Note: Descriptions are shown in the official language in which they were submitted.
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17044-01 1
LIQ~[JID CONTAINMENT AND DISPENSING DEVICE
CROSS REFERENCE TO RELATED APPL)(CATION
This application is 3 continuation-in-part of my co-pending application Serial
No. 09/103,803.
BACKGROUND OF THE INVENTION
1. FIELD OF ')('~ INVENTION
This invention relates to a liquid containment and dispensing device. More
particularly. this invention uelates to a liquid containment and dispensing
device with a self-
contained pump. The device of this invention is useful for containing and
dispensing printing
ink in an ink jet printer.
2. DESCRIPT1UN OF THE PRIOR ART
U.S. Patent 5,784,087 ('UVallace et al,), the disclosure of which is
incorporated
herein by reference, describes a liquid containment and dispensing device with
a self-
contained pump that was developed for use in containing dnd dispensing
painting ink in an
in lC jet p><xnter. The putxtp ox the aforesaid device includes a linearly
acting pumping member
that reciprocates within a pumping chamber, which is defined by a perimetrical
wall, and the
pumping chamber is covered by a thin, flexible diaphragm, which is fabricated
from a
laminate of thin Films. The diaphragm is then heat-staked to a free edge of
the perimetzical
wall that surrounds the pumping chamber.
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The use of a flexible diaphragm fabricated from a laminate of films require
great cart in its heat staking to the perirraetrieal wall of a. pumping
chamber, however, due to
the tendency of such a diaphragm to fotnt wrinkles around its outside as
sufficient material is
left in the central portion of the diaphragm to permit it to flex sufficiently
to accomrcaodate
the pumping motion of the pumping member. Further, the use of heat-staking to
secure the
diaphragm to the perimetrical wall also requires great care in the control of
the temperatures
used in the heat-staking operation, as excessively high temperatures can
degrade the thin
films used in the diaphragm, while excessively low temperatures can result in
a poor quality
seal between the diaphragm and the perimetfical wall.
, The device of the afcoresaid'087 patent uses a flexible pouch that is
fabricated
from a single sheet for containing ink, the single fJcxiblc sheet being formed
from a laminate
of thin films. The pouch of such reference is supported only at its open end,
and is
unsupported on its sides and closed end. However, ds is taught in U.S. Patent
Application
Serial No. 08/892,131 (Kamp), which is assigned to the assignee of this
application, and in its
published European counterpart, EP 0 89I 867 A2, it is desirable to totally
enclose the ink
pouch of such a device by a fraxxt.e that depends from zhe chassis of the
device. to which the
open end of the pouch is in fluid communication. Such a construction increases
the
resistance of the device to shock loads. In such a construction, a pouch
formed from a single
flexible sheet wss also used, the edges of the folds of the folded sheet in
such a device being
heat staked to the sides of the frame Gather than to one another. Tn such an
arrangennent,
however, there is also a tendency to form wrinkles around the extexi.or of the
pouch-fot'ming
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17044-01 3
sheet, at the location of its heat staking tv the frame. in order to leave
sufficient material in
the central portion of the sheet to define a cavity for holding ink.
SILTyINL4itY OF TI-IE INVEN'd'10N
According to the present invention, there is provided a liquid containment and
dispensing device. especially a liquid containment and dispensing device that
is useful in
containing and dispensing printing ink in an ink jet printer, with a pumping
chamber cover
chat does not tend to wrinkle around its outside, where it is joined to a free
edge of a
perimetrical wall of the pumping chamber. hurthcr, the invention as described
above
incorporates a crymped metallic ring to help secure the pumping chamber cover
to the free
edge of the perimetrical wall of the pumping chamber to augment the seal that
is formed
therebetween by heat-staking.
The elimination of wrinkles in the pumping chamber cover according to the
present invention is obtained by pre-shaping a sheetlike cover material by a
thermoforzxune
operation, to thereby provide a domed configuration to a central portion of
the cover that
1~ results in sufficient flexibility to accommodate the reciprocation of a
pumping clement
without requiring excessive material in the surrounding portion of the cover.
In the preferred
embodiment of the present invention, the cover is formed from a sheetlike
material that is a
thin laminate of two or more polymeric films, with a suitable adhesive between
adjacent
layers of such laminate to prevent delamination of the layers thereof. At
least one of the
films is a material with good resistance to oxygen and moisture vapor
transmission, such as
ethylene vinyl alcohol copolymer (>'VOFi), which is preferably used in the
interior of the
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laminate, with an inncrcnvst Iaycr of a low density polyethylene (LDPE), which
has good
flexibility and bonds well to the perimetrical wall of the pumping chamber
whey the wall and
the liquid containment and dispensing device chassis of which it is s part is
formed from
polyethylene by injection molding. The outermost layer of the pumping chamber
cover is
then formed from a high heat resistant polymer such as nylon (a polyamide
material) for good
resistance to abrasion and to prevent the film structure from sticking to the
heat staking die.
