Patent ID: 7869111

Claim:
An optical scanner that can scan a light flux from a light source to a photosensitive surface of each of a plurality of photoconductors in a main-scanning direction, comprising: a rotational deflector that reflects and deflects an incident light flux by a plurality of reflecting surfaces arranged corresponding to the plurality of photoconductors in a rotational direction to scan the incident light flux in the main-scanning direction, the rotational deflector in which an inclination angle of the plurality of reflecting surfaces with respect to a rotational axis of the rotational deflector is set to an angle depending on the photoconductor to which each of the reflecting surfaces corresponds; a pre-deflection optical system that shapes the light from the light source into a light flux having a predetermined cross-sectional shape and introduces the light flux to the rotational deflector, and also converges the light flux in a sub-scanning direction in the vicinity of the reflecting surfaces of the rotational deflector; and a post-deflection optical system that introduces the light flux reflected and deflected by each of the plurality of reflecting surfaces in the rotational deflector to the photosensitive surface of the photoconductor corresponding to each of the reflecting surfaces, the post-deflection optical system includes a common (commonly-used) optical element that applies power to the light flux reflected and deflected by the rotational deflector and introduced to each of the plurality of photoconductors, so as to make the light flux introduced to the photosensitive surface by the post-deflection optical system to have a predetermined optical characteristic on the photosensitive surface depending on an incident position of the light flux and a plurality of optical elements that are arranged on an optical path between the common (commonly-used) optical element and each of the plurality of photoconductors corresponding to each of the photoconductors, each of the plurality of optical elements having a positive power in a sub-scanning direction set depending on the corresponding photoconductors.