JPH10148956A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electrophotographic photoreceptor not causing streaky defects on a halftone image and giving a satisfactory image. SOLUTION: This electrophotographic photoreceptor has at least an org. photoconductive layer on the Al substrate obtd. by extruding an Al alloy contg. 0.1-0.6wt.% Si and 0.3-0.9wt.% Mg, heating the resultant substrate at 400-550 deg.C and anodically oxidizing the surface of the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member. In particular, the present invention relates to an electrophotographic photosensitive member having a good image.

[0002]

2. Description of the Related Art F. The electrophotographic technology according to Carlson's invention has been widely used in various printers and facsimile machines in recent years, not only in the field of copiers, but also in the field of copiers, because of its ability to obtain images with immediacy, high quality and high storability. Is showing. This electrophotographic process is basically performed by uniformly charging a photoreceptor, forming an electrostatic latent image by image exposure, developing the latent image with toner, and transferring the toner image to paper (intermediately through a transfer member). In some cases) and an image forming process by fixing.

[0003] Photoconductors, which are the core of the electrophotographic technology, have been developed from conventional inorganic photoconductors such as selenium, arsenic-selenium alloys, cadmium sulfide, and zinc oxide as photoconductive materials. A photoreceptor using an organic photoconductive material, which has advantages such as easy film formation and easy production, has been developed. Among them, a so-called laminated photoreceptor in which a charge generation layer and a charge transport layer are laminated, a photoreceptor with higher sensitivity can be obtained, a photoreceptor with a wide selection range of materials can be obtained, and coating can be performed. Due to its high productivity and relatively low cost, photoconductors are now the mainstream and are produced in large quantities.

However, a laminated photoreceptor using an organic photoconductive material is susceptible to noise from a substrate, particularly when the charge generation layer is a dispersion film in which a pigment is dispersed in a resin. There were drawbacks. In particular, when this is used as a laser printer, minute black spots (called fog) are generated in a white image at the time of reversal development, and a countermeasure has been required. As one of the countermeasures, it has been proposed and put into practice that anodizing treatment is performed on the surface of the base and sealing treatment is performed in a solution containing nickel ions.
On the other hand, as a material of an aluminum substrate used for an electrophotographic photoreceptor having an organic photoconductive layer, an Al-Mg-Si alloy (JIS 6000 series) is particularly preferred because of its surface workability and the like. Alloy) is often used. (JP-A-1-180936)
No.)

[0005]

Recently, as the resolution of copiers and printers has been increased, electrophotographic photosensitive members to be used have been required to have high sensitivity. As a result, when a high-sensitivity electrophotographic photosensitive member is used, noise from the substrate is more easily picked up than in the conventional product. Under these circumstances, a specific streak-like image defect occurs in an electrophotographic photoreceptor using an Al-Mg-Si-based alloy as a raw material and a substrate having an anodized surface. It has become.

[0006]

Means for Solving the Problems The inventors of the present invention have found that the crystal structure of the base portion corresponding to the position where the streak-like defect has occurred on the image and the crystal structure of the base portion corresponding to the position where the streak-like defect has not occurred on the image are considered. A comparison was made. As a result, it was found that the portion where the streak-like defect occurs had a smaller crystal size and a smaller amount of Mg ₂ Si crystal than the normal portion. That is, Mg
_{2 Since the} portion having a small size and small amount of Si has a relatively large α-phase portion, a stripe having a different gloss is formed by anodizing treatment. After forming an electrophotographic photosensitive member, this portion is streaked on an image. It was found to appear as a state defect.

As described above, the defect is caused by Mg ₂ S on the substrate.
If the distribution of i is not uniform, this defect can be eliminated by making the distribution of Mg ₂ Si uniform over the entire substrate.
As a result of the study by the present inventors, after extruding the material, 4
Heat treatment was performed at a temperature of 00 ° C. to 550 ° C. to dissolve Mg and Si into Al once, and then, if the entire substrate was cooled uniformly, it was found that Mg ₂ Si was uniformly distributed throughout the substrate. The invention has been reached.

