JPH02139563A - Surface roughening method for organic electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE:To roughen a surface of a photosensitive body uniformly in a short time by grinding a surface of a photosensitive body with a high relative grinding velocity of an abrasive in an initial stage of grinding and then with a low relative grinding velocity. CONSTITUTION:In a stage of grinding a surface of a photosensitive body 1 having an org. photosensitive layer formed thereon, to obtain a roughened surface, a relative grinding velocity of a film abrasive 2 contacting with the surface of the photosensitive body is increased in an initial grinding stage, and then decreased thereafter. By this method, the roughening of the surface can be performed uniformly in a short time, and occurrence of insufficient cleaning due to inversion of cleaning blades at shallow parts of roughening or due to a breakage of edge, or generation of defects such as flaws in a pattern at deep parts of roughening, etc., can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an organic electrophotographic photoreceptor, and more particularly, to a method for obtaining an organic electrophotographic photoreceptor with good printing properties and image characteristics. This invention relates to a surface roughening method for organic electrophotographic photoreceptors.

[Conventional technology]

Generally, in electrophotographic processing, a cycle consisting of at least the steps of charging, image exposure, development, transfer, and cleaning is repeatedly performed on nine electrophotographic photoreceptors. In I#, the cleaning process for removing residual toner on the photoreceptor after the transfer process is an important step to always obtain a clear image.

As a method for this cleaning, the following two-part method is usually used. The first method is to press a 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 falling out and removing residual toner. This is a method of scraping it off. FIG. 2 is a schematic cross-sectional view showing a typical example of a cleaning device using such a leaning blade. The cleaning device 7 is arranged close to a cylindrical photoreceptor 8 rotating in the direction of arrow A. Then, apply one edge of one end of the cleaning blade 9 attached to the cleaning device to the surface of the photoreceptor 8, either in one direction counter to the rotational direction of the photoreceptor as shown in the figure, or in the opposite direction. The remaining toner is scraped off by pressing in the forward direction shown in the figure (it is known that the cleaning performance is better in the counter direction (A). 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, cleaning using a rubber blade is cheaper and easier to design, and cleaning using a cleaning blade is currently the mainstream. Especially when performing natural color development, the three primary colors of magenta, cyan, and yellow,
A/L, since natural colors are produced by layering four colors including black, the amount of toner used is much larger than in normal one-color development. It is best to use a pressure cleaning method.

However, the cleaning blade that exhibits excellent cleaning performance has a drawback in that the cleaning blade tends to reverse due to 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 the toner particle size is made uniform and minute toner particles are removed to improve image quality, the lubricity caused by the toner particles entering the gap between the cleaning blade and the photoreceptor surface is reduced. (The cleaning blade should be rotated by ° to prevent it from fading.)
It becomes easier to form layers.

In addition, when performing natural color development, toner of magenta, cyan, and yellow or four colors including black is used three or four times to produce one image.
Since development is performed twice, a large load is placed on the cleaning blade, which tends to cause the cleaning blade to reverse and further damage the edges.

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, the present applicant previously proposed in Japanese Patent Application No. 1 Sho 62-256769 that the surface of the photoreceptor should be made rough in advance, which would lead to a decrease in image quality. We proposed a method to prevent cleaning defects caused by such problems. The roughening state of the surface of the photoreceptor is expressed by the 10-point average roughness (Rz) measurement method defined in 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 O13 to 2.0 μm. When the maximum value is as large as 5.0 μm, streak-like defects tend to appear in the image.

Furthermore, when the minimum value is smaller than 0.3 μm, the friction between the IJ-ning blade and the photoreceptor surface is hardly alleviated, and the effect of roughening the photoreceptor surface is not observed. The maximum value, average value and minimum value of 0.3~
If it is within the range of 5.0 μm, it will reduce the contact area between the photoreceptor surface and the cleaning blade, and it will also reduce the contact area between the photoreceptor surface and the cleaning blade, and also prevent particles with a small particle size (# grains of 5 μm or less) contained in the toner. The shavings (less than 1 μm) on the surface of the photoconductor that have been scraped off during use are absorbed into the gap between the photoconductor surface and the cleaning blade, making it easier to maintain lubricity. It is possible to prevent cleaning failures due to blade inversion, etc.

