| 摘要 |
PURPOSE:To perform toner concentration detection of less malfunctions through the utilization of the fluidity of developer by comparing the flow-down of developer in the change of the rate of throttling of a throttle member with the developer flow- down in the reference rate of throttling indicating an adequate toner concentration. CONSTITUTION:A storage vessel 13 for storing nearly a constant volume of developer is provided in the lower part of the opening provided on the way of a scraping plate 8 in the developer circulating path and the throttle plate 14 provided in the lower part thereof is moved horizontally by an operating lever 15 to gradually reduce the rate of throttling from the maximum rate, at which time the condition of the developer flow-down is observed. A detecting lever 16 is disposed below the throttle plate 14 and measures the rate of throttling when there is no more flow down of the developer and a switch 17 went OFF. The difference between this and the reference rate of throttling is obtained, based on which the toner or carrier is replenished into the developer in the developer vessel 1 from a replenishing device 9, whereby the correct maintenance of the toner concentration is achieved. |
