Information
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Patent Grant
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6585360
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Patent Number
6,585,360
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Date Filed
Tuesday, November 28, 200023 years ago
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Date Issued
Tuesday, July 1, 200321 years ago
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Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 347 85
- 347 86
- 347 87
- 347 92
- 222 187
- 239 43
- 239 44
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International Classifications
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Abstract
An ink tank, having an ink reservoir separated from an ink supply chamber which contains at least one foam element, is provided with one or more pipes in the partition which separates the ink reservoir from the ink supply chamber. The pipes transport ink from the ink reservoir to a portion of the ink supply chamber which does not contain the at least one foam element. This results in both minimizing leakage from the ink tank when the ink tank's protective seal is removed prior to inserting the ink tank into a print engine, and in more predictable ink supply pressure and accuracy from the ink tank to a print device.
Description
BACKGROUND OF THE INVENTION
1. Field of Invention
This invention is directed to construction of ink tanks used in print engines such as, for example, ink jet printers.
2. Description of Related Art
Conventional ink tank designs typically have seals which are removed when the ink tank is placed into a print engine. These ink tanks have been known to experience problems with leakage of ink when the seal, such as, for example, a foil seal, is removed prior to placing the ink tanks into the print engine. The leakage problem is often exacerbated when the ink tank seal is removed at the somewhat relatively lower atmospheric pressure which exists at high altitude locations. Some conventional tanks have a number of ink reservoir chambers. Any air trapped inside of these one or more ink reservoir chambers expands, when the seal is removed and the tank is directly exposed to relatively lower atmospheric pressure, to reach pressure equilibrium with respect to the relatively lower ambient atmospheric pressure. This expansion of air inside of the formerly sealed ink tank occurs rapidly and causes a rapid surge of ink from the one or more ink reservoir chambers where the air is located into the ink tank foam chamber, where an ink supply opening is located. This ink moves via a path or paths of least resistance, which often includes the ink tank supply opening, resulting in ink dripping out of this opening from the ink tank.
Moreover, some conventional ink tanks tend to have relatively poor ink supply consistency and accuracy. In a typical application, an optical sensing system is used to detect when the ink in the ink tank falls below a certain level. In such ink tanks, the amount of ink delivered between the ink reservoir chambers and the ink foam chamber, where an ink supply opening is located, is important in order to provide an accurate measure of how much usable ink remains in the ink tank. The amount of ink remaining in the ink tank when sensed low can be unpredictable due to the variable density and resistance to fluid and air flow that is inherent with foam. In addition, if the resistance of the foam to air flow to the rear chamber is extreme, the ink tank may “deprime” resulting in a severe defect on the customer's print.
SUMMARY OF THE INVENTION
This invention provides an ink tank construction which reduces the leakage of ink from an ink tank when the protective seal is removed.
This invention separately provides an ink tank construction that is able to reduce the leakage of ink from an ink tank when the protective seal is removed at relatively high altitudes.
This invention separately provides an ink tank construction which provides a low impedance path to conduct the ink from an ink reservoir portion of the ink tank into a safe area of the tank.
This invention separately provides an ink tank construction that uses a low impedance path to determine and regulate the ink supply pressure of an ink tank to
In various exemplary embodiments of the ink tank construction according to this invention, this low impedance path comprises one or more pipes extending between an ink reservoir chamber and an ink supply chamber. In other various exemplary embodiments of the ink tank construction according to this invention, this low impedance path decouples the ink supply of ink to the ink supply chamber from the ink supply of ink from the ink supply chamber. This renders the ink supply consistency and accuracy less dependent on the known variability in density and ink flow resistance of foam.
These and other features and advantages of this invention are described in, or are apparent from, the following detailed description of various exemplary embodiments of the systems and methods according to this invention.
BRIEF DESCRIPTION OF THE DRAWINGS
Various exemplary embodiments of this invention will be described in detail, with reference to the following figures, wherein:
FIG. 1
is a cross-sectional view of an ink tank with a removable seal covering the ink supply opening and vent tube;
FIG. 2
is a cross-sectional view of the ink tank with its seal removed and an ink manifold pipe inserted in the ink supply opening;
FIG. 3
is a cross-sectional view of one exemplary embodiment of an ink tank according to this invention having one or more pipes between an ink reservoir and a foam containing chamber and a removable seal covering the ink supply opening and vent tube;
FIG. 4
is a cross-sectional view of the ink tank of
FIG. 3
with the removable seal removed; and
FIG. 5
is a cross-sectional view of the ink tank of
FIG. 3
with an ink manifold pipe inserted in the ink supply opening.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1
is a cross-sectional view of a conventional ink tank
10
. The ink tank
10
has an ink supply chamber
110
and an ink reservoir chamber
130
. The ink reservoir chamber
130
is partially filled with ink
20
. The remaining space
30
above the ink
20
is filled with air. The ink supply chamber
110
has an ink supply opening
50
. A large portion of the ink supply chamber
110
is taken up by a foam element
120
, which forms a lower boundary between the ink supply chamber
110
and the ink reservoir
130
. The ink reservoir
130
is separated from the ink supply chamber
110
by a partition wall
75
, which does not completely separate the two chambers, but permits the ink
20
to flow between the ink supply chamber
110
and the ink reservoir chamber
130
, through an opening
121
formed between the partition wall
175
and the bottom of ink tank
10
. In one exemplary embodiment, the opening
121
was about 3mm high and about 9mm wide.
