The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 08, 1997
Filed:
May. 31, 1994
Ricoh Company, Ltd., Tokyo, JP;
Abstract
In the roller charging apparatus according to the present invention, the charging roller includes a layer of an epichlorohydrin rubber, so that it is possible to eliminate electric nonuniformity of a conductive elastic layer and to be charged by loading only a DC voltage. The charging roller also may have a surface layer formed of polyamide resin or fluorine resin. In addition durability can be improved by setting the roller hardness of the charging roller to 42 (measured by a JISA hardness meter) or more. Further, a roller diameter D.sub.r of the charging roller and drum diameter D.sub.d of the photosensitive drum may satisfy the relation of D.sub.d /D.sub.r .gtoreq.4. A cleaner can also be provided for removing foreign materials, such as toner, from the charging roller, and the cleaner may have a rubber hardness less than that of the charging roller.