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:
May. 17, 1994
Filed:
May. 29, 1992
Shinji Imagawa, Yao, JP;
Koichi Inui, Higashiosaka, JP;
Sharp Kabushiki Kaisha, , JP;
Abstract
A contact charger includes a photoreceptor having a photosensitive layer formed on a surface of an electrically conductive drum base and a fixed coil connected to the drum base and ground. The contact charger charges the photosensitive layer by making a charge roller in contact with the photosensitive layer while being applied thereto DC voltage from a power supply. With this arrangement, in the case where a pin hole exists on the photosensitive layer, there may have a continuity between the charge roller and the drum base which may results in a sudden increase in current flowing between the drum base and ground. When this happens, however, since self-induced electromotive force, having a direction opposite to the electromotive force of the power supply, is generated by the fixed coil in response to a sudden increase in current, excessive current will not flow between the drum base and ground, thereby eliminating the possibility of a large drop in voltage of the power supply. As a result, the contact charger is always capable of appropriately charging the surface of the photosensitive layer even in the case where a defect such as a pin hole exists on the photosensitive layer.