JPS61177461A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain a photosensitive body high in sensitivity, small in residual potential, and high in electrostatic charge transfer efficiency, accordingly, raisable in copying speed by incorporating a specified hydrazone compd. in a photoconductive layer. CONSTITUTION:The electrophotographic sensitive body has the photosensitive layer contg. at least one of compds. as a charge transfer material, preferably, in an amt. of 10-300pts.wt. per 100pts.wt. of a binder resin, represented by formula [I] in which R1, R2 are each alkyl, aryl, or heterocyclic; each of R3-R>=6 is H, halogen, alkyl, or alkoxy, and at least one of R3-R6 is a group of -SR9, R9 being alkyl, aralkyl, or aryl; and R7, R8 are each alkyl, alkoxy, aryl, or heterocyclic.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to an electrophotographic photoreceptor, and more specifically, the present invention relates to an electrophotographic photoreceptor, and more specifically, a photoconductive layer formed on a conductive support has a ,
By containing a novel hydrazone compound, an electrophotographic photoreceptor having excellent photosensitivity and durability is provided.

(Prior Art) The electrophotographic method has already been published by Carlson in US Patent No. 2.297.
As disclosed in No. 691, this photographic method is a clever combination of electrostatic phenomena and photoconductive phenomena, in which two surfaces of a photoconductive photoreceptor are uniformly charged by corona discharge etc. in a dark place. After that, the optical image is converted into an electrostatic latent image using photoconductivity,
This is an image forming method in which colored electrically charged powder (toner) is attached to the image to form a visible image.

The basic electrical and photoelectric properties required of a photoreceptor in such electrophotography are that it can be charged to an appropriate potential in a dark place, that this potential can be maintained for an appropriate amount of time, and that it can be charged quickly by light irradiation. For example, the electric charge can be dissipated.

In such photoreceptors, amorphous selenium,
Inorganic photoconductive materials such as cadmium sulfide and zinc oxide have been widely used. Although these inorganic materials satisfy the above conditions, they also have some drawbacks. For example, cadmium sulfide or zinc oxide is used as a photoreceptor by dispersing it in a resin as a binder.

Since it has mechanical defects such as smoothness, flexibility, hardness, tensile strength, and abrasion resistance, it cannot withstand repeated use as it is. Furthermore, when using cadmium sulfide, consideration must also be given to hygiene issues.

In addition, amorphous selenium must be manufactured using vapor deposition, which not only increases manufacturing costs but also makes it difficult to process into a belt shape due to lack of flexibility.
It has drawbacks such as the toxicity of selenium and its sensitivity to heat and mechanical shock, so care must be taken when handling it.

In recent years, in order to eliminate the drawbacks of these inorganic photoreceptors,
Research on organic photoreceptors is progressing, and organic photoreceptors.

Easy to form a film, easy to manufacture, lightweight.

2 because it has many advantages of flexibility and polymorphism in spectral sensitivity.
Various organic photoreceptors have been proposed, and some are in practical use.

For example, poly-N-vinylcarbazole and 2.4°7-
photoreceptor consisting of dolinitrofluoren-9-one (US Pat. No. 3,484,237), poly-N-vinylcarbazole sensitized with pyrylium salt dye (Japanese Patent Publication No. 4B-25658), Photoreceptor whose main component is a eutectic complex consisting of a dye and a resin
Publication No.) etc.

Additionally, an electrophotographic photoreceptor has been proposed that combines a substance that generates electric charge when exposed to light (called a charge-generating substance) and a substance that can transport the generated electric charge (called a charge-transporting substance). . For example, U.S. Patent No. 3.791.
No. 826 describes a photoreceptor in which a charge transport layer is provided on a charge generation layer, and U.S. Pat. No. 3,764,315 describes a photoreceptor in which a charge generation material is dispersed in a charge transport material A photoreceptor with a This kind of charge generation and charge transport.

