| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an image forming device capable of securely detecting whether a carried sheet is a plain paper or an OHP sheet by using one transmission-type sensor. <P>SOLUTION: Light radiated from a light emitting part 21a of the transmission-type sensor 21 passes through an opening window 20a provided on a sheet carrying path 20, then is reflected by a reflecting plate 22, then passes through the opening window 21a again, and then enters to a light receiving part 21b. An actuator switch 23 is supported rotatably in directions of arrows B, B' around a rotating shaft 23a. An optical path of the transmission-type sensor 21 is blocked in two ways which are first blocking caused by shielding of the opening window 21a by a sheet and second blocking caused by shielding by a shielding plate 24 due to the situation where the actuator switch 23 is fallen down in the arrow B direction by a sheet tip. Based on a difference between timing when the first blocking occurs and timing when the second blocking occurs, the transmission-type sensor 21 detects whether or not a sheet is transparent. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
