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EP0622220A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Multiple inkjet cartridge alignment for bidirectional printing by scanning a reference pattern

Assignee: HP Inc
•
Filing: 1994-04-21
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Granted: —
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Expires: 2014-04-21
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Abstract

Abstract A system for correcting for a time of flight delay of a drop of ink from an inkjet printhead includes a first mechanism (152) for scanning the printhead (102) along a first axis at a first velocity. A control circuit (300), responsive to inkjet timing signals, causes the printhead (102) to eject ink onto a media (30) to create a test pattern (40) thereon as the printhead (102) is scanned along the first axis. A sensor (200) optically senses the test pattern (40) and provides a time of flight dependent phase signal in response thereto. This signal is processed to provide time of flight delay corrected inkjet timing signals for the first velocity in response to the phase signal. In a particular implementation, the processor (170) is adapted to add an additional delay to the corrected timing signals to correct for curvature. <IMAGE>

Inventors

  • 👤 Robert W. Beauchamp
  • 👤 Paul R. Sorenson
  • 👤 Keith E. Cobbs

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-09 15:30
CPC Classifications
B; B41; B41J; B41J2/00; B41J2/005; B41J2/01; B41J2/015; B41J2/04; B41J2/045; B41J2/04501; B41J2/04505; B41J11/00; B41J11/36; B41J11/42; B41J11/46; B41J2/04586; B41J2/07; B41J19/00; B41J19/14; B41J19/142

Claims Analysis

Total Claims: 8
Claim 1
Independent Claim 124 words
A system for correcting for a time of flight delay of a drop of ink from an inkjet printhead (102) characterized by: A first mechanism (152) for scanning the printhead (102, 104, 106, 108) along a first axis at a first velocity; A control circuit (300) responsive to inkjet timing signals for causing the printhead to eject ink onto a media (30) to create a test pattern (40) thereon as the printhead is scanned along the first axis; A sensor (210) for optically sensing the test pattern (40) and providing a time of flight dependent phase signal in response thereto; and A processor (170) for providing time of flight delay corrected inkjet timing signals for the first velocity in response to the phase signal.
Claim 2
Dependent Claim 18 words
The invention of Claim 1 wherein the test pattern (40) includes a plurality of horizontally spaced vertical bars.
Claim 3
Dependent Claim 21 words
The invention of Claim 2 wherein the sensor (30) includes a phase plate (230) in optical alignment with a photodetector (240).
Claim 4
Dependent Claim 17 words
The invention of Claim 3 wherein the phase plate (230) includes a plurality of apertures horizontally spaced.
Claim 5
Dependent Claim 18 words
The invention of Claim 4 wherein spacing of the apertures is equal to the spacing of the bars.
Claim 6
Dependent Claim 30 words
The invention of Claim 5 wherein the processor (170) is programmed to determine the frequency of the signal detected by the photodetector (240) and provides a signal in response thereto.
Claim 7
Dependent Claim 40 words
The invention of Claim 6 wherein the processor (170) is programmed to compare the frequency of the detected signal to a spatial frequency of the test pattern (40) and provide the flight delay corrected inkjet timing signals in response thereto.
Claim 8
Dependent Claim 22 words
The invention of Claim 1 wherein the processor (170) adds an additional delay to the corrected timing signals to correct for curvature.

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