Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1998-06-10
2001-06-12
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06244690
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for jetting ink of an ink-jet print head, and more particularly, to an apparatus for jetting ink by utilizing a magnetic force.
2. Description of the Prior Art
Apparatuses for jetting ink applied to conventional drop-on-demand (DOD) ink-jet print heads employ either a heating system which uses a surface heating element or a piezoelectric system which uses a piezoelectric element.
As shown in
FIG. 1
, an apparatus
10
for jetting ink of the heating system is formed such that a lower insulating layer
14
, a heating element
16
, electrodes
18
, an upper insulating layer
20
and a protecting layer
22
are sequentially stacked on a printed circuit board (hereinafter referred to as “PCB”)
12
. Passage walls
23
are installed between a nozzle plate
24
and the protecting layer
22
to form an ink chamber
26
. Then, the ink chamber
26
is connected to a reservoir (not shown), and both electrodes
18
are connected with a driving signal generator
28
.
When a driving signal is supplied to the electrodes
18
from the driving signal generator
28
, heating element
16
is heated, and ink
27
within the ink chamber
26
is boiled. At this time, bubbles
29
are produced within the ink chamber
26
, and the bubbles
29
push the ink
27
within the ink chamber
26
out of a nozzle
25
of the nozzle plate
24
, thereby ejecting an ink jet
30
. The ink jet
30
is ejected from the nozzle
25
in accordance with the driving signal, i.e., a print signal.
As shown in
FIG. 2
, an apparatus
40
for jetting ink of a piezoelectric system is provided with a PCB
42
, a diaphragm
44
, a piezoelectric element
46
, a spacer
48
and a nozzle plate
50
. An ink chamber
54
is formed by the diaphragm
44
, the piezoelectric element
46
and the nozzle plate
50
. The interior of the ink chamber
54
is filled with ink
53
.
If a driving signal is supplied to the piezoelectric element
46
from a driving signal generator
52
, the piezoelectric element
46
mechanically expands and contracts. An ink jet
55
is produced by ejecting the ink
53
within the ink chamber
54
out of the nozzle
51
by the expanding and contracting action of the piezoelectric element
46
.
However, the apparatus
10
for jetting ink using the heating system deleteriously requires so much time for generating the bubbles that the ejecting speed of the ink, i.e., the print speed, is slowed down, and the characteristics of the heat emitting body (heating element
16
) are liable to be changed in connection with the surrounding temperature. The apparatus
40
for jetting ink using the piezoelectric system has a drawback of incurring high cost due to the use of the high-priced piezoelectric element
46
.
Furthermore, both ink-jet apparatuses
10
and
40
, using the heating system and the piezoelectric system, respectively, involve a fastidious manufacturing process which thereby degrades the productivity of such apparatuses.
On the other hand, U.S. Pat. Nos. 4,057,807 and 4,210,920 disclose ink-jet apparatuses for ejecting ink by vibrating a magnetically active diaphragm plate by means of an electromagnet.
The ink-jet apparatuses described in the above U.S. Pat. Nos. 4,057,807 and 4,210,920 are equipped with a magnet driver attached to the outside of a nozzle of a head and the magnetically active diaphragm plate for sealing an ink chamber. The ink is ejected by a pressure which is exerted when the magnetically active diaphragm plate is deformed by a magnetic field generated by the magnet driver.
However, according to these conventional ink-jet apparatuses, when any one magnet driver coil is magnetized, a secondary current becomes induced to another driver coil nearby. Therefore, the magnetically active diaphragm plate of another magnet driver side is activated to eject the ink from another undesired nozzle.
Therefore, it is difficult to obtain a favorable printing quality. Further, the magnet driver is attached to the outside of the nozzle to make the ink-jet apparatus bulky in its construction.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an apparatus for jetting ink of an ink-jet printer which is simplified in structure, facilitated in manufacturing and stabilized in operation, and which is capable of controlling an ejecting pressure and speed of the ink to improve the printing quality and printing speed.
Additional objects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
To achieve the above and other objects of the present invention, there is provided an apparatus for jetting ink including a magnet, a vibrating plate placed at an upper portion of the magnet, and a plurality of coils installed on the vibrating plate for generating a magnetic field. Also included as parts are an ink chamber filled with the ink, and a nozzle for ejecting the ink from within the ink chamber by the deformation of the vibrating plate when an electric signal is applied to the coils.
Preferably, a gap control member is interposed between the vibrating plate and the magnet, which regulates a gap between the vibrating plate and the magnet.
More preferably, a nozzle plate is installed to an upper portion of the vibrating plate, which is provided with the nozzle. The nozzle plate defines the ink chamber in cooperation with the vibrating plate.
Here, an attraction or repulsion is exerted between the coils and the magnet when the electrical signal is applied to the coils. At this time, the ink chamber is pressed to externally eject the ink from within the ink chamber via the nozzle.
The apparatus for jetting the ink according to the present invention is effective in economizing the manufacturing cost by using the simplified structure and facilitated manufacturing. Also, the ejecting quantity and speed of the ink can be easily controlled to provide the advantageous of enabling high-speed printing having a high resolution.
REFERENCES:
patent: 4057807 (1977-11-01), Fischbeck et al.
patent: 4210920 (1980-07-01), Burnett et al.
patent: 4633267 (1986-12-01), Meinhof
patent: 4806955 (1989-02-01), Koto et al.
patent: 5854644 (1998-12-01), Eun
patent: 5986522 (1999-11-01), Asakawa et al.
patent: 3709455A1 (1988-10-01), None
patent: 0 888 888 A2 (1999-01-01), None
patent: 54-161337 (1979-12-01), None
patent: 4-368851 (1992-12-01), None
Patent Abstracts of Japan—JP 04 129745, Apr. 30, 1992—abstract.
Patent Abstracts of Japan—JP 04 327945, Nov. 17, 1992—abstract.
Patent Abstracts of Japan—JP 04 368851, Dec. 21, 1992—abstract.
Patent Abstracts of Japan—JP 06 238889, Aug. 30, 1994—abstract.
Kwon Oh-keun
Moon Chang-youl
Moon Jae-ho
Barlow John
Gordon Raquel Yvette
Samsung Electronics Co,. Ltd.
Staas & Halsey , LLP
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