Printhead with drive transistors and corresponding ink ejection actuators

• US 7,210,764 B2
• Filed: 10/02/2006
• Issued: 05/01/2007
• 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): JACKSON, JUANITA DIONNE
• Application Number:
  US11/540,566
• Publication Number:
  US 20070030315A1
• Time in Patent Office: 211 Days
• Field of Search: 347/20, 347/40, 347/44, 347/47, 347/54, 347/56, 347 61- 65, 60527-529
• US Class Current: 347/54
• CPC Class Codes: B41J 2/04518 reducing costs
• CPC Class Codes: B41J 2/04541 Specific driving circuit
• CPC Class Codes: B41J 2/04543 Block driving
• 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 2/14427 Structure of ink jet print heads with thermal bend detached actuators
• CPC Class Codes: B41J 2/1623 bonding and adhesion
• CPC Class Codes: B41J 2/1628 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 2/1637 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

Abstract

A printhead for ejecting ink includes a substrate defining a plurality of ink supply channels. A plurality of nozzles is operatively mounted to the substrate. Each nozzle defines a respective ink chamber in fluid communication with a respective ink supply channel and an aperture through which ink can be ejected. A plurality of elongate actuators each have a thermally actuated arm with one end fixed to the substrate and a free end extending into a respective ink chamber. Each actuator configured to move on receipt of an electrical signal to eject ink from the ink chamber through its corresponding aperture. Each arm has a heater element. A drive circuitry layer is positioned on the substrate. The drive circuitry layer includes a plurality of drive transistors connected to the heater elements of corresponding respective actuators. The drive transistors are interposed between their associated actuators and the substrate.

Claims

1. A printhead for ejecting ink, the printhead comprising:

a substrate defining a plurality of ink supply channels;

a plurality of nozzles operatively mounted to the substrate and defining respective ink chambers in fluid communication with respective ink supply channels and apertures through which ink can be ejected;

a plurality of elongate actuators each comprising a thermally actuated arm with one end fixed to the substrate and a free end extending into a respective ink chamber and configured to move to eject ink from the corresponding aperture, each thermally actuated arm having a heater element; and

a drive circuitry layer positioned on the substrate, the drive circuitry layer including a plurality of drive transistors connected to the heater elements of corresponding respective actuators, the drive transistors being interposed between their associated actuators and the substrate.

2. A printhead as claimed in claim 1, wherein each arm terminates at its free end in an enlarged paddle.

3. A printhead as claimed in claim 1, wherein the nozzles are arranged to form a plurality of pairs of spaced apart rows and, for each pair, the arms extending into the nozzles of one row being alternately interposed with the arms extending into the nozzles of the other row.

4. A printhead as claimed in claim 3, further comprising a plurality of ink reservoirs which are arranged so that, for each pair, ink supplied to the nozzles of one row is of a different type to ink supplied to the nozzles of the other row.

5. A printhead as claimed in claim 3, wherein each row is staggered along its length.

6. A printhead as claimed in claim 1, in which each drive transistor includes a series of traces oriented perpendicularly to the associated actuator arm, each heater element defining a series of corrugations that correspond with the traces of the respective transistors.

7. A printhead as claimed in claim 1, in which each actuator arm is laminated, with a heater layer defining the heater element and a structural layer to which the heater layer is attached.