JPH0784391A - Manufacture of support body for electrophotographic photoreceptor, and electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE:To provide an excellent method of manufacturing an electro- photographic receptor support body formed of an aluminum or aluminum alloy base and an anodic oxide film formed thereon so as to obtain an electrophotographic receptor of high image quality using this support body. CONSTITUTION:The surface of an aluminum alloy base 1a is subjected to degreasing-cleaning and anodic oxidation with a sulfuric solution at the solution temperature of about 18 deg.C-21 deg.C as electrolyte to form an anodic oxide film 1b, thus manufacturing a support body 1. photosensitive layer 2 with a charge generating layer 2a and a charge transport layer 2b laminated is formed on the support body l by application to prepare an electrophotographic photoreceptor. Or the surface of the aluminum alloy base 1a is subjected to degreasing-cleaning and anodic oxidation and further sealing using a nickel acetate solution at the solution temperature of about 60 deg.C-80 deg.C to form an anodic oxide film 1b with the Y-vlue being 20muS or less, thus manufacturing the support body 1, and the electrophotographic receptor is manufactured in the same way using this support body 1.

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 a support for an electrophotographic photosensitive member comprising an aluminum anodic oxide film formed on the surface of a conductive substrate made of aluminum or an aluminum alloy, and an organic material using the support. The present invention relates to an electrophotographic photoreceptor having a photosensitive layer made of a material.

[0002]

2. Description of the Related Art Although electrophotographic technology has been developed in the field of copying machines, it has recently been applied to devices other than copying machines such as laser printers, and the image quality is incomparable to that of conventional devices. , It is rapidly spreading due to its high speed and quietness. The photoconductors used in these electrophotographic devices are
A photosensitive layer is provided on the support. Recently, an organic material has been frequently used as a material for the photosensitive layer, and as a layer structure, as shown in FIG. 6, an electrophotographic image including a conductive substrate 11 and an undercoat layer 12 formed thereon. A function-separated laminated structure is generally formed by forming a photosensitive layer 2 in which a charge generation layer 2a made of an organic material and a charge transport layer 2b are sequentially laminated on a photoreceptor support 1.

As the conductive substrate 11, a substrate made of aluminum or aluminum alloy is usually used. As the undercoat layer 12, a case where a coating film of a resin material represented by polyamide is used, and a case where an anodized film formed by subjecting the surface of a substrate made of aluminum or an aluminum alloy to anodization treatment is used. However, the latter is generally superior in reliability under high temperature and high humidity environment.

When an aluminum anodic oxide film is used as the undercoat layer, an anodizing method using a sulfuric acid solution as an electrolytic solution is usually employed. That is, the surface of a substrate made of aluminum or aluminum alloy processed into a suitable shape and surface shape as a conductive substrate is degreased with a commercially available degreasing agent, washed with water, and then etched with an alkaline solution such as NaOH solution or K0H solution. Then, the surface is further degreased and cleaned, and then the sulfuric acid concentration is 160 g / liter to 2
Using a sulfuric acid solution of 00 g / liter as an electrolytic solution, the liquid temperature is about 15 ° C. to about 18 ° C. and the current density is 3 A / dm ^{2 to} 5 A / d.
Anodize at m ² for 15 to 25 minutes. In the subsequent sealing treatment, a nickel acetate solution is often used, which is about 40
A nickel acetate solution kept at a temperature in the range of 60 ° C. to about 60 ° C. is used to perform a sealing treatment for 5 minutes to 10 minutes to form an anodized film.

A coating solution containing an organic charge generating substance is formed on the anodic oxide film as the undercoat layer thus formed,
Alternatively, if necessary, a coating solution containing a resin binder is further applied to form a charge generation layer, and a coating solution containing an organic charge transporting substance is formed thereon, or a coating solution further containing a resin binder is formed if necessary. A liquid is applied to form a charge transport layer, and a photoreceptor is obtained.

[0006]

However, in the case of a photoreceptor using a support having an anodized film formed on a conductive substrate made of aluminum or an aluminum alloy as described above, anodizing conditions and sealing treatment are required. Depending on the conditions, there is a problem that charge injection from the film into the charge generation layer occurs, the potential holding performance of the photoconductor is deteriorated, and "ground fog" is significantly generated especially in a high humidity environment. A charge generation layer is formed by coating on the anodic oxide film, but the charge generation layer is required to be a thin film having a thickness of the submicron order, and uneven coating may occur due to variations in surface properties of the anodic oxide film. However, there is a problem that it causes "density unevenness" of the obtained image.

