JPH04116562A - Electrophotographic sensitive body, electrophotographic device having this electrophotographic sensitive body and facsimile - Google Patents

Abstract

PURPOSE:To obtain a practicable high-sensitivity characteristic and the stable potential characteristic in repetitive use by incorporating a specific disazo pigment into a photosensitive layer. CONSTITUTION:The disazo pigment expressed by formula I is incorporated into the photosensitive layer. In the formula I, Y denotes the atom group necessary for forming an arom. hydrocarbon ring or heterocycle by condensing with a pyrazine ring, A1 and A2 denote a residual coupler group having the phenolic hydroxyl group expressed by formula II. In the formula II, X denotes the residual group necessary for forming an arom. hydrocarbon polyring or heterocycle by condensing with a benzene ring; Z denotes an oxygen atom or sulfur atom; R1 and R2 denote a hydrogen atom or alkyl group, etc., which may have a substituent. The excellent sensitivity and potential stability at the time of the repetitive use are obtd. in this way.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to an electrophotographic photoreceptor, an electrophotographic device equipped with the electrophotographic photoreceptor, and a facsimile, and more particularly, to a photoreceptor containing a disazo pigment having a specific structure. The present invention relates to an electrophotographic photoreceptor having a layer, an electrophotographic apparatus equipped with the electrophotographic photoreceptor, and a facsimile.

[Prior Art] Conventionally, inorganic photoconductive substances such as selenium, cadmium sulfide, and zinc oxide have been widely used as electrophotographic photoreceptors.

On the other hand, electrophotographic photoreceptors made of organic photoconductive substances include photoconductive polymers typified by poly-N-vinylcarbazole and 2,5-bis(p-diethylaminophenyl)-1,3,4-oxadi Those using low-molecular organic photoconductive substances such as azoles, and those in which such organic photoconductive substances are combined with various dyes and pigments are known.

Electrophotographic photoreceptors using organic photoconductive substances have good film-forming properties and can be produced by coating, so they have the advantage of providing extremely highly productive and inexpensive photoreceptors. Furthermore, it has the advantage that color sensitivity can be freely controlled by selecting the dyes and pigments used, and a wide range of studies have been conducted to date. In particular, recent developments have led to the development of functionally separated photoreceptors in which a charge generation layer containing an organic photoconductive dye or pigment is laminated with a charge transport layer containing the aforementioned photoconductive polymer or low-molecular organic photoconductive substance. Significant improvements have been made in the sensitivity and durability, which were considered to be shortcomings of conventional organic electrophotographic photoreceptors.

Azo pigments exhibit excellent photoconductivity, and compounds with various properties can be easily obtained by combining the azo component and coupler component, so many compounds have been proposed so far, such as Japanese Patent Publication No. 62-295965
No. 1, JP-A-62296147, JP-A-63-
284555, JP-A-64-2054, JP-A-64-2055, etc. are already known.

However, electrophotographic photoreceptors using conventional disazo pigments are not necessarily satisfactory in terms of sensitivity and potential stability during repeated use, and only polar (
Only kana materials are used.

[Problem to be Solved by the Invention J The purpose of the present invention is to provide a novel photoconductive material, to provide an electrophotographic photoreceptor having practical high sensitivity characteristics and stable potential characteristics during repeated use; An object of the present invention is to provide an electrophotographic apparatus and a facsimile equipped with the electrophotographic photoreceptor.

[Means for Solving the Problems, Effects J] The present invention is an electrophotographic photoreceptor having a photosensitive layer on a conductive support, characterized in that the photosensitive layer contains a disazo pigment shown in the following - Funazo (1). It consists of an electrophotographic photoreceptor.

−Ship storage represents a coupler residue having a phenolic hydroxyl group.

In the general formula, X represents a residue necessary to form a polycyclic aromatic ring or a heterocycle by condensing with a benzene ring, Z represents an oxygen atom or a sulfur atom, and R1 and R2 represent a hydrogen atom, a substituted It represents an alkyl group, a carbocyclic aromatic group, or a heterocyclic aromatic group which may have a group, and R3 and R3 may form a ring together with a nitrogen atom.

