Patent ID: 9261841
Filing Date: 2016-02-16
CPC Classification: G03G

Claim Text:
1. An image forming apparatus which forms a color image by transferring images of respective colors formed on photosensitive members to an intermediate transfer member, the apparatus comprising: an image forming portion that forms a decision mark for deciding whether or not a color registration correction for correcting color shifts in the color image carries out, the decision mark being obtained by registering the respective color marks on the intermediate transfer member such that when color shifts do not occur the respective color marks are each formed at a same position on the intermediate transfer member; a detection portion that detects a width of the decision mark formed on the intermediate transfer member by the image forming portion; and a control portion that is configured to decide whether or not the color registration correction carries out based on the width of the decision mark detected by the detection portion; wherein the image forming portion forms plural decision marks on the intermediate transfer member and the control portion controls the image forming portion to change the frequency of forming the decision marks based on a variation amount in the widths of respective decision marks.