Patent ID: 8761624
Filing Date: 2014-06-24
Classification: G03G

Abstract:
1. An image forming device configured to form toner images on corresponding photosensitive bodies, and configured to perform primary transfers for transferring the toner images on the corresponding photosensitive bodies onto an intermediate transfer body and to perform a secondary transfer for transferring the toner images from the intermediate transfer body onto a recording medium; the image forming device comprising: a position correction unit configured to cause plural toner image forming units to form predetermined patterns and configured to correct forming positions of the toner images by the corresponding toner image forming units in a direction parallel to a rotation axis of the intermediate transfer body, based on information about spacing among the patterns, the spacing among the patterns being read by a pattern reading unit, a position detection unit configured to detect a position of the intermediate transfer body in the direction parallel to the rotation axis; a position control unit configured to control movement of the intermediate transfer body; a speed determination unit configured to determine whether a speed in the direction parallel to the rotation axis of the intermediate transfer body is stabilized, based on a time variation of the position of the intermediate transfer body detected by the position detection unit; and an image forming control unit configured to cause the position correction unit to correct the forming positions of the toner images, configured to cause the plural toner image forming units to form the corresponding toner images, configured to cause the image forming device to perform the corresponding primary transfers, and configured to cause the image forming device to perform the secondary transfer, wherein, when the position control unit controls the movement of the intermediate transfer body so that the intermediate transfer body is moved in the direction parallel to the rotation axis to a target position, the position control unit causes the intermediate transfer body to move to the target position at a constant speed at least during a part of a first time interval, the movement of the intermediate transfer body being controlled by the position control unit during the first time interval, and wherein, when the speed determination unit determines that the speed in the direction parallel to the rotation axis of the intermediate transfer body is stabilized, the image forming control unit causes the position correction unit to correct the forming positions of the toner images, and subsequently, the image forming control unit causes the plural toner image forming units to form the corresponding toner images, causes the image forming device to perform the corresponding primary transfers, or the image forming device to perform the secondary transfer, during a time interval in which the intermediate transfer body is moving in the direction parallel to the rotation axis of the intermediate transfer body at the constant speed.