JPH0341456A - Surface roughening treatment of electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain a uniformly roughened surface state with which the inversion of a cleaning blade is obviated and always good-quality images are obtainable by bringing a film-like polishing material into pressurized contact with the electrophotographic sensitive body by means of an elastic member having a prescribed hardness. CONSTITUTION:The film-like polishing material 11 is brought into pressurized contact with the photosensitive body 10 under rotation by means of a rubber roller 13 which is the elastic member. The surface of the photosensitive body is roughened uniformly over the entire part thereof when the polishing material 11 moving in this direction 12 is moved in parallel with the rotating direction of the photosensitive body 10. The hardness of the elastic member is 30 to 85 deg., more preferably 45 to 75 deg.. The part where the photosensitive body does not come into contact with the polishing material 11 is formed by the eccentricity of the photosensitive body 10, etc., and the insufficiently roughened surface state is resulted if the hardness is <30 deg.. The photosensitive body 10 is deeply flawed and image defects are generated if the hardness is >=85 deg..

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a surface roughening treatment method for an electrophotographic photoreceptor,
Specifically, the present invention relates to a surface roughening treatment method for an electrophotographic photoreceptor having good leaning properties and image characteristics.

[Conventional technology]

Generally, in an electrophotographic process, an electrophotographic photoreceptor is repeatedly subjected to a cycle consisting of at least charging, exposure, development, transfer, and cleaning steps.

In particular, the cleaning process for removing residual toner on the photoreceptor after the transfer process is an important process for always obtaining clear copy images.

There are usually the following two methods for this cleaning.

One is to press a rubber plate-shaped member called a blade onto the photoconductor to eliminate the gap between the photoconductor and the blade, thereby preventing toner from slipping through and scraping off any remaining toner. Rotate the roller of the fur brush so that it comes into contact with the surface of the photoreceptor to remove the remaining toner. Or there is a method of knocking it down.

Among these, rubber blades are cheaper and easier to design, so cleaning using blades is currently the mainstream. Especially when performing natural color development,
Natural colors are produced by layering the three primary colors of magenta, cyan, and yellow, or four colors including black, so the amount of toner used is far greater than normal one-color development, so the rubber blade is exposed to light. It is best to use a pressure cleaning method.

In addition, as a method of pressing the cleaning blade against the photoreceptor, there are two methods for pressing the cleaning blade against the photoreceptor 1: a counter direction 51 as shown in FIG. It is known that the cleaning performance is better in the counter one direction.

However, a cleaning blade that exhibits excellent cleaning performance has a drawback in that the cleaning blade tends to reverse because of the large frictional force with the photoreceptor. This reversal of the cleaning blade can be done, for example, in Figure 5 (
Cleaning blade 5 in the counter direction shown in a)
9 is a phenomenon in which the photoreceptor 10 is warped in the moving direction A1, that is, in the counter direction 53 and the opposite direction.

This phenomenon of cleaning blade reversal is more likely to occur if the surface of the photoconductor is made hard and difficult to scrape in order to extend the lifespan of the photoconductor.Also, to improve image quality, the toner particle size is made uniform. When minute amounts of toner are removed, the lubricity caused by the toner entering the gap between the cleaning blade and the surface of the photoreceptor weakens, making it even more likely that the blade will reverse.

In addition, when performing natural color development, developing one image requires three or four times using toners of magenta, cyan, and yellow, or four colors including black. As a result, the load applied to the cleaning blade increases, making it more likely that the blade will flip over or even chip its edge.

Additionally, when the surface layer of the photoreceptor is made of organic material, the frictional resistance between the blade and the photoreceptor surface increases compared to an inorganic surface.
In particular, blade flipping and edge chipping are likely to occur.

Therefore, the present applicant previously proposed in Japanese Patent Application No. 62-257669 that the surface of the photoreceptor be roughened in advance. According to this, the contact area between the photoconductor surface and the cleaning blade is reduced, and the cleaning blade is easily provided with lubricity caused by minute toner entering the gap between the photoconductor surface and the blade. This can prevent cleaning defects such as reversal.

