JPH0823703B2 - Electrophotographic photoreceptor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to an electrophotographic photoreceptor, and more particularly to a novel electrophotographic photoreceptor having a photosensitive layer containing an azo pigment.

More specifically, it relates to a highly durable electrophotographic photosensitive member which has high sensitivity and is suitable for repeated use.

(B) Conventional Technology and its Problems Conventionally, as electrophotographic photoreceptors, selenium, zinc oxide,
Those having a photosensitive layer containing an inorganic photoconductor such as cadmium sulfide as a main component have been widely known.

However, these are not always satisfactory in sensitivity, thermal stability, moisture resistance, durability, etc., and in particular,
Selenium and cadmium sulfide are toxic and therefore
There were also restrictions on handling.

On the other hand, an electrophotographic photoreceptor having a photosensitive layer containing an organic photoconductive compound as a main component is relatively easy to manufacture.
Further, it generally has many advantages as compared with selenium photoconductors, such as being superior in thermal stability, and has received much attention in recent years.

As such an organic photoconductive compound, poly-N
-Vinylcarbazole is well known and this and 2,4,
An electrophotographic photoreceptor having a photosensitive layer containing a charge transfer complex formed from a Lewis acid such as 7-trinitro-9-fluorenone as a main component is not always satisfactory in sensitivity and durability.

On the other hand, layered or dispersed function-separated type photoconductors in which carrier generation function and carrier movement function are shared by separate substances, have wide selection range of each material, charging property, sensitivity and durability. It has an advantage that an electrophotographic photosensitive member having arbitrary electrophotographic characteristics can be prepared relatively easily.

Conventionally, various substances have been proposed as carrier-generating substances or carrier-moving substances.

For example, an electrophotographic photoreceptor having a photosensitive layer in which a carrier generating layer made of amorphous selenium and a carrier moving layer containing poly-N-vinylcarbazole as a main component are combined has been put into practical use.

However, the carrier generating layer made of amorphous selenium has a drawback that it has poor durability.

Further, various proposals have been made to use organic dyes and organic pigments as carrier generating substances. For example, as an electrophotographic photoreceptor containing a monoazo pigment or a bisazo pigment in a photosensitive layer, Japanese Patent Publication No. 48-30513, JP-A-52-4241, JP-A-54-46558 and JP-B-56-11945 are already known.

However, these azo pigments are not always satisfactory in characteristics such as sensitivity, residual potential or stability when repeatedly used, and the selection range of carrier transfer substances is also limited. The reality is that nothing that satisfies a wide range of requirements has yet to be obtained.

(C) Object of the Invention An object of the present invention is to provide an electrophotographic photoreceptor containing an azo pigment which is stable to heat and light and has an excellent carrier-generating ability.

Another object of the present invention is to provide an electrophotographic photosensitive member which has high sensitivity and a small residual potential, and whose durability does not change even after repeated use, and which has excellent durability.

Still another object of the present invention is to provide an electrophotographic photoreceptor containing an azo pigment which can effectively act as a carrier generating substance even in combination with a wide range of carrier transferring substances.

(D) Structure of the Invention The inventors of the present invention have found that the azo pigment represented by the following general formula [I] can act as an active ingredient of a photoconductor as a result of earnest research to achieve the above object. Is completed.

(In the formula, A and B each represent a phenyl group which may have a substituent, a naphthyl group, a heterocyclic group or an alkyl group,
Cp represents a coupler residue. ) Cp represents a residue of a coupler that reacts with a diazo group, and a coupler residue having a structure represented by the following general formula [II] is particularly effective.

