JPH05194523A - Production of new crystal of chlorogallium phthalocyanine and electrophotographic photoreceptor produced by using the crystal - Google Patents

Abstract

PURPOSE:To provide a process for the production of a new chlorogallium phthalocyanine crystal having a photo-sensitive wavelength range extended to a long-wavelength region and useful as a photo-conductive material for printer, etc., utilizing a semiconductor laser and to provide an electrophotographic photoreceptor containing the crystal. CONSTITUTION:New crystal of chlorogallium phthalocyanine having strong diffraction peaks at least at 7.4 deg., 16,6 deg., 25.5 deg. and 28.3 deg. (Bragg angle, 2theta+ or -0.2 deg.) in X-ray diffraction spectrum can be produced by mechanically crushing a chlorogallium phthalocyanine crystal and treating with an aromatic alcohol solvent. The electrophotographic photoeceptor is produced by covering an electrically conductive substrate with a photo-sensitive layer containing the chlorogallium phthalocyanine crystal. The electrophotographic photoreceptor containing the crystal in the photo-sensitive layer has high sensitivity, low residual charge, high charge-accumulation property and excellent durability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a novel crystal of chlorogallium phthalocyanine and an electrophotographic photoreceptor using a photoconductive material comprising the crystal.

[0002]

2. Description of the Related Art Conventionally, various materials have been proposed as a photosensitive material for an electrophotographic photosensitive member, and a laminated electrophotographic photosensitive member in which a photosensitive layer is separated into a charge generating layer and a charge transporting layer. Also, various organic compounds have been proposed as charge generation materials. In recent years, there has been an increasing demand for extending the photosensitive wavelength range of conventionally proposed organic photoconductive materials to the wavelength (780 to 830 nm) of semiconductor lasers in the near-infrared region and using it as a photoconductor for digital recording such as laser printers. From this viewpoint, the squarylium compound (JP-A-49-105536 and JP-A-58-21416) is used.
JP-A No. 61-151659), phthalocyanine compounds (JP-A Nos. 48-34189 and 57-14874).
No. 5) has been proposed as a photoconductive material for semiconductor lasers.

When an organic photoconductive material is used as a photosensitive material for a semiconductor laser, first, the photosensitive wavelength range is extended to a long wavelength, then, the sensitivity of the photosensitive member to be formed,
Good durability is required. The above-mentioned organic photoconductive material does not sufficiently satisfy these conditions.
In order to overcome these drawbacks, the relationship between the crystal type and the electrophotographic characteristics of the above-mentioned organic photoconductive material has been studied, and many reports have been made on phthalocyanine compounds.

It is known that phthalocyanine compounds generally show several crystal types depending on the production method and treatment method, and the difference in the crystal types has a great influence on the photoelectric conversion characteristics of the phthalocyanine compound. Regarding the crystal form of the phthalocyanine compound, for example, looking at copper phthalocyanine, in addition to the stable β form, α, ε, π,
Crystal forms such as x, ρ, γ, and δ are known. It is known that these crystal forms can be transferred to each other by mechanical strain, sulfuric acid treatment, organic solvent treatment, heat treatment, or the like. (For example, US Pat. Nos. 2,770,629 and 3,1).
No. 60,635, No. 3,708,292 and No. 3,
357,989). In addition, JP-A-50-385
Japanese Patent Laid-Open No. 43-43, regarding the difference in crystal type of copper phthalocyanine and the electrophotographic characteristics, in comparison of α, β, γ and ε types,
It is described that the ε type exhibits the highest sensitivity.

Regarding the chlorogallium phthalocyanine, the crystal form of chlorogallium phthalocyanine having a specific Bragg angle is described in Journal of Electrophotography, 26 (3), 240 (1987). Has a different crystal form, and there is no description of application to electrophotography. On the other hand, JP-A-59-44053,
The Shinkyo Giho CPM 81-69, 39 (1981), etc.
Application to electrophotography is described, and JP-A-1-221
459 discloses a chlorogallium phthalocyanine having a specific Bragg angle and an electrophotographic photoreceptor using the same.

