Xerox Corporation

Edward C Bock

James J Appel

William J Nowak

Richard A Spinelli

John H Hinton

Daniel W Costanza

David K Shogren

James D Rees

James M Casella

LeRoy A Baldwin

Joachim A Ritter

Edwin Zucker

David P Wind

Charles M Burkard

John R Dennis

Raster output scanners having piezoelectric-activated lens movers comprised of a mounting base, an electrically operated piezoelectric element connected to the mounting base, a flexible linkage having a lens mount, and a lens attached to the lens mount. The flexible linkage includes flexible arms that can flex in the predominate direction of motion of the piezoelectric element, but that are substantially rigid in another direction. The flexible linkage is mounted such that the flexible arms bias the lens toward the piezoelectric element. Expansion and contraction of the piezoelectric element, combined with the bias of the flexible arms cause the lens mount and its attached lens to follow the expansion and contraction of the piezoelectric element. The rigidity of the flexible arms hold the lens in the proper focal plane. Beneficially, the piezoelectric element is driven so as to compensate for scan line position errors.

Flexible arm piezoelectric lens mover

Electrophotographic printers having raster output scanners that correct for polygon facet phasing errors and photoreceptor position errors by aerial scan line adjustments. A photoreceptor position sensor senses the position of the photoreceptor and a facet position sensor senses the position of the polygon facets. A scan line position controller produces a position signal that depends upon the photoreceptor position sensor and the facet position sensor. A piezoelectric-actuated lens mover assembly receives the position signal and moves a pre-polygon lens to adjust the scan line plane to correct for any misregistration. The piezoelectric-actuated lens mover assembly includes a large displacement piezoelectric element and a flexible arm assembly that holds the pre-polygon lens.

Aerial color registration

A raster output scanner assembly having a first laser source for producing first and second laser beams, and a second laser source for producing third a fourth laser beams. The first and second laser beams are directed to a first rotating, multifaceted polygon while the third and fourth laser beams are directed to a second rotating, multifaceted polygon. The first polygon reflects the first and second laser beams onto a moving photoreceptor while the second polygon reflects the third and fourth laser beams onto the photoreceptor. The spots produced by the various laser beams are interlaced such that the scan line produced by the third laser beam is between the scan lines produced by the first and second laser beams, while the scan line produced by the fourth laser beam is adjacent the scan line produced by the second laser beam.

Laser diode raster output scanners with interlaced scan lines

Correcting motion quality induced color banding problems resulting from photoreceptor motion defects in a color imaging device having a laser based multifaceted polygon and a rotating cylindrical mirror whose rotation is set by a controlled rotation inducing element. A motion sensor senses the motion of the photoreceptor. Based upon motion errors a controller either advances or delays the production of a latent image. The controller further controls the rotation inducing element, beneficially a piezoelectric element, such that a latent image is produced in a predetermined location. When multiple latent images are produced, the controller beneficially causes the latent images to be properly registered.

Moving mirror motion quality compensation

A system of mounting a raster output scanner relative to a photoreceptor such that deskewing, focusing, and pitch adjustment of the aerial image are possible. A spring isolated ROS assembly having at least two ROS arms attaches to a backer bar assembly that locates the position of the photoreceptor. The backer bar assembly and the ROS assembly connect at one end using a ball and socket and at the other end using a ball and fork such that the center line of the balls form a scan line plane. The ball and socket form a reference connection at one end. At the ball and socket end the photoreceptor backer bar has a mounting arm that is flexible in one plane but rigid in a perpendicular plane. A deskew mechanism, beneficially a motor driven cam, flexes the backer bar mounting arm as required to deskew the scan line.

Raster output scanner to photoreceptor mount

A Raster Output Scanner (ROS) assembly is mounted within a printing machine frame so as to maintain a very precise relationship with the photoreceptor being imaged. A ROS housing is mounted in relation to the photoreceptor so that, while the housing is fixed to a machine frame by isolators to damp out vibrations and transients, a mechanical latching to a photoreceptor backer bar provides a degree of rotational movement consistent with movement of the photoreceptor. Thus, errors created by photoreceptor motion are compensated for. The invention discloses a 3 or a 4 point mounting arrangement which affords a high degree of stability coupled with conformance with exacting registration tolerances.

