Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
2002-04-30
2004-12-07
Nguyen, Lamson (Department: 2853)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
C347S084000, C347S085000
Reexamination Certificate
active
06827431
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink tank used for an ink jet recording apparatus.
2. Related Background Art
The ink jet recording apparatus is a recording apparatus of the so-called non-impact type, which is capable of recording on various recording mediums at high recording speed. Also, with the advantage, among some others, that almost no noise occurs at the time of recording, it is widely used. The ink jet recording apparatus of the kind performs recording on a recording medium by discharging fine ink droplets from minute nozzles, and it has, in general, an ink jet head provided with nozzles for discharging ink droplets and an ink tank that retains ink to be supplied to the ink jet head.
The conventional ink tank used for the ink jet recording apparatus is structured to adjust pressure exerted on ink in order to keep the ink supply from the ink tank to the ink jet head in good condition. For example, the structure is arranged to contain ink absorbent in the ink tank. When the ink tank having ink absorbent contained therein, it is arranged to keep ink in the ink jet head not to fall off from the ink discharge ports by holding the ink absorbent always in the negatively pressurized condition after taking into consideration the difference of water heads of the ink liquid surfaces in the ink discharge ports of the ink jet head and the ink tank. When the discharge energy is applied to ink, it is arranged to prevent ink from flowing out of the ink jet head excessively, and control to discharge only an appropriate amount of ink from the ink jet head. Also, after ink is discharged from the ink jet head, ink retained in the ink absorbent is carried to the ink jet head. However, in order not to allow ink to flow in continuously without any limit, ink is drawn to the ink absorbent appropriately by means of the negative pressure exerted in the ink absorbent. In this manner, pressure exerted on ink in the ink tank and ink jet head is adjusted by use of the ink absorbent.
FIG. 9
is a perspective view that shows the section of the conventional ink tank. As shown in
FIG. 9
, an ink absorbent
120
is contained in the containing portion of the ink tank
110
. A foaming element, such as urethane sponge, forms the ink absorbent
120
. Also, on the wall face of the containing portion of the ink tank
110
, plural ribs
101
are formed to extrude perpendicularly from the wall face. Each leading end of the plural ribs
101
is in contact with the ink absorbent
120
to secure the space that becomes each air passage
15
between the wall face having the ribs
101
formed thereon and the ink absorbent
120
. In this way, the air is evenly carried to the containing portion of the ink tank
110
through each of the air passages
15
thus secured to make it possible to use ink retained in the ink absorbent
120
efficiently. Also, the ribs
101
are in contact with the ink absorbent
120
to compress the ink absorbent
120
, thus presenting an appropriate negative condition.
As shown in
FIG. 9
, there often utilized a foaming element, such as urethane sponge, for the ink absorbent
120
contained in the conventional ink tank
110
. However, depending on the nature of ink to be used, the urethane sponge or some other foaming element chemically reacts upon ink when it is kept for a long time, and in some cases it is not necessarily suitable for use. In recent years, therefore, instead of the foaming element, such as urethane sponge, a laminated fibrous element, which is formed by material having preferably suitable ink preserving property, is sometimes used as the ink absorbent.
FIG. 10
is a perspective view that shows the ink tank
110
that contains the fibrous ink absorbent
121
(hereinafter abbreviated as an ink absorbent), which is formed by a lamination of plural sheet type fibrous element formed by thermally forming the laminated fibrous element, in place of the foaming element, such as urethane sponge.
On the wall face of the ink tank
110
shown in
FIG. 10
, the ribs
101
, which are similar to those shown in
FIG. 9
, are arranged. In other words, the ribs
101
that extend in the direction parallel to the laminated surface of the fibrous ink absorbent
121
. In this case, each of the ribs
101
tends to be buried as shown in
FIG. 10
as it enters the absorbent as if inserted into the gap of laminated fibrous material of the ink absorbent
121
, because the ribs
101
are in parallel to the laminated surface of the fibrous ink absorbent
121
. If the status becomes such as this, any sufficient air passage cannot be secured in the containing portion of the ink tank
110
. As a result, the air cannot be carried evenly into the containing portion of the ink tank
110
any more. Also, it becomes difficult for the ribs
101
to secure the condition of pressurized contact with the ink absorbent
121
, thus making it uneasy to generate designated negative pressure. Consequently, it often invites the condition that the ink use efficiency of the ink tank
110
is made lower.
On the other hand,
FIG. 11
is a perspective view that shows the ink tank
110
, which is in a state that as compared with the ink tank shown in
FIG. 10
, the direction of ribs
101
is rotated at 90 degrees or the direction of fibrous lamination arrangement is rotated at 90 degrees. In other words, on the wall face of the containing portion of the ink tank
110
shown in
FIG. 11
, the ribs
101
are formed in the direction intersecting with the fibrous lamination surface of the ink absorbent
121
.
With the structure thus arranged, such ribs
101
as shown in
FIG. 10
do not enter the fibrous lamination surface of the ink absorbent
121
as if inserted along it into the absorbent. Therefore, the air passages
150
can be secured. Nevertheless, there is a tendency that the ink absorbent
121
swells between ribs
101
and
101
, and such swelling portions of the ink absorbent
121
approach the wall face of the containing portion eventually. In this case, a part of the ink absorbent
121
is allowed to approach the inner opening of the atmosphere communication port
102
, which is communicated with the air passage
150
formed on the wall face to extruded, and which enables the interior of the ink tank to be communicated with the air outside. Then, there is a fear that ink leaks to the outside of the ink tank
110
from the atmosphere communication port
102
due to various causes, such as external vibration, environmental changes, or the like if ink retained in the ink absorbent
121
should exist too closely thereto.
Also, the air passage
150
functions as a buffer pace that temporarily holds ink leaking from the ink absorbent
121
when the ink tank
110
is affected by the environmental changes, such as temperature or pressure changes, and prevents it from leaking to the outside of the ink tank
110
immediately. However, if the ink absorbent
121
swells between ribs
101
and
101
to reduce the volume of the buffer space to make the function of the buffer space insufficient. Then, there is a possibility to allow ink leakage from the atmosphere communication port
102
easier.
In addition, the edge portion of the ink absorbent
121
(near the contact portion with the side face of the ink tank) is caused to swell greater than the other portions (in an image of springing up) depending on the positions of the ribs
101
thus arranged, and there is a possibility to invite such event as the edge portion is in contact with the upper face of the ink tank
110
. This may become a cause of ink leakage under such circumstance. Therefore, it is required more that ribs
101
should be arranged closer to the side face of the ink tank
110
.
As described above, if ribs
101
should be arranged so as to suppress the selling of the ink absorbent
121
in various locations, intervals between ribs
101
are made narrower eventually, and the resultant buffer spaces formed by the ribs
101
become smaller to make it impossible to demonstrate the buffer function sufficiently.
Hayashi Hiroki
Kitabatake Kenji
Kotaki Yasuo
Matsuo Keisuke
Takahashi Wataru
Canon Kabushiki Kaisha
Liang Leonard
Nguyen Lamson
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