By sharing the functions with different substances,
In other words, by the combination of a charge generating substance and a charge transporting substance,
Its properties are better and a useful photoreceptor is provided.

Until now, many charge generating substances useful in this type of photoreceptor have been known. On the other hand, various materials have been proposed as charge transport materials.

The current situation is that it is difficult to say that the situation is necessarily satisfactory.

The basic properties of an excellent charge transport material are:

When charged, it must be able to maintain a sufficient potential, it must be able to sufficiently transmit light of an effective wavelength to generate charges from the charge-generating substance, and it must also be able to sufficiently hold the electric charge generated by the charge-generating substance. It has the ability to promptly transport. In addition, as for the practically required properties, it can be used alone or dissolved in a binder.

It is necessary to be able to form a uniform film and to not cause deterioration or change in electrostatic properties under harsh environmental conditions due to temperature, humidity, ozone, NOx, etc. generated during corona discharge. So far, as charge transport materials of this type, polyphenyl compounds such as triphenyl have been classified by chemical structural formula, U.S. Pat. No. 3.717.462, U.S. Pat. 55-52
064, diarylalkane compounds described in U.S. Pat. No. 3,820,989, U.S. Pat. No. 3,189.4.
2,5-bis(P-diethylaminophenyl)-1,3,4-oxadiazole described in No. 77, pyrazoline compounds described in U.S. Patent No. 3'837.851, etc. is a relatively excellent charge transport material that has been proposed in recent years. However, the current situation is that these charge transport materials do not satisfy all of the above conditions.

(Problems to be Solved by the Invention) The present invention provides an electrophotographic photoreceptor having excellent sensitivity, repeatability, durability, and the like.

[Structure of the invention]

(Means for Solving the Problem) As a result of intensive research, the present inventors discovered that a hydrazone compound with a specific structure is a truly useful charge transport material for electrophotographic photoreceptors, and further discovered that The present invention was completed by discovering that an electrophotographic photoreceptor using a charge transporting material has excellent properties.

Specifically, the present invention provides an electrophotographic photoreceptor having excellent properties using a hydrazone derivative having a novel structure.

An object of the present invention is to provide an electrophotographic photoreceptor that contains a novel charge transporting substance, exhibits high sensitivity and low residual potential, and has high charge transport efficiency, so that copying speed is high. Another object of the present invention is to use it as a photoreceptor for repetitive transfer type electrophotography in which charging, exposure, development, and transfer steps are repeated.

To provide an electrophotographic photoreceptor with excellent durability and environmental friendliness, which has little fatigue deterioration due to repeated use, maintains stable characteristics under various harsh environments such as high temperature rather than low temperature, and high humidity than low humidity. It is in.

This object of the present invention is achieved by containing at least one compound represented by the following general formula (1) as a charge transport substance.

General formula (I) R, / where R1 or R2 is each independently an alkyl group, an aryl group, or a heterocyclic residue.

R1 and R2 may form a heterocyclic residue. Rj,
At least one of R,, Rj or R6 has the general formula (
It is a substituent represented by n).

General formula (n) S R9 (In the formula, R9 is an alkyl group that may have a substituent.

Indicates an aralkyl group or an aralkyl group. ) RJ, Rμ
, Rj or R, other than the substituents represented by general formula (II), are each independently a hydrogen atom, a halogen atom, an alkyl group, or an alkoxy group. R and Rj are each independently an alkyl group, an aralkyl group, an aryl group, or a heterocyclic residue, and R-1 and R9 may form a heterocyclic residue. n is O or 1.

To further explain the substituents, the alkyl group includes a methyl group, an ethyl group, a linear or branched propyl group, a butyl group, a pentyl group, and a hexyl group.

Substituents such as heptyl, octyl, and stearyl groups; alkoxy groups include methoxy, ethoxy, propoxy, butoxy, and hexyloxy groups.

