JPH11282178A - Electrophotographic photoreceptor - Google Patents

Abstract

(57) [Summary] (with correction) [PROBLEMS] To obtain a positively charged electrophotographic photoreceptor which does not generate ozone and has excellent sensitivity characteristics by optimizing a combination of a charge generating substance and a charge transporting substance. The compound represented by the general formula (I) wherein the photosensitive layer is a charge transport material
And an azo compound represented by the chemical formula (VI), which is a charge generating substance. (In the above formula, A ₁ , A ₂ , A ₃ , and A ₄ are a pyridyl group, an alkylpyridyl group, an alkoxypyridyl group, or a halogenated pyridyl group bonded at the 2-position, and R ₁ and R ₂ are a hydrogen atom, an alkyl group, an alkoxy group. Represents a group or a halogen atom.)

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positively charged electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor having good compatibility between a charge generating substance and a charge transporting substance.

[0002]

2. Description of the Related Art In the electrophotographic system based on the invention of Carlson, the surface of a photoreceptor is charged, an electrostatic latent image is formed by exposure, developed with toner to form a visible image, and then the visible image is formed on paper or the like. Transcribe. The residual toner adhered to the photoconductor is removed, and after the charge is removed, the charging process is repeated again.

[0003] Such a photoreceptor has good charge characteristics, charge retention characteristics in a dark place, and charge dissipating property (half-attenuation exposure amount / sensitivity) after light irradiation. It is necessary to have good durability and durability against environmental changes during use. More recently, it has been required that the amount of ozone generated in the charging step be small in consideration of the effect on the human body.

Conventionally, an inorganic electrophotographic photosensitive member containing an inorganic photoconductive material such as selenium, zinc oxide, and cadmium sulfide as a main component has been widely used as an electrophotographic photosensitive member. In recent years, a photoconductor using an organic photoconductive material has been actively developed for an inorganic electrophotographic photoconductor and has already been put to practical use. Organic photoreceptors are more flexible than inorganic photoreceptors,
It attracts attention because of its excellent properties such as thermal stability, film formation, light weight, cost, and productivity.

For example, Japanese Patent Publication No. Sho 50-10496 discloses a photoreceptor containing poly-N-vinylcarbazole and 2,4,7-trinitro-9-fluorenone.
No. 25658 proposes a photoconductor in which poly-N-vinylcarbazole is sensitized with a pyrylium dye. However, these photoreceptors were not always sufficient in terms of sensitivity and durability.

Then, a so-called function-separated type photoconductor (laminated type) in which a charge generation layer and a charge transport layer are separated has been proposed. Photoreceptors have been proposed. By separating the functions of the photosensitive layer into different layers of the charge generation layer and the charge transport layer, materials having various characteristics can be combined, and a photosensitive member having high sensitivity and good durability can be obtained. It is expected.

At present, most of the organic photoconductors are used as a negative charging type in which the surface of the photoconductor is charged to a negative potential. This is because many of the charge transport materials currently being developed are hole transport materials rather than electron transport, and these charge transport materials are suitable for use in functionally separated photoreceptors.

[0008]

However, the negatively charged photosensitive member has the following problems in practical use. That is,
A negatively charged photoreceptor is likely to generate ozone when charged by a charger, and has environmental health problems. A negatively charged photoreceptor requires a positively charged toner for development, but the positively charged toner is more difficult to manufacture than a negatively charged toner.

In order to solve the above-mentioned problems, a positively charged photosensitive member is used. As a positively charged photoreceptor, for example, a lamination type in which a charge transport layer and a charge generation layer are sequentially laminated on a substrate is known, and this type of electrophotographic photoreceptor has a thin charge generation layer. Is the outermost layer and has poor durability. In addition to the above, a single-layer photoreceptor containing a charge generating substance and a charge transporting substance in a single photosensitive layer on a substrate is also considered as a positively charged photoreceptor. If the matching of the combination is not good, the required sensitivity cannot be obtained.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide a positively charged electrophotographic photosensitive member which does not generate ozone and has excellent sensitivity characteristics by optimizing a combination of a charge generating material and a charge transporting material. To provide.

