JPH0561218A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To provide an electrophotographic sensitive body having high sensitivity and satisfactory durability. CONSTITUTION:This electrophotographic sensitive body has an electric charge generating material and an electric charge transferring material on the electric conductive substrate and the electric charge transferring material is a compd. represented by the formula (where X is S or Se, Y is optionally substd. alkyl, optionally substd. aryl or cyano, R is optionally substd. alkyl, optionally substd. aryl, cyano, nitro, halogen or H and n is 1, 2 or 3).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charge transport material used in an electrophotographic photoreceptor, and more specifically, the present invention is
The present invention relates to an electrophotographic photoreceptor containing an aromatic compound as a charge transport material.

[0002]

2. Description of the Related Art Conventionally, as a photosensitive layer of an electrophotographic photoreceptor,
Inorganic photoconductive substances such as selenium, selenium-tellurium alloy, and zinc oxide have been widely used, but in recent years, research on electrophotographic photoreceptors using organic photoconductive substances has progressed, and some of them have been put to practical use. ing. Here, most of the photoconductors that have been put to practical use are laminated electrophotographic photoconductors that include a photogenerating layer having a charge-generating layer and a charge-transporting layer that have different functions. The electrophotographic photoconductor is actively designed, which is improved in terms of sensitivity and photoconductor life, which are inferior to those of the human body, and is low cost, and takes advantage of the advantages of organic photoconductive materials such as safety and versatility. It became so.

This type of laminated electrophotographic photoreceptor is generally a charge generating layer made of a charge generating substance such as a pigment or a dye, and a charge transporting layer made of a charge transporting substance such as hydrazone or pyrazoline on a conductive support. Are sequentially formed. Due to the nature of the electron-donating charge transport material, they are of the hole transfer type and have sensitivity when negatively charged on the surface of the photoreceptor. However, with negative charging, the corona discharge used during charging is more unstable than with positive charging, and ozone is about 10 times as much as during positive charging.
There is a problem that nitrogen oxides and the like are generated, and physical deterioration such as adsorption on the surface of the photoconductor or chemical deterioration is easily caused, and further the environment is deteriorated. Still another problem is that the development of the negative charging photoreceptor requires a toner having a positive polarity, but the toner having a positive polarity is difficult to manufacture in view of the triboelectrification series in which the carrier particles of ferromagnetic material are contained. In the component high-resistance magnetic brush developing method, the negatively charged toner / developer is more stable, and the degree of freedom in selection and use conditions is large, and in this respect, the range of application to the positively charged type photoreceptor is wide and advantageous.

Therefore, it has been proposed to use a photoconductor using an organic photoconductive material with a positive charge. For example, when a charge transport layer is laminated on the charge generation layer to form a photoreceptor, the charge transport layer has a large electron transport ability, for example, 2,
Although 4,7-trinitro-9-fluorenone and the like are used, there is a problem that the substance has carcinogenicity and is extremely unsuitable for occupational health.

Further, as a positively charged photoreceptor, US Pat.
No. 615,414 discloses that thiapyrylium salt (charge generating substance) is contained so as to form a eutectic complex with polycarbonate (binder resin). However, this known photoconductor has a drawback that a memory phenomenon is large and a ghost is easily generated.

Therefore, the charge generation layer containing a charge generation substance that generates holes and electrons at the time of light irradiation is used as an upper layer (surface layer), and the charge transport layer containing a charge transport substance having a hole transport ability is used as a lower layer. It is considered that a photoreceptor having a laminated photosensitive layer can be used for positive charging. However, since the layer containing the charge generating substance is formed as the surface layer in the positive charging photoreceptor, at the time of light irradiation, short-wavelength light irradiation such as ultraviolet light irradiation,
Corona discharge, humidity, a charge generating substance vulnerable to external action such as mechanical friction will be present in the vicinity of the surface layer, electrophotographic performance is deteriorated during storage of the photoconductor and during image formation,
The image quality will deteriorate.

In the conventional negative charging photoreceptor having the charge transport layer as the surface layer, the influence of the various external actions is extremely small, and rather the charge transport layer has a function of protecting the lower charge generating layer. is doing.

