Patent Document ID: 20070140736
Application ID: 11635550
Patent Status: 0

Claim One:
1. An image forming apparatus, comprising: a plurality of image carriers to carry an image thereon; a plurality of drivers to drive each of the plurality of image carriers; a plurality of drive-force transmitting members to transmit a driving-force from the plurality of drivers to the plurality of image carriers; a developing unit, provided to each of the plurality of image carriers, to develop the image on each of the plurality of image carriers; a transfer member, being faced to the plurality of image carriers, to receive the developed image from each of the plurality of image carriers sequentially while endlessly moving in a given direction; an image detector to detect the developed image formed on the transfer member to check a detection timing of the developed image; a sensor, provided to each of the plurality of image carriers, to detect a rotational speed of each of the plurality of image carriers and to determine an rotational angle of each of the plurality of image carriers; and a controller to conduct an image-to-image displacement control, a speed-deviation checking, and a phase adjustment control, the image-to-image displacement control including an image forming of a detection image on the transfer member, the detection image including the developed image transferred from each of the plurality of image carriers, a detection of the developed image in the detection image with the image detector, and an adjustment of image forming timing on each of the plurality of image carriers, the speed-deviation checking including an image forming of a speed-deviation checking image on the transfer member transferred from each of the plurality of image carriers, the speed-deviation checking image including the developed image transferred from each of the plurality of image carriers, detecting the speed-deviation checking image with the image detector, determining a speed-deviation of each of the plurality of image carriers per one revolution based on a result detected by the image detector and a result detected by the sensor, and the phase adjustment control including a phase adjustment of each of the plurality of image carriers based on a result determined by the speed-deviation checking, and the controller sequentially conducts the phase adjustment control and the image-to-image displacement control before conducting an image forming operation on each of the plurality of image carriers.