Substituents such as benzyloxy group; Aralkyl group refers to substituents such as benzyl group, phenethyl group, cinnamyl group, benzhydryl group, trityl group, naphthylmethyl group;
Aryl groups include phenyl, naphthyl, anthryl, pyrenyl, and acenaphthyl groups.

Substituents such as fluorenyl group; What is a heterocyclic residue?

Substituents such as pyridyl, thiazolyl, and benzoxacylyl groups (provided that R+ and RL+ or R
When 1 and Rg form a heterocyclic residue, substituents such as a piperidino group and a morpholino group are used.

The compound of the present invention represented by the general formula (1) can be produced, for example, by the method shown below.

This is a method in which hydrazine represented by the following general formula (III) or its mineral acid salt is reacted with an aldehyde represented by the general formula (IV) in an aqueous solvent.

General formula (III) (wherein R1 or Rr is the same as general formula (1)) General formula (rV) (wherein, Rl * RZ I RJ I R, R or Rj is general formula (1)) (Similarly) As the solvent, a wide range of non-reactive organic solvents can be used, but preferably alcohols such as methanol and ethanol, dimethylformamide, dioxane, etc. can be used alone or in combination.

In another method, hydrazine represented by the following general formula (V) or its mineral acid salt is reacted with an aldehyde compound represented by the above general formula (Vl) in a solvent.

General formula (V) H,L N-NH-R (in the formula, R9 is the same as in general formula (1)) Then, in a solvent with a compound represented by the following general formula (Vl), preferably under basic conditions. By reacting with 2
The hydrazone compound of the present invention can be obtained.

General formula (Vl) R1-X (wherein, X represents a negative group such as a halogen atom, and R
9 is the same as in general formula (1)) As the solvent, a wide range of non-reactive solvents can be used, but preferably protic solvents such as water and alcohols, or aprotic polar solvents such as dimethyl sulfoxide and dimethyl formamide. Solvents, acetone, ketones such as methyl ethyl ketone, benzene.

Aromatic hydrocarbons such as toluene and xylene, ethers such as tetrahydrofuran and dioxane, dichloromethane,
Chlorinated hydrocarbons such as 1,2-dichloroethane or amines such as pyridine and triethylamine can be used alone or in combination.

Bases include sodium hydroxide and potassium hydroxide.

Potassium carbonate, sodium methylate, sodium hydride, etc. are used.

Two representative examples of the hydrazone compounds used in the present invention obtained by such a synthesis method are listed below.

[Hydrazone compound]

O5 size 1
One example is RotoCl. These compounds can be used alone or in combination of two or more.

The photoreceptor of the present invention contains the above-mentioned hydrazone compounds, and photoreceptors with various characteristics can be obtained depending on how these hydrazone compounds are applied. For example, a hydrazone compound as a charge transport substance is provided on a conductive support substrate in the same layer as a charge generation substance, which is usually referred to as a single-layer photoreceptor, or a first layer mainly containing a charge generation substance. and.

It can be used in a structure commonly called a laminated type photoreceptor, which is formed by configuring two types of second layers mainly containing a charge transporting substance on a conductive supporting substrate.

These configurations are appropriately selected depending on the polarity of the photoreceptor used. Further, examples of charge generating substances used in the present invention include the following.

Inorganic compounds include selenium, selenium alloys, and CdS.

Although inorganic optical semiconductors such as ZnO, C-dse, and amorphous silicon can also be used, it is preferable to use organic charge-generating substances. Examples of organic charge-generating substances include metal phthalocyanine and metal-free phthalocyanine. Phthalocyanine pigments, azo dyes such as monoazo dyes and disazo dyes, indigo pigments,
Dyes and pigments such as quinacridone pigments, indanthrene pigments, xanthine dyes, benzimidazole pigments, perylene pigments, squalic menane dyes, or eutectic complexes formed from biryllium salt dyes and polycarbonate resins, electron-donating properties such as polyvinyl carbazole, etc. Examples include a charge transfer complex consisting of a substance and an electron-accepting substance such as TNF, but it is particularly preferable to use a phthalocyanine pigment.

