Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Post imaging process – finishing – or perfecting composition...
Reexamination Certificate
2000-06-20
2001-03-20
Martin, Ronald (Department: 1753)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Post imaging process, finishing, or perfecting composition...
C399S350000
Reexamination Certificate
active
06203962
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an electrophotographic image forming method, an electrophotographic image forming apparatus, a processing cartridge and an electrophotographic photoreceptor, particularly relates to an electrophotographic image forming method and an electrophotographic image forming apparatus having a process for cleaning a toner remained on an organic photoreceptor by a brush roller and an elastic rubber blade while the photoreceptor is moving, and a processing cartridge and an electrophotographic photoreceptor to be used in the apparatus.
BACKGROUND OF THE INVENTION
Recently, an organic photoreceptor containing an organic photoconductive substance is most widely used for the electrophotographic photoreceptor. The organic photoreceptor has advantages such that the material responding to various exposure light sources from visible light to infrared light can be easily developed, a material without environmental pollution can be selected and the production cost is low, compared with another photoreceptor. However, only a drawback of the organic photoreceptor is weak in the mechanical strength and the surface of the photoreceptor is deteriorated or damaged for a lot of copying or printing.
Generally, in the electrophotographic copying apparatus according to Carlson method, a photoreceptor is uniformly charged and the charge is imagewise eliminated by light exposure to form a static latent image. The static latent image is visualized by developing by a toner, and the toner is transferred to paper and fixed.
However, the toner on the photoreceptor is not all transferred and a part of the toner is remained on the photoreceptor. When the image formation process is repeated under such the condition, a high quality copied image without any contamination cannot be obtained since the latent image formation is disturbed by the influence of the remained toner. Accordingly, it is necessary to remove the remained toner. A fur brush roller, a magnetic brush roller or a blade is usually used for the cleaning means, and the blade is mainly used from the viewpoint of the performance and the structure thereof. A plate of rubber elastic material is usually used for the material of the blade.
As above-mentioned, an electrical and mechanical force are directly applied to the surface of the photoreceptor by the charging means, the developing means, the transferring means and the cleaning means. Accordingly, a high resistivity to such the forces is required to the photoreceptor. Particularly, a high resistivity to the wear or scratch formation of the surface of the photoreceptor caused by the friction, and a high mechanical durability to peel of the layer caused by an impact by intruding a foreign substance or removing a jammed paper are required. Specifically, the durability to the damage and peel of the layer the same as that of an inorganic photoreceptor is strongly demanded.
Until now, various investigations have been performed to satisfy the requirements as above-mentioned.
It has been reported regarding the mechanical durability, that the wearing property of the surface and the toner filming resistivity can be improved by using a bisphenol Z type polycarbonate resin as the binder at the surface of the organic photoreceptor. Japanese Patent Publication Open to Public Inspection (JP O.P.I.) No. 6-118681 discloses the use of a colloidal silica-containing hardenable silicone resin as the surface of the photoreceptor.
However, the photoreceptor using the bisphenol Z type polycarbonate resin is insufficient in the resistivity to the wearing and not has the sufficient durability. Besides, the surface layer of the colloidal silica-containing hardenable silicone resin is superior in the strength and is widely studied for the means for raising the anti-wearing property and the anti-scratch property which are the drawback of the OPC. However, a problem of the electricity property under a low humidity is raised when the siloxane resin is used in the surface layer. Although it has been tried for improve such the problem to reduce the surface electric conductivity by an addition of an electroconductive particle, a problem of occurring an image flowing under a high temperature and a high humidity has been raised. The inventors has found that the electricity property under a condition low temperature and low humidity can be improved by combining a charge transportable structural unit into the siloxane resin (Japanese Patent Application No. 11-70380).
However, a problem that the blade is apt to bend or warp accompanied with the raising the surface friction of the surface of photoreceptor and cleaning blade during the cleaning, as a result of incorporating the structure unit having transportable ability.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a stable and excellent electrophotographic image forming method, as well as an electrophotographic image forming apparatus, which minimizes the generation of excessive frictional force between an electrophotographic photoreceptor and an elastic body rubber blade, prevents the generation of blade curl, and is capable of effectively removing residual toner on said photoreceptor in an electrophotographic image forming method in which a residual toner on said electrophotographic photoreceptor is removed employing an elastic body rubber blade, and a processing cartridge employed in said electrophotographic image forming apparatus.
The present inventors have discovered that when an electrophotographic photoreceptor having structural units which exhibit charge transport performance as the photoreceptor and also having a resin layer, comprising a siloxane based resin having a crosslinked structure is employed, and the residual toner on said photoreceptor is removed employing a cleaning process comprising an elastic body rubber blade, the object of the present invention is achieved by controlling said elastic body rubber blade under specified conditions.
1. In an electrophotographic image forming method in which, after transferring a toner image on an electrophotographic photoreceptor onto a recording material, the residual toner on said photoreceptor is removed employing an elastic body rubber blade, an electrophotographic image forming method wherein said photoreceptor has structural units exhibiting charge transport performance; also has a resin layer comprising a siloxane based resin having a crosslinked structure; said rubber blade is brought into contact with said photoreceptor in the opposite direction; and the residual toner on said photoreceptor is removed by vibrating said rubber blade at an amplitude of 10 to 200 &mgr;m.
2. In an electrophotographic image forming method in which after transferring a toner image on an electrophotographic photoreceptor onto a recording material, the residual toner on said photoreceptor is removed employing an elastic body rubber blade, an electrophotographic image forming method wherein said photoreceptor has structural units exhibiting charge transport performance; also has a resin layer comprising a siloxane based resin having a crosslinked structure; polyurethane rubber is employed having a hardness at 25±5° C. between 65 and 80 in terms of JIS A Scale and an impact resilience at 25±0.2° C. between 20 and 75; said rubber blade is brought into contact with said photoreceptor in the opposite direction; and the residual toner on said photoreceptor thereby is removed.
3. The static friction coefficient of said elastic body rubber blade with respect to said photoreceptor is preferably no more than 1.0.
4. Said resin layer preferably comprises fine organic particles having an average particle diameter of 0.05 to
10 &mgr;m.
5. Said fine organic particles are preferably those comprising fluorine atoms.
6. Said resin layer preferably comprises antioxidants.
7. The resin layer of said photoreceptor is preferably comprised of a siloxane based resin which is obtained through reaction of an organic silicon compound having a hydroxyl group or a hydrolyzable group wi
Itami Akihiko
Kitahara Yohko
Kurachi Masahiko
Oshiba Takeo
Sakimura Tomoo
Bierman Jordan B.
Bierman, Muserlian and Lucas
Konica Corporation
Martin Ronald
LandOfFree
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