Ink jet printhead with tapered magnetic actuators

• US 6,439,694 B1
• Filed: 05/14/2001
• Issued: 08/27/2002
• 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): Gordon, Raquel Yvette
• Assistant Examiner(s): Do, An H.
• Application Number:
  US09/854,815
• Publication Number:
  US 20020060719A1
• Time in Patent Office: 470 Days
• Field of Search: 347/20, 347/44, 347/47, 347/54, 347/48, 347/55
• 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 2/16585 for paper-width or non-reciprocating print heads
• CPC Class Codes: B41J 2/17596 Ink pumps, ink valves
• CPC Class Codes: B41J 2002/041 Electromagnetic transducer
• CPC Class Codes: H04N 1/2112 using still video cameras
• CPC Class Codes: H04N 1/2154 the still video camera incorporating a hardcopy reproducing device, e.g. a printer
• CPC Class Codes: H04N 2101/00 Still video cameras
• 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

A compact form of ink jet printer head is actuated upon interaction of an electromagnet with a magnetic plunger device. The magnetic plunger is located between a nozzle chamber and an ink supply reservoir and is surrounded by the electromagnetic device. Upon activation, the magnetic plunger is forced towards an ink ejection port resulting in ink ejection. The plunger is substantially circular and has a tapered rim adjacent portions of the electromagnetic device which is of a cylindrical shape with the plunger located in the center of the cylinder. The plunger is further connected to a spring device which causes the plunger to return to its original position upon deactivation of the electromagnetic device. The spring device is interconnected to a central portion of the plunger and radially spirals out to the side walls. It can be formed from the tensional release of a deposited material such as nitride.

Claims

1. An ink jet nozzle arrangement comprising:

a reservoir-defining means which defines an ink reservoir;

an ink ejection port in fluid communication with the ink reservoir; and

a magnetic ink ejection device interposed between the ink ejection port and the ink reservoir, the device being displaceably arranged relative to the port and having a region of varying reluctivity so that, upon the application of a magnetic field to said region, a force is imparted to the device to cause displacement of the device relative to the ink ejection port to cause ink ejection from the port.

2. The arrangement of claim 1 in which said region of varying reluctivity is a tapered portion of the device.

3. The arrangement of claim 2 which includes an actuator which acts on the device for effecting displacement of the device.

4. The arrangement of claim 3 in which the actuator is an electromagnetic unit which acts on at least the tapered portion of the magnetic device.

5. The arrangement of claim 2 in which the ink reservoir communicates with the ink ejection port by means of an ink supply channel, the magnetic device being arranged in said channel with its tapered portion facing toward the ink ejection port.

7. The arrangement of claim 1 which includes an urging means for urging the magnetic device to a rest position spaced from the ink ejection port.

6. The arrangement of clam 5 in which the magnetic device fits with clearance in said channel to define a gap through which ink can flow.