JPS59231545A - Photosensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body having very long use life and continuous use life by incorporating a specified compd. in a carrier transfer phase and an electron receptor in at least one of the carrier transfer phase or a carrier generating phase. CONSTITUTION:A carrier transfer phase contains a hydrazone type compd., such as a compd. of formula II or III, represented by general formula I in which R<1> is optionally substd. naphthyl; R<2> is optionally substd. alkyl, aralkyl, or aryl; R<3> is H, alkyl, or alkoxy; and R<4>, R<5> are each optionally substd. alkyl, aralkyl, or aryl. It also contains an electron receptor, such as tetrachlorophthalic anhydride in the carrier transfer phase and/or a carrier generating phase. The photosensitive body thus obtained has little electric fatigue, a very long use life, and especially long continuous use life, and it can be extremely lowered in the residual potential of the photosensitive layer. As a result, continuous copying can be made in many times without any restoration operation, and the photosensitive layer is stable against oxidation and said body is high in mechanical strength.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Industrial Application Field The present invention relates to a photoreceptor, particularly an electrophotographic photoreceptor, having a carrier generation phase and a carrier transport layer.

2. Prior Art In recent years, in the field of electrophotography technology, a carrier generation layer containing a substance that absorbs visible light and generates charge carriers,
It has been proposed that the photosensitive layer of the Shimiko photographic photoreceptor be constructed by combining the photosensitive layer with a carrier transport layer that transports either or both of the positively and negatively charged carriers generated in the carrier generation layer. In this way, by assigning the two basic functions in the photosensitive layer of generating charge carriers and transporting them to separate substances or material systems,
The range of materials that can be used to construct the photosensitive layer is widened. In addition, it is possible to independently select materials or material systems that optimally perform each function, and this also makes it possible to meet the characteristics required in the electrophotographic process, such as the surface potential when charged. It becomes possible to construct a photosensitive layer having excellent characteristics such as high density, high charge retention, high surface strength, high photosensitivity, and high stability in repeated use.

Conventionally, as such a photosensitive layer, the following ones are known, for example.

(1) Laminated carrier generation layer made of amorphous selenium or cadmium sulfide and carrier transport layer made of poly-N-vinylcarbazole (2) Carrier generation layer made of amorphous selenium or cadmium sulfide layer and 2,
4.7-) Laminated with a carrier transport layer containing dinitro-9-fluorenone.

(3) A layer in which a carrier generation layer made of a perylene derivative and a carrier transport layer containing an oxadiazole rust conductor are laminated (see US Pat. No. 3,871,882) (4) Chlordiayan blue or methyl sulfate A layer in which a carrier generation layer composed of lyllium and a carrier transport layer containing a pyrazoline derivative are laminated (JP-A-51-9
(See Publication No. 0827).

(5) A layer in which a carrier generation layer composed of amorphous selenium or its alloy and a carrier transport layer containing a polyarylalkane aromatic amine compound are laminated (Patent application No. 52
-147251 specification).

(6) A layer in which a carrier generation layer containing a perylene derivative and a carrier transport layer containing a polyarylalkane aromatic amine compound are laminated (% Hara Sho 53-199
07 Specification).

As described above, many types of photosensitive layers are known, but in many conventional electrophotographic photoreceptors having such photosensitive layers, the electricity of the photosensitive layer increases when repeatedly subjected to electrophotographic processes. It has the disadvantage of severe mechanical fatigue and a very short service life. That is, although it is necessary to eliminate the charge in the photosensitive layer when one electrophotographic process is completed and the photosensitive layer is used for the next electrophotographic process, in this type of photosensitive layer, the discharge rate at the final stage of discharge is low. Because the charge is extremely small, it is impossible to completely remove the charge even if the charge is removed by exposure to a large amount of light, and a very high residual potential remains. Eventually, after a small number of continuous copies, the residual potential exceeds its permissible limit and becomes unusable as an electrophotographic photoreceptor.

