PRINTING DEVICE, PRINTING METHOD AND PROGRAM THEREOF

• US 20140218431A1
• Filed: 04/07/2014
• Published: 08/07/2014
• Est. Priority Date: 11/15/2011
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: KAKUTANI, Toshiaki
• Granted Patent: US 8,928,934 B2
• Time in Patent Office: Days
• US Class Current: 347/15
• CPC Class Codes: B41J 2/2121 characterised by dot size, e.g. combinations of printed dots of different diameter
• CPC Class Codes: G06K 15/10 by matrix printers G06K15/028 takes precedence
• CPC Class Codes: H04N 1/405 Halftoning, i.e. converting the picture signal of a continuous-tone original into a corresponding signal showing only two levels
• CPC Class Codes: H04N 1/502 Reproducing the colour component signals dot-sequentially or simultaneously in a single or in adjacent picture-element positions

Abstract

A printing device includes the following features. The first dot group in which dots are formed based on the first printing condition and the second dot group in which dots are formed based on a printing condition which is different from the first printing condition are formed together in a common region. In the common region, when the printing is performed in a plurality of conditions such that a difference of the dot pitch between a formation position of dots belonging to the first pixel group and a formation position of dots belonging to the second pixel group is 2/720 inch to 5/720 inch, the change in CIEL*a*b* of the printed image is within the preliminary determined range.

Claims

1. A printing device for printing and forming dots on a printing medium comprising:

a printing unit that prints an image;

wherein the printing of the image is performed such that when the dots are formed on the printing medium in accordance with dot data indicating existence or non-existence of a dot formation per each pixel, the dot formation is divided into at least first and second pixel groups, and at least a portion of dot formation in the first and second pixel groups is performed in a common region;

wherein the printing unit includes a print head for performing a color printing by multiple color dots in a resolution N (N is a natural number of more than

     180) dot per inch (dpi), and when the printing is performed in each of a plurality of conditions of which a relative position between the first pixel group and the second pixel group is different, at least one of following conditions is satisfied;

(A) when the printed image is yellow (RGB value;

R=G=255, B=0 to 64, when RGB value is 8 bit conversion), color difference in CIEL*a*b* color space of images printed in each of the plurality of different conditions is less than value 2 as a change of b*;

(B) when the printed image is magenta (RGB value;

R=B=255, G=0 to 64, when RGB value is 8 bit conversion), the color difference in CIEL*a*b* color space of the images printed in each of the plurality of different conditions is less than value 0.5 as a change of L* or less than value 0.5 as a change of a*; and

(C) when the printed image is cyan (RGB value;

G=B=255, R=0 to 64, when RGB value is 8 bit conversion), the color difference in CIEL*a*b* color space of the images printed in each of the plurality of different conditions is less than value 0.5 as a change of L*.