Patent ID: 6664996
Filing Date: 2003-12-16
Classification: B41J,G02B,H04N

Abstract:
A laser beam scanner comprising:at least a set of laser light sources for emitting a laser light beams, a laser driver provided with a laser light intensity sensor and adapted for driving at least one laser light source to emit a laser light beam within a first predetermined variation range under a feedback control using said laser light intensity sensor, a modulator for modulating an intensity of the laser light beam passing therethrough, a modulator driver for driving said modulator by using a set of optical modulation data for the laser light beam, and a modulated beam sensor disposed on an optical path of the laser light beam downstream of said modulator for sensing the intensity of the laser light beam that has passed through said modulator and has been modulated by said modulator; said modulator driver including: a renewable first memory for memorizing the set of optical modulation data corresponding to respective stages of gradation of image data for the laser light beam; a second memory for memorizing a set of standard intensity values corresponding to a plurality of predetermined stages of the gradation of the image data for the laser light beam; a difference calculator for calculating difference values between actual intensities of the laser light beam sensed by said modulated beam sensor and the standard intensity values stored in said second memory; and a compensator for compensating the optical modulation data in accordance with the difference values calculated by said difference calculator to maintain the intensity of the laser light beam having passed through said modulator within a second predetermined variation range less than the first predetermined variation range at each stage of gradation.