Although it is possible to restore some types of photoreceptors to a usable state, the recovery is short-lived and requires leaving the photoreceptor in a dormant state for a long period of time, or applying appropriate heat treatment. However, the residual potential cannot be restored to a sufficiently lowered state, and therefore, the number of consecutive copies that can be made before the next unusable state is reached is greatly reduced.

For example, in an electrophotographic photoreceptor that uses a carrier transport material with electron donating properties and combines this with a carrier generation material, a trace amount of A method has been proposed in which a Lewis acid is added into the layer containing the carrier transport material.

However, although this method is effective for photoreceptors using a specific electron-donating carrier transport material, it is effective for photoreceptors using many other electron-donating carrier transport materials.
This is not effective in preventing the accumulation of a sufficient residual potential. In particular, photoreceptors using carrier transport materials such as polyarylalkane-based aromatic amino compounds are subject to significant deterioration due to UV rays, etc.
'The reality is that I can only do four things.

3. Object of the Invention The object of the present invention is to have a very long service life with almost no electrical fatigue, and a particularly long continuous service life, and to reduce the residual potential of the photosensitive layer to practically no level by eliminating static electricity. The photosensitive layer has an extremely low level of oxidation activity caused by light, temperature, and corona discharge, and can be continuously copied many times without any trouble. The object of the present invention is to provide a photoreceptor that is stable to species, has high mechanical strength, and can perform its functions stably over a long period of time in these respects as well.

4. Structure and effects of the invention, that is, the present invention provides a photoreceptor having a carrier generation phase and a carrier transport layer, in which a hydrazone compound represented by the following general formula is contained in the carrier transport layer, and the carrier transport layer has an electron-accepting property. The present invention relates to a photoreceptor characterized in that a substance is contained in at least one of the carrier transport layer and the carrier generation phase.

General formula: (However, R1 is a substituted or unsubstituted 7-tyl group; R2 is a substituted or unsubstituted alkyl group (e.g. methyl group, ethyl group, propyl group, butyl group, hexyl group), aralkyl group (e.g. benzyl group) R3 is a hydrogen atom, an alkyl group (same as above) or an alkoxy group (such as a methoxy group, ethoxy group, butoxy group)
; R4 and R5 are the same or different groups consisting of a substituted or unsubstituted alkyl group (same as above), aralkyl group (same as above) or aryl group (same as above);

In the case of the above-mentioned substituted groups, the substituent is, for example, an alkyl group such as a methyl group, ethyl group, propyl group, butyl group,
Alkoxy groups such as methoxy, ethoxy, propoxy and butoxy groups; halogen atoms such as chlorine, bromine and iodine; dimethylamine and diethylamino groups;
Examples include dialkylamino groups such as dipropylamino and dibutylamino groups. ) The above hydrazone compound according to the present invention has a photocarrier (
In particular, when a photoreceptor is constructed by laminating a conductive support, a carrier generation layer, and a carrier transport layer in this order, the surface of the photoreceptor is particularly negatively charged and exposed to light. Holes generated in the generation layer are injected into the carrier transport layer and then efficiently transported to the surface, and by selectively neutralizing surface charges, it is possible to form an electrostatic charge image with good contrast with unexposed areas. As described above, although the above-mentioned hydrazone compound has excellent performance, it has been found that the following problems occur when used alone.

However, the above-mentioned hydrazone compound is easily decomposed and deteriorated by the action of ultraviolet light or ozone heat, resulting in an increase in residual potential when the photoreceptor is used repeatedly.

The cause of this is not clear at present, but it may be that the -CH=N- double bond in the molecule is decomposed by ultraviolet light, etc., and becomes a different substance or becomes a radical state. This is thought to act as a pore trap and cause an increase in residual potential. Therefore, according to the present invention, the above electron-accepting substance is contained in the carrier transport layer and/or the carrier generation phase. Therefore, the amount of change in residual potential during repeated use can be greatly reduced. This is because the electron-accepting substance and the hydrazone compound in the carrier transport phase form a charge-transfer complex, and upon irradiation with light, this charge-transfer complex efficiently generates photocarriers, which are then trapped as described above. It is thought that the charge transfer complex is more stable against harmful light than the hydrazone compound alone, possibly because it recombines holes.

