Method and apparatus for improving print quality on failure of a thermal ink jet nozzle
AssigneeHewlett-Packard Company
InventorPaul J. McClellan
Life of this patent
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Abstract
When a print nozzle or other firing element of an ink jet print head fails, printed image quality suffers. In a print head where there are additional printing elements that continue to work and that are adjacent the failed element, a failed firing element can be compensated for by increasing the firing rate of, or firing pulse duration to, one or more printing elements that are adjacent to the failed element. Additional ink deposited on the printing medium will bleed onto areas that are normally printed onto by the failed firing element.
Claims19
In a printer print head having a plurality of printing elements, each printing element being capable of depositing ink drops on a print medium in response to electrical firing pulses applied to said printing elements so as to produce an image thereon, a method of improving printed image quality in response to a failed printing element comprised of the steps of:
- energizing at least a first printing element by an increased amount;
- whereby at least some of the ink deposited on said printing medium by said first printing element migrates onto the area of said printing medium whereat said failed printing element would normally deposit ink.
In a printer print head having a plurality of printing elements, each printing element being capable of depositing ink drops on a print medium in response to electrical firing pulses applied to said printing elements so as to produce an image thereon, a method of improving printed image quality in response to a failed printing element comprised of the steps of:
- a. energizing a first printing element by an increased amount;
- b. energizing a second printing element by an increased amount;
- whereby at least some of the ink deposited on said printing medium by said first and second printing elements migrates onto the area of said printing medium whereat said failed printing element would normally deposit ink.
In a printer print head having a substantially linear array of printing elements, each element depositing ink drops on a printing medium in response to electrical firing pulses applied to said printing elements to produce an image thereon, a method of improving printed image quality in response to a failed printing element comprised of the steps of:
- a. energizing a first printing element adjacent to said failed element on a first side of said failed element by an increased amount;
- b. energizing a second printing element adjacent to said failed element on a second side of said failed element by an increased amount;
- whereby at least some of the ink deposited on said printing medium by said first and second printing elements migrates onto the area of said printing medium whereat said failed printing element would normally deposit ink.
A printer providing an improved image quality in response to a failed first printing element in a print head, said printer comprised of:
- a. a plurality of printing elements, each printing element being capable of depositing ink drops on a print medium in response to electrical firing pulses applied to said printing elements from a controller so as to produce an image on said print medium;
- b. a controller, energizing a second predetermined printing element of said plurality of printing elements, by an increased amount upon the failure of said first printing element;
- c. a controller energizing a third predetermined printing element of said plurality of printing elements by an increased amount upon the failure of said first printing element;
- d. an ink reservoir, operatively coupled to said plurality of printing elements and providing ink thereto;
- whereby at least some of the ink deposited on said printing medium by said second and third printing elements migrates onto the area of said printing medium where at said failed printing element would normally deposit ink.
A print head capable of producing improved-quality print images upon the failure of a printing element, said print head comprised of:
- a. a substrate defining an ink aperture through which ink flows from a reservoir, said substrate further having first, second and third ink energizing elements, each of said ink energizing elements being configured and operative to deposit ink onto print media;
- b. an ink reservoir, operatively coupled to said first and second printing elements by which ink flows to said ink energizing elements, for placement onto a printing medium;
- c. means for firing said first and second ink energizing elements at an increased rate upon the failure of said third ink energizing element.
Dependencies are inferred from the claim text.