JPH0381773A - Method for roughing surface of electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To uniformly rough the surface of a photosensitive body, to reduce the disordered part of film thickness which occurs at the coating time of the photosensitive body and to make the film thickness uniform by properly using grinding materials whose grinding grain size is different according to the part of the photosensitive body. CONSTITUTION:The surface of the photosensitive body 1 is roughed by moving the film-like grinding materials 2 and 2' in a direction shown by an arrow 6 from feeding rollers 3 and 3' to take-up rollers 5 and 5' through presser rollers made of rubber 4 and 4' and making it rub on the surface of the photosensitive body 1 at the positions of the rollers 4 and 4'. for example, the cleaning blade abutting part of the photosensitive body is roughed by using the grinding material having the large grain size (9mum, for example), first, and using the grinding material having the small grain size (0.5 mum, for example), next. Simultaneously, the disordered part of the film thickness on the end part thereof is roughed by using the grinding material having the larger grain size (80mum, for example), first and using the grinding material having the small grain size (1 mum, for example), next.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for surface roughening of an electrophotographic photoreceptor, and more specifically, to a method for roughening the surface of an electrophotographic photoreceptor, and more particularly, to a method for roughening the surface of an electrophotographic photoreceptor, and more specifically, to obtain an electrophotographic photoreceptor with good cleaning properties and image characteristics. This invention relates to a method for roughening the surface of a photographic photoreceptor.

[Conventional technology]

Generally, in an electrophotographic process, a cycle consisting of at least the steps of charging, image exposure, development, transfer, and cleaning is repeatedly performed on an electrophotographic photoreceptor. In particular, the cleaning process for removing residual toner on the photoreceptor after the transfer process is an important process in order to always obtain clear copy images.

The following two methods are generally used for this cleaning. The first method is to press a rubber plate-shaped member called a cleaning blade onto the photoconductor to eliminate the gap between the photoconductor and the cleaning blade, thereby preventing toner from slipping through and scraping off the remaining toner. be. FIG. 2 is a schematic cross-sectional view showing a typical example of a cleaning device using such a leaning blade, in which the cleaning device 7 is arranged close to a cylindrical photoreceptor 8 rotating in the direction of arrow A. , one edge of one end of the cleaning blade 9 attached to the cleaning device is applied to the surface of the photoreceptor 8, either in a counter direction to the rotational direction of the photoreceptor as shown in the figure, or in a direction opposite to the direction of rotation of the photoreceptor. The remaining toner is scraped off by applying pressure in the forward direction shown in the figure (it is known that cleaning performance is better in one direction of the counter). The second method is to wipe or knock off the remaining toner by rotating the roller of the fur brush so that it comes into contact with the surface of the photoreceptor. Of these two methods, since the rubber blade is cheaper and easier to design, cleaning using a cleaning blade is currently the mainstream. Especially when performing natural color development, the three primary colors of magenta, cyan, and yellow,
Alternatively, since natural colors are produced by layering four colors including black, the amount of toner used is much greater than in normal one-color development, so a cleaning method that presses a rubber blade against the photoreceptor is used. is optimal.

However, the cleaning blade that exhibits excellent cleaning properties has a drawback in that the cleaning blade tends to flip over because of the large frictional force with the photoreceptor. This reversal of the cleaning blade means that the counter one direction cleaning blade 9a shown in FIG.
As shown in , this is a phenomenon in which the photoreceptor warps in the direction of movement of the photoreceptor, that is, in the opposite direction to the counter direction.

This phenomenon of the cleaning blade turning over becomes more likely to occur when the surface of the photoreceptor is made hard, that is, less likely to be scraped, in order to extend the life of the photoreceptor. In addition, when toner particle size is made uniform and minute toner particles are removed to improve image quality, the lubricity caused by toner entering the gap between the cleaning blade and the photoreceptor surface is reduced. As it becomes thinner, the cleaning blade is more likely to turn over.

