| 摘要 |
PROBLEM TO BE SOLVED: To modulate D/A at high speed and to realize the high speed modulation of a semiconductor laser by controlling so that the light quantity of the semiconductor laser may be maximum one for forming an electrostatic latent image by adding a minimum light quantity control signal set to minimum one by which the electrostatic latent image is not formed and an output signal from the D/A. SOLUTION: Relating to an electrophotographic device that a laser beam is emitted from the semiconductor laser 40 and the optically scanning laser beam is radiated to a photoreceptor so as to form the electrostatic latent image, in a laser beam modulation circuit 45, a D/A converter 20 converts light quantity data into an analog signal. A photodiode 11 detects the light quantity of the laser 40. A minimum light quantity setting circuit 43 controls the light quantity of the laser 40 according to a signal from the photodiode 11 so that it may not form the electrostatic latent image on the photoreceptor. A maximum light quantity setting circuit 44 controls so that the maximum light quantity for forming the electrostatic latent image may be obtained by adding the minimum light quantity control signal set to be the minimum light quantity and the output signal from the converter 20. |
