JPH07295241A - Method of manufacturing organic photoreceptor for electrophotography - Google Patents

Abstract

(57) [Abstract] [Purpose] The outer surface of a cylindrical substrate made of an Al material is treated by a novel method, resulting in good adhesion between the substrate and the photosensitive layer and high reliability, and excellent electrical and image characteristics. Provided is a method for easily and stably producing a photosensitive body of the type described above. [Structure] The outer surface of a cylindrical substrate made of an Al material is degreased and washed, and subsequently immersed in a hot pure water bath at a temperature of 60 ° C. to 90 ° C. and a specific resistance of 1 MΩ or more to form a hydrated oxide film.
A photosensitive layer containing an organic photoconductive material is formed on the surface thereof. The formation of a film can be promoted by using a warm weak alkaline aqueous solution instead of the warm pure water bath. Further, it is preferable to perform a heat treatment at 100 ° C. to 150 ° C. for 5 minutes to 30 minutes after the film formation because the film becomes stable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an electrophotographic organic photoconductor, and more particularly to a method for treating the surface of a substrate.

[0002]

2. Description of the Related Art Organic photoconductors using an organic photoconductive material have become popular as electrophotographic photoconductors as image forming members mounted in electrophotographic devices such as copying machines and printers to which electrophotographic technology is applied. ing. The organic photoconductor is usually formed by forming a photosensitive layer containing an organic photoconductive material on the outer surface of a cylindrical substrate made of aluminum or aluminum alloy (hereinafter referred to as Al material).

In such a photoreceptor, the adhesion between the substrate and the photosensitive layer is an important factor in terms of its reliability and environmental adaptability. In order to obtain good adhesion that is practically sufficient, A
It is known that it is effective to form an anodized film by processing the outer surface of a cylindrical substrate made of 1-material to a suitable surface roughness by cutting or the like, and further subjecting it to anodization.

[0004]

However, in order to form an anodic oxide film which gives a photoreceptor having good adhesion between the substrate and the photosensitive layer and high reliability, and excellent electrical and image characteristics. Includes anodizing conditions during film formation,
It is necessary to properly select and precisely control the sealing treatment conditions, and a high level of technology is required. In addition, this requires expensive equipment. On the other hand, in order to steadily grow the market of electrophotographic devices, it is desired to provide a high-quality, long-life and inexpensive photoreceptor. For this reason, it has been desired to improve the cylindrical substrate made of an Al material, which accounts for a large proportion of the product cost, and the surface treatment method thereof.

The present invention has been made in view of the above-mentioned points, and provides a novel surface treatment method for a cylindrical substrate made of an Al material, and the adhesion between the substrate and the photosensitive layer is good and the reliability is high. It is an object of the present invention to provide a method for easily, stably and inexpensively manufacturing a photoconductor having high electrical characteristics and excellent electric characteristics and image characteristics.

[0006]

According to the present invention, the above problem is solved by degreasing and cleaning the outer surface of a cylindrical substrate made of an Al material, and subsequently, at a temperature of 60 to 90 ° C. and a specific resistance of 1 MΩ.
The problem can be solved by forming a hydrated oxide film by immersing it in a bath of hot pure water as described above, and then forming a photosensitive layer containing an organic photoconductive material on its surface to manufacture a photoreceptor.
The time of immersion in a bath of warm pure water is preferably 10 to 180 seconds.

The cylindrical substrate on which the hydrated oxide film is formed as described above is further heated at a temperature of 100 ° C. to 150 ° C. for 5 hours.
After heat treatment for 30 minutes to 30 minutes, it is more preferable to form a photosensitive layer containing an organic photoconductive material on the surface thereof. Also, instead of using a warm pure water bath with a specific resistance of 1 MΩ or more
You may use the bath of 9 or less weak alkaline aqueous solution. Ammonia, amines, alcohol amines, amides, etc. are added to the pure water to weaken the alkali.

It is desirable to control the temperature variation within the bath in which the cylindrical substrate is dipped within 3 ° C. For that purpose, it is preferable to adopt a method in which the shape of the bath is cylindrical and the liquid is circulated.

[0009]

When the surface of the Al material is exposed to the atmosphere, it is oxidized by oxygen in the atmosphere and covered with a thin film of alumina (Al ₂ O ₃ ), and the Al material is not further corroded in the dry atmosphere. . However, includes the usual water content in the atmosphere, the surface of the alumina film is hydrated by absorbing moisture in the atmosphere bayerite (Al ₂ 0 ₃ ·
3H ₂ O). The film thickness of such a hydrated oxide film is about 10Å in the atmosphere of normal temperature and humidity, but when it is immersed in warm water, it becomes thick rapidly and becomes several hundreds Å to several thousand Å, and the surface area of Al material is dramatically increased. Increase. The bayerite film produced in this manner is more stable when dried, and thus boehmite (A
L ₂ 0 ₃ · H ₂ O). Such boehmite formation is promoted by aging treatment at a temperature of about 90 ° C. or higher.

