Printhead having multiple thermal actuators for ink ejection

• US 7,325,904 B2
• Filed: 05/30/2006
• Issued: 02/05/2008
• 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:
  US11/442,160
• Publication Number:
  US 20060227176A1
• Time in Patent Office: 616 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 2/1433 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 is provided including a substrate defining chambers for storing ink, with each chamber having an ink ejection port and actuators arranged to bend upon actuation to displace the port thereby ejecting ink therefrom. Each actuator incorporates a conductive resistive heating element encased within a material having a high coefficient of thermal expansion. Each heating element is configured to cause uneven expansion of the encasing material upon heating so that the actuator bends in a predetermined direction.

Claims

1. An inkjet printhead comprising a substrate defining a plurality of chambers for storing ink, each chamber having a wall with an ink ejection port and a plurality of actuators arranged in the wall on the same plane as the port so as to bend upon actuation to displace the port thereby ejecting ink therefrom, each actuator incorporating a conductive resistive heating element having a serpentine form and encased within a material having a high coefficient of thermal expansion, each heating element being configured to cause uneven expansion of the encasing material upon heating so that the associated actuator bends in a predetermined direction.

2. An inkjet printhead according to claim 1, wherein each heating element is configured to cause the associated actuator to bend inwards away from the centre of the chamber upon heating.

3. An inkjet printhead according to claim 1, wherein the actuators of each chamber are arranged radially around the associated port.

4. An inkjet printhead according to claim 1, wherein the actuators of each chamber form a membrane between the interior and exterior of the chamber.

5. An inkjet printhead according to claim 4, wherein the heating elements of each chamber are configured to cause the associated actuators to bend away from the exterior of the chamber to cause an increase in ink pressure within the chamber thereby initiating a consequential ejection of ink from the associated port.

6. An inkjet printhead according to claim 1, wherein each heating element is configured to cause the associated actuator to bend away from a central axis of the associated port.

7. An inkjet printhead according to claim 1, wherein the substrate further defines a plurality of ink supply channels, each channel being in fluid communication with a respective chamber.

8. An inkjet printhead according to claim 1, wherein each chambers has a series of struts which support the associated port in spaced relationship from the substrate.

9. An inkjet printhead according to claim 1, wherein the chambers are defined within the substrate in an array so as to form a pagewidth printhead.