Thermal actuated ink jet printing mechanism

• US 6,302,528 B1
• Filed: 07/10/1998
• Issued: 10/16/2001
• 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:
  US09/112,808
• Time in Patent Office: 1,194 Days
• Field of Search: 347/44, 347/48, 347/54, 347/20, 347/47, 347/55
• 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 2/1628 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 2/1648 Production of print heads with thermal bend detached actuators
• 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: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: G06K 1/121 by printing code marks applying code marks to labels B65C9/46; marking or coding completed packages B65B61/26
• CPC Class Codes: G06K 19/06037 multi-dimensional coding
• CPC Class Codes: G06K 7/14 using light without selection of wavelength, e.g. sensing reflected white light G06K7/10831 - G06K7/1097 take precedence
• CPC Class Codes: G06K 7/1417 2D bar codes
• CPC Class Codes: G11C 11/56 using storage elements with more than two stable states represented by steps, e.g. of voltage, current, phase, frequency
• 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

An ink jet printing mechanism includes an ink reservoir in which ink can be contained and can be subject to periodic pressure variation. A moveable shutter is provided which is displaceable between a closed position covering the nozzle chamber and an open position allowing the nozzle chamber to be in fluid communication with the ink reservoir, the shutter being activated by an actuator. The actuator comprises a coiled thermal actuator. The thermal actuation is via one of differing resistivities, differing cross-sectional areas, differing thermal expansion, and differing thermal conductivities of the actuator.

Claims

1. An ink jet printing mechanism comprising:

(a) an ink reservoir in which ink can be contained and can be subject to a periodic pressure variation; and

(b) at least one ink jet nozzle arrangement, the, or each ink jet nozzle arrangement comprising;

(i) a nozzle chamber having an ink ejection port for the ejection of ink;

(ii) a moveable shutter that is displaceable between a closed position in which the shutter closes said nozzle chamber and an open position in which said nozzle chamber is in fluid communication with said ink reservoir; and

(iii) a coiled thermal actuator, connected to the moveable shutter, that is responsive to a control signal and that is configured so that a coil radius changes in response to the control signal, thereby displacing said moveable shutter between the closed and open positions upon activation of said control signal.

2. An ink jet printing mechanism as claimed in claim 1 wherein said coiled thermal actuator is configured so that, upon activation of said control signal, said coil radius increases to displace the moveable shutter.

3. An ink jet printing mechanism as claimed in claim 2 wherein the actuator is configured so that actuation of the actuator occurs as a result of one of differing resistivities of the actuator, differing cross-sectional areas of the actuator, differing coefficients of thermal expansion of a material of the actuator, and differing thermal conductivities of the material of the thermal actuator.

4. An ink jet printing mechanism as claimed in claim 1 wherein the mechanism includes an ultrasonic transducer to apply said periodic pressure variation, the transducer being in fluid communication with the ink in said ink chamber.

5. A method of printing by ejecting ink from a nozzle arrangement, the nozzle arrangement including a nozzle chamber in fluid communication with an ink reservoir, the nozzle arrangement comprising a nozzle chamber having an ink ejection port for the ejection of ink, a moveable shutter that is displaceable between a closed position in which the shutter closes said nozzle chamber and an open position in which said nozzle chamber is in fluid communication with said ink reservoir and a coiled thermal actuator, connected to the moveable shutter, that is responsive to a control signal and that is configured so that a coil radius changes in response to the control signal, thereby displacing said moveable shutter between the closed and open positions upon activation of said control signal, said method comprising the steps of:

(a) applying a periodic pressure wave to ink within said ink reservoir and opening said shutter at a first predetermined time, via the actuator, to allow the ejection of ink from said ink ejection port;

(b) maintaining said shutter in an open position to allow said nozzle chamber to be refilled from the ink reservoir; and

closing said shutter upon refilling of said nozzle chamber.

6. A method as claimed in claim 5 wherein said periodic pressure wave is generated to include periods of negative pressure within said ink reservoir and wherein said shutter remains open during periods of said negative pressure so as to cause separation of ejected ink from said nozzle chamber.

7. A method of ejecting ink as claimed in claim 6 wherein said periodic pressure wave is generated so that a period of negative pressure is followed by a period of positive pressure in which said nozzle chamber is refilled with ink.