In addition, in the present invention, the "phase" of the carrier generation phase and the carrier transport layer means not only the case where each layer forms, but also the case where the respective substances are mixed to form 7 aids. .

5. Examples Hereinafter, the present invention will be described in detail with reference to examples.

First, specific examples of the hydrazone compound and electron-accepting substance used in the present invention will be explained.

Examples of hydrazone compounds include the following.

(I-1) (I-5) (I-6) (I-9) (I-11) (I-12) (I-13) (I-14) CI-15) (I-16) (I-17) C2H,t4n,.

″ -18) -19) (I-20) (I-21) 2US The hydrazone compound represented by this general formula has the general formula: H2N -N -R1 2 (However, R1 and R2 are the same as those described above. ) and an aldehyde represented by 'R3, R4, and R5 are the same as those described above.

Examples of the electron-accepting substance to be contained in at least one of the carrier generation phase and the carrier transport layer include succinic anhydride, maleic anhydride, dibromaleic anhydride, phthalic anhydride, tetrachlorophthalic anhydride, and tetrabromophthalic anhydride. , 3-nitrophthalic anhydride, 4-nitrophthalic anhydride, pyromellitic anhydride, mellitic anhydride, tetracyanoethylene, tetracyanoquinodimethane,
o-dinitrobenzene, m-dinitrobenzene, t, a
, 5)! j Nitrobenzene, paranitrobenzonitrile, vicryl chloride, quinone chlorimide, chloranil, fromanil, dichlorodicyanoparabenzoquinone, anthraquinone, dinitroanthraquinone, 2,7
-Sinitrofluorene, 2, 417-)! J nitrofluorenone, 2.4,5.7-teto2nitrofluorenone, 9-fluorenylidene [dicyanomethylenemalonodinitrile], polynitro-9-fluorenyritene [dicyanomethylenemalonodinitrile], picric acid,
0-nitrobenzoic acid, p-nitrobenzoic acid, 3.5-dinitrobenzoic acid, pentafluorobenzoic acid, 5-nitrosalicylic acid, 3,5-dinitrosalicylic acid, phthalic acid,
Examples include mellitic acid and other compounds with large electron affinities. Among these electron-accepting substances, especially tetratran
Preferred are chlorophthalic anhydride, tetrabromo-heptadalic anhydride, picrylic chloride, 2,4,7-dolinitrofluorenone, or 3,5-dinitrobenzoic acid, and when these are used, electrical deterioration is reduced, etc. The effect can be made even greater.

Next, the mechanical structure of the electrophotographic photoreceptor of the present invention will be explained.

In one example of the present invention, as shown in FIG.
The CTL 3 containing TM as a main component is formed by laminating them, and the CGL 2 and CTL 3 constitute a photosensitive layer 4.

Next, the present invention will be specifically explained with reference to the drawings.

The photoreceptor of the present invention is constructed as shown in FIG. 1, for example. That is, a carrier generation layer 2 containing a carrier generation substance described later as a main component is formed on a conductive support l, and a carrier transport layer 3 containing the above-mentioned carrier transport substance as a main component is formed on this carrier generation layer 2. are laminated to form a carrier generation layer 2, a carrier transport layer 3, and a photosensitive layer 4.

Here, as the material of the conductive support 1, for example, a sheet of metal such as aluminum, nickel, copper, zinc, palladium, silver, indium, tin, platinum, gold, stainless steel, brass, etc. can be used. The present invention is not limited to these, and for example, as shown in FIG. 2, a conductive layer IB may be provided on an insulating substrate IA to constitute the conductive support 1. In this case, the substrate IA is paper,
2) A material such as a plastic sheet that is flexible and has sufficient strength against stress such as bending and tensile stress is suitable. The conductive layer IB can also be provided by laminating metal sheets, vacuum depositing metal, or by other methods.

