Ink jet printing mechanism

• US 6,244,691 B1
• Filed: 07/10/1998
• Issued: 06/12/2001
• Est. Priority Date: 07/15/1997
• Status: Expired due to Fees

• Current Assignee: Zamtec Limited (Memjet Limited)
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Silverbrook, Kia
• Primary Examiner(s): Barlow, John
• Assistant Examiner(s): Do, An H.
• Application Number:
  US09/113,084
• Time in Patent Office: 1,068 Days
• Field of Search: 347/20, 347/44, 347/54, 347/55, 347/47
• US Class Current: 347/54
• CPC Class Codes: B41J 2/14 Structure thereof only for on-demand ink jet heads
• CPC Class Codes: B41J 2/14314 Structure of ink jet print heads with electrostatically actuated membrane
• CPC Class Codes: B41J 2/16 Production of nozzles
• CPC Class Codes: B41J 2/1623 bonding and adhesion
• 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 2/1639 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 2002/041 Electromagnetic transducer

Abstract

This patent describes an ink jet printer which ejects drops on demand by activating a permanent magnetic piston located above a nozzle chamber. An activation coil is located adjacent to the magnetic piston and applies a force to the piston sufficient to cause movement of the piston resulting in the ejection of ink. Torsional springs attached to the magnetic piston cause the piston to return to a quiescent condition upon deactivation of the activation coil.

Claims

1. An ink jet printing nozzle apparatus comprising:

a wafer substrate having a nozzle chamber defined therein to be in fluid communication with an ink chamber so that ink to be ejected by said nozzle apparatus can be stored in the nozzle chamber, said wafer substrate also defining an outlet port opening into the nozzle chamber for the ejection of ink from said nozzle chamber;

a magnet ic piston located over an ink inlet aperture in said nozzle chamber; and

an activation coil located adjacent to said magnetic piston, said coil and said magnetic piston being configured so that, upon activation by a current set up in the coil, an electromagnetic force is applied to said piston that is sufficient to cause movement of said piston from a first position to a second position, said movement causing ink within said nozzle chamber to be ejected from said nozzle chamber through said outlet port onto print media.

2. An ink jet printing nozzle apparatus as claimed in claim 1 further comprising at least one spring attached to said magnetic piston the, or each, spring being configured to return said magnetic piston to said first position upon deactivation of said activation coil.

3. An ink jet nozzle apparatus as claimed in claim 2 wherein the, or each, spring comprises a torsional spring.

4. An ink jet printing nozzle apparatus as claimed in claim 2 wherein the, or each, spring is constructed substantially of silicon nitride.

5. An ink jet printing nozzle apparatus as claimed in claim 1 wherein said wafer substrate defines a nozzle rim adapted to reduce hydrophilic surface spreading of said ink.

6. An ink jet printing nozzle apparatus as claimed in claim 1 wherein said activation coil is constructed substantially of copper.

7. An ink jet printing nozzle apparatus as claimed in claim 1 wherein said magnetic piston is constructed substantially of a rare earth magnetic material.