| 摘要 |
PURPOSE:To provide the rotary polygon mirror of simple constitution which rotates at a high speed over a wide range and is inexpensive. CONSTITUTION:The rotary polygon mirror device consists of a rotary body formed by fixing a polygon mirror 2 at one end of a cylindrical body 1, integrally forming a columnar body 3 in the center in the cylindrical body 1, add arranging a magnet 4 for a thrust bearing at its tip part, and an external case 11 which covers the outer peripheral surface of the cylindrical body 1 concentrically across a gap 14; and the gap 14 is used as a radial bearing and the cylindrical body 1 and external case 11 are made nearly equal in coefficient of thermal expansion. |
