Inkjet printer comprising MEMS temperature sensors

• US 6,994,426 B2
• Filed: 04/11/2005
• Issued: 02/07/2006
• 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:
  US11/102,857
• Publication Number:
  US 20050174375A1
• Time in Patent Office: 302 Days
• Field of Search: 347/54, 347 56- 60, 347/185, 347/186, 400/120.08
• 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

A printer comprising an inkjet printhead having an array of nozzles is provided. Each nozzle comprises a chamber for storing ink to be ejected, an aperture defined in a wall of the chamber, a thermal bend actuator for ejecting ink from the chamber through the aperture, a MEMS temperature sensor and drive circuitry for operating the thermal bend actuator. The drive circuitry is operable in two modes: a normal mode wherein drive signals to each actuator ejects ink from the corresponding chamber, and a preheat mode wherein drive signals to each actuator heats ink in the corresponding chamber but does not eject ink from the chamber. The preheat mode is selected by the printer if the MEMS temperature sensors sense that the ink is below a predetermined temperature threshold.

Claims

1. A printer comprising an inkjet printhead, said printhead comprising:

an array of nozzles, each nozzle comprising 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 aperture, a temperature sensor and drive circuitry for operating the thermal bend actuator, wherein the drive circuitiy is operable in;

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

a preheat mode wherein drive signals to each actuator heats ink in the corresponding chamber but does not eject ink from the chamber, the preheat mode being selected by the printer if the temperature sensors sense that the ink is below a predetermined temperature threshold.

2. The printer according to claim 1, wherein the drive signals to the thermal actuators during preheat mode comprise a series of pulses, each pulse having a duration that is insufficient for the thermal bend actuator to eject ink from the chamber.

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

4. The printer of claim 1, wherein the printhead is a pagewidth printhead.

5. The printer of claim 4, wherein the printhead is self-cooling, such that heat generated by the thermal bend actuator during the normal operating mode is removed by the ejected ink drops.