JP7375385B2 - Photoconductor drum, image forming device, and photoconductor drum regeneration method - Google Patents

Description

The present invention relates to a photoreceptor drum, an image forming apparatus, and a photoreceptor drum recycling method.

Generally, in an image forming apparatus, an electrostatic latent image is formed on a photoreceptor drum by an optical writing device, the electrostatic latent image is developed as a toner image by a developing device, and the toner image is transferred to a transfer belt. Thereafter, the toner remaining on the surface of the photoreceptor drum is removed by a cleaning device. By repeating the formation of toner images and the removal of toner in this way, scratches and the like may occur on the surface of the photoreceptor drum.

Therefore, a photoreceptor recycling device has been proposed that polishes and recycles the surface of a photoreceptor (for example, see Patent Document 1). In the photoreceptor recycling apparatus described in Patent Document 1, deposits on the surface of the photoreceptor are removed by setting the surface roughness Rmax of the photoreceptor after polishing to 4.5 or less.

However, simply polishing the photoreceptor to reduce its surface roughness may not provide the same characteristics as an unused photoreceptor, so it is desirable to further improve the characteristics of the photoreceptor after polishing. It was rare.

An object of the present invention is to provide a photoreceptor drum that can obtain good characteristics even after polishing, an image forming apparatus equipped with the photoreceptor drum, and a photoreceptor drum regeneration method.

In order to solve the above-mentioned problem, the invention according to claim 1 provides a photosensitive drum in which a photosensitive layer and a protective layer are sequentially laminated on the outer peripheral surface of a hollow cylindrical sleeve member, wherein the surface of the protective layer is , the arithmetic mean roughness Ra defined in JISB0601:2001 is less than 0.03 μm at a cutoff value of 0.25mm, and the arithmetic mean waviness Wa defined in JISB0601:2001 is 0 at a cutoff value of 2.5mm. The photosensitive drum is characterized in that it has a thickness of .05 μm or more.

According to the photoreceptor drum of the present invention, since the arithmetic mean roughness Ra is less than 0.03 μm, even if scratches are formed on the surface due to the use of the photoreceptor drum, the effects of these scratches can be avoided by polishing. can be reduced. Therefore, when cleaning the surface of the photoreceptor drum with the cleaning blade, it is possible to suppress cleaning failures caused by surface scratches, and also to suppress streak-like stains caused by surface scratches during image formation. Further, by having the arithmetic mean waviness Wa of 0.05 μm or more, it is possible to ensure the cleaning characteristics of the cleaning blade, and it is also possible to suppress uneven contact of the cleaning blade. In this way, by reducing surface roughness at a relatively microscopic level and leaving surface undulations at a relatively macroscopic level, it is possible to obtain good characteristics even for the photoreceptor drum after polishing. .

FIG. 1 is a sectional view showing a photosensitive drum according to an embodiment of the present invention. FIG. 3 is a cross-sectional view showing the surface state of the unused photoreceptor drum. FIG. 3 is a cross-sectional view showing the surface state of the photoreceptor drum after use. FIG. 2 is a perspective view showing a polishing device for polishing the photoreceptor drum. FIG. 3 is a cross-sectional view showing the surface state of the photosensitive drum polished by a polishing means having a polishing means having free abrasive grains. FIG. 3 is a cross-sectional view showing the surface state of the photosensitive drum polished by a polishing means having a polishing means having fixed abrasive grains. 7 is a graph showing the relationship between the primary particle system and the average polishing speed when the surface of a photoreceptor drum is polished by a polishing means having agglomerated abrasive grains. 3 is a graph showing the arithmetic mean waviness Wa of the photosensitive drum before and after polishing. 3 is a graph showing the capacitance of a photoreceptor drum before and after polishing.

