JPH02203348A - Production of organic photosensitive body - Google Patents

Abstract

PURPOSE:To obtain the org. photosensitive body which obviates the generation of color sepn. and whitening by using a mixed solvent of dioxane/cyclohexanone as a solvent for forming a charge generating layer. CONSTITUTION:A coating liquid (charge generating layer-forming liquid) prepd. by dispersing a phthalocyanine pigment which is a charge generating material and a resin (binder) in the mixed solvent of the dioxane/cyclohexanone is applied on a conductive base body to form the charge generating layer. A coating liquid (charge transfer layer-forming liquid) prepd. by dissolving a charge transfer material and a binder in a suitable solvent is then prepd. and the charge transfer layer is formed by applying this liquid on the charge generating layer, by which the org. photosensitive body for electrophotography of a lamination type is obtd. The org. photosensitive body which obviates the generation of the color sepn. and whitening (brushing) is obtd. in this way.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a method for producing an organic photoreceptor suitable as an electrophotographic photoreceptor, and in particular, to a method for producing an organic photoreceptor that provides a photosensitive layer with excellent sensitivity and strength. It is about the method.

[Prior art and interlayer points]

As an organic photoreceptor, a laminated type photoreceptor is known in which the photosensitive function is separated into a charge generation layer and a charge transfer layer.

For example, polyester resin, which has good adhesion to the substrate, is used as a binder for the charge generation layer of the laminated photoreceptor.

A charge generation layer is formed by dissolving a polyester resin in tetrahydrofuran (THF) and coating a solution prepared by mixing phthalocyanine photoconductive fine powder into the above solution on a tetraelectric substrate.

However, when THF is used as a solvent, since the boiling point of TIIF is low, a one-color separation phenomenon or a whitening phenomenon (brushing) occurs in the obtained charge generation layer.

Therefore, the incident light undergoes diffuse reflection during exposure, reducing the sensitivity of the photosensitive layer. Furthermore, by causing such a phenomenon, the adhesion with the substrate deteriorates, making layer peeling more likely to occur.

[Problem of invention]

An object of the present invention is to provide a method for manufacturing an organic photoreceptor that does not cause the above-mentioned color separation phenomenon and whitening phenomenon observed in conventional charge generation layers.

[Means to solve the problem]

As a result of various studies to solve the above problems, the present inventors have discovered that dioxane/
The inventors have discovered that the above problems can be solved by using a cyclohexanone mixed solvent, and have completed the present invention.

That is, according to the present invention, in a method for manufacturing a layered organic photoreceptor comprising a charge generation layer and a charge transfer layer, the charge generation layer containing phthalocyanine photoconductive fine powder dispersed in a resin, A method for producing an organic photoreceptor is provided, which is characterized in that a mixed solvent of dioxane/cyclohexanone is used as a solvent for forming a charge generation layer.

In the present invention, a mixed solvent of dioxane and cyclohexanone is used as a solvent for forming a charge generation layer made of phthalocyanine photoconductive fine powder dispersed in a resin. When dioxane alone is used as a solvent, the resulting photoreceptor has excellent charging ability and photosensitivity, but has the disadvantage that the adhesion between the substrate and the charge generation layer is somewhat weak. This drawback is overcome by the addition of cyclohexanone. Cyclohexanone partially dissolves phthalocyanine pigments,
Like a surfactant, it works effectively to disperse ultrafine particles, and therefore, by adding cyclohexanone to dioxane, it is possible to produce a photoreceptor with excellent adhesion and excellent charging characteristics. The appropriate amount of cyclohexanone to be used is 3 to 100 parts by weight, preferably 5 to 50 parts by weight, per 100 parts by weight of dioxane. If the amount of cyclohexanone is less than 3 parts by weight, the effects of the present invention will not be sufficiently exhibited.

On the other hand, if cyclohexanone exceeds 100 parts by weight, the photosensitivity will decrease.

The method for manufacturing the organic photoreceptor of the present invention is carried out, for example, as follows.

First, a coating liquid (charge generation layer forming liquid) in which a phthalocyanine pigment, which is a charge generation substance, and a resin (binder) are dispersed in a dioxane/cyclohexanone mixed solvent is applied onto a conductive substrate to form a charge generation layer. do. The thickness of the charge generation layer at this time is 2.0 microns or less, preferably 0.1 to 0.0 microns.
5 microns is appropriate.

Next, mL of a coating liquid (charge transfer layer forming liquid) in which a charge transfer substance and a binder are dissolved in an appropriate solvent is applied onto the charge generation layer to form a charge transfer layer. and a laminated type organic photoreceptor for electrophotography. The thickness of the charge transfer layer at this time is suitably 12 to 20 microns. In this way, a Jej type organic photoreceptor can be obtained.

As the phthalocyanine photoconductive fine powder used in the charge generation layer in the present invention, conventionally known ones can be used. Examples of these include copper phthalocyanine, titanyl phthalocyanine, metal-free phthalocyanine, and the like. Its average particle size is 0.05-0.5 μs, preferably 0.05
~0.1-. Furthermore, as the resin (binder) for adhering such fine powder to the support, any resin can be used as long as it is soluble in the dioxane/cyclohexanone mixed solvent. Examples of such resins include polyester resins, polyvinyl butyral resins, polymethyl methacrylate resins, phenoxy resins, and phenol resins. Examples of the polyester resin include those having a molecular weight of 15,000 to 20,000 obtained by reacting terephthalic acid or isophthalic acid with ethylene glycol. Further, as the polyvinyl butyral resin, one having a molecular weight of about 10,000 to 100,000 is preferably used. The amount of binder resin used is 100% of the phthalocyanine photoconductive fine powder.
The proportion is 60 to 200 parts by weight. The preferred composition of the charge generation layer forming liquid is as follows: 0.5 to 3% by weight of phthalocyanine photoconductive fine powder, preferably 1 to 3% by weight, and 0.5 to 5% by weight of binder resin in the solvent. %,
Preferably it is 1 to 3% by weight.