Mounting arrangement for a raster output scanner

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.

Sidewinder raster output scanner

Raster output scanner assemblies, and systems which use such assemblies, having mirrors mounted on the outside of an outer frame. Slits in the outer frame enable light to reflect from the mirrors. Beneficially, the outside mirror or mirrors are protected from contamination by mounting the primary surface of the mirrors (the surface which reflects light) against the outer frame and by mounting a cover over the mirrors.

Raster output scanner having externally mounted mirrors

A single pass highlight color printer is disclosed which utilizes two pairs of Raster Output Scan (ROS) systems mounted symmetrically about a common polygon motor assembly. Four identical optical systems are thus provided, 180.degree. apart with diode laser outputs directed from a ROS frame parallel and separated to allow the appropriate spacing for xerographic components situated adjacent the xerographic belt. Each ROS unit includes a 90.degree. mirror pair which is mounted on a roof mirror carriage which in turn is connected to a focus carriage via an adjustable guide system. The interaction between the focus carriage and the roof mirror carriage enables a skew alignment and process (beam steering) adjustment to be accomplished with a high degree of precision.

Single pass color printer

An alignment mechanism is provided for adjusting the optical center line of scanning beams generated in a ROS system. The collimator lenses which collimates the output of a diode laser source are mounted within a lens barrel. The lens barrel is positioned so as to be biased against the sides of a housing in which the ROS components are located. The barrel has eccentric rings mounted along its circumference which, when rotated, inpart motion to the lens barrel so as to change the center line of the collimated beam output. This provides adjustment of the scan line center line at the image plane.

Alignment method and apparatus for optical imaging systems

In an overfilled ROS polygon architecture, stray reflection from facets adjacent the completely filled (illuminated) facet are prevented from affecting the scan line images by aligning the optical axis of the pre-polygon and post-polygon optical components at an optimum angle .phi.' so that the stray light reflections at the photoreceptor occur only at non-image forming scan times (outside the image scan time). The optimum angle .phi.' is expressed by the relationship .phi.'=2(.OMEGA..+-.1/2.theta.) where .OMEGA. is given by the expression 360/X, X being the number of scanning facets, and .theta. being the scanning angle.

Prevention of stray light reflections in a raster output scanner (ROS)

An imaging system which uses a right-to-left scanning operation is enabled by first detecting by an optical sensor the right hand edge of a document to be copied, the left edge of the document being registered at the left edge of the platen. The scanning operation is initiated at the detected right hand edge and proceeds to the left. The end of scan coincides with the left registration edge. Book copying is enabled by adding a sloping left edge to the platen placing the book to be copied over the edge corner. The optical system is rotated for a book copy mode so that light penetrating the binding area is transmitted along the optical path. This arrangement allows required pre-scan excursion to take place in the space to the right of the start of scan position, thus avoiding interference with the sloping book edge.

Right-to-left scanning system for copying documents or bound books

A document scanning system is disclosed which utilizes a scan carriage mounted on guide rails which are connected between novel support members. The support members are mounted at one location only to a fixed base support. The guide rails do not require mounting to a side frame structure; the support structure providing the stability usually provided by the sides of a frame. The guide rails are inherently stable and provide the support for the scan load components. The second embodiment of the invention uses a single guide rail to support the optical system rather than plural guide rails.

Self supporting optical document scanning system

A document registration system is disclosed which enables documents of various sizes to be registered at different corner registration positions on a platen and to be projected onto a photoreceptor so that the projected images have one side aligned along a common edge parallel to the edge of the photoreceptor. A lens drive and control circuit is provided for determining lens position, comparing it with a home position and moving the lens to a new position associated with the particular registration and magnification.

Imaging system with a plurality of document registration positions

A flash exposure optical imaging system is provided which includes a light housing having a movable top and bottom surface. The top surface contains a document platen, the bottom surface a fixed, wide-angle projection lens. These surfaces are vertically translated past a fixed, central housing wall to vary the system conjugate in response to changes in magnification. In a preferred embodiment, a pair of football shaped cams are rotated in response to position signals from a controller initiated by a magnification change. A pair of T-bars and linkage mechanisms are associated with these cams and their motion provides simultaneous vertical motions to the top and bottom housing surfaces, respectively.

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Webster, NY, United States of America

Edward C Bock