Therefore, for example, a thin protective layer made of an insulating and transparent resin may be provided to protect the layer containing the charge generating substance from an external action. However, the charge generated during light irradiation is the protective layer. The light irradiation effect is lost due to blocking, and the sensitivity is lowered when the thickness of the protective layer serving as the surface layer is large.

Although various attempts have been made to obtain a photoconductor for positive charging as described above, all of them have many problems to be solved in terms of photosensitivity, memory phenomenon, occupational health and the like.

[0010]

DISCLOSURE OF THE INVENTION The present invention is intended to provide an electrophotographic photoreceptor containing a charge generating substance and a charge transporting substance on a conductive support and having high sensitivity and durability.

[0011]

Means for Solving the Problems The inventors of the present invention have conducted extensive research to solve the above-mentioned problems and, as a result, found a specific group of compounds and completed the present invention.

That is, the present invention is an electrophotographic photoreceptor containing an aromatic compound represented by the following general formula I as a charge transport material.

[0013]

[Chemical 2]

Where X is a sulfur or selenium atom, Y is a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a cyano group, and R is a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group. Group, cyano group,
Nitro group, halogen atom, or hydrogen atom, n is 1, 2
Or represents 3.

In the above general formula I of the present invention, Y is, for example, methyl group, ethyl group, n-butyl group, t-butyl group,
Examples thereof include an alkyl group such as a benzyl group, a phenyl group, a naphthyl group, and an aryl group. Further, R is a methyl group, an ethyl group, an n-butyl group, a t-butyl group, an alkyl group such as a benzyl group, a phenyl group, an aryl group such as a naphthyl group, a cyano group, a nitro group, a hydrogen atom or a fluorine atom, chlorine. An atom, a halogen atom such as a bromine atom and an iodine atom can be mentioned.

Specific examples of the aromatic compound of the general formula I of the present invention are shown in Table 1, but not limited thereto.

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

[Table 3]

[0020]

[Table 4]

[0021]

[Table 5]

These compounds of general formula I are generally prepared as follows. First, the compound of the following (Chemical Formula 3) in which the substituent Y of the compound represented by the general formula I is a cyano group is

[0023]

[Chemical 3]

(Where X, R and m are the same as those in formula I) can be obtained by diazotizing an amino compound represented by the following (formula 4).

[0025]

[Chemical 4]

(Wherein R and n are the same as those in formula I) are produced by reacting a diazonium salt of the following (Chemical Formula 5) with potassium thiocyanate or potassium selenocyanate.

[0027]

[Chemical 5]

(Wherein R and n are the same as those in the general formula I. Z represents an anionic functional group) The diazotization of the amino compound represented by the formula (4) is carried out by converting the amino compound into an inorganic acid such as hydrochloric acid or sulfuric acid. After dispersing in it, -10 to 20 ° C
The reaction is completed by adding sodium nitrite at a temperature of about 2 hours. By this reaction, the diazonium salt of (Chemical Formula 5) can be obtained. Furthermore, the compound of Chemical formula 3 can be produced by adding an aqueous solution of potassium thiocyanate or potassium selenocyanate to this diazotization reaction liquid at the same temperature.

Next, a compound represented by the general formula I in which the substituent Y is a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group is obtained by reducing the compound of the formula (3) It is produced by reacting the anionic species of Chemical formula 6) with an alkylating agent or an arylating agent.

[0030]

[Chemical 6]

