Abstract: A scanning optical system condensing a beam deflected by an optical deflector so as to form a beam spot on a surface to be scanned, comprises two lenses. A lens on the side of optical deflector has a negative refracting power in sub-scanning direction. A lens on the side of surface to be scanned has a positive refracting power in the sub-scanning direction. At least one lens surface of the lens surfaces of the two lenses is such that a shape in a sub-scanning section thereof is a non-arc shape.

Abstract: A multi-beam scanning device is disclosed that is able to realize a stable and small beam spot and realize stable scanning line intervals between plural light beams. The multi-beam optical scanning device includes a first optical system which has a first lens for coupling the light beams from the light sources, and a second lens which is an anamorphic element having power at least in a sub scanning direction and for guiding the light beams from the first lens to the deflection unit; and a second optical system. At least the second lens includes a diffracting surface having power.

Abstract: A scanning optical system includes converges, with a single lens, a divergent luminous flux, which is deflected in a main scanning direction by an optical deflector, on a surface of a scan target. The lens has two surfaces in a biconvex shape in both the main scanning direction and a sub-scanning direction, and at least one of the surfaces is a toric surface in which a line that connects, on a cross section in the main scanning direction, centers of curvature in a cross section in the sub-scanning direction is nonlinear, and change of the curvature of the toric surface in the cross section in the sub-scanning direction along the main scanning direction is asymmetric with an optical axis of the lens. The surfaces are anamorphic surfaces.

Abstract: An optical element can effectively correct misalignment of focused positions of optical spots and an optical spot pitch deviation with respect to image heights due to a refractive index distribution therein. The optical element includes a lens, which serves as an optical system in an optical scanner, is shaped in such a profile that misalignment of a focused position of the optical spot due to the refractive index distribution is corrected for image heights.

Abstract: An optical element can effectively correct misalignment of focused positions of optical spots and an optical spot pitch deviation with respect to image heights due to a refractive index distribution therein. The optical element includes a lens, which serves as an optical system in an optical scanner, is shaped in such a profile that misalignment of a focused position of the optical spot due to the refractive index distribution is corrected for image heights.

Abstract: A scanning optical system condensing a light flux deflected by an optical deflector so as to form an optical spot on a surface to be scanned, includes a unitary lens, wherein: a lens configuration in a main scanning cross section is both surfaces with a convex configuration; a lens configuration in a sub-scanning cross section is both surfaces with a convex configuration; both surfaces of the lens are anamorphic surfaces; and a lateral magnification ?2 in a sub-scanning direction of a central image height of said optical system satisfies the following condition (1): 0.5?|?2|?3.0.

Abstract: An optical element can effectively correct misalignment of focused positions of optical spots and an optical spot pitch deviation with respect to image heights due to a refractive index distribution therein. The optical element includes a lens, which serves as an optical system in an optical scanner, is shaped in such a profile that misalignment of a focused position of the optical spot due to the refractive index distribution is corrected for image heights.

Abstract: A first optical system guides a light beam from a light source to an optical deflector, and a second optical system converges the light beam deflected by the optical deflector on a surface to be scanned. The first optical system includes at least one resin lens having a diffractive surface. The second optical system includes at least one resin optical element. A beam diameter depth in a main scanning direction, Wm, that can have a maximum intensity of 1/e2, satisfies conditions ?m1+?m2+?m3??d1×(f2/f1)2<Wm/40??(1) ?d1>0 and ?m2<0.

Abstract: A multi-beam optical scanning apparatus includes a semiconductor laser array slanted relative to a sub-scanning direction and emitting a plurality of optical beams; a coupling lens converting a shape of each optical beam emitted from the semiconductor laser array; and an aperture with an opening having a size of Am×As, arranged after the coupling lens in a direction in which the optical beam progresses, where Am is a dimension of the opening in a main scanning direction and As is a dimension of the opening in the sub-scanning direction. When a length in the main scanning direction of a contour line defined by 1/e2 strength of a maximum strength of an optical beam at the position of the aperture is Lm, and a length in the sub-scanning direction of the contour line defined by 1/e2 strength of the maximum strength of the optical beam at the position of the aperture is Ls, the following conditional expressions are satisfied: Am<Lm, and??(1) Ls/Lm×0.3<As/Am<Ls/Lm×1.7.

Abstract: An optical scanner which performs optical scanning of a surface to be scanned by deflecting a luminous flux having a wavelength ? from a light source by means of an optical deflector, and condensing the deflected flux toward the surface to be scanned through a scanning image forming optical system, thereby forming an optical spot on the surface to be scanned. The scanning image forming optical system has at least one lens, and when the focal length f? in the main scanning direction at a surface accuracy ?i is defined as follows: f?={2.

Abstract: An optical system includes three optical systems. The first has a coupling lens. The second includes a lens having a positive power in a vertical scanning direction and forms the light flux into a line image extending in the horizontal scanning direction on a deflector. The third includes a first lens having a positive power in the horizontal scanning direction, and a second lens having a positive power in the vertical scanning direction. Lateral magnification in the horizontal scanning direction is set larger than that in the vertical scanning direction. Temperature near the first lens is maintained higher than that near the second lens.

