Browse Prior Art Database

FAILED JET COMPENSATION IN A COLOR THERMAL INK JET PRINTHEAD

IP.com Disclosure Number: IPCOM000027479D
Original Publication Date: 1997-Apr-30
Included in the Prior Art Database: 2004-Apr-08
Document File: 2 page(s) / 62K

Publishing Venue

Xerox Disclosure Journal

Abstract

A full-width, full-color thermal mk jet print bar assembly comprised of four (4) full-width arrays; a black and the remaining colors (cyan, magenta, and yellow). A defective nozzle or jet, caused by a failure in the associated heater printer in any of the printheads, creates white streaks on the output prints.

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XEROX DISCLOSURE JOURNAL

FAILED JET COMPENSATION IN A COLOR THERMAL INK JET PRINTHEAD
Kurt L. Jacobs

Proposed Classification
U. S. C1.347/087 Int. C1. B41j 02/175

A full-width, full-color thermal mk jet print bar assembly comprised of four (4) full-width arrays; a black and the remaining colors (cyan, magenta, and yellow). A defective nozzle or jet, caused by a failure in the associated heater printer in any of the printheads, creates white streaks on the output prints.

Typically, the print bar most likely to experience a jet failure is the black bar since this is the one used with the most frequency. By replacing the missing black information created by the failed jet with process black, the objectionable white streaking in output prhts can be eliminated.

A failed jet in the associated heater can be identifed by current sensing techniques. An

output signal, representing the location of the failed jet, is sent to memory circuits in the Electronic Sub System. This signal is converted into information to create a process black output at the failed jet pixel location using jets from the color print bars. Due to the fact that bad jets are typically random dispersed over the print bar, an area no larger than 11600 inch (depending of spots per inch) would be left vacant by a missing jet. By replacing this spot with near black, the human eye integrates the near black with the neighboring true black and renders an output print that is acceptable to the customer.

DPS546

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