The charge transfer layer in the present invention can be formed according to a conventionally known method. That is, a coating solution may be prepared by dissolving a charge transfer substance and a binder resin in an organic solvent, and this may be coated on a charge generation layer formed on a support and dried. As the charge transfer substance, a conventionally known substance can be used. Examples of such compounds include pyrazoline compounds (Japanese Patent Application Laid-Open No. 60-225850) and hydrazone compounds (
Special Publication No. 55-42380). In the present invention, it is particularly preferable to use a pyrazoline compound represented by the following general formula (1) and a hydrazone compound represented by the general formula (II).

(In the formula, R1, R2, R3 and R4 represent a lower alkyl group, and X represents an optionally substituted phenyl group) +13 (In the formula, R1 and R2 represent a lower alkyl group, R3, R4,
R5 represents hydrogen or a lower alkyl group) Examples of the binder resin used in the charge transfer layer include polyester resins, polycarbonate resins, acrylic resins, methacrylic resins, and polyurethane resins. The binder resin is preferably used in an amount of 60 to 150 parts by weight based on 100 parts by weight of the charge transfer material. As the charge transfer layer forming solvent, conventionally known solvents such as methylene chloride/cyclohexanone mixed solvent, dichloroethane, tetrahydrofuran, etc. are used.

The support used in the electrophotographic photoreceptor of the present invention may be any material as long as it has conductivity, such as a metal plate such as aluminum or copper, or a plastic sheet treated with conductivity with aluminum, carbon black, tin oxide, etc. .

The photoreceptor of the present invention is applied to devices that utilize a process using a semiconductor laser as a light source, such as an electrophotographic printer.

(Example) The present invention will be explained in detail below using examples.

Example 1 [Charge generation J ~ Formation liquid composition] 5 parts by weight of ε-type copper phthalocyanine The above composition was subjected to superwave dispersion for 1 hour, and the resulting dispersion was used to form a PIMiT film with a thickness of 75 microns on which aluminum was deposited. A charge generation layer having a thickness of 0.3 microns was formed by applying the coating using a wire parser and drying it.

[Charge transfer layer forming liquid composition]

The above composition was stirred and dissolved using a stirrer. This liquid was applied onto the charge generation layer using a spinner and dried to form a charge transfer layer. The film thickness at this time was 18 microns.

The laminated organic photoreceptor thus obtained was statically subjected to corona discharge at 16 kV using an electrostatic charging tester (Kawaguchi Electric, Model EPA-8100). What is the surface potential at this time? l+q constant (initial potential V
. ). Furthermore, the surface potential of this photoreceptor after being left in the dark for 5 seconds was determined as dl (dark decay potential Vs). Then,
Light is irradiated from a tungsten lamp at a surface illuminance of 10 lux, and the surface potential is 1/2. or by measuring the time until the light sensitivity decreases to 115.
Iil! I decided. Further, in order to measure the spectral sensitivity, 1 μ11/aJ light separated by a monochromator was irradiated, and the half i1F light energy sensitivity (μJ/cA) was determined. The results are shown in Table 1.

Example 2 A photoreceptor was manufactured in exactly the same manner as in Example 1 except that X-type metal-free phthalocyanine was used instead of ε-type copper phthalocyanine, and the electrophotographic properties were measured in the same manner as in Example 1. . The measurement results are also listed in Table 1.

Example 3 A photoreceptor was manufactured in exactly the same manner as in Example 1 except that titanyl phthalocyanine was used in place of the ε-type copper phthalocyanine, and the characteristics of the electrophotographic photoreceptor were measured in the same manner as in Example 2. The measurement results are also listed in Table 1.

Comparative Example 1 A photoreceptor was manufactured in exactly the same manner as in Example 1 except that the solvent in the composition of the charge generation layer forming liquid was replaced with tetrahydrofuran, and the characteristics of the electrophotographic photoreceptor were measured in the same manner as in Example 1. . The measurement results are also listed in Table 1.

Comparative Example 2 A photoreceptor was manufactured in exactly the same manner as in Example 2 except that the solvent in the charge generation layer forming liquid composition was replaced with tetrahydrofuran, and the electrophotographic photoreceptor characteristics were measured in the same manner as in Example 1. . The measurement results are also listed in Table 1.

Comparative Example 3 A photoreceptor was manufactured in exactly the same manner as in Example 3 except that the solvent in the composition of the charge generation layer forming liquid was replaced with tetrahydrofuran, and the characteristics of the electrophotographic photoreceptor were measured in the same manner as in Example 1. . The measurement results are also listed in Table 1.

Table 1 [Effects of the Invention] The photoreceptor having a laminated structure according to the present invention provides a smooth and homogeneous charge generation layer with uniform phthalocyanine particle diameters without causing color separation or whitening (brushing). . Therefore, as can be seen from the results shown in Table 1, the organic photoreceptor of the present invention has excellent electrophotographic photoreceptor characteristics such as sensitivity and strength.

Claims (2)

[Claims] (1) A method for producing a multilayer organic photoreceptor comprising a charge generation layer and a charge transfer layer, the charge generation layer containing phthalocyanine photoconductive fine powder dispersed in a resin,
A method for producing an organic photoreceptor, characterized in that a dioxane/cyclohexanone mixed solvent is used as the charge generation layer forming solvent. (2) The method for producing a photoreceptor according to claim 1, wherein the phthalocyanine photoconductive fine powder is copper phthalocyanine, titanyl phthalocyanine, or metal-free phthalocyanine.