a conductive base material. CONSTITUTION:The photosensitive layer contg. the azo compd. expressed by formula is provided on the conductive base material. In the formula, (m) and (n) respectively independently denote 1 or 2; R<1> denotes a hydrogen atom, halogen atom, alkyl group, sulfoxide group, etc.; A denotes a coupler residue without having a donor property. Since the bisazo pigment expressed by the formula is formed by fixing the core part and the coupler residue part exhibiting the donor property and introducing the coupler residue having an acceptor type substituent into another coupler residue, a deviation in the electron density distribution of the molecule is generated, by which the improved sensitivity is obtd. Namely, the polarization of the molecule in the excited state is increased by the deviation in the electron density distribution of the molecules, by which the improved charge generating efficiency by the intensity of the internal polarization of the pigment and the improved efficiency of implanting carriers into the charge transfer material are obtd.

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 provided with an organic photosensitive layer on a conductive substrate, and more specifically, to an electrophotographic photosensitive member having high sensitivity and excellent repeatability over the entire visible light region. Regarding the body

[0002]

2. Description of the Related Art An organic photoconductor for electrophotography has a charge generation function and a charge transport function by using a charge generation material that generates a charge by light irradiation and a charge transport material that transports the generated charge. There is a so-called function-separated type that separates and. The function-separated type photoconductor includes a single layer type in which a photosensitive layer containing a charge generating material and a charge transporting material is formed on a conductive substrate, and a charge generating layer containing a charge generating material in a conductive substrate. And a charge transport layer containing a charge transport material is further laminated, or a charge generation layer in which the order of lamination is reversed.

As the above-mentioned charge generating material, conventionally,
Indigo pigments, perylene pigments, carbazole-based disazo pigments, oxazole-based disazo pigments and the like are used. However, since the above indigo pigment has a low charge generation efficiency, when this material is used as a charge generation material for an electrophotographic photosensitive member, the sensitivity is poor, and the photosensitive wavelength region is narrow, or near infrared rays are generated. Many of them have strong absorption in a region, and there are drawbacks that sensitivity is low over the entire visible light region and repeatability is poor. For this reason, it cannot be used, for example, as a photoreceptor for forming a color image.

Therefore, the present applicant proposed an electrophotographic photoreceptor containing a new azo compound in order to solve the above problems. (Japanese Patent Application No. 3-238395)

[0005]

However, as a result of intensive studies by the present inventors, the inventors found that the bias of the electron density distribution greatly affects the improvement of the charge generation rate and the repetition stability.

Therefore, the present invention has higher sensitivity,
It is also an object of the present invention to provide an excellent electrophotographic photosensitive member having improved characteristics such as excellent durability.

[0007]

In order to solve the above-mentioned problems, the electrophotographic photoreceptor of the present invention 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 2]

(In the formula, m and n are independently 1
Or 2 represents, R ¹ represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, an amino group, a cyano group, a nitro group or a sulfoxide group, and A represents a coupler residue having no donor property. . ) According to the studies by the present inventors, the bisazo pigment represented by the general formula (I) is
Formula (II) below

[0010]

[Chemical 3]

A core portion having a small I effect represented by the following formula (III)

[0012]

[Chemical 4]

The coupler residue portion having a strong donor property represented by is fixed, and the coupler residue having an acceptor substituent is introduced into A as the other coupler residue. , The electron density distribution of the molecules is biased, and the sensitivity is remarkably improved. That is, the polarization of the molecule in the excited state becomes large due to the bias of the electron density distribution of the molecule, the charge generation efficiency is improved by the strength of the internal polarization of the pigment, and the charge transport material is enhanced by the interaction with the charge transport material. It is possible to improve the efficiency of carrier injection into.

The azo compound represented by the above general formula (I) basically contains a bisazo compound represented by the following general formula (Ia).

[0015]

[Chemical 5]

(In the formula, R ¹ represents the same group as described above, and A represents the same coupler residue as described above.) In the azo compound represented by the general formula (I), the coupler residue having no donor property is used. Examples of the group A include groups represented by the following general formulas (a) to (f).

[0017]

[Chemical 6]

In the above coupler residue, R ⁵ is a hydroxyl group, —NR ¹¹ R ¹² (in the formula, R ¹¹ and R ¹² each independently represents a hydrogen atom or an alkyl group) or —N.
HSO ₂ R ¹³ (in the formula, R ¹³ represents a hydrogen atom or an alkyl group, an alkenyl group or an aryl group).

