Abstract: A dynamic-pressure gas bearing structure includes a columnar shaft made of a silicon-nitride-based ceramic sintered body, a hollow cylindrical sleeve opposed to the shaft as keeping a clearance in a radial direction, the sleeve being made of a silicon-nitride-based ceramic sintered body, and at least three flat face portions located on a peripheral surface of the shaft and at equal intervals to the circumference along the peripheral surface. The flat face portion includes a plurality of unit planes continuously formed at predetermined angles to a direction of the circumference on the peripheral surface of the shaft. The unit planes are formed so as to extend substantially in parallel with an axial direction of the shaft.

Abstract: Compact raster scanner assemblies, and systems which use such assemblies, having a laser source generating laser light; a photoreceptor moving in a process direction; and a raster scanner raster sweeping the photoreceptor. The raster scanner includes a rotating polygon, an F-.theta. scan lens in the sweep plane, and a first folding mirror positioned along a first axis for reflecting laser light passing through the F-.theta. scan lens toward the photoreceptor. The first folding mirror being aligned along an axis which is at an angle with both the process direction and the resulting fast scan direction. The raster scanner assembly further including a second folding mirror for receiving laser light reflected by the first folding mirror and for directing that laser light toward the photoreceptor such that the laser light sweeps across the photoreceptor in a direction perpendicular to the process direction.

Abstract: There is provided a filter having a member of absorption material between a convex lens and a polygonal mirror. This member of absorption material is formed by coating a thin metallic film. Due to the foregoing, a predetermined transmission factor distribution can be provided. Accordingly, it is possible to correct an uneven distribution of a quantity of light on the photoreceptor caused by a change in F-number in the overfilled optical system, so that the distribution of a quantity of light can be put into practical use.

Abstract: In a raster output scanning system (ROS) of a xerographic printing device, a plurality of input optical channels direct at least one of a plurality of light beams onto separate facets of a deflector, which may be a rotating polygon mirror. The deflector deflects the light beams onto disparate optical paths. An optical system located on the disparate optical paths directs at least one of the light beams onto each of first, second, third and fourth image receiving locations. The image receiving locations may comprise a plurality of photoreceptors.

Abstract: A write start position detecting device has a curved mirror positioned in a plane in which a light beam is scanned to form a latent image on a photosensitive drum. The curved mirror is located at a position where a light beam reflected from it illuminates a photoreceptor element prior to the light source starting the writing operation. The photoreceptor element is located at a position, with respect to the curved mirror, ahead of the scanning direction in which the light beam strikes the photosensitive member to form the latent image thereon.

Abstract: A scanning optical apparatus is provided with a light source, a deflector and an aperture. A light beam generated from the light source is a linearly polarized light the polarized direction of which is inclined by 45.degree. with respect to a plane of deflection of the light beam which is defined to the light beam plane formed by the light beam deflected by the deflectively reflection surface of the deflector with the elapse of time. The light beam is scanned to be deflected by the deflector. The aperture for limiting a diameter of the light beam is arranged between the light source and the deflector.

Abstract: In a condenser optical system for a light scanning system, a single lens focuses a light beam deflected by a reflecting surface of a deflector onto a surface to be scanned and causes the deflected light to scan the surface in a main scanning direction at a constant speed. A cylindrical mirror which has a refracting power only in a sub-scanning direction normal to the main scanning direction compensates for surface tilt of the reflecting surface. At least one surface of the single lens is toric to compensate for the surface tilt associated with the cylindrical mirror and the toric surface is aspheric in a main-scanning cross-section.

Abstract: An image recording apparatus in which at least one light beam scans over an inner surface of a cylindrical member to record an image on a recording medium held on the inner surface. A light beam from light beam outputting means advances along a central axis of a cylindrical member and enters an optical head which includes deflecting means and an imaging optical system. The deflecting means and the imaging optical system rotate as one unit. The nodal point of the imaging optical system is located at or close to a point on the central axis which is nearest a beam irradiation position on the recording medium. Hence, displacement of the imaging position is prevented which makes it possible to record a high quality image, even if the optical head wobbles.

