Printing Integrated Circuit Having Piston Ejection

Abstract

A printing integrated circuit is provided which has a substrate, fluid chambers on the substrate, pistons within the chambers and actuators connected to the pistons. Each chamber has an ejection port. Each piston is displaceable within the respective chamber to generate a fluid pressure pulse within that chamber thereby causing fluid ejection from the respective ejection port. Each actuator is configured to cause the displacement of the respective piston through heating of that actuator. The pistons are arranged in the chambers so that the ejection ports are adjacent a distal end portion of the pistons with respect to the connected actuators.

1 . A printing integrated circuit comprising:
 a substrate;   fluid chambers on the substrate, each chamber having an ejection port;   pistons within the chambers, each piston being displaceable within the respective chamber to generate a fluid pressure pulse within that chamber thereby causing fluid ejection from the respective ejection port; and   actuators connected to the pistons, each actuator being configured to cause said displacement of the respective piston through heating of that actuator,   wherein the pistons are arranged in the chambers so that the ejection ports are adjacent a distal end portion of the pistons with respect to the connected actuators.   
   
   
       2 . An integrated circuit as claimed in  claim 1 , wherein the actuators are connected to a CMOS circuitry layer of the substrate via which heating electric current is communicated to the actuators. 
   
   
       3 . An integrated circuit as claimed in  claim 1 , wherein the pistons each have a surface area that is a predetermined order of magnitude larger than an opening area of the ejection ports so that a hydraulic advantage is achieved. 
   
   
       4 . An integrated circuit as claimed in  claim 1 , wherein the actuators are configured so that said displacement of the pistons is a predetermined order of magnitude greater than displacement of the actuators.