Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1998-04-21
2001-02-13
Le, N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S054000
Reexamination Certificate
active
06186617
ABSTRACT:
CLAIM OF PRIORITY
This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from an application for DEVICE FOR STORING AND SUPPLYING ACTIVE LIQUID IN INK JET PRINTHEAD earlier filed in the Korean Industrial Property Office on the Apr. 21, 1998 and there duly assigned Ser. No. 14828/1997.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a device for storing and supplying an active liquid in an ink jet printhead and, more particularly, to a device for storing and supplying an active liquid in an ink jet printhead wherein a heating chamber is heated to change the shape of the membrane that separates an ink chamber storing the active liquid from the heating chamber and thereby the ink disposed in an ink chamber is jetted onto a print media.
2. Discussion of Related Art
Generally, an ink jet printer has a control section which is receptive to print data generated from a system. The control section processes the print data, generating a control signal for driving an ink jet printhead to jet ink stored therein through a nozzle in order to produce an image onto the media in response to the print data.
An exemplary ink jet printhead stores and jets ink in drops in response to the control signal applied from the control section. The exemplary ink jet printhead is includes: an elastic body for storing ink; a housing having the ink-storing elastic body built therein, and forming an ink filter which filters the ink and is glued to the bottom surface of the ink-storing elastic body, an ink stand pipe which forms a feeding path of the ink filtered through the ink filter, and an ink via; an ink injector for injecting the ink supplied through the ink via of the housing in drops in response to an electrical signal applied to an electrical connection; and a housing cover for covering the housing tightly by heat or ultrasonic fusion after the ink-storing elastic body is mounted in the housing, and making an orifice to maintain the atmospheric pressure constant.
The ink enjector of the exemplary inkjet printhead includes: a substrate providing a support; a metal layer deposited on the substrate; a heater deposited on the metal layer in a specified pattern to convert electrical energy to heat; two electrodes deposited in contact with the heater in order to supply electrical energy to the heater; a heating chamber barrier deposited on the upper surface of the two electrodes so as to form a heating chamber; plural membranes glued to the upper surface of the heating chamber barrier and heated by the heater to be expanded and changed in shape; an ink chamber barrier glued to the upper surface of the plural membranes so as to form an ink chamber; and a nozzle plate glued to form an orifice in accord to the ink chamber.
The ink jet printhead of such a configuration maintains the pressure in the housing at the atmospheric pressure through the orifice disposed at a specified position in the housing cover. Jetting ink through the ink injector while maintaining the pressure in the housing at the atmospheric pressure causes a suction, that is, a buoyant pressure generated from the jetting force.
The buoyant pressure produced in the ink enjector of the ink jet printhead forces the ink in an open shell formed in the ink-storing elastic body to be filtered through the ink filter and supplied to the ink enjector via the ink stand pipe and ink via.
The ink supplied to the ink enjector forms droplets and is jetted according to the electrical signal applied to the electrical connection. That is, electrical energy is applied to the heater through the two electrodes, wherein the heater is deposited in a specified pattern on the metal layer overlying the substrate which is to support the ink enjector.
The electrical energy applied to the heater heats the active liquid filled in the heating chamber to create the vapor pressure, which causes a plurality of membranes to be expanded.
In addition to the expansion of the plural membranes, the vapor pressure expands the ink which is supplied to the ink chamber defined by the ink via and the ink chamber barrier. As the expansion of ink interrupts the electrical energy supply to the two electrodes, the expanded ink forms droplets due to the surface tension and is jetted onto the print media.
Once the ink droplets are jetted through the ink enjector, external air is introduced through the orifice disposed at a specified position in the housing cover such that the top portion of the ink-storing elastic body is filled with air in an amount as much as the jetted ink. Under pressure as much as the amount of air that fills the top portion of the ink-storing elastic body, the ink moves down to the bottom of the elastic body.
The ink enjector jets the ink onto the print media to produce a font or graphic image according to the electrical signal applied from the electrical connection.
It is, however, difficult to check the complete enjection of the active liquid into the respective heating chambers disposed in the ink enjector of the ink jet printhead utilizing membranes. Also, the enjector is inapplicable to long time use in that the active liquid within the ink injector is heated to vaporization or consumption, resulting in deterioration of the injection rate of the ink with a consequence of dot omission. Furthermore, as the ink chamber is formed with the active ink jetted thereinto, the formation of the ink chamber is difficult in the exemplary art.
U.S. Pat. No. 4,364,059 to Nagayama, entitled Ink Jet Printing Apparatus, discloses an ink jet printing apparatus whereby ink is recirculated from a reservoir through an ink ejection head and back to the reservoir while it has been heated prior to actual printing to purge air from the ink and prevent erroneous ejection. U.S. Pat. No. 4,580,148 to Domoto et al., entitled Thermal Ink Jet Printer With Droplet Ejection By Bubble Collapse, discloses a thermal ink jet printer with droplet ejection by bubble collapse, whereby a thermal ink jet printhead ejects ink droplets on demand by utilizing the conservation of momentum of collapsing bubbles in a layer of liquid ink having a predetermined thickness. It is disclosed that the printhead has an ink containing chamber with an array of individually addressable heating elements on one chamber interior surface which are aligned with an elongated opening in a parallel, confronting chamber wall. U.S. Pat. No. 4,788,556 to Hoisington et al., entitled Deaeration Of Ink In An Ink Jet System, discloses a deaeration of ink in an ink jet system, whereby an elongated ink path leading to an ink jet head is formed between two permeable membranes. The membranes are disclosed as being backed by air plenums which contain support members to hold the membranes in position. Reduced pressure is disclosed as being applied to the plenums to extract dissolved air from the ink in the ink path, and increased pressure can also be applied to the plenums to eject ink from the inkjet head for purging. It is disclosed that within the ink jet head ink is circulated convectively from the orifice to the deaerating path even when the jet is not jetting ink.
U.S. Pat. No. 5,084,713 to Wong, entitled Method And Apparatus For Cooling Thermal Ink Jet Print Heads discloses a method and apparatus for cooling thermal ink jet printheads. A thermal ink jet cartridge is disclosed which uses a resistor assembly to eject ink from the cartridge. To control heat generated by the resistors, a cooling system is disclosed as being provided that consists of an ink channel positioned adjacent the resistor substrate, with the channel being supplied with ink from a chamber within the cartridge. The ink flowing through the channel contacts the substrate, causing a cooling effect, the ink then being returned to the chamber in the cartridge. It is disclosed that the system may consist of a thin-film resistor positioned adjacent at least one of the openings provided between the channel and the chamber, and when the resistor is energized and heat
Bushnell , Esq. Robert E.
Le N.
Samsung Electronics Co,. Ltd.
Vo Anh T. N.
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