Patent ID: 6626520
Filing Date: 2003-09-30
Classification: B41J

Abstract:
An emission device for ejecting a liquid drop, said device comprising:a structure defining a chamber volume adapted to receive a liquid and having a nozzle orifice through which a drop of received liquid can be emitted; a first electrode associated with a movable wall portion of the chamber volume defining structure such that movement of the first electrode in a first direction moves the movable wall portion to increase the chamber volume to draw liquid into the chamber volume; a second electrode associated with the movable wall portion such that movement of the second electrode in a second direction moves the movable wall portion to decrease the chamber volume to emit a liquid drop through the nozzle orifice; and a third electrode between the first and second electrodes such that (1) application of an electrostatic charge differential between the first electrode and the third electrode moves the first electrode in said first direction to increase the chamber volume and (2) application of an electrostatic charge differential between the second electrode and the third electrode moves the second electrode in said second direction to decrease the chamber volume, said third electrode having opposed surfaces respectively facing each of said first and second electrodes, wherein: one of said opposed surfaces of the third electrode faces one of said first and second electrodes at an angle of contact whereby movement of said one of said first and second electrodes toward the third electrode progressively increases contact between said one of said first and second electrodes and said one of said opposed surfaces of the third electrode, and the other of said opposed surfaces of the third electrode is flat.