Electrophotography – Internal machine environment – Particle or contaminant control
Reexamination Certificate
1998-11-10
2001-07-24
Lee, Susan S.Y. (Department: 2852)
Electrophotography
Internal machine environment
Particle or contaminant control
C399S103000
Reexamination Certificate
active
06266500
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to a developing apparatus and a process cartridge.
In an electrophotographic image forming apparatus using an electrophotographic image forming process, a process cartridge is used, which contains the electrophotographic photosensitive member and process means actable on said electrophotographic photosensitive member, and which is detachably mountable as a unit to a main assembly of the image forming apparatus (process cartridge type). With this process cartridge type, the maintenance of the apparatus can be carried out in effect by the user without depending on a serviceman. Therefore, such a process cartridge type is now widely used in electrophotographic image forming apparatuses.
In such a developing device in a process cartridge, there is provided a seal member for preventing leakage of the developer(toner) out of the developing zone, at each of the opposite ends of the rotatable developer carrying member(developing roller). Conventionally, such a seal member is a elastic member such as felt or rubber foam.
The developing roller contains a fixed magnet roller therein. It is rotatably supported on the developing container through bearings. Therefore, the toner supplied from the toner container is deposited on the surface of the developing roller by the magnetic force provided by the magnet roller. The developing blade regulates the layer thickness of the toner deposited on the peripheral surface of the developing roller. Thereafter, the toner is fed to the electrophotographic photosensitive drum with the rotation of the developing roller. It is deposited onto the latent image formed on photosensitive drum to develop the image. The developing roller is provided with an elastic sealing member at each of the opposite ends thereof. By press-contacting the elastic sealing member to the outer surface of the developing sleeve, the toner is prevented from leaking out.
On the other hand, it has been proposed a developing sleeve is provided with a seal member (magnetic sealing member) of magnetic material with a predetermined gap at each of the opposite ends thereof to prevent the toner from leaking out.
By using the magnetic seal member, the developing roller and the seal member can be out of contact from each other. Accordingly, the rotation torque of the developing roller can be remarkably reduced. Therefore, the driving motor may be downsized and may be less expensive. The variation of the rotation torque is small, and the developing roller and the photosensitive drum can be rotated a uniform speed. Therefore, the deterioration of the image quality attributable to any rotation nonuniformity can be prevented. Also, the wearing can be avoided.
The present invention is directed to a further improvement of such a process cartridge.
SUMMARY OF THE INVENTION
Accordingly, it is a principal object of the present invention to provide a developing device and a process cartridge wherein the leakage of the developer can be prevented.
It is another object of the present invention to provide a developing device and a process cartridge wherein a developer having passed through a gap between a developer carrying member and a magnetic seal member are prevented from reentering the gap.
It is a further object of the present invention to provide a developing device and a process cartridge having a developer regulating member contacted to a peripheral surface of the developer carrying member to prevent the developer having passed through a gap between a developer carrying member and a magnetic seal member from reentering the gap.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.
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Patent Abstracts of Japan, vol. 1998, No. 02, Jan. 30, 1998 (English Abstract of—JP 09-258560).
Karakama Toshiyuki
Numagami Atsushi
Oguma Toru
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Lee Susan S.Y.
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