JPH04344653A - Electrophotographic photoreceptor, electrophotographic device equipped with the electrophotographic photoreceptor, and facsimile - Google Patents

Abstract

PURPOSE:To obtain excellent high sensitivity characteristics, especially, stable potential characteristics at the time of repeated uses by forming a photosensitive layer containing a specified disazo pigment on a conductive substrate. CONSTITUTION:The photosensitive layer contains the disazo pigment represented by formulae I and/or II in which each of A1 and A2 is, independently, a coupler residue represented by formula III; X is an atomic group necessary to combine with the benzene ring to form a polycyclic aromatic ring, such as naphthalene or anthracene, or a hetero ring; Z is an 0 or S atom; and each of R1 and R2 is, independently, H, optionally substituted alkyl, such aryl, such aralkyl, or such a heterocyclic group, or each may combine with each other to form a cyclic group together with the N atom.

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 compounds with various properties can be obtained relatively easily by combining the azo component and the coupler component, so many compounds have been developed to date. It has been proposed, JP-A-1-1
Publication No. 80553, Japanese Unexamined Patent Publication No. 1-319754, and the like are known. However, electrophotographic photoreceptors using conventional disazo pigments are not necessarily satisfactory in terms of sensitivity and potential stability during repeated use, and only a few materials have been put into practical use. .

0004

SUMMARY OF THE INVENTION The objects of the present invention are to provide a novel photoconductive material, an electrophotographic photoreceptor having excellent 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 provides an electrophotographic photoreceptor characterized in that it has a photosensitive layer containing a disazo pigment represented by the following general formula (1) and/or (2) on a conductive support. It consists of

General formula (1)

[C4]

General formula (2)

[Image Omitted] In the formula, A1 and A2 are the same or different and represent the general formula (3
) represents a coupler residue.

General formula (3)

embedded image In the 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 are the same or Each represents an alkyl group, an aralkyl group, an aryl group, or a heterocyclic group which may have a hydrogen atom or a substituent, and R1 and R2 may be bonded to each other to form a ring with a nitrogen atom. .

Specifically, X in the general formula (3) includes a residue necessary to form a ring such as a naphthalene ring, an anthracene ring, a carbazole ring, a benzcarbazole ring, a dibenzofuran ring, and R1 and R2 is an alkyl group such as methyl, ethyl, propyl, an aralkyl group such as benzyl, phenethyl, an aryl group such as phenyl, naphthyl, anthryl, a heterocyclic group such as pyridyl, thienyl, carbazolyl, benzimidazolyl, benzothiazolyl, or pyrrole. , pyrroline, pyrrolidine, pyrrolidone, indole, indoline, carbazole, imidazole,
Examples include cyclic amino groups containing a nitrogen atom in the ring, such as pyrazole, pyrazoline, oxazine, and phenoxazine. Examples of substituents include halogen atoms such as fluorine atoms, chlorine atoms, and bromine atoms, methyl, and ethyl. , alkyl groups such as propyl, alkoxy groups such as methoxy and ethoxy, alkylamino groups such as dimethylamino and diethylamino, phenylcarbamoyl groups, nitro groups, cyano groups, and halomethyl groups such as trifluoromethyl groups.

The present invention also provides an electrophotographic photosensitive layer 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/or (2) and a charge transport layer. Consists of the body. In addition, the general formula (3
), in which X is a coupler residue forming a benzcarbazole ring, the pigment has an absorption range that extends to near the near-infrared region, so it can also be used as a charge-generating material for semiconductor lasers. suitable.

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 specific examples of the disazo pigments represented by the general formula (1) and/or (2) of the present invention are shown in Tables 1 to 1.
However, the disazo 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.

[0014]

[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]

The disazo pigments represented by general formulas (1) and (2) are produced by tetrazotizing the corresponding diamine by a conventional method.
Coupling with the coupler in an aqueous system in the presence of an alkali, or converting the tetrazonium salt into a borofluoride salt or zinc chloride double salt, is followed by acetic acid solution 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 da, triethylamine, or N-methylmorpholine.

