JPH04118660A - Electrophotographic sensitive body, electrophotographic device and facsimile having this electrophotographic body - Google Patents

Abstract

PURPOSE:To enhance the sensitivity characteristics of the photosensitive body and to stabilize the potential characteristics in repetitive use by incorporating a specific trisazo pigment into a photosensitive layer. CONSTITUTION:The trisazo pigment expressed by general formula I is incorporated into the photosensitive layer of this photosensitive body. In the formula, Ar1, Ar2 denote a carbon cyclic arom. group or heterocyclic arom. group; A1 and A2 denote a residual coupler group having a phenolic hydroxyl group. The more specific examples of the pigment of the formula include the compd., both of A1, A2 are the groups of formula II, etc. The photosensitive layer is preferably formed of at least the two layers; the charge generating layer contg. the trisazo pigment of the formula and a charge transfer layer.

Description

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

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

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

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

Azo pigments exhibit excellent photoconductivity, and because compounds with various properties can be easily obtained by combining the azo component and coupler component, many compounds have been proposed so far, such as JP-A-54-22834, JP-A-56-116040, JP-A-58-
Publication No. 70232, Japanese Unexamined Patent Publication No. 131539/1983,
JP-A-61-215556 and JP-A-61-2
No. 41763 is already known.

However, conventional electrophotographic photoreceptors using azo pigments are not necessarily satisfactory in terms of sensitivity and potential stability during repeated use, and only the azo material has been put into practical use.

[Problems to be Solved by the Invention] The purpose of the present invention is to provide a new type of photoconductive material, and to provide an electrophotographic photoreceptor having practical high sensitivity characteristics and stable potential characteristics during repeated use. Particularly, it is an object of the present invention to provide an electrophotographic apparatus and a facsimile equipped with the electrophotographic photoreceptor.

[Means for Solving the Problems, Effects] The present invention is an electrophotographic photoreceptor having a photosensitive layer on a conductive support, characterized in that the photosensitive layer contains a trisazo pigment represented by the following general formula (1). Consists of an electrophotographic photoreceptor.

In the general formula, A r l! 3 and Ar2 are the same or different and represent a carbocyclic aromatic group or a heterocyclic aromatic 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, the carbocyclic aromatic group in A r + and A r w includes a group obtained by removing two hydrogen atoms from a carbocyclic aromatic ring such as benzene, naphthalene, and anthracene, and a heterocyclic aromatic group. Examples include groups in which two hydrogen atoms are removed from a heterocyclic aromatic ring such as furanvirol carboxylic acid, thiophene, pyridine, and pyrazine, and substituents include halogen atoms such as fluorine, chlorine, iodine, and bromine, Alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, alkoxy groups such as methoxy, ethoxy, propoxy, aryloxy groups such as phenoxy,
Examples include substituted amino groups such as nitro group, cyano group, dimethylamino, dibenzylamino, diphenylamino, morpholino, piperidino, and pyrrolidino.

Preferred examples of the coupler residues having a phenolic hydroxyl group represented by A1 and A2 include residues represented by the following general formulas (2) to (6).

In general formulas (2), (3), and (4), Represents residues necessary to form an aromatic ring or a heterocycle.

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, and specifically, O-phenylene, ○-Naphthylene, berinaphthylene, 12-antrylene, 3,4-
Pyrazolediyl 2,3-pyridinediyl, 4,5-pyridinediyl, 6,7-indazolediyl, 6,7-
Examples include divalent groups such as chiralediyl.

R and R2 in general formulas (2) and (3) represent a hydrogen atom, an alkyl group that may have a substituent, an aryl group, an aralkyl group, or a heterocyclic group, and R1, Rz
may be combined with a nitrogen atom to form a cyclic amino group containing a nitrogen atom in the ring.

R1 in 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.

R4 in formula (5) represents a hydrogen atom, an alkyl group that may have a substituent, an aryl group, an aralkyl group, or a heterocyclic group.

Examples of alkyl groups in the above expression include methyl, ethyl, and propyl; specific examples of aryl groups include phenyl, naphthyl, and anthryl; aralkyl groups include benzyl and phenethyl; heterocyclic groups include pyridyl; Groups such as thienyl, carbazolyl, benzimidazolyl, and benzothiazolyl, and cyclic amino groups containing a nitrogen atom in the ring include virol, pyrroline, pyrrolidine, pyrrolidone, indole, indoline, carbazole, imidazole, pyrazole, pyrazoline, oxazine, and phenoxazine. It will be done.

Examples of 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; alkylamino groups such as dimethylamino and diethylamino;
Examples include a phenylcarbamoyl group, a nitro group, a cyano group, and a helomethyl group such as trifluoromethyl.

Z in formula (2) represents an oxygen atom or a sulfur atom, and 2
is an integer of 0 or 1.