[0006]

However, not only the above-mentioned chlorogallium phthalocyanines, but also the phthalocyanine compounds proposed hitherto have been sufficiently satisfactory in terms of photosensitivity and durability when used as a photosensitive material. Not only that, but also in the production thereof, there are problems that the crystal type conversion operation is complicated and the crystal type is difficult to control.

The present invention has been made in view of the above problems in the prior art. That is, an object of the present invention is to provide a method for producing a novel crystal of chlorogallium phthalocyanine. Another object of the present invention is to provide an electrophotographic photoreceptor containing a novel crystal of chlorogallium phthalocyanine as a photoconductive material, which has high sensitivity and excellent durability, in a photosensitive layer.

[0008]

Means for Solving the Problems The inventors of the present invention have earnestly studied phthalocyanine photoconductive materials, and as a result, after mechanically crushing crude chlorogallium phthalocyanine obtained by synthesis, a solvent treatment that promotes crystal growth was performed. When attached,
It was found that the characteristics as a photoconductive material were completely different depending on the type of solvent even though they were the same crystal type, and they were obtained by mechanically crushing the above crude crystals and then treating them with a specific organic solvent. It was confirmed that the novel crystal of chlorogallium phthalocyanine exhibited a very excellent performance as a photoconductive material for an electrophotographic photoreceptor,
The present invention has been completed. That is, according to the present invention, chlorogallium phthalocyanine is mechanically crushed and then treated with an aromatic alcohol so that the Bragg angle (2θ ± 0.2 °) in the X-ray diffraction spectrum is at least 7.4. °, 16.6 °, 25.5 ° and 28.
It is a method for producing a novel crystal of chlorogallium phthalocyanine having a strong diffraction peak at 3 °. The present invention also resides in an electrophotographic photosensitive member obtained by coating a conductive support with a photosensitive layer containing the novel crystal of chlorogallium phthalocyanine.

The present invention will be described in detail below. The chlorogallium phthalocyanine used in the present invention can be synthesized, for example, by a known method in which phthalonitrile or diiminoisoindoline and gallium trichloride are reacted in an organic solvent such as α-chloronaphthalene or quinoline.

As means for mechanically pulverizing the chlorogallium phthalocyanine obtained by the above method, an automatic mortar, a kneader, a planetary ball mill, a vibrating ball mill, C
Devices such as F mills and roller mills can be used, but are not limited to these. If necessary, it is also possible to use a grinding aid that can be easily removed after grinding, such as sodium chloride and sodium sulfate.

The aromatic alcohols used in the present invention include benzyl alcohol, phenethyl alcohol and α-
Examples thereof include phenylethyl alcohol and m-tolylcarbinol. In the solvent treatment, the use ratio of the chlorogallium phthalocyanine crystal and the aromatic alcohol is not particularly limited, but if the contact efficiency between the two is 1: 5:
A range of 100 is preferred. The treatment temperature of the chlorogallium phthalocyanine and the aromatic alcohol is 0 ° C to
The temperature is 200 ° C, preferably 20 to 150 ° C. If the treatment temperature is too high, part of the phthalocyanine may be decomposed, while if it is too low, it takes a long time for the crystal conversion to proceed, which is not practical. The treatment time depends on the treatment temperature and the amount of aromatic alcohol used.
~ 50 hours are preferred. The treatment method is not particularly limited, but a method of wet milling or mixing in a stirring tank by a known method using a ball mill, an attritor, a sand mill or the like together with grinding media such as glass beads, steel beads, and alumina beads is used. preferable.

