Electrophotography – Having particular structure – Modular or displaceable
Reexamination Certificate
1999-08-30
2001-07-24
Brase, Sandra (Department: 2852)
Electrophotography
Having particular structure
Modular or displaceable
Reexamination Certificate
active
06266503
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to a method for attaching an electrophotographic photosensitive drum to the frame of a process cartridge removably installable in the main assembly of an electrophotographic image forming apparatus, a method for replacing the aforementioned electrophotographic photosensitive drum, and a process cartridge.
The electrophotographic image forming apparatus referred to in this specification is such an apparatus that forms an image on a piece of a recording medium with the use of an electrophotographic image formation process. It comprises, for example, an electrophotographic copying machine, an electrophotographic printer (LED printer, laser beam printer, and the like), an electrophotographic facsimile machine, an electrophotographic word processor, and the like.
The process cartridge referred to in this specification is such a cartridge that integrally comprises at least one processing means among a charging means, a developing means, and a cleaning means, and an electrophotographic photosensitive member, and can be removably installed in the main assembly of an electrophotographic image forming apparatus.
A process cartridge system, according to which an electrophotographic photosensitive drum, and at least one processing means that works on the electrophotographic drum, are integrated into the form of a cartridge removably installable in the main assembly of an image forming apparatus, has been employed by an image forming apparatus, which employs an electrophotographic image formation process. A process cartridge system makes it possible for users to maintain the apparatus without relying upon service personnel, and therefore, it drastically improves the operational efficiency of the apparatus. Thus, a process cartridge has been employed in a wide range of image forming apparatuses.
A process cartridge is a cartridge that comprises an electrophotographic photosensitive drum and at least one processing means. As for the processing means, there are a charging means for charging an electrophotographic photosensitive drum, a developing means for developing an electrostatic latent image formed on an electrophotographic photosensitive drum, with the use of toner, a cleaning means for removing the toner that remains on the peripheral surface of the electrophotographic photosensitive drum, and the like.
In the past, in order to attach a photosensitive drum to the frame of the aforementioned process cartridge, each of the longitudinal ends of the photosensitive drum was provided with a drum shaft, and this structural arrangement has been well known. According to this structural arrangement, the process cartridge frame is provided with two holes: one for supporting the drum shaft at one of the longitudinal ends of the photosensitive drum, and the other for supporting the drum shaft at the other longitudinal end. Further, a portion of each of the frame portions provided with the hole for supporting the drum shaft was removed for fitting the drum shaft into the hole.
There has been known another structure, according to which only one of the longitudinal ends of a photosensitive drum is provided with the drum shaft; the other end is not provided with the drum shaft. More specifically, in order to support the drum, the drum shaft provided at one end of the photosensitive drum is inserted into the hole provided in one of the drum supporting portions of the cartridge frame, and another drum shaft is inserted into the other end of the photosensitive drum, from outside the frame, through the hole cut in the other drum supporting portion of the frame, after the other end of the photosensitive drum is moved to be aligned with the hole cut in the other drum supporting portion.
SUMMARY OF THE INVENTION
The present invention has been derived from the improvement of the aforementioned conventional technology.
Thus, the primary object of the present invention is to provide a method for attaching a photosensitive drum, a method for replacing a photosensitive drum, and a process cartridge, which improve the efficiency with which an electrophotographic photosensitive drum is attached to the frame of a process cartridge, and the efficiency with which an electrophotographic photosensitive drum is replaced.
Another object of the present invention is to provide a method for attaching a photosensitive drum, a method for replacing a photosensitive drum, and a process cartridge, which make it possible to reliably maintain the rotational accuracy of an electrophotographic photosensitive drum.
Another object of the present invention is to provide a method for attaching a photosensitive drum, a method for replacing a photosensitive drum, and a process cartridge, which are capable of minimizing the reduction in the process-cartridge frame strength.
Another object of the present invention is to provide a method for attaching a photosensitive drum, a method for replacing a photosensitive drum, and a process cartridge, which make it possible to provide a sufficient gap between the surface of the frame hole and the external peripheral surface of the drum shaft prior to the fitting of a bearing into the bearing hole of the frame. This aspect of the present invention improves the efficiency with which one of the longitudinal ends of a photosensitive drum is moved to a point, at which this longitudinal end of the drum becomes aligned with the projecting portion of the frame, after the drum shaft with which the other longitudinal end of the photosensitive drum is provided, is inserted into the corresponding shaft hole in the frame.
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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Kojima Hisayoshi
Mori Tomonori
Murayama Kazunari
Brase Sandra
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
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