JPH07325405A - Cleaning method of substrate for photoreceptor drum - Google Patents

Abstract

PURPOSE:To manufacture a photoreceptor drum hardly having a discharge breakdown by grinding the surface of a cylinder made of stainless steel and then, simultaneously cleaning the surface and inner periphery with brushes. CONSTITUTION:In the photoreceptor drum substrate 1, first the surface of the cylinder made of the stainless steel is ground to obtain <=2.0mum surface roughness Rmax. However, for preventing an interference fringe pattern from being generated at the time of irradiating the surface with laser light, it is preferable that the Rmax is >=0.1mum. A surface cleaning brush 21 attached to a brush supporting body 22 and an inner periphery cleaning brush 23 attached to a brush supporting body 24 are rotated while the photoreceptor drum substrate 1 is rotated, to simultaneously clean the surface and inner periphery. At the time of cleaning, washing water 25 is jetted to the surface of the substrate 1. The washing water 25 is supplied to a nozzle 26 from the outside through piping 27. Thus, not only oil but also ground powder can be removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning the surface and inner surface of a stainless steel photosensitive drum substrate for photosensitive drums.

[0002]

2. Description of the Related Art Aluminum is used as a base material of a photosensitive drum.
A cylindrical body made of metal such as nickel, brass, and stainless steel is used. Among them, stainless steel is tougher and lasts longer than other metals, that is, it has strength, it is easy to increase the dimensional accuracy by machining, and it is difficult to generate vibration noise even if contact electrification is used. It is preferable because it has the advantage of being able to withstand However, when a photosensitive drum using a stainless steel substrate is subjected to contact charging by using a charging member such as a roller, a blade, or a brush to which a voltage is applied, there is a problem that the photosensitive layer is easily damaged by abnormal discharge during charging. It was This phenomenon is considered to be due to the following reasons. That is, in the case of the contact charger, since the current capacity is larger than that of the corona charger, if there is a portion of the photosensitive layer having inferior withstand voltage, the current concentrates there and the current flows until it is destroyed by discharge. The phenomenon occurs. In the case of charging by a corona charger, since the current capacity is small, the current does not flow in a concentrated manner as described above and the photosensitive layer is not destroyed unless otherwise noted. When the photosensitive layer is destroyed, not only the electric charge is not applied to that portion but an image defect is caused, and the charging member may be destroyed by an abnormal current. As a result, it is expected that the charging will be uniform. become unable.

When stainless steel is used, discharge breakdown easily occurs because the hardness is higher than that of aluminum and the like.
It is presumed that the abnormal protrusions on the surface of the substrate are difficult to smooth. In order to prevent this, it is necessary to grind the surface of the substrate so that the surface roughness Rmax is 2.0 μm or less. To perform grinding, a centerless polishing device as shown in FIG. 4 or a device as shown in FIG. 5 for pressing and grinding a grinding film is used. By the way, when a stainless steel substrate is ground by such an apparatus, grinding powder is generated and a large amount adheres not only to the surface of the substrate but also to the inner surface. When the coating liquid is applied to the surface of the substrate to form the photosensitive layer, the grinding powder adhered to the inner surface may be mixed in the coating liquid and adhere to the coating film on the surface. If grinding powder adheres to the coating film, it is very inconvenient because discharge breakdown always occurs in the case of contact charging.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a photosensitive drum in which not only the surface of the base body but also the inner surface thereof is cleaned at the same time when a stainless steel cylindrical body is used as the base body, so that discharge breakdown is less likely to occur. With the goal. That is, it is an object of the present invention to provide a method of cleaning a photosensitive drum substrate for producing a photosensitive drum that is less likely to cause discharge breakdown.

[0005]

The present invention is characterized in that the surface of a stainless steel cylinder is ground so that Rmax is 2.0 μm or less, and then the surface and the inner surface are simultaneously cleaned with a brush.

The present invention will be described in more detail. In the present invention, the photosensitive drum substrate is manufactured by first grinding the surface of a stainless steel cylinder (stainless steel pipe) so that the surface roughness Rmax is 2.0 μm or less. However, Ra is preferably 0.1 μm or more in order to prevent generation of an interference fringe pattern that occurs when the laser beam is irradiated. The surface of the stainless steel pipe can be ground with a rotary grindstone, a sandper, a polishing belt, or the like.

