Abstract: A mirror surface for deflecting an incident light beam is inclined to the axis of rotation and rotated for scanning the light beam. The incident light beam is applied to the mirror surface along the axis of rotation, and a reflected light beam is continuously deflected by the rotating mirror surface to scan a surface. When the incident light beam has an elliptical cross section in a direction normal to its optical axis, the cross-sectional shape of the reflected light beam varies due to the inclination of the mirror surface in response to rotation of the mirror surface. The varying shape of the reflected light beam obstructs proper reading and writing of an image with a light scanning device employing the above mirror surface. To avoid this problem, light beam shapers are provided in positions before and after the light beam is reflected by the mirror surface.

Abstract: A light beam scanning device has a light source, a condenser optical system, a light beam deflector, and a light beam scanning lens. The light source radiates a light beam which is converted by the condenser optical system. The convergent light beam is then deflected at a constant angular velocity by the light beam deflector. The light beam scanning lens comprises a single lens, and the convergent light beam deflected by the light beam deflector is applied to the light beam scanning lens. The light beam scanning lens places the path of movement, caused by the light beam deflector, of a naturally focused spot where the convergent light beam converged by the condenser optical system is focused, and the scanned surface in substantially conjugate relationship. The light beam scanning lens also scans the scanned surface with the light beam at an approximately constant velocity.

Abstract: An optical scanning system using a laser diode array includes a collimator lens, a first imaging optical system being afocal in a deflection plane for imaging a plurality of beams from the collimator lens into respective lines in a plane perpendicular to the deflection plane, a deflector having a deflection/reflection surface, for deflecting beams from the first imaging optical system, and a second imaging optical system for focusing beams from the deflector on a scanned surface.

Abstract: This invention relates to an f.theta. lens for scanning a laser beam whose deflection half-angle reaches 30.degree.. If a deflection angle increases, the curvature of field and f.theta. characteristic are rapidly deteriorated. According to the present invention, the f.theta. lens is composed of two lenses. A first lens near a beam deflection point is formed by a meniscus lens substantially in the form of a concentric spherical surface. A power of the lens and a length between a common center of two refractive surfaces and a beam deflection point are suitably selected to well-correct the curvature of field and f.theta. characteristic over a wide scanning angle.

Abstract: A post-objective type optical deflector, in which luminous fluxes are condensed by a convergent lens and thereafter deflected by a polygonal mirror, among apparatuses for scanning a laser beam, involves a problem in the deterioration of the curvature of field and the f.theta. characteristic. The deterioration of the curvature of field and the f.theta. characteristic may be corrected by forming a reflecting surface of a polygonal mirror into a convex surface or a convex cylindrical surface and adequately selecting the relationship between the distance A from the rotational center to the center of the reflecting surface, the radius of curvature R of the reflecting surface, the distance Lo from the deflection point of the polygonal mirror to the scanning surface, and the scanning width Yo.

Abstract: An optical beam scanning system which is employed as an optical scanning means for writing or reading information with a laser beam includes a lens disposed in front of a light deflector with respect to the path of travel of the laser beam. The lens has an optical axis normal to the axis of rotation or angular movement of the light deflector. The lens is arranged such that the laser beam will be applied thereto parallel to the optial axis thereof and at a suitable lens height thereon. The laser beam that has reached the light deflector through the lens is reflected as a scanning light beam as the light deflector rotates or is angularly moved.

Abstract: A lens system for use in a light beam scanner for deflecting a monochromatic or quasi-monochromatic light beam, the lens system being disposed between a deflection point about which the light beam is deflected and a surface to be scanned in the light beam scanner. The lens system comprises an f.theta. lens and a corrective lens. The f.theta. lens comprises two positive-meniscus lenses with their concave surfaces directed toward the deflection point, the f.theta. lens having an effective deflection angle of at least 50 degrees. The corrective lens cooperates with the f.theta. lens in constituting a surface irregularity correcting optical system and is disposed between the f.theta. lens and the surface to be scanned. The corrective lens comprises a toroidal lens capable of correcting surface irregularity and curvature of field.

