JP2668985B2 - Electrophotographic photoreceptor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor having a photosensitive layer formed on a substrate having been subjected to a surface roughening treatment. The present invention relates to an electrophotographic photosensitive member suitable for a system electrophotographic printer.

2. Description of the Related Art Conventionally, a line-scanning electrophotographic printer using a laser beam uses a gas laser having a relatively short wavelength such as a helium-cadmium laser, an argon laser, and a helium-neon laser as a laser beam.
In addition, as the electrophotographic photoreceptor used therefor, a CdS-binder type photosensitive layer forming a thick photosensitive layer, a charge transfer complex (IBM Journal of the Research and Development, 197
Since January, January, p.75-p.89), the laser beam did not cause multiple reflections in the photosensitive layer, so that an image of interference fringes appeared in actual image formation. There was no.

However, in recent years, semiconductor lasers have been used in place of the above-described gas lasers in order to design the apparatus to be smaller and lower in cost.
This semiconductor laser generally has an oscillation wavelength in a long wavelength region of 750 nm or more. Therefore, an electrophotographic photosensitive member having high sensitivity characteristics in a long wavelength region is required. The body has been developed.

Long-wavelength light known so far (for example, 600 nm or more)
Examples of the photoreceptor having photosensitivity include a photosensitive layer containing a phthalocyanine pigment such as copper phthalocyanine and aluminum chloride phthalocyanine, and in particular, a laminated electrophotographic photosensitive layer having a photosensitive layer having a laminated structure of a charge generation layer and a charge transport layer. A body or an electrophotographic photoreceptor using a selenium-tellurium film is known.

When a photoreceptor having such long wavelength light sensitivity is attached to a laser beam scanning type electrophotographic printer and subjected to laser beam exposure, interference fringe patterns appear on the formed toner image, and a good It has a drawback that a reproduced image cannot be formed. One of the reasons for this is, for example,
The long-wavelength laser is not completely absorbed in the photosensitive layer, and the transparent light is specularly reflected on the surface of the substrate, so that multiple reflections of the laser beam are generated in the photosensitive layer, which is reflected between the reflected light on the surface of the photosensitive layer. It is said that it causes interference in.

As a method for solving this drawback, there has been disclosed in JP
58-162975, 60-79360, 60-112049, 61
-42663, as described in JP-A-62-186270, etc., a method of roughening the surface of a conductive substrate used in an electrophotographic photoreceptor by an anodizing method or a buffing method, or JP-A-58-17105, 59-158 and 59-204048.
As described in JP-A-60-86550 and the like, it has been proposed to eliminate multiple reflections occurring in the photosensitive layer by a method using a light absorbing layer or an antireflection layer between the photosensitive layer and the substrate. ing.

Problems to be Solved by the Invention However, the above-mentioned conventionally proposed method cannot completely eliminate the interference fringe pattern which appears during image formation as a practical problem. In particular, in the case of the method of roughening the surface of the conductive substrate, it is difficult to form a rough surface having a uniform roughness, and a portion having a relatively large roughness may be formed at a certain ratio. For this reason, the large roughness portion acts as a carrier injection portion into the photosensitive layer, and causes white spots (or appears as spots when the reversal development method is used) during image formation, Not the preferred method. That is, if only attention is paid to preventing the occurrence of interference fringe patterns, there are various solutions, but it is extremely difficult to prevent black spots and white spots from appearing on the image simultaneously with the occurrence of interference fringe patterns. However, it was one of the major problems that cannot be realized by the above method. Moreover, in the case of the method of roughening the surface of the conductive substrate, it is difficult to manufacture a conductive substrate having a uniform rough surface in the same lot in manufacturing, and there are many points to be improved. .

Incidentally, JP-A-51-58954 discloses that a conductive substrate is roughened by honing.
No. 8553 discloses that the surface is roughened by a specific surface treatment material, but these are intended to improve the adhesion between the substrate and the photosensitive layer,
The appearance of the interference fringe pattern cannot be prevented.