Specifically, as Y in Funagura (1), in the formula, Y
represents an atomic group necessary for condensing with a pyrazine ring to form an aromatic hydrocarbon ring or a heterocycle;
is represented by the following - Funazura (2), where R3 is the same or different and is a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an alkoxy group, an aryl group, a cyan group, a substituted It represents an amino group, a carboxyl group or an ester thereof, and n represents an integer of 1 to 4.

- Specific examples of X in Funazura (2) include residues necessary to form a ring such as a naphthalene ring, anthracene ring, carbazole ring, benzcarbazole ring, and dibenzofuran ring, and as an alkyl group in R1 and R2. represents groups such as methyl, ethyl, and propyl; specific examples of aryl groups include phenyl, naphthyl, and anthryl; examples of aralkyl groups include benzyl and phenethyl; and heterocyclic groups include pyridyl, thienyl, carbazolyl, benzimidazolyl, groups such as benzothiazolyl,
Cyclic amino groups containing a nitrogen atom in the ring include pyrrole,
Examples include viroline, pyrrolidine, pyrrolidone, indole, indoline, carbazole, imidazole, pyrazole, pyrazoline, oxazine, phenoxazine, etc. Substituents include halogen atoms such as fluorine, chlorine, iodine, and bromine, methyl, ethyl, propyl, etc. Examples include alkyl groups such as methoxy and ethoxy, alkylamino groups such as dimethylamino and diethylamino, phenylcarbamoyl groups, nitro groups, cyan groups, and halomethyl groups such as trifluoromethyl.

The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer comprises at least two layers: a charge generation layer containing a disazo pigment represented by general formula (1) and a charge transport layer.

In addition, in the case of - ship stock (1), pigments in which X is a coupler residue condensed with a benzene ring to form a benzcarbazole ring are semiconductors because their absorption range extends to near the near-infrared region. It is also suitable as a charge generating material for lasers.

Further, the present invention comprises an electrophotographic apparatus equipped with the electrophotographic photoreceptor of the present invention.

Further, the present invention comprises an electrophotographic apparatus equipped with the electrophotographic photoreceptor of the present invention, and a facsimile machine having a receiving means for receiving image information from a remote terminal.

Typical specific examples of the disazo pigment represented by the general formula (1) of the present invention are listed below, but the disazo pigment used in the present invention is not limited to these.

The specific structure of the exemplified pigment will be expressed by describing only the parts that change in the basic form.

Basic type 1 Exemplary pigment (4) Exemplary pigment (5) Exemplary pigment (1) Exemplary pigment (6) Exemplary pigment (2) Exemplary pigment (7) Exemplary pigment (8) Exemplary pigment (3) Exemplary pigment (9) Exemplary pigment (10) Exemplary pigment (l　1) Exemplary pigment (12) Exemplary pigment (l　3) Exemplary pigment (19) Exemplary pigment (20) Exemplary pigment (21) Exemplary pigment (22) Exemplary pigment (23) Exemplary pigment (14) Exemplary pigment (15) Exemplary pigment Exemplary pigment (17) Exemplary pigment (18) Exemplary pigment (24) Exemplary pigment (25) Exemplary pigment (26) Exemplary pigment (27) Exemplary pigment (28) Exemplary pigment (29) Exemplary pigment (30) Exemplary pigment (31) Exemplary pigment (32) Exemplary pigment (36) Exemplary pigment (37) Exemplary pigment (38) Exemplary pigment (39) Exemplary pigment (40) Exemplary pigment (33) Exemplary pigment (34) Exemplary pigment (35) Basic type 2 Exemplary pigment rρ Exemplary pigment (42) C flood Exemplary pigment (43) Exemplary pigment (44) Exemplary pigment (45) p Exemplary pigment (46) Exemplary pigment (47) Exemplary pigment (48) Example work fee (49) Exemplary pigment (50) Exemplary pigment (55) Basic type 3 Exemplary pigment (56) R4: R6: H I Exemplary pigment (57) R4: H3 R5: H Exemplary face! 4 (5 Exemplary pigment (52) Q Exemplary pigment (53) Exemplary pigment (54) Exemplary pigment (58) :　　　-OCH.

