| 摘要 |
PROBLEM TO BE SOLVED: To enable a polygon mirror to achieve simultaneously the prevention of a change in a balance even in high speed rotation and high temperature running states without deteriorating the accuracy of a reflection surface at the time of fixing a rotary shaft and a mirror pressing member by screwing force in the case of screwing and fixing the shaft and the member in the state that a polygon mirror is held between a flange part (step difference) of the rotary shaft and the mirror pressing member. SOLUTION: In a polygon mirror fixing structure provided with a polygon mirror 101 engaging a center hole with a rotary shaft from the upper end part of the shaft and put on the upper surface of a flange provided on the rotary shaft, a mirror pressing member 102 for pressing the mirror 101 between the upper surface of the flange and the member 102 itself and plural fixing screws 103 for screwing and fixing the member 102 on the upper end surface of the rotary shaft, a press piece bringing the member 102 into contact with the upper surface of the mirror 101 is a ring shape, the diameter of an inner peripheral edge of the ring-shape press piece is made large than the inner diameter of the center hole of the mirror 101 and the respective screws 103 are respectively screwed to positions on respective lines connecting respective boundary parts between respective reflection surfaces with the center of the mirror 101. |
