Patent ID: 7175257

Claim:
An ink-jet printhead comprising: a substrate having an ink chamber having a predetermined volume and formed on a first surface of the substrate, and having a passage supplying ink to the ink chamber formed on a second surface of the substrate; a nozzle plate having a nozzle corresponding to a center of the ink chamber, and having at least two insulating layers formed on the substrate; a bubble guide formed on an inside surface of the nozzle plate to define the nozzle, through which the ink is ejected, and extending from the nozzle into the ink chamber; a heater which surrounds the nozzle and is disposed between the two insulating layers; a hydrophobic coating layer formed on a surface of an uppermost outside layer of the nozzle plate; and a droplet ejecting portion formed on the hydrophobic coating layer to have a diameter smaller than that of the nozzle of the nozzle plate, and disposed on the same axis as the nozzle, wherein the droplet ejecting portion comprises: a surface having the diameter that is reduced gradually in a droplet progressing direction.