R.

Knee ■ Exemplary pigment (59) :　　　　-CN R.

Knee H Exemplary pigment (60) ・Be◇ R5: Exemplary pigment (6 Knee ■ R.

Knee H I Exemplary pigment (62) R4 Knee H R5: Exemplary pigment (63) R4: ■ R5: Exemplary pigment (67) R4: CHs R6ni -CI(.

death! Exemplary pigment (68) R4: H R.

Knee H Exemplary pigment (64) R4: H 2-H Exemplary pigment (65) R4ni -coocna Knee H Exemplary pigment (66) Exemplary pigment (69) R4: H R.

Knee H Exemplary Pigment (70) R4: I2 Knee H The disazo pigment shown by grain formula (1) can be obtained by tetrazotizing the corresponding diamine by a conventional method and coupling it with a coupler in an aqueous system in the presence of an alkali, or by adding a tetrazonium salt to the disazo pigment. After converting to borofluoride salt or zinc chloride double salt, it is coupled with a coupler in an organic solvent such as N,N-dimethylformamide or dimethyl sulfoxide in the presence of a base such as sodium acetate, triethylamine, or N-methylmorpholine. It can be easily synthesized by

- When synthesizing a disazo pigment in which A + and A 2 in shipyard (1) are different couplers, first 1 mol of one coupler is coupled to 1 mol of the above-mentioned tetrazonium salt, and then the other is coupled. Alternatively, one amine group of the diamine is protected with an acetyl group, etc., this is diazotized, one coupler is coupled, and the protecting group is removed with hydrochloric acid etc. It can be synthesized by hydrolyzing it, diazotizing it again, and coupling it with the other coupler.

Synthesis example (synthesis of exemplified pigment (1)) In a 300mJ2 beaker, 150rr+j2 of water, 22 ml of concentrated hydrochloric acid
Add 0 ml2 (0.23 mol) and (0,032 mol) and cool to 0°C, and add a solution of 4.6 g (0,067 mol) of sodium nitrite dissolved in 10 mβ of water while maintaining the liquid temperature at 5°C. It was added dropwise over 1 minute. 1
After stirring for 5 minutes, carbon filtration was performed, and in this solution, 10.5 g (0,096 mol) of sodium fluoride was added to 90 ml of water.
The solution was stirred at m°C, and the precipitated borofluoride salt was collected by filtration, washed with cold water and then acetonitrile, and dried under reduced pressure at room temperature.

Yield 18.0g, yield 91% Next 112 Heater i, m D MF 500
After adding m 12 and dissolving it and cooling the liquid temperature to 5℃,
10.2 g (0,020 mol) of the borofluoride salt obtained earlier
and then 5.1 g of triethylamine (0,0
50 mol) was added dropwise over 5 minutes. After stirring for 2 hours, the precipitated pigment was collected by filtration, washed four times with DMF and three times with water, and then freeze-dried.

Yield: 16.1 g, yield: 85% The electrophotographic photoreceptor of the present invention has the general formula (
It has a photosensitive layer containing the disazo pigment shown in 1). The form of the photosensitive layer may be any known form, but - a photosensitive layer containing a disazo pigment shown in Funazou (1) is used as a charge generation layer, and a charge transport layer containing a charge transport substance therein; Particularly preferred is a functionally separated type photosensitive layer in which the following layers are laminated.

The charge generation layer can be formed by coating a coating solution prepared by dispersing the above-mentioned azo material together with a binder resin in a suitable solvent on a conductive support by a known method, and the film thickness thereof is, for example, 5 μm. Below, preferably 0.1
A thin film layer of ~lum is desirable.

The binder resin used in this case is selected from a wide range of insulating resins or organic photoconductive polymers, including polyvinyl butyral, polyvinylbenzal, polyarylate, polycarbonate, polyester, phenoxy resin, cellulose resin, acrylic resin, polyurethane. etc., and the amount used is 8% in terms of content in the charge generation layer.
It is 0% by weight or less, preferably 40% by weight or less.

The solvent used is preferably selected from those that dissolve the resin described above but do not dissolve the charge transport layer or undercoat layer described below.

