Thomas D Fields

US Patent:

6565176, May 20, 2003

Filed:

May 25, 2001

Appl. No.:

09/865881

Inventors:

Frank Edward Anderson - Sadieville KY
Thomas Austin Fields - Winchester KY
Paul William Graf - Lexington KY
Yimin Guan - Lexington KY
George Keith Parish - Winchester KY
Kent Lee Ubellacker - Georgetown KY

Assignee:

Lexmark International, Inc. - Lexington KY

International Classification:

B41J 2938

US Classification:

347 14, 347 11

Abstract:

A thermal ink jet printing apparatus maintains stable printing output as certain characteristics of the apparatus change over its operational lifetime. The apparatus includes an ink jet print head with resistive heating elements for receiving electrical energy pulses having a voltage level and for transferring heat energy pulses having a desired energy level into adjacent ink based on the electrical energy pulses. The print head includes nozzles associated with the resistive heating elements through which droplets of the ink are ejected when the heat energy pulses are transferred into the ink. The apparatus further includes a printer controller in electrical communication with the print head. The printer controller determines a pulse count indicative of a number of electrical energy pulses, applies the electrical energy pulses having a first pulse width to the resistive heating elements when the pulse count is less than a threshold value, and applies the electrical energy pulses having an adjusted pulse width to the resistive heating elements when the pulse count exceeds the threshold value. The difference in the first and the adjusted pulse widths compensates for changes in the electrical resistance of the resistive heating elements over time.

US Patent:

6773083, Aug 10, 2004

Filed:

Aug 29, 2001

Appl. No.:

09/942358

Inventors:

Thomas Austin Fields - Winchester KY
William Shannon Spencer - Lexington KY

Assignee:

Lexmark International, Inc. - Lexington KY

International Classification:

B41J 2938

US Classification:

347 5, 358 116

Abstract:

A method of storing usage information in an ink jet printer includes storing low priority usage information in a first memory field. First high priority usage information is stored in a second memory field. Second high priority usage information is stored in a third memory field. The second high priority usage information is substantially identical to the first high priority usage information.

US Patent:

7123282, Oct 17, 2006

Filed:

Jan 14, 2004

Appl. No.:

10/757130

Inventors:

Thomas A. Fields - Winchester KY, US
Craig E. Hadady - Lexington KY, US
Christopher D. Jones - Georgetown KY, US
Philip J. Heink - Lexington KY, US

Assignee:

Lexmark International, Inc. - Lexington KY

International Classification:

B41J 2/47

US Classification:

347240, 347251

Abstract:

A method of minimizing visual artifacts resulting from a laser scan process in an electrophotographic machine, the electrophotographic machine including a photoconductive device having an image forming surface. The method including the steps of obtaining correction data relative to a bowed image and offsetting at least a portion of non-bowed image data dependent upon the correction data, and additionally dependent upon halftone cell growth of a halftone cell.

US Patent:

7205738, Apr 17, 2007

Filed:

Mar 24, 2004

Appl. No.:

10/808101

Inventors:

Danny Keith Chapman - Georgetown KY, US
Thomas Austin Fields - Winchester KY, US
Steven Michael Turney - Lexington KY, US

Assignee:

Lexmark International, Inc. - Lexington KY

International Classification:

H01R 39/46
H02K 13/00
H02P 25/12

US Classification:

318439, 318254, 318138, 318461, 318432, 318434

Abstract:

A motor control circuit uses a stored commutation table to effect time-based commutation of a brushless dc motor. Each entry in the commutation table defines a motor winding commutation state, and an exemplary method of open-loop motor control based on the commutation table comprises commutating the motor based on sequentially selecting table entries at a desired selection rate. That is, motor speed is controlled precisely by controlling the sequential selection rate rather than by relying on feedback from the motor. However, motor feedback for closed-loop control may be used in some modes of operation. For example, the method may include closed-loop control or open-loop control depending on the motor speed range, and may transition from closed-loop to open-loop control.

US Patent:

7206012, Apr 17, 2007

Filed:

Mar 24, 2004

Appl. No.:

10/808043

Inventors:

William P. Cook - Lexington KY, US
Thomas A. Fields - Winchester KY, US
Allen P. Johnson - Lexington KY, US
Christopher D. Jones - Georgetown KY, US
Gregory L. Ream - Lexington KY, US

Assignee:

Lexmark International, Inc. - Lexington KY

International Classification:

B41J 2/47
B41J 2/435

US Classification:

347234, 347245

Abstract:

An optical scanner is provided having a memory device thereon. The memory device may store operational characteristics of the optical scanner or data that characterizes laser beam scan path and/or laser power requirements by each laser of the optical scanner. The memory device may be used to store historical information such as device temperature, cycles of operation and other historical information of components within a corresponding electrophotographic device. Still further, the electrophotographic device to which the optical scanner is installed may write operational data to the memory device, for example, to store a backup of registration and other operational parameters that are typically stored by the controller of the electrophotographic device.

US Patent:

7349123, Mar 25, 2008

Filed:

Mar 24, 2004

Appl. No.:

10/807870

Inventors:

Cyrus B. Clarke - Lexington KY, US
Thomas A. Fields - Winchester KY, US
Allen P. Johnson - Lexington KY, US
Christopher D. Jones - Georgetown KY, US

Assignee:

Lexmark International, Inc. - Lexington KY

International Classification:

H04N 1/40

US Classification:

358 19, 358504

Abstract:

Systems and methods are provided for characterizing laser beam process direction position errors in an electrophotographic device. Once the process direction position errors of a given beam laser beam system have been characterized, an image is adjusted or warped prior to being processed by the laser beam system to compensate for laser beam process direction position errors, e. g. , bow and skew.

US Patent:

7375738, May 20, 2008

Filed:

Mar 24, 2004

Appl. No.:

10/808155

Inventors:

William P. Corbett - Lexington KY, US
Thomas A. Fields - Winchester KY, US
Allen P. Johnson - Lexington KY, US
Christopoher D. Jones - Georgetown KY, US

Assignee:

Lexmark International, Inc. - Lexington KY

International Classification:

B41J 2/435
B41J 2/47

US Classification:

347234, 347248

Abstract:

Systems and methods are provided for electronically adjusting an image to compensate for laser beam process direction position errors in an electrophotographic device. Initially, a bow profile is defined that characterizes the process direction position errors of a laser beam across a scan line. The device subsequently reads an image to be printed from a first memory location, performs pixel shifts on select columns thereof based upon the bow profile, and temporarily stores the adjusted image data to a second location of memory. The adjusted image data is then communicated to a printhead of the device.

US Patent:

7403214, Jul 22, 2008

Filed:

Feb 21, 2006

Appl. No.:

11/358351

Inventors:

Thomas A. Fields - Winchester KY, US
Christopher D. Jones - Georgetown KY, US
William P. Cook - Lexington KY, US
Cyrus B. Clarke - Lexington KY, US
Jonathan C. Frey - Lexington KY, US

Assignee:

Lexmark International, Inc. - Lexington KY

International Classification:

B41J 2/435

US Classification:

347236, 347246

Abstract:

The dynamic range of an electrophotographic device may be shifted by calibrating a laser power of a laser source to operate within a first range of power levels during a laser power adjustment operation. At least one laser control parameter is modified after calibrating the laser power so that the laser source is operable within a second range of power levels different from the first range of power levels and a beam emitted by the laser source is controlled within the second range of power levels when the beam is directed towards an image area of a photoconductive surface.