JPH05224575A - Drum unit - Google Patents

Abstract

PURPOSE:To obtain always good and uniform images at the time of starting the use of a photosensitive body by incorporating conductive powder and/or conductive resin into a cleaning blade and/or film sheet. CONSTITUTION:This drum unit has at least the electrophotographic sensitive body 1 and the cleaning blade 3 and/or the film sheet 4 in contact with the photosensitive body 2. The cleaning blade 3 and/or the film sheet 4 contains the conductive powder and/or the conductive resin in such a case. Namely, rubber materials and the foamed bodies thereof as well as foamed bodies of various kinds of synthetic resins are used as the constituting materials of the cleaning blade 3 and/or the film sheet 4. The potential difference between the surface of the photosensitive body 2 and the cleaning blade 3 and the film sheet 4 is hardly generated even if the friction between the photosensitive body 2 and the cleaning blade 3 and the film sheet 4 by the vibration and impact at the time transportation and vibration arises. The generation of static electricity is thus prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drum unit including an electrophotographic photosensitive member and a cleaning unit having a cleaning blade and / or a film seal. The present invention relates to a drum unit capable of always obtaining a good and uniform image.

[0002]

2. Description of the Related Art Conventionally, electrophotographic copying machines, laser beam printers, LED printers, LCD printers, C
For electrophotographic devices such as RT printers,
In order to improve serviceability, a unit in which process devices are integrated has been put into practical use. The integrated process device includes a charging device, a developing device, and a cleaner. Among them, at least in the unit where the cleaner and the photoconductor are integrated, the photoconductor and the cleaner are in contact with each other at a fixed position until they are used in the market. In particular, the cleaning blade, the film seal, and the photoconductor are kept in pressure contact with each other from the time of manufacturing the unit to the use by the user. In that case, a so-called memory effect occurs, in which the cleaning blade and the film seal contacting portion of the memory remain on the photoconductor due to physical effects such as impact and vibration during long-term transportation and storage processes, resulting in image defects. There's a problem.

[0003]

The memory effect on the photoconductor as described above is characteristic of the charge generating material, and is suitable for pigment-dispersed photoconductors, particularly organic photoconductors using phthalocyanine pigments. It is remarkable. The present invention has been made in view of the above-mentioned actual state of the art. That is, an object of the present invention is to provide a drum unit that always obtains a good and uniform image at the start of use after transporting and storing the electrophotographic photosensitive member.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies and as a result, by incorporating a conductive powder and / or a conductive resin in a cleaning blade and a film seal in a drum unit, The inventors have found that the object is achieved and have completed the present invention. That is, the drum unit of the present invention is a drum unit having at least an electrophotographic photosensitive member and a cleaning blade and / or a film seal that is in contact with the photosensitive member, and the cleaning blade and / or the film seal is made of conductive powder and / or Alternatively, it is characterized by containing a conductive resin.

In the present invention, as the constituent material of the cleaning blade and the film seal, a rubber material and its foam, and foams of various synthetic resins are used. Specifically, natural rubber, isobrene rubber, butadiene rubber, Styrene / butadiene rubber, butyl rubber, ethylene / propylene rubber, ethylene vinyl acetate copolymer,
Examples thereof include chloroprene rubber, chlorosulfonated polyethylene, chlorinated polyethylene, epichlorohydrin rubber, nitrile rubber, nitrile / isoprene rubber, acrylic rubber, urethane rubber, polysulfide rubber, silicone rubber and fluororubber. As the conductive powder and the conductive resin contained in the cleaning blade and the film seal, known ones are used. Specifically, as the conductive powder, carbon powder, metal powder, metal oxide are used. Powder,
Examples of the organic metal compound powder and the like, and examples of the conductive resin include conductive polymers such as polyacetylene.

The volume resistance of the cleaning blade and the film seal is 10 ¹¹ Ωcm or less, preferably 10 ⁸
Ωcm or less is desirable. Volume resistance is 10 ¹¹ Ωc
If it exceeds m, static electricity is generated when friction occurs between the photoconductor and the cleaning blade and the film seal, and a memory is generated in the photoconductor due to the influence of charges injected from the surface of the photoconductor.

[0007]

According to the present invention, when the cleaning powder and / or the film seal of the drum unit contains the conductive powder and / or the conductive resin, the photosensitive member, the cleaning blade and the film seal are prevented from being affected by vibration or shock during transportation or movement. Even if friction occurs, the potential difference between the surface of the photoconductor and the cleaning blade and film seal
It is less likely to occur and it is possible to prevent the generation of static electricity. Therefore, the memory effect on the electrophotographic photosensitive member does not occur due to the stress of static electricity, image defects are prevented from occurring, and a good and uniform image can be obtained even after being moved and stored.

The memory effect on the electrophotographic photosensitive member due to the stress of static electricity is characteristic of the charge generating material of the electrophotographic photosensitive member, and is particularly remarkable in the organic photosensitive member using the phthalocyanine pigment. However, it is considered that the reason is the hole traps existing on the surface of the phthalocyanine pigment. On the surface of the phthalocyanine pigment, hole traps due to impurities and lattice defects exist, so the photocharges after light irradiation are trapped by the hole traps and interfere with the transport of photogenerated carriers until the traps are completely filled. Will end up. Therefore, it is known that the initial surface potential is less attenuated and the sensitivity is lowered. The memory on the photosensitive member due to static electricity is generated by injecting the generated static electricity into the photosensitive member, so that the hole traps possessed by the phthalocyanine pigment are prefilled and partially sensitized. Since this hole trap has a negative polarity, the trap is filled only when the static electricity injected into the photoconductor is positive charge. Therefore, when the static electricity injected into the photoconductor is a negative charge, this effect is not exerted, and the memory effect does not occur. In the case of a drum unit having a cleaning blade and / or a film seal containing conductive powder and / or a conductive resin, positive and negative charges are generated even if the surface of the photoconductor rubs against the cleaning blade and the film seal. Since it becomes difficult, it is possible to completely prevent the memory on the photoreceptor due to static electricity.

