JPH025068A - Production of electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To eliminate image defects such as fogging under wide environmental conditions including high humidity by forming an anodized film onto an aluminum substrate, then physically rubbing the surface of the film and cleaning the film. CONSTITUTION:The anodized film formed on the aluminum substrate or the anodized film subjected to a sealing treatment is rinsed and is then subjected to the physical contact rubbing and cleaning treatment. The meaning of this physical contact rubbing and cleaning treatment lies in that the film surface is cleaned to the extent of removing the greater part of the foreign matter sticking to the film surface. Such sticking material is, therefore, removed and the sufficiently clean anodized film is obtd. The good image which is free from fogging is obtd. in this way under the wide environmental conditions including the high humidity.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing an electrophotographic photoreceptor. More specifically, the present invention relates to a method for manufacturing an electrophotographic photoreceptor having an anodic oxide film, which is used as a substrate for an electrophotographic photoreceptor.

(Prior Art) Image forming systems using electrophotography have been widely applied in the field of copying.

In addition, recently, digital signal data processing systems have progressed and become popular, and there is a desire for improvements in the functionality of so-called printers that print out such data, and the use of electrophotographic printing systems in this field is being considered and put into practical use. has been made into This system converts electrical signal data into optical signals using means such as a laser scanner, LED array, or liquid crystal shutter, and irradiates the light onto a photoreceptor to form an electrostatic latent image on the photoreceptor. visualize,
It is a system for obtaining images, and is also called an optical printer. This method is rapidly becoming popular because it has an extremely high printing speed compared to the conventional impact method, and allows high-quality printing without noise.

As a photoconductor used in such an optical printer, Se
Inorganic photoconductors such as , CdS, As, Se, etc., and organic photoreceptors such as charge transfer complexes of polyvinyl carbazole trinitrofluorenone have been used.
Organic lead conductors are extremely suitable because they are relatively easy to select in the sensitive wavelength range, especially in the near-infrared wavelength region that is the output wavelength of semiconductor lasers, and various materials have been developed.

Among organic photoreceptors, especially laminated photoreceptors consisting of a charge generation layer and a charge transfer layer can make full use of the wide variety of organic compounds, and can provide photoreceptors with high sensitivity and long printing durability. It is also extremely useful in terms of safety and the ability to select non-polluting materials.

(Problem to be Solved by the Invention) On the other hand, as an image forming method with an optical printer, in order to effectively utilize light or increase resolution, a so-called reversal development method is used in which toner is attached to the area irradiated with light to form an image. is often adopted.

In the reversal development method, the dark potential area becomes a white background, and the bright potential area becomes a black background (image area), but in this system, if there is a local charging failure due to a defect on the photoreceptor, the white background becomes If there are black spots or a large number of them, a phenomenon similar to background fog will occur, resulting in significant image defects.

Even if such local charging defects are at a level that causes no problems when used in regular development, they may cause image defects in reversal development, resulting in scratches and scratches. It turned out that there were problems with sunspots and fogging, although there were some differences.

There are various possible causes for this problem, that is, local charging failure, but there are cases where charge injection occurs locally between the conductive support (electrode) and the photoconductive layer, and the charging potential does not increase. it is conceivable that.

In order to improve this problem, it is conceivable to provide a blocking layer between the conductive support and the photoconductive layer. Providing such a blocking layer has been known as a conventional technique, and as a blocking layer, aluminum oxide,
Inorganic layers such as aluminum hydroxide and organic resin layers such as polyvinyl alcohol, casein, sodium caseinate, polyvinylpyrrolidone, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide, and polyamide are used.

However, when photoreceptors having these conventional blocking layers are used in a reversal development system, it is difficult to completely eliminate black spots, and background fog becomes significant, especially under high-humidity environmental conditions.

Furthermore, when used repeatedly in low humidity conditions, the black background potential increases significantly and is often unsuitable for practical use, so further improvements are desired.