FIG. 4 is a schematic configuration diagram of a centerless grinding apparatus for grinding the surface of a stainless steel pipe.
The centerless grinding device is composed of three sets of grindstones consisting of a pair of opposed rotary grindstones, namely grindstones 5 and 5, grindstones 6 and 6, grindstones 7 and 7, and grindstones 5 and 6,
It consists of fine abrasive grains in the order of 7. The pair of rotating grindstones facing each other are installed so that the rotating speeds thereof are different from each other, whereby the stainless steel pipe 4 placed thereon is rotated. In addition, each rotating grindstone facing
The distance can be adjusted so that the stainless steel pipe moves sequentially with the grindstones 5 and 5, the grindstones 6 and 6, and then the grindstones 7 and 7. In this grinding machine, stainless steel pipe 4
Is placed on two rotating grindstones 5 and 5, is ground while rotating, and is sequentially ground by the grindstones 6 and 6 and grindstones 7 and 7.

FIG. 5 is a schematic diagram of another surface grinding apparatus for grinding the surface of a stainless steel pipe. In this case, the grinding film 9 coated with polishing powder is used,
It is sent out from the supply roll 10 and is pressed against the surface of the rotating stainless steel pipe 4 by a pressing roll 8 with an appropriate pressure. The grinding film is taken up by the take-up roll 11.

FIG. 2 shows the result of measuring the roughness of the surface of a stainless steel pipe.
A high protrusion exceeding the height is recognized. The surface roughness R
max is 3.5 μm. If such a stainless steel pipe is used as it is, the problems as described in the above-mentioned conventional technique occur. On the other hand, in the present invention, the surface roughness Rmax is 2.0 μm or less by grinding the stainless steel pipe.
FIG. 3 shows an example thereof, and shows the result of measuring the surface roughness of a ground stainless steel pipe. As is clear from FIG. 3, no protrusion exceeding 2 μm is recognized, and the surface roughness Rmax is 2.0 μm or less. Note that Rmax is preferably 0.1 μm or more in order to prevent the occurrence of interference fringe patterns that occur when the laser light is irradiated.

Next, the stainless steel pipe whose surface is ground as described above is washed. 1A and 1B are schematic configuration diagrams of an apparatus for cleaning a photosensitive drum substrate using a brush, in which FIG. 1A is a vertical sectional view and FIG. 1B is a horizontal sectional view.
In the figure, the surface cleaning brush 21 mounted on the brush support 22 while rotating the photosensitive drum substrate 1
The inner surface cleaning brush 23 attached to the brush support 24 is rotated to clean the surface and the inner surface at the same time. At the time of cleaning, the cleaning liquid 25 is sprayed on the surface of the photosensitive drum substrate. A cleaning liquid may be sprayed on the inner surface cleaning brush 23 before cleaning the substrate, or the brush support 24 may be used.
You may make it inject from the inside. Brush material is nylon, polyester, rayon, cellulose,
Polypropylene or the like is used, and the thickness is 50 to 100 μ.
About m is preferable. The cleaning liquid is sent to the nozzle 26 from the outside through the pipe 27. As a result, in addition to oil, grinding powder can be removed. Simultaneous cleaning of the front and back sides is effective in preventing the other surface from being contaminated at the same time as grinding and greatly improving the work efficiency such as simultaneous supply of the cleaning liquid. To clean the photosensitive drum base, there is also a method of immersing the photosensitive drum base in a cleaning liquid and applying ultrasonic waves. This is effective for cleaning oil, but the polishing powder adhering to the inner surface is cleaned. It is difficult, so it is not preferable.

The rotation speed of the photosensitive drum substrate is 10 to 100.
rpm, rotation speed of surface cleaning brush is 10 to 100r
pm is preferred. The inner surface cleaning brush may not be rotated, or may be rotated in the opposite direction to the substrate at 10 to 100 rpm. The cleaning liquid is sprayed from the nozzle 26 onto the photosensitive drum substrate and / or the brush. Cleaning time is 30 ~
It is estimated from the cleaning degree in about 120 seconds.