The ink tank
10
also has an ink tank vent
52
which opens into a bottom wall
15
of the ink tank
10
.
FIG. 1
shows a removable seal
56
, which may be made of any ink impermeable material, such as, for example, a metal foil. The removable seal
56
covers both the ink supply opening
50
and the ink tank vent,
52
.
FIG. 2
shows the ink tank
10
after the removable seal
56
has been removed and the ink tank
10
has been positioned on an ink supply pipe
40
. The ink supply pipe
40
has been inserted into the ink supply opening
50
and has displaced part of the foam
120
adjacent to the ink supply pipe
40
. The ink
20
in the ink reservoir chamber
130
is shown as having bubbles. In order for bubbles to form in the ink reservoir
130
, a portion
125
of the foam
120
has to become desaturated. Desaturating a portion
125
of the foam
120
in ink tank
10
, thus providing a free passage for the air bubbles to reach the ink reservoir chamber, has been unpredictable, prior to this invention, due to variations in the properties of the foam, some of which are due to the manufacture of the foam
120
. An arrow indicates the direction of flow of the ink
20
from ink reservoir
130
into the foam
120
across a foam boundary
121
.
FIG. 3
shows one exemplary embodiment of an ink tank
100
according to this invention, with its removable seal
56
intact, i.e., prior to removal of the seal
56
and installation of the ink tank
100
on the ink tank supply pipe
40
. The ink tank
100
contains one or more pipes
60
formed in the partition wall
175
which separates ink reservoir chamber
130
and the ink supply chamber
110
. The pipes
60
are molded into the partition wall
175
between the ink supply chamber
110
in which the foam element
120
is located and the ink reservoir chamber
130
. The top of each pipe
60
is located above the top of the foam
120
, which is generally kept below the spacer elements
17
in
FIG. 3
in the ink supply chamber
110
. This leaves an air space
31
into which the ink, which can be forced up the pipes
60
in response to a pressure difference between the ink reservoir and ink supply chambers, can enter. In various exemplary embodiments, the air space
31
and the long pipes
60
are formed during the molding process and the opening needed to form the pipes is sealed off with a seal
16
located on the top wall of the ink tank
100
. The pipes
60
can be sized as small as capillaries or larger, and can have capillary sized openings at the bottom of the one or more pipes but be larger in diameter or cross-section above the opening at the bottom end of the one or more pipes
60
. Spacer elements
17
keep the foam element
120
from filling the entire ink supply chamber
110
, and provide an air chambers
31
above the foam element
120
. The air chambers
31
are interconnected by openings
28
in spacer elements
17
so that all of the air above the foam element
120
is at the same pressure.
FIG. 4
shows the ink tank
100
after the removable seal
56
has been removed, and prior to insertion of the ink tank supply pipe
40
into the ink tank supply opening
50
. When the ink tank
100
is opened up by removing the removable seal
56
, the air in the top portion
30
of ink reservoir chamber
130
forces the ink
20
up into one or more of the pipes
60
. The ink
20
that is forced up into the pipes
60
overflows onto the top of foam element
120
, where this ink
20
can be absorbed.
FIG. 5
shows the ink tank
100
after the ink tank supply pipe
40
has been inserted into the ink tank
100
. During supply of the ink
20
from the ink supply chamber
110
via the ink supply pipe
40
, the air bubbles out of the bottom of pipes
60
into the ink reservoir chamber
130
. The pressure needed to pull the ink
20
through the pipes
60
and to generate an air bubble in the rear, reservoir, chamber, determines the operating or negative pressure of the ink tank
100
. The ink tank operating pressure can be adjusted or tuned by molding a fine hole at the bottom exit of the long pipe
60
. In various exemplary embodiments, the fine hole has a diameter of, for example, between 0.5 mm and 1 mm.
In some exemplary embodiments, the pipe
60
may be larger in diameter throughout most of its length than the opening
61
in the bottom of the pipe
60
. This tends to facilitate flow of air bubbles into the space
31
above the pipe
60
. The amount of the ink
20
drawn out of the ink tank
100
before the first bubble occurs between the foam
120
and ink reservoir chamber
130
is relatively more predictable in the ink tank
100
with one or more of the pipes
60
, because the impedance of the foam to air is not a significant factor.
