Patent ID: 7395012

Claim:
An image forming apparatus comprising: a first photosensitive body and a second photosensitive body; a first driving unit which gives a driving force to said first photosensitive body and a second driving unit which gives a driving force to said second photosensitive body; a belt which is arranged between said first photosensitive body and said second photosensitive body; a first mark whose position changes when said first photosensitive body rotates and a second mark whose position changes when said second photosensitive body rotates; a first detecting unit which detects said first mark and a second detecting unit which detects said second mark; and a control unit which obtains a time difference between timing when said first mark passes through said first detecting unit and timing when said second mark passes through said second detecting unit, determines a time that is required until said second driving unit is stopped after the stop of said first driving unit, and set stop timing of said belt driving unit to timing between the stop of said first driving unit and the stop of said second driving unit.