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 trisazo pigment represented by general formula (1) and a charge transport layer.

In addition, in general formula (1), A1. A2 is general formula (2), (
3) or (4), in which ¥1 is a coupler residue condensed with a benzene ring to form a benzcarbazole ring, the pigment has an absorption range near the near-infrared region. Because it spreads, it is also suitable as a charge-generating material for semiconductor lasers.

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

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

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

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

Basic type exemplified pigment (1) Ar h Art: exemplified pigment (2) ArhArt: exemplified pigment (3) Art, Ar2: + exemplified pigment (4) l2 ArhArt: + exemplified pigment Art, Art:+ exemplified pigment exemplified pigment Art %Art: + Exemplary Pigment (8) Exemplary Pigment Ar・Arz: Exemplary Pigment (10) Exemplary Pigment (11) Ar, Am: CJ* Ar・rz: (Exemplary Pigment (12) Exemplary Pigment (13) H Art, Art: -@)- Exemplary pigment r h r 2 ・÷ Exemplary pigment (15) Art, Art: ? Exemplary Pigment (16) A,, lkt: Exemplary Pigment A r + , r z All Exemplary Pigments Ar+ , Arz : + Exemplary Pigment (19) Ar+ , Arz : + Exemplary Pigment (20) Exemplary Pigment (21) Exemplary Pigment (22 ) Exemplary Pigment (23) Exemplary Pigment (24) Exemplary Pigment (25) Exemplary Pigment (26) Exemplary Pigment (27) r r z Knee e- Exemplary Pigment (28) r, Art: + Exemplary Pigment (29) ArhArt: Base Exemplary Pigment (30) Ar, Ar2: Exemplary Pigment (31) Art, Arz 4 Exemplary Pigment (32) ArhArm: Exemplary Pigment (33) Ar Art: Zuto Exemplary Pigment (34) Trisazo represented by general formula (1) The pigment is produced by tetrazotizing the corresponding diamine by a conventional method, coupling it with a coupler in an aqueous system in the presence of an alkali, or converting the tetrazonium salt into a borofluoride salt, zinc chloride double salt, etc.
It can be easily synthesized by coupling with a coupler in an organic solvent such as dimethylformamide or dimethyl sulfoxide in the presence of a base such as sodium acetate, triethylamine, or N-methylmorpholine.

When synthesizing a trisazo pigment in which A and A in general formula (1) 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. It can be synthesized by coupling 1 mole of coupler, or one amino group of the diamine is protected with an acetyl group, etc., this is diazotized, one coupler is coupled, and the protecting group is hydrated with hydrochloric acid etc. It can be synthesized by decomposing it, diazotizing it again, and coupling it with the other coupler.

Synthesis example (synthesis of exemplified pigment (1)) 150 mj2 of water and 20 m concentrated hydrochloric acid in a 300 mj2 beaker
12 (0.23 mol) and (0,032 mol) were added and cooled to 0℃, and a solution of 4.6 g (0,067 mol) of sodium nitrite dissolved in 10 ml of water was added while maintaining the liquid temperature at 5℃. It was added dropwise over 10 minutes.

After stirring for 15 minutes, carbon filtration was performed, and in this solution, 10.5 g (0,096 mol) of sodium fluoride was added to 9 mol of water.
The solution dissolved in 0 m2 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: 13.7 g, Yield: 92.0% Next, put 500 m 12 of DMF in a 142 beaker, dissolve it, cool the liquid temperature to 5°C, and then add 9.3 g (0 ,020 mol) and then 5.1 g (0,050 mol) of triethylamine
It was dripped in 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 14.2 g, yield 87% Elemental analysis calculated value (%) Actual value (%) C70,5870,63 H3,953,97 N 13.72 13.73 The electrophotographic photoreceptor of the present invention has a conductive support. General formula (
It has a photosensitive layer containing the trisazo pigment shown in 1).

The form of the photosensitive layer may be any known form, but a photosensitive layer containing a trisazo pigment represented by general formula (1) is used as a charge generation layer, and a charge transport layer containing a charge transport substance is laminated thereon. A functionally separated type photosensitive layer is particularly preferred.

The charge generation layer can be formed by coating a coating liquid in which the above-mentioned azo pigment is dispersed together with a binder resin in a suitable solvent on a conductive support by a known method, and the film thickness thereof is, for example, 5 μm. Below, preferably 0.1
A thin film layer of ~1 μm is desirable.

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

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

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, xylene, Examples include aromatics such as chlorobenzene, alcohols such as methanol, ethanol, and 2-propanol, and aliphatic halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, and trichlorethylene.

