JPS61129650A - Laminate type electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To reduce variation of sensitivity and to improve durability by laminating on a conductive substrate an electrostatic charge transfer layer for positive hole transfer, and a charge generating layer contg. a charge transfer material represented by a specified chemical formula and a photoconductive azo pigment. CONSTITUTION:The laminate type electrophotographic sensitive body is prepared by laminating on the conductive substrate 5 the charge transfer layer 4 contg. a specified charge transfer material for transferring positive holes, and on this layer the charge generating layer 3, contg. the charge transfer material 2 represented by the formula in which (X is an optionally substd. heterocyclic group or anthryl group; Ar is optionally substd. aryl; and n is 0, 1, or 2), and the photoconductive azo pigment 1. The material 2 of the formula is dispersed together with the pigment 1 into a system composed of the binder resin and a soln. and the layer 4 is coated with this compsn. thus obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laminated electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor in which at least a charge transport layer and a charge generation layer are sequentially laminated on a conductive support.

2. Description of the Related Art Electrophotographic photoreceptors using inorganic photoconductors such as selenium, cadmium sulfide, and zinc oxide as photoreceptor components have been known.

On the other hand, many organic photoconductors have been developed since the discovery that certain organic compounds exhibit photoconductivity. low-molecular organic photoconductors such as carbonaceous polymers, carbazole, anthracene, pyrazolidines, oxadiazoles, human diacines, polyarylalkanes, phthalocyanine pigments, azo pigments, cyanine dyes, polycyclic quinone pigments, Organic pigments and dyes such as perylene pigments, indigo dyes, thioindigo dyes, and squaric acid methine dyes are known. Organic pigments and dyes that have photoconductivity in % are easier to synthesize than inorganic materials, and the variety of compounds that exhibit photoconductivity in the appropriate wavelength range has been expanded, so many photoconductive materials are used. Organic pigments and dyes have been proposed. For example, US Pat. No. 4,123,270, US Pat. No. 4,247,614, US Pat.
No. 56821, No. 4260672, No. 42685
96, No. 4278747, No. 4295628, etc. Electrophotography using an azo pigment exhibiting photoconductivity as a charge generation substance in a photosensitive layer functionally separated into a charge generation layer and a charge transport layer. Photoreceptors are known.

In its use, it has a structure in which a charge generation layer and a charge transport layer are laminated in this order on a conductive support, and the charge transport material used in the charge transport layer is a material with strong electron donating properties to transport positive charges. Generally, the photoreceptor was negatively charged.

Reasons for this include the fact that there are almost no materials with excellent negative charge transport properties, and that they are carcinogenic and cannot be used due to pollution concerns.

When negative corona discharge is performed, a large amount of ozone is generated, and an ozone filter must be installed on the copying machine itself, which increases costs. Also, as ozone filters gradually deteriorate over time, periodic maintenance such as filter replacement is required.

Furthermore, negative corona discharge tends to cause discharge unevenness due to dirt on the discharge wire, etc., which causes image unevenness. Furthermore, the generated ozone has a negative effect on the durability life of the OPO.

When negatively charged, there is a large ozone generation layer, and problems such as material deterioration on the surface of the photoconductor and adhesion of ionic substances generated (due to corona charging) to the photoconductor are noticeable, and these problems can occur locally or over the entire surface of the photoconductor. This causes a drop in potential, causing local or overall image blurring or image defects in copied images produced by electrophotography.

On the other hand, in a positive corona discharge, the amount of ozone generated is about 4 to 'Aa, and uneven discharge due to dirt on the discharge wire is less likely to occur, compared to a negative corona discharge. It is also very advantageous for the life of the photoreceptor. As described above, negative charging has many disadvantages, and there is an urgent need to develop photoreceptors with positive charging.

One way to create a positively charged laminated photoconductor is to
This can be achieved by sequentially laminating a charge transport layer having positive charge transport properties and a charge generation layer on a conductive substrate.

However, if the thickness of the charge generation layer is increased, the carriers originally generated are likely to be trapped in the charge generation layer, the optical memory becomes larger, and the bright area potential increases during repeated use. Normally 0.1 to I as the harmful effects are significant.
: It is customary to have an extremely thin film thickness of about L5μ.

