JPH0815875A - Production of organic photosensitive body - Google Patents

Abstract

PURPOSE:To provide a method for producing an org. photosensitive body free of foreign matter in the clean room atmosphere low in cleanliness. CONSTITUTION:A photosensitive layer forming coating soln. is applied to a cylindrical substrate to form a photosensitive layer thereby to produce an org. photosensitive body. In this process, the surface of the substrate to be coated is wiped with a dust-free cloth or paper and cleaned in a clean room atmosphere of class 1000 to 10,000, and then the coating soln. is applied. When the photosensitive layer consists of a charge generating layer and a charge-transfer layer, a charge generating layer forming coating soln. is firstly applied, then the surface of the formed charge generating layer is wiped with a dust-free cloth or paper and cleaned, and then a charge-transfer layer forming coating soln. is preferably applied. This org. photosensitive body is appropriately used in the contact charging system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an organic photosensitive drum which does not cause minute defects even when applied in a low class clean room atmosphere, and more particularly to an organic photosensitive material used in a contact charging system. A method of manufacturing a drum.

[0002]

2. Description of the Related Art An organic photosensitive drum is a cylindrical base on a substrate.
If necessary, the coating liquid for forming the undercoat layer is applied, and then the coating liquid for forming the charge generation layer and the coating liquid for forming the charge transport layer are applied. The presence of foreign matter such as dust in those layers causes image defects when the photosensitive drum is used, and therefore various operations including coating operation are usually performed in a clean room. Clean rooms are in a special environment where dust in the air is removed, and are classified according to the level of dust removal. The cleanness of the clean room atmosphere is represented by the number of dust particles of 0.5 μm or more in 1 ft ³ . (US Federal Standard 209D) To manufacture an organic photosensitive drum, for example, Japanese Patent Laid-Open No. 4-1
As described in Japanese Patent No. 80068, class 10
An atmosphere of 0 or less is preferable. However, class 10
Installing, maintaining, and managing a clean room of 0 or less is particularly inconvenient and time-consuming, and has the inconvenience of restricting manual work. At the level of up to class 10000, this inconvenience is considerably eliminated, it is economically very convenient, and it becomes possible to supply an inexpensive organic photosensitive drum.

[0003]

However, if the class of cleanliness is lowered, even if care is taken, minute dust and foreign matter will adhere to the coating film of the organic photosensitive drum. In particular, when the organic photosensitive drum is used in a contact charging system in which a conductive roll or a blade is brought into contact to perform charging, the presence of foreign matter in the coating film causes a problem.
That is, as described in Japanese Patent Application Laid-Open No. 2-67575, when foreign matter is present in the coating film, the electric charge is concentrated on the foreign matter-attached portion and the current easily leaks. When a leak occurs, the coating film in that portion is destroyed by electric discharge and becomes a pinhole, and the electric charge is not applied, resulting in a white spot (black spot in the reversal phenomenon), which causes a serious image defect. Conventionally, an operation of blowing compressed air with an air gun has been performed in order to blow away foreign matter, but in reality, it is difficult to remove electrostatically adhered small foreign matter of 10 μm or less. Therefore, the present invention has been made in view of the above-mentioned actual situation in the conventional technique. That is, an object of the present invention is to provide a method for producing an organic photoconductor in which a foreign matter does not adhere in a clean room atmosphere having a low degree of cleanliness. Another object of the present invention is to provide a method for producing an organophotoreceptor suitable for use in a contact charging system.

[0004]

The present invention relates to a method for producing an organic photoreceptor in which a photosensitive layer-forming coating solution is applied onto a cylindrical substrate, in a clean room atmosphere of class 1000 to 10000 and before application. The surface of the substrate is wiped clean with a dust-free cloth or paper, and then the photosensitive layer-forming coating liquid is applied. Further, the photosensitive layer is composed of a charge generation layer and a charge transport layer, and after the application of the charge generation layer forming coating liquid, the surface of the formed charge generation layer is wiped again with a dust-free cloth or paper, and then A coating liquid for forming a charge transport layer is applied. The organic photoreceptor produced by the present invention is preferably used in the contact charging system.