R ⁶ represents a hydrogen atom, a halogen atom, a carboxyl group, an alkoxycarbamoyl group, a carbamoyl group or a sulfamoyl group, and the sulfamoyl group is a halogen atom, a phenyl group, a naphthyl group, a carbonyl group,
It may have a substituent such as a carboxyl group.

R ⁷ represents an atomic group necessary for being condensed with a benzene ring having R ⁵ and R ⁶ to form an aromatic ring or an aliphatic or heterocyclic ring, and these rings have the same substituents as described above. May have.

R ⁹ represents a hydrogen atom, an alkyl group or an aryl group, and the alkyl group or the aryl group may have the same substituent as described above. R ¹⁰ represents a phenylene group or a naphthylene group, and these may have the same substituents as described above.

Examples of the alkyl group include alkyl groups having 1 to 6 carbon atoms such as methyl, ethyl, propyl, isobutyl, pentyl and hexyl. Examples of the alkenyl include alkenyl groups having 2 to 6 carbon atoms such as vinyl, allyl, 2-butenyl, 3-butenyl, 1-methylallyl, 2-penitenyl and 2-hexenyl. Examples of the halogen atom include fluorine, chlorine, bromine and iodine.

In R ⁷ , the atomic group which is condensed with the benzene ring having R ⁵ and R ⁶ to form an aliphatic ring has 1 to 4 carbon atoms such as methylene group, ethylene group, propylene group and butylene group. The alkylene groups of In R ⁷ , the heterocycle formed by condensation with the benzene ring having R ⁵ and ⁶ includes benzofuranyl, benzothiophenyl, benzoxazolyl, benzothiazolyl, 1H-indazolyl, chromenil, chromanyl, isochromanyl, dibenzofuranyl. And nil, xanthenyl, acridinyl, phenanthridinyl, phenanthinyl, phenaxazinyl, thianthrenyl and the like.

Specific examples of the coupler residue A represented by the above general formulas (a) to (f) include the groups represented by A1 to A2, which have extremely weak acceptor properties, and the weak acceptor properties. Examples thereof include the groups represented by B1 to B2, the groups represented by C1 to C2 exhibiting a strong acceptor property, and the groups represented by D1 to D2 exhibiting an extremely strong acceptor property.

[0025]

[Chemical 7]

The azo compound of the present invention represented by the above general formula (I) can be synthesized by various methods via the diazonium salt represented by the following general formula (IV) as an intermediate.

[0027]

[Chemical 8]

(In the formula, X is a hydrohalic acid such as hydrochloric acid,
Indicates anions of borofluoric acid, hydrobromic acid, sulfuric acid, nitric acid, perchloric acid and other acids. ) For example, it can be easily manufactured by the method described below.

0.002 mol of tetrazonium difluoroborate represented by the formula (IV) and 0.002 mol of the coupler represented by the formula (III) were dissolved in 100 ml of N, N-dimethylformamide, and sodium acetate 0 .002m
ol dissolved in 5 ml of water is added dropwise over 5 minutes while maintaining the liquid temperature at 17 ° C to 21 ° C. Then, after stirring for 3 hours, 0.002 mol of a coupler represented by HA (A is a coupler residue in the general formula (I)) was added, and 0.002 mol of sodium acetate was dissolved in 5 ml of water. Dropwise as before and then stir for an additional 3 hours.

The precipitate formed is filtered off, washed 5 times with 200 ml of N, N-dimethylformamide and then 20 times of water.
The azo compound of the present invention can be obtained by washing with 0 ml three times and then drying under reduced pressure.

The electrophotographic photosensitive member of the present invention is constituted by providing an organic photosensitive layer containing a bisazo compound represented by the general formula (I) as a charge generating material on a conductive substrate. The organic photosensitive layer may be a single layer or a plurality of layers (for example, a charge generation layer and a charge transport layer). Furthermore, a protective layer may be provided on the organic photosensitive layer, and an intermediate layer may be provided between the organic photosensitive layer and the conductive substrate. The bisazo compound may be used alone or in combination of two or more.

In the present invention, in addition to the bisazo compound represented by the general formula (I), a charge generating material may be contained, for example, selenium, selenium-tellurium, amorphous silicon, pyrylium salt, and conventionally known compounds. Bisazo compounds, anthanthrone compounds, phthalocyanine compounds, indigo compounds, triphenylmethane compounds,
Examples thereof include threnic compounds, toluidine compounds, pyrazolyl compounds, perylene compounds, and quinacridone compounds.