In addition, the method using a light absorbing layer or an antireflection layer also has the drawbacks that the interference fringe pattern cannot be sufficiently eliminated and that the production cost increases.

The present invention has been made in view of the above-described problems in the related art.

Therefore, it is an object of the present invention to provide a novel electrophotographic photosensitive member and a method for manufacturing the same, which solves the above-mentioned problems in the conventional technique.

Further, an object of the present invention is to provide an electrophotographic photoreceptor which simultaneously and completely eliminates the appearance of interference fringe patterns appearing during image formation and white spots during image formation or black spots during reversal development, and a method of manufacturing the same. To provide.

Another object of the present invention is to provide a method for treating an electrophotographic photosensitive substrate.

Means for Solving the Problems Since the interference of light is caused by the regular reflection of the laser beam light on the surface of the substrate, it is only necessary to eliminate this reflection. A method of applying paint to prevent reflection can be considered. However, in that case, since the surface of the black coating film was glossy, the light was also specularly reflected and the interference could not be completely prevented. Therefore, the inventors of the present invention focused on effectively diffusely reflecting light to prevent interference.

As a result of the study, the present inventors roughened the surface of the substrate to the extent necessary to eliminate the interference fringe pattern appearing at the time of image formation. In the case of using the reflection development method, the number of black spots increases), resulting in a very poor copy. However, when the surface of the substrate is roughened using a silicon carbide abrasive, It has been found that the above-mentioned white spots or black spots do not occur during image formation, and at the same time, the appearance of interference fringes can be prevented, and the present invention has been completed.

That is, the electrophotographic photoreceptor of the present invention has a cumulative percentage (%).
Has a 50% particle size of 5 to 55 μm and a bulk specific gravity of 0.75 to
The photosensitive layer is formed on a substrate that has been subjected to wet honing treatment at a spraying speed of 20 to 75 m / sec using a silicon carbide-based abrasive at 1.6 g / cc.

The method for treating an electrophotographic photosensitive substrate of the present invention has a 50% particle diameter of 5 to 55 μm in terms of cumulative percentage (%) and a bulk specific gravity of
A wet honing process is performed by spraying a silicon carbide-based abrasive at 0.75 to 1.6 g / cc onto the substrate surface at a spray speed of 20 to 75 m / sec.

 Hereinafter, the present invention will be described in detail.

In the electrophotographic photosensitive member of the present invention, as the substrate, a drum, sheet or the like of aluminum, copper, iron, nickel, zinc or the like, metal or alloy is used.

In the present invention, the surfaces of these substrates are roughened, but the roughening is performed by a wet honing treatment.
As a method of roughening the surface of the substrate, a method of adjusting the accuracy of surface cutting, a method of pressing a rotating grindstone, an anodizing method, an etching method, a sandpaper processing method, a wet honing method, a sandblasting method, Buffing methods and the like can be mentioned. Among these methods, the wet honing method has a short working time, is simple in work, easily obtains a desired surface roughness, and has stability. This is the preferred method for some reasons. In the present invention, a uniform pear surface is formed by using the wet honing method, using an abrasive having specific properties, and performing spray processing at a specific spray speed.

The wet honing treatment is a method in which a powdered abrasive is suspended in a liquid such as water and sprayed on a substrate surface at a high speed to roughen the surface. In this case, the surface roughness is determined by a spray pressure,
Speed, quantity when polishing, type, shape, size, hardness, specific gravity,
And the suspension concentration. In the present invention, in the above-mentioned wet honing treatment, the abrasive has a 50% particle size of 5 to 55 μm in terms of a cumulative percentage (%) as an abrasive.
And a silicon carbide type material having a bulk specific gravity of 0.75 to 1.6 g / cc is used.

It is necessary that the silicon carbide-based abrasive has a 50% particle size (according to the method of JIS R6002) of 5 to 55 μm in terms of a cumulative percentage (%) as a particle size. The above particle size is 5 μm
If it is smaller than 50 μm, it will not be possible to obtain a sufficient matte surface.
If it is larger than m, the surface of the substrate is ground more than necessary, resulting in an image quality defect.

