JPS60216354A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve sensitivity, charging characteristics, moisture resistance, levelling characteristics, etc. of an electrophotographic sensitive body contg. a photosensitive layer formed by dispersing photoconductive particles in a binder resin by incorporating a coupling agent comprising an Al compd. CONSTITUTION:Wettability and dispersibility of photoconductive particles (e.g. copper phthalocyanine, ZnO) with/in a binder resin (e.g. polystyrene, polypropylene) are improved by mixing 100pts.wt. said photoconductive particles with ca. 0.01-20pts.wt. coupling agent comprising an Al compd. expressed by the formula (wherein R1, R2, and R3 are 1-6C alkyl; R4 is 1-24C alkyl or alkenyl) so as to contact both components intimately with each other. Then, the binder resin and a solvent are admixed, and an obtd. photoconductive coating material is coated on an electroconductive substrate to form the photosensitive layer by drying. The target electrophotographic photosensitive body is thus prepd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to electrophotographic photoreceptors, particularly photoreceptors containing an aluminum-based coupling agent, and electrophotographic photoreceptors containing photoconductive particles, a binder, and an aluminum-based coupling agent. The present invention relates to photographic photoreceptor inks and photoconductive particles treated with aluminum-based coupling agents.

2. Description of the Related Art In general, the quality of images produced by electrophotographic apparatuses is mostly determined by the characteristics of the photoreceptor, and the characteristics of the photoreceptor are the most important factor in electrophotography. In order to improve the properties of the above types of photoreceptors, it goes without saying that the properties of the photoconductive particles themselves, the properties of the binder themselves, etc. are important factors. Even if a binder is selected, the properties will not only be significantly influenced by the adsorption state of the photoconductive particles and the binder before dispersing the photoconductive powder in the binder, but also the moisture resistance ratio. The charging characteristics, charge mobility, sensitivity, etc. are greatly influenced by the combination of the two and the composition r.

A method using a silane coupling agent is known as a method for improving the moisture resistance of electrophotographic photoreceptors. However, in the method using a silane coupling agent, the silane coupling agent itself is positively or negatively charged, so that a positively charged photoreceptor such as copper phthalocyanine may have reduced sensitivity or poor charge retention ability. Furthermore, the adhesion of the photosensitive layer onto the photoreceptor substrate may be adversely affected.

OBJECTS OF THE INVENTION The present invention provides a photoreceptor that has excellent electrophotographic properties such as charging properties and sensitivity, as well as excellent moisture resistance and leveling properties.
Another object of the present invention is to provide an ink for a photoreceptor that has excellent adhesiveness to a substrate.

Structure of the Invention The present invention provides an electrophotographic photoreceptor comprising a photosensitive layer formed by dispersing photoconductive particles in a binder resin, characterized in that the photosensitive layer contains an aluminum-based coupling agent. Regarding.

The photoconductive particles used in the present invention may be any organic photoconductive particles such as zinc oxide, lightning pigments, perylene pigments, and phthalocyanine pigments. Moreover, it is not limited to these. Particularly favorable results are obtained when using phthalocyanine pigments.

As an aluminum-based coupling agent, the formula: [wherein,
A compound represented by k□ R2 and 3 represent an alkyl group having 1 to 6 carbon atoms, and 4 represents an alkyl or alkenyl group having 1 to 24 carbon atoms is used.

ko, R2 and ni3 may have side chains, preferably R□ and R2 are isopropyl groups and R3 is a methyl group. R4 may have a side chain and preferably has 8 to 24 carbon atoms.

Although the aluminum-based coupling agent may be used in combination with the binder resin, it is preferably used as a surface treatment agent for the surface of the photoconductive particles. This gives the surface of the agent photoconductive particles a strong affinity with the binder resin.

Light conductivity using an aluminum coupling agent is carried out by mixing a light conductivity laminium pulling agent and bringing them into sufficient contact.

