JP3257177B2 - Electroconductive substrate for electrophotographic photoreceptor and photoreceptor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive substrate for an electrophotographic photosensitive member and a photosensitive member. More specifically, the present invention particularly relates to a conductive substrate for an electrophotographic photosensitive member and a photosensitive member used in an apparatus for forming an image using an electrophotographic process in which coherent light is used as a light source, such as a laser printer.

[0002]

2. Description of the Related Art In recent years, electrophotographic technology has been widely used and applied not only in the field of copiers but also in the field of various printers because of its immediacy and high-quality images. For photoconductors, which are the core of electrophotographic technology, their photoconductive materials include inorganic photoconductors such as conventional selenium, arsenic-selenium alloy, cadmium sulfide, zinc oxide and amorphous silicon, and recently organic compounds. Organic photoreceptors constituted by variously combining such charge generating agents and charge transporting agents have been developed and widely used.

[0003]

When these photoreceptors are mounted on a copying machine or a printer using LED light as a light source to form an image, a good image can be obtained without any problem. When coherent light such as laser is used in an electrophotographic process in which light is used as a light source, moire-like shading occurs in an image, and a good image cannot be formed in many cases, which is a serious problem.

The following can be considered as a cause of this. That is, since the irradiated light is coherent light, interference occurs between reflected light on the surface of the photoconductor and light reflected from inside the photoconductor. Here, as the reflected light from the inside of the photoconductor, the reflected light from the substrate, and the reflected light from the interface of each layer in the case of a laminated photoconductor composed of an organic charge generation layer and a charge transport layer and an amorphous silicon photoconductor composed of multiple layers. Can be considered. Eventually, it is considered that as a result of such interference, the intensity of light is generated, the light irradiation on the photoconductor and the developing potential become non-uniform, and the image appears as moiré-like unevenness in density. This phenomenon is particularly noticeable when a halftone image is taken. Various methods have been proposed to improve such shading unevenness. For example, a method of lowering the reflectance of a substrate by subjecting a substrate made of aluminum to black alumite treatment (Japanese Patent Laid-Open No.
Japanese Patent Application Laid-Open No. 1-188860), similarly, a method of matte-finishing the surface of a base by mechanical cutting, a method of sandblasting, and a method of etching
Etc. are known. However, these methods may be insufficiently effective or cause problems such as contamination of the surface of the substrate during the treatment process. Therefore, more reliable and effective methods are desired.

[0005]

Means for Solving the Problems The present inventors have made intensive studies in order to solve such a problem, and as a result, have found that an electrophotographic photosensitive member using an anodically oxidized conductive substrate after an etching treatment with a specific etching agent. The present inventors have found that the body can form a good image with no uneven shading even in an electrophotographic process using coherent light as a light source, and arrived at the present invention.

That is, the gist of the present invention consists of aluminum or an aluminum alloy which has been subjected to anodizing treatment after etching with an etching agent containing a hydroxide of an alkali metal and a weak acid salt of an alkali metal and / or an alkaline earth metal. The present invention relates to a conductive substrate for an electrophotographic photosensitive member and an electrophotographic photosensitive member using the conductive substrate.

Hereinafter, the present invention will be described in detail. The conductive substrate for an electrophotographic photosensitive member of the present invention is made of aluminum or an aluminum alloy. The conductive substrate is subjected to an anodic oxidation treatment after the etching treatment with an etching agent, and as a pretreatment for these treatments, a degreasing treatment is performed using various degreasing cleaning methods such as an acid, an alkali, an organic solvent, a surfactant, an emulsion, and electrolysis. Is preferably performed.