(Where Y is condensed with a benzene ring to form a polycyclic aromatic ring such as naphthalene or anthracene ring, or condensed with a benzene ring to form a heterocyclic ring such as a carbazole ring, a benzocarbazole ring or a dibenzyldifuran ring. R ₁ is an optionally substituted alkyl group (eg, methyl group, ethyl group, n-propyl group, iso-propyl group,
n-butyl group, sec-butyl group, amyl group, 1-octyl group, benzyl group, p-chlorobenzyl group, 3,4 dichlorobenzyl group, p-methylbenzyl group, 2-phenylethyl group, α-naphthyl group Methyl group, β-naphthylmethyl group) Aryl group (for example, phenyl group, ethylphenyl group, tolyl group, xylyl group, biphenyl group, chlorophenyl group, dichlorophenyl group, bromophenyl group, methoxyphenyl group, ethoxyphenyl group, butoxyphenyl group) , Phenoxyphenyl group, nitrophenyl group, cyanophenyl group, hydroxyphenyl group, carboxyphenyl group, N, N-dimethylaminophenyl group, α, α, α
-Trifluoromethylphenyl group, methylthiophenyl group, α-naphthyl group, β-naphthyl group, etc.), R ₂ is R ₁ and a heterocyclic group, (for example, thiazolyl group, 5-nitrothiazolyl group, carbazolyl group, indolyl group, pyrrolyl Group, acridyl group, benzo (b) thiophenyl, benzoinmidazolyl group, oxazolyl group, chlorooxazolyl group,
A triazolyl group, a piperidyl group, a pyridyl group, a kyrinor group and the like).

R ₃ represents O, S, and -NH-, R _4, R ₅ represents hydrogen, an optionally substituted alkyl group, a nitro group, a methoxy group, an ethoxy group, an acetyl group, a cyano group, a halogen.

Z is a chain hydrocarbon necessary for forming a 5-membered ring or a 6-membered ring. That is, in the present invention, by using the azo pigment represented by the general formula [I] as a photoconductive substance constituting the photosensitive layer of an electrophotographic photoreceptor, an excellent carrier for the azo pigment of the present invention can be obtained. Utilizing only the generating ability, and by using this as a carrier generating substance of a so-called function-separated electrophotographic photoreceptor in which carrier generation and migration are performed by separate substances, excellent film physical properties, charge retention, sensitivity, An electrophotographic photosensitive material that has excellent electrophotographic characteristics such as residual potential, has little fatigue deterioration even after repeated use, and does not change the above characteristics due to heat or light, and can exhibit stable characteristics. You can create a body.

Specific examples of the azo pigment represented by the general formula [I] useful in the present invention include those having the following structural formulas:
However, the azo pigment of the present invention is not limited thereto.

Exemplified azo pigment The azo pigment represented by the general formula [I] has the general formula The divalent amino compound represented by the formula (1) is azotized by a conventional method, and then the corresponding coupler is coupled in the presence of an alkali, or the above-mentioned diazonium salt of the divalent amino compound is fluorinated or zinc chloride double salt. Etc., once isolated, and then subjected to a coupling reaction with a coupler in the presence of an organic or inorganic alkali in a suitable solvent (for example, N, N-dimethylformamide, dimethylsulfoxide, ethanol, dioxane). Therefore, it can be easily synthesized.

Next, a synthesis method of a typical example of the azo pigment used in the present invention will be shown.

Synthesis Example (Exemplified Azo Pigment No. 1) (1-1) Acetophenone-phenylhydrazone is obtained by reacting equimolar amounts of acetonephenone and phenylhydrazine in ethanol in the presence of a slight amount of glacial acetic acid. The hydrazone thus obtained is used with phosphorus oxychloride and dimethylformamide to obtain a pyrazole compound represented by the following structural formula.

(Resolving solvent: ethanol) (Melting point 149.5 to 151.0 ° C.) (1-2) Pyrazole aldehyde thus obtained and 2,7-dinitroflorene are added to n-butyl alcohol with a small amount of piperidine and heated under reflux.
The crystallized product which turned orange when hot was collected by filtration, thoroughly washed with methanol and heat washed with acetone to obtain a dinitro compound represented by the following structural formula almost quantitatively.

(Melting point 315.5-317.0 ° C) (1-3) The dinitro compound thus obtained is reduced with glacial acetic acid and reduced iron to give the diamino compound of the above structural formula (melting point).
284.5 ℃ ~ 286.0 ℃) is obtained.

(Resolving solvent: isopropyl alcohol) The IR diagram (KBr tablet method) of this diamino compound is shown in Fig. 1.