In addition, when performing natural color development, development is performed three or four times using toners of 41 colors, including magenta, cyan, and yellow, or black, to produce one image. As a result, the load applied to the cleaning blade increases, making it more likely that the cleaning blade will be reversed or that the edge portion will be damaged.

Additionally, when the surface layer of the photoreceptor is made of organic matter, the frictional resistance between the cleaning blade and the photoreceptor surface increases compared to an inorganic surface, making it particularly likely that the cleaning blade will flip over and the edges will be damaged. .

Therefore, in Japanese Patent Application No. 62-256769, the applicant previously proposed that the surface of the photoreceptor be roughened in advance so as to avoid deterioration in image quality by cleaning the cleaning blade by inverting the cleaning blade, chipping the blade edge, etc. We proposed a method to prevent defects. The roughening state of the photoreceptor surface is expressed by the 10-point average roughness (Rz) measurement method defined by JIS standard BO601, and the maximum value, average value, and minimum value are all preferably 0.3 to 5. It is within the range of 0 μm, more preferably within the range of 0.3 to 2.0 μm. When the maximum value is larger than 5.0 μm, streak-like defects tend to appear in the image. Further, when the minimum value is smaller than 0.3 μm, the friction between the cleaning blade and the photoreceptor surface is hardly alleviated in some areas, and the effect of roughening the photoreceptor surface is not recognized. The above maximum value, average value and minimum value are 0.3 to 5.
If it is within the range of 0 μm, the contact area between the photoreceptor surface and the cleaning blade will be reduced, and if the particle size is small (approximately 5 μm or less) contained in the toner,
The shavings from the surface of the photoconductor (about 1μ
m or less) easily penetrates into the gap between the photoreceptor surface and the cleaning blade to provide lubricity, thereby making it possible to prevent cleaning failures due to inversion of the cleaning blade, etc.

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 material 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 roughen the surface. Among these methods, the mechanical polishing method is the most preferred in that it increases the lubricity between the cleaning blade and the surface of the photoreceptor.

This is because the shavings on the surface of the photoreceptor generated by mechanical polishing act as a lubricant.

Further, among mechanical polishing methods, a method using a film-like abrasive material is more preferable. The reason for this is that in the case of sandblasting, etc., the abrasive material is easily embedded in the organic electrophotographic photoreceptor, causing pinholes and deteriorating the electrophotographic properties, whereas film-like abrasive material This is because in the case of , there is almost no embedding.

[Problem to be solved by the invention]

However, in the conventional mechanical polishing method, in which the surface of a photoreceptor is polished by pressure contact with an abrasive material to make the surface rough, the roughening state may vary even on the same photoreceptor due to differences in the contact state of the abrasive material, the contact pressure, and the polishing speed. This causes unevenness and it is very difficult to control the roughened state. In areas where the roughened surface is shallow, the friction between the cleaning blade and the photoreceptor is not alleviated, causing the cleaning blade to reverse or There were drawbacks such as loss of edges, and image defects as scratch patterns on the image in deep roughened areas.

Furthermore, when an organic photosensitive layer is coated on a substrate, a sag in the film thickness (usually a convexity of about 50 μm) occurs at the edge of the substrate, and this sag occurs when the toner is fused when used in an electrophotographic process. Since this causes image defects, it is customary to provide a step of peeling off the sagging areas with a solvent after coating the photosensitive layer and before drying. However, when this peeling is performed,
In some cases, the undried photosensitive layer, the solvent splashes, and the coating film is deteriorated by the solvent, which causes a decrease in the yield of photoreceptor production.

SUMMARY OF THE INVENTION An object of the present invention is to provide a surface roughening treatment method for an electrophotographic photoreceptor that can prevent cleaning failures and scratch patterns on images due to reversal of the cleaning blade, loss of edges, and the like.

Another object of the present invention is to provide a surface roughening method that can uniformly roughen the surface of an electrophotographic photoreceptor within a predetermined range in order to prevent this cleaning failure. .

A further object of the present invention is to provide a surface roughening treatment method for an electrophotographic photoreceptor that can reduce and make uniform the film thickness sag that occurs when coating the photoreceptor.

