Micro-electromechanical liquid ejection device

• US 7,419,250 B2
• Filed: 06/23/2005
• Issued: 09/02/2008
• Est. Priority Date: 10/15/1999
• Status: Expired due to Fees

• Current Assignee: Memjet Technology Ltd. (Memjet Limited)
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Silverbrook, Kia
• Primary Examiner(s): Luu; Matthew
• Assistant Examiner(s): LEGESSE, HENOK D
• Application Number:
  US11/159,197
• Publication Number:
  US 20050231560A1
• Time in Patent Office: 1,167 Days
• Field of Search: 347/56, 347/60, 347/9, 347/17, 347/40, 347/47, 347/54, 347/61, 347/63, 347/70
• US Class Current: 347/63
• 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 2/0457 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 2/04591 Width of the driving signal being adjusted
• CPC Class Codes: B41J 2/04596 Non-ejecting pulses
• CPC Class Codes: B41J 2/14427 Structure of ink jet print heads with thermal bend detached actuators
• CPC Class Codes: B41J 2/1628 dry 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 2002/14362 Assembling elements of heads
• CPC Class Codes: B41J 2002/14491 : Electrical connection

Abstract

A micro-electromechanical device for ejecting liquid, such as ink, having a plurality of nozzle arrangements, each nozzle arrangement having a nozzle chamber, an actuator for ejecting the liquid from the nozzle chamber, and a heater to raise the temperature of the liquid to a predetermined temperature prior to ejection.

Claims

1. A micro-electromechanical device for ejecting liquid, the device comprising:

a plurality of nozzle arrangements, each nozzle arrangement having a nozzle chamber, an actuator for ejecting the liquid from the nozzle chamber, and a heater to raise the temperature of the liquid to a predetermined temperature prior to ejection, wherein the actuator is in the form of a thermal bend actuator of the type which deflects through the application of an electrical current that resistively heats the actuator, resulting in differential expansion of the actuator and subsequent deflection of the actuator, and the heater is a resistive heater on the actuator, that is heated with an electrical current selected so as to heat the actuator without deflection that causes ejection.

2. A micro-electromechanical device according to claim 1 further comprising a sensor for sensing the temperature of the liquid to determine the extent of heating needed to raise the temperature of the liquid to the predetermined temperature.

3. A micro-electromechanical device according to claim 1 wherein the electrical current selected so as to heat the actuator without deflection that causes ejection, comprises a series of pulses that are smaller than an ejection pulse applied to the actuator to cause deflection of the actuator.

4. A micro-electromechanical device according to claim 2 wherein the sensor monitors the temperature of the liquid during a printing operation such that the heater only heats the liquid when it is less than the predetermined temperature.

5. A micro-electromechanical device according to claim 1 fabricated on a wafer substrate for use as a printhead integrated circuit (IC) that further comprises drive circuitry positioned on the substrate and ink supply ducting to the nozzle chambers such that the liquid ejected from the nozzle chambers is ink.