Further, the organic photosensitive layer may contain a charge transport material. Examples of such charge transport materials include m-phenylenediamine compounds; tetracyanoethylene; fluorenone compounds such as 2,4,7, -trinitro-9-fluorenone; nitrated compounds such as dinitroanthracene; anhydrous amber. Acid; maleic anhydride; dibromomaleic anhydride; triphenylmethane compound; 2,5-di (4-dimethylaminophenyl)-
Oxadiazole compounds such as 1,3,4-oxadiazole; styryl compounds such as 9- (4-diethylaminostyryl) anthracene; carbazole compounds such as poly-N-vinylcarbazole; 1-phenyl-3 −
Pyrazoline compounds such as (p-dimethylaminophenyl) pyrazoline; 4,4 ′, 4 ″,-tris (N, N-)
Amine derivatives such as diphenylamino) triphenylamine; 1,1-bis (4-diethylaminophenyl)-
Conjugated unsaturated compounds such as 4,4-diphenyl-1,3-butadiene; hydrazone compounds such as 4- (N, N-diethylamino) benzaldehyde-N, N-diphenylhydrazone; indole compounds, oxazole compounds, iso Oxazole compounds, thiazole compounds,
Examples thereof include nitrogen-containing cyclic compounds such as thiadiazole compounds, imidazole compounds, pyrazole compounds, pyrazoline compounds, and triazole compounds; condensed polycyclic compounds and the like.

The following compounds are exemplified as the m-phenylenediamine compound. N, N, N ',
N'-tetraphenyl-1,3-phenylenediamine,
N, N, N ', N'-tetrakis (3-tolyl) -1,
3-phenylenediamine, N, N, N ', N'-tetraphenyl-3,5-tolylenediamine, N, N, N',
N'-tetrakis (3-tolyl) -3,5-tolylenediamine, N, N, N ', N'-tetrakis (4-tolyl) -1,3-phenylenediamine, N, N, N',
N'-tetrakis (4-tolyl) -3,5-tolylenediamine, N, N, N ', N'-tetrakis (3-ethylphenyl) -1,3-phenylenediamine, N, N,
N ', N'-tetrakis (4-propylphenyl)-
1,3-phenylenediamine, N, N, N ', N'-tetraphenyl-5-methoxy-1,3-phenylenediamine, N, N-bis (3-tolyl) -N', N'-diphenyl- 1,3-phenylenediamine, N, N'-bis (4-tolyl) -N, N'-diphenyl-1,3-phenylenediamine, N, N'-bis (4-tolyl) -N,
N'-bis (3-tolyl) -1,3-phenylenediamine, N, N'-bis (4-tolyl) -N, N'-bis (3-tolyl) -3,5-tolylenediamine, N , N '
-Bis (1-ethylphenyl) -N, N'-bis (3-
Ethylphenyl) -1,3-phenylenediamine, N,
N'-bis (4-ethylphenyl) -N, N'-bis (3-ethylphenyl) -3,5-tolylenediamine,
N, N, N ', N'-tetrakis (2,4,6, -trimethylphenyl) -1,3-phenylenediamine, N,
N, N ', N'-tetrakis (2,4,6, -trimethylphenyl) -3,5-tolylenediamine, N, N,
N ', N'-tetrakis (3,5-dimethyl) -1,3
-Phenylenediamine, N, N, N ', N'-tetrakis (3,5-dimethyl) -3,5-tolylenediamine,
N, N, N ', N'-tetrakis (3,5-diethyl)
-1,3-phenylenediamine, N, N, N ', N'-
Tetrakis (3,5-dimethyl) -3,5-tolylenediamine, N, N, N ', N'-tetrakis (3-chlorophenyl) -1,3-phenylenediamine, N, N,
N ', N'-tetrakis (3-bromophenyl) -1,
3-phenylenediamine, N, N, N ', N'-tetrakis (3-iodophenyl) -1,3-phenylenediamine, N, N, N', N'-tetrakis (3-fluorophenyl) -1, 3-phenylenediamine, N, N,
N ', N'-tetrakis (2-tolyl) -1,3-phenylenediamine, N, N, N', N'-tetrakis (2
-Methoxyphenyl) -5-methyl-1,3-phenylenediamine, N, N, N ', N'-tetrakis (2-chlorophenyl) -1,3-phenylenediamine, N,
N, N ', N'-tetrakis (2-aminophenyl)-
5-methyl-1,3-phenylenediamine, N, N,
N ', N'-tetrakis (3-tolyl) -5-methyl-
1,3-phenylenediamine, N, N, N ', N'-hexakis (4-tolyl) -1,3,5-benzenetriamine, N, N, N', N'-tetrakis (3-tolyl) -5-methoxy-1,3-phenylenediamine,
N, N, N ', N'-tetrakis (3-tolyl) -1,
3,5, -Benzenetriamine, N, N, N ', N'-
Tetrakis (3-tolyl) -5-allyl-1,3-phenylenediamine, N, N, N ′, N′-tetrakis (3
-Tolyl) -5-phenyl-1,3-phenylenediamine, N, N, N ', N'-tetrakis (3-tolyl)-
5-chloro-1,3-phenylenediamine, N, N,
N ', N'-tetrakis (3-tolyl) -5-nitro-
1,3-phenylenediamine, N, N, N ′, N′-tetrakis (3-tolyl) -5-sulfo-1,3-phenylenediamine, N, N, N ′, N′-tetrakis (3-
Tolyl) -5-cyano-1,3-phenylenediamine,
N, N, N ', N'-tetrakis (3-tolyl) -5-
Formyl-1,3-phenylenediamine, N, N,
N ', N'-tetrakis (3-tolyl) -5-acetyl-1,3-phenylenediamine, N, N, N', N'-
Tetrakis (3-tolyl) -5-carboxy-1,3-
Phenylenediamine, N, N, N ', N'-tetrakis (3-tolyl) -5-ethoxycarbonyl-1,3-phenylenediamine, N, N'-bis (3-tolyl)-
N, N'-bis (2,4,6, -trimethylphenyl)
-1,3-phenylenediamine.