On the other hand, as a method for roughening the surface of a photoreceptor, there is
A mechanical polishing method such as a sandblasting method using a brush or an abrasive as described in JP-A No. 3-92133 and JP-A-57-94772; As described in JP-A No. 52-26226, the surface layer can be coated with powder in advance, as described in Japanese Patent Laid-Open No. 52-26226. There are methods such as adding particles and coating to make the surface rough. Among these methods, the mechanical polishing method is the most preferable in that it increases the lubricity between the cleaning blade and the surface of the photoreceptor. This is because the shavings generated on the surface of the photoreceptor during mechanical polishing act as a lubricant.

[Problem that the invention seeks to solve]

However, in the conventional mechanical polishing method, which roughens the surface by pressing an abrasive onto the photoconductor, it is difficult to control the conditions for applying the abrasive, and it is difficult to stably obtain a uniform rough surface over the entire surface of the photoconductor. That was difficult. In particular, when the photoreceptor is eccentric, unroughened areas tend to appear in that area.

An object of the present invention is to provide a surface roughening treatment method for an electrophotographic photoreceptor that can obtain a uniform roughened state over the entire surface of the photoreceptor.

Another object of the present invention is to provide a surface roughening treatment method for an electrophotographic photoreceptor that can form a roughened surface that prevents cleaning failures due to inversion of the cleaning blade, chipping of edges, etc. There is a particular thing.

[Means for Solving the Problems] As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that it is possible to manufacture an electrophotographic photoreceptor that is superior in a specific surface roughening treatment. I found out what I can do.

That is, the present invention provides a method for roughening the surface of an electrophotographic photoreceptor by rubbing a film-like abrasive, in which the electrophotographic photoreceptor is subjected to film-like polishing with an elastic member having a hardness of 30° or more and 85° or less. This is a surface roughening treatment method for an electrophotographic photoreceptor, which is characterized in that materials are brought into pressure contact.

The present invention will be specifically explained below.

FIGS. 1 and 2 are schematic diagrams of a specific example of an apparatus for carrying out the surface roughening treatment method of the present invention. A film-like abrasive material 11 rubs against the electrophotographic photoreceptor 10 that rotates clockwise or in the opposite direction.
It is moving in a direction 12 intersecting the direction of the rotation axis. On the other hand, the film-like abrasive material 11 is sent out from the delivery roller 14 and taken up by the take-up roller 15. At this time, the rubber roller 13, which is an elastic member,
1 is pressed against the photoreceptor 10.

If the abrasive material moving in this direction 12 is moved in a direction parallel to the rotational axis direction of the photoreceptor 10, the entire surface of the photoreceptor can be uniformly roughened.

Note that this device may be used standing up or lying down.

The hardness of the elastic member in the present invention is 30° or more and 85° or less, more preferably 45° or more and 75° or less. The hardness of the elastic member was measured using a JIS-A type hardness meter (Chiklok G5706, manufactured by Chiklok Co., Ltd.) using a measuring method based on JIS K6301.

If the hardness is less than 30°, there will be a portion that does not come into contact with the abrasive material due to eccentricity of the photoreceptor, resulting in a partially unroughened or insufficiently roughened surface, resulting in blade reversal. Furthermore, if the hardness exceeds 85°, deep scratches will occur on the photoreceptor, resulting in image defects. Therefore, by setting the hardness to 30° or more and 85° or less, the abrasive material is evenly pressed against the photoreceptor, so that the surface of the photoreceptor can be uniformly roughened.

In addition to the roller used in the above specific example, the elastic member in the present invention may be a non-rotating pressing member. Examples of the material of the elastic member include urethane-based, silicone-based, diene-based rubber, and rubber-like substances.

Film-like abrasive materials used in the practice of the present invention include those in which abrasive particles of aluminum oxide, silicon carbide, chromium oxide, diamond, etc. are coated and fixed on a polymeric film base material such as polyester.

The roughened state of the photoreceptor surface formed by the surface roughening treatment method of the present invention is the IO point uneven roughness Rz (hereinafter simply referred to as average surface roughness) defined by JIS standard BO601.
is preferably 0.3 μm or more and 5.0 μm or less,
More preferably, it is 0.3 μm or more and 2.0 μm or less.

When the average surface roughness is larger than 5.0 μm, streak-like image defects tend to appear in the image.

Furthermore, when the average surface roughness is less than 0.3 μm, the friction between the cleaning blade and the surface of the photoreceptor is hardly alleviated, and since the surface of the photoreceptor is flat, the effect of roughening it is difficult to be recognized.

