Inkjet printhead chip with volume-reduction actuation

• US 7,156,494 B2
• Filed: 12/02/2004
• Issued: 01/02/2007
• Est. Priority Date: 06/09/1998
• Status: Expired due to Fees

• Current Assignee: Memjet Technology Ltd. (Memjet Limited)
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Silverbrook, Kia, McAvoy, Gregory John
• Primary Examiner(s): Do; An H.
• Application Number:
  US11/000,936
• Publication Number:
  US 20050078150A1
• Time in Patent Office: 761 Days
• Field of Search: 347/54, 347/56, 347/61, 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 2/1433 Structure of nozzle plates
• 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 2/1628 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 2/1648 Production of print heads with thermal bend detached actuators
• 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 2002/14475 characterised by nozzle shapes or number of orifices per chamber
• CPC Class Codes: B41J 2202/15 Moving nozzle or nozzle plate
• CPC Class Codes: Y10T 29/49128 : Assembling formed circuit to base
• CPC Class Codes: Y10T 29/4913 : Assembling to base an electrical component, e.g., capacitor, etc.
• CPC Class Codes: Y10T 29/49155 : Manufacturing circuit on or in base
• CPC Class Codes: Y10T 29/49156 : with selective destruction of conductive paths
• CPC Class Codes: Y10T 29/49401 : Fluid pattern dispersing device making, e.g., ink jet

Abstract

An inkjet printhead chip includes a wafer substrate. A drive circuitry layer is positioned on the wafer substrate. A plurality of nozzle chambers is defined in the wafer substrate. A plurality of ink inlet openings is defined in the wafer substrate, in fluid communication with respective nozzle chambers. A plurality of nozzle chamber walls is opposite respective ink inlet openings and each defines an ink ejection port. A plurality of ink ejection actuators is connected to the drive circuitry layer. At least one actuator is positioned in each wall and is displaceable into the respective nozzle chamber to reduce a volume of the nozzle chamber and thus to eject ink from the nozzle chamber.

Claims

1. An inkjet printhead chip which comprises

a wafer substrate;

a drive circuitry layer positioned on the wafer substrate;

a plurality of nozzle chambers defined in the wafer substrate;

a plurality of ink inlet openings defined in the wafer substrate, in fluid communication with respective nozzle chambers;

a plurality of nozzle chamber walls opposite respective ink inlet openings and each defining an ink ejection port; and

a plurality of ink ejection actuators connected to the drive circuitiy layer, at least one actuator being positioned in each wall and being displaceable into the respective nozzle chamber to reduce a volume of the nozzle chamber and thus to eject ink from the nozzle chamber;

each ink ejection actuator having an actuator arm of a material that has a coefficient of thermal expansion which is such that expansion of the actuator arm can be used to perform work and a heating circuit positioned in the actuator arm such that, when the arm is heated, the arm experiences thermal differential expansion and is thus displaced into the nozzle chamber.

2. An inkjet printhead chip as claimed in claim 1, in which each nozzle chamber is the result of a crystallographic etch carried out on the wafer such that each nozzle chamber is frustoconical and tapers inwardly towards the ink inlet opening.

3. An inkjet printhead chip as claimed in claim 2,which includes a number of ink ejection actuators positioned in each wall, the wall including a nozzle rim that defines the ink ejection port and the ink ejection actuators of each wall extending radially towards the nozzle rim.

4. An inkjet printhead chip as claimed in claim 3, in which an end of each actuator arm proximate the respective nozzle rim is displaceable into the nozzle chamber while an opposite end is fixed to the substrate.

5. An inkjet printhead chip as claimed in claim 3, in which each heater element is in the form of a serpentine electrical heating element to facilitate substantially unhindered expansion of the actuator arm.

6. An inkjet printhead as claimed in claim 3, in which each heater element is of copper while each actuator arm is of polytetrafluoroethylene.