Method for refilling an ink supply for an ink-jet printer

The ink supply has an ink reservoir, a valve, a pressurizable chamber, and an outlet. The refilling is accomplished by directing ink from the outlet into the reservoir while the chamber is otherwise unpressurized so that the valve remains slightly open to permit the refill flow therethrough.

BACKGROUND AND SUMMARY OF THE INVENTION 
The present invention relates to a method for refilling a reusable ink 
supply having a pressurized chamber. 
A typical ink-jet printer has a pen mounted to a carriage that traverses a 
printing surface, such as a piece of paper. The pen carries a print head. 
As the print head passes over appropriate locations on the printing 
surface, a control system activates ink-jets on the print head to eject, 
or jet, ink drops onto the printing surface and form desired images and 
characters. 
To work properly, such printers must have a reliable supply of ink for the 
print head. Many ink-jet printers use a disposable ink pen that can be 
mounted to the carriage. Such an ink pen typically includes, in addition 
to the print head, a reservoir containing a supply of ink. The ink pen 
also typically includes pressure regulating mechanisms to maintain the ink 
supply at an appropriate pressure for use by the print head. When the ink 
supply is exhausted, the ink pen is disposed of and a new ink pen is 
installed. This system provides an easy, user friendly way of providing an 
ink supply for an ink-jet printer. 
However, in a printer using an ink pen, the entire ink pen, including the 
reservoir and ink supply, is moved with the print head. This requires a 
trade-off. If the ink pen has a large reservoir and ink supply, it is 
heavier and is more difficult to move quickly. This may limit the speed 
with which the printer can print--an important characteristic of a 
printer. On the other hand, if the ink pen has a small reservoir and ink 
supply, it will be depleted more quickly and require more frequent 
replacement. 
The problems posed by size limitations of the ink reservoir have been 
heightened by the increasing popularity of color printers. In a color 
printer, it is usually necessary to supply more than one color of ink to 
the print head. Commonly, three or four different ink colors, each of 
which must be contained in a separate reservoir, are required. The 
combined volume of all of these reservoirs is limited in the same manner 
as the single reservoir of a typical one-color printer. Thus, each 
reservoir can be only a fraction of the size of a typical reservoir for a 
one-color printer. 
Furthermore, when even one of the reservoirs is depleted, the ink pen may 
no longer be able to print as intended. Thus, the ink pen must typically 
be replaced and discarded, or at least removed for refilling, when the 
first of the reservoirs is exhausted. This further decreases the useful 
life of the ink pen. 
As can be appreciated, the print head and pressure regulating mechanism of 
the ink pen contribute substantially to the cost of the ink pen. These 
mechanisms can also have a useful life expectancy far longer than the 
supply of ink in the reservoir. Thus, when the ink pen is discarded, the 
print head and pressure regulating mechanisms may have a great deal of 
usable life remaining. In addition, in multiple color ink pens, it is 
unlikely that all of the ink reservoirs will be depleted at the same time. 
Thus, the discarded ink pen will likely contain unused ink as well as a 
fully functional print head and pressure regulating mechanism. This 
results in increased cost to the user and a somewhat wasteful and 
inefficient use of resources. 
To alleviate some of the shortcomings of disposable ink pens, some ink-jet 
printers have used ink supplies that are not mounted to the carriage. Such 
ink supplies, because they are stationary within the printer, are not 
subject to all of the size limitations of an ink supply that is moved with 
the carriage. Some printers with stationary ink supplies have a refillable 
ink reservoir built into the printer. Ink is supplied from the reservoir 
to the print head through a tube which trails from the print head. 
Alternatively, the print head can include a small ink reservoir that is 
periodically replenished by moving the print head to a filling station at 
the stationary, built-in reservoir. In either alternative, ink may be 
supplied from the reservoir to the print head by either a pump within the 
printer or by gravity flow. 
However, such built-in reservoirs are frequently difficult and messy to 
refill. In addition, because they are never replaced, built-in ink 
reservoirs tend to collect particles and contaminants that can adversely 
affect printer performance. 