[0009]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic explanatory view of an embodiment of a drum unit of the present invention, in which 1 is a toner recovery box, 2 is a photoconductor, 3 is a cleaning blade, and 4 is a film seal. Hereinafter, the cleaning blade and the film seal forming the drum unit having the above structure will be shown together with specific examples and comparative examples. Here, "part"
Means "parts by weight".

Example 1 Polyester (manufactured by Dainippon Ink and Chemicals, Inc.) 100 parts Isocyanate 20 parts Carbon powder 20 parts After dehydrating polyester at 120 ° C. for 30 minutes under reduced pressure,
20 parts of the above carbon powder is added and stirred. Next, isocyanate was added and poured into a mold of 15 mm × 280 mm × 2 mm and cured at 100 ° C. for 3 hours to prepare a cleaning blade. In addition, it is 10 mm × 2 by the same manufacturing method.
An 80 mm film seal was made. The volume resistance of these cleaning blade and film seal was measured and found to be 10 ⁸ Ω · cm.

Comparative Example 1 A cleaning blade and a film seal of Comparative Example 1 were prepared in the same manner as in Example 1 except that the carbon powder was not added. The volume resistance was 10 ¹⁴ Ω · cm. The cleaning blade and the film seal of Example 1 and Comparative Example 1 thus produced were placed in a cleaning unit of a printer (XP-11 manufactured by Fuji Xerox Co., Ltd.) to produce a drum unit. The electrophotographic photosensitive member used here was an organic photosensitive member in which a charge generating layer and a charge transporting layer were laminated on a 40 mmφ aluminum pipe. An x-type metal-free phthalocyanine was used as the charge generation material, and polycarbonate Z was used as the resin of the charge transport layer. This drum unit was packed in the conventional form. Load this packing box on a truck for transportation and
After being transported at a distance of 00 Km, it was stored in a chamber at 28 ° C. and 85% RH for 30 days. Then, the printer (XP-11, manufactured by Fuji Xerox Co., Ltd.) was mounted, and halftone images were collected and evaluated. The results are shown in Table 1.

[0012]

[Table 1]

Examples 2, 3, 4 A cleaning blade and a film seal were prepared in the same manner as in Example 1 except that the addition amount of carbon powder in Example 1 was changed to 5 parts, 10 parts and 15 parts, respectively. These are Examples 2, 3, and 4, respectively. The volume resistance of the blade and seal used here was 10 ¹² Ω · c, respectively.
m was 10 ¹¹ Ω · cm and 10 ⁹ Ω · cm. The cleaning blade and the film seal were installed in the same cleaning unit as above to prepare a drum unit. I packed this drum unit. After loading this packing box in a truck for transportation and carrying about 1000 km,
It was stored in a chamber at 28 ° C. and 85% RH for 30 days.
After that, the printer was mounted on a printer (XP-11, manufactured by Fuji Xerox Co., Ltd.), and halftone images were collected and evaluated. The results are shown in Table 2.

[0014]

[Table 2]

Example 5 Polyester (manufactured by Dainippon Ink and Chemicals) 100 parts Isocyanate 20 parts Polyacetylene 50 parts Polyester was dehydrated under reduced pressure at 120 ° C. for 30 minutes,
Add isocyanate. Furthermore, while stirring, polyacetylene was added and poured into a mold of 15 mm × 280 mm × 2 mm and cured at 100 ° C. for 3 hours to prepare a cleaning blade. Similarly, 10 mm x 280 mm
The film seal of was produced. When the volume resistance of these cleaning blade and film seal was measured, it was 10 ⁸ Ω · cm. The cleaning blade and the film seal were set in the cleaning unit in the same manner as in Example 1 to produce a drum unit. The drum unit was transported and stored in the same manner as in Example 1 and then evaluated in the same manner. The results are shown in Table 3.

[0016]

[Table 3] As is clear from the results of Tables 1 to 3, by lowering the volume resistance of the cleaning blade and the film seal in contact with the photoconductor, a good and uniform image can be obtained at the start of use after transportation and storage. ..

[0017]

Since the present invention has the above-mentioned structure, it is possible to prevent static electricity caused by friction between the photosensitive member and the cleaning blade or the film seal due to vibration, impact, etc. during transportation, movement and storage. Therefore, when the drum unit of the present invention is used, the electrophotographic photosensitive member after transportation, movement, and storage does not cause a memory effect due to the stress of static electricity, and therefore, an image defect is generated in the obtained copy image. And the image quality is good and uniform.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of a drum unit of the present invention.

[Explanation of symbols]

1 ... Toner collection box, 2 ... Electrophotographic photoreceptor, 3 ... Cleaning blade, 4 ... Film seal.

Claims (2)

[Claims] 1. A drum unit including at least an electrophotographic photosensitive member and a cleaning unit having a cleaning blade and / or a film seal which is in contact with the photosensitive member, wherein the cleaning blade and / or the film seal is made of conductive powder and / or Alternatively, a drum unit containing a conductive resin. 2. The drum unit according to claim 1, wherein the cleaning blade and the film seal have a volume resistance of 10 ¹¹ Ω · cm or less.