Inkjet printhead with nozzle pokers

• US 6,299,289 B1
• Filed: 10/19/1999
• Issued: 10/09/2001
• Est. Priority Date: 11/09/1998
• Status: Expired due to Fees

• Current Assignee: Zamtec Limited (Memjet Limited)
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Silverbrook, Kia
• Primary Examiner(s): NGUYEN, THINH H
• Application Number:
  US09/425,416
• Time in Patent Office: 721 Days
• Field of Search: 347/54, 347/20, 347/44, 347/75, 347/90
• US Class Current: 347/54
• CPC Class Codes: B41J 2/14427 Structure of ink jet print heads with thermal bend detached actuators
• CPC Class Codes: B41J 2/1626 etching
• CPC Class Codes: B41J 2/1629 wet etching
• CPC Class Codes: B41J 2/1639 sacrificial molding
• CPC Class Codes: B41J 2/1648 Production of print heads with thermal bend detached actuators

Abstract

An inkjet printhead, typically constructed by MEMS process, includes a large number of nozzle chambers with ink ejection nozzle apertures and a paddle moveable in each chamber by an actuator to deliver ink through the nozzle. Each paddle is provided with a projecting poker, concentrically protruding through the nozzle aperture when actuated to inhibit clogging of the nozzle.

Claims

1. An inkjet printhead comprising:

a plurality of nozzle chambers, each having a nozzle aperture defined in one wall thereof for the ejection of ink out of said aperture;

an ink supply channel interconnected with said nozzle chamber;

a paddle moveable within the nozzle chamber by an actuator and operable to eject ink from said nozzle chamber, said paddle having a projecting part which, upon operation of said actuator is caused to move towards said nozzle aperture.

2. An inkjet printhead as claimed in claim 1 wherein said projecting part, upon operation of said actuator, moves through the plane of said aperture.

3. An inkjet printhead as claimed in claim 1 wherein said projecting part is located concentrically with said nozzle aperture.

4. An inkjet printhead as claimed in claim 1 wherein said nozzle aperture is formed by MEMS process utilizing the deposition and etching of a series of layers and said projecting part comprises a hollow cylindrical column.

5. An inkjet printhead as claimed in claim 4 wherein said hollow cylindrical column includes a proximal end at the paddle and a distal end adjacent said aperture, said distal end being chemically mechanically planarized during the formation of said aperture.

6. An inkjet printhead as claimed in claim 1 wherein said actuator comprises a thermal bend actuator conductively heated so as to cause movement of said paddle.

7. An inkjet printhead as claimed in claim 1 wherein said projecting part is located substantially centrally on said paddle.

8. In an inkjet printhead having at least one chamber from which liquid is ejected from a nozzle aperture interconnected with said chamber by means of movement of a liquid ejection paddle, a method of improving the operational characteristics of said printhead comprising the steps of:

locating a projecting part on said moveable paddle, said projecting part undergoing movement towards said nozzle aperture upon activation of said liquid ejection paddle to eject liquid.

9. A method as claimed in claim 8 wherein said projecting part includes an end portion which moves through the plane of a rim of said aperture upon activation of said liquid ejection paddle.

10. A method as claimed in either claim 8 or claim 9 wherein said projecting part is arranged substantially concentrically with the nozzle aperture.