Among the blocking layers known so far, one that has a sealed anodic oxide film on an aluminum substrate has relatively low environmental dependence of electrical properties and shows good properties. When used in a reversal development system, image defects such as spots or running patterns appear particularly under high temperature and high humidity conditions, and it is currently quite difficult to obtain a product that can be put to practical use.

(Means for Solving the Problem) The inventors of the present invention have investigated the background fog, minute sunspots, etc. of an electrophotographic photoreceptor using an aluminum substrate having an anodic oxide film, which is used particularly in the reversal development method as described above. As a result of intensive studies to solve the problem, we found that in the process of forming the anodic oxide film, by using a substrate that has undergone a specific post-treatment after anodizing the aluminum substrate, it can be used under a wide range of environmental conditions, including high humidity. The present inventors have discovered that a photoreceptor with good characteristics without background fog or other image defects can be obtained, and has thus arrived at the present invention.

That is, the gist of the present invention is to provide a method for manufacturing an electrophotographic photoreceptor in which a photoconductive layer is provided on an aluminum substrate having an anodic oxide film, after forming an anodized film on the aluminum substrate, the surface of the film is physically removed. The present invention relates to a method for manufacturing an electrophotographic photoreceptor, which comprises contact scrubbing and cleaning.

The present invention will be explained in detail below.

The aluminum substrate used in the present invention is preferably degreased by various degreasing methods such as acid, alkali, organic solvent, surfactant, emulsion, and electrolysis before being anodized. Anodized coatings are usually formed by anodizing in an acid bath, such as chromic acid, sulfuric acid, oxalic acid, boric acid, or sulfamino acid, but the best results are obtained by anodizing in sulfuric acid. give.

For anodization in sulfuric acid, the sulfuric acid concentration is 700-300
'i/1. Dissolved aluminum concentration is 2~/, tf7/1
, the liquid temperature is /j~30''C1 electrolytic voltage is ~20V, the current density is preferably set in the range of -2A/dm2.The average thickness of the anodic oxide film is usually 2
It is preferably formed to have a thickness of 0 μm or less, particularly 7 μm or less.

The obtained anodized coating can be used as it is, but since it is porous, it has poor weather resistance and is prone to corrosion, so it is preferable to perform a treatment to seal the pores, that is, a sealing treatment. good.

Such sealing treatment includes a low-temperature sealing treatment in which the anodic oxide film formed as described above is immersed in an aqueous solution containing nickel fluoride as a main component, or an aqueous solution containing nickel acetate as a main component, for example. A high-temperature sealing treatment is performed by immersing the material in the container.

The concentration of the nickel fluoride aqueous solution used in the low-temperature sealing treatment can be selected as appropriate, but it is most effective when used within the range of 3 to 61/L.

In order to proceed with the sealing process smoothly, the treatment temperature should be 25-30°C, preferably 30-30°C. ;”C
Also, the pH of the nickel fluoride aqueous solution is /4j to 6. It is preferable to process in the range jJ-B, 0.

p) (As a regulator, oxalic acid, boric acid, formic acid, acetic acid,
Sodium hydroxide, sodium acetate, ammonia water, etc. can be used.

The treatment time is preferably within the range of t to 3 minutes per 1 μm of average film thickness of the coating. In order to further improve the physical properties of the film, nickel fluoride, cobalt acetate, nickel sulfate,
A surfactant or the like may be added to the nickel fluoride aqueous solution.

- Tsu - As a sealing agent in the case of high-temperature sealing treatment, an aqueous solution of metal salts such as nickel acetate, cobalt acetate, lead acetate, nickel-cobalt acetate, and barium nitrate can be used, but it is particularly difficult to use nickel acetate. is preferred.

When using a nickel acetate aqueous solution, the concentration is 3 to 209
It is preferable to use it within the range of /l. Processing temperature is 6J
The temperature is preferably 100°C to 100°C, and the pH of the aqueous nickel acetate solution is preferably in the range of t, o - t, .