Specifically, ethers such as tetrahydrofuran and 1',4-dioxane, ketones such as cyclohexanone and methyl ethyl ketone, amides such as N,N-dimethylformamide, esters such as methyl acetate and ethyl acetate, toluene, and xylene. , aromatics such as chlorobenzene, alcohols such as metazole, ethanol, and 2-propanol, and aliphatic halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, and trichlorethylene.

The charge transport layer is laminated above or below the charge generation layer, and has the function of receiving charge carriers from the charge generation layer in the presence of an electric field and transporting them.

The charge transport layer is formed by dissolving a charge transport substance in a solvent together with an appropriate binder resin as necessary and coating the layer, and the film thickness is generally 5 to 40 μm, but 1
5 to 30 μm is preferable.

Charge transport substances include electron transport substances and hole transport substances. Examples of electron transport substances include 2゜4,7-trinitrofluorenone, 2,4,5゜7-titranitrofluorenone, chloranil, and tetranitrofluorenone. Examples include electron-withdrawing substances such as cyanoquinodimethane, and polymerization of these electron-withdrawing substances.

Hole axis transporting substances include polycyclic aromatic compounds such as pyrene and anthracene, carbazole series, indole series, imidazole series, oxazole series, thiazole series, oxadiazole series, pyrazole series, pyrazoline series, thiadiazole series, and triazole series. Complex compounds such as compounds, p-
Hydrazone-based compounds such as diethylaminobenzaldehyde-N,N-diphenylhydrazone, N,N-diphenylhydrazino-3-methylidene-9-ethylcarbazole, a-phenyl-4°-N,N-diphenylaminostilbene, 5-[ Mainly containing styryl compounds such as 4-(di-p-tolylamino)benzylidene]-5H-dibenzo[a,d]cycloheptene, benzidine compounds, triarylmethane compounds, triphenylamine, or groups consisting of these compounds. Examples thereof include bombers (for example, poly-N-vinylcarbazole, polyvinylanthracene, etc.) having in the chain or side chain.

In addition to these organic charge transport materials, inorganic materials such as selenium, selenium-tellurium, amorphous silicon, and cadmium sulfide can also be used.

Further, these charge transport materials can be used alone or in combination of two or more.

When the charge transport material does not have film-forming properties, a suitable binder can be used. Specifically, insulating resins such as acrylic resin, polyarylate, polyester, polycarbonate, polystyrene, acrylonitrile-styrene copolymer, polyacrylamide, polyamide, and chlorinated rubber, or organic photoconductive resins such as poly-N-vinylcarbazole and polyvinylanthracene. Polymers and the like can be mentioned.

Examples of the conductive support on which the photosensitive layer is formed include aluminum, aluminum alloy, copper, zinc stainless steel, vanadium, molybdenum, chromium titanium, nickel, indium, gold, and platinum. In addition, plastics (e.g., polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, etc.) or conductive particles (e.g., carbon black, silver particles, etc.) are coated with these metals or alloys using a suitable binder. A support in which a plastic or metal substrate is coated with a resin, or a support in which plastic or paper is impregnated with conductive particles can be used.

An undercoat layer having barrier and adhesive functions can also be provided between the conductive support and the photosensitive layer.

The undercoat layer can be formed of casein, polyvinyl alcohol, nitrocellulose, polyamide (nylon 6, nylon 66, nylon 610, copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, aluminum oxide, or the like.

The thickness of the undercoat layer is 5 μm or less, preferably 0°1 to 3 μm.
m is appropriate.

Another specific example of the present invention is an electrophotographic photoreceptor containing the above-mentioned disazo pigment and charge transport material in the same layer. At this time, poly-N-
Charge transfer complexes consisting of vinyl carbazole and trinitrofluorenone can also be used.

The electrophotographic photoreceptor of this example can be formed by coating and drying a solution in which the above-mentioned disazo pigment and charge transfer complex are dispersed in a suitable resin solution.

