JPH07253682A - Electrophotographic photoreceptor using perylene pigment - Google Patents

Abstract

PURPOSE:To provide an electrophotographic photoreceptor high in sensitivity, good in electrophotographic characteristic and using a highly dispersible perylene pigment in a binder resin. CONSTITUTION:This electrophotographic photoreceptor is formed by providing at least one kind of perylene pigment shown by formula I on a conductive substrate. In formula I, R is expressed by formula II, X is alkyl, alkoxyl, halogen atom or nitro group, Y is -S- or -NH-, and (n) is 0, 1 or 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor containing a specific perylene pigment.

[0002]

2. Description of the Related Art Conventionally, various inorganic and organic photoconductive materials have been known as photoconductive materials in electrophotographic photoreceptors. When the organic photoconductive substance is used for an electrophotographic photoreceptor, it has advantages such as transparency of the film, good film forming property, flexibility, and cost reduction. In order to improve the sensitivity and durability of the photoconductor when using an organic photoconductive material, a laminated electrophotographic photoconductor in which a charge generation layer and a charge transport layer are functionally separated has been proposed. In recent years, Ph.D. has also been applied to charge generation materials used in laminated electrophotographic photoconductors.
otogr. Sci., 21, (2), 73 (1977), bisazo pigments, Rich Tech. Rep., 8, 14 (1982), trisazo pigments, J. Imag. Sci. .31, 31 (1987), Phthalocyanine pigments, Appl. Photogr. Sc
Various materials such as a perylene pigment as shown in i., 4, 118 (1978) have been proposed.

Regarding the perylene pigment, Japanese Patent Publication No. 61-8
Imidazole type compounds disclosed in Japanese Patent No. 423,
Bisalkylimide dip compounds as disclosed in JP-A-53-98825, JP-B-1-15865, JP-A-61-153658, and JP-A-63-
Bisarylalkylimide type compounds as disclosed in JP-A-266457 and JP-A-5-232726 have been proposed. Further, JP-B-61-2423 discloses that having a pyridine or pyrazine ring, and JP-A-1-159662 discloses that having a thiophene ring. Also, USP 4,714,66
No. 6, USP 5,019,473 discloses asymmetric perylene pigments. These perylene pigments form a vapor deposition film by vacuum vapor deposition as disclosed in USP 4,587,189, or a resin dispersion system as disclosed in USP 5,019,473. However, it is difficult to obtain a high quality image because the apparatus for vacuum evaporation is expensive and it is difficult to form a uniform evaporated film. Further, there are disadvantages that productivity is low and cost is high. on the other hand,
When used in a resin dispersion system, the productivity and cost can be improved, but since the binder resin is used, the photosensitivity is significantly inferior to the vapor deposition film, and if the pigment ratio is increased to increase the sensitivity, the sensitivity is improved. Although higher, the stability of the coating solution becomes lower and the pot life becomes shorter.

[0004]

As described above, the perylene pigments that have been proposed so far do not yet have sufficient characteristics, have sufficiently high photosensitivity, and are dispersed in a coating dispersion. Further improvement was desired in order to form a resin-dispersed charge generation layer having sufficiently good properties. The present invention has been made to solve the above-mentioned problems of the prior art. That is, an object of the present invention is to provide an electrophotographic photosensitive member using a perylene pigment that exhibits high sensitivity and good electrophotographic characteristics and is excellent in dispersibility in a binder resin.

[0005]

As a result of intensive studies, the present inventors have found that a perylene pigment having a specific heterocyclic group has excellent dispersion stability in a coating solution and high photosensitivity. It has been found that by using this pigment as a charge generating material, the above-mentioned object of the present invention can be achieved,
The present invention has been completed. The electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor having a photosensitive layer formed on a support, and the photosensitive layer contains at least one or more perylene pigment represented by the following general formula (1). It is characterized by

[Chemical 3] (In the formula, R is

[Chemical 4] X represents an alkyl group, an alkoxy group, a halogen atom or a nitro group, Y represents -S- or -NH-, and n means 0, 1 or 2. )

The present invention will be described in detail below. In the present invention, any conductive support can be used as long as it is used in an electrophotographic photoreceptor. Further, if necessary, the surface of the conductive support is
Various types of processing can be performed within a range that does not affect the image quality. For example, surface anodizing treatment, surface roughening treatment by liquid honing, chemical treatment, coloring treatment and the like can be performed. A photosensitive layer in which at least a charge generation layer and a charge transport layer are laminated is provided on the conductive support, but any order of lamination may be on the conductive support side. The charge generation layer in the present invention is composed of the perylene pigment represented by the general formula (1) and a suitable binder resin.

Specific examples of the perylene pigment represented by the above general formula (1) of the present invention include those in which the group R is as follows.

