| 摘要 |
<p>PROBLEM TO BE SOLVED: To accurately detect the existence of a medium for a long period of time. SOLUTION: A medium detecting device is provided with a sensor output level storing means 33 for storing the output level (V0) of a transmissive type photosensor 10 read in the stage of no media, threshold value setting means 31 and 32 for setting threshold values (Vref-H, Vref-L) based on the output level (V0) stored in the sensor output level storing means 33 and the kind of a medium P, and a comparing and determining means 20 for comparing the output level (V0) from the transmissive type photosensor 10 with the set threshold values (Vref-H, Vref-L) and determining the existence of the medium P.</p> |