[0011]

According to the present invention, there is provided an electrophotographic photosensitive member having a photosensitive layer on a conductive substrate according to the present invention.
And a charge-generating substance, an azo compound represented by the chemical formula (VI).
The benzidine compound represented by I) and the azo compound represented by the chemical formula (VI) as a charge-generating substance must be contained. A benzidine compound represented by the general formula (IV) and an azo compound represented by the chemical formula (VI) which is a charge generating substance, or a benzidine compound represented by the general formula (V) and a charge generating substance This is achieved by including an azo compound represented by the chemical formula (VI).

[0012]

Embedded image (In the above formula, A ₁ , A ₂ , A ₃ , and A ₄ each represent a pyridyl group, an alkylpyridyl group, an alkoxypyridyl group, or a halogenated pyridyl group bonded at the 2-position, and R ₁ and R ₂ represent a hydrogen atom and an alkyl group, respectively. , An alkoxy group or a halogen atom.)

[0013]

Embedded image(In the above formula, A₁, A_Two, A_ThreeBind at position 2
Pyridyl group, alkylpyridyl group, alkoxypyridyl
Group or halogenated pyridyl group, B₁Is an aryl group,
Alkylaryl group, alkoxyaryl group, halogen
Aryl group, R ₁, R_TwoAre hydrogen and alkyl
Represents a group, an alkoxy group or a halogen atom. )

[0014]

Embedded image (In the above formula, A ₁ and A ₂ each represent a pyridyl group, an alkylpyridyl group, an alkoxypyridyl group or a halogenated pyridyl group bonded at the 2-position, and B ₁ and B ₂ represent an aryl group, an alkylaryl group, an alkoxyaryl group or a halogen. Aryl group, R ₁ and R ₂ each represent a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom.)

[0015]

Embedded image (In the above formula, A ₁ and A ₂ each represent a pyridyl group, an alkylpyridyl group, an alkoxypyridyl group or a halogenated pyridyl group bonded at the 2-position, and B ₁ and B ₂ represent an aryl group, an alkylaryl group, an alkoxyaryl group or a halogen. Aryl group, R ₁ and R ₂ each represent a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom.)

[0016]

Embedded image (In the above formula, A ₁ represents a pyridyl group, an alkylpyridyl group, an alkoxypyridyl group or a halogenated pyridyl group bonded at the 2-position, and B ₁ , B ₂ and B ₃ represent an aryl group, an alkylaryl group, an alkoxyaryl group or a halogenated group. An aryl group, R ₁ and R ₂ each represent a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom.)

[0017]

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[0018]

FIG. 1 is a sectional view showing an electrophotographic photosensitive member according to the present invention. An undercoat layer 2 and a photosensitive layer 6 are laminated on a conductive substrate 1. The photosensitive layer 6 includes a charge generating substance, a charge transporting substance, and a binder. The electrophotographic photoreceptor of the present invention can be produced by dissolving a charge transporting substance and a binder in a solvent and further dispersing the charge generating substance, coating a coating liquid on a conductive substrate and drying.

Among the benzidine compounds which are charge transporting substances, specific examples of the compound represented by the general formula (I) are represented by chemical formulas 1 to 7, and specific examples of the compound represented by the general formula (II) are represented by chemical formulas 8 to 14; Specific examples of the compound represented by (III) are Chemical Formulas 15 to 21, specific examples of the compound represented by General Formula (IV) are Chemical Formulas 22 to 28, and specific examples of the compound represented by General Formula (V) are Chemical Formulas 29 to 35.

[0020]

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[0050]

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[0051]

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[0052]

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[0053]

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[0054]

Embedded image An azo compound represented by the chemical formula (VI) is used as the charge generating substance.

[0055]

Embedded image As the conductive substrate, a sheet, belt, or cylindrical shape of a metal such as iron, nickel, copper, or aluminum, a plastic film on which metal is deposited, or a conductive plastic is used. If necessary, a conductive subbing layer or a barrier layer can be provided on these substrates.

Binders include polyvinyl formal resin, polyvinyl acetal resin, polyvinyl butyral resin, phenoxy resin, polyester resin polycarbonate resin, epoxy resin, melamine resin, polysulfone resin, polyketone resin, acrylic resin, styrene resin,
A vinyl chloride copolymer or the like is used. The photoreceptor of the present invention has a hindered phenol,
Antioxidants such as phosphorous acid type and light stabilizers such as hindered amine can be used.