On the other hand, as a method for roughening the surface of a photoreceptor, there is
Mechanical polishing methods such as the sand blasting method using brushes and abrasive materials as described in Japanese Patent Application Laid-open No. 3-92133 and Japanese Patent Application Laid-Open No. 57-94772; As described in the publication, there is a method of making the surface look like orange skin by drying conditions during coating, a method of exposing it to a solvent, and a method of forming the surface layer on the surface layer as described in JP-A-52-26226. There is a method in which powder particles are added in advance and coated 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. It's the cutting powder on the surface of the photoreceptor that is generated by mechanical polishing! This is because it acts 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.
This is because in the case of a film-like abrasive material, there is almost no embedding, which causes pinholes and deteriorates the electrophotographic properties.

[Problem to be solved by the invention]

However, in the conventional mechanical polishing method in which the surface of the photoconductor is pressure-polished with an abrasive material to make it rough, the rough surface of the same photoconductor cannot be polished due to differences in the contact state of the abrasive material, the contact pressure, and the polishing speed. It is very difficult to control the surface roughening state because the surface roughening state is uneven, and in shallow areas where the surface roughening state is shallow, the friction between the cleaning blade and the photoreceptor is not alleviated and busy cleaning is required. There were drawbacks such as blade inversion and edge loss, and image defects in the form of scratch patterns on images in deeply roughened areas. Furthermore, even if it is possible to uniformly roughen the surface, there is a drawback that it takes a long time to do so.

SUMMARY OF THE INVENTION An object of the present invention is to provide an organic 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 uniformly roughen the surface of an organic electrophotographic photoreceptor within a predetermined range in a short time to prevent IJ + coating defects. It is to provide law.

[Means to solve the problem]

As a result of intensive studies on roughening the surface of a photoreceptor, the present inventors have discovered a method for roughening the surface of an organic electrophotographic photoreceptor using a film-like abrasive. By changing the relative polishing speed to the contact surface to be fast at the beginning and then slow, it is preferable that the relative polishing speed is from 1.0 m/sec to 5000 twa,
Must be used within the range of 7 seconds. Therefore, JIS standard BO6
The maximum value, average value, and minimum value (hereinafter referred to as A
A uniform rough surface condition in which the maximum surface roughness, average surface roughness, and minimum surface roughness are all within the range of 0.3 to 5.0 Am can be obtained in a short time, We have discovered that cleaning defects can be prevented.

That is, the present invention includes a method for roughening the surface of an organic electrophotographic photoreceptor using a film-like abrasive material, in which the relative polishing speed of the abrasive material to the surface in contact with the photoreceptor is initially increased. It is characterized by a slow change after that.

In a method of roughening the surface of an organic electrophotographic photoreceptor using a film-like abrasive material, roughening (polishing) of the surface of the photoreceptor
Initially, the surface has low abrasion resistance, but after the surface has become rough to some extent, the unevenness of the surface becomes more likely to catch the abrasive particles of the abrasive material, making it easier to abrade, and if the relative polishing speed is high, the rough surface becomes rough. The two points are that when the relative polishing speed is slow, it is difficult to roughen the surface, but it is possible to roughen the surface uniformly. In view of this, the essence of the present invention is to first perform polishing at a high relative polishing speed, and then reduce the speed to achieve a uniform surface.