[Means to solve the problem]

As a result of intensive studies on roughening the surface of a photoreceptor, the present inventors have developed a method for roughening the surface of an electrophotographic photoreceptor using a film-like abrasive material, which is suitable for different parts of the photoreceptor. By performing the surface treatment of the photoreceptor using two or more types of abrasives with different abrasive particle sizes, the maximum value expressed by the 10-point average roughness (Rz) measurement method defined in JIS standard BO601, A uniform rough surface whose average value and minimum value (in this specification, these are referred to as maximum surface roughness, average surface roughness, and minimum surface roughness, respectively) are all within the range of 0.3 to 5.0 μm. This makes it possible to prevent poor cleaning, and also to eliminate the sagging of the film thickness that occurs when coating the photoreceptor and to make it uniform.

That is, the present invention provides a method for roughening the surface of an electrophotographic photoreceptor using a film-like abrasive, in which two or more types of abrasives having different abrasive particle sizes are selectively used depending on the part of the photoreceptor. This is a surface roughening treatment method for an electrophotographic photoreceptor, which is characterized by performing surface treatment on the photoreceptor.

In a method of roughening the surface of an electrophotographic photoreceptor using a film-like abrasive, the surface of the photoreceptor that comes into contact with the cleaning blade has a roughening effect when the abrasive particle diameter is less than 0.1 μm. If the diameter is larger than 5060 μm, the photoreceptor will be scratched and image defects will occur.
．． Roughened from 1μm to 50.0μm, approximately 50μm
m The sagging part of the photoreceptor (outside the image area) where dust has risen,
It is a feature of the present invention that the surface is roughened using an abrasive material with a larger abrasive particle diameter, since it takes time to scrape off unless an abrasive material with a larger abrasive particle diameter is used. After the surface roughening of each part of the photoreceptor is completed, it is preferable to add this surface roughening step because the roughened surface will be made uniform by roughening each part with an abrasive having a fine abrasive particle size. .

In carrying out the surface roughening method of the present invention, for example, the first
As shown in the figure, a polishing system consisting of a film-like abrasive material 2, a delivery roller 3, an elastic pressure roller 4, and a take-up roller 5, a film-like abrasive material 2', a delivery roller 3', an elastic pressure roller 4', and a winding system are shown. A polishing system consisting of two or more sets of film-like abrasive material is used, including a polishing system consisting of a take-off roller 5'. This film-like abrasive material 2 (2') is transferred to the feed roller 3 (3')
From there, the winding roller 5
(5') in the direction of arrow 6 (6'), and at this time, the film-like abrasive material 2 (2') slides against the surface of the electrophotographic photoreceptor l at the position of the presser roller 4 (4'). do. The film-like abrasives used in the present invention all have different particle diameters, and an abrasive material with an appropriate abrasive particle diameter polishes each part of the electrophotographic photoreceptor 1.

Film-like abrasives used in the practice of the present invention include those in which fine particles of aluminum oxide, silicon carbide, chromium oxide, diamond, etc. are coated and fixed on a film of polyester or the like.

The electrophotographic photoreceptor treated by the surface roughening method of the present invention has an organic photosensitive layer 11 laminated on a conductive support 10, as shown in FIG. Preferably, it is a laminated photosensitive layer in which a charge generation layer 12 and a charge transport layer 13 are functionally separated.

The conductive support 10 may be a drum-shaped or sheet metal such as aluminum, aluminum alloy, or stainless steel, or a metal coated with a conductive substance alone or with an appropriate binder to provide a conductive layer, or a conductive-treated plastic or paper. Any conventionally known type can be used, such as one with a shaped bottom.

The charge generation layer 12 contains 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 binding agent 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 0
．． 01-3 μm.