As the cleaning liquid, there are freon-based solvents and organic solvent-based ones such as chlorinated hydrocarbons. From the viewpoint of environmental protection, an aqueous cleaning liquid is preferably used. A typical aqueous cleaning solution is a solution obtained by adding a surfactant to water. The surfactant which is preferably used in combination with water is a compound composed of a hydrophobic group and a hydrophilic group, has a property of easily gathering at the interface between two substances (substrate-oil), and is effective in separating the two substances. . The hydrophilic groups are roughly classified into two types, ionic type and nonionic type. The ionic type includes alkylbenzene, higher alcohol, sulfate such as α-olefin, sulfonate, silicate, carbonate or phosphate, alkyltrimethylammonium chloride or alkyldimethylbetaine, and the nonionic type. There are higher aliphatic alcohol ethylene oxide adducts (polyethylene glycol alkyl ether) and the like, and any of them effectively works in the present invention.

The detergent concentration of the cleaning liquid is 0.1-10.
% Is preferable. In addition, in order to further reduce the surface tension of water and enhance the effect of the surfactant, it is also effective to use a small amount of a fluorine-based surfactant together. Such a fluorine-based surfactant is a surfactant having a completely fluorinated fluorocarbon chain as a hydrophobic group, not a hydrocarbon chain, but compared with a normal hydrocarbon-based surfactant, Has much higher surface activity. Specifically, there are fluoroalkylcarboxylic acid, perfluoroalkylcarboxylic acid, perfluoroalkylalkoxylate, perfluoroalkylpolyoxyethylene ethanol, fluoroalkyl ester, disodium N-perfluorooctanesulfonylglutamate and the like. Of these, perfluoroalkyl alkoxylates, perfluoroalkyl polyoxyethylene ethanol, fluoroalkyl esters and the like are preferably used in the present invention. The addition amount is 10 to 100 with respect to water.
About ppm is sufficient. The photosensitive drum substrate brush-cleaned with the water-based cleaning liquid is rinsed with pure water, immersed in warm pure water as needed, and then dried. In order to completely perform rinsing, it is also effective to overflow pure water or apply ultrasonic waves.

[0014]

【Example】

Example 1 and Comparative Example 1 30 mmφ × 253 mmL × 0.4 mmt SUS30
4 pipes were prepared, and the surfaces of the pipes were ground by the centerless grinding device shown in FIG. What was taken out at the stage of rough cutting had a surface roughness Rmax = 3.5 as shown in FIG.
μm and Ra = 0.40 μm (Comparative Example 1). What was ground with a finer grindstone had the surface roughness shown in FIG. 3, and Rmax = 1.8 μm and Ra = 0.22 μm (Example 1). These pipes were attached to the brush cleaning machine shown in FIG. 1, and the substrate was rotated at 60 rpm, the surface cleaning brush was rotated at 60 rpm, and the inner surface cleaning brush was rotated at 30 rpm. At that time, an aqueous cleaning solution containing 0.2% of an ionic sulfonate type surfactant (Erwan, manufactured by Lion Corporation) was sprayed with a nozzle. After washing for 2 minutes, the pipe was immersed in pure water for rinsing, then immersed in warm pure water at 60 ° C., and then pulled up at a speed of 200 mm / min to be dried. Rinsing was performed for 30 seconds while applying ultrasonic waves.

These pipes were used as a photosensitive drum base, and a methanol / butanol mixed solution of a type 8 nylon resin (Toresin F30, manufactured by Teikoku Kagaku) was dip-coated on the surface of the photosensitive drum base to form an undercoat layer having a thickness of 1 μm. On top of that, X
A solution of a metal-free phthalocyanine polyvinyl butyral resin (ESREC BM1, manufactured by Sekisui Chemical Co., Ltd.) was dipped and coated with a solution dispersed at a weight ratio of 3: 1 to form a charge generation layer having a thickness of 0.25 μm. Further, a coating solution comprising a mixture containing N, N'-diphenyl-N, N'-bis (m-tolyl) benzidine and a polycarbonate Z resin in a ratio of 36:64 was applied by dip coating to obtain a film thickness. A charge transport layer having a thickness of 18 μm was formed to obtain a photosensitive drum. A charging roll was attached to this photosensitive drum to produce a photosensitive drum unit.
The charging roll used was as follows. That is, 5 mmφ
On the outer circumference of the stainless steel shaft, 0.5% of lithium perchlorate was added to form an elastic layer made of polyether polyurethane rubber with conductivity of 0.001% on the surface. The coating liquid consisting of the polyester-based polyurethane emulsion resin aqueous solution to which the methylphenyl silicone leveling agent of 1. was applied by the dip coating method and dried at 120 ° C. for 20 minutes to give a film thickness of 2
What formed the 0-micrometer coating layer was used.

