JPH1184696A - Electrophotographic photoreceptor - Google Patents

Abstract

(57) [Abstract] [Problem] To be excellent in electrophotographic properties, and to reduce light fatigue,
Further, the present invention provides an organic electrophotographic photosensitive member having a long pot life of a coating solution for a photosensitive layer and good productivity. Kind Code: A1 An electrophotographic photoreceptor containing a mixture of specific hydrazone compounds, butadiene compounds, and styryl compounds as charge transport substances in a photosensitive layer containing an organic material as a main component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member having a photosensitive layer containing an organic photoconductive material on a conductive substrate and used in an electrophotographic printer, a copying machine, a facsimile and the like. About.

[0002]

2. Description of the Related Art Conventionally, an electrophotographic photosensitive member has a photosensitive layer made of an inorganic photoconductive material such as selenium or a selenium alloy.
Alternatively, an inorganic photoreceptor having a photosensitive layer made of a material in which an inorganic photoconductive substance such as zinc oxide or cadmium sulfide is dispersed in a resin binder has been mainly used. Due to advantages such as properties and film forming properties, an organic photoreceptor having a photosensitive layer made of an organic material including an organic photoconductive material has been developed. For example, a photoconductor provided with a photoconductive layer composed of poly-N-vinylcarbazole and 2,4,7-trinitrofluoren-9-one (US Pat. No. 348)
No. 4237), a photoreceptor containing an organic pigment as a main component (described in JP-A-47-37543), and a photoreceptor having a photoreceptor layer containing a eutectic complex composed of a dye and a resin as a main component (Described in JP-A-47-10785).

The photoreceptor has a function of retaining surface charges in a dark place, a function of receiving light to generate charge carriers,
Similarly, a function of receiving light and transporting charge carriers is required. A so-called single-layer type photoreceptor having a single photosensitive layer having these functions, and a charge carrier mainly for photoreception. A so-called function-separated multi-layered photosensitive system comprising a photosensitive layer in which a functionally separated layer is stacked on a layer contributing to generation and a layer contributing to the retention of surface charge in a dark place and the transport of charge carriers during photoreception. There is a body.

In recent years, a function-separated laminated type photoreceptor has become mainstream. Among them, a layer in which an organic pigment is used as a charge-generating substance and a coating solution in which a pigment is dispersed in a resin binder together with a solvent is applied. The layer formed as a charge generation layer, a coating liquid in which a low-molecular organic compound is dispersed in a resin binder together with a solvent as a charge transport material is applied, and the layer formed as a charge transport layer is laminated with a photosensitive layer. Many negatively charged photoconductors have been proposed.

For example, organic pigments such as phthalocyanine pigments, azo pigments, anthantrone pigments, perylene pigments, perinone pigments, squarylium pigments, thiapyrylium pigments, and quinacridone pigments are known as charge generation substances. Further, as the charge transporting substance, low-molecular organic compounds such as pyrazoline compounds, pyrazolone compounds, hydrazone compounds, oxadiazole compounds, arylamine compounds, benzidine compounds, styryl compounds, and butadiene compounds are known.

[0006]

Among the above-mentioned organic charge transporting materials, the hydrazone compound is a charge transporting material having excellent characteristics such as sensitivity and residual potential.
No. 66, for example. However, a photoreceptor using a hydrazone compound generally deteriorates due to light fatigue of the hydrazone compound when left in the light, and causes problems such as a decrease in charge potential and an increase in residual potential. Further, a coating solution containing a hydrazone compound and using a chlorine-based solvent such as methylene chloride as a solvent has a short pot life, which is one of the causes of deteriorating photoconductor productivity. This is not an exception in the case of a photoconductor using o-methyl-p-dibenzylaminobenzaldehyde- (diphenylhydrazone) represented by the structural formula (I).

[0007] The butadiene compound is a charge transporting substance which can provide a photoreceptor with little light fatigue and a good pot life of a coating solution, and is disclosed in Japanese Patent Publication No. Hei 5-19701. However, butadiene compounds have problems such as lowering the charge (JP-A-1-118845), and 1,1-bis (p-dimethylaminophenyl) -4,4 represented by the aforementioned structural formula (II). The photoreceptor using -diphenyl-1,3-butadiene is no exception.

