| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To detect with high accuracy an error of an output signal of a light sensor caused by a large amount of paper powder sticking to the light sensor. <P>SOLUTION: A document reader 1 includes a carrying path 104, the light sensor 132, a contact sensor 131 and a control device 150. Both of the contact sensor 131 and the light sensor 132 output low signals indicating that a document exists in a determining position or high signals indicating that no document exists in the determining position 130. The control device 150 determines that a signal outputted from the light sensor 132 is an error when the light sensor 132 outputs the low signal while the contact sensor 131 outputs the high signal. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
