Different laser printers have different printing functions, but their working principles are basically the same. They all go through seven processes: charging, exposure, development, transfer printing, power elimination, cleaning, and fixing, five of which are around the photoreceptor drum. When the text or image to be printed is input into the computer, it is preprocessed by computer software. Then, the printer driver is converted into a print command (printer language) that can be recognized by the printer and sent to the high-frequency drive circuit to control the opening and closing of the laser transmitter to form a dot matrix laser beam. Then, the sensitive drum in the electronic imaging system is axially scanned and exposed through the scanning rotating mirror. The longitudinal scanning is realized by the rotation of the sensitive drum itself.

The laser beam emitted by the laser is injected into the acousto-optic deflection modulator through the reflector. At the same time, the binary image text dot matrix information sent by the computer is sent to the font generator from the interface to form the binary pulse information of the desired font. The signal generated by the synchronizer controls 9 high-frequency oscillators, and then is added to the acousto-optic modulator through the frequency synthesizer and power amplifier to modulate the laser beam emitted by the reflector. The modulated light beam is shot into the multi-faceted rotating mirror, and then focused by the wide-angle focusing mirror and shot onto the surface of the photoconductive drum (selenium drum), so that the angular velocity scanning becomes the linear velocity scanning, and the whole scanning process is completed.