JPH02124576A - Production of electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To form a charge transfer layer stably by dipping a base body for an electrophotographic sensitive body in a coating soln. for forming a charge transfer layer having a specified compsn. and specified characteristics and coating the soln. on the base body. CONSTITUTION:A coating soln. consisting of polycarbonate Z resin having 19,000-70,000mol.wt. and a charge transfer material expressed by the formula I is used, wherein a proportion of the charge transfer material to the polycarbonate Z resin is 30:70-60:40, and a viscosity of the coating soln. is regulated to 200-2,000cp. Suitable solvents to be used for the prepn. of the coating soln. are aromatic hydrocarbons such as benzene, toluene, xylene, chlorobenzene, ketones such as acetone, 2-butanone, halogenated aliphatic hydrocarbons such as methylene chloride, chloroform, ethylene chloride, ethers such as tetrahydrofuran, dioxane, ethylene glycol, diethyl ether, etc. Thus, a uniform charge transfer layer is formed stably.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing a laminated functionally separated electrophotographic photoreceptor.

BACKGROUND OF THE INVENTION Recently, electrophotographic photoreceptors having a standby photoconductive layer on a conductive support, in particular a charge generation layer in which the photosensitive layer absorbs visible light and generates charges, and a charge transport layer to transport the charges, have been developed. Various types of laminated photoreceptors with separate functions have been proposed.

For example, the charge generation layer can be formed by applying a coating solution obtained by adding a charge generation agent to a solution in which a binder resin is dissolved in an appropriate solvent using a dip coating device so that the film thickness is approximately 0.05 to 5 μm. formed by

Examples of the charge generating agent include polycyclic quinone pigments, perylene pigments, indigo pigments, hisbenzimidazole pigments,
Known pigments such as ginacridone pigments, phthalocyanine pigments, monoazo pigments, disazo pigments and other polyazo pigments can be used. Examples of the binder resin include polycarbonate, polystyrene, polyester, polyvinyl butyral, methacrylic acid ester polymer or copolymer, vinyl acetate polymer or copolymer, cellulose ester or ether, polybutadiene, polyurethane, epoxy resin, etc. , publicly known ones can be used.

On the other hand, the charge transport layer is formed by applying a coating solution obtained by dissolving the charge transport agent or the binder resin in a suitable solvent to a film thickness of approximately 5 to 50 mm using a dip coating device. It is formed.

In this case, as the charge transport agent, amine compounds, hydrazone compounds, pyrazoline compounds, oxazole compounds, oxadiazole compounds, sudirbene compounds, carbazole compounds, etc. are used. In addition, if the charge transport agent itself does not have film-forming properties, a suitable binder resin such as polycarbonate, polyarylate, polyester, polystyrene, styrene-acrylonitrile copolymer, polysulfone, polymethacrylic acid Esters, styrene-methacrylic acid ester copolymers, etc. are used.

Among these charge transport agents and calculus resins, the following formula (I> (wherein, R represents an alkyl group, and R2 and R3 are each a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, an alkoxycarbonyl group, or a substituted amino Indicates the group.

) and a polycarbonate resin, particularly a polycarbonate resin [poly(4,4'-cyclohexylidene diphenylene carbonate)],
Since they are excellent in electrophotographic properties such as film formability, potential retention, and sensitivity, various electrophotographic photoreceptors having charge transport layers using such combinations have been proposed. (For example, Japanese Unexamined Patent Publication No. 62-242950) Problems to be Solved by the Invention By the way, regarding a functionally separated electrophotographic photoreceptor having a charge transport layer using the above combination, the formation of the charge transport layer is When a coating solution containing a polycarbonate resin and a charge transport agent represented by the above formula (I>) dissolved in a solvent is applied by dip coating, the formed charge transport layer is
It often occurred that the coating film was not uniform or that the film formability and mechanical strength of the coating film were poor. In addition, the produced electrophotographic photoreceptors often have poor sensitivity or low chargeability, resulting in poor cycle characteristics. Couldn't get it to work.

The present invention has been made in view of the above-mentioned circumstances in the prior art.

Therefore, an object of the present invention is to provide a method for producing an electrophotographic photoreceptor that can always stably obtain an electrophotographic photoreceptor having good electrophotographic properties.

