Micro-electromechanical fluid ejecting device that incorporates a covering formation for a micro-electromechanical actuator

• US 6,948,799 B2
• Filed: 10/13/2004
• Issued: 09/27/2005
• 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): Gordon, Raquel Yvette
• Application Number:
  US10/962,394
• Publication Number:
  US 20050083376A1
• Time in Patent Office: 349 Days
• Field of Search: 347/54, 347/68, 347/69, 347/70, 347/71, 347/72, 347/50, 347/40, 347/20, 347/44, 347/47, 347/27, 347/63, 399/261, 361/700, 310328-330, 298/901
• 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 2/1601 Production of bubble jet print heads B41J2/1606, B41J2/162 take precedence
• 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 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: 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

A micro-electromechanical fluid ejection device includes a substrate that incorporates drive circuitry and defines a fluid inlet channel. A nozzle chamber structure is positioned on the substrate and defines a nozzle chamber in fluid communication with the fluid inlet channel and a fluid ejection port in fluid communication with the nozzle chamber. A micro-electromechanical actuator is positioned on the substrate and is electrically connected to the drive circuitry to be displaced relative to the substrate on receipt of an electrical current from the drive circuitry. A fluid ejecting member is positioned in the nozzle chamber and is connected to the actuator to eject fluid from the ink ejection port on displacement of the actuator. A covering formation is positioned on the substrate and is configured to enclose the micro-electromechanical actuator.

Claims

1. A micro-electromechanical fluid ejection device that comprises

a substrate that incorporates drive circuitry and defines a fluid inlet channel;

a nozzle chamber structure that is positioned on the substrate and defines a nozzle chamber in fluid communication with the fluid inlet channel and a fluid ejection port in fluid communication with the nozzle chamber;

a micro-electromechanical actuator that is positioned on the substrate and is electrically connected to the drive circuitry to be displaced relative to the substrate on receipt of an electrical current from the drive circuitry;

a fluid ejecting member that is positioned in the nozzle chamber and is connected to the actuator to eject fluid from the ink ejection port on displacement of the actuator; and

a covering formation that is positioned on the substrate and is configured to enclose the micro-electromechanical actuator.

2. A micro-electromechanical fluid ejection device as claimed in claim 1, in which the covering formation includes sidewalls that extend from the substrate and a roof wall that spans the substrate.

3. A micro-electromechanical fluid ejection device as claimed in claim 2, in which the actuator is elongate and has a fixed end that is connected to the substrate so that the actuator can receive an electrical signal from the drive circuitry and a movable end, the actuator being configured so that the movable end is displaced relative to the substrate on receipt of the electrical signal.

4. A micro-electromechanical fluid ejection device as claimed in claim 3, in which a motion-transmitting structure is fast with the movable end of the actuator, the motion-transmitting structure being connected to the fluid ejecting member so that movement of the actuator is translated to the fluid ejecting member, the motion-transmitting structure defining part of the roof wall and spaced from a remaining part of the roof wall to allow for movement of the motion-transmitting structure.

5. A micro-electromechanical fluid ejection device as claimed in claim 4, in which the roof wall defines a cover that spans the walls to cover the elongate actuator, the motion-transmitting structure being shaped so that the cover and the motion-transmitting structure define generally co-planar surfaces that are spaced from, and generally parallel to the substrate, an opening being defined between the cover and the motion-transmitting surface to facilitate relative displacement of the cover and the motion-transmitting surface.

6. A micro-electromechanical fluid ejection device as claimed in claim 4, in which the motion-transmitting structure defines a lever mechanism and has a fulcrum formation that is fast with the substrate and pivotal with respect to the substrate and a lever arm formation mounted on the fulcrum formation, an effort formation being connected between the movable end of the actuator and the lever arm formation and a load formation being connected between the lever arm formation and the fluid ejecting member.

7. A micro-electromechanical fluid ejection device as claimed in claim 6, in which the lever arm formation, the cover and the walls define a unitary structure with the lever arm formation being connected to the walls with a pair of opposed torsion formations that are configured to twist as the lever formation is displaced.

8. A micro-electromechanical fluid ejection device as claimed in claim 3, in which the actuator includes at least one elongate actuator arm of a conductive material that is capable of thermal expansion to perform work, the actuator arm having an active portion that defines a heating circuit that is connected to the drive circuitry layer to be resistively heated on receipt of the electrical signal from the drive circuitry layer and subsequently cooled on termination of the signal, and a passive portion which is insulated from the drive circuitry layer, the active and passive portions being positioned with respect to each other so that the arm experiences differential thermal expansion and contraction reciprocally to displace the movable end of the actuator.