That is, the gist of the present invention is to provide an electrophotographic photoreceptor having at least an organic photoconductive layer on an aluminum substrate, wherein the aluminum substrate contains 0.1% by weight of Si.
An aluminum alloy containing 0.3 wt% to 0.6 wt%, Mg; 0.3 wt% to 0.9 wt%, and extruding the material, followed by heat treatment at a temperature of 400 ° C to 550 ° C; An electrophotographic photoreceptor characterized in that the surface of the substrate has been subjected to an anodic oxidation treatment. Further, the electrophotographic photosensitive member, wherein the organic photoconductive layer has at least a charge generating layer and a charge transport layer, the electrophotographic photosensitive member, characterized by containing oxytitanium phthalocyanine as a charge generating material. Exist.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The conductive substrate of the electrophotographic photoreceptor used in the present invention contains Si; 0.1% by weight to 0.6% by weight;
It consists of an aluminum alloy containing 0.3% to 0.9% by weight. The conductive substrate is formed by extruding an aluminum billet into an extruded tube by a porthole method, a mandrel method, or the like, and then performing a heat treatment at a temperature of 400 to 550 ° C. If the heating temperature is lower than 400 ° C., Mg and Si cannot be dissolved in aluminum. If the heating temperature exceeds 550 ° C., a part of the aluminum base is dissolved. (Refer to FIG. 2 for the structure and properties of aluminum (Light Metal Society of Japan) p. 279). The heat treatment time varies depending on the thickness of the substrate, but is generally 20 minutes.
Minutes or more are preferred.

Further, in order to form a cylinder having a predetermined thickness and an outer diameter, after performing mirror finishing such as drawing or cutting, an anodic oxide film is formed on the surface of the substrate. As the conditions of the anodic oxidation treatment, conventionally known conditions can be arbitrarily selected and adopted. Specifically, sulfuric acid, oxalic acid, phosphoric acid, or the like can be used as the anodizing electrolytic solution. Of these electrolytes, sulfuric acid is preferred.
In the case of sulfuric acid alumite treatment, the sulfuric acid concentration in the electrolyte is 10
The temperature of the electrolyte is preferably selected from the range of 0 to 300 g / L and the temperature of the electrolyte is preferably 10 to 30 ° C. The energization time is appropriately determined depending on the desired thickness of the anodized film. The thickness of the anodic oxide film is suitably in the range of 2 to 15 μm.

The substrate used for the electrophotographic photoreceptor of the present invention produced as described above is subjected to anodizing treatment and then sealing treatment according to a conventional method. As the sealing treatment liquid, a conventional sealing treatment liquid such as a liquid containing nickel ions (for example, a liquid containing nickel acetate, a liquid containing nickel fluoride) can be used, and the ordinary processing conditions can be applied to each of them. . A photoconductive layer is provided on the conductive substrate treated as described above. As the photoconductive layer, any of a layer in which a charge generating layer containing a charge generating substance and a charge transporting layer are laminated in this order, a layer in which the charge generating layer is laminated in reverse order, and a so-called dispersion type in which charge generating substance particles are dispersed in a charge transporting medium are used. However, a laminated photoconductive layer having a charge generation layer and a charge transport layer is preferred.

Examples of the charge generating substance include selenium and its alloys, arsenic-selenium, cadmium sulfide, zinc oxide, other inorganic photoconductors, azo pigments such as Sudan Red, Diane Blue, and Dienas Green B, disazo pigments, and algol. Quinone pigments such as yellow and pyrene quinone, quinocyanine pigments, perylene pigments, indigo pigments, bisbenzimidazole pigments such as indofast orange toner,
Examples include phthalocyanine pigments such as copper phthalocyanine, quinacridone pigments, pyrylium salts, and azurenium salts.
Among them, oxytitanium phthalocyanine is preferred.

As the charge transporting substance, polyaromatic compounds such as anthracene, pyrene, phenanthrene, coronene or indole, carbazole, oxazole, isoxazole, thiazole, imidazole, pyrazole, oxadiazole, pyrazoline, Examples thereof include compounds having a skeleton of a nitrogen-containing cyclic compound such as thiadiazole and triazole, and other hole transport substances such as hydrazone compounds.

