DRIVING DEVICE FOR ROTARY POLYGON MIRROR

摘要

PURPOSE: To provide a rotary polygon mirror driving device used in an LBP (laser beam printer) where excellent rotational accuracy is realized, whose life is prolonged and which is thinned at low cost by eliminating the deterioration in rotational accuracy and the life of a bearing caused by heat generation. CONSTITUTION: This device is provided with a rotor 11 which is provided with a rotation axis 1 and a rotor magnet 4 and where a rotary polygon mirror 10 is fixed, and a stator 12 constituted of a stator coil 9 opposed to the rotor magnet 4 and generating electromagnetic torque and an iron stator base plate 6 where the bearing 7 journaling the rotation axis 1 is fixed. Then, the external shape of the base plate 6 is projected to the outside from the circumscribed circle of the polygon mirror 10 and the bearing 7 is fixed on the base plate 6 directly or through a member excellent in heat conductivity.