A1 and A2 in general formulas (1) and (2)
When synthesizing disazo pigments in which are different couplers, first 1 mol of one coupler is coupled to 1 mol of the above-mentioned tetrazonium salt, and then 1 mol of the other coupler is coupled. Alternatively, one amino group of the diamine is protected with an acetyl group, etc., this is diazotized, one coupler is coupled, the protecting group is hydrolyzed with hydrochloric acid, etc., and this is diazotized again. It can be synthesized by coupling the other coupler.

Synthesis Example (Synthesis of Exemplary Pigment (1)) In a 300 ml beaker, add 150 ml of water and 2 ml of concentrated hydrochloric acid.
0ml (0.23mol)

Add 13.4 g (0.032 mol) of [Chemical 7] and cool it to 0°C, and then dissolve 4.6 g (0.067 mol) of sodium nitrite in 10 ml of water and lower the temperature to 5°C. 10 while keeping
It was dripped in minutes. After stirring for 15 minutes, carbon filtration was carried out.
Add 10.5 g (0.096 g) of sodium borofluoride to this solution.
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 1
6.0 g, yield 81.3%. Next, put 500 ml of DMF into a 1 liter beaker,

After dissolving 12.9 g (0.042 mol) of [Chemical 8] and cooling the liquid temperature to 5°C, 12.3 g (0.0 mol) of the borofluoride salt obtained earlier was dissolved.
20 mol) and then 5.1 g of triethylamine
(0.050 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 17.9g, Yield 85.0
%.

The electrophotographic photoreceptor of the present invention has a photosensitive layer containing a disazo pigment represented by the general formula (1) and/or (2) on a conductive support. The form of the photosensitive layer may be any known form, but may be formed by the general formula (1
Particularly preferred is a functionally separated type photosensitive layer in which a photosensitive layer containing a disazo pigment as shown in ) and/or (2) is used as a charge generating layer, and a charge transporting layer containing a charge transporting substance is laminated thereon.

The charge generation layer can be formed by coating a coating solution in which the above-mentioned disazo pigment 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.
Preferred are polyvinyl butyral, polyvinyl benzal, polyarylate, polycarbonate, polyester, phenoxy resin, cellulose resin, acrylic resin, polyurethane, etc., and the content thereof in the charge generation layer is 80% by weight or less, preferably 40% by weight. % 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 2,4
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.

[0022] 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. In any electrophotographic photoreceptor, the crystal form of the disazo pigment represented by the general formulas (1) and (2) may be amorphous or crystalline, and if necessary, the crystal form of the disazo pigment represented by the general formula (1) may be amorphous or crystalline. It is also possible to use a combination of two or more types of disazo pigments shown in ) and (2), or to use them in combination with a known charge-generating substance.

The electrophotographic photoreceptor of the present invention can be used not only in electrophotographic copying machines, but also in 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 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, 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. Furthermore, when the electrophotographic apparatus is used as a copying machine or a printer, the light image exposure L can be carried out using reflected light or transmitted light from the original, or by reading the original and converting it into a signal, and then using a laser according to this signal. This is performed by scanning a beam, driving a light emitting diode array, or driving a liquid crystal shutter array. Furthermore, when used as a facsimile printer, the optical image exposure L is exposure 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 out 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.

[0027]

【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: 33,000) were placed on an aluminum support in 90 g of methanol.
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, add 4.5 g of Pigment 1 to 85 g of cyclohexanone and add butyral resin (butyralization degree: 72 mol%).
2 g was added to the dissolved liquid and dispersed with a sand mill for 18 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 following structural formula and

[Chemical formula 9] Polymethyl methacrylate (weight average molecular weight 90,000) 5g
was dissolved in 40 g of chlorobenzene and spread on a Meyer bar so that the dry film thickness was 22 μm.
The electrophotographic photoreceptor of Example 1 was prepared by coating and drying to form a charge transport layer.

