Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
2000-09-15
2002-06-04
Nghiem, Michael P. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
Reexamination Certificate
active
06398353
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink tank used for a liquid discharge recording apparatus for obtaining recorded images by discharging ink to the recording surface of a recording medium. The invention also relates to a liquid discharge recording apparatus provided with such ink tank. More particularly, the invention relates to an ink tank for ink jet use in the ink jet recording field, and to a printing apparatus provided with such ink tank as well.
2. Related Background Art
Conventionally, in the field of an ink jet recording apparatus, there has been proposed for an ink discharge head an ink tank that exerts negative pressure therein. As one of the easiest methods for generating negative pressure, there is a method to utilize the capillary force of a porous member. The ink tank that uses a method of the kind comprises a porous member, such as sponge, preferably compressed to be housed entirely inside an ink tank for the purpose of retaining ink; and an atmospheric communication port capable of inducing the air into the ink containing portion in order to smooth the ink supply during printing operation.
Here, however, the lower efficiency of ink storage per unit volume may be encountered as a problem when the porous material is used as an ink retaining member.
As the structures of ink tank that may be able to solve a problem of the kind, those shown in FIG.
12
and
FIG. 13
are known.
FIG. 12
is a cross-sectional view which shows the structure of a first conventional example. As shown in
FIG. 12
, the first conventional example is divided into a first containing chamber
51
and a second containing chamber
50
. Between the first containing chamber
51
and the second containing chamber
50
, an opening portion
63
is arranged. With this opening portion
63
, the first containing chamber
51
and second containing chamber
50
are communicated.
For the first containing chamber
51
, a porous member formed by urethane sponge or the like is housed as the negative pressure generating member
56
. The negative generating member
56
is kept in a state where ink has been absorbed, and the ink-filling portion
58
on the lower part of the negative generating member
56
is filled in with ink. In the negative pressure generating member
56
, there is formed ink passage (hereinafter referred to as ink path) through which ink is supplied to the recording head
61
. Also, for the second containing chamber
50
, ink
53
is retained.
On the lower part of the negative generating member
56
, a compressed contact member
59
, which is formed by fibers solidified by heat or the like, is inserted, and the ink supply tube
62
through which ink is supplied to a recording head
61
is pressurized to be in contact with the compressed contact member
59
by way of a filer
60
.
On the upper part of the first containing chamber
51
, the atmospheric hole
55
is arranged through which the air outside
55
A flows into the second containing chamber
50
. Also, on the side wall that separates the first containing chamber
51
and second containing chamber
50
, an atmospheric induction groove
62
is arranged to enable the air outside
55
A entering from the atmospheric communication hole
55
to flow into the second containing chamber
50
as a bubble
54
.
Now, hereunder, with reference to
FIG. 12
, the operation of the conventional example will be described.
When a printing apparatus begins its printing operation, the ink which has been absorbed into the negative pressure generating member
56
is consumed at first. Thus, the ink boundary face
57
of the first containing chamber
51
is lowered. As ink consumption advances so that the height of the ink boundary face
57
of the first containing chamber
51
is made from a level at A to a level at B in
FIG. 12
to reach the upper edge of the atmospheric induction groove
62
, the air outside
55
A which has entered by way of the atmospheric communication hole
55
is induced into the second containing chamber
50
as a bubble
54
through the negative pressure generating member
56
and the atmospheric induction groove
62
. When a bubble
54
enter the second containing chamber
50
, the amount of air in the second containing chamber
50
becomes greater to press the ink boundary face
52
of the second containing chamber
50
downward.
Thus, the portion of ink which has been pressed downward is allowed to flow into the first containing chamber
51
through the opening portion
63
. The ink
53
that has flown into the first containing chamber
51
is once absorbed into the negative pressure generating member
56
. Then, through the ink path thereof (not shown) ink is supplied to the recording head
61
by way of the compressed contact member
59
, the filter
60
, and the ink supply tube
62
, hence ink
53
in the second containing chamber
50
being consumed. After that, ink
53
in the second containing chamber
2
is continuously consumed until ink
53
in the second containing chamber
50
is completely used. After ink
53
in the second containing chamber
50
is no longer available, ink remaining in the negative pressure generating member
56
is consumed. When this ink is completely used, the ink tank becomes empty.
Now,
FIG. 13
is a cross-sectional view which shows a second conventional example.
The structure of this conventional example is almost the same as that of the first conventional example shown in FIG.
12
. However, the connecting unit (a rubber plug
70
) of a recording head
73
is arranged on the lower part of the second containing chamber
50
which is not communicated with the air outside. This is difference between them. The recording head
73
and the second containing chamber
50
are coupled by the joint needle
71
of the recording head
73
which is pierced into the rubber plug
70
arranged on the bottom face of the second containing chamber
50
.
Hereunder, with the reference to
FIG. 13
, the operation of this conventional example will be described.
When a printing apparatus begins its printing operation, the ink which has been absorbed into the negative pressure generating member
56
is consumed at first as in the first conventional example, and the height of the ink boundary face of the first containing chamber
51
is lowered. As ink consumption advances so that the height of the ink boundary face
57
of the first containing chamber
51
is made from a level at A to a level at B in
FIG. 13
to reach the upper edge of the atmospheric induction groove
62
, the air outside
55
A is induced into the second containing chamber
50
as a bubble
54
through the atmospheric induction groove
62
. When a bubble
54
enter the second containing chamber
50
, the amount of air in the second containing chamber
50
becomes greater to press the ink boundary face
52
of the second containing chamber
50
downward.
Thus, the portion of ink
53
which has been pressed downward is allowed to flow directly into the recording head through the joint needle
71
. Ink
53
in the second containing chamber
50
begins to be consumed. After that, ink
53
in the second containing chamber
50
is continuously consumed until ink
53
in the second containing chamber
50
is completely used. Even after ink
53
is no longer available in the second containing chamber
50
, ink still remains in the negative pressure generating member
56
. Here, however, the ink tank is considered to have been completely used up irrespective of such ink remainders in the ink tank.
Both ink tanks shown in FIG.
12
and
FIG. 13
are excellent in the ink retaining efficiency.
Now, in accordance with the second conventional example shown in
FIG. 13
, the negative pressure in the second containing chamber
50
is lost and the pressure becomes positive after ink
53
in the second containing chamber
50
has been completely consumed. As a result, the remaining ink in the negative pressure generating member
56
is no longer used and remains as it is. Also, there is a problem that the ink
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Nghiem Michael P.
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