Patent ID: 7937007
Filing Date: 2011-05-03
Classification: G03G

Abstract:
1. An image forming apparatus, comprising: a plurality of image bearing members, each of which is configured to bear a portion of a pattern image including a plurality of reference images in a given form and each portion of the pattern image being arranged on the surface of each respective image bearing member in a rotation direction of each image bearing member; an endless moving member disposed facing the plurality of image bearing members and configured to receive the pattern image from the plurality of image bearing members; an image detecting unit configured to detect the plurality of reference images in the pattern image transferred onto the endless moving member; a rotational angle detecting unit configured to separately detect each image bearing member when each image bearing member comes to a given rotational angle; and a controller configured to detect a speed deviation pattern per one revolution of each image bearing member based on a detection timing of each of the plurality of reference images by the image detecting unit and a detection result obtained by the rotational angle detecting unit, conduct a phase adjustment control for adjusting a phase of the speed deviation pattern of the plurality of image bearing members, and control formation of the reference images in the pattern image at a timing that the reference images of the pattern image are formed in a rotation direction of each image bearing member at a pitch thereof being obtained by dividing a circumferential length of each image bearing member by a non-integer number, wherein the controller is configured to detect the speed deviation pattern based on a result obtained from a phase component and a quadrature component of a frequency signal generated from the detection result obtained by the rotational angle detecting unit and a result of detecting the plurality of reference images in the pattern image transferred onto the endless moving member.