JPS59157649A - Manufacture of electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance sensitivity by using an instable type or metastable type phthalocyanine for a photosensitive body. CONSTITUTION:Phthalocyanine or a phthalocyanine deriv. substd. by at least one kind of group selected from nitro, cyano, halogen, sulfo, or carboxy, at the benzene ring of its molecule is mixed with an inorg. acid capable of forming a salt with phthalocyanine. Then, a phthalocyanine type pigment obtained by precipitating it with water or a basic substance is pulverized and dispersed together with a type of monomer not causing crystal transition, and a dispersing solvent, such as alcohols, not causing crystal transition is added to this mixture, and again dispersed into a binder resin to obtain a coating material. The photosensitive body obtained by coating a conductive substrate with this material and drying it can be prevented from transition to stable type crystals low in sensitivity.

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, and applying the coating liquid to a conductive support and drying and solidifying it. When a stable or metastable phthalocyanine pigment is used in the production of an electrophotographic photoreceptor, it undergoes a crystal transition to a stable form after it is applied to a conductive support and before it is dried and solidified. It is generally believed that the electrostatic properties of photoreceptors are unstable and it is difficult to manufacture photoreceptors with predetermined electrostatic properties.
Conventionally, in order to obtain a stable crystal transition state as a coating liquid, for example, aromatic solvents such as toluene and xylene, aliphatic hydrocarbon purple solvents, and ketone solvents such as acetone and methyl ethyl ketone have been used. A solvent that actively promotes crystal transition to a stable form was used as a dispersion solvent. Furthermore, due to these circumstances, it is actually believed that stable phthalocyanine pigments have better sensitivity than unstable or metastable phthalocyanine pigments.

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

In order to achieve the above-mentioned object, the method for producing an electrophotographic photoreceptor according to the present invention includes a phthalocyanine and a benzene nucleus of the phthalocyanine molecule containing at least one type of nitro group, cyano group, halogen atom, sulfone group, and carboxyl group. Amorphous phthalocyanine pigment obtained by mixing a phthalocyanine derivative substituted with an electron-withdrawing group with an inorganic acid capable of forming a salt with 7-lysocyanine and precipitating it with water or a basic substance. After pulverizing and dispersing with the upper normer, the mixture J% and a dispersion solvent that does not cause transition are added and dispersed in a binder resin, and the coating liquid is applied to a conductive support and dried and solidified. shall be.

In other words, as a result of considering the sensitivity of various 7-thalocyanine pigments, we found that the phthalocyanine pigment obtained as described above has far superior sensitivity compared to conventional pigments, and furthermore, this phthalocyanine pigment is stable. It was discovered that the sensitivity decreases when crystal transition occurs in the mold, and based on this fact, a dispersion solvent that does not cause crystal transition is added and dispersed in the binder resin, and not only the fraction of the time but also the conductive support. Since it reliably prevents crystal transition to a stable form during coating and dry assimilation, it is possible to form a photosensitive layer by dispersing it in a binder resin without crystal transition to a stable form.
By breaking away from the conventional idea that a stable type is better and carefully selecting a dispersing solvent, a photoreceptor with extremely high sensitivity was obtained.

Moreover, since the above-mentioned phthalocyanine pigment is crushed and dispersed with a monomer before being dispersed in the binder resin, the surface of the pigment powder particles is coated with the monomer, and the particle surface is protected even after the photoreceptor is formed. , it has excellent aging and repeatability characteristics, and also has better wetting with the binder resin than when the solvent is adsorbed to the powder particles, so it can be used as a coating liquid.
It was possible to obtain a photoreceptor with finer particles and good fractional stability, and as a whole, a photoreceptor with excellent aging and repetition characteristics and higher sensitivity was obtained.

Phthalocyanine in the present invention includes metal-free phthalocyanine, copper, nickel, cobalt, zinc, tin, iron,
Natrif A1 is a metal 7-lycyanine such as lithium, calcium, magnesium, or a mixture thereof.

