Abstract: A thermal inkjet printhead with heater elements disposed in respective bubble forming chambers whereby each heater element is configured for receiving an energizing pulse to form a gas bubble in an ejectable liquid that causes the ejection of a drop of the ejectable liquid from the nozzle. The energizing pulse has duration less than 1.5 micro-seconds (?s) and the nozzles are “self cooling”, in the sense that in the sense that the only heat removal required by the chip is the heat removed by ejected droplets. The printhead is designed for operation with reduced pulse duration, so the amount of heat that diffuses into the liquid and the substrate prior to nucleation of the vapor bubble is reduced. This facilitates self cooling operation.

Abstract: A thermal inkjet printhead with generally planar heater elements disposed in respective bubble forming chambers, whereby the area of each heater is less than 300 ?m2. The heater area influences: 1. the energy required to heat the heater volume up to the fluid superheat limit; 2. the energy required to heat the protective coatings covering the heater to the superheat limit; 3. the heat that diffuses into the underlayer prior to bubble nucleation; and, 4. the heat that diffuses into the ink prior to bubble nucleation. Reducing the surface area of the heater reduces all of these terms and has a significant impact on the energy required to form a bubble and eject ink.