JPS62100760A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body having high stability to heat and light and superior capability for generating carrier by using a specified azo pigment for a photoconductive substance for constituting a photosensitive layer of the electrophotographic sensitive body. CONSTITUTION:An electrophotographic sensitive body is provided with a photosensitive layer contg. an azo pigment expressed by the formula on an electroconductive base body. The azo pigment generates charge carrier with high efficiency when the pigment absorbs light within a range from visible light having 500nm-850nm wavelength to near infrared rays. Generated carrier can be transferred utilizing the azo pigment itself as medium, but it is more preferable that the carrier is transferred using conventional charge transfer substance as medium.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention 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, the present invention relates to a highly durable single-child photographic photoreceptor which has high sensitivity and is suitable for single-return use and has sensitivity up to the near-infrared region.

(B) Prior Art and its Problems Conventionally, as electrophotographic photoreceptors, those having a photosensitive layer containing an inorganic photoreceptor such as selenium, zinc chloride, or cadmium sulfide as a main component have been widely known.

However, these are not necessarily satisfactory in terms of sensitivity, thermal stability, mold resistance, durability, etc. In particular, selenium and (cadmium effluent) are
There were also restrictions on how castles could be treated.

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. In addition, they generally have many advantages over selenium photoreceptors, such as superior thermal stability, and have attracted much attention in recent years. ' As such organic photo-4'ljt compounds, BoI
J-N-vinylcarbazole is well known, and electrophotography has a photosensitive layer containing a charge transfer complex formed from J-N-vinylcarbazole and a Lewis acid such as 2.4.7-)Lielow-9-fluorenone. Photoreceptors are not always satisfactory in sensitivity and durability.

On the other hand, a laminated type or distributed type functional component 1ida! in which carrier generation prevention ability and carrier transfer ability are assigned to separate substances, respectively. ! The photoreceptor has the advantage that each material can be selected from a wide range, and an electrophotographic photoreceptor having arbitrary electrophotographic properties such as band 1Jt characteristics, lability, and durability can be produced relatively easily. .

Hitherto, Umeume substances have been proposed as carrier-generating substances or carrier-transferring substances.

For example, an electrophotographic photoreceptor having a photosensitive layer combining a carrier generation layer made of amorphous selenium and a carrier transfer layer mainly composed of poly-N-vinylcarbazole is commercially available.

However, a carrier generation layer made of amorphous selenium has a drawback of poor durability.

In addition, various proposals have been made to use organic dyes and pigments as carrier-generating substances.
Japanese Patent Publication No. 48-30513, Japanese Patent Publication No. 52-4241
Publication No. 1983-46558, Japanese Patent Publication No. 1987-46558
11945 and the like are already known.

However, these azo pigments have low sensitivity, residual potential or #! 1-1 of the electrophotographic process is not always satisfactory in terms of characteristics such as stability when used repeatedly, and the selection range of carrier #animal material is also limited.
The reality is that nothing that fully satisfies a wide range of demands has yet been obtained.

(Q. Purpose of the Invention The purpose of the present invention is to provide an electrophotographic photoreceptor containing an azo preparation that is stable against heat and light and has a low carrier generation ability.

Another object of the present invention is to provide high sensitivity, low residual '1', and no change in characteristics even when MD is used again.
An object of the present invention is to provide an electrophotographic photoreceptor with excellent durability.

Another object of the present invention is to provide an electrophotographic photoreceptor containing an azo pigment that can effectively act as a carrier generating substance even in combination with a wide variety of carrier transfer substances.

υ) Constitution of the Invention As a result of intensive research to achieve the above object, the present inventors discovered that an azo IgI material represented by the following general formula (Il) can function as an active ingredient of a photoreceptor, and the present invention This is the completed version.

(In the formula, R is hydrogen, a lower alkyl group, a phenyl group that may contain an M-alternative group, or a styryl group; n is 0 or 1, and Cp represents a Kagura residue.) Cp represents a bridge group of a coupler that reacts with a diazo group;
ll! Four units are effective.

