Inkjet nozzle with CMOS compatible actuator voltage

• US 7,234,795 B2
• Filed: 08/23/2004
• Issued: 06/26/2007
• Est. Priority Date: 07/15/1997
• Status: Expired due to Fees

• Current Assignee: Memjet Technology Ltd. (Memjet Limited)
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Silverbrook, Kia
• Primary Examiner(s): STEPHENS, JUANITA DIONNE
• Application Number:
  US10/922,873
• Publication Number:
  US 20050024434A1
• Time in Patent Office: 1,037 Days
• Field of Search: 347/20, 347/54, 347 56- 59, 347 61- 63, 347/65, 347/67, 60527-529
• US Class Current: 347/54
• CPC Class Codes: B41J 2/14314 Structure of ink jet print heads with electrostatically actuated membrane
• 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 2/1637 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 2/1643 thin film formation by plating
• CPC Class Codes: B41J 2/1645 thin film formation by spincoating
• 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 2/16585 for paper-width or non-reciprocating print heads
• CPC Class Codes: B41J 2/17513 Inner structure
• CPC Class Codes: B41J 2/17596 Ink pumps, ink valves
• CPC Class Codes: B41J 2002/041 Electromagnetic transducer
• CPC Class Codes: B41J 2002/14346 : Ejection by pressure produced by thermal deformation of ink chamber, e.g. buckling
• CPC Class Codes: B41J 2002/14435 : Moving nozzle made of thermal bend detached actuator
• CPC Class Codes: B41J 2202/21 : Line printing
• CPC Class Codes: G06F 21/79 : in semiconductor storage media, e.g. directly-addressable memories
• CPC Class Codes: G06F 21/86 : Secure or tamper-resistant housings
• CPC Class Codes: G06F 2221/2129 : Authenticate client device independently of the user
• CPC Class Codes: G06K 1/121 : by printing code marks applying code marks to labels B65C9/46; marking or coding completed packages B65B61/26
• CPC Class Codes: G06K 19/06037 : multi-dimensional coding
• CPC Class Codes: G06K 7/14 : using light without selection of wavelength, e.g. sensing reflected white light G06K7/10831 - G06K7/1097 take precedence
• CPC Class Codes: G06K 7/1417 : 2D bar codes
• CPC Class Codes: H04N 23/00 : Cameras or camera modules comprising electronic image sensors; Control thereof
• CPC Class Codes: H04N 5/2628 : Alteration of picture size, shape, position or orientation, e.g. zooming, rotation, rolling, perspective, translation

Abstract

An inkjet drop ejection apparatus comprising:

• • a chamber with a nozzle and an ink inlet for fluid communication with an ink supply; and,
  • an actuator with associated drive circuitry for ejecting drops of ink through the nozzle; such that,
  • the drive circuitry transmits a drive signal to the actuator wherein the drive signal has a voltage less than 10 volts.

Limiting the actuator voltage to 10V allows the drive circuitry to be CMOS circuitry rather than bi-polar. These voltages are compatible with CMOS and therefore the drive circuitry can be ‘on chip’ rather than ‘off chip’ with a large number of external connectors. Hence, all fabrication uses CMOS VLSI and MEMS processes and materials. By avoiding the need for many external connectors, the nozzle design is compact and the VLSI fabrication techniques are relatively low cost with high yield.

Claims

1. An inkjet drop ejection apparatus comprising:

a chamber with a nozzle and an ink inlet for fluid communication with an ink supply; and

,

an actuator with associated drive circuitry configured for differential thermal expansion to eject drops of ink through the nozzle;

such that,

the drive circuitry generates a drive signal with a CMOS compatible voltage to cause the differential thermal expansion by Joule heating wherein after the differential thermal expansion, the actuator returns to a quiescent state in a manner that assists the ejected drop to separate from the ink in the nozzle.

2. An inkjet drop ejection apparatus as claimed in claim 1 wherein the apparatus one of an array of drop ejection apparatuses fabricated on a substrate using lithographic etching and deposition techniques.

3. An inkjet drop ejection apparatus as claimed in claim 2 wherein the substrate is an elongate silicon wafer chip with an array of more than 25000 of the ejection apparatusses.

4. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator comprises a material with a very high coefficient of thermal expansion, such that thermal expansion of the actuator causes ejection of, or assists the ejection of, ink from said nozzle.

5. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator comprises a polymer with a high coefficient of thermal expansion which is doped with conducting substances to increase its conductivity such that resistively heating the actuator results in mechanical motion which ejects or assists in ejecting ink from said nozzle.

6. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator moves to directly effect ejection of the ink drops without any mechanical amplification of the actuator motion.

7. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator is a differential expansion bend actuator capable of converting a high force, low travel mechanism to high travel, lower force mechanism.

8. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator is a trilayer bend actuator where the two outside layers are substantially identical.

9. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator comprises a stacked series of thin thermal bend actuators.

10. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator is a bend actuator cantilevered into the chamber from a fixed end, wherein the actuator has a region near the fixed end that flexes more readily than the remainder of said actuator.

11. An inkjet printhead comprising a substrate surface and an array of inkjet drop ejection apparatuses as claimed in claim 1, wherein the nozzles of the array are formed in the surface and the actuators move in a direction normal to the surface.

12. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator bends when energized.

13. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator is normally bent, and straightens when energized.

14. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator is coiled, and either coils further, or uncoils when energized.

15. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator has a middle region that bows or buckles when the actuator is energized.

16. An inkjet drop ejection apparatus as claimed in claim 1 wherein the nozzle is formed in a plate that is microfabricated from silicon.

17. An inkjet drop ejection apparatus as claimed in claim 1 wherein the nozzle is formed in a surface deposited as a layer using VLSI deposition techniques, wherein the nozzle is etched in said surface.

18. An inkjet drop ejection apparatus as claimed in claim 1 wherein the apparatus is formed on and through a substrate, and the nozzle is formed in a surface of the substrate such that the drops of ink are ejected normal to the surface.

19. An inkjet drop ejection apparatus as claimed in claim 1 wherein the apparatus is formed on and through a substrate, the nozzle is formed on a front surface of the substrate such that ink flows through the substrate, and ink drops are ejected from the front surface.

20. An inkjet drop ejection apparatus as claimed in claim 1 wherein the apparatus is formed on and through a substrate, the nozzle is formed on a rear surface of the substrate such that ink flows through the substrate, and ink drops are ejected from the rear surface.