Ink jet printing method and ink jet printing apparatus

An ink jet printing apparatus for causing a plurality of nozzles arranged in a print head to eject ink droplets while the print head scans relative to a print medium, to print an image on the print medium, the apparatus comprising:

• scanning means for scanning the print head to a same print region of the print medium a plurality of times;
• conversion means for converting multivalued image data that corresponds to the respective pixels constituting an image to be printed on the same print region to binary image data;
• thinning-out means for thinning-out the binary image data corresponding to the same print region by using different mask patterns corresponding to respective plurality of scans to the same print region;
• and
• printing control means for printing, based on the binary image data thinned out by the thinning-out means in the respective plurality of scans, a thinned-out image on the same print region to complete the image to be printed on the same print region;
• wherein the respective different mask patterns are defined so that a first region for thinning-out the binary image data with a relatively high thinning-out ratio and a second region for thinning-out the binary image data with a relatively low thinning-out ratio are repeatedly arranged in a direction, in which the nozzles are arranged, in the unit of an integral multiple of the width of the pixel.

An ink jet printing method for causing a plurality of nozzles arranged in a print head to eject ink droplets while the print head scans relative to a print medium, to print an image on the print medium, the method comprising:

• a scanning step for scanning the print head to scan a same printing region of the print medium a plurality of times;
• a thinning-out step for dividing image data corresponding to the same print region to image data to be printed in the respective plurality of scans by thinning-out image data corresponding to the same print region;
• and
• a printing step for printing thinned-out image on the same print region in accordance with image data thinned out by the thinning-out step in the respective plurality of main scans to complete an image to be printed on the same print region,
• wherein, in the thinning-out step, image data to be printed on a plurality of the same print regions at which a nozzle array of the print head passes during one scan is thinned out at high and low thinning-out ratios alternately in a direction in which the nozzles are arranged.

An ink jet printing method for causing a plurality of nozzles arranged in a print head to eject ink droplets while the print head scans relative to a print medium to form an image on the print medium, the method comprising:

• a step for causing the print head to scan to a same print region of the print medium a plurality of times;
• a step for converting multivalued image data that corresponds to the respective pixels constituting an image to be printed on the same print region to binary image data;
• a step for thinning-out binary image data corresponding to the same print region using different mask patterns respectively corresponding to a plurality of scans to the same print region;
• and
• a step for printing, in the respective plurality of scans, thinned-out images on the same print region based on the thinned-out binary image data to complete an image to be printed on the same print region,
• wherein the respective different mask patterns include an arrangement of an region in which a printing of the binary image data is permitted and an region in which a printing of the binary image data is not permitted and are defined so that a part relatively highly occupied by the printing-permitted region and a part relatively lowly occupied by the printing-permitted region are repeatedly arranged along a direction, in which the nozzles are arranged, in the unit of an integral multiple of the width of the pixel.