(However, X, R, and n are the same as in the general formula.) As the reducing agent used in the reduction reaction of the compound of Chemical formula 3,
Sodium hydride, potassium hydride, calcium hydride, lithium aluminum hydride, potassium borohydride, calcium hydride, lithium aluminum hydride,
Although a metal halide such as sodium borohydride or an alkaline reagent such as sodium hydroxide or potassium hydroxide can be used, sodium borohydride, which can be easily post-treated for the reduction reaction, can be favorably used. In this reaction, an oxidation reaction occurs due to oxygen in the air or dissolved oxygen in the reaction solvent, so it is preferable to carry out the reaction while blowing an inert gas. This reduction reaction is completed in 5 minutes to 1 hour.
The compound of the general formula I can be produced by reacting this reducing reaction with an alkylating agent or an arylating agent. As a reaction reagent used in this reaction, a halogenated alkylating agent such as methyl iodide, ethyl iodide, ethyl bromide, propyl bromide, butyl chloride or an arylating agent such as iodobenzene, mesityl bromide, naphthyl bromide can be used. .. The reaction temperature may be room temperature, but may be heated when the reaction is slow. Examples of the reaction solvent include methanol, ethanol, propanol, tetrahydrofuran, dioxane, diethyl ether and the like. The reaction is completed in 1 to 5 hours. After completion of the reaction, water is added to the reaction mixture, and extraction is performed with a reaction solvent or a solvent such as chloroform, 1,2-dichloroethane, dichloromethane, benzene, toluene. The extract is dried using a desiccant such as anhydrous magnesium sulfate, anhydrous sodium sulfate, and calcium chloride to remove residual water, and then the solvent is distilled off to obtain a crude product, which is then subjected to an appropriate method such as recrystallization or a silica gel column. The desired compound of general formula I can be obtained by purification by chromatography or the like.

In the compound of (Chemical Formula 3), a compound having a nitro group or a cyano group as R and n of 2 or 3 can be prepared by

[0033]

[Chemical 7]

(However, R and n are the same as those in the general formula I. A is a chlorine atom or a bromine atom.) Potassium thiocyanate or potassium selenocyanate can also be directly applied. Examples of the solvent used in this reaction include methanol, ethanol, propanol, tetrahydrofuran, dioxane, diethyl ether, benzene, toluene, acetone, methyl ethyl ketone, and the like.

Synthesis Example 1 (Production of Compound No. 1) 10.00 g (0.0) of 2,4-dinitrochlorobenzene
49 mol) was dissolved in 100 ml of acetone, and 5.02 g of potassium thiocyanate (0.
050 mol) is added. After adding all, acetone is heated to reflux. The reaction is completed in 6 hours. Thereafter, the precipitated KCl is filtered off and acetone is distilled off. 50 ml of crude product and 50 ml of 1,2-dichloroethane
The crystal obtained by recrystallization from the mixed solvent of was heated and dried under reduced pressure to obtain 9.57 g (yield 87%) of 2,4-dinitrobenzene thiocyanate of compound No. 1 as a pale yellow powder. m. p. 139 ° C Synthesis Example 2 (Production of Compound No. 2) 10.00 g (0.02) of 2,4-dinitrochlorobenzene
49 mol) was dissolved in 100 ml of acetone, and 7.20 g of potassium selenocyanate was added thereto at room temperature.
(0.050 mol) is added. After adding all, acetone is heated to reflux. The reaction is completed in 4 hours. After that, the precipitated inorganic salt of KCl is filtered off, and acetone is distilled off.
The crude product was recrystallized from 100 ml of ethanol, and the obtained crystal was dried by heating under reduced pressure to obtain 2,4-dinitrobenzene selenocyanate of compound No. 2 as a yellow powder.
1.25 g (yield 84%) was obtained. m. p. 165 ° C. Synthesis Example 3 (Production of Compound No. 3) 5.22 g (0.038 mol) of 4-nitroaniline was added to diluted hydrochloric acid composed of 25 ml of concentrated hydrochloric acid and 25 ml of water,
Stir at 50 ° C. After cooling to -5 ° C, a solution of 2.80 g (0.040 mol) of sodium nitrite dissolved in 50 ml of water was slowly added dropwise at -5 ° C to 0 ° C. Then, the mixture was stirred at the same temperature for 1 hour.

