JPS59155846A - Manufacture of electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain a photosensitive body high in sensitivity by coating a substrate with a dispersion obtained by dispersing into a binder resin together with a specified solvent, a phthalocyanine pigment substd. by an electron attractive group prepd. by mixing it with an inorg. acid, and precipitating it with water or a basic substance. CONSTITUTION:Phthalocyanine (Pc) or a Pc deriv. having its benzene ring substd. by an electron attractive group, such as nitro or halogen, is mixed with an inorg. acid capable of forming a salt with it, and pptd. by using water or a basic material, such as ammonia to obtain a Pc type pigment. A dispersing solvent, such as alcohols, not causing transition of crystals is added and the pigment is dispersed into a binder resin, a conductive substrate is coated with the coating dispersion thus obtained, and dried and solidified to obtain an electrophotographic sensitive body. The use of such a dispersion solvent not causing crystal transition does not convert the Pc compd. into a stable type, and it can be dispersed into the binder resin in a state stable in electrostatic characteristics, and a photosensitive body high in sensitivity is obtained.

Description

Detailed Description of the Invention The present invention involves dispersing an unstable or metastable phthalocyanine pigment in a binder resin by adding a dispersion solvent, applying the coating liquid to a tetraelectric support, and drying it. The present invention relates to a method for manufacturing an electrophotographic photoreceptor that is solidified.

In the above method for producing a photoreceptor, when an unstable or metastable phthalocyanine pigment is used as the photoconductive powder, crystallization transitions to a stable type between the time it is applied to the conductive support and the time it is dried and solidified. It is generally believed that the electrostatic properties of the manufactured photoreceptor are unstable and that it is difficult to manufacture a photoreceptor with predetermined electrostatic characteristics. For example, use a solvent that actively causes crystal transition to a stable form, such as an aromatic solvent such as toluene or xylene, an aliphatic hydrocarbon solvent, or a ketone solvent such as acetone or methyl ethyl ketone. It was used as a dispersion solvent. Also, these! The reality is that it has been considered an unstable or metastable type since the 4th Qing.

In view of the above points, the present invention examines the sensitivity of various phthalocyanine pigments, finds a phthalocyanine pigment with excellent sensitivity, and creates a highly sensitive photoreceptor that makes good and full use of its characteristics. The purpose is to make it possible to obtain.

Electrophotographic photoreceptor according to the present invention! ! ! In order to achieve the above object, the phthalocyanine and the benzene nucleus of the phthalocyanine molecule are substituted with at least one electron-withdrawing group selected from a nitro group, a cyano group, a halogen atom, a sulfone group, and a carboxyl group. The resulting phthalocyanine derivative is mixed with an inorganic acid that can form a salt with phthalocyanine, and then dispersed in water and a basic substance in a binder resin, and the coating solution is applied to a conductive support and dried. It is characterized by solidification.

In other words, as a result of considering the sensitivity of various phthalocyanine pigments, we found that the phthalocyanine pigments obtained as described above have far superior sensitivity compared to conventional ones. It was discovered that the sensitivity decreases when the crystal transitions to a stable type. Because it reliably prevents crystal transition to a stable form during coating on a static support and dry solidification i+4, it does not undergo crystal transition to a stable form and is dispersed in a binder resin with stable electrostatic properties. Breaking away from the conventional idea that a stable type is better, and by appropriately selecting a dispersing solvent, a photoreceptor with extremely high sensitivity was obtained.

metal phthalocyanines such as iron, sodium, lithium, calcium, and magnesium, or mixtures thereof.

The benzene nucleus of the phthalocyanine molecule is substituted with at least seven types of electron-withdrawing groups selected from nitro groups, cyano groups, halogen atoms, sulfone groups, and carboxyl groups.

This phthalocyanine derivative is used during phthalocyanine synthesis.
As phthalonitrile, phthalic acid, phthalic anhydride, and phthalimide, which are raw materials for phthalocyanine, phthalonitrile, phthalic acid, phthalic anhydride, and phthalimide substituted with the above substituents are used, or by using a part of them together. q・Can be done.