In the treatment method as described above, although the above-mentioned chlorogallium phthalocyanine has the same crystal type, the characteristics as a photoconductive material are completely different depending on the type of solvent. Direction of crystal growth based on the difference in the dissolving power to the chlorogallium phthalocyanine crystal,
It is presumed that the crystal surface defects are slightly different due to the difference in growth rate. In particular, the chlorogallium phthalocyanine crystal obtained by treating with the aromatic alcohol of the present invention has a Bragg angle (2θ ± 2) in the X-ray diffraction spectrum.
0.2 °) is 7.4 °, 16.6 °, 25.5 ° and 2
It has a strong diffraction peak at 8.3 °, and as is clear from Table 1 described later, it exhibits very excellent performance as a novel photoconductive material for electrophotographic photoreceptors.

Next, an electrophotographic photosensitive member using the above chlorogallium phthalocyanine crystal as a photoconductive material in the photosensitive layer will be described. The electrophotographic photosensitive member of the present invention may have a single-layered photosensitive layer or a laminated structure in which a charge generation layer and a charge transport layer are functionally separated. When the photosensitive layer has a laminated structure, the charge generation layer is composed of the chlorogallium phthalocyanine crystal and the binder resin.

The binder resin can be selected from a wide range of resins. Preferred binder resins are polyvinyl butyral, polyarylate (polycondensate of bisphenol A and phthalic acid, etc.), polycarbonate, polyester, phenoxy resin, chloride. Insulating resins such as vinyl-vinyl acetate copolymer, polyvinyl acetate, acrylic resin, polyacrylamide, polyamide, polyvinyl pyridine, cellulosic resin, urethane resin, epoxy resin, casein, polyvinyl alcohol, polyvinyl pyrrolidone can be mentioned. .. It can also be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene and polyvinylpyrene.

The charge generation layer can be formed by dispersing a chlorogallium phthalocyanine crystal in a solution prepared by dissolving the above-mentioned binder resin in an organic solvent to prepare a coating solution, and coating the solution on a conductive support. it can. In that case, the compounding ratio (weight) of the chlorogallium phthalocyanine crystal used and the binder resin is 40: 1 to 1:10, preferably 10: 1 to 1: 4. If the ratio of the chlorogallium phthalocyanine crystals is too high, the stability of the coating solution will decrease, while if it is too low, the sensitivity will decrease, so it is preferable to set the above range.

The solvent used is preferably selected from those which do not dissolve the undercoat layer or charge transport layer described later. Specific organic solvents include alcohols such as methanol, ethanol and isopropanol, acetone,
Ketones such as methyl ethyl ketone and cyclohexanone,
N, N-dimethylformamide, N, N-dimethylacetamide and other amides, dimethyl sulfoxide and other sulfoxides, tetrahydrofuran, dioxane, ethylene glycol monomethyl ether and other ethers, methyl acetate,
Esters such as ethyl acetate, methylene chloride, chloroform, carbon tetrachloride, aliphatic halogenated hydrocarbons such as dichloroethylene and trichlorethylene, mineral oil such as ligroin, aromatic hydrocarbons such as benzene, toluene and xylene, chlorobenzene and dichloroethylene. Aromatic halogenated hydrocarbons such as chlorobenzene can be used.

The coating liquid may be applied by a dipping coating method, a spray coating method, a spinner coating method, a bead coating method, a Meyer bar coating method, a blade coating method, a roller coating method, a curtain coating method, or the like. it can. In addition, the drying is performed after touch drying at room temperature,
A method of heating and drying at a temperature of ˜200 ° C. for 5 minutes to 2 hours in a static state or under blowing air is preferable. Then, the charge generation layer is usually applied so as to have a thickness of about 0.05 to 5 μm.

The charge transport layer is composed of a charge transport material and a binder resin. Examples of the charge transport material include polycyclic aromatic compounds such as anthracene, pyrene, and phenanthrene,
Nitrogen-containing heterocyclic compounds such as indole, carbazole and imidazole, pyrazoline compounds, hydrazone compounds, triphenylmethane compounds, triphenylamine compounds,
Any known compounds such as enamine compounds and stilbene compounds can be used. Furthermore, poly-N-vinylcarbazole, halogenated poly-
Examples include photoconductive polymers such as N-vinylcarbazole, polyvinylanthracene, poly-9-vinylphenylanthracene, polyvinylpyrene, polyvinylacridine, polyvinylacenaphthylene, polyglycidylcarbazole, pyrene-formaldehyde resin, and ethylcarbazole-formaldehyde resin. , They may form the layer by themselves. Further, as the binder resin, the same insulating resin as that used for the charge generation layer can be used.

