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:
Sep. 18, 2001
Filed:
Jul. 21, 2000
Atsushi Inoue, Nara, JP;
Hiroshi Ishii, Osaka, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
A contact charging device includes a charging roller and a power source, the charging roller having a conductive core, a conductive elastic layer and a coating layer and rotating as being in contact with a photoreceptor drum made up of a conductive body and a photoconductor, and the power source applying between the core and the body a bias voltage in which an ac voltage has been superimposed on a dc voltage. The charging roller and the photoreceptor drum form an oscillation system of a characteristic frequency fm which oscillates due to static adsorptive force. The characteristic frequency fm is calculated from each parameter of the oscillation system, and a frequency fac of a superimposed ac voltage or twice the value of the frequency fac is set to fall within a range of fac≦0.5 fm or fac≧1.5 fm so as to suppress both resonance of the oscillation system and relatively large oscillation when taking viscosity damping resistance into consideration. A highly reliable contact charging device capable of surely preventing charging noise can be provided by adopting the highly universal condition of suppressing oscillation as obtained by an efficient method.