JP2702252B2 - Surface roughening method for organic electrophotographic photoreceptor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an organic electrophotographic photoreceptor,
The present invention relates to a method for roughening the surface of an organic electrophotographic photosensitive member for obtaining an organic electrophotographic photosensitive member having good cleaning properties and image characteristics.

[Related Art] Generally, in an electrophotographic process, a cycle including at least steps of charging, image exposure, development, transfer and cleaning is repeatedly performed on an electrophotographic photosensitive member. In particular, the cleaning step for removing the residual toner on the photoreceptor after the transfer step is an important step for always obtaining a clear copy image.

As the cleaning method, the following two methods are usually used. The first is a method in which a rubber plate-shaped member called a cleaning blade is pressed against a photoreceptor to eliminate a gap between the photoreceptor and the cleaning blade, to prevent toner from slipping out, and to scrape off residual toner. is there. FIGS. 1 and 2 are schematic sectional views showing a typical example of a cleaning device using such a cleaning blade. The cleaning device 1 is located close to a cylindrical photosensitive member 2 which rotates in the direction of arrow A. One edge of one end of the cleaning blade 3 attached to the cleaning device is placed on the surface of the photoreceptor 2 in the counter direction with respect to the rotation direction of the photoreceptor as shown in FIG. 2, or by pressing in the forward direction to scrape off the residual toner (it is known that the cleaning property is better in the counter direction). The second is
This is a method in which the roll of the fur brush is rotated so as to be in contact with the surface of the photoreceptor, and the remaining toner is wiped off or knocked down. Of these two methods, rubber blades are cheaper and easier to design, so cleaning using a cleaning blade is currently the mainstream. Particularly when performing natural color development, magenta,
Since natural colors are produced by superimposing three primary colors of cyan and yellow, or four colors including black, the amount of toner used is much larger than in normal one-color development. It is optimal to use a cleaning method in which pressure is applied.

However, the counter-direction cleaning blade exhibiting excellent cleaning properties has a drawback that the cleaning blade is likely to be inverted because of a large frictional force with the photoconductor. This reversal of the cleaning blade is a development in which the cleaning blade 3 in the counter direction shown in FIG. 1 is warped in the direction of movement of the photoconductor, that is, in the direction opposite to the counter direction as indicated by 3a.

This phenomenon of the reversal of the cleaning blade is more likely to occur when the surface of the photoconductor is hardened, that is, hardly scraped to extend the life of the photoconductor. In addition, when the toner has a uniform particle diameter to improve the image quality and fine toner is removed, the lubricity caused by the toner entering the gap between the cleaning blade and the surface of the photoconductor is reduced. Since the cleaning blade becomes thinner, reversal of the cleaning blade is more likely to occur.

In the case of performing the natural color phenomenon, three or four times of development is performed using a toner of three colors of magenta, cyan, and yellow, or four colors including black to produce one image. Therefore, the load applied to the cleaning blade is increased, so that the cleaning blade is likely to be inverted and the edge portion is more likely to be lost.

Further, when the surface layer of the photoreceptor is made of an organic material, the frictional resistance between the cleaning blade and the surface of the photoreceptor is increased as compared with the surface of the inorganic material, and in particular, the reversal of the cleaning blade and the loss of the edge portion are more likely to occur. .

Therefore, the applicant of the present invention has previously disclosed in Japanese Patent Application No. 62-25669 a cleaning method in which the surface of the photoreceptor is roughened in advance without deteriorating the image quality without reversing the cleaning blade or losing the blade edge. A method to prevent defects was proposed. The surface roughness of the photoconductor
The maximum value, the average value and the minimum value are preferably in the range of 0.3 to 5.0 μm, more preferably 0 to 10 in terms of the 10-point average roughness (R _Z ) measurement method defined in JIS standard B0601. .
It is in the range of 3 to 2.0 μm. If the maximum value is larger than 5.0 μm, streaks tend to appear on the image as image defects. When the minimum value is smaller than 0.3 μm, the friction between the cleaning blade and the surface of the photoconductor is hardly partially reduced, and the effect of roughening the surface of the photoconductor is not recognized. If the above maximum value, average value and minimum value are in the range of 0.3 to 5.0 μm, the contact area between the photosensitive member surface and the cleaning blade is reduced, and the fine particle diameter slightly contained in the toner (Almost 5 μm
The cleaning blade can be easily lubricated when the shavings (approximately 1 μm or less) of the photoreceptor surface scraped off by use penetrate into the gap between the photoreceptor surface and the cleaning blade appropriately. It is possible to prevent a cleaning failure due to reversal of the image.

On the other hand, Japanese Patent Application Laid-Open
As described in JP-A-53-92133 and JP-A-57-94772, a mechanical polishing method such as a sand plast method using a brush or an abrasive is disclosed in JP-A-53-92133.
JP-A No. 52-26226 discloses a method of forming the surface into a yuzu-skin under the drying conditions at the time of coating, a method of exposing to a solvent, and a surface layer as described in JP-A-52-26226. A method in which powder particles are added in advance to form a coating and the surface is roughened. Among them, the method of mechanical polishing is most preferable in terms of increasing 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 work as a lubricant. Further, among mechanical polishing, a method using a film-like abrasive is more preferable. The reason is that in the case of the sand blast method, etc., the abrasive is easily embedded in the organic electrophotographic photoreceptor, causing a pinhole or deteriorating the electrophotographic characteristics. This is because there is almost no embedding.

