POLYGON MIRROR SCANNER DEVICE

摘要

PURPOSE:To stabilize the thrusting pressure and to improve the accuracy mainly against the deviation of the position of an optical scanning line and nonuniform density by pressing a polygon mirror by means of a ring-like member while decreasing the ratio of compressing load to the compressive displacement in the direction of rotating center of the polygon mirror. CONSTITUTION:A receiving base 32 having a cylindrical part is fixed on the rotary shaft of a motor 21. A polygon mirror 31 whose inner peripheral surface is engaged with the cylindrical part of the receiving base 32 is provided on the receiving base 32. A ring-like member 41a is engaged with the periphery of the protruded part from the cylindrical part of the receiving base 32. The ring-like member 41a having a recessed groove is a member for pressing the polygon mirror and made of aluminum. When the inner periphery of the member is put on the tip of the cylindrical part of the receiving base 32 and fixed by a screw 23, the ring-like member 41a is elastically deformed and the polygon mirror 31 is held vertically between the ring-like member 41a and the receiving base 32. Consequently, the variation of the thrusting pressure holding an individual polygon mirror is reduced.