[0008] A styryl compound is a charge transporting substance which is excellent in sensitivity and can provide a photoreceptor with less light fatigue, and is disclosed in Japanese Patent Publication No. 58-57744. However, since styryl compounds have poor solubility and compatibility with resins and solvents, they have problems such as insufficient dissolution and precipitation during film formation. The general formula (II)
A photoreceptor using 4-di- (p-triamino) -4 ′-[4- (di-p-triamino) styryl] stilbene, which is one of the compounds represented by I), is no exception.

Further, a photoreceptor using a mixture of a hydrazone compound and a butadiene compound as a charge transporting material,
Shows excellent properties against light fatigue.
No. 1 and other publications. Also, the pot life of the coating solution is excellent. However, this photoreceptor has low sensitivity when a small amount of a butadiene compound is used (Japanese Patent Laid-Open No. 6-674).
No. 43), there is a problem that a large amount causes a decrease in the charged position.

A photoreceptor using a mixture of a hydrazone compound and a styryl compound as a charge transporting material exhibits excellent characteristics against light fatigue, but has a disadvantage that the pot life of the coating solution is short. In addition, a photoreceptor using a mixture of a butadiene compound and a styryl compound as a charge transporting material has disadvantages in that it is difficult to add a large amount of a styryl compound and the charge is reduced.

The present invention has been made in view of the above-mentioned problems, and has excellent electrophotographic characteristics such as sensitivity, charge holding ability, residual potential, etc., has low light fatigue, and further has a photosensitive layer. An object of the present invention is to provide a photosensitive member having a long pot life of a coating solution and good productivity.

[0012]

According to the present invention, there is provided an electrophotographic photosensitive member having a photosensitive layer containing an organic photoconductive material on a conductive substrate. Containing a hydrazone compound represented by the following structural formula (I), a butadiene compound represented by the following structural formula (II), and a styryl compound represented by the following general formula (III) as charge transport materials The problem is solved by using a photoreceptor.

[0013]

Embedded image [In the formula (III), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R
⁶ represents an alkyl group having 1 to 4 carbon atoms, and may be the same as each other. By mixing and using the three types of compounds in this way, it is possible to make up for the drawbacks of using each of them alone, to provide excellent electrophotographic properties, to reduce light fatigue, and to further improve the photosensitive layer. A photoreceptor having a long pot life of the coating solution and good productivity can be obtained.

The mixing ratio of each compound is such that the hydrazone compound is in the range of 40% to 95% by weight of the total charge transporting substance,
Butadiene compound in the range of 1% by weight to 50% by weight,
It is desirable that the styryl compound be in the range of 4% by weight to 50% by weight. When the amount of the hydrazone compound is less than 40% by weight, there arises a problem that the deterioration in standing in the light increases and the pot life of the coating solution is shortened. When the amount of the butadiene compound exceeds 50% by weight, the problem of a large reduction in charge arises. When the amount is less than 1% by weight, the effect of improving the pot life of the coating liquid cannot be obtained.
When the amount of the styryl compound is less than 4% by weight, the effect of improving the sensitivity cannot be obtained, and when the amount exceeds 50% by weight, there arises a problem that the solubility of the coating solution becomes poor and the coating solution may be precipitated.

Specific examples of the compound represented by the general formula (III) include the following structural formulas (III-1) to (III-
The compound of the present invention is not limited thereto.

[0016]

Embedded image

[0017]

Embedded image

[0018]

FIG. 1 is a schematic cross-sectional view showing an example of the structure of a photoreceptor according to the present invention, in which a charge generating layer 4 and an undercoat layer 2 are provided on a conductive substrate 1. Charge transport layer 5
Is a negatively-charged function-separated layered photoconductor having a configuration in which a photosensitive layer 3a is sequentially laminated. FIG. 2 is a schematic cross-sectional view showing a different configuration example of the photoreceptor according to the present invention, in which a photosensitive layer 3b in which a charge transport layer 5 and a charge generation layer 4 are sequentially laminated on a conductive substrate 1 is provided. Further, it is a positively-charged, function-separated, laminated photoreceptor having a surface protective layer 6. FIG. 3 is a schematic cross-sectional view showing still another configuration example of the photoreceptor according to the present invention, in which a photosensitive layer 3c containing a mixture of a charge generating substance and a charge transporting substance is provided on a conductive substrate 1. In general, it is a positively-charged single-layer type photoreceptor having the above configuration.

