Patent ID: 7156495

Claim:
An ink jet printhead comprising a substrate having a plurality of nozzle arrangements formed therein, at least one of said nozzle arrangements comprising: an ink chamber formed in said substrate; a rim disposed over the chamber and defining an ink ejection port; and a wall extending over said chamber, said wall including at least one flexible portion and being actuatable to cause bending of said wall at said flexible portion; whereby the wall is adapted to move independently of said rim such that upon actuation of the wall, the at least one flexible portion displaces into said ink chamber forcing ink therein, out through the said ink ejection port; wherein the said at least one flexible portion of said wall is made from material having a thermal expansion suitable to cause the wall to move into said ink chamber upon uneven heating of the at least one flexible portion of the wall; and wherein the printhead further includes one or more rib elements located on an outer surface of said wall that interact with the flexible portion to ensure bending of the wall into said chamber.