Inkjet printhead with nozzle pokers

• US 6,488,362 B2
• Filed: 09/28/2001
• Issued: 12/03/2002
• 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:
  US09/966,290
• Publication Number:
  US 20020039125A1
• Time in Patent Office: 431 Days
• Field of Search: 347/54, 347/20, 347/320
• 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 each with an ink ejection nozzle aperture and a paddle moveable in each chamber by an actuator to deliver ink through the aperture. 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 having a plurality of nozzle devices each comprising:

an ink chamber having an ink ejection aperture,

a paddle situated within the chamber,

an actuator connected to the paddle so as to move the paddle toward the aperture,

a projection extending from the paddle and configured to extend through the aperture when the paddle is moved by the actuator toward the aperture to eject a drop of ink from the chamber through the aperture.

2. The printhead of claim 1 wherein the ink chamber of each nozzle device is supplied with ink via at least one conduit in an underlying substrate.

3. The printhead of claim 1 wherein the projection is an elongate poker member, a free end of which is positioned to protrude at least into the aperture when the paddle is moved by the actuator toward the aperture to eject a drop of ink from the chamber.

4. The printhead of claim 1 wherein the projection of each nozzle device is located concentrically with the aperture.

5. The inkjet printhead of claim 1 wherein the aperture is formed by MEMS process in which a series of layers are deposited and etched and the projection comprises a hollow cylindrical column.

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

7. The printhead of claim 1 wherein the actuator is a thermal bend actuator conductively heated so as to cause movement of said paddle.

8. The printhead of claim 1 wherein the projection is located substantially centrally on the paddle.

9. In an inkjet printhead having a plurality of nozzle devices, each including an ink chamber having an ink ejection aperture, a paddle situated within the chamber and an actuator connected to the paddle so as to move the paddle toward the aperture, a method of improving operational characteristics of the printhead comprising the step of:

locating a projection on the paddle configured to extend through the aperture when the paddle is moved by the actuator toward the aperture to eject a drop of ink from the chamber through the aperture.