JPH04238361A - Electrophotographic sensitive body, electrophotographic device provided with the same and facsimile equipment - Google Patents

Abstract

PURPOSE:To obtain satisfactory high sensitivity characteristics and stable potential characteristics at the time of repeated utilization by providing a photosensitive layer contg. a specified disazo pigment on an electrically conductive base material. CONSTITUTION:A photosensitive layer contg. a disazo pigment represented by formula I is provided on an electrically conductive base material. In the formula I, each of R1 and R2 is H, halogen such ass Cl atom or Br atom, alkyl group such AS methyl group or ethyl group or aryl group which may have a substituent such as phenyl group, each of A1 and A2 is a residual group of a coupler having a phenolic hydroxyl group and A1 and A2 may be different from each other. The photosensitive layer is preferably composed of at least two layers, that is, an electric charge generating layer contg. the disazo pigment represented by the formula I and a electric charge transferring layer.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor containing an azo pigment having a specific structure in a photosensitive layer, an electrophotographic apparatus equipped with the electrophotographic photoreceptor, and a facsimile.

0002

2. Description of the Related Art Conventionally, inorganic photoconductive materials 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- Oxadiazo
There are known methods that use low-molecular organic photoconductive substances such as fluorophores, and also those that combine such organic photoconductive substances with various dyes and pigments. 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. Particularly recently, a functionally separated photoreceptor has been developed 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. As a result, significant improvements have been made in the sensitivity and durability, which were considered to be shortcomings of conventional organic electrophotographic photoreceptors.

[0003]Azo pigments exhibit excellent photoconductivity, and because compounds with various properties can be easily obtained by combining the azo component and coupler component, many compounds have been proposed to date. For example, JP-A-60-
No. 131539, Japanese Patent Application Laid-Open No. 57-47357,
It is described in Japanese Patent Application Laid-Open No. 54-22834. However, electrophotographic photoreceptors using conventional azo pigments have not always been sufficient in terms of sensitivity and potential stability during repeated use.

0004

SUMMARY OF THE INVENTION The objects of the present invention are to provide a novel photoconductive material, an electrophotographic photoreceptor having good 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.

[0005]

[Means for Solving the Problems] The present invention comprises an electrophotographic photoreceptor characterized in that it has a photosensitive layer containing an azo pigment represented by the following general formula (1) on a conductive support. General formula (1) In the formula, R1 and R2 are the same or different and are hydrogen atoms,
It represents a halogen atom, an alkyl group, or an aryl group which may have a substituent, and A1 and A2 are the same or different and represent a coupler residue having a phenolic hydroxyl group. Specifically, halogen atoms include chlorine atoms and bromine atoms, and alkyl groups include methyl, ethyl, and aryl groups.
Examples of the group include phenyl and the like, and examples of the substituent include alkyl groups such as ethyl, and halogen atoms such as chlorine and bromine atoms.

Preferred examples of the coupler residues having a phenolic hydroxyl group represented by A2 and A2 include residues represented by the following general formulas (2) to (6).

General formula (2)

General formula (3)

General formula (4)

General formula (5)

General formula (6)

X in general formulas (2), (3) and (4)
represents a residue necessary to form a polycyclic aromatic ring or heterocycle such as a naphthalene ring, anthracene ring, carbazole ring, benzcarbazole ring, dibenzofuran ring, etc. which may have a substituent by condensation with a benzene ring, Y in general formula (6) represents a divalent aromatic hydrocarbon group which may have a substituent or a divalent heterocyclic group containing a nitrogen atom in the ring, specifically o-phenylene, o-naphthylene, perinaphthylene, 1,2-antrylene, 3,4-pyrazorudiyl, 2,3-pyridinediyl, 4,5-pyridinediyl,
Divalent groups such as 6,7-indazolediyl and 6,7-quinolinediyl are mentioned, and those of general formulas (2) and (3)
R3 and R4 in the formula represent a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group which may have a substituent, and R3 and R4 are both bonded via a nitrogen atom to form a cyclic amino group. R5 in the general formula (4) represents a hydrogen atom, an alkyl group that may have a substituent, an aryl group, an aralkyl group, or a heterocyclic group, and the general formula (5) R6 represents a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group which may have a substituent, and the alkyl group in the above expression includes groups such as methyl, ethyl, propyl, and an aryl group. Specific examples include groups such as phenyl, naphthyl, and anthryl; aralkyl groups include benzyl and phenethyl; heterocyclic groups include pyridyl, thienyl, carbazolyl, benzimidazolyl, and benzothiazolyl; and groups containing a nitrogen atom in the ring. Cyclic amino groups include pyrrole, pyrroline, pyrrolidine,
pyrrolidone, indole, indoline, carbazole,
imidazole, pyrazole, pyrazoline, oxazine,
Examples include phenoxazine. Substituents include halogen atoms such as fluorine, chlorine, iodine, and bromine, alkyl groups such as methyl, ethyl, and propyl, methoxy,
Examples include alkoxy groups such as ethoxy, alkylamino groups such as dimethylamino and diethylamino, phenylcarbamoyl groups, nitro groups, cyano groups, and halomethyl groups such as trifluoromethyl. Z in general formula (2) is an oxygen atom or It represents a sulfur atom, and n is an integer of 0 or 1.