The pigment used in each electrophotographic photoreceptor is 189
The crystal form of the disazo pigment represented by formula (1) may be amorphous or crystalline, and if necessary, the crystal form of the disazo pigment represented by formula (1) may be amorphous or crystalline.
) It is also possible to use a combination of two or more types of disazo pigments, or to use them in combination with a known charge-generating substance.

The electrophotographic photoreceptor of the present invention can be used not only for electrophotographic copying machines, but also for laser beam printers, CRT printers, LED printers, liquid crystal printers, laser plate making,
It can also be widely used in electrophotographic applications such as facsimile printers.

Next, an electrophotographic apparatus and a facsimile equipped with the electrophotographic photoreceptor of the present invention will be described.

FIG. 1 shows a schematic configuration of a general transfer type electrophotographic apparatus using the drum type photoreceptor of the present invention.

In the figure, reference numeral 1 denotes a drum-type photoreceptor as an image carrier, which is rotated at a predetermined circumferential speed in the direction of the arrow around an axis 1a. During the rotation process, the photoreceptor 1 is uniformly charged on its peripheral surface to a predetermined positive or negative potential by the charging means 2, and then subjected to photoimage exposure 1.
(slit exposure, laser beam scanning exposure, etc.).

As a result, electrostatic latent images corresponding to the exposed images are sequentially formed on the circumferential surface of the photoreceptor.

The electrostatic latent image is then developed with toner by the developing means 4,
The toner developed image is sequentially transferred by the transfer means 5 onto the surface of the transfer material P, which is fed from a paper feeding section (not shown) between the photoreceptor 1 and the transfer means 5 in synchronization with the rotation of the photoreceptor 1. To go.

The transfer material P that has undergone the image transfer is separated from the photoreceptor surface and introduced into the image fixing means 8, where the image is fixed and a copy is produced.
will be printed out on the outside of the aircraft.

After the image has been transferred, the surface of the photoreceptor 1 is cleaned by a cleaning means 6 to remove residual toner, and subjected to a charge removal process by a pre-exposure means 7, and is repeatedly used for image formation.

As the uniform charging means 2 for the photoreceptor 1, a corona charging device is generally widely used.

Further, as for the transfer device 5, a corona transfer means is generally widely used.

An electrophotographic apparatus is constructed by combining a plurality of components such as the photoreceptor and developing means cleaning means described above into an apparatus unit, and this unit is configured to be detachable from the apparatus main body. Good too. For example, the photoreceptor 1 and the cleaning means 6 may be integrated into one device unit, and configured to be detachable using a guide means such as a rail on the main body of the device. At this time, the above-mentioned device unit may include a charging means and/or a developing means.

In addition, when an electrophotographic device is used as a copying machine or a printer, light image exposure involves scanning the reflected light or transmitted light from the document, or by reading the document and converting it into a signal. driving the array,
Alternatively, it is performed by driving a liquid crystal shutter array.

Furthermore, when used as a facsimile printer, the optical image exposure is exposure for printing received data.

FIG. 2 is a block diagram showing an example of this case.

The controller 11 controls the image reading section 10 and the printer 19.

The entire controller 11 is controlled by a CPU 17.

The read data from the image reading unit is transmitted to the partner station through the transmitting circuit 13. Data received from the partner station is sent to the printer 19 through the receiving circuit 12. Predetermined image data is stored in the image memory. A printer controller 18 controls a printer 19. 14
is a telephone.

The image received from the circuit MA 15 (image information from a remote terminal connected via the line) is demodulated by the reception circuit 12, and then the CPU 17 performs signal processing on the image information and sequentially stores it in the image memory 16. Ru. When at least one page of images is stored in the memory 16, the image of that page is stored. The CPU 17 uses 1 from the memory 16.
Printer controller 18 reads page image information
1 page of image information signaled to is sent out.

When the printer controller 18 receives one page of image information from the CPtJ 17, it controls the printer 19 to record the image information of that page.

Note that the CPU 17 receives the next page while the printer 19 is recording.

As described above, images are received and recorded.

[Example] Examples 1 to 22 5 g of methoxymethylated nylon (weight average molecular weight 32,000) and 10 g of alcohol-soluble copolymerized nylon (weight average molecular weight 29,000) were placed on an aluminum substrate in 95 g of methanol.
A solution dissolved in was applied with a Mayer bar to form an undercoat layer having a thickness of 1 μm after drying.

