Patent ID: 7748814

Claim:
An ink-jet recording apparatus which records an image on a recording medium comprising: ink-jet heads which eject ink droplets of black and a plurality of chromatic colors onto the recording medium; a dot position memory unit which stores therein dot positions; an image data memory unit which stores therein an image data item of the image; a print data generating unit which generates a print data item based on the image data item stored in the image data memory unit and the dot positions stored in the dot position memory unit; and a head controller which causes the ink-jet heads to eject ink droplets to the dot positions, wherein: the dot positions include black dot positions at which only ink droplets of black are ejected, and chromatic color dot positions at which only ink droplets of chromatic color ink are ejected, the black positions are evenly distributed in at least a part of the image and each of the black dot positions is distinct from each of the chromatic color dot positions; the image data item is stored in the form of dot data items each indicating grayscale values of achromatic and chromatic colors for the dot positions in the image; the print data item contains dot data items indicating the grayscale values of the achromatic colors for the black dot positions, and the grayscale values of the chromatic colors for the chromatic color dot positions, wherein the dot data items indicate that the grayscale values of the chromatic colors are at values with which no ink droplet is ejected for the black dot positions and that the grayscale values of the black color are at values with which no ink droplet is ejected for the chromatic color dot positions; and the head controller causes the ink-jet heads to eject the ink droplets to the dot positions, so that: only the ink droplets of black are ejected in the black dot positions stored in the dot position memory unit; and only the ink droplets of the chromatic colors are ejected in the chromatic color dot positions stored in the dot position memory unit, a volume of each of the ink droplets respectively corresponds to the grayscale values associated to the dot positions indicated by the print data item generated by the print data generating unit.