The amount of the aluminum coupling agent used is 0.01 to 20 parts by weight, more preferably 0.1 to 10 parts by weight, per 100 parts by weight of the photoconductive particles.

As the binder, any resin conventionally used as a binder for photoreceptors such as polystyrene, polyethylene, polypropylene, vinyl resin, acrylic resin, polycarbonate, polyurethane resin, and copolymers of these monomers can be used alone. Or they can be used in combination. Further, any sensitizer, dispersant, leveling agent, etc. can be used in combination.

The weight ratio of photoconductive particles and binder is from 3:1 to 1:
10, especially 2:1 to 2:8.

Effects of the Invention In the present invention, the action of the aluminum-based coupling agent improves the wettability between the photoconductive particles and the binder, and also improves the dispersibility, resulting in excellent electrophotographic properties, moisture resistance, and durability. In addition to providing excellent image quality. It also has the advantage of good manufacturing reproducibility. In addition, even if an aluminum coupling agent is added together with photoconductive particles and a binder during dispersion, it will work as a dispersant, exhibit good electrophotographic properties, and also serve as a leveling agent. , surface smoothness and abrasion resistance are improved.

Example 1 173 parts by weight of cadmium carbonate was added to an aqueous solution containing 0.68 parts by weight of cupric chloride, and hydrogen sulfide was blown into the solution.
(Cu)·nCdω3 is precipitated. This precipitate was filtered, washed with water, dried, pulverized, and calcined at 250°C for 15 hours to obtain CdS(Cu)-nCdC03(0<
n≦4) Photoconductive particles were obtained.

100 parts by weight of the photoconductive particles were added to 170 parts by weight of a toluene solution in which 0.05 parts by weight of AL-M (aluminum coupling agent manufactured by Ajino i Co., Ltd.) was dissolved, and after thorough stirring, the particles were dried. Ta. Cd5(Cu)・n Cd C03 powder 1 treated with this aluminum-based coupling agent
00 parts by weight of Acrydic A405 (Dainippon Ink@
A photoconductive coating material was prepared by sufficiently kneading the mixture with 60 parts by weight of a thermosetting acrylic resin manufactured by ) and 230 parts by weight of toluene in a ball mill to uniformly disperse the mixture. This photoconductive paint was applied onto an aluminum substrate, dried, and then heated and cured at 150° C. for 1 hour to form a 30 μm thick photoconductive layer.

Example 2 CdS(Cu)・nC obtained by the same method as Example 1
100 parts by weight of dCO3 powder was added to 170 parts by weight of a toluene solution in which 2 parts by weight of AL-Mo was dissolved, and after thorough stirring, it was dried. Cd5(Cu)・n Cd COa powder 10 treated with this aluminum coupling agent
0 parts by weight of Acrydic A405 (Dainippon Ink @)
In addition to 45 parts by weight of a curable acrylic resin manufactured by Co., Ltd., 15 parts by weight of a melamine resin manufactured by Super Beckamine J820 (made by Dainippon Ink @) and 230 parts by weight of toluene, a photoconductive paint was prepared by thoroughly kneading the mixture. An electrophotographic photoreceptor was prepared in the same manner as in Example 1.

Comparative Example 1 C d S (Cu ) ・obtained in the same manner as in Example 1
100 parts by weight of n Cd COa particles were added to Acrydic A.
A photoconductive coating material was prepared by kneading the mixture with 60 parts by weight of 4Q5 and 230 parts by weight of toluene, and an electrophotographic photoreceptor was prepared in the same manner as in Example 1.

For each photoreceptor produced in Example 1, Example 2, and Comparative Example 1, the initial electrostatic characteristics and
The electrostatic properties and image quality after humidity control were measured after being left in an atmosphere at a temperature of 30° C. and a relative temperature of 85% for 72 hours.

The results are shown in Table-1. The primary charging voltage applied to the copying machine is -5.5 KV, and E is the exposure amount until the initial charging voltage (vo) drops to 200 cm.

