JPS6123155A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body which has high sensitivity and small residual potential, maintains the initial characteristics without change even after repetitive use and has excellent durability by using a specific bisazo pigment as a photoconductive material forming a photosensitive layer. CONSTITUTION:The coating liquid obtd. by dissolving or dispersing the azo pigment expressed by the formula in a suitable medium is coated on a conductive base and is dried to form the photosensitive layer. The azo pigment expressed by the formula is synthesized by converting the diamine expressed by H2N-A- NH2 to tetrazo and coupling the corresponding coupler in the presence of an alkali or isolating once the tetrazonium salt of diamine in the form of borofluoride salt or zinc chloride double salt then coupling the same with the coupler in the presence of the alkali in a solvent such as N,N-dimethyl formamide or dimethyl sulfoxide.

Description

DETAILED DESCRIPTION OF THE INVENTION (5) Industrial Application Field The present invention relates to an electrophotographic photoreceptor, and more particularly, to a novel electrophotographic photoreceptor having a photosensitive layer containing azo compound gold. More specifically, the present invention relates to a highly durable electrophotographic photoreceptor that has high sensitivity and is suitable for repeated use.

(B) Prior Art and its Problems Conventionally, electrophotographic photoreceptors having a photosensitive layer made of an inorganic photoconductor such as selenium, zinc oxide, or cadmium sulfide have been widely known.

However, these are not necessarily satisfactory in terms of sensitivity, thermal stability, moisture resistance, durability, etc. In addition, selenium and cadmium sulfide are particularly toxic, so there are restrictions in production and handling. On the other hand, an electrophotographic photoreceptor having a photosensitive layer containing an organic derivative as a main component is relatively easy to manufacture, inexpensive, easy to handle, and is generally selenium-sensitive. It has many advantages1, such as being less thermally stable than the body, and has attracted much attention in recent years.

Poly-N-vinylcarbazole is well known as such an organic photoconductive compound, and 2.4.
7-) Electrophotographic photoreceptors having a photosensitive layer containing as a main component a charge transfer complex formed with a Lewis acid such as dinitro-9-fluorenof are not necessarily satisfactory in terms of sensitivity and durability.

On the other hand, layered or dispersed function-separated photoreceptors, in which the carrier generation function and the carrier transport function are assigned to separate substances, have a wide range of materials to choose from, and have a wide range of materials to choose from, with different charging characteristics, sensitivity, and durability. An electrophotographic photoreceptor that has any characteristic FW in terms of electrophotographic properties such as gender? It has the advantage of being relatively easy to create.

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

For example, an electrophotographic photoreceptor having a photosensitive layer that combines a carrier generation layer made of amorphous ceramic and a carrier transfer layer mainly composed of poly-N-vinylcarbazole has been put into practical use.

However, the carrier generation layer made of amorphous Cele/C has a disadvantage of poor durability (I-v).

In addition, various proposals have been made for the use of 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 are not necessarily satisfactory in terms of characteristics such as sensitivity, residual potential, and stability when used repeatedly, and the selection range of carrier transfer substances is also limited. The reality is that nothing that fully satisfies the wide range of requirements has yet to be obtained.

(C) Purpose of the Invention The present invention was made in view of the above-mentioned circumstances, and its main purpose is to provide electrophotography containing an azo pigment that is stable to heat and materials and has excellent carrier generation ability. The entire photoreceptor is to be provided.

Another object of the present invention is to provide high sensitivity, low residual potential,
Another object of the present invention is to provide an electrophotographic photoreceptor having excellent durability and whose characteristics do not change even after repeated use.

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

(To) Structure of the Invention As a result of intensive research to achieve the above objectives, the present inventor has discovered the following:
Can the azo pigment represented by the following general formula (1) act as an active ingredient of a photoreceptor? Heading, book (in the formula, Afj
: 2 bonded to N atom forming an azo association with O atom
X is 10-1-S-1-NH- and %Z is an atom necessary to form a substituted or unsubstituted aromatic hydrocarbon or a substituted or unsubstituted heterocycle 5. In a group. R, R'u water, furkyl, haloken, nitro,
Sulfonic acid, alkoxy. ) <Specific Configuration of the Invention> The specific configuration of the present invention will be described in detail below.

