A light beam scanning system in which deviations perpendicular to the scanning direction of the scan line due to parallelism deviations of a rotary multi-surfaced mirror are eliminated. A first linear image pattern is formed on the reflecting surface of the mirror parallel to the scanning direction by...http://www.google.fr/patents/US4281889?utm_source=gb-gplus-shareBrevet US4281889 - Light beam scanning system