Hereinafter, each embodiment of the present invention will be described based on the drawings. As shown in FIG. 1, the photosensitive drum 1 of this embodiment includes a hollow cylindrical sleeve member 2, a photosensitive layer 3 laminated on the outer peripheral surface of the sleeve member 2, and a photosensitive layer 3 laminated on the outer peripheral surface of the photosensitive layer 3. A laminated protective layer 4 is provided. That is, the photosensitive layer 3 and the protective layer 4 are sequentially laminated on the outer peripheral surface of the sleeve member 2. The photoreceptor drum 1 is used in image forming devices such as copying machines, facsimile machines, laser printers, and multifunctional devices thereof. An electrostatic latent image is formed on the surface by an optical writing device, and the electrostatic latent image is transferred to toner by a developing device. The image is developed and the toner image is transferred to a transfer belt.

The photosensitive layer 3 is composed of, for example, an undercoat layer, a charge generation layer, and a charge transport layer. The protective layer 4 is made by dispersing filler such as resin in a binder resin such as polycarbonate that constitutes the charge transport layer. The structure and material of the photosensitive layer 3 and the protective layer 4 may be selected as appropriate.

FIG. 2 schematically shows the surface shape of the protective layer 4 on the photosensitive drum 1 in an unused state (new), and FIG. 3 schematically shows the surface shape of the protective layer 4 on the photosensitive drum 1 after being used a predetermined number of times. to show.

As shown enlarged in FIGS. 2 and 3 (see inside the broken line), the use of the photosensitive drum 1 causes surface roughness deterioration due to wear and filming. Further, by using the photoreceptor drum 1, scratches 41 to 43 are formed due to uneven contact of the cleaning blade and developer material. Further, the surface of the protective layer 4 has a undulating shape both before and after the photosensitive drum 1 is used.

The photosensitive drum 1 deteriorated due to use is polished as described below to regenerate the photosensitive drum 1.

FIG. 4 shows a polishing device (polishing device) 100 for polishing the photoreceptor drum 1. As shown in FIG. The polishing device 100 includes a cylindrical elastic member 101 and a polishing film 102 attached to the top surface of the elastic member 101, and is rotated by a power source with the height direction of the cylindrical elastic member 101 as an axial direction. is configured to do so.

The elastic member 101 is made of, for example, foamed urethane, foamed EVA sponge, suede, nonwoven fabric, or the like.

The polishing film 102 has agglomerated abrasive grains as polishing abrasive grains, and functions as a polishing means. Agglomerated abrasive grains are aggregates made up of a large number of fine primary particles, and the large number of primary particles are loosely bonded to each other while forming voids, forming a granular porous body.

In order to obtain such agglomerated abrasive grains, first, they are granulated using a spray dryer to obtain granules (secondary particles) having a particle size of about 1 to 300 μm. Thereafter, the granules are heat-treated to form a porous structure. It is preferable that the agglomerated abrasive grains after the heat treatment have a compressive fracture strength of 20 MPa or less. If the compressive fracture strength is too high, scratches are likely to occur during polishing.

It is preferable that the primary particles of the agglomerated abrasive grains have an average particle size of 4 μm or less. Further, the primary particles are preferably inorganic oxides such as aluminum oxide, zirconium oxide, silicon dioxide, cerium oxide, silicon dioxide, and iron oxide.

Next, the abrasive grains obtained as described above are mixed with liquid urethane resin, methyl ethyl ketone is added as a solvent, the solution viscosity is adjusted, and the mixture is mixed and stirred using a stirrer for about 10 minutes to prepare a mixture. do. Stirring may be performed at room temperature, and the rotational speed may be set to 100 rpm so as not to destroy the abrasive grains. This mixture may be applied onto a substrate (for example, a PET film with a thickness of about 75 μm) using a wire bar coater, and then dried for 1 hour in a constant temperature bath kept at 60° C. to obtain a polished film.

The polishing process is performed by rotating the photosensitive drum 1 by a power source, and by rotating the polishing device 100 by the power source and reciprocating it in the vertical direction in the figure. At this time, the surface of the photoreceptor drum 1 is polished by rotating the polishing film 102 together with the elastic member 101 while biting into the surface of the photoreceptor drum 1 by a certain amount.