The present invention will be described in detail below. In the present invention, the work for forming the photosensitive layer of the organic photoreceptor is class 100.
It is carried out in a clean room atmosphere of 0 to 10,000. In the present invention, classes 1000 and 10
The cleanliness of a clean room atmosphere of 000 is determined by the number of fine particles having a particle size of 0.5 μm or more per 1 ft ^3. The clean room atmosphere of Class 1000 has 1000 fine particles of 0.5 μm or more / ft. ³ or less means a class 10000 clean room atmosphere where particles of 0.5 μm or more are 100
This means a state of 00 / ft ³ or less. In the present invention, first, before forming the photosensitive layer by coating, the surface of the cylindrical substrate is wiped clean with a dust-free cloth or paper.
Adhesion of foreign matter on a cylindrical substrate often occurs in a later step after cleaning the substrate surface. Therefore, by wiping the surface of the cylindrical substrate with a dust-free cloth or paper before coating, the foreign substances that have adhered up to that point can be removed.

As the dust-free cloth or paper, various kinds of wipers for clean rooms are known as commercially available products, and most of them are non-woven fabrics or woven fabrics such as cotton, cellulose, polyester, polypropylene and nylon. It is made of paper or the like. Specifically, for example, Bencott manufactured by Asahi Kasei Co., Ltd., Kimtex manufactured by Jujo Kimberley Co. and the like can be preferably used. The cleaning operation may be performed by appropriately rolling or bending these dust-free cloths or papers, and rubbing the surface of the cylindrical substrate to wipe it off. At that time, it is sufficient to wipe with a dry cloth, but it may be wiped by soaking a small amount of an organic solvent. Although this work can be performed manually, it is preferable to use an industrial robot during mass production. As described above, most of the foreign substances adhering to the surface of the cylindrical substrate can be removed by simply wiping the surface of the cylindrical substrate.
That is, even a small electrostatically adhered foreign matter having a size of 10 μm or less which cannot be removed by blowing compressed air with an air gun is mechanically rubbed off by the above-mentioned cleaning work, and therefore can be easily removed. it can.

In the present invention, as the cylindrical substrate, any conventionally used one can be used, and for example, one made of an alloy such as an aluminum alloy or stainless steel is used.

After the surface of the cylindrical substrate is wiped and cleaned, a photosensitive layer-forming coating liquid is applied to the surface to form a photosensitive layer. It may have a laminated structure composed of a generation layer and a charge transport layer,
Further, an undercoat layer may be provided. These photosensitive layer-constituting layers can be formed by using a coating liquid having a known composition, whereby an organic photosensitive drum is manufactured.

When the undercoat layer, the charge generation layer and the charge transport layer are formed as described above, even after coating each layer,
Since foreign matter may adhere, foreign matter also adheres to the undercoat layer or the charge generation layer. Therefore, it is effective to wipe again with a dust-free cloth or paper before applying the final charge transport layer forming coating liquid. Specifically, the surface of the charge generating layer may be wiped off, but the surface of the charge generating layer is surprisingly resistant to wiping and the film is not damaged or peeled off. However, here, it is preferable to wipe without using an organic solvent.
By this operation, the foreign matter attached to the charge generation layer can be removed, and the organic photosensitive drum free from foreign matter can be manufactured.

[0010]

EXAMPLES In the following examples and comparative examples, the manufacturing process of the organic photosensitive drum was as follows. As a base
A 30 mmφ x 253 mm pipe made of SUS304 is prepared, and its surface is roughened with a grindstone grinder, and the surface roughness is Ra.
= 0.8 μm. Next, 5 parts (weight part, the same hereinafter) of type 8 nylon (laccamide, manufactured by Dainippon Ink and Chemicals, Inc.) was dissolved in 40 parts of methanol and 60 parts of 1-butanol to obtain the coating liquid for forming the undercoat layer. The substrate was applied by dip coating to form an undercoat layer having a film thickness of 1 μm. Subsequently, polyvinyl butyral resin (BM-1, manufactured by Sekisui Chemical Co., Ltd.) 1
Part was dissolved in 19 parts of cyclohexanone, 3 parts of chlorogallium phthalocyanine (see JP-A-5-98181) was added thereto, and the mixture was dispersed by a sand mill. Further, 20 parts of 2-butanone was added to the dispersion liquid, and the obtained coating liquid for forming a charge generation layer was coated on the undercoat layer to form a charge generation layer having a thickness of 0.12 μm. Next, N, N'-diphenyl-
36 parts of N, N '-(m-tolyl) benzidine and 64 parts of polycarbonate Z resin were dissolved in 300 parts of monochlorobenzene. The obtained coating liquid for forming a charge transport layer was applied onto the charge generating layer and dried at 110 ° C. for 30 minutes to form a charge transport layer having a film thickness of 18 μm to obtain an organic photosensitive drum.