Furthermore, the silicon carbide abrasive has a bulk specific gravity (JIS R61260
It is necessary to be 0.75 to 1.6 g / cc. When the bulk specific gravity is lower than 0.75 g / cc, the ratio of the major axis to the minor axis of the abrasive particles becomes large, the ratio of the acicular particles becomes too large, and the mechanical strength of the abrasive becomes low, and the initial wet honing treatment is performed. Is not stable, and the amount of the adhered or rushed abrasive on the surface of the substrate increases, so that image defects are likely to occur. Also, when the bulk specific gravity becomes larger than 1.6 g / cc,
Not enough satin is obtained, and the surface tends to have a high glossiness.

The silicon carbide-based abrasive is mainly composed of SiC, and two types, a green one and a black to gray one, are commercially available. In the present invention, any of them is suitable. Can be used for

As abrasives used in the wet honing treatment, small balls or crushed pieces such as cast steel, cast iron, and glass beads may be used. However, if wet honing treatment is performed using cast steel or cast iron, these are used as base materials. It is not preferable because it easily remains on the surface as an impurity, and becomes an injection site from the substrate, resulting in an image quality defect. Also, if you use glass beads,
Since the glass beads have a shape that is extremely close to a true sphere, the recesses on the surface after the treatment have a crater-like roundness. For this reason, the surface after the treatment becomes a semi-gloss smooth surface, and even if it has the same surface roughness, the glossiness is high and an interference fringe pattern easily occurs, which is not preferable.

In the present invention, it is necessary to use a silicon carbide type abrasive as described above as a polishing agent, and to spray the abrasive at a spraying speed of 20 to 75 m / sec on the substrate surface to roughen the surface. Spraying speed is defined by the distance between the injection spray gun and the substrate surface, and compressed air pressure, nozzle diameter, etc., but if the spraying speed is lower than 20 m / sec,
If not enough pear ground can be obtained, and if it is higher than 75 m / sec, unevenness occurs in the pear ground microscopically as described above,
A uniform matte surface cannot be obtained, and white spots and black spots appear on the image.

An undercoat layer is optionally provided on the substrate roughened as described above, and a photosensitive layer is formed thereon.

The undercoat layer is formed using a known resin. The thickness of the undercoat layer is preferably set in the range of 0.05 μm to 10 μm, particularly 0.1 μm to 2 μm.

A photosensitive layer is formed on the undercoat layer. When the photosensitive layer has a laminated structure of a charge generation layer and a charge transport layer, any of them may be provided on the undercoat layer.

The charge generation layer is obtained by dispersing a charge generation material in a binder resin, and a known charge generation material is used.
For example, azo dyes such as chlorodiane blue, anthantrone, quinone pigments such as pyrenequinone, quinocyanine pigments, perylene pigments, perinone pigments, indigo pigments, bisbenzimidazole pigments, copper phthalocyanines, phthalocyanine pigments such as vanadyl phthalocyanine, azulhenium salts, square Lithium pigments, quinacridone pigments and the like can be used.

As the binder resin of the charge generation layer, polystyrene resin,
Known materials such as polyvinyl acetal resin, acrylic resin, methacrylic resin, vinyl acetate resin, polyester resin, polyarylate resin, polycarbonate resin, and phenol resin are used.

The charge generation layer is formed by including a charge generation material in a solution of these binder resins and applying it on the undercoat layer. As the solvent used for dispersion, methanol, ethanol, n-propanol, n-butanol, benzine alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, dioxane, tetrahydrofuran, methylene chloride, chloroform and the like are usually used. Organic solvents are used.

The thickness of the charge generation layer is generally 0.1 to 5 μm, preferably
0.2 to 2.0 μm is suitable.

