Abstract: In an electrophotographic copying apparatus, reflected light from an original subject is directed to a light receiving means, such as a photoconductive drum, through a slit. The apparatus includes an optical device, for example a zoom lens, positioned between the original subject and the photoconductive drum for varying the size of the optical image being passed through the slit. A shading board fixed adjacent to the photoconductive drum extends along a longitudinal direction of the optical image.

Abstract: The present invention is a tear production measuring sheet that has a pair of measuring strips adapted to be used for the right and left eyes and is disposed side by side in such a manner that the strips have a common scale. Each of the measuring strips is separated from the measuring sheet by a cut formed in the measuring sheet so as to extend around the measuring strip, except for a connection between the measuring strip and the sheet.

Abstract: A recording and/or reproducing apparatus includes a cartridge receiving holder, a cartridge shutter opening device for opening a laterally slideable shutter of a disc cartridge along with insertion thereof into the holder, a mount base displaceable between a retracted position away from the holder and an operative position in which a head and spindle motor mounted on the base will be made operative with respect to a disc contained in the full-loaded disc cartridge in the holder. The disc cartridge is retained in the full-loaded position in the holder through engagement between a lock lever rotatably mounted on the holder and a notch formed on the side periphery of the disc cartridge. The lock lever is normally biased by a spring to direct outwardly so that the disc cartridge is free from contract with the lock lever during insertion into the holder.

Abstract: A device for opening a shutter of a disc cartridge along with insertion of the disc cartridge into a holder of a recording and/or reproducing apparatus for performing recording and/or reproducing operation is disclosed. The device includes at least one arm member freely rotatable about a pivot provided at one end thereof and having at the other end a first engaging portion adapted to be in engagement with the shutter substantially during insertion of the disc cartridge. A guide means or a slot extending in an oblique direction between the cartridge inserting direction and a direction in which said shutter is slided to open is provided for guiding therealong a second engaging portion of the arm member during first-step advancement of the disc cartridge into the holder from an unloaded position to a half-loaded position, thereby rotating the arm member to open the shutter due to continued engagement thereof with the first engaging portion.

Abstract: An optical device for varying magnification, having an object plane on which an object is to be located, a light receiving surface, and an imaging lens unit for focusing an image of the object located on the object plane onto the light receiving surface, so that upon varying the magnification, an optical distance between the object plane and the light receiving surface can be changed, wherein the imaging lens unit includes a main lens group and a correcting lens group that are movable relative to each other, the main lens group or the correcting lens group being fixed with respect to the light receiving surface, the correcting lens group or the main lens group being movable to the object plane and the light receiving surface to vary the magification.

Abstract: A device for opening a shutter of a disc cartridge along with insertion of the disc cartridge into a holder of a recording and/or reproducing apparatus for performing recording and/or reproducing operation is disclosed. The device includes at least one arm member freely rotatable about a pivot provided at one end thereof and having at the other end a first engaging portion adapted to be in engagement with the shutter substantially during insertion of the disc cartridge. A guide means or a slot extending in an oblique direction between the cartridge inserting direction and a direction in which said shutter is slided to open is provided for guiding therealong a second engaging portion of the arm member during insertion of the disc cartridge, thereby rotating the arm member to open the shutter due to continued engagement thereof with the first engaging portion. The pivot of the arm member is supported by a sliding member and is moving while the second engaging portion is being guided along the first guide means.

Abstract: A long focal length, super-large aperture ratio reflecting/refractive optical system employing easily workable spherical surfaces and which is suitable for use in an astrocamera or a super-telephoto lens system. The lens system includes four optical units arranged along the optical path, including a first optical unit composed of a meniscus lens having a weak negative power, a second optical unit composed of a reflecting surface having a positive power, a third optical unit for deflecting light reflected from the second optical unit, and a fourth optical unit including at least one negative lens element.

Abstract: A zoom lens comprising a first and a second lens component that are related to each other for zooming. The first lens component consists of four lens elements and has a positive focal length f.sub.I satisfying the condition 0.35<f.sub.I /f.sub.M <0.85, where f.sub.M is the focal length of the system at unit magnification. The second lens component consists of a negative miniscus lens and possibly a positive lens and has a negative focal length f.sub.II satisfying the condition, 0.7<-f.sub.II /f.sub.M <3.0.

Abstract: A color separation optical reading apparatus having a lighting source for illuminating an object, an imaging optical system for projecting an image of the object illuminated by the lighting source, a light reception member for receiving the light image of the object through the imaging optical system, and a wavelength selection means disposed at a desired location on the optical path between the lighting source and the light receiving member. At least one optical path length correction member is provided between the object and the light receiving member so as to cooperate with the wavelength selection means to correct defocus.

Abstract: A wide-angle reading lens system is disclosed which comprises, in order from the object side, a first lens element which is a negative meniscus lens having its convex surface directed toward the object side, a second lens element which is a positive lens having a strong convex surface directed toward the object side, a third lens element which is a negative lens, and a fourth lens element which is a positive lens having an strong convex surface directed toward the image side, said lens system satisfying the following conditions:-2/0f.ltoreq.f.sub.1 .ltoreq.-0.75f (1) ##EQU1##d.sub.1-7 .ltoreq.0.85f (3)where f denotes the overall focal length of the system; f.sub.1 is the focal length of the first lens element; n.sub.i is the refractive index of an ith lens at the d-line; .nu..sub.i is the abbe number of the ith lens; and d.sub.1-7 signifies the distance from the surface of the first lens element on the object side to the surface of the fourth lens element on the image side.

