JP3086367B2 - Organic photoconductive material and electrophotographic photoreceptor using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic photoconductive material and an electrophotographic photosensitive member using the same, and more particularly, to an electrophotographic photosensitive member provided with a photosensitive layer containing a specific hydrazone compound.

[0002]

2. Description of the Related Art In recent years, the use of electrophotography is not limited to the field of copying machines, but has spread to fields in which photographic technology was conventionally used, such as printing plates, slide films, and microfilms. Application to a high-speed printer using a light source is also being studied. Recently, the use of a photoconductive material other than an electrophotographic photosensitive member, for example, an application to an electrostatic recording element, a sensor material, an EL element, and the like has begun to be studied. Accordingly, demands for photoconductive materials and electrophotographic photoreceptors using the same are becoming higher and wider.
So far, what has been used as an electrophotographic photoreceptor material,
Inorganic materials such as amorphous selenium, cadmium sulfide, and zinc oxide have been proposed. In organic materials, poly-N-vinylcarbazole and other photoconductive polymers and various low-molecular photoconductive materials have been proposed.

[0003]

Although a photoreceptor using the above-mentioned inorganic substance is useful, it is not always satisfactory in sensitivity, heat stability, moisture resistance and durability.
In particular, amorphous selenium and cadmium sulfide have problems in terms of production and handling due to toxicity. Further, the above-mentioned photoconductive polymer such as poly-N-vinylcarbazole has insufficient film-forming properties and flexibility, and causes a problem of cracking or peeling when left as a film. To compensate for these drawbacks, a plasticizer or a binder is added, but although this improves the flexibility, the drawback is that electrical properties such as sensitivity and residual potential are reduced. It was extremely difficult. On the other hand, a low-molecular photoconductive substance does not itself have a film forming ability, but can form a film by appropriately selecting a polymer binder, and has excellent film forming properties and flexibility. A photoreceptor can be obtained. In recent years, a method has been actively proposed in which two functions of the photoconductive substance, that is, generation and transport of carriers are performed by different organic compounds, respectively. In many cases, the carrier transporting substance is a low molecular organic compound, which has a function such as high charging ability, high potential holding power, high photosensitivity, and almost no residual potential, and can be selected from a wide range of substances. However, in many cases, there is a problem with the solubility in the polymer binder, and from the viewpoint of durability, it is not only suitable for new applications other than electrophotographic photoreceptors, but also for a wide range of requirements for electrophotographic processes. At present, a photoconductive material that can sufficiently answer the question has not yet been obtained. The present invention not only excels in electrophotographic characteristics such as charging characteristics, charge holding power, sensitivity, residual potential, etc., but also has good coating characteristics and little deterioration due to repeated use, and various characteristics change with heat, temperature and light. An object of the present invention is to provide an organic photoconductive material which can exhibit stable performance without any disadvantages and which can be used as an electrophotographic photoreceptor and a sensor material, an EL element, an electrostatic recording element, etc., in which the disadvantages of the above-mentioned known technology are improved. It is assumed that.

[0004]

Accordingly, the present inventors have studied to improve the organic electrophotographic photoreceptor and obtained the following general formula [1]:
The present inventors have found that the hydrazone compound represented by the formula (1) has excellent photoconductivity. That is, the present invention
An object of the present invention is to provide an organic photoconductive material comprising a hydrazone compound represented by the following general formula [1]. General formula [1]

[0005]

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(Wherein A and B represent the same or different hydrogen atoms, alkyl groups, substituted / unsubstituted aromatic hydrocarbon ring groups or substituted / unsubstituted aromatic heterocyclic groups, and m is 0 or 1 , N represents 3, 4, 5, or 6, and R represents a hydrogen atom or a methyl group.)
Specific examples of the hydrazone compound useful in the present invention represented by the following are, for example, exemplified compounds (1) to (1) having the following structural formulas:
(32), but this does not limit the hydrazone compound of the present invention.

[0007]

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[0008]

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[0009]

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[0010]

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[0011]

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[0012]

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[0013]

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[0014]

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The above hydrazone compound can be synthesized by a known method. That is, an aldehyde represented by the following general formula [2] or [3] and an equimolar or slightly excessive amount of a hydrazine represented by the general formula [4] or a mineral acid salt thereof and methanol or ethanol are used. It can be synthesized by reacting in such a solvent. General formula [2] A-CHO ... [2] General formula [3]

[0016]

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General formula [4]

[0018]

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(Wherein A, B, R and n are the same as described above) In this reaction, a small amount of an organic acid such as acetic acid, an inorganic acid or an organic base such as triethylamine is optionally used as a condensing agent. be able to. The physical composition of the electrophotographic photoreceptor of the present invention may be in any of known forms. A carrier generation layer mainly containing the azo compound as a carrier generation substance and a carrier transportation layer mainly containing a carrier transportation substance may be stacked on a conductive support. A photosensitive layer dispersed in a transport material may be provided. Since these may be provided via an intermediate layer, the following patterns are possible. 1) Support / Carrier Generating Layer / Carrier Generating Layer 2) Support / Carrier Generating Layer / Carrier Generating Layer 3) Support / Carrier Generating Layer Containing Carrier Generating Material 4) Support / Intermediate Layer / Carrier Generating Layer / Carrier Transport layer 5) Support / intermediate layer / Carrier transport layer / Carrier generating layer 6) Support / Intermediate layer / Carrier transport layer containing carrier generating material Here, the intermediate layer is a barrier layer or an adhesive layer. It is also possible to provide a thin layer on the photoreceptor having the above structure for the purpose of protecting the surface. The carrier transporting substance includes a substance that transports electrons and a substance that transports holes, and both can be used for forming the photoreceptor of the present invention.

