| 摘要 |
<P>PROBLEM TO BE SOLVED: To perform proper driving control over an endless moving member such as an intermediate transfer belt even if a discontinuous part outside a predetermined range is present among a plurality of marks succeeding at specified intervals in the endless movement direction of the endless moving member. <P>SOLUTION: A mark sensor 90 detects the plurality of marks which succeed on the intermediate transfer belt in the endless movement direction and a PLL controller 82 uses its output to control the speed or position of the belt. Here, if the discontinuous part is present among the marks, the speed control or position control becomes unstable. Therefore, a discontinuous mark detecting circuit 83 detects the discontinuous part from the output of the mark sensor 90 and when the discontinuous part is detected, the control by the PLL controller is turned OFF. Consequently, the PLL controller 82 is deterred from becoming unstable owing to the discontinuous part. <P>COPYRIGHT: (C)2004,JPO |
