| 摘要 |
PURPOSE:To draw scanning lines for different colors by arranging an ultrasonic wave polarizer for separating a laser beam to two different directions at a prescribed period between an ultrasonic light modulator and a rotary polygon mirror. CONSTITUTION:The ultrasonic wave polarizer 30 and an optical angle amplifier 31 for expanding the separation angle of the beams separated by the polarizer 30 are arranged between a collimator lens 16 and a beam expander 17. The ultrasonic wave polarizer 30 is delayed at its response speed slower than of the ultrasonic light modulator 13 and a Bragg-diffracted laser beam is irradiated on a photosensitive drum 21. The timing of the Bragg's diffraction by the ultrasonic wave polarizer 30 is set so as to be generated for every scanning line 22 on the photosensitive drum 1. |