However, when the charge generation layer is on the surface layer of the photoreceptor, charging, imaging light, development, transfer of the toner image to a transfer member such as paper or plastic film, separation of the transfer member from the photoreceptor, etc. Copying method Vc, such as removing static electricity before and after cleaning The current problem is that the sensitivity of the photoreceptor varies extremely rapidly, and in extreme cases, the charge generation layer is worn away and no longer exhibits sensitivity.

Problems to be Solved by the Invention The first object of the present invention is to provide a highly sensitive electrophotographic photoreceptor for positive charging in which at least a charge transport layer and a charge generation layer are successively laminated on a conductive support. be. A second object is to provide an electrophotographic photoreceptor for positive charging, which has improved electrophotographic properties and has at least a charge transport layer and a charge generation layer sequentially laminated on a conductive support.

The third purpose is to provide at least a charge transport layer on the conductive support.
An object of the present invention is to provide an electrophotographic photoreceptor for positive charging, which has improved durability and has charge generation layers laminated in sequence.

Means for Solving the Problems, Actions and Effects of the Invention The object of the present invention is to sequentially stack at least a charge transport layer having positive charge transportability and a charge generation layer on a conductive support, This is achieved by incorporating a photoconductive azo pigment and a specific positive charge transporting charge transport material.

The reason why a particular charge transporting material must be selected is to provide selectivity in the injection of carriers from the photoconductive azo pigment, which is the medium yellow generating material, to the charge transporting material in the charge generating layer. If an attempt is made to increase the physical strength of the photoreceptor surface by increasing the amount of binder resin in the charge generation layer, the transportability of carriers in the charge generation layer will be significantly reduced, leading to a decrease in sensitivity, deterioration of optical memory, and brightness during long-term use. This usually led to an increase in the potential of the parts.

However, by incorporating a specific charge transporting material with positive charge transportability into the charge generation layer, it is possible to ensure sufficient charge transportability within the charge generation layer even when the amount of binder is increased. became. Therefore, a photoreceptor with a strong physical strength on the surface of the photoreceptor and excellent sensitivity and optical memory can be obtained. Further, the object of the present invention is achieved, in that the abrasion of the photosensitive layer during long-term use is significantly reduced, and a photoreceptor with little change in sensitivity during long-term use is possible.

As the photoconductive azo pigment used in the present invention, an azo pigment having a phenolic OH group is used, and more specifically, an azo pigment represented by the general formula % (%) is particularly effective.

In the formula, 1 represents an integer of 2 or 3.

A is a divalent organic group in which carbon atoms to which an azo group is bonded form a conjugated double bond system, or 4)s.

Specific examples of divalent organic groups include: R2R4R,6R2H, -R2g is hydrogen, halogen such as chlorine, bromine, iodine, alkyl group such as methyl, ethyl, propyl, alkoxy group such as methoxy, ethoxy, propoxy, etc. group, benzyl,
Indicates an aralkyl group such as 7enethyl, a nitro group, a cyano group, etc.

R29 represents hydrogen, the above-mentioned alkyl groups, aralkyl groups, and aryl groups such as phenyl and naphthyl.

Specific examples of the organic group represented by 21h further include groups represented by the general formulas (1) to (8) above, each of which has a phenylazo group which may have a substituent at both ends.

m% n represents a 1i number of 0 or 1, and may be the same or different.

It is effective.

In general formula (10), Y represents a residue necessary for condensation with a benzene ring to form a polycyclic aromatic ring or heterocycle such as a naphthalene ring, anthr7ane ring, carbazole ring, benzcarbazole ring, dibenzofuran ring, etc. . -Sand formula (13),
(14) The middle 2 is a divalent group of aromatic membered water or N
Indicates a heterocyclic divalent group containing an atom in the ring.

Rsrr4s2 represents the alkyl group, aralkyl group, or aryl group represented by R1'429, and the 7lyl moiety in the % group is the alkyl group or alkoxy group represented by R1-R29.

