JPS60195547A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To provide an electrophotographic sensitive body which has substantial sensitivity and eliminates potential fluctuation between the bright part and dark part during repeated electrification and exposure and to obtain a novel electric charge transfer material in a laminated type photosensitive layer separated in function to a charge generating layer and charge transfer layer by using an electrophotographic sensitive body having a layer contg. a specific hydrazone compd. CONSTITUTION:The hydrazone compd. expressed by the formula is used for the charge transfer material of an electrophotographic sensitive body having the photosensitive layer separated in function to a charge generating layer and charge transfer layer. The charge transfer layer is formed by coating the soln. prepd. by dissolving the hydrazone compd. expressed by the formula and a binder into a suitable solvent and drying the coating. For example, polyacrylate resin, polyvinyl pyrene, etc. are used for said binder. The ratio of said compd. and binder to be compound is 10-500pts.wt. the hydrazone compd. for each 100pts.wt. the binder. The charge transfer layer is laminated on the charge generating layer and the film thickness thereof is made 5-30mu.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to electrophotographic photoreceptors, and more particularly to electrophotographic photoreceptors having a low molecular organic photoconductor that provides improved electrophotographic properties.

Conventionally, inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide are known as photoconductive materials used in electrophotographic photoreceptors. These photoconductive materials have many advantages, such as being able to be charged to an appropriate potential in the dark, having little charge dissipation in the dark, and being able to quickly dissipate the charge when irradiated with light. On the other hand, it has various drawbacks. For example, selenium-based photoreceptors easily crystallize due to factors such as temperature, humidity, dust, and pressure.
In particular, when the ambient temperature exceeds 40° C., there are disadvantages such as significant crystallization and white spots appearing on the image while the chargeability decreases. Cadmium sulfide photoreceptors do not provide stable sensitivity in humid environments, and zinc oxide photoreceptors require the sensitizing effect of sensitizing dyes such as rose bengal. They have the disadvantage that they cannot provide stable images over a long period of time because the sensitive dyes undergo charging deterioration due to corona charging and photobleaching due to exposure light.

On the other hand, various organic photoconductive polymers including polyvinylcarbazole have been proposed, but these I-rimers are superior in terms of film formability and light weight compared to the above-mentioned inorganic photoconductive materials. However, it has been difficult to put it into practical use to date because sufficient film formation properties have not yet been achieved, and inorganic photoconductive materials have problems in terms of sensitivity, durability, and stability against environmental changes. This was because the material was inferior.

In addition, hydrazone compounds disclosed in U.S. Pat. No. 4,150,987, triarylpyrazoline compounds described in U.S. Pat.
Low-molecular organic photoconductors such as 9-styrylanthracene compounds described in JP-A-94828 and JP-A-51-94829 have been proposed. By appropriately selecting the binder used, such low-molecular-weight organic photoconductors can overcome the drawbacks of film-forming properties that had been a problem in the field of organic photoconductive polymers. It cannot be said that the sensitivity is sufficient.

For these reasons, a laminated structure in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer has been proposed in recent years. Electrophotographic photoreceptors using this laminated structure as a photosensitive layer have been developed to improve sensitivity to visible light, charge retention, surface strength, and other aspects. Such electrophotographic photoreceptors are disclosed, for example, in US Pat. No. 3,837,851 and US Pat. No. 3,871,882.

However, electrophotographic photoreceptors using conventional low-molecular-weight organic photoconductors in the charge transport layer have not yet achieved sufficient sensitivity, and when repeatedly charged and exposed, bright areas There are some points that need to be greatly improved, such as fluctuations in potential and dark potential.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photoreceptor that eliminates the above-mentioned drawbacks or disadvantages.

Another object of the invention is to provide a new organic photoconductor.

Another object of the present invention is to provide a novel charge transport material in a laminated photosensitive layer in which a charge generation layer and a charge transport layer are functionally separated.

This object of the present invention is achieved by an electrophotographic photoreceptor having a layer containing a hydrazone compound represented by the following general formula.

In the formula, R and R2 represent an alkyl group such as methyl, ethyl, globil, or ethyl, an aralkyl group such as benzyl, phenethyl, or naphthylmethyl, or a phenyl group, and these may be substituted with halogen, alkoxy, or the like. R,
, R2 represents a residue that, together with the N atom, forms a 5- to 6-membered ring group such as a pyrrolidino group, a piperidino group, or a morpholino group. R5 represents an alkyl group such as methyl, ethyl, globyl, butyl, or an aryl group such as 7-enyl or naphthyl, and these may be substituted with I, alkyl, alkoxy, or the like. Ar represents an aryl group such as phenyl or naphthyl, which may be substituted with halodane, alkyl, alkoxy, or the like.