The charge transport layer 13 contains 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 charge transport material such as a polyarylate, polystyrene, acrylic resin, polyester, or polycarbonate. It can be formed by being dispersed in a binder resin. The preferred film thickness is 10-301, tm. In addition, the photosensitive layer 11
As a structure, the charge generation layer 12 may be formed on the charge transport layer 13, and furthermore, the photosensitive layer 11 may be a single layer type in which the charge generation substance and the charge transport substance described above are contained in the same layer. Good too.

Furthermore, an intermediate layer such as an undercoat layer may be provided between the conductive support 10 and the photosensitive layer 11 in order to improve adhesiveness and barrier properties.

The electrophotographic photoreceptor whose surface has been roughened by the method of the present invention is used in an electrophotographic process having a cleaning means using a rubber blade brought into contact with the photoreceptor in one counter direction.

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

Next, 10 parts (parts by weight, the same shall apply hereinafter) of a diazo pigment with the following structural formula, 5 parts of polyvinyl butyral (degree of butyralization 68%, number average molecular weight 20,000), and 50 parts of cyclohexanone were added to lφ
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 .mu.m was formed by coating the undercoat layer on the undercoat layer.

Next, 10 parts of bisphenol type 2 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, and this solution was dip-coated onto the charge generation layer to form a 18 μm thick layer. A charge transport layer was formed. When forming these layers, sufficient drying was performed. The average surface roughness of this photoreceptor is 0
．． It was 0 μm. Further, the yield of this photoreceptor was 97%.

Now, using the apparatus shown in FIG. 1, the photoreceptor produced by the above method was first coated with an abrasive material having an abrasive particle size of 9.0 μm, and then with an abrasive material having an abrasive particle size of 0 μm. While roughening the surface with a 5 μm abrasive, at the same time, for areas where the film thickness deteriorates, the initial abrasive particle size is 80.0 μm.
The average surface roughness of this photoreceptor was
Rz) is 1.0 μm, the minimum and maximum surface roughness are 0.8 μm and 1.2 μm, respectively, and the film thickness unevenness is 3.
The convexity was 8 μm. In addition, the yield of the surface roughening process is 100%.
Met. Then, this photoreceptor is charged, image exposed, developed, transferred, and cleaned with a rubber blade (linear pressure: 11 g).
/cm) and was incorporated into an electrophotographic device (NP-3525, manufactured by Canon) and repeated image output evaluations were performed, and no problems occurred until 10,000 copies were printed. This is Example 1 and the results are shown in Table 1.

<Example 2> In a photoconductor coated in the same manner as in Example 1, abrasive particles with a diameter of 12
, 0 μm abrasive material, while areas where the film thickness deteriorated were first roughened with a 70.0 μm abrasive particle diameter, and then polished with a 0.3 μm abrasive particle diameter. When both parts were roughened with a material, the average surface roughness (Rz) of this photoreceptor was 1.1 μm, and the minimum and maximum surface roughness were 0.8 μm and 1.4 μm, respectively. The film thickness unevenness was a convexity of 5.0 μm. Moreover, the yield of the surface roughening step was 100%. When this photoreceptor was incorporated into the same electrophotographic apparatus as in Example 1 and image output evaluation was repeated, no problems occurred until 10,000 copies were printed. This is referred to as Example 2 and the results are shown in Table 1.

<Example 3> In a photoconductor coated in the same manner as in Example 1, an abrasive particle with a diameter of 8 was initially applied to the contact area of the cleaning blade.
．． The surface is roughened with an abrasive of 0 μm and then with an abrasive with an abrasive particle size of 0.3 μm, while at the same time, for areas where the film thickness is degraded, only an abrasive with an abrasive particle size of 45.0 μm is used. When the surface was roughened, the surface average surface roughness (Rz) of this photoreceptor was
is 1.2 μm, and the minimum and maximum surface roughness are each 0.
9μms 1.4μm, and the film thickness unevenness is 6.5μm
It was a convex part. Moreover, the yield of the surface roughening step was 100%. When this photoreceptor was incorporated into the same electrophotographic apparatus as in Example 1 and image output evaluation was repeated, no problems occurred up to 100,000 copies. This is referred to as Example 3 and the results are shown in Table 1.