Here, aqueous ammonia, sodium acetate, etc. can be used as the pH adjuster. In this case, sodium acetate, organic carboxylate,
Anionic or nonionic surfactants may be added to the nickel acetate aqueous solution.

The anodic oxide film formed as described above or the anodic oxide film that has been subjected to the sealing treatment is usually washed with water and then subjected to the physical contact and cleaning treatment according to the present invention.

The meaning of the physical contact scrubbing treatment of the present invention is to clean the coating surface to the extent that most of the foreign matter adhering to it is removed. When sprayed onto the surface of the surface, the cleaning process is to the extent that foreign matter is removed to the extent that a substantially uniform film of water droplets is formed.

In this scrubbing, it is preferable to use the following scrubbing material in the form of a brush, foam, or cloth.

As rubbing materials, natural fibers such as cotton, rayon, cellulose, and wool; synthetic fibers such as polyester, nylon, acrylic, and acetate; polystyrene, polyethylene,
Thermoplastic plastic foams such as polypropylene; thermosetting plastic foams such as polyurethane and polyurea can be used.

The rubbing cleaning method includes a method in which the rubbing material is brought into contact with the anodic oxide film, and the rubbing material is rotated mechanically or manually while supplying a solvent such as water, methanol, or ingropanol; A method of scrubbing and cleaning by reciprocating, a method of cleaning by reciprocating while rotating, etc. can be used.

In the above-mentioned sealing treatment, the use of heavy metal salt aqueous solutions as mentioned above is more advantageous and effective in terms of production than other steam sealing methods, but on the other hand, heavy metal salts and other substances may be present on the coating surface. It has the disadvantage that foreign objects tend to stick to it.

In contrast, in the manufacturing method of the present invention, it has been found that such stuck substances can be removed by performing a physical contact scrubbing treatment after the sealing treatment, and a sufficiently clean anodic oxide coating can be obtained. Ta.

A photoconductive layer is provided on the anodic oxide film formed as described above, but other treatments such as providing an organic resin layer in the blocking layer described above between the anodic oxide film and the photoconductive layer may also be applied. good. Various inorganic and organic photoconductive layers can be used as the photoconductive layer, such as a laminated photoconductive layer consisting of a charge generation layer and a charge transfer layer, and a photoconductive layer in a binder consisting of a charge transfer material and a binder resin. Although there is a dispersed photoconductive layer formed by dispersing body particles, it is extremely useful to use a laminated photoconductive layer.

In this case, the photoconductor used for the charge generation layer is Se.
Various organic pigments such as arsenic-hetamine, cadmium sulfide, other inorganic photoconductors, phthalocyanines, azo dyes, quinacridones, and polycyclic quinones can be used. Among them, thermal metal phthalocyanines; phthalocyanines coordinated with metals such as copper, indium chloride, gallium chloride, tin, oxytitanium, zinc, and vanadium, or their oxides and chlorides; azo-order such as monoazo, bisazo, trisazo, and polyazo; phase is preferred.

The charge generation layer is formed as a uniform layer of these materials or dispersed in a binder resin. Examples of the binder resin used here include phenoxy, epoxy, polyester, acrylic, polyvinyl butyral, polybonate resin, and the like. The film thickness is usually 0.l~/μm1, preferably 0.1/μm1. / , f ~ 0.6 μm
is suitable. The content of these photoconductors is usually 20 to 300 parts, preferably 30 to 30 parts by weight, based on 700 parts by weight of the binder resin.
Used within the scope of the section.

As the charge transfer material in the charge transfer layer, high molecular compounds such as polyvinylcarbazole, poly)novinylpyrene, and horacenaphthylene, or low molecular compounds such as various pyrazoline derivatives, oxazole derivatives, hydrazone derivatives, and stilbene derivatives can be used.

