Thermal ink jet printhead with bubble collapse point void

摘要

There is disclosed an ink jet printhead which comprises a plurality of nozzles 3 and one or more heater elements 10 in a bubble forming chamber 7 corresponding to each nozzle 3. Each heater element 10 is configured to heat a bubble forming liquid 11 in the printhead 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 gas bubble subsequently collapses to a point of collapse 17 that is spaced from any solid surface of the heater elements 10 or the bubble forming chamber 7. By configuring the heater elements within the bubble forming chamber such the points of collapse of the bubbles are not on any solid surfaces, the corrosive effects of cavitation can be avoided.