[0008] The conductive substrate thus degreased is then subjected to an etching treatment with an etching agent according to the present invention. The etching agent used here contains an alkali metal hydroxide and a weak acid salt of an alkali metal and / or an alkaline earth metal as active ingredients. As the alkali metal hydroxide, sodium hydroxide and potassium hydroxide are preferable. The weak acid salt of an alkali metal or an alkaline earth metal may be a normal salt or a hydrogen salt. Examples of the alkali metal include sodium and potassium, and examples of the alkaline earth metal include magnesium and calcium. . Examples of the weak acid used for the weak acid salt of an alkali metal or an alkaline earth metal include inorganic acids such as carbonic acid, phosphoric acid, and silicic acid, and organic acids such as acetic acid, tartaric acid, and succinic acid. Ka (K
a: a dissociation constant as an acid) of 2 or more, and more preferably 3 or more. The proportions of the alkali metal hydroxide and the alkali metal or alkaline earth metal weak acid salt in the etching agent can be changed as appropriate, but preferably each is 6%.
0 to 90% by weight, 10 to 30% by weight, more preferably 70 to 85% by weight and 10 to 25% by weight, respectively.
In addition, a surfactant and an alkali metal chloride may be contained as a liquid property improving agent for performing uniform etching. The concentration, the processing temperature, and the processing time of the etching agent aqueous solution can be appropriately selected. For example, the concentration is 0.5% to 10%.
%, Especially 0.5% to 5%, and the processing temperature is 40%.
C. to 80.degree. C., especially 40.degree. C. to 60.degree. C., and the treatment time is preferably 1 minute to 15 minutes. If the aluminum substrate is immersed in the aqueous solution of the etching agent as it is, the aluminum substrate is rapidly etched. To avoid this, it is preferable to perform the etching after dissolving the aluminum ions in the aqueous solution of the etching agent in advance. In this case, the dissolved aluminum ion concentration is 0.1 to 2%.
It is preferable to adjust to.

When the etching agent of the present invention is used, it is easier to control the degree of etching and to obtain an appropriate rough surface than in the case of using an alkali metal hydroxide alone. If the roughness of the conductive substrate surface after the etching treatment is too small, interference is likely to occur. On the other hand, if it is too large, a rough surface remains even after a subsequent treatment such as anodizing treatment, and image defects such as fog tend to occur. Therefore, roughness R _max of the surface of the conductive substrate after the etching process (JIS B 0601-1970)
Is preferably about 2 to about 4 μm. Further, the degree of the etching treatment on the surface of the conductive substrate before the photoconductive layer is provided after the treatment such as the anodic oxidation treatment described later
_max (JIS B 0601- 1970) is 0.2 to
It is preferable to adjust so as to be 1.5 μm, and it is more preferable that R _max is 0.5 to 1 μm.

[0010] The conductive substrate thus etched is then subjected to, for example, washing with water, neutralization with an acid, and washing with water. Next, the conductive substrate obtained through the above treatment is subjected to an anodic oxidation treatment. The anodized film is usually formed by anodizing in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, boric acid, and sulfamic acid in which aluminum ions are dissolved. Is preferred. In the case of anodizing treatment in sulfuric acid, the sulfuric acid concentration is 100 to 300 g / 1, the dissolved aluminum ion concentration is 2 to 15 g / 1, the liquid temperature is 10 to 30 ° C, preferably 10 to 25 ° C, and the electrolytic voltage is 5 to 20 V. The current density is preferably set in the range of 0.5 to ² A / dm ² . The average thickness of the anodic oxide coating is usually 20 μm or less, especially 10 μm.
m or less.

[0011] The anodic oxide film thus formed is
A low-temperature sealing treatment or a high-temperature sealing treatment is performed. Nickel fluoride is preferable as the sealing agent in the case of the low-temperature sealing treatment, and the concentration of the nickel fluoride aqueous solution can be appropriately selected.
It is most effective when used in the range of 6 g / 1. In order to smoothly carry out the sealing treatment, the treatment temperature is 25 to 40 ° C., preferably 30 to 35 ° C., and the pH of the nickel fluoride aqueous solution is 4.5 to 6.5, preferably 5.5 to 6 It is better to process within the range. As the pH adjusting agent, oxalic acid, boric acid, formic acid, acetic acid, sodium hydroxide, sodium acetate, aqueous ammonia, and the like can be used. The treatment time is preferably in the range of 1 to 3 minutes per 1 μm of the average film thickness. In order to further improve the physical properties of the film, cobalt acetate, nickel sulfate, a surfactant and the like may be added to the nickel fluoride aqueous solution.

