Method and apparatus using two different black inks to reduce intercolor

Abstract

A color ink jet printing device capable of substantially reduced intercolor bleeding includes an ink jet printer having at least one printhead and at least three separate ink supplies in communication with the printhead. A first ink supply contains a slow drying black ink. A second ink supply contains a fast drying black ink. A third ink supply contains a fast drying non-black color ink. Prior to printing, black image potions are determined. The black portions are printed using a pixel priming process, a border substitution process or a combination thereof to reduce intercolor bleed. The pixel priming process first prints a quartertone or halftone pattern using fast drying black ink, followed by subsequent whole tone printing superposed on the primed black image area using a slow drying black ink. The border substitution process analyzes a neighboring matrix of pixels surrounding each black pixel, preferably at least a 5.times.5 matrix, to determine if color pixels other than black are present. If so, that black pixel is printed using the fast drying black ink to reduce intercolor bleed. Otherwise, the black pixel is printed using slow drying black ink. This printing may be further improved by checkerboarding the black image portions. This involves printing a partial tone checkerboard pattern in a first pass and printing a complementary checkerboard pattern on a second pass to provide a whole tone of the image portions.