[Table 1]

The above perylene pigment of the present invention is 3,4
It can be synthesized by reacting 9,10-perylenetetracarboxylic dianhydride and the corresponding amino compound with heating in the absence of a solvent or in a suitable solvent such as quinoline or chloronaphthalene. A catalyst such as zinc acetate may be added during these reactions. The obtained perylene pigment was mechanically mixed with a pulverizing device such as a vibration mill, an automatic mortar, a sand mill, an attritor, and a ball mill to give a grain size of 0.1.
The fine particles obtained by pulverizing the fine particles to have a particle size of about 02 to 0.2 μm may be used as the charge generating material. A water-soluble salt such as sodium chloride or sodium sulfate may be used as a grinding aid during grinding, and when a salt is used, it is thoroughly washed with water after grinding. The salt may be used in an amount of 0.5 to 20 times, preferably 1 to 10 times the weight of the pigment. Before crushing J. Mater. Sc
It is preferable to carry out sublimation purification as shown in i., 17, 2781 (1982). Further, in order to wash away impurities and adjust to a preferable crystal form and particle size, solvent treatment may be performed after pulverization with a vibration mill, automatic mortar, sand mill, attritor, ball mill or the like.

In the electrophotographic photoreceptor of the present invention, other known charge generating materials may be used in combination with the perylene pigment of the present invention as a charge generating material. On the other hand, as the binder resin,
Any known material can be used. For example, polycarbonate, polystyrene, polyester,
Methacrylic acid ester polymer, polyvinyl butyral,
Examples thereof include polyacetal, vinyl acetate polymer, vinyl chloride-vinyl acetate copolymer, cellulose ester, cellulose ether, polybutadiene, polyurethane and epoxy resin. The compounding ratio (weight) of the charge generating material and the binder resin is 40: 1 to 1: 4, preferably 20: 1 to 1: 1.
It is 2. When the ratio of the charge generating material is too high, the stability of the coating solution is lowered, and when it is too low, the sensitivity is lowered, so that the above range is preferable.

As the solvent used for dispersion, water is methanol, ethanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, n-butyl acetate, dioxane. Examples include organic solvents such as tetrahydrofuran, methylene chloride, chloroform, benzene, toluene, xylene, chlorobenzene, dimethylformamide, dimethylacetamide, and mixed solvents thereof. As a dispersing means, a sand mill, a colloid mill, an attritor, a ball mill, a dyno mill, a co-ball mill, a roll mill or the like can be used. As a coating method, a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, a curtain coating method, or the like can be used.
The film thickness of the charge generation layer is 0.01 to 5 μm, preferably about 0.03 to 2 μm.

The charge transport layer is composed of a charge transport material and a film forming resin which is a binder resin. As the charge transport material, any known material can be used.
Examples of the film-forming resin include polycarbonate, polyarylate, polystyrene, polyester, styrene-
Examples thereof include acrylonitrile copolymer, polysulfone, polymethacrylic acid ester, styrene-methacrylic acid ester copolymer, and polyolefin. Among these, polycarbonate is preferable in terms of durability. The compounding ratio (weight) of the charge transport material and the film-forming resin is 5: 1 to
It is 1: 5, preferably 3: 1 to 1: 3. If the ratio of the charge transport material is too high, the mechanical strength of the charge transport layer will decrease, and if it is too low, the sensitivity will decrease, so the above range is preferred. Further, when the charge transport material itself has a film forming property, the above film forming resin can be omitted. The charge transport layer is formed by dissolving the above charge transport material and the film-forming resin in a suitable solvent and applying the solution, and the film thickness is 5 to 50 μm, preferably 10 to 10.
It is preferable to form it in the range of 40 μm. As a coating method for these photosensitive layers, any of the above-mentioned methods can be used.

Further, the electrophotographic photosensitive member of the present invention may be provided with an undercoat layer between the photosensitive layer and the conductive support, if necessary. The undercoat layer is effective in preventing unnecessary injection of charges from the conductive support, and has the function of increasing the chargeability of the photoconductor. Further, it also has the function of improving the adhesiveness between the photosensitive layer and the conductive support. The material constituting the undercoat layer, polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl pyridine, cellulose ethers, cellulose esters, polyamide, polyurethane, casein, gelatin, polyglutamic acid, starch, starch acetate, amino starch, polyacrylic acid, Polyacrylamide and the like can be used. Instead of the resin, a zirconium chelate compound, an organic zirconium compound such as zirconium alkoxide, and a silane coupling agent can be used. Typical examples of the organic zirconium compound in this case include zirconium tetrabutoxide, zirconium tetraacetylacetonate, zirconium dipropoxydiacetylacetonate and tributoxyzirconium acetylacetonate. Examples of the silane coupling agent include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris-2-methoxyethoxysilane, vinyltriacetoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrisilane. Methoxysilane, γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-2-aminoethylpropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-
Examples thereof include ureidopropyltrimethoxysilane and β-3,4-epoxycyclohexylethyltrimethoxysilane. The mixing ratio of the organic zirconium compound and the silane coupling agent is such that the Zr / Si molar ratio is
It is preferably in the range of 1/1 to 5/1. When the ratio of Zr is larger than the above range, the wettability at the time of applying the charge generation layer is deteriorated and a coating film having unevenness is formed. Further, if the proportion of Si exceeds the above range, the residual potential increases, which is not preferable.