As the binder resin contained in the above-mentioned organic photosensitive layer, it is possible to use all those which have been conventionally used in a photoreceptor coating liquid, for example, thermosetting silicone resin, epoxy resin, urethane resin, cured resin. Acrylic resin, acrylic modified urethane resin, alkyd resin, unsaturated polyester resin, diallyl phthalate resin, phenol resin, urea resin, benzoguanamine resin, melamine resin,
Olefinic polymers such as styrene polymers, acrylic polymers, styrene-acrylic polymers, polyethylene, ethylene-vinyl acetate polymers, chlorinated polyethylene, polypropylene, ionomers; polyvinyl chloride; vinyl chloride-vinyl acetate copolymer Polyvinyl acetate; Saturated polyester; Polyamide; Thermoplastic urethane resin; Polycarbonate of bisphenol A type, bisphenol Z type, etc .; Polyarylate; Polysulfone; Ketone resin; Polyvinyl butyral resin; Polyether resin, Polyvinylcarbazole, etc. When the organic photosensitive layer is formed of a plurality of layers, the binder resin can be used to form each layer.

When the organic photosensitive layer is formed of a single layer, the thickness of the organic photosensitive layer is preferably 5 to 100 μm, more preferably 10 to 50 μm. When the organic photosensitive layer is formed of a single layer, the bisazo compound represented by the general formula (I) is added to the organic photosensitive layer in an amount of 0.
It is preferably contained in the range of 1 to 15 parts by weight, more preferably 0.5 to 10 parts by weight. When the content of the bisazo compound is less than 0.1 parts by weight, the sensitivity of the photoconductor is lowered. On the contrary, if the content of the bisazo compound is 15
If it exceeds the weight part, the abrasion resistance of the electrophotographic photosensitive member may be deteriorated.

When the organic photosensitive layer is composed of the charge generation layer and the charge transport layer, the thickness of the charge generation layer is 0.01 to 3.
μm is preferable, and 0.1 to 2 μm is more preferable. The thickness of the charge transport layer is preferably 2 to 100 μm, more preferably 5 to 50 μm.

When the organic photosensitive layer is composed of a charge generating layer and a charge transporting layer, the bisazo compound represented by the general formula (I) is 20 to 500 relative to 100 parts by weight of the binder resin of the charge generating layer. It is preferably contained in the range of parts by weight,
It is more preferably 50 to 300 parts by weight. When the content of the bisazo compound is less than 20 parts by weight, the charge generation ability is small, and conversely, the content of the bisazo compound is 500.
When it exceeds the weight part, the mechanical strength of the organic photosensitive layer may decrease.

