| 摘要 |
PURPOSE:To eliminate the rotation irregularity of a polygon mirror and to prevent the polygon mirror from being contaminated with scattered lubricating oil by allowing the turning force of a motor to operate directly on a hub and rotating the mirror and hub together. CONSTITUTION:An L-sectioned cylindrical hub 2 fixed horizontally at right angles to the outer circumference of a rotatable vertical shaft 3 is provided to the outer circumference. Then, a polygon mirror 1 fixed thereto, an upper rotor plate 10 fixed to the outer circumference of the shaft 3 in parallel to the hub 2, and an upper magnet 7 provided to an upper rotor plate 9 fixed to a hub projecting arm are given a gap. A coil group 5 is attached to a stator coil substrate 6 provided to a lower case 15 at right angles to the shaft opposite to the magnet with the gap between. A lower magnet 7 is provided to the plate 10 opposite to the group 5 with the gap between and lubricating oil flow preventing devices are arranged on and under the shaft 3. Then, a member attached to the shaft 3 and the shaft 3 are allowed to rotate freely in the cavity consisting of an upper case 14 and a lower case bracket 16. |