In the present invention, it is advantageous to use the bisazo pigment represented by the general formula (1) as a photoconductive substance forming the photosensitive layer of an electrophotographic photoreceptor, and the excellent carrier generation of the bisazo pigment of the present invention is advantageous. The generation and movement of carriers are performed using separate materials, and by using them as gear generation materials in so-called functional separation plate photoreceptors, the film has excellent physical properties such as charge retention, sensitivity, residual potential, etc. To create an electrophotographic material which has excellent electrophotographic properties, exhibits little fatigue deterioration even after repeated use, and is capable of exhibiting all of the stable properties without changing the above-mentioned properties even when exposed to heat or heat. I can do it.

Specific examples of the azo pigment useful in the present invention represented by the general formula (11) include those having the following structural formula, but the bisazo pigment of the present invention is not limited to this. .

Exemplary azo pigment H5;8;8 The azo pigment represented by the general formula (11) has the general formula H2N
A diamine represented by -A-NH2 (the person in the formula has the same meaning as above)? Tetrazotization is carried out in a conventional manner, followed by coupling in the presence of the corresponding coupler t alkali, or
Or the tetrazonium salt of the previous diamine? After isolation in the form of borofluoride salt or azinc double salt, etc.
a suitable solvent, such as N,N-dimethylformamide;
It can be easily synthesized by coupling with a coupler in a solvent such as dimethyl sulfoxide in the presence of an alkali.

Next, the synthesis method for five representative examples of the azo pigment used in the present invention will be shown.

Synthesis Example 1 (Exemplary Compound A7) 3.3'-dichlorobe/zidine 2.59 (10 m
Mole) K6tnt was added to a mixture of concentrated hydrochloric acid and water at 20°C and dispersed, and 1.4 f (21 mmole) of sodium nitrite was dissolved in water. Made it react. Next is activated charcoal? The mixture was added and filtered to obtain a tetrazonium water bath.

As a coupling component, 2-S290℃ shown by the following formula
), triethylamine 4 as an organic amine? (40m
mole) iDMF20- and DM 8020 ml and cooled to 0-5°C. Next, the above diazonium salt solution was added dropwise to the Kaglar solution, and the resulting blue-purple paste solution was kept at tO to 10°C and stirred for an additional 3 hours. The resulting precipitate was filtered, thoroughly washed with acetone and then water, and ethyl acetate was extracted using a Soxhlet extractor, and used as a washing liquid. After drying, a dark purple powder of 4.82 mm was obtained.

The melting point was 350°C or higher.

Synthesis Example 2 (Illustrated Compound Boiled 17) In substantially the same manner as in Synthesis Example 1, nato-dizonium salt water MWk
The coupler component is expressed by the following formula (melting point 162~
163.5°C) The coupling reaction was carried out under water cooling using triethanolamine as the amine and a mixed solvent of DMF and water as the reaction solvent, and a purple powder was obtained using the same purification method as in the synthesis example. . Melting point is 312℃ (decomposition)
Met. Other azo pigments of the present invention can also be obtained according to the above synthesis examples.

In the electrophotographic photoreceptor of the present invention, various types of photosensitive layers containing one or more azo pigments represented by the general formula (11) are well known, but the electrophotographic photoreceptor of the present invention The photosensitive layer of the photoreceptor may be in any of these types, but is usually of the type shown below.

■ Photosensitive layer consisting of azo pigment ■ Sensitive yfSr* with azo pigment dispersed in the entire binder
■ A photosensitive layer in which azo pigment 7 is dispersed in the same known charge transfer substance. Photosensitive layer The azo pigment represented by the above general formula generates charge carriers with extremely high efficiency when it absorbs the original.

Although the generated carriers can be transferred as an azo pigment medium, it is preferable to transfer them as a well known charge transfer material medium. From this point of view, photosensitive layers having the forms (1) and (2) are particularly preferred.