Abstract: A reading lens system, such as may be used in a facsimile machine or the like, having a small size, low cost, high performance and a large aperture ratio of 1:3.2 to 1:3.5 and a half angle of 22.5.degree. or more. The lens includes, in order from the object side, a first lens element which is a positive meniscus lens having its convex surface directed toward the object side, a second lens element which is a positive meniscus lens having its convex surface directed toward the object side, a third lens element which is a negative meniscus lens having its convex surface directed toward the object wide, a fourth lens element which is a negative meniscus lens having its concave surface directed toward the object side, a fifth lens element having its concave surface directed toward the object side, and a sixth lens element which is a positive lens. The second and third lens elements are cemented to make the overall system a five-unit six-element lens configuration. The lens system satisfies0.6<.vertline.f.sub.

Abstract: A copying zoom lens system consisting of five lens elements. The first and fifth lens elements are each a single negative lens element with a negative focal length. The middle three lens elements are grouped into a central lens unit of positive focal length. The central lens unit has a positive biconvex lens surrounded by two meniscus lenses having their concave surface directed to the biconvex lens. Zooming is achieved by moving the first and fifth lens elements with respect to the central lens unit as well as by moving the overall lens system between fixed image and object planes.

Abstract: A variable magnification copying optical system for projecting an image of an object, disposed on an object surface, to a focal plane and for varying a magnification of the image with respect to the object. The optical system includes a zoom lens movable to a plurality of positions for obtaining a first range of magnification values and a second lens for obtaining a further magnification value outside of the first range. To obtain the further magnification, the second lens is effectively moved into the optical projection path by moving the lens itself, changing the projection path, e.g., by a suitable shutter, or a combination of these steps. The second lens can provide the further magnification either alone or in combination with the zoom lens.

Abstract: A focal position adjusting device for a small variable-magnification type copying machine having a zoom lens. First and second mirrors are arranged below an original holding stand, the first mirror reflecting the image of an original on the holding stand, and the second mirror reflecting the image from the first mirror towards a photosensitive drum. A zoom lens is disposed between the first and second mirrors. The zoom lens includes at least two lens groups arranged along the optical axis. The positions of these two lens groups are adjusted during the assembly of the copying machine so that the focal position falls on the surface of the original for various magnification settings.

Abstract: There is disclosed a variable-power copying lens including, successively in order from an object, a first lens group having a positive focal length and a second lens group having a negative focal length. The first and second lens groups are movable in their entirety while varying an interval therebetween to keep constant the distance between an object surface and an image-focusing surface. The first lens group comprises a first positive lens, a second negative lens, a third positive lens, a fourth negative lens, and a fifth positive lens. The second lens group comprises a sixth positive-meniscus lens having a convex surface facing an image and a seventh negative-meniscus lens having a convex surface facing the image.

Abstract: In an optical copier having a zoom lens, the first and second lens groups are positive and negative, respectively, to provide sufficient movement range for the half-speed mirrors.

Abstract: A small-size and high-performance wide-angle photographic lens system of the seven-group-seven-element type including first and second components of negative meniscus lenses with convex surfaces directed to the object, a third component of a positive lens having a large-curvature convex surface directed to the object, a fourth component of a positive lens having a large-curvature convex surface directed to the image, a fifth component of a biconcave negative lens, a sixth component of a positive meniscus lens having a convex surface directed to the image, and a seventh component of a positive lens.

Abstract: A large-aperture telephoto lens comprising seven lens elements in six lens components, the first lens component having a positive lens, the second lens component having a doublet composed of a negative-meniscus lens with its concave side facing an image and a positive-meniscus lens, the third lens component having a negative-meniscus lens with its concave side facing the image, the fourth lens having a meniscus lens with its concave side facing an object, the fifth lens component having a positive-meniscus lens with a surface of a larger curvature facing the object, and the sixth lens component having a positive lens.

Abstract: A varying magnification copying device of small size and low manufacturing cost in which a region of movement of a zoom lens system for an enlargement copying operation is shared with a region of movement of a half-speed mirror for the equal magnification and reduction copying operations. The zoom lens system is moved along the optical axis thereof by a feed screw rotated by a digitally-controlled stepping motor. The zoom lens system, which includes front and rear frames varying front and rear lens systems, is adjsuted in magnification factor by a cam and cam follower mounted on the rear and front frames, respectively. The cam is rotated by a pinion gear which is engaged with a rack which extends parallel to the feed screw. Movement of the zoom lens system perpendicular to the optical axis is accomplished through a lead cam and cam follower.

Abstract: A variable power lens system capable of both enlargement and reduction of the image of an original to be copied, in which the distance between the object and image surfaces constant. The lens system includes a first lens group having a first positive focal length and a second lens group having a negative focal length. The distance between the first and second lens groups is variable. A lens power of each lens group is increased so that a distance between the object surface and the lens is long in comparison with a distance between the lens and the image surface and at the same time the variable power ratio is greater than 2 with high performance and compactness.