| 摘要 |
PURPOSE:To detect quickly and easily abnormalities such as disconnection and short-circuit of a thermo-sensitive element with a simple constitution by converting the signal of the thermo-sensitive element of a fixing roller into multi-staged digital data so as to control the conduction to an exothermic body. CONSTITUTION:The thermo-sensitive element 26 detects the surface temperature of the fixing roller having a heater 25, and its signal is digitally converted by an A/D converter circuit 34 through a temperature detecting circuit 31 and inputted to a microcomputer 35 as the multi-ctaged temperature data. Then an SSR 36 is turned on-off, and the conduction of the heater 25 is controlled. The temperature at the time of short-circuit and disconnecting of the thermo- sensitive element 26 is stored in the microcomputer 35 as reference data. When the measured temperature at copying work is equal to the reference data, it is considered to be the abnormality of the thermo-sensitive element, and the conduction to the heater 25 is interrupted. Thus the abnormality can be detected quickly and easily with such simple constitution. |
