JPH0341455A - Surface roughening treatment method for electrophotographic photoreceptor - 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 specifying the nip width between a film-like polishing material and the electrophotographic sensitive body to a prescribed value or above. CONSTITUTION:The film-like polishing material 11 is pressed by a rubber roller 13 to the electrophotographic sensitive body 10 under rotation and the nip width 21 of the contact part between the polishing material 11 and the photosensitive body 10 is specified to >=3.6 mm. 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 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, therefore, the insufficiently roughened surface state is resulted and the inversion of the blade arises if the nip width is below 3.6 mm. The polishing material 11 formed by applying and fixing polishing particles of Al2O3, SiC, Cr2O3, diamond, etc., onto a base material of a high-polymer film consisting of polyethylene, etc., is used as the film-like polishing material 11.

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 method 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 residual toner. In this method, the roller of the fur brush is rotated so as to be in contact with the surface of the photoconductor to remove or knock off the remaining toner.

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 plate 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 A, that is, in the counter direction 53 and the opposite direction.

This phenomenon of reversal of the cleaning blade is more likely to occur when the surface of the photoreceptor is made hard, that is, difficult to scrape, in order to extend the life of the photoreceptor. In addition, when the toner particle size is made uniform and minute toner particles are removed to improve image quality, the lubricity caused by I-toner entering the gap between the cleaning blade and the photoreceptor surface weakens, making it more Blade reversal becomes more likely to occur.

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 inversion and edge chipping are likely to occur.

Therefore, the present applicant previously proposed in Japanese Patent Application No. 62-256769 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. 1-92133 and JP-A-57-94772; As described in Japanese Unexamined Patent Publication No. 52-26226, the surface layer is made into an elastic shape by applying drying conditions, or exposed to a solvent. 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 photoreceptor, 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 photoreceptor. 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 roughening 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 material, in which the nip width between the film-like abrasive material and the electrophotographic photoreceptor is set to 3.6 mm or more. This is a surface roughening treatment method for an electrophotographic photoreceptor.

The present invention will be specifically explained below.

FIGS. 1(a) and 1(b) show 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 counterclockwise, and this abrasive material 11 moves in a direction 12 that intersects with the direction of the rotation axis of the photoreceptor 10. . On the other hand, the film-like abrasive material 11 is transferred to the feed roller 14.
The paper is sent out from the machine and wound up by a winding roller 15. At this time, the rubber roller 13, which is an elastic member, presses the abrasive material 12 against the photoreceptor 10.

FIG. 2 is an enlarged view of the portion where the film-like abrasive material is in pressure contact with the electrophotographic photoreceptor, viewed from directly above. The film-like abrasive material 11 is pressed against the electrophotographic photoreceptor 10 by a rubber roller 3, and the nip width 21 at the contact portion between the abrasive material 11 and the photoreceptor 10 is 3.6 mm or more. .

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.

If the nip width is less than 3 or 6 mm, there will be areas that do not come into contact with the abrasive material due to eccentricity of the photoreceptor, resulting in a partially unroughened or insufficiently roughened surface, which may cause blade reversal. That's what happens. Therefore, set the nip width to 3 or 6.
By setting the diameter to be equal to or greater than mm, the abrasive material is uniformly pressed against the photoreceptor, thereby making it possible to uniformly roughen the surface of the photoreceptor.

The elastic member 13 used in the present invention may be a non-rotating pressing member in addition to the roller used in the above specific example.

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 defined by the 10-point average surface 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 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 a drum-shaped metal such as aluminum, 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 plastyrill or paper. Alternatively, one molded into a sheet can be used.

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.

Further, an intermediate layer such as a subbing layer may be provided between the conductive support 31 and the photosensitive layer 32 to improve adhesiveness and barrier properties. 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 an appropriate hardness, so that it can be prevented from becoming rough on the surface of the photoreceptor. It works effectively.

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] O is developed by a developing device 44.

The toner image formed by the development is transferred by a transfer charger 45 onto a transfer material moving in an arrow direction 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, 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 of 80 φ x 360 mm was used as a support, and a 5% methanol solution of nylon (6-66-61, O-12 quaternary nylon copolymer) was applied by dip coating to form a 1 μm thick undercoat layer. Ta.