It may be polysubstituted with a nitro group, a cyano group, a halogen group, an aralkyl group, an aryl group, or a #-substituted amino group such as dimethylamino, diethylamino, and dibenzylamino.

Specific examples of preferable azo pigments used in the present invention are shown below.

Exemplary Azo Pigment-1O A-16 A-17 Person-22 Person-23 Person-26 The charge transport material used in the charge generation layer of the present invention is represented by the following general formula % (%). In the formula, X is selected to have a substituent. X represents an alkyl group such as methyl, ethyl, propyl, etc., which may have a substituent, and Ar l represents an optional aryl group such as phenyl, naphthyl, anthryl, etc. Post.

Substituents for X and Ar include alkyl groups such as methyl, ethyl, and propyl, benzyl, aralkyl groups such as phenethyl, phenyl, naphthyl, and aryl groups such as anthryl.
Halogens such as chlorine, bromine, iodine, alkoxy groups such as methoxy, ethoxy, propoxy, dimethylamino, diethylamino, dipropylamino, ethylphenylamino, dibenzylaino, diphenylamino, morpholino,
Examples include substituted amino groups such as piperidino and pyrrolidino.

These substituents may be further substituted with other W groups.

town In the formula, n represents 0.1 or 2.

Next, specific examples of the compound represented by the general formula (1) used in the present invention will be shown.

Exemplary Compound The azo charge generating material used in the charge generating layer can be dispersed in a solution system of a suitable binder resin and a hydrazone charge transporting material, and then coated on the charge transporting layer prepared in advance to prevent stains. A charge generation layer can be formed.

The binder that can be used in forming the charge generating layer by coating can be selected from a wide variety of insulating resins, and can also be selected from organic photoconductive polymers such as poly+N-vinylcarbazole, polyvinylanthracene, and polyvinylpyrene.

Preferably, in addition to the photoconductive polymer, polyvinyl butyl, polyarylate (condensation polymer of bisphenol and heptalic acid, etc.), polycarbonate, polyester,
Examples of insulating resins include phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide resin, polyamide, urethane resin, and epoxy resin.

The resin contained in the charge generating layer is preferably 10 to 80% by weight, and preferably 50 to 60% by weight from the viewpoint of physical strength of the photoreceptor surface and medium transportability within the charge generating layer.
It is desirable to do so.

The proportion of the charge transporting material contained in the charge generation layer is preferably 10 to 70% by weight for the same reason as the resin amount, and more preferably 20 to 60% by weight.

The proportion of the charge generating material contained in the charge generating layer is preferably 0.3 to 80%.

The solvent used in the paint for the charge generation layer depends on the resin used,
The material is selected based on the solubility of the charge transport material and the dispersion stability of the charge generation material, but it is also necessary to select materials that dissolve the lower charge transport layer and subbing layer.

Specific organic solvents include alcohols such as methanol, ethanol, and isopropanol, acetone, and MF:
Amides such as cyclohexanone, N,N-dimethylformamide, N,N-') methylacetamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydro7rane, dioxane, ethylene glycol 7methyl ether, methyl acetate, Esters such as ethyl acetate, aliphatic/logenated hydrocarbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, trichlorethylene, benzene, toluene, xylene, ligroin, monochlorobenzene,
Aromatics such as dichlorobenzene can be used.

Coating methods include dip coating, spray coating, spinner coating, bead coating,
This can be carried out using a coating method such as a Mayer bar coating method, a blade coating method, a roller coating method, or a curtain coating method. For drying, a method of drying to the touch at room temperature and then heating drying is preferred. Heat drying can be carried out at a temperature of 30 to 200° C. for a period of time ranging from 5 minutes to 2 hours, either stationary or under ventilation.

The charge transport layer is electrically connected to the charge generation layer described above, and the 'FL' injected from the charge generation layer in the presence of an electric field is
It has the function of receiving and taking charge carriers and transporting these charge carriers to the surface of the conductive support or to the surface of the subbing layer interposed between the 4'tf@ and the charge transport layer.

For the charge transport layer, a positive charge transporting material is used.

