| 摘要 |
PROBLEM TO BE SOLVED: To solve such the problem that hot air strikes the optical lens before being cooled when the distance between a polygonal mirror and an optical lens is short, and an air current flowing out of an opening for passing a laser beam is likely to stay and has difficulty in passing through the vicinity of the optical lens, since the distance between the optical lens and the opening is short, thus the thermal deformation of the optical lens becomes large and its influence upon image quality cannot be ignored. SOLUTION: A wall 27 provided between the polygon mirror 22 and the optical lens 24 has: an opening 28 through which a laser beam passes; and a second opening 29 through which the air on the polygon mirror side of the wall 27 passes to the optical lens side, and the air on the optical lens side passes to the polygon mirror side, with respect to the wall 27. COPYRIGHT: (C)2010,JPO&INPIT |