Since the hydrazone compound in the present invention does not have film-forming ability by itself, a binder resin is used to form it as a photosensitive layer. Further, since charge generating substances cannot form a film by themselves except for polymeric resins such as polyvinylcarbazole, a binder may be used as necessary.

The binder preferably used in the present invention is a highly electrically insulating film-forming polymer or copolymer. Such high molecular polymers and copolymers,
``Binders preferably used in the present invention include phenolic resins, polyester resins, vinyl acetate resins, polycarbonate resins, polypeptide resins, cellulose resins,
Polyurethane resin, polyvinylpyrrolidone, polyethylene oxide, polyvinyl chloride resin, starch, polyvinyl alcohol.

Acrylic copolymer resin, methacrylic copolymer resin.

silicone resin, polyacrylonitrile copolymer resin,
Polyacrylamide, polyvinyl butyral.

Examples include polyvinyl carbazole and polyvinylidene chloride resin. These polymeric binders can be used alone or in a mixture of two or more, but the binders that can be used in the present invention are not limited to these. If necessary, a charge generation layer containing a charge generation substance as a main component may be provided via an intermediate layer if necessary, and a charge transport material containing a charge transport substance as a main component may be provided adjacent to the layer. Also, if such a laminated structure is used.

Which of the charge generation layer and the charge transport layer is to be used as the upper layer is determined depending on whether the chargeability is positive or negative.

Generally, when negatively charged, it is advantageous in terms of characteristics to have a charge transport layer as an upper layer. In addition, two photoreceptors of the present invention.

In the case of a laminated structure consisting of separate layers of a charge generation layer and a charge transport layer, the charge generation layer may be formed directly on the conductive support or, if necessary, with an intermediate layer such as an adhesive layer or a barrier layer provided thereon. ■ Apply vacuum evaporation, ■ Apply a solution of the charge-generating substance dissolved in an appropriate solvent, or ■ Minimize the charge-generating substance in a dispersion solvent using a ball mill, attritor, etc., and add a polymer binder as necessary. It can be provided by a method such as coating a dispersion obtained by mixing and dispersing with. The polymer binder used at this time may be the same as that used for the charge transport layer.

Alternatively, it may be a single photosensitive layer comprising a hydrazone compound according to the present invention and a binder.

In addition, the hydrazone compound according to the present invention has a binding agent of 10
Preferably, the amount of the charge transport material is 10 to 300 parts by weight per 0 parts by weight. However, the present invention is not limited only to this range. The thickness of this photosensitive layer is determined by the required photosensitivity and durability, as well as the mixing ratio of the charge generating substance and the charge transporting substance to the binder. , the thickness of the photosensitive layer on the supporting conductive substrate is 50 microns or less.

Preferably, the thickness is about 7 to 30 microns, which is suitable from the viewpoint of flexibility of the film.

The photosensitive layer can also be coated with a layer that serves as a protective layer, if necessary.

The support used in the electrophotographic photoreceptor of the present invention includes:

Any material may be used as long as it is imparted with electrical conductivity, and any type of electrically conductive layer conventionally used may be used. Specifically, aluminum and copper.

Metals such as stainless steel and brass, aluminum, plastics on which indium oxide, tin oxide, etc. are vapor-deposited or laminated, or conductive particles 1 For example, carbon black,
Examples include plastics in which tin particles and aluminum particles are dispersed. Also, regarding its shape, it can be sheet-like or cylinder-like.

Other items are also acceptable. 2. When using the electrophotographic photoreceptor according to the present invention, the light source is usually a halogen lamp or the like, and when the charge generating substance is phthalocyanine, the sensitivity is 750 nm or more.
Laser light such as a gallium-aluminum-arsenic semiconductor laser (oscillation wavelength: 780 nm) can also be used.

