| 摘要 |
PURPOSE:To decrease the number of parts, and to simplify assembly work and adjustment by forming a reflecting mirror for curving a scanning laser beam optical path, and a reflecting mirror for leading a scanning laser beam to a photodetector, as one parts. CONSTITUTION:As for a first mirror 10, a reflecting surface 11 for reflecting a scanning laser beam X' and curving an optical path is formed by performing the reflection coating to roughly the lower side half, and also, the upper side is formed as a transparent part 12 for passing the scanning laser beam X', and in a part of one side end of the transparent part 12, a scanning position detecting mirror part 11A being a reflecting surface is formed by performing the reflection coating. A second mirror 7 is installed in parallel to the scanning direction by allowing its reflecting surface 7A to be opposed to the reflecting surface 11 of the first mirror. A photodetector 6 is installed to the position opposed to the first mirror, where the laser beam is reflected by the reflecting surface 11 of the first mirror, reflected again by the second mirror, and also, reflected by the scanning position detecting mirror part 11A is made incident. In such a way, the assembly and the adjustment can be simplified.
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