Examples of hole-importing substances include pyrene, N-ethylcarbazole, N-impropylcarbazole, and N-methyl-N
-Phenylhydrazino-3-methylidene-9-ethylcarbazole, N,N-diphenylhydrazino-3-methylidene-9-ethylcarbazole, N,N-diphenylhydrazino-3-methylidene-1o-ethylphenothiazine, N , N-diphenylhydrazino-3-methylthene-10-ditylphenoxacin, p-diethylamino(nzaldehyde N, N-diphenylhyh',
y Son, PI ethylaminobenzaltehyde N-α
-Naphthyl-N-phenylhydrazone, P-pyrrolidinobenzaldehyde-N, N-diphenylhydrazone,
1,3.3-trimethylindolenine-ω-aldehyde-N,N-diphenylhydrazino, P-diethylbenzaldehyde-6-methylbenzthiazolinone-2-
Hydrazones such as hydrazone, 2,5-bis(P-diethylaminophenyl)-1,3,4-oxadiazo-
/l/, 1-phenyl-5-<P-)ethylaminostyryl)-5-(P-diethylamino7enyl)pyrazoline, 1-[quinolyl(2))-3-(p-diethylaminostyryl)- 5-CP-uethylaminophenyl)pyrazoline, 1-[pyridyl (2) J-3-(P-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, 1-(6-medoxypyridyl
21) -3-(P-diethylaminosteryl)-5-
(P-diethylaminophenyl)pyrazoline, 1-[pyridyl(3))-3-CP-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, 1-(lepidyl(2))-3-(P-diethylamino steryl)-5-(P-diethylaminophenyl)pyrazoline, 1-[pyridyl(2))-3-(P
-',; ethylaminostyryl)-4-methyl-5-
(P-diethylaminophenyl)pyrazoline, 1-[pyridyl(21)-5-(α-methyl-P-diethylaminostyryl)-5-(P-diethylaminophenyl)
Pyrazoline, 1-phenyl-3-(P-diethylaminostyryl)-4-methyl-5-(P-uethylaminophenyl)pi9purine, 1-phenyl-3-(α-benzyl-P-diethylaminostyryl)- Pyrazolines such as 5-CP-diethylaminophenyl) pyrazoline and spiropyrazoline, 2- (P-'; ethyl 7 minosti!
J)-6-dinithylaminobenzoxazole, 2-
Oxazole compounds such as (P-';ethylaminophenyl)-4-CP-dimethylaminophenyl)-5-(2-'lorophenyl)oxazole, 2-(P-diethylaminostyryl)-6-:) ethylaminobenzo Thiazole compounds such as theazole, nodriarylmethane compounds such as bis(4-diethylamino-2-methylphenyl)-phenylmethane, 1,1-bis(4-N,N
-', ;ethylamino-2-methylphenyl)heptane, polyarylalkane such as 1,1,2.2-tetrakis(4-N,N-dimethylamine-2-methylphenyl)ethane, triphenylamine, poly- N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinylacridine, )? 'J-9-vinylphenylanthracene, pyrene-formaldehyde resin, ethylcarbazole formaldehyde resin, etc.

In addition to these mi-carrying substances, inorganic materials such as selenium, selenium-tellurium amorphous silicon, and cadmium sulfide can also be used.

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

When the charge transport material does not have film-forming properties, a film can be formed by selecting an appropriate binder. Resins that can be used as binders include acrylic resin,
Insulating resins such as polyarylate, polyester, polycarbonate, polystyrene acrylonitrile-styrene copolymer, acrylonitrile-butadiene copolymer, polyvinyl fluoride, rt'lihynyl formal, polysulfone, polyacrylamide, polyamide, chlorinated rubber, or -N-vinylcarbazole,
Mention may be made of organic photoconductive polymers such as polyvinylanthracene and polyvinylpyrene.

Since the charge transport layer has a limit in its ability to transport charge carriers, it cannot be made thicker than necessary. Generally, it is 5 to 30μ, but the preferred range is 8S20μ
It is. When forming the charge transport layer by coating, an appropriate coating method as described above can be used.