Next, 5 g of Exemplified Pigment (1) was added to a solution containing 90 g of cyclohexanone and 2 g of butyral resin (degree of butyralization: 63 mol %), and dispersed in a sand mill for 20 hours. This dispersion was applied onto the previously formed undercoat layer using a Mayer bar so that the film thickness after drying was 0.3 μm, and dried to form a charge generation layer.

Next, 5 g of a hydrazone compound represented by the structural formula below and 5 g of polymethyl methacrylate resin (number average molecular weight 100,000) were dissolved in 40 g of chlorobenzene, and this was placed on the charge generation layer so that the film thickness after drying was 21 Lim. The electrophotographic photoreceptor of Example 1 was prepared by coating with a Mayer bar and drying to form a charge transport layer.

Example 2 using other exemplary pigments in place of exemplary pigment (1)
Electrophotographic photoreceptors corresponding to Examples 1 to 22 were prepared in exactly the same manner.

The prepared electrophotographic photoreceptor was negatively charged with a corona discharge of 15 KV using an electrostatic copying paper tester Model 5P-428 manufactured by Kawaguchi Denki ■, held in a dark place for 1 second, and then charged with a halogen lamp. Immediate exposure was performed at 10 lux to evaluate charging characteristics.

As for charging characteristics, surface potential ■. The exposure amount El/2 required for the surface potential to attenuate to 172 after being left in a dark place was measured.

Show the results.

19 (66) 700 1. 3
820 (68) 700 1.6
221 (69) 700 1.2
922 (70) 700 1.6
2 Comparative Examples 1 and 2 Electrophotographic photoreceptors were prepared in exactly the same manner as in Example 1, except that the azo pigment used in Example 1 was replaced with comparative pigments (A) and (B) shown by the following structural formulas. , charging characteristics were similarly evaluated. Show the results.

Comparative pigment (A) Comparative pigment (B) and the amount of variation in bright area potential (ΔVL) was measured.

Example 2.3.4.5.6.7.8.9.1112.1
The electrophotographic photoreceptors prepared in Examples 3 and 17 were also evaluated in the same manner. Show the results.

Note that a negative sign in the amount of potential fluctuation represents a decrease in the absolute value of the potential, and a positive sign represents an increase in the absolute value of the potential.

1 (A) 700 8.392
(B) 690 2.79 From this result, it can be seen that the electrophotographic photoreceptor of the present invention has sufficient charging ability and excellent sensitivity.

Examples 23 to 35 The electrophotographic photoreceptor prepared in Example 1 was used in an electrophotographic copying machine equipped with a -6.5 KV corona charger, an exposure optical system, a developer, a transfer charger, a static elimination exposure optical system, and a cleaner. Attached to the cylinder.

Initial dark potential■. and bright area potential■, respectively -700
Variation in dark potential M (△Vo) 32 when V is set at around -200V and used repeatedly 5,000 times.
+5 +5 +5 +5 +10 +5 Comparative Examples 3 and 4 The electrophotographic photoreceptors prepared in Comparative Example 1.2 were repeatedly used in the same manner as in Example 23, and the amount of potential fluctuation was measured. Show the results.

3 -50 +80 4 -80 +100 From the above results, it can be seen that the electrophotographic photoreceptor of the present invention has little potential fluctuation during repeated use.

Example 36 A subbing layer of polyvinyl alcohol having a thickness of 05 μm was formed on the aluminum surface of an aluminum vapor-deposited polyethylene terephthalate film. On top of this, the dispersion of the disazo pigment used in Example 2 was applied with a Mayer bar and dried, resulting in a film thickness of 0.2μ.
A charge generation layer of m was formed.

A solution prepared by dissolving 5 g of a styryl compound with the following structural formula and 5 g of polycarbonate resin (weight average molecular weight 55,000) in 40 g of tetrahydrofuran was applied onto the charge generation layer and dried to form a charge transport layer with a thickness of 17 μm. did.

