PURPOSE: To express a high-quality image by a method wherein an input binary image signal or an input multivalued image signal is arithmetically processed, on the basis of the arithmetic result each switching means is selectively switched, and a smoothing or a half tone processing is conducted by laser beams of a plurality of light quantities.
CONSTITUTION: An electric current i1 is passed through a semiconductor laser 5 to emit it with a small light quantity. An electric current i1+i2 is passed through the semiconductor laser 5 to emit it with a standard light quantity. On the basis of a first image signal VIDEO1, a first switching circuit SW1 switches whether or not an electric current i1 is passed through the semiconductor laser 5. On the basis of a second image signal VIDE02, a second switching circuit SW2 switches whether or not an electric current i2 is passed through the semiconductor laser 5. A first constant current circuit CC1 determines an electric current i1 on a first laser light quantity control signal APCI which is an analog signal from a laser light quantity control CPU. A second constant current circuit CC2 determines an electric current i2 on a second laser light quantity control signal APC2 as an analog signal.
SAITO TETSUO
KASHIWABARA ATSUSHI
MANO HIROSHI
SETO KAORU
