| 摘要 |
PURPOSE:To surely confirm the toner replenishing operations to a developing device by discriminating whether or not the developing operations of the device are to be restored based on the toner concentration after a toner replenishing mechanism is driven for a prescribed period of time. CONSTITUTION:This developing device does not shift as in the conventional means to developing operations indiscriminately when its cover body 9 is closed, but shifts to the developing operations based on the state of the toner concentration detected by a concentration detection circuit 11 after a toner replenishing mechanism is driven for a prescribed period of time by means of a timer 17. Therefore, when a toner empty state occurs due to various irregular troubles taking place during the period until the cover body 9 is closed again after it is opened, the state is surely detected and execution of the developing operations with an insufficient quantity of toner after the cover body 9 is closed can be prevented surely. |
