Nozzle arrangement with rectilinear ink ejection
View Patent ↗Provided is a nozzle arrangement for an ink jet printer. The arrangement includes a wafer substrate with a layer of drive circuitry, said substrate defining an ink supply channel through the substrate leading to an ink chamber with a roof defining an ink ejection port. The arrangement also includes an ink ejection arrangement for ejecting ink from the ink chamber via the port, said ink ejection arrangement having four symmetrically arranged thermal bend actuators each connected to a respective side to ensure that the roof is operatively displaced in a rectilinear manner during ink ejection.
1. A nozzle arrangement for an ink jet printer, said arrangement comprising:
a wafer substrate with a layer of drive circuitry, said substrate defining an ink supply channel through the substrate;
sidewalls and a roof defining an ink chamber in fluid communication with the ink supply channel, the roof defining an ink ejection port in fluid communication with the ink chamber; and
an ink ejection arrangement for ejecting ink from the ink chamber via the port, said ink ejection arrangement having four symmetrically arranged thermal bend actuators each connected to a respective side to ensure that the roof is operatively displaced in a rectilinear manner during ink ejection.
2. The nozzle arrangement of claim 1 , which includes a static ink ejection structure having an inner wall and an outer wall that together define a wall portion, an inwardly directed ledge being positioned on the inner wall so that said ledge extends into the nozzle chamber.
3. The nozzle arrangement of claim 2 , having a sealing formation which is positioned on the outer wall to extend outwardly from the wall portion so that the sealing formation and the ledge define an ink displacement formation.
4. The nozzle arrangement of claim 3 , wherein the sealing formation includes a re-entrant portion that opens towards the substrate with a lip positioned on the re-entrant portion to extend horizontally from the re-entrant portion.
5. The nozzle arrangement of claim 4 , wherein the sealing formation and the sidewalls 24 are configured so that, when the nozzle arrangement is in a quiescent condition, the lip and a free edge of the sidewalls are in horizontal alignment with each other, so that a distance between the lip and the free edge is such that an ink meniscus is defined between the sealing formation and the free edge when the nozzle chamber is filled with the ink.
6. The nozzle arrangement of claim 5 , wherein when the nozzle arrangement is in an operative condition, the free edge is interposed between the lip and the substrate and the meniscus stretches to accommodate such movement, so that when the chamber is filled with ink, a fluidic seal is defined between the sealing formation and the free edge of the sidewalls.
7. The nozzle arrangement of claim 1 , wherein rectilinear movement of the ink ejection structure results in clean drop formation and separation.