Next, add 10 parts (parts by weight, the same applies hereinafter) of a disazo pigment having the following structural formula to polyvinyl butyral (degree of butyralization: 68%, number average molecular weight: 20%).
000) and 50 parts of cyclohexanone were dispersed for 20 hours in a sand mill using Iφ glass beads. 70 to 120 (appropriate) parts of methyl ethyl ketone were added to this dispersion and coated on the undercoat layer to form a charge generation layer with a thickness of 0.1 μm.

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 applied by dip coating onto the charge generation layer to form a charge transport layer having a thickness of 18 μm. The average surface roughness of this photoreceptor was 0.0 μm.

Next, a film-like abrasive material (manufactured by Sumitomo 3M Co., Ltd., manufactured by Sumitomo 3M,
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 FIG. A rubber roller (diameter 60
As shown in FIGS. 1 and 2, a film-like abrasive material was brought into pressure contact with the photoreceptor using a nip width of 4.0 mm. In this device, the film-like abrasive material is
It is designed to move at a speed of mm. Using this device, the fabricated photoreceptor was rotated at a distance of 320 mm.
When the surface was roughened with a width of Ta. Using this photoreceptor, charging, image exposure, development, transfer, and a cleaning blade (linear pressure tx,
The sample was incorporated into an electrophotographic apparatus (NP-3525, manufactured by Canon) having the same configuration as shown in FIG.

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.

Using the apparatus of Example 1, the nip width between the abrasive material and the photoconductor was set to 2 and 0.
When the surface was roughened to m m, the average surface roughness (Rz)
The average surface roughness was 0.6 μm and the maximum surface roughness was 1.2 μm, but the average surface roughness was 0.6 μm in a part of the center of the photoreceptor. I 1. tm, a rough part with a maximum surface roughness of 0.4 μm was formed.

This seems to be because the probability of contact decreases when the contact area is narrow due to insufficient roundness of the photoreceptor. When the photoreceptor treated in this way was placed in the electrophotographic apparatus used in Example 1 and image output was evaluated,
The polyurethane rubber blade turned over from the center of the photoreceptor where the surface roughness was small, making it impossible to rotate the photoreceptor.

Example 14 2L Instead of the abrasive material with a film grain size of 6 μm used in the apparatus of Example 1, an abrasive material with a film grain size of 9 μm was used to perform surface roughening treatment at the nip width shown in Table 1. Table 1 also shows the average surface roughness (Rz) of the obtained surface, the maximum surface roughness, and the results of durability evaluation of 100,000 sheets after being installed in an electrophotographic apparatus.

Table 1 Note 1E Example "Hea 1" In place of the nip width between the abrasive and the photoreceptor used in Examples 2 and 3, the surface roughening treatment was performed in the abutment shown in Table 2.

As shown in the table above, by roughening the surface by setting the nip width between the abrasive material and the electrophotographic photoreceptor to 3.6 mm or more, it is possible to stably obtain a uniform surface over the entire surface, making it easier to clean the cleaning blade. No reversal occurs.

〔Effect of the invention〕

As explained above, by roughening the surface by setting the nip width between the film-like abrasive material and the electrophotographic photoreceptor to 3 to 6 mm or more, it is possible to stably obtain a uniform surface over the entire surface of the photoreceptor. Even when used in an electrophotographic device, there is no reversal of the cleaning blade, and high-quality images can always be obtained.

[Brief explanation of drawings]

FIG. 1(a) is a schematic perspective view of an example of an apparatus for carrying out the surface roughening treatment method of the present invention, and FIG.
Fig. 2 is a schematic diagram of the apparatus in a) viewed from above; Fig. 2 is a schematic diagram of the state in which the film abrasive material and the electrophotographic photoreceptor are in contact; Fig. 3 is a schematic cross-sectional view of the electrophotographic photoreceptor; 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.

Claims (1)

[Claims] (1) In a method of roughening the surface of an electrophotographic photoreceptor by rubbing a film-like abrasive material, the nip width between the film-like abrasive material and the electrophotographic photoreceptor is set to 3.
A method for roughening the surface of an electrophotographic photoreceptor, the method comprising roughening the surface of an electrophotographic photoreceptor.