A regenerated photosensitive drum can be obtained by polishing the photosensitive drum 1 whose surface of the protective layer 4 has deteriorated after being used a predetermined number of times using the polishing apparatus 100 as described above. The recycled photosensitive drum has an arithmetic mean roughness Ra defined in JISB0601:2001 of less than 0.03 μm at a cutoff value of 0.25 mm on the surface of the protective layer 4, and an arithmetic mean waviness defined in JISB0601:2001. Wa is 0.05 μm or more at a cutoff value of 2.5 mm, and maximum height roughness Rz defined in JISB0601:2001 is 0.5 μm or less at a cutoff value of 0.25 mm. Further, in the reproduced photosensitive drum, the average thickness of the protective layer 4 is 0.2 μm or more.

According to this embodiment, the following effects are achieved. That is, since the arithmetic mean roughness Ra on the surface of the protective layer 4 is less than 0.03 μm, even if scratches 41 to 43 are formed on the surface by using the photoreceptor drum 1, these scratches 41 to 43 can be removed by polishing. 43 can be reduced. Therefore, when cleaning the surface of the photoreceptor drum with the cleaning blade, it is possible to suppress cleaning failures caused by surface scratches, and also to suppress streak-like stains and the like caused by surface scratches during image formation.

Further, by setting the arithmetic mean waviness Wa on the surface of the protective layer 4 to 0.05 μm or more, it is possible to ensure the cleaning characteristics of the cleaning blade and to suppress uneven contact of the cleaning blade. In this way, by reducing surface roughness at a relatively microscopic level and leaving surface undulations at a relatively macroscopic level, it is possible to obtain good characteristics even for the photoreceptor drum after polishing. .

Further, by setting the maximum height roughness Rz of the surface of the protective layer 4 to 0.5 μm or less, new scratches due to polishing can be made less likely to occur.

In addition, since the average thickness of the protective layer 4 is 0.2 μm or more, changes in the electrostatic properties of the photosensitive layer 3 can be suppressed, and the service life of the recycled photosensitive drum 1 can be extended.

By polishing the surface of the protective layer 4 using the polishing film 102 having agglomerated abrasive grains, the arithmetic mean waviness Wa can be reduced to 0 while making the arithmetic mean roughness Ra on the surface of the protective layer 4 after polishing less than 0.03 μm. It can be set to .05 μm or more.

On the other hand, when polishing using a polishing means having free abrasive grains (for example, a soft polishing pad made of nonwoven fabric or sponge), as shown in FIG. (indicated by a broken line), it is possible to maintain the waviness shape and suppress the decrease in the arithmetic mean waviness Wa, but as the polishing progresses, the scratches 41 to 43 also progress, and the deeper scratches among the scratches 41 to 43 may not be able to be removed.

Furthermore, when polishing using a polishing means (for example, abrasive paper) having fixed abrasive grains, as shown in FIG. Wa will decrease.

That is, by polishing using the polishing film 102 having agglomerated abrasive grains as in this embodiment, it is possible to maintain the undulating shape while removing the scratches 41 to 43.

Further, by using agglomerated abrasive grains having an average primary particle diameter of 4 μm or less, it is possible to suppress the occurrence of polishing flaws such as scratches on the surface of the protective layer 4, which is the processed surface. On the other hand, if the average particle size of the primary particles is too large, although the processing efficiency of polishing is improved, polishing flaws such as scratches are likely to occur on the processed surface, and the quality may deteriorate.

In addition, by using agglomerated abrasive grains with a compressive fracture strength of 20 MPa or less, the wear of the abrasive grains gradually progresses during polishing, making it easier to generate new cutting edges, and the surface of the protective layer 4. When polishing, it is possible to improve processing efficiency and quality, and furthermore, it is possible to easily maintain such a state for a long time. On the other hand, if the compressive fracture strength of the agglomerated abrasive grains is too high, new polishing scratches may be created on the surface of the protective layer 4 during polishing, which may lead to a decrease in surface quality.

Further, by using agglomerated abrasive particles whose primary particles are composed of an inorganic oxide, dirt and scratches on the surface of the protective layer 4 can be easily removed.

