| 摘要 |
PURPOSE:To prevent previously the useless transmission, by inhibiting the reception of the rolled recording paper of a facsimile device at the receiving side in case said recording paper remains by an amount equivalent just to a sheet of original. CONSTITUTION:The output of a phototransistor 5 serving as a photodetecting element is fed to comparators 7 and 8 respectively. The threshold voltage, i.e., the reference voltage level for operation of the comparator 7 is set at VREF1 that is intermediate voltage between Vp and Vm. While the threshold voltage of the comparator 8 is set at VREF2 that is intermediate between Vm and Ve. Therefore outputs 7a and 8a are not produced if the voltage Vp showing the presence of the recording paper is applied to the comparator 7. Then the comparator 7 delivers the output 7a showing that the recording paper equivalent just to a sheet of original is left when the voltage Vm showing that an end mark 6 is detected is applied. |
