Yasuyuki Shibayama

Laser printer optics with use of slant scanning of multiple beams

Simultaneous scanning of multiple beams in an array is an effective method to realize high-speed and high-resolution printers. The arrayed multiple beams can be generated by devices such as grating, Wollaston prism, fiber array, and laser diode array. In any of these devices, the focused spots in an array have a period several tens of times larger than the spot diameter. We propose a simultaneous scanning method suitable for these devices in which the arrayed multiple beams are arranged in a slant angle to the scanning direction to produce consecutive scan lines. Laser print experiments with two or four beams were carried out, and high-performance printing of a 431.8-mm print width, 23.6 dot/mm (i.e., 600 dot/in.) resolution, and of 541-mm/s speed were realized.

Optics for modulating multiple beams using an asymmetric multilevel phase grating and a multichannel acousto-optic modulator.

Asymmetric multilevel phase gratings for generating even numbered beams have been designed, assuming that their phase patterns are formed by overlapping plural binary-phase patterns, each of which has an arbitrary phase height. The grating for four beams, which produces uniform and high intense diffraction orders of the minus first to the plus second order, is fabricated. The efficiency is 75.5%, although the theoretical efficiency is 79.9%. It is also demonstrated that the optics in which the beams from the grating are fed into a multichannel acousto-optic modulator through a Fourier-transform lens makes their successful modulation possible for pulse signals of 20-ns pulse duration.