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:
Jun. 03, 2008
Filed:
Sep. 14, 2006
Junichi Noguchi, Suzhou, CN;
Junichi Noguchi, Suzhou, CN;
Canon Kabushiki Kaisha, , JP;
Abstract
To detect differences in the main-scanning length of each beam on a photosensitive member, patterns for correction are formed on the photosensitive member using only beams (L, LN) at both ends among a plurality of beams aligned in a sub-scanning direction. The patterns are transferred onto an intermediate transfer belt and detected with photosensors, a difference ΔLN of scanning length between a 1-st line and a N-th line is calculated, and a difference ΔLi of scanning length of a i-th line is calculated by ΔLi=ΔLN×(i/N−1) so as to proportionally distribute ΔLN to the i-th line. The scanning lengths of lines are respectively corrected to be equal each other using the obtained differences ΔLi of scanning length. Thus, an image forming apparatus and a control method that reduce a decline in image quality, even when scanning incident angles of laser beams onto a photosensitive member differ for each of beams on forming images by scanning a multiple lines with a multiple beams, can be provided.