In addition, A1 and A2 in general formula (1) are general formula (2), (3) or (4), and X in the formula is fused with a benzene ring to form a benzcarbazole ring. Pigments using such couplers have an absorption range extending to near the near-infrared region, and are therefore suitable as charge-generating materials for semiconductor lasers.

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

The present invention also comprises an electrophotographic apparatus equipped with the electrophotographic photoreceptor of the present invention.

The present invention also 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.

Next, typical examples of the azo pigment represented by the general formula (1) of the present invention are listed in Tables 1-1 to 1-10.
The azo pigments used in the present invention are 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 A1-N=N-M-N
=N-A2

Table 1-1 Table 1-2 Table 1-3 Table 1-4 Table 1-5 Table 1-6 Table 1-7 Table 1-8 Table 1-9 Table 1-10

The azo pigment represented by the general 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 converting a tetrazonium salt into a borofluoride salt or a zinc chloride double salt. After converting to
Sodium acetate, triethylamine, N, in an organic solvent such as N,N-dimethylformamide or dimethyl sulfoxide
- It can be easily synthesized by coupling with a coupler in the presence of a base such as methylmorpholine.

When synthesizing an azo pigment in which A1 and A2 in the general formula (1) are different couplers, one coupler is first added to 1 mole of the above-mentioned tetrazonium salt.
Coupling one mole and then the other coupler
Synthesize by coupling 1 mole of diamine, or protect one amino group of the diamine with an acetyl group, diazotize it, couple one coupler, and then hydrate the protecting group with hydrochloric acid etc. It can be synthesized by decomposing it, diazotizing it again, and coupling the other coupler.

Synthesis Example (Synthesis of Pigment 1) 150 ml of water in a 300 ml beaker,
20ml (0.23mol) of concentrated hydrochloric acid and 14.0
g (0.032 mol) and stirred at 5°C for 30 minutes, then cooled to 0°C, and a solution of 4.6 g (0.067 mol) of sodium nitrite dissolved in 10 ml of water was heated to a temperature of 2. The mixture was added dropwise over 10 minutes while keeping the temperature below ℃. After stirring for 15 minutes, carbon filtration was performed, and 10% of sodium fluoroborate was added to the solution.
．． A solution obtained by dissolving 5 g (0.096 mol) in 90 ml of water was added dropwise under stirring, and the precipitated borofluoride salt was collected by filtration, washed with cold water, then acetonitrile, and dried under reduced pressure at room temperature. Yield 13.2g, yield 65%

Next, put 500 ml of DMF into a 1 liter beaker, and add 11.1 g (0.0 g) of Naphthol AS.
After dissolving 042 mol) and cooling the liquid temperature to 5°C, 12.7 g (0.020 mol) of the previously obtained borofluoride salt was dissolved, followed by 5.1 g (0.050 mol) of triethylamine.
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 13.6g, yield 67%

Elemental analysis value C Calculated value 70.72%, Actual value 70.68%H
Calculated value 4.09%, actual value 4.09%N Calculated value 17
．． 06%, actual value 17.08%

The electrophotographic photoreceptor of the present invention has a photosensitive layer containing an azo pigment represented by the general formula (1) on a conductive support. The form of the photosensitive layer may be any known form, but it is preferable that the photosensitive layer containing the azo pigment represented by the general formula (1) is used as a charge generation layer, and a charge transport layer containing a charge transport substance is added thereto. Laminated functionally separated photosensitive layers are particularly preferred.