A photosensitive layer having such a laminated structure of a charge generation layer and a charge transport layer is provided on a substrate having a conductive layer. As the substrate having a conductive layer, the substrate itself has tetraconductivity,
For example, aluminum, aluminum alloy, steel, zinc, stainless steel, vanadium, molybdenum, chromium, titanium,
In addition to nickel, indium, gold, and white metals, aluminum, aluminum alloys, indium oxide, tin oxide, and indium-tin oxide alloys can be used as a layer formed by vacuum evaporation. conductive particles (e.g. carbon black, silver particles, etc.) coated on the plastic with a suitable binder. As a substrate, a substrate made of plastic or paper impregnated with 24-electrode particles, a plastic containing a 4'yIL polymer, etc. can be used.

A subbing layer having barrier and adhesive functions can also be provided between the layer and the charge transport layer.

The undercoat layer is made of casein, polyvinyl alcohol, nitrocellulose, ethylene-7) kR-14 reamer, polyamide (nylon 6, nylon 66, nylon 6-1).
0. It can be formed from copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, gelatin aluminum oxide, etc.

The thickness of the undercoat layer is 0.1 to 5μ, and the favorable IL< is 0.5 to 6.
μ is appropriate.

The electrophotographic photoreceptor used in the present invention may be contaminated by ultraviolet rays, oil deteriorated by ozone, etc., hot water may be caused by cutting powder of metal, etc., and the photoreceptor may be damaged by photoreceptor abutting members such as developing members, transfer members, and cleaning members. A protective layer may be further provided on the charge generation layer for the purpose of preventing scratches and scraping. In order to form an electrostatic latent image on this storage layer, the surface resistivity must be 10.
It is desirable that the resistance is 11Ω or more.

The protective layer used in the invention may include resins such as polyvinyl butyral, polyester, polycarbonate, acrylic resin, methacrylic resin, nylon, polyimide, polyarylate, polyurethane, styrene-butadiene copolymer, styrene-acrylic copolymer, and styrene-acrylonitrile copolymer. The resin solution can be formed by applying a solution dissolved in an appropriate organic solvent onto the photosensitive layer and drying it. Additives such as an ultraviolet absorber can also be added to the resin solution. At this time, the thickness of the protective layer is generally 0.05 to 2
0μ, particularly preferably in the range of 0.2 to 5μ.

The layer structure of the electrophotographic photoreceptor of the present invention is shown in FIGS. 1 to 4.

When using a photoreceptor in which a conductive layer, a charge transport layer, and a charge generation layer are laminated in this order, the charge transport material consists of a hole transport material, so it is necessary to apply a positive KW charge to the surface of the charge generation layer. Upon exposure, holes U generated in the charge generation m are injected into the charge transport layer in the exposed portion. On the other hand, electrons generated in the absence of light reach the surface and neutralize the positive charges, resulting in attenuation of the surface potential and electrostatic contrast between the surface potential and the unbound portion. A visible image can be obtained by developing the electrostatic image thus formed with a negatively charged toner. Fix this directly or
Alternatively, the toner image can be visually imaged and fixed after being transferred to paper, stick film, or the like.

Alternatively, a method may be used in which the latent image '1 on the photoreceptor is transferred onto an insulating layer of transfer paper, then developed and fixed. The type of developer, the developing method, and the fixing method may be any known ones or known methods, and are not limited to specific ones.

The electrophotographic photoreceptor of the present invention can be used not only in electrophotographic copying machines, but also in a wide range of electrophotographic applications such as laser printers and ORr printers.

The present invention will be explained below according to examples.

Examples 1 to 14 Ammonia aqueous solution of casein (casein 1
t29.28% ammonia water 1), water 222mQ)
It was applied and dried using a tl-Meyer bar so that the film thickness after drying was 1.0 μm. Next, 5j1 of the charge transport material B-1 exemplified above and 5jl of polymethyl methacrylate (number average molecular weight 100,000) were dissolved in 7Qm (l) of benzene,
This was coated on the undercoat layer using a Mayer bar so that the film thickness after drying was 12μ, dried, and the charge transport/l1t-
Formed.

