Shape memory alloy ink jet printing mechanism

• US 6,557,977 B1
• Filed: 07/10/1998
• Issued: 05/06/2003
• Est. Priority Date: 07/15/1997
• Status: Expired due to Fees

• Current Assignee: Memjet Technology Ltd. (Memjet Limited)
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Silverbrook, Kia
• Primary Examiner(s): Gordon, Raquel Yvette
• Assistant Examiner(s): Do, An H.
• Application Number:
  US09/113,122
• Time in Patent Office: 1,761 Days
• Field of Search: 347/20, 347/44, 347/53, 347/54, 347/84, 347/85, 347/55, 347/47, 347/151, 347/120, 347/141, 347/154, 347/103, 347/123, 347/111, 347/68-72, 347/63, 347/40, 399/261, 310/328-330, 298/901
• US Class Current: 347/54
• CPC Class Codes: B41J 2/14 Structure thereof only for on-demand ink jet heads
• CPC Class Codes: B41J 2/14314 Structure of ink jet print heads with electrostatically actuated membrane
• CPC Class Codes: B41J 2/14427 Structure of ink jet print heads with thermal bend detached actuators
• CPC Class Codes: B41J 2/16 Production of nozzles
• CPC Class Codes: B41J 2/1623 bonding and adhesion
• CPC Class Codes: B41J 2/1626 etching
• 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 2/1635 dividing the wafer into individual chips
• CPC Class Codes: B41J 2/1637 molding
• 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 2/17513 Inner structure
• CPC Class Codes: B41J 2/17596 : Ink pumps, ink valves
• CPC Class Codes: B41J 2002/041 : Electromagnetic transducer
• CPC Class Codes: B41J 2002/14346 : Ejection by pressure produced by thermal deformation of ink chamber, e.g. buckling
• CPC Class Codes: B41J 2002/14435 : Moving nozzle made of thermal bend detached actuator
• CPC Class Codes: B41J 2002/14443 : Nozzle guard
• CPC Class Codes: B41J 2202/21 : Line printing
• CPC Class Codes: G06F 21/79 : in semiconductor storage media, e.g. directly-addressable memories
• CPC Class Codes: G06F 21/86 : Secure or tamper-resistant housings
• CPC Class Codes: G06F 2221/2129 : Authenticate client device independently of the user
• 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: G07F 7/08 : by coded identity card or credit card or other personal identification means without personal verification means G07F7/02
• CPC Class Codes: G07F 7/086 : by passive credit-cards adapted therefor, e.g. constructive particularities to avoid counterfeiting, e.g. by inclusion of a physical or chemical security-layer for security documents G07D7/00; for the reading of record-carriers in general G06K7/00; for the design of coded credit-cards G06K19/10
• CPC Class Codes: G07F 7/12 : Card verification
• 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
• CPC Class Codes: Y10T 29/49083 : Heater type
• CPC Class Codes: Y10T 29/49117 : Conductor or circuit manufacturing
• CPC Class Codes: Y10T 29/49128 : Assembling formed circuit to base
• CPC Class Codes: Y10T 29/49169 : Assembling electrical component directly to terminal or elongated conductor
• CPC Class Codes: Y10T 29/49172 : by molding of insulating material
• CPC Class Codes: Y10T 29/49401 : Fluid pattern dispersing device making, e.g., ink jet

Abstract

This patent describes ink jet printing device that utilizes a shape memory alloy such as a nickel titanium alloy for ejecting drops. The ejection involves utilization of the transformation of a shape memory alloy from its martensitic phase to its austenitic phase (or vice versa) as an actuator to cause the ejection of ink from chamber. The actuator is normally in its quiescent state and transfers to an ink injection state upon heating thereby causing ink ejection from the chamber. The heating occurs by passing a current through the shape memory alloy. The shape memory alloy can be conductive and arranged in a serpentine form for operation. The actuator being formed above a crystallographically etched nozzle chamber having a nozzle port from which ink is ejected.

Claims

1. An ink jet print head chip that comprises

a wafer substrate;

a drive circuitry layer positioned on the wafer substrate; and

a plurality of micro-elecromechanical nozzles positioned on the wafer substrate, each nozzle comprising

a nozzle chamber defined by the wafer substrate, the nozzle chamber being in fluid communication with an ink supply; and

an actuator that is positioned in the nozzle chamber, the actuator being displaceable between a quiescent position and an operative position with respect to the wafer substrate to eject ink from the nozzle chamber, the actuator being connected to the drive circuitry layer and at least part of the actuator being of a shape memory alloy that is capable of being heated on receipt of an electrical signal from the drive circuitry layer such that the shape memory alloy undergoes a thermal transition to displace the actuator from the quiescent position to the operative position.

2. An ink jet print head as claimed in claim 1, in which the shape memory alloy is in the form of a metal that relies on a thermal transition from a martensitic phase to an austenitic phase.

3. An ink jet print head chip as claimed in claim 1, in which each nozzle chamber is the result of an etching process carried out on the wafer substrate, with the wafer substrate also defining a nozzle opening, from which the ink can be ejected, in fluid communication with each nozzle chamber.

4. An ink jet print head chip as claimed in claim 3, in which each actuator is in the form of a bend actuator, with one end of the bend actuator being mechanically connected to the wafer substrate and an opposite end being free to move with respect to the wafer substrate.

5. An ink jet print head as claimed in claim 4, in which each bend actuator includes a heating circuit of the shape memory alloy electrically connected to the drive circuitry layer, the heating circuit being fast with a pre-stressing layer of resiliently flexible material so that the heating circuit and the pre-stressing layer are bent away from the nozzle opening when the shape memory alloy is in a pre-thermal transition phase, such that when the electrical signal heats the shape memory alloy to undergo thermal transition, the shape memory alloy straightens the bend actuator towards the nozzle opening to eject ink from the nozzle opening.