A binder resin is blended with these charge transfer materials as necessary. Preferred binder resins include:
Examples include vinyl polymers such as polymethyl methacrylate, polystyrene, and polyvinyl chloride, copolymers thereof, polycarbonates, polyesters, phenoxy, epoxy, and silicone resins, and partially crosslinked cured products thereof are also used. Further, the content of these charge transfer materials is usually 30,200 parts, preferably in the range of 5-6 to 750 parts, based on 100 parts of the binder resin.
Further, the charge transfer layer may contain various additives such as an antioxidant and a sensitizer, if necessary. What is the thickness of the charge transfer layer? The thickness is preferably 70 to 304 m, preferably 70 to 304 m.

In the case of a dispersion type, the above-mentioned photoconductor and charge transfer material are used in combination, and 20,
The amount used is 200 parts, preferably ≠0 to ljO parts.

(Effects of the Invention) When the electrophotographic photoreceptor obtained by the present invention is used in an electrophotographic system including a reversal development process,
Good images without fog can be obtained under a wide range of environmental conditions, including high humidity.

(Examples) The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to the following Examples unless the gist thereof is exceeded.

Example 1 A thick aluminum cylinder with a mirror-finished surface was treated with a degreaser, NG-H30 (manufactured by Kizai ■) 3ofI/
Degreasing was carried out in an aqueous solution at 60° C. for one evening. Subsequently, after washing with water, it was immersed in 7% nitric acid at 2j''C for 7 minutes. After further washing with water, it was immersed in sulfuric acid electrolyte (
Dissolved aluminum concentration 71/l) Ha2 A/d
Anodic oxidation was performed at a current density of H2 to form an anodized film with an average thickness of 1 μm. Next, after washing with water, 70 fl/ml of Top Seal DX-SOO (manufactured by Okuno Pharmaceutical Co., Ltd.), a high-temperature sealant whose main component is nickel acetate, was added to an aqueous solution. J-″C
It was immersed in water for 30 minutes to seal the holes. After washing with water, the entire surface of the coating was rubbed back and forth three times using a polyester sponge. Then, it was washed with water and dried.

On the other hand, 10 parts by weight of oxytitanium phthalocyanine, polyvinyl butyral (manufactured by Tanemizu Chemical Co., Ltd., trade name Kosuretsuk BH-3>!; 00 parts by weight of 2-dimethoxyethane were added to the parts by weight, and the mixture was ground and dispersed with a sand grind mill. The aluminum cylinder provided with the previously formed anodic oxide film was applied by dip coating to this dispersion, and a charge generation layer was provided so that the film thickness after drying was 03tμm.

Next, in this aluminum cylinder, the following hydrazone compound sty weight part and H8 the following hydrazone compound/≠ weight part, cyanide compound/J weight part and polycarbonate resin (manufactured by Mitsubishi Kasei ■, Tubarex (registered trademark) 7030A) ) 100 parts by weight / 100 parts by weight of Cudioxane is applied by dip coating in a solution,
A charge transfer layer was provided so that the film thickness after drying was 778 m. The drum thus obtained is referred to as photoreceptor A.

Example 1 Photoreceptor B was prepared in the same manner as in Example 7, except that a cellulose sponge was used instead of the contact scrubbing using a polyester sponge in Example 1.

Comparative Example Example 1 was carried out in the same manner as in Example 1 except that physical contact scrubbing was not performed and photoconductors C were washed and dried after sealing. It was installed in a reversal development type laser printer, and the image characteristics under various environments were evaluated. As a result, for both photoreceptors A and B in Example, j °C // 0% (RH) 1,
! ! 'C760% (RH), 3 j 'C: /
f, t% (r(H)) Good images were obtained for both white background and black background images under any environmental conditions. Under environmental conditions, many stain-like image defects appeared on the white background image, and a good image could not be obtained.

From the above results, it can be judged that the electrophotographic photoreceptor manufactured by the manufacturing method of the present invention has extremely excellent performance.

Claims (1)

[Claims] (1) In a method for manufacturing an electrophotographic photoreceptor in which a photoconductive layer is provided on an aluminum substrate having an anodized film,
A method for producing an electrophotographic photoreceptor, which comprises forming an anodic oxide film on an aluminum substrate, and then physically contacting and scrubbing the surface of the film.