JPH02226253A - Production of organic photosensitive body - Google Patents

Abstract

PURPOSE:To prevent the generation of the irregular reflection of incident light owing to clouding in the copying stage and to advantageously produce the org. photosensitive body having excellent sensitivity by using a solvent essentially consisting of dioxane as a coating liquid solvent for a charge transfer layer. CONSTITUTION:A charge generating layer and the charge transfer layer are formed on the org. photosensitive body. This transfer layer is made into a lamination type consisting of a charge transfer org. material and a polycarbonate resin. The solvent essentially consisting of the dioxane is used as the coating liquid solvent for forming the charge transfer layer at the time of producing this org. photosensitive body. The gelation and flocculation of the polycarbonate resin in the coating liquid are averted in this way. The generation of the irregular reflection of the incident light owing to clouding is prevented in a copying stage and the org. photosensitive body having the excellent sensitivity is advantageously produced. The solvent essentially consisting of the dioxane is used in a 300 to 1,000pts.wt. range per 100pts.wt. polycarbonate.

Description

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

[Conventional technology and its problems]

As an organic photoreceptor, a laminated type photoreceptor is known in which the function of the photosensitive layer is separated into a charge generation layer and a charge transfer layer. For example, polycarbonate resin is used as a binder resin in the charge transfer layer of the laminated organic photoreceptor. In a conventional method, a charge transport layer is formed by dissolving a polycarbonate resin together with a charge transport organic material in tetrahydrofuran and applying this solution onto a charge generating layer formed on a conductive substrate.

However, when using tetrahydrofuran as a solvent,
Although the effect is small during the preparation of the coating solution, there is a problem in that the polycarbonate resin gels over time.

Due to this gelation phenomenon, the viscosity of the charge transfer coating liquid increases, and at the same time, cloudiness occurs. As it progresses further, it aggregates. Therefore, even if the charge transport layer can be applied, the incident light cannot sufficiently reach the charge generation layer during the copying process due to diffuse reflection due to cloudiness. Therefore, the sensitivity of the photosensitive layer decreases.

[Problem of invention]

An object of the present invention is to solve the above-mentioned problems found in the prior art and to provide a method that can advantageously produce an organic photoreceptor with excellent sensitivity.

[Means to solve the problem]

As a result of intensive research aimed at solving the above problem, the present inventors have found that the problem can be solved by using a solvent containing dioxane as a main component as the coating liquid solvent for the charge transfer layer. This discovery led to the completion of the present invention.

That is, according to the present invention, in the method for manufacturing a multilayer organic photoreceptor comprising a charge generation layer and a charge transport layer, the charge transport layer comprising a charge transport organic substance and a polycarbonate resin, a method for forming the charge transport layer is provided. A method for manufacturing an organic photoreceptor is provided, which is characterized in that a solvent containing dioxane as a main component is used as a coating liquid solvent.

In the present invention, as a coating liquid solvent for forming a charge transfer layer containing a polycarbonate resin as a binder,
A solvent containing dioxane as a main component is used. Thereby, gelation and aggregation of the polycarbonate resin in the coating liquid can be avoided. In this case, dioxane can be used alone or in a mixture with other solvents. As other solvents, for example, solvents that are soluble not only in the polycarbonate resin but also in the charge transfer organic substance, such as tetrahydrofuran, dichloroethane, and cyclohexanone, are used. The mixing ratio of other solvents to dioxane is 0 to 100 parts by weight, preferably 0 to 70 parts by weight, and preferably 10 to 50 parts by weight, based on 100 parts by weight of dioxane. If the mixing ratio of other solvents becomes too large, gelation or aggregation of the polycarbonate resin will occur.

In the present invention, the coating liquid for forming a charge transfer layer can be obtained by dissolving a polycarbonate resin and a charge transfer organic substance in the above-mentioned solvent containing dioxane as a main component.