Additives such as surfactants can be used to stably coat the photosensitive layer and improve the coated surface. The thickness of the photosensitive layer is 10 to 40 μm, preferably 15 to 30 μm. The total amount of the charge transport material in the photosensitive layer is 20 to 80% by weight based on the total solids in the photosensitive layer.
Preferably it is 30 to 70% by weight. The amount of the charge generating substance in the photosensitive layer is from 0.1 to 20% by weight, preferably from 0.5 to 5% by weight, based on the total solid content in the photosensitive layer.

[0058]

The present invention will be described more specifically below. “Parts” in the examples means “parts by weight”. Example 1 A 30 mm × 30 mm × 1 mm aluminum plate was used as a conductive substrate. A coating solution prepared by dissolving 4.5 parts of a nylon resin (“Amilan CM8000” manufactured by Toray Co., Ltd.) in a mixed solvent of 130 parts of methanol and 20 parts of 1-butanol was applied by dipping and dried at 100 ° C. for 20 minutes. An undercoat layer of 1 μm was provided.

Next, as a charge transport material, the above-mentioned chemical formula 2
Are dissolved in 45 parts of tetrahydrofuran by dissolving 5 parts of a benzidine compound, 5 parts of a polycarbonate resin (“PANLITE TS2050” manufactured by Teijin Chemicals), and 0.3 parts of BHT.
To this solution, 0.5 parts of an azo pigment represented by the chemical formula (VI) was added and dispersed by a ball mill for 18 hours. This dispersion was applied on the undercoat layer by a wire bar method, and dried at 110 ° C. for 60 minutes to provide a 22 μm photosensitive layer. Thus, a single-layer type electrophotographic photoreceptor was produced. Example 2 A single-layer electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the benzidine compound represented by Chemical Formula 10 was used instead of the benzidine compound represented by Chemical Formula 2. Example 3 A single-layer type electrophotographic photoconductor was prepared in the same manner as in Example 1, except that the benzidine compound represented by Chemical Formula 18 was used instead of the benzidine compound represented by Chemical Formula 2. Example 4 A single-layer type electrophotographic photoconductor was prepared in the same manner as in Example 1, except that the benzidine compound represented by Chemical Formula 26 was used instead of the benzidine compound represented by Chemical Formula 2. Example 5 A single-layer type electrophotographic photoconductor was prepared in the same manner as in Example 1, except that the benzidine compound represented by Chemical Formula 34 was used instead of the benzidine compound represented by Chemical Formula 2. Comparative Example 1 The chemical formula (VII) was used instead of the benzidine compound shown in Chemical Formula 2.
A single-layer type electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the compound shown in (1) was used.

[0060]

Embedded image Comparative Example 2 The chemical formula (VII) was used instead of the benzidine compound shown in Chemical Formula 2.
A single-layer type electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the compound shown in I) was used.

[0061]

Embedded image Next, the half-attenuation exposure amount (sensitivity) of the produced single-layer type electrophotographic photoreceptor was measured. Furthermore, the repetition characteristics of the charged potential and the residual potential were measured. These measurements were performed using the electrostatic charging tester EPA8100 (manufactured by Kawaguchi Electric Works).
Was used. Corona discharge was performed at +6 kV for 10 seconds to charge, and then exposure was performed with white light having an illuminance of 2 lx to determine a half-attenuation exposure amount. The residual potential was defined as the surface potential of the electrophotographic photoreceptor after irradiating with white light at 2 lx for 10 seconds. Table 1 shows the measurement results.

[0062]

[Table 1] As shown in Table 1, the electrophotographic photoreceptor of the present invention has a good half-attenuation exposure amount, and also has good potential stability (durability) in repetition characteristics.

[0063]

According to the present invention, in an electrophotographic photosensitive member having a photosensitive layer on a conductive substrate, the photosensitive layer is a benzidine compound represented by the general formula (I), which is a charge transporting substance, and a charge generating substance. Including the azo compound represented by the chemical formula (VI), the benzidine compound represented by the general formula (II) and the azo compound represented by the chemical formula (VI) which is a charge generating substance, and represented by the general formula (III) It must contain a benzidine compound and an azo compound represented by the chemical formula (VI) which is a charge generating substance, and must contain a benzidine compound represented by the general formula (IV) and an azo compound represented by the chemical formula (VI) which is a charge generating substance , Or a benzidine compound represented by the general formula (V) and an azo compound represented by the chemical formula (VI), which is a charge generating substance, so that the compatibility between the charge transporting substance and the charge generating substance is good. There sensitivity and excellent durability positively charged electrophotographic photoreceptor is obtained on no generation.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an electrophotographic photoconductor of the present invention.

