Printhead integrated circuit comprising thermal bend actuator

• US 7,159,968 B2
• Filed: 06/24/2005
• Issued: 01/09/2007
• Est. Priority Date: 10/16/1998
• Status: Expired due to Fees

• Current Assignee: Zamtec Limited (Memjet Limited)
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Silverbrook, Kia
• Primary Examiner(s): JACKSON, JUANITA DIONNE
• Application Number:
  US11/165,302
• Publication Number:
  US 20050243134A1
• Time in Patent Office: 564 Days
• Field of Search: 347/20, 347/44, 347/47, 347/54, 347/56, 347/61, 347/63, 347/65, 347/62, 347/67
• US Class Current: 347/54
• CPC Class Codes: B05D 2201/00 Polymeric substrate or laminate
• CPC Class Codes: B05D 3/08 by flames
• CPC Class Codes: B41J 2/04528 aiming at warming up the head
• CPC Class Codes: B41J 2/04541 Specific driving circuit
• CPC Class Codes: B41J 2/04543 Block driving
• CPC Class Codes: B41J 2/04553 detecting ambient temperature
• CPC Class Codes: B41J 2/04563 detecting head temperature; Ink temperature
• CPC Class Codes: B41J 2/04571 detecting viscosity
• 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 2/04591 Width of the driving signal being adjusted
• CPC Class Codes: B41J 2/04596 Non-ejecting pulses
• CPC Class Codes: B41J 2/14 Structure thereof only for on-demand ink jet heads
• 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 2/1626 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 2/1639 : 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 2002/14419 : Manifold
• CPC Class Codes: B41J 2002/14491 : Electrical connection
• CPC Class Codes: Y10T 29/49345 : Catalytic device making

Abstract

A printhead integrated circuit comprising a drive circuitry and a plurality of nozzles is provided. Each nozzle comprises a chamber for holding ink to be ejected, the chamber having an opening defined in a roof structure; and a thermal bend actuator for ejecting droplets of ink from the chamber through the opening. The bend actuator is configured as a cantilever with one end of the cantilever anchored to a base and the opposite end supporting a paddle. The actuator has a deflector section constructed of a material having a high coefficient of thermal expansion and a barrier layer constructed of a dielectric material having low thermal conductivity. A supply of current from the drive circuitry to the deflector section causes differential thermal expansion between the deflector section and the barrier layer, such that the actuator bends and the paddle ejects a droplet of ink from the nozzle.

Claims

1. A printhead integrated circuit comprising a drive circuitry and a plurality of nozzles, each nozzle comprising:

a chamber for holding ink to be ejected, the chamber having an opening defined in a roof structure;

a thermal bend actuator for ejecting droplets of ink from the chamber through the opening, the bend actuator being configured as a cantilever with one end of the cantilever anchored to a base and the opposite end supporting a paddle, the actuator having a deflector section constructed of a material having a high coefficient of thermal expansion and a barrier layer constructed of a dielectric material having low thermal conductivity;

wherein supply of current from the drive circuitry to the deflector section causes differential thermal expansion between the deflector section and the barrier layer such that the actuator bends and the paddle ejects a droplet of ink from the nozzle.

2. The printhead integrated circuit of claim 1 wherein the deflector section is configured to provide a spatial thermal pattern along the cantilever such that the resultant temperature change is greater at the base end of the cantilever than the paddle end of the cantilever.

3. The printhead integrated circuit of claim 2 wherein the deflector section is a first deflector layer and the device further comprises a second deflector layer, wherein the barrier layer is bonded between the first deflector layer and the second deflector layer such that the spatial heating pattern causes a substantially greater temperature increase of the base end than the paddle end of the first deflector layer.

4. The printhead integrated circuit of claim 3 wherein the second deflector layer is constructed of the same material as the first deflector layer and the second deflector layer is substantially equal in thickness to the first deflector layer.

5. The printhead integrated circuit of claim 2 wherein the deflector section is a thin film resistor layer and the spatial thermal pattern results in part from spatially modifying the conductivity of the thin film resistor layer.

6. An inkjet printhead comprising a plurality of printhead integrated circuits according to claim 1.