Back to results
US 6,310,640 B1Granted
Banding reduction in multipass printmodes
AssigneeHewlett-Packard Company
InventorRonald A Askeland
Life of this patent
Estimating the term…
Abstract
A swath printer and multipass printing method for improving print quality. The printer minimizes dot placement errors on a printed medium due to depositing drops of ink from lower quality printhead nozzles by providing a printmask having a mask pattern which enables those nozzles most susceptible to dot placement error to print relatively fewer times, and which enables other nozzles less susceptible to dot placement error to print relatively more times. Such a printer and method does not require the use of fractional print modes having a corresponding reduction in throughput.
Claims21
A swath printing system, composing:
- a frame;
- a carriage attached to the frame for relative motion with respect to a print medium;
- a printhead mounted in the carriage, the printhead including a single-color ink and having nozzles through which the ink is ejected onto a pixel grid of multiple rows when the carriage makes a printing pass over the print medium;
- a print controller operatively connected to the printhead for controllably activating the nozzles to deposit the single-color ink onto the print medium;
- and
- a printmask operatively coupled to the print controller to define groups of the nozzles to be activated during multiple printing passes of the printhead over the print medium, the printmask having
- a first mask pattern associated with an individual printing pass to decrease the total number of possible times one nozzle group can be activated to deposit the single-color ink on certain ones of the rows printed in the individual printing pass, and
- a second mask pattern associated with a different printing pass to increase the total number of possible times an other nozzle group can be activated to deposit the single-color ink on the same certain ones of the rows printed in the different printing pass,
- wherein the decrease and the increase are relative to a substantially equal number of possible times for all nozzle groups.
6 more elements
A multipass swath printer, comprising:
- a frame;
- a carriage attached to the frame for relative motion with respect to a print medium having a pixel grid of multiple rows, each of the rows having a plurality of pixel locations;
- a printhead mounted in the carriage, the printhead having nozzles through which drops of a single-color ink are deposited onto the print medium, each nozzle capable of depositing drops of the single-color ink onto a corresponding one of the rows when the carriage makes a printing pass over the print medium;
- a print controller operatively connected to the printhead for controllably activating the nozzles to deposit the drops of the ink;
- and
- a printmask operatively coupled to the print controller to govern the ejection of drops of the single-color ink during multiple printing passes of the carriage over the print medium, the printmask having a mask pattern allowing some of the nozzles to deposit the drops of the single-color ink in fewer than an average number of possible pixel locations of the corresponding ones of the rows in each printing pass, and allowing others of the nozzles to deposit the drops of the single-color ink in more than an average number of possible pixel locations of the corresponding ones of the rows in each printing pass.
3 more elements
A method for printing with an inkjet printer on a print medium, comprising:
- providing a printhead having a single-color ink and nozzles for depositing the ink onto the print medium during a printing pass, each nozzle having a print quality;
- providing a printmask to govern the total number of possible times nozzles can be activated during the printing pass;
- decreasing relative to an average number of times for all nozzles the total number of possible times certain lower print quality nozzles can be activated during the printing pass;
- and
- increasing relative to an average number of times for all nozzles the total number of possible times certain higher print quality nozzles can be activated during the printing pass.
2 more elements
A method for printing with an inkjet printer on a print medium having rows of possible pixel locations, comprising:
- providing a printhead having a single-color ink, and nozzles for depositing the ink onto the possible pixel locations in a row, each nozzle having a print quality;
- moving the printhead and the print medium relative to each other during a plurality of printing passes;
- providing a printmask to govern depositing the single-color ink in each of the possible pixel locations of each row for each of the nozzles during all printing passes;
- and
- as governed by the printmask during each printing pass, depositing the ink in fewer possible pixel locations in rows printed with nozzles of lower print quality, and in more possible pixel locations in rows printed with nozzles of higher print quality,
- wherein the fewer possible pixel locations and the more possible pixel locations are relative to depositing the ink in an equal number of possible pixel locations with all nozzles.
3 more elements
Dependencies are inferred from the claim text.