| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an optical sensor for detecting the number of sheets that remains in a paper feeding tray.SOLUTION: When the number of remaining sheets is large, a pressurizing plate 23 is positioned on the side lower than an optical path L2 so that the optical path L2 is shielded with a sheet that is placed, and when the number of remaining sheets is small, the pressurizing plate 23 is positioned on the side upper than the optical path L2, to allow photodetection with a light receiving part 31B. When the number of remaining sheets comes to be zero, a movable member 29 penetrates a through hole 23A of the pressuring plate 23, to shield the optical path L2. Thus, only with a single optical sensor 31, a state where the number of sheets remaining in a paper feeding tray 17 is small and a state where the number of remaining sheets comes to be zero are detected.</p> |