1'Y''ゝY'' (In the formula, Y is a polycyclic aromatic ring such as a naphthalene or anthraheptane ring when combined with a benzene ring, or a carbazole ring, benzocarbazole ring, dibendifuran ring, etc. when fused with a benzene ring) represents an atomic group necessary to form a heterocycle.R represents an optionally substituted alkyl group (e.g., methyl group, ethyl group, n-propyl group, 1so-propyl group, n-butyl group, .8 , ・C-butyl group, amyl group,
l-octyl group, benzyl group, p-chlorobenzyl group,
3.4-dichlorobenzyl group, p-methylbenzyl group,
2-phenylethyl group, α-naphthylmethyl group, β-naphthylmethyl group), aryl group (e.g. phenyl group, tolyl group, xylyl group, biphenyl group, chlorophenyl group, dichlorophenyl group, bromphenyl group, methoxyphenyl group, ethoxy phenyl group, butoxyphenyl group,
Phenoxyphenyl group, nitrophenyl group, cyanophenyl group, hydroxyphenyl group, carboxyphenyl group, N,N-dimethino!・)′minophenyl group, α, α,
α-Trifluoromethylphenyl group, methylthiophenyl group,! -f methyl group, β-naphthyl group, etc.) R2 represents R1 and a heterocyclic group (e.g., thiazolyl group, 5-nitrothiagyryl group, carbazolyl group, indolyl group, pyrrolyl group, acridyl group, benzo(blthiophenyl,
benzimidazolyl group, oxasilyl group, chlorooxasilyl group, triazolyl group, piperidyl group, pyridyl group, quinolyl group).

R, represents 0, S, -N)l; * "4" and "5" represent hydrogen, an optionally substituted alkyl group, a nitro group, a methoxy group, an ethoxy group, an acetyl group, a cyano group, or a halogen.

Z is a chain hydrocarbon necessary to form 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 (1) as a photoconductive substance constituting the photosensitive layer of an electrophotographic photoreceptor, it is also possible to obtain an excellent carrier for the azo pigment of the present invention. Only the generation ability is utilized, and carrier generation and transfer are performed using separate substances.

So-called functional portion W4. By using it as a carrier-generating material in type electrophotographic photoreceptors, it has excellent electrophotographic properties such as excellent film properties, charge retention, sensitivity, and residual potential, and has little fatigue deterioration even after repeated use. It is possible to produce an electrophotographic photoreceptor that exhibits stable characteristics without any change in the above-mentioned characteristics even when exposed to heat or light.

Specific examples of the azo pigment useful in the present invention represented by the above general formula include those having the following structural formula, but the azo pigment of the present invention is not limited thereto.

Exemplary Azo Pigments The azo pigments represented by the general formula (1) above are represented by the general formula (al,
(bl, (C), (d) (in each formula, X%n is homologous to general formula (I), formula (
cl, (m in dl is 0 or 1) 2
A tetravalent amide 7-mer compound is azotized by a conventional method, and then the corresponding Kaglar is coupled in the presence of an alkali, or the diazonium salt of the above-mentioned amine compound is converted into a boro7trate salt, a zinc chloride double salt, etc. After a single application in the form of can be synthesized into

Next, a method for synthesizing a representative example of the azo pigment used in the present invention will be shown.

Synthesis Example (Exemplary Pigment A-55) (Synthesis of P-nitrobenzaldehyde-hydrazone) P
-Nitrobenzaldehyde3. Of and hydrazine hydrate14. Obtained by dissolving in Ofi methyl alcohol 200- and heating under reflux on a water bath for about 2 hours.

Yield i 3.4 (91 Melting point 134.5-136.0
℃ (Synthesis of P-nitrobenzaldehyde-N,N-di(P-nitrobenzyl)-hydrazone) P-nitrobenzaldehyde-hydrazone 3.3t and P
- Dissolve 13.0 tf of nitrobenzyl bromide in 60 cc of dimethyl sulfoxide, drop 10 cc of 5N caustic soda solution at room temperature, and then leave to stand overnight. The precipitated reddish brown crystals were recrystallized from ethyl acetate to obtain 4.2f of orange powder.

1 point 302-304℃ (Synthesis of P-aminobenzaldehyde-N,N-di(P-aminobenzyl)- and dracine) P-nitrobenzaldehyde-N,N-di(P-nitrobenzyl)-hydrazone was dissolved in concentrated hydrochloric acid. and reduction with stannous chloride to obtain a pale yellow powder with a melting point of 209.5-211°C.

By IR (KBr tablet method), the absorption of nitro group of 1350crR disappears, and 3340on and 340
Absorption of ami7 group was observed at 0 cm-'.

