| 摘要 |
PURPOSE:To obtain images of good quality by measuring the dielectric loss tangent between electrodes, where a developer is interposed, to detect the toner concentration and keeping the toner concentration of the developer constant. CONSTITUTION:A developer 3 of a developing device 1 is supplied to a photosensitive drum 2 in accordance with rotation of a developing roll 4, and a part of this developer is supplied between counter electrodes 9 by a guide member 8 and an electrostatic capacity Cx and a resistance Rx of the developer 3 between electrodes 9 are detected by an LCR meter 10. If the detected value exceeds a set value 11, a motor 13 is rotated to drive a toner replenishing roll 5a and a toner 6 stored in a hopper 5 is supplied into the developing device 1. When the toner concentration reaches the prescribed value 11, a comparing means 12 stops driving of the motor 13; and this operation is repeated to keep the toner concentration constant in the developing device 1. Thus, the developing device 1 always develops images with a good quality. |