Examples of the binder resin for forming the photosensitive coating film include polycarbonate, polyarylate, polystyrene, polymethacrylates, styrene-methyl methacrylate copolymer, polyester, styrene-acrylonitrile copolymer, polysulfone, etc. Vinyl, polyacrylonitrile, polyvinyl butyral,
Examples include polyvinylpyrrolidone, methylcellulose, hydroxymethylcellulose, and cellulose esters.

As the coating solvent, a solvent having high volatility and having a vapor density higher than that of air is preferably used. For example, n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, N, N-dimethylformamide, acetone,
Methyl ethyl ketone, cyclohexanone, benzene, 4
-Methoxy-4-methyl-2-pentanone, dimethoxymethane, dimethoxyethane, 2,4-pentadione, anisole, methyl 3-oxobutanoate, monochlorobenzene, toluene, xylene, chloroform, 1,2-dichloroethane, dichloromethane, tetrahydrofuran,
Dioxane, methanol, ethanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide,
Methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate and the like can be mentioned.

A coating solution of a photoreceptor material for producing a single-layer type electrophotographic photoreceptor is prepared by mixing the above-mentioned charge generating substance, charge transporting substance, binder resin and coating solvent.
Further, the coating solution for the photoreceptor material in the case of manufacturing a laminated electrophotographic photoreceptor includes a coating solution for a charge generating layer comprising the above-described charge generating substance, a binder resin and a coating solvent, and the above-described charge transporting substance. And a coating solution for a charge transport layer comprising a binder resin and a coating solvent are separately prepared.

The concentration of each component in the coating solution is appropriately selected according to a known method. The concentration of the solid content is mainly determined according to the thickness of the layer to be formed. However, in the case of a coating solution for producing a single-layer type electrophotographic photoreceptor and for producing a laminated type electrophotographic photoreceptor, 40% by weight or less, preferably 10 to 35%,
It is adjusted to not more than% by weight. In the case of these coating solutions, the viscosity is 50 to 300 cps, preferably 70 cps.
２５０250 cps and the dry film thickness are preferably 15-40 μm.

In the case of the coating solution for the charge generation layer, the solid content concentration is preferably 15% by weight or less, and more preferably 1 to 10% by weight, and the dry film thickness is usually 0.1 to 1 μm. Are suitable. The above coating is usually performed by dip coating, that is, by dipping the cylindrical substrate vertically in a dipping tank in which the coating liquid is overflowing and dipping it in the coating liquid, and then raising the cylindrical substrate vertically and pulling it up. Will be

[0019]

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to the following examples unless it exceeds the gist of the present invention. Example 1 An aluminum alloy containing 0.15% by weight of Si and 0.65% by weight of Mg was extruded to produce an extruded tube having an outer diameter of 69 mm and an inner diameter of 63 mm. This extruded tube is 4m long
After that, heat treatment was performed in a furnace at 500 ° C. for 2 hours. Furthermore, it is subjected to drawing, cutting and cutting, and the outer diameter is 65m.
m, an aluminum cylinder having a length of 348 mm and a wall thickness of 1 mm. This aluminum cylinder was degreased and washed in a 40 g / L aqueous solution of a degreasing agent Fine Cleaner 315 (manufactured by Nippon Parker Rising) at 65 ° C. for 10 minutes. Subsequently, after washing with water, it was immersed in 25% 7% nitric acid for 1 minute.

Further, after washing with water, a 180 g / L sulfuric acid electrolyte solution
1.2A / dm in medium (dissolved aluminum concentration 7g / L)
^TwoAnodization is performed at a current density of
An oxide film was formed. Then, after washing with water, nickel acetate was added.
Alumite sealer, a high-temperature sealant based on Nippon Chemical
10 g / L aqueous solution of Sangyo Co., Ltd. at 95 ° C for 30 minutes
It was immersed and sealed. Then wash and dry
Was. On the other hand, 1 part of oxytitanium phthalocyanine
Vinyl butyral (# 6000C manufactured by Denki Kagaku Kogyo)
0.5 parts of 4-methoxy-4-methyl-2-pentanone
To a mixed solution of 10 parts of and 90 parts of dimethoxyethane,
After dispersion treatment with a sand glider,
0.3g / m after drying on the cylinder ^Twobecome
To form a charge generation layer.

