Micromachined fluid ejector systems and methods

• US 6,367,915 B1
• Filed: 11/28/2000
• Issued: 04/09/2002
• Est. Priority Date: 11/28/2000
• Status: Expired due to Term

• Current Assignee: National Technology & Engineering Solutions Of Sandia LLC (Honeywell International Inc.), 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:
  US09/722,331
• Time in Patent Office: 497 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, 310/328-338
• US Class Current: 347/54
• CPC Class Codes: B41J 2/14314 Structure of ink jet print heads with electrostatically actuated membrane

Abstract

An electrostatic microelectromechanical system (MEMS) based fluid ejector comprises a movable piston structure and a stationary faceplate. A fluid chamber is defined between the piston structure and a substrate. The piston structure 110 may be resiliently mounted on the substrate by one or more spring elements. A fluid to be ejected is supplied in the fluid chamber from a fluid reservoir through a fluid refill hole formed in the substrate. The faceplate includes a nozzle hole through which a fluid jet or drop is ejected. In various exemplary embodiments, the piston structure moves towards the faceplate by electrostatic attraction between the piston structure and the faceplate. As a result of the movement of the piston structure, a portion of the fluid between the piston structure and the faceplate is forced out of the nozzle hole, forming a jet or drop of the fluid.

Claims

1. A microelectromechanical system-based fluid ejector, comprising:

a movable piston structure having a working surface with an outer edge, the piston structure being movable in a direction substantially perpendicular to the working surface; and

a fluid chamber defined within the fluid ejector such that a fluid in the fluid chamber flows freely in a direction transverse to the working surface in a region adjacent the outer edge of the working surface.

2. The fluid ejector of claim 1, further comprising:

a faceplate having a nozzle hole through which a drop of the fluid in the fluid chamber is to be ejected;

a substrate disposed opposite the faceplate, the piston structure being situated between the substrate and the faceplate; and

a fluid refill hole formed through the substrate to supply the fluid to the fluid chamber.

3. The fluid ejector of claim 2, wherein the piston structure is situated between the substrate and the faceplate aligned with the fluid refill hole.

4. The fluid ejector of claim 1, further comprising:

a faceplate having a nozzle hole through which a drop of the fluid in the fluid chamber is to be ejected;

a substrate disposed opposite the faceplate, the piston structure being situated between the substrate and the faceplate; and

a counter-electrode associated with the substrate.

5. The fluid ejector of claim 4, wherein the piston structure is situated between the substrate and the faceplate aligned with the counter-electrode.

6. The fluid ejector of claim 4, further comprising a fluid refill hole formed through the substrate to supply the fluid to the fluid chamber, wherein the counter-electrode is disposed substantially around a periphery of the fluid refill hole.

7. The fluid ejector of claim 6, wherein the piston structure is situated between the substrate and the faceplate aligned with the fluid refill hole.

8. The fluid ejector of claim 6, wherein the counter-electrode comprises an annular counter-electrode.

9. The fluid ejector of claim 4, further comprising a fluid refill hole formed through the substrate to supply the fluid to the fluid chamber, wherein the counter-electrode comprises a filter and is situated over the fluid refill hole.

10. The fluid ejector of claim 4, further comprising a fluid refill hole formed through the substrate to supply the fluid to the fluid chamber, wherein the counter-electrode comprises a filter and is situated within the fluid refill hole.

11. A microelectromechanical system-based fluid ejector, comprising:

a fluid chamber defined within the fluid ejector; and

a movable piston structure disposed within the fluid chamber without a corresponding cylinder structure, such that a fluid in the fluid chamber flows freely in a direction transverse to a working surface of the piston structure in a region adjacent an outer edge of the working surface.

12. The fluid ejector of claim 11, further comprising:

a faceplate having a nozzle hole through which a drop of the fluid in the fluid chamber is to be ejected;

a substrate disposed opposite the faceplate, the piston structure being situated between the substrate and the faceplate; and

a fluid refill hole formed through the substrate to supply the fluid to the fluid chamber.

13. The fluid ejector of claim 12, wherein the piston structure is situated between the substrate and the faceplate aligned with the fluid refill hole.

14. The fluid ejector of claim 11, further comprising:

a faceplate having a nozzle hole through which a drop of the fluid in the fluid chamber is to be ejected;

a substrate disposed opposite the faceplate, the piston structure being situated between the substrate and the faceplate; and

a counter-electrode associated with the substrate.

15. The fluid ejector of claim 14, wherein the piston structure is situated between the substrate and the faceplate aligned with the counter-electrode.

16. The fluid ejector of claim 14, further comprising a fluid refill hole formed through the substrate to supply the fluid to the fluid chamber, wherein the counter-electrode is disposed substantially around a periphery of the fluid refill hole.

17. The fluid ejector of claim 16, wherein the piston structure is situated between the substrate and the faceplate aligned with the fluid refill hole.

18. The fluid ejector of claim 16, wherein the counter-electrode comprises an annular counter-electrode.

19. The fluid ejector of claim 14, further comprising a fluid refill hole formed through the substrate to supply the fluid to the fluid chamber, wherein the counter-electrode comprises a filter and is situated over the fluid refill hole.

20. The fluid ejector of claim 14, further comprising a fluid refill hole formed through the substrate to supply the fluid to the fluid chamber, wherein the counter-electrode comprises a filter and is situated within the fluid refill hole.

21. A method of ejecting a fluid using a microelectromechanical system-based fluid ejector having a movable piston structure disposed in a fluid chamber between a substrate and a faceplate having a nozzle hole, comprising:

moving a movable piston structure within a fluid chamber such that a fluid in the fluid chamber flows in a direction transverse to a working surface of the piston structure; and

ejecting a drop of the fluid through a nozzle hole in a faceplate substantially by viscous fluid flow forces between the working surface of the piston structure and a stationary structure of the fluid ejector associated with moving the piston structure.

22. The method of claim 21, further comprising refilling the fluid in the fluid chamber through a fluid refill hole formed through the substrate.

23. The method of claim 22, further comprising actively moving the movable piston structure towards an at-rest position.

24. The method of claim 22, further comprising filtering the fluid prior to refilling the fluid in the fluid chamber.