(1-4) A solution prepared by dissolving 0.32 g of sodium nitrite in a minimum amount of water in a slurry solution of 0.94 g of the diamino compound and 10 cc of 1N hydrochloric acid was ice-cooled and reacted for about 2 hours.

Then activated carbon was added and filtered to prepare a diazonium salt solution.

As a coupling component, 1.4 g of 2-hydroxy-3-naphthoic acid anilide was dissolved in 50 ml of dimethylformamide, and then a solution of 1.7 g of sodium acetate in a minimum amount of water was added and the mixture was cooled to 5 to 10 ° C.

Next, the above-mentioned diazonium salt was dropped into the coupler solution, the blackish blue paste liquid thus formed was returned to room temperature, and further stirred for 3 hours. The formed precipitate was filtered, thoroughly washed with dimethylformamide, washed with hot water, finally washed with acetone, and dried under reduced pressure at 80 ° C. to obtain 1.9 g of a black powder having a slightly metallic luster.

mp = 343 ° C. (dec) Synthesis Example 2 (Exemplified Azo Pigment No. 2) The diamino compound obtained in Synthesis Example 1 was similarly converted to a diazonium salt, and 2-hydroxy-3 was used as a coupling component.
-Naphthoic acid- (p-chloroanilide) (melting point 274-276
(° C) was used for the synthesis.

 This pigment was also a black powder having a metallic luster.

mp = 350 ° C. or higher Synthesis Example 3 (Exemplified Azo Pigment No. 4) Synthesis Example 1 except that 2-hydroxy-3-naphthoic acid- (p-cyanoanilide) (melting point 278 to 283.5 ° C.) was used as a coupling component. Synthesis was performed in exactly the same manner.

 This pigment was also a black powder having a slight metallic luster.

mp = 350 ° C. or more Synthesis Example 4 (Exemplified Azo Pigment No. 6) (2-1) p-Chloroacetophenone Get phenylhydrazone. The hydrazone thus obtained is used with phosphorus oxychloride and dimethylformamide to obtain a pyrazole compound represented by the following structural formula. (Resolving solvent: ethanol) (Melting point 146.5-148.0 ° C.) (2-2) The aldehyde derivative of pyrazole thus obtained and 2,7-dinitroflorene are added to n-amyl alcohol with a small amount of piperidine and heated under reflux. The precipitated reddish brown dough crystals were taken out and sufficiently washed with acetone to obtain a dinitro compound represented by the following structural formula almost quantitatively.

(Melting point 316.5 to 318 ° C) (2-3) The dinitro compound thus obtained is reduced with hydrochloric acid and tin to give the diamino compound of the above structural formula (melting point).
251 ℃ ~ 253 ℃) is obtained.

(Resolving solvent: ethanol) An IR diagram (KBr tablet method) of this diamino compound is shown in Fig. 2.

(2-4) A solution prepared by dissolving sodium nitrite 0.35 in a minimum amount of water in a slurry solution of 0.92 g of the above diamino compound and 10 cc of 1N hydrochloric acid was ice-cooled and reacted for about 2 hours. After removing the insoluble matter, about 2.0 g of borofluoric acid was added to the solution, and the reddish brown crystals precipitated were taken out, washed thoroughly with water, and dissolved in DMF to form a diazonium salt.

Next, activated carbon was added and filtered to prepare a diazonium salt solution.

2-Hydroxy-3-naphthoic acid- (p-trifluoromethylanilide) as a coupling component (melting point 287.5
~ 290 ° C) 1.6g dissolved in 50ml DMF, then 1.2g pyridine
Was added to cool the coupler solution to 5-10 ° C.

Then, a diazonium salt solution was added dropwise to this solution in a short time, the resulting blackish blue paste-like solution was returned to room temperature, and the mixture was further stirred for 3 hours.

The deposited bisazo pigment was purified in the same manner as in Synthesis Example 1 to obtain 1.7 g of a black powder having a metallic luster.

mp = 350 ° C. or higher Other azo pigments of the present invention can also be obtained according to the above synthesis examples.

