Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1997-07-24
2001-12-25
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06332668
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 APPARATUS FOR AND METHOD OF EJECTING INK OF AN INK-JET PRINTER earlier filed in the Korean Industrial Property Office on Jul. 24, 1996 and there duly assigned Serial No. 30047/1996.
FIELD OF THE INVENTION
The present invention relates to an apparatus for and method of ejecting ink of an ink-jet printer and, more particularly, to an apparatus for and method of ejecting ink of an ink-jet printer by applying low voltage across individual electrodes and the nozzle plate formed in different layers to produce an electrolysis of the conductive ink and generate gas, and ejecting the ink to openings using the vapor pressure of the gas to form characters.
DISCUSSION OF RELATED ART
The notion of vaporizing ink in a chamber as a way to expel ink from an orifice can be seen, for example, in U.S. Pat. No. 5,400,061 for an Ink-Jet Printer Head to Horio et al. Conductive ink is positioned between two electrodes and is heated until it vaporizes, forcing liquid ink to be expelled from an orifice. U.S. Pat. No. 5,648,805 for an Inkiet Printhead Architecture For High Speed and High Resolution Printing to Keefe et al discloses an inkjet printhead that can operate at a frequency of 12 kHz and with a resolution of 600 dots per inch. What is needed is an inkjet printhead that not only operates at higher frequencies, but can do so by applying a low voltage to the printhead.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to an apparatus for and method of ejecting in an ink-jet printer that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide an apparatus for and method of ejecting ink of an ink-jet printer, whereby the ink can be ejected out of the openings on the nozzle plate only by the vapor pressure of bubbles of gas generated in the electrolysis of the conductive ink by applying positive(+) voltage to individual electrodes wetted with the ink and negative(−) voltage to a common electrode, without using a heater for heating the ink and a plurality of protective layers to protect the internal electrodes.
Another object of the present invention is to provide an apparatus for and method of ejecting ink of an ink-jet printer, which is simple in construction and requires no heat-resistant ink or heating resistor layer.
A flirter another object of the present invention is to provide an apparatus for and method of ejecting ink of an ink-jet printer, which can be easily operated by low voltage and low current.
Yet a further object of the present invention is to provide an apparatus for and method of ejecting ink of an ink-jet printer, in which a designated portion of the openings of the nozzle plate is surrounded by a conductive layer to stabilize the electrolysis of the conductive ink according to the electric energy applied to the electrodes in a chamber, thereby enhancing the quality of characters printed.
Still another object of the present invention is to provide an apparatus for and method of ejecting ink of an ink-jet printer, which has the nozzle plate made up of a conductive layer consisting of nickel or platinum in the portion of the nozzle plates wetted with ink in the ink chambers, and an insulating layer in the portion corresponding to the media, to concentrate energy generated through the conductive ink and prevent the leakage of electric energy.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, an apparatus for ejecting ink of an ink-jet printer is made up of a plurality of individual electrodes located on a substrate whose surface is treated, with silicon dioxide, wetted with ink in a specified portion with the other portions being, insulated, and producing an electrolysis in the ink by first voltage applied to generate bubbles of gas on the surface thereof; nozzle plate used as a common electrode which correspond to the individual electrodes wetted with ink and are formed on different layers electrically isolated from one another, producing an electrolysis in the ink by electric power applied with the individual electrodes, and made up of conductive layers in the ink-wetted portion, insulating layers in a portion corresponding to media, and a plurality of openings for ejecting the ink onto the media there through; ink barriers for electrically isolating the ink-wetted portions on the surface of the individual electrodes from one another, increasing ejection force and linearity of vapor pressure to eject the ink to the openings by the bubbles, and providing walls for a fluid path to transfer the ink from an ink via through ink channels; ink chambers receiving the ink through the ink barriers and providing a space for generating bubbles by electric current density between the individual electrodes and nozzle plate; electrical connection means for supplying the first voltage to the individual electrodes and second voltage to the conductive layers of the nozzle plate to cause an electrolysis of the ink between the two electrodes; and switching devices for switching the electrical connection means by the signal of a CPU to control a printing operation. The first voltage is positive voltage and the second voltage is negative voltage and the ink is a conductive ink having a resistance in a predetermined range.
The present invention is applicable to a high speed printing operation for high frequency since a short impulse duration of low voltage is employed instead of a long impulse duration of high voltage to generates electric energy by joule heat. Since the bubbles are generated on the surface of the individual electrodes rather than at the edges of the electrodes, the corrosion can be reduced due to a uniform distribution of electric current.
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Barlow John
Brooke Michael
Bushnell , Esq. Robert E.
Samsung Electronics Co,. Ltd.
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