[Problems to be solved by the invention]

However, if the shavings generated by the surface roughening treatment have been cleaned or removed by other means after the treatment, or under particularly severe conditions (temperatures of 35 ° C or higher,
When the surface is roughened at a humidity of 80% or more, the surface is roughened but the lubricant (fine powder) does not exist at all due to the high temperature and high humidity (the fine powder aggregates and becomes coarse). Therefore, when the use of the photoreceptor is started, a cleaning failure such as reversal of the cleaning blade or application of a blade edge may occur.

As a method of the surface roughening treatment, a rod-like or brush-like treatment can be considered. However, as the treatment is repeated, clogging and contamination become severe, and it becomes difficult to obtain a target surface roughness.

Further, in the roughening process, when the environment is high temperature and high humidity, the shaved powder of the organic photoreceptor generated during polishing is agglomerated and agglomerated, losing its effect as a polishing aid. I will be. Further, in the case of low temperature and low humidity, the shaved powder of the organic photoreceptor generated during polishing is frictionally charged and scattered, and in this case, there is a disadvantage that the effect as a polishing aid is lost. .

SUMMARY OF THE INVENTION An object of the present invention is to provide an organic electrophotographic photoreceptor capable of preventing poor cleaning and damage on an image due to reversal of a cleaning blade or loss of an edge portion in any environment. is there.

[Means for solving the problem]

The present invention provides a method for roughening the surface of an organic electrophotographic photoreceptor using an abrasive, wherein a film-like abrasive is used as the abrasive, at a temperature of 15 to 25 ° C. and a relative humidity of 15 to 55%.
Roughening the surface of the organic electrophotographic photoreceptor in an environment of
It is characterized in that shavings of the photoreceptor generated by this roughening are left on the surface of the photoreceptor.

In addition, by using a film-like abrasive as the above-mentioned abrasive, it is possible to always use a polished surface in a new state, so that it is possible to always provide a surface having the same roughness.

In addition, the temperature is between 15 ° C and 25 ° C, and the relative temperature is between 15% and 55%
By performing the surface roughening treatment under the following environment, the shavings of the photoreceptor generated by polishing work effectively as a polishing aid, and the shavings show an effect as a lubricant at the start of use of the photoreceptor.

The use of a film-like abrasive material has the advantage that the apparatus can be designed to be compact and the polishing effect can be stably maintained. Furthermore, organic electrophotographic photoreceptors that operate as photoconductors are often unstable to strong light, so even when roughening, they can be processed in the dark or under light that the photoreceptor does not absorb. desirable.

Examples of the above film-like abrasive which can be used in the practice of the present invention include those in which fine particles such as aluminum oxide, silicon carbide, chromium oxide, and diamond are applied to a film such as polyester and fixed.

The organic electrophotographic photoreceptor treated by the surface roughening method of the present invention is obtained by laminating an organic photosensitive layer on a conductive support, and this photosensitive layer is preferably used as a charge generation layer and a charge transport layer. It is a laminated type photosensitive layer with separated functions.

Metals such as aluminum, aluminum alloys, stainless steel, etc., conductive materials applied alone or with an appropriate binder to provide a conductive layer, or conductive-treated plastic or paper as a conductive support, or in the form of a drum or sheet Any of those conventionally known, such as those molded into, can be used.

The charge generation layer is made of a charge generation substance such as an azo pigment, a quinone pigment, a quinocyanine pigment, a perylene pigment, an indigo pigment, a phthalocyanine pigment, and a binding resin such as polyvinyl butyral, polystyrene, an acrylic resin, polyester, polyvinyl acetate, and polycarbonate. , And can also be formed as a deposited film by a vacuum deposition apparatus. Preferred film thickness is 0.01
３3 μm.

The charge transport layer is formed by combining 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 with a polyarylate, polystyrene, acrylic resin, polyester, or polycarbonate. It can be formed by being dispersed and contained in an adhesive resin. The preferred film thickness is 10 to 30 μm. Further, as a constitution of the photosensitive layer, a charge generation layer may be formed on the charge transport layer. Further, the photosensitive layer is a single layer type in which the above-mentioned charge generation substance and the charge transport substance are contained in the same layer. You may.

Further, an intermediate layer such as an undercoat layer may be provided between the conductive support and the photosensitive layer in order to improve adhesion and barrier properties.

The organic electrophotographic photoreceptor whose surface is roughened by the method of the present invention is used in an electrophotographic process having a cleaning means with a rubber blade abutted on the photoreceptor in a counter direction.

Example 1 An aluminum cylinder having a diameter of 80 mm x 360 mm was used as a support, and a 5% methanol solution of soluble nylon (6-66-610-12 quaternary nylon copolymer) was immersed and applied to the support.
An undercoat layer having a thickness of μm was provided.

