Inkjet Nozzle Device With Cantilevered Actuating Arm

Abstract

A nozzle device for an inkjet printer includes a support structure defining an ink chamber connected to a source of ink; a nozzle chamber for receiving ink from the ink chamber; a nozzle opening through which ink in the nozzle chamber is ejected; and an elongate actuating arm cantilevered relative to the support structure and terminating in a movable free end within the nozzle chamber, the actuating arm comprising an active portion connected electrically to a current source and a passive portion electrically isolated from the current source. The passive portion is mechanically coupled to the active portion via at least one separating element, whereby differential expansion between the active and passive portions causes the actuating arm to bend and the free end of the actuating arm to move within the nozzle chamber to eject ink therein through the nozzle opening. The elongate actuating arm divides the nozzle chamber from the ink chamber.

1 . A nozzle device for an inkjet printer, the nozzle device comprising:
 a support structure defining an ink chamber connected to a source of ink;   a nozzle chamber for receiving ink from the ink chamber;   a nozzle opening through which ink in the nozzle chamber is ejected; and   an elongate actuating arm cantilevered relative to the support structure and terminating in a movable free end within the nozzle chamber, the actuating arm comprising an active portion connected electrically to a current source and a passive portion electrically isolated from the current source, wherein   the passive portion is mechanically coupled to the active portion via at least one separating element, whereby differential expansion between the active and passive portions causes the actuating arm to bend and the free end of the actuating arm to move within the nozzle chamber to eject ink therein through the nozzle opening, and   the elongate actuating arm divides the nozzle chamber from the ink chamber.   
     
     
         2 . A nozzle device as claimed in  claim 1 , further comprising a movement sensor for determining the degree or rate of pivotal movement of the actuating arm. 
     
     
         3 . A nozzle device as claimed in  claim 2 , wherein the movement sensor comprises a movable contact element extending from the active portion, and a fixed contact element extending from the support structure in a position, the movable contact element adapted to contact the fixed contact element upon activation of the current source. 
     
     
         4 . A nozzle device as claimed in  claim 3 , wherein the active portion is substantially U-shaped and the movable contact element is located proximal to the centre of the active portion. 
     
     
         5 . A nozzle device as claimed in  claim 4 , wherein the free ends of the active portion define a pair of enlarged contacts. 
     
     
         6 . A nozzle device as claimed in  claim 1 , wherein the nozzle chamber comprises:
 a static portion extending from the support structure, defining the nozzle opening; and   a movable wall portion mounted to the cantilevered actuating arm between the fixed and free ends of the actuating arm.   
     
     
         7 . A nozzle device as claimed in  claim 6 , wherein the static formation extends from the support structure towards the actuating arm at a location proximal to the movable wall portion, the static formation impeding the escape of ink from within the nozzle chamber during actuation of the actuating arm, whereby an ink meniscus is formed between the static formation and the actuating arm. 
     
     
         8 . A nozzle device as claimed in  claim 7 , wherein the static formation defines a bent free end which bends away from the nozzle chamber. 
     
     
         9 . A nozzle device as claimed in  claim 8 , wherein the support structure defines a well located in alignment with the bent free end, the well collecting any escaped ink from the nozzle chamber. 
     
     
         10 . A nozzle device as claimed in  claim 1 , wherein the free end of the actuating arm comprises a paddle spanning the nozzle chamber.