| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To adjust the amount of light emission, in calculating a widthwise position of an endless belt on the basis of output signals output from a plurality of light receiving areas, without requiring precise positional control on the belt widthwise position. <P>SOLUTION: A main slit is configured to move across a light path of light from a light emitting part in the arrangement direction of two light receiving areas, along with widthwise displacement of an endless belt. In adjusting the amount of light emission so that the maximum value of the sum (Va+Vb) of two output signals Va and Vb output from the two light receiving areas becomes a prescribed maximum value, the control to adjust the amount of light emission is exerted by providing a sub-slit so that the output signals output within ranges D and E outside a range C where the sum shows the maximum value are constant, and by changing the amount of light emission so that the output signals attain a predetermined target value in the ranges D and E. <P>COPYRIGHT: (C)2013,JPO&INPIT</p> |
