| 摘要 |
PROBLEM TO BE SOLVED: To safely control the rotation of the rack of a developing unit by simple constitution without deteriorating the efficiency of a space near the rack in a rotary type developing device driven by a motor. SOLUTION: This developing device is the full color developing device constituted so that the plural developing units 31 are fitted to the rack 80. The rack 80 can be rotated in a direction shown by an arrow (c) with a supporting shaft 81 as a supporting point. Then, the respective developing units 31 are intermittently rotated 90 deg. by 90 deg. and respective developing sleeves 32 are set at a developing position D faced to a photoreceptor drum 10. A lock lever 84 and a solenoid 86 driving the lever 86 are installed to be near to the rack 80. When the solenoid 86 is turned off, the pawl part 84a of the lever 84 is engaged with one of projections 83 so as to lock the rack 80. When the solenoid 86 is turned on, the engagement of the lever 86 with respect to the projection is released. At this time, a current value flowing to the solenoid 86 is monitored and timing that the solenoid 86 is perfectly turned on is detected. Based on the turning-on timing, the rotation driving motor 82 of the rack 80 is started. |