On the other hand, it is also possible to use a mixture of an organic zirconium compound, a silane coupling agent and a binder resin. As the binder resin in this case, those mentioned above can be used. The mixing ratio of the binder resin with respect to the organic zirconium compound and the silane coupling agent is set as necessary. If a thicker undercoat layer is desired, increase the binder resin content and decrease the content. If you want one, you can reduce it. Further, an undercoat layer formed by mixing and dispersing a fine particle inorganic powder with the binder resin and applying and drying the dispersion liquid can also be used. As the fine particle inorganic powder, titanium oxide, antimony oxide, tin oxide, zinc oxide, alumina,
Indium oxide, magnesium oxide, silica, molybdenum trioxide, cupric oxide, etc. are used. In the present invention, the thickness of the undercoat layer is generally set to 0.01 to 5 μm, preferably 0.05 to 2 μm. In order to form the undercoat layer, a coating solution may be prepared. As the solvent, alcohols such as ethanol, methanol, propanol and butanol, ketones such as acetone and methyl ethyl ketone, aromatic carbonization such as toluene and xylene are used. Hydrogen, ethyl acetate, esters such as cellosolve acetate and the like can be used alone or in combination. When applying the coating liquid, the same coating method as described for the charge generation layer can be used, and the drying is 10 to 200.
℃, preferably at a temperature in the range of 30 ~ 180 ℃ 5 minutes ~
It can be carried out by blast drying for 6 hours, preferably 10 minutes to 2 hours or under static drying. Further, the electrophotographic photosensitive member of the present invention may be provided with a protective layer on the photosensitive layer for the purpose of improving printing durability.

[0014]

In the perylene pigment represented by the above general formula (1) in the present invention, the introduction of a heterocycle into the chemical structure causes the interaction between the donor and the acceptor between the hetero element and the carbonyl group. Therefore, it is presumed that a preferable molecular arrangement is formed, crystal growth in the dispersion is less likely to occur, and stability is increased. As a result, the perylene pigment has high photosensitivity and
A stable resin dispersion can be formed, and by using it, an excellent electrophotographic photoreceptor can be formed. The electrophotographic photosensitive member of the present invention is effectively used in an electrophotographic copying machine, but can be further applied to a laser beam printer, an LED printer, a CRT printer, a microfilm reader, a plain paper FAX, an electrophotographic plate making system, etc. Is.

[0015]

The present invention will be described in more detail with reference to the following examples. In the examples, "part" means "part by weight". Synthesis Example 1 (Synthesis of Compound 1) In a 100 ml flask, 5.0 parts of 3,4,9,10-perylenetetracarboxylic dianhydride, 5.1 parts of 2-aminothiazole and 70 ml of quinoline were placed, and under a nitrogen stream. The mixture was heated to reflux for 2.5 hours. After completion of the reaction, the mixture was cooled to room temperature, the produced crystals were filtered through a glass filter, further thoroughly washed with dimethylformamide (DMF) and then ethanol, and dried to obtain the compound No. 6.5 parts of 1 perylene pigment are obtained. The IR spectrum is shown in FIG. 2 parts of the obtained perylene pigment, 10 parts of salt,
Pellene pigment 1 finely pulverized with 27 10 mmφ menoballs placed in a 65 mmφ inner diameter pot, crushed with a planetary ball mill (P-5 type, manufactured by Fritsch) for 24 hours, thoroughly washed with distilled water, and dried. .9 parts were obtained. The powder X-ray diffraction pattern of the resulting perylene pigment is shown in FIG.
Shown in.

Synthetic Examples 2 to 7 In the same manner as in Synthetic Example 1, 3,4,9,10-perylenetetracarboxylic dianhydride was reacted with the corresponding amino compound, and the exemplified compound No. 3, 4, 6, 10, 14 and 16 perylene pigments were synthesized. Each IR spectrum is shown in FIGS. The resulting perylene pigment was pulverized in the same manner as in Synthesis Example 1. The powder X-ray diffraction patterns of each finely divided perylene pigment are shown in FIGS.

