Inkjet printhead having thermal bend actuator with separate heater element

• US 6,443,558 B1
• Filed: 10/19/1999
• Issued: 09/03/2002
• Est. Priority Date: 10/16/1998
• Status: Expired due to Term

• Current Assignee: Memjet Technology Ltd. (Memjet Limited)
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Silverbrook, Kia
• Primary Examiner(s): Barlow, John
• Assistant Examiner(s): HSIEH, SHIH WEN
• Application Number:
  US09/425,193
• Time in Patent Office: 1,050 Days
• Field of Search: 347/54, 347/20, 347/44, 347/55, 347/62, 216/27, 438/21
• US Class Current: 347/54
• CPC Class Codes: B41J 2/04528 aiming at warming up the head
• CPC Class Codes: B41J 2/04553 detecting ambient temperature
• CPC Class Codes: B41J 2/04563 detecting head temperature; Ink temperature
• CPC Class Codes: B41J 2/0457 Power supply level being detected or varied
• CPC Class Codes: B41J 2/04585 controlling heads based on thermal bent actuators
• CPC Class Codes: B41J 2/04588 using a specific waveform
• CPC Class Codes: B41J 2/0459 Height of the driving signal being adjusted
• CPC Class Codes: B41J 2/04591 Width of the driving signal being adjusted
• CPC Class Codes: B41J 2/04596 Non-ejecting pulses
• CPC Class Codes: B41J 2/04598 Pre-pulse
• CPC Class Codes: B41J 2/14427 Structure of ink jet print heads with thermal bend detached actuators
• 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 2/1639 sacrificial molding
• CPC Class Codes: B41J 2/1642 thin film formation by CVD [chemical vapor deposition]
• 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 2002/14491 : Electrical connection

Abstract

An ink jet nozzle arrangement formed on a substrate comprising: a nozzle chamber having an ink ejection aperture in one wall thereof and an actuator interconnection aperture in a second wall thereof; an external thermal bend actuator interconnected at one end with an internal ink ejection paddle through the actuator interconnection aperture and, at a second end, affixed to the substrate; and a moveable internal ink ejection paddle, moveable under the control of the external thermal bend actuator for the ejection of ink out of the ink ejection aperture; wherein the external thermal actuator further can comprise a series of layers and preferably can include a planar conductive heating circuit layer which preferably can include a first portion adjacent the second end which forms a conductive circuit of heating the thermal bend actuator, and a second portion forming a portion of the ink ejection paddle, the second portion being electrically isolated from the first portion by means of a slot traversing the planar conductive heating circuit layer external to the nozzle chamber.

Claims

1. An inkjet printhead constructed by micro-elctromechanical (MEMS) processing techniques with a plurality of ink ejection nozzles, each nozzle comprising

a substrate;

a chamber-defining portion arranged on the substrate to define a nozzle chamber and a nozzle opening in communication with the nozzle chamber;

a pit located at least partially around a rim of said nozzle opening, said pit being adjacent said chamber-defining portion and extending from a level of said nozzle opening towards said substrate;

a thermal bend actuator arranged on the substrate externally of the nozzle chamber defining portion, the actuator having a proximal end anchored to the substrate and a distal end connected to an ink ejection paddle arranged within said chamber; and

the thermal bend actuator comprising a series of layers, one of said layers being a planar conductive heating circuit layer having a first portion extending from said proximal end towards said distal end and forming a planar conductive heating circuit for heating said thermal bend actuator, and a second portion extending from said ink ejection paddle towards said proximal end, said second portion being electrically isolated from said fist portion by means of a discontinuity in said planar conductive heating circuit layer, said discontiunity being located externally of said nozzle chamber.

2. An inkjet printhead as claimed in claim 1 wherein said discontinuity comprises a slot extending across said planar conductive heating circuit layer of the thermal bend actuator.

3. An inkjet printhead as claimed in claim 1 wherein said planar conductive heating circuit layer comprises substantially titanium nitride.

4. An inkjet printhead as claimed in claim 1 wherein said first potion of said planar conductive heating circuit layer includes a tapered slot portion widening towards said proximal end to increase resistive heating adjacent said proximal end.