Means for Solving the Problems As a result of study, the present inventors have found that if the coating liquid for forming a charge transport layer used in dip coating satisfies conditions within a specific range, a uniform charge transport layer can be formed. The present inventors have discovered that it is possible to obtain an electrophotographic photoreceptor having excellent electrophotographic properties as a result, and have completed the present invention.

The present invention comprises a step of forming a charge generation layer and a step of forming a charge transport layer, and the step of forming the charge transport layer comprises:
In a method for producing an electrophotographic photoreceptor, which comprises dip coating a coating solution in which a polycarbonate resin and a charge transport agent represented by the above formula (I) are dissolved in a solvent, the polycarbonate resin has a molecular weight of 19,000 to 70,000.
The charge transport agent and the polycarbonate l
It is characterized by using a coating liquid having a mixing ratio with the resin in the range of 30:70 to 60:40 and a viscosity adjusted to 200 to 2000 CII.

The present invention will be explained in detail below.

The electrophotographic photoreceptor produced by the method of the present invention has a charge generation layer and a charge transport layer sequentially provided on a conductive support. A barrier layer is provided between the charge generation layer and the conductive support.
An intermediate layer such as an undercoat layer may be provided.

The charge generation layer is made by dispersing a charge generation agent in a binder resin as described above, and a coating solution in which the charge generation layer is dispersed in an organic solvent solution of the binder resin is coated with a film thickness o, oos. It is formed by coating so that the thickness is in the range of ~5 μm.

As the charge generating agent, known ones can be used, such as polycyclic quinone pigments, perylene pigments, indigo pigments, hisbenzimidazole pigments, quinacridone pigments, phthalocyanine pigments, monoazo pigments, disazo pigments, and other polyazo pigments. Examples of the adhesive resin include polycarbonate, polystyrene, polyester, polyvinyl butyral, methacrylic acid ester polymer or copolymer, vinyl acetate polymer or copolymer, cellulose ester or ether, polybutadiene, polyurethane, epoxy resin, etc. can be used.

The charge transport layer is made of polycarbonate resin and a charge transport agent represented by the formula (I) as described above, and has a film thickness of 5.
It is formed to have a thickness of about 50 μm.

In the present invention, the charge transport layer is formed by dip coating while circulating a coating solution in which a polycarbonate resin and a charge transport agent represented by the following formula (1) are dissolved in a solvent in a dip coating device. .

Examples of solvents used in the coating solution include benzene,
1 - Aromatic hydrocarbons such as toluene, xylene, and chlorobenzene, ketones such as acetone and 2-butanone, halogenated aliphatic hydrocarbons such as methylene chloride, chloroform, and ethylene chloride, tetrahydrofuran, dioxane,
Examples include ethers such as ethylene glycol and diethyl ether.

In the present invention, it is necessary that the polycarbonate resin added to the coating liquid has a molecular weight in the range of 19,000 to 70,000. When a coating solution within this range is used, gelation of the coating solution does not occur even after three months have passed, and the coating solution can be used suitably. If the molecular weight is lower than 19,000, the film formability and mechanical strength of the coating film will be poor, and if the formed photoreceptor is used repeatedly, the coating film will be scratched, resulting in the formation of an image that can be scratched. It becomes like this. Moreover, when the molecular weight is higher than 70,000, the viscosity of the coating liquid becomes too high, causing a problem of gelation.

In the present invention, the mixing ratio (weight) of the charge transport agent and polycarbonate resin in the coating solution is 30:70.
It is necessary to be in the range of ~60:40.

If this ratio is less than 30:70, the resulting electrophotographic photoreceptor will have low sensitivity and will be unsuitable for practical use.

On the other hand, when the ratio exceeds 60:40, the amount of the charge transport agent is too large relative to the polycarbonate resin, resulting in a decrease in strength as a coating film, a decrease in chargeability, and a deterioration in cycle characteristics.

Generally speaking, in the present invention, the coating liquid has a viscosity of 200 to 200
It is necessary that it is adjusted to 0cρ. If the coating liquid has a viscosity of 200 cp and is not vortexed, the pulling speed must be very high in order to obtain a predetermined film thickness, resulting in a large drop in film thickness, making it unusable.

Moreover, when it is larger than 2000 cp, the fluidity of the coating liquid is poor, making it difficult to circulate the coating liquid and making it impossible to perform dip coating smoothly.

Example The present invention will be explained below with reference to Examples.