Examples of inorganic acids that can form salts with the phthalocyanine used in the present invention include sulfuric acid, orthophosphoric acid, pyrophosphoric acid, talolosulfonic acid, m-acid, iodohydric acid, hydrofluoric acid, and hydrobromic acid. . These inorganic acids are those used in conventionally known methods such as phthalocyanine acid pasting method and acid slurry method. As for the cutting method, conventionally known methods can be applied. For example, a method of dissolving phthalocyanine in the above-mentioned inorganic acid and then injecting the solution into water etc. (acid pasting method), a method of making a slurry of an inorganic acid salt of phthalocyanine and injecting it into water etc. (acid slurry method), There is a method of decomposing an inorganic acid salt of phthalocyanine with a basic substance such as ammonia gas to precipitate phthalocyanine.

Solvacedate), ester solvents such as butyl acetate, alcohol solvents such as n-butanol, methanol, ethanol, n-propertool, n-pentanol,
Alternatively, ethylene glycol monoethyl ether (ethyl cellosol), which is a part of ether solvents,
Ethylene glycol mobutyl ether or a mixed solvent thereof can be used. However, when using the above-mentioned ethylene glycol monoethyl ether acetate, there is a risk that crystal transition will progress, albeit gradually, if it is stored as a coating solution, so it should not be applied to the conductive support early after the coating solution is prepared. There is a need to. On the other hand, alcohol-based solvents do not undergo crystal transition even when stored as a coating solution for more than 1 month, and it is preferable to use alcohol-based solvents as the dispersion solvent.

In addition, 3"11 resins include electrically insulating thermoplastic resins, thermosetting resins, and PVK resins that are known per se.
It is possible to use two-pronged binder I'M resin such as light guide resin, photocurable resin, etc., and suitable specific examples include Satsuki 1 polyester + Moonshi, Polyamide 4 Polyester + Hot white plastic J1 raw materials such as acrylic wood, ethylene-vinyl acetate copolymer, ethylene-butadiene copolymer, polycarbonate x, vinyl chloride, vinyl acetate co-Mf&IF, cellulose ester, polyamide, etc. SuhJ Monthly,
Epoxy 8r11 effect, Frethane (sealing effect, silicone sealing effect, phenol hand sealing fat, melamine 41.11 yen,
A thermosetting binder resin such as a thermosetting acrylic resin, an alkyd resin, or a xylene resin, preferably a thermosetting acrylic resin.

In carrying out the present invention, the phthalocyanine pigment and dispersion solvent according to the present invention may be ground and dispersed in advance prior to dispersion in the binding-AIJ resin. This method has the advantage that the sensitivity can be approximately doubled compared to the case where all three binder resins are dispersed at once.

Examples, comparative examples, and experimental results will be described below.

Example 1 0 parts by weight of copper phthalocyanine and 0.5 parts by weight of tetranitrocopper phthalocyanine were dissolved in 2j' concentrated sulfuric acid and 1 part of SOO melon while thoroughly stirring and mixing, and then the solution was dissolved in water.
00 (add 1 part by weight, precipitate a composition of copper phthalocyanine and tetranitro copper phthalocyanine, then filter and wash with water), and thermosetting raw acrylic resin (Acrydec A405: manufactured by Dainippon Ink Co., Ltd.). Mixed solvents (n-butanol: cellosolve acetate (manufactured by Nagase Sangyo Co., Ltd.) = 1:
1) was added as a dispersion solvent and divided for 2 hours using an attritor to prepare a coating solution. After adjusting the viscosity, it was applied to a conductive support by spraying, and the dry film thickness was about /jO0C. A 10 μm photoreceptor was produced.

Comparative Example A photoreceptor was produced in the same manner as in Example 1, except that a mixed solvent (xylene: n-zucnol: cellosolve acetate = 1:1:1) was used as the dispersion solvent. When the coating liquid obtained in this comparative example was observed with an optical microscope,
j~! A needle strain of μ was observed, and X-rays confirmed that it was a stable β type. This is unstable due to xylene! ! ;'! This is because the steel phthalocyanine has been crystallized into a stable form with dispersion.

Regarding Example 1 and It Comparative Example, the surface potential (VO), the half-decreased exposure dose (E'/2), the exposure dose required for the initial surface potential to become 300 V (E3θO), and the dark decay rate (DD
Rl) When the dogs were measured, the results shown in the following table were obtained.

v; Table 1 From the above results, it is clear that the photoreceptor of Example 1 has excellent sensitivity, low dark decay rate, and extremely good electrostatic properties.

