| 摘要 |
PROBLEM TO BE SOLVED: To precisely detect amounts of shifting in images of respective colors. SOLUTION: An image forming apparatus is provided with a shifting detection means for detecting the amount of shifting in images of respective colors formed on a medium by a plurality of image output means. In this case, the detection means is a reflection type optical sensor with a plurality of light emitting sections and a plurality of light receiving sections arranged in a main direction. The detection of the amount of shifting is carried out by a toner pattern formed on the medium by the plurality of image output means and the position of the toner pattern is calculated from detection results of respective reflected light beams of at least two or more irradiation spots that satisfy expression (1): F>(N-1)×L+D<SB>S</SB>among a plurality of irradiation spots emitted on the recording medium from a plurality of light emitting sections. Here, in the expression (1), F is width in the main direction of the toner pattern, N is the number of the plurality of irradiation spots used for detection of the position of the toner pattern, L is an interval in the main direction of a plurality of irradiation spots used for detection of the position of the toner pattern, and D<SB>S</SB>is a spot diameter in the main direction of the plurality of irradiation spots used for detection of position of the toner pattern. COPYRIGHT: (C)2011,JPO&INPIT |
