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EP0863012A1 Expired / Lapsed EP ⏱️ 0.0 years remaining

Detection of printhead nozzle functionality by optical scanning of a test pattern

Assignee: HP Inc
•
Filing: 1998-03-03
•
Granted: —
•
Expires: 2018-03-03
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Abstract

Abstract A nozzle detection test pattern has been developed which can be sensed by an optical sensor 1ocated on an inkjet printer carriage. By having the same nozzle print ink drops on multiple pixels to form a single thickened test line during multiple passes of the printhead, it is possible to thereafter scan across such test line and automatically determine by the light contrast ratios which nozzles are not firing properly. A green light LED is uded to illuminate the magenta, cyan and black test patterns as they are being sensed, and a blue light LED is used to illuminate the yellow test pattern as it is being sensed. A separate test pattern is used for each printhead ink color. The test pattern constitutes six rows with forty test lines on each row for a printhead having 240 active nozzles.

Inventors

  • 👤 Chris T. Armijo
  • 👤 Gonzalo Gaston
  • 👤 Javier Lagares
  • 👤 Antoni Gil

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-09 17:56
CPC Classifications
B; B41; B41J; B41J2/00; B41J2/005; B41J2/01; B41J2/135; B41J2/165; B41J2/16579; B41J2/015; B41J2/04; B41J2/045; B41J2/04501; B41J2/0451; B41J2/0458; B41J29/00; B41J29/38; B41J29/393; B41J2029/3935

Claims Analysis

Total Claims: 5
Claim 1
Independent Claim 66 words
Apparatus for detecting nozzle functionality in an inkjet printer, comprising: a scanning carriage with at least one printhead; an optical sensor capable of detecting the presence or absence of ink drops on media; a source of illumination; a test pattern having ink drops from a single nozzle forming a test group; and means for moving the optical sensor across said test group to detect non-firing nozzles.
Claim 2
Dependent Claim 15 words
The apparatus of claim 1 wherein said optical sensor is mounted on said scanning carriage.
Claim 3
Dependent Claim 16 words
The apparatus of claim 1 wherein said source of illumination is mounted on said scanning carriage.
Claim 4
Dependent Claim 18 words
The apparatus of claim 1 wherein said source of illumination includes at least two different colored light sources.
Claim 5
Independent Claim 91 words
A method of determining nozzle functionality in an inkjet printer having a plurality of different nozzle groups, each group firing a different color ink, comprising the steps of: printing a test pattern from the different nozzle groups, with predetermined portions of the test pattern being printed by different nozzles, respectively; shielding the test pattern from ambient light; illuminating the test pattern with artificial light; optically scanning across the portions of the test pattern during said shielding and illuminating steps to sense which portions have been printed satisfactorily by a particular nozzle.

References Cited (Backward Citations)

DE3246707A1 Cited
EP0348234A2 Cited
JPH03104678A Cited
JPH04169239A Cited
EP0500281A2 Cited
JPH0624008A Cited
EP0622220A2 Cited

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