| 摘要 |
PURPOSE:To easily eliminate the density irregularity of an image by detecting the impedance of a conductive toner, which exists between a toner drum and a non- magnetic sleeve, so that the toner supply of a hopper is controlled. CONSTITUTION:If a toner 9 is made to take a tower condition in the clearance 5 between a sleeve 4 and a toner drum 2 by the actions of magnets 3 and 6, a detecting head 11 arranged above the clearance 5 is brought into contact with the toner tower. In both the detected impedance at the time when the most proper quantity of the toner for forming a tower is expreimentally determined and the rotating speed of the roller of the toner supply unit at that time are used as standards, the head 11 fails to contact with the toner in case the toner bomes short. As a result, the impedance is changed, and a detecting circuit S feeds through a control circuit R the signals for increasing the rotating speed of drive means of a toner supplying unit 8. When the toner takes the most proper tower condition to detect the standard impedance, the toner supply roller is decelerated to restore the standard condition. Thus, it is possible to simply eliminate the density irregularity of the image. |