Example 2 Using another pigment in place of Pigment 1
Electrophotographic photoreceptors corresponding to Examples 1 to 22 were prepared in exactly the same manner.

The produced electrophotographic photoreceptor was manufactured by Kawaguchi Electric Co., Ltd.
The paper was negatively charged with a corona discharge of -5 KV using an electrostatic copying paper tester Model SP-428 manufactured by Manufacturer Co., Ltd. After being held in a dark place for 1 second, it was exposed to light using a halogen lamp at an illuminance of 10 lux to evaluate the charging characteristics. . 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: -710V, E1/2: 1.20
Lux/Second Example 2 Pigment 2 V0: -700V, E1/2: 1.10
Lux/Second Example 3 Pigment 3 V0: -720V, E1/2: 1.30
Lux/Second Example 4 Pigment 4 V0: -700V, E1/2: 1.25
Lux/Second Example 5 Pigment 8 V0: -690V, E1/2: 1.35
Lux/Second Example 6 Pigment 9 V0: -700V, E1/2: 1.10
Lux/sec Example 7 Pigment 10 V0: -700V, E1/2: 1.30 lux/sec Example 8 Pigment 14 V0: -690V, E1/2: 1.30 lux/sec Example 9 Pigment 18 V0: -700V, E1/2: 1.10 lux/sec Example 10 Pigment 24 V0: -700V, E1/2: 1.40 lux/sec Example 11 Pigment 37 V0: -700V, E1/2: 0.75 Lux/sec Example 12 Pigment 40 V0: -710V, E1/2: 0.70 Lux/sec Example 13 Pigment 42 V0: -700V, E1/2: 1.00 Lux/sec Example 14 Pigment 43 V0: -690V, E1/2: 1.35 lux/sec Example 15 Pigment 46 V0: -700V, E1/2: 1.30 lux/sec Example 16 Pigment 56 V0: -700V, E1/2: 1.20 Lux/sec Example 17 Pigment 62 V0: -700V, E1/2: 1.25 Lux/sec Example 18 Pigment 65 V0: -710V, E1/2: 1.45 Lux/sec Example 19 Pigment 66 V0: -700V, E1/2: 1.45 lux/sec Example 20 Pigment 68 V0: -700V, E1/2: 1.40 lux/sec Example 21 Pigment 69 V0: -700V, E1/2: 1.10 Lux/second Example 22 Pigment 70 V0: -700V, E1/2: 1.45 lux/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 17 below. The charging characteristics were evaluated. Show the results.

[Table 17]

Comparative Example 1 Comparative Pigment 1 V0: -700V, E1/2: 3.55
Lux/seconds comparison example 2 Comparative pigment 2 V0: -680V, E1/2: 2.70
Lux/sec This result shows 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 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. It was attached to the cylinder of an electrophotographic copying machine. The initial dark potential VD and bright potential VL are set to around -700V and -200V, respectively.
The variation amount ΔVD in the dark area potential and the variation amount ΔVL in the light area potential were measured after repeated use 5,000 times. Examples 2, 3, 4
, 5, 6, 7, 8, 9, 11, 12, 13 and 17 were also evaluated in the same manner. 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 23 ΔVD: -5V, ΔVL:
+5V Example 24 ΔVD: -5V, ΔVL
: 0V Example 25 ΔVD: -10V,
ΔVL: +5V Example 26 ΔVD: −
5V, ΔVL: 0V Example 27 ΔVD
: 0V, ΔVL: +5V Example 28
ΔVD: 0V, ΔVL: +5V Example 2
9 ΔVD: 0V, ΔVL: +10V Example 30 ΔVD: -10V, ΔVL: +5
V Example 31 ΔVD: 0V, ΔVL:
+10V Example 32 ΔVD: +5V, ΔV
L: +5V Example 33 ΔVD: 0
V, ΔVL: +5V Example 34 ΔVD:
-5V, ΔVL: +5V Example 35 ΔV
D: -10V, ΔVL: 0V