The electrophotographic photoreceptor of the present invention can be produced by an ordinary method according to a technique known in the production of a photoreceptor using an organic photoconductive substance. For example, the carrier generation layer forming the photosensitive layer having a two-layer structure is obtained by forming the azo compound into fine particles in an appropriate medium, adding a binder as necessary, and directly on the conductive support or via an intermediate layer. Or over the carrier transport layer already formed and dried. The fine particles in the medium have a diameter of 5μ or less,
It is necessary to disperse the dispersion preferably at 3 μm or less, optimally at 1 μm or less. There is no particular limitation on the use of a binder, but a film-forming polymer compound that is hydrophobic, has a high induction ratio, and is electrically insulating is preferable. Various thermoplastic or thermosetting synthetic resins can be suitably used. As will be readily appreciated, the medium advantageously has the ability to dissolve the binder. The binder can be used in an amount of 0.1 to 5 times the weight of the carrier-generating substance. The thickness of the carrier generation layer is in the range of 0.01 to 20 μm. Preferably it is 0.05-5 μm. The carrier transporting layer can be formed by dispersing or dissolving a carrier transporting substance in a suitable medium, coating and drying. It is preferable to use a separate binder unless the carrier transporting substance uses a substance which also functions as a binder itself, such as poly-N-vinylcarbazole or polyglycidylcarbazole. As the binder, those similar to the binder used for forming the carrier generation layer can be used. The amount of the binder used is suitably 0.2 to 5 times the weight of the carrier infusion substance. The thickness of the carrier transport layer is in the range of 1 to 100 μm, preferably 5 to 50 μm.
μ.

On the other hand, in order to form a dispersion-type carrier generation-carrier transport layer, a carrier transport substance is dissolved or dispersed in the above-mentioned dispersion for forming a carrier generation layer and applied onto a conductive support. good. The carrier transporting substance can be arbitrarily selected, but it is generally preferable to add a binder, except for the use of a substance which itself serves as a binder as described above. When an intermediate layer is provided between the conductive support and the above-described laminated or dispersed photosensitive layer, the intermediate layer may include one or a mixture of two or more of a carrier-generating substance, a carrier-transporting substance, a binder, and an additive. Further, a commonly used material can be used as long as the function as the intermediate layer is not impaired. The film thickness is 10 μm or less, preferably 1 μm or less. Other known techniques can be applied to the electrophotographic photosensitive member of the present invention. For example, the photosensitive layer may contain a sensitizer. Suitable sensitizers include Lewis acids and dye dyes that form a charge transfer complex with the organic photoconductive material. Also, the film formability of the photosensitive layer,
Additives such as a plasticizer, an ultraviolet absorber, an antioxidant, a lubricant, an adhesion promoter, and a dispersant may be added as needed to improve flexibility, mechanical strength, and the like. A carrier-generating substance and a carrier-transporting substance may be added as long as the characteristics of the electrophotographic photosensitive member are not impaired. In the present invention, an ordinary coating method can be used as a method for forming the carrier generation layer, the carrier transport layer, and the intermediate layer or the surface layer. The electrophotographic photoreceptor of the present invention is excellent in charging characteristics, sensitivity characteristics and image forming properties as is clear from the following specific examples, has good photosensitivity, and has sensitivity and charging characteristics even when used repeatedly. Small fluctuation in characteristics, low light fatigue, and high light resistance.

[0022]