The carrier generation layer 2 may be made of a carrier generation substance alone, which will be described later, or an appropriate binder resin added thereto, or a substance with high mobility for carriers of a specific or non-specific polarity (i.e., a carrier generation substance). It can be formed by adding a transport substance).

The specific formation method includes vacuum-depositing a carrier-generating substance on the support, and applying a solution or dispersion of the carrier-generating substance in an appropriate solvent and drying it.
Examples of methods include drying.

In this latter method, binder resins or carrier transport substances may be added, in which case
The ratio of carrier generating substance: binder resin: carrier transporting substance is 1: (0 to 100): (0 to 500) by weight.
), particularly preferably 1:(θ~10):(θ~50).

As the carrier-generating substance, inorganic pigments and organic pigments can be used as long as they absorb visible light and generate free carriers. In addition to inorganic pigments such as amorphous selenium, trigonal selenium, selenium-arsenic alloy, selenium-tellurium alloy, cadmium sulfide, cadmium selenide, cadmium selenide sulfide, mercury sulfide, lead oxide, lead sulfide, the following representative examples Organic dyes such as those shown in may also be used.

(1) Azo dyes such as monoazo dyes, polyazo dyes, metal complex azo dyes, pyrazolone azo dyes, stilbene azo dyes, and thiazole azo dyes (2) Perylene dyes such as perylenic anhydride and perylenic acid imide (3) Anthraquinone derivatives, anthrone derivatives, dibenzpyrenequinone derivatives, vilantrone derivatives,
Anthraquinone to polycyclic quinone dyes such as violanthrone derivatives and isoviolanthrone derivatives (4) Indigoid dyes such as indigo derivatives and thioindigo derivatives +51 7-thalocyanine dyes such as gold M phthalocyanine and metal-free phthalocyanine (6) Diphenylmethane dyes , carbonium dyes such as triphenylmethane dyes, xanthine dyes and acridine dyes (7) Quinoneimine dyes such as azine dyes, oxazine dyes and thiazine dyes (8) Methine dyes such as cyanine dyes and azomethine dyes (9) Quinoline dyes Dyes: Nitro dyes 01 Nitroso dyes α2 Benzoquinone and naphthoquinone dyes (131 Naphthalimide dyes - α group of perinone dyes such as bisbenzimidazole derivatives Quinacridone dyes Among these organic dyes, azo pigments are particularly suitable for the present invention. It is preferable because it bonds well with the hydrazone compound used as a charge transport material in the process and provides high sensitivity.

Examples of binder resins used here include polyethylene, polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, and silicone resin. , addition polymer resins such as melamine resins, polyaddition resins, polycondensation resins, and copolymer resins containing two or more of the repeating units of these resins, such as vinyl chloride-vinyl acetate! ! Examples of the polymer 41 include resins, vinyl chloride-vinyl acetate-maleic anhydride copolymer resins, and polymeric organic semiconductors such as poly-N-vinylcarbazole. However, the binder resin is not limited to these, and all resins commonly used for darning purposes can be used.

As the carrier transporting substance having high mobility for carriers of specific or non-specific polarity that can be added to the carrier generation layer, a carrier transporting substance used in the construction of the carrier transporting layer 3 etc. can be used, but electrophotographic photosensitive Other carrier transport materials may be used in consideration of physical performance.

Furthermore, one or more electron-accepting substances can be contained in the carrier-generating layer for the purpose of improving sensitivity, reducing residual potential or fatigue during repeated use, and the like.

The ratio by weight of the electron-accepting substance is carrier-generating substance:electron-accepting substance=100:0.01-100, preferably 100:0.1-50.

If the electron-accepting substance is less than 0.01 parts by weight, the image background potential (white paper potential) increases significantly, and if it exceeds 100 parts by weight, the image potential (black paper potential) decreases significantly, and stable repeatability is not obtained in either case. The thickness of the carrier generation layer 2 formed in such a manner that the thickness is less than 0 is preferably 0.005.
~20 μm, particularly preferably 0.1 to 5 μm. 0
．． If it is less than 0.005 μm, it is difficult to obtain sufficient photosensitivity, and if it exceeds 20 μm, it is difficult to obtain sufficient charge retention.

