Method and apparatus for ejecting ink droplets onto a substrate

An apparatus for ejecting an ink, comprising:

• an ink jet head mounting thereon N ink jet nozzles (where N is an integer not smaller than 2) arranged in an array;
• an X-Y table for mounting thereon a substrate;
• and a controller, wherein the controller is configured to control the ink jet head and/or the X-Y table to:
• cause a first excursion of the ink jet head with respect to the substrate along a first direction perpendicular to an extending direction of the array, said first excursion being accompanied by ink ejection from the ink jet nozzles to provide a first ejection area of the ink droplets on the substrate;
• cause a second excursion of the ink-jet head, alternately with the first excursion, with respect to the substrate along the first direction, said second excursion being accompanied by ink ejection from the ink jet nozzles to provide a second ejection area of the ink droplets on the substrate;
• cause a third excursion of the ink jet head, between the first excursion and the second excursion, with respect to the substrate in a direction parallel to the extending direction of the array, wherein:
• the first ejection area and the second ejection area having therebetween an overlapping excursion of at least two of the ink jet nozzles, and at least one of the at least two of the ink jet nozzles does not eject the ink during either the first excursion or the second excursion, the at least one excluding an outermost one of the ink jet nozzles.