| 摘要 |
PROBLEM TO BE SOLVED: To eliminate a problem of occurrence of an increase in torque when rotation control parts at two position, which are driven by one and the same drive source, are started at the substantially same time. SOLUTION: In a direction from a start of half revolution to an end of the half revolution, a resisting force in a direction opposite to the rotational direction acts upon a DB disengaging cam 34 while a resisting force in the rotational direction acts upon ICL disengaging cam 20 so as to cancel out an increase in torque caused by the drive of two spring clutches. Further, when an intermediate image transfer belt makes contact with a photosensitive drum, the increase in torque due to the drive of the spring clutches passes over its peaks, before the end of the half rotation of the spring clutches, and at a position where the torque is lowered to a predetermined value, the intermediate image transfer belt starts making contact with a secondary image transfer roller. Thereby it is possible to disperse the torque peak in a short time. |