In implementing the surface roughening method of the present invention, an apparatus schematically shown in cross section in FIG. 1 can be used as an example. The organic electrophotographic photoreceptor 1 is rotated clockwise or counterclockwise. On the other hand, the film-like abrasive material 2 is passed from the feed roller 3 to the take-up roller 5 via the Dem pressure roller 4 which is in pressure contact with the electrophotographic photoreceptor at the arrow direction 6.
move it in the direction of At this time, the film-like abrasive material 2 is rubbed on the surface of the electrophotographic photoreceptor 10 at the position of the presser 4. In the present invention, the relative polishing speed based on the difference between the surface speed of the electrophotographic photoreceptor 10 and the moving speed of the film-like abrasive material 2 is preferably set to 1. Within the range of 0/sec to 5000w/sec, the speed is initially increased and then the speed is decreased.

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 organic 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. 1
1 is preferably a laminated photosensitive layer functionally separated into a charge generation layer 12 and a charge transport layer 13.

The conductive support 10 may be a metal such as aluminum, aluminum alloy, or stainless steel, or a metal coated with a conductive substance alone or together with a suitable binder to provide a conductive layer, or a conductive treated plastic or paper. Conventionally known materials such as those molded into a drum shape or sheet shape can also be used.

The charge generating layer 12 contains a charge generating substance such as an azo pigment, a quinone pigment, a quinocyanine pigment, (a rylene pigment, an indigo pigment, a phthalocyanine pigment), a polyvinyl butyral, -
It can be formed by being dispersed in a binding resin such as styrene, acrylic resin, polyester, polyvinyl acetate, or polycarbonate, or it can be formed as a vapor deposited film using a vacuum evaporation apparatus. The preferred film thickness is 0
．． 01-3 μm.

The charge transport layer 13 is made of a charge transport material such as a styrene compound, a hydrazone compound, a triarylamine compound, a Cal/J zole compound, an oxazole compound, or a pyrazoline compound, polyarylate, polystyrene, acrylic resin, polyester, It can be formed by being dispersed in a binder resin such as I recarbonate. The preferred film thickness is 10 to 30 μm. Further, as a structure of the photosensitive layer 11, a charge generation layer 12 may be formed on the charge transport layer 13, and furthermore, the photosensitive layer 11 may be formed of a monolayer containing the above-mentioned charge generation substance and charge transport substance in the same layer. Even if it is a single layer type.

Further, 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 adhesion and barrier properties.

The organic 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 grade that is brought into contact with the photoreceptor in one direction.

<Example> An 80φ x 360 mm aluminum cylinder was used as a support, and a methanol solution of soluble nylon (6-66-610-12 quaternary nylon copolymer) was applied by dip coating to form a 1 μm thick undercoat. Layers were set up.

Next, 10 parts (!1 part, the same applies hereinafter) of a disazo pigment with the following structural formula, polyvinyl butyral (butyralization degree 68%,
5 parts of number average molecular weight (ft20,000) and 50 parts of cyclohexanone were dispersed for 20 hours in a sand mill using lφ glass beads. Add 70 to 1 methyl ethyl ketone to this dispersion.
2o (add the appropriate amount and apply it on the undercoat layer to a film thickness of 0.1μ)
A charge generation layer of m was formed.

Next, 10 parts of bisphenol type 2/Liquor & Ney) (viscosity average molecular weight 30,000) and 10 parts of a todracine compound having the following structural formula were dissolved in 65 parts of monochlorobenzene, and this solution was dip-coated on the charge generation layer. and 18 μm
A thick charge transport layer was formed. The average surface roughness of this photoreceptor was 0.0 μm.

Using the apparatus shown in Fig. 1, the surface of the photoreceptor prepared by the above method was first polished for 10 seconds at a relative polishing rate of 3000 ssi/sec, and then for 10 seconds at a relative polishing rate of 2.0 m/sec. The average surface roughness (Rz) of the photoreceptor surface was 1.0 μm, and the minimum and maximum surface roughnesses were 0, 8 μm, and 1.2 μm, respectively. This photoreceptor is charged, image exposed, developed, transferred and f
Cleaning with a blade (linear pressure 111I/cM)
When the image forming apparatus was incorporated into an electrophotographic apparatus (NP-352!S, manufactured by Canon) and repeatedly evaluated for image output, no problems occurred until 10,000 images were printed. This is Example 1 and the results are shown in Table 1.

