Ink-jet printing method and apparatus therefor
AssigneeCanon Kabushiki Kaisha
InventorsNaoji Ohtsuka, Kiichiro Takahashi, Hitoshi Nishikori, Osamu Iwasaki
Life of this patent
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Abstract
Each nozzle of an ink-jet head has heaters having different heating capacities, and in accordance with the heater driven, a diameter of an ink dot formed by ink which is discharged from the nozzle is changed, thereby printing a large dot or a small dot. When multi-value image data is inputted, the multi-value image data is modulated such that a pixel having high density is printed with both the large dot and small dot. On the basis of the modulated print data, any of the heaters included in each nozzle of the ink-jet head is driven, whereby printing an image having tones based on the multi-value image data.
Claims16
An ink-jet printing apparatus for printing an image on a print medium by discharging ink from each of a plurality of printing elements of a printhead, comprising:
- ink-discharge means, provided with each of the plurality of printing elements, for discharging of an alternative amount of ink from each of the printing elements of the printhead;
- modulate means for modulating image data to generate print data for each pixel in order to print dots by using said ink-discharge means, including at least one small dot and/or large dot, corresponding to density of the image data;
- timing control means for determining a plurality of ink discharge timings in a printing cycle for each pixel, where at each ink discharge timing, the amount of ink which has been altered by said ink-discharge means is discharged;
- and
- control means for outputting print data generated by said modulate means to the printhead in synchronization with each corresponding ink discharge timing determined by said timing control means,
- wherein said modulate means generates the print data such that the print head discharges the alternative amount of ink in the plurality of ink discharge timings based on the print data in an area in which the density of the image data changes.
An ink-jet printing apparatus for performing printing by relatively moving a print medium and a printhead, comprising:
- ink-discharge means for discharging an alternative amount of ink from the printhead;
- modulate means for modulating multi-value image data to generate print data for each pixel, on which at least one small dot and a large dot is printed to express a pixel of the multi-value image data by using said ink-discharging means;
- timing control means for determining a plurality of ink discharge timings in a printing cycle for each pixel, where at each ink discharge timing, the amount of ink which has been altered by said ink-discharge means is discharged based on the print data;
- and
- control means for outputting the print data modulated by said modulate means to the printhead in synchronization with each corresponding ink discharge timing determined by said timing control means,
- wherein each pixel of a multi-value image printed in accordance with the control of said control means is formed by at least one small dot or combination of a large dot and a small dot.
An ink-jet printing method of printing an image on a print medium by discharging ink from each of a plurality of printing elements of a printhead, comprising the steps of:
- modulating image data to generate print data in order to print dots for representing each pixel of the image data, including at least one small dot and/or large dot, corresponding to density of the image data;
- determining a plurality of ink discharge timings in a printing cycle for each pixel, where at each ink discharge timing, the amount of ink to be discharged is determined by the print data to print a large dot or a small dot;
- and
- printing an image on the print medium by outputting the print data modulated in said modulating step in synchronization with each corresponding ink discharge timing,
- wherein the printhead discharges ink in the plurality of ink discharge timings based on the print data in an area in which the density of the image data changes.
An ink-jet printing method for performing printing by relatively moving a print medium and a printhead, comprising the steps of:
- modulating multi-value image data to generate print data for driving heating elements, each of which is provided with each printing element of the printhead and alters an amount of ink discharged from the printhead, on which at least one of a small dot and a large dot is printed to express a pixel of the multi-value image data;
- determining a plurality of ink discharge timings in a printing cycle for each pixel, where at each ink discharge timing, the amount of ink has been altered by using the heating elements;
- and
- outputting the print data generated in said modulating step to the printhead in synchronization with each corresponding ink discharge timing determined in said determining step,
- wherein in said outputting step, each pixel of a multi-value image printed is formed by at least one small dot or combination of a large dot and a small dot.
Dependencies are inferred from the claim text.