PURPOSE: To eliminate the overvoltage irregularity of a drive power source at the time of rising by detecting the rotating speed of a polygonal mirror motor by a rotation detector by using the output of a rotation detection sensor, and driving the polygonal mirror motor by a faster driving rotation clock than the rotating speed.
CONSTITUTION: A rotation detection sensor 2 is provided in a polygonal mirror motor 1, and the output of the rotation detection sensor 2 is output to a rotation detector 3. A rotation detection signal output from the rotation detector 3 is input to a rotating speed discriminator 4, a reference clock output from a controller 5 is compared with the rotation detection signal, and the result is output to the controller 5. If the rotating speed of the polygonal mirror motor 1 is faster than a reference clock, a drive clock for driving the polygonal mirror motor 1 is output from the controller 5 as a predetermined final driving rotation clock, input to a driving clock generator 6, the polygonal mirror motor 1 is driven through a driver motor 8 to be accelerated to a predetermined rotation.
IGARASHI AKIRA
MATSUDA TATSUO
MIKI HIDEAKI