The charge transport layer is obtained by dispersing a charge transport material in a binder resin.Examples of the charge transport material include polycyclic aromatic compounds such as anthracene, pyrene, and phenanthrene, or indole, carbazole, and imidazole. And the like, a compound having a nitrogen-containing heterocycle, a pyrazoline compound, a hydrazone compound, a triphenylmethane compound, a triphenylamine compound, an enamine compound, a stilbene compound, and the like. Further, as the binder resin, any resin may be used as long as it has a film-forming property, for example, polyester, polysulfone, polycarbonate,
Polymethyl methacrylate or the like is used.

The charge transport layer has a thickness of 5 μm obtained by dissolving these binder resins in a solvent and adding the above charge transport material to the resulting solution.
It is formed by coating so as to have a thickness of m to 30 μm. Examples of the solvent include aromatic hydrocarbons such as benzene, toluene, and xylene; ketones such as acetone and 2-butanone; halogenated hydrocarbons such as methylene chloride, monochlorobenzene, and chloroform; and commonly used organic solvents such as tetrahydrofuran and ethyl ether. A solvent can be used.

Examples Hereinafter, the present invention will be described with reference to examples.

Examples 1 to 4 and Comparative Examples 1 to 9 An aluminum pipe having a thickness of 1 mm × 40 mmφ × 310 mm was prepared, and the aluminum pipe was subjected to a cutting process using a mirror lathe using a diamond bite to finish the surface to a smooth surface of Ra0.04 μm. . The aluminum pipe was roughened by the liquid honing device shown in FIG. In FIG. 1, 1 is a substrate, 2 is a pump, 3 is a gun, 4 is an air introducing pipe, and 5 is a processing container. Liquid honing is the first
10 kg of the abrasive shown in the table is suspended in water 40, and while being pumped at a flow rate of 6 / min to the gun 3 by the pump 2, the aluminum pipe is sprayed at a predetermined compressed air pressure at the spraying speed shown in the table 1. Sprayed. The gun is moved at 40 cm / min in the axial direction of the aluminum pipe, while the aluminum pipe
It was rotated at 100 rpm.

The abrasives used and the corresponding commercial products were as follows.

Example 1 Green Densic (GC # 400) manufactured by Showa Denko KK

Example 2 Showa Denko KK: Green Densic (GC # 1500).

Example 3 Showa Denko KK: Densic (C # 280).

Example 4 Densic (C # 700) manufactured by Showa Denko KK

Comparative Example 1 Green Densic (GC # 4000) manufactured by Showa Denko KK

Comparative Example 2 Green Densic (GC # 240) manufactured by Showa Denko KK

Comparative Example 3 Showa Denko KK: Green Densic (GC # 240) was adjusted to have a 50% particle size of 52.5 μm in percentage.

Comparative Example 4 The composition was the same as that of the abrasive of Comparative Example 1, but the average particle size was 8 μm.
Abrasive with m and bulk specific gravity of 0.69 g / cc.

Comparative Examples 5 and 6 The same abrasive as in Example 1.

Comparative Example 7 An abrasive mainly composed of molten zircon.

Comparative Example 8 An abrasive containing nitrided steel as a main component.

Comparative Example 9 Glass beads. (Fuji Bright, manufactured by Fuji Seiki Seisakusho) A methanol / butanol solution of a copolymerized nylon resin (CM8000, manufactured by Toray Industries, Inc.) was applied to the aluminum pipes subjected to the wet honing treatment as described above using a ring applicator. The coating was applied to form an undercoat layer having a thickness of 0.7 μm as a barrier layer.

Next, 3 parts of vanadyl phthalocyanine were dispersed in 70 parts of a 10% cyclohexanone solution of a polyester resin (PE100, manufactured by Goodyear Chemical Company). The dispersion operation was performed by using a 10 mmφ ball and mixing the mixture in a ball mill for 2 hours. To this, 10 parts of 2-butanone was added to prepare a coating solution, which was coated on the barrier layer with a ring coating machine,
A charge generation layer having a thickness of 0.4 μm was formed.