Next, exemplified azo preparation A-1 was added to a solution obtained by dissolving 45 ml of exemplified cargo transport material B-1 and 459 ml of polymethyl methacrylate (number average molecular weight: 100,000 ml) in 800 ml of chlorobenzene.
10jl of the mixture was added and dispersed in a sand mill for 10 hours. The electrophotographic photoreceptor of Example 1 was prepared by first forming this dispersion, coating it on a fci [packing pigeon] using dip-coated paper, and drying to form a charge generation layer with a thickness of 5 μm. Apart from the photoreceptor of Example 1, exemplified compounds B-2 to B- used in the charge generation layer
Example 2 was carried out in exactly the same manner as in Example 1 except that 14 was replaced.
~14 photoreceptors were made.

The electrophotographic photoreceptor thus prepared was subjected to static corona testing at +5 KV using a Kawaguchi Den@@Risei Den Copying Paper Tester Modem 5P-428, and after being held in a dark place for 1 second, the illuminance was 5KV. We formed a group using J'UX and investigated the fluorescent conductivity.

The charging characteristics include the surface potential (VO) and the amount of cohesion necessary to dramatically reduce the potential when darkened for 1 second (Jlt+/
2) k was measured. The results are shown in Table 1.

Table 1 1 B-15804,0 2B-25904,4 3B-36104,3 4B-45704,2 5B-55804,5 6B-66005,3- 7B-75803,6 8B-86103,8 9B-95904,0 10B-105704,6 11B-115904,3 12B-126104,5.

13B-136004,0, 14B-145904,0 As shown in the table, the photoreceptor of the present invention exhibited good positive chargeability and positive chargeability.

Comparative Example 1 A photoreceptor was prepared in exactly the same manner as in Example 1 except that the B-1 compound was not used in the charge generation layer of Example 1, and its characteristics were investigated. Surface potential +580, L'/2161 Lux,
sea), the original E! Extremely low M&
Too bad, it has no practical use at all.

Examples 15 to 25 A polyvinyl alcohol film having a thickness of 1.1 μm was formed on the aluminum surface of an aluminum vapor-deposited polyethylene terephthalate film by dip coating.

Next, the photoreceptors of Examples 15 to 25 were prepared in exactly the same manner as in Example 1, using materials shown in Table 2 below in place of the charge transport materials and charge generation materials used in the charge transport layer and charge generation layer of Example 1. It was created and the potential was measured. The results are shown in Table 3. Optical memory has been added as a potential measurement item. By exposing the photoreceptor to light before charging, the charging potential of a photoreceptor with a strong optical memory will drop significantly, causing an extreme drop in image density or white spots in the front embossed area. As a method for evaluating the optical memory, pre-exposure for 6QQAuc 3 minutes is given, and the difference in surface potential (Δv4) is expressed as a decrease in surface potential compared to when no pre-exposure was performed.

Upper table fist 16 Same as above Same as above B-
217 Same as above Same as above B-319
Same as above Same as above B-52OA-1
1B-7 21 Same as above Same as above B-824 Exemplary compound B-3A-22B-1325 Same as above A-2
6B-14 1,3 table number 15 610 4.2
2016 570
3.8 2517 59
0 5.7 20
18 580 5.9
1019 600
3.8 2020 61
0 4.0 20
21 580 5.4
2022 570
4.2 3023 58
0 3.8 2
024 600 4.0
2525 10
4.4 20 Comparative Examples 2-5 Implementation? Comparative photosensitivity was carried out in exactly the same manner as in Example 15.20.2.5.24, except that the charge transport material shown in Table 4 was used in place of the charge transport material in the charge generation layer of lJ 15.20.23.24. Body 2 to 5 were created. The results of the potential measurement are shown in Figure 5.

Table 4 Comparative Example Charge Transport Material 2H5 Used in Charge Transport J- Table 5 2 590 1.6 130 When the charge transport material of the charge generation layer is replaced with a material different from the material of the present invention, the sensitivity, optical mesometry However, the system using a photoconductive azo pigment in combination with the charge transport material included in the present invention in the charge generating layer of the present invention was proved to be extremely effective.

