JPS63214759A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To prevent black spots by sealing pinholes of the anodized film on an aluminum substrate with a sealant composed essentially of nickel fluoride. CONSTITUTION:The pinhole treatment is executed by dipping the anodized film formed on the aluminum substrate into an aqueous solution containing nickel fluoride as a main component in the most effective concentration of 3-6g/l, preferably, at a temperature of 25-40 deg.C and a pH of 4.5-6.5. A preferable thickness of the sealed anodized film is 0.5-20nm. It is preferred to form the laminate type photoconductive layer composed of an electric charge generating layer and a charge transfer layer on the anodized film. Since this sealing step can be processed at low temperature, occurrence of defects, such as uneven drying, on the surface of the anodized film is reduced.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an electrophotographic photoreceptor.

Specifically, the invention relates to an electrophotographic photoreceptor used in a reversal development process.

[Conventional technology]

Image forming systems using electrophotography have been widely applied in the field of copying, and various excellent inorganic and organic photoreceptors have been developed for use in these systems.

On the other hand, recently, digital signal data processing systems have progressed and become popular, and there is a desire to improve the functionality of so-called printers that print out these data, and the use of electrophotographic printing systems in this field is being considered and put into practical use. It is becoming more and more popular.

That is, this system converts electrical signal data into an original signal using means such as a laser beam converter, an LED array, or a liquid crystal shutter, and then irradiates the signal onto a photoreceptor. An electrostatic image is formed on the photoreceptor, and this image is visualized by toner development to obtain an image. This process is also called an optical IJ printer.

Compared to the conventional impact method, this method is rapidly becoming popular because it has extremely high printing speed, produces no noise, and is capable of high-quality printing.

As a photoconductor used in such an optical printer, Se,
Inorganic photoconductors such as Ccls and organic photoconductors such as a CT complex of PVK (polyvinyl carbazole) totrinitrofluorenone have been used.

Organic photoconductors, which are relatively easy to make sensitive to
Various materials have been developed that are extremely suitable as photoreceptors for optical printers. In particular, a laminated organic photoconductor consisting of a charge generation layer and a charge transfer layer can make full use of the rich variety of organic compounds, so that a photoreceptor with high sensitivity and high printing durability can be obtained. Furthermore, this organic photoconductor is extremely useful in terms of safety as it allows selection of non-polluting materials.

On the other hand, as an image forming method with an optical printer, a so-called reversal development method is adopted, in which toner is attached to the area irradiated with light to form an image, in order to effectively utilize light or increase the dissolving power. many.

In the reversal development process, the dark potential area becomes a white background,
The bright potential area becomes the black background area (image area).

In this system, if there is a local charging failure due to a defect or the like on the photoreceptor, black spots appear on a white background, or if there are a large number of these, a background fog-like development occurs, resulting in a significant image defect. Even if such local charging defects are at a level that would not cause any problems when used in regular development, images are likely to become unnecessary in reversal development, and moreover, the conventionally available laminated type It has been found that the photoreceptor has problems such as sunspots and fogging, although the degree varies.

Various causes can be considered for this problem, that is, local charging failure, but it is thought that charge injection occurs locally between the conductive support, which is an electrode, and the photosensitive layer.

Providing such a blocking layer is a conventionally known technique, and its materials include inorganic layers such as aluminum oxide and aluminum hydroxide, polyvinyl alcohol,
Resin layers such as casein, polyvinylpyrrolidone, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyhydride, and polyamide are used.

[Problem that the invention seeks to solve]

However, even if a photoreceptor having such a conventional blocking layer is used in a reversal development process, it is difficult to completely eliminate black spots. Particularly under high humidity environmental conditions, the background fog is so severe that it is often not practical, and further improvements have been desired.

[Means for solving problems]

Therefore, the inventors of the present invention have conducted extensive studies in order to solve the problems such as background fog and minute black spots of electrophotographic photoreceptors used in the reversal development process as described above. It has been discovered that by using an aluminum substrate with a treated anodic oxide film, it is possible to obtain a photoreceptor with no background fog and good characteristics under a wide range of environmental conditions, including high humidity. Ta.