The present invention has been made in view of the above points, and a anodic oxide film having a suitable electric resistance and a uniform surface property is formed on a conductive substrate made of aluminum or an aluminum alloy. It is an object of the present invention to provide a method for efficiently producing a good electrophotographic photosensitive member support which is formed as a pulling layer and does not cause the above-mentioned "background fog" and "density unevenness". Further, another object of the present invention is to obtain an electrophotographic photosensitive member which can obtain a high quality image even in a high humidity environment by using the support thus obtained.

[0008]

According to the present invention, the above object is to electrolyze a sulfuric acid solution in which the surface of a conductive substrate made of aluminum or an aluminum alloy is kept within a temperature range of about 18 ° C to about 21 ° C. This can be solved by anodizing as a liquid to form an anodized film to form a support for an electrophotographic photoreceptor, and using the support to produce an electrophotographic photoreceptor.

Further, the above problem is that the surface of a conductive substrate made of aluminum or an aluminum alloy is anodized and subsequently sealed with a nickel acetate solution held in a temperature range of about 60 ° C. to about 80 ° C. This can be solved by performing a treatment to form an anodized film having an admittance value of 20 μS or less as a support and using the support to prepare a photoreceptor.

[0010]

In the present invention, anodic oxidation is performed at a liquid temperature of about 18
Sulfuric acid solution kept in the temperature range of ℃ to about 21 ℃ is used as the electrolytic solution. Conventionally, the liquid temperature is about 16 ° C. or lower. This is because the lower the liquid temperature, the higher the surface hardness and the better the corrosion resistance of the film, which was suitable as a protective film. However, in the case of a support for a photoreceptor, the present inventor has a property that the potential holding performance is poor in a support having a film formed at a low liquid temperature, and the potential holding performance is improved as it is formed at a high liquid temperature. It was found that it is preferable to set the liquid temperature to at least about 18 ° C. or higher. On the other hand, in order for the anodic oxidation to be performed well, it is necessary that the electrolytic solution contains dissolved aluminum, and it is desirable that 1 g / liter to 10 g / liter of aluminum is dissolved, and 3 g / liter to A range of 7 g / liter is more desirable. If it is contained in a large amount exceeding 10 g / liter, aluminum may adhere to the surface of the coating, which is not preferable. However, when the liquid temperature rises to about 22 ° C. or higher, the amount of aluminum dissolved in the electrolytic solution increases during anodic oxidation, and the electrolytic solution is frequently used to prevent the amount of dissolved aluminum from exceeding 10 g / liter. A new replacement is required, which causes a problem that process control becomes difficult. By setting the liquid temperature within the range of about 18 ° C. to about 21 ° C., such a problem can be solved. The concentration of sulfuric acid in the electrolyte is 1
A range of 60 g / liter to 200 g / liter is preferred.

The sealing treatment is carried out at a liquid temperature of about 60 ° C. to about 8 ° C.
It is carried out using a nickel acetate solution kept in the range of 0 ° C. When the liquid temperature exceeds about 60 ° C, the admittance value indicating the degree of sealing is 20 μS or less, which is a good sealing degree.
By using such a support, it is possible to obtain a photoreceptor having high potential holding performance. Moreover, the surface of the anodized film becomes more uniform as the sealing treatment is performed at a higher liquid temperature, and by using such a support, it is possible to obtain a photoreceptor having an image with less "uneven density". On the other hand, if the temperature becomes too high, process control and liquid control become difficult, so the liquid temperature is about 60 ° C.
To about 80 ° C. The sealing treatment liquid preferably has a nickel acetate concentration of about 6 g / liter, and the treatment time is preferably 5 minutes to 10 minutes, more preferably 8 minutes to 1 minute.
0 minutes.

[0012]

Embodiments of the present invention will be described below.
FIG. 1 is a schematic cross-sectional view of an embodiment of a photoconductor according to the present invention, which is an aluminum alloy substrate 1a as a conductive substrate.
A charge generation layer 2a made of a coating film of an organic material is formed on a support 1 on which an anodized film 1b as an undercoat layer is provided.
The photosensitive layer 2 in which the charge transport layer 2b is sequentially laminated is provided.

Example 1 A conductive substrate made of an aluminum alloy (JIS 6063 material) was coated with a degreasing agent (Nihon Parker Rising Co., Ltd.).
Manufactured by Fine Cleaner 315), degreasing is performed at a liquid temperature of 50 ° C., and washing is performed with water to remove the degreasing agent. Subsequently, the surface was cleaned by further performing degreasing cleaning by etching using a nitric acid solution having a concentration of 15% and then cleaning with pure water. This substrate is anodized. Electrolyte has a concentration of 1
A 50 g / liter sulfuric acid solution was used, and the amount of dissolved aluminum in the electrolytic solution was 3 g / liter to 7 g / liter. Approximately 5 A / d by changing the liquid temperature to 15 ℃, 20 ℃, 22 ℃
Anodizing treatment was performed at m ² for 24 minutes, and then washed with pure water.
Subsequently, a nickel acetate solution having a concentration of 6 g / liter was used for sealing treatment at a liquid temperature of 70 ° C. for 8.5 minutes, washed with pure water, and dried to obtain a support for a photoreceptor.

