Optical scanner

An optical scanner comprising:

• a light source device for emitting a light beam for performing an optical scanning operation;
• a cylindrical lens system for converging the light beam from the light source device only in a cross scan-corresponding direction and focusing and forming the light beam as a linear image extending in a main scan-corresponding direction;
• an optical deflector for reflecting the light beam from this cylindrical lens system on a deflecting reflecting face and deflecting this light beam at an equal angular velocity;
• an image forming mirror system having an anamorphic single concave mirror for converging the deflected light beam as a light spot on a scanned face and performing the optical scanning operation at an equal speed by using said light spot, said anamorphic single concave mirror being formed by an aspherical surface;
• and
• an adjusting mechanism means for fixing said cylindrical lens system after displacing and adjusting a position of said cylindrical lens system in an optical axis direction thereof so as to correct an error of a diameter of said light spot in said cross scan-corresponding direction based on errors in manufacture and assembly of the image forming mirror system only when said cylindrical lens system is mounted and assembled.