Patent attributes
An inkjet printhead integrated circuit that has a plurality of nozzles 3 and a bubble forming chamber 7 corresponding to each nozzle respectively. At least one heater element 10 suspended in each bubble forming chamber 7 to heat a bubble forming liquid 11 to a temperature above its boiling point to form a gas bubble 12 therein. The generation of the bubble 12 causes the ejection of a drop 16 of an ejectable liquid (such as ink) through an ejection aperture 5 in each nozzle 3, to effect printing. The heater element has a rotatable section configured such that the strain of thermal expansion is relieved by rotation of the rotatable section within the plane of the heater element. The heater elements are formed by depositing a thin strip of heater material, usually less than 1 micron thick. Repeated bending of the element can lead to oxidation and embrittlement, especially at small radius bends. This, in turn, leads to cracking and ultimately failure. Heater elements according to this invention are configured so that the thermal expansion is accommodated by the rotation of a section within the plane of lamination.