In view of these problems, some printers use replaceable reservoirs. These 
reservoirs, like the built-in reservoirs are not located on the carriage 
and, thus, are not moved with the print head during printing. Replaceable 
reservoirs sometimes are plastic bags filled with ink. The bag is provided 
with a mechanism, such as a septum which can be punctured by a hollow 
needle, for coupling it to the printer so that ink may flow from the bag 
to the print head. Often, the bag is squeezed, or pressurized in some 
other manner, to cause the ink to flow from the reservoir. Should the bag 
burst or leak while under pressure, the consequences can be catastrophic 
for the printer. 
One particular replaceable reservoir reliably supplies ink to the print 
head, yet is not complicated and can be manufactured simply and 
inexpensively. This reservoir is also easily recyclable. 
The replaceable reservoir has an ink supply that has a main reservoir for 
holding a supply of ink. The main reservoir, which is typically maintained 
at about ambient pressure, is coupled to a variable volume chamber via a 
valve that allows the flow of ink from the reservoir to the chamber and 
limits the flow of ink from the chamber to the reservoir. The chamber is 
coupled to a fluid outlet which is normally closed to prevent the flow of 
ink. However, when the ink supply is installed in a printer, the fluid 
outlet opens to establish a fluid connection between the chamber and the 
pen. 
The chamber can serve as part of a pump to supply ink from the reservoir to 
the pen. In particular, when the volume of the chamber is increased, ink 
is drawn from the reservoir through the valve and into the chamber. When 
the volume of the chamber is decreased, ink is forced from the chamber 
through the fluid outlet to supply the print head. 
The reservoir includes flexible plastic walls supported by a rigid frame. 
The frame is carried by a chassis which also carries the variable volume 
chamber and the fluid outlet. 
The present invention is particularly directed to a method for refilling an 
ink supply of the type described above. This allows the ink supply 
container to be reused. 
The present method involves supplying refill ink into the ink supply 
container through the fluid outlet that otherwise, during normal 
operation, serves to direct the ink from the supply to the pen. 
Other objects and aspects of the invention will become apparent to those 
skilled in the art from the detailed description of the invention which is 
presented by way of example and not as a limitation of the present 
invention.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS 
An ink supply in accordance with a preferred embodiment of the present 
invention is illustrated in FIG. 1 as reference numeral 20. The ink supply 
20 has a chassis 22 which carries an ink reservoir 24 for containing ink, 
a pump 26 and fluid outlet 28. The chassis 22 is enclosed within a hard 
protective shell 30 having a cap 32 affixed to its lower end. The cap 32 
is provided with an aperture 34 to allow access to the pump 26 and an 
aperture 36 to allow access to the fluid outlet 28. 
In use, the ink supply 20 is inserted into the docking bay 38 of an ink-jet 
printer, as illustrated in FIGS. 9 and 10. Upon insertion of the ink 
supply 20, an actuator 40 within the docking bay 38 is brought into 
contact with the pump 26 through aperture 34. In addition, a fluid inlet 
42 within the docking bay 38 is coupled to the fluid outlet 28 through 
aperture 36 to create a fluid path from the ink supply 20 to the pen. 
Operation of the actuator 40 causes the pump 26 to draw ink from the 
reservoir 24 and supply the ink through the fluid outlet 28 and the fluid 
inlet 42 to the pen. 
Upon depletion of the ink from the reservoir 24, or for any other reason, 
the ink supply 20 can be easily removed from the docking bay 38. Upon 
removal, the fluid outlet 28 and the fluid inlet 42 close to help prevent 
any residual ink from leaking into the printer or onto the user. The ink 
supply 20 may then be refilled, discarded or stored for reinstallation at 
a later time. In this manner, the ink supply 20 provides a user of an 
ink-jet printer a simple, economical way to provide a reliable, and easily 
replaceable, supply of ink to an ink-jet printer. 
As illustrated in FIGS. 1-3, the chassis 22 has a main body 44. Extending 
upward from the top of the chassis body 44 is a frame 46 which helps 
define and support the ink reservoir 24. In the illustrated embodiment, 
the frame 46 defines a generally square reservoir 24 having a thickness 
determined by the thickness of the frame 46 and having open sides. Each 
side of the frame 46 is provided with a face 48 to which a sheet of 
plastic 50 is attached to enclose the sides of the reservoir 24. The 
illustrated plastic sheet is flexible to allow the volume of the reservoir 
24 to vary as ink is depleted from the reservoir 24. This helps to allow 
withdrawal and use of all of the ink within the reservoir 24 by reducing 
the amount of backpressure created as ink is depleted from the reservoir 
24. The illustrated ink supply 20, is intended to contain about 30 cubic 
centimeters of ink when full. Accordingly, the general dimensions of the 
ink reservoir defined by the frame are about 57 mm high, about 60 mm wide, 
and about 5.25 mm thick. These dimensions may vary depending on the 
desired size of the ink supply and the dimensions of the printer in which 
the ink supply is to be used. 