Next, the structural formula 10 parts of a disazo pigment (parts by weight, hereinafter the same), polyvinyl butyral (butyralization degree: 68%, number average molecular weight: 2000)
0) 5 parts and 50 parts of cyclohexanone were dispersed in a sand mill using 1φ glass beads for 20 hours. To this dispersion, 70 to 120 parts (as appropriate) of methyl ethyl ketone was added and applied onto the undercoat layer to form a 0.1 μm-thick charge generation layer.

Next, 10 parts of bisphenol Z-type polycarbonate (viscosity average molecular weight 30,000) and the structural formula 10 parts of the hydrazone compound was dissolved in 65 parts of monochlorobenzene, and this solution was applied onto the charge generation layer by dip coating to obtain 18 parts.
A μm thick charge transport layer was formed. The average surface roughness of this photoreceptor was 0.0 μm.

The photoreceptor prepared by the above method was heated at a temperature of 23 ° C and a relative humidity of 50.
%, The surface of the photoreceptor was polished with a film-like abrasive having a film grain size of 6.0 μm (wrapping film manufactured by Sumitomo 3M Limited) under an environment of a light quantity of 50 lux. The surface average surface roughness (R _Z ) was 0.8 μm. Yes, minimum surface roughness 0.5μ
m, and the maximum surface roughness was 1.4 μm. While holding the shavings generated in the polishing process of this photoconductor, charging, image exposure,
Electrophotographic equipment (NP-35) with development, transfer and cleaning with polyurethane rubber blade (linear pressure 11g / cm)
25, manufactured by Canon Inc.), and repeated image evaluation was performed. As a result, high quality images could be maintained up to 100,000 sheets without any problem.

Comparative Example 1 Polishing was carried out in the same manner as in Example 1, and finally this photoreceptor was put into methyl alcohol to remove shavings generated in the polishing step, and ultrasonic waves were applied thereto, and washed for 1 minute, and then 100 ° C.
For 10 minutes. The photoreceptor thus obtained was incorporated into the same electrophotographic apparatus as in Example 1 and repeated image output evaluation was performed. As a result, the polyurethane go blade was inverted with the start of rotation of the photoreceptor.
The photoconductor can no longer be rotated.

Example 2 The same apparatus as in Example 1 was used, except that an abrasive having a film grain size of 9 μm was used instead of the abrasive having a film grain size of 6 μm.
When the treatment was performed in an environment of a temperature of 15 ° C. and a relative humidity of 15%, the surface average surface roughness (R _Z ) was 1.0 μm, the minimum surface roughness was 0.6 μm, and the maximum surface roughness was 1.7 μm. . While maintaining the shavings generated in the polishing process of this photoreceptor, it was incorporated into the same electrophotographic apparatus as in Example 1 and repeatedly evaluated for image output. As a result, it was possible to obtain a high quality image without any problem up to 100,000 sheets. I was able to maintain it.

Comparative Examples 2, 3, 4, and 5 Polishing was performed using the same apparatus as in Example 2 while changing the processing environment to the temperature and humidity environment shown in Table 1.

Example 3 Using the same apparatus as in Example 1, exactly the same processing was performed three times in succession. Table 2 shows the results.

Comparative Example 6 In the same manner as in Example 3, the treatment was performed three times continuously using a cylindrical abrasive instead of the film-like abrasive of Example 1. Table 3 shows the results.

If the polishing process is repeated in this manner, the surface cannot be roughened, and blade reversal occurs.

〔The invention's effect〕

As described above, the presence of the shavings of the photoreceptor that has undergone the polishing treatment has the effect of preventing blade reversal. Also, by using a film-like abrasive for the polishing process, a stable polished surface could always be obtained. Furthermore, by performing the treatment in an environment where the temperature is 15 ° C. or more and 25 ° C. or less and the relative humidity is 15% or more and 55% or less, an efficient and stable polished surface could be obtained. The use of a film-like abrasive also has the effect of enabling the polishing apparatus to be designed compact.

[Brief description of the drawings]

1 and 2 are schematic diagrams illustrating a known cleaning device. FIG. 1 shows the arrangement of cleaning blades in a counter direction, and FIG. 2 shows the arrangement of cleaning blades in a forward direction. 1 is a cleaning device, 2 is a photoreceptor, 3 is a cleaning blade, and 3-a is an inverted state of the cleaning blade.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Harumi Sakami 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-1-99060 (JP, A) JP-A-61 −219960 (JP, A)

Claims (1)

(57) [Claims] 1. A method for roughening the surface of an organic electrophotographic photoreceptor using an abrasive, wherein a film-like abrasive is used as the abrasive, at a temperature of 15 to 25 ° C. and a relative humidity of 15 to 55%.
Roughening the surface of the organic electrophotographic photoreceptor in an environment of
A method of surface roughening an organic electrophotographic photosensitive member, wherein shavings of the photosensitive member generated by the surface roughening are left on the surface of the photosensitive member.