While maintaining the temperature at 0 ° C. or lower, sodium acetate aqueous solution was added to adjust the pH to 6, and then 6.0.
A solution prepared by dissolving 0 g (0.041 mol) of potassium selenocyanate in 30 mol of water was added dropwise. After completion of the dropping, the reaction temperature was heated to 60 ° C. and stirring was continued for 1 hour to complete the reaction. After cooling to room temperature, the reaction mixture is extracted with dichloromethane and dried over anhydrous magnesium sulfate. After distilling off dichloromethane, the crude product was recrystallized with 50 ml of ethanol, and the obtained crystal was collected by filtration and dried to obtain 5.18 g of 4-nitrobenzene selenocyanate of Compound No. 3 as a pale yellow powder (yield 60). %)Obtained. m. p. 121 ° C. Synthesis Example 4 (Production of Compound No. 4) 5.47 g (0.032 mol) of 2-bromoaniline was added to diluted hydrochloric acid consisting of 25 ml of concentrated hydrochloric acid and 25 ml of water,
Stir at 50 ° C. After cooling to -5 ° C, a solution of 2.57 g (0.037 mol) of sodium nitrite dissolved in 25 ml of water was slowly added dropwise at -5 ° C to 0 ° C. Then, the mixture was stirred at the same temperature for 1 hour.

While maintaining the temperature at 0 ° C., the pH was adjusted to 6 by adding an aqueous solution of sodium acetate, and then 5.10 g
(0.035 mol) potassium selenocyanate in water 3
A solution dissolved in 0 ml was added dropwise.

After completion of the dropping, the reaction temperature is heated to 60 ° C. to
Stirring was continued to complete the reaction. After cooling to room temperature, the reaction mixture is extracted with dichloromethane and dried over anhydrous magnesium sulfate. After distilling off with dichloromethane, vacuum distillation was carried out to obtain 4.50 g (yield 54%) of 2-bromobenzeneselenocyanate of Compound No. 4 as a red oily substance. b. p. 150 ° C. (4 mmHg) Synthesis Example 5 (Production of Compound No. 5) Nitrogen gas was blown into a solution prepared by dissolving 8.50 g (0.037 mol) of 4-nitrobenzene selenocyanate shown in Synthesis Example 3 in 20 ml of tetrahydrofuran at room temperature. However, 2.80 g (0.080) of sodium borohydride
(mol) was added dropwise to a solution suspended in 50 ml of tetrahydrofuran.

Then, the mixture was stirred at the same temperature for 1 hour. Then, at room temperature, 5.10 g (0.037 mo) of n-butyl bromide
A solution prepared by dissolving l) in 10 ml of tetrahydrofuran was added dropwise. After the dropping is completed, the mixture is heated to reflux and stirred for 3 hours,
The reaction was completed. After cooling to room temperature, the insoluble matter was filtered off, and the filtrate was extracted by adding 200 ml of dichloromethane. The extract is dried over anhydrous magnesium sulfate. After distilling off dichloromethane, the crude product was purified by a silica gel column chromatograph (developing solvent: toluene) and further purified to 70 m.
It was recrystallized from 1 l of ethanol, and the obtained crystals were collected by filtration and dried to obtain 4.25 g of n-butyl-4-nitrophenyl selenide of compound No. I-5 as a pale yellow powder (yield 51
%)Obtained. m. p. Table 2 shows the melting point or boiling point of the compound obtained as above at 136 ° C and the elemental analysis result.

[0040]

[Table 6]

Next, the structure of the photoconductor of the present invention will be described with reference to the drawings. As the photoconductor, for example, as shown in FIG. 1, a layer containing a charge generating substance and optionally a binder resin on a support 1 (a conductive support or a sheet on which a conductive layer is provided) (charge generating layer). 2) as a lower layer, and a photoreceptor layer 4 having a laminated structure in which a layer (charge transporting layer) 3 containing a charge transporting substance and optionally a binder resin as an upper layer is provided, and as shown in FIG. Protective layer 5 on photoreceptor layer 4
And the one in which a single-layer photosensitive layer 6 containing a charge-generating substance, a charge-transporting substance and, if necessary, a binder resin is provided on a support as shown in FIG. A protective layer may be provided on the photoreceptor layer 6 having the single-layer structure shown in FIG. 3, and an intermediate layer may be provided between the support and the photoreceptor layer.

