Patent ID: 7429097

Claim:
An ink jet printhead comprising: a plurality of nozzles each defining a planar ejection aperture; and a plurality of respective heater elements corresponding to each nozzle, each heater element is in the form of a suspended beam having a planar structure suspended between corresponding electrodes and extending in a plane parallel to that of the ejection aperture; wherein each heater element is arranged for being in thermal contact with a bubble forming liquid, 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, each heater element has two opposite sides parallel to the plane of the ejection aperture and is configured such that a gas bubble formed by that heater element is formed at both of said sides, and the heater elements and associated electrodes are arranged in each nozzle so that the electrodes are non-coincident.