(Synthesis of Exemplary Raw Material A-55) P-aminobenzaldehyde-N,N-di(P-aminobenzilated)-hydrazone (formula 1f1 below) 0°7f total 1
Dissolved in 1.0 ml of 2N hydrochloric acid and 30% of dimethylformamide to give 0.452
A solution prepared by dissolving sodium nitrite in water was added dropwise under water cooling, and the mixture was allowed to react under cooling for about 1 hour. Next, trace amounts of urea and activated carbon were added to filter out insoluble matter, thereby creating a diazonium bath.

2-hydroxy- of the following structural formula as a coupling component
Kagura-3, Of having benzo[a]carbazole as a basic skeleton.

Triethanolamine 4.0tf dimethylformamide 80+ntiCmM was used as an organic amine, and the mixture was cooled to 0 to 5°C. Next, the above diazonium salt bath solution was added dropwise to the 1 color solution, and the black paste-like liquid produced was 0 to 1
The mixture was kept at 0°C and stirred for an additional 3 hours. Generated Shen #!
It was filtered, thoroughly washed with acetone and then hot water, and heated again with acetone to obtain 3.2 tons of black powder with a slight metallic luster after drying. The melting point was 350°C or higher.

Other exemplary pigments can also be synthesized according to the above synthesis examples.

The photosensitive layer of the electrophotographic photoreceptor of the present invention includes the following types of photosensitive layers.

■ A photosensitive layer made of an azo pigment ■ A photosensitive layer in which an azo pigment is dispersed in a binder ■ A photosensitive layer in which an azo pigment is dispersed in a well-known charge transfer layer The photosensitive azo pigment of the present invention, which is coated with a charge transport layer containing a well-known charge transport substance, has an extremely high tl-absorption of visible light to near-infrared light in a range from 50 U nm to 850 nm. Generate charge carriers with efficiency.

The generated carrier can move using the azo pigment itself as a medium, but it is more preferable to move the carrier using a well-known charge transfer substance as a medium. From this point of view, the photosensitive I- forms of (1) and (2) are particularly preferred. .

Charge transfer substances are generally classified into two types: electron transfer substances and hole transfer substances, and both can be used in the photosensitive layer of the photoreceptor of the present invention, and although they have the same function, Mixtures or mixtures of substances having different functions can also be used. Examples of substances having electron transfer include electron-attracting compounds having a nitro group, cyano group, ester group, etc., and these include, for example, 2.
4.7-Dolinitrofluorenone, 2,4,5.7-
nitrated fluorenones, such as titranitrofluorenone;
Or tetracyanoquinodimethane, tetracyanoethylene, 2,4,5.7-detranitroxanthone, 2.
4.8-) Chemical adducts such as linitrothioxanthone, and molecularly controlled adducts of these Kameji-absorbing adducts can be mentioned.

In addition, as a hole transfer medium, the following compounds may be used as organic photoconductive compounds having a monovalent bond.

hydrazones C, H.

2H5 Pyrazolines (6) C2H5 Codiarylalkanes 2M5 Alkylene diamines Dibenzylanilines^1, G'0 Triphenylamines Diphenylbenzylamines Triarylalkanes CH5 CH3 Cd5 CH3 Oxadiazoles-N Anthracenes Examples include oxazoles. Other polymeric compounds Toshite, poly-N-vinylcarbazole, poly(N-vinylcarbazole)/'-nated poly-N-vinylcarbazole, poly and nylpyrene, polyvinylanthracene, polyvinylacridine, polyglycidylcarbazole, ciboribinylacenaphthylene, ethylcarbazole-formaldehyde Resins, etc. can also be used.

The carrier transfer substances are not limited to those described herein, and when used, one type or a mixture of two or more types of carrier transfer substances can be used.

The electrophotographic sensitive material according to the present invention can be manufactured according to a conventional method.

For example, an electrophotographic photoreceptor having photosensitive pjI of the type (2) above is obtained by dissolving or dispersing the azo pigment represented by the general formula (11) in an appropriate medium, and dissolving or dispersing the azo pigment on a conductive support. Nigo cloth, dried, usually 0.1 μm to several 1
It can be manufactured by forming a photosensitive layer with a thickness of 0 μm.