That is, the gist of the present invention is to provide an electrophotographic photoreceptor in which a conductive layer is provided on an aluminum substrate having an anodized film, in which the anodic oxide film is sealed with a sealant containing nickel fluoride. There are some electrophotographic photoreceptors that are characterized by:

The present invention will be explained in detail below.

The photoreceptor of the present invention is provided on an aluminum substrate having an anodized film subjected to a specific pore sealing treatment.

The aluminum base is preferably degreased by various degreasing methods such as acid, alkali, solvent, surfactant, emulsion, or electrolysis before being anodized.

The anodic oxide film is usually formed by anodizing in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, phosphoric acid, or sulfamic acid. In this case, the voltage is 2~
/lOV, current density is 0. / , j It is preferable to set within the range of A/d-.

A sealing treatment is performed by immersing the anodic layered coating formed at 5K in an aqueous solution containing nickel fufluoride as a product, thereby obtaining the anodic oxide coating of the present invention.

The concentration of nickel fluoride used here can be selected as appropriate, but it is most effective when used within the range of 3 to 7t.

In addition, in order to proceed smoothly with the sealing process, the degree of 1 treatment part is 1
1 to 410°C, preferably 30 to 31°C, and the pH of the nickel fluoride aqueous solution! -6,! ,Preferably! ,
! It is preferable to set it within the range of -4.0. As the PHU4 moderating agent, silicic acid, ho17&#, formic acid, acetic acid, etc. can be used.

In addition, in order to further improve the physical properties of the film, cobalt fluoride, nickel acetate, nickel sulfate, etc. may be added to the nickel fluoride aqueous solution. Then, the sealing process is completed by washing with water and drying.

The thickness of the anodic oxide film subjected to such sealing treatment is usually θ0. It is preferably t-10 μm1, especially -1.0 μm.

The photoconductive layer provided on such an anodic oxide film includes:
Although layers of inorganic and organic photoconductors can be used, it is particularly advantageous to use a laminated photoconductor consisting of a charge generation layer and a charge transfer layer.

In this case, the charge generation layer may include 8e and its alloy, arsenic-silicon, cadmium sulfide, and other inorganic light 4N!
Vegetable organic pigments such as botanicals, phthalocyanines, azo pigments, meso-nacridones, and polycyclic quinones can be used. Among them, Focus Jl
t7 Talocyanine/copper, indiwaum chloride, gallium chloride, tin, metals such as titanium chloride, zinc, panadicum, etc. or their oxides, chloride-coordinated phthalocyanines, azo pigments such as monoazo, bisazo, trisazo, polyazo. is preferred.

The charge generation layer is formed as a uniform layer of these substances or in a state in which these fine particles are dispersed in a binder resin. The binder resin used here is
Examples include phenolic resin, ebonized resin, polyester, acrylic, polyvinyl butyral, and polycarbonate resin. The thickness of the charge generation layer is usually 0. /~71m, preferably 0. /j~0.4 μm is suitable.

As the charge transfer material in the charge transfer layer, high molecular compounds such as polyvinylcarbazole, polyvinylpyrene, and polyacenaphthylene, 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 polymethyl methacrylate, polystyrene, vinyl polymers such as polyvinyl chloride, and copolymers thereof, polycarbonate, polyester,
Examples include phenoxy, ebonoxy resin, silicone resin, and partially crosslinked cured products of these resins.

Further, the charge transfer layer may contain various additives such as an antioxidant and a sensitizer, if necessary.

The thickness of the charge transport layer is usually 70 to 30 μm, preferably 1
Preferably, it is s-at μm.

〔Effect of the invention〕

The sealing treatment using a sealant containing nickel fluoride as a product used in the present invention can be performed at a lower temperature than ordinary hydration sealing, nickel acetate sealing, etc., so the alumite surface after treatment When used in an electrophotographic system including a drying and reversal development process, good images without fog can be obtained under a wide range of environmental conditions, including high humidity.

〔Example〕

EXAMPLES The present invention will be described in more detail with reference to Examples below, but the present invention is not limited to the following Examples unless it exceeds the gist thereof.

