| 摘要 |
PURPOSE:To reduce a cost of a device and to elevate its whole accuracy, by driving a rotation of a rotary polyhedric mirror in a noncontact state, by a rotating magnetic field of a magnet which has been separated from said mirror by a prescribed space. CONSTITUTION:A ringlike magnet 15 is installed to the upper end of a mounting member 14 of a rotary shaft 12. On the upper part of this magnet 15, a rotary polyhedric mirror 16 is placed so as to be opposed, by separating it from the magnet by a prescribed space (d). On the lower end part of a supporting member 17, a hooking state part for hooking the rotary polyhedric mirror 16 is formed, the rotary polyhedric mirror 16, a timing encoder 18 and packing 19 are fitted into said part in a state that they have been piled up in order, and are clamped and fixed by a ringlike clamping member 20. On the upper part of the projecting part of the timing encoder 18, a light source 23 is provided, and on its lower part, a solar cell 24 is provided at a position opposing to the light source 23 through the timing encoder 18. |
