Patent ID: 10634905

Abstract:
A distance between the rotary shaft and the pressurizing position of the polygon mirror by the mirror fixing spring is shorter than a distance between the rotary shaft and a position at which the polygon mirror comes into contact with the seat surface. When a difference between an outer radius and an inner radius of the polygon mirror is defined as A, and a difference between the distance between the rotary shaft and the pressurizing position of the polygon mirror by the mirror fixing spring and the distance between the rotary shaft and the position at which the polygon mirror comes into contact with the seat surface is defined as C, the relationship of 0<C≤A/4 is established. When a distance, in a direction orthogonal to the rotary shaft, between a position at which the inner diameter side of the polygon mirror comes into contact with the sleeve and the position of the seat surface is defined as E, the relationship of A/3≤E≤A/2 is established.