The electrophotographic photoreceptor of the present invention has a photosensitive layer containing one kind or two or more kinds of the azo pigments represented by the general formula [I]. Although various types of photosensitive layers are known, the photosensitive layer of the electrophotographic photoreceptor of the present invention may be any of them. Usually, it is a photosensitive layer of the type illustrated below.

Photosensitive layer composed of azo pigment Photosensitive layer in which azo pigment is dispersed in binder Photosensitive layer in which azo pigment is dispersed in well-known charge transfer material The above-mentioned photosensitive layers are charge generation layers, and well-known charge transfer material A photosensitive layer in which a charge transfer layer containing is laminated. When the azo pigment represented by the general formula absorbs light, it generates a charge carrier with extremely high efficiency. The generated carrier can move using an azo pigment as a medium, but it is preferable to move a known charge transfer substance as a medium. From this point, the photosensitive layer of the form and is particularly preferable.

Charge transfer substances are generally classified into two types, electron transfer substances and hole transfer substances. Both can be used in the photosensitive layer of the photoreceptor of the present invention, and a mixture of those having the same type of function or Mixtures of those having different functions can also be used. The substance having electron transfer is an electron-withdrawing compound having an electron-withdrawing group such as a nitro group, a cyano group and an ester group, and as these substances, for example, 2,4,
Nitrated fluorenones such as 7-trinitrofluorenone, 2,4,5,7-tetranitrofluorenone, or tetracyanoquinodimethane, tetracyanoethylene, 2,4,5,7
Examples thereof include compounds such as tetranitroxanthone and 2,4,8-trinitrothioxanthone, and compounds obtained by polymerizing these electron absorbing compounds.

Further, as the hole transfer medium, examples of electron donating organic photoconductive compounds include the following.

Aromatic amine compounds Hydrazone compounds Heterocyclic compound And so on. Other polymer compounds include poly-N-vinylcarbazole and halogenated poly-
N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinylacridine, polyglycidylcarbazole, polyvinylacenaphthylene, ethylcarbazoleformaldehyde resin, and the like can also be used.

The carrier transfer substance is not limited to those described here, and when used, one or two or more carrier transfer substances may be mixed and used.

The electrophotographic photoreceptor of the present invention can be manufactured by a conventional method.

For example, for an electrophotographic photoreceptor having a photosensitive layer of the type described above, a coating solution obtained by dissolving or dispersing the azo pigment represented by the general formula [I] in a suitable medium is coated on a conductive support. , Dried, usually several dozen μm to several dozen μm
It can be manufactured by forming a photosensitive layer having a film thickness of.

As a medium for preparing the coating solution, a basic solvent that dissolves an azo pigment such as n-butylamine or ethylenediamine, or an ether such as tetrahydrofuran or 1,4-dioxane: methyl ethyl ketone, a ketone such as cyclohexanone: toluene, xylene, etc. Aromatic hydrocarbons: N, N−
Aprotic polar solvents such as dimethylformamide, acetonitrile, N-methylpyrrolidone and dimethylsulfoxide: alcohols such as methanol, ethanol and isopropanol: esters such as ethyl acetate, methyl acetate, methyl cellosolve acetate: chlorine such as dichloroethane and chloroform A medium in which an azo pigment such as a modified hydrocarbon is dispersed may be used.

When a medium in which the azo pigment is dispersed is used, it is necessary to make the azo pigment into fine particles having a particle size of 5 μm or less, preferably 3 μm or less, and most preferably 1 μm or less.

Further, as the conductive support on which the photosensitive layer is formed, any of those known in electrophotographic photoreceptors can be used.

Specific examples thereof include metal drums such as aluminum and copper, sheets, laminates of these metal foils, and vapor-deposited materials.

Further, there may be mentioned plastic films, plastic drums, papers, etc. which have been subjected to a conductive treatment by coating a conductive substance such as metal powder, carbon black, copper iodide, or a polymer electrolyte with a suitable binder.

In addition, examples include conductive plastic sheets and drums containing conductive materials such as metal powder, carbon black, and carbon fibers.

