| 摘要 |
PROBLEM TO BE SOLVED: To obtain a scanning optical unit where the irregular pitch of an image or jitter are not caused by the vibration of a rotary deflector because an optical housing is not resonated even when the rotary deflector is rotated at plural kinds of rotating speed. SOLUTION: A light source assembly 1, a cylindrical lens part 2, the rotary deflector 3 and an optical element such as an fθlens 4, etc., are mounted on the optical system housing 10. The housing 10 is provided with five fitting holes 11 to 15 used when it is fixed in an image forming device main body at the corner parts of an outer peripheral part. All the five holes 11 to 15 are not simultaneously used to fix the housing in the image forming device main body. Namely, the optional fitting holes are selected and used to fix the housing 10 out of the five fitting holes 11 to 15 in order to remove the resonant frequency of the housing 10 from the vibration of frequency in accordance with the rotating speed of the deflector 3. |
