| 摘要 |
PURPOSE:To prevent damage of a copier member, by carrying on a process in the case of the disconnection of a temperature detector when the disconnection is detected during continuous copying operation, and preventing restart of the process after the completion. CONSTITUTION:Capacitor C21 is charged and exceeds a voltage set with resistance R21 and R22, at that time operation amplifier Q21 reaches level ''L'' in output, and transistor Q22 becomes nonconducting, accordingly, operation amplifier Q24, when thermistor TH21 is disconnected on supplying power, becomes level ''H'' in output, transistor Q25 becomes conducting, Q29 nonconducting, and interrupts power to heater H21. The output of amplifier Q24 for detecting the disconnection is transmitted to transistor Q25 after a timer consisting of resistance 23 and capacitor 21 has been up, thus permitting signal WAIT to be kept in level ''L'' by properly selecting the timer constant and copying restart after that to be hindered, consequently, damage of the copier member to be prevented. |