The elimination of wrinkles in the ink pouch of a device with a pouch
supporting frame according to the teachings of the aforesaid Serial No.
081892,131 is
obtained by constructing the pouch from an opposed pair of laminated sheets,
each of which
is pre-shaped into a domed configuration, for example, by thermoforming. The
edges of such
pre-shaped sheets are then heat staked to adjacent portions of the surrounding
frame, rather
than to one another, to define a pouch chat is closed on its sides and one
end, to thereby be
capable of retaining ink or other liquid in a suitable manner.
Accordingly, it is an object of the present invention to provide an improved
liquid cvntainmcrit and dispensing device of a type chat has a self-contained
pump. More
particularly, it is an object of the presctit inYCntion to provide a liquid
containment and
dispensing device as described above that has utility in containing and
dispensing printing ink
in an ink jet printer.
It is also an object of the present invention to provide an improved joint
between a pumping chamber cover amd az~ annular wall of a pumping chamber of a
liquid
containment and dispensing device of the type desczibed above.
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It is also an object of the present invention to provide a dcvicE of the
Foregoing
character with a.n improved liquid containing pouch.
It is also an object of the present invention to provide a device of the
foregoing
character in which improved shock resistance is imparted to the pouch by
surrounding its
sides and closed end by a frame to which the sides and closed end of the pouch
arc scalingly
joined and to do so without the Formation of wrinkles in the material of the
pouch in the
region of its juncture with the surrounding frame.
For a further understanding of the present invention and the objects thereof.
attention is directed to the drawing a.nd the following brief description
thereof. to the detailed
1D description,cf the preferred embodiment of the invention and to the
appended claims.
SRIJE;F DESCRIPT)(ON OF T)EdE DRAWING
Fig. 1 is an exploded, perspective view of a liquid containment and dispensing
device according to the preferred embodiment of the present invention;
Fig. 2 is sectional view, at an enlarged scale, taken on line 2-2 of Fig. 1;
I S Fig. 3 is a fragmentary view, at a further enlarged scale, of the element
illustrated in Fig. 2:
Fig. 4 is a front elevational view of a subassembly of the device that is
illustrated in Fig. 1;
Fig. 5 is an end clcvational view of the subassembly of Fig: ~4; and
20 Fig. 6 is an exploded, perspective view of the subassembly of Figs. 4 and
5.
DETAILED DESCRIY><ION OF THIE IPR.EFER)<tED Elv»ODIMENT
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17044-O1
A liquid conta.inmcnt and dispensing device according to the prefcrrcd
embodiment of the prcstnt invention is indicated generally by reference
numeral 10 in Fig. 1.
The liquid containment and dispensing device 10 is made up of a hard
protective shell 12 that
is closed at an end 12a, which will be the upper end when the device 10 is
installed, for
j example, in an ink jet printer. A molded plastic chassis 14 is installed in
an opposed, open
end i?b of the shell 12, and the chassis 14 has a pumping chamber 16 defined
and
suzzounded by a perimetrical wall 18. which is formed integrally with the
cha~si~ 14.
A pumping element 20, shown fragmentarily, is positioned within the
pumping chamber 16 and is reciprocable therein, a coil spring 22 being
provided to bias the
pumping element 20 away from the closed end 12a of the shell 12. The pumping
chamber 16
is closed by a cover or diaphragm 2d, whose outer portion is heat-staked to a
free edge of the
perimetrical wall 18 that surrounds the pumping chazxtber 16. The diaphragm 24
is then
further secured to the perimetrical wall 18 by an aluminum crimp ring 26 to
further cn~ure
that the seal between the diaphragm 24 and the perimetrical wall 18 remains
secure
1 S throughout the life of the, ink containment and dispensing device I0.
Ink or other liquid is dispensed from the liquid containment and dispensing
device IO by deflecting the central part of the diaphragm 24 to deflect the
pumping element
within the pumping chamber 16, against the force of the coil spring 20, to
thereby pump
the liquid from a flexible pouch (not shown in Fig. 1), which is secured to
the underside (in
20 the illustrated arrangement) of the ehassls 14 through a fluid outlet
portion 28 of the chassis
14, As thus far described, the liquid containment and dispensing device 10
functions in the
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17044-01
manner described in the aforesaid U.S. Patent 5,784,087, except that the
device of such
reference does not disclose the use of a crimp ring corresponding to the
cziznp ring 26 of the
device 10 of Fig. 1.