As the charge generating substance used in the present invention,
If it absorbs visible light and generates free charge,
Both inorganic and organic substances can be used. For example, amorphous selenium, trigonal selenium, selenium-
Inorganic substances such as arsenic alloys, selenium-tellurium alloys, cadmium sulfide, cadmium selenide, cadmium sulfide selenide, mercury sulfide, lead oxide, lead sulfide, and amorphous silicon, or bisazo dyes, polyazo dyes, triarylmethane dyes , Thiazine dye, oxazine dye, xanthene dye, cyanine dye, styryl dye, pyrylium dye, quinacridone dye, indigo dye,
Examples thereof include perylene dyes, polycyclic quinone dyes, bisbenzimidazole dyes, indanthrone dyes, squarylium dyes, anthraquinone dyes, and phthalocyanine dyes.

Examples of the binder resin usable in the photosensitive layer in the present invention include polyethylene, polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, epoxy resin, polyurethane resin, phenol resin, polyester resin and alkyd. Resin, polycarbonate resin, silicone resin, addition polymerization type resin such as melamine resin, polyaddition type resin, polycondensation type resin,
And a copolymer resin containing two or more of the repeating units of these resins, for example, a vinyl chloride-vinyl acetate copolymer,
In addition to insulating resins such as vinyl chloride-vinyl acetate-maleic anhydride copolymer resins, polymer organic semiconductors such as poly-N-vinylcarbazole can be mentioned.

As the conductive support for supporting the photosensitive layer, a metal plate such as aluminum or nickel, a metal drum or a metal foil, a plastic film deposited with aluminum, tin oxide, indium oxide or the like, or a conductive substance is used. A coated paper, a film such as plastic, or a drum can be used.

When the photoreceptor according to the present invention is formed with a laminated structure of a charge generating layer and a charge transporting layer, that is, in the case of FIGS. 1 and 2 described above, the charge transporting material of the present invention is used in a suitable solvent. It is provided by a method of coating alone or dissolved or dispersed with an appropriate binder resin and drying. Examples of the solvent used for the charge transport layer include N, N-dimethylformamide, toluene, xylene,
Monochlorobenzene, 1,2-dichloroethane, dichloromethane, 1,1,1-trichloroethane, 1,1,2
-Trichloroethylene, tetrahydrofuran, methyl ethyl ketone, cyclohexanone, ethyl acetate, butyl acetate and the like can be mentioned. In this charge transport layer, the proportion of the charge transport material contained in the binder resin is 20 to 200 parts by weight of the charge transport material with respect to 100 parts by weight of the binder resin.

At this time, the thickness of the charge transport layer is preferably 5 to 50 μm, particularly preferably 5 to 30 μm.

The charge-generating layer is formed by vacuum-depositing the charge-generating substance on a conductive support, or by coating a suitable solvent alone or dissolved or dispersed with a suitable binder resin and drying it to form a charge-transporting layer. It can be similarly formed.

When the charge generating layer is formed by dispersing the above charge generating substance, it is preferable that the charge generating substance is a granular material having an average particle diameter of 2 μm or less, preferably 1 μm or less. That is, if the particle size is too large, the dispersion in the layer becomes poor, and the particles partially project on the surface and the surface smoothness deteriorates. Toner filming phenomenon tends to occur due to particles being attached. However, if the above particle size is too small, it tends to agglomerate, the resistance of the layer increases, the crystal defects increase and the sensitivity and repeatability deteriorate, or there is a limit on miniaturization, so the average particle The lower limit of the diameter is preferably 0.01 μm.

The charge generation layer can be provided by the following method. That is, the charge generating substance is made into fine particles in a dispersion medium by a ball mill, a homomixer, etc.,
This is a method of applying a binder resin and mixing and dispersing to obtain a dispersion liquid. In this method, if the particles are dispersed under the action of ultrasonic waves, uniform dispersion is possible. In the charge generation layer, the ratio of the charge generation substance contained in the binder resin is 20 to 200 with respect to 100 parts by weight of the binder resin.
It is considered to be part by weight.