In the phthalocyanine derivatives and shite of the present invention, 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.
7-talonitrile, 7-talic acid, 7-thalic anhydride as raw materials for phthalocyanine, phthalonitrile substituted with the above substituents as phthalimide, 7-thalic acid, phthalic anhydride, 7
By using talimide, if some of them are used in combination, the following results can be obtained.

Inorganic acids that can form salts with the phthalocyanine used in the present invention include sulfuric acid, or-IJ acid, birophosphoric acid,
Chlorosulfonic acid, hydrochloric acid, hydroiodic acid, hydrofluoric acid, hydrobromic acid, etc. are used. These inorganic acids are those used in conventionally known methods such as phthalocyanine acid pasting method and acinto slurry method. Moreover, as a 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), Decompose the inorganic acid salt of phthalocyanine with a basic substance such as ammonia gas,
There are methods to precipitate 7-talocyanine.

Solp acetate: manufactured by Nagase Sangyo Co., Ltd.), ester solvents such as butyl acetate, alcohol solvents such as n-butanol, methanol, ethanol, n-propertool, n-pentanol, or ether solvents. Ethylene glycol monoethyl ether (ethyl cellosol), ethylene glycol monoethyl ether, which is a part of the above, or a mixed solvent thereof can be used.

However, when the above-mentioned ethylene glycol monoethyl ether acetate is used, if it is stored as a coating liquid, the Fi will gradually change, but there is a risk that crystal transition will progress, so it should not be applied to the conductive support early after the coating liquid is prepared. need to be applied. On the other hand, with the Delcor solvent, crystal transition does not occur even if the coating solution is stored for more than one month, and therefore, it is preferable to use an alcohol solvent as the fractional solvent.

As the binder resin, general binder resins such as electrically insulating thermoplastic resins, thermosetting resins, photoconductive resins such as PVK, and photocuring resins are used. Possible and suitable specific examples include saturated polyester resin, polyamide resin, acrylic resin, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate copolymer, polycarbonate, chlorinated vinegar, acid vinyl A polymer, Thermoplastic binder resins such as cellulose ester and polyamide, epoxy resins, flexible resins, silicone resins, phenolic resins, melamine resins,
A thermosetting binder resin such as a thermosetting acrylic resin, an acrylic resin, or a xylene resin, preferably a thermosetting acrylic resin.

In addition, as monomers, vinyl monomers (e.g., vinyl acetate monomer), acrylic monomers (e.g., methyl methacrylate, 2-methacrylate and droxyethyl), etc. can be used (however, aromatic monomers such as styrene monomers, etc.) can be used. In particular, if a binder resin monomer is used, the compatibility during dispersion will be improved and a stable coating liquid with higher sensitivity can be obtained. When a binder resin is selected, it is preferable to use a combination of the selected resin. Further, the amount of 7-mer used is not less than the oil absorption amount of the phthalocyanine pigment according to the present invention, and can be diluted until the solid ratio of the phthalocyanine pigment becomes 20 parts. If the amount is less than the above range, pulverization and dispersion will be insufficient.
On the other hand, if the amount exceeds the above range, it will adversely affect the viscosity during spray coating and the characteristics of the photoreceptor. Examples, comparative examples, and experimental results will be described below.

Example 1 Parts by weight of copper phthalocyaninda θ and parts by weight of copper phthalocyanin O,j are dissolved in parts by weight of 2/th concentrated sulfuric acid ◆soo while thoroughly stirring and mixing, and then the solution is dissolved in 500 parts by weight of water.
0 parts by weight to precipitate a composition of copper 7-lycyanine and tetranitrocopper phthalocyanine, followed by filtering, washing with water, and drying under reduced pressure in a vacuum chamber. The thus obtained amorphous unstable copper phthalocyanine (toy) is pre-pulverized and dispersed in a ball mill for 1 day using 2-hydroxyethyl methacrylate (lay), which is a type of functional monomer for acrylic resin, and then heat-curable. acrylic resin(
Acridic A405: Dainippon Ink Co., Ltd.) (
2J, iy") and a mixed solvent (ethyl cello solder (Wako Pure Chemical Industries, Ltd.: 1st class): n-butanol = 1: l) (,7!, 2f') as a fractional solvent. After adding and dispersing it for several days to create a coating solution and adjusting its viscosity, the grade was applied to a conductive support and dried and solidified at about 760°C to produce a photoreceptor with a dry film thickness of 70μ. .

