INKJET NOZZLE ARRANGEMENT WITH DISPLACEABLE PARTIAL CHAMBER WALL
A nozzle arrangement includes a wafer substrate defining an inlet channel; a nozzle chamber wall and a roof wall provided on the wafer substrate to define a nozzle chamber in fluid communication with the inlet channel, the roof wall defining an ink ejection port and the nozzle chamber wall defining a first gap; a paddle positioned in the nozzle chamber and reciprocally displaceable to eject ink from the ejection port; an actuating arm connected to the paddle, the actuating arm having a pair of actuating members and a heating circuit connected to one of the actuating members, and a sealing structure supported on the actuating arm, the sealing structure being positioned in first gap. The pair of actuating members comprise a resiliently flexible material. On receipt of an electrical signal, the actuating arm is displaced in a first direction, and on cessation of the electrical signal the actuating arm is displaced in a second direction opposite to the first direction.
1 . A nozzle arrangement for an inkjet printhead, the nozzle arrangement comprising:
a wafer substrate defining an inlet channel;
a nozzle chamber wall and a roof wall provided on the wafer substrate to define a nozzle chamber in fluid communication with the inlet channel, the roof wall defining an ink ejection port and the nozzle chamber wall defining a first gap;
a paddle positioned in the nozzle chamber and reciprocally displaceable to eject ink from the ejection port;
an actuating arm connected to the paddle, the actuating arm having a pair of actuating members and a heating circuit connected to one of the actuating members, and
a sealing structure supported on the actuating arm, the sealing structure being positioned in first gap, wherein
the pair of actuating members comprise a resiliently flexible material, and
on receipt of an electrical signal, the actuating arm is displaced in a first direction, and on cessation of the electrical signal the actuating arm is displaced in a second direction opposite to the first direction.
2 . A nozzle arrangement as claimed in claim 1 , wherein the actuating members are oriented with one actuating member interposed between the substrate and the other actuating member, whereby said reciprocal displacement is with respect to the substrate.
3 . A nozzle arrangement as claimed in claim 1 , wherein the actuating members are arranged to define a gap therebetween, whereby buckling of the actuating arm is avoided.
4 . A nozzle arrangement as claimed in claim 1 , wherein a raised formation is positioned on an upper surface of the paddle to inhibit the paddle from making contact with a meniscus formed at the ejection port.
5 . A nozzle arrangement as claimed in claim 1 , wherein a nozzle rim is positioned about the ejection port.
6 . A nozzle arrangement as claimed in claim 1 , wherein the sealing structure is displaced with the actuating arm.
7 . A nozzle arrangement as claimed in claim 1 , wherein the sealing structure forms a surface tension fluidic seal with the roof wall and the nozzle chamber wall.