Note: Descriptions are shown in the official language in which they were submitted.
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LEAK DETECTION STRUCTURE
Background
Printing mechanisms may include a printhead for printing an image on a media.
One
or more inks are usually supplied to the printhead from one or more ink
reservoirs.
Unfortunately, if ink leaks from an ink reservoir it may harm components
within the
printing mechanism. Certain printing mechanisms therefore include a sensor
that is
positioned within the printing mechanism to detect an ink leak and in response
alert the user
in some manner.
Summary
Accordingly, in one aspect there is provided an ink supply, comprising:
an ink sensor; and
a capillary structure positioned adjacent said ink sensor, said capillary
structure
defining a capillary ink path onto said sensor.
According to another aspect of the present invention there is provided a leak
detection structure, comprising:
a sensor including a planar leak detection surface; and
a wicking structure positioned adjacent said planar leak detection surface,
said
wicking structure adapted for wicking a fluid into contact with said planar
leak detection
surface.
According to yet another aspect there is provided a leak detection structure,
comprising:
a sensor including a leak detection surface; and
a wicking structure positioned adjacent said leak detection surface, said
wicking
structure adapted for wicking a fluid into contact with said leak detection
surface,
wherein said wicking structure includes a wicking surface spaced from said
leak
detection surface so as to define therebetween a wicking path for said fluid.
According to yet another aspect there is provided a leak detection structure,
comprising:
a sensor including a leak detection surface; and
a wicking structure positioned adjacent said leak detection surface, said
wicking
structure adapted for wicking a fluid into contact with said leak detection
surface, wherein
said leak detection surface comprises first and second contact pads, and
wherein said
wicking structure is adapted for wicking a fluid simultaneously onto said
first
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and second contact pads so as to define a conductivity path between said pads
and through
said fluid.
According to yet another aspect there is provided a leak detection structure,
comprising:
a sensor including a leak detection surface; and
a wicking structure positioned adjacent said leak detection surface, said
wicking
structure adapted for wicking a fluid into contact with said leak detection
surface, wherein
said wicking structure comprises an absorbent material positioned in contact
with said leak
detection surface, said absorbent material adapted for absorbing said fluid
therein and being
chosen from the group consisting of foam, woven fiber, plastic fiber.
According to still yet another aspect of the present invention there is
provided a leak
detection structure, comprising:
a sensor including a leak detection surface; and
a wicking structure positioned adjacent said leak detection surface, said
wicking
structure adapted for wicking a fluid along only a vertical path and into
contact with said
leak detection surface.
Brief Description of the Drawings
FIG. I is a schematic view of one embodiment of a printing mechanism that
includes an exemplary leak detection structure in accordance with an
embodiment of the
present invention.
FIG. 2 is a partial cross-sectional side view of an exemplary embodiment of an
ink
supply including an exemplary leak detection structure in accordance with an
embodiment
of the present invention.
FIG. 3 is a detailed perspective view of the exemplary leak detection
structure
shown in FIG. 2.
FIG. 4 is a partial cross-sectional side view of the exemplary leak detection
structure shown in FIG. 2.
FIG. 5 is a partial cross-sectional side view of another exemplary leak
detection
structure in accordance with another embodiment of the present invention.
FIG. 6 is a partial cross-sectional side view of another exemplary leak
detection
structure in accordance with yet another embodiment of the present invention.
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Detailed Description of the Drawings
FIG. 1 is a schematic view of one embodiment of a printing mechanism 10 for
printing an image on one embodiment of a media 12. Printing mechanism 10 may
be a
printer, a copier, a facsimile machine, a camera or the like, any combination
thereof, or
any device suitable for imaging. Media 12 may include paper, fabric, mylar,
transparency foils, cardboard, or any other medium suitable for imaging
thereon.
Printing mechanism 10 includes a print cartridge 14 for printing an image on
media 12.
Print cartridge 14 is operatively connected to an ink supply 16, such as, for
example, by
a connection tube 18 or the like. In this manner, ink contained within ink
supply 16 can
then be delivered to print cartridge 14. A sensor 19 is positioned within
printing
mechanism 10 so as to detect a leakage of ink from ink supply 16. Sensor 19
may be
operatively connected to a controller 20 wherein controller 20 may activate a
notification device 22, such as a visual or an audible alert device, which may
alert a user
that an ink leak has occurred. Controller 20 may also function to shut down
operation of
printing mechanism 10 if a leak is detected.