Next, the present invention will be explained in more detail with reference to synthesis examples and examples, but the present invention is not limited to the following examples. In the following examples, "parts" refer to parts by weight.

Synthesis example 1 A synthesis example of compound (1) of the present invention will be shown.

Add 31 parts of phosphorus oxychloride to 3 parts of dimethylformamide at 15-20°C, and then add 21 parts of N,N-diethyl-3-ethylthioaniline at the same temperature to make 50-60%
Stir at ℃ for 3 hours. After cooling the reaction solution, add 200 g of ice water
Next, neutralize with sodium hydroxide and adjust the pH.
After reducing the amount to 9 to 1O, the mixture is cooled, filtered, washed with water, and dried to obtain 21 parts of aldehyde having the structure shown below.

Next, 19 parts of the above aldehyde was added to 96 parts of ethanol.
19 parts of 1-diphenylhydrazine hydrochloride and 2 parts of acetic acid as a catalyst are added and stirred at 70-80°C for 2 hours. After cooling the reaction solution and filtering the precipitated crystals, they are suspended in aqueous ammonia, filtered, washed with water, and dried to obtain 22 parts of compound (1).

18 parts of pure product are obtained by recrystallization from acetonitrile.

Synthesis example 2 A synthesis example of compound (5) of the present invention will be shown.

After adding 25 parts of phosphorus oxychloride to 66 parts of dimethylformamide at 15 to 20°C, 23 parts of N,N-dipropyl-2-methylthio-3-ethylaniline was added at the same temperature, and the mixture was heated at 60 to 70°C for 3 hours. Stir.

After the reaction solution was cooled, it was poured into 1600 parts of ice water.

Next, after neutralizing with sodium hydroxide to adjust the pH to 9 to 10, the mixture is cooled, filtered, washed with water, and dried to obtain 21 parts of aldehyde having the structure shown below.

Next, 20 parts of the above aldehyde, 8 parts of phenylhydrazine, and 1 part of p-toluenesulfonic acid as a catalyst are added to 83 parts of ethanol, and the mixture is stirred at 70 to 80°C for 2 hours. By cooling the reaction solution, filtering and drying the precipitated crystals, 20 parts of hydrazone having the following structure is obtained.

Next, 1 part of sodium hydride was added to 48 parts of dimethylformamide.
．． After adding 8 parts at 15-20°C, the above hydrazone 18
1 part at the same temperature. Then, 8 parts of butyl bromide are added dropwise. After stirring at the same temperature for 3 hours, the compound (5) was poured into 1000 parts of ice water, filtered, washed with water, and dried.
You can get 9 copies. 15 parts of pure product are obtained by recrystallization from ethyl acetate.

Synthesis example 3 A synthesis example of the compound (11) of the present invention will be shown.

After adding 34 parts of phosphorus oxychloride to 80 parts of dimethylformamide at 15 to 20°C, 47 parts of N,N-diphenyl-2,3,5-)(ethylthio)aniline was added at the same temperature to give 50 to 60 parts of dimethylformamide. Stir at ℃ for 3 hours. After the reaction solution was cooled, it was poured into 2000 parts of ice water. Next, neutralize with sodium hydroxide to adjust the pH to 9-10, cool and filter.
By washing with water and drying, 45 parts of aldehyde having the following structure is obtained.

Next, 41 parts of the above aldehyde and 1 part of ethanol were added to 107 parts of ethanol.
-13 parts of methyl-1-phenylhydrazine and 3 parts of acetic acid as a catalyst are added and stirred at 70-80°C for 2 hours.

After cooling the reaction solution and filtering the precipitated crystals, they were suspended in aqueous ammonia, filtered, and washed with water.

By drying, 40 parts of compound (11) are obtained.

32 parts of pure product are obtained by recrystallization from acetonitrile.