The electrophotographic photoreceptor 10 of the present invention has a photosensitive layer 32 laminated on a conductive support 31 as shown in FIG.
This is a laminated photosensitive layer with four functionally separated layers.

The conductive support 31 is made of a metal such as aluminum, an aluminum alloy, or stainless steel, a metal coated with a conductive substance alone or together with a suitable binder resin to provide a conductive layer, or a conductive treated plastic or paper in the form of a drum or the like. It is possible to use one molded into a sheet shape.

The charge generation layer 33 includes a charge generation substance such as an azo pigment, a quinone pigment, a quinocyanine pigment, a perylene pigment, an indigo pigment, or a phthalocyanine pigment, and a binder such as polyvinyl butyral, polystyrene, acrylic resin, polyester, polyvinyl acetate, or polycarbonate. It can be formed by being dispersed in a resin, or it can also be formed as a vapor deposited film using a vacuum evaporation device. The preferred film thickness is
It is 0.01 μm to 3 μm.

The charge transport layer 34 is made of a charge transport material such as a styryl compound, a hydrazone compound, a triarylamine compound, a carbazole compound, an oxazole compound, or a pyrazoline compound, or a polyarylate, polystyrene, acrylic resin, polyester, polycarbonate, etc. It can be formed by being included in a binder resin. The preferred film thickness is 10 μm to 30 μm.

Further, as a structure of the photosensitive layer 32, the charge generation layer 33 may be formed on the charge transport layer 34, and further, the charge generation layer 33 may be formed on the charge transport layer 34.
may be a single layer type in which the charge generating substance and the charge transporting substance described above are contained in the same layer.

Furthermore, an intermediate layer such as a subbing layer for adhesion and barrier properties may be provided between the conductive support 31 and the photosensitive layer 32. Further, a protective layer may be provided on the photosensitive layer 32.

The electrophotographic photoreceptor of the present invention has at least a resin layer on its surface, and the resin shavings scraped by the abrasive particles are fine and have appropriate hardness, which is effective against roughening the photoreceptor surface. It acts on

A specific example of an image forming process using the electrophotographic photoreceptor of the present invention is shown in FIG.

A pre-exposure lamp 41, a primary charger 42, an exposure means 43, a developer 44, a transfer charger 45, a cleaner 47 having a cleaning blade 46, and a fixing device 48 are arranged around the photoreceptor 10 as a basic structure. ing.

In this process, first, the photoreceptor 10 rotates in the direction of the arrow.
On the other hand, the residual potential remaining on the photoreceptor 10 is removed by applying light from the pre-exposure lamp 41. A primary charger 42 charges the photoreceptor 10 from which electricity has been removed.

Next, exposure is performed by the exposure means 43 to project image information corresponding to the original image to form an electrostatic latent image on the photoreceptor 10. The electrostatic latent image on the photoreceptor 10 is developed by a developing device 44 .

The toner image formed by the development is transferred by a transfer charger 45 onto a transfer target moving in the direction of an arrow 49.

The remaining toner on the photoreceptor 10 that has not been transferred to the transfer material is scraped off and cleaned by a cleaner 47 having a cleaning blade 46. On the other hand, the transfer material onto which the toner image has been transferred is conveyed to a fixing device 48, where the toner is fixed.

In this process, the exposure means 43 can be a halogen lamp, a fluorescent lamp, a laser beam, or the like. Other auxiliary processes such as pre-transfer charging may also be used.

Furthermore, the development may be either normal development or reversal development.

An aluminum cylinder with a diameter of 80 φ x 360 mm was used as a support, and nylon (6-66-610-12
A 1 μm thick undercoat layer was provided by dip coating a 5% methanol solution of a quaternary nylon copolymer.

Next, add 10 parts (parts by weight, the same applies hereinafter) of the disazo pigment having the following structural formula to polyvinyl butyral (degree of butyralization: 68%, number average molecular weight: 112%).
0000) 5 parts and 50 parts of cyclohexanone in 1φ
Dispersion was carried out for 20 hours using a sand mill using glass beads.

Add 70 to 120 methyl ethyl ketone (as appropriate) to this dispersion.
A charge generating layer having a thickness of 0.1 μm was formed by coating the undercoat layer on the undercoat layer.

