Patent ID: 6834936
Filing Date: 2004-12-28
Classification: B41J

Abstract:
An ink jet printing apparatus for printing a color image by using a print head having a plurality of print elements, the printing being performed by scanning the print head over one and the same scan area a plurality of times and by applying a plurality of color inks from the plurality of print elements to a print medium in both forward and backward directions of the scan, the print head including two print element array portions for each color disposed in a print head scanning direction, one of the two print element array portions being symmetric to the other print element array portion in an arrangement of ink colors, the plurality of print elements in one of the two print element array portions being shifted from the plurality of print elements in the other print element array portion in a direction of arrays of the print elements, said apparatus comprising:a spread pattern to arrange secondary color pixel data uniformly in a raster direction, said spread pattern being used to determine an ink application position in a pixel area; a data spreading means to generate the pixel data according to the spread pattern; and a spread pattern changing means to change the spread pattern used by said data spreading means according to a state of print data.