Abstract: A scanner system includes a light source for producing a light beam and a multifaceted polygon for scanning the light beam in a scan plane along a scan line a predetermined distance from the polygon, such as at the surface of a photoreceptor or a document to be read. The system also includes a post-facet lens system that includes first and second elements configured to compensate for field curvature and wobble without compensating for scanner non-linearity. Preferably, the first element and second elements are so disposed that the light beam passes first through the first element and then through the second element. In addition, the first element preferably includes first and second surfaces such that the light beam passes from the first surface to the second surface, the first surface being spherical and the second surface being cylindrical with curvature in the scan plane and essential no curvature in the cross-scan plane.

Abstract: A scanner includes a light source for producing a light beam and a multifaceted polygon for directing the light beam to a spot on a surface to be scanned, such as at the surface of a photoreceptor or a document to be read, that is located at a predetermined location relative to the polygon and for moving the spot across the surface along a scan line or predetermined length. The scanner also includes a post-facet lens system with first and second elements configured to compensate for field curvature and wobble without compensating for scanner non-linearity. They are composed of plastic, the surfaces of the elements having curvature in both the scan plane and the cross-scan plane as well as less magnification than existing post-facet lens systems.

Abstract: An optical scanning system reduces wobble at the ends of the scan line by twice reflecting a laser beam off a facet of a rotating polygon mirror, then passing the beam through a cylindrical scan lens system which will focus the beam in the scan plane to the scan line and then reflecting the beam off a cylindrical mirror to focus the beam in the cross-scan plane to the scan line.

Abstract: A polygon system for correcting wobble by double reflection from the active facet without bow is disclosed. Instead of the impinging light source being transverse to the axis of rotation of a rotating polygon, this rotating polygon 12 having facets at a draft angle to the axis of rotation, a collimated light source 10 impinges upon a rotating polygon 12 with the facets 22 having the predetermined draft angle D. A., and angles of incidence at the first and second reflections. By two further relections, 18, 20, the light is then reimpinged upon the same facet; wobble is similarly corrected, but with no effects of bow.

Abstract: This invention relates to a pyramid polygon scanner without cylinder optics wherein the effects of jitter are reduced by the use of a start of scan detector situated at a predetermined angle from the normal (vertical) position. The start of scan detector is rotated about an axis through the nominal scan line. Thus, if tilt (not the draft angle) is present in the rotating polygon system and jitter is generated, the rotation angle of the split detector moves the jitter to the beginning and end of scan, leaving the center of scan free of the effects of jitter. The angle of the split detector is in approximate relation to the angle of incidence at the first reflection on the rotating polygon.

Abstract: This invention relates to a pyramid polygon scanner wherein the differential scan length between multiple beams can be eliminated by tilting the beams with respect to the photoreceptor surface. Then the beam with the shorter scan lengths when the beams are normal to the photoreceptor, travel a greater distance before they impinge on the photoreceptor. At the start or end of scan the scan angle is not zero, so the scan lengths for the beams with the larger travel distances are increased by the extra distance multiplied by the tangent of the scan angle. At the proper tilt angle, all scan lengths at the photoreceptor are the same. Since the angular scan rate of all the beams are always the same, over the entire scan, the scan lengths of the individual beams will always be the same, at any fraction of the total scan. Thus the information written onto the photoreceptor by the multiple beams will be in alignment for all simultaneous beams.

Abstract: A rotating, draft angle polygon scanner system for correcting wobble by double reflection of an infinite conjugated light beam from a pair of fixed mirrors having optical power provided by aspheric surfaces. In addition to their wobble correction function, the optical powered mirrors provide the scan and focus functions of conventional f-.theta. scan lens optics and hence such f-.theta. scan lens optics can be eliminated from the scanner system, thereby providing an all mirror scanner system.