As a result of studying the above points, the present inventors immerse a cylindrical substrate made of an Al material used for a photoreceptor in warm water to form such a hydrated oxide film on the surface. After that, when a photosensitive layer of an organic material is formed on the surface of the photosensitive layer, the contact area between the substrate and the photosensitive layer is significantly increased, and the adhesiveness can be significantly improved. I found that I could get a body. In that case, it is important to use pure water having a specific resistance of 1 MΩ or more. By using such warm pure water, a good quality hydrated oxide film can be uniformly formed, and a good photosensitive layer can be formed thereon. The temperature of the hot pure water is preferably 60 ° C to 90 ° C. If the temperature is low, the rate of film formation will be slow, and if the temperature is too high, convection or boiling will make it impossible to form a uniform film.

If a weak alkaline aqueous solution obtained by adding a small amount of ammonia, amine, alcohol amine, amide, etc. to pure water is used instead of pure water as described above, the rate of formation of such a hydrated oxide film can be increased. it can. However, if the alkalinity of the liquid becomes too high, a high-quality hydrated oxide film will not be formed, so it is necessary to keep the pH below 9.

Although the hydrated oxide film formed as described above is mostly bayerite, it can be converted to more stable boehmite by further heat treatment, and the substrate can be easily handled. Adhesion does not change even when boehmite is used. Heat treatment temperature is 100 ℃ ~ 150 ℃
Is desirable. If the temperature is lower than this, the boehmite hardly progresses, and if the temperature is higher than the above range, the substrate is deformed, which is not preferable. The processing time may be 5 minutes to 30 minutes.

When an Al material is used as the substrate of the photoconductor, the film thickness of the hydrated oxide film is preferably 50Å to 1000Å in consideration of electrical characteristics and image characteristics. For that purpose, the immersion time of the substrate in the warm water bath may be 10 seconds to 180 seconds.

[0014]

Embodiments of the present invention will be described below. Example 1 As a substrate of a photoconductor, a non-cutting and drawing-finished cylindrical substrate made of an Al material having a surface roughness R _max of 0.5 μm or less is used. After degreasing this substrate,
Immerse in a warm pure water bath at a temperature of 70 ° C. and a specific resistance of 2 MΩ for 60 seconds, perform a warm water treatment of pulling up from the bath at a speed of 1 cm / sec, and naturally cool to room temperature, and then add an organic photoconductive material to it. A photosensitive layer was formed to prepare a photoconductor of Example 1-1. Further, after the substrate was treated with warm water and naturally cooled as described above, it was further subjected to a heat treatment at a temperature of 100 ° C. for 15 minutes, and then a photosensitive layer was similarly formed on the surface of the substrate to form a photosensitive layer of Example 1-2. The body was made. Further, a photosensitive layer was similarly formed on the surface of the substrate that had been subjected to only degreasing treatment, and Example 1
-3 photoconductor was prepared.

With respect to these photoreceptors, the adhesion between the substrate and the photosensitive layer, potential characteristics, image quality and reliability were evaluated, and the results shown in Table 1 were obtained. Adhesion is evaluated by a film peeling test using an adhesive tape, and reliability is temperature 60 ° C, relative humidity 90
% And evaluated by an accelerated film peeling test when left for 1000 hours.

[0016]

[Table 1]

Regarding the adhesion, the photoconductors of Examples 1-1 and 1-2 which have been treated with hot water have an adhesion strength about three times as high as that of the photoconductor of Example 1-3 which has not been treated with hot water. Had. Regarding the reliability, the photoconductor of Example 1-3 was unsatisfactory in the film peeling test after being left for about 250 hours, but the photoconductors of Examples 1-1 and 1-2 were good even after being left for 1000 hours. Met. Regarding the potential characteristics, Example 1-3
The photoreceptors of Examples 1-1 and 1-2 showed a slight improvement in the potential holding characteristics after charging as compared with the photoreceptor of Example 1. This is considered to be the blocking effect of the hydrated oxide film formed on the substrate surface. Regarding the image quality, Examples 1-1 and 1
Almost no superiority or inferiority was recognized with respect to each of the photoreceptors of -2 and 1-3.

Example 2 As a substrate of a photosensitive member, the surface roughness R was the same as in Example 1.
A cylindrical substrate made of Al material finished to a _max of 0.5 μm or less and without cutting was used. After degreasing the substrate, 0.1 wt% of triethanol was used instead of the warm pure water bath having a specific resistance of 2 MΩ. %, A photoreceptor was prepared in the same manner as in Example 1 except that a warm weak alkaline aqueous solution bath was added, and the bath dipping time was about 1/3 of that in Examples 1-1 and 1- A photoconductor having characteristics equivalent to 2 was obtained.