In the illustrated embodiment, the plastic sheets 50 are heat staked to the 
faces 48 of the frame in a manner well known to those in the art. The 
plastic sheets 50 are, in the illustrated embodiment, multi-ply sheets 
having a an outer layer of low density polyethylene, a layer of adhesive, 
a layer of metallized polyethylene terephthalate, a layer of adhesive, a 
second layer of metallized polyethylene terephthalate, a layer of 
adhesive, and an inner layer of low density polyethylene. The layers of 
low density polyethylene are about 0.0005 inches thick and the metallized 
polyethylene terephthalate is about 0.00048 inches thick. The low density 
polyethylene on the inner and outer sides of the plastic sheets can be 
easily heat staked to the frame while the double layer of metallized 
polyethylene terephthalate provides a robust barrier against vapor loss 
and leakage. Of course, in other embodiments, different materials, 
alternative methods of attaching the plastic sheets to the frame, or other 
types of reservoirs might be used. 
The body 44 of the chassis 22, as seen in FIGS. 1-4, is provided with a 
fill port 52 to allow ink to be introduced into the reservoir 24. After 
filling the reservoir 24, a plug 54 is inserted into the fill port 52 to 
prevent the escape of ink through the fill port 52. In the illustrated 
embodiment, the plug 54 is a polypropylene ball that is press fit into the 
fill port 52. 
A pump 26 is also carried on the body 44 of the chassis 22. The pump 26 
serves to pump ink from the reservoir 24 and supply it to the printer via 
the fluid outlet 28. In the illustrated embodiment, seen in FIGS. 1 and 2, 
the pump 26 includes a pump chamber 56 that is integrally formed with the 
chassis 22. The pump chamber 56 is defined by a skirt-like wall 58 which 
extends downwardly from the body 44 of the chassis 22. 
A pump inlet 60 is formed at the top of the chamber 56 to allow fluid 
communication between the chamber 56 and the ink reservoir 24. A pump 
outlet 62 through which ink may be expelled from the chamber 56 is also 
provided. A valve 64 is positioned within the pump inlet 60. The valve 64 
allows the flow of ink from the ink reservoir 24 into the chamber 56 but 
limits the flow of ink from the chamber 56 back into the ink reservoir 24. 
In this way, when the chamber is depressurized, ink may be drawn from the 
ink reservoir 24, through the pump inlet and into the chamber and when the 
chamber is pressurized ink within the chamber may be expelled through the 
pump outlet. In the illustrated embodiment, the valve 64 is a flapper 
valve positioned at the bottom of the pump inlet 60. The flapper valve 64, 
illustrated in FIGS. 1 and 2, is a rectangular piece of flexible material. 
The valve 64 is positioned over the bottom of the pump inlet 60 and heat 
staked to the chassis 22 at the midpoints of its short sides (the heat 
staked areas are darkened in the Figures). When the pressure within the 
chamber 56 drops sufficiently below that in the reservoir 24, the unstaked 
sides of the valve 64 each flex downward to allow the flow of ink around 
the valve 64, through the pump inlet 60, and into the chamber 56. The 
valve 64 is configured to remain open as long as the chamber 56 is not 
pressurized. In alternative configurations, the flapper valve 64 could be 
heat staked on only one side so that the entire valve 64 would flex about 
the staked side, or on three sides so that only one side of the valve 64 
would flex. 
In the illustrated embodiment, the flapper valve 64 is made of a two ply 
material. The top ply is a layer of low density polyethylene 0.0015 inches 
thick. The bottom ply is a layer of polyethylene terephthalate (PET) 
0.0005 inches thick. The illustrated flapper valve 64 is approximately 5.5 
millimeters wide and 8.7 millimeters long. Of course, other materials or 
other sizes of valves may be used. 