The charge transport layer can be formed by preparing a coating solution using the above charge transport material, a binder resin and the same organic solvent as described above, and then coating the same by the same method as described above. The compounding ratio (weight) of the charge transport material and the binder resin is usually set in the range of 5: 1 to 1: 5. The thickness of the charge transport layer is usually set to about 5 to 50 μm.

In the case where the electrophotographic photoreceptor has a single layer structure, the photosensitive layer comprises a photoconductive layer in which the above-mentioned chlorogallium phthalocyanine crystal is dispersed in a binder resin containing a charge transporting material, and the charge transporting material is used. The same material as described above is used as the binder resin. In that case, the compounding ratio (weight) of the charge transport material and the binder resin is 1:20 to 5: 1, and the compounding ratio (weight) of the chlorogallium phthalocyanine crystal and the charge transport material is about 1:10 to 10: 1. Is preferably set, and the photosensitive layer is formed in the same manner as described above.

As the conductive support, any material can be used as long as it is known to be used as an electrophotographic photoreceptor.

In the present invention, an undercoat layer may be formed on the conductive support. The undercoat layer is effective for preventing unnecessary injection of electric charges from the conductive support, and has the function of enhancing the chargeability of the photosensitive layer. Further, it also has the function of enhancing the adhesion between the photosensitive layer and the conductive support. As the material constituting the undercoat layer, polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl pyridine, cellulose ethers, cellulose esters, polyamides, polyurethanes,
Organic zirconium compounds such as casein, gelatin, polyglutamic acid, starch, starch acetate, amino starch, polyacrylic acid, polyacrylamide, zirconium chelate compounds and zirconium alkoxide compounds, organic titanyl compounds such as titanyl chelate compounds and titanyl alkoxide compounds, silane cups Examples include ring agents. The thickness of the undercoat layer is preferably set to about 0.05 to 2 μm.

[0023]

EXAMPLES The present invention will be specifically described below with reference to examples. In addition, in an Example and a comparative example, "part" means a weight part. Example of synthesis of chlorogallium phthalocyanine 30 parts of 1,3-diiminoisoindoline and 9.1 parts of gallium trichloride were added to 230 parts of quinoline and the temperature was adjusted to 200 ° C.
After reacting for 3 hours in, the product was filtered, washed with acetone and methanol, and then the wet cake was dried to obtain 28 parts of chlorogallium phthalocyanine crystals. The powder X-ray diffraction pattern of the obtained chlorogallium phthalocyanine crystal is shown in FIG.

Example 1 Chlorogallium phthalocyanine 3 obtained in the above synthesis example
Part 0 is a planetary ball mill (Flish Co .: P-5 type)
20 mmφ agate balls (200 parts) and 10 mmφ agate balls (100 parts) were ground together for 20 hours. The powder X-ray diffraction pattern of this ground chlorogallium phthalocyanine crystal is shown in FIG. Next, 25 parts of this crystal was ball-milled with 300 parts of 1 mmφ glass beads and 400 parts of benzyl alcohol at room temperature for 12 hours, filtered, washed with 500 parts of methanol, and the obtained wet cake was dried under reduced pressure to obtain chlorogallium. A phthalocyanine crystal was obtained. The crystal size of the obtained crystal was about 0.05 to 0.15 μm, and the crystal had an extremely uniform shape. The powder X-ray diffraction pattern is shown in FIG.