Table 1 Example 3 After adding 40 parts by weight of ε-type copper phthalocyanine (Toyo Ink@) to 5 ornl of an ethanol solution containing 0.4 parts by weight of an aluminum-based coupling agent AL-M, and stirring and mixing thoroughly. , dried, and to this was added 0.4 parts by weight of trinitrofluorenone, 30 parts by weight of polyester polyol urethane (a)), 30 parts by weight of hexamethylene diisocyanate (Desmodur N-75, manufactured by Nippon Polyurethane Co., Ltd.) and Cellosolve Acetate 235.
parts by weight were added and sufficiently kneaded in a magnetic ball mill at room temperature for 48 hours to prepare a photoconductive coating, which was coated on an aluminum substrate, dried and then heated at 150°C for 1 hour to cure to form a 10 μm thick coating. A photoconductive layer was formed.

Example 4 40 parts by weight of ε-type copper phthalocyanine was added to aluminum coupling agent AL-Mo. 2 parts by weight, 0.6 parts by weight of tetracyanoethylene, 48 parts by weight of thermosetting acrylic resin (Acridic A405; manufactured by Dainippon Ink Co., Ltd.), melamine resin (Super Beckamine J820: manufactured by Dainippon Ink @) 12 parts by weight and Cellosolve Acetate 235
Example 3
An electrophotographic photoreceptor was prepared in the same manner as described above.

Example 5 50 parts by weight of copper phthalocyanine and 1 part by weight of mononitro copper phthalocyanine were dissolved in 300 parts by weight of 98% concentrated sulfuric acid with thorough stirring. After precipitating the dissolved liquid, filtration,
It was washed with water and dried at 120°C under reduced pressure. Add 15 parts by weight of this composition to 0.1 part of the aluminum coupling agent AL-M.
In addition to 50 parts by weight of an ethanol solution, the mixture was thoroughly stirred and mixed, and then dried. To this, 36 parts by weight of acrylic polyol (manufactured by Sotoen Yakuhin@) and 5 parts by weight of epoxy resin (manufactured by Shell Kagaku@)) were added. and methyl ethyl ketone:cellosolve acetate) (1:1) mixed solvent were added thereto and kneaded to prepare a photoconductive paint, and an electrophotographic photoreceptor was prepared in the same manner as in Example 3.

Example 6 0.2 parts by weight of an aluminum coupling agent AL-M was added to 15 parts by weight of the composition obtained in Example 5, and 1 part by weight of P-diethylaminobenzaldehyde diphenylhydrazone was added.
5 parts by weight, thermosetting acrylic resin (Dainippon Ink Co., Ltd.)
) 32 parts by weight and melamine resin (Dainippon Ink@)
A photoconductive paint was prepared by adding 8 parts by weight of methyl ethyl ketone: cellosolve acetate (1:1) mixed solvent, and an electrophotographic photoreceptor was prepared in the same manner as in Example 3.

Comparative Example 2 40 parts by weight of ε-type copper phthalocyanine, 0.4 parts by weight of trinitrofluorenone, 30 parts by weight of polyester polyol (Desmophene $800: manufactured by Nippon Polyurethane Co., Ltd.),
Hexamethylene diisocyanate (desmodur N-
75; manufactured by Nippon Polyurethane Co., Ltd.) and 235 parts by weight of cellosolve acetate were kneaded to prepare a photoconductive paint, and an electrophotographic photoreceptor was prepared in the same manner as in Example 3.

Comparative Example 3 15 parts by weight of the composition obtained in Example 5, 15 parts by weight of P-diethylaminobenzaldehyde diphenylhydrazone, 32 parts by weight of thermosetting acrylic resin (manufactured by Dainippon Ink Co., Ltd.), and melamine resin (Dainippon Ink @ ), and added 8 parts by weight of methyl ethyl ketone: cellosolve acetate (
A photoconductive coating material was prepared by kneading the mixture with 100 parts by weight of a 1:1) mixed solvent, and an electrophotographic photoreceptor was prepared in the same manner as in Example 3.

