Printing apparatus, printing method and image processor

A printing method to print an image on a print medium by scanning a print head for printing dots on the print medium, comprising:

• a conversion step converting image data for a grayscale expression in one pixel into print data determining each of a plurality of subpixels making up the one pixel either to be printed or not to be printed with dot according to a plurality of dot arrangement patterns that determine each of the plurality of subpixels making up the one pixel either as a subpixel to be printed or as a subpixel not to be printed;
• and
• a print step causing the print head to perform a plurality of scans according to the print data to print an image in a unit area on the print medium;
• wherein the plurality of dot arrangement patterns are constructed such that
• (i) as the number of dot determined to be printed in the plurality of subpixels increase, a ratio of the number of subpixel determined to be printed with plural dot to the number of subpixel determined to be printed with one or more (overlapping ratio) increase, and
• (ii) regardless the number of dot to be printed in the plurality of subpixels, a ratio the number of the subpixel determined to be printed adjoining one subpixel in focus, to the number of the subpixel adjoining the subpixel in focus is larger than 0% and lower than 100%.

An image processor for processing print data used in printing apparatus to print an image on a print medium by scanning a print head for printing dots on the print medium, comprising:

• a conversion unit configured to convert image data for a grayscale expression in one pixel into print data determining each of a plurality of subpixels making up the one pixel either to be printed or not to be printed with dot according to a plurality of dot arrangement patterns that determine each of the plurality of subpixels making up the one pixel either as a subpixel to be printed or as a subpixel not to be printed,
• wherein the plurality of dot arrangement patterns are constructed such that
• (i) as the number of dot determined to be printed in the plurality of subpixels increase, a ratio of the number of subpixel determined to be printed with plural dot to the number of subpixel determined to be printed with one or more dot (overlapping ratio) increase, and
• (ii) regardless the number of dot to be printed in the plurality of subpixels, a ratio the number of the subpixel determined to be printed adjoining one subpixel in focus, to the number of the subpixel adjoining the subpixel in focus is larger than 0% and lower than 100%.