An image writing device using a semiconductor laser, a one-component toner developing device,
The image was evaluated by mounting it on a printer equipped with a transfer device and a cleaning device equipped with a urethane rubber blade. A direct current component of -600 V and an alternating current component of 400 Hz and a superimposed voltage of 1800 V were applied to the charging roll to charge the photosensitive drum. As a result, the surface potential is −
It became 600V. Then, reverse image exposure was performed and the print image was evaluated. As a result, when the photosensitive drum substrate of Example 1 was used, an image with good image quality free of interference fringe patterns and image defects such as black and white dots was obtained. On the contrary,
When the photosensitive drum substrate of Comparative Example 1 was used, an abnormal current flowed at the time of contact charging, and black spots frequently occurred when the image was viewed.
This is because the photosensitive layer was destroyed by the abnormal discharge and no electric potential was applied to that portion, and it appeared as a black dot because it was an inverted image. When the surface of the photosensitive drum corresponding to the black spots was examined, it was found that the metal was exposed,
It was confirmed that abnormal protrusions on the surface of the photosensitive drum substrate were the cause.

Example 2 In the above Example 1, when the grinding was further finely finished and the surface roughness was set to Rmax = 0.5 μm and Ra = 0.08 μm, a photosensitive drum unit was prepared in the same manner as described above, and similarly. When the image was evaluated, black spots were not recognized, but an interference fringe pattern was generated in the halftone image. However, when used in a printer that does not output a halftone image, no problems occurred.

Comparative Example 2 A photosensitive drum was produced in the same manner as in Example 1, except that the inner surface cleaning brush was removed when the photosensitive drum substrate was cleaned. When this photosensitive drum was attached to a printer and image evaluation was performed, black spots were sometimes generated in a portion corresponding to the lower portion of the photosensitive drum substrate. When the photosensitive drum in that portion was analyzed, metal powder was found to have adhered. It is considered that this was mixed from the inner surface of the substrate when the photosensitive layer or the like was dip-coated on the surface, and it was necessary to wash the inner surface as well.

Example 3 In addition to the water-based cleaning liquid, a fluorine-based surfactant (Megafuck F
-833, manufactured by Dainippon Ink and Chemicals, Inc.) was added in an amount corresponding to 20 ppm of water. The cleaning ability was improved, and the cleaning time of the photosensitive drum substrate was 30 seconds.

[0020]

EFFECTS OF THE INVENTION Abnormal protrusions are scraped off by grinding the surface of a stainless steel cylinder, and Rmax is 2.0.
Since the photosensitive drum is manufactured after cleaning the inner surface of the cylindrical body made of stainless steel with a brush, even if the photosensitive drum is contact-charged, electrostatic damage of the photosensitive layer is prevented. It never happens.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a brush cleaning machine for cleaning a stainless steel cylinder.

FIG. 2 is a diagram showing the surface roughness of a stainless steel cylindrical body of Comparative Example 1.

FIG. 3 is a diagram showing the surface roughness of the stainless steel cylindrical body of Example 1.

FIG. 4 is a schematic configuration diagram of a centerless grinding device.

FIG. 5 is a schematic configuration diagram of an example of another surface grinding apparatus.

[Explanation of symbols]

1 ... Photosensitive drum substrate, 4 ... Stainless steel pipe, 5,
6, 7 ... Rotating whetstone, 8 ... Pressing roll, 9 ... Grinding film, 10 ... Supply roll, 11 ... Winding roll, 21
... Brushes for cleaning the surface, 23 ... Brushes for cleaning the inner surface, 22 and 24 ... Brush support, 25 ... Cleaning liquid, 26 ... Nozzle, 27 ... Piping.

Claims (2)

[Claims] 1. A method for cleaning a photosensitive drum substrate, which comprises grinding the surface of a stainless steel cylindrical body to a surface roughness Rmax of 2.0 μm or less, and then simultaneously cleaning the surface and the inner surface with a brush. . 2. The method for cleaning a photosensitive drum substrate according to claim 1, wherein an aqueous cleaning solution containing a surfactant is used when cleaning with a brush.