Inkjet printhead incorporating multiple heater elements for weighted ink drop ejection
View Patent ↗A pagewidth printhead includes a printhead controller; a wafer substrate defining a plurality of inlets; and a plurality of micro-electromechanical nozzle arrangements on the wafer substrate and under control of the controller. Each nozzle arrangement includes side walls disposed on the wafer substrate with a roof portion attached to said side walls to define a printing fluid chamber in fluid communication with one inlet, the roof portion defining an ejection port; and at least two heater elements suspended between the side walls in the fluid chamber for forming a vapour bubble in response to electrical actuation energy being applied thereto, whereby a pressure increase in the chamber is effected and fluid in the fluid chamber ejected therefrom via the ejection port. The controller is configured to actuate the at least two heater elements individually to facilitate ejection of weighted ink drop volumes from the nozzle arrangement. A size of a first of the at least two heater elements is different to a size of a second of the at least two heater elements.
1. A pagewidth printhead comprising:
a printhead controller;
a wafer substrate defining a plurality of inlets; and
a plurality of micro-electromechanical nozzle arrangements on the wafer substrate and under control of the controller, each nozzle arrangement comprising:
side walls disposed on the wafer substrate with a roof portion attached to said side walls to define a printing fluid chamber in fluid communication with one inlet, the roof portion defining an ejection port;
at least two heater elements suspended between the side walls in the fluid chamber for forming a vapour bubble in response to electrical actuation energy being applied thereto, whereby a pressure increase in the chamber is effected and fluid in the fluid chamber ejected therefrom via the ejection port, wherein
the controller is configured to actuate the at least two heater elements individually to facilitate ejection of weighted ink drop volumes from the nozzle arrangement, and
a size of a first of the at least two heater elements is different to a size of a second of the at least two heater elements.
2. The pagewidth printhead of claim 1 , wherein each of the at least two heater elements are configured so that a point of collapse of the bubble is distal therefrom.
3. The pagewidth printhead of claim 1 , wherein each of the at least two heater elements has an annular shape with the point of collapse of the bubble near a centre thereof.
4. The pagewidth printhead of claim 3 , wherein the heater elements are concentrically arranged on top of each other.
5. The pagewidth printhead of claim 4 , wherein the first of the at least two heater elements is below the second of the at least two heater elements.
6. The pagewidth printhead of claim 5 , wherein the first of the at least two heater elements is larger than the second of the at least two heater elements.
7. The pagewidth printhead of claim 6 , wherein the first of the at least two heater elements has an area twice that of the second of the at least two heater elements.
8. The pagewidth printhead of claim 1 , wherein a mass of each of the at least two heater elements is less than 500 picograms.
9. The pagewidth printhead of claim 1 , wherein a mass each of the at least two heater elements is less than 250 picograms.