Abstract: An optical scanner assembly includes a plurality of laser beams emitted from a laser light source reflected by a polygonal mirror and incident upon a multi-sided splitter mirror containing two adjacent reflective sides of a polygon, such as a square. The top of the multi-sided splitter mirror is arranged on the incidence center axis, and the aforementioned plurality of laser beams are split to be incident upon two reflective surfaces with the top interposed therebetween.

Abstract: In a light-scanning optical system comprising a laser light source 11, a collimating lens 12, a first imaging optical system 1, a second imaging optical system 2, and a surface 19 to be scanned, the second imaging optical system 2 comprises, successively from the light-deflecting/reflecting surface side, a toric first lens 16 in which both sections in the main-scanning direction and in the sub-scanning direction have a positive power, a second lens 17 in which both surfaces are aspheric, and a third lens 18 having a positive power only in the cross section in the sub-scanning direction. As a consequence, the absolute value of imaging magnification of the second imaging optical system 2 between the light-deflecting/reflecting surface 15 and the surface 19 to be scanned in the cross section in the sub-scanning direction becomes 1 to 2, whereby the light-scanning optical system has a wobble-correcting function which is also applicable to apparatus having a relatively long scanning length.

Abstract: In an optical scanning apparatus for causing a luminous flux from a rotary polygon mirror 4 to form an image on a surface to be scanned 6, a concave lens 5a functions not only as one constituent of an f .theta. lens with respect to the luminous flux scanned by the rotary polygon mirror 4 but also as a cylindrical lens for forming a linear image in the vicinity of a deflecting and reflecting surface of the rotary polygon mirror 4 with respect to a luminous flux from a laser light source 1. The luminous flux directed from the light source 1 to the rotary polygon mirror 4 is passed through the concave lens 5a such as to intersect the optical axis of the f .theta. lens.

Abstract: A first lens made of a positive meniscus lens having a convex surface directed onto the object side, a second lens made of a biconcave lens, and a third lens made of a biconvex lens are successively disposed from the object side, and predetermined conditional expressions are satisfied, thus yielding an image readout imaging lens suitable for reading out the shorter side of A4--sized color originals and the like. Successively from the object side, a first lens L.sub.1 made of a positive meniscus lens having a convex surface directed onto the object side, a second lens L.sub.2 made of a biconcave lens, and a third lens L.sub.3 made of a biconvex lens are disposed, and the following conditional expressions (1) to (5) are satisfied:-0.36f<f.sub.2 <-0.25f (1)-1.07<f.sub.2 /f.sub.3 <-0.74 (2)0.26f<r.sub.4 <0.32f (3)0.43<r.sub.4 /r.sub.5 <0.77 (4)0.82<r.sub.1 /r.sub.4 <1.

Abstract: In an imaging lens suitable for image reading of a four-lens element configuration comprising, successively from the object side, positive, positive, negative, and positive lenses, at least one surface of the fourth lens is made aspherical, whereby lighter weight and lower cost are achieved, while various kinds of aberration are corrected. The four-lens element imaging lens comprises, successively from the object side, positive first and second lenses L.sub.1 and L.sub.2 each having a surface on the object side convex toward the object side, a negative third lens L.sub.3 having a surface on the image side concave toward the image side, and a positive fourth lens L.sub.4 having at least one aspheric surface.

Abstract: Positive first and second lenses each having a convex surface directed onto the object side, a negative third lens having a concave surface directed onto an image side, a negative fourth lens having a concave surface directed onto the object side, and positive fifth and sixth lenses each having a convex surface directed onto the image side are successively disposed from the object side, and predetermined conditional expressions are satisfied, thus yielding an image readout imaging lens suitable for reading out color originals. Successively from the object side, positive first and second lenses L1 and L2 each having a convex surface directed onto the object side, a negative third lens L3 having a concave surface directed onto an image side, a negative fourth lens L4 having a concave surface directed onto the object side, and positive fifth and sixth lenses L5 and L6 each having a convex surface directed onto the image side are disposed, and the following conditional expressions (1) to (6) are satisfied:Nda+0.

