| 摘要 |
PURPOSE:To detect correctly the residual quantity of a developer and prevent fog phenomena of images, by providing a detecting means, which changes the detection sensitivity for the residual quantity of the developer in accordance with a development processing quantity, and a detecting means which changes detectors for the residual quantity of the developer. CONSTITUTION:A developer T is stored in the storage aprt in the lower part of a main body vessel 3 of a developing device 2 and is agitated and circulated around a partition plate 6 by a return screw conveyor 4 and a feed screw conveyor 5. The device is so constituted that the residual quantity of the developer T in the storage part is detected as a change of magnetic permeability by a coil 10 which detects the accumulation quantity of the developer in a storage region formed with a feed screw roller 5, the partition plate 6, and the side wall of the developing device main body. On the basis of this detection, the developer is supplied newly from a supply inlet 11 if the developer is deficient. Thus, the residual quantity of the developer is detected correctly independently of the number of copies, and fog of images is prevented. |