Ar2 represents an α-naphthyl group or a β-naphthyl group.

Representative examples of the compound represented by general formula (1) are listed below.

Compound example -2 -4 -5 H-9 -10 -11 -13 Next, a synthesis example of the above compound will be shown.

H-1 Synthesis Example α-Chloromethylnaphthalene 50 gr Doaniline 5
When 0 gr is mixed and stirred at room temperature for a short time, white crystals are precipitated with heat generation. The reaction solution was heated at 100'ct to complete the reaction, cooled and extracted with benzene. The extract was dried and distilled under a reduced pressure of 30 μHg at 205-210°C.
Fraction 37.2.9 is obtained. Further, when reconsolidated with methanol, white crystals of N-naphthylmethylaniline 31.3.
Get 9. Melting point: 65.6 to 67.2°C The above N-naphthylmethylaniline 10JF was dissolved in a mixed solvent of ethanol, 50TRt, glacial acetic acid, 50%, stirred at room temperature, and 3.259% of sodium nitrite was added over 10 minutes.
Subsequently, 12.419 g of zinc powder was added over 10 minutes while controlling the temperature not to exceed 35° C. to prepare a hydrazine solution. On the other hand, P-dimethyla is nopenzaldehyde 5. II was dissolved in 40 TIt of ethanol,
Add dropwise to the hydrazine solution from which the zinc dust residue has been removed at room temperature while stirring.

Eventually, the desired hydrazone H-1 is precipitated. Reconsolidated from a mixed solvent of methanol 30-1 MEK 30-, melting point 1
3.29 pale yellow crystals of 49-150° C. are obtained.

Elemental analysis Molecular formula C26H25N.

Calculated value Analytical value CB2.29 82.33 H6,646,6O N 11.07 11.07 For hydrazone compounds of H-2 and below, chloromethylnaphthalene and amine glass 7-tylmethylamine were synthesized according to the above synthesis method. It is synthesized by carrying out a dehydration condensation reaction with various aldehydes after nine nitrosation and reduction reactions.

In a preferred embodiment of the present invention, a hydrazone compound represented by the above general formula can be used as a charge transport material in an electrophotographic photoreceptor in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer.

The charge transport layer according to the present invention is preferably formed by applying a solution of a hydrazone compound represented by the above general formula and a binder dissolved in a suitable solvent and drying the solution. Examples of the binder used here include polyarylate resin, polysulfone resin, polyamide resin,
Acrylic resin, acrylonitrile resin, methacrylic resin, vinyl chloride resin, vinyl acetate m# phenolic resin,
Epoxy resins, polyester resins, alkyd resins, I-licarnates, I-urethanes, or copolymer resins containing two or more repeating units of these resins, such as styrene =! Tazoene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, etc. can be mentioned. In addition to such insulating polymers, organic photoconductive polymers such as polyvinylcarbazole, polyvinylanthracene, and I-rivinylpyrene can also be used.

The blending ratio of the binder and the hydrazone compound is preferably 10 to 500 parts by weight of the hydrazone compound per 100 parts by weight of the binder.

The charge transport layer is electrically connected to the underlying charge generation layer and has the function of receiving charge carriers injected from the charge generation layer in the presence of an electric field and transporting these charge carriers to the surface. are doing. At this time, this charge transport layer may be laminated on or under the charge generation layer. However, it is desirable that the charge transport layer is laminated on the charge generation layer.

Since this charge transport layer has a limit in its ability to transport charge carriers, it cannot be made thicker than necessary. Typically it is 5 microns to 30 microns, with a preferred range of 8 microns to 20 microns.

The organic solvent used when forming such a charge transport layer is
It is preferable to select a binder that varies depending on the type of binder used, or one that does not dissolve the charge generation layer or underlying subbing layer. Specific organic solvents include alcohols such as methanol, ethanol, and isoglonoplainol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide. sulfoxides such as, ethers such as tetrahydrofuran, dioxane, ethylene glycol monomethyl ether, esters such as methyl acetate, ethyl acetate,
Aliphatic I/rhodanized hydrocarbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, and trichlorethylene, or aromatics such as benzene, toluene, xylene, ligroin, monochlorobenzene, and dichlorobenzene may be used. I can do it.

