Method and apparatus for promoting the complete transfer of liquid drops from a nozzle

• US 7,458,661 B2
• Filed: 01/23/2006
• Issued: 12/02/2008
• Est. Priority Date: 01/25/2005
• Status: Active Grant

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Kim, Chang-Jin, Yi, Uichong Brandon
• Primary Examiner(s): JACKSON, JUANITA DIONNE
• Application Number:
  US11/275,668
• Publication Number:
  US 20060164490A1
• Time in Patent Office: 1,044 Days
• Field of Search: 347/20, 347 44- 47, 347/55, 347/56, 347 61- 65, 347/67, 347/103, 347/348
• US Class Current: 347/47
• CPC Class Codes: B41J 2/005 characterised by bringing liquid or particles selectively into contact with a printing material printing by selective application of impact or pressure on a printing or impression-transfer material B41J2/22
• CPC Class Codes: B41J 2/14 Structure thereof only for on-demand ink jet heads
• CPC Class Codes: B41J 2/16 Production of nozzles
• CPC Class Codes: B41J 2/1628 dry etching
• CPC Class Codes: B41J 2/1629 wet etching
• CPC Class Codes: B41J 2/1631 photolithography
• CPC Class Codes: B41J 2/1642 thin film formation by CVD [chemical vapor deposition]
• CPC Class Codes: B41J 2/1645 thin film formation by spincoating
• CPC Class Codes: B41J 2002/14395 Electrowetting
• CPC Class Codes: B41J 2002/14475 characterised by nozzle shapes or number of orifices per chamber

Abstract

A printhead device for transferring liquid droplets from a nozzle includes a liquid source coupled to a nozzle via a microchannel. The nozzle is formed from an orifice having an inner circumferential surface, wherein at least a portion of the inner circumferential surface is serrated. Liquid droplets are transported from the source to the nozzle using a liquid droplet driver (e.g., employing a plurality of driving electrodes). Transfer of droplets to another surface can be accomplished by contacting a bulging droplet in the nozzle with a printing surface. The surface and/or nozzle are then moved relative to one another to effectuate complete transfer of the liquid drop from the nozzle.

Claims

1. A device for transferring liquid droplets comprising:

a nozzle having an orifice with an inner circumferential surface, wherein at least a portion of the inner circumferential surface is serrated;

a liquid source and a passageway connecting the liquid source to the nozzle; and

a plurality of driving electrodes disposed in the passageway.

2. The device of claim 1, wherein at least half of the inner circumferential surface is serrated.

3. The device of claim 1, wherein the entire inner circumferential surface is serrated.

4. The device of claim 1, wherein the inner circumferential surface is coated with a non-wetting material.

5. The device of claim 1, wherein the serrated portion of the inner circumferential surface comprises a plurality of radially-oriented projections.

6. The device of claim 5, wherein the plurality of radially-oriented projections has geometric shape selected from the group consisting of rectangular, square, triangular, and sinusoidal.

7. The device of claim 1, wherein the passageway comprises a microchannel.

8. The device of claim 7, wherein the microchannel has a height that is less than the nominal diameter of the nozzle.

9. The device of claim 1, wherein the device includes a plurality of nozzles.

10. The device of claim 1, wherein the serrated inner circumferential surface comprises a roughened surface.

11. A device for transferring liquid droplets comprising:

a substrate;

a plurality of liquid sources disposed in the substrate, each source being coupled to at least one microchannel contained in the substrate and each microchannel being further coupled to a nozzle, wherein each nozzle comprises a substantially circular orifice having an inner circumferential surface, wherein at least a portion of the inner circumferential surface is serrated; and

a plurality of driving electrodes disposed along at least a portion of each microchannel for transporting fluid from the sources to the nozzles.

12. The device of claim 11, wherein the height of each microchannel is less than the diameter of the coupled nozzle.

13. The device of claim 11, wherein the liquid droplets contain biological material.

14. A method of transferring liquid droplets to a surface comprising:

providing a printhead for transferring liquid droplets to a surface, the printhead comprising;

a liquid source;

a nozzle in fluid communication with the liquid source, the nozzle comprising a substantially circular orifice having an inner circumferential surface, wherein at least a portion of the inner circumferential surface is serrated; and

a liquid droplet driver for transporting fluid from the liquid source to the nozzle, the liquid droplet driver comprising a plurality of driving electrodes;

providing the liquid source with a liquid;

providing the surface adjacent to the nozzle;

transporting one or more droplets from the liquid source to the nozzle such that at least a portion of the one or more droplets bulges outwardly toward the surface;

contacting the droplet with the surface; and

moving the surface away from the nozzle.

15. The method of claim 14, wherein the liquid contains biological material.

16. The method of claim 14, wherein after the droplet contacts the surface, the surface is moved away from a stationary nozzle.

17. The method of claim 14, wherein after the droplet contacts the surface, the nozzle is moved away from a stationary surface.

18. A system for transferring liquid droplets comprising:

a nozzle having an orifice with an inner circumferential surface, wherein at least a portion of the inner circumferential surface is serrated, the inner circumferential surface being a non-wetting surface; and

a printing surface comprising a wetting surface configured to receive liquid droplets from the nozzle.

19. The system of claim 18, wherein the non-wetting surface comprises a hydrophobic coating disposed on the inner circumferential surface of the orifice.

20. The system of claim 18, wherein the nozzle is configured to move relative the printing surface.

21. The system of claim 18, wherein the printing surface is configured to move relative to the nozzle.

22. The system of claim 18, wherein a liquid droplet is completely transferred from the nozzle to the printing surface leaving no residue at the nozzle.

23. The system of claim 18, wherein the liquid droplet contains biological material.

24. The system of claim 18, further comprising a channel fluidly coupled to the nozzle, the channel including at least one driving electrode configured to move a droplet within the channel.