Xerox Corporation

Other

Tibor S Fisli

Thomas L Paoli

Patrick Yasuo Maeda

Raj B Apte

Gregory J Kovacs

James J Appel

Charles J Kramer

Jean-Michel Guerin

David A Grafton

Alan F McCarroll

Donald J Quant

R Donald Yingling, Jr Deceased

A color printer uses multiple linear arrays of surface emitting lasers of differing wavelengths and polarization states to simultaneously expose widely separated positions on the same or different photoreceptors. Each array is imaged by the same optical system to the photoreceptor. The multiple linear arrays can be closely spaced in a monolithic structure.

Color xerographic printer with multiple linear arrays of surface

In a raster output scanner (ROS) of a xerographic printing device, the location of an apparent source of the light beam is adjusted within a light emitting apparatus to enable spot position control anywhere along a scanline to insure subline registration of an image. This is accomplished by placing the apparent source location of the light emitting apparatus on a movable plate. The apparent source is located at the position from which a light beam is emitted from an output end of a laser source or waveguide connected to the laser source. The movable plate is adjusted by actuators which may be comb drives, thermal bimorphs or piezoelectric drive mechanisms.

Micropositioned laser source for raster output scanners

The optical path length of a raster output scanning (ROS) system is minimized by the use of a laser beam source for emitting a light beam with an enlarged divergence ratio. A super-elliptic light source beam with at least an 8:1 elliptic ratio of the major cross-scan axis to the minor scan axis will minimize the optical path length of a raster output scanning (ROS) system. The large divergence ratio of the super-elliptic light beam reduces the required focal lengths in the ROS optics while maintaining the desired numerical apertures and high energy throughput.

Raster output scanning system with a super-elliptic laser beam source

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.

Method and apparatus for multi-channel printing in a raster output

A raster scanning optical system and method for adjusting a scan line location on a light receiving member by a desired amount. A photoreceptor receives a light beam as the photoreceptor is advancing in a slow scan direction. A polygon mirror scans the light beam across the photoreceptor at a scan line location extending in a fast scan direction. A light transmissive plate is located in the path of the light beam between the polygon mirror and the photoreceptor. The light transmissive plate is adjusted by an adjusting device to displace the scan line location on the photoreceptor by the desired amount in a direction parallel to the slow scan direction.

Raster scanning optical system and method for adjusting scan line

A raster scanning optical system and method emits a first light beam and a second light beam onto a light receiving member. A scanning device has at least one facet for reflecting the first and the second light beams to the light receiving member. A light transmissive plate is located in a path of the first light beam between the first light emitting device and the scanning device. The light transmissive plate adjusts the sagittal direction and the tangential direction of the first light beam by a desired amount so that the first and second light beams are reflected from positions of the scanning device that are closer to each other and parallel in both the sagittal and tangential meridian.

Method and apparatus for adjusting orientation of light beams in a

A raster scanning optical system and method for adjusting the pixel placement of light beams being scanned across an image receiving device. A spot velocity of a first laser beam is measured and then a spot velocity of a second laser beam is measured. From these measurements, the pixel positions of each of the beams can be determined. The firing rate of the second laser beam is then adjusted to adjust the pixel placement of the second beam. This helps avoid problems caused by tangentially offset laser diodes that scan with varying spot linearities.

Method and apparatus for adjusting the pixel placement in a raster

A nonmonolithic, multiple wavelength laser array having closely spaced lasing elements which are accurately spaced both in a plane perpendicular to the optical axes of the laser beams and along the optical axes. The laser array includes a plurality of lasing elements mounted on a high thermal conductivity spacer. The spacer has a front surface angled relative to the optical axes of the lasing elements, and parallel mounting surfaces. The mounting surfaces and front surfaces join to form front edges. The laser elements mount such that the front facet of each lasing element is aligned with an associated front edge. Beneficially, either the spacer is electrically conductive, or the spacer is coated with a layer of conductive material. The laser array can be used in a printer to offset the laser elements to correct for the wavelength dependency of the printer's optical system.

Offset mounting of nonmonolithic multiwavelength lasers

In a raster scanning system (ROS) of a multi-station xerographic printing device, the image height of each of the images formed from a plurality of clustered laser beams having dissimilar wavelengths is changed so that the image heights approximate each other. This is accomplished by passing one or more of the light beams through light transmissive plates having a predetermined thickness and index of refraction. The light transmissive plates can be optical filters that also one used to separate the clustered light beams based upon their wavelength and/or polarization.

Method and apparatus for reducing differences in image heights of images

The present invention is a novel raster output scanner (ROS) configuration that employs modulated laser diodes as the light source. Each laser diode is coupled to a dedicated driver that modulates the light beam according to digital video signal data. The present invention employs a single-channel acoustic-optic cell that deflects the multiple beams to maintain proper facet tracking. A single transducer is coupled to the single-channel acoustic-optic cell that generates the necessary acoustic wave to maintain proper tracking.

High efficiency multispot facet tracked raster output scanning system

A raster scanning system has an image receiving device that receives a light beam, a scanning device for scanning the light beam across the image receiving device and a mirror located in the path of the light beam between the scanning device and the image receiving device for directing the light beam to the image receiving device. An adjusting device adjusts a curvature of the mirror to correct for bow of the light beam on the image receiving device.

Method and apparatus for adjusting the curvature of a folding mirror in

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.

Multiple beam raster output scanner optical system having telecentric

The present invention is a thin film coating that may be applied to various optical elements and a method for controlling the size of the imaging spot from multiwavelength sources in an optical path. A selective optical element made in accordance with the principles of the present invention comprises an optical surface. Upon the surface, thin film coatings are deposited that define zones of transmission, each zone transmits a desired wavelength band. Beyond this zone, the surface is effectively opaque to a specified wavelength band. The zones for each wavelength are individually calculated to give an effective aperture for each wavelength such that the spot size for all wavelengths meet user specifications.

Selective optical elements for multiwavelength electronic print heads

An imaging device and method for projecting imaged light according to print data onto an imaging medium includes a light source, an optics system receiving light from the light source, and at least one modulator having a plurality of individually addressable reflective elements. The optics system images or focuses the light source onto the at least one modulator and the at least one modulator selectively modulates a portion of the light onto the imaging medium according to the print data. The optic system includes a condenser lens positioned between the light source and the at least one modulator and an imaging lens be positioned between the at least one modulator and the imaging medium. A numerical aperture of the condenser lens is set to be equal to a numerical aperture of the imaging lens to critically illuminate the modulator. The light source may include a plurality of light emitting elements. Light beams from the plurality of light emitting elements are overlapped on the reflective elements at the full width half max point of the light beams to uniformly illuminate the reflective elements.

Method and apparatus for preparing imaged light

The present invention is a scanning system and a novel method for compensating for the variations in the output power of the beam from an A-O cell. The novel method involves varying the amount of drive current through the laser diode in such a fashion as to compensate for the loss of power due to diffraction inefficiencies. The amount of driving current is dependent upon the amount of power desired in the output beam from the A-O cell. The system and method of the present invention sets the output power from the A-O cell to a desired value. As the diffraction efficiency increases at other portions of the scan, the drive current is cut appropriately to compensate for the increased efficiency; thus keeping the output spot power at the desired value. Likewise, as the diffraction efficiency decreases at other portions of the scan, the drive current should be increased to compensate for the decrease in efficiency; thereby maintaining the desired value.

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Los Altos Hills, CA, United States of America

Tibor S Fisli