Patent ID: 7693468
Filing Date: 2010-04-06
Classification: G03G

Abstract:
1. An image forming apparatus, comprising: a plurality of image carriers to carry respective latent images; a plurality of drive sources to separately drive the plurality of image carriers; an optical writing unit to write the respective latent images on the plurality of image carriers; a plurality of developing units to separately develop the respective latent images written on the plurality of image carriers to form respective visible images; a transfer member, including a surface, to move, the transfer member including an intermediate transfer member and a recording medium; a transfer unit to transfer the respective visible images formed on the plurality of image carriers to the transfer member; an image sensor to sense a positional displacement detection pattern including the visible images on the transfer member to detect a positional displacement between the visible images on each of the plurality of image carriers, and to output a detection result of the positional displacement; and a control unit to execute a positional displacement correction control to calculate an amount of the positional displacement based on the detection result and to determine respective target drive speeds of the plurality of drive sources based on calculation results, the control unit being usable to control so that the positional displacement detection pattern is formed when the plurality of drive sources are driven at substantially identical speeds, the image sensor being usable to sense the positional displacement detection pattern thus formed, wherein when an error occurs in the execution of the positional displacement correction control, the control unit separately resets drive speeds of the plurality of the drive sources to speeds calculated in an immediately preceding execution of the positional displacement correction control.