| 摘要 |
PROBLEM TO BE SOLVED: To provide a dustproof structure of an optical box capable of preventing dust from entering the optical box. SOLUTION: After a laser beam is deflected by a polygon mirror 46 in an optical box 11, the laser beam goes out from the optical box 11 through an opening 84 passing through an optical system and arrives at a photographic paper. When dust is stuck to the polygon mirror 46 or optical system, the performance is lowered so that a dustproof property is required for the optical box 11. As a result, a fan 102 is provided and a blow is supplied to the inner section of the optical box 11 to pressurize the inner section so that it is possible to prevent the dust from entering the optical box 11 from the outside thereof, thereby preventing the dust from being stuck to the polygon mirror 46 and optical system. |