By dissolving the binder in the coating liquid used for forming the photosensitive layer of the above type, an electrophotographic photoreceptor having the photosensitive layer of the above type can be produced.

In this case, the medium of the coating liquid preferably dissolves the binder.

As the binder, styrene, vinyl acetate, acrylic acid, polymers and copolymers of vinyl compounds such as methacrylic acid, phenoxy resin, polysulfone, polyarylate, polycarbonate, polyester, cellulose ester, cellulose ether, butyral resin, epoxy Examples include various polymers such as resins and acrylic polyol resins.

The amount of binder used is usually 0.1 to 5 relative to the azo pigment.
It is in the range of weight times.

When forming a photosensitive layer of this type, an azo pigment is used in a binder, for example, with a particle size of 3 μm.
It is preferable that the particles are present in the form of fine particles of m or less, especially 1 μm or less.

Similarly, if the charge transfer medium is dissolved in the coating liquid used for forming the photosensitive layer of the above type, the electrophotographic photoreceptor having the photosensitive layer of the above type can be manufactured.

As the charge transfer medium, any of those exemplified above can be used.

Aside from the charge transfer medium such as polyvinyl carbazole and polyglycidyl carbazole which can be used as a binder itself, it is preferable to use a binder for other substances.

As the binder, any of those exemplified above can be used.

In this case, the amount of binder used is usually
It is in the range of 0.5 to 100 times by weight, and the amount of the charge medium used is usually 0.2 to 3.0 times by weight, preferably
It is in the range of 0.3 to 1.2 times the weight. In the case of a charge transfer medium which itself can be used as a binder, it is usually used in an amount of 1 to 10 times by weight with respect to the azo pigment.

This type of photosensitive layer is the same as the type of photosensitive layer described above.
It is preferable that the azo pigment is present in the charge transfer medium and the binder in the form of fine particles.

An electrophotographic photosensitive material having a photosensitive layer of any of the above types can be formed by applying a coating solution obtained by dissolving a charge transfer medium in an appropriate medium onto the photosensitive layers of the above types (1) to (4) to form a charge transfer layer. The body can be manufactured.

In this case, the photosensitive layers of the above types 1 to 4 serve as a charge generation layer. The charge transfer layer does not necessarily have to be provided on the charge generation layer, and may be provided between the charge generation layer and the conductive support.

 However, the former is preferable in terms of durability.

The charge transfer layer is formed in the same manner as the above-mentioned photosensitive layer. That is, a coating solution obtained by removing the azo pigment from the coating solution for forming the photosensitive layer may be used as the coating solution.

 The charge transfer layer is usually 5 to 50 μm thick.

Of course, the photosensitive layer of the electrophotographic photoreceptor of the present invention may contain a known sensitizer.

Suitable sensitizers include Lewis acids and dye dyes that form charge transfer complexes with organic photoconductive materials.

Examples of the Lewis acid include chloranil, 2,3-dichloro-1,4-naphthoquinone, 2-methylanthraquinone,
1-nitroanthraquinone, 1-chloro-5-nitroanthraquinone, 2-chloroanthraquinone, quinones such as phenatrenequinone, aldehydes such as 4-nitrobenzaldehyde, 9-benzoylanthracene, indandione, 3,5-dinitro Benzophenone, 3,3 ′,
Ketones such as 5,5-tetranitrobenzophenone, phthalic anhydride, acid anhydrides such as 4-chloronaphthalic anhydride,
Tetracyanoethylene, terephthalmalondinitr,
Cyano compounds such as 4-nitrobenzalmalon nitrile: 3
Examples thereof include electron-withdrawing compounds such as benzalphthalide, 3- (α-cyano-p-nitrobenzal) phthalide, and 3- (α-cyano-p-chlorobenzal) phthalide.

Examples of the dyes include triphenylmethane dyes such as methyl violet, brilliant green and crystal violet, thiazine dyes such as methylene blue, quinone dyes such as quinizarine, cyanine dyes, pyrylium salts, thiapyrylium salts and benzopyrylium salts.

