ELECTROHYDRODYNAMIC JET PRINTING DEVICE WITH EXTRACTOR

• US 20140322451A1
• Filed: 04/28/2014
• Published: 10/30/2014
• Est. Priority Date: 04/26/2013
• Status: Active Grant

• Current Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Original Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Inventors: Barton, Kira, Leo, Tse Lai Yu
• Granted Patent: US 9,415,590 B2
• Time in Patent Office: Days
• US Class Current: 427/466
• CPC Class Codes: B05B 5/0255 spraying and depositing by electrostatic forces only
• CPC Class Codes: B05B 5/03 characterised by the use of gas , e.g. electrostatically assisted pneumatic spraying B05B5/04, B05B5/043, B05B5/047 take precedence
• CPC Class Codes: B05B 5/1608 the liquid or other fluent material being electrically conductive
• CPC Class Codes: B05C 5/00 Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work B05C7/00 takes precedence; essentially involving spraying or electrostatic projection B05B
• CPC Class Codes: B41J 2/06 by electric or magnetic field

Abstract

A printing device includes a nozzle and an extractor. An electrostatic extraction field is generated at the extractor and at a discharge opening of the nozzle to extract polarized ink from the nozzle for deposition on a printing substrate. The extractor includes an electrically conductive portion for application of one side of a voltage potential to generate the electrostatic field. The extractor can be in the form of an extractor plate with an opening through which the extracted ink passes, or the extractor can be in the form of another nozzle. The printing device provides a directionality field that affects the trajectory of the extracted ink. The directionality field can include the electrostatic field or a gas flow field. The printing device is useful for electrohydrodynamic jet, or e-jet, printing on a non-conductive substrate.

Claims

1. A printing device, comprising:

a nozzle having a discharge opening and being configured to provide polarized printing fluid at the discharge opening; and

an extractor that provides an electrostatic field at the discharge opening that extracts the polarized printing fluid from the nozzle through the discharge opening for deposition on a printing substrate in response to an applied voltage, wherein the nozzle and the extractor are configured to move together with respect to the printing substrate.

2. A printing device as defined in claim 1, wherein each of the nozzle and the extractor comprises an electrically conductive portion, the voltage being applied across said electrically conductive portions to provide the electrostatic field and to polarize the printing fluid.

3. A printing device as defined in claim 1, wherein the extractor comprises an electrically conductive layer having an opening formed therethrough and located so that extracted printing fluid passes through the opening in the electrically conductive layer for deposition on the printing substrate.

4. A printing device as defined in claim 1, wherein the extractor comprises first and second electrically conductive layers with coaxial openings formed through each of the electrically conductive layers, the voltage being applied across the first and second electrically conductive layers and the extractor being located so that extracted printing fluid passes through at least one of said coaxial openings for deposition on the printing substrate.

5. A printing device as defined in claim 4, wherein the voltage is additionally applied across the nozzle and one of the electrically conductive layers so that the nozzle is at the same potential as the other one of the electrically conductive layers.

6. A printing device as defined in claim 1, further comprising a directionality unit that provides, in addition to said electrostatic field, an electric field and/or a magnetic field between the nozzle and the printing substrate through which the extracted printing fluid travels for deposition on the printing substrate.

7. A printing device as defined in claim 1, further comprising a fluid flow passage and a gas discharge port arranged to discharge pressurized gas from the fluid flow passage in a direction toward the printing substrate to provide a gas flow field between the nozzle and the printing substrate in which the extracted printing fluid travels for deposition on the printing substrate.

8. A printing device as defined in claim 7, wherein the extractor comprises the gas discharge port.

9. A printing device as defined in claim 1, wherein the discharge opening lies along a longitudinal axis of the nozzle and the longitudinal axis is arranged at an obtuse angle with respect to a direction of travel of the printing fluid toward the printing substrate.

10. A printing device as defined in claim 1, wherein the nozzle and the extractor are arranged so that the electrostatic field extracts the polarized printing fluid from the nozzle in a direction different from a direction of travel of the printing fluid toward the printing substrate.

11. A printing device as defined in claim 1, wherein the extractor, the nozzle, or each of the extractor and the nozzle is rotatable about a rotational axis.

12. A printing device as defined in claim 1, wherein the location of the nozzle with respect to the extractor is adjustable in at least one direction.

13. A printing device as defined in claim 1 comprising a plurality of nozzles, each one of the nozzles having a discharge opening and being configured to provide polarized printing fluid at the discharge opening, wherein an electrostatic field is provided at each of the discharge openings that extracts the polarized printing fluid from each nozzle for deposition on the printing substrate in response to the applied voltage.

14. A printing device as defined in claim 13, wherein the extractor comprises an electrically conductive layer having a plurality of openings formed therethrough so that printing fluid from each one of the nozzles passes through a corresponding one of the openings in the electrically conductive layer for deposition on the printing substrate.

15. A printing device as defined in claim 14 configured to generate a directionality field between the discharge opening of each nozzle and the printing substrate that helps direct the extracted printing fluid toward the printing substrate.

16. A printing device as defined in claim 13, further comprising a shield extending between adjacent nozzles to help isolate the electrostatic fields at adjacent discharge openings.

17. A method of printing, comprising the steps of:

(a) applying a voltage across two components of a print head to generate an electrostatic extraction field between the two components sufficient to extract polarized printing fluid from a nozzle of the print head; and

(b) providing a directionality field to propel the extracted printing fluid toward a printing substrate.

18. The method of claim 17, wherein the printing substrate is non-conductive, contoured, flexible, or any combination thereof.

19. The method of claim 17, wherein the directionality field comprises a gas flow field, the electrostatic field, an additional electric field, a magnetic field, or any combination thereof.

20. A printing device, comprising:

a first nozzle having a discharge opening and being configured to provide polarized printing fluid at the discharge opening; and

a second nozzle having a gas discharge port in fluid communication with a pressurized fluid flow passage to provide a gas flow field at the gas discharge port, wherein the nozzles are arranged to provide an electrostatic field at the discharge opening that extracts the polarized printing fluid from the first nozzle and into the gas flow field for deposition on a printing substrate when a voltage potential is applied across the nozzles.