As the sealing agent in the high-temperature sealing treatment, an aqueous solution of a metal salt such as nickel acetate, cobalt acetate, lead acetate, nickel-cobalt acetate, barium nitrate, etc. can be used. Is preferred. When an aqueous nickel acetate solution is used, the concentration is 3 to 20 g /
It is preferable to use within the range of 1. The processing temperature is usually
The temperature is 65 to 100 ° C., preferably 80 to 98 ° C., and the pH of the aqueous nickel acetate solution is 5 to 6, preferably 5.5 to 6. Here, ammonia water, sodium acetate, or the like can be used as the pH adjuster. The processing time is preferably in the range of 2 to 10 minutes per 1 μm of the average thickness of the coating. Also in this case, in order to improve the physical properties of the film, sodium acetate, an organic carboxylate, an anionic or nonionic surfactant may be added to the nickel acetate aqueous solution.

The conductive substrate subjected to the anodizing acid treatment and the sealing treatment as described above is subsequently washed, for example, with water and dried by natural or hot air, and then cooled to room temperature to provide a photoconductive layer. If necessary, an intermediate layer having a barrier function and an adhesive function may be provided between the conductive substrate and the photoconductive layer. As the photoconductive layer, any of an inorganic type and an organic type can be used. As the inorganic photoconductive layer, for example, selenium, arsenic-selenium alloy, cadmium sulfide, zinc oxide or amorphous silicon can be used, and is usually formed by a known method such as vapor deposition, sputtering, or coating. As the organic photoconductive layer, for example, any of a stacked photoconductor in which a charge generation layer and a charge transport layer are stacked, a so-called dispersion type photoconductor in which a charge generation material is dispersed in the charge transport layer, and the like can be used. Here, as the charge generation layer, a vapor-deposited film of an organic pigment such as phthalocyanine or an azo pigment, or a film obtained by dispersing them in a resin, for example, by dipping, spraying, spiral coating, or the like, is formed into a film. Can be used. As the charge transport layer, any of a charge transport material such as a hydrazone derivative and an aromatic amine derivative dispersed in a binder resin, and a polymer charge transport agent such as polyvinyl carbazole can be used. The method can be used. Further, a composite photoconductive layer using an inorganic photoconductive layer as the charge generation layer and an organic photoconductive layer as the charge transport layer can be used.

[0014]

EXAMPLES The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to the following examples unless it exceeds the gist of the invention.

(Example 1) An aluminum cylinder (material 6063) having an outer diameter of 30 mm, a length of 250 mm, and a thickness of 1 mm whose surface was mirror-finished was degreased (trade name: NG- #)
30, in a 30 g / 1 aqueous solution of Kizaki Co., Ltd.)
Degreasing washing was performed at 5 ° C. for 5 minutes. Subsequently, after washing with water, an aqueous solution of an etching agent [P ₃ T651] heated to 50 ° C.
(Henkel Hakusui Co., Ltd., composition: sodium hydroxide 76
%, Sodium carbonate 18%, sodium phosphate 3%, sodium chloride 3%) in a 1.2% aqueous solution of a 0.3% solution of aluminum (material 6063)] for 4 minutes for etching. Then immediately after washing with water 7
% Nitric acid at 25 ° C. for 1 minute. After further washing with water, 180
g / 1 sulfuric acid electrolyte (dissolved aluminum ion concentration 7
g / 1) at an electric current density of 1.2 A / dm ² to form an anodic oxide film having an average film thickness of 6 μm. Then, after washing with water, a high-temperature sealing agent containing nickel acetate as a main component (trade name: Topseal DX-500, Okuno Pharmaceutical Co., Ltd.)
Was immersed in a 10 g / 1 aqueous solution at 95 ° C. for 30 minutes to perform a sealing treatment. Subsequently, the resultant was washed with water while applying ultrasonic waves and then dried.

Next, oxytitanium phthalocyanine 10
Parts by weight, polyvinyl butyral (Electrical Chemical Industry Co., Ltd.)
Manufactured by Denka Butyral 6000C)
500 parts by weight of dimethoxyethane was added, and the mixture was pulverized and dispersed by a sand grind mill. An aluminum cylinder provided with the previously formed anodized film was dip-coated on this dispersion, and a charge generation layer was provided so that the film thickness after drying was 0.4 μm.