Abstract: A four-element lens configuration of positive, negative, positive, and negative satisfies predetermined conditional expressions, thereby correcting various kinds of aberration and achieving compactness and wider angle of view in a readout lens system. Further, without using an expensive glass material, higher image quality is attained. Successively from the object side, a first lens L.sub.1 made of a positive meniscus lens having a convex surface directed onto the object side, a second lens L.sub.2 made of a biconcave lens, a third lens L.sub.3 made of a biconvex lens, and a fourth lens L.sub.4 made of a negative meniscus lens having a convex surface directed onto the imaging surface side are arranged and configured so as to satisfy the following conditional expressions:-5.5<f.sub.12 /f<-2.8 (1)0.36<f.sub.3 /f<0.46 (2)-1.14<f.sub.2 /f.sub.3 <-0.8 (3)-8.8<f.sub.4 /D.sub.6 <-6.0 (4)0.23<R.sub.1 /f<0.

Abstract: Through an imaging lens, respective luminous fluxes from a semiconductor laser array light source comprising a plurality of semiconductor laser devices arranged in a row form images on a photosensitive surface, thereby effecting light dot formation (light scanning) on a surface to be scanned without using mechanical light-scanning means such as polygon mirror. The laser printer apparatus comprises a semiconductor laser array light source (1) composed of a number of semiconductor laser devices (light-emitting devices; 1a) arranged in a row, and an imaging lens (3) for forming images of the luminous fluxes from the respective light-emitting devices (1a) in a row on a photosensitive surface (2). The semiconductor laser array light source (1) comprises not less than 700 pieces of minute semiconductor laser devices (1a) arranged in a row and is adapted to modulate laser beams from the respective devices (1a) independently of each other.

Abstract: In a light scanning optical system comprising a first imaging optical system, a deflector, and a second imaging optical system successively toward a surface to be scanned; the second imaging optical system comprises, successively from the deflector side, an imaging lens, a concave cylindrical lens having a power only in a direction substantially orthogonal to the scanning direction, and a negative cylindrical lens having a power only in a direction substantially orthogonal to the scanning direction, in order to reduce the size and cost of apparatus. The light scanning optical system comprises, successively from the light source side, a first lens (1), a deflector (2), second and third lenses (3, 4), a concave cylindrical mirror (5), and a negative cylindrical lens (6). Each of the concave cylindrical mirror (5) and negative cylindrical lens (6) has a power only in a direction orthogonal to the main-scanning direction on a surface (7) to be scanned.

Abstract: An f.multidot..theta. lens for an optical scanning system is comprised of four lens elements, arranged in order from the object end to the image end: a first meniscus element of positive power having a concave object side surface, a second element of negative power having a concave object side surface, a third element of positive power having a convex image side surface and a fourth element.

Abstract: With a stop disposed at the center, a lens system are composed of four sheets of positive, negative, negative, and positive lenses. At the time of variable magnification, the whole lens system is moved while distances between the lenses are changed, whereby a low cost and a compact size are attained in a zoom lens system for copying. This lens system is constituted by four sheets of positive, negative, negative, and positive lenses (L.sub.1 to L.sub.4) which are disposed in pairs laterally symmetrical to each other with respect to the stop. At the time of reducing or enlarging, the distance between the first lens (L.sub.1) and second lens (L.sub.2), the distance between the third lens (L.sub.3) and fourth lens (L.sub.4), and the distance between the second lens (L.sub.2) and third lens (L.sub.