The following are examples of the hydrazone compound of the present invention. Other hydrazone compounds represented by the general formula [1] can be synthesized according to the following synthesis examples. Synthesis Example In the case of Exemplified Compound (3) 1,1-bis (p-anisyl) -acrolein 13.4 parts by weight, 9-amino-1,2,3,4-tetrahydrocarbazole 10.4 parts by weight, glacial acetic acid 5 Parts by weight of methanol 3
The mixture is refluxed and stirred in 00 parts by weight for 3 hours. After cooling, the resulting crystals were separated by filtration, washed with methanol, and recrystallized from acetonitrile to give 15.9 parts by weight of 9- [3,3-bis (p-anisyl) -2-propenylideneamino]-. 1,2,3,4
-Tetrahydrocarbazole was obtained. The yield was 73%. Example 1 1 part by weight of chlordiane blue and 1 part by weight of a polyester resin [manufactured by Toyobo Co., Ltd., trade name "Vylon 200"] were put in a ball mill together with 50 parts by weight of tetrahydrofuran and sufficiently dispersed. The composition was applied on an aluminum plate and dried with hot air at 110 ° C. for 30 minutes to provide a carrier generating layer having a thickness of 0.3 μm. On top of this, 5 parts by weight of the exemplary compound (1) and a polycarbonate resin [Teijin Kasei
Co., Ltd., trade name "Panlite L-1250"], and a solution prepared by dissolving 5 parts by weight in 70 parts by weight of 1,2-dichloroethane is applied, dried with warm air at 80 ° C. for 60 minutes, and has a film thickness of 20 μm. A carrier transport layer was formed. The photoreceptor thus produced was left in an atmosphere of 25 ° C. and 55% RH (relative humidity), and after adjusting the humidity, an electrostatic paper recording device [manufactured by Kawaguchi Electric Works, Ltd.
Using the product name "SP-428"], the sample was corona-charged at a voltage of -5 KV by a static method and kept in a dark place for 10 seconds.
Exposure was performed so as to be 0 lux, and the electrophotographic characteristics were evaluated. The following results were obtained. Vo (initial voltage of charging) = 870 (−V) V _D10 (potential holding ratio in a dark place for 10 seconds) = 96 (%) E1 / 2 (half-exposure amount) = 2.9 (lux · s) VR (Residual potential) = 7 (−V) Examples 2 to 6 Photoconductors were prepared in the same manner as in Example 1 except that the following exemplary compounds were used instead of the exemplary compound (1) in Example 1. The characteristics were measured in the same manner.
It was as shown in the table.

[0023]

[Table 1]

Example 7 2 parts by weight of an azo compound represented by the following general formula [5] and a polyester resin [manufactured by Toyobo Co., Ltd .;
0 "] 1 part by weight was placed in a ball mill together with 100 parts by weight of tetrahydrofuran and sufficiently dispersed, and the dispersion was applied to a polyester film on which aluminum was deposited, and 11
Drying was performed with hot air at 0 ° C. for 30 minutes to form a carrier generating layer having a thickness of 0.5 μm. General formula [5]

[0025]

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Next, 10 parts by weight of the exemplified compound (2) and 10 parts by weight of a polycarbonate resin [trade name "Panlite L-1250" manufactured by Teijin Chemicals Ltd.] are dissolved in 100 parts by weight of 1,2-dichloroethane. 80 ° C
The carrier transport layer having a thickness of 20 μm was formed by drying with warm air for 60 minutes. When the characteristics of the photoreceptor thus manufactured were measured in the same manner as in Example 1, the following results were obtained. Vo = 870 (−V) V _D10 = 95 (%) E1 / 2 = 1.6 (lux · sec) VR = 4 (−V) Examples 8 to 13 Instead of the exemplified compound (2) in Example 7, A photoreceptor was prepared in the same manner except that the following exemplified compounds were used, and the characteristics were measured. The results were as shown in Table 2.

[0027]

[Table 2]

A mirror-finished aluminum drum was dip-coated on the carrier-generating material dispersion prepared in Example 7, and
The resultant was dried with hot air of 30 ° C. for 30 minutes to form a carrier generating layer having a thickness of 0.5 μm. The carrier transport material solution prepared in Example 10 was applied thereon by dip coating, and dried with warm air at 80 ° C. for 60 minutes to form a carrier transport layer having a thickness of 20 μm. This photoreceptor was mounted on a commercially available copying machine, and the surface potential was adjusted to -700 V by corona discharge. After image exposure, development, transfer, blade cleaning, and static elimination were performed. Image was obtained. Even when this copying test was repeated 10,000 times, no change in the image was observed.

[0029]

As described above, according to the present invention, by using a hydrazone compound having a specific composition as a carrier transporting material, various characteristics such as charging characteristics, charge holding power, sensitivity, residual potential, and image forming properties are excellent. In addition, an electrophotographic photoreceptor having no characteristic fluctuation even when used repeatedly for a long time can be obtained. Therefore, it is possible to provide a laminated or dispersed electrophotographic photosensitive member having high performance and high durability.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Osamu Suda, Inventor 804-26, Otani, Omiya City, Saitama (72) Inventor, Masaru Hasegawa 5-52-12, Yoyogi, Shibuya-ku, Tokyo (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 5/06 324-326 CA (STN)

Claims (3)

(57) [Claims] 1. An organic photoconductive material represented by the following general formula [1]. General formula [1] (Wherein A and B represent the same or different hydrogen atoms, alkyl groups, substituted / unsubstituted aromatic hydrocarbon ring groups or substituted / unsubstituted aromatic heterocyclic groups, m is 0 or 1, and n is 3, 4, 5 or 6, and R represents a hydrogen atom or a methyl group.) 2. An electrophotographic photosensitive member having a photosensitive layer,
An electrophotographic photosensitive member, wherein the photosensitive layer contains a hydrazone compound represented by the general formula [1]. 3. The electrophotographic photoreceptor according to claim 2, wherein the photosensitive layer contains a carrier generating substance and a carrier transporting substance, and the carrier transporting substance is a hydrazone compound represented by the general formula [1].