JPH04256960A - Electrophotographic sensitive body and electrophotographic device and facsimile having this electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the electrophotographic sensitive body having a practicable high-sensitivity characteristic and stable potential characteristics at the time of repetitive use by providing a photosensitive layer contg. a specific disazo pigment. CONSTITUTION:The electrophotographic sensitive body has the photosensitive layer contg. the disazo pigment expressed by formula I. In the formula I, A1 and A2 may be the same or different and denote a residual coupler group having a phenolic hydroxyl group and a preferable example thereof includes the residual group expressed by formula II. In the formula II, X denotes the residual group necessary for forming polycyclic arom. rings or heterocycles, such as naphthanlene ring, anthracene ring, carbazole ring, benzcarbazole ring, and dibenzofuran, which may have a substituent by condensing with a benzene ring. R1 and R2 denote a hydrogen atom, an alkyl group, aryl group, aralkyl group or heterocyclic group which may have a substituent. Z denotes an oxygen atom or sulfur atom; p denotes 0 or 1 integer.

Description

[Detailed description of the invention]

0001

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

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-57-
182748, JP-A-54-22834, etc. are already known. However, conventional electrophotographic photoreceptors using disazo pigments have not always been sufficient in terms of sensitivity and potential stability during repeated use.

0004

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel photoconductive material and 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.

[0005]

[Means for Solving the Problems] The present invention comprises an electrophotographic photoreceptor characterized in that it has a photosensitive layer containing a disazo pigment represented by the following general formula (1) on a conductive support. General formula (1) Chemical formula 2 In the formula, A1 and A2 are the same or different and represent a coupler residue having a phenolic hydroxyl group.

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 (7).

General formula (2) 3

General formula (3) 4

General formula (4) 5

General formula (5) 6

General formula (6) 7

General formula (7) 8

General formulas (2), (3), (4) and (5
) is a residue necessary for condensation with a benzene ring to form a polycyclic aromatic ring or heterocycle such as a naphthalene ring, anthracene ring, carbazole ring, benzcarbazole ring, or dibenzofuran ring, which may have a substituent. The general formula (
Y in 7) 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-pyrazo-
Examples include divalent groups such as ludiyl, 2,3-pyridinediyl, 4,5-pyridinediyl, 6,7-indazoldiyl, 6,7-quinolinediyl, and the like in general formulas (2) and (3). R1 and R2 represent a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group which may have a substituent, and R1 and R2 both form a cyclic amino group via a nitrogen atom. R3 in the general formulas (4) and (5) 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 (6) R4 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;
Cyclic amino groups containing a nitrogen atom in the ring include pyrrole,
Examples include pyrroline, pyrrolidine, pyrrolidone, indole, indoline, carbazole, imidazole, pyrazole, pyrazoline, oxazine, and phenoxazine. Substituents include halogen atoms such as fluorine, chlorine, iodine, and bromine; alkyl groups such as methyl, ethyl, and propyl; alkoxy groups such as methoxy and ethoxy;
Examples include alkylamino groups such as dimethylamino and diethylamino, phenylcarbamoyl groups, nitro groups, cyano groups, and halomethyl groups such as trifluoromethyl.
Z in general formulas (2) and (4) represents an oxygen atom or a sulfur atom, and p is an integer of 0 or 1.

Note that A1 and A in general formula (1)
A pigment using a coupler in which 2 is the general formula (2), (3), (4) or (5), and X in the formula is fused with a benzene ring to form a benzcarbazole ring, Because its absorption range extends to near the near-infrared region, semiconductor lasers
It is also suitable as a charge-generating material for use in other applications.

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 a disazo 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 disazo pigment represented by the general formula (1) of the present invention are listed in the following table, 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.

Table 1 Table 2 Table 3 Table 4 Table 5 Table 6 Table 7 Table 8 Table 9 Table 10 Table 11 Table 12 Table 13 Table 14 Table 15 Table 16 Table 17

The disazo pigment represented by the general formula (1) can be produced 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 the tetrazonium salt into a borofluoride salt or a zinc chloride double salt. After converting the coupler into
It can be easily synthesized by coupling with

When synthesizing a disazo pigment in which A1 and A2 in general formula (1) are different couplers,
Synthesis can be carried out by first coupling 1 mol of one coupler and then 1.05 mol of the other coupler to 1 mol of the above-mentioned tetrazonium salt, or by converting one amino group of the diamine into an acetyl group. etc., diazotize this, couple one coupler, hydrolyze the protecting group with hydrochloric acid etc., diazotize it again and couple the other coupler to synthesize. Can be done.

Synthesis Example (Synthesis of Pigment 1) 150 ml of water in a 300 ml beaker,
Add 20 ml (0.23 mol) of concentrated hydrochloric acid and 7.2 g (0.032 mol) of chemical formula 9 and cool to 0°C.
A solution of 4.6 g (0.067 mol) of sodium nitrite dissolved in 10 milliliters of water was heated for 1 hour while keeping the temperature of the solution below 2°C.
It was dropped in 0 minutes. After stirring for 15 minutes, carbon filtration was performed, and 10.5 g (0.09 g) of sodium borofluoride was added to this solution.
A solution prepared by dissolving 6 moles of fluoride in 90 milliliters of water was added dropwise under stirring, and the precipitated borofluoride salt was collected by filtration, washed with cold water and then with acetonitrile, and dried under reduced pressure at room temperature. Yield 10.6g, yield 78.1%

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., 8.5 g (0.020 mol) of the borofluoride salt obtained earlier was dissolved,
Then, 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 10.7g, yield 69.0%

Elemental analysis value C Calculated value 71.3%, Actual value 71.5% H Calculated value 3.9%, Actual value 3.9% N Calculated value 14.5%,
Actual value 14.7%

The electrophotographic photoreceptor of the present invention has a photosensitive layer containing a disazo pigment represented by the general formula (1) on a conductive support. The photosensitive layer may take any known form, but the photosensitive layer containing a disazo pigment represented by general formula (1) is used as a charge generation layer,
Particularly preferred is a functionally separated type photosensitive layer in which a charge transport layer containing a charge transport substance is laminated thereon.

The charge generation layer can be formed by coating a coating solution in which the disazo 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 For example, the thickness is 5 μm or less,
Preferably, the thickness is preferably 0.1 to 1 μm. The binder resin used in this case is selected from a wide range of insulating resins and organic photoconductive polymers.
Substituted or unsubstituted polyvinyl butyral, polyvinyl benzal, polyarylate, polycarbonate, polyester, phenoxy resin, cellulose resin, acrylic resin, polyurethane, etc. are preferred, and the amount used is 80% by weight in the charge generation layer. Below, 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, N,N
-Amides such as dimethylformamide, methyl acetate,
Esters such as ethyl acetate, aromatics such as toluene, xylene, and chlorobenzene, alcohols such as methanol, ethanol, and 2-propanol, and aliphatic halogens such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, and trichlorethylene. Examples include hydrogenated hydrocarbons.

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]-
Styryl compounds such as 5H-dibenzo[a,d]cycloheptene, benzidine compounds, triarylmethane compounds, triarylamine compounds, triphenylamine, or groups consisting of these compounds in the main chain or side chain Examples include polymers (eg, poly-N-vinylcarbazole, polyvinylanthracene, etc.). 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 polyN-vinylcarbazole and polyvinylanthracene. Examples include polymers.

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 disazo 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 above-mentioned disazo pigment and charge transfer complex are dispersed in a suitable resin solution. The pigment used in any electrophotographic photoreceptor is a disazo pigment represented by the general formula (1). The crystal form of the disazo pigment may be amorphous or crystalline. It is also possible to use a combination of two or more types of disazo pigments shown, or a 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 10 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, 105 g of a hydrazone compound shown by the following structural formula and polymethyl methacrylate (weight average molecular weight 10
Example 1 An electrophotographic photoreceptor was prepared.

Electrophotographic photoreceptors corresponding to Examples 2 to 10 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 E1/6 required for the surface potential to attenuate to 1/6 after being left in a dark place were measured. Show the results.