FIG. 2 is a partial cross-sectional side view of one embodiment of ink supply
16.
In this example, ink supply 16 includes a chassis 24 that is connected to a
first ink
container 26, such as a flexible ink container or a bag (shown in a small size
for ease of
illustration), and a second ink container 28, such as a rigid container or a
bottle. Bag 26
is secured on an upwardly extending projection 30 of chassis 24, which
includes a
support fin 30a, wherein an interior 32 of bag 26 and an interior 34 of
projection 30 are
in fluidic communication with connection tube 18 (see FIG. 1), and therefore,
in
connection with print cartridge 14 (see FIG. 1). In this manner, ink 36
contained within
bag 26 is delivered to print cartridge 14. In the embodiment shown, bag 26 is
"heat
staked," e.g., welded or heat sealed, to projection 30 and fin 30a along a
heat sealing
region 26a of bag 26.
As further illustrated in the example in Fig. 2, ink supply 16 includes an ink
reservoir 38 that is defined by an upwardly extending wall 40 that extends
around a
perimeter 42 of chassis 24. Ink reservoir 38 is structured to retain at least
a portion of
ink that leaks from bag 26. Here, leaking ink will likely flow downwardly into
ink
reservoir 38 by the force of gravity. The leaking ink may also flow downwardly
as a
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result of air pressure or the like. Wall 40 includes a securement structure,
such as an
outwardly extending ridge 44, that is utilized to retain bottle 28 thereon. In
the
exemplary embodiment shown, bottle 28 is secured to chassis 24, with an
intervening o-
ring 45, by a clamp ring 47 positioned therearound.
Bag 26 is secured on chassis 24 and inside bottle 28. Bottle 28 with bag 26
therein, therefore, functions as a double wall ink supply container which may
function to
reduce ink leakage to the outside of bottle 28. Accordingly, such a double
wall ink
supply container may limit ink damage to components of printing mechanism 10
that
may be positioned outside of bottle 28. Damage to components of printing
mechanism
10 (see FIG. 1) may also be reduced by positioning a sensor within bottle 28
so as to
detect an ink leaked from bag 26, before the ink leaks from bottle 28.
Ink supply 16 further includes sensor 19 which, in this example, is secured on
chassis 24 outside of bag 26 and inside of bottle 28. Sensor 19 is configured
to detect
the presence of ink. As such, sensor 19 and/or operative components of sensor
19 are
positioned within ink reservoir 38 such that if ink leaks from bag 26 and
flows
downwardly into ink reservoir 38 it is detected. When sensor 19 detects the
presence of
leaked ink it notifies or otherwise signals controller 20 or other like
circuitry (see FIG.
1). In Fig. 2, sensor 19 includes as operative components first and second
contact pads
50 and 52, respectively, that are positioned nearby or adjacent one another.
In this
embodiment, pads 50 and 52 each define a detection surface 54 and 56,
respectively. In
the embodiment shown, detection surfaces 54 and 56 are gold contact pads.
Detection
surfaces 54 and 56 may be positioned in a plane 58 (e.g., as shown in end view
in FIG.
4) that is perpendicular to a plane 60 of a base 62 of chassis 24. In the
exemplary
embodiment sensor 19 is a flexible circuit including a plurality of traces
that are in
electrical contact with detection surfaces 54 and 56 such that an electrical
conductivity
between surfaces 54 and 56 may be signaled to controller 20.
Sensor 19 is configured to measure or otherwise detect changes in one or more
electrical parameters using detection surfaces 54 and 56. The electrical
parameters will
change in some manner when leaked ink contacts detection surfaces 54 and/or
56. The
measured/detected electrical parameters may include resistance, impedance,
capacitance, etc.
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For example, in a nominal, non-leak state, detection surfaces 54 and 56 would
be
in contact with air. Accordingly, sensor 19 will detect an electrical
parameter associated
with the air. For example, sensor 19 may measure the resistance between
detection
surfaces 54 and 56 through the air. If the measured resistance is above a
predetermined
threshold level, such as a resistance level of about 8 mega ohms, then a "no
leak"
condition may be reported to controller 20 (see FIG. 1). In a leak state, for
example,
both of detection surfaces 54 and 56 may be in contact with leaked ink which
may
provide a conductivity path between surfaces 54 and 56. The ink may have a
lower
electrical resistance value than air, which may be at or below a predetermined
threshold
level, such as at a resistance level of about 6 mega ohms or lower, such that
a "leak"
condition may be detected by controller 20. The predetermined threshold
measurement
level may be set at any value desired and in some embodiments, may be varied
during
use.