Example 1 8 nylon resin (trade name Laccamite, Dainippon Ink ■
Prepare a methanol/butanol mixed solution of
It was applied to the surface of 4#φX310#). After air drying for 5 minutes, it was placed in a dryer, heated to 100° C., and dried for 10 minutes. This results in a film thickness of 1. A barrier layer of Opm was formed.

Polyvinyl butyral resin (product name BH1, Tanksui Chemical ■
1 part (by weight, same hereinafter) of cyclohexanone 19
It was dissolved in parts. 8 parts of dibromanthammyluron pigment (C, I, Pigment Red 168) were mixed into this solution.

Next, dispersion was performed using a sand mill using 1 mφ glass beads as a dispersion medium. A coating solution for forming a charge generation layer having a solid content concentration of approximately 10% was prepared by roughly adding cyclohexanone to the dispersion. This coating solution was coated onto the barrier layer by dip coating to achieve a dry film thickness of 0. It was applied so that it became .8jIM.

On the other hand, N,N'-diphenyl-N,N'-bis(3
-methylphenyl) -[1,1'-biphenyl]-4
, 3 parts of 4'-diamine as a charge transport agent, molecular weight 190
00 polycarbonate l resin was dissolved in 35 parts of monochlorobenzene. The resulting coating liquid for forming a charge transport layer had a viscosity of 200 cp. This coating liquid,
Supplied to a dip coating device, at a coating speed of 15 cm/min,
It was coated on the charge generation layer and dried at 100° C. for 1 hour to form a charge transport layer with a thickness of 201 JA, thereby obtaining an electrophotographic photoreceptor.

Comparative Example 1 An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that the charge transport layer was formed as described below.

2.5 parts of N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[1,1'-biphenyl]-4,4'-diamine was used as a charge transport agent, and polycarbonate with a molecular weight of 19,000 was used. It was dissolved together with resins 7 and 5 in 35 parts of monochlorobenzene. The obtained coating liquid for forming a charge transport layer (viscosity 250 cp) was supplied to a dip coating device,
It was coated on the charge generation layer at a coating speed of 10 cm/min and dried at 100°C for 1 hour to form a charge transport layer with a film thickness of 20cm/min.

Comparative Example 2 An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that the charge transport layer was formed as described below.

Polycarbonate l resin 7 with a molecular weight of 17,000 using 3 parts of N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[1,1'-biphenyl]-4,4'-diamine as a charge transport agent. It was also dissolved in 25 parts of monochlorobenzene. The obtained coating liquid for forming a charge transport layer (viscosity: 230 cp) was supplied to a dip coating device, and the coating speed was set to 9.
cm/...in on the charge generation layer and dried at 100° C. for 1 hour to form a charge transport layer with a thickness of 20 μm.

Comparative Example 3 An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that the charge transport layer was formed as described below.

Polycarbonate l resin 7 with a molecular weight of 19,000 using 3 parts of N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[1,1'-biphenyl]-4,4'-diamine as a charge transport agent. In addition, monochlorobenzene 45
It was dissolved in parts. The resulting coating solution for forming a charge transport layer is
The viscosity was 120 cp. This coating solution was supplied to a dip coating device and coated on the charge generation layer at a coating speed of 25 cm/min to form a charge transport layer with a dry film thickness of 20 cm. There was a 6 instant difference in thickness.

Example 2 An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that the charge transport layer was formed as described below.

3.5 parts of N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[1,1'-biphenyl]-4,4'-diamine as a charge transport agent, and polycarbonate with a molecular weight of 21,000. 30 parts of toluene along with 6.5 parts of resin
It was dissolved in parts. The resulting coating solution for forming a charge transport layer (viscosity: 300 cp) was supplied to a dip coating device and coated on the charge generation layer at a coating speed of 7 cm/min.
It was dried for 1 hour at 'C to form a charge transport layer with a thickness of 20 cm.

Example 3 An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that the charge transport layer was formed as described below.

3,3'-dimedyruN,N'-bis(4-
ethyl phenyl) -N,N'-bis(4-methylphenyl)-[1,1"-hyphenyl]-4.4'-diamine as a charge transport agent, together with 6.5 parts of polycarbonate resin having a molecular weight of 21,000. , monochlorobenzene 26
It was dissolved in parts. The resulting coating solution for forming a charge transport layer (viscosity: 380 cp) was supplied to a dip coating device, coated on the charge generation layer at a coating speed of 7 cm/min, and heated at 100°C.
This was dried for 1 hour to form a charge transport layer with a thickness of 20 pm.

