| 摘要 |
PURPOSE:To prevent malfunction owing to uneven existence of the toner by outputting a detection signal when an end signal inputs continuously more than twice in a toner end detector for a copying machine which detects toner amount periodically. CONSTITUTION:When a pulse Sp is generated from a mechanism 10 which detects the residual amount of toner, the fall pulse by a differentiating circuit R1-C1 turns a transistor Tr1 on, thereby charging an integrating capacitor C2. Before the Tr1 goes OFF, a buffer amplifier 13 conducts to input an AND circuit 14. When the pulse Sp generates again before the amplifier 13 turns OFF upon discharging of the capacitor C2, a transistor Tr2 goes ON, and the another terminal of the AND circuit is inputted so that the toner end signal SE is inputted to a control circuit. The error of detection caused by the malfunction of mechanical parts owing to the uneven existence etc. of the toner is reduced. |
