Nozzle arrangement with different sized heater elements
A nozzle arrangement for ejecting ink comprises a substrate assembly defining an ink supply passage and incorporating a drive circuitry layer; a heater positioned on the substrate assembly, the heater having a pair of heater elements connected to electrical contacts, which electrical contacts are electrically coupled to the drive circuitry layer; and a nozzle chamber structure extending from said heater to define a nozzle chamber in fluid communication with the ink supply passage and in which the heater element is located, the nozzle chamber structure defining an aperture through which ink in the nozzle chamber is ejected when current is supplied from the drive circuitry layer to the heater element. The electrical contacts each have an enlarged cross-sectional area relative to the cross-section area of the heater element. A first heater element of the pair of heater elements has a surface area larger than that of the second heater element of the pair of heater elements.
1. A nozzle arrangement for ejecting ink, the nozzle arrangement comprising:
a substrate assembly defining an ink supply passage and incorporating a drive circuitry layer;
a heater positioned on the substrate assembly, the heater having a pair of heater elements connected to electrical contacts, which electrical contacts are electrically coupled to the drive circuitry layer; and
a nozzle chamber structure extending from said heater to define a nozzle chamber in fluid communication with the ink supply passage and in which the heater element is located, the nozzle chamber structure defining an aperture through which ink in the nozzle chamber is ejected when current is supplied from the drive circuitry layer to the heater element, wherein
the electrical contacts each have an enlarged cross-sectional area relative to the cross-section area of the heater element, and
a first heater element of the pair of heater elements has a surface area larger than that of the second heater element of the pair of heater elements.
2. A nozzle arrangement as claimed in claim 1 , wherein the ink supply passage narrows as it approaches the nozzle chamber to constrict the flow of ink supplied to the nozzle chamber.
3. A nozzle arrangement as claimed in claim 1 , wherein the substrate assembly includes:
a substrate;
the drive circuitry layer deposited on the substrate;
an interconnect layer deposited on the drive circuitry layer and electrically connecting the electrical contacts to the drive circuitry layer; and
a passivation layer deposited on the interconnect layer.
4. A nozzle arrangement as claimed in claim 1 , wherein at least one of the heater elements includes an arcuate portion.
5. A nozzle arrangement as claimed in claim 4 , wherein at least one of the heater elements is shaped to define a broken annulus having the arcuate portion.
6. A nozzle arrangement as claimed in claim 5 , wherein at least one of the heater elements heater element is shaped to define a plurality of concentric broken annuli.
7. A nozzle arrangement as claimed in claim 1 , wherein said nozzle chamber structure defines a protruding rim bounding the aperture and surrounded by an endless ink collection well.