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:
Jul. 21, 2015
Filed:
Apr. 07, 2014
Canon Kabushiki Kaisha, Tokyo, JP;
Tetsuro Fukusaka, Abiko, JP;
CANON KABUSHIKI KAISHA, , JP;
Abstract
An image forming apparatus that reduces density irregularity caused by SD gap variation. A developing bias voltage for forming a developing electric field between a photosensitive drum and a developing sleeve is applied to the developing sleeve. Current values of an AC component of the developing bias voltage are detected while changing the acquisition timing for each rotation of the photosensitive drum, and detected current values are interpolated and averaged at each same phase with reference to the time of detection by the drum home position sensor HP. From the averaged current values of the variation curves of the developing bias AC current over the plurality of rotations, a correction table for an output control signal of the developing bias voltage is created. The developing bias voltage is controlled based on the created correction table.