Patent ID: 7278717

Claim:
An ink jet printhead comprising: a plurality of nozzles formed as coplanar apertures; and at least one respective heater element corresponding to each nozzle, wherein each heater element is in the form of a suspended beam, the suspended beam being generally planar such that it has two opposed planar surfaces joined by edge surfaces, the opposed planar surfaces having surface area greater than that of the edge surfaces, wherein during use, the suspended beam is suspended over at least a portion of a bubble forming liquid so as to be in thermal contact therewith, and each heater element is configured to heat at least part of the bubble forming liquid to a temperature above its boiling point to form a gas bubble therein, thereby to cause the ejection of a drop of an ejectable liquid through the nozzle corresponding to that heater element; wherein, the planar surfaces of the heater element are parallel with the plane of the corresponding nozzle.