A flexible diaphragm 66 encloses the bottom of the chamber 56. The 
diaphragm 66 is slightly larger than the opening at the bottom of the 
chamber 56 and is sealed around the bottom edge of the wall 58. The excess 
material in the oversized diaphragm 66 allows the diaphragm 66 to flex up 
and down to vary the volume within the chamber 56. In the illustrated ink 
supply 20, displacement of the diaphragm 66 allows the volume of the 
chamber 56 to be varied by about 0.7 cubic centimeters. The fully expanded 
volume of the illustrated chamber 56 is between about 2.2 and 2.5 cubic 
centimeters. 
The illustrated diaphragm 66 is made of the same multi-ply material as the 
plastic sheets 50. Of course, other suitable materials may also be used to 
form the diaphragm 66. The diaphragm 66 in the illustrated embodiment is 
heat staked, using conventional methods, to the bottom edge of the 
skirt-like wall 58. During the heat staking process, the low density 
polyethylene in the diaphragm 66 seals any folds or wrinkles in the 
diaphragm 66 to create a leak proof connection. 
A pressure plate 68 and a spring 70 are positioned within the chamber 56. 
The pressure plate 68, illustrated in detail in FIGS. 5 and 6, has a 
smooth lower face 72 with a wall 74 extending upward about its perimeter. 
The central region 76 of the pressure plate 68 is shaped to receive the 
lower end of the spring 70 and is provided with a spring retaining spike 
78. Four wings 80 extend laterally from an upper portion of the wall 74. 
The illustrated pressure plate 68 is molded of high density polyethylene. 
The pressure plate 68 is positioned within the chamber 56 with the lower 
face 72 adjacent the flexible diaphragm 66. The upper end of the spring 
70, which is stainless steel in the illustrated embodiment, is retained on 
a spike 82 formed in the chassis and the lower end of the spring 70 is 
retained on the spike 78 on the pressure plate 68. In this manner, the 
spring biases the pressure plate 68 downward against the diaphragm 66 to 
increase the volume of the chamber. The wall 74 and wings 80 serve to 
stabilize the orientation of the pressure plate 68 while allowing for its 
free, piston-like movement within the chamber 56. 
An alternative embodiment of the pump 26 is illustrated in FIG. 7. In this 
embodiment, the pump 26 includes a chamber 56a defined by a skirt-like 
wall 58a depending downwardly from the body 44a of the chassis. A flexible 
diaphragm 66a is attached to the lower edge of the wall 58a to enclose the 
lower end of the chamber 56a. A pump inlet 60a at the top of the chamber 
56a extends from the chamber 56a into the ink reservoir 24a, and a pump 
outlet 62a allows ink to exit the chamber 56a. The pump inlet 60a has a 
wide portion 86 opening into the chamber 56a, a narrow portion 88 opening 
into the ink reservoir, and a shoulder 90 joining the wide portion 86 to 
the narrow portion 88. A valve 64a is positioned in the pump inlet 60a to 
allow the flow of ink into the chamber 56a and limit the flow of ink from 
the chamber 56 back into the ink reservoir 24a. In the illustrated 
embodiment, the valve is circular. However, other shaped valves, such as 
square or rectangular, could also be used. 
In the embodiment of FIG. 7, a unitary spring/pressure plate 92 is 
positioned within the chamber 56a. The spring/pressure plate 92 includes a 
flat lower face 94 that is positioned adjacent the diaphragm 66a, a spring 
portion 96 that biases the lower face downward, and a mounting stem 98 
that is friction fit into the wide portion 86 of the pump inlet 60a. In 
the illustrated embodiment, the spring portion 96 is generally circular in 
configuration and is pre-stressed into a flexed position by the diaphragm 
66a. The natural resiliency of the material used to construct the 
spring/pressure plate 92 urges the spring to its original configuration, 
thereby biasing the lower face downward to expand the volume of the 
chamber 56a. The unitary spring/pressure plate 92 may be formed of various 
suitable materials such as, for example, HYTREL. 
In this embodiment, the valve 64a is a flapper valve that is held in 
position on the shoulder 90 of the pump inlet 60a by the top of the 
mounting stem 98. The mounting stem 98 has a cross shape which allows the 
flapper valve 64a to deflect downward into four open quadrants to allow 
ink to flow from the ink reservoir 24a into the chamber. The shoulder 
prevents the flapper valve from deflecting in the upward direction to 
limit the flow of ink from the chamber back into the reservoir 24a. 