<Examples 2 and 3> Example 11C Noisy, relative polishing rate of 5 ooo / sec.
When the surface of the photoreceptor was polished using the same apparatus and photoreceptor except that the surface was polished for 25 seconds at a relative polishing speed of 1.0 m/s, the average surface roughness of the photoreceptor surface was The surface roughness was 1.2 μm, and the minimum and maximum surface roughness were 0.9 μffl and 81.5 μm, respectively.

In addition, in Example 1, the same equipment and photoreceptor were used, except that the surface was polished for 5 seconds at a relative polishing speed of 4000 m/sec, and then for 25 seconds at a relative polishing speed of 1.5 m/sec. When the surface of the photoreceptor was polished, the average surface roughness of the photoreceptor surface was 1.1 μm, and the minimum and maximum surface roughness were 0.8 μm and 1.3 μm, respectively. Both photoreceptors were tested. When the image forming apparatus was incorporated into the same electrophotographic apparatus as in Example 1 and repeatedly evaluated for image output, no problems occurred in any case up to 100,000 sheets. Among these, the former is referred to as Example 2, and the latter is referred to as Example 3, and the results are shown in Table 1.

<Comparative Example 1> When an experiment was conducted in the same manner as in Example 1 using the same apparatus and photoconductor except that the photoconductor was not polished, the cleaning blade reversed after about 10 images were repeatedly produced. , the device has stopped working. This was taken as Comparative Example 1, and the results are shown in Table 1.

Comparative Examples 2, 3.4) In Example 1, the relative polishing speed was 1.0 m/sec, 7
The same apparatus and photoreceptor were used, except that K was set to 00ffi1/sec and 5000 positions/sec.
The average, maximum and minimum surface roughness of the photoreceptor surface is 0.3.
When the surface was polished to fall within the range of μm or more and 5.0 μm or less, it took 80 minutes, 40 minutes, and 45 minutes, respectively. The results are shown in Table 1 as Comparative Examples 2, 3, and 4, respectively.

As shown in Examples 1 to 3 and Comparative Examples 1 to 4, the surface treatment of the photoreceptor was carried out by changing the relative polishing rate of the abrasive to the contact surface of the organic electrophotographic photoreceptor).
It can be seen that the surface can be uniformly roughened in a short time, and that the lubricity between the cleaning blade and the photoreceptor surface is improved.

〔Effect of the invention〕

As explained above, in order to prevent the cleaning blade from turning over or chipping the edges due to the friction between the cleaning blade and the photoreceptor surface that occurs in the electrophotographic process using a cleaning means using a rubber blade, the surface of the photoreceptor is prepared in advance. Although a polishing method has been proposed, it is difficult to control the roughening state of the photoreceptor surface, and it takes a long time to achieve uniform roughening. According to the above, the surface of an organic electrophotographic photoreceptor can be uniformly roughened within a predetermined range in a short time, and therefore, cleaning defects and image defects can be prevented. can be provided.

[Brief explanation of the drawing]

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 organic electrophotographic photoreceptor treated by the surface roughening method of the present invention. In the figure, 1 is an organic electrophotographic photoreceptor, 2 is a film-like abrasive material, 3 is a feed roller, 4 is a press roller, 5 is a take-up roller, 7 is a cleaning device, 8 is a photoreceptor,
9 is a cleaning blade, 10 is a conductive support, 11
12 is a photosensitive layer, 12 is a charge generation layer, and 13 is a charge transport layer. Agent Patent Attorney Seki Yamashita

Claims (1)

[Claims] In a method of roughening the surface of an organic electrophotographic photoreceptor using a film-like abrasive material, the relative polishing speed of the abrasive material to the surface in contact with the photoreceptor is initially increased and then changed to a slower rate. Characteristic surface roughening method for organic electrophotographic photoreceptors.