Further, the organic photosensitive layer may contain various additives such as an antioxidant and a quencher. The conductive substrate used in the present invention is formed in an appropriate shape such as a sheet shape or a drum shape according to the mechanism and structure of the image forming apparatus in which the electrophotographic photosensitive member is incorporated. As the conductive substrate, the whole may be formed of a conductive material such as metal,
Alternatively, the base material may be formed of a material having no conductivity, and the surface thereof may be provided with a material having conductivity. The conductive material, for example, the surface is alumite-treated, or untreated aluminum, copper, tin, platinum,
Examples thereof include gold, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel, and brass. Particularly, aluminum anodized by the sulfuric acid alumite method and sealed with nickel acetate is preferably used. Be done. In the case of a conductive substrate formed by providing a conductive material on the surface of a base material made of a material having no conductivity, the surface of a synthetic resin base material or a glass base material, the above-mentioned metal or A thin film made of a conductive material such as aluminum iodide, tin oxide, indium oxide,
Those formed by a known film forming method such as a vacuum vapor deposition method and a wet plating method, a film obtained by laminating a film of the metal material or the like on the surface of the base material, and a substance which imparts conductivity to the surface of the base material. It is possible to use an injected material or the like. The conductive base material may be subjected to a surface treatment with a surface treatment agent such as a silane coupling agent or a titanium coupling agent, if necessary, to enhance the adhesiveness with the organic photosensitive layer.

The electrophotographic photoreceptor of the present invention is spray-coated with a coating solution prepared by dispersing at least a binder resin and the bisazo compound represented by the general formula (I) in tetrahydrofuran or the like as a solvent or a dispersion medium. Method, dipping method, flow coating method or the like to form an organic photosensitive layer by coating on a conductive substrate. It is preferable to perform heat treatment in order to reduce the amount of tetrahydrofuran remaining in the organic photosensitive layer. For example, it is preferable to heat-treat the conductive substrate coated with the coating liquid at a temperature of 120 ° C. or higher for 30 minutes or longer. .. When the heat treatment temperature is lower than the above conditions, the residual amount of tetrahydrofuran may not be sufficiently reduced.

As the solvent or dispersion medium used in the coating liquid, other solvent or dispersion medium may be used alone or in combination with tetrahydrofuran in addition to tetrahydrofuran.

Examples of such a solvent or dispersion medium include the following. Aliphatic hydrocarbons such as n-hexane, octane and cyclohexane; aromatic hydrocarbons such as benzene, xylene and toluene; halogenated hydrocarbons such as dichloromethane, carbon tetrachloride, chlorobenzene and methylene chloride; methyl alcohol, ethyl alcohol, isopropyl Alcohols such as alcohol, allyl alcohol, cyclopentanol, benzyl alcohol, furfuryl alcohol, diacetone alcohol; ethers such as dimethyl ether, diethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether; acetone, methyl ethyl ketone, methyl isobutyl ketone, Ketones such as cyclohexanone; esters such as ethyl acetate and methyl acetate; dimethylformamide; dimethylsulfoxide and the like.

The coating liquid is a conventionally known method, for example, a mixer, a ball mill, a paint shaker, a sand mill,
It can be prepared using an attritor, an ultrasonic disperser or the like. When preparing the above coating liquid, a surfactant, a leveling agent or the like may be added in order to improve dispersibility, coatability and the like.

[0044]

The present invention will be described in detail below with reference to examples. As Examples 1 to 8 the charge generating material, the azo compound represented by the general formula (Ia) (and A is a coupler residue, introduction position and the type of R ¹ are specifically described in Table 1) a Using the following procedures, single-layer type and laminated type photoreceptors were prepared.

Preparation of Single Layer Type Electrophotographic Photoreceptor 8 parts by weight of an azo compound as a charge generating material and 3,3'-dimethyl-N, N, N ', N' as a charge transporting material.
-Tetrakis-4-methylphenyl- (1,1'-bisphenyl) -4,4'-diamine 100 parts by weight and 100 parts by weight of polyester as a binder resin were added to a predetermined amount of tetrahydrofuran and mixed and dispersed by a ball mill. A single layer type photosensitive layer coating solution was prepared. This coating solution was applied onto an aluminum tube and then dried at 100 ° C. for 30 minutes in the dark to prepare a single-layer type electrophotographic photoreceptor having a photosensitive layer with a thickness of 24 μm.