Coating methods include dip coating method, soufflé coating method, spinner coating method, bead coating method,
This can be carried out using a coating method such as a Mayer coating method, a blade coating method, a roller coating method, or a curtain coating method. For drying, it is preferable to dry to the touch at room temperature and then heat dry. Heat drying at a temperature of 30°C to 200°C for 5 minutes to 2
It can be carried out stationary or under blown air for a period of time within a range of hours.

The charge transport layer of the present invention can contain various additives. Such additives include diphenyl, diphenyl chloride, 〇-terphenyl, P-terphenyl, sibutyl phthalate, dimethyl glycol phthalate, dioctyl heptatalate, triphenyl phosphoric acid, methylnaphthalene, benzophenone, chlorinated terphenyl, dimethyl glycol phthalate, lauryl thioglopionate, 3,5-dinitrosalicylic acid,
Examples include various fluorocarbons.

The charge generating layer used in the present invention includes selenium, selenium-tellurium, biryllium, thiopyrylium dyes, phthalocyanine pigments, anthanthrone pigments, dibenzpyrenequinone pigments, pyranthrone pigments, trisazo pigments, disazo pigments, azo pigments, indigo pigments, Quinacridone pigment, asymmetrical quinocyanine, quinocyanine or JP-A-1987-
A separate vapor deposited layer or resin dispersion layer selected from a charge generating material such as amorphous silicon described in Japanese Patent No. 143,645 can be used.

Examples of the charge generating substance used in the electrophotographic photoreceptor of the present invention include the following inorganic compounds and organic compounds.

Charge-generating substances (1) Amorphous silicon (2) Selenium-tellurium (3) Selenium-arsenic (4) Cadmium sulfide 9 ■ In words) 8 ρ S 0 C39) (40) !! ! g ; 4J gusi φ6) (57) φ8) Squaric acid methine dye (59) Incy? dye (C, 1, A2B2O7) (
60) Thioinsico dye (C, Li28800) (6
1) β-type steel phthalocyanine; 1) q (J-w) The charge generation layer can be formed by dispersing the charge generation substance described above in a suitable binder and coating it on the substrate; It can be obtained by forming a vapor-deposited film in a vacuum evaporation apparatus.The binder that can be used when forming the charge-generating layer by coating can be selected from a wide range of insulating resins, including poly-N-vinylcarbazole. , /rivinyl anthracene and polyvinylpyrene. Preferably, polyvinyl 1
Tyral, polyarylate (condensation polymer of bisphenol A and heptalic acid, etc.), polycargenate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide resin, polyamide, polyvinylpyridine, cellulose resin, urethane resin, epoxy resin,
Examples include insulating resins such as casein, polyvinyl alcohol, and polyvinylpyrrolidone. The resin contained in the charge generation layer is 80% by weight or less, preferably 40% by weight or less.
Weight % or less is suitable. Examples of organic solvents used during coating include alcohols such as methanol, ethanol, and isoglopanol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, amides such as N,N-trimethylformamide, N,N-dimethylacetamide, Sulfoxides such as trimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, and ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, chloroform, methylene chloride,
Aliphatic rhodanized hydrocarbons such as dichloroethylene, carbon tetrachloride, trichlorethylene, or benzene,
Aromatics such as toluene, xylene, ligne, monochlorobenzene, dichlorobenzene, etc. can be used.

Coating methods include dip coating method, soufflé coating method, spinner coating method, bead coating method,
This can be carried out using a coating method such as a Mayer coating method, a grade coating method, a roller coating method, or a curtain coating method.

The charge generation layer contains as much of the organic photoconductor as possible in order to obtain sufficient absorbance and is preferably a thin film layer, for example less than 5 microns, in order to shorten the range of the generated charge carriers. is preferably a thin film layer having a thickness of 0.01 micron to 1 micron. This means that most of the incident light is absorbed by the charge generation layer, generating a large amount of charge carriers, and that the generated charge carriers are not deactivated by recombination or trapping. This is due to the need for injection into the charge transport layer.