Still referring to FIG. 2, ink supply 16 may further include a leak detection
structure 64 that may be positioned adjacent to or in contact with sensor 19.
Leak
detection structure 64 is configured to function to move ink leaked into ink
reservoir 38
upwardly onto, and to retain the ink on, detection surfaces 54 and 56 of
sensor 19. In
the embodiment shown in FIG. 2, leak detection structure 64 includes a first
rib 66
positioned adjacent first detection surface 54 and a second rib 68 positioned
adjacent
second detection surface 56. Ribs 66 and 68 may be spaced from detection
surfaces 54
and 56, respectively, a predetermined distance, as will be described in more
detail
below. Ribs 66 and 68, therefore, may define a wicking and/or a capillary
structure
such that ink retained in ink reservoir 38 may be moved by wicking and/or
capillary
action upwardly between ribs 66 and 68 and detection surfaces 54 and 56,
respectively,
and into contact with detection surfaces 54 and 56.
FIGS. 3 and 4 are a detailed perspective view and a partial cross-sectional
side
view, respectively, of leak detection structure 64 shown in FIG. 2. In this
embodiment,
ribs 66 and 68 extend upwardly from a base 70 of leak detection structure 64,
wherein
base 70 is positioned against a lower region 72 of sensor 19. Each of ribs 66
and 68
may include a wicking surface 74 and 76, respectively, positioned adjacent to
and
spaced from each of detection surfaces 54 and 56, respectively. In the
embodiment
shown, wicking surfaces 74 and 76 may be inclined with respect to plane 58 so
as to
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define an angle 77 therebetween. Angle 77 may be any angle suited for a
particular
sensor or detection surface. In the exemplary embodiment shown, angle 77 is
about 15
degrees. In other embodiments, angle 77 may be a low as zero degrees, i.e.,
parallel to
the detection surfaces, about five degrees from the detection surfaces, and as
high or
higher than about thirty degrees. In another embodiment, one or both of
wicking
surface 74 and 76 are inclined with respect to plane 58 such that an upper
region of the
wicking surfaces may be closer to plane 58 than a lower region of wicking
surface 74
and 76. In still another embodiment, plane 58 of detection surfaces 54 and 56
are
inclined with respect to a vertical plane.
Wicking surfaces 74 and 76 may be spaced from detection surfaces 54 and 56,
respectively, a distance 78 in a lower region of surfaces 74 and 76, and may
be spaced
from detection surfaces 54 and 56, respectively, a distance 80 in an upper
region of
surfaces 74 and 76. Distances 78 and 80 may be any distance or spacing
sufficient to
facilitate movement of ink 36 (see FIG. 2) upwardly between wicking surfaces
74 and
76 and detection surfaces 54 and 56, respectively, by capillary or surface
tension forces.
Accordingly, distances 78 and 80 may vary from one printing mechanism to
another
based on the surface tension properties of ink 36 (see FIG. 2) contained
within ink
supply 16 (see FIG. 1), and which may leak into ink reservoir 38 of chassis 24
(see FIG.
2). In the exemplary embodiment shown, wherein ink 36 (see FIG. 2) includes
inkjet
ink suited for printing on a sheet of paper, distances 78 and 80 may be in a
range of zero
to about 20 millimeters. In certain embodiments, distances 78 and 80 are less
than about
5 millimeters.
Due to the wicking properties of leak detection structure 64, once ink rises
to a
level 82 within ink reservoir 38, the ink may be moved by capillary and/or
wicking
action upwardly in direction 84 between wicking surfaces 74 and 76 and
detection
surfaces 54 and 56, respectively, to a height 86, for example, such that a
conductivity
path is created between detection surfaces 54 and 56 through the ink, thereby
allowing
sensor 19 to detect the presence of leaked ink. In other embodiments, level 82
may be
contiguous with a floor 92 of ink reservoir 38, or may be positioned at any
level as
desired.
The space between wicking surfaces 74 and 76 and detection surfaces 54 and 56,
respectively, may be referred to as a wicking and/or capillary path 90. Here,
path 90 has
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a width 94 that may be sufficient to allow ink 36 (see FIG. 2) to move
upwardly along
path 90 and simultaneously onto detection surfaces 54 and 56 by capillary
action and/or
surface tension forces. Moreover, width 94 may be sufficient to retain ink 36
(see FIG.
