| 摘要 |
PURPOSE:To improve the reliability by oscillating an oscillator in high-order mode in the beginning and then in basic mode when the amount of waste toner is close to a detection level. CONSTITUTION:A contact S is broken firstly to connect only a resistance Rf, and the oscillator of a piezoelectric sensor 40 is driven by its self-oscillating circuit on condition that the oscillator oscillates in high-order mode. Consequently, unnecessary toner which almost sticks on the oscillator is rejected and the oscillation state is held. When the amount of waste toner is close to the detection level at which a full-up state is actually entered, the contact S is made to put the oscillator of a piezoelectric sensor 40 in basic mode, thereby operating the oscillator in a high sensitivity state to a toner level. |