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

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

Charge transporting substances include electron transporting substances and hole transporting substances. Examples of electron transporting substances include 2゜4,7-dolinitrofluorenone, 2,4,5゜7-titranitrofluorenone, chloranil, and tetranitrofluorenone. Examples include electron-withdrawing substances such as cyanoquinodimethane, and polymerization 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, pyrazole-based pyrazoline-based, thiadiazole-based, triazole-based compounds, etc. heterocyclic compound, p-
Hydrazone-based compounds such as diethylaminobenzaldehyde-N,N-diphenylhydrazone, N,N-diphenylhydrazino-3-methylidene-9-ethylcarbazole, α-phenyl-4°-N, N-diphenylaminostilbene, 5-[ 4-(di-p-tolylamino)
benzylidene] -5H~dibenzo[a,d]cycloheptene, a styrene-based compound, a benzidine-based compound, a triarylmethane-based compound, triphenylamine, or a group consisting of these compounds in the main chain or side chain. (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 poly-N-vinylcarbazole and polyvinylanthracene. Polymers and the like can be mentioned.

Examples of the conductive support on which the photosensitive layer is formed include aluminum, aluminum alloy, copper, zinc, stainless steel,
vanadium, molybdenum, chromium, titanium, nickel,
Indium, gold, platinum, etc. are used. Plastics (e.g. polyethylene, polypropylene,
Polyvinyl chloride, polyethylene terephthalate, acrylic resin, etc.) or conductive particles (e.g. carbon black, silver particles, etc.) are coated on a plastic or metal substrate together with a suitable binder resin, or conductive particles are coated on a plastic or paper substrate. A support impregnated with the above-mentioned material can be used.

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

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

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

Another specific example of the present invention is an electrophotographic photoreceptor containing the above-mentioned trisazo pigment and charge transport material in the same layer. At this time, poly-N was used as a charge transport material.
- It is also possible to use charge transfer complexes consisting of vinylcarbazole and trinitrofluorenone.

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

The pigment used in any electrophotographic photoreceptor is a trisazo pigment represented by the general formula (1). The crystal form of the trisazo pigment may be amorphous or crystalline.
It is also possible to use a combination of two or more types of trisazo pigments shown in ) 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, CRT printers,
It can also be widely used in electrophotographic applications such as LED printers, liquid crystal printers, laser engravings, and facsimile printers.

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

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

In the figure, a drum type photoreceptor as an image carrier is rotated at a predetermined circumferential speed in the direction of the arrow around the shaft 1a. 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 exposed to a light image by an image exposure means (not shown) in the exposure section 3, such as slit exposure/laser. beam scanning exposure, etc.).

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

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

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

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

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

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

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

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

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

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

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

The entire controller 11 is controlled by a CPU 17.

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

The image received from the line 15 (image information from a remote terminal connected via the line) is demodulated by the receiving circuit 12, and then the CPL 117 performs signal processing on the image information and sequentially stores it in the image memory 16. . and at least 1
When the image of the page is stored in the memory 16, the image of the page is stored. CPU 17 is 1 from memory 16
Printer controller 18 reads page image information
1 page of image information signaled to is sent out.

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

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

As described above, images are received and recorded.

[Example 1 Examples 1 to 25 4.5 g of methoxymethylated nylon (weight average molecular weight 35,000) and 10 g of alcohol-soluble copolymerized nylon (weight average molecular weight 30,000) were placed on an aluminum substrate with 90 g of methanol.
Apply the solution dissolved in the above using a Mayer bar to form an undercoat layer with a thickness of 1 μm after drying.

Next, 5 g of Exemplary Pigment (1) was added to a solution prepared by dissolving 2 g of butyral resin (butyralization degree 70 mol %) in 90 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 would be 0.2 μm, and dried to form a charge generation layer.

Next, the styryl compound shown by the structural formula below and the log of polycarbonate type 2 resin (weight average molecular weight 60,000) were dissolved in 80 g of chlorobenzene, and this was poured onto the charge generation layer in a Mayer layer so that the film thickness after drying was 20 um. Apply with a bar,
It was dried to form a charge transport layer, and the electrophotographic photoreceptor of Example 1 was prepared.

Example 2 using other exemplary pigments in place of exemplary pigment (1)
Electrophotographic photoreceptors corresponding to Examples 1 to 25 were prepared in exactly the same manner.

The prepared electrophotographic photoreceptor was negatively charged with a corona discharge of 15 KV using an electrostatic copying paper tester Model 5P-428 manufactured by Kawaguchi Denki ■, held in a dark place for 1 second, and then charged with a halogen lamp. It was exposed to light at an illuminance of 1 flux, and the charging characteristics were evaluated.

The charging characteristics include the surface potential (V,) and the amount of exposure required to attenuate the surface potential by half (El/2) after being left in the dark.
was measured. Show the results.

l (1) 699 1.20
2 (2) 698 0.90
3 (3) 698 1.
304 (4) 697
0.95 (l 6) 25 (34) 700 0.91
Comparative Examples 1 to 5 Used in Example 1. Electrophotographic photoreceptors were prepared in exactly the same manner as in Example 1, except that the azo pigment was replaced with comparative pigments (A) to (E) represented by the following structural formulas, and the charging characteristics were evaluated in the same manner. Show the results.