Example 3 Regarding the shape of the bath used for forming the hydrated oxide film, the stability of the film formation was examined by using a rectangular bathtub and a cylindrical bathtub with or without liquid circulation. As a result, the hydrated oxide film can be formed most uniformly and stably when the bath shape is cylindrical and the liquid is circulated. By controlling the variation of the bath temperature within 3 ° C, the film thickness of the film can be controlled. The deviation of variation could be suppressed to within ± 10%, and a photosensitive member sufficient for actual use could be manufactured.

As described above, practically sufficient adhesion between the base and the photosensitive layer can be obtained by immersing the base made of the Al material in warm pure water or a weakly alkaline aqueous solution, and the conventional anode can be used. It becomes possible to easily and inexpensively manufacture the photoconductor as compared with the case of performing the oxidation treatment. Also,
In the above example, the cylinder without drawing finish is used as it is as the base. Since it is not necessary to machine the outer surface of the substrate into a proper surface roughness by cutting as in the conventional case, the effect of obtaining a more inexpensive photoreceptor can be obtained.

[0021]

According to the present invention, the outer surface of a cylindrical substrate made of aluminum or aluminum alloy is degreased and washed, and subsequently immersed in a bath of hot pure water having a temperature of 60 ° C. to 90 ° C. and a specific resistance of 1 MΩ or more. After forming a hydrated oxide film, a photosensitive layer containing an organic photoconductive material is formed on the surface of the hydrated oxide film, so that the adhesion between the substrate and the photosensitive layer is good and the reliability is high. It is possible to easily and stably manufacture a photoreceptor having excellent characteristics at a low cost.

Further, by forming the hydrated oxide film as described above and further subjecting it to a heat treatment at a temperature of 100 ° C. to 150 ° C. for 5 minutes to 30 minutes, the film becomes stable and the substrate becomes easy to handle, and the photoreceptor is Is easy to manufacture.
When a weak alkaline aqueous solution having a pH of 9 or less is used in place of pure water when forming the hydrated oxide film, the necessary hydrated oxide film can be formed in a shorter time.

At this time, it is desirable to form a hydrated oxide film with a small variation in film thickness. For that purpose, it is necessary to reduce the variation in temperature in the bath in which the cylindrical substrate is dipped as much as possible. If it is within the range, it is practically sufficient. For that purpose, it is effective to make the shape of the bath for immersing the cylindrical substrate cylindrical so as to circulate the liquid.

Claims (6)

[Claims] 1. An outer surface of a cylindrical substrate made of aluminum or an aluminum alloy is degreased and washed, and then a temperature of 60.
Characterized by forming a hydrated oxide film on the surface by immersing it in a warm pure water bath having a specific resistance of 1 MΩ or more at 90 ° C to 90 ° C, and then forming a photosensitive layer containing an organic photoconductive material on the surface And a method for producing an organic photoconductor for electrophotography. 2. An outer surface of a cylindrical substrate made of aluminum or an aluminum alloy is degreased and washed, and then a temperature of 60.
After immersing in a warm pure water bath with a specific resistance of 1 MΩ or more at ℃ to 90 ℃ to form a hydrated oxide film, heat treatment at 100 ℃ to 150 ℃ for 5 to 30 minutes, and then to the surface of the organic light A method of manufacturing an organic photoreceptor for electrophotography, which comprises forming a photosensitive layer containing a conductive material. 3. An outer surface of a cylindrical substrate made of aluminum or an aluminum alloy is degreased and washed, and then a temperature of 60.
Characterized by forming a hydrated oxide film on the surface by immersing it in a bath of a weak alkaline aqueous solution of 90 ° C to 90 ° C and a pH of 9 or less, and then forming a photosensitive layer containing an organic photoconductive material on the surface And a method for producing an organic photoconductor for electrophotography. 4. An outer surface of a cylindrical substrate made of aluminum or an aluminum alloy is degreased and washed, and then a temperature of 60.
℃ to 90 ℃, pH 9 or less dipping in a weak alkaline aqueous solution bath to form a hydrated oxide film, further 100 ℃
A method for producing an organic photoconductor for electrophotography, which comprises performing a heat treatment at 50 to 150 ° C. for 5 minutes to 30 minutes and then forming a photosensitive layer containing an organic photoconductive material on the surface thereof. 5. The method for producing an organic photoconductor for electrophotography according to claim 1, wherein variation in temperature in the bath in which the cylindrical substrate is immersed is controlled within 3 ° C. 6. The method for producing an organic photoconductor for electrophotography according to claim 5, wherein the bath for immersing the cylindrical substrate has a cylindrical shape and the substrate is immersed while circulating a liquid.