Abstract: A collimator lens system for collimating diverging light bundle emitted from a light source into a parallel light bundle includes first to third lens elements arranged in this order from the side of the parallel light bundle. The first lens to third elements are a positive double-convex lens, a negative lens concave to the side of the parallel light bundle and a positive lens convex to the side of the parallel light bundle, respectively. The following formulae (1) to (5) are satisfied0.8<f.sub.1 /f.sub.3 <2.0 (1)1.5<{r.sub.2 (n.sub.2 -1)}/{r.sub.3 (n.sub.1 -1)}<2.7 (2)0.8<r.sub.5 /{f(n.sub.3 -1)}<1.4 (3)0.8<-r.sub.1 /r.sub.2 <2.4 (4)0.5<-f.sub.2 /f<6.0 (5)wherein f represents the overall focal length of the collimator lens system, f.sub.i represents the focal length of i-th lens element, i standing for 1, 2 or 3, r.sub.i represents the radius of curvature of i-th refracting surface as numbered from the side of the parallel light bundle, i standing for 1, 2, 3, 4, 5 or 6 and n.

Abstract: A copy lens comprising four lens elements arranged symmetrically with an aperture, namely, in order from the object end to the image end, a first biconvex element and a biconcave element, which are positioned on one side of the aperture, a third biconcave element identical with the second biconcave element and a fourth biconvex element identical with the first biconvex element, which are positioned on another side of the aperture.

Abstract: An imagery lens system for image reading consists of first to fourth lens elements which are arranged in this order from the object side. The first and fourth lens elements respectively are double-convex lenses, and the second and third lens elements respectively are double-concave lenses. The following formulae are satisfied.0.35<f1/f<0.51--(1)0.34<f4/f<0.45--(2)0.11<d7/f<0.16--(3)0.29<d/f<0.41--(4)wherein f represents the synthetic focal length of the overall lens system, f1 represents the focal length of the first lens element, f4 represents the focal length of the fourth lens element, d represents the axial surface separation between the object side face of the first lens element and the image side face of the fourth lens element and d7 represents the central thicknesses of the fourth lens element.

Abstract: A compact scanning optical system for effecting a superior tilt surface correction and for reducing a field curvature. The system is provided with a focusing optical system which is composed of a first single lens and a second single lens, wherein the first single lens, with a positive refracting power in a plane of scan, has a toric surface from an image plane and the second single lens, with a negative refracting power in the scan plane, has an aspherical lens.

Abstract: An optical scanning system for use in a laser printer, including a first light receiving section for controlling a scan timing and a second light receiving section for controlling the amount of scanning beam. The first light receiving section is composed of two light receiving elements, wherein they are disposed remote from each other at outsides external to both ends of an effective scan field. The second light receiving section is a single light receiving element disposed in close proximity to either of the first light receiving elements in the same scan plane. In the system, there is further provided a laser beam splitter between a light source and the combination of the first light receiving element and the second light receiving element for diffracting the laser beam into the 0th order light and the +1st order light, the former entering the first light receiving element whilst the latter entering the second light receiving element.

Abstract: An optical beam scanner capable of correcting irregularities in pitch of beam scanning as caused by inclination or angular deviations of reflective deflection surfaces of a deflector, the scanner including a first image-forming optical system arranged to form an image of a light beam from a light source linearly on or in the vicinity of a reflective deflection surface of a deflector, and a second image-forming optical system arranged to form an image of the deflected light beam from the deflector on a scanning surface. The second image-forming optical system is constituted, successively from the side of the deflector, by a first singular lens element provided with at least one toric surface and having positive refractive power in a plane of transverse main scan direction, and a second singular lens element provided with either a spherical or cylindrical surface and having negative refractive power in the plane of the main scan direction.

Abstract: A plastic objective lens system comprises at least one convex lens constituted of a plastic material exhibiting a relatively small absolute value of the coefficient of change in refractive index with temperature, and at least one concave lens constituted of a plastic material exhibiting an absolute value of the coefficient of change in refractive index with temperature, which is larger than the absolute value of the coefficient of the plastic material constituting the convex lens. A reflecting surface concave to the object and image side may be positioned at the rear of the convex lens and concave lens. The plastic objective lens system decreases fluctuation of the focal length and the conjugate distance due to a change in temperature while aberration is minimized.