On the thus obtained charge generating layer, 95 parts of a hydrazone compound having the following structure, 100 parts of a polycarbonate resin (manufactured by Mitsubishi Chemical Corporation: "NOVAREX" (trademark) 7030A), and octadecyl-3 − (3,
5-Di-t-butyl-4-hydroxyphenyl) propionate (manufactured by Ciba-Geigy: "Irganox 107
6)) A charge transport layer was formed by applying a solution obtained by dissolving 2 parts in 900 parts of tetrahydrofuran so as to have a dried film thickness of 17 μm.

[0022]

Embedded image The drum thus obtained was designated as photoconductor A.

Example 2 Example 1 except that an aluminum alloy containing 0.45% by weight of Si and 0.50% by weight of Mg was extruded.
In the same manner as in the above, Photoconductor B was prepared. Example 3 Example 1 except that an aluminum alloy containing 0.58% by weight of Si and 0.86% by weight of Mg was extruded.
In the same manner as in the above, Photoconductor C was prepared.

Comparative Example 1 A photoreceptor D was prepared in the same manner as in Example 1 except that the extruded tube was cut and then subjected to drawing without heating treatment in a furnace. Comparative Example 2 A photoreceptor E was produced in the same manner as in Example 2 except that the extruded tube was cut and then subjected to drawing without heating in a furnace. Comparative Example 3 A photoconductor F was produced in the same manner as in Example 3, except that the extruded tube was cut and then subjected to drawing without heating in a furnace.

Comparative Example 4 In Example 1, after cutting the extruded tube, it was heated at 320 ° C.
A photoconductor G was prepared in the same manner as in Example 1, except that the heat treatment was performed for an hour. Comparative Example 5 In Example 2, after cutting the extruded tube, it was heated at 320 ° C.
A photoconductor H was prepared in the same manner as in Example 2, except that the heat treatment was performed for an hour. Comparative Example 6 In Example 3, after cutting the extruded tube, the extruded tube was heated at 320 ° C.
Photoconductor I was prepared in the same manner as in Example 3 except that the heat treatment was performed for a period of time.

These photoconductors A, B, C, D, E, F,
G, H, I modified for reversal development, process speed 1
The apparatus was mounted on a copying machine of 90 mm / sec, a halftone image was actually photographed, and the occurrence of streak-like defects was compared. Table 1 shows the results. In Table 1, ○ indicates no generation of streak-like defects, X indicates occurrence of thin streak-like defects, and XX indicates occurrence of dark streak-like defects.

[0027]

[Table 1]

As can be seen from Table 1, the occurrence of streak-like defects on the halftone image is good for A, B and C, and D, E and F.
Was very bad, and G, H and I were thin but occurred.

[0029]

As described above, according to the present invention, it is possible to provide an electrophotographic photoreceptor having a good image free from streak-like defects on a halftone image.

Claims (3)

[Claims] 1. An electrophotographic photoreceptor having at least an organic photoconductive layer on an aluminum substrate, wherein the aluminum substrate contains 0.1% to 0.6% by weight of Si;
g; consisting of an aluminum alloy containing 0.3% to 0.9% by weight and extruding the material to 40%;
An electrophotographic photoreceptor, wherein a heat treatment is performed at a temperature of 0 ° C. to 550 ° C., and an anodizing treatment is further performed on the surface of the substrate. 2. The electrophotographic photoreceptor according to claim 1, wherein the organic photoconductive layer has at least a charge generation layer and a charge transport layer. 3. The electrophotographic photoreceptor according to claim 1, further comprising oxytitanium phthalocyanine as a charge generating substance.