Charge transfer substances are generally classified into two types: electron transfer substances and hole transfer substances, but both can be used in the photosensitive layer of the photoreceptor of the present invention, and have the same type of function! Mixtures of substances having different functions or mixtures of substances having different functions can also be used. Examples of substances that transfer electrons (kW) include electron-withdrawing compounds having electron-withdrawing groups such as nitro groups, cyano groups, and ester groups.
2,4゜7-dolinitofluorenone, 2,4,5
．． Nitrated fluorenone such as 7-titranitrofluorole/7V, or compounds such as tetracyanoquinodimethane, tetracyanoethylene, 2,4,5.7-titranitroxanthone, 2,4.8-)linitrothioxanthone Also, polymerized products of these molecule-absorbing compounds can be used.

Examples of electron-donating organic photoconductive compounds that can be used as a transport medium for particles and holes include the following.

Hydoshizones, pyrazolines, diarylalka-7s, alkyl-/7-amino-7s, triphenylamines, sulfurbenzylamines, 7-series triarylpurcans, 0H5 (5; Thadiazoles, a/toshi7anes, tll, oxazoles, etc.) Other polymerized compounds 5.j-'IJ-N-vinylcarbazole, halogenated polyIJ'N-vinylcarbazole, polyvinylpyrene,
Polyvinylanthracene, polyvinylacridine, polyglycylcarbazole, polyvinylacenaphthyleno,
Ethyl carbazole-formaldehyde resins, etc. can also be used.

The carrier transfer substances are not limited to those described here, and when used, 71 types of carrier transfer substances or a mixture of two or more types can be used.

The electrophotographic sensitive material of the present invention can be manufactured according to a conventional method. For example, an electrophotographic photoreceptor having a photosensitive layer of the type (2) above can be prepared by coating a coating solution obtained by dissolving or dispersing an azo pigment represented by the general formula (11) in a suitable medium on a conductive support; KLp can be produced by drying and forming a photosensitive layer with a thickness of usually several μm to several tens of μm.

As a medium for preparing the coating solution, a basic solvent that dissolves an azo compound such as n-butylamine/, ethylenediamine, or an ether such as tetrahydrofuraf, 1,4-dioxa7, or a ketone such as methyl ethyl keto/, cyclohexano7, etc. Class: Aromatic hydrocarbons such as toluene and xylene: N
, N-dimethylformamide, acetonitrile, N-methylpyrrolidone, dimethyl sulfoxide, and other aprotic polar solvents; methanol, ethanol, ingropanol, and other alcohols; ethyl acetate, methyl acetate, methyl cellosolve acetate, and other esters, dichloroethane The medium in which the azo pigment is dispersed, such as a chlorinated hydrocarbon such as chloroform, is removed.

When using a medium for dispersing the azo pigment, it is necessary to micronize the azo pigment to a particle size of 5 μm or less, preferably 1 μm or less.

Further, as the conductive support on which the photosensitive layer is formed, any of those employed in the well-known photosensitive element 'I' may be used.

Specifically, aluminum, copper, a plastic drum or sheet with aluminium-coated surface deposited, or a laminate sheet of metal foil may be used.

Examples include glass films, glass drums, and papers which are coated with a conductive substance such as powder, metal powder, carbon black, copper iodide, or polymer electrolyte together with a suitable binder to conductivity treatment.

By dissolving the binder 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, the medium of the coating liquid is preferably one that dissolves the binder. As a binder, styrene,
Polymers and copolymers of vinyl compounds such as vinyl acetate, acrylic esters, methacrylic esters, phenoxy resins, polysulfones, arylate resins, polycarbonates, polyesters, cellulose ethers, cellulose ethers, urethane resins, epoxy resins, acrylic polyol resins, etc. Examples include various polymers.

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 r,
Azo pigment? It is preferable that the particles be present in the form of fine particles, for example, with a particle diameter of 3 μm or less, particularly 1 μm or less.

Similarly, if a charge transfer medium is dissolved in the coating liquid used to form the photosensitive layer of the type (2) above, the photosensitive layer of the type (2) can be formed. Do you have an electronic photographic feeling element? Manufacture can be done carefully.