As the charge transfer organic substance, conventionally known substances can be used. Examples of such compounds include pyrazoline compounds (Japanese Patent Publication No. 60-225860), hydrazone compounds (Japanese Patent Publication No. 55-42380 or 61-2315).
No. 4), ethylene derivatives (JP-A-59-165064)
, butadiene compound (JP-A-62-287257), and the like. In the present invention, in particular, the following general formula (
Preference is given to using pyrazoline compounds of the formula 1) and hydrazone compounds of the formula -maximum (n).

(In the formula, R1, R2, R8 and R4 represent a lower alkyl group, and X represents an optionally substituted phenyl group) (In the formula, R1 and R2 represent a lower alkyl group, R3, R4,
(R1+ represents hydrogen or a lower alkyl group) The solvent containing dioxane as a main component is 300 to 1000 parts by weight, preferably 500 to 1000 parts by weight, more preferably 6 parts by weight, based on 100 parts by weight of the polycarbonate resin.
It is used in a range of 00 to 900 parts by weight. If the amount is less than 300 parts by weight, the polycarbonate resin will not be completely dissolved in the solvent, or even once dissolved, gelation will occur over time, making it impossible to form a charge transfer layer. 10
If it exceeds 0.00 parts by weight, the viscosity of the resin liquid in which the polycarbonate resin is dissolved will be low, making it difficult to apply the solution.

The polycarbonate resin used as a binder resin in the charge transfer layer is preferably a conventionally known one, for example, one having a molecular weight of 24,000 to 30,000 obtained by reacting bisphenol A with carbonyl chloride in the presence of an acid binder and a solvent. It will be done.

The preferred composition of the coating solution for the charge transfer layer is as follows: the concentration in the solvent is 8 to 13% by weight of the charge transfer organic substance, preferably 10% by weight.
~120-12 weight agent polycarbonate resin 8-13% by weight, preferably 10-12% by weight.

The charge generation layer used in the present invention can be formed according to a conventionally known method. In this case, the coating liquid used is a solution in which a resin is dissolved in an organic solvent and a charge generating substance is dispersed therein. As the charge generating material, a conventionally known material such as phthalocyanine photoconductive fine powder can be used. Examples of these include copper phthalocyanine, titanyl phthalocyanine, metal-free phthalocyanine, and the like. Its average particle size is 0.05~O0
≦voice, preferably 0.05 to 0.1 voice. Furthermore, examples of the resin (binder) for adhering such fine powder to the support include polyester resin, polyvinyl butyral resin, polymethyl methacrylate resin, phenoxy resin, and phenol resin.

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 the binder resin used is 60 to 200 parts by weight based on 100 parts by weight of the phthalocyanine photoconductive fine powder. As the organic solvent, tetrahydrofuran or a dioxane/cyclohexanone mixed solvent is used. When using a dioxane/cyclohexanone solvent, the mixing ratio is 3 to 10 parts of cyclohexanone to 100 parts by weight of dioxane.
The proportion is 0 parts by weight, preferably 5 to 50 parts by weight. Further, by using this mixed solvent, a charge generating layer with excellent sensitivity and strength can be obtained. The preferred composition of the coating solution for forming a charge generation layer is as follows: the charge generation substance is 0.5 to 3% by weight, preferably 1 to 3% by weight, and the binder resin is 0.5 to 5% by weight in the solvent. , preferably 1 to 3% by weight.

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

First, a coating liquid for forming a charge generation layer is applied onto a conductive substrate to form a charge generation layer. The thickness of the charge generation layer at this time is suitably 2.0 microns or less, preferably 0.1 to 0.5 microns. Next, a coating liquid for forming a charge transfer layer is applied onto the charge generation layer to form a charge transfer layer, thereby producing a laminated organic photoreceptor. The appropriate thickness of the charge transfer layer at this time is 14 to 20 microns. In this way, a laminated organic photoreceptor can be obtained.

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

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〕

Next, the present invention will be explained in more detail with reference to Examples.

