| 摘要 |
PURPOSE:To prevent the excessive supply or the lack of a developer by carrying the developer from a second developer storage part to a first developer storage part at the time of detecting that the quantity of the developer is smaller than a set value in the stop state of a developer agitating member. CONSTITUTION:A toner sensor 13 as the developer detecting means is provided on an upper cover 1a of a developing device body 1 and when the toner concentration in a developing tank is reduced, this reduction is detected to rotate and drive a toner replenishing roll 15. A toner carrying screw 12 is rotated and operated together with a toner agitating member 14 to carry toner from the second toner storage part 9 to the first toner storage part 8 when it is detected by the sensor 13 that the quantity of toner is smaller than the set value on condition that the toner agitating member 14 is stopped. Since the quantity of toner is detected by the sensor 13 on condition that the toner agitating member 14 stops, erroneous detection does not occur and the first toner storage part 8 is prevented from being empty or toner is prevented from being excessively supplied to the first toner storage part 8. |
