Printhead having planar bubble nucleating heaters

摘要

A printhead is provided having a plurality of bubble forming chambers, ejection nozzles defined in the chambers, and heaters disposed in the chambers for heating bubble forming liquid in the chambers. Each heater has a bubble nucleation section of a smaller cross section than the rest of that heater. The bubble nucleation section is heated faster that the rest of the heater to cause formation of a gas bubble in the liquid and ejection of the bubbled liquid through the corresponding nozzle. The bubble nucleation section is co-planar with the rest of that heater and remains co-planar when the heater is heated.