The thickness of the charge generation layer formed as described above is preferably 0.1 to 10 μm, particularly preferably 0.5 to 5 μm.

Next, when the photoconductor of the present invention is formed in a single layer structure, that is, in the case of FIG. 3, the ratio of the charge generating substance and the charge transporting substance contained in the binder resin is 100 parts by weight of the binder resin. The charge generation material is 20 to 200 parts by weight, and the charge transport material is 20 to 200 parts by weight. The film thickness of the photoreceptor having this single-layer structure is 7 to 50 μm, more preferably 10 to 30 μm.

The intermediate layer functions as an adhesive layer or a barrier layer, and in addition to the above binder resin, for example, polyvinyl alcohol, ethyl cellulose,
Resins such as carboxymethyl cellulose, chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, casein, N-alkoxymethyl nylon as they are, or those in which tin oxide or indium oxide is dispersed, A vapor deposition film of aluminum oxide, zinc oxide, silicon oxide, or the like is used. The thickness of the intermediate layer is preferably 1 μm or less.

As the material used for the protective layer, it is suitable to use the above-mentioned resin as it is or to disperse a low resistance substance such as tin oxide or indium oxide. An organic plasma-polymerized film can also be used, and the organic plasma-polymerized film may optionally contain oxygen, nitrogen, halogen, and Group III or Group V atoms in the periodic table.

[0054]

EXAMPLES The present invention will be described in more detail below with reference to examples. In the examples, "parts" means "parts by weight" unless otherwise specified.

Example 1 5 parts of a bisazo dye represented by the following chemical formula (A), 2.5 parts of butyral resin (Denka butyral resin # 3000-2; manufactured by Denki Kagaku Kogyo) and tetrahydrofuran 92.
Disperse 5 parts in a ball mill for 12 hours, then add tetrahydrofuran to a dispersion concentration of 2% by weight,
The coating liquid was prepared by redispersion. The prepared dispersion liquid was cast and coated on a 100 μm-thick polyester film on which aluminum was vapor-deposited by a doctor blade to form a charge generation layer having a thickness of 1.0 μm after drying.

[0056]

[Chemical 8]

On the charge generation layer thus obtained,
6 parts of the exemplified compound (Compound No. 1) and 10 parts of a polycarbonate resin (Panlite K-1300; manufactured by Teijin Kasei) Methylphenylsilicone (KF50 100CPS;
(Shin-Etsu Chemical Co., Ltd.) 0.002 parts of a coating solution having a formulation of 0.004 parts and tetrahydrofuran 94 parts was prepared and cast-cast with a docker blade to form a charge-transporting layer having a film thickness after drying of 20.0 μm. A laminated electrophotographic photosensitive member (photosensitive member No. 1) composed of electrodes / charge generating layer / charge transporting layer was prepared.

Examples 2 to 5 Instead of the exemplified compound (Compound No. 1) of Example 1, compound 2, compound No. 3, compound No. 4 in the exemplified compound,
In the same manner as in Example 1 except that the compound No. 5 was used, the photoconductor No. 2, the photoconductor No. 3, the photoconductor 4, and the photoconductor No.
5 was produced. Example 6 Instead of 5 parts of the bisazo dye represented by the chemical formula (A) above, a trisazo dye 6 represented by the following chemical formula (B)
A charge generation layer was produced in the same manner as in Example 1 except that the parts were used.

[0059]

[Chemical 9]

On the charge generation layer thus obtained,
A coating liquid consisting of 6 parts of the exemplified compound (compound No. 1), 10 parts of a polycarbonate resin (Panlite K-1300; manufactured by Teijin Chemicals), 0.002 part of methylphenylsilicone (KF 100CPS; manufactured by Shin-Etsu Chemical), and 94 parts of tetrahydrofuran. And a charge transport layer having a film thickness after drying of 20 μm is formed in the same manner as in Example 1, and a laminated electrophotographic photoreceptor (photosensitive layer) composed of an aluminum electrode / charge generation layer / charge transport layer is formed. Body No. 6) was produced.