Abstract: An optical scanning system including a light source which emits a light beam; a light deflector having at least one reflecting surface providing a deflecting surface for deflecting the light beam emitted by the light source, in a deflection plane defined by the light beam incident to the light deflector and the light beam deflected by the light deflector; and a light-converging device which receives the light beam deflected by the light deflector and forms an optical image on an object to be scanned, an optical axis of the light-converging device being spaced from, and extending parallel to, the deflection plane.

Abstract: A method and an apparatus for making a moving body of material (26). The method includes the steps of directing at the moving body a high energy density beam (46,58), concentrating the beam so as to produce an illuminated spot at a location on or within the moving body, and moving the spot in accordance with the resultant of two components of movement, the first component being equal to the velocity of the moving body and the second component being relative to the moving body, so as to create a mark of a predetermined shape. In a preferred embodiment, the apparatus includes at least one movable galvanometer mirror (68,70) capable of moving the spot in accordance with the resultant of the two components.

Abstract: An optical scanning system includes a first lens for receiving a light beam from a light source and allowing the light beam to pass therethrough, and a polygon mirror having at least one reflection surface for deflecting the light beam from the first lens by reflecting the light beam on the reflection surface thereof. A second lens is provided for receiving the light beam from the polygon mirror and focusing the light beam on a first plane to be scanned. The second lens has a first surface facing toward the polygon mirror and a second surface facing toward the first plane.

Abstract: A double bounce passive facet tracking system uses a single passive optical component of a toroidal mirror to induce a beam of light to track a facet of a dual mirror rotating polygon. A beam focused in both the tangential and sagittal planes is reflected from a convex facet of the polygon mirror to the toroidal mirror. The toroidal mirror collimates the light beam in a tangential plane and focuses the beam in the sagittal plane so that the beam is collimated in the tangential plane and focussed in the sagittal plane when it reaches the flat facet of the polygon mirror.

Abstract: A scanning optical system including a light deflector rotating about a rotational axis perpendicular to a main scanning direction, a laser beam emitter for emitting a laser beam which scans a scanning surface along the main scanning direction and for making the laser beam incident upon the light deflector with a first angle with respect to a sub-scanning direction perpendicular to the main scanning direction, a curved mirror having a curvature at least along the main scanning direction for reflecting a laser beam deflected by the light deflector with a second angle with respect to an incident laser beam upon the curved mirror, and an anamorphic lens disposed between the curved mirror and the scanning surface. The anamorphic lens has a first surface having a first aspherical surface along the main scanning direction, and a second surface having a second aspherical surface which is not rotationally symmetrical about an optical axis of the anamorphic lens.

Abstract: An image recording apparatus and method use an acoustooptic element as a shutter element and as a device to scan two different beams. The beams are diffracted by modulating the acoustooptic frequency of the acoustooptic element to form band-shaped spot rows on a moving image recording medium. The spot rows include a first beam row and a second beam row that are incident on the image recording medium at different times. The positions of the adjacent beam spots of the first beam row are adjusted relative to the positions of the adjacent beam spots of the second beam row.

Abstract: An optical scanning device includes a laser source, an optical deflector which deflects scanning beams emitted from the laser source in a main scanning direction toward an object to be scanned, and a reflecting mirror which reflects the scanning beams. A beam detector which receives the scanning beams reflected by the reflecting mirror and a correcting lens which is provided between the reflecting mirror and the beam detector and which has a power at least in the main scanning direction are also provided. An adjusting lens holder is provided for adjusting the position of the correcting lens in the main scanning direction upon assembly so that an incident timing of the scanning beams onto the beam detector can be adjusted.

Abstract: An improved laser scanner has a scanning lens composed of a single lens element and at least one surface of that lens element is of such a geometry that the curvature in a direction normal to the scanning direction varies gradually in the scanning direction in accordance with the specific deflecting face of an optical deflector. This laser scanner experiences less curvature of the image plane and achieves high resolution.

