| 摘要 |
PURPOSE:To eliminate an over toner or the like to develop always an image with a normal developer denisty, by providing a position detecting means which detects the steady position of a developing device and controlling the toner supply independently of the detection signal of a density detecting means for a certain time after the operation of a copying machine. CONSTITUTION:A developing device 1 is provided with an agitating roll 8 of a developer 2 and a rotary developing roll 9. In a tank, an element 4, which detects a surface level 3 when a mixture ratio of the developer 2 is normal, is provided in a certain position. If this element 4 detects a level lower than the surface level 3, a toner 7 is supplied from a toner supply device 5. Then developer 2 is agitated by this supply; and when detected level is raised to detect the level 3, the toner supply is stopped. The device 1 is attachable and detachable. When the detecting means detects that the device 1 is pulled out, driving of a motor for supply of the device 5 is stopped independently of the detection state of the element 4. |