The medium for preparing the liquid solution includes basic solvents that dissolve tetrakisazo pigments such as n-butylamine and ethylenediamine; ethers such as tetrahydrofuran and l,4-dioxane; ketones such as dimethyl ethyl ketone and cyclohexanone; toluene; Aromatic carbonized ice confections such as xylene: Aprotic polar solvents such as N,N-dimethylformamide, acetonitrile, N-methylpyrrolidone, dimethyl sulfoxide: Alcohols such as methanol, ethanol, iglopanol: ethyl acetate, methyl acetate, methyl Media for dispersing azo pigments include esters such as cellosolve acetate; and chlorinated hydrocarbons such as dichloroethane and chloroform.

For the dispersion using a medium for dispersing the azo pigment, the particle size of the azo pigment is 5 μm or less, preferably 3 μm or less, and 1 μm or less for breakthrough.
It is necessary to make the particles smaller than μm.

Further, as the conductive support on which the photosensitive layer is formed, any of those employed in well-known single-child photographic photoreceptors can be used.

Specifically, for example, a metal drum made of aluminum, copper, etc.
Examples include sheets, laminates, and vapor-deposited materials of these metal foils.

Further examples include plastic films, plastic drums, paper, etc. which are coated with a conductive substance IX such as metal powder, carbon black, iodized steel, or polymer electrolyte together with a suitable binder to conductivity treatment.

Examples include 4% glass sheets and drums that contain conductive substances such as copper, metal powder, carbon black, and carbon fiber.

If a binder is dissolved in the coating liquid used to form the photosensitive layer of the type (2) above, an electrophotographic photoreceptor having the photosensitive layer of the type (2) can be produced.

In this case, i2i! Preferably, the medium for the fabric solution is one that dissolves the binder.

As binders, polymers and copolymers of vinyl compounds such as styrene, RNM vinyl, acrylic esters, methacrylic esters, phenoxy resins, polysulfones, arylate a fats, polycarbonates, polyesters, cellulose esters, cellulose ethers, urethane resins, Examples include various polymers such as epoxy resins and acrylic polyol resins.

The amount of binder used is usually 0°1 to 5% relative to the azo pigment.
The range is twice the weight.

In addition, in forming this type of photosensitive layer,
It is preferable that the azo pigment be present in the binder in the form of fine particles, for example, with a particle size of 3 μm or less, particularly 1 μm or less.

Similarly, by dissolving a charge transfer medium in the coating liquid used to form the photosensitive layer of the type (2) above, an electrophotographic photoreceptor having the photosensitive layer of the type (2) above can be produced.

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

Apart from charge transport media which can themselves be used as binders, such as polyvinylcarbazole and polyglycidylcarbazole, it is preferred to use other binders.

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

In this case, the amount of binder used is usually 5
The amount of the charge transport medium used is usually 0.2 to 3.0 times, preferably 0.3 to 1.2 times the weight of the binder. In the case of a charge transfer medium that can itself be used as a binder,
For the azo pigments of the present invention, it is usually 3 to 153 [used for electronic purposes].

In this type of photosensitive layer, it is preferable that the azo pigment be present in the form of fine particles in the transport medium and the binder, as in the photosensitive layer of tie 1 in item (1) above.

To form a charge transport layer on the photosensitive layer of the type (1) to (2) above, the coating solution obtained by dissolving the charge S moving medium in an appropriate medium is dropped onto a cloth and dried to form a charge transfer layer. It is possible to manufacture an electrophotographic photoreceptor having the following.

In this case, the photosensitive layers of types (1) to (4) above serve as charge generation layers.

The charge transfer layer 1- does not necessarily need to be provided above the charge generation layer, but 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 photosensitive layer described in (2) above. That is, the azo pigment removed from the mineral subliquid for forming the photosensitive layer described in (1) may be used as the coating liquid. Typically the charge transport layer is 5-50 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 dyes that form charge-transferring bodies with the organic photoconductive material.

Examples of Lewis acids include quinones such as chloranil, 2,3-dichloro-1,4-naphthoquinone, 2-methylanthraquinone, 1-nitroanthraquinone, 1-chloro-5-nitroanthraquinone, 2-chloroanthraquinone, and phenanthrenequinone. aldehydes such as 4-nitrobenzaldehyde)'a,9-benzoylanthracene, indanedione, 3,5-dinitrobenzophenone, a,a'.

