Abstract: An ink jet printing apparatus is provided comprising a print cartridge including a heater chip and a nozzle plate coupled to the heater chip. The heater chip has first, second, third and fourth heating elements, and the nozzle plate has a plurality of primary and secondary nozzles. The primary nozzles include first and second nozzles positioned in first and second nozzle plate columns and the secondary nozzles include third and fourth nozzles positioned in third and fourth nozzle plate columns. Each of the nozzles has one of the heating elements associated therewith for generating energy to discharge ink therefrom. The apparatus further includes a driver circuit, electrically coupled to the print cartridge, for applying firing pulses to the heating elements. The printing apparatus is selectively operable in one of a normal mode of operation and a high speed mode of operation.

Abstract: An increased resolution thermal ink jet printhead construction and method for forming large array heater chips for thermal ink jet printheads is achieved by fabricating a unitary "megachip" in which multiple cells of electrical components are defined in a plurality of columnar patterns in a plane of a silicon wafer. Cells of a first column are vertically offset from cells of an adjacent column so as to overlap the gap between cells in the first column. The megachip is then formed by grouping at least one cell from each of two adjacent columns and dicing the wafer to remove the megachip.