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

Although the charge transfer medium of polyvinylcarbazole and polyglycidylcarbazole itself can be used as a binder, 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 0 for the azo pigment.
．． The amount of the charge transport medium used is generally 0.2 to 1.5 times the weight of the binder, preferably 0.3 to 1.2 times the weight of the binder.

In the case of a charge transport medium which itself can be used as a binder, it is usually used from 1 to 10 times the weight of the azo pigment.

Like the photosensitive layer of type (2) above, this type of photosensitive layer is also preferably made of bisazo pigment km present in the form of fine particles in the transport medium and the binder.

If a coating solution obtained by dissolving a charge transfer medium in a suitable medium is coated and dried to form a charge transfer layer on the photosensitive layer of the type (1) to (2) above, the photosensitive layer of the type (1) can be formed. It is possible to produce 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 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 from the viewpoint of durability.

The charge transfer layer is formed in the same manner as the photosensitive layer described in (1) above. That is, the azo pigment may be removed from the coating solution for forming the sensitizing element described in (1) above, and the coating solution may be used as a coating solution.

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 α-transfer complexes with the M-molecules.

Examples of Lewis acids include chloranil, 2,3-dichloro-1,4-naphthoquino, 2-methyla/traquino/
, 1-nitroanthraquinone, 1-chloro-5-troanthraquinone, 2-chlorua/traquinone, fena/
Quinoys such as Torenki 7/, aldehydes such as 4-nitrobenzaldehyde, 9-pencilure/torase/
, inda/dione, 3,5-dinitrobenzyphenone,
3.3'.

Ketones such as 5,5'-tetranitrobenzophenone,
Acid anhydrides such as phthalic anhydride and 4-chloronaphthalic anhydride; siteno compounds such as tetracyanoethyln, terephthalmalonitrile, and 4-nitrobenzalmalonnitrile; 3-benzalphthalide, 3-(a-cyano-P- Examples include tetrad-attractive compounds such as nitrobenzal) phthalide and 3-(a-7anoP-nitrobenzal)7thalides.

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

In addition, organic conductive pigments such as photoconductive fine particles such as selenium and selenium/arsenic alloys, phthalocyanine pigments, and berylleno pigments may also be contained.

Further, the photosensitive layer of the electrophotographic photoreceptor of the present invention may contain a known plasticizer in order to improve film formability, sinterability, and mechanical strength.

Examples of plasticizers include phthalate esters, phosphate esters,
Examples include aromatic compounds such as epoxy f-hydrocarbons, chlorine-1-hydrafin, chlorinated fatty acid esters, and methylnaphtalif.

Also, if necessary, adhesive layer, intermediate layer, light insulation layer? Needless to say, it may be included.

The photoreceptor using the azo pigment of the present invention is sensitive to the stomach and has good color sensitivity, and when used repeatedly, there is little change in sensitivity and chargeability, there is little light fatigue, and it has excellent durability. It is something.

Furthermore, the photoreceptor of the present invention can be used not only for electrophotographic copying but also for laser, cathode ray tube (CI), light emitting diode (LED), etc.
It can also be widely used in electronic applications such as photoreceptors in printers used as light sources and printing plates for off-cent printing.

(E) Examples 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 unless the gist of the invention is overloaded.

Example 1 Polyester film laminated with aluminum foil (Albet 85 manufactured by Daido Kako Co., Ltd., aluminum 1 thickness 10
μ) on a conductive support consisting of alcohol +'t'
4 sex f (c' 7 (East"BJ-<M 8000)
A subbing adhesive layer R with a film thickness of 0.05 μm is formed, and exemplified azo pigment type 2 12 and polyarylate resin (U made by Unitika Co., Ltd.) are formed.
-100) 11, tl, 2-dichloroethane/100- and azo-f-hyde compound dispersion obtained by dispersing in a bay/container for about 1 hour, film thickness after drying on the intermediate layer. It was coated and dried to form a carrier generation layer with a thickness of 0.5μ.