The charge generation layer can be formed by coating a coating solution in which the azo pigment described above is dispersed together with a binder resin in a suitable solvent on a conductive support by a known method, and the film is It is desirable that the thin film layer has a thickness of, for example, 5 μm or less, preferably 0.1 to 1 μm. The binder resin used in this case is selected from a wide range of insulating resins or organic photoconductive polymers, including polyvinyl butyral, polyvinyl benzal, polyarylate, polycarbonate, polyester, phenoxy resin, cellulose resin, and acrylic resin. , polyurethane, etc. are preferred, 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, Examples include aromatics such as xylene and chlorobenzene, alcohols such as methanol, ethanol, and 2-propanol, and aliphatic halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, and trichloroethylene.

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 15 to 30 μm.
is preferred.

Charge transporting substances include electron transporting substances and hole transporting substances, and examples of electron transporting substances include 2 and 4
Examples include electron-withdrawing substances such as , 7-trinitrofluorenone, 2,4,5,7-tetranitrofluorenone, chloranil, and tetracyanoquinodimethane, and polymerized versions of these electron-withdrawing substances. Hole-transporting substances include polycyclic aromatic compounds such as pyrene and anthracene, carbazole-based, indole-based, imidazole-based, oxazole-based, thiazole-based, oxadiazole-based, and pyrazole-based substances. , heterocyclic compounds such as pyrazoline, thiadiazole, and triazole compounds, p-diethylaminobenzaldehyde N,N-diphenylhydrazone,
N,N-diphenylhydrazino-3-methylidene-9-
Hydrazone compounds such as ethylcarbazole, α-phenyl-4'-N,N-diphenylaminostilbene,
5-[4-(di-p-tolylamino)benzylidene]-
A styryl compound such as 5H-dibenzo[a,d]cycloheptene, a benzidine compound, a triarylmethane compound, triphenylamine, or a polymer having a group consisting of these compounds in its main chain or side chain (for example, poly- N-vinylcarbazole, polyvinylanthracene, etc.). In addition to these organic charge transport materials, selenium, selenium-tellurium, amorphous silicon,
Inorganic materials such as 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, acrylic resin, polyarylate, polyester, polycarbonate, polystyrene, acrylonitrile-styrene copolymer, polyacrylamide,
Examples include insulating resins such as polyamide and chlorinated rubber, and organic photoconductive polymers such as polyN-vinylcarbazole and polyvinylanthracene.

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 are used. In addition, plastics (e.g., polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, etc.) or conductive particles (e.g., carbon black, silver particles, etc.) coated with these metals or alloys by vacuum deposition are coated with a suitable binder resin. In addition, a support coated on a plastic or metal substrate, or a support made of plastic or paper impregnated with conductive particles can be used.

An undercoat layer having barrier and adhesive functions may 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 suitably 5 μm or less, preferably 0.1 to 3 μm.

Another specific example of the present invention is an electrophotographic photoreceptor containing the above-mentioned azo pigment and charge transport material in the same layer. In this case, a charge transfer complex consisting of poly N-vinylcarbazole and trinitrofluorenone can also be used as the charge transport substance. The electrophotographic photoreceptor of this example can be formed by coating and drying a solution in which the azo pigment and charge transfer complex described above are dispersed in a suitable resin solution. The pigment used in any electrophotographic photoreceptor is an azo pigment represented by the general formula (1), and the crystal form thereof may be amorphous or crystalline. It is also possible to use a combination of two or more types of azo pigments shown or 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, C
RT printer, LED printer, LCD printer,
It can also be widely used in electrophotographic applications such as laser engraving and facsimile.

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

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, 1 is a drum-type photoreceptor as an image carrier, and a shaft 1
It is rotated at a predetermined circumferential speed in the direction of the arrow around point a. During the rotation process, the photoreceptor 1 is uniformly charged to a predetermined positive or negative potential on its circumferential surface by the charging means 2, and then subjected to light image exposure L (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 a developing means 4, and the toner-developed image is transferred by a transfer means 5 from a paper feed section (not shown) between the photoreceptor 1 and the transfer means 5, when the photoreceptor 1 is rotated. The images are sequentially transferred onto the surface of the transfer material P that is fed in synchronization with the image data. 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 printed out outside the machine as a copy. After the image has been transferred, the surface of the photoreceptor 1 is cleaned by a cleaning means 6 to remove residual toner after transfer, and is subjected to a charge removal process by a pre-exposure means 7 and used repeatedly 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 above-mentioned photoreceptor, developing means, and cleaning means into an apparatus unit, and this unit is detachably attached to the main body of the apparatus. It may be configured. For example, the photoreceptor 1 and the cleaning means 6 may be integrated into one apparatus unit, and may be configured to be detachable using a guide means such as a rail on the main body of the apparatus. At this time, the above-mentioned device unit may include a charging means and/or a developing means. In addition, when the electrophotographic apparatus is used as a copying machine or a printer, the light image exposure L is the reflected light or transmitted light from the original, or the original is read and converted into a signal, and this signal is used to generate a laser beam. This is performed by scanning a screen, driving a light emitting diode array, or driving a liquid crystal shutter array.

