Printhead having efficient heater elements for small drop ejection
View Patent ↗A printhead is provided having a plurality of nozzles and a plurality of heater elements each for heating an ejectable liquid to cause ejection of a drop of the ejectable liquid from a respective one of the nozzles. Each heater element is configured such that drops having drop volumes of less than 2 picoliters are ejected with a temperature rise in the ejectable liquid of less than 40 degrees Celsius above ambient temperature.
1. A printhead comprising:
a plurality of nozzles; and
a plurality of heater elements each for heating an ejectable liquid to cause ejection of a drop of the ejectable liquid from a respective one of the nozzles, each heater element being configured such that drops having drop volumes of less than 2 picoliters are ejected with a temperature rise in the ejectable liquid of less than 40 degrees Celsius above ambient temperature.
2. A printhead according to claim 1 , wherein each heater element being configured such that the drops having drop volumes of less than 2 picoliters are ejected with a temperature rise in the ejectable liquid of less than 30 degrees Celsius above ambient temperature.
3. A printhead according to claim 2 , wherein each heater element is configured such that drops having drop volumes of less than 2 picoliters are ejected with a temperature rise in the ejectable liquid of less than 22 degrees Celsius above ambient temperature.
4. A printhead according to claim 1 , further comprising a plurality of chambers each for holding the ejectable liquid for a respective one of the nozzles.
5. A printhead according to claim 4 , wherein the chambers are formed on a substrate so as to be in communication with a supply of the ejectable liquid through the substrate.
6. A printhead according to claim 4 , wherein a plurality of the heater elements is arranged within each chamber.
7. A printhead according to claim 6 , wherein the heater elements within each chamber are formed on different layers to one another.
8. A printhead according to claim 4 , wherein each heater element is in the form of a beam suspended in the ejectable liquid held in each nozzle chamber.
9. A printhead according to claim 1 , wherein each heater element is configured such that an actuation energy of less than 500 nanojoules is required to be applied to that heater element to heat that heater element sufficiently to cause the ejection of the drop.
10. A printhead according to claim 1 , wherein the nozzles are formed in a structure having a thickness of less than 10 microns.
11. A printhead according to claim 1 , wherein each heater element is formed of solid material more than 90% of which, by atomic proportion, is constituted by at least one periodic element having an atomic number below 50.