Furthermore, 1,2-dichloroeme 150 along with carrier transfer substance N,N-dibenzylaminobenzaldehyde 1,1-diphenylhydrazone 52r polyarylate resin 77
The fnlK bath solution was dissolved and the fc bath solution was coated and dried so that the film thickness after drying was 12 μm to form a carrier moving layer, and the "low-weighted material of the present invention" was plotted.

After storing Honkan-Kutai in a dark place at room temperature 30 degrees Celsius for one hour.

This electrophotographic sensitive element was tested using electrostatic paper tester 1'-8P-428.
'' (newly manufactured by Kawaguchi Electric) and conducted the following characteristic tests.

That is, the voltage of the charger -6KV? The photosensitive layer was charged by corona discharge for 5 seconds, and the potential at that time Vo (-V
), and then, with the illuminance on the surface of the photosensitive layer being 301ux, the exposure foot E7 ( required to attenuate the surface potential of the photosensitive layer to 1 level by irradiating the light from the norogen lamp with an illuminance of 301ux)
luxΦsec)r was calculated.

The surface potential after exposure with an exposure amount of fC-30lux·sec, that is, the residual potential E50(-V)y was determined.

Similar measurements were repeated 500 times. In addition, a tungsten lamp was used as a light source to remove residual potential.
Further exposure was performed for 0.3 seconds at lux to completely bring the residual potential to OK.

The results are shown in Table 1.

Table 1 Examples 2 to 10 Examples of carrier-generating substances: Azoganekoma 4, Bi 6, Hen 7, & 10, A 12, Ya 16, A 19
A total of 9 pieces of electrophotographic photoreceptors were prepared in the same manner as in the examples, and the same characteristic tests were carried out on each piece. The results were as shown in the fA2 table.

Laminate Example 11 On the surface of a drum made of aluminum F with a diameter of 80 m, an example of azo additive No. 202y and vinyl chloride/vinyl acetate (87:13) co-organized 1f'in-Buti A/'7 Mi730 +nr and tetrahydrofuranf 0 In addition to a mixture of fragrances, Bay 7 Toko/Desi Sonar is used to sprinkle Gino for about 2 hours. I command, Ill;! A carrier generating layer was formed by coating and drying to a thickness of ~0.3μ.

On this carrier generation layer, a carrier transfer substance N,N-diethylaminobenzaldehyde-1-(P-)ylphenyl)-1 shown by the structural formula
- Allyl hydrazo y 10 g'□yr: bath solution t dissolved in monochlorobenzene 100 tnl together with recarbonate resin (Hanrai l-1250 manufactured by Teijin) 122, I sea urchin coating with a film thickness of 15μ after drying, ffIqZ dried,
No career move? A drum-type photographic photoreceptor was fabricated.

When we applied this electronic 4-photoconductor to our modified version of a commercially available cartridge Ninneko Yoma copying machine and produced a copy image, we were able to obtain a clear visible image with high contrast and faithful to the JJA scheme. Obtained. Although the copying process was repeated 9 times for 1000 times, a visible image equivalent to that of the first copy was obtained until the end.

Example 12 The reflection spectrum of the Atsuko drum photographic photoreceptor obtained in Example 11 was measured using an integrating sphere and a divisor (UV-36 manufactured by Shimadzu).
5) Measure from 580nm to 680nm.
It was found that there was a large absorption in the vicinity of 1. The spectral sensitivity at 630 nm and 670 nm was measured using a monochromator.

The energy required to halve the a-position is approximately 4.5 mm for both wavelengths. Owner
It was found that the photoreceptor had a very high g/+- value and could be used in both a laser and a light emitting diode as a light source.

Example 13 A styrene: methyl methacrylate: methacrylic acid coelectrolyte (acid value 185), exemplary compound 35, and diethylamino-benzaldehyde were placed on a grained, surface-oxidized M plate.
N-phenyl-N-4-ethylpenzylhydrazone'k
Blended at a weight ratio of 1.5: 0.2: 1.0,
A dispersion bath liquid in which the resin component, hydrazo compound and azo compound were dissolved and dispersed in dioxa was coated and dried to prepare a single layer type photoreceptor with a film thickness of 6 μm.

The photoreceptor thus prepared was subjected to an electrophotographic property test using the electrostatic paper tester described above.