In addition to these, inorganic photoconductive fine particles such as selenium and selenium-arsenic alloy, and organic photoconductive pigments such as copper-phthalocyanine pigment and perylene pigment may be contained.

Further, the photosensitive layer of the electrophotographic photoreceptor of the present invention may contain a well-known plasticizer in order to improve film-forming property, flexibility and mechanical strength. Examples of the plasticizer include organic compounds such as phthalic acid ester, phosphoric acid ester, epoxy compound, chlorinated paraffin, chlorinated fatty acid ester, and alkylated naphthalene.

Needless to say, it may have an adhesive layer, an intermediate layer, and a photoreceptor protective layer, if necessary.

A photoreceptor using the azo pigment of the present invention has a high sensitivity and a good color sensitivity, and when repeatedly used, the sensitivity and the chargeability do not fluctuate, the light fatigue is small, and the durability is extremely excellent. Is.

Further, the photoconductor of the present invention can be widely used in electrophotographic application fields such as a photoconductor of a printer using a laser, a cathode ray tube (CRT), and a light emitting diode (LED) as a light source, in addition to an electrophotographic copying machine.

(E) Examples Next, the present invention will be described more specifically with reference to Examples.
The present invention is not limited to the following examples unless it exceeds the gist.

Example 1 Polyester film laminated with aluminum foil (Albet 85 made by Daido Kako, aluminum film thickness 10μ)
It is obtained by adding 2 g of Exemplified Azo Pigment No. 2 and 1 g of butyral resin (Eslex B manufactured by Sekisui Chemical Co., Ltd.) to 100 ml of tetrahydrofuran and dispersing in a bain conditioner for about 1 hour on a conductive support consisting of The azo pigment dispersion is applied and dried so that the film thickness after drying is 0.3 μm to form a carrier generating layer.
N-diphenylaminobenzaldehyde-1,1-diphenylhydrazone 5 g together with polyarylate resin 7 g 1,2-
The film thickness after drying the solution dissolved in 50 ml of dichloroethane was 19
The carrier moving layer was formed by coating and drying so as to have a thickness of μ, and the electrophotographic photosensitive member of the present invention was produced. After this photoconductor was stored at room temperature in the dark at 30 ° C for one week, the electrophotographic photoconductor was attached to an electrostatic paper testing device "SP-428" (manufactured by Kawaguchi Denki Seisakusho) and the following characteristic tests were conducted. .

That is, a voltage of 6 KV was applied to the photosensitive layer to charge the photosensitive layer by corona discharge for 5 seconds, and the potential at that time was Vo (-V),
Then, the surface potential of the photosensitive layer is reduced to 1 / by irradiating light from a halogen lamp with the illuminance on the surface of the photosensitive layer being 30 lux.
The exposure dose E1 / 2 (lux · sec) required to attenuate to 2 was obtained.

The surface potential after exposure with an exposure amount of ₁₀ lux · sec, that is, the residual potential E ₁₀ (−V) was determined. Similar measurements
Repeated 500 times. The residual potential was completely reduced to 0 by further performing irradiation exposure with 300 lux for 0.3 seconds using a tungsten lamp as a light source for slowly discharging the residual potential.

 The results are shown in Table 1.

Examples 2 to 10 As the carrier generating substance, exemplified azo pigments No. 3 and No. 3, respectively.
No.5, No.6, No.13, No.22, No.27, No.34, No.37, No.
A total of 9 kinds of electrophotographic photosensitive members of the present invention were prepared in the same manner as in Example 1 except that Nos. 44 and 44 were used, and the same characteristic test was conducted for each of them. The results are shown in Table 2.

Example 11 Obtained by adding 2 g of Exemplified Azo Pigment No. 8 to 100 ml of tetrahydrofuran in which 2 g of polyarylate resin was dissolved and dispersing for about 3 hours using a bain conditioner on the outer surface of a drum made of aluminum and having a diameter of 60 mm. To the resulting dispersion, 100 ml of tetrahydrofuran was further added, and the resulting solution was applied and dried so that the film thickness after drying was 0.5 μm to form a carrier generation layer. Structural formula on this carrier generation layer 20 g of a carrier transfer substance N, N-diethylaminobenzaldehyde-1- (phenyl) -1-methylhydrazone represented by
-1250) and a solution of 20 g dissolved in 150 ml of 1,2-dichloroethane to form a carrier moving layer by coating and drying so as to have a film thickness of 15 μ after drying, and a drum type electrophotographic photoreceptor according to the present invention is produced. did.

