Patent ID: 7070253
Filing Date: 2006-07-04
Classification: B41J

Abstract:
1. An ink-jet printing apparatus which performs multilevel printing by using a plurality of types of inks having different densities for similar colors when used for printing, and changing the types of inks and the numbers of ink droplets in printing each pixel, comprising: input means for inputting information associated with relative densities for the respective inks in case of being used for printing; table generation means for generating, on the basis of the information associated with the relative densities, an ink distribution table for defining a combination of the types of inks and the numbers of ink droplets in correspondence with each gray level value; combination selection means for selecting, on the basis of the ink distribution table, the combination to be used to print each pixel, wherein the ink distribution table defines a plurality of combinations of the types of inks and numbers of the ink droplets for some grey level value; and reference combination input means for inputting a combination of the types of inks and the numbers of ink droplets which exhibit a predetermined density as a reference combination, wherein said table generation means generates, on the basis of information associated with the relative densities and the reference combination, the ink distribution table which defines a correspondence between various combinations of the types of inks and the numbers of ink droplets and gray level values printed by the respective combinations, wherein said table generation means includes reference value calculating means for expressing the sum of the ratios with respect to ink droplets contained in each combination as a density reference value with respect to the sum of the ratios with respect to ink droplets contained in the reference combination, and conversion means for converting the density reference value into the gray level value.