Comparative Example 4 15 parts by weight of the composition obtained in Example 5 was added to 50 m/ml of an ethanol solution containing 0.2 parts by weight of a silane coupling agent (KBM5Q3: manufactured by Shin-Etsu Chemical Co., Ltd.), and the mixture was thoroughly stirred and mixed. , dried, and to this were added 15 parts by weight of P-diethylaminobenzaldehyde diphenylhydrazone, 32 parts by weight of thermosetting acrylic resin (manufactured by Dainippon Ink@) and 8 parts by weight of melamine resin, and methyl ethyl ketone: cellosolve acetate (1:1) was added. A photoconductive coating material was prepared by kneading it with 100 parts by weight of a mixed solvent, and an electrophotographic photoreceptor was prepared in the same manner as in Example 3.

The above photoreceptor was incorporated into a commercially available Carlson type electrophotographic copying machine, and the electrostatic characteristics before and after humidity conditioning treatment and the image quality after humidity conditioning were investigated. The results are shown in Table-2. In Table 2, Vo is the photoreceptor surface potential immediately after applying a DC voltage of +7.5 KV, and E1/2 is the initial surface potential (■). This is the amount of exposure required to reach a potential of 1/2 of that of . Humidity control treatment is 30℃
The test was carried out by being left in an atmosphere with a relative humidity of 85% for 72 hours.

Table 2 As is clear from Tables 1 and 2, the electrophotographic photoreceptor according to the present invention has good electrophotographic characteristics such as charging characteristics and sensitivity, and even after humidity conditioning, the charging characteristics and sensitivity are almost the same as those at the initial stage. In addition, the image quality is good and the repeatability is also good.

Furthermore, since the wettability with the photoconductive particles is improved, the dispersibility is improved, good image quality can be obtained, and the manufacturing stability is also improved.

Example, 7 Polyester resin e (Iron 200, manufactured by Toyobo @) was added to a dispersion obtained by adding 1 part by weight of Diampoule-(C, 1, No, 21180) to 3 parts by weight of THF and dispersing it in a ball mill. A charge generation layer was formed by dissolving 1.5 parts by weight of P-diethylaminobenzaldehyde (diphenylhydrazone) and polycarbonate by coating the coating solution on an aluminum substrate so that the film thickness after drying was 2 μm. (Panlite 1300, manufactured by Teijin Kasei@)) 10 parts by weight and aluminum coupling agent A”L-M
A charge transport layer was formed by coating a coating solution prepared by dissolving 5 parts by weight of □, 0 in 90 parts by weight of 1,2-dichloroethane onto an aluminum substrate so that the film thickness after drying was 20 μm.

The same measurements as in Example 1 were performed on this electrophotographic photoreceptor.

The results are shown in Table-3.

Table-3 As shown in the above values, the sensitivity is good and there is little change even after humidity adjustment.

That is, the effects of the present invention are significant even in the case of a laminated type photoreceptor.

Patent applicant: Minolta Camera Co., Ltd. Representing patent attorney Ao Yamaboshi and 2 others

Claims (1)

[Scope of Claims] 1. An electrophotographic photoreceptor comprising a photoreceptor layer formed by dispersing photoconductive particles in a binder resin, the electrophotographic photoreceptor comprising an aluminum-based coupling agent. 2. The photoreceptor according to item 1, wherein the photoconductive particles are treated with an aluminum-based coupling agent. 3. The photoreceptor according to item 1, wherein the photoconductive particles are a phthalocyanine pigment. 4. The aluminum coupling agent has the formula: [wherein, R□
R2 and ni3 are alkyl groups having 1 to 6 carbon atoms and ni4
represents an alkyl or alkenyl group having 1 to 24 carbon atoms. 5. The photoreceptor according to item 4, wherein R1 and 2 are isopropyl groups, R3 is a methyl group, and 4 is an alkyl or alkenyl group having 8 to 24 carbon atoms.