Patent ID: 7197255
Filing Date: 2007-03-27
Classification: G03G

Abstract:
1. An image forming apparatus that carries out image formation by primarily transferring images electrophotographically formed on an image carrier onto a rotatably driven intermediate transfer member, and then secondarily transferring the images on the intermediate transfer member onto a recording medium, comprising: a cleaning device that cleans a surface of the intermediate transfer member; a contacting/separating device that contacts/separates said cleaning device with/from the intermediate transfer member; a detecting device that detects a circumferential length of the intermediate transfer member in a circumferentially moving direction thereof; a controller that controls image formation timing for the image carrier based on the circumferential length detected in timing when said contacting/separating device contacts/separates said cleaning device with/from the intermediate transfer member, and the circumferential length detected in timing when said contacting/separating device does not contact/separate said cleaning device with/from the intermediate transfer member, wherein said controller comprises: a signal generating device that generates an image formation start signal for a plurality of respective colors; a target value setting device that sets a target value of the image formation timing to be input to said signal generating device based on the circumferential length detected by said detecting device in timing when said contacting/separating device does not contact/separate said cleaning device with/from the intermediate transfer member; and a correcting device that corrects the target value set by said target value setting device, based on the circumferential length detected by said detecting device in timing when said contacting/separating device contacts/separates said cleaning device with/from the intermediate transfer member, and wherein said signal generating device comprises at least two signal generating devices that generates respective signals for recording mediums at odd and even number-th positions attached to the intermediate transfer member, and said target value setting device sets target values of image formation timing for the respective signals for recording mediums at odd and even number-th positions attached to the intermediate transfer member.