JP2763973B2 - Underlayer treatment method for laminated photoreceptor for electrophotography - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of treating an electrophotographic photosensitive member used for a photosensitive drum of an electrostatic copying machine or a laser beam printer, and more particularly to a method in which a photosensitive layer has a charge generating layer and a charge transporting layer. The present invention relates to a method for treating an underlayer of a laminated photoconductor comprising:

[0002] In this specification, the term aluminum is used to mean an aluminum alloy.

[0003]

2. Description of the Related Art In general, an electrophotographic photoreceptor is formed by coating a photosensitive layer on a conductive support made of aluminum. The photosensitive layer is replaced with an inorganic photoconductive material such as selenium. Organic photoconductors using organic materials (so-called OPC photoconductors) have come to be used because of their excellent film-forming properties, light weight, low cost, and the like.

Recently, in order to further improve the functions and characteristics of the organic photoreceptor, the photosensitive layer has recently been replaced with a charge generation layer (CG).
L) and a charge transport layer (CTL).

By the way, as the application of the electrophotographic photosensitive member to a laser beam printer or the like is expanded, the above-mentioned laminated photosensitive member is required to have high image reliability during reversal development. In particular, small-spot noise and image fogging when used in a high-temperature, high-humidity environment have become problems.

Therefore, as a laminated type photoreceptor which has eliminated such small black spot noise and fogging, an aluminum support is anodized, the barrier layer of the anodized film is 100 to 10000 angstroms, and the thickness of the porous layer is A proposal has been made to limit the height to 1 to 15 μm (Japanese Patent Laid-Open No. 63-116160). It has also been proposed to perform a pore-sealing treatment using an aqueous nickel acetate solution having a concentration of 1 to 15% by weight and a temperature of 50 to 80 ° C. after the anodizing treatment (Japanese Patent Laid-Open No. 63-116163).

[0007]

However, even when the thickness of the barrier layer or the porous layer of the anodic oxide film is limited as described above, or even when the sealing treatment is performed, the high temperature and high humidity The present inventors have found that in an environment, small black spot noise still occurs in an image, and the image quality cannot be sufficiently satisfied.

In addition, the present applicant first performs a sealing treatment with a high-temperature aqueous solution containing one or more selected from the group consisting of silicic acid, chromic acid, and their compounds after forming the anodic oxide film. (Japanese Patent Application Laid-Open No. 63-63).
No. 311261).

However, in this case, although the desired image characteristics can be improved, since a high-temperature aqueous solution is used, there is a risk that hydrates may be formed on the surface of the support, and high quality images can be obtained. There was a new problem that it could not be obtained stably.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a laminated photoreceptor for electrophotography capable of stably realizing high image quality by further suppressing small black spot noise.

[0011]

According to the present invention, there is provided a method for preparing an electrophotographic laminated photoreceptor having a charge generation layer and a charge transport layer on the surface of an aluminum support, the method comprising: After the support made of anodizing is anodized to form an anodic oxide film of 1 to 20 μm on the surface thereof, the chromate and F ⁻ at ₃ to 20 g / l in terms of CrO ₃ are obtained.
Temperature 1 containing 0.5 to 10 g / l of fluoride in conversion
The gist of the invention is to provide a method for treating the underlayer of an electrophotographic laminated photoreceptor, which is brought into contact with an aqueous solution at 5 to 50 ° C. for 10 seconds or more.

[0012] The type of aluminum constituting the support is not particularly limited.
An appropriate material may be selected from various commercially available aluminum materials in consideration of hardness and the like. However, preferably,
Al-Mg based alloys such as A5052, A6063, A
It is preferable to use an Al-Mg-Si alloy such as A6463. The reason for this is that when looking at the behavior of the intermetallic compound in anodic oxidation, A3003 and the like are insoluble and may remain in the film to impair the homogeneity.
063, AA6463 etc. elutes,
A homogeneous and sound film is obtained. Further, in the case of pure aluminum, the film is sound, but there is a problem that the mechanical strength as a part is inferior.

The anodic oxidation treatment is performed on the aluminum support in order to provide the anodic oxide film with adhesion between the photosensitive layer and the support and to improve charge injection prevention. The type of the anodic oxidation treatment is not particularly limited, and may be a sulfuric acid method using sulfuric acid as an electrolytic solution, an oxalic acid method using oxalic acid, or the like. In the present invention, the thickness of the anodic oxide film must be set to 1 to 20 μm. If the thickness is less than 1 μm, the adhesion to the photosensitive layer, the charge injection prevention property, and the like will be poor. On the other hand, even if the thickness exceeds 20 μm, an increase in these effects cannot be expected, but rather causes a decrease in productivity due to an increase in processing energy and processing time. It is particularly preferable to secure a thickness of about 5 to 10 μm. Before the anodizing treatment, if necessary, the aluminum support may be subjected to a pretreatment such as degreasing, washing with water or etching.