Next, 56 parts by weight of N-methylcarbazole-3-carbaldehyde diphenylhydrazone, 14 parts by weight of 3,3-di (4-methoxyphenyl) acrolein diphenylhydrazone, and 4 parts by weight of the aluminum cylinder were used.
-(2,2-dicyanovinyl) phenyl-2,4,5-
Dip-coated in a solution of 1.5 parts by weight of trichlorobenzenesulfonate and 100 parts by weight of a polycarbonate resin (NOVAREX (registered trademark) 7030A, manufactured by Mitsubishi Chemical Corporation) in 1,000 parts by weight of 1,4-dioxane, and dried. The charge transfer layer was provided so that the film thickness afterwards would be 17 μm. The photoreceptor thus obtained is referred to as photoreceptor A.

Example 2 A photoconductor B was prepared in the same manner as in Example 1, except that the etching temperature was changed to 56 ° C.

(Example 3) In Example 1, the concentration of aluminum dissolved in the aqueous solution of the etching agent was set at 0.
Photoconductor C was prepared in the same manner as in Example 1, except that the content was 6%.

Example 4 In Example 1, the etching temperature was set to 50 ° C., and the concentration of the aqueous solution of the etching agent was set to 2.
Photoconductor D was prepared in the same manner as in Example 1, except that the content was set to 0%.

Example 5 In Example 1, the etching temperature was 45 ° C. and the concentration of the aqueous solution of the etching agent was 3.
Photoconductor E was produced in the same manner as in Example 1, except that the concentration of aluminum dissolved in the aqueous solution of the etching agent was set to 0.6%.

Example 6 In Example 1, the etching temperature was 45 ° C., and the concentration of the aqueous solution of the etching agent was 3.
Photoconductor F was produced in the same manner as in Example 1, except that the concentration of aluminum dissolved in the aqueous solution of the etching agent was set to 0.9%.

Example 7 In Example 1, the etching temperature was 45 ° C., and the concentration of the aqueous solution of the etching agent was 4.
Photoconductor G was produced in the same manner as in Example 1, except that the concentration of aluminum dissolved in the aqueous solution of the etching agent was set to 0.6%.

Example 8 In Example 1, the etching temperature was 45 ° C. and the concentration of the aqueous solution of the etching agent was 4.
Photoconductor H was prepared in the same manner as in Example 1, except that the concentration of aluminum dissolved in the aqueous solution of the etching agent was set to 0.9%.

(Comparative Example 1) The same photosensitive layer as in Example 1 was directly provided on an aluminum cylinder (material 6063) having a mirror-finished surface and an outer diameter of 30 mm, a length of 250 mm, and a thickness of 1 mm. Was prepared.

Comparative Example 2 A comparative photosensitive member J was prepared in the same manner as in Example 1, except that the etching treatment was not performed.

Comparative Example 3 A comparative photoreceptor K was prepared in the same manner as in Example 1, except that a 3% aqueous solution of sodium hydroxide was used as an aqueous solution of the etching agent.

Example 9 A photoconductor L was prepared in the same manner as in Example 1, except that an etching agent comprising 85% of sodium hydroxide and 15% of sodium acetate was used.

Example 10 A photoconductor M was prepared in the same manner as in Example 1, except that an etching agent comprising 85% of sodium hydroxide and 15% of sodium hydrogen carbonate was used.

Example 11 In Example 1, 85% of sodium hydroxide and 15% of sodium dihydrogen phosphate were used.
A photoconductor N was prepared in the same manner as in Example 1, except that an etching agent consisting of

Comparative Example 4 A comparative photoreceptor O was prepared in the same manner as in Example 1, except that a 1.02% aqueous solution of sodium hydroxide was used as an aqueous solution of an etching agent.