Note that the present invention is not limited to the embodiments described above, and includes other configurations that can achieve the object of the present invention, and the present invention also includes the following modifications.

For example, in the embodiment described above, the maximum height roughness Rz on the surface of the protective layer 4 is 0.5 μm or less at a cutoff value of 0.25 mm, but the arithmetic mean roughness Ra is set at a cutoff value of 0.25 mm. The maximum height roughness Rz may be greater than 0.5 μm as long as it can be less than 0.03 μm at 25 mm.

Further, in the above embodiment, the average thickness of the protective layer is 0.2 μm or more, but for example, if you want to improve the initial image quality, the average thickness of the protective layer is less than 0.2 μm. You can also use it as

Furthermore, in the embodiment, the agglomerated abrasive grains are those in which the average particle diameter of the primary particles is 4 μm or less, the compressive fracture strength is 20 MPa or less, and the primary particles are composed of an inorganic oxide. The polishing means only needs to have agglomerated abrasive grains that can maintain the undulating shape while removing scratches on the surface of the protective layer 4. The material may be selected appropriately.

In addition, the best configuration, method, etc. for carrying out the present invention have been disclosed in the above description, but the present invention is not limited thereto. That is, although the present invention has been particularly illustrated and described primarily with respect to particular embodiments, there may be other modifications to the embodiments described above without departing from the scope of the invention. It is something that a trader can make various modifications to.

Therefore, the descriptions in which the shapes, materials, etc. disclosed above are limited are provided by way of example to facilitate understanding of the present invention, and are not intended to limit the present invention. Descriptions using names of members that exclude some or all of the limitations on shape, material, etc. are included in the present invention.

[Surface condition before and after polishing]
Using a polishing film in which the average particle diameter of primary particles is 3 μm and the compressive breaking strength is 7.7 MPa, the unused photoconductor drum and the used photoconductor drum are polished, and the arithmetic mean roughness Ra before and after polishing is And the maximum height roughness Rz was measured. For the measurement, Form Talysurf S4C manufactured by the former Teller Hopson Company was used. Furthermore, measurements were taken at four locations (90 degrees apart) in the circumferential direction on the surface of the photoreceptor drum. The results are shown in Table 1.

By using the photosensitive drum, both the arithmetic mean roughness Ra and the maximum height roughness Rz were increased. Further, the arithmetic mean roughness Ra of both the unused photosensitive drum and the used photosensitive drum was reduced by polishing. The maximum height roughness Rz of the unused photosensitive drum became slightly larger due to polishing. Although the maximum height roughness Rz was reduced by polishing the used photoconductor drum, it became a larger value than that of the unused photoconductor drum before polishing.

[Type of polishing means and polishing results]
Using the polishing means of Examples 1 to 5 and Comparative Examples 1 to 3 shown in Table 2, the surfaces of the used photoreceptor drums were polished.

The ultra-precision wrapping film of Comparative Example 1 is a 1200# film from the LAPIKA series manufactured by KOVAX. The ultra-precision wrapping film of Comparative Example 2 is a 10000# film of the LAPIKA series manufactured by KOVAX, and has a finer grain size than Comparative Example 1. The polishing cloth pad of Comparative Example 3 was suede type Safin 018-3 manufactured by Fujimi Corporation, and the alumina slurry was abrasive grains manufactured by Fujimi Corporation with an average particle size of 0.5 μm at a weight ratio of 5 wt%. It is mixed with water. In Comparative Example 3, alumina slurry was supplied onto the polishing cloth pad at a supply rate of 20 cc/min during polishing.

Table 3 shows the results of polishing using the polishing means of Examples 1 to 5 and Comparative Examples 1 to 3.

In all of Examples 1 to 6, it was possible to suppress the generation of new scratches due to polishing. In particular, in Examples 1 to 4, the generation of new scratches due to polishing could be suppressed. In Comparative Example 1, new scratches were generated due to polishing. The occurrence of new scratches was visually evaluated.