Example 1 40 parts of copper phthalocyanine and 0.5 parts of tetranitrocopper phthalocyanine are dissolved in 500 parts of 98% concentrated sulfuric acid with thorough stirring. The molten liquid was poured into 5000 parts of water to precipitate a composition of copper phthalocyanine and tetranitrocopper phthalocyanine, which was then filtered nine times, washed with water, and dried at 120° C. under reduced pressure.

Next, 1 part of this composition, 2.5 parts of compound (1), acrylic polyol (manufactured by Takeda Pharmaceutical Co., Ltd., Takelac A-70
2) A composition consisting of 3.6 parts, 0.5 parts of epoxy resin (manufactured by Shell Chemical Co., Ltd., Epon 1007), 1.2 parts of methyl ethyl ketone, and 1.2 parts of cellosolve acetate was kneaded in a magnetic ball mill for 48 hours. A photoconductive composition is obtained.

Next, this photoconductive composition was roll coated onto the aluminum of a laminate film of a 5 micron thick aluminum foil and a 75 micron polyester film to a dry film thickness of 8 microns, and uniformly heated to 110°C. Every hour during the opening hours.

It was used as an electrophotographic photoreceptor. +5.7 KV for the sample thus obtained, corona gap 10 m+++, 10
A corona discharge is applied at a charging speed of m+/win, and 10 seconds after the discharge is stopped, exposure is performed using a 2854 tungsten light source at an illuminance of 10 Lux. The amount of light irradiation required for the potential immediately before exposure to decrease by 50% at this time was defined as the sensitivity. The sample measured in this way had a maximum surface charge of 57
0 V, dark decay rate 21%, sensitivity 4.3 Lux.

see, the residual potential was 19 V, and both chargeability and sensitivity were values sufficient for practical use. No induction was observed in 1 surface potential decay during charging exposure, and a 5-curve light decay curve was exhibited. In addition, this photoconductor was positively charged with a copying machine for 10
I made 000 copies in a row.

The resulting image has excellent gradation.1 Even when copying an ordinary photograph as an original, a beautiful image can be obtained in terms of detailed intermediate color density, there is no change in sensitivity, and there is no scratch on the photoreceptor. However, a clear image with no such scratches was obtained in the copied image.

Examples 2 to 4 In Example 1, compound (2) was used instead of compound (1).
, (5) or (9), respectively, Example 1
When tested in the same manner as in Example 1, both chargeability and sensitivity were sufficient for practical use.

No induction was observed in one surface potential decay during charging exposure, and the repeatability was also good.

Example 5 40 parts of copper phthalocyanine and 1.5 parts of dinitrometal-free phthalocyanine are dissolved in 100 parts of 98% concentrated sulfuric acid with thorough stirring. Pour the dissolved liquid into 1000 parts of water,
After the phthalocyanine composition is precipitated, it is filtered once, washed with water, and dried at 120° C. under reduced pressure. 1 part of this composition and 3 parts of compound (3) were dispersed in a ball mill along with 4 parts of polycarbonate resin (Kijin Panlite L-1250) and 10 parts of tetrahydrofuran, and the liquid was sprayed into an aluminum cylinder with a thickness of 10 μm. After coating, it was dried to prepare an electrophotographic photoreceptor. The electrophotographic properties of the thus obtained sample were measured in the same manner as in Example 1. The sample measured in this manner had a maximum surface charge amount of 610 parts, a sensitivity of 3.7 Lux, sec, and its light attenuation curve showed 3 curves without induction. too,
After making 10,000 copies, clear images with excellent gradation and no change in sensitivity were obtained both in the initial and final images.

Example 6 2 parts of compound (8) for 1 part of ε-type copper phthalocyanine,
Disperse 0.8 parts of triphenylmethane, 4 parts of acrylic resin, and 20 parts of cellosolve acetate in a ball mill,
Thereafter, the samples were measured in the same manner as in Example 1.

