| 摘要 |
PROBLEM TO BE SOLVED: To prevent the accuracy of a reflection face from being deteriorated by the distortion of a rotary polygon mirror. SOLUTION: A coupling part 20 is formed on the tip side of a rotary shaft 12 an engaging hole 22 is formed on the coupling part 20. Slittings 20A are formed on the coupling part 20, so that cantilever pieces 20B of three divided parts of the coupling part 20 are easily bent. A circular fixing hole 38 is formed on the rotary polygon mirror 32 having plural reflection faces 34 and an elastic sheet 42 is arranged along the innerwall face of the fixing hole 38. The coupling part 20 of the rotary shaft 12 is inserted into the hole 38 and the cantilever pieces 20B of the coupling part 20 are pressed into the inner wall face parts of the hole 38 corresponding to corner parts 36. A fixed force generating member 26 is inserted into the hole 22 and the contilever pieces 20B of the coupling part 20 are respectively extended. |
