| 摘要 |
<P>PROBLEM TO BE SOLVED: To speedily detect a toner pattern formed on a transfer belt for every laser beam without need of any special mechanism. <P>SOLUTION: When a toner pattern detection part 111 detects a toner pattern formed with two laser beams by an imaging unit 131M, etc., a threshold value is used corresponding to a variation portion of light receiving amount by a light receiving part 2452 when the toner pattern is radiated by a light emitting part 2451 for the light receiving amount of the light receiving part 2452 when the transfer belt is radiated by the light emitting part 2451 of the detection sensor 245. In addition, when detecting the toner pattern formed by the imaging unit with one laser beam which is selected from the two laser beams, the threshold value corresponding to 1/n of the variation portion is used. <P>COPYRIGHT: (C)2008,JPO&INPIT |