Example I Type X metal-free phthalocyanine 5 parts by weight The above composition was subjected to ultrasonic dispersion for 1 hour to prepare a coating liquid for forming a charge generation layer. The resulting dispersion was applied using a wire bar onto a 75 micron thick aluminum-deposited PET film and dried to form a charge generation layer 0.3 micron thick.

[Composition of coating liquid for charge transfer layer formation]

The above composition was stirred and dissolved using a stirrer. Then, the state of gelation or aggregation of the coating solution was observed, and the results are shown in Table 1. This liquid was applied onto the charge generation layer formed above 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). The surface potential at this time was measured (initial potential Vo).

Further, the surface potential of the photoreceptor was measured after leaving it in a dark place for 5 seconds (dark decay potential Vs). Next, light irradiation was performed from a tungsten lamp at a surface illuminance of 10 lux, and the photosensitivity E1/2 and E115 were measured by measuring the time until the surface potential decreased to 172 or 115. The results are shown in Table 2.

Example 2 In Example 1, in the coating liquid composition for charge transfer layer formation, the mixed solvent was dioxane/dichloroethane (weight ratio = 100
150) was used, and the state of gelation or aggregation of the coating liquid for charge transfer layer formation was observed. The results are also listed in Table 1, and Example 1
The electrophotographic characteristics were measured in the same manner as in
Also listed in the table.

Example 3 In Example 1, in the coating liquid composition for charge transfer layer formation, the mixed solvent was dioxane/cyclohexanone (weight ratio = 10
A photoreceptor was manufactured in exactly the same manner except that 0/10) was used, and the state of gelation or aggregation of the charge transfer layer forming coating liquid was observed, and the results are also listed in Table 1. Further, electrophotographic properties were measured in the same manner as in Example 1, and the results are also listed in Table 2.

Comparative Example 1 Of the coating liquid composition for charge transfer layer formation in Example 1, the mixed solvent was cyclohexanone/dichloromethane (weight ratio = 1/4).
) The photoreceptor was manufactured in exactly the same way, except that
The state of gelation or aggregation of the coating solution for forming the charge transfer layer was observed, and the results are also listed in Table 1.The electrophotographic properties were also measured in the same manner as in Example 1, and the results were reported in Table 2. Also listed in the table.

Comparative Example 2 A photoreceptor was manufactured in exactly the same manner as in Example 1 except that the mixed solvent in the composition of the coating solution for forming a charge transfer layer was changed to tetrahydrofuran, and the coating solution for forming a charge transfer layer was gelled. Alternatively, the state of aggregation was observed, and the results are also listed in Table 1. In a coating liquid using a tetrahydrofuran solvent, 2.
A thickening phenomenon was observed after 3 days, and if left as it was, it progressed further and became cloudy and agglomerated. Therefore, it was not possible to form a charge transport layer.

Table 1 [Effects of the Invention] According to the present invention, as can be seen from the results shown in Table 1, a coating liquid for forming a charge transfer layer that does not cause gelation or aggregation can be obtained. Therefore, an organic photoreceptor having a charge transfer layer formed from such a coating liquid has excellent sensitivity and strength as shown in Table 2.

Claims (4)

[Claims] (1) In a method for manufacturing a multilayer organic photoreceptor comprising a charge generation layer and a charge transfer layer, the charge transfer layer comprising a charge transfer organic substance and a polycarbonate resin, as a coating liquid solvent for forming the charge transfer layer. , a method for producing an organic photoreceptor, characterized in that a solvent containing dioxane as a main component is used. (2) Add 300 to 100 parts by weight of the dioxane-based solvent to 100 parts by weight of the polycarbonate resin.
2. The method of claim 1, wherein amounts in the range of 0 parts by weight are used. (3) The method according to claim 1 or 2, wherein the solvent containing dioxane as a main component is a mixture of 0 to 100 parts by weight of another solvent to 100 parts by weight of dioxane. (4) The method according to any one of claims 1 to 3, wherein the solvent mixed with dioxane is at least one selected from tetrahydrofuran, dichloroethane, and cyclohexanone.