| 摘要 |
PROBLEM TO BE SOLVED: To restrain vibration and to improve image quality by miniaturizing an optical box. SOLUTION: If the optical box 10 incorporating a rotary polygon mirror 3 and an image-forming lens 4 is large in size, the box 10 is largely vibrated in the midst of the rotation of the mirror 3 and the image quality is deteriorated, A BD sensor 6 for detecting a scanning start signal is disposed on the outside of the box 10 and fixed on a stay 20 supporting the box 10. By making the box 10 small in size and have high rigidity, the vibration is restrained and the improvement of the image quality and the reduction of cost are accelerated. |