In carrying out the above-mentioned steps, each Example and Comparative Example were carried out under the following processing conditions.
Ten organic photosensitive drums were produced. Example 1 An organic photosensitive drum was manufactured in a class 10000 clean room. Then, before applying the coating liquid for forming the undercoat layer, the surface of the substrate was wiped with a wiper made of cotton nonwoven fabric (Bencot, manufactured by Asahi Kasei Corp.). Example 2 Before the coating of the coating liquid for forming the charge transport layer in Example 1, the surface of the charge generating layer was wiped with the same wiper as used for cleaning the substrate. Except for this, the organic photosensitive drum was manufactured in a class 10000 clean room as in Example 1.

Comparative Example 1 An organic photosensitive drum was manufactured in a class 10000 clean room in the same manner as described above except that the surface of the substrate was not wiped. Comparative Example 2 An organic photosensitive drum was manufactured in a class 100 clean room. An organic photosensitive drum was manufactured in the same manner as described above except that the surface of the substrate was not wiped.

Each of the obtained organic photosensitive drums was inspected by a drum inspection machine having the following process. Charging: 12 mm of urethane rubber layer (10 ⁶ Ωcm) with carbon dispersed around a 5 mm diameter stainless steel shaft
A charging roll having a diameter of 10 μm and coated with a nylon resin on the surface is brought into contact with the organic photosensitive drum, and DC-6
50V and AC 1500V (peak difference voltage, 700Hz)
Is applied to the organic photosensitive drum at -650
Uses a method of charging to V. Development: A one-component reversal development method with a bias power supply in which DC-600V and AC1600V (peak difference voltage, 1000Hz) are superimposed. Inspection method: After the organic photosensitive drum is rotated once to be uniformly charged, development is performed (solid white) or the entire surface is exposed and then development (solid black), and the surface is visually inspected.

The inspection results were as follows. Example 1
In the case of one of the 10 organic photosensitive drums, a black dot was generated in a solid white portion. In Example 2,
All the 10 organic photosensitive drums were good products. On the other hand, in the case of Comparative Example 1, out of 10 organic photosensitive drums, black dots were generated in the solid white part in 4 organic photosensitive drums. The black dots were destroyed by electric discharge, but the cause was the adhesion of foreign matter. In Comparative Example 2, all the 10 organic photosensitive drums were non-defective. This was because the cleanliness was high, but maintained the class 100 clean room atmosphere,
It took great care to manage it.

[0015]

EFFECTS OF THE INVENTION Since the present invention has the above-mentioned constitution, it is possible to manufacture an organic photoconductor free from foreign matter adhesion even in a clean room atmosphere of low cleanliness. Therefore,
According to the present invention, it is possible to manufacture an organic photosensitive drum that is free from defects due to adhesion of foreign matter without maintaining and managing high cleanliness. Further, the organic photoconductor manufactured according to the present invention does not cause defects such as leakage due to foreign matter adhesion when used in the contact charging system, and thus is suitable for use in the contact charging system.

Claims (3)

[Claims] 1. A method for producing an organic photoreceptor, which comprises forming a photosensitive layer by applying a photosensitive layer-forming coating liquid on a cylindrical substrate, in a clean room atmosphere of class 1000 to 10000 before coating. A method for producing an organic photoreceptor, which comprises cleaning the surface of a cylindrical substrate with a dust-free cloth or paper to clean it, and then applying a coating solution for forming a photosensitive layer. 2. The photosensitive layer comprises a charge generation layer and a charge transport layer, and after the application of the coating liquid for forming the charge generation layer, the surface of the formed charge generation layer is again made of dust-free cloth or paper. The method for producing an organic photoconductor according to claim 1, wherein the coating liquid for forming the charge transport layer is applied by wiping to clean it. 3. The method for producing an organic photoconductor according to claim 1, wherein the organic photoconductor is used in a contact charging system.