[Explanation of symbols]

 Reference Signs List 1 conductive substrate 2 undercoat layer 6 photosensitive layer

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[Procedure amendment]

[Submission date] April 15, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0056

[Correction method] Change

[Correction contents]

As the binder, polyvinyl formal resin, polycarbonate resin, polyvinyl butyral resin, phenoxy resin, polyester resin, polycarbonate resin, epoxy resin, melamine resin, polysulfone resin, polyketone resin, acrylic resin, styrene resin, vinyl chloride resin A polymer or the like is used. In the photoreceptor of the present invention, an antioxidant such as a hindered phenol or a phosphorous acid and a light stabilizer such as a hindered amine can be used to stabilize the characteristics.

Claims (5)

[Claims] 1. An electrophotographic photoreceptor comprising a photosensitive layer on a conductive substrate, wherein the photosensitive layer comprises a benzidine compound represented by the general formula (I) as a charge transporting substance and a chemical formula (VI) as a charge generating substance. An electrophotographic photoreceptor comprising the azo compound shown below. Embedded image (In the above formula, A ₁ , A ₂ , A ₃ , and A ₄ each represent a pyridyl group, an alkylpyridyl group, an alkoxypyridyl group, or a halogenated pyridyl group bonded at the 2-position, and R ₁ and R ₂ represent a hydrogen atom and an alkyl group, respectively. , An alkoxy group or a halogen atom.) 2. An electronic photograph comprising a photosensitive layer on a conductive substrate.
General formula in which the photosensitive layer is a charge transport material in a true photoreceptor
Benzidine compound shown in (II) and charge generation substance
An electronic device comprising an azo compound represented by the formula (VI):
Photoconductor for child photography. Embedded image(In the above formula, A₁, A_Two, A_ThreeBind at position 2
Pyridyl group, alkylpyridyl group, alkoxypyridyl
Group or halogenated pyridyl group, B₁Is an aryl group,
Alkylaryl group, alkoxyaryl group, halogen
Aryl group, R ₁, R_TwoAre hydrogen and alkyl
Represents a group, an alkoxy group or a halogen atom. ) 3. An electrophotographic photoreceptor comprising a photosensitive layer on a conductive substrate, wherein the photosensitive layer comprises a benzidine compound represented by the general formula (III) as a charge transporting substance and a chemical formula (VI) as a charge generating substance. An electrophotographic photoreceptor comprising the azo compound shown below. Embedded image (In the above formula, A ₁ and A ₂ each represent a pyridyl group, an alkylpyridyl group, an alkoxypyridyl group or a halogenated pyridyl group bonded at the 2-position, and B ₁ and B ₂ represent an aryl group, an alkylaryl group, an alkoxyaryl group or a halogen. Aryl groups, R ₁ and R ₂ each represent a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom.) 4. An electrophotographic photoreceptor comprising a photosensitive layer on a conductive substrate, wherein the photosensitive layer comprises a benzidine compound represented by the general formula (IV) as a charge transporting substance and a chemical formula (VI) as a charge generating substance. An electrophotographic photoreceptor comprising the azo compound shown below. Embedded image (In the above formula, A ₁ and A ₂ each represent a pyridyl group, an alkylpyridyl group, an alkoxypyridyl group or a halogenated pyridyl group bonded at the 2-position, and B ₁ and B ₂ represent an aryl group, an alkylaryl group, an alkoxyaryl group or a halogen. Aryl groups, R ₁ and R ₂ each represent a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom.) 5. An electrophotographic photoreceptor comprising a photosensitive layer on a conductive substrate, wherein the photosensitive layer is a benzidine compound represented by the general formula (V) as a charge transporting substance and a chemical formula (VI) as a charge generating substance. An electrophotographic photoreceptor comprising the azo compound shown below. Embedded image (In the above formula, A ₁ represents a pyridyl group, an alkylpyridyl group, an alkoxypyridyl group or a halogenated pyridyl group bonded at the 2-position, and B ₁ , B ₂ and B ₃ represent an aryl group, an alkylaryl group, an alkoxyaryl group or a halogenated group. The aryl group, R ₁ and R ₂ each represent a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom.