Bi-directional fluid ejection systems and methods

• US 6,409,311 B1
• Filed: 11/24/2000
• Issued: 06/25/2002
• Est. Priority Date: 11/24/2000
• Status: Expired due to Term

• Current Assignee: Sandia Corporation (Martin Marietta Corporation), Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Crowley, Joseph M., Galambos, Paul C., Gooray, Arthur M., Givler, Richard C., Peter, Frank J., Roller, George J., Zavadil, Kevin R.
• Primary Examiner(s): Gordon, Raquel Yvette
• Application Number:
  US09/718,476
• Time in Patent Office: 578 Days
• Field of Search: 347/54, 347/68, 347/69, 347/70, 347/71, 347/72, 347/50, 347/40, 347/20, 347/44, 347/47, 347/27, 347/63, 399/261, 361/700, 310/328-330, 298/901
• US Class Current: 347/54
• CPC Class Codes: B41J 2/14314 Structure of ink jet print heads with electrostatically actuated membrane

Abstract

A bi-directional fluid ejector according to the systems and methods of this invention operates on the principle of electrostatic attraction. In various exemplary embodiments, the fluid ejector includes a sealed dual diaphragm arrangement, an electrode arrangement that is parallel and opposite to the sealed diaphragms, and a structure which contains the fluid to be ejected. A diaphragm chamber containing a relatively incompressible fluid is situated behind, and is sealed by, the diaphragms. At least one nozzle hole is formed in a faceplate of the ejector over one of the diaphragms. A drive signal is applied to at least one electrode of the electrode arrangement to generate an electrostatic field between the electrode and a first one of the diaphragms. The first diaphragm is attracted towards the electrode by an electrostatic force into a deformed shape due to the electrostatic field. Upon deforming, pressure is transmitted to a second one of the sealed diaphragms. The transmitted pressure and the relatively incompressible nature of the fluid contained within the sealed diaphragm chamber causes the second diaphragm to deflect in the opposite direction to force fluid through at least one of the at least one nozzle hole. After a drop is ejected, the movement is reversed, either through normal resilient restoration actions of the deformed diaphragm and/or through an applied force.

Claims

1. A method for ejecting a fluid from a fluid ejector, comprising:

generating a first electrostatic force that moves a first diaphragm of a dual diaphragm arrangement of a fluid ejector in a first direction; and

ejecting fluid from the fluid ejector by moving a second diaphragm in a second direction opposite the first direction in response to movement of the first diaphragm in the first direction.

2. The method of claim 1, further comprising:

replenishing a supply of fluid adjacent the second diaphragm by removing the first electrostatic force and generating a second electrostatic force that moves the second diaphragm in the first direction at least to a rest position.

3. The method of claim 2, wherein removing the first electrostatic force comprises removing the first electrostatic force sufficiently rapidly that the first and second diaphragms move past the rest position and fluid is ejected by moving the first diaphragm in the second direction.

4. The method of claim 1, further comprising:

replenishing a supply of fluid adjacent the second diaphragm by removing the first electrostatic force such that the first and second diaphragms resiliently move to a rest position.

5. The method of claim 1, further comprising:

generating a second electrostatic force that moves the second diaphragm in the first direction; and

ejecting fluid from the fluid ejector by moving the first diaphragm in the second direction in response to movement of the second diaphragm in the first direction.

6. The method of claim 5, further comprising:

replenishing a supply of fluid adjacent the second diaphragm by moving the first diaphragm in the second direction; and

replenishing a supply of fluid adjacent the first diaphragm by moving the second diaphragm in the second direction.

7. A bi-directional fluid ejection system, comprising:

a sealed dual diaphragm arrangement including;

a first diaphragm portion;

a second diaphragm portion; and

a diaphragm chamber defined at least partially by the first and second diaphragm portions;

a first electrode opposite the first diaphragm portion; and

a first nozzle hole located over the second diaphragm portion.

8. The system of claim 7, further comprising:

at least one support post that provides a support point for deflection of the first and second diaphragm portions.

9. The system of claim 7, further comprising:

an incompressible dielectric fluid contained in the diaphragm chamber.

10. The system of claim 9, wherein the dielectric fluid is a high performance dielectric fluid.

11. The system of claim 10, wherein the dielectric fluid is at least one of distilled water, an S-fluid, a T-fluid, an oil and an organic solution.

12. The system of claim 7, further comprising a second nozzle hole located over the first diaphragm.

13. The system of claim 12, further comprising a second nozzle hole located over the first diaphragm.

14. The system of claim 7, further comprising a second electrode opposite the second diaphragm.