On each of the thus obtained three types of supports, a coating solution prepared by dispersing and dissolving X-type metal-free phthalocyanine and vinyl chloride vinyl acetate copolymer in a ratio of 1: 1 was applied. Forming a charge generation layer having a thickness of 0.2 μm,
Subsequently, a coating solution in which a polycarbonate resin and a hydrazone-based material were dissolved at a ratio of 1: 1 was applied to form a charge transport layer having a film thickness of 20 μm, and the photoconductor having the configuration shown in FIG. 1 was produced.

For these photoreceptors, the potential holding ratio V _K5 (%) after 5 seconds of charging and the half-attenuated exposure amount E _1/2 (μJ / cm ² ) when exposed to monochromatic light having a wavelength of 780 nm were measured. . FIG. 2 shows the relationship between V _K5 and E _1/2 with the liquid temperature at the time of anodic oxidation as a parameter. As seen in Figure 2,
When the half-decay exposure dose E _1/2 is the same, the higher the liquid temperature during anodic oxidation, the higher the potential holding ratio. When images were formed on each of these photoconductors, the "background fog" decreased as the liquid temperature during anodic oxidation increased.

However, the amount of aluminum dissolved from the substrate increases as the liquid temperature during anodic oxidation increases, and the amount of dissolved aluminum in the electrolytic solution increases with the treatment time to exceed 10 g / liter, and The problem occurs that aluminum is precipitated. Liquid temperature 2
At 2 ° C., the amount of aluminum dissolved was large, and in order to keep the amount of dissolved aluminum below 10 g / liter, the electrolytic solution had to be refreshed frequently, making process control difficult.

From the above results, the liquid temperature during anodic oxidation is about 1
It can be seen that the preferred range is from 8 ° C to about 21 ° C. Example 2 A degreasing agent (manufactured by Okuno Chemical Industries Co., Ltd .; Alclean 1) was prepared by using a conductive substrate made of an aluminum alloy (JIS 6063 material).
60) is used for degreasing and washing with water to remove the degreasing agent. Subsequently, the surface was cleaned by further performing degreasing cleaning by etching using a nitric acid solution having a concentration of 15% and then cleaning with pure water. This substrate was anodized in the same manner as in Example 1 except that the liquid temperature for anodization in Example 1 was kept constant at 20 ° C. Then, using a nickel acetate solution having a concentration of 6 g / liter, the liquid temperature was 40 ° C., 50
The sealing treatment is performed for 8.5 minutes by changing the temperature to 60 ° C., 60 ° C., 70 ° C., 80 ° C., washed with pure water, and dried to obtain a support for five types of photoreceptors having different sealing treatment liquid temperatures. It was made.

A charge generation layer and a charge transport layer were formed on each of the five types of supports thus obtained in the same manner as in Example 1 to prepare a photoreceptor having the structure shown in FIG. did. With respect to these photoconductors, the potential holding ratio V _K5 ( ₅ %) after charging for 5 seconds, the half-attenuation exposure amount E _1/2 (μJ / cm ² ) when exposed to monochromatic light having a wavelength of 780 nm, and the wavelength of 7
The residual potential V _r (V) when monochromatic light of 80 nm was exposed to 10 μJ / cm ² was measured. Fig. 3 shows the relationship between V _K5 and E _1/2 with the liquid temperature during the sealing process as a parameter.
FIG. 4 shows the relationship between V _r and E _1/2 .

As shown in FIGS. 3 and 4, when the half-attenuated exposure dose E _1/2 is the same, the higher the liquid temperature during the sealing treatment, the higher the potential holding ratio V _K5 and the residual potential V 2. _{r is} also low. When images were printed on these photoconductors, the higher the liquid temperature at the time of the sealing treatment, the more the “background fog” was reduced. Further, when the occurrence rate of "density unevenness" defects was examined for the images obtained with these photoconductors, the results shown in Table 1 were obtained, and the higher the liquid temperature during the sealing treatment, the lower the occurrence rate of defects. I knew that. Table 1 also shows the evaluation results of the variation in the L value indicating the color difference (brightness) of the color on the surface of the photoconductor of each photoconductor. The surface of the anodic oxide film becomes more uniform and less uneven as the temperature of the sealing treatment liquid becomes higher, and the photosensitive layer is coated and formed more evenly.
Σ indicating the variation of the values is small. There is a good agreement between the variation in the L value and the occurrence rate of the "density unevenness" defect in the image.