Example 2 The same copper phthalocyanine and resin as in Example 1 were mixed so that the Bakugou ratio was 10-, and the same mixture as in Example 1 was added so that the solid ratio (copper phthalocyanine + resin) was 20%. A solvent was added and dispersed in a ball mill for about 2 days to prepare a 1-shin Kokyuyo coating liquid. A comparison was made between a photoreceptor in which the viscosity of the thus prepared coating liquid was immediately adjusted and applied, and a photoreceptor in which the viscosity was adjusted and applied after being left for a month. Incidentally, needle-like bodies were observed in the solution after 1 month, indicating that the crystal transition to a stable form was proceeding.

The surface potential (VO), half-decrease exposure (E/Δ), dark decay rate (DDRl), and total current flowing through the charger (I t ) of the above two types of photoreceptors were measured, and the results are shown in the following table. Got the results.

Table 2 Example 3 The same unstable copper phthalocyanine as in Example 1, Zutilal resin (5-LECBXL: Tanesui Chemical Co., Ltd. W>) and melamine resin (Super Beckamine J820, Dainippon Ink (
Co., Ltd.) in a ratio of (7:3) so that the Bakugou ratio is jO, and then add n- so that the solid ratio (copper phthalocyanine + butyral resin and melamine) is in the 2θ ratio. Butanol was added and dispersed for about 2 days, and the resulting coating solution was coated onto an aluminum conductive support and dried and solidified at about /jθ℃ to prepare a photoreceptor with a dry film thickness of about 70μ. did. It should be noted that the above coating liquid showed no needle-like objects even after being left for several months, and it was clear that the coating liquid had excellent storage stability. When the electrostatic properties of the above photoreceptor were measured, it was found that Vo+:J was oV
E, /2: fjjLux-sec, DDR,
: , 2o% was obtained, and no change was observed even after 1 month.

Example 4 Ethyl cellosolve (manufactured by Wako Tsumugi Co., Ltd.) as a dispersion solvent:
A coating liquid was prepared in the same manner as in Example 2 except that a mixed solvent of 1:1 (1st class): n-butanol was used, and the coating liquid was applied onto an aluminum conductive support by blade coating. The photoconductor was dried and solidified to have a dry film thickness of approximately 10 μm. Furthermore, for comparison, Bakugou was ground and dispersed in advance for 7 days using only a mixed solvent, then added to a binder resin and dispersed for 7 days, and the resulting coating liquid was coated with aluminum conductive material by grade coating. A photoreceptor was prepared by distributing the photoreceptor on a transparent support and drying and solidifying it so that the dry film thickness was about 10 μm. Regarding the above two types of photoreceptors,
When the electrostatic properties and the change in the surface ↑ (△■) after 20 copies were measured as repeated properties, the results shown in the following table were obtained.

From the results in Section 2, it is clear that although the repeatability is worse, the pre-dispersion is much better in terms of sensitivity.

Example 5 A photoreceptor was prepared in the same manner as in Example 2 except that ethyl soap was used as the dispersion solvent, and the electrostatic properties and repeatability were measured in the same manner as in Example 4. The results are shown in the following table. Got the results.

Continuation of page 1 (t-2) Inventor Mitsutoshi Sakamoto Osaka Kokusai Building, 2-30 Azuchi-cho, Higashi-ku, Osaka City Minolta Camera Co., Ltd. Inventor Hideaki Ueda Osaka Kokusai Building, 2-30 Azuchi-cho, Higashi-ku, Osaka City Minolta Camera Co., Ltd. Applicant: Toyo Ink Manufacturing Co., Ltd. 2-3-13 Kyobashi, Chuo-ku, Tokyo

Claims (1)

[Scope of Claims] ■ Phthalocyanine and phthalocyanine derivatives in which the benzene nucleus of the phthalocyanine molecule is substituted with at least one electron-withdrawing group selected from a nitro group, a cyano group, a halogen atom, a sulfone group, and a carboxyl group, A method for producing an electrophotographic photoreceptor, in which the mixture is mixed with an inorganic acid capable of forming a salt, dispersed in a binder resin using water or a basic substance, and the coating solution is applied to a conductive support and dried and solidified. . (2;) The manufacturing method according to claim 2, wherein the dispersion solvent is an alcoholic solvent.