Abstract: A multi-beam scanning method for scanning a scanning surface with a plurality of beams which are formed into a plurality of beam spots separated from each other in a sub scanning direction includes providing n number of semiconductor laser array units, each of the n number of semiconductor laser array units having m number of light emitting points, where n is not equal to 1 and m is not equal to 1, coupling light beams emitted from the light emitting points of the semiconductor laser arrays, synthesizing the coupled beams with a beam synthesizing device to obtain m×n number of beams and deflecting the m×n number of beams at substantially the same time such that the deflected beams are impinged on the scanning surface.

Abstract: An optical scanning lens used in a multi-beam scanning optical apparatus including a first mechanism reforming the light beams into line images, a deflecting mechanism reforming the light beams into multiple scanning beams, and a second mechanism reforming the multiple scanning beams into scanning light spots running on a recording surface. The optical scanning lens has a refractive index profile and is included in the second optical mechanism, and satisfies a formula (m?1)×PLs×V/WLs?2.3×10?6, where m is a number of light emission points, PLs is a pitch of the multiple beams, V represents the refractive index profile, W [mm] represents an effective recording width of the recording surface, and WLs represents an effective range of the optical scanning lens in the sub-scanning direction corresponding to the effective recording width W. An optical scanning apparatus or image forming apparatus may use the optical scanning apparatus.

Abstract: An optical system includes three optical systems. The first has a coupling lens. The second includes a lens having a positive power in a vertical scanning direction and forms the light flux into a line image extending in the horizontal scanning direction on a deflector. The third includes a first lens having a positive power in the horizontal scanning direction, and a second lens having a positive power in the vertical scanning direction. Lateral magnification in the horizontal scanning direction is set larger than that in the vertical scanning direction. Temperature near the first lens is maintained higher than that near the second lens.

Abstract: An optical scanning apparatus reduces shading and variations in light intensity and significantly increases light usage during an optical scanning process using a simple construction in which a laser beam from a light source is deflected by a light deflector having a reflective surface and is focused to a spot upon a scanning surface by a scanning lens to thereby perform optical scanning. The light source is arranged to produce a laser beam which includes both P-polarized light and S-polarized light. A direction of polarization of the light source is inclined in a plane perpendicular to the optical axis with respect to both the deflecting direction (the Y-axis direction) and a direction perpendicular to the deflecting direction (Z-axis direction).

Abstract: A synchronous detector detects timing of scanning by an optical scanner in an image forming apparatus. The optical scanner has a light source that emits a light beam, a deflecting unit that deflects the light beam, a scanning optical element that focuses the light beam deflected by the deflecting unit onto a surface to be scanned. The synchronous detector includes a photoreceiver, and a synchronous optical element that focus the light beam deflected by the deflecting unit onto the photoreceiver. The synchronous optical element satisfies a relationship fm<fd, where fm is a composite focal length of the scanning optical element in a main scanning direction, and fd is a composite focal length of the synchronous optical element in the main scanning direction.

Abstract: In a multi-beam scanning device and method of the present invention, a semiconductor laser array having a plurality of light emitting parts emitting multiple laser beams is provided. A rotary deflector deflects the laser beams emitted by the light emitting parts of the semiconductor laser array. The deflected laser beams from the rotary deflector is focused onto a scanned surface to form a plurality of beam spots that are separated on the scanned surface in a sub-scanning direction, the scanned surface being scanned simultaneously with the plurality of beam spots in a main scanning direction by a rotation of the rotary deflector.

Abstract: A light source emitting a light flux; a coupling optical system couples the light flux from the light source to a subsequent optical system by transforming it into a parallel light flux, an approximately convergent light flux or an approximately divergent light flux; a light deflector reflects the light flux from the coupling optical system with a deflection reflective surface, and deflects it; a scanning and imaging optical system condenses the deflected light flux from the light deflector onto a surface to be scanned as a beam spot; and a correcting optical system is provided for self correcting shift of focal position of the beam spot on the surface to be scanned occurring due to environmental change or the like.

Abstract: An optical scanner has light source units spaced from each other along a first direction and having optical axes parallel to each other. Positions from which the light beams are emitted are spaced from each other by a predetermined distance at least along a predetermined direction. The optical scanner also includes a deflection unit that deflects the light beams together and scans the light beams along a second direction perpendicular to the first direction. The optical scanner also has imaging units that form an image with each of the light beams on a surface and a housing unit that holds the light source units, the deflection units, and the imaging units.

Abstract: An optical scanning device employing a scanning imaging optical system that includes a first optical system configured to receive a light flux emitted from a light source, and a second optical system configured to condense the light flux to form a long linear image in a main scanning direction in a vicinity of a deflecting surface of an optical deflector. Also includes is a third optical system configured to condense a light flux deflected by the optical deflector toward a scanned surface to form an optical beam spot on the scanned surface so that a maximum value &Dgr;Mmax and a minimum value &Dgr;Mmin of an amount of change &Dgr;M in an image-surface curvature in the main scanning direction at each image height in an effective writing region with respect to a change &Dgr;T in an environmental temperature satisfy a condition of |(&Dgr;Mmax−&Dgr;Mmin)/&Dgr;T|<0.01 (mm/° C.).