| 摘要 |
PROBLEM TO BE SOLVED: To correct variations in the output of a sensor and detect the kind of paper without increasing the package of the sensor by providing the D/A converting means and the like for setting threshold, based on the result of the A/D conversion of the signal from the sensor. SOLUTION: When a sensor 901 is lit by an ON signal, the reflected signal from a prism is outputted to an A/D circuit 902 and a comparator 905. Based on the signal from the A/D circuit 902, a CPU 903 sets the threshhold of the comparator 905 by using a D/A circuit 904. In the comparator 905, the identification and the detection of the kinds of paper are performed by comparing the analog signal from the sensor 901 and the threshhold value set by the D/A circuit 904. That is, the CPU 903 compares the digital signal converted through the A/D circuit 902 and the table, wherein recording-paper information is set beforehand, and identifies whether the recording paper is OHT and the second original drawing or the paper. Furthermore, in the setting of the recording-paper table, the setting conditions are changed as a matter of fact depending on the result of the investigation. |