The conductive substrate 1 functions as one electrode of the photosensitive member and serves as a support for each layer constituting the photosensitive member. The conductive substrate 1 may have any shape such as a cylindrical shape, a plate shape, and a film shape. In addition, a metal such as aluminum, stainless steel, nickel, or the like, or a material such as glass or resin which has been subjected to a conductive treatment may be used. The undercoat layer 2 is made of a layer mainly composed of a resin or a metal oxide film such as alumite. The undercoat layer 2 controls the injection of electric charge from the conductive substrate to the photosensitive layer. It is provided as needed for the purpose of improving the adhesiveness of the layer. The undercoat layer is made of polyethylene, polypropylene, polystyrene, acrylic resin, vinyl chloride resin, vinyl acetate resin, polyurethane resin, epoxy resin, polyester resin, melamine resin, silicon resin, polybutyral resin, polyamide resin, and copolymers thereof. And the like can be used alone or in appropriate combination as a mixture. Further, these resins may contain metal oxide fine particles and the like. As the metal oxide fine particles to be contained, SiO 2
₂ , TiO ₂ , In ₂ O ₃ , ZrO _{2 and the} like. The thickness of the undercoat layer can be arbitrarily set within a range that does not cause an adverse effect such as an increase in residual potential when used repeatedly and continuously, although it depends on the composition of the undercoat layer.

The charge generation layer 4 is a layer in which an organic charge generation substance is vacuum-deposited or a coating film of a material in which organic charge generation substance particles are dispersed in a resin binder, and has a function of receiving light and generating a charge. Have. In addition to the high charge generation efficiency, it is important to inject the generated charges into the charge transport layer, and it is desirable that the injection properties be low even in a low electric field with little dependence on the electric field. Since the charge generation layer only needs to have a charge generation function, its film thickness is determined by the light absorption coefficient of the charge generation material used, and is generally 5 μm or less, preferably 1 μm or less.
μm or less. The charge generation layer may be mainly composed of a charge generation substance and may be used by adding a charge transport substance thereto. As the charge generating substance, phthalocyanine pigments, azo pigments, anthrone pigments, perylene pigments, perinone pigments, squarylium pigments, thiapyrylium pigments, quinacridone pigments, and the like can be used alone or in appropriate combination and mixed. Examples of the resin binder include polycarbonate resin, polyester resin, polyamide resin, polyurethane resin, epoxy resin, polybutyral resin, vinyl chloride copolymer, phenoxy resin, silicone resin, methacrylic ester resin, and copolymers thereof. They can be used alone or in combination as appropriate.

The charge transport layer 5 is a coating film made of a material in which a charge transport material is dispersed in a resin binder. The charge transport layer 5 holds the charge of the photoreceptor as an insulator layer in a dark place. It has the function of transporting injected charges. As the charge transport material, in the present invention, a hydrazone compound represented by the structural formula (I), a butadiene compound represented by the structural formula (II), and a styryl compound represented by the general formula (III) are combined. Although they are used as a mixture, other charge transporting substances may be used in combination. Examples of charge transport materials used in combination include pyrazoline compounds, pyrazolone compounds, oxadiazole compounds, arylamine compounds, benzidine compounds, stilbene compounds, hydrazone compounds and styryl compounds other than the above, and charge transport polymers such as polyvinylcarbazole. Can be used. Polycarbonate resin, polyester resin,
Polystyrene resin, methacrylic acid ester polymers and copolymers are used. Stability of mechanical, chemical and electrical properties, adhesion, and compatibility with charge transport materials are important. . The thickness of the charge transport layer is 3 μm to 50 μm in order to maintain a practically effective surface potential.
m is preferable, and more preferably, 10 μm to 40 μm.
m.

The single-layer type photosensitive layer is a coating film of a material in which a charge generating substance and a charge transporting substance are dispersed in a resin binder. The materials used for the charge generating layer 4 and the charge transporting layer 5 are similarly used. It is possible. In order to maintain a practically effective surface potential, the film thickness is 3 μm to 50 μm.
μm is preferable, and more preferably, 10 μm to 40 μm.
It is in the range of μm.

The photosensitive layers 3a, 3b, 3c as described above may be provided, if necessary, for the purpose of improving the sensitivity, reducing the residual potential, or reducing the characteristic fluctuation during repeated use.
An electron accepting substance can be contained. Examples of the electron accepting substance include succinic anhydride, maleic anhydride, dibromo succinic anhydride, phthalic anhydride, 3-nitrophthalic anhydride,
4-nitrophthalic anhydride, pyromellitic anhydride, pyromellitic acid, trimellitic acid, trimellitic anhydride, phthalimide, 4-nitrophthalimide, tetracyanoethylene, tetracyanodimethane, chloranil, bromanyl, o-nidrobenzoic acid And compounds having a high electron affinity.