After the anodized aluminum support is subjected to a treatment such as water washing if necessary,
chromate and F of 3 to 20 g / l (liter) with and rO ₃ terms ^- is contacted with an aqueous solution containing as an essential component a fluoride of 0.5 to 10 g / l (liter) in terms of. The reason for using chromate as an essential component is as follows. That is, the chromate ions in the bath are reduced, precipitated as a slightly soluble chromium compound, and change to poorly soluble with time. Since this thin film has extremely good adhesion to the coating film, the binding property of the photosensitive layer is improved. Further, since it is hydrophobic, hardly soluble and stable, it does not adsorb moisture to alumite even under a high-temperature and high-humidity environment, can maintain a high charge injection prevention property, and can obtain an image without black spot noise. Because. For this purpose, the concentration of chromate in the aqueous solution must be ₃ to 20 g / l in terms of CrO3. When the amount is less than 3 g / l, the above effect is insufficient. On the other hand, when the amount exceeds 20 g / l, not only the effect of increasing the above effect is not particularly increased, but also the concentration of the liquid taken out becomes high, contaminating the washing water in the subsequent step, and the wastewater treatment. Will increase the load. The preferred content range of the chromate is ₅ to 15 g / l in terms of CrO3.

On the other hand, the reason why fluoride is used as an essential component is as follows. That is, fluorine ions are chemically adsorbed or chemically bonded to the wall portion in the active alumite pores. This is because the mediation of fluorine ions allows CrO ₃ to be easily deposited in the pores. However, fluoride F ^-
If the conversion is less than 0.5 g / l, the effect is poor.
When the concentration exceeds 0 g / l, the concentration of the liquid taken out also increases,
The post-process washing water is contaminated and the load of wastewater treatment is increased. Therefore, the content of fluoride in the aqueous solution, F ^- shall be the 0.5 to 10 g / l in terms of. Particularly preferably F ^- is in terms of 3 to 7 g / l.
The type of fluoride is not particularly limited,
As an example, an alkali fluoride salt, an alkali silicofluoride salt, an alkali titanium fluoride salt, an alkali borofluoride salt and the like can be mentioned.

Further, in the present invention, the temperature of the aqueous solution must be set to 15 to 50 ° C. If the liquid temperature is lower than 15 ° C., the promotion of adsorption of CrO ₃ becomes insufficient, causing black spot noise in an image. On the other hand, 50 ° C
It is presumed that a hydrated oxide of aluminum is formed at a temperature higher than the above, which impairs electrical properties such as charge injection prevention properties and also causes black spot noise. A particularly preferred liquid temperature is 30 to 40 ° C.

Further, the treatment time with the aqueous solution needs to be 10 seconds or more in order to perform necessary and sufficient adsorption of CrO ₃ . However, even if the treatment is performed for more than 40 minutes, the effect of adsorbing CrO ₃ is saturated and time is wasted. Therefore, the treatment time is preferably set to 40 minutes or less. It is particularly preferable to set the time to 3 to 10 minutes. The method of contacting the conductive support with the aqueous solution may be a shower method or the like,
An immersion method can be employed as a method that is reliable and suitable for mass production.

The conductive support having been subjected to the undercoat treatment as described above is subsequently coated with a laminated photosensitive layer having a charge generation layer and a charge transport layer. As the material of the photosensitive layer, a conventionally known material may be appropriately used. For example, the charge generation layer is obtained by dissolving a binder resin using an appropriate solvent, and dissolving various azo pigments, perylene pigments, phthalocyanine pigments, polycyclic quinone pigments, indico pigments,
A solution in which a pigment such as a quinacridone pigment is added in an amount of 10 to 200 parts by weight based on 100 parts by weight of a binder resin and dispersed by a method such as a ball mill, a vibration mill, a sand mill, and a roll mill has a thickness of about 0.1 to 1 μm. It may be formed by applying to the substrate. In addition, the charge transport layer is composed of an electron-donating substance composed of a derivative such as pyrazoline, triphenylmethane, oxadiazole, carbazole, hydrazone, styryl, imidazole, trinitrofluorenone, tetranitroxanthone, tetracyanoethylene, tetracyanoquinodidiene. It may be formed by dissolving a substance having a charge transporting property such as methane or the like in a resin having a film-forming property and applying it to 5 to 30 μm. Examples of the binder resin used for the charge generation layer and the charge transport layer include polyester, polycarbonate, polymethacrylate, polyvinyl butyral, silicone resin, epoxy resin, melamine resin, urethane resin, and polystyrene.

