Hewlett-packard Company

Lowell J Stewart

Robert D Haselby

Daniel Steven Kline

Michael A Nguyen

Chuong C Ta

Robert A Boeller

Steven Ray Card

Irene H Williams

Edward D Davis

Curt Behrend

Samuel R Haugh

Alfred H Mebane Iv

Greater throughput is possible by using wider print swaths in each traverse across printing media. Multiple print cartridges are mounted to be offset from each other in the media scan direction (X-axis). The amount of offset is adjustably varied by selective on/off control of individual printing elements as well as by relative mechanical movement of the print cartridges.

Wide-swath printer/plotter using multiple printheads

A process for start up of a thermal ink-jet printhead cartridge that includes a sequence of nozzle clearing procedures of increasing severity which are performed in sequence so long as some of the nozzles of the printhead fail to fire ink drops pursuant to ink firing pulses provided to the printhead or until all of the procedures have been performed.

Pen start up algorithm for black and color thermal ink-jet pens

An optical drop detect circuit for a thermal ink jet printer. The optical drop detect circuit includes an optical sensor for providing an electrical output indicative of a presence of an ink drop, a transconductance amplifier responsive to the output of said optical sensor, first and second cascaded bandpass amplifiers responsive to the transconductance amplifier, a first comparator circuit responsive to the output of the cascaded bandpass amplifiers for providing an output pursuant to optical sensing of a first minimum ink drop size, and a second comparator circuit responsive to the output of the cascaded bandpass amplifiers for providing an output pursuant to optical sensing of a second minimum ink drop size.

Drop size detect circuit

A hybrid sample rate servo motor employing rate feedback compensation is disclosed. The system employs a shaft encoder having a predetermined resolution to provide position data which are pulses indicating the shaft has moved another resolution unit. Under high motor velocity conditions the rate compensation feedback loop is operated at a conventional constant sample rate. Under low velocity conditions, the sample rate at which the rate compensation feedback loop is operated is modified so that rate samples are taken and calculated only when new position data are available from the motor encoder. Rate quantization error is substantially reduced, thereby leading to more robust controller operation.

Hybrid sample rate servo motor controller

A pen-lift system is provided which can achieve high speed plotting while maintaining line definition of drafting quality. The system includes a pen-lift mechanism for raising and lowering the pen, a pressure control system in order to provide a constant pen force for different kinds of pens, a velocity controller for varying the vertical velocity of the pen in response to changes in platen height and relative lateral pen position, and a position controller for sensing the present pen height relative to the platen and for actuating the pen-lift mechanism to achieve the desired pen-lift heights for different plotting situations.

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Poway, CA, United States of America

Lowell J Stewart