5. Ketones such as 5'-tetranitrobenzophenone,
Acid anhydrides such as phthalic anhydride and 4-chlornaphthalanhydride; cyano compounds such as tetracyanoethyln, terephthalmalonitrile, and 4-nitrobenzalmalonitrile; 3-penzalphthalide, 3-(α-cyano-P- Examples include electron-withdrawing compounds such as nitropenzale) phthalide and 3-(a-cyano-P-nitropenzale)phthalide.

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

In addition, inorganic photoconductive fine particles such as selenium and selenium-arsenic alloys, organic photoconductive pigments such as copper 7 ria cyanine M materials, and perylene pigments may also 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 formability, flexibility, % mechanical frequency, and the like.

As plasticizers, phthalate esters, phosphate esters,
Examples include epoxy compounds, chlorinated paraffins, chlorinated fatty acid esters, and aromatic compounds such as methylnaphthalene. Moreover, it goes without saying that an adhesive layer, an intermediate layer, and a transparent insulating layer may be included as necessary.

The photoreceptor using the azo pigment of the present invention has high sensitivity and good color sensitivity, and when used repeatedly, there is little change in sensitivity and chargeability, and there is little light fatigue, and it is extremely durable. It is something.

Furthermore, the photoreceptor of the present invention can be widely used in electrophotographic applications such as photoreceptors for glitters using lasers, cathode ray tubes (CRTs), and light emitting diodes (LEDs) as light sources in addition to electrophotographic copying machines.

Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to the following examples as long as the gist of the invention is not exceeded.

Example 1 Polyester film laminated with aluminum foil (Alvet 85 manufactured by Daido Kako Co., Ltd., aluminum film thickness lOμ
) on a conductive support consisting of a vinyl chloride:vinyl acetate:maleic anhydride copolymer (Eslec M manufactured by Tanezu Kagaku Co., Ltd.).
Azo pigment 2F of exemplified azo pigment A-37 and polyarylate resin (U-100 manufactured by Yunichika) 29 were mixed with 1,2-dichloroethane 100 to form an intermediate layer having a thickness of 0.05 μm. - The azo obstetric dispersion obtained by dispersing in paint contisi soda for about 1 hour is coated on the intermediate layer so that the film thickness after drying is 0.5 μm, and dried to form a carrier. Generation j @ total formation, and further carrier transfer substance N,N-dipendylaminopenzaldehyde-1,1-diphenylhydrazone 52 with polyarylate resin 7t% 1$2-dichloroethane 5
An electrophotographic photoreceptor of the present invention was prepared by coating and drying a bath solution in which 0- was dissolved in a carrier transport layer so as to have a film thickness of 12 μm after drying. After storing the photoreceptor at room temperature at 30° C. for one week in a dark place, the electrophotographic photoreceptor was loaded into an electrostatic paper tester [5P-428J (manufactured by Kawaguchi! Ki Seisakusho) and the following characteristic tests were conducted.

That is, by applying a voltage of -6 KV to a charger and charging the photosensitive layer t-g by corona discharge for 5 seconds, the potential at that time Vo(-V
) Then, with the illuminance on the surface of the photosensitive layer M being 301 ux, irradiation with light from a halogen lamp is performed to reduce the surface potential of the photosensitive layer to 1/2 by 1' exposure amount B = y (lux seconds) I asked for

Furthermore, the exposure amount Eso (lux・
(excerpt) was requested. Similar experiments were repeated 500 times to examine the continuous use characteristics. Furthermore, except for this continuous operation,
300 using a tungsten lung as a light source for static elimination light
This was followed by irradiation with a halogen lamp for 0.3 seconds at lux to completely reduce the residual potential to zero. The results are shown in Table 1.

Table 1 Examples 2 to 6 Examples of carrier generating substances include azo pigment A-6,
A total of five types of electrophotographic photoreceptors were prepared in the same manner as in Example 1, except that azo pigments A-12, A-45, A-48, and B-4 were used, and each of them was treated as in Example 1. A similar characteristic test was conducted.

The results are shown in Table 2.

(The following is a blank space) Example 7 A 0.4 μm thick subbing layer made of vinegar vinyl resin was formed on the surface of a 1M diameter cod drum with a mirror-like surface made of aluminum and coated with 1 exemplified azo pigment A. -502tk1.2-
A fractional liquid obtained by dispersing for about 3 hours using 100ml of dichloroethane and a paint condesigoner,
A carrier generating layer was formed on the intermediate layer by drying lIL'; f5 so that the film thickness after drying was about 0.5 μm.

