| 摘要 |
PROBLEM TO BE SOLVED: To realize a compact and inexpensive image forming device capable of operating even in a state where weight distribution applied to a unit holding part is asymmetric with respect to the rotary shaft of the unit holding part. SOLUTION: The rotating speed of a rotary developing part 3 is varied in accordance with the attaching state of a developing unit to a supporting frame 3b. When the developing unit is not attached to the frame 3b (1) and when four developing units are all attached thereto, the developing part 3 is rotated at high rotating speed n1. Meanwhile, when the moment of inertia around the rotary shaft is biased, such as, when one (2 and 3) or three or two (5) developing units are attached, the developing part 3 is rotated at low rotating speed n3 or middle rotating speed n2, so that burden imposed on a driving motor is lightened. Therefore, a small-output motor can be used and the device is compactly and inexpensively constituted. |
