| 摘要 |
PURPOSE:To cease an alarm signal and to evade misdetection by slipping a driving system when a load placed on a driving system for an electrode exceeds a prescribed value, and thus preventing the driving system from breaking and eliminating variation in impedance at the same time. CONSTITUTION:An agitation device 4 is equipped with wire-shaped agitating blades 10a and 10b on an agitating shaft 9 and when the rotary load on the shaft 9 exceeds the prescribed value, the blades 10a and 10b slip to prevent the shaft 9 from being overloaded. A developing sleeve 2, on the other hand, is applied with an AC voltage and the impedance between the blades 10a and 10b is measured to detect the amount of toner. When the toner residue decreases below a permissible value, the alarm signal is outputted, but said slip is caused, the impedance does not vary; when the variation quantity is 0, the output of the alarm signal is evaded to evade such misdetection that the alarm signal outputted although there is enough toner in a developing tank. |