Example 2 200 parts of 1.0 part of chlorogallium phthalocyanine and 30 parts of benzyl alcohol ground in the same manner as in Example 1 were used.
After stirring in a ml reaction flask at 60 ° C. for 1.5 hours,
The crystal was washed with 50 parts of methanol and dried under reduced pressure to obtain a chlorogallium phthalocyanine crystal. The crystal size of the obtained crystal was about 0.05 to 0.15 μm, and the crystal had an extremely uniform shape. The powder X-ray diffraction pattern is shown in FIG.

Example 3 20 parts of chlorogallium phthalocyanine crystal ground by the same method as in Example 1 was added to 250 parts of 1 mmφ glass beads,
After ball milling at room temperature for 12 hours together with 350 parts of m-tolylcarbinol, it was filtered and washed with 500 parts of methanol, and the obtained wet cake was dried under reduced pressure to obtain chlorogallium phthalocyanine crystals. The powder X-ray diffraction pattern of the obtained chlorogallium phthalocyanine crystal is shown in FIG.

Comparative Example 1 0.5 part of chlorogallium phthalocyanine crystal ground in the same manner as in Example 1 was added to 60 parts of 1 mmφ glass beads,
After ball milling with 20 parts of chlorobenzene at room temperature for 24 hours, the mixture was filtered and washed with 500 parts of methanol, and the obtained wet cake was dried under reduced pressure to obtain chlorogallium phthalocyanine crystals. The powder X-ray diffraction pattern of the obtained chlorogallium phthalocyanine crystal is shown in FIG.

Comparative Example 2 25 parts of chlorogallium phthalocyanine crystal ground in the same manner as in Example 1 was added with 300 parts of 1 mmφ glass beads,
After ball-milling with 300 parts of dimethylformamide for 24 hours at room temperature, it was filtered and washed with 500 parts of methanol, and the obtained wet cake was dried under reduced pressure to obtain chlorogallium phthalocyanine crystals. The powder X-ray diffraction pattern of the obtained chlorogallium phthalocyanine crystal is shown in FIG.

Comparative Example 3 0.5 part of chlorogallium phthalocyanine crystal ground in the same manner as in Example 1 was added to 60 parts of 1 mmφ glass beads,
After ball milling with 20 parts of ethylene glycol at room temperature for 20 hours, the mixture was filtered, washed with 500 parts of methanol, and the obtained wet cake was dried under reduced pressure to obtain chlorogallium phthalocyanine crystals. The powder X-ray diffraction pattern of the obtained chlorogallium phthalocyanine crystal is shown in FIG.

Examples 4 to 6 1 part of the chlorogallium phthalocyanine crystals obtained in each of Examples 1 to 3 was mixed with 1 part of polyvinyl butyral (Sekisui Chemical Co., Ltd .: S-REC BM-1) and 100 parts of cyclohexanone to prepare glass. After treatment with beads by a paint shaker for 1 hour to disperse, the obtained coating solution is applied on an aluminum substrate by a dip coating method, and dried by heating at 100 ° C. for 5 minutes to give a film thickness of 0.2 μm.
m charge generating layer was formed.

Next, the following structural formula

[Chemical 1] N, N'-diphenyl-N, N'-bis-
2 parts of (m-tolyl) benzidine

The following structural formula

[Chemical 2] 3 parts of poly [1,1-di- (p-phenylene) cyclohexanecarbonate] represented by are dissolved in 20 parts of chlorobenzene, and the obtained coating solution is applied onto an aluminum substrate on which a charge generation layer is formed by dip coating Apply with 1
It was heated and dried at 20 ° C. for 1 hour to form a charge transport layer having a film thickness of 20 μm.

