Thermal ink jet printhead with laterally enclosed heater element

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 heater element is laterally enclosed by the interior surface of the bubble forming chamber. The nucleation and growth of a gas bubble causes the pressure pulse that ejects ink from the nozzle aperture. If the bubble is not enclosed, much of the pressure dissipates sideways instead of through the nozzle with the ejected ink.