Rather, ink exits the chamber via the pump outlet 62. It should be 
appreciated that the mounting stem may have a "V" cross section, an "I" 
cross section, or any other cross section which allows the flapper valve 
to flex sufficiently to permit the needed flow of ink into the chamber. 
As illustrated in FIG. 2, a conduit 84 joins the pump outlet 62 to the 
fluid outlet 28. In the illustrated embodiment, the top wall of the 
conduit 84 is formed by the lower member of the frame 46, the bottom wall 
is formed by the body 44 of the chassis 22; one side is enclosed by a 
portion of the chassis and the other side is enclosed by a portion of one 
of the plastic sheets 50. 
As illustrated in FIGS. 1 and 2, the fluid outlet 28 is housed within a 
hollow cylindrical boss 99 that extends downward from the chassis 22. The 
top of the boss 99 opens into the conduit 84 to allow ink to flow from the 
conduit 84 into the fluid outlet 28. A spring 100 and sealing ball 102 are 
positioned within the boss 99 and are held in place by a compliant septum 
104 and a crimp cover 106. The length of the spring 100 is such that it 
can be placed into the inverted boss 99 with the ball 102 on top. The 
septum 104 can then inserted be into the boss 99 to compress the spring 
100 slightly so that the spring 100 biases the sealing ball 102 against 
the septum 104 to form a seal. The crimp cover 106 fits over the septum 
104 and engages an annular projection 108 on the boss 99 to hold the 
entire assembly in place. 
In the illustrated embodiment, both the spring 100 and the ball 102 are 
stainless steel. The sealing ball 102 is sized such that it can move 
freely within the boss 99 and allow the flow of ink around the ball 102 
when it is not in the sealing position. The septum 104 is formed of 
polyisoprene rubber and has a concave bottom to receive a portion of the 
ball 102 to form a secure seal. The septum 104 is provided with a slit 110 
(FIG. 1) so that it may be easily pierced without tearing or coring. 
However, the slit 110 is normally closed such that the septum 104 itself 
forms a second seal. The slit 110 may, preferably, be slightly tapered 
with its narrower end adjacent the ball 102. The illustrated crimp cover 
106 is formed of aluminum and has a thickness of about 0.020 inches. A 
hole 112 is provided so that the crimp cover 106 does not interfere with 
the piercing of the septum 104. 
With the pump and fluid outlet 28 in place, the ink reservoir 24 can be 
filled with ink. To fill the ink reservoir 24, ink can be injected through 
the fill port 52. As ink is being introduced into the reservoir 24, a 
needle (not shown) can be inserted through the slit 110 in the septum 104 
to depress the sealing ball 102 and allow the escape of any air from 
within the reservoir 24. Alternatively, a partial vacuum can be applied 
through the needle. The partial vacuum at the fluid outlet 28 causes ink 
from the reservoir 24 to fill the chamber 56, the conduit 84, and the 
cylindrical boss 99 such that little, if any, air remains in contact with 
the ink. The partial vacuum applied to the fluid outlet 28 also speeds the 
filling process. Once the ink supply 20 is filled, the plug 54 is press 
fit into the fill port 52 to prevent the escape of ink or the entry of 
air. 
Of course, there are a variety of other methods which might also be used to 
fill the present ink supply 20. In some instances, it may be desirable to 
flush the entire ink supply 20 with carbon dioxide prior to filling it 
with ink. In this way, any gas trapped within the ink supply 20 during the 
filling process will be carbon dioxide, not air. This may be preferable 
because carbon dioxide may dissolve in some inks while air may not. In 
general, it is preferable to remove as much gas from the ink supply 20 as 
possible so that bubbles and the like do not enter the print head or the 
trailing tube. To this end, it may also be preferable to use degassed ink 
to further avoid the creation or presence of bubbles in the ink supply 20. 
Although the ink reservoir 24 provides an ideal way to contain ink, it may 
be easily punctured or ruptured and may allow some amount of water loss 
from the ink. Accordingly, to protect the reservoir 24 and to further 
limit water loss, the reservoir 24 is enclosed within a protective shell 
30. The illustrated shell 30 is made of clarified polypropylene. A 
thickness of about one millimeter has been found to provide robust 
protection and to prevent unacceptable water loss from the ink. However, 
the material and thickness of the shell 30 may vary in other embodiments. 
