Electrophotography – Having particular structure – Modular or displaceable
Reexamination Certificate
1996-02-28
2001-06-19
Grainger, Quana M. (Department: 2852)
Electrophotography
Having particular structure
Modular or displaceable
Reexamination Certificate
active
06249661
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a copier, laser printer, facsimile apparatus or similar electrophotographic image forming apparatus and, more particularly, to a device for supporting an image carrier included in such an apparatus and implemented as a photoconductive drum.
It has been customary with an image forming apparatus of the type described to rotatably mount an image carrier, e.g., a photoconductive drum on a shaft which is affixed to the side walls of the apparatus body. To replace the drum, the shaft is unlocked and then removed from the apparatus body and drum so as to release the drum. Subsequently, the drum is removed from the apparatus body. The drum may be constructed into a unit together with a section for storing fresh toner and a section for collecting used toner or waste toner, as known in the art. This kind of unit is also removed from the apparatus body by pulling out a shaft supporting the drum and then removing the entire unit from the apparatus body. In any case, the drum is replaced after the shaft supporting it has been pulled out. However, pulling out the shaft from the apparatus body and drum with one hand while holding the drum with the other hand is not only time- and labor-consuming but also needs a great deal of skill. Moreover, despite that a new drum to be mounted to the apparatus body should have the photoconductive surface thereof kept off the operator's hands, the portion of the drum which can be directly touched is limted. In this way, the operation for mounting and dismounting a photoconductive drum available with the conventional apparatus is troublesome.
Further, in the unit configuration mentioned above, the shaft of the drum is supported by the apparatus body while a developing roller is supported by the unit. This brings about a problem that the distance between the drum and the developing roller is fixed. When the drum and developing roller fail to contact each other evenly in the axial direction or are not parallel to each other due to, e.g., irregularities in their outside diameters, the resulting images suffer from irregularities.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a supporting device which allows a photoconductive drum to be replaced rapidly and easily.
In accordance with the present invention, an image forming apparatus has a photoconductive drum, and a device for supporting the drum. The device has a shaft supporting the drum at the axis of the drum, a pair of flanges respectively affixed to opposite ends of the drum, and each being formed with a bearing hole at the center thereof, the shaft extending throughout the bearing hole to allow the flange to slide thereon, a pair of locking members formed at opposite ends of the shaft, and each comprising flat surfaces facing each other and formed by cutting away part of the periphery of the end of the shaft in parallel planes at opposite sides of the axis, and round surfaces facing each other and formed by the other part of the periphery, a pair of shaft support members for respectively holding the locking members, and each comprising an opening for passing the flat surfaces of the respective locking member therethrough, and a circular hole communicated to the opening for engaging with the round surfaces of the respective locking member, and a pair of knob members respectively provided on the opposite ends of the shaft.
Also, in accordance with the present invention, an image forming apparatus has a photoconductive drum, and a device for supporting the drum. The device has a pair of flanges respectively affixed to opposite ends of the drum, a conductive shaft press fitted in a through bore formed in the center of one of the flanges, while partly protruding from the through bore, a shaft support member rotatably supporting the conductive shaft, a first positioning member for positioning the drum by holding the shaft support member, a flange support member rotatably supporting the other flange, and a second positioning member for positioning the drum by holding the flange support member.
Further, in accordance with the present invention, a device for supporting an image carrier included in an image forming apparatus has a pair of flanges respectively mounted on opposite ends of the image carrier, and having respective through bores formed therein. A shaft extends throughout the through bores of the pair of flanges. A pair of locking members are respectively formed at opposite ends of the shaft, and each has flat portions facing each other and curved portions facing each other and formed by having the circumferential surface thereof cut away in parallel planes at opposite sides of the axis of the shaft. The locking members each has an oval shape in a section perpendicular to the axis of the shaft. A pair of shaft support members each includes a circular hole having an inside diameter capable of receiving the arcuate portions of one of the locking members, and an opening communicated to the circular hole and for passing the flat portions of the locking member therethrough. The locking members are respectively received in the circular holes of the shaft support members to thereby lock the shaft in position.
Furthermore, in accordance with the present invention, a device for supporting an image carrier included in an image forming apparatus has a pair of flanges respectively mounted on opposite ends of the image carrier, and having respective through bores formed therein. A shaft extends throughout the through bores of the flanges. A pair of notched portions are respectively formed at opposite ends of the shaft, and each has flat portions facing each other and curved portions facing each other and formed by having the circumferential surface thereof cut away in parallel planes at opposite sides of the axis of the shaft. The locking members each has an oval shape in a section perpendicular to the axis of the shaft. A pair of shaft support members each includes a circular hole having an inside diameter capable of receiving the arcuate portions of one of the notched portions, and an opening communicated to the circular hole and for passing the flat portions of the notched portion. A pair of affixing members respectively affix the pair of shaft support members. The notched portions are respectively affixed to the affixing members via the associated shaft support members.
Moreover, in accordance with the present invention, a device for supporting an image carrier included in an image forming apparatus and implemented as a photoconductive drum has a shaft supporting the drum at the axis of the drum, a pair of flanges respectively affixed to opposite ends of the drum, and each being formed with a bearing hole at the center thereof, the shaft extending throughout the bearing hole to allow the flange to slide thereon, a pair of locking members formed at opposite ends of the shaft, and each comprising flat surfaces facing each other and formed by cutting away part of the periphery of the end of the shaft in parallel planes at opposite sides of the axis, and round surfaces facing each other and formed by the other part of the periphery, a pair of shaft support members for respectively holding the locking members, and each comprising an opening for passing the flat surfaces of the respective locking member therethrough, and a circular hole communicated to the opening for engaging with the round surfaces of the respective locking member, and a pair of knob members respectively provided on the opposite ends of the shaft.
In addition, in accordance with the present invention, a device for supportin an image carrier included in an image forming apparatus and implemented as a photoconductive drum has a pair of flanges respectively affixed to opposite ends of the drum, a conductive shaft press fitted in a through bore formed in the center of one of the flanges, while partly protruding from the through bore, a shaft support member rotatably supporting the conductive shaft, a first positioning member for positioning the dru
Hosokawa Hiroshi
Saitoh Hiroshi
Grainger Quana M.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Ricoh & Company, Ltd.
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