Patent ID: 6655787
Filing Date: 2003-12-02
Classification: B41J

Abstract:
An emission device for ejecting a liquid drop, said device comprising:a chamber of variable volume adapted to receive a liquid and having a nozzle orifice through which a drop of received liquid can be emitted; a first membrane associated with the chamber such that movement of the first membrane in a first direction increases the chamber volume to draw liquid into the chamber; a second membrane associated with the chamber such that movement of the second membrane in a second direction decreases the chamber volume to emit a liquid drop through the nozzle orifice; and a mandrel between the first and second membranes such that (1) application of a voltage differential between the first membrane and the mandrel moves the first membrane in said first direction to increase the chamber volume and (2) application of a voltage differential between the second membrane and the mandrel moves the second membrane in said second direction to decrease the chamber volume, said mandrel having substantially planar opposed surfaces respectively facing each of said first and second membranes at an angle of contact such that least one of said first and second membranes is substantially removed from the mandrel over a first portion of the at least one membrane and is substantially contacting the mandrel over a second portion of the at least one membrane, whereby: movement of the first membrane in the first direction progressively increases contact between the first membrane and the mandrel, and movement of the second membrane in the second direction progressively increases contact between the second membrane and the mandrel.