Ink printing apparatus using ink surfactants

• US 5,726,693 A
• Filed: 07/22/1996
• Issued: 03/10/1998
• Est. Priority Date: 07/22/1996
• Status: Expired due to Fees

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Clark, David Lee, Sharma, Ravi, Hawkins, Gilbert Allan, Bagchi, Pranab
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): Patel, Rajnikant B.
• Application Number:
  US08/681,233
• Time in Patent Office: 596 Days
• Field of Search: 347/54, 347/48, 347/55, 347/15, 347/44, 106/22, 106/266, 106/20 B, 428/411.1, 428/195, 523/161, 346/140 R
• US Class Current: 347/48
• 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 2/14451 Structure of ink jet print heads discharging by lowering surface tension of meniscus

Abstract

A liquid ink, drop-on-demand pagewidth printhead including a semiconductor substrate, a plurality of drop-emitter nozzles fabricated on the substrate; an ink supply manifold coupled to the nozzles; pressure element for subjecting ink in the manifold to a pressure above ambient pressure; a drop selection device for selectively addressing predetermined nozzles, and drop separation device to transfer ink selected drops from selected nozzles to a print region. A surface tension reducing agent for each nozzle is provided from a supply separate from the ink and integrated into the printhead. An increase in ink drop protrusion from the nozzle surface differentiates selected drops from non-selected drops.

Claims

1. An ink jet printhead for drop-on-demand printing, said printhead comprising:

(a) a substrate having a plurality of drop-emitter orifices;

(b) an ink channel coupled to each of said orifices for delivery of a body of ink to the orifices;

(c) pressure means for subjecting ink in said channels to a pressure above ambient pressure;

(d) a supply of surface tension reducing agent which is separate from the body of ink; and

(e) drop selection means for selectively delivering a surface tension reducing agent from said supply to ink which has been delivered to selectively addressed ones of the orifices, thereby causing a difference in meniscus position between ink in addressed and non-addressed orifices.

2. The printhead of claim 1 further including drop separating means for causing ink from addressed orifices to separate as drops from the body of ink while allowing ink to be retained in non-addressed orifices.

3. The printhead of claim 2 wherein:

said selection means causes ink in addressed orifices to move to selected positions, retained by surface tension, but further protruding from the orifices than ink in non-addressed orifices; and

said drop separating means attracts such further-protruding ink toward a print region.

4. The printhead of claim 1 in which said surface tension reducing agent is a chemical surfactant.

5. The printhead of claim 4 further including drop separating means for causing ink from addressed orifices to separate as drops from the body of ink while allowing ink to be retained in non-addressed orifices.

6. The printhead of claim 5 wherein:

said selection means causes ink in addressed orifices to move to selected positions, retained by surface tension, but further protruding from the orifices than ink in non-addressed orifices; and

said drop separating means attracts such further-protruding ink toward a print region.

7. The printhead of claim 4 in which said selection means is vapor deposition of surfactant onto the ink delivered to the orifices.

8. The printhead of claim 6 in which the vapor deposition of surfactant is provided by thermal vaporization of a liquid surfactant.

9. The printhead of claim 8 wherein:

the selection means comprises an electrical resistor; and

vaporization of the surfactant is produced by current flow through the resistor.

10. The printhead of claim 9 wherein:

the substrate is a silicon wafer; and

the current is provided by monolithically integrated circuits on the silicon wafer.

11. The printhead of claim 6 wherein the orifices are each formed of an extended nozzle aperture to confine the vapor.

12. The printhead of claim 8 in which vaporization of the surfactant is produced by current flow through the liquid surfactant to an integrally provided grid.

13. The printhead of claim 1 in which the ink is a pigmented ink.

14. The printhead of claim 1 in which the ink is a magnetic ink.

15. The printhead of claim 1 in which the ink is an emulsion ink.

16. The printhead of claim 1 in which the ink is a microemulsion ink.