Printhead nozzles having low mass heater elements
View Patent ↗Provided is a printhead having a plurality of nozzles formed on a wafer substrate. Each nozzle has a fluid chamber for holding printing fluid, the fluid chamber having an ejection port, a fluid inlet defined in the wafer substrate for supplying the fluid chamber with printing fluid, and a heater element suspended in the fluid chamber. The heater element has a mass of less than 10 nanograms. Upon application of electrical energy to the heater element, a vapor bubble is formed in the printing fluid, thereby ejecting the fluid via the ejection port.
1. A printhead having a plurality of nozzles formed on a wafer substrate, each nozzle comprising:
a fluid chamber for holding printing fluid, the fluid chamber having an ejection port;
a fluid inlet defined in the wafer substrate for supplying the fluid chamber with printing fluid; and
a heater element suspended in the fluid chamber, the heater element having a mass of less than 10 nanograms wherein, upon application of electrical energy to the heater element, a vapour bubble is formed in the printing fluid, thereby ejecting the fluid via the ejection port.
2. The printhead of claim 1 wherein the heater element is planar and configured so that a point of collapse of the bubble is distal therefrom.
3. The printhead of claim 2 , wherein the heater element has an annular shape with the point of collapse of the bubble near a centre thereof.
4. The printhead of claim 1 , wherein said mass of the heater element is less than 2 nanograms.
5. The printhead of claim 1 , wherein said mass of the heater element is less than 500 picograms.
6. The printhead of claim 1 , wherein said mass of the heater element is less than 250 picograms.
7. The printhead of claim 1 , having a nozzle density of more than 10,000 nozzles per square cm of substrate surface.
8. The printhead of claim 1 , wherein the electrical energy applied to the heater element for ejecting the fluid is less than 500 nanojoules.