Abstract: The printhead according to the present invention is mechanically and electrically interchangeable on an ink jet dot printer with a known head, from which it differs substantially by having a different geometrical disposition of the nozzles, arranged in two parallel vertical rows at a constant pitch of 1/150.sup.th of an inch, where the corresponding nozzles of the two rows are staggered by 1/1600.sup.th of an inch in order to allow printing with a definition of at least 600.times.600 dots/inch by performing two consecutive print passes spaced apart by a line feed movement of value equal to 1/300.sup.th of an inch.

Abstract: A method of color printing with an ink jet printing head adapted to print one strip for each color and comprising nozzles disposed in distinct groups (22) for each color, with a different number of nozzles from group to group. Each group is separated from the subsequent group by intervals (DCM, DMY) of different magnitude. The method consists of printing strips of a subsequent color only after having printed at least two strips of a first color and superimposing each subsequent color on the first of the two strips printed previously.