<Example 4> In a photoreceptor coated in the same manner as in Example 1, an abrasive particle diameter of 3.0 was applied to the contact area of the cleaning blade.
The surface of this photoreceptor was roughened only with an abrasive of 80.0 μm in diameter, while at the same time, the area where the film thickness deteriorated was roughened only with an abrasive with an abrasive particle size of 80.0 μm. (Rz) is 1.4 μm 1 Minimum and maximum surface roughness are each 0
．． 7μm-1.7μm, and the film thickness unevenness is 4.9μm.
It was a convex shape of m. Moreover, the yield of the surface roughening step was 100%. Then, this photoreceptor was incorporated into an electrophotographic device similar to that in Example 1, and image output evaluation was repeatedly performed.
No problems occurred up to 100,000 sheets. This is referred to as Example 4 and the results are shown in Table 1.

<Comparative Example 1> When an experiment was conducted using the same apparatus as in Example 1 except that the photoreceptor was not polished, the cleaning blade reversed after about 100,000 images were repeatedly produced, and the apparatus stopped working. This was used as Comparative Example 1 and the results are shown in Table 1.

<Comparative Example 2> In a photoconductor coated in the same manner as in Example 1, only the area in contact with the cleaning blade was first coated with an abrasive having an abrasive particle diameter of 9.0 μm, and then an abrasive material having an abrasive particle diameter of 0.5 μm was applied. When the surface was roughened using an abrasive, the average surface roughness (Rz) of this photoreceptor was 1.0 μm, and the minimum and maximum surface roughness were 0.8 μm and 1.2 μm, respectively. However, the area where the film thickness decreased remained a convex portion of 52.3 μm because the surface was not roughened. However, the yield of the surface roughening step was 100%. When this photoreceptor was installed in the same electrophotographic apparatus as in Example 1 and image output evaluation was repeatedly performed, it was found that after 20,000 copies, toner fusion began to occur at the sagging part of the film thickness.
Image defects began to appear after around 30,000 copies. This was treated as Comparative Example 2 and the results are shown in Table 1.

<Comparative Example 3> In a photoreceptor coated in the same manner as in Example 1, after coating the photosensitive layer and before drying, a step of peeling off the portion where the film thickness was reduced using a solvent was provided. The surface of this photoreceptor was roughened only at the area in contact with the cleaning blade, first with an abrasive with an abrasive particle size of 9.0 μm, and then with an abrasive with an abrasive particle size of 0.5 μm. Body surface average surface roughness (R
z) is 1.0μm1 The minimum and maximum surface roughness are each 0.8
μm-1.2 μm, and the film thickness unevenness was 5.5 μm. However, although the yield of the surface roughening step was 100%, the yield of photoreceptor coating was lowered to 88% due to the step of peeling off the film thickness before that. Using this as comparative example 3,
The results are shown in Table 1.

As can be seen from Examples 1 to 4 and Comparative Examples 1 to 3, the surface treatment of the photoreceptor is carried out by selectively using two or more types of abrasives with different abrasive particle diameters depending on the part of the photoreceptor. , the surface can be uniformly roughened, the lubrication duration between the cleaning blade and the photoconductor surface is improved, and the uneven film thickness during photoconductor coating can be reduced or eliminated without reducing the photoconductor manufacturing yield. I know what I can do.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to uniformly roughen the surface without reducing the yield, and it is possible to obtain an excellent image without any cleaning defects.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of an apparatus that can be used in the surface roughening method of the present invention. FIG. 2 is a schematic cross-sectional view for explaining the operation of a cleaning device using a cleaning blade. FIG. 3 is a sectional view showing an example of an electrophotographic photoreceptor treated by the surface roughening method of the present invention. Funeral map

Claims (1)

[Claims] An electrophotographic photosensitive method for roughening the surface of an electrophotographic photoreceptor using a film-like abrasive material, characterized in that two or more types of abrasive materials having different abrasive particle sizes are used depending on the part of the photoreceptor. Body surface roughening method.