Patent EP0925938A2 successfully refreshed from Google Patents.
EP0925938A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Swath density control to improve print quality and extend printhead life in inkjet printers
Assignee: HP Inc
•
Filing: 1998-12-17
•
Granted: —
•
Expires: 2018-12-17
Abstract
Abstract An inkjet printer (10) uses a printhead (12) that passes repeatedly across a print medium in individual swaths. The printhead (12) has individual nozzles (21) that are fired repeatedly during each printhead swath to apply an ink pattern to the print medium. Before any given swath, the printer (10) analyzes factors that might require a reduction in print density. Anticipated printhead temperature is one factor that might require a reduction in print density. The printer (10) monitors the print density and peak printhead temperature during each printhead swath. It then uses these values to calculate, prior to each new swath, a maximum permissible print density. If a reduction in print density is required, the printer (10) temporarily disables selected nozzles (21) to produce a reduced-height swath rather than pausing between swaths or reducing the printhead velocity relative to the page.
Inventors
- 👤 Mark D. Lund
- 👤 Rory A. Heim
- 👤 Steven T. Castle
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 17:06
CPC Classifications
B; B41; B41J; B41J2/00; B41J2/005; B41J2/01; B41J2/015; B41J2/04; B41J2/045; B41J2/04501; B41J2/0458; B41J2/04515; B41J2/04528; B41J2/0454; B41J2/04563; B41J2/485; B41J2/505; B41J2/5056
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
94 words
A method of controlling average printing density over time in an
inkjet printer (10) having a printhead (12) with a plurality of nozzles (21)
arranged in one or more columns to produce full-height print swath across a
print medium, comprising the following steps: passing the printhead (12) repeatedly across a print medium in
individual swaths; firing individual nozzles (21) repeatedly during each printhead swath to
apply an ink pattern to the print medium; using only a subset of the nozzles (21) during a particular swath to
produce a reduced-height swath with reduced print density.
Claim 2
Dependent Claim
39 words
A method as recited in claim 1, wherein the step of using only a
subset of the nozzles is performed in response to a delay in receiving incoming
print data in order to maintain a uniform swath repetition rate.
Claim 3
Dependent Claim
38 words
A method as recited in claim 1, wherein the step of using only a
subset of the nozzles is performed in response to high print densities that are
predicted to raise the printhead temperature to unacceptably high levels.
Claim 4
Dependent Claim
95 words
A method as recited in claim 1, comprising the following
additional steps: monitoring actual swath dot density and peak temperature of the
printhead (12) during each printhead swath; repeatedly calculating a maximum permissible swath dot density in
response to the monitoring step as a function of the actual swath dot density
and peak temperature, wherein the maximum permissible swath dot density
results in a peak printhead temperature that does not exceed a maximum
permissible peak printhead temperature; limiting swath dot density to no greater than the maximum permissible
swath dot density during individual printhead swaths.
Claim 5
Dependent Claim
40 words
A method as recited in claim 1, wherein the step of using only a
subset of the nozzles is performed in response to high print densities that are
predicted to lower ink supplies to the nozzles to unacceptably low levels.
Claim 6
Dependent Claim
69 words
A method as recited in claim 1, wherein the step of using only a
subset of the nozzles is performed in response to any one of the following
conditions: a delay in receiving incoming print data; high print densities that are predicted to raise the printhead temperature
to unacceptably high levels; and high print densities that are predicted to lower ink supplies to the
nozzles to unacceptably low levels.
Claim 7
Independent Claim
118 words
A method of controlling average printing density over time in an
inkjet printer (10) having a printhead (12) with a plurality of nozzles (21)
arranged in one or more columns to produce full-height print swath across a
print medium, comprising the following steps: passing the printhead (12) repeatedly across a print medium in
individual swaths; firing individual nozzles (21) repeatedly during each printhead swath to
apply an ink pattern to the print medium; calculating swath dot density prior to each swath; if the swath dot density of an upcoming swath is greater than a
maximum permissible swath density, using only a subset of the nozzles during
the upcoming swath to produce a reduced-height swath with reduced print
density.
Claim 8
Independent Claim
133 words
A method of controlling printhead temperature in an inkjet
printhead (12) having a plurality of nozzles (21), comprising the following
steps: passing the printhead (12) repeatedly across a print medium in
individual swaths; firing individual nozzles (21) repeatedly during each printhead swath to
apply an ink pattern to the print medium; monitoring actual swath dot density and peak temperature of the
printhead during each printhead swath; repeatedly calculating a maximum permissible swath dot density in
response to the monitoring step as a function of the actual swath dot density
and peak temperature, wherein the maximum permissible swath dot density
results in a peak printhead temperature that does not exceed a maximum
permissible peak printhead temperature; limiting swath dot density to no greater than the maximum permissible
swath dot density during individual printhead swaths.
Claim 9
Dependent Claim
22 words
A method as recited in claim 8, wherein the limiting step
comprises disabling nozzles (21) corresponding to a plurality of pixel rows.
Claim 10
Dependent Claim
57 words
A method as recited in claim 8, wherein the calculating step
comprises multiplying the actual swath dot density of a particular printhead
swath by a factor that is based at least in part on the peak temperature of the
printhead (12) during said particular printhead swath and upon a specified
maximum permissible temperature of the printhead (12).
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.