Applied voltage +6y Vo = 420 (+V) Scream = 6 (1uxe
seconds).

Also, the photosensitive material is visualized using a developer (toner).

Then add an alkaline processing solution (e.g. 3% triethanolamine 10 ammonium carbonate and 20% average molecular weight 19
When treated with polyethylene glycol (0 to 210),
The toner-free areas were easily removed from the bath, and then washed with water containing sodium silicate, thereby making it possible to easily prepare a printing original plate.

After seven offset printings using this original plate, we found a leather that could withstand printing on approximately 100,000 sheets.

In addition, in order to obtain a toner visible image (light source: halogen/lamp)
The optimum exposure was 1.0 seconds at 1501 ux.

Also, the original printing version? When creating the plate, direct plate making was performed without using any base material.

(G) Effects of the Invention The electrophotographic photoreceptor of the present invention uses a new bisazo pigment, and has high sensitivity, good color sensitivity, and excellent durability. have

These performances? M is excellent for use with printers and offset printing plates that use CfLT, LED, laser, halogen lamps, etc. as light sources.

-371°

Claims (12)

[Claims] (1) An electrophotographic photoreceptor comprising a photosensitive layer containing a bisazo pigment represented by the following general formula (I) on a conductive support. ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・( I
) (In the formula, A is a divalent residue bonded to the N atom forming an azo with the C atom, and X is -O-, -S-, -N
H-, Z is a substituted or unsubstituted aromatic hydrocarbon or an atomic group necessary to form a substituted or unsubstituted heterocycle, R and R' are hydrogen, alkyl, halogen, nitro, Sulfonic acid, alkoxy. ) (2) The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer contains a carrier transfer substance and a carrier generating substance, and the carrier generating substance is a bisazo pigment represented by the general formula (I). . (3) The electrophotographic photoreceptor according to claim 1, wherein the bisazo 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, m and n are 0 or 1, and X, R, R', and Z are synonymous with the first term.) (4) The electrophotographic photoreceptor according to claim 1, wherein the bisazo 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, Y_1, Y_2, Y_3, Y_4 are hydrogen, halogen, lower alkyl, methoxy, ethoxy, nitro, which may be the same or different, and X, R, R', Z is synonymous with the first term.) (5) The electrophotographic photoreceptor according to claim 1, wherein the bisazo 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, W is hydrogen, halogen, cyano, and X, R, R
', Z are synonymous with the first term. ) (6) The electrophotographic photoreceptor according to claim 1, wherein the bisazo 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' is -O-, -S-, -NH-,
, R', and Z have the same meanings as the first term. ) (7) The electrophotographic photoreceptor according to claim 1, wherein the bisazo 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, R_1 is hydrogen, lower alkyl, allyl, propenyl, benzyl which may have a substituent, phenyl which may have a substituent, , R', and Z are synonymous with the first term.) (8) The electrophotographic photoreceptor according to claim 1, wherein the bisazo 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, R, R', and Z are synonymous with the first term.) (9) The electrophotographic photoreceptor according to claim 1, wherein the bisazo 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, R_2 is hydrogen, alkyl, allyl, propargyl,
is benzyl which may have a substituent, and X'' is -O
-, -S-, and X, R, R', and Z have the same meanings as in the first term. (10) Claim 1, wherein the bisazo pigment represented by the general formula (I) is a compound represented by the following structural formula:
The electrophotographic photoreceptor described in . ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, X, R, R', and Z are synonymous with the first term.) (11) Claim 1, wherein the bisazo pigment represented by the general formula (I) is a compound represented by the following structural formula:
The electrophotographic photoreceptor described in . ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R_3 is hydrogen, lower alkyl, allyl, propargyl, benzyl which may have a substituent,
R, R', and Z have the same meanings as in the first term. ) (12) Claim 1, wherein the bisazo pigment represented by the general formula (I) is a compound represented by the following structural formula:
The electrophotographic photoreceptor described in . ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R_4 and R_5 are hydrogen, halogen, alkyl,
methoxy and nitro, and X, R, R', and Z have the same meanings as in the first term. )