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. Examples of substrates having a conductive layer include those in which the substrate itself is conductive;
For example, aluminum, aluminum alloy, copper, zinc, stainless steel, aluminum, molybdenum, chromium, titanium, nickel, indium, gold and platinum can be used, and in addition, aluminum, aluminum alloy, indium oxide, tin oxide, tin oxide, etc. can be used. Zolastic resin having a layer formed by vacuum evaporation of indium-tin oxide alloy, etc. (e.g., polyethylene, polyzolopyrene, vinyl chloride, polyethylene terephthalate, acrylic resin, poly, ethylene oxide, etc.), conductive particles (for example,
A substrate obtained by coating glass plastic with a suitable binder (Cargen plastic, glue, silver particles, etc.), a substrate obtained by impregnating plastic or paper with conductive particles, a plastic having conductive I remer, etc. can be used.

A subbing layer having barrier and adhesive functions can also be provided between the conductive layer and the photosensitive layer. Subbing layer, casein,
Polyvinyl alcohol, nitrocellulose, ethylene-
Acrylic acid colimer, polyamide (nylon 6, nylon 66, nylon 610, copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, gelatin,
It can be formed from aluminum oxide, etc.

The thickness of the undercoat layer is suitably 0.1 to 5 microns, preferably 0.5 to 3 microns.

When using a photoreceptor in which a conductive layer, a charge generation layer, and a charge transport layer are laminated in this order, the hydrazone compound has hole transport properties, so it is necessary to negatively charge the surface of the charge transport layer. In the exposed area, holes generated in the charge generation layer are injected into the charge transport layer, and then reach the surface to neutralize the negative charges, resulting in attenuation of the surface potential and an electrostatic contrast between the layer and the unexposed area. During development, it is necessary to use a positively charged toner, contrary to the case where an electron transport material is used.

In another specific example of the present invention, the above-mentioned disazo pigment or pyrylium dyes, thiapyrylium dyes, selenapyrylium dyes, and benzopyrylium dyes disclosed in U.S. Pat. No. 3,554,745, U.S. Pat. , benzothiapyryllium dye, naphthopyryllium dye, naphthothiapyrylium dye, and other photoconductive pigments and dyes can also be used as sensitizers for human 2-sin.

Further, in a specific example of the present invention, a eutectic complex of a pyrylium dye and an electrically insulating polymer having an alkylidene diarylene moiety, which is disclosed in US Pat. No. 3,684,502, can also be used as a hydrazone sensitizer. This eutectic complex is composed of, for example, 4-[4-bis-(210loethyl)7minophenyl]-2,6-cyphenylthiapyrylium-chlorate and poly(4,4'-isoglopylidene diphenylene cartilage). ester) to a halogenated hydrocarbon solvent (
For example, dichloromethane, chloroform, carbon tetrachloride,
1.1-1#Olethane, 1.2-dichloroethane, 1
．． 1.2-) IJ dichloroethane chlorobenzene,
The particulate eutectic complex is prepared by adding a nonpolar solvent (e.g., hexane, octane, decane, 2,2,4-dichlorobenzene, 2,2,4-dichlorobenzene, ligroin) to it after KI decomposition (furomobenzene, 1,2-dichlorobenzene). obtained as. The electrophotographic photoreceptor in this specific example is styrene! Tadienco I remer, silicone resin, vinyl resin, vinylidene chloride-acrylonitrile copolymer, styrene-acrylonitrile copolymer, vinyl acetate-hinichloride A/:l/li-v-, polyvinyl butyral, I-lymethyl methacrylate, poly-N-butyl methacrylate) 1. If Solyesters Binders such as cellulose esters can be included along with the hydrazone and the eutectic complex.

The electrophotographic photoreceptor of the present invention can be used not only for electrophotographic copying machines, but also for radar printers, CRT printers,
It can also be widely used in electrophotographic application fields such as electrophotographic plate making systems.

According to the present invention, it is possible to provide a highly sensitive electrophotographic photoreceptor, and the variation in bright area potential and dark area potential is small when repeatedly charged and exposed, and photomemory properties are effectively improved. It has the advantage of being able to

Hereinafter, the present invention will be explained according to examples.

Example 1 Pigment 7y was purified by sequentially refluxing β-type steel phthalocyanine (trade name: Lionol Blus NCB Taner) manufactured by Toyo Ink Mfg. Co., Ltd. in water, ethanol and benzene, and then filtering it; :4?Reester Adhesive 49,000 (solid content 20%)
J14F; Toluene 35I; Dioxane 35I mixed, ? - Disperse the coating solution by dispersing it in Lumil for 6 hours.
1III. This coating solution was coated onto an aluminum sheet using a Meyer perforator to give a dry film thickness of 0.5 microns to form a charge generation layer.