Preparation of Laminated Electrophotographic Photoreceptor As a binder resin, 100 parts by weight of polyvinyl butyral,
Charge 100 parts by weight of an azo compound and a predetermined amount of tetrahydrofuran as a charge generation material into a ball mill,
A charge generation layer coating solution is prepared by stirring and mixing for a period of time, and the prepared solution is coated on an aluminum tube by a dipping method,
A charge generation layer having a film thickness of 0.5 μm was formed by drying in hot air at 10 ° C. for 30 minutes and curing.

Next, 100 parts by weight of a polycarbonate resin as a binder resin and 3,3'- as a charge transport material.
Dimethyl-N, N, N ', N'-tetrakis-4-methylphenyl- (1,1'-bisphenyl) -4,4'-
100 parts by weight of diamine and a predetermined amount of toluene are mixed by stirring with a homomixer to prepare a charge transport layer coating solution, and the prepared solution is coated on the above charge generating layer by a dipping method and heated with hot air at 90 ° C. for 30 minutes. Film thickness 20 by drying
A charge transport layer having a thickness of μm was formed to prepare an electrophotographic photoreceptor.

Comparative Examples 1 to 5 In the same manner as in Example 1 except that a bisazo compound represented by the following general formula (V) was used as the charge generating material, single-layer type and multi-layer type photosensitive materials were used. Created the body. Specific examples of the coupler residue B include the following E
The groups represented by 1 to E5 are listed, and the groups used are shown in Table 2.

[0049]

[Chemical 9]

(In the formula, B represents a coupler residue.)

[0051]

[Chemical 10]

Comparative Examples 6 to 8 Single layer type and laminated type photosensitive materials were prepared in the same manner as in Example 1 except that an azo compound represented by the following general formula (Ib) was used as the charge generating material. Created the body. Specific examples of the coupler residue C include the following E
The groups represented by 3, E5 and E6 are mentioned, and the groups used are shown in Table 2.

[0053]

[Chemical 11]

(In the formula, C represents a coupler residue.)

[0055]

[Chemical 12]

The following tests were carried out on the electrophotographic photosensitive members of the above-mentioned respective Examples and Comparative Examples to evaluate their characteristics. 1) Measurement of initial surface potential Vsp Each electrophotographic photosensitive member is charged in an electrostatic copying tester (Gentec Cynthia 30M, manufactured by Gentech Co., Ltd.), and the surface is charged positively or negatively, and the surface of each photoconductor is charged. Potential Vsp
(V) was measured. 2) Measurement of half-exposure amount E1 / 2 and residual potential Vrp Each of the electrophotographic photoconductors in the above charged state was exposed at an exposure intensity of 10 lux using a halogen lamp which is an exposure light source of the above electrostatic copying test apparatus, and the surface was exposed. The time until the potential Vsp becomes 1/2 is obtained, and the half-exposure amount E1 / 2 (lux · se
c) was calculated. Further, the surface step after 0.5 seconds has elapsed from the start of the exposure is defined as the residual potential Vrp (V). 3) Repeatability Δsp Each electrophotographic photosensitive member is a copying machine (DC-111 Mita Kogyo)
Vsp after repeated use 500 times,
The amount of change was calculated. However, the surface potential is measured by a surface electrometer (M
It was measured using MODEL224 manufactured by ONROE.

The above results are shown in Tables 1 and 2.

[0058]

[Table 1]

[0059]

[Table 2]

From Tables 1 and 2, the charge generation materials of Examples are as follows:
It can be seen that the charge generation efficiency is excellent, and the single-layer type and multi-layer type electrophotographic photoconductors have high sensitivity and excellent repeating characteristics.

[0061]

As is clear from the above description, according to the electrophotographic photoreceptor of the present invention, it is possible to provide an electrophotographic photoreceptor having high sensitivity in the visible light region and excellent in repeating characteristics. ..

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasushi Mizuta 1-2-2 Tamazo, Chuo-ku, Osaka-shi, Osaka Within Mita Kogyo Co., Ltd. (72) Inventor Ikuhiko Kawahara 1-2-chome, Chuzo-ku, Osaka-shi, Osaka No. 28 Mita Industry Co., Ltd.

Claims (1)

[Claims] 1. A photoreceptor comprising a photosensitive layer containing an azo compound represented by the following general formula (I) on a conductive substrate. [Chemical 1] (In the formula, m and n each independently represent 1 or 2, R ¹ represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, an amino group, a cyano group, a nitro group, a sulfoxide group, A represents a coupler residue having no donor property.)