| 摘要 |
PURPOSE: To obtain a developing device advantageous in the aspect of cost and space by providing a developing means, a detecting means for detecting toner concentration or toner end and a storage circuit. CONSTITUTION: A toner concentration sensor is constituted of a toner concentration detection part 19a detecting the toner concentration of developer in a developer container, and an oscillation control part 19c outputting a toner concentration detection signal in accordance with the mixing ratio(toner concentration) of the toner to carrier in the developer based on the detection signal from the detection part 19a from an output terminal 19b, and it is connected between a power source and ground GND. A control part controls a toner supply part based on the toner concentration detection signal from the output terminal 19b so as to keep the toner concentration of the developer constant. A parts detection part 22 consisting of a fuse 20 and a resistance, 21 and functioning as the storage circuit is added to the toner concentration sensor and the fuse 20 and the resistance 21 are connected between the power source and the ground GND in series. The resistance 21 stabilizes potential. |
