| 摘要 |
PROBLEM TO BE SOLVED: To accelerate heat radiation on the inside and the outside of an optical box by a cover which has good thermal conductivity. SOLUTION: A rotating polygon mirror 3 and an image-forming lens system 4 are incorporated in the optical box 10, and an aperture at the upper part of the optical box 10 is covered with a cover 20. The construction material of the cover 20 is material satisfactory in thermal conductivity, and the heat radiation on the inside and the outside of the optical box 10 is accelerated by covering the upper parts of a laser drive base plate 1c on the outside of the optical box 10 and a drive control board 11 which is the control part for the motor of the mirror 3 with the cover 20. |