Example 1 Pigment 1 V0: -700V, E1/6: 1.
2 lux/second Example 2 Pigment 3 V0: -700V, E1/6: 1.
1 lux/second Example 3 Pigment 11 V0: -700V, E1/6: 1.1
Lux/Second Example 4 Pigment 15 V0: -705V, E1/6: 1.4
Lux/Second Example 5 Pigment 22 V0: -700V, E1/6: 1.0
Lux/Second Example 6 Pigment 25 V0: -680V, E1/6: 1.6
Lux/Second Example 7 Pigment 43 V0: -695V, E1/6: 1.3
Lux/Second Example 8 Pigment 49 V0: -695V, E1/6: 1.3
Lux/Second Example 9 Pigment 57 V0: -700V, E1/6: 1.2
Lux/Second Example 10 Pigment 78 V0: -710V, E1/6: 1.0
looks second

Comparative Examples 1 and 2 Electrophotographic photoreceptors were prepared in the same manner as in Example 1, except that the disazo pigment used in Example 1 was replaced with Comparative Pigments 1 and 2 shown in Table 18, and charged in the same manner. Characteristics were evaluated. Show the results. Table 18 Comparative Example 1 Comparative Pigment 1 V0: -630V, E1/6: Unable to measure Comparative Example 2 Comparative Pigment 2 V0: -680V, E1/6: 4.
7 lux/sec These results show that the electrophotographic photoreceptor of the present invention has sufficient charging ability and excellent sensitivity.

Examples 11 to 15 The electrophotographic photoreceptors prepared in Examples 1, 2, 4, 5, and 9 were charged with a -6.5 KV corona charger, an exposure light system, a developer, a transfer charger, It was attached to the cylinder of an electrophotographic copying machine equipped with a static elimination exposure optical system and a cleaner. The initial dark potential VD and light potential VL are each -700V,
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 voltage was set at around -200V and the device was repeatedly used 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 11 ΔVD: -10V, ΔVL: 0V Example 12 ΔVD: 0V, ΔVL: +5V Example 13 ΔVD: 0V, ΔVL: +5V Example 14
ΔVD: -5V, ΔVL: 0V Example 15
ΔVD: -15V, ΔVL: +10V

[0044]
Comparative Examples 3 and 4 Regarding the electrophotographic photoreceptors prepared in Comparative Examples 1 and 2,
By the same method as in Example 11, potential fluctuations during repeated use were measured. Show the results. Example 3 ΔVD: -55V, ΔVL: +20V
Example 4 ΔVD: -40V, ΔVL: +30V
From the above results, it can be seen that the electrophotographic photoreceptor of the present invention has little potential fluctuation during repeated use.

Example 16 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 3 was applied with a Mayer 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 film with a thickness of 19 μm. A transport layer was formed. The charging characteristics and durability characteristics of the produced electrophotographic photoreceptor were measured by the same method as in Examples 1 and 11. Show the results. V0: -700V, E1/6: 1.1 lux/sec, ΔVD: -5V, ΔVL: 0V

[0046]
Example 17 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 fluorene 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 film with a thickness of 21 μm. A transport layer was formed. The charging characteristics and durability characteristics of the produced electrophotographic photoreceptor were measured by the same method as in Example 1. Show the results. V0: -700V, E1/6: 1.1 lux seconds, Δ
VD: 0V, ΔVL: 0V

Example 18 An electrophotographic photoreceptor was prepared by applying the charge generation layer and charge transport layer of the electrophotographic photoreceptor prepared in Example 5 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, E1/6: 0.9
looks second

Example 19 5 g of 2,4,7-trinitro-9-fluorenone and poly-4,4'-dioxydiphenyl-2,2-propane carbonate were placed on the charge generating layer prepared in Example 5. A solution prepared by dissolving 5 g (molecular weight: 300,000) in 50 g of tetrahydrofuran was applied using a Meyer bar to form a charge transport layer having a thickness of 19 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: +685V, E1/6: 1.
2 lux seconds.

Example 20 0.5 g of Pigment 7 was dispersed with 9.5 g of cyclohexanone in a paint shaker for 5 hours. Here, 5 g of the same charge transport material used in Example 1 and 5 g of polycarbonate were added.
A solution of 40 g of tetrahydrofuran was added thereto, and the mixture was further stirred for 1 hour. The coating solution thus prepared was coated onto an aluminum support using a Meyer bar and dried to a film thickness of 18 μm.
A photosensitive layer of m 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: +690V, E1/6: 1.0
Looks Sec.

[0050]

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 section 11 Controller 12 Receiving circuit 13 Transmitting circuit 14 Telephone 15 Line 16 Image memory 17 CPU 18 Printer controller 19 Printer

Claims (1)

Scope of the Claims: [Claim 1] An electrophotographic photoreceptor comprising a photosensitive layer containing a disazo pigment represented by the following general formula (1) on a conductive support. General formula (1) Chemical formula 1 (In the formula, 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 a disazo 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.