Abstract: According to an aspect of the present invention, there is provided a scanning optical system, which is provided with a light source that emits a plurality of beams, a deflector that simultaneously deflects the plurality of beams incident thereon, and an imaging optical system having a scanning lens and compensation lenses. Each of the compensation lenses has a lens surface whose optical surface reference axis is tilted with respect to an optical surface reference axis of the scanning lens. At least one of lens surfaces of each of the compensation lenses is formed to be an aspherical surface defined by a two-dimensional polynomial expression.

Abstract: In a scanning optical system including a polygon mirror for dynamically deflecting N laser beams corresponding to N color components and an imaging optical system for converging the laser beams into spot beams on N photosensitive drums respectively, the imaging optical system includes: a front lens group for converging the laser beams principally in a main scanning direction while deflecting the beams to deviate from its optical surface reference axis; and N rear lens groups for converging the laser beams principally in an auxiliary scanning direction respectively. The rear surface of the front lens group and front surfaces of the rear lens groups are formed as two-dimensional polynomial aspherical surfaces. Concretely, the rear surface is formed as a step-like optical surface having N discrete areas of different heights.

Abstract: In a scanning optical system, a plurality of laser beams pass through an imaging optical system and converge on surfaces to be scanned, respectively. The imaging optical system includes a scanning lens and a plurality of long lenses for the respective beams. The scanning lens has an anamorphic aspherical surface, and each long lens has at least one two-dimensional polynomial aspherical surface.

Abstract: There is provided a scanning optical system, which is provided with a light source that emits at least one beam, a polygonal mirror, and an imaging optical system that converges the at least one beam deflected by the polygonal mirror to form at least one beam spot on a surface to be scanned. The at least one beam incident on the polygonal mirror is inclined in an auxiliary scanning direction which is perpendicular to the main scanning direction. Further, at least one lens surface of the imaging optical system is configured such that a beam reflected therefrom proceeds toward an outside region of the polygonal mirror.

Abstract: There is provided a scanning optical system which includes a light source, a line-like image forming optical system, a polygonal mirror, and an imaging optical system. The line-like image forming optical system forms a line-like image extending in the main scanning direction in the vicinity of a reflective surface of the polygonal mirror, and if the number of reflective surfaces of the polygonal mirror is less than or equal to six and if |m|>1.

Abstract: According to an aspect of the present invention, there is provided a scanning optical system, which is provided with a light source that emits a plurality of beams, a deflector that simultaneously deflects the plurality of beams incident thereon, and an imaging optical system having a scanning lens and compensation lenses. Each of the compensation lenses has a lens surface whose optical surface reference axis is tilted with respect to an optical surface reference axis of the scanning lens. At least one of lens surfaces of each of the compensation lenses is formed to be an aspherical surface defined by a two-dimensional polynomial expression.

Abstract: A scanning optical system is provided with a light source that emits at least one beam, an anamorphic optical element that converges the at least one beam in an auxiliary scanning direction, a polygonal mirror, and an imaging optical system. The imaging optical system has a scanning lens, and a compensation lens. One surface of the scanning lens has an anamorphic aspherical surface whose curvature in the auxiliary scanning direction is determined independently from a cross-sectional shape thereof along the main scanning direction. Further, one surface of the compensation lens has an aspherical surface in which a tilt angle of a cross-sectional shape in the auxiliary scanning direction changes with a position in the main scanning direction, the aspherical surface being asymmetrical with respect to a plane perpendicular to the auxiliary scanning direction and including a central point thereof.

Abstract: In a scanning optical system including a polygon mirror for dynamically deflecting N laser beams corresponding to N color components and an imaging optical system for converging the laser beams into spot beams on N photosensitive drums respectively, the imaging optical system includes: a front lens group for converging the laser beams principally in a main scanning direction while deflecting the beams to deviate from its optical surface reference axis; and N rear lens groups for converging the laser beams principally in an auxiliary scanning direction respectively. The rear surface of the front lens group and front surfaces of the rear lens groups are formed as two-dimensional polynomial aspherical surfaces. Concretely, the rear surface is formed as a step-like optical surface having N discrete areas of different heights.

Abstract: A laser beam emitted by a light source is incident on one of reflecting surfaces of a polygon mirror. The laser beam reflected by the reflecting surface is dynamically deflected in a main scanning direction due to the revolution of the polygon mirror and enters a scanning lens.

Abstract: A scanning optical system deflects a light beam by a reflection surface of a polygon mirror toward an object surface through an image forming optical system so that the light beam scans on the object surface to form an image thereon. A light shielding member is disposed between the polygon mirror and the image forming optical system. The shielding member is an opaque plate disposed perpendicular to the optical axis of the image forming optical system. The light shielding member prevents a ghost light that is reflected by another reflection surface of the polygon mirror located adjacent to the reflection surface deflecting the light beam from entering the image forming optical system and impinging onto the object surface.

Abstract: A projection optical system, which is telecentric with respect to an object side and an image side, projects a pattern onto an image plane, which is substantially parallel with the pattern, at a substantial equi-magnification. The projecting optical system is provided with first and second condenser lenses having a common (first) optical axis which is perpendicular to the pattern and the image plane. The projection optical system further includes an imaging lens having a second optical axis that intersects with the first optical axis at an intermediate position between the first and second condenser lenses. A first mirror reflects a beam from the pattern and passed through the first condenser lens toward the imaging lens. A second mirror reflects the beam passed through the imaging lens to the imaging lens, and a third mirror reflects the beam passed through the imaging lens toward the second condenser lens.

Abstract: A scanning optical system is provided with alight source that emits at least one beam, an anamorphic optical element that converges the at least one beam in an auxiliary scanning direction, a polygonal mirror, and an imaging optical system. The imaging optical system has a scanning lens, and a compensation lens. One surface of the scanning lens has an anamorphic aspherical surface whose curvature in the auxiliary scanning direction is determined independently from a cross-sectional shape thereof along the main scanning direction. Further, one surface of the compensation lens has an aspherical surface in which a tilt angle of a cross-sectional shape in the auxiliary scanning direction changes with a position in the main scanning direction, the aspherical surface being asymmetrical with respect to a plane perpendicular to the auxiliary scanning direction and including a central point thereof.

Abstract: A scanning optical system is provided with a light source, a polygonal mirror, and an imaging optical system that converges the at least one beam deflected by the polygonal mirror. The imaging optical system has a scanning lens, and a compensation lens. The light source is arranged so that beams emitted by the light source are incident on the polygonal mirror from the outside of the predetermined scanning range in the main scanning direction and are incident on the polygonal mirror being inclined in an auxiliary scanning direction with respect to a plane perpendicular to a rotational axis of the polygonal mirror. Further, at least one surface of the scanning lens has a first anamorphic surface, power of the first anamorphic surface in the auxiliary scanning direction is distributed asymmetrically in the main scanning direction with respect to an optical axis of said scanning lens.

Abstract: A scanning optical system includes a light source that emits a plurality of beams, a polygonal mirror that deflects the plurality of beams emitted by the light source to scan within a predetermined angular range, and an imaging optical system that converges the plurality of beams on a plurality of surfaces to be scanned, respectively. The imaging optical system includes a scanning lens and a plurality of compensation lenses located between the scanning lens and a plurality of surfaces to be scanned. The plurality of beams passed through the scanning lens are incident on the plurality of compensation lenses, respectively. Each of the plurality of compensation lenses having an anamorphic surface, shapes of which in a main scanning direction are substantially the same with respect to each other.