JPH02135359A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body having superior electrophotographic characteristics by incorporating a specified compd. as charge transfer material of a photosensitive layer. CONSTITUTION:A compd. expressed by the formula I is incorporated as charge transfer material of a photosensitive layer formed on an electroconductive base body. In the formula I, X is O, C(CN)2, or C(CO2R)2 (wherein R is an alkyl group); each R1 and R2 is an H atom, alkyl group, aryl group, alkoxycarbonyl group, aryloxycarbonyl group, nitro group, halogen atom, or cyano group; each (m) and (n) is zero-2. Thus, an electrophotographic sensitive body having superior electrophotographic characteristics is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electrophotographic photoreceptor for forming an electrostatic latent image.

Conventional technology Conventionally, electrophotographic photoreceptors using organic photoconductors have been studied in various ways because they have advantages such as non-pollution, high productivity, and low cost. Those using derivatives are also known (see, for example, Japanese Patent Application Laid-Open No. 54-30834).

By the way, among organic photoconductors, materials that absorb visible light and generate electric charge have poor charge retention ability, whereas materials that have good charge retention ability and excellent film forming properties generally cannot be used with visible light. The drawback is that it has almost no photoconductivity. In order to solve this problem, we developed a laminated photosensitive layer that has a layer structure in which the photosensitive layer is functionally separated into a charge-generating material that absorbs visible light and generates a charge, and a charge-transporting material that transports the charge. things are being done. Many charge generation materials and charge width transfer materials have been proposed. As hole transport materials, amine compounds, hydrazone compounds, pyrazoline compounds, oxazole compounds, oxadiazole compounds, stilbene compounds, carbazole compounds, etc. are known, and as electron transport materials, 2, 4.
Examples include 7-dolinitrofluorenone. Others, for example, Japanese Patent Publication No. 48-9988 and Canadian Patent No. 912
019@ The specification describes compounds containing poron.

Problems to be Solved by the Invention However, as for electrophotographic photoreceptors with a single layer structure using an organic photoconductor, a sufficiently practical sensitizing material is not yet known. In addition, in a function-separated type electrophotographic photoreceptor having a laminated structure, a positively charged type is preferable from the viewpoints of preventing ozone generation in the corotron, controlling toner charge during development, and the like. However, when used as a positively charged type, if the charge transport material has hole transport properties, it is necessary to provide a charge generation layer as an upper layer. This is insufficient to satisfy the mechanical properties of the body. In addition, it is necessary to devise measures on the copying machine side for use with negative charging.

Therefore, there is a desire to obtain a positively charged photoreceptor with a relatively thick charge transport layer as an upper layer, and for this purpose, it is necessary to use an electron transport material with electron transport properties in the charge transport layer. It is. However, none of the electron transporting materials proposed so far that are sufficiently effective are known.

The present invention has been made in view of the above-mentioned conventional problems.

Therefore, an object of the present invention is to provide an electrophotographic photoreceptor having excellent electrophotographic properties.

Another object of the present invention is to provide a laminated electrophotographic photoreceptor for positive charging that has excellent electrophotographic properties.

Means for Solving the Problems As a result of research, the present inventors have discovered an electrophotographic sensitizer that exhibits good electrophotographic properties when a compound represented by the following formula (I) is used as a sensitizer or charge transport material. The present invention was completed based on the discovery that the present invention can be obtained by the following methods.

The electrophotographic photoreceptor of the present invention is characterized in that it has a photosensitive layer on a conductive support, and the photosensitive layer contains a compound represented by the following I as a charge transporting material. shall be.

(wherein, X is 0.C(CN)2 or c<co2R)2
(R is an alkyl group), R1 and R2 each represent a hydrogen atom, an alkyl group, an aryl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a nitro group, a halogen atom, or a cyano group, and m and n each represent 0~2) The above-mentioned coin used in the present invention (
Examples of the compound represented by I) include the following.

Nos Now N0i Among these compounds, the compound in which X is C(CN)2 can be synthesized by treating a xanthone derivative with thionyl chloride and reacting it with malonitrile. In addition, a compound where X is C(Co2R)2 can be obtained by hydrolyzing a compound where X is C(CN)2,
It can be obtained by an esterification method.