Comparative Pigment (A) Comparative Pigment (B) Comparative Pigment (C) Comparative Pigment (D) Comparative Pigment (E) From these results, it can be seen that the electrophotographic photoreceptor of the present invention has sufficient charging ability and excellent sensitivity. .

Examples 26 to 50 The electrophotographic photoreceptor prepared in Example 1 was used in an electrophotographic copying machine equipped with a -6.5 KV corona charger, an exposure optical system, a developer, a transfer charger, a static elimination exposure optical system, and a cleaner. Attached to the cylinder.

The initial dark potential v0 and bright potential ■ are each -700
V, was set at around -200V, and the amount of variation in dark area potential (Δvt11) and the amount of variation in light area potential (ΔVL) were measured when the toilet was used repeatedly 5,000 times.

The electrophotographic photoreceptors prepared in Examples 2 to 25 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.

28 +2 -1+ 3 + ■ Ten = 7 +2 + 7 + 2 + 2 + + 3 Ten + 2 +3 + 5 + 2 + 3 + 2 + + 5 + + Comparative Examples 6 to 10 Created in Comparative Examples 1 to 5 The amount of potential fluctuation during repeated use of the electrophotographic photoreceptor was determined in the same manner as in Example 26 (7j1). Show the results.

6 * *7
-22 +738
-30 +209 *
*10 -53
+67* has poor sensitivity and a large residual potential, making it impossible to initialize. From the above results, it can be seen that the electrophotographic photoreceptor of the present invention has little potential variation during repeated use.

Example 51 A subbing layer of polyvinyl alcohol having a thickness of 0.5 um was formed on the aluminum surface of an aluminum vapor-deposited polyethylene terephthalate film. On top of this, the dispersion of the disazo pigment used in Example 2 was applied with a Mayer bar and dried, resulting in a film thickness of 0.2
A charge generation layer of .mu.m was formed.

Next, a solution prepared by dissolving 9 g of a fluorene compound having the following structural formula and 5 g of polycarbonate resin (weight average molecular weight: 35,000. did.

The charging characteristics and durability characteristics of the produced electrophotographic photoreceptor were measured by the same method as in Examples 1 and 26. Show the results.

v, knee 698V El/2: 0.89ffux-sec ΔVa knee IV ΔVL: +3V Example 52 Electrophotographic photosensitive material in which the charge generation layer and charge transport layer of the electrophotographic photoreceptor prepared in Example 5 were coated in the reverse order. create a body,
The charging characteristics were evaluated in the same manner as in Example 1. However, the charging was positive.

V,: +693V El/2: 1.05j2ux-sec Example 53 3.5 dimethyl-
3° 5°-di-tert-butyldiphenoquinone 5g
A solution prepared by dissolving 4 g of polycarbonate resin (weight average molecular weight 50,000) in 50 g of chlorobenzene (70 parts by weight)-N,N-dimethylformamide (30 parts by weight) solution was coated with a Mayer bar and dried to form a charge transport film with a thickness of 18 um. formed a layer.

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

V,: +698V El/2: 2.7I2ux-sec Example 54 05g of Exemplary Pigment (5) was dispersed with 9.5g of cyclohexanone in a paint shaker for 5 hours. A solution prepared by dissolving 5 g of the charge transport material used in Example 1 and 5 g of polycarbonate resin in 40 g of tetrahydrofuran was added to this.
Furthermore, it was shaken for 1 hour. The coating solution prepared in this way was applied onto an aluminum substrate using a Mayer bar and dried to a film thickness of 20 um.
A photosensitive layer was formed.

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

■.・+699■ El/2: 3.212 ux-sec [Effect of the invention 1 The electrophotographic photoreceptor of the present invention uses a trisazo pigment with a specific structure in the photosensitive layer, thereby increasing the efficiency of charge carrier generation inside the photosensitive layer. It has the remarkable effect of improving one or both of the injection efficiency and providing excellent characteristics in sensitivity and potential stability during repeated use.
Furthermore, similar excellent effects can be achieved when used in electrophotographic devices and facsimiles.

[Brief explanation of the drawing]

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

Claims (1)

[Scope of Claims] 1. An electrophotographic photoreceptor having a photosensitive layer on a conductive support, wherein the photosensitive layer contains a trisazo pigment represented by the following general formula (1). . General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (1) In the formula, Ar_1 and Ar_2 are the same or different and represent a carbocyclic aromatic group or a heterocyclic aromatic group which may have substituents, A_1 and A_2 are the same or different and represent coupler residues 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 trisazo 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 a receiving means for receiving image information from a remote terminal.