Planar thermoelastic bend actuator ink jet printing mechanism

• US 6,213,589 B1
• Filed: 07/10/1998
• Issued: 04/10/2001
• Est. Priority Date: 07/15/1997
• Status: Expired due to Fees

• Current Assignee: Zamtec Limited (Memjet Limited)
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Silverbrook, Kia
• Primary Examiner(s): Barlow, John
• Assistant Examiner(s): Do, An H.
• Application Number:
  US09/112,802
• Time in Patent Office: 1,005 Days
• Field of Search: 347/44, 347/54, 347/62, 347/55, 347/20, 347/47
• US Class Current: 347/54
• CPC Class Codes: B41J 2/14427 Structure of ink jet print heads with thermal bend detached actuators
• 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 2/1632 machining
• CPC Class Codes: B41J 2/1639 sacrificial molding
• CPC Class Codes: B41J 2/1642 thin film formation by CVD [chemical vapor deposition]
• CPC Class Codes: B41J 2/1643 thin film formation by plating
• CPC Class Codes: B41J 2/1645 thin film formation by spincoating
• CPC Class Codes: B41J 2/1646 thin film formation by sputtering
• CPC Class Codes: B41J 2/1648 Production of print heads with thermal bend detached actuators
• CPC Class Codes: B41J 2/16585 for paper-width or non-reciprocating print heads
• CPC Class Codes: B41J 2/17596 Ink pumps, ink valves
• CPC Class Codes: B41J 2002/041 Electromagnetic transducer
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: G06K 1/121 by printing code marks applying code marks to labels B65C9/46; marking or coding completed packages B65B61/26
• CPC Class Codes: G06K 19/06037 multi-dimensional coding
• CPC Class Codes: G06K 7/14 using light without selection of wavelength, e.g. sensing reflected white light G06K7/10831 - G06K7/1097 take precedence
• CPC Class Codes: G06K 7/1417 2D bar codes
• CPC Class Codes: G11C 11/56 using storage elements with more than two stable states represented by steps, e.g. of voltage, current, phase, frequency
• CPC Class Codes: H04N 23/00 : Cameras or camera modules comprising electronic image sensors; Control thereof
• CPC Class Codes: H04N 5/2628 : Alteration of picture size, shape, position or orientation, e.g. zooming, rotation, rolling, perspective, translation

Abstract

This patent describes a new form of ink jet printer which a planar thermoelastic bend actuator to eject ink from a nozzle chamber. The thermal actuator includes a lower planar surface constructed from a highly conductive material such as a semiconductor metal layer interconnected to an upper planar material constructed from an electrically resistive material such as Indium Tin Oxide (ITO), such that, upon passing a current between the planar surfaces, the thermal actuator is caused to bend towards the ink ejection port so as to thereby cause the ejection of ink from the ink ejection port. The actuator is attached to a substrate and further includes a stiff paddle portion which increases the degree of bending of the actuator near the point where it is attached to the substrate. Surfaces are further coated with a passivation material as required.

Claims

1. An ink jet printhead comprising:

a nozzle chamber having an ink ejection port in one wall of said chamber;

an ink supply source interconnected to said nozzle chamber; and

a thermal actuator activated to eject ink from said nozzle chamber via said ink ejection port, said thermal actuator comprising a lower planar surface constructed from a highly electrically conductive material interconnected to an upper planar material constructed from an electrically resistive material such that upon passing a current between said planar surfaces, said thermal actuator is caused to bend towards said ink ejection port so as to thereby cause to be ejected ink from said ink ejection port.

2. An ink jet printhead as claimed in claim 1 wherein said actuator is attached to a substrate and further includes a stiff paddle portion which increases bending of said actuator near the point where it is attached to the substrate.

3. An ink jet printhead as claimed in claim 2 wherein said stiff paddle is formed of silicon nitride.

4. An ink jet printhead as claimed in claim 1 wherein said actuator further includes an expansion coating having a high coefficient of thermal expansion on top of said upper planar surface so as to increase bending of said actuator.

5. An ink jet printhead as claimed in claim 4 wherein said expansion coating comprises substantially polytetrafluoroethylene.

6. An ink jet printhead as claimed in claim 1 wherein between said upper planar surface and said lower planar surface there is provided a gap, constructed through utilization of a sacrificial material which is deposited and subsequently etched away so as to leave said gap.

7. An ink jet printhead as claimed in claim 6 wherein said upper planar surface includes a plurality of etchant holes provided so as to allow a more rapid etching of said sacrificial layer during construction.

8. An ink jet printhead as claimed in claim 1 wherein said upper planar surface comprises substantially Indium Tin Oxide (ITO).

9. An ink jet printhead as claimed in claim 1 wherein said lower planar surface comprises substantially a metal layer.

10. An ink jet nozzle as claimed in claim 1 wherein said surfaces are further coated with a passivation material as required.

11. An ink jet printhead as claimed in claim 1 wherein said ink jet printhead is formed on a silicon wafer utilising micro-electro mechanical systems construction techniques.