Next, the above exemplified compound H-1 was added as a charge transport compound to 7
A solution obtained by stirring and dissolving 7 g of g and I recarbonate resin (trade name: 9 N Light 11300 J, manufactured by Teijin Kasei Ltd.) in a mixed solvent of 35 g of tetrahydrofuran and 351 chlorobenzene was used as the charge generating layer. On top, apply it with i-earper to a dry film thickness of 11 microns.
An electrophotographic photoreceptor having a photosensitive layer having a two-layer structure was prepared.

The electrophotographic photoreceptor produced in this way was manufactured by Kawaguchi Electric Co., Ltd.
The sample was corona-charged at -5 kV using a static copying paper tester Model-8P-428, held in a dark place for 1 second, and then exposed to light at an illuminance of 5 lux to examine the charging characteristics.

The charging characteristics include the surface potential (Vo) and the amount of exposure required to attenuate the potential (V+) to A when dark decayed for 1 second (
E'A) was measured.

Furthermore, in order to measure the fluctuations in bright area potential and dark area potential when repeatedly used, the photoreceptor prepared in this example was
, 6kV corona charger, exposure amount 10 Lux, m・C
The sticker was affixed to the cylinder of an electrophotographic copying machine equipped with an exposure optical system, a transfer device, a transfer charger, a static elimination exposure optical system, and a cleaner. This copying machine uses cylinder drive to
The structure is such that an image can be obtained on transfer paper. Using this copying machine, the initial bright area potential (vL) and dark area potential (VD
) and his light potential (vL) and dark potential (vtl) were measured after 5000 uses. The results are shown below.

V,: -560 melt"+: 545 Zalto E%: 6.21ux, t@c Initial VD: -600 volt VL Knee 45 gelt after 5000 cycles vo knee 590/rut vL: 6Qg Rut Example 2~ 17 In each of these Examples, Exemplified Compound H-1 was replaced with Exemplified Compound H-1 as the charge transport compound used in Example 1.
-2, H-3, H-4, H-5.

H-6, I (-7, H-8, H-9, H-10゜H-1
1, H-12, H-13, H-14゜f(-15, H-
An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that No. 16, H-17 was used.

The electrophotographic properties of each photoreceptor were measured in the same manner as in Example 1. The results are shown below.

■ ■ ■ [Example 17 4-(4-dimethylaminophenyl')-2,6-diphenylthiapyrylium no-9-chlorate 31 and the exemplified hydrazone compound (H-7) were combined with 5I to I-lyester (
Polyester Adhesive 49000: De-tool? Toluene (50)-dioxane (50) solution 100
and dispersed in a ball mill for 6 hours. This dispersion was applied onto an aluminum sheet using a Mayer Parr so that the film thickness after drying was 15 microns.

Example 1 The electrophotographic characteristics of the photoreceptor produced in this way
It was measured in the same manner as. The results are shown below.

Vo: -559 & Ruto V, : -535 Galt E%: 4.71ux, s@c Initial VD: -59 (l Ruto VL Knee 45♂ After 5000 rotations VD: -575 Volts VL: -55 Melt implementation Example 18 Ammonia aqueous solution of casein (casein 1
1.2 fI, 28 thiammonia water B, water 2221 nt)
was coated with Mayer Par and dried to form an adhesive layer with a thickness of 1 micron.

Next, 5 g of a disazo pigment having the following structure and 21 zotyral resin (degree of butyralization 63 mol) were mixed with 9 mol of ethanol.
After dispersion with a solution dissolved in No. 5-5, the charge generating layer was coated on the adhesive layer after death to form a charge generating layer having a thickness of 0.4 icm after drying.

Next, 5 g of the above-mentioned hydrazone compound (H-13)
A solution prepared by dissolving 5 g of poly-4,4'-dione diphenyl-2,2-globan carbonate (viscosity average molecular weight 30,000) in 150 d of dichloromethane was coated on the charge generating layer and dried, resulting in a film thickness of 11 microns. An electrophotographic photoreceptor was prepared by forming a charge transport layer.

The electrophotographic properties of the uniformly prepared electrophotographic photoreceptor were measured in the same manner as in Example 1. The results are shown below.