As illustrated in FIG. 1, the top of the shell 30 has contoured gripping 
surfaces 114 that are shaped and textured to allow a user to easily grip 
and manipulate the ink supply 20. A vertical rib 116 having a detente 118 
formed near its lower end projects laterally from each side of the shell 
30. The base of the shell 30 is open to allow insertion of the chassis 22. 
A stop 120 extends laterally outward from each side of wall 58 that 
defines the chamber 56. These stops 120 abut the lower edge of the shell 
30 when the chassis 22 is inserted. 
The protective cap 32 is fitted to the bottom of the shell 30 to maintain 
the chassis 22 in position. The cap 32 is provided with recesses 128 which 
receive the stops 120 on the chassis 22. In this manner, the stops 120 are 
firmly secured between the cap 32 and the shell 30 to maintain the chassis 
22 in position. The cap 32 is also provided with an aperture 34 to allow 
access to the pump 26 and with an aperture 36 to allow access to the fluid 
outlet 28. The cap 32 obscures the fill port 52 to help prevent tampering 
with the ink supply 20. 
One end of the cap 32 is provided with projecting keys 130 which can 
identify the type or "family" of ink contained within the ink supply 20. 
For example, if the ink supply 20 is filled with ink suited for use with a 
particular printer or class of printers, a cap having keys of a selected 
number and spacing (in the illustrated embodiment, three evenly spaced 
apart keys are shown) to indicate that ink family is used. 
The other end of the cap 32 is provided with a keyway 131 that, depending 
upon its particular location, size or both, is indicative of a certain 
color of ink, such as cyan, magenta, etc. Accordingly, if the ink supply 
20 is filled with a particular color of ink, a cap having keyway(s) 
indicative of that color may be used. The color of the cap may also be 
used to indicate the color of ink contained within the ink supply 20. 
As a result of this structure, the chassis 22 and shell 30 can be 
manufactured and assembled without regard to the particular type of ink 
they will contain. Then, after the ink reservoir 24 is filled, a cap 
indicative of the particular family and color of ink used is attached to 
the shell 30. This allows for manufacturing economies because a supply of 
empty chassis and shell 30 can be stored in inventory. Then when there is 
a demand for a particular type of ink, that ink can be introduced into the 
ink supply 20 and an appropriate cap fixed to the ink supply 20. Thus, 
this scheme reduces the need to maintain high inventories of ink supplies 
containing every type of ink. 
As illustrated, the bottom of the shell 30 is provided with two 
circumferential grooves 122 which engage two circumferential ribs 124 
formed on the cap 32 to secure the cap 32 to the shell 30. Sonic welding 
or some other mechanism may also be desirable to more securely fix the cap 
32 to the shell 30. In addition, a label can be adhered to both the cap 32 
and the shell 30 to more firmly secure them together. Pressure sensitive 
adhesive may be used to adhere the label in a manner that prevents the 
label from being peeled off and inhibits tampering with the ink supply 20. 
The attachment between the shell 30 and the cap 32 should, preferably, be 
snug enough to prevent accidental separation of the cap 32 from the shell 
30 and to resist the flow of ink from the shell 30 should the ink 
reservoir 24 develop a leak. However, it is also desirable that the 
attachment allow the slow ingress of air into the shell 30 as ink is 
depleted from the reservoir 24 to maintain the pressure inside the shell 
30 generally the same as the ambient pressure. Otherwise, a negative 
pressure may develop inside the shell 30 and inhibit the flow of ink from 
the reservoir 24. The ingress of air should be limited, however, in order 
to maintain a high humidity within the shell 30 and minimize water loss 
from the ink. 
The illustrated shell 30, and the flexible reservoir 24 which it contains, 
have the capacity to hold approximately thirty cubic centimeters of ink. 
The shell 30 is approximately 67 millimeters wide, 15 millimeters thick, 
and 60 millimeters high. Of course, other dimensions and shapes can also 
be used depending on the particular needs of a given printer. 
