| 摘要 |
PURPOSE:To replenish the toner stably by providing a replenishing permanent magnet roll in the toner hopper aside from a developing permanent magnet roll, detecting the toner volume on the non-magnetic sleeve and rotating the replenishing magnet roll through the utilization of the detection signal thereof. CONSTITUTION:A toner-replenishing permanent magnet roll 8 having a shaft 7 is rotatably provided above a developing permanent magnet roll 4 provided in the lower part of a large-size hopper 11 besides this roll. A cartridge type toner box 21 which is made large in size and removalbe is mounted to the hopper 11. A spring plate 23 is provided to the opening part 22 of the bottom part of the toner box 21 and is pushed up and opened by the member 11c of the drum side 11b when mounted to the hopper 11. When the volume of the toner stagnating on the surface of the developing sleeve 5 decreases, the member 10 moves to the position of the solid line. This moving state is detected witn, e.g., a microswitch or the like, whereby the toner-replenishing roll 8 is controlled of driving and the toner 2 replenished. |