(Synthesis example) Synthesis of exemplified compound (1) Xanthone 20 (J,
After adding 100 m of thionyl chloride, Q, and stirring under a nitrogen stream for 3 hours, thionyl chloride was distilled off under reduced pressure. Add 10q of malonitrile to the residue, and add 10q of malonitrile to the residue while stirring vigorously.
After heating to 100°C for an hour, it was cooled and the reaction mixture was dissolved in methylene chloride. The obtained methylene chloride solution was purified using a silica gel short column, and then methylene chloride was distilled off under reduced pressure. The residue was washed twice with a small amount of cold ethyl acetate, and then recrystallized from toluene to obtain Exemplified Compound (1) 15.
1 g (61% yield) was obtained as a yellow powder. Melting point: 2
52 to 255° C. In the electrophotographic photoreceptor of the present invention, examples of the conductive support include a metal pipe, a metal plate, a metal sheet, a metal foil, a conductive-treated polymer film, and A.
: A polymer film with a vapor-deposited layer of metal such as SnO2
A polymer film or paper coated with a metal oxide such as, a quaternary ammonium salt, etc. is used.

In the electrophotographic photoreceptor of the present invention, a photosensitive layer is provided on the conductive support, but the photosensitive layer may have a single layer structure, or may be functionally separated into a charge generation layer and a charge transport layer. It may also have a laminated structure.

When the photosensitive layer has a single-layer structure, for example, a photosensitive layer made of a known material such as polyvinylcarbazole contains the compound represented by (I) above as a sensitizing material, or a known material. For example, a binder resin layer containing a charge generating material may contain a compound represented by (I) above as an electron transporting material.

On the other hand, in the case where the photosensitive layer has a laminated structure, the charge generation layer may be obtained by depositing a charge generation material on a conductive support, or it may consist mainly of a charge generation material and a binder resin. It may be formed by applying a coating liquid as a component.

As the charge generating material and the binder resin, any known ones may be used.
You can use anything. For example, as the charge generating material, inorganic semiconductors such as tri-3e, organic semiconductors such as polyvinylcarbazole, organic pigments such as bisazo compounds, trisazo compounds, phthalocyanines, pyrylium compounds, and squareium compounds can be used.
Binder resins include polystyrene, silicone resin, polycarbonate resin, acrylic resin, methacrylic resin,
Polyester, vinyl polymers, celluloses, alkyd resins, etc. can be used.

The thickness of the charge generation layer is set to about 0.05 to 10 μm.

A charge transport layer is formed on the charge generation layer.

This charge transport layer is composed of the compound represented by -I> and a binder resin, and is mainly composed of the compound represented by -I>, the binder resin, and a suitable solvent. It is formed by applying a coating liquid as a component onto the charge generation layer using an applicator, bar coater, dip coater, or the like.

In this case, the mixing ratio of the compound represented by -I> and the binder resin is set to about 1:20 to 20:1.

Any known binder resin can be used for the charge transport layer. For example, styrene-butadiene copolymer, vinyltoluene-styrene copolymer, styrene-modified alkyd resin, silicone-modified alkyd resin, soybean oil-modified alkyd resin, vinyldene chloride-vinyl chloride copolymer, polyvinyl butyral, nitrated polystyrene, Polymethylstyrene, polyisobutylene, polyester, phenolic resin, ketone resin,
Examples include polyamide, polycarbonate, polythiocarbonate, polyvinyl haloarylate, vinyl acetate resin, polystyrene, polyvinyl acrylate, polysulfone, and polymethacrylate. Further, an electron donating substance may be added to the charge transport layer.

The thickness of the charge transport layer is set to about 2 to 100 μm.

In addition, in the electrophotographic photoreceptor of the present invention, a barrier layer may be provided on the conductive support. The barrier layer is effective in preventing unnecessary charge injection from the conductive support, and has the effect of improving image quality. Materials constituting the barrier layer include metal oxides such as aluminum oxide, acrylic resins, phenolic resins, polyester resins,
Examples include polyurethane.

Example Hereinafter, the present invention will be explained by examples.