[0020]

[Table 1]

Further, the degree of sealing of the anodic oxide coatings of these supports was evaluated by a non-destructive alumite sealing degree tester ANOTEST manufactured by Fischer. The result is shown in FIG.
FIG. 5A is a diagram showing the relationship between the admittance Y of the anodized film and the temperature of the sealing treatment liquid, and FIG. 5B is the loss factor d of the anodized film (the resistance R and the capacitance X _c of the film. ratio)
It is a diagram showing the relationship between the sealing treatment liquid temperature and. In FIG. 5, ◯ indicates a value at 2 minutes after injection of the test solution, and ● indicates a value at 80 minutes after injection of the test solution.

From FIG. 5 (a), the admittance Y is 20 μS or less when the temperature of the sealing solution is 60 ° C. or higher, and shows a good degree of sealing with little change due to the elapsed time after injection of the test solution. Also, the loss factor d in FIG. 5B is small when the temperature of the sealing treatment liquid is 60 ° C. or higher, which shows that the sealing degree is also good. Although aluminum alloy 6063 is used as the conductive substrate in each of the above-described examples, the conductive substrate is not limited to this, and may be made of pure aluminum, 6000 series alloy, 3000 series alloy, etc. It can be appropriately selected and used in consideration.

In the degreasing cleaning performed before the anodic oxidation treatment, nitric acid etching is performed instead of the usual alkali etching of KOH or NaOH.
As a result, the occurrence of etch pits on the surface of the conductive substrate was reduced, and a photoreceptor having an image with few "black spots" defects was obtained.

[0024]

According to the present invention, the surface of a substrate made of aluminum or an aluminum alloy is anodized by using a sulfuric acid solution held in a temperature range of about 18 ° C. to about 21 ° C. as an electrolytic solution. Alternatively, the surface of a conductive substrate made of aluminum or an aluminum alloy is anodized, and subsequently, a sealing treatment is performed by using a nickel acetate solution held in a temperature range of about 60 ° C to about 80 ° C to obtain a sealing degree. An anodic oxide film having an admittance value of 20 μS or less is formed. By adopting such a manufacturing method, it is possible to form, on the conductive substrate made of aluminum or an aluminum alloy, a uniform anodic oxide film having an appropriate electric resistance and a surface texture as an undercoat layer. By forming a charge generating layer and a charge transporting layer made of an organic material on the support thus obtained in order to form a photosensitive layer, the occurrence of "background fog" is reduced even in a high humidity environment. In addition, it is possible to obtain an electrophotographic photosensitive member that is free from the occurrence of "density unevenness" and that can obtain an image of excellent image quality.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an embodiment of a photoconductor according to the present invention.

FIG. 2 is a diagram showing a relationship between a potential holding ratio and a semi-attenuated exposure amount with an anodizing solution temperature as a parameter.

FIG. 3 is a diagram showing a relationship between a potential holding ratio and a half-attenuated exposure amount with a sealing treatment liquid temperature as a parameter.

FIG. 4 is a diagram showing the relationship between the residual potential and the half-attenuated exposure dose with the temperature of the sealing liquid as a parameter.

FIG. 5 is a diagram showing the relationship between the temperature of the sealing treatment liquid and the degree of sealing,
FIG. 5 (a) is a diagram showing the relationship between the temperature of the sealing treatment liquid and the Y value of the anodized film, and FIG. 5 (b) is a line showing the relationship between the temperature of the sealing treatment liquid and the d value of the anodized film. Figure

FIG. 6 is a schematic sectional view of an example of a conventional photoconductor.

[Explanation of symbols]

 1 Support 1a Aluminum Alloy Substrate 1b Anodized Layer 2 Photosensitive Layer 2a Charge Generation Layer 2b Charge Transport Layer 11 Conductive Substrate 12 Undercoat Layer

Claims (3)

[Claims] 1. A method for forming an aluminum anodic oxide film by anodizing a sulfuric acid solution in which the surface of a conductive substrate made of aluminum or an aluminum alloy is kept in a temperature range of about 18 ° C. to about 21 ° C. as an electrolytic solution. A method for producing a characteristic electrophotographic photoreceptor support. 2. A surface of a conductive substrate made of aluminum or an aluminum alloy is anodized, and subsequently, a sealing treatment is performed by using a nickel acetate solution kept in a temperature range of about 60 ° C. to about 80 ° C. A method for producing a support for an electrophotographic photosensitive member, which comprises forming an anodized film having an admittance value showing a porosity of 20 μS or less. 3. An electrophotographic photosensitive member using the support produced by the method according to claim 1.