On this carrier generation layer, a carrier transfer substance having the structural formula N,N-diethylaminobe/dualdehyde-1-phenyl-nearylhydrazone 10F
Polycarbonate resin (manufactured in large quantity Panlite L-125)
0) A solution of 12f and 1,2-dichloroethane 100- is applied and dried to a film thickness of 15 μm after drying to form a carrier transfer layer, thereby producing a drum-type electrophotographic photoreceptor according to the present invention. Created.

When this electrophotographic photoreceptor was installed in a modified version of a commercially available IJudge type electrophotographic copying machine and used to form copied images, it was found that the contrast was excellent and a clear visible image that was faithful to the original was obtained. It was done. The image capture was repeated 1,000 times, but until the end, a visible image equivalent to the first image was obtained.

Example 8 The reflection spectrum of the drum-type electrophotographic photoreceptor obtained in Example 7 was analyzed using a spectrophotometer (Shimadzu UV-36
5) Adding Yoshi(lIIJ), this graph shows that the maximum absorption wavelength in the visible region of this photoreceptor is 630 nm and 750 nm.
It turned out to be around nm. Furthermore, 635 nm, 770
When the spectral sensitivity at nm was measured using a monochrome meter, the optical energy required to reduce the potential by half was 3.2.
erg/d (635 nm), 4.8 erg/cI
1 (770 nm), and the photoreceptor was sufficiently usable even when a laser or a light emitting diode was used as a light source. It was also found that any part of the photoconductor showed the energy value required to reduce the potential by half, indicating that the photoconductor had uniform sensitivity.

Example work 4 On a grained and roughened M board, a styrene:methyl methacrylate: methacrylic acid co-particle composite (styrene: methyl methacrylate = 2:1 weight ratio, acid value 320) and exemplified azo pigment C-9 were applied. and N,N-dibenzylaminophenyl-
1-Methyl-1-phenylhydrazone Q1.5: 0
．． 2:1.0, dissolved (resin, resin component, hydrazone compound) and dispersed (azo pigment) in dioxane, and coated and dried to prepare a single layer type photoreceptor with a film thickness of 6 μm.

The photoreceptor of the present invention thus prepared was subjected to an electrophotographic property test using the electrostatic paper tester described above, and the results were as follows.

Applied voltage +6 KV Vo = 420 (+V
)E-'z = 3.0 (1uxs seconds) Exo=
8.5 (luxs seconds) Also, this photoreceptor is visualized with a developer (toner), and then an alkaline processing water bath solution (for example, 3% triethanolamine, 10% ammonium chloride,
When treated with polyethylene glycol (polyethylene glycol with an average molecular weight of 1190 to 210), the non-toner-adhered area is easily eluted, and then a printing original plate can be easily created by washing with water containing silica powder. was completed.

It was found that when offset printing was performed using this original plate, it could withstand printing of approximately 100,000 sheets.

In addition, in order to obtain a toner visible image (light source: halogen rung)
The optimal four-way inference was 2 seconds at 200 lux.

In addition, when creating the printing plate, direct plate making was performed without using any base material.

Claims (4)

[Claims] (1) An electrophotographic photoreceptor comprising a photosensitive layer containing an azo pigment represented by the following general formula (I) on a conductive support. ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(I) (In the formula, R is hydrogen, a lower alkyl group, a phenyl group that may contain a substituent, a styryl group, and X is hydrogen, an alkyl group, an allyl group, There are heterocyclic residues, phenyl groups that may contain substituents, ▲numerical formulas, chemical formulas, tables, etc.▼, and n
is 0 or 1, and Cp represents a coupler residue. ) (2) The electrophotography according to claim 1, wherein 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). Photoreceptor. (3) The electrophotographic photoreceptor according to claim 1, wherein the azo pigment represented by the general formula (I) is a compound represented by the following structural formula. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, X, Cp, and n are synonymous with the first term.) (4) The electrophotographic photoreceptor according to claim 1, wherein the azo pigment represented by the general formula (I) is a compound represented by the following structural formula. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, X, Cp, and n are synonymous with the first term, and m is 0 or 1.)