2) within path 90 due to capillary and/or surface tension forces. In the
embodiment
shown in FIGS. 3 and 4, width 94 of path 90 varies from distance 78 in a lower
region
of detection surfaces 54 and 56 to distance 80 in an upper region of detection
surface 54
and 56. Due to leak detection structure 64 positioned adjacent to or in
contact with
detection surfaces 54 and 56, an ink leak is detected prior to ink reservoir
38 filling
completely to a level as high as detection surfaces 54 and 56, such as a level
88. The
difference in a volume of ink at level 82 and a volume of ink at level 88
within ink
reservoir 38 can be quite large, such that incorporation of ink detection
structure 64 in
printing mechanism 10 (see FIG. 1) may significantly reduce the amount of ink
present
in ink reservoir 38 before a leak may be detected. Thus, incorporation of ink
detection
structure 64 in printing mechanism 10 (see FIG. 1) tends to significantly
reduce the
amount of time that may pass from an initial leak before a leak may be
detected.
By way of example, in one test case, wherein ink detection structure 64 was
not
incorporated in printing mechanism 10, ink was detected by sensor 19 when 2.6
cubic
centimeters (cc) of ink, was leaked from bag 26. After incorporation of leak
detection
structure 64 into printing mechanism 10 adjacent sensor 19, ink was detected
by sensor
19 when 0.6 cc of ink was leaked from bag 26. Accordingly, leak detection
structure 64
may allow detection of a leak upon leakage of a significantly smaller amount
of ink than
devices that do not include ink detection structure 64. Detection of a leak at
an earlier
time, i.e., after leakage of a lesser amount of ink, may result in
preventative measures
being taken at an earlier time, thereby potentially reducing damage to
printing
mechanism 10.
FIG. 5 is a side view of another embodiment of a leak detection structure 64.
In
this embodiment, leak detection structure 64 includes a solid wall 96 and
sensor 19
includes a pair of detection surfaces 98. In this embodiment, wall 96 may
define a
wicking surface 100 that may define a plane 102 (seen in side view) that may
be parallel
to a plane 104 (seen in side view) of pair of detection surfaces 98. Wall 96
may be
spaced from sensor 19 and from pair of detection surfaces 98 by a spacing 106,
wherein
spacing 106 may extend downwardly to floor 92 of chassis 24 and ink reservoir
38.
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Accordingly, an ink wicking pathway 108 extends upwardly directly from floor
92 of
chassis 24. Ink leaked into ink reservoir 38 (see FIG. 2), therefore, may
quickly come
into contact with pathway 108 such that even a very small amount of leaked ink
may
generate a volume of ink sufficient to be wicked along pathway 108 to as to
allow
detection of the ink leak by sensor 19 and controller 20 (see FIG. 1).
FIG. 6 is a side view of another embodiment of a leak detection structure 64.
In
this embodiment, leak detection structure 64 includes a wicking material, such
as an
absorbent material 110 that extends upwardly from floor 92 of chassis 24 and
is
positioned adjacent to and in contact with pair of detection surfaces 98 of
sensor 19. In
this embodiment, a wicking and/or capillary pathway 112 of ink 36 (see FIG. 2)
may
extend through absorbent material 110 itself. Absorbent material 110 may, for
example,
include an open cell foam or any other type of material that may facilitate
ink being
drawn into and upwardly within the material so as to come into contact with
detection
surfaces 98 of sensor 19. Absorbent material 110 may include a foam, a woven
fiber, a
plastic fiber, or the like. In this embodiment, ink is draw upwardly and into
contact with
pair of detection surfaces 98 so as to define a conductivity pathway
therebetween that
may be sensed by controller 20 (FIG. 1). In an absence of ink within absorbent
material
110, sensor 20 detects a conductivity of air between pair of detection
surfaces 98.
Similar to the ink wicking pathway 90 of FIG. 4 and pathway 108 of FIG. 5,
absorbent material 110 provides wicking pathway 112 through which ink moves by
a
wicking action. Accordingly, in the exemplary embodiments shown, ink moves
upwardly through an air space, such, as pathway 90 (FIG. 4), 108 (FIG. 5) or
112 (FIG.
6) and into contact with a detection surface, wherein the pathway is defined
by an
upwardly extending structure positioned near or adjacent to the detection
surfaces.
The scope of the claims should not be limited by the preferred embodiments set
forth in the examples, but should be given the broadest interpretation
consistent with
the description as a whole.
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