Printhead nozzle arrangement with a micro-electromechanical shape memory alloy based actuator

• US 7,192,119 B2
• Filed: 03/16/2005
• Issued: 03/20/2007
• 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): Do; An H.
• Application Number:
  US11/080,496
• Publication Number:
  US 20050157084A1
• Time in Patent Office: 734 Days
• Field of Search: 347/54, 347/56, 347/65
• 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

A printhead nozzle arrangement includes a substrate. Drive circuitry is positioned on the substrate. A nozzle chamber structure is arranged on the substrate and defines a nozzle chamber in fluid communication with a supply of ink and an ink ejection port in fluid communication with the nozzle chamber. An actuator is connected to the drive circuitry and is operatively positioned with respect to the nozzle chamber. The actuator is reciprocally deformable between a quiescent condition and an active condition to eject ink from the ink ejection port. At least a portion of the actuator is in the form of a shape memory alloy which is in a pre-stressed martensitic phase when the actuator is in the quiescent condition and in an austenitic phase when the actuator is in the active condition so that cyclic phase changes generate the reciprocal movement.

Claims

1. A printhead nozzle arrangement which comprises

a substrate;

drive circuitry positioned on the substrate;

a nozzle chamber structure arranged on the substrate, defining a nozzle chamber in fluid communication with a supply of ink and an ink ejection port in fluid communication with the nozzle chamber; and

an actuator that is connected to the drive circuitry and is operatively positioned with respect to the nozzle chamber, the actuator being reciprocally deformable between a quiescent condition and an active condition to eject ink from the ink ejection port,

wherein the actuator comprises a shape memory alloy sandwiched between a first structural layer and a second structural layer, the second structural layer being mechanically locked to the first structural layer to provide a stress reference for the first structural layer, and wherein the shape memory alloy is in a pre-stressed martensitic phase when the actuator is in the quiescent condition and in an austenitic phase when the actuator is in the active condition, such that cyclic phase changes generate said reciprocal movement.

2. A printhead nozzle arrangement as claimed in claim 1, in which the nozzle chamber structure is defined by an etched passage through the substrate, and an etch stop layer that defines the ink ejection port.

3. A printhead nozzle arrangement as claimed in claim 2, in which the substrate is of silicon, while the etch stop layer is a boron-doped epitaxial layer.

4. A printhead nozzle arrangement as claimed in claim 2, in which the actuator is positioned on the substrate, opposite the ink ejection port, the actuator being bent away from the ink ejection port in the quiescent condition and straightened towards the ink ejection port in the active condition.

5. A printhead nozzle arrangement as claimed in claim 4, in which the shape memory alloy defines a heating circuit of the actuator, the heating circuit having a substantially flat martensitic phase and being connected to the drive circuitry to receive an electrical heating signal from the drive circuitry, and a first structural layer that is positioned on the heating circuit, the first structural layer being the result of a high-temperature deposition so that, subsequent to cooling, the first structural layer and the heating circuit bent into the quiescent condition with the heating circuit in the martensitic phase.

6. A printhead nozzle arrangement as claimed in claim 1, in which the first structural layer is silicon nitride, the shape memory alloy is a nickel titanium alloy and the second structural layer is silicon oxide.