Inkjet printhead chip having drive circuitry for pre-heating ink

• US 6,799,835 B2
• Filed: 11/17/2003
• Issued: 10/05/2004
• 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): Gordon, Raquel Yvette
• Application Number:
  US10/713,063
• Publication Number:
  US 20040100529A1
• Time in Patent Office: 323 Days
• Field of Search: 347/54, 347/68, 347/69, 347/70, 347/71, 347/50, 347/40, 347/20, 347/44, 347/47, 347/27, 347/63, 399/261, 361/700, 310/328-330, 298/901
• 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

An inkjet printhead chip includes a substrate that incorporates drive circuitry. A plurality of nozzle arrangements is positioned on the substrate. Each nozzle arrangement includes a nozzle chamber wall and a roof wall positioned on the substrate to define a nozzle chamber, the roof wall defining an ink ejection port in fluid communication with the nozzle chamber. An ink ejection member is positioned in the nozzle chamber and is displaceable towards and away from the ink ejection port to eject ink from the ink ejection port. An elongate actuator is fast, at one end, to the substrate to receive an electrical signal from the drive circuitry and fast, at an opposite end, with the ink ejection member. The actuator incorporates a heating circuit that is connected to the drive circuitry layer. The heating circuit is positioned and configured so that, on receipt of, and termination of, a suitable electrical drive signal from the drive circuitry layer, the heating circuit serves to generate differential thermal expansion and contraction, respectively, such that the actuator is displaced to drive the ink ejection member towards and away from the ink ejection port. The drive circuitry is configured to generate a heating signal which is sufficient to heat the actuator, without generating movement, to an extent such that the ink is heated, prior to generating the drive signal.

Claims

1. An inkjet printhead chip that comprises

a substrate that incorporates drive circuitry;

a plurality of nozzle arrangements that are positioned on the substrate, each nozzle arrangement comprising;

a nozzle chamber wall and a roof wall positioned on the substrate to define a nozzle chamber, the roof wall defining an ink ejection port in fluid communication with the nozzle chamber;

an ink ejection member that is positioned in the nozzle chamber and is displaceable towards and away from the ink ejection port to eject ink from the ink ejection port; and

an elongate actuator that is fast, at one end, to the substrate to receive an electrical signal from the drive circuitry and fast, at an opposite end, with the ink ejection member, the actuator incorporating a heating circuit that is connected to the drive circuitry layer the heating circuit being positioned and configured so that, on receipt of, and termination of, a suitable electrical drive signal from the drive circuitry layer, the heating circuit serves to generate differential thermal expansion and contraction, respectively, such that the actuator is displaced to drive the ink ejection member towards and away from the ink ejection port, wherein

the drive circuitry is configured to generate a heating signal which is sufficient to heat the actuator, without generating movement, to an extent such that the ink is heated, prior to generating the drive signal.

2. A printhead chip as claimed in claim 1, in which the drive circuitry is configured to generate a series of pulses with pulses of a predetermined first duration defining heating signals and a series of pulses of a predetermined second duration defining drive signals.

3. A printhead chip as claimed in claim 1, which includes a number of temperature sensors that are connected to a temperature determination unit for detecting ink temperature and an ink ejection drive unit for determining whether or not preheating of the ink is required.

4. A printhead chip as claimed in claim 1, in which the drive circuitry is defined by CMOS circuitry positioned in the substrate, the CMOS circuitry incorporating control logic circuitry for each nozzle arrangement, which is connected to the heating circuit.

5. A printhead chip as claimed in claim 4, in which each control logic circuitry includes shift register circuitry for receiving a data input, transfer register circuitry that is connected to the shift register circuitry to generate a transfer enable signal and to latch the data input and to generate a firing phase control signal, and gate circuitry that is connected to the transfer register circuitry to be activated by the control signal to output a heating pulse which is received by the heating circuit.

6. A printhead chip as claimed in claim 1, in which each elongate actuator has a laminated structure of at least two layers, with one of the layers defining the heating circuit.

7. A printhead chip as claimed in claim 6, in which each elongate actuator has three layers in the form of a middle layer of a resiliently flexible, non-electrically conductive material, and a pair of opposite, substantially identical metal layers.