[0019]

The aluminum support on which an anodic oxide film having a thickness of 1 to 20 μm is formed by anodic oxidation treatment has a CrO ₃ equivalent of 3 μm.
~ 20g / l chromate and 0.5 ~ 10g in F-
It is presumed that by contacting with an aqueous solution containing 15 / l of fluoride at a temperature of 15 to 50 ° C for 10 seconds or more, CrO ₃ is adsorbed to the micropores of the anodized film while the formation of hydrated oxides is suppressed. This is presumed to be effective in preventing the occurrence of black spot noise in the image.

[0020]

According to the present invention, as described above, an aluminum support having an anodic oxidation treatment to form an anodic oxide film having a predetermined film thickness can be obtained by converting a chromate of ₃ to 20 g / l in terms of CrO ₃ and F- It is brought into contact with a low-temperature aqueous solution containing a fluoride of 0.5 to 10 g / l at a temperature of 15 to 50 ° C. for 10 seconds or more. In particular, even under a severe environment of high temperature and high humidity, black noise and fog can be suppressed, and the image quality can be stably improved. As a result, it can be made suitable as a photoconductor such as an electrostatic copying machine or a laser beam printer.

[0021]

Next, an embodiment of the present invention will be described.

Each aluminum alloy tube made of A3003, A5052 and A6063 was prepared and used as a support.

Each of the above supports was pretreated.
Pretreatment is degreasing (surfactant, 65 ° C. × 10 minutes), water washing (running water, 1 minute), etching (NaOH, 10 g / l,
30 ° C x 30 seconds), water washing (running water, 1 minute), neutralization (HNO
₃ , 13w / v%, normal temperature × 5 minutes), water washing (running water, 5 minutes)
Was carried out sequentially.

Next, a current density of 1 A / dm ² was obtained by using an aqueous solution of H ₂ SO ₄ : 14 w / v% sulfuric acid (solution temperature: 20 ° C.).
× Anodize under conditions of 25 minutes, thickness about 7μ
m of the anodic oxide film was formed.

Next, after washing with water (running water for 5 minutes) twice, A: a comparative product which is not treated, B: 95 ° C. in pure water
Comparative product immersed in × 10 minutes and sealed, C: Comparative product immersed in a 5 g / l aqueous solution of nickel acetate at 95 ° C. × 10 minutes and sealed, D: Chromic acid 10 g / l and sodium fluoride Four types of supports of the present invention were immersed in an aqueous solution containing 5 g / l at 30 ° C. for 5 minutes.

Next, the support was spray-washed with pure water and air-dried, and then a photosensitive layer having a charge generation layer and a charge transport layer on the support surface was formed as follows. That is, the CGL layer is prepared by diluting a metal-free phthalocyanine to 4% with tetrahydrofuran and forming a film having a thickness of about 0.5 μm.
m and dried and formed. Next, CT agent (hydrazone compound) and CT resin (polycarbonate)
Was dissolved in methylene chloride at a ratio of 1: 2 to give a film thickness of about 2
It was coated so as to have a thickness of 0 μm and dried to form a CTL layer.

The temperature and humidity of the various photoconductors obtained as described above were changed as shown in Table 1, and the initial surface potential (V0) was -7.
The occurrence of black spots on a blank portion of the image when the image was reverse developed at 50 V and a developing bias (Vb) of -500 V was examined. Table 1 shows the results.

[0028]

[Table 1]

As can be seen from Table 1, according to the present invention, it was confirmed that black spot noise when reversal development was performed even in a high-temperature and high-humidity environment could be suppressed.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03G 5/14 101

Claims (1)

(57) [Claims] 1. A method of treating a surface of an electrophotographic laminated photoreceptor having a charge generation layer and a charge transport layer on the surface of an aluminum support, the method comprising: After forming the anodized film ～20Myuemu, chromate and F of 3 to 20 g / l in CrO ₃ terms ^- to an aqueous solution of a temperature 15 to 50 ° C. containing fluorides 0.5 to 10 g / l in terms of An underlayer treatment method for a laminated photoconductor for electrophotography, wherein the substrate is contacted for at least 10 seconds.