Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
2001-10-16
2003-09-02
Vo, Anh T. N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
Reexamination Certificate
active
06612689
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink supply device that supplies ink into a sub ink tank of a recording head unit, an ink-jet recording device having the ink supply device, and a method of supplying ink.
2. Description of the Related Art
In the ink-jet recording device that ejects ink drops on a recording medium such as a paper from recording heads on the basis of image information and records the image, there is such a configuration that mounts the sub ink tanks corresponding to each of the recording heads on a carriage to make the recording heads scan, in which there are various types of proposals as to the supply of ink into the sub ink tanks.
For example, Japanese Published Unexamined Patent Application No. Hei 6-238911 discloses an ink-jet printer as shown in
FIG. 18
, in which an ink tank
314
is disposed on one end of the shifting range of a recording head
312
. The ink tank
314
has an ink supply outlet
318
formed at a position corresponding to an ink supply inlet
316
of the recording head
312
, and has a bellow portion
320
formed on the middle thereof. And, as the recording head
312
returns to the home position, the ink supply inlet
316
of the recording head
312
is connected with the ink supply outlet
318
of the ink tank
314
, and the recording head
312
is pressed to the ink tank
314
by a drive force of a drive motor not illustrated; thus, the bellow portion
320
of the ink tank
314
shrinks by this pressing force. Accordingly, the content volume of the ink tank
314
varies, and the ink inside the ink tank
314
flows into a common liquid chamber by way of the ink supply outlet
318
and the ink supply inlet
316
. The ink tank
314
that once shrank recovers the original volume by the recording head
312
shifting and releasing the pressure, and by a self-restoring force of the bellow portion
320
. AT this moment, a check valve
322
provided with the ink tank
314
opens, and the air equivalent to the volume of ink supplied into the recording head
312
flows into the ink tank
314
from an air intake
324
.
However, in the construction in which the supply of ink is carried out by such pressurization, the supply of ink can take a comparably long time in some cases, which sometime lowers the efficiency of the ink supply.
In contrast to this, as shown in FIG.
19
and
FIG. 20
, the Japanese Published Unexamined Patent Application No. Hei 11-240180 discloses an ink-jet recording device that includes a first tank
354
provided with a recording head
352
and a second tank
356
to supply ink into the first tank
354
. A switching hole
362
on a partition wall
360
that separates an ink chamber
358
of the first tank
354
from the recording head
352
can be opened and closed by a check valve
364
; and as a differential pressure is produced, the switching hole
362
is to open. Supply of ink into the ink chamber
358
needs to couple a suction hole
366
with a suction cap
368
, and thereafter drive a supply pump
370
, thus decompressing the first tank
354
. Next, a rubber seal
372
is made to advance by driving a reversible motor, and a needle
374
projected on the first tank
354
is inserted into the rubber seal
372
, whereby the first tank
354
is connected with the second tank
356
. Since the first tank
354
is in decompression, the ink is supplied from the second tank
356
into the first tank
354
by way of a tube
376
.
However, in this construction, since the first tank
354
is not made to communicate with the atmosphere, the check valve
364
is required in order to prevent an ink leakage or air suction through a nozzle
378
, due to a variation of the inner pressure, thereby making the structure complicated.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above circumstances, and provides an ink supply device that permits supply of ink securely with a simple construction into a sub ink tank having an air communication hole, a method of supplying ink, and an ink-jet recording device provided with the ink supply device.
According to one aspect of the invention, the ink supply device possesses an ink supply unit provided in correspondence with a recording head unit including a recording head that ejects ink drops onto a recording medium on the basis of image information, and a sub ink tank provided with an air communication hole, storing the ink supplied to the recording head, which implements ink supply by a pressure reduction part reducing a pressure inside the sub ink tank; and a sealing part that at least permits sealing of the air communication hole while the ink supply unit is reducing the pressure inside the sub ink tank.
According to this invention, the sub ink tank that the ink is supplied into is provided with the air communication hole. This air communication hole softens a surge pressure variation inside the sub ink tank, accompanied with ejection's of ink and/or environmental changes, and so forth, and prevents an unexpected ink leakage from the sub ink tank and a mixture of air (air suction from an ink discharging nozzle of the recording head, and creation of air bubbles inside the sub ink tank). Thus, the recording head maintains an optimum state for discharge of ink drops.
Also, since the ink supply device has the sealing part, at least the device is able to seal the air communication hole of the sub ink tank, while the ink supply unit is reducing the pressure inside the sub ink tank. In the sealing state, as the pressure reduction part reduces the pressure inside the sub ink tank, the air does not flow unexpectedly into the sub ink tank, and the ink flows securely into the sub ink tank, thus achieving a smooth ink supply.
In addition, the ink supply is carried out not by the pressurization but by the decompression inside the sub ink tank; and the ink supply can securely be carried out in a shorter time.
According to another aspect of the invention, the ink supply device further includes a displacement mechanism that displaces the ink supply unit in relation to the sub ink tank between a non-supply position where the ink is not supplied and a supply position where the ink is supplied, wherein the sealing part is provided with the ink supply unit, and it carries out sealing of the air communication hole, based on a displacement from the non-supply position to the supply position by the displacement mechanism.
That is, the ink supply unit is displaced by the displacement mechanism from the non-supply position to the supply position in relation to the sub ink tank. The ink supply unit is designed to supply ink into the sub ink tank at the supply position, where the ink is supplied into the sub ink tank.
As the ink supply unit displaces from the non-supply position to the supply position, by this displacement, the sealing part seals the air communication hole. In this manner, the utilization of the displacement of the ink supply unit simplifies the construction, and also secures the sealing of the air communication hole, interlocking with the ink supply operation into the sub ink tank.
Further, the sealing part is provided integrally with the ink supply unit.
Thereby, the ink supply device reduces the number of components, simplifies its construction to diminish the size, and reduces the manufacturing cost.
According to another aspect of the invention, the ink supply unit is provided with an air suction member and an ink supply member that are connected to the sub ink tank, and the sealing part is made to seal the air communication hole, after the air suction member and the ink supply member are connected to the sub ink tank.
Therefore, after the air suction member and the ink supply member are connected to the sub ink tank, the sealing part seals the air communication hole. In this state, as the air suction member sucks the air inside the sub ink tank, the ink flows into the sub ink tank from the ink supply member, resulting in supplying ink.
Now, in this series of operation, if the construction is such that the sea
Amarume Katsuhi
Ishize Tatsuhiro
Sekiyama Takaaki
Soga Mitsuhide
Suenaga Koji
Fuji 'Xerox Co., Ltd.
Vo Anh T. N.
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