| 摘要 |
PURPOSE:To make the remaining amt. of a developer detectable surely by detecting the change in electrostatic capacity owing to the remaining amt. of the toner between a pair of electrodes. CONSTITUTION:When a toner 3 exists sufficiently in a developing device 2, and a pair of electrodes 7a, 7b are in the toner 3, a monostable multi 9 does not output any signal. When the toner 3 decreases to expose the electrodes 7a, 7b, an output signal is obtained in the multi 9 and is applied via an LPF 10 to a comparator 11, by the compared output whereof it is detected that the amt. of the toner remaining in the developing device is small. |