The carrier transport layer 3 is formed by applying a coating solution obtained by dissolving or dispersing the above-mentioned hydrazone-based compound as a carrier transport substance in a suitable solvent 1 together with a suitable binder resin if necessary, and then drying. It can be formed by other methods.

Examples of binder resins that can be incorporated into the charge transport layer in the present invention include polyethylene, polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, Addition polymer resins such as alkyd resins, polycarbonate resins, silicone resins, and melamine resins, polyaddition resins, polycondensation resins, and copolymer resins containing two or more repeating units of these resins, such as vinyl chloride. In addition to insulating resins such as -vinyl acetate copolymer resin and vinyl chloride-vinyl acetate-maleic anhydride copolymer resin, polymeric organic semiconductors such as polyJ-N-vinylcarbazole can be mentioned.

In the present invention, the content ratio of the binder resin and the hydrazone compound used in the charge transport layer is
The amount of the hydrazone compound is 20 to 400 parts by weight, preferably 50 to 200 parts by weight. 2
If it is less than 0 parts by weight, it is difficult to obtain sufficient photosensitivity;
If it exceeds 0 parts by weight, the film strength of the charge transport layer will be significantly reduced.

In the present invention, the charge transport layer has improved sensitivity,
'The electron-accepting substance may be contained for the purpose of reducing residual potential and fatigue during repeated use.

In this case, the content ratio of the electron accepting substance is 0.001 to 10 parts by weight, preferably 0.01 to 5 parts by weight, per 100 parts by weight of the charge transporting substance. The thickness of the charge transport layer 3 thus formed is 2 to 100 μm, preferably 5 to 30 μm. If it is less than 2 .mu.m, it is difficult to obtain a sufficient acceptance potential for image formation, and if it exceeds 100 .mu.m, it is difficult to obtain sufficient sensitivity because the electric field strength applied to the photosensitive layer decreases.

The electrophotographic photoreceptor according to the present invention does not have the above-mentioned structure, and as is clear from the Examples and Comparative Examples described below,
Even when subjected to electrophotographic processes continuously, there is little electrical fatigue of the photosensitive layer, so there is no cumulative increase in residual potential that cannot be removed in the photosensitive layer 4, and therefore a long service life can be obtained. In addition, there is no restriction on continuous copying, and it is possible to always stably form a copied image without capri in the background area.

In addition, the electrophotographic photoreceptor according to the present invention is resistant to deterioration factors such as photochemical reactions caused by active light irradiated from exposure lamps and erasing lamps, oxidation effects caused by active species generated by corona discharge, and increases in internal temperature. The carrier transport layer 3 is highly stable and exhibits little change over time in characteristics such as acceptance potential, sensitivity, and residual potential in bright light, and therefore has little natural deterioration due to use, and is extremely easy to maintain and handle.
In this case, it is possible to contain a binder resin at a relatively high concentration without impairing its good properties, and by doing so, the mechanical strength of the photosensitive layer 4 can be increased, and the development resistance and Resistance to mechanical damage such as cleaning resistance increases, and from this point of view as well, the service life is extended.0 As described above, by configuring the carrier transport layer 3 as described above, the electrophotographic photoreceptor It has the characteristic of being able to maintain stable performance especially during continuous use.

According to the electrophotographic photoreceptor according to the present invention, the hydrazone compound in the carrier transport layer used in combination with the carrier-generating substance forms a charge-transfer complex with the electron-accepting substance, which is sensitive to ultraviolet light and transfers carriers. The above-mentioned excellent properties are used to improve the carrier transport efficiency by neutralizing the holes trapped in the layer containing the carrier transport material by the carriers generated by ultraviolet light. It is assumed that this will be obtained. If only the hydrazone derivative represented by the above general formula was used, the carrier transport function would be excellent, but it would deteriorate due to active species with oxidizing effects generated by ultraviolet light, temperature, and corona discharge, and <
There is a drawback that the transportation function deteriorates during the process of reversing.