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

FIG. 2 is a block diagram showing an example of this case. A controller 11 controls an image reading section 10 and a printer 19. The entire controller 11 is controlled by a CPU 17. The read data from the image reading section is transmitted to the other party's 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. line 15
After the image received from the remote terminal (image information from a remote terminal connected via a line) is demodulated by the receiving circuit 12, the CPU 17 performs signal processing on the image information and sequentially stores it in the image memory 16. . When at least one page of images is stored in the memory 16, the image of that page is stored. The CPU 17 reads one page of image information from the memory 16 and sends out the one page of image information signaled to the printer controller 18. printer control
When the printer 18 receives one page of image information from the CPU 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.

[0037]

[Example] Examples 1 to 8 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 support in methanol. 95
A solution dissolved in 10 g was applied using a Mayer bar to form an undercoat layer having a thickness of 1 μm after drying. Next, 5 g of Pigment 1 was added to a solution prepared by dissolving 2 g of butyral resin (butyralization degree 63 mol %) in 95 g of cyclohexanone, 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 0.2 μm, and dried to form a charge generation layer.

Next, 5 g of a hydrazone compound shown by the following structural formula and polymethyl methacrylate (weight average molecular weight 10
Example 1: 5 g of chlorobenzene was dissolved in 40 g of chlorobenzene, and applied onto the charge generation layer using a Mayer bar so that the film thickness after drying was 20 μm, and dried to form a charge transport layer. An electrophotographic photoreceptor was prepared.

Electrophotographic photoreceptors corresponding to Examples 2 to 8 were prepared in exactly the same manner using other exemplary pigments in place of Pigment 1.

The produced electrophotographic photoreceptor was manufactured by Kawaguchi Electric Co., Ltd.
The paper was negatively charged with a -5KV corona discharge using an electrostatic copying paper tester Model SP-428 manufactured by Manufacturer Co., Ltd., held in a dark place for 1 second, and then exposed to light using a halogen lamp at an illuminance of 10 lux to evaluate the charging characteristics. did. As for charging characteristics, the surface potential V0 and the exposure amount E1/2 required for the surface potential to attenuate to 1/2 after being left in a dark place were measured. Show the results.

Example 1 Pigment 1 V0: -700V, E1/2: 4.
0 lux/second Example 2 Pigment 5 V0: -700V, E1/2: 2.
1 lux/second Example 3 Pigment 10 V0: -690V, E1/2: 4.6
Lux/Second Example 4 Pigment 16 V0: -685V, E1/2: 1.9
Lux/Second Example 5 Pigment 19 V0: -705V, E1/2: 2.4
Lux/Second Example 6 Pigment 26 V0: -720V, E1/2: 4.8
Lux/Second Example 7 Pigment 27 V0: -710V, E1/2: 2.4
Lux/Second Example 8 Pigment 29 V0: -705V, E1/2: 4.3
looks second

Comparative Example 1 An electrophotographic photoreceptor was prepared in exactly the same manner as in Example 1, except that the azo pigment used in Example 1 was replaced with Comparative Pigment 1, and the charging characteristics were evaluated in the same manner. Show the results. V0:-710V
, E1/2: 7.4 lux·sec From these results, it can be seen that the electrophotographic photoreceptor of the present invention has sufficient charging ability and excellent sensitivity.

Examples 9 to 12 The electrophotographic photoreceptors prepared in Examples 1, 2, 4, and 5 were charged with a -6.5 KV corona charger, exposure light: science, developer, transfer charger, and static elimination exposure. It was attached to the cylinder of an electrophotographic copying machine equipped with an optical system and a cleaner. The initial dark potential VD and light potential VL are -700V and -2, respectively.
The amount of variation ΔVD in the dark area potential and the amount of variation ΔVL in the bright area potential were measured when the battery was set at around 00V and used repeatedly 5,000 times. Show the results. Note that a negative sign in the amount of change in potential represents a decrease in the absolute value of the potential, and a positive sign represents an increase in the absolute value of the potential. Example 9 ΔVD: -20V, ΔVL: +3
0V Example 10 ΔVD: -10V, ΔVL: +
20V Example 11 ΔVD: +5V, ΔVL
: +25V Example 12 ΔVD: -10V, ΔV
L: +25V

Comparative Example 2 Regarding the electrophotographic photoreceptor prepared in Comparative Example 1, Example 9
Potential fluctuations during repeated use were measured using the same method as above. Show the results. ΔVD: -10V, ΔVL: +60V From the above results, it can be seen that the electrophotographic photoreceptor of the present invention has little potential fluctuation during repeated use.