The electrophotographic characteristics of the electrophotographic photosensitive member produced as described above were measured as follows. Using an electrostatic copying paper tester (Kawaguchi Electric Co., Ltd .: EPA-8100), the environment is kept at room temperature and normal humidity (20 ° C., 50% RH).
After charging the photoreceptor by KV corona discharge, the light from the tungsten lamp is used for 800 with a monochromator.
nm monochromatic light, 1 μW / cm ² on the surface of the photoconductor
It was adjusted so that Then, the exposure amount E until the surface potential becomes half of the initial V ₀ (volt)
_The residual potential V _R was measured by measuring _1/2 (erg / cm ² ) and then irradiating the surface of the photoreceptor with 10 lux of tungsten light for 1 second. Furthermore, the above charging and exposure are performed for 10
After repeating 00 times, V _O , E _1/2 and V _R were measured.
The results are shown in Table 1 below together with Comparative Examples 4 to 6 below.

Comparative Example 4 An electrophotographic photosensitive member produced by forming a charge generation layer and a charge transport layer in the same manner as in Example 4 except that the chlorogallium phthalocyanine crystal obtained in Comparative Example 1 was used. Evaluation was carried out in the same manner as in Example 4.

Comparative Example 5 An electrophotographic photosensitive member produced by forming a charge generation layer and a charge transport layer in the same manner as in Example 4 except that the chlorogallium phthalocyanine crystal obtained in Comparative Example 2 was used. Evaluation was carried out in the same manner as in Example 4.

Comparative Example 6 An electrophotographic photosensitive member produced by forming a charge generation layer and a charge transport layer in the same manner as in Example 4 except that the chlorogallium phthalocyanine crystal obtained in Comparative Example 3 was used. Evaluation was carried out in the same manner as in Example 4.

[0037]

[Table 1]

[0038]

INDUSTRIAL APPLICABILITY According to the present invention, a novel crystal of chlorogallium phthalocyanine having a strong peak at a specific Bragg angle in an X-ray diffraction spectrum can be obtained by a simple production method of treating with an aromatic alcohol after mechanical grinding. Since the obtained crystal has a photosensitive wavelength region extending to a long wavelength, it is very useful as a photoconductive material for an electrophotographic photoreceptor such as a printer using a semiconductor laser. Further, as is clear from Table 1 above, the electrophotographic photoreceptor of the present invention produced by using the chlorogallium phthalocyanine crystal having the above crystal form has high sensitivity, low residual potential, and high chargeability, Moreover, since it is less likely to deteriorate even after repeated copying, it can be used as a highly durable photoconductor.

[Brief description of drawings]

FIG. 1 shows a powder X-ray diffraction diagram of chlorogallium phthalocyanine obtained in a synthesis example.

2 shows a powder X-ray diffraction pattern of the ground chlorogallium phthalocyanine crystals of Example 1. FIG.

FIG. 3 shows a powder X-ray diffraction pattern of the chlorogallium phthalocyanine crystal obtained in Example 1.

4 shows a powder X-ray diffraction diagram of the chlorogallium phthalocyanine crystal obtained in Example 2. FIG.

5 shows a powder X-ray diffraction pattern of the chlorogallium phthalocyanine crystal obtained in Example 3. FIG.

FIG. 6 shows a powder X-ray diffraction pattern of the chlorogallium phthalocyanine crystal obtained in Comparative Example 1.

FIG. 7 shows a powder X-ray diffraction pattern of the chlorogallium phthalocyanine crystal obtained in Comparative Example 2.

FIG. 8 shows a powder X-ray diffraction pattern of the chlorogallium phthalocyanine crystal obtained in Comparative Example 3.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Imai 1600 Takematsu, Minamiashigara City, Kanagawa Prefecture Fuji Xerox Co., Ltd. Takematsu Office

Claims (2)

[Claims] 1. A Bragg angle (2θ ± 0.2 °) in an X-ray diffraction spectrum of at least 7. characterized in that chlorogallium phthalocyanine is mechanically ground and then treated with aromatic alcohols. 4 °, 16.6
A method for producing a chlorogallium phthalocyanine crystal having strong diffraction peaks at °, 25.5 ° and 28.3 °. 2. An electrophotographic photosensitive member comprising a conductive support and a photosensitive layer containing the chlorogallium phthalocyanine crystal according to claim 1 coated on the conductive support.