Method and apparatus for redundant sealing of a printhead pressure regulator
First Claim
1. Apparatus for preventing ink from leaking from a print head of an ink-jet delivery system, said print head being adapted for ejecting droplets of ink selectively upon a proximate printing medium such that the droplets form graphics images and alphanumeric characters on the medium, wherein the print head is coupled to the apparatus such that the print head has an operating pressure of less than atmospheric pressure, and said system includes a source of ink having a supply pressure greater than the print head operating pressure, the apparatus comprising:
- a back pressure regulator fluidically coupling the source of ink and the print head such that the supply pressure is reduced to the operating pressure, said regulator includingfirst means for interrupting flow of ink from said source to said print head; and
second means for interrupting flow of ink from said source to said print head, said second means including a conduit means for connecting the source of ink with the back pressure regulator, the conduit means having a conduit and a conduit means open position and a conduit means shut position such that when the operating pressure approaches the atmospheric pressure, the conduit moves to the shut position, preventing ink from flowing into said regulator and leaking out of the regulator through the print head.
3 Assignments
0 Petitions
Accused Products
Abstract
A fail-safe, stop valve for an ink-jet print head in a pressurized ink delivery system. The stop valve is actuated by a back pressure regulator if the operating pressure of the print head approaches atmospheric pressure during operation.
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Citations
9 Claims
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1. Apparatus for preventing ink from leaking from a print head of an ink-jet delivery system, said print head being adapted for ejecting droplets of ink selectively upon a proximate printing medium such that the droplets form graphics images and alphanumeric characters on the medium, wherein the print head is coupled to the apparatus such that the print head has an operating pressure of less than atmospheric pressure, and said system includes a source of ink having a supply pressure greater than the print head operating pressure, the apparatus comprising:
a back pressure regulator fluidically coupling the source of ink and the print head such that the supply pressure is reduced to the operating pressure, said regulator including first means for interrupting flow of ink from said source to said print head; and second means for interrupting flow of ink from said source to said print head, said second means including a conduit means for connecting the source of ink with the back pressure regulator, the conduit means having a conduit and a conduit means open position and a conduit means shut position such that when the operating pressure approaches the atmospheric pressure, the conduit moves to the shut position, preventing ink from flowing into said regulator and leaking out of the regulator through the print head. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An ink delivery system for an ink-jet print head, comprising:
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an ink supply system having an ink reservoir and having means for delivering ink from the reservoir under a positive pressure; a back pressure regulator means for receiving ink from the reservoir and delivering ink to the print head a predetermined negative pressure with respect to ambient atmospheric pressure, the regulator means being fluidically coupled between the print head and the reservoir and the regulator means including an ink accumulation chamber and an intermediate ink chamber upstream of said ink accumulation chamber, the regulator means further including means for blocking delivery of ink from the intermediate ink chamber into the ink accumulation chamber when the accumulation chamber is full by balancing the ambient atmospheric pressure and the predetermined negative pressure; mounted within said regulator means, means for blocking delivery of ink from the reservoir into the intermediate ink chamber, including an ink conduit, a bi-stable biasing means for biasing the conduit into a first position in which the conduit is open, allowing free flow of ink from the reservoir into the intermediate ink chamber through the conduit into the ink accumulation chamber, and a second position in which the conduit is closed, blocking free flow of ink from the intermediate ink chamber into the ink accumulation chamber, the biasing means having a predetermined spring constant for maintaining the regulator means at said predetermined negative pressure during printing operation, and valving means for blocking flow of ink through said conduit independently of said biasing means.
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8. A method for preventing ink from drooling from a print head of a back pressure regulator ink-jet apparatus including a pressure regulator and adapted for use in a pressurized ink supply and delivery apparatus, said print head is mounted to said pressure regulator and is fluidically coupled to a source of ink there through by an ink conduit having an ink inlet orifice for receiving ink from the source and an ink outlet orifice for expelling ink into said regulator and is adapted for ejecting droplets of ink on to an adjacent printing medium, comprising the steps of:
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a) providing said pressure regulator between said source of ink and said print head for operating the print head at an operating pressure of less than atmospheric pressure; b) pressuring the source of ink to a source pressure greater than the print head operating pressure; c) delivering the ink through said ink conduit from the source to the print head, said ink conduit having a longitudinal axis, a first operating position in which the conduit is open to ink flow, and a second operating position in which the conduit is closed to ink flow; d) blocking delivery of ink to the print head if the operating pressure of the print head approaches atmospheric pressure during operation by either moving the conduit from the first position wherein the conduit permits ink flow there through to the second position wherein the conduit does not permit ink flow there through or by independently blocking at least one of said inlet orifice and said outlet orifice, thereby preventing pressure within said regulator from reaching atmospheric pressure and causing ink drooling from the print head. - View Dependent Claims (9)
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Specification