The charging characteristics and durability characteristics of the produced electrophotographic photoreceptor were measured in the same manner as in Examples 1 and 23. Show the results.

Vo Knee 695V El/2:1.52Rux-sec △Vo:QV △V,:OV Example 37 Electrophotographic photoreceptor prepared in Example 2 with the charge generation layer and charge transport layer applied in the reverse order Create a photoreceptor,
The charging characteristics were evaluated in the same manner as in Example 1. However, the charging was positive.

Vo: +700V El/2 +4.32j2ux-sec Example 38 On the charge generation layer prepared in Example 2, 5 g of 2.4.7-dolinitro-9-fluorenone and poly-44°-2,2-
A solution obtained by dissolving 5 g of propane carbonate (molecular weight: 300,000) in 50 g of tetrahydrofuran was applied and dried using a Mayer bar to form a charge transport layer having a thickness of 18 LLm.

The charging characteristics of the produced electrophotographic photoreceptor were evaluated in the same manner as in Example 1. However, the charging was positive.

V,: +680V El/2: 4.92j2ux-sec Example 39 0.5g of exemplified pigment (2) and 9.5g of cyclohexanone
It was also dispersed in a paint shaker for 5 hours. A solution prepared by dissolving 5 g of the charge transport material used in Example 1 and 5 g of the polycarbonate resin in 40 g of tetrahydrofuran was added thereto, and the mixture was further shaken for 1 hour. The coating liquid thus prepared was applied onto an aluminum substrate using a Mayer bar and dried to a film thickness of 16 μm.
A photosensitive layer of m was formed.

The charging characteristics of the produced electrophotographic photoreceptor were evaluated in the same manner as in Example 1. The charging was positive.

VQ: +680V El/2: 6.81ffux-sec [Effect 1 of the Invention The electrophotographic photoreceptor of the present invention uses a disazo instant powder with a specific structure in the photosensitive layer, thereby improving the efficiency of generating charge carriers inside the photosensitive layer. It has the remarkable effect of improving one or both of the injection efficiency and providing excellent sensitivity and potential stability during repeated use. be effective.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a general transfer type electrophotographic apparatus. Symbol 1 is a drum-type photoreceptor (electrophotographic photoreceptor of the present invention) as an image carrier, 2 is a corona charging device, 3 is an exposure section, 4
9. 5 is a transfer means, 6 is a cleaning means,
7 is a pre-exposure means, 8 is an image fixing means, L is a light image exposure, and P is a transfer material subjected to image transfer. FIG. 2 is a block diagram of a facsimile machine using an electrophotographic device as a printer. 10 is an image reading unit, 11 is a controller 12 is a receiving circuit, 13 is a transmitting circuit, 14 is a telephone 15 is a line, 16
17 is an image memory, CPU 18 is a printer controller, and 19 is a printer. Fig. 1 Schematic configuration of a general transfer type electrophotographic device using the electrophotographic photoreceptor of the present invention

Claims (1)

[Scope of Claims] 1. An electrophotographic photoreceptor having a photosensitive layer on a conductive support, wherein the photosensitive layer contains a disazo pigment represented by the general formula (1). General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼(1) In the formula, Y represents an atomic group necessary to condense with the pyrazine ring and form an aromatic hydrocarbon ring or a heterocycle, and A_1
and A_2 represents a coupler residue having a phenolic hydroxyl group represented by the following general formula (2). General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (2) In the formula, X represents a residue necessary to form a polycyclic aromatic ring or a heterocycle by condensing with a benzene ring, and Z represents an oxygen atom or R_1 and R_2 represent a sulfur atom, R_1 and R_2 represent a hydrogen atom, an alkyl group that may have a substituent, a carbocyclic aromatic group, or a heterocyclic aromatic group;
2 may form a ring together with the nitrogen atom. 2. The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer comprises at least two layers: a charge generation layer containing a disazo pigment represented by general formula (1) and a charge transport layer. 3. An electrophotographic apparatus comprising the electrophotographic photoreceptor according to claim 1. 4. A facsimile machine comprising an electrophotographic apparatus comprising the electrophotographic photoreceptor according to claim 1 and a receiving means for receiving image information from a remote terminal.