Abstract: An internally reflecting rotating polygon system for correcting wobble by double reflection from the active facet without bow is disclosed. Instead of the impinging light source being transverse to the axis of rotation of a rotating polygon, this rotating polygon 52 having internally reflecting facets 54 at a draft angle to the axis of rotation, a collimated light source impinges upon a rotating polygon 52 with the facets 54 having the predetermined draft angle D. A., and angles of incidence at the first and second reflections. By two further reflections, 56, 58, the light is then reimpinged upon the same facet 54; wobble is similarly corrected, but with no effects of bow.

Abstract: A raster scanner system having double reflection from polygon facet surfaces which have aspheric curvature. In addition to providing a scan which is free of astigmatism and bow, the aspheric surfaces provide the scan and focus functions of conventional scan lens optics.

Abstract: A elliptical cylinder mirror system for use in a raster input scanning system which allows for high efficiency light gathering and reflection to a photosensitive device. Elliptical cylinder mirrors 10, 12 are placed adjacent to a scan line 14 on a document or other medium 8 to be scanned. The input light 38 is caused to raster scan the medium wherein the light reflected from the medium is now modulated by the information on the medium 8. One elliptical cylinder mirror 10 collects and focusses the reflected light from one side of the scan line directly onto a photosensitive or similar type of device 18. Another elliptical cylinder mirror 12 collects and reflects the light from the other side of the scan line towards a fold mirror 20 which, in turn, reflects the light toward the same or closely situated photodetector 18. A large proportion of the light reflected by the medium 8 is gathered by the mirrors 10, 12 for use in the photodetection process.

Abstract: A lens system is described which allows a scan spot in a flying spot scanning system on the image surface to be focused in the cross scan plane and at the same time correcting field curvature distortion. The use of a first lens element having negative power in the scan direction and a second lens element having positive power in the cross scan plane on the front surface and positive power in scan plane on the rear surface allows a light from a laser to be reflected from a rotating polygon to be reflected from a concave cylindrical mirror onto a xerographic or other photosensitive surface.

Abstract: A raster scanner with laser for generating a scanning beam and compact folded optical system for transmitting the beam to the object to be scanned. The optical system includes a first mirror for guiding the laser beam forward along a downwardly inclined slope to the modulator, a second mirror below the modulator for intercepting the beam from the modulator and folding the intercepted beam to guide the beam backwards along a horizontal plane to a third mirror which folds the beam and guides the beam forward along an upwardly inclined slope against the mirrored facets of a rotating polygon, the polygon scanning the beam through a preset scan arc and returning the beam via a focusing lens to the third mirror, the third mirror folding the scan beam and guiding the scan beam forward, and a fourth mirror for intercepting the scan beam and guiding the beam to the object to be scanned.

Abstract: A projection lens assembly is provided for use in a printed circuit board projection imaging system wherein a reduced image on a glass master is magnified and projected onto a photoresist coated circuit board positioned at a remote location by the assembly. The projection lens comprises eight elements having lens parameters such that the position of a hole in the glass master is projected over the entire 24.times.18 inch format of the PCB panel with minimum distortion and high optical resolution.An adjustment technique may be provided to permit adjustment of the distortion of the assembled lens without affecting the other performance parameters of the lens.

Abstract: A laser beam scanner having a positive cylinder mirror located between the polygon scanner and the photosensitive surface. The positive cylinder mirror, which has power in the sagittal (cross-scan) plane but no power in the tangential (scan) plane, minimizes scan-to-scan spot position errors due to angular alignment errors between adjacent facets of the polygon scanner without introducing significant sagittal field curvature. Residual sagittal field curvature is compensated for by providing a negative refractive cylinder lens, with power in the sagittal plane, between the cylindrical mirror and the polygon scanner.

Abstract: An all mirror facet tracking system including first and second spherical mirrors. Both of the mirrors can be located along the same system axis on opposite sides of a rotating multi-faceted polygon which has its axis of rotation on the system axis. To reduce coma, the spherical mirrors are located along orthogonal system axes and a flat folding mirror is provided between the two spherical mirrors to reduce the angle of incidence of the chief ray with the second spherical mirror.