Lexmark International, Inc.

Thomas Austin Fields

Christopher Dane Jones

Cyrus Bradford Clarke

Allen P Johnson

William Paul Cook

Danny Keith Chapman

Steven Michael Turney

William P Corbett

Frank Edward Anderson

George Keith Parish

Yimin Guan

Gregory Lawrence Ream

Philip Jerome Heink

Kent Lee Ubellacker

David Brian Langer

Steven Wayne Parish

Paul W Graf

Brian Anthony Reichert

Craig Eric Hadady

William Shannon Spencer

Jonathan Carey Frey

Christopoher D Jones

Laser beam scan line nonlinearity is compensated for by providing algorithms for generating linearity profiles which are used by a corresponding registration system in an electrophotographic device to determine the placement of Pels across a scan line.

Systems for performing laser beam linearity correction and algorithms and methods for generating linearity correction tables from data stored in an optical scanner

Correction of rotary encoder eccentricity in an image forming device having a motor controller using period and position pulse train feedback signals. A motor includes an encoder disc rotating with the motor and at least two encoder sensors disposed at different circumferential positions about the encoder disc. A controller may use a high speed clock to calculate a corrected speed count based on speed counts determined from the number of clock cycles that elapse per cycle of pulse trains from the encoders. The controller may also calculate a corrected position count based at least partly on one or more position counts determined from the number of clock cycles that elapse between periodic sampling points and transitions of encoder pulse trains. The corrected position count may also be calculated based on a position count and one or more speed counts.

Encoder eccentricity correction for motion control systems

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.

Systems and methods for adjusting the dynamic range of a scanning laser beam

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.

Electronic systems and methods for reducing laser beam process direction position errors

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.

Algorithms and methods for determining laser beam process direction position errors from data stored on a printhead

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.

Memory device on optical scanner and apparatus and method for storing characterizing information on the memory device

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.

Method and apparatus for time-based dc motor commutation

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.

Method and apparatus for minimizing visual artifacts in images generated by an electrophotographic machine

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.

Method and apparatus for non-volatile memory usage in an ink jet printer

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.

Long-life stable-jetting thermal ink jet printer

A print system includes a printer having a printer controller. One or more optional support devices are associated with the printer, wherein each optional support device includes a device controller. The system further includes a bi-directional serial communications path, including one or more trunklines, which provides serial electrical interconnection between the printer controller and each device controller of each optional support device of the system. The printer controller automatically assigns a unique device address to each optional support device. Transmission error detection system and method are provided at the printer controller and/or each optional support device.

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Winchester, KY, United States of America

Thomas Austin Fields