Example 26 An aluminum cylinder with a diameter of 60 mm was coated with the same coating solution as in Example 1 except that the binder resin used for the charge generation layer was replaced with polycarbonate resin (number average molecular weight 75,000) K, and the immersion method was used. Each layer was sequentially laminated to prepare an electrophotographic photoreceptor.

PPC copier for positive charging made by Canon@ (prototype)
1-, the initial dark area potential was set to i + 700v, and the initial light area potential was set to 't-100v, and 10,000 images were printed using negatively charged toner, and the potential was measured after the durability was left for one night.

The drum rotor of the test prototype is equipped with a positive charging corona charger, a condensation section, a developing section, a positive charging corona charger for transfer, a blade cleaner, and a pre-exposure lamp.

The results of potential measurement are initial durability potential (+V) dark area potential after 10,000 sheets of durability (+V) 700 720 four part potential
100 to 120 The sensitivity fluctuation due to image printing was small, and there was no blurring or image defects due to ozone deterioration, and no discharge mark 2 due to corona wire contamination was observed, and a beautiful image was obtained even after 10,000 prints.

Example 27 A methanol solution of polyvinyl butyral resin (saponification degree 100, butyralization degree 75, number average molecular weight t30,000) was applied by dipping onto a photoreceptor prepared in exactly the same manner as in Example 26. After drying, a protective layer with a thickness of 3 μm was completely formed.

Using this photoreceptor and using the same equipment as in Example 26, image printing durability was carried out in exactly the same manner as in Example 26, and good results were obtained as in Example 2°6.

Effects of the Invention The present invention provides a photoreceptor in which a photoconductive azo pigment and a charge transport material represented by the general formula (1) are added to the charge generation layer of a photoreceptor in which at least a charge transport layer and a charge generation layer are sequentially laminated on a conductive support. Its use brings about the following remarkable effects.

1) The charge generation layer can be made thicker because the carrier transportability within the charge generation layer is improved, and sensitivity fluctuations due to abrasion of the charge generation layer during long-term use can be reduced. 2) Similar characteristics For some reason, it is possible to lower the pigment/binder resin ratio of the charge generation layer 121 and increase the binder resin content, which results in increased physical strength of the surface of the charge generation layer and improved durability. 3) Since the carrier transportability inside the charge generation layer is improved, the photogenerated carriers are trapped inside the charge generation layer and K<<, resulting in improvements in sensitivity, optical memory, and residual potential. 4) The carrier injection from the charge generation layer to the charge transport layer is smooth, and the same effects as in 3) can be obtained.

[Brief explanation of drawings]

1 to 4 show the layer structure of the electrophotographic photoreceptor of the present invention. Reference numeral 1 is a photoconductive azo pigment, 2 is a binder resin and a charge transport material represented by the general formula (1), 3 is a charge generation layer, 4 is a charge transport layer, 5 is a conductive support, and 6 is an undercoat layer. , 7 represents a protective layer or an insulating layer.

Claims (2)

[Claims] (1) At least a hole-transporting charge transport layer and a charge generation layer are sequentially laminated on a conductive support, and the charge generation layer contains a photoconductive azo pigment and a charge transport material represented by the following general formula (I). A laminated electrophotographic photoreceptor characterized by containing. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) However, in the formula, X represents a heterocyclic group or anthryl group that may have a substituent, and Ar represents an aryl group that may have a substituent. show. n represents an integer of 0, 1 or 2. (2) The photoconductive azo pigment used in the charge generation layer has the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (II), and X in the general formula (I) described in claim 1 represents Heterocyclic groups have ▲mathematical formulas, chemical formulas, tables, etc.▼, ▲mathematical formulas, chemical formulas,
There are tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼
, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ▲ There are mathematical formulas, chemical formulas, tables, etc. A divalent organic group or ▲ formula in which carbon atoms form a conjugated double bond system,
There are chemical formulas, tables, etc.▼ where B represents a coupler having a phenolic OH group, l is an integer of 2 or 3, and Y in the heterocyclic group represented by X above represents 0, S or Se. ,
The electrophotographic photoreceptor according to claim 1, wherein R represents an alkyl group.