Method and apparatus for voltage correction
AssigneePolaroid Corporation
InventorsDaniel P. Bybell, Jay E. Thornton
Life of this patent
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Abstract
A method is provided for providing the same amount of energy to each print head element in a thermal printer during each print head cycle used to print an image, regardless of the number of print head elements that are active during each print head cycle. The desired amount of energy may be provided to a plurality of print head elements that are active during a print head cycle by delivering power to the plurality of print head elements for a period of time whose duration is based in part on the number of active print head elements. The period of time may be a portion of the print head cycle.
Claims15
In a thermal printer comprising a plurality of print head elements, a method for printing at least a first line of a digital image comprising steps of:
- (A) delivering a predetermined amount of energy to each print head element in a first subset of n1 of the plurality of print head elements during a first period of time to print a first part of said first line of said digital image;
- (B) delivering the predetermined amount of energy to a second subset of n2 of the print head elements during a second period of time, n1 not being equal to n2, to print a second part of said first line of said digital image;
- wherein step (B) commences immediately after delivery of the amount of energy delivered in step (A) is terminated.
In a thermal printer comprising a plurality of print head elements, a method for providing a predetermined amount of energy to each print head element in a subset of n of the plurality of print head elements, the method comprising steps of:
- (A) selecting an amount of time tn to provide a predetermined amount of power Pn to each print head element in the subset of the plurality of print head elements, tn being a function of n, by
- (1) selecting a correction factor that is a function of n, and
- (2) calculating the value of tn by multiplying the correction factor by a predetermined amount of time to;
- and
- (B) providing the amount of power Pn to each print head element in the subset of the plurality of print head elements for amount of time tn.
A method for rendering a source target on an output medium as an output target for use in selecting a correction factor to correct energy output by electronic circuitry, the method comprising steps of:
- (A) rendering a first plurality of source regions in the source target using a first duty cycle to produce a first plurality of output regions in the output target, the first plurality of source regions including pixels having a predetermined digital value;
- and
- (B) rendering a second plurality of source regions in the source target using a predetermined set of at least three different duty cycles to produce a second plurality of output regions in the output target, the second plurality of source regions including pixels having the predetermined digital value, wherein said predetermined set of at least three duty cycles is selected independently of the number of print head elements which are active in the rendering of said second plurality of source regions.
Dependencies are inferred from the claim text.