| 摘要 |
PROBLEM TO BE SOLVED: To suppress the temperature rising of an image formation lens in a hermetically sealed optical box. SOLUTION: The hole 11a of the optical box 11 where a laser beam L from the image formation lens 16 passes is filled by a glass 17, and the upper aperture of the optical box 11 is covered with a cover 18. A partitioning plate 19 having a slit part 19a where the laser beam L passes is provided between a driving motor 15 and the image formation lens 16, and the inside of the optical box 11 is divided into a section A where the driving motor 15 is positioned and the section B where the image formation lens 16 is positioned. A heat-radiating member 20 is attached at the slit of the cover 18 on the upper side of the driving motor 15. The lower part 20a of the heat-radiating member 20 is arranged in the vicinity of the driving motor 15, and the upper part 20b of the heat- radiating member 20 is projected on the upper side of the cover 18, so that an interstice between the heat-radiating member 20 and the cover 18 is filled by a flange 21 provided at the outer periphery of the heat-radiating member 20. |
