The laser printer is composed of laser, acousto-optic modulator, high-frequency drive, scanner, synchronizer, optical deflector, etc. Its function is to modulate the binary dot matrix information sent by the interface circuit on the laser beam, and then scan it on the photoreceptor. The photosensitive body and the photographic mechanism constitute an electronic photographic transfer system, which transfers the image of pictures and texts on the photosensitive drum to the printing paper. The principle is the same as that of the copier. Laser printer is a non impact output device that combines laser scanning technology with electronic imaging technology.