Abstract: This invention relates to a laser irradiation device of laser printers in which has a simplified laser diode excitation control device, comprising a laser beam emitter, a first lens for converting the laser beam emitted from the laser beam emitter into parallel laser beam, a polygonal mirror for reflecting the parallel laser beam, the polygonal mirror being rotated and having a plurality of reflection surfaces and sensing part, the sensing part sensing the starting points of each reflection surfaces, a second lens for receiving the laser beam reflected by the polygonal mL-Tor, and a controller for synthesizing an output signal from the sensing part of the polygonal mirror with a picture signal and generating control signal to control the laser beam emitter.

Abstract: A scanning image forming optical system has a conjugate lateral magnification smaller than one with respect to a cross scan-corresponding direction. The optical scanner has an opening member arranged between a light source device and a deflecting-reflecting face of an optical deflector. The opening member interrupts a peripheral portion of a laser beam while the laser beam passes through an opening portion. A position of the opening member is determined such that .DELTA./L.gtoreq.0.32. Where L is a distance between a deflected light beam deflected by the optical deflector and an image formed, and .DELTA. is a distance between the image forming point and a conjugate image of the opening member. With this arrangement, it is possible to effectively reduce an influence of diffraction caused by the opening member, such as an aperture, and reduce a change in diameter of a light spot with respect to a defocusing amount.

Abstract: A synthetic resin lens for an optical system of a scanning optical system comprises a synthetic resin lens having a guide hole for an adhesive curing promoting light formed at a mount area thereof.

Abstract: A laser beam scanner is composed of an optical source, a beam deflector for deflecting the beam emitted from the optical source and a sensitive drum for performing printing and photosensitive processes from the beam after its deflection by the beam deflector. Also, the laser beam scanner comprises an f-.theta. lens between the beam deflector and sensitive drum for increasing resolution. The f-.theta. lens is composed of a first lens for correcting aberrations and a second lens for correcting the deflected beam passed through the first lens. The f-.theta. lens is made of plastic whose cost is lower than that of glass and can be easily manufactured since the beam emitting surface of the f-.theta. lens is spherical.

Abstract: A copying machine for forming an image by scanning a laser beam which is emitted from an optical system on a photosensitive member. Photosensors are provided at optically equivalent positions to a beginning portion and an end portion of a scanning line on a photosensitive member. A scanning time of a laser beam in the main scanning direction is measured by these photosensors. The measured time and a standard time for a copy magnification set by an operator are compared, and a correction value is calculated, and at the same time, magnification in the main scanning direction is corrected using the correcting value. Also, focusing (adjusting of the beam diameter) is carried out using the photosensors. Each of the photosensors contains a photoelectric transfer element, and a beam which comes through a slit is incident to the element. Each photosensor is provided with two slits. One is perpendicular to the main scanning direction, and the other is inclined to the main scanning direction.

Abstract: A passive facet tracking system using passive optical components to induce a beam of light to track a facet of a rotating mirror polygon. The properties of the passive components are such that they collimate a light beam in a tangential plane in a complete trip through the passive optical components and the passive optical components focus the beam in the sagittal plane so that the beam is collimated in the tangential plane and focussed in the sagittal plane when it arrives at the center of the facet.

Abstract: A laser beam scanning apparatus includes: a light source unit for emitting a collimated laser light beam; a rotary deflector unit for deflecting a laser light beam from the light source unit; a focusing unit for converting the deflected light beam into a convergent light beam, and for focusing the convergent light beam on a recording medium as a light spot, so that the focused light beam scans the recording medium in a main scanning direction when the rotary deflector unit is rotated; and a beam shape control unit for changing the sectional shape of a laser light beam emitted by the light source unit to a first sectional shape by restricting the laser light beam by using an opening of the beam shape control unit, the opening of the beam shape control unit having a predetermined sectional shape and dimensions, so that a diameter of the light spot on the recording medium is changed to a desired diameter.