The illustrated ink supply 20 is ideally suited for insertion into a 
docking station 132 like that illustrated in FIGS. 8-10. The docking 
station 132 illustrated in FIG. 8, is intended for use with a color 
printer. Accordingly, it has four side-by-side docking bays 38, each of 
which can receive one ink supply 20 of a different color. The structure of 
the illustrated ink supply 20 allows for the supply to be relatively 
narrow in width. This allows for four ink supplies to be arranged 
side-by-side in a compact docking station without unduly increasing the 
"footprint" of the printer. 
Each docking bay 38 includes opposing walls 134 and 136 which define 
inwardly facing vertical channels 138 and 140. A leaf spring 142 having an 
engagement prong 144 is positioned within the lower portion of each 
channel 138 and 140. The engagement prong 144 of each leaf spring 142 
extends into the channel toward the docking bay 38 and is biased inward by 
the leaf spring. One of the channels 138 is provided with keys 139 formed 
therein to mate with the keyway(s) 131 on one side of the ink supply cap 
32. The other channel 140 is provided with keyways 141 to mate with the 
keys 130 on the other side of the cap 32. 
A base plate 146 defines the bottom of each docking bay 38. The base plate 
146 includes an aperture 148 which receives the actuator 40 and carries a 
housing 150 for the fluid inlet 42. 
As illustrated in FIG. 8, the upper end of the actuator extends upward 
through the aperture 148 in the base plate 146 and into the docking bay 
38. The lower portion of the actuator 40 is positioned below the base 
plate and is pivotably coupled to one end of a lever 152 which is 
supported on pivot point 154. The other end of the lever 154 is biased 
downward by a compression spring 156. In this manner, the force of the 
compression spring 156 urges the actuator 40 upward. A cam 158 mounted on 
a rotatable shaft 160 is positioned such that rotation of the shaft 160 to 
an engaged position causes the cam 158 to overcome the force of the 
compression spring 156 and move the actuator 40 downward. Movement of the 
actuator 40, as explained in more detail below, causes the pump 26 to draw 
ink from the reservoir 24 and supply it through the fluid outlet 28 and 
the fluid inlet 42 to the printer. 
As seen in FIG. 9, the fluid inlet 42 is positioned within the housing 150 
carried on the base plate 146. The illustrated fluid inlet 42 includes an 
upwardly extending needle 162 having a closed blunt upper end 164, a blind 
bore 166 and a lateral hole 168. A trailing tube (not shown) is connected 
to the lower end of the needle 162 such that the blind bore 166 is in 
fluid communication therewith. The trailing tube leads to a print head 
(not shown). In most printers, the print head will usually include a small 
ink well for maintaining a small quantity of ink and some type of pressure 
regulator to maintain an appropriate pressure within the ink well. 
Typically, it is desired that the pressure within the ink well be slightly 
less than ambient. This "back pressure" helps to prevent ink from dripping 
from the print head. The pressure regulator at the print head may commonly 
include a check valve which prevents the return flow of ink from the print 
head and into the trailing tube. 
A sliding collar 170 surrounds the needle 162 and is biased upwardly by a 
spring 172. The sliding collar 170 has a compliant sealing portion 174 
with an exposed upper surface 176 and an inner surface 178 in direct 
contact with the needle 162. In addition, the illustrated sliding collar 
includes a substantially rigid portion 180 extending downwardly to 
partially house the spring 172. An annular stop 182 extends outward from 
the lower edge of the substantially rigid portion 180. The annular stop 
182 is positioned beneath the base plate 146 such that it abuts the base 
plate 146 to limit upward travel of the sliding collar 170 and define an 
upper position of the sliding collar 170 on the needle 162. In the upper 
position, the lateral hole 168 is surrounded by the sealing portion 174 of 
the collar 170 to seal the lateral hole 168 and the blunt end 164 of the 
needle 162 is generally even with the upper surface 176 of the collar 170. 
In the illustrated configuration, the needle 162 is an eighteen gauge 
stainless steel needle with an inside diameter of about 1.04 millimeters, 
an outside diameter of about 1.2 millimeters, and a length of about 30 
millimeters. The lateral hole 168 is generally rectangular with dimensions 
of about 0.55 millimeters by 0.70 millimeters and is located about 1.2 
millimeters from the upper end of the needle 162. The sealing portion 174 
of the sliding collar 170 is made of ethylene propylene dimer monomer and 
the generally rigid portion 176 is made of polypropylene or any other 
suitably rigid material. The sealing portion 174 is molded with an 
aperture to snugly receive the needle 162 and form a robust seal between 
the inner surface 178 and the needle 162. Alternative dimensions, 
materials or configurations might also be used. 