Comparative Example A photoreceptor was prepared in the same manner as in Example 1 except that the above mixed solvent (joy) was used in place of the above meta>2-hydroxyethyl lylate (JOp). Regarding the above two types of photoreceptors, initial surface potential (Vo), half-decrease exposure amount (E'/), dark decay rate (D
DRI) and the change in surface potential (ΔVo) after copying 20 times as a repetitive characteristic, the results shown in the following table were obtained.

From the above results in Table 1, it is clear that the photoreceptor of Example 1 has significantly improved repeatability while having the same sensitivity as the photoreceptor of Comparative Example.

Example 2 A photoreceptor was produced in the same manner as in Example 1 except that polyethylene glycol monomethacrylate (PE90: manufactured by NOF Corporation) was used instead of 2-hydroxyethyl methacrylate.

Example 3 Polypropylene glycol monomethacrylate (P P 10
A photoreceptor was produced in the same manner as in Example 1 except that 00: Nippon Oil & Fats Co., Ltd.) was used.

The electrostatic properties and cyclic properties of each of the photoreceptors of Examples 2 and 3 were measured, and the results shown in the following table were obtained.

The above results in Table 2 show that compared to Comparative Example, the sensitivity is particularly poor in Example 3, but since the dark decay rate and repetition characteristics are excellent, Comparative Example 3 is suitable as a copy image. Better results can be obtained over a longer period of time.

From the above results, it can be seen that as the main chain, sides, and chains become longer, the electrostatic properties and repeatability properties deteriorate accordingly.

Example 4 A photoreceptor was prepared in the same manner as in Example 1 except that y% of the NQx-resistant agent was added to Bakugou in a system containing only methacrylic e-2 hydroxyethyl and a mixed solvent.

When the electrostatic properties and cyclic properties of the photoreceptor of Example 4 were measured, the results shown in the following table were obtained. still,
It indicates the value of the total current flowing through the charger.

Third, the characteristics of the photoreceptors of Examples 1 and 4 after copying 1000 times were measured, and the results shown in the following table were obtained.

From these results in Table 4, it is clear that adding the NQx resistant agent can improve the repeatability, although the sensitivity decreases to some extent.

As a reference example, the mixed solvent (7j,
, 2y) to 2-hydroxyethyl methacrylate (7i,
xy), a photoreceptor was produced in the same manner as in Example 1,
The aging characteristics of the photoreceptor were measured, and the results shown in the following table were obtained.

Table 5, page 1 continued 0 Inventor Mitsutoshi Sakamoto Osaka Kokusai Building Minolta Camera Co., Ltd. 2-30 Azuchi-cho, Higashi-ku, Osaka 0 Inventor Hideaki Ueda Osaka Kokusai Building Minolta 2-30 Azuchi-cho, Higashi-ku, Osaka Power, Mera Co., Ltd. ■Applicant: Toyo Ink Manufacturing Co., Ltd. 2-3-13 Kyobashi, Chuo-ku, Tokyo

Claims (1)

[Claims] ■ Phthalocyanine and phthalocyanine in which the benzene nucleus of the phthalocyanine molecule is substituted with at least seven types of electron-withdrawing groups selected from nitro groups, cyano groups, norogen atoms, sulfone groups, and carboxyl groups: / After mixing the derivative with an inorganic acid that can form a salt with phthalocyanine, the phthalocyanine pigment obtained by precipitation with water or a basic substance is added without binding and dispersed in a binder resin. A method for producing an electrophotographic photoreceptor by coating it on a conductive support and drying and solidifying it. (2) The manufacturing method according to claim 0, wherein the dispersion solvent is an alcohol solvent. (2) The manufacturing method according to claim 0 or 0, wherein the monomer is a monomer of a dispersed binder resin.