The obtained light attenuation curve is 3 curves without induction, the maximum surface potential at this time is 560 V, and the dark attenuation rate is 18%.
, sensitivity 3.8 Lux, sec + residual potential 19V, and also in live-action tests.

The same results as in Example 1 were obtained.

Example 7 10 parts of copper phthalocyanine obtained in Example 1.

Thermosetting acrylic resin 32 parts, melamine resin 8 parts and butyl acetate (cellosolve acetate) (1:1) 50
A photoconductive coating material was prepared by kneading the composition consisting of the following parts in a ball mill for 24 hours, and this coating material was coated on an aluminum support to a thickness of about 1 .mu.m and cured to form a charge generating layer.

Next, polycarbonate resin (Panlite L-1250
) and 3 parts of polyester resin (manufactured by Gutdeyer) were mixed with tetrahydrofuran and 100 parts of toluene solvent. The weight ratio of solvents is 9:1.

9 parts of compound (1) were added together with 0.02 part of silicone oil. This liquid was applied onto the charge generation layer to a thickness of about 15μ and dried at 80° C. to form a charge transport layer to obtain a laminated photoreceptor.

When this photoreceptor was corona charged at -6.5 KV for 0.2 seconds, the surface potential was -830 V, and the sensitivity was 3.
5 Lux, sec, and was an extremely highly sensitive photoreceptor.

Examples 8 to 11 In Example 7, compound (4) was used instead of compound (1).
, (6), (11) or (12) respectively,
When tested in the same manner as in Example 7, both chargeability and sensitivity were of sufficient value for practical use as in Example 7, and no induction was observed in 1 surface potential attenuation upon charging exposure.
Furthermore, the repeatability was also good.

Example 12 98 parts of tetrahydrofuran was added to 2 parts of Guianpoule (CI21180), and the mixture was crushed and mixed in a ball mill to obtain a charge-generating pigment coating liquid. This was applied using a doctor blade onto a polyester film on which aluminum had been vapor-deposited, and air-dried to form a charge generation layer with a thickness of 0.5 μm. Next, a charge transport layer forming coating liquid obtained by mixing 2 parts of compound (5), 2 parts of polycarbonate (Panlite L) and 45 parts of tetrahydrofuran was applied onto the charge generation layer using a doctor blade.
A photoreceptor of the present invention was prepared by drying at 0° C. for 30 minutes to form a charge generating layer having a thickness of 10μ. This photoreceptor-
The surface potential when 6.5KV corona charging is performed for 0.2 seconds is -790V, and the sensitivity EA is 3.9 Lux.
, sec.

[Effects of the Invention] The present invention has the above configuration, and when using it,
High sensitivity even in positive and negative charging, and
There is little deterioration of the photoconductor due to repeated use.

In addition, in practical use, it has excellent characteristics such as charge retention ability from low to high temperatures and from low humidity to high humidity, environmental friendliness with respect to sensitivity changes, and durability.

Claims (1)

[Scope of Claims] 1. An electrophotographic photoreceptor characterized by having a photosensitive layer containing at least one compound represented by the following general formula [I]. General formula [I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ However, in the formula, R_1 or R_2 is each independently an alkyl group, aryl group, or heterocyclic residue, and R_
1 and R_2 may form a heterocyclic residue. R_3
At least one of R_4, R_5 or R_6 is a substituent represented by general formula [II]. General formula [II] -SR_9 (In the formula, R_9 represents an alkyl group, an aralkyl group, or an aryl group that may have a substituent.) R_3, R_
4, R_5, or R_6 other than the substituents represented by the general formula [II] are each independently a hydrogen atom, a halogen atom, an alkyl group, or an alkoxy group. R_7
or R_8 is each independently an alkyl group, an aralkyl group, an aryl group, or a heterocyclic residue;
7 and R_8 may form a heterocyclic residue. n is 0
or 1.