Ink-jet printer and ink jetting method

An ink-jet printer which performs recording on a recording medium by jetting a black ink, a yellow ink, a magenta ink, and a cyan ink, the ink-jet printer comprising:

• an ink-jet head including black, cyan, magenta and yellow nozzle rows each of which is formed of a plurality of nozzles arranged in a predetermined direction, and which are aligned in a direction orthogonal to the predetermined direction;
• and
• a controller which controls the ink-jet head;
• wherein adjacent nozzles, among the nozzles in each of the nozzle rows, are arranged at a predetermined spacing distance P;
• the black nozzle row is shifted, in the predetermined direction by a spacing distance ΔP smaller than the predetermined spacing distance P, from the cyan, magenta and yellow nozzle rows, respectively;
• when a black dot is formed between monochrome-black dots of monochrome black which are adjacent to each other in the predetermined direction and which are formed by jetting the black ink, the controller controls the ink-jet head so that the yellow ink, the magenta ink, and the cyan ink are jetted from nozzles to form a color-mixed black dot of color-mixed black which is a mixture of the yellow ink, the magenta ink, and the cyan ink;
• and
• the controller controls the ink-jet head so that an amount of the black ink which is jetted to form one dot of the monochrome-black dots is greater than a total amount of the yellow ink, the magenta ink, and the cyan ink jetted to form the color-mixed black dot.