Abstract: A light scanning device for scanning a scanned medium in a main scanning direction with a light beam has a detachable scanning unit having a reflecting mirror and a resonant light deflector. The scanning unit has a first adjusting mechanism for tilting the reflecting mirror about one axis to correct for a bow and an offset of a scanning line on the scanned medium in an auxiliary scanning direction substantially perpendicular to the main scanning direction, and a second adjusting mechanism for tilting the resonant light deflector about two axes to correct for a bow, a lean and an offset, respectively, of the scanning line on the scanned medium. When the resonant light deflector is to be replaced, the scanning unit is replaced with a new scanning unit which has already been adjusted. Therefore, the whole process of replacing the scanning unit can easily and quickly be carried out.

Abstract: An optical scanning system which converges light flux on a photoconductive member by an optical scanning lens after the light flux from a light source is coupled by a coupling lens (a condensing lens) and reflected by a polygonal mirror. The optical scanning system includes an area light emission source, the area light emission source and the photoconductive member being provided with geometrically-optically conjugate relations.

Abstract: A scanning optical system has a beam of light which is deflected by a light deflector and which scans a scanning surface along a main scanning direction through a scanning lens system. The scanning lens system includes an anamorphic lens made of glass which has a positive power in both the main scanning direction and in a sub-scanning direction perpendicular to the main scanning direction. The positive power in the sub-scanning direction is larger than the positive power in the main scanning direction. Also included is a plastic lens having an aspherical surface in the main scanning direction.

Abstract: In an overfilled polygon ROS architecture, fast scan jitter is reduced by uniformly illuminating the overfilled facets. In one embodiment, the collimator lens is designed with a long focal length to transmit only the more uniform central portion of the Gaussian shaped intensity profile output of a laser diode. In another embodiment, the light level at the polygon facet is made uniform by introducing a variable transmission filter along the optical path.

Abstract: A light beam scanning apparatus for recording an image on a photosensitive material by scanning with an light beam having image information of the image.

Abstract: An optical beam scanning apparatus which includes: an optical modulator which emits an optical beam in a direction corresponding to the frequency of an inputted signal; scanning device for scanning the optical beam; a scanning lens; a storage device which stores data for correcting the displacement of the optical beam passing through the scanning lens caused by an aberration of the scanning lens for each scanning position of the optical beam; and a device which, based on the data stored in the storage device, alters the frequency of the signal to be inputted to the optical modulator for each scanning position of the optical beam so as to correct the displacement of the optical beam caused by the aberration of the scanning lens.

Abstract: A rotatable aperture is positioned between the pre-polygon cross-scan cylindrical optical element and the rotating polygon mirror of a laser diode flying spot raster scanner optical system. Rotating the aperture about a line parallel to the axis in the scan plane adjusts the cross-scan resolution of the imaged spot size along the scan line of the raster output scanner optical system.

Abstract: A system for eliminating differential scan line bow from raster output scanners aligns at least the chief exit ray of each scanning light beam with the system axis. By aligning the chief exit rays to be essentially parallel to the system axis, the overall bow is reduced, and the bow of different scan lines is essentially identical. Thus, bowed scan lines from different stations in a multi-station printer, or from different passes in a multi-pass printer are generally identical and aligned.

Abstract: An optical scanning system wherein a moving cylinder supporting a segment of recording media on its inner surface is axially moved over a pair of fixed cylinders. A slit is provided between the fixed cylinders, and a light beam is radially scanned by the system through and along the slit to scan the surface of the supported segment of media as the moving cylinder moves in an axial direction over the fixed cylinders and across the slit. A pressure source provides air to the moving cylinder, with the supplied air expelled from an inner surface of the moving cylinder against the fixed cylinders to form an air bearing. Air is also expelled into the area between the fixed and moving cylinders to float the media therein during media advancement. A vacuum source is also provided to draw air through the moving cylinder from the area between the fixed and moving cylinders holding the media against the inner surface of the moving cylinder while the media is being scanned by the light beam.

