| 摘要 |
PURPOSE: To prevent impact from occurring when a developing gear is meshed with a driving gear by arranging the respective rotation centers of the developing gear at a developing position, the driving gear and a developing unit on an identical straight line and controlling them so that the driving gear is rotated when the developing gear is meshed with the driving gear. CONSTITUTION: The developing gears 14, 14R and 14B driving respective developing rollers are freely rotatably arranged around the rotation center 0 of the developing unit 1. Besides, the driving gear 111 selectively meshed with the developing gear by the rotation of the unit 1 is supported at a part other than the unit 1 so that the position is fixed. Then, the respective rotation centers 0', 0" and 0 of the gear 14 at the developing position, the gear 111 and the unit 1 are arranged on the almost identical straight line and controlled so that the respective developing gears are revolved and the gear 111 is rotated when they are meshed with the gear 111. Besides, the rotation center 0" of the gear 111 is positioned between the rotation centers 0' and 0 of the gear 14 at the developing position and the unit 1 in order to enhance the maintainability of the device. |