Further, the photosensitive layer may contain a deterioration inhibitor such as an antioxidant or a light stabilizer for the purpose of improving environmental resistance and stability against harmful light. Compounds used for such purposes include chromal derivatives such as tocopherol and etherified or esterified compounds thereof, polyarylalkane compounds, hydroquinone derivatives and etherified or dietherified compounds thereof, benzophenone derivatives,
Examples include benzotriazole derivatives, thioetherified compounds, phenylenediamine derivatives, phosphonic acid esters, phosphite esters, phenol compounds, hindered phenol compounds, linear amine compounds, cyclic amine compounds, hindered amine compounds, and the like.

The surface protective layer 6 is provided as necessary, and is made of a material which is excellent in durability against mechanical stress and is chemically stable. In a dark place, the surface protective layer 6 receives a charge due to corona discharge or the like. It has the function of holding, and has the ability to transmit light that the charge generation layer is sensitive to, transmitting light at the time of exposure of the photoreceptor to reach the charge generation layer, and receiving the generated charge It is necessary to neutralize and eliminate surface charges. As described above, the constituent material of the surface protective layer is desirably as transparent as possible in the wavelength region where the light absorption maximum of the charge generation substance is maximum. Examples of the material constituting the surface protective layer include modified silicone resins such as acrylic modified silicone resin, epoxy modified silicone resin, alkyd modified silicone resin, polyester modified silicone resin, and urethane modified silicone resin. Silicon resin or the like can also be applied. These materials can be used alone, but also include SiO 2
It is preferable to use a mixture of a condensate of a metal alkoxy compound having a film-forming property mainly composed of ₂ , TiO ₂ , In ₂ O ₃ , and ZrO ₂ , because durability is further improved.
The thickness of the surface protective layer depends on the composition of the constituent materials, but can be set arbitrarily within a range that does not adversely affect the characteristics of the photoreceptor, such as an increase in residual potential when used repeatedly and continuously.

The photoreceptor is manufactured by sequentially laminating each layer as described above on a conductive substrate according to the constitution. Each layer is formed by applying and drying a coating solution obtained by dispersing and dissolving each constituent material in an appropriate organic solvent by a usual method such as a dip coating method. In addition, the charge generation layer depends on the charge generation material used.
It can also be formed by a vacuum evaporation method.

[0027]

Embodiments of the present invention will be described below.
In the examples, "part" indicates "part by weight" and "%" indicates "% by weight". Example 1 An alcohol-soluble polyamide (manufactured by Toray Industries, Inc.) was provided on the outer peripheral surface of an aluminum cylinder having an outer diameter of 30 mm and a length of 120 mm.
A solution obtained by dispersing and dissolving 5 parts of titanium oxide fine particles treated with aminosilane and 5 parts of titanium oxide fine particles in a mixed solvent of methanol and methylene chloride (mixing ratio: 6/4) is applied by dip coating at a temperature of 100 ° C. And dried for 30 minutes.
m was formed.

On the undercoat layer, a CuKα-X-ray diffraction spectrum as a charge generating substance showed a Bragg angle of 7.22.
°, 9.60 °, 11.60 °, 13.40 ° 14.8
8 °, 18.34 °, 23.62 °, 24.14 °, 2
It has a clear diffraction peak at 7.32 ° and 9.60
1 part of titanyloxyphthalocyanine (described in Japanese Patent Application No. Hei 6-289363) having the maximum diffraction peak at 0 ° and a vinyl chloride copolymer resin as a resin binder (manufactured by Zeon Corporation; trade name “MR-110”) 1) and a solution prepared by dispersing and dissolving 1 part in 98 parts of methylene chloride was applied by dip coating, and dried at 100 ° C. for 30 minutes to form a charge generating layer having a thickness of 0.3 μm.

On this charge generating layer, a hydrazone compound represented by the above structural formula (I) as a charge transport material (manufactured by
7 parts, butadiene compound represented by the structural formula (II) (manufactured by Annan; product name: CTC191);
1 part of trade name "T405"), structural formula (III-2)
A polycarbonate resin (manufactured by Teijin Chemicals Ltd .; a product name "K")
1300 ") and a solution dispersed and dissolved in 90 parts of methylene chloride was applied by dip coating and dried at a temperature of 100 ° C. for 30 minutes to form a charge transport layer having a thickness of 20 μm. Produced.