Abstract: An optical scanning device for leading a laser beam emitted from a semiconductor laser diode through a collimator lens, an imaging lens, and a cylindrical lens to a plurality of reflecting surfaces of a rotatable polygon mirror, and scanning a surface to be scanned movable in a vertical scanning direction with the laser beam reflected on the reflecting surfaces of the polygon mirror and transmitted through a correcting lens. The optical centers of the semiconductor laser diode, the collimator lens, the cylindrical lens, a return mirror, and the correcting lens are located in a plane containing an axis of rotation of the polygon mirror. The semiconductor laser diode, the collimator lens, and the cylindrical lens are located over an upper surface of the polygon mirror. Accordingly, an optical system can be formed in symmetry with respect to a center axis of an optical path of a horizontal scanning light beam from the polygon mirror without interference of the semiconductor laser diode, etc.

Abstract: A method for the exposure of photo-sensitive material to be exposed (1) is performed inside of a casing (2) sealed against light from an external light source. The material to be exposed (1) is placed in a circular arc-shaped plane (3) having a uniform distance to a center longitudinal axis (4). Laser light beams (10), derived from the laser beam (6) of a laser generator (5) and deflected with a rotatable mirror (9), are providing exposure spots on the material to be exposed (1) with point-shaped signals. The recording speed is doubled or, respectively, an image or text composition is processed in half the time previously required by deflecting the light beams (10), exiting in parallel to an axis from the collimator (8), onto at least two mirror faces (12a and 12b), disposed at an angle (11) relative to the center median axis (4).

Abstract: A passive facet tracking system using passive optical components to induce a beam of light to track a facet of a rotating mirror polygon. The properties of the passive components are such that they collimate a light beam in a tangential plane in a complete trip through the passive optical components and the passive optical components focus the beam in the sagittal plane so that the beam is collimated in the tangential plane and focussed in the sagittal plane when it arrives at the center of the facet.

Abstract: An image forming apparatus comprising a laser optical system for optical scanning on a photosensitive drum. The laser optical system comprises a polygon mirror having mirror surfaces with an inclination of an angle .theta.. The polygon mirror is rotated with each mirror surface inclined by the angle .theta. to a line normal to the scanning plane, while the incident light beams to the polygon mirror are inclined by an angle 2.theta. to the scanning plane, so as to compensate the inclination of the mirror surfaces of the polygon mirror. In this way, the polygon mirror can be easily manufactured by plastic molding without damaging the mirror surfaces.

Abstract: A passive facet tracking scan angle doubling system using passive optical components to induce a beam of light to track a facet of a rotating mirror polygon and to increase the scanning angle available from a rotating mirror polygon of a given size. The passive facet tracking portion of the system using passive optical components to induce a beam of light to track a facet of a rotating mirror polygon. The properties of the passive components are such that they collimate a light beam in a tangential plane in a complete trip through the passive optical components and the passive optical components focus the beam in the sagittal plane so that the beam is collimated in the tangential plane and focussed in the sagittal plane when it arrives at the center of the flat facet. The scan angle doubling portion of the system using a rotating mirror polygon, a cylinder mirror, and a lens to increase the scanning angle available from a rotating mirror polygon of a given size.

Abstract: A plural-beam scanning optical apparatus comprises a light source having a plurality of light emitting portions, a first optical system for converting a plurality of divergent light beams from the light source into parallel light beams, a light deflector for deflecting the plurality of light beams from the first optical system, a stop disposed between the first optical system and the light deflector, and a second optical system for condensing the plurality of light beams deflected by the light deflector on a scanned surface. The plurality of light emitting portions are arranged in a direction oblique with respect to the main scanning direction of the light beams on the scanned surface. The apparatus satisfies the following condition:d/2.multidot.(n-1).multidot.L/f<0.