Comparative Examples 3 and 4 Regarding the electrophotographic photoreceptors prepared in Comparative Examples 1 and 2,
By the same method as in Example 23, potential fluctuations during repeated use were measured. Show the results. Comparative example 3 ΔVD: -50V, ΔVL: +60V
Comparative example 4 ΔVD: -90V, ΔVL: +75V
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 0.4 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 Meyer bar and dried, resulting in a film thickness of 0.3
A charge generation layer of .mu.m was formed.

Next, a styryl compound 4.5 having the following structural formula
g and

embedded image A solution obtained by dissolving 5 g of polycarbonate (weight average molecular weight: 35,000) in 40 g of tetrahydrofuran was applied onto the charge generation layer and dried to form a charge transport layer with a thickness of 18 μm. 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. V0: -680V, E1/2: 1.05 lux/second Δ
VD: 0V, ΔVL: +5V

Example 37 An electrophotographic photoreceptor was prepared by applying the charge generation layer and charge transport layer of the electrophotographic photoreceptor prepared in Example 2 in the reverse order, and the charging characteristics were evaluated in the same manner as in Example 1. . However, the charging was positive. V0: +700V, E1/2: 1.60 lux/sec.

Example 38 On the charge generation layer prepared in Example 2, 4.5 g of 2,4,7-trinitro-9-fluorenone and poly-4,4'-dioxydiphenyl-2,2-propane carbonate were added. A solution prepared by dissolving 5 g of 2-glute (molecular weight 300,000) in 50 g of tetrahydrofuran was applied using a Mayer bar, and the film thickness after drying was 21 μm.
A charge transport layer was formed. The charging characteristics of the produced electrophotographic photoreceptor were evaluated in the same manner as in Example 1. However, the charging was positive. V0: +690V, E1/2: 3.30 lux/sec

[
Example 39 0.5 g of Pigment 2 was dispersed with 9.5 g of cyclohexanone in a paint shaker for 5 hours. A solution prepared by dissolving 4.5 g of the same charge transport material used in Example 1 and 5 g of polycarbonate in 40 g of tetrahydrofuran was added thereto.
I rested for another hour. The coating solution thus prepared was applied onto an aluminum support using a Meyer bar and dried until the film thickness was 1.
A photosensitive layer of 8 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: +675V, E1/2: 3.80 lux/sec

[
0043

Effects of the Invention In the electrophotographic photoreceptor of the present invention, by using a disazo pigment with a specific structure in the photosensitive layer, the generation efficiency and/or injection efficiency of charge carriers placed inside the photosensitive layer is improved. , the electrophotographic photoreceptor has the remarkable effect of providing excellent characteristics in terms of sensitivity and potential stability during repeated use, and the same remarkable effect can also be achieved in electrophotographic devices and facsimile machines 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) 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 Photoimage 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 (4)

[Claims] 1. An electrophotographic photoreceptor having a photosensitive layer on a conductive support, characterized in that the photosensitive layer contains a disazo pigment represented by the general formula (1) and/or the general formula (2). Electrophotographic photoreceptor. General formula (1) [Formula 1] General formula (2) [Formula 2] In the formula, A1 and A2 are the same or different and represent the general formula (3
) represents a coupler residue. General formula (3) [Chemical formula 3] In the 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 are the same or different and represent a hydrogen atom, an alkyl group that may have a substituent, an aralkyl group, an aryl group, or a heterocyclic group, and R1 and R2 are bonded to each other to form a ring together with a nitrogen atom. may be formed. 2. The photosensitive layer has the general formula (1) and/or (
2. The electrophotographic photoreceptor according to claim 1, comprising at least two layers: a charge generation layer containing the disazo pigment shown in 2) 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.