| 摘要 |
PURPOSE:To facilitate adjustments when paper differ considerably in reflection factor and transmissivity is used by providing a decision means which compares the output of a holding means with outputs of plural photosensors and decide whether paper is present or not, and varying a reference signal. CONSTITUTION:The paper detecting device is equipped with the reflection type photosensors PS1-PSn, whose outputs are applied to minus input terminals of comparators CM1-CMn which decide whether respective sheets of paper are present or not. Output signals of the comparators CM1-CMn are inputted to a controller 1 through an input/output circuit 8. In this case, the reference signal is varied with a ten-key 2 to select a threshold level, so the kind of paper is changed, the photosensors PS1-PSn need not be adjusted. Therefore, adjustments when paper differing in reflection factor and transmissivity greatly is used are facilitated. |