When this electrophotographic photosensitive member was mounted on our commercial modified electronic copying machine for office use to form a copied image, a high-contrast and clear visible image faithful to the original was obtained.

Further, copying was repeated 1000 times continuously, but a visible image equivalent to that of the first time was obtained until the end.

Example 12 The reflection spectrum of the drum-type electrophotographic photosensitive member obtained in Example 11 was measured by a spectrophotometer (UV-365 manufactured by Shimadzu) equipped with an integrating sphere, and the maximum absorption wavelength in the visible part of the photosensitive member was measured. Is 66
It was found to be in the vicinity of 0 nm to 690 nm and 600 nm to 630 nm.

Further, the spectral sensitivity of this photoconductor between 500 nm and 750 nm was measured using a monochromator, and the results are shown in FIG. The spectral sensitivity was required to attenuate the potential from -600V to -300V. It was expressed in energy (μJ / cm ² ).

It has been found that the photoconductor can withstand practical sensitivity even if a light emitting diode or a He-Ne laser is used as a light source.

Example 13 Styrene: n-butyl methacrylate: methacrylic acid copolymer (styrene: n-butyl methacrylate = 1: 2 weight ratio, acid value 250) and exemplified azo pigment No. on a grainy surface-oxidized Al plate. 6- and 2-phenyl-1-ethylindole-3
-Aldehyde 1,1-diphenylhydrazone at 1.5: 0.2: 1.1
In a dioxane and dissolved (resin component, hydrazone compound) dispersed (azo pigment) in a dioxane solution and dried. An electrophotographic characteristic test was conducted.

Applied voltage + 6V Vo = 520Volt E1 / 2 = 3.9lux ・ sec.

Further, the present photoreceptor is visualized with a developer (toner) and then an alkaline treatment aqueous solution (eg, 3% triethanolamine, 10% sodium acetate, 15% polyethylene glycol having an average molecular weight of 190 to 210, 5% benzyl alcohol). The non-toner-attached portion was easily eluted by the treatment (1) and then washed with water containing sodium silicate, whereby a printing original plate could be easily prepared.

It was found that offset printing using this original plate can withstand printing of approximately 100,000 sheets.

The optimum exposure amount for obtaining a toner visible image (light source: halogen lamp) was 100 lux · sec, and when a printing original plate was prepared, direct plate-making was carried out without using a master plate material.

[Brief description of drawings]

FIG. 1 is an IR diagram of the diamino bases of Exemplified Azo Pigments No. 1, No. 2, No. 3, and No. 4, and FIG.
5, No. 6, No. 7, No. 8 diamino base IR diagram,
FIG. 3 is a spectral sensitivity curve of the photoconductor of the present invention in Example 11.

Continuation of the front page (56) Reference JP-A-60-168155 (JP, A) JP-A-60-196769 (JP, A) JP-A-60-216355 (JP, A) JP-A-61-107356 (JP , A) JP 61-109780 (JP, A) JP 62-286058 (JP, A) JP 63-44663 (JP, A)

Claims (3)

[Claims] 1. An electrophotographic photosensitive member comprising a conductive support and a photosensitive layer containing an azo pigment represented by the following general formula [I]. (In the formula, A and B each represent an aryl group, a heterocyclic group, or an alkyl group which may have a substituent, and Cp represents a coupler residue.) 2. The photosensitive layer contains a carrier transfer substance and a carrier generating substance, and the carrier generating substance is an azo pigment represented by the general formula [I]. Electrophotographic photoreceptor. 3. The azo pigment represented by the general formula [I] is
Claim 1 which is a compound represented by the following general formula
Item. (In the formula, A, B, and Cp have the same meaning as in the first term.)