| 摘要 |
PURPOSE:To eliminate misoperation and to improve operability by inhibiting a selection of a developing device unless at least one of plural detachable developing devices is attached. CONSTITUTION:The 1st and the 2nd developing devices 321 and 322 of a developing device 10 are provided to a main frame detachably. Developing device presence/absence signals from the 1st and the 2nd developing devices 321 and 322 are used after the power source is turned on to check whether a developing device is attached and detached or not and when not, a signal from a cover opening/closing detecting device 13 is used to check whether the developing device is attached securely or not. When the cover opening/closing detecting device 135 detects the closure of a hopper cover 131, it is decided that the developing device is attached. Then, a developer on the sleeve of the attached or detached developing device is removed and a stand-by state is entered. Thus, when both or either of the 1st and the 2nd developing devices is not attached, a selection of a developing device is inhibited, so there is no misoperation and the operativity is improved. |