This invention provides an ink tank that is configured to substantially reduce the possibility that ink will leak from the ink tank when the protective seal is removed prior to installing the ink tank and after the ink tank is installed on an ink tank supply pipe.
In various exemplary embodiments, the pipe is formed in or on the partition wall, where the partition wall defines at least a portion of the surface of the pipe. In other exemplary embodiments, a separate pipe can be placed in the ink tank to connect the ink tank reservoir and the ink tank supply chamber
110
. In this case, the pipe can be attached to the partition wall, but does not need to be so attached.
In various exemplary embodiments, as outlined above, the ink is delivered to the ink supply chamber
110
that does not contain the at least one foam element
120
, and thus does not contain the ink
20
. In various other exemplary embodiments, the ink is delivered to a portion of the at least one foam element
120
that, during normal operation, is not saturated with ink, i.e., a portion of the at least one foam element
120
that has subportions that do not contain the ink
20
. In this case, the air space
31
can be omitted, such that the at least one foam element
120
at least substantially fills the ink supply chamber
110
.
One other advantage of this invention is the reduction in deprime situations, i.e., situations in which air, instead of ink, is drawn through the foam element
120
to the ink supply orifice
50
. In a deprime situation, the ink supply tube
40
draws air along with, or instead of, the ink
20
into the ink supply tube
40
to the print head (not shown). This happens when air is drawn into the bottom of the foam element
120
and displaces the
20
ink in the bottom of the foam element
120
. In exemplary embodiments of this invention, however, air is displaced from the bottom of the foam element
120
into the ink reservoir chamber
130
and drawn up into the air space
31
on top of the foam element
120
by the one or more pipes
60
. In this manner, the ink is drawn from the ink reservoir
130
into the foam element
120
. As a result, deprime situations occur significantly less often.
While this invention has been described in conjunction with the exemplary embodiments outlined above, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the exemplary embodiments of the invention, as set forth above, are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention.
Claims
- 1. An ink tank, comprising:an ink tank reservoir; an ink supply chamber having an ink supply opening usable to discharge ink from the ink tank through the ink supply opening; at least one foam element located in a portion of the ink supply chamber; an air ventilation chamber located above the foam chamber in a portion of the ink supply chamber; a partition located between the ink tank reservoir and ink supply chamber such that the ink supply chamber is located in side-by-side relationship with the ink tank reservoir; and at least one pipe connecting the ink tank reservoir and the air ventilation chamber.
- 2. The ink tank of claim 1, wherein a portion of the at least one foam element is not saturated with ink.
- 3. The ink tank of claim 2, wherein the non-saturated portion of the at least one foam element is located in the upper portion of at least one of the at least one foam element when the ink tank is in an operating position.
- 4. The ink tank of claim 1, wherein each of the at least one pipe contains an exit opening at the bottom of the pipe when the ink tank is in an operating position.
- 5. The ink tank of claim 1, wherein the at least one pipe is attached to the partition.
- 6. The ink tank of claim 1, wherein the connecting pipe has a capillary sized opening.
- 7. The ink tank of claim 1, wherein the connecting pipe is a capillary tube.
- 8. An ink tank, comprising:an ink tank reservoir; an ink supply chamber integral with the ink tank reservoir; at least one foam element located in a portion of the ink supply chamber; an air ventilation chamber located above the foam element in a portion of the ink supply chamber in which at least one foam element is not located comprising the air ventilation chamber; a partition located between the ink tank reservoir and ink supply chamber; and at least one pipe connecting the ink tank reservoir and the air ventilation chamber; wherein the pipe is positioned to transport ink from the reservoir to a portion of the ink supply chamber in which at least one foam element is not located.
- 9. An ink tank, comprising:an ink tank reservoir; an ink supply chamber integral with the ink tank reservoir; at least one foam element located in a portion of the ink supply chamber; an air ventilation chamber located above the foam element in a portion of the ink supply chamber; a partition located between the ink tank reservoir and ink supply chamber; and at least one pipe connecting the ink tank reservoir and the air ventilation chamber wherein the at least one pipe is located in the partition.
- 10. The ink tank of claim 9, wherein the at least one pipe located in the partition is formed in the partition.
- 11. The ink tank of claim 9, wherein the at least one pipe located in the partition has at least one portion of a surface of the pipe defined by the partition.
- 12. A method of transferring ink within an ink tank that includes an ink reservoir and an ink supply chamber in side-by-side relationship, the ink supply chamber having an ink supply opening usable to discharge ink from the ink tank through the ink supply opening, with at least one foam element in a portion of the ink supply chamber and an airspace located above the at least one foam element in the ink supply chamber, the reservoir and supply chamber separated by a partition, wherein there is no partition between the foam element and the airspace, the method comprising:transferring ink from the ink reservoir to the ink supply chamber through at least one low-impedance path to the airspace.
