| 摘要 |
PURPOSE: To provide a rotary polygonal mirror device having high scanning accuracy of a light beam with a structure which is excellent in the accuracy of unbalance quantity detection at the time of correcting dynamic balance and does not damage bearings, etc., during the correction operation. CONSTITUTION: A rotor 1 is composed of a revolving shaft 2, a permanent magnet 3 of an annular shape, a rotor yoke 4 in which the magnetic flux of the permanent magnet 3 passes and a polygonal mirror 5 which is fixed to this rotor yoke 4. The rotor 1 is held supported by the bearing 6 and a housing 7 projecting to hold this bearing. A disk-shaped rotating body 15 is mounted opposite to the polygonal mirror 5 at the lower part of the revolving shaft 2. A weight is added to a projection 12 formed in the upper part of the polygonal mirror 5 or the projection is cut off or the two-face balance correction to cut the part near the outer peripheral part of the disk-shaped rotating body 15 is executed at the time of executing the dynamic balance correction after assembly of this rotary polygonal mirror device. |