Next, 10 parts of bisphenol Z type polycarbonate (viscosity average molecular weight 30,000) and 10 parts of a hydrazone compound having the following structural formula were dissolved in 65 parts of monochlorobenzene,
This solution was dip-coated on the charge generation layer to form a charge transport layer with a thickness of 18 μm, thereby producing an electrophotographic photoreceptor. The average surface roughness of this photoreceptor was 0.0 μm.

Next, a film-like abrasive film (manufactured by Sumitomo 3M Co., Ltd., manufactured by Sumitomo 3M Co., Ltd.,
A wrapping film) was set on the delivery roller 14 and take-up roller 15 of a surface roughening treatment device similar to that shown in FIGS. 1 and 2. A urethane rubber roller (diameter 40 mm) with a hardness of 60° was used as the elastic member in Figures 1 and 2.
As shown in the figure, a film-like abrasive material was pressed against a photoreceptor. In this device, the film-like abrasive material is moved at a speed of 25 mm per minute.

Using this device, while rotating the fabricated photoreceptor,
When the surface was roughened with a width of 0 mm, the average surface roughness (Rz) was 1.0 μm over the entire surface of the photoreceptor.
The minimum surface roughness was 0.6 μm and the maximum surface roughness was 1.6 μm.

Using this photoreceptor, an electrophotographic apparatus (NP-3525) having the same configuration as shown in FIG. , made by Canon)
The images were repeatedly evaluated by incorporating them into

As a result, there were no cleaning defects caused by the cleaning blade turning over, etc., and when the copied images were carefully visually observed, no image defects due to surface roughness were observed, and good copy images were produced on up to 100,000 copies. Obtained.

Roughness Calibration When the hardness of the rubber roller was changed to 9° in the apparatus of Example 1 and the surface roughening treatment was performed, the average surface roughness of the surface of the photoreceptor was 3.3 μm 1 minimum surface roughness 1. The maximum surface roughness was 7.7 μm. This is 5. Due to the high hardness of the rubber roller, when the surface was roughened, the pressure of the abrasive against the photoreceptor became too high, causing deep scratches on the surface of the photoreceptor. When the photoreceptor treated in this manner was incorporated into the electrophotographic apparatus used in Example 1 and image output was evaluated, deep scratches of 5 μm or more appeared as streaks in the image.

6 2345 and 6 Instead of the abrasive material with a film grain size of 6 μm used in the apparatus of Example 1, a surface roughening treatment was performed using an abrasive material with a film grain size of 9 μm and an elastic member having the hardness shown in Table 1. . Table 1 also shows the average surface roughness (Rz), minimum surface roughness, maximum surface roughness of the obtained surface, and the results of durability evaluation of 100,000 sheets after being installed in an electrophotographic device.

Table 1 Ratios 2 and 3 Instead of the elastic members having the hardnesses used in Example 2, the elastic members having the hardness shown in Table 2 were used to perform the surface roughening treatment.

Table 2 As shown above, the hardness of the elastic member used to press the abrasive material against the electrophotographic photoreceptor is 30' or more and 85°.
By roughening the surface using the following, it was possible to obtain a uniformly rough surface, and it was possible to prevent reversal of the cleaning blade and streak-like image defects.

〔Effect of the invention〕

As explained above, the hardness of the elastic member used to press the film-like abrasive material against the electrophotographic photoreceptor is 30.
By using an angle between Images can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view of an example of an apparatus for implementing the surface roughening treatment method of the present invention, FIG. 2 is a schematic diagram of the apparatus shown in FIG. 1 viewed from above, and FIG. 3 is an electrophotographic photosensitive Schematic cross-sectional diagram of the body,
FIG. 4 is a schematic cross-sectional view for explaining the image forming process in the electrophotographic apparatus, and FIG. 5 is a schematic diagram showing the contact relationship between the cleaning blade and the electrophotographic apparatus. IO /-' Nri

Claims (1)

[Claims] (1) In a method of roughening the surface of an electrophotographic photoreceptor by rubbing a film-like abrasive material, the film-like abrasive material is applied to the electrophotographic photoreceptor using an elastic member with a hardness of 30° or more and 85° or less. A surface roughening treatment method for an electrophotographic photoreceptor characterized by pressure contact.