| 摘要 |
PROBLEM TO BE SOLVED: To accurately and easily adjust beam pitch. SOLUTION: This device is provided with a selector 24 switching beam power for adjusting beam pitch BP3 and beam power for printing BP1 and BP2, driving means 20 and 21 emitting beams, a cylindrical lens condensing the respective beams in a sub-scanning direction, an optical path correction means correcting the optical path of one beam, a beam splitter aligning the optical axes of the respective beams, a deflector deflecting the respective beams, a sensor part detecting the output levels of the respective beams, a knife edge installed in the optical paths of the respective beams between the beam splitter and the sensor part so as to shield the respective beams, a knife edge adjustment means moving the knife edge in the sub-scanning direction and an optical path correction driving means controlling the actions of the optical path correction means and the knife edge adjustment means based on the output of the sensor part. Then, the beam pitch is adjusted by the beam power BP3 selected by the selector 24.
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