V, : -550 delt v1 : -540 volt E')4 : 5.61ux, sec Initial VD : -565 gelt ML m 55 gelt VD after 5000 cycles endurance: -555rJ? Gelt VL: -65 Gelt Example 19 A 0.2 m thick molybdenum plate (substrate) whose surface was cleaned was fixed at a predetermined position in a glue discharge deposition tank. Next, the tank was completely evacuated to a pressure of about 5 x 10-'torr. Thereafter, the input voltage of the heater was increased to stabilize the molybdenum substrate temperature at 150°C.

After that, hydrogen gas and silane gas (15 volumes S for hydrogen gas) were introduced into the tank, and the gas flow rate and the main pulp of the evaporation tank were adjusted to stabilize it at 0.5 torr.Next, 5 MHz high frequency power was applied to the induction coil. was applied to generate a glow discharge inside the coil in the tank, resulting in an input power of 30 W. Under the above conditions, an amorphous silicon film was grown on the substrate, and the same conditions were maintained until the film thickness reached 2 μ, then the glow discharge was stopped. After that, the heating heater and high frequency power supply were turned off, and after waiting for the substrate temperature to reach 100°C, the hydrogen gas and silane gas outflow pulp was closed, and the inside of the tank was heated to 1O-5 Torr.
After reducing the pressure to below r, the pressure was returned to atmospheric pressure and the substrate was deposited. Next, a charge transport layer was formed on this amorphous silicon layer in exactly the same manner as in Example 1 except that Exemplified Compound H-14 was used as the charge transport compound.

The photoreceptor obtained in this way was installed in a charging exposure experimental device.9
It was corona charged at 6 kV and immediately irradiated with a light image. The light image was illuminated through a transmission test chart using a tungsten lung light source. Immediately thereafter, use a charged developer (
A good toner image was obtained on the photoreceptor surface by cascading the toner (containing toner and carrier) onto the photoreceptor surface.

Example 20 4-(4-dimethylaminophenyl)-2,6-zophenylthiapyrylium parent-chlorate 3I and I(4
, 4'-isoglopylidene diphenylene cargenate)
After sufficiently dissolving 3F in 200° of dichloromethane, 100° of toluene was added to precipitate the eutectic complex. After separating this precipitate with F, dichloromethane was added to dissolve it again.
Next, n-hexane 100- was added to this solution to obtain a precipitate of a eutectic complex.

This eutectic complex 5flt-yf! Rivinyl Ptyral 2I
The mixture was added to 95 ml of methanol solution containing the following, and dispersed in a mail mill for 6 hours. This dispersion was applied onto an algae plate having a casein layer using a Mayer parser so that the film thickness after drying was 0.4 microns to form a charge generation layer.

Next, a cover layer of a charge transport layer was formed on this charge generation layer in the same manner as in Example 1 except that Exemplary Compound H-16 was used.

The electrophotographic properties of the photoreceptor thus prepared were measured in the same manner as in Example 1. The results are shown below.

V, : -5 sos V, : -575 Melt El : 4.81ux, see Initial vD : -600 is Rut V, : -40 gelt VD after 5000 times endurance: -590 Delt VL : -55+N Rut Example 21 5 g of the same eutectic complex used in Example 20 and 5.9 g of the above-mentioned hydrazone compound (H-7) were mixed into a polyester (Polyester Adhesip 49000: manufactured by De:Lbon) tetrahydro 7 run liquid 150- In addition, the mixture was thoroughly mixed and stirred. This liquid was applied onto an aluminum sheet using a Mayer Parr so that the film thickness after drying would be 15 μm.

The electrophotographic properties of this photoreceptor were measured in the same manner as in Example 1. The results are shown below.

vo: -630 gelt V: -615 is root EVx: 4.21ux, sec Early period VD: -635 Melt vL: -45 melt After 5000 times durability vD: -600 Gelt VL Knee 55 Ruto

Claims (1)

[Claims] An electrophotographic photoreceptor specially designed to contain a hydrazone compound represented by the following general formula, where R,,R2
is a residue that forms a 5- to 6-membered ring together with an alkyl group, an aralkyl group, a phenyl group, or an NR atom that may have a substituent,
R, l-1 is an alkyl group or aryl group which may have a substituent, Ar1 is an aryl group which may have a substituent, A
r2 is a naphthyl group.