- 13. The method of claim 12, wherein transferring the ink from the ink reservoir to the ink supply chamber through at least one low-impedance path comprises transferring the ink to the ink supply chamber through at least one pipe connecting the ink tank reservoir and the ink supply chamber.
- 14. A method of transferring ink within an ink tank that includes an ink reservoir integral with an ink supply chamber with at least one foam element in a portion of the ink supply chamber, the reservoir and supply chamber separated by a partition, the method comprising:transferring ink from the ink reservoir to the ink supply chamber through at least one low-impedance path to a portion of the ink supply chamber that does not contain ink; wherein a portion of the ink supply chamber does not contain the at least one foam element and comprises an air space above the foam element; and transferring the ink from the ink reservoir to the ink supply chamber through at least one low-impedance path to a portion of the ink supply chamber that does not contain ink comprises transferring the ink to the ink supply chamber to the portion of the ink tank that does not contain the at least one foam element.
- 15. A method of transferring ink within an ink tank that includes an ink reservoir and an ink supply chamber in side-by-side relationship, with at least one foam element in a portion of the ink supply chamber and an airspace located above the foam, the reservoir and supply chamber separated by a partition, the method comprising:transferring ink from the ink reservoir to the ink supply chamber through at least one low-impedance path to a portion of the ink supply chamber that does not contain ink and comprises the airspace; wherein: a portion of the at least one foam element is not saturated with ink; and transferring the ink from the ink reservoir to the ink supply chamber through at least one low-impedance path to a portion of the ink supply chamber that does not contain ink comprises transferring the ink to the ink supply chamber to a portion of the ink supply chamber containing the airspace and the portion of the at least one foam element that is not saturated with ink.
- 16. A method of transferring ink within an ink tank that includes an ink reservoir and an ink supply chamber having a foam element in side-by-side relationship, the ink supply chamber having an ink supply opening usable to discharge ink from the ink tank through the ink supply opening, the reservoir and supply chamber in side-by-side relationship and an airspace located in the supply chamber above the foam element, the reservoir and supply chamber separated by a partition, wherein there is no partition between the foam clement and the airspace, the method comprising:transferring ink from the ink reservoir to the airspace within the ink supply chamber through at least one pipe connecting the ink tank reservoir and the ink supply chamber.
- 17. A method of transferring ink within an ink tank that includes an ink reservoir and an ink supply chamber, the reservoir and supply chamber in side-by-side relationship and separated by a partition, the method comprising:transferring ink from the ink reservoir to the ink supply chamber through at least one pipe connecting the ink reservoir and the ink supply chamber, wherein: the ink supply chamber contains at least one foam element that occupies less than all of the ink supply chamber and an airspace located above the foam element; and transferring the ink from the ink reservoir to the ink supply chamber through at least one pipe connecting the ink reservoir and the ink supply chamber comprises transferring the ink to the airspace within the ink supply chamber.
- 18. A method of transferring ink within an ink tank that includes an ink reservoir and an ink supply chamber in side-by-side relationship, the ink supply chamber having an ink supply opening usable to discharge ink from the ink tank through the ink supply opening, with at least one foam element in a portion of the ink supply chamber and an airspace located in the ink supply chamber above the foam element, the reservoir and supply chamber separated by a partition having an opening, wherein there is no partition between the foam element and the airspace, the method comprising:transferring ink from the ink reservoir to the ink supply chamber through at least one pipe connecting the ink tank reservoir and the ink supply chamber, wherein: the ink supply chamber contains at least one foam element; and transferring the ink from the ink reservoir to the ink supply chamber through at least one pipe connecting the ink tank reservoir and the ink supply chamber comprises transferring the ink to the ink supply chamber to a portion of the ink supply chamber containing the airspace and a portion of the at least one foam element that is not saturated with ink.
- 19. An ink tank, comprising:an ink tank reservoir; an ink supply chamber integral with the ink tank reservoir; at least one foam element located in a portion of the ink supply chamber; an air ventilation chamber located above the roam element in a portion of the ink supply chamber; a partition located between the ink tank reservoir and ink supply chamber; and at least one pipe connecting the ink tank reservoir and the air ventilation chamber; wherein the air ventilation chamber is located entirely above the foam element in a portion of the ink supply chamber.
- 20. An ink tank, comprising:an ink tank reservoir; an ink supply chamber integral with the ink tank reservoir and having an ink supply opening usable to discharge ink from the ink tank through the ink supply opening; at least one foam element located in a portion of the ink supply chamber; an air ventilation chamber located above the foam element in a portion of the ink supply chamber; a partition located between the ink tank reservoir and ink supply chamber; and at least one pipe, connecting the ink tank reservoir and the air ventilation chamber.
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