A charge transport layer was formed on the formed charge generation layer. That is, N, N'-diphenyl-N, N'-bis (3-methylphenyl)-[1,1-biphenyl] -4,4'-diamine (4 parts) is used as a charge transport material, and together with 6 parts of a polycarbonate Z resin. It was dissolved in 40 parts of monochlorobenzene and the resulting solution was applied by a dip coating device at a pulling rate of 11 cm / min. After drying at 110 ° C. for 1 hour, a charge transport layer having a thickness of 20 μm was formed to obtain an electrophotographic photosensitive member.

The obtained electrophotographic photoreceptor was attached to a laser printer (LBP) having a dot density of 400 dpi. When the output image of this LBP was examined, the results shown in Table 1 were obtained. That is, in the case of Examples 1 to 4, interference fringe patterns and white spots,
No image defects such as black spots were found. Also, image 2000
No abnormality occurred even when the output test of the sheets was performed.

On the other hand, in the case of the comparative example, the following results were obtained. That is, in the case of Comparative Example 1, since the cumulative percentage particle size was 50% small, a sufficient pear surface could not be obtained, and an interference fringe pattern occurred in the image.

In the case of Comparative Example 2, although no interference fringe pattern occurred in the image, various image defects (black spots, white spots, spot defects) occurred.

In the case of Comparative Example 3, however, the satin surface could not be obtained because of the high bulk specific gravity, and an image defect occurred.

In the case of Comparative Example 4, the life of the abrasive was short, and not only the initial image but also the continuous wet honing treatment was performed.
Furthermore, an interference fringe pattern was generated.

 In the case of Comparative Example 5, an interference fringe pattern was generated on the image.

In the case of Comparative Example 6, no interference fringe pattern was generated,
Many black spots appeared on the image.

In the case of Comparative Examples 7 and 8, although no interference fringe pattern was generated in the image, many image defects (black spots, white spots, spot defects) were generated.

In the case of Comparative Example 9, sufficient satin was not obtained on the surface of the substrate, and an interference fringe pattern was generated.

Effect of the Invention In the present invention, since the surface of the substrate is roughened by wet honing as described above, the average value of the surface roughness is sufficiently large on the surface of the substrate, and the distribution of the surface roughness is large. A uniform matte surface is formed having a surface condition with a small width. Therefore, when an electrophotographic photoreceptor formed using this substrate is subjected to image formation by laser beam light such as a semiconductor laser, interference fringe patterns and black spots,
A good image is formed without image defects such as white spots. Therefore, the electrophotographic photosensitive member of the present invention is suitable for an electrophotographic copying apparatus using a laser beam, in particular, an electrophotographic printer of a line scanning type with a laser beam.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a wet honing device used in the present invention. 1 ... Substrate, 2 ... Pump, 3 ... Gun, 4 ... Air introduction pipe, 5 ... Processing container.

Claims (3)

(57) [Claims] 1. A 50% particle size by cumulative percentage (%) is 5 to 55.
μm, and a photosensitive layer was formed on a substrate subjected to wet honing at a spraying speed of 20 to 75 m / sec using a silicon carbide-based abrasive having a bulk specific gravity of 0.75 to 1.6 g / cc. An electrophotographic photosensitive member. 2. The 50% particle size by cumulative percentage (%) is 5 to 55.
An electrophotographic photoreceptor characterized in that a silicon carbide type abrasive having a bulk specific gravity of 0.75 to 1.6 g / cc is sprayed onto a substrate surface at a spraying speed of 20 to 75 m / sec to perform a wet honing treatment. A method for treating a body substrate. 3. A 50% particle size by cumulative percentage (%) is 5 to 55.
μm and a bulk specific gravity of 0.75 to 1.6 g / cc, and a silicon carbide-based abrasive is sprayed onto the surface of the substrate at a spraying rate of 20 to 75 m / sec to perform wet honing treatment on the roughened substrate surface. A method for producing an electrophotographic photoreceptor, which comprises applying a photosensitive layer coating solution to form a photosensitive layer.