Redundant nozzle dot matrix printheads and method of use
AssigneeHewlett-Packard Company
InventorDavid E. Hackleman
Life of this patent
Estimating the term…
Abstract
A method and apparatus for ink-jet printing provides a redundancy strategy. A number of drop generators within the printhead is added to the standard array, providing redundant orifices in the nozzle plate at the ends of each column of orifices. In operation, the printhead is shifted regularly or pseudo-randomly such that a different set of nozzles prints adjacent swaths or pixels of a swath in multi-pass or multi-dot per pixel printing.
Claims7
A method of making hard copy using an ink-jet apparatus, having a printhead with a nozzle means, connected to receive ink from an ink supply, for ejecting ink from said printhead onto a print medium, said nozzle means having an orifice plate with at least one column of "n" number of orifices, where "n" is an integer greater than one constituting one orifice in each column for each pixel in a plurality of rows of pixels equal in number to said orifices in said columns to be inked in a swath printed from said printhead, and having "n+m" number of additional orifices in each said column, where "m" is an integer greater than or equal to one, said method comprising:
- a. selecting, between the first orifice of each said column to the n+m.sup.th orifice of each said column, a first contiguous set of "n" orifices;
- b. inking a first swath of rows of pixels on said medium using said first contiguous set of "n" orifices from each said column;
- c. shifting said printhead to select randomly a second contiguous set of "n" orifices between the top orifice of each said column and the n+m.sup.th orifice of each said column;
- and
- d. inking a second swath of rows of pixels using said second set of orifices.
A method of making hard copy using an ink-jet apparatus, having a printhead with a nozzle means, connected to receive ink from an ink supply, for ejecting ink from said printhead onto a print medium, said nozzle means having an orifice plate with at least one column of "n" number of orifices, where "n" is an integer greater than one constituting one orifice in each column for each pixel in a plurality of rows of pixels equal in number to said orifices in said columns to be inked in a swath printed from said printhead, and having "n+m" number of additional orifices in each said column, where "m" is an integer greater than or equal to one, said method comprising the steps of:
- a. selecting, between the first orifice of each said column to the n+m.sup.th orifice of each said column, a first contiguous set of "n" orifices;
- b. entering data representing the locations of said swath to be inked in a memory;
- c. inking according to said data a first swath of rows of pixels on said medium using said first contiguous set of "n" orifices from each said column;
- d. shifting said data representing said first swath of rows of pixels to select a second contiguous set of "n" orifices between the first orifice of each said column and the n+m.sup.th orifice of each said column;
- and
- e. inking said first swath of rows of pixels with said second contiguous set of "n" orifices.
Dependencies are inferred from the claim text.