Patent ID: 7352978
Filing Date: 2008-04-01
Classification: G03G

Abstract:
1. A method of detecting a phase difference of a plurality of image bearing members of an image forming apparatus, the plurality of image bearing members including a reference image bearing member and corresponding image bearing members, the method comprising: transferring a reference toner mark carried by the reference image bearing member onto an image transferring member; transferring a reference image pattern carried by the reference image bearing member onto the image transferring member by at least one circumferential length thereof perpendicular to a moving direction of the image transferring member; transferring a corresponding image pattern carried by each corresponding image bearing member onto the image transferring member by at least one circumferential length thereof perpendicular to the moving direction of the image transferring member; detecting the reference image pattern and the corresponding image pattern by a plurality of detectors; calculating a sum of an elapsed time difference of the corresponding image pattern with respect to the reference image pattern; changing a phase of each corresponding image bearing member with respect to the reference image bearing member; repeating the above-described steps at least once; and storing a positional relation of the reference image bearing member and each corresponding image bearing member for which the sum of the elapsed time difference of the corresponding image pattern with respect to the reference image pattern is minimum.