Example 1 A 50% toluene solution of tributoxyzirconium acetylacetonate (ZC540,
Matsumoto Kosho Co., Ltd.) 8 parts, γ-aminopropyltriethoxysilane (A1100, Nippon Unicar Co., Ltd.) 0.88 parts,
A solution obtained by mixing 36 parts of n-butyl alcohol and 18 parts of isopropyl alcohol was added to No. 3 was applied with a wire bar and dried at 150 ° C. for 10 minutes to form an undercoat layer. Next, polyvinyl butyral (S-REC BM-
0.5 parts of Sekisui Chemical Co., Ltd.) was added to 50 parts of n-butyl alcohol and dissolved by stirring to prepare a polyvinyl butyral solution. 1 part of this polyvinyl butyral solution
4.5 parts of mmφ glass beads and 0.04 part of the finely powdered perylene pigment obtained in Synthesis Example 1 were placed in a sample bottle having a volume of 8 ml, and dispersed with a paint shaker for 1 hour. This dispersion was placed on an aluminum plate on which the undercoat layer was formed. Apply with a wire bar of 5 and 10 at 100 ℃
The layer was dried to form a charge generation layer. Then, N, N'-
Diphenyl-N, N'-bis (3-methylphenyl)-
4 parts of [1,1′-biphenyl] -4,4′-diamine was used as a charge transport material and dissolved in 40 parts of monochlorobenzene together with 6 parts of the polycarbonate Z resin, and the resulting solution was added with No. Apply with 40 wire bar and 6 at 100 ℃
It was dried for 0 minutes to form a charge transport layer, and an electrophotographic photosensitive member was produced.

The electrical characteristics of the obtained electrophotographic photosensitive member were measured using a flat plate scanner in an environment of 20 ° C. and 50% RH. VDDP: Surface potential after 1 second when negatively charged by performing corona discharge of -25 μA dV / dE: 550 nm using bandpass filter
Attenuation rate of the potential when irradiated with the spectrally separated light VRP: After 10 seconds, white light of 50 ergs / cm ² was applied to 0.
Surface potential after irradiation for 5 seconds The results are shown in Table 2. The dispersion liquid for forming the charge generation layer was placed in a glass tube having an inner diameter of 3 mmφ, and the sedimentation speed of the pigment (length of clear supernatant portion) after one month was compared and used as an index of dispersibility. . Examples 2 to 7 As the charge generating material, compound No. 3, 4, 6, 10,
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the perylene pigment of 14 or 16 was used, and evaluated in the same manner. The results are shown in Table 2.

Comparative Example 1 A charge generating material was pulverized in the same manner as in Example 1,
4,9,10-Perylenetetracarboxylic acid-N, N'-
Evaluation was made in the same manner as in Example 1 except that diphenylimide was used. The results are also shown in Table 2.

[Table 2]

[0020]

INDUSTRIAL APPLICABILITY The perylene pigment having the above-mentioned specific structure in the present invention can be used to prepare a coating solution having a long pot life. Therefore, the electrophotographic photosensitive member of the present invention having a charge generation layer formed by using the
It exhibits high sensitivity and good electrophotographic characteristics.

[Brief description of drawings]

FIG. 1 is an IR spectrum diagram of a perylene pigment obtained in Synthesis Example 1.

2 is an IR spectrum diagram of a perylene pigment obtained in Synthesis Example 2. FIG.

FIG. 3 is an IR spectrum diagram of a perylene pigment obtained in Synthesis Example 3.

FIG. 4 is an IR spectrum diagram of a perylene pigment obtained in Synthesis Example 4.

5 is an IR spectrum diagram of the perylene pigment obtained in Synthesis Example 5. FIG.

FIG. 6 is an IR spectrum diagram of a perylene pigment obtained in Synthesis Example 6.

7 is an IR spectrum diagram of the perylene pigment obtained in Synthesis Example 7. FIG.

8 is a powder X-ray diffraction pattern of the perylene pigment obtained in Synthesis Example 1. FIG.

9 is a powder X-ray diffraction pattern of the perylene pigment obtained in Synthesis Example 2. FIG.

10 is a powder X of the perylene pigment obtained in Synthesis Example 3. FIG.
It is a line diffraction diagram.

11 is a powder X of the perylene pigment obtained in Synthesis Example 4. FIG.
It is a line diffraction diagram.

FIG. 12 is a powder X of the perylene pigment obtained in Synthesis Example 5.
It is a line diffraction diagram.

FIG. 13 is a powder X of the perylene pigment obtained in Synthesis Example 6.
It is a line diffraction diagram.

FIG. 14 is a powder X of the perylene pigment obtained in Synthesis Example 7.
It is a line diffraction diagram.

Claims (1)

[Claims] 1. An electrophotographic photoreceptor comprising a photosensitive layer formed on a conductive support, wherein the photosensitive layer contains at least one perylene pigment represented by the following general formula (1). Characteristic electrophotographic photoreceptor. [Chemical 1] (In the formula, R is X represents an alkyl group, an alkoxy group, a halogen atom or a nitro group, Y represents -S- or -NH-, and n means 0, 1 or 2. )