The device 10 of Fig. 2 differs further from the device of the aforesaid
refcrcncc in that the diaphragm 24 is preshaped, for example, by a
thermoforming operation,
to provide it with a domed central portion 24a and a planar surrounding edge
portion Zab,
which is the portion that is heat-staked to the perimetrical wall 18 on the
chassis 14. The
diaphragm ~4, thus, has sufficient excess nnaterial in its central portion 24a
without requiring
excess material in its surrounding edge portion 24b to be able to flex as
required during Lhc
lU pumping of ink or other li.c[uid xrom the device 10, as described above.
Such excess material
can lead to wrinkling in an otherwise planar diaphragm, which can cvmplieate
the problem in
propErly heat-staking a diaphragm to the free edge of a perimetric;~l wall of
a liquid
containment and dispensing device of the type described. Such wrinkling can
also cause
premature failure of the diaphragm material as a result of the lloxing cycle.
1 ~ As is shown in Fig. 2 and even more clearly in Fig. 3, the diaphragm 24 is
formed from a lamination of layers of polyrraeric materials of various
compositions. The
layers include an innermost layer 24c of any member of the polyethylene
material such as
LDPE, LLDPE, HDPE, metallocene PE, ethylene vinyl acetate and ethylene ethyl
acrylate or
blends thereof, preferably with a density in the range of 0.880gJec.-
0.964g./cc. Any such -
20 material has good strength and flexibility and heat-stakes well to the
perimetrical wall oP the
chassis 14 when the chassis 14 is formed of polyethylene. The diaphragm 24
also includes an
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intermediate layer 24d of a material with good resistance to gas and moisture
vapor
transmission, such as nylon and nylon co-polymers, PVDC and EVOH, which is the
preferred
material. The diaphragm 24 also includes an outermost layer tae of a polymer
selected for
high melt temperature, abrasion resistance and flex life, such as nylon and
nylon co-polymers
and polypropylene. Since the material of the layezs 24c. 24d, 24e, as
described, do not bond
well to one another. preferably layers 24f, 24g of an adhesive are provided
between adjacent
layers of the diaphragm 24 to prevent the layers 24c, 24d, 24e From
delaminating in service,
The diaphragm 24, as described, is preferably produced by co-extrusion
because adhesives used in co-extrusion arc usually higher in molecular weight
than those
used in laminated composites, such higher molecular weight adhesives being
less susceptible
to being dissolved by aggressive printing inks.
While Figs. 2 and 3 txtay create the impression that the diaphragm 24 has
substantial thickness, in practice, for a diaphragm 24 for a device 10 that is
designed t~
contain up to approximately 100 ml. of printing ink, a standard size, the
diaphragm 10 will
have a total thickness of the order of S mils (0.005 in.).
The molded plastic chassis 14 has a perimetrical frame 17 that depends
therefrom and is integral therewith, the frame 17 having a spaced apart
opposed pair of side
members 17a, 17b and a transversely extending bottom member 17c that extends
between the
side members 17a; 17b. An open-ended pouch indicated generally by reference
numeral 19 is
formed by seallngly joining the free, planar edges of an opposed pair of
generally cup-shaped
members 21. 23 to the side rracmbers 17a, 17b and the bottom member 17c, for
example, by
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17044-01
heat staking. In that regard, each cup-shaped member 21, 23 is forrncd from a
laminated
sheet into the illustrated cup-shaped. configuration. for example. by
thermoforming, and the
laminated sheet from which each cup-shaped member 2l, 23 is formed may
correspond, for
example, to the laminate used in the manufacture of the diaphragm 23 by co-
extrusion.
Because the interior of each of the cup-shaped members 21, 23 is pre-shaped,
as described..
its planar free edges 21a, 23 a, respectively, need not undergo any wrinkling
to nraatch up
precisely with the adjacent portions of the frame 17 in order to define a
pouch 19 with
sufficient internal volume to hold the required amount of ink or other liquid,
such as up to
100 ml. of such liquid. Thus, the heat staking of the members 21, 23 to the
frame 17 does not
IO involve quality assurance risks of the type involved in heat staking flat
sheets with sufficient
internal volume to the frame 17.
Although the best mode contemplated by the inventor for tarrying out the
present invention as of the filing date hereof has been shown and described
herein, it will be
apparent to those skilled in the art that suitable modifications, variations
and equivalents may
IS be made without departing from the scope of the invention, such scope beinb
limited solely
by the terms of the following claizzas and the legal equivalents thereof.
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