In all of Examples 1 to 6, scratches caused by using the photoreceptor could be removed. In both Comparative Examples 2 and 3, it was not possible to remove scratches caused by using the photoreceptor.

That is, in any of Examples 1 to 6, it was possible to suppress the generation of new scratches due to polishing and to remove scratches generated by using the photoreceptor, and in Comparative Examples 1 to 3, I couldn't do both. In any of Examples 1 to 6, the arithmetic mean roughness Ra was less than 0.03 μm at a cutoff value of 0.25 mm, and the arithmetic mean waviness Wa was 0.05 μm or more at a cutoff value of 2.5 mm. became.

Table 4 shows the maximum height roughness Rz when unused photosensitive drums were polished using the polishing means of Examples 1 to 6.

There was a tendency that the larger the average particle diameter of the primary particles, the larger the maximum height roughness Rz, and the larger the compressive fracture strength, the larger the maximum height roughness Rz.

[Average particle size and polishing efficiency]
The average polishing speed (polishing efficiency) was evaluated when polishing was performed using polishing means with different average particle diameters of primary particles while keeping the compressive fracture strength approximately constant (8 Mpa). The results are shown in FIG. The larger the average particle size of the primary particles, the higher the polishing efficiency, and preferable polishing efficiency was obtained when the average particle size was 3 μm or more.

[Change in arithmetic mean waviness due to polishing]
The photosensitive drum after use was polished using the polishing means of Example 3, and the arithmetic mean waviness Wa before and after polishing (before and after regeneration) was measured. The results are shown in FIG. In all samples, the arithmetic mean waviness Wa was reduced by polishing, but it remained 0.05 μm or more even after polishing.

[Thickness of protective layer after polishing]
The used photoreceptor drum was polished using the polishing means of Example 3 so that the average thickness of the protective layer was 0.2 μm. When such a polished photosensitive drum was installed in an image forming apparatus and a life test was performed, good results were obtained.

[Change in capacitance due to polishing]
The used photoreceptor drum was polished using the polishing means of Example 3, and the capacitance of the surface of the photoreceptor drum 1 was measured before and after the polishing. The results are shown in FIG. Although the capacitance decreased due to polishing, no change that would affect the quality was observed.

1 Photosensitive drum 2 Sleeve member 3 Photosensitive layer 4 Protective layer 100 Polishing device (polishing means)

Japanese Patent Application Publication No. 2002-351098

Claims (5)

A photoreceptor drum recycling method for generating a photoreceptor drum by performing a polishing treatment on a used photoreceptor drum, the method comprising:
In the polishing process, the surface of the protective layer is polished using a polishing means having agglomerated abrasive grains as polishing abrasive grains,
The photoreceptor drum is a photoreceptor drum in which a photoreceptor layer and a protective layer are sequentially laminated on the outer peripheral surface of a hollow cylindrical sleeve member,
The surface of the protective layer has an arithmetic mean roughness Ra defined in JISB0601:2001 of less than 0.03 μm at a cutoff value of 0.25 mm, and an arithmetic mean waviness Wa defined in JISB0601:2001 at a cutoff value of 0.25 mm. A method for recycling a photoreceptor drum, wherein the photoreceptor drum is characterized in that the diameter is 0.05 μm or more at a value of 2.5 mm . The photosensitive drum according to claim 1 is characterized in that the surface of the protective layer has a maximum height roughness Rz defined in JISB0601:2001 of 0.5 μm or less at a cutoff value of 0.25 mm. The method for regenerating a photoreceptor drum according to claim 1. 3. The photoreceptor drum recycling method according to claim 1, wherein the photoreceptor drum has an average thickness of the protective layer of 0.2 μm or more. The photosensitive method according to any one of claims 1 to 3, characterized in that the agglomerated abrasive grains are those whose primary particles have an average particle diameter of 4 μm or less and a compressive fracture strength of 20 MPa or less. How to play body drums. 5. The method for regenerating a photoreceptor drum according to claim 1, wherein the agglomerated abrasive grains include primary particles composed of an inorganic oxide.

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