| 摘要 |
PURPOSE:To improve the image quality by eliminting scanning strains in a laser printer wherein a hologram is used by a method wherein not only the strength of the photo output of a semiconductor laser but also the wavelength of the photo output are controlled constant. CONSTITUTION:The monitor output of a semiconductor laser 1 is branched into two by a half mirror 12, one laser beam is inputted to a photo diode 2 wich composes a photodetector, thus photocurrent is converted into voltage by an amplifier 3 and compared with the reference voltage Vr1 in an error amplifier 4. The drive current of a dive circuit 5 is controlled by the output signal of the error amplifier 4, and accordingly the strength of the photo output of the laser 1 is controlled constant. The other laser beam banched by the half mirror 12 passes through a filter 13 and becomes incident to a photo diode 14 which composes a photodetetor, and then the photocurrent thereof is converted into voltage by an amplifier 15 and compared with the reference voltage Vr3 in an error amplifier 16, and accordingly the error thereof is amplified. A drive circuit 18 has the drive current for a Peltier element 17 controlled by the output signal of the error amplifier 16, while the temperature of the laser 1 is controlled by the Peltier element 17, and therefore the oscillation wavelength is controlled constant. |