Abstract: An f.theta. lens for use in a light beam scanner for deflecting a monochromatic or quasi-monochromatic light beam. The f.theta. lens comprises two positive-meniscus lenses having concave surfaces directed to a deflection point about which the light beam is deflected. The lenses have lens surfaces having radii of curvature R1, R2, R3, R4 in order from the deflection point, and have a combined focal length f, the f.theta.

Abstract: An F.theta. lens is provided for focusing a laser beam, which is deflected at a constant angular speed, onto a surface being scanned in a manner such that the focused spots moves across the surface being scanned at a constant speed and linearly. The lens is formed by a single meniscus lens having a positive power and having its concave side directed toward an object.

Abstract: A post-objective type scanning device which effects scanning after a beam has been formed into a condenser light flux by an optical deflector used for laser printers or the like includes a focusing cylindrical lens in the vicinity of the scanning surface. The cylindrical lens and scanning surface are arranged to provide a geometric optically conjugate perpendicular to the scanning line so as to correct irregularities in the scanning line and to reduce the curvature of the resulting image surface.

Abstract: A laser beam optical system used under the condition that an optical axis of a lens is arranged to be inclined with respect to an incident laser beam, and an effective focal length of the lens is made shorter than a focal length with respect to an on-axis light beam. A mirror lens with one surface designed as a plane reflective mirror is used for ease of manufacture. In addition, if the mirror lens is used as a cylindrical lens for the photodeflector of the system, the lens surface can be directed downwardly to remove a ghost image and prevent accumulation of dust.

Abstract: An f.theta. lens is provided for use in an optical scanner including a deflection unit for deflecting a beam of light at substantially uniform angular rate, first optics for causing the inciddence of a beam which is elliptical in cross section and has a principal axis substantially parallel to a deflecting plane defined by the deflection unit and adapted to be focused in a direction orthogonal to the principal axis, a surface being scanned, and second optics having an f.theta. characteristic for focusing the beam onto the surface and causing it to scan the surface substantially at uniform rate as the beam is deflected by the deflection unit. The two-element lens group includes a meniscus single lens having an f.theta. characteristic and having a positive power and having its concave surface directed toward the deflection unit. Also included is a cylindrical lens having a positive power in a plane perpendicular to the deflecting plane.

Abstract: An electrophotographic copying machine capable of making a two-dimensional copy either from a two-dimensional or three-dimensional object is provided. In accordance with the present invention, if a three-dimensional object has portions which cannot be brought into contact with the top surface of the contact glass plate of the copying machine, adjusting means adjusts the focal distance to the location of such non-contact portions. The adjusting means may be any element of the optical system which is constructed to be shiftable to change the focal distance to a point of interest above the contact glass plate. Alternatively, the adjusting means may include a new element additional to the optical system.

Abstract: In an electrostatic copying machine, a light source radiates an elongated, narrow beam of light onto an original document which is moved perpendicular to the beam of light for scanning. A plurality of imaging optical fibers are arranged in a row extending coextensively parallel to the light beam, which focus images of adjacent portions of the document onto a photoconductive member which is moved in a manner conjugate to the original document for scanningly forming an image of the document on the photoconductive member. The imaging optical fibers themselves extend parallel or at an angle to the document. First and second reflectors which may be mirrors or prisms are disposed between the document and imaging optical fibers and between the imaging optical fibers and the photoconductive member respectively to deflect the optical paths of the images.

Abstract: In an electrostatic copying machine, an original document is scanned by moving an original document over an illuminated slit. The system for illuminating the slit comprises an elongated light source and a first elliptic cylindrical mirror having a focus coincident with the axis of the light source to reflect light from the source into the slit. A second elliptic cylindrical mirror has a focus common with the first mirror and reflects light from the source parallel to the slit. A plane mirror reflects the light reflected from the second mirror into the slit.