| 摘要 |
PROBLEM TO BE SOLVED: To arrange the image writing position by detecting a BID signal with a specific laser before detecting a BID signal with another semiconductor laser in next scanning line and calculating the difference between respective BID signals and then writing an image with another semiconductor laser while delaying a time difference from the BID signal. SOLUTION: A first laser emits light when the r.p.m. of a scanner motor 11 reaches a specified level and a counter 105d in an engine controller 105 counts the time T2 between a horizontal sync signal (DB signal) detected by a light receiving element 8 and the BD signal of a second laser to measuring the time. A CPU 105a in the engine controller 105 calculates the detection time differenceΔT2 between first and second lasers and the time differenceΔT1.2 when same laser emitted light continuously (where, Tl is the time when same laser emitted light continuously). The calculation results are stored in the RAM 105b in the engine controller 105.
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