Thermal bend actuated inkjet with pre-heat mode

• US 6,916,087 B2
• Filed: 05/10/2004
• Issued: 07/12/2005
• Est. Priority Date: 10/16/1998
• Status: Expired due to Fees

• Current Assignee: Memjet Technology Ltd. (Memjet Limited)
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Silverbrook, Kia
• Primary Examiner(s): TRAN, HUAN HUU
• Application Number:
  US10/841,536
• Publication Number:
  US 20040218016A1
• Time in Patent Office: 428 Days
• Field of Search: 347/185, 347/186, 347/54, 347/56, 347/57, 347/60, 347/5, 347 9- 14
• US Class Current: 347/60
• CPC Class Codes: B41J 15/044 Cassettes or cartridges containing continuous copy material, tape, for setting into printing devices
• CPC Class Codes: B41J 2/04506 aiming at correcting manufacturing tolerances
• 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 2/04565 detecting heater resistance
• CPC Class Codes: B41J 2/0457 Power supply level being detected or varied
• CPC Class Codes: B41J 2/04571 detecting viscosity
• CPC Class Codes: B41J 2/04573 Timing; Delays
• 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 2/155 for line printing
• 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 2/1631 : photolithography
• CPC Class Codes: B41J 2/1632 : machining
• CPC Class Codes: B41J 2/1634 : laser 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 2/1646 : thin film formation by sputtering
• CPC Class Codes: B41J 2/1648 : Production of print heads with thermal bend detached actuators
• CPC Class Codes: B41J 2/175 : Ink supply systems ; Circuit parts therefor
• CPC Class Codes: B41J 2/17563 : Ink filters
• CPC Class Codes: B41J 2002/14362 : Assembling elements of heads
• CPC Class Codes: B41J 2002/14419 : Manifold
• CPC Class Codes: B41J 2002/14491 : Electrical connection
• CPC Class Codes: B41J 2202/19 : Assembling head units
• CPC Class Codes: B41J 3/445 : Printers integrated in other types of apparatus, e.g. printers integrated in cameras
• CPC Class Codes: Y10T 29/49401 : Fluid pattern dispersing device making, e.g., ink jet

Abstract

An inkjet printhead with thermal bend actuators for ejecting ink from the nozzle apertures and drive circuitry for operating each thermal bend actuator in a normal mode wherein drive signals to the actuator ejects ink from the chamber, or a pre-heat mode wherein drive signals to the actuator heats ink in the chamber but does not eject ink from the chamber. The invention uses the drive signal to the bend actuator to generate heat to raise the temperature of the ink in the chamber, but controls the signal so that the actuator will not respond in a manner that will eject ink. After a brief pre-heat cycle, the drive circuitry can switch to normal operating mode and the bend actuators will eject ink for printing. With the ink temperature and viscosity within normal operating range, the print quality is not compromised.

Claims

1. An inkjet printhead comprising:

an array of nozzles, each having a chamber for storing ink to be ejected, a nozzle aperture in one side of the chamber, a thermal bend actuator for ejecting ink from the chamber through the nozzle aperture, a MEMS temperature sensor and drive circuitry for operating the thermal bend actuator in;

a normal mode wherein drive signals to the actuator ejects ink from the chamber; and

when the MEMS temperature sensor senses that the ink temperature is below a predetermined threshold, a pre-heat mode wherein drive signals to the actuator heats ink in the chamber but does not eject ink from the chamber.

2. An inkjet printhead according to claim 1 wherein the drive signals to the thermal actuator during pre-heat mode are a series of pulses, each with a duration that is insufficient for the thermal bend actuator to eject ink from the chamber.

3. An inkjet printhead according to claim 1 wherein the drive circuitry operates in pre-heat mode after periods of printer inactivity.

4. An inkjet printhead according to claim 1 wherein the array of nozzles is pagewidth and self cooling such that heat generatod by the thermal bend actuator during normal operating mode is removed by the ejected ink drops.