The present invention has been described above according to the specific structural example shown in FIG. 1 or FIG. The mechanical structure of the electrophotographic photoreceptor can be arbitrarily selected.

For example, as shown in FIG. 3, a suitable intermediate layer 5 may be provided on the conductive support 1, the carrier generation layer 2 may be formed through this, and the carrier transport layer 3 may be formed thereon. . This intermediate layer 5 has a function of preventing free carriers from being injected from the conductive support 1 into the photosensitive layer 4 when the photosensitive layer 4 is charged, and also has the function of preventing the photosensitive layer 4 from being injected into the photosensitive layer 4 integrally with the conductive support. It can have a function as an adhesive layer for adhering to. Materials for the intermediate layer 5 include metal oxides such as aluminum oxide and indium oxide, acrylic resins, methacrylic resins, vinyl chloride resins, vinyl acetate resins, epoxy resins, polyurethane resins, phenol resins, polyester resins, alkyd resins, and polycarbonates. Polymeric substances such as resin, silicone resin, melamine resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride copolymer resin can be used. Alternatively, a carrier transport layer 3 may be formed on the conductive support 1 with or without the intermediate layer 5, and a carrier generation layer 2 may be formed thereon to constitute the photosensitive layer 4. .

In addition, FIG. 5 shows that the photosensitive layer 4 is
``The biological material was solidified with the above-mentioned hydrazone compound (i.e.,
An example is shown in which the layer is formed of a mixed layer of a carrier-generating material phase and a carrier-transporting material phase.

Hereinafter, the present invention will be described in more detail with reference to specific examples.

Example 1 A vinyl chloride-vinyl acetate-maleic anhydride copolymer [Eslec MF-10J (manufactured by Uzukusui Kagaku Kogyo ■)] was deposited on a conductive support made of polyethylene terephthalate with a thickness of 100 μm on which aluminum was vapor-deposited. The thickness is approximately 0.
A 1 μm intermediate layer was provided.

Next, bisazo compound 1 represented by the following structural formula (II)
．． 5. ! i2 was dispersed in 100 m4 of 1,2-dichloroethane using a ball mill for 8 hours, and the resulting dispersion was applied onto the intermediate layer and sufficiently dried to form a carrier generation layer with a thickness of about 0.3 μm. .

On the other hand, a hydrazone compound represented by the following structural formula (i-22) 11.25. ! i' and picryl chloride 0.0
28g and polycarbonate resin [Panlite L-125
0J (Teijin Kasei Co., Ltd. fi>15g) was dissolved in 100mt of 1,2-dichloroethane, the resulting solution was applied onto the carrier generation layer using a doctor blade, and the temperature was 80°C.
It was dried for 1 hour at .degree. C. to form a charge transport layer with a thickness of 15 .mu.m, thereby producing an electrophotographic photoreceptor of the present invention.

This will be referred to as "Sample 1".

Structural formula (■-22): Using the compound 11.25.9 represented by the structural formula (I-1) as the hydrazone compound, tetraptetraphthalic anhydride 0.11.9 as the electron-accepting substance. ! A charge generation layer with a thickness of about 0.3 μm and a charge transport layer with a thickness of 15 μm were formed in the same manner as in Example 1 except that i' was used, thereby producing an electrophotographic photoreceptor of the present invention. did.

This will be referred to as "Sample 2."

Structural formula (I-1): Example 3 Polycarbonate resin 0.7511 and tetrabromophthalic anhydride 0.2. ! i' in 100 ml of 1,2-dichloroethane and the above structural formula (I
The bisazo compound 1.511 shown in I) was added and subjected to ultrasonic dispersion, and the resulting dispersion was coated on a conductive support having an intermediate layer similar to that in Example 1, and a 0.5 μm thick layer was formed. A carrier generation layer was formed.