Example 4 An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that the charge transport layer was formed as described below.

6 parts of NN'-diphenyl-N,N'-bis(3-methylphenyl)-[1,1'-hyphenyl]-4,4'-diamine as a charge transport agent, together with 4 parts of polycarbonate resin having a molecular weight of 70,000. , monochlorobenzene 40
It was dissolved in parts. The resulting coating solution for forming a charge transport layer (viscosity: 2000 Cp) was supplied to a dip coating device and coated on the charge generation layer at a coating speed of 3 cm/min.
It was dried for 1 hour at 0.degree. C. to form a charge transport layer with a thickness of 20 mm.

This coating liquid was put into a circulation machine (diaphragm pump: 5-pole filter) and circulated, but no clogging occurred even after 3 months.

Comparative Example 4 An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that the charge transport layer was formed as described below.

7 parts of N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[1,1'-biphenyl]-4,4'-diamine as a charge transport agent, and 3 parts of polycarbonate resin having a molecular weight of 70,000. In addition, monochlorobenzene 38
It was dissolved in parts. The resulting coating solution for forming a charge transport layer (viscosity t4oocp>) was supplied to a dip coating device and coated on the charge generation layer at a coating speed of 3 cm/min.
C for 1 hour to form a charge transport layer having a thickness of 20 IIn.

Comparative Example 5 Polycarbonate with a molecular weight of 70,000 using 6 parts of N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[1,1'-biphenyl]-4,4'-diamine as a charge transport agent l 4 parts of resin along with 3 parts of monochlorobenzene
It was dissolved in 5 parts. The resulting coating liquid for forming a charge transport layer had a viscosity of 2500 cp. This coating liquid is passed through a circulation machine (
When the coating liquid was put into a diaphragm pump (5 μm pole filter), the fluidity of the coating liquid was poor and it was difficult to circulate the coating liquid.

Comparative Example 6 Polycarbonate with a molecular weight of 100,000 using 6 parts of N,N'-diphenyl-N,N'-bis(3-methylphenylfur)-11,1'-biphenyl]-4,4'-diamine as a charge transport agent It was dissolved in 40 parts of monochlorobenzene together with 4 parts of resin. When the resulting coating solution for forming a charge transport layer was allowed to stand for one week, it gelled and could no longer be used as a coating solution.

The electrophotographic photoreceptors obtained in the above Examples and Comparative Examples were charged with a scorotron and then charged with a 7er
It was exposed to light using an o/cffl halogen lamp, and the surface potential VD of the dark area and the surface potential V[ of the exposed area were measured. io, oo using these electrophotographic photoreceptors.

Surface potentials VD and VL after repeating the copy operation
was measured in the same manner. In addition, the state of the coating film surface of the electrophotographic photoreceptor after 10,000 copying operations was visually observed. The results are shown in Table 1.

Effects of the Invention In the present invention, dip coating is performed using a coating solution for forming a charge transport layer having the composition and properties as described above, so the coating solution is easily circulated during dip coating, and gelation is prevented. The charge transport layer can be stably formed without causing any problems.

Further, the charge transport layer formed has a predetermined uniform thickness, so that the electrophotographic photoreceptor obtained by the present invention has sufficient sensitivity and cycle characteristics.

Patent applicant Fuji Xerox Co., Ltd. Agent
Patent attorney Tsuyoshi Horabe

Claims (1)

[Claims] (1) It comprises a step of forming a charge generation layer and a step of forming a charge transport layer, and the step of forming the charge transport layer consists of polycarbonate Z resin and a charge transport agent represented by the following formula (I) in a solvent. In a method for manufacturing a functionally separated electrophotographic photoreceptor, which comprises applying a dissolved coating liquid by dip coating,
As polycarbonate Z resin, molecular weight 19,000-7
0000, the mixing ratio of the charge transport agent and the polycarbonate Z resin is in the range of 30:70 to 60:40, and the viscosity is adjusted to 200 to 2000 cp. A method for manufacturing a functionally separated electrophotographic photoreceptor, characterized by: ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R_1 represents an alkyl group, R_2 and R_3
each represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, an alkoxycarbonyl group or a substituted amino group. )