Example 1 A charge generation layer (2.5) consisting of trigonal selenium/polyvinylcarbazole (trigonal selenium capacity %) was provided on a conductive substrate, and exemplified compound (1) 0
．． A solution of 5 g and 0.75 g of bisphenol A polycarbonate (Macrolon 5705) dissolved in 7 q of styrene chloride was applied with a wet gap of 5 mil,
It was dried at ℃ for 1 hour to prepare an electrophotographic photoreceptor. This electrophotographic photoreceptor was tested using an electrostatic copying paper tester (SP4).
28 (manufactured by Kawaguchi Electric Seisakusho ■) to +aoov and -800ν, exposed to 5 lux white light, and measured sensitivity 1 (dV/dt).

The results were as follows.

Charge potential +800V -800V Initial sensitivity
93 (V/5ec) Examples 2 to 4 In place of exemplified compound (1), exemplified compound (3), (9
) and (13) were used, an electrophotographic photoreceptor was prepared in the same manner as in Example 1, and the sensitivity was measured in the same manner. The results are shown in Table 1.

Comparative Example 1 An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that 2.4.7-dolinitrofluorenone (TNF) was used instead of Exemplified Compound (1), and the sensitivity was adjusted in the same manner. It was measured. The results are shown in Table 1.

Table 1 Example 5 On a conductive substrate, 0.59 g of Exemplified Compound (1) and 0.75 g of polyvinylcarbazole were added to 7 g of methylene chloride. ?
Apply a solution dissolved in , with a wet gap of 5 mils,
It was dried at 80° C. for 1 hour to prepare an electrophotographic photoreceptor.

These electrophotographic photoreceptors were tested using an electrostatic copying paper tester (SP42B, manufactured by Kawaguchi Electric Seisakusho (1)).
It was charged to 800 V and -800 V, exposed to 5 lux white light, and the sensitivity (dV/dT) was measured. The results were as follows.

Charge potential +800V -800V Initial sensitivity
195 184 (V/sec) Examples 6 to 8 Exemplary compound (3), (9
) and (13) were used, an electrophotographic photoreceptor was prepared in the same manner as in Example 5, and the sensitivity was measured in the same manner. The results are shown in Table 2.

Comparative Example 2 An electrophotographic photoreceptor was prepared in the same manner as in Example 13, except that 2.4.7-dolinitrofluorenone (DinNF) was used in place of Exemplified Compound (1), and sensitivity was determined in the same manner. was measured. The results are shown in Table 2.

The compound represented by the second formula exhibits better electron transport properties than TNF, which is conventionally known to be relatively excellent, and therefore, an electrophotographic photoreceptor using this compound exhibits excellent electrophotographic properties. . In particular, when used as a charge transport material in a charge transport layer of a laminated electrophotographic photoreceptor, a positively charged electrophotographic photoreceptor exhibiting excellent electrophotographic properties can be obtained.

Patent applicant Fuji Xerox Co., Ltd. Agent
Patent Attorney Tsuyoshi Seibu Effects of the Invention As is clear from the comparison of the above embodiments and comparative examples, the above-mentioned amendment used in the present invention (I) was submitted by the Japan Patent Office on July 19, 1999. Director Yoshi 1) Takeshi Moon1, Indication of the case 1987 Patent Application No. 2876162, Name of the invention Electrophotographic photoreceptor3, Relationship with the person making the amendment Patent applicant address 3 Akasaka, Minato-ku, Tokyo Chome 3-5 Name (
549) Fuji Xerox Co., Ltd. Representative: Yotabe Kobayashi 4, Agent address: 1-8-5-6, Kanda Nishiki-cho, Chiyoda-ku, Tokyo 101, Japan Contents of amendment (1) “Chloride” on page 11, line 11 of the specification Vinylden”
"Correct to vinylidene chloride J.

that's all “Detailed description of the invention” column in the specification

Claims (1)

[Claims] (1) An electrophotographic photoreceptor comprising a photosensitive layer provided on a conductive support, characterized in that the photosensitive layer contains a compound represented by the following general formula (I) as a charge transport material. Electrophotographic photoreceptor. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, X is O, C(CN)_2 or C(CO_2R)
)_2 (where R is an alkyl group), R_1 and R_2 are,
Each represents a hydrogen atom, an alkyl group, an aryl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a nitro group, a halogen atom, or a cyano group, and m and n are
each indicates 0 to 2)