Two plate reverse firing electromagnetic ink jet printing mechanism

• US 6,257,705 B1
• Filed: 07/10/1998
• Issued: 07/10/2001
• 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:
  US09/113,077
• Time in Patent Office: 1,096 Days
• Field of Search: 347/20, 347/44, 347/54.56, 347/84.85, 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 2/1626 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 2/1639 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

An ink jet print head uses a static plate and a movable plate to eject ink. A fixed electric copper coil is located within a nozzle chamber. The movable plate has an embedded electric coil located close to a fixed electric coil such that when a current passing through the coils is altered, the movable plate moves towards or away from the fixed plate. This movement causes ejection of ink from the nozzle chamber via an ink ejection port. A torsional spring is connected to the movable plate and the movable plate goes from a quiescent position to a spring loaded position upon activation of the coils. Upon deactivation of the coils the spring causes the movable coil to return to its quiescent position and to eject ink. The coils can have a stacked multi-level spiral of conductive material interconnected at a central axial point of the spiral.

Claims

1. An ink jet print head comprising:

(a) a nozzle chamber having walls and an ink ejection port at one of said walls;

(b) a fixed electric coil located within the chamber or within one of said walls of said chamber; and

(c) a movable plate, in which there is embedded another electric coil, located close to said fixed electric coil such that when a current passing through said coils is altered, the movable plate moves towards or away from said fixed electric coil and wherein said movement is utilized to eject ink from said nozzle chamber via said ink ejection port.

2. An ink jet print head as claimed in claim 1 further comprising:

a sprint connected to said movable plate wherein said movable plate goes from a quiescent position to a spring loaded position upon activation of said coils and upon deactivation of said coils said spring causes said movable coil to return to its quiescent position and to thereby eject ink from said ink ejection port.

3. An ink jet print head as claimed in claim 2 wherein said spring comprises a torsional spring attached to said movable coil.

4. An ink jet print head as claimed in claim 3 wherein a conductive strip is connected to said coils and is located within said torsional spring.

5. An ink jet print head as claimed in claim 1 wherein said electric coil of said movable plate comprises a stacked multi level spiral of conductive material.

6. An ink jet print head as claimed in claim 5 wherein said stacked conductive material is interconnected at a central axial point of said spiral.

7. An ink jet print head as claimed in claim 1 wherein said coils are electrically connected together to form a combined circuit.

8. An ink jet print head as claimed in any previous claim wherein said coils comprise substantially copper.

9. An ink jet print head as claimed in claim 1 wherein said coils are formed by a damascene construction process.

10. An ink jet print head as claimed in claim 1 wherein said nozzle is constructed utilizing a sacrificial etch to release a structure of said movable coil.

11. An ink jet print head as claimed in claim 10 wherein an outer surface of said nozzle chamber includes a series of small etched holes for etching of any sacrificial layer utilized in the construction of said ink jet print head.

12. An ink jet print head as claimed in claim 1 wherein said nozzle chamber includes a series of slots within the walls of said nozzle chamber so as to allow a supply of ink to said nozzle chamber.

13. A method of ejecting ink from a nozzle chamber utilizing electro-magnetic forces between two coils embedded into plates to cause movement of at least one of said plates, the movement further causing consequential ejection of ink from said nozzle chamber.

14. A method of ejecting ink as claimed in claim 13 wherein said plates comprise a movable plate and a fixed plate, said movable plate further being connected to a spring which upon said movement of said movable plate, stores energy such that upon deactivation of a current through said coils, said spring releases its stored energy to thereby cause movement of said movable plate so as to cause ejection of ink from said nozzle.