On the other hand, 11.25 g of the hydrazone compound represented by the above structural formula (I-22) and 15 g of polycarbonate resin "Panlite L-12504 (manufactured by Yondai Kasei Co., Ltd.) were mixed with 1,2-
Dissolved in 100 d of dichloroethane, applied the resulting solution onto the carrier generation layer using a doctor blade, and dried at a temperature of 80° C. for 1 hour to form a charge transport layer with a thickness of 15 μm, Thus, an electrophotographic photoreceptor of the present invention was produced.

This will be referred to as "Sample 3."

Example 4 Polycarbonate resin 0.75f! and tetrabromophthalic anhydride 0.29 and 1,2-dichloroethane 100
1.51 of 4,10-dibromanthanthrone was added to the solution obtained by dissolving it in m1, and ultrasonic dispersion was performed.
The obtained dispersion liquid was applied onto a conductive support having an intermediate layer similar to that in Example 1 to form a carrier generation layer having a thickness of 0.5 μm.

On the other hand, hydrazone compound 1 represented by structural formula (I-1)
1.25g and 0.056g of 3,5-dinitrobenzoic acid
and polycarbonate resin “Panlite L-1250J”
(manufactured by Ryotai Kasei Co., Ltd.) in 100 d of 1,2-dichloroethane, and the resulting solution was applied onto the carrier generation layer using a doctor blade at a temperature of 80°C.
The layer was dried for 1 hour to form a carrier transport layer having a thickness of 15 μm, thereby producing an electrophotographic photoreceptor of the present invention. This will be referred to as "Sample 4."

Comparative Examples 1 to 4 Comparative electrophotographic photoreceptors were produced in the same manner as in Examples 1 to 4, except that no electron-accepting substance was used in Examples 1 to 4. These will be referred to as "Comparative Sample 1" to "Comparative Sample 4", respectively.

Samples 1 to 4 and comparative samples 1 to 4 according to the above Examples and Comparative Examples were transferred to a dry electrophotographic copying machine U-BiX2000 R (
The black paper potential v b (y) and the white paper potential V w (V) at an exposure aperture value of 2.5 are measured using an electrostatic voltmeter model 144D-ID. (Monroe Electronics)
(manufactured by Inc.) and was measured before development. The results are shown in the table below.

Note that the black paper potential here refers to the surface potential of the photoreceptor when the above copying cycle is performed using black paper with a reflection intensity of 1.3 as the original, and the white paper potential refers to the surface potential of the photoreceptor when the original is a black paper with a reflection intensity of 1.3. Represents the surface potential of the body.

(However, in the table, 1. aVb (V) and ΔVw (V) indicate the amount of variation in the black paper potential v b (v) and white paper potential Vw (V), respectively, + indicates increase and - indicates decrease.) The results shown in this table show that for all samples 1 to 4 based on the present invention, the amount of variation in both potentials after 20,000 copies with respect to the initial black paper potential and white paper potential is small and stable. Samples 1 to 4 had a large amount of variation in both potentials, and in particular, the variation in the blank paper potential caused ground spots to appear on the copied image.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIGS. 1, 2, 3, 4, and 5 are cross-sectional views of a portion of each side of the photoreceptor. In addition, in the symbols used in the drawings, 2----
1.-Carrier generation layer 3.-----1.Carrier transport layer 4.----1 Photosensitive layer. Agent: Patent attorney Hiroshi Aisaka (1 other person) No. 11] Chrysanthemum 21st, 31st month

Claims (1)

[Scope of Claims] 1. In a photoreceptor having a carrier generation phase and a carrier transport layer, a hydrazone compound represented by the following general formula is contained in the carrier transport layer, and an electron-accepting substance is contained in the carrier transport layer. and the carrier generation phase. General formula: (However, R1 is a substituted or unsubstituted naphthyl group; R2 is a substituted or unsubstituted alkyl group, aralkyl group, or aryl group; R3 is a hydrogen atom, an alkyl group, or an alkoxy group; R4 and US is a substituted or unsubstituted alkyl group,
Indicates mutually the same or different groups consisting of an aralkyl group or an aryl group. 2. The photoreceptor according to claim 1, wherein a photoreceptor layer comprising a laminate of a carrier generation layer and a carrier transport layer is provided on a conductive support.