Examples 7 to 10 Example 6 Instead of the exemplified compound (Compound No. 1), Compound No. 2, Compound No. 3 and Compound No. 3 in the exemplified compound were used.
4. Photoconductor No. 7, photoconductor No. 8, photoconductor No. 9 and photoconductor No. 10 were prepared in the same manner as in Example 6 except that Compound No. 5 was used.

Example 11 5 parts of titanyl phthalocyanine (abbreviated as TiPc),
5 parts of polyvinyl butyral resin (S-Rex BLS; Sekisui Chemical Co., Ltd.) and 90 parts of tetrahydrofuran were dispersed in a ball mill for 12 hours, and then tetrahydrofuran was added to a dispersion liquid concentration of 2% by weight and redispersed to obtain a coating liquid. Was prepared. The coating solution thus prepared was cast and coated with a doctor blade onto a polyester film having a thickness of about 1000Å and having a thickness of 100 μm, and a charge generation layer having a thickness of 0.5 μm after drying was formed. ..

On the charge generation layer thus obtained,
6 parts of the exemplified compound (Compound No. 1) and a polycarbonate resin (Panlite K-1300; manufactured by Teijin Kasei) 10
Parts, and a coating solution having a formulation of 94 parts of tetrahydrofuran, prepared by flow casting with a doctor blade to form a charge transport layer having a thickness of 20.0 μm after drying, and an aluminum electrode / charge generation layer / charge transport layer. A laminated electrophotographic photosensitive member formed of layers was produced. Examples 12 to 15 Examples 12 to 15 were carried out except that Compound No. 2, Compound No. 3, Compound No. 4 and Compound No. 5 in the exemplified compound were used instead of Example 11 (exemplified compound No. 1). Photoconductor No. 12, photoconductor No. 13, photoconductor No. 14, in the same manner as in Example 11,
A photoconductor No. 15 was prepared.

With respect to the electrophotographic photosensitive member obtained as described above, an electrostatic copying paper test apparatus (Kawaguchi Denki Seisakusho: S
The characteristics were evaluated as follows using P-428).

After applying a corona charge of +6 KV and positively charging it, leave it in the dark for 20 seconds, measure the surface potential Vo at that time, and then use a tungsten lamp to light the surface so that the illuminance on the surface becomes 40 lux. The amount of exposure required to illuminate Vo at that time was halved by E1 / 2 (lux.se
c) and the surface potential V ₃₀ 30 seconds after the exposure were measured.
The results are shown in Table 3.

[0066]

[Table 7]

[0067]

As described above, the aromatic compound used as the charge transport material in the present invention can be synthesized relatively easily and has excellent solubility or dispersibility in the binder resin. Further, it has an excellent ability to receive the charge generated from the charge generating substance and transport it.

Therefore, the electrophotographic photoreceptor containing these compounds has a high dark decay rate and a high sensitivity.

[Brief description of drawings]

[Figure 1]

[Fig. 2]

FIG. 3 is a schematic cross-sectional view showing an example of the layer structure of the electrophotographic photoreceptor of the present invention.

4 is an infrared absorption spectrum of the compound No. 1 used in Example 1, FIG.

[Explanation of symbols]

 1 Support 2 Charge Generation Layer 3 Charge Transport Layer 4 Photoreceptor Layer (Layered Structure) 5 Protective Layer 6 Photoreceptor Layer (Single Layered Structure)

Front page continuation (72) Inventor Tetsuro Suzuki 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Masao Yoshikawa 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Akio Kojima 1-3-6 Nakamagome, Ota-ku, Tokyo Within Ricoh Co., Ltd.

Claims (2)

[Claims] 1. An electrophotographic photosensitive member containing a charge generating substance and a charge transporting substance on a conductive support, wherein the electrophotographic photosensitive member contains an aromatic compound as the charge transporting substance. 2. The electrophotographic photoreceptor according to claim 1, wherein the aromatic compound is represented by the following general formula I. [Chemical 1] Where X is a sulfur or selenium atom, Y is a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a cyano group, R is a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, cyano A group, a nitro group, a halogen atom, or a hydrogen atom, n represents 1, 2 or 3.