Example 13 A subbing layer of polyvinyl alcohol having a thickness of 0.5 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 4 was applied with a Meyer bar and dried, resulting in a film thickness of 0.2
A charge generation layer of .mu.m was formed. Next, a solution prepared by dissolving 5 g of a styryl compound having the following structural formula and 5 g of polycarbonate (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 21 μm. was formed. The charging characteristics and durability characteristics of the produced electrophotographic photoreceptor were measured in the same manner as in Examples 1 and 9. Show the results. V0: -700V, E1/2: 1.6 lux seconds, Δ
VD: 0V, ΔVL: +15V

Example 14 An electrophotographic photoreceptor was prepared by applying the charge generation layer and charge transport layer of the electrophotographic photoreceptor prepared in Example 7 in the reverse order, and the charging characteristics were evaluated in the same manner as in Example 1. . However, the charging was positive. V0: +705V, E1/2: 3.9 lux/sec

0
Example 15 5 g of 2,4,7-trinitro-9-fluorenone and poly-4,4'-dioxydiphenyl-2,2-propane carbonate ( A solution obtained by dissolving 5 g of molecular weight 300,000 in 50 g of tetrahydrofuran was applied using a Mayer bar to form a charge transport layer having a thickness of 18 μm after drying. The charging characteristics of the produced electrophotographic photoreceptor were evaluated in the same manner as in Example 1. However, the charging was positive. V0: +710V, E1/2: 1.
8 lux seconds.

Example 16 0.5 g of Pigment 16 was dispersed with 9.5 g of cyclohexanone in a paint shaker for 5 hours. Example 1 here
5 g of the same charge transport material used in and polycarbonate 5
A solution prepared by dissolving 1.0 g of 1.0 g in 40 g of tetrahydrofuran was added thereto, and the mixture was further stirred for 1 hour. The coating solution thus prepared was applied onto an aluminum support using a Mayer bar and dried until the film thickness was 20 mm.
A photosensitive layer of μm was formed. The charging characteristics of the electrophotographic photoreceptor thus prepared were evaluated in the same manner as in Example 1. The charging was positive. V0: +700V, E1/2: 2.0 lux/sec.

[0049]

Effects of the Invention The electrophotographic photoreceptor of the present invention uses a compound with a specific structure in the photosensitive layer, so that the electrophotographic properties of the electrophotographic photoreceptor have high sensitivity and continuous image formation by repeated charging and exposure. It is effective in exhibiting the remarkable effect of having small fluctuations in bright area potential and dark area potential and excellent durability. Furthermore, similar effects can be achieved in an electrophotographic apparatus and a facsimile equipped with the electrophotographic photoreceptor.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a general transfer type electrophotographic apparatus.

FIG. 2 is a block diagram of a facsimile machine using an electrophotographic device as a printer.

[Explanation of symbols]

1 Drum-type photoreceptor as an image carrier (electrophotographic photoreceptor of the present invention) 1a Shaft 2 Corona charging device 3 Exposure section 4 Developing means 5 Transfer means 6 Cleaning means 7 Pre-exposure means 8 Image fixing means L Optical image Exposure P Transfer material 10 that has undergone image transfer Image reading unit 11 Controller 12 Receiving circuit 13 Transmitting circuit 14 Telephone 15 Line 16 Image memory 17 CPU 18 Printer controller 19 Printer

Claims (4)

[Claims] 1. An electrophotographic photoreceptor comprising a photosensitive layer containing an azo pigment represented by the following general formula (1) on a conductive support. General formula (1) In the formula, R1 and R2 are the same or different and are hydrogen atoms,
It represents a halogen atom, an alkyl group, or an aryl group which may have a substituent, and A1 and A2 are the same or different and represent a coupler residue having a phenolic hydroxyl group. 2. The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer comprises at least two layers: a charge generation layer containing an azo pigment represented by 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 means for receiving image information from a remote terminal.