| 摘要 |
PROBLEM TO BE SOLVED: To perform accurate signal determination without decreasing the number of signals which can be discriminated by a CPU even when the voltage value of a signal to be input to an AD port fluctuates.SOLUTION: A signal determination device 10 includes: an AD port 110 to which a plurality of recording paper size signals having different voltages are input; an A/D converter 101 for AD-converting the voltages of the recording paper size signals to be input to the AD port 110; a discrimination part 102 for discriminating the content of the recording paper size signals in accordance with which of a plurality of ranges do AD values obtained by AD-converting the voltages of the recording paper size signals by the A/D converter belong to; a mode setting part 103 for setting each operation mode in an image forming apparatus 1; a difference calculation part 104 for calculating a difference between the AD values obtained by AD-converting the voltages of the recording paper size signals in each operation mode state; and a threshold changing part 105 for changing a threshold defining each range to be used for signal discrimination by the discrimination part 102 in accordance with the calculated difference. |