Example 2 In Example 1, except that the styryl compound represented by the structural formula (III-2) as the charge transport material was changed to the styryl compound represented by the structural formula (III-4), A photoconductor was produced in the same manner as in Example 1. Example 3 Example 1 was the same as Example 1 except that the styryl compound represented by the structural formula (III-2) as the charge transport material was changed to the styryl compound represented by the structural formula (III-6). A photoreceptor was produced in the same manner as described above.

Comparative Example 1 The procedure of Example 1 was repeated except that the butadiene compound and the styryl compound were not used as the charge transporting substance, and only 10 parts of the hydrazone compound represented by the structural formula (I) was used.
A photoconductor was produced in the same manner as in Example 1. Comparative Example 2 The same method as in Example 1 except that the hydrazone compound and the styryl compound were not used as the charge transport material, and the structural formula (II) was used.
A photoreceptor was prepared in the same manner as in Example 1, except that only 10 parts of the butadiene compound shown in (1) was used.

Comparative Example 3 In Example 1, the hydrazone compound and the butadiene compound were not used as the charge transporting substance, and the compound represented by the structural formula (II)
A photoconductor was prepared in the same manner as in Example 1, except that only 10 parts of the styryl compound shown in I-2) was used.

Comparative Example 4 In Example 1, 9 parts of the hydrazone compound represented by the structural formula (I) and 1 part of the butadiene compound represented by the structural formula (II) were used without using the styryl compound as the charge transporting substance. A photoconductor was prepared in the same manner as in Example 1, except for the above. Comparative Example 5 In Example 1, 8 parts of the hydrazone compound represented by the structural formula (I) and 2 parts of the styryl compound represented by the structural formula (III-2) were used without using the butadiene compound as the charge transporting substance. A photoconductor was prepared in the same manner as in Example 1 except for the above.

Comparative Example 6 In Example 1, 8 parts of the butadiene compound represented by the structural formula (II) and 2 parts of the styryl compound represented by the structural formula (III-2) were used without using the hydrazone compound as the charge transporting substance. A photoconductor was prepared in the same manner as in Example 1, except for the following.

With respect to each of the photoconductors manufactured as described above, the initial electrical characteristics and light fatigue characteristics were evaluated using a photoconductor drum electrical characteristic evaluation apparatus. The electrical characteristics were measured by mounting the photoreceptor on an evaluation device, charging the surface of the photoreceptor to about -650 V in a dark place by corona discharge using a corotron method, measuring the charged potential V _0, and then measuring the corona discharge. Was stopped and left in a dark place for 5 seconds, and the surface potential V _D5 was measured to determine the potential holding ratio V _K5 [((V ₀ −V _D5 ) / V ₀ ) × 100]. Similarly, the charged potential V ₀ of the photoreceptor surface is about −65.
Charged to 0 V, wavelength 780 nm, 1 μW / c
By irradiating m ² light, the exposure amount E ₁₀₀ (sensitivity) for attenuating the charged potential on the surface from about −650 V to −100 V was measured. Further, light having a wavelength of 780 nm and 1 μW / cm ²
The charge potential upon irradiation for 2 seconds was measured and defined as residual potential _VR5 . Table 1 shows the measurement results.

[0036]

[Table 1] The light fatigue characteristics are evaluated by irradiating the surface of the photoreceptor with 1500 lux · s fluorescent lamp light for 10 minutes, and measuring the dark portion potential and the light portion potential immediately before and after using a photoreceptor drum electrical characteristic evaluation apparatus. It mounted photoreceptor evaluation apparatus to measure the dark potential V _D by charging the photosensitive member surface while rotating the photosensitive member to be about -600 V, followed by the wavelength 780 nm,
By irradiating with light of 1 μW / cm ² for 0.25 seconds, the light potential V
Measure _L. Such a measurement was performed immediately before and after the irradiation of the fluorescent light, and the light fatigue property was evaluated based on the fluctuation of the measured value. Table 2 shows the measurement results.

