ROBERT PAUL KOWALSKI
Pilots at Valerie Ct, Campbell, CA

5138340, Aug 11, 1992

Dec 6, 1990

7/624117

Robert A. Sprague - Saratoga CA
Mark S. Bernstein - Belmont CA
Robert P. Kowalski - Campbell CA
David L. Hecht - Palo Alto CA
David L. Steinmetz - Mountain View CA
David E. Kizer - San Jose CA
Robert L. Thornton - East Palo Alto CA

Xerox Corporation - Rochester NY

G01D 1514

346108

A technique for producing pixel patterns at different selected wavelengths. A diode laser is repeatedly pulsed and has its temperature changed from pulse to pulse, which causes the output wavelength to change. This allows pixel patterns to be interlaced by the use of dispersive elements such as prisms in the optical train. A temperature shift of about 15. degree. C. provides a wavelength shift of about 30 angstroms, which is usable. A temperature shift of 20. degree. C. -30. degree. C. or more is preferable. The temperature shifts may be accomplished by supplying specific currents below threshold and above threshold. For two-wavelength operation, the laser is driven at a first bias current below threshold for a first non-illumination interval, at a first pulse current above threshold for a first illumination interval, at a second bias current below threshold for a second non-illumination interval, and a second pulse current above threshold for a second illumination interval. The bias currents are sufficiently different so as to establish different operating temperatures for the illumination intervals. The temperature shifts may also be accomplished at least in part by use of an auxiliary heater.

6494565, Dec 17, 2002

Nov 5, 1999

09/434981

Richard N. Ellson - Palo Alto CA
Robert P. Kowalski - Campbell CA
Babur Hadimioglu - Mountainview CA
Thanh Duc Truong - Walnut CA

Xerox Corporation - Stamford CT

B41J 2135

347 46

An active controller is provided to control operation of an acoustic printhead in which impedance of the printhead changes with both the active printing row and the distribution of active ejectors in the row. The active controller varies the input power to the printhead in response to active ejectors. Power requirements are insured while also reducing power consumption and maintaining print quality. The determination of RF power is based on the active row, how many ink ejectors are to be switched on, and their position within a row. Look-up tables used to determine proper attenuation or power values are provided in a cascaded fashion.

5081597, Jan 14, 1992

Dec 21, 1989

7/454349

Robert P. Kowalski - Campbell CA

Xerox Corporation - Stamford CT

G06F 1520

364525

In accordance with the present invention, correction factors for dynamically equalizing the optical channels of a multichannel optical imaging system, individually or on a group-by-group basis, are recursively computed while the imaging system is idle (i. e. , not printing) through the use of an iterative process comprising the steps of: measuring the output intensities of the respective sets of channels, sequentially comparing the measured channel intensities against a system calibrated reference intensity level, and adjusting the correction factor for each set of channels that is found to be operating at an intensity level deviating from the reference intensity level in the direction that is required to reduce the magnitude of the deviation (unless the correction factor value already is at the limit of its dynamic range in that direction). Preferably, the correction factor adjustments are made by incrementing and decrementing their least significant values, thereby maximizing the sensitivity of each iteration of the process to the affect of the immediately preceding iteration on the amount of crosstalk occurring between neighboring sets of channels. For example, the correction factors suitably are multi-bit binary values which are adjusted by incrementing and decrementing their least significant bits (LSB's).

5828469, Oct 27, 1998

Mar 21, 1997

8/822446

Robert P. Kowalski - Campbell CA
Carol A. Hankins - Palo Alto CA

Xerox Corporation - Stamford CT

H04N 104

358498

A substantially vertical contact scanning assembly records both sides of a document in a memory. In one embodiment, the vertical contact imaging assembly is a pair of two-dimensional sensor arrays. The document is fed between the pair of two-dimensional sensor arrays when they are space apart from each other using gravity. A registration stop positioned under the vertical contact imaging assembly aligns one edge of the document with an edge of the pair of two-dimensional sensor arrays. Once properly registered, the pair of two-dimensional sensor arrays are brought into contact with the document. After recording an electronic representation of both sides of the document, the two-dimensional sensor arrays are spaced apart from each other. Subsequently, the document is released into an output tray using gravity by lowering one edge of the registration stop.

5640252, Jun 17, 1997

Dec 12, 1995

8/570880

William D. Turner - San Marino CA
Robert P. Kowalski - Campbell CA
Sven E. Karlsson - San Jose CA

Xerox Corporation - Stamford CT

H01L 2714

358497

An apparatus for imaging books or other bound documents with minimal stress being applied to the book structure, and for successively imaging and turning pages of a book without the need for manual intervention. The book imager includes a support, for placement of a book in an open position, an imager having opposed imaging surfaces capable of simultaneously imaging the entire exposed, facing adjacent pages of the book in a distortion preventing manner, and a page turner. The support and the imager are relatively movable toward and away from one another, from a first position in which imaging is effected, to a second position in which page turning is effected.

5193122, Mar 9, 1993

Dec 3, 1990

7/621478

Robert P. Kowalski - Campbell CA
Dan S. Bloomberg - Palo Alto CA

Xerox Corporation - Rochester NY

G06K 934

382 9

A simple technique for determining and indicating, in real times as an image is scanned, the presence of halftones within a page. in brief, the technique contemplates monitoring a pixel stream, typically on a line basis, determining the proportion of pixel transitions (relative to the overall number of pixel intervals), and controlling the process based on this information. In one embodiment, a numerical value representing such a proportion is compared to a threshold, and a value in excess of the threshold is taken to signify the presence of halftone regions. Based on this, special processing for halftones is enabled or special processing for non-halftone regions is disabled. In a specific hardware embodiment, the pixel monitoring circuitry includes a transition detector (50), an up/down activity counter (52), a threshold selector (55), and a counter controller (57).

7116613, Oct 3, 2006

May 22, 2003

10/443184

David L. Hecht - Palo Alto CA, US
Uma Srinivasan - Mountain View CA, US
Robert Matusiak - Sunnyvale CA, US
Robert P. Kowalski - Campbell CA, US
Eric J. Shrader - Belmont CA, US

Palo Alto Research Center Incorporated - Palo Alto CA

G11B 5/09

369 4437, 369 4429, 369 4435, 369 5328

A beam position control system controls a position of a beam directed from a beam source. The beam position control system includes a beam position sensing system that generates one or more satellite beams which are used to determine the position of a main beam. A beam offset computation block determines a relative position of the main beam with respect to a desired main beam position and provides beam offset information to a controller that generates a compensation signal used to adjust the main beam position to the desired main beam position via a beam actuation system.