Example 1 An aluminum cylinder with a wall thickness of /■ with a mirror-finished surface was degreased and cleaned in an aqueous solution of degreaser Pa T-j r 08 (manufactured by Henkel Hakusui Co., Ltd.) at 60°C for 5 minutes. Ta.

Subsequently, after washing with water, 7. Anodic oxidation was carried out at a current density of -2 A/d- to form an anodic oxide film of ≦μ-゛.

After washing with water, nickel fluoride j, 91/, prepared with p'fi/- and OVc using acetic acid, was immersed in an aqueous solution at 31°C for 5 minutes to seal the holes. Subsequently, it was thoroughly washed with pure water and dried.

Next, 70 parts by weight of Shichitani 9 muftalocyanine and polyvinyl butyral (1 Eslec BH manufactured by Tanezu Chemical Industry Co., Ltd.) were added.
-J") 7 parts by weight, 1.-1 dimethane!00
Parts by weight were added, and the mixture was ground and dispersed using a sand grind mill.

An aluminum cylinder, which had previously been provided with an anodic oxide film, was dip-coated in this dispersion, and a charge generation layer was provided so that the film thickness after drying was 00 μm.

Next, this aluminum cylinder was mixed with 10 parts by weight of the following hydrazone compound and j1 CH.

20 parts by weight of the following hydrazone compound and 100 parts by weight of polycarbonate resin (1 Novarettas 70JOA'' manufactured by Mitsubishi Chemical Corporation) were applied by dip coating in a solution in which 7 parts by weight of g-dioxane and 7 oOa were dissolved, and the film was dried. A charge transfer layer 5 was provided to have a thickness of 105 m.

The drum obtained in this way is called a photosensitive great person.

Example In Example 1, a commercially available nickel fluoride sealant - Anodal C8-, 2'' (8ANDOZ
K, made by IC)! Photoreceptor B was prepared in the same manner as in Example 1, except that the photoconductor B was immersed in a 11/L aqueous solution at JO 0 C for 5 minutes and sealed.

Example 3 In Example 1, a sealant containing commercially available nickel fluoride 1 Hard 9 All/i6J" (Nicca Chemical Industry ■
A photoreceptor C was prepared in the same manner as in Example 1, except that zi7 (manufactured by Mimaki Co., Ltd.) was immersed in an aqueous solution at 33° C. for 5 minutes and sealed.

Comparative Example 1 In Example 1, a commercially available nickel acetate sealing agent @DX-400'' (manufactured by Okuno Pharmaceutical Co., Ltd.) 71/ was immersed in an aqueous solution at 90°C for 10 minutes to perform a sealing treatment. A photoreceptor was prepared in the same manner as in Example 1 except for the following steps.

Comparative Example: In Example 1, in pure water? ! 'C: A photoreceptor E was prepared in the same manner as in Example 1, except that the photoreceptor was immersed for 20 minutes and sealed.

Comparative Example 3 Photoreceptor F was prepared in the same manner as in Example 1 in Example/Vc except that the sealing treatment was not performed.

Comparative Example: A charge generating layer and a charge transporting layer were provided directly on the cylinder with a mirror-finished surface in the same manner as in the Example.
I created G.

Next, these photoreceptors were installed in a commercially available copying machine that had been modified to have an inversion mode, and the image characteristics under various environmental conditions were evaluated. The results are shown in Table 7.
%C, a good image with no fogging or minute black spots was obtained under any conditions, but with the photoreceptors of comparative examples, fogging occurred under high temperature and high humidity at 41, making it unsuitable for practical use. It turned out to be too insufferable.

As is clear from the results shown in Table 1, the electrophotographic photoreceptor having an anodic oxide film and having pores sealed with the pore sealant containing nickel fluoride of the present invention has excellent performance. I know that there is.

Claims (1)

[Claims] (1) An electrophotographic photoreceptor in which a photoconductive layer is provided on an aluminum substrate having an anodic oxide film, characterized in that the anodic oxide film is sealed with a sealant containing nickel fluoride as a component. An electrophotographic photoreceptor.