[0037]

[Table 2] As can be seen from Tables 1 and 2, the photoreceptor of Comparative Example 1 using only a hydrazone compound as the charge transporting substance has a lower sensitivity and a higher residual potential than the respective photoreceptors of the examples, In the fatigue, the bright portion potential is greatly increased and the sensitivity is almost lost. The photoreceptor of Comparative Example 2 using only the butadiene compound has a low potential holding ratio and a low dark portion potential. In Comparative Example 3 using only the styryl compound,
The solubility and compatibility of the styryl compound in the coating solution for the charge transport layer were poor, so that the styryl compound was deposited during coating and a good coating film could not be formed, and a photoreceptor could not be produced. Furthermore, the photoreceptor of Comparative Example 4 in which no styryl compound was used had a very low sensitivity, a large residual potential, and a large bright portion potential. The photoreceptor of Comparative Example 5 has good initial characteristics and light fatigue characteristics, but has a problem in the pot life of the coating solution as described later. The photoreceptor of Comparative Example 6 has a low potential holding ratio and a large fluctuation in dark portion potential due to light fatigue.

Next, with respect to the pot life of the coating solution for the charge transport layer, the coating solution immediately after the preparation of each coating solution for the charge transport layer from Example 1 to Comparative Example 6 was prepared at a temperature of 23 ° C. and a relative humidity of 50%. Each of the photoconductors was prepared in the same manner as in Example 1 to Comparative Example 6 using the coating solution left for two months in the dark in the environment described above, and the electrical characteristics of each of these photoconductors were measured as described above. It was evaluated by measuring and comparing. Table 3 shows the evaluation results.

[0039]

[Table 3] As shown in Table 3, the coating solution for the charge transport layer of Comparative Example 1 using only the hydrazone compound as the charge transport material and the coating solution for the charge transport layer of Comparative Example 5 using no butadiene compound were left in the dark. The sensitivity is almost gone,
The residual potential becomes extremely large. In the charge transport layer coating liquid of Comparative Example 4, the sensitivity is lowered. Also, with the coating solution for the charge transport layer of Comparative Example 3 using only the styryl compound, no photoconductor could be prepared from the beginning.

From the above results, the photoreceptor using the charge transport material according to the present invention has excellent sensitivity, charge retention ability, small residual potential, very little light fatigue, and the charge transport layer coating solution. The pot life is also good. The effect of the present invention is clear.

[0041]

According to the present invention, there is provided an electrophotographic photoreceptor having a photosensitive layer containing an organic photoconductive material on a conductive substrate, wherein the photosensitive layer has the above-mentioned structural formula A hydrazone compound represented by (I), a butadiene compound represented by the structural formula (II), and a styryl compound represented by the general formula (III) are mixed and contained to prepare a photoconductor. By using the charge transport material combined in this way, the electrical characteristics such as sensitivity, charge retention ability, residual potential, etc. are good, and there is little light fatigue, and the pot life of the coating solution for the photosensitive layer is long, and the productivity is high. And an excellent photoconductor can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing one configuration example of a photoreceptor according to the present invention.

FIG. 2 is a schematic cross-sectional view showing a different configuration example of a photoconductor according to the present invention.

FIG. 3 is a schematic cross-sectional view showing still another configuration example of the photoreceptor according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conductive substrate 2 Undercoat layer 3a, 3b, 3c Photosensitive layer 4 Charge generation layer 5 Charge transport layer 6 Surface protective layer

Claims (3)

[Claims] 1. An electrophotographic photoreceptor having a photosensitive layer containing an organic photoconductive material on a conductive substrate, wherein the charge transport material in the photosensitive layer is represented by the following structural formula (I). An electrophotographic photoreceptor comprising a hydrazone compound, a butadiene compound represented by the following structural formula (II), and a styryl compound represented by the following general formula (III). Embedded image [In the formula (III), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R
⁶ represents an alkyl group having 1 to 4 carbon atoms, and may be the same as each other. ] 2. The charge transport material contained in the photosensitive layer, wherein the content of the hydrazone compound represented by the structural formula (I) is in the range of 40% by weight to 95% by weight of the total charge transport material. When the content of the butadiene compound represented by the structural formula (II) is in the range of 1% by weight to 50% by weight of the total charge transporting material, the content of the styryl compound represented by the general formula (III) is 4% to 50% by weight
2. The electrophotographic photoconductor according to claim 1, wherein 3. The method according to claim 1, wherein the charge generating substance contained in the photosensitive layer is C
In the uKα-X-ray diffraction spectrum, the Bragg angle was 7.22 °,
9.60 °, 11.60 °, 13.40 ° 14.88
°, 18.34 °, 23.62 °, 24.14 °, 2
It has a clear diffraction peak at 7.32 ° and 9.60
3. The electrophotographic photoconductor according to claim 1, wherein the photoconductor is titanyloxyphthalocyanine having a maximum diffraction peak of .degree.