The roughness R _max (JIS B) of the surface of the conductive substrate after the etching treatment in Examples 1, 9 and 10
0601-1970) were 3.6, 2.2 and 3.8 μm, respectively. Roughness _Rmax (JIS B06) of the conductive substrate surface after the anodizing treatment in Example-1
01-1970) was 0.8 μm. Roughness R _max of the surface of the conductive substrate after etching treatment in Comparative Example 3 and 4 (JIS B0601-1970) were respectively 5.0 and 4.6.

Next, these photoreceptors are used as a commercially available reversal developing type laser printer (PC-PR, manufactured by NEC Corporation).
1000), and the image characteristics under each environment were evaluated. As a result, the photoconductors A to H and L to N
In each case, 5 ° C / 10%, 25 ° C / 60%, 35 ° C /
Under any of the 85% environmental conditions, no moire-like shading was observed at all, and good images were obtained for both white and black background images. On the other hand, in the case of the photosensitive member I of Comparative Example 1, a moire-like unevenness in shading occurred on the entire surface of the halftone image. In the case of the photosensitive member J of Comparative Example-2, although the degree was lighter than that of the photosensitive member I, the same shading unevenness occurred. Comparative Example-
With the photoconductors K and O of Nos. 3 and 4, moiré-like shading did not occur, but a fogging phenomenon in which black spots appeared on the entire white background image occurred, and a good image was not obtained. This fog is considered to be a point where injection of charge from the conductive substrate side occurs at the time of charging of the photoreceptor because the surface is excessively roughened by etching, and this point has become a black point on an image. From the above results, it can be determined that the electrophotographic photoreceptor produced by the production method of the present invention has extremely excellent performance.

[0034]

According to the present invention, a conductive substrate having a moderately rough surface can be easily obtained by using the etching agent according to the present invention. Therefore, an electrophotographic photoreceptor using a conductive substrate subjected to a specific treatment according to the present invention is a problem in a normal photoreceptor even when used in an electrophotographic process using coherent light as a light source such as a laser printer. Moire-like image density unevenness does not occur at all, and a very good image can be obtained. Also, micro defects on the substrate surface, excessive etching,
An image defect caused by a stain or the like is almost completely removed by the processing of the present invention, so that a good image free from fog, black spots and white spots can be obtained.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-326357 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 5/00

Claims (9)

(57) [Claims] 1. A post-etching treatment with an etchant containing an alkali metal hydroxide and alkali metal and / or alkaline earth metal weak acid salts of, from aluminum or an aluminum alloy, characterized in facilities Succoth anodized For producing a conductive substrate for an electrophotographic photosensitive member comprising
Law. 2. An alkali metal hydroxide and an alkali.
To the sum of the weak salts of metals and / or alkaline earth metals
The proportion of the alkali metal hydroxide occupying is 60 to 90 weight
2. The electrophotograph according to claim 1, wherein the amount is%.
A method for producing a conductive substrate for a photoreceptor. 3. The etching process is performed by using aluminum ion
In an aqueous etchant solution containing 0.1 to 2% of
3. The electrophotographic photoreceptor according to claim 1, wherein:
For producing a conductive substrate for use. 4. The method according to claim 1, wherein the etching is performed on a surface of the conductive substrate.
Degree (Rmax) is 2-4 μm.
The electrophotographic feeling according to any one of claims 1 to 3,
A method for producing a conductive substrate for an optical body. 5. Surface roughness of a conductive substrate after anodizing treatment
(Rmax) is 0.2 to 1.5 μm.
5. The electrophotographic photosensitive device according to claim 1, wherein
A method for producing a conductive substrate for body. 6. The method according to claim 1, wherein the conductive substrate to be subjected to the etching treatment is a mirror.
Claims characterized by being surface-finished
Item 6. Conductivity for an electrophotographic photosensitive member according to any one of Items 1 to 5
A method for producing a functional substrate. 7. The product according to claim 1, wherein
A conductive substrate for an electrophotographic photosensitive member obtained by a manufacturing method. 8. An electrophotographic photosensitive member comprising the conductive substrate for an electrophotographic photosensitive member according to claim 7 , wherein at least a photoconductive layer is provided. 9. A contract for laser light.
An electrophotographic photoreceptor according to claim 8.