To install an ink supply 20 within the docking bay 38, a user can simply 
place the lower end of the ink supply 20 between the opposing walls 134 
and 136 with one edge in one vertical channel 138 and the other edge in 
the other vertical channel 140, as shown in FIGS. 8 and 9. The ink supply 
20 is then pushed downward into the installed position, shown in FIG. 10, 
in which the bottom of the cap 32 abuts the base plate 146. As the ink 
supply 20 is pushed downward, the fluid outlet 28 and fluid inlet 42 
automatically engage and open to form a path for fluid flow from the ink 
supply 20 to the printer, as explained in more detail below. In addition, 
the actuator 40 enters the aperture 34 in the cap 32 to pressurize the 
pump 26, as explained in more detail below. 
Once in position, the engagement prongs 144 on each side of the docking 
station engage the detentes 118 formed in the shell 30 to firmly hold the 
ink supply 20 in place. The leaf springs 142, which allow the engagement 
prongs 144 to move outward during insertion of the ink supply 20, bias the 
engagement prongs 144 inward to positively hold the ink supply 20 in the 
installed position. Throughout the installation process and in the 
installed position, the edges of the ink supply 20 are captured within the 
vertical channels 138 and 140 which provide lateral support and stability 
to the ink supply 20. In some embodiments, it may be desirable to form 
grooves in one or both of the channels 138 and 140 which receive the 
vertical rib 116 formed in the shell 30 to provide additional stability to 
the ink supply 20. 
To remove the ink supply 20, a user simply grasps the ink supply 20, using 
the contoured gripping surfaces 114, and pulls upward to overcome the 
force of the leaf springs 142. Upon removal, the fluid outlet 28 and fluid 
inlet 42 automatically disconnect and reseal leaving little, if any, 
residual ink and the pump 26 is depressurized to reduce the possibility of 
any leakage from the ink supply 20. 
Operation of the fluid interconnect, which comprises the fluid outlet 28 
and the fluid inlet 42, during insertion of the ink supply 20 is 
illustrated in FIGS. 9 and 10. FIG. 9 shows the fluid outlet 28 upon its 
initial contact with the fluid inlet 42. As illustrated in FIG. 9, the 
housing 150 has partially entered the cap 32 through aperture 36 and the 
lower end of the fluid outlet 28 has entered into the top of the housing 
150. At this point, the crimp cover 106 contacts the sealing collar 170 to 
form a seal between the fluid outlet 28 and the fluid inlet 42 while both 
are still in their sealed positions. This seal acts as a safety barrier in 
the event that any ink should leak through the septum 104 or from the 
needle 162 during the coupling and decoupling process. 
In the illustrated configuration, the bottom of the fluid inlet 42 and the 
top of the fluid outlet 28 are both generally planar. Thus, very little 
air is trapped within the seal between the fluid outlet 28 of the ink 
supply 20 and the fluid inlet 42 of the printer. This facilitates proper 
operation of the printer by reducing the possibility that air will enter 
the fluid outlet 28 or the fluid inlet 42 and reach the ink-jets in the 
print head. 
As the ink supply 20 is inserted further into the docking bay 38, the 
bottom of the fluid outlet 28 pushes the sliding collar 170 downward, as 
illustrated in FIG. 10. Simultaneously, the needle 162 enters the slit 110 
and passes through the septum 104 to depress the sealing ball 102. Thus, 
in the fully inserted position, ink can flow from the boss 99, around the 
sealing ball 102, into the lateral hole 168, down the bore 166, through 
the trailing tube 169 to the print head. 
Upon removal of the ink supply 20, the needle 162 is withdrawn and the 
spring 100 presses the sealing ball 102 firmly against the septum 104 to 
establish a robust seal. In addition, the slit 110 closes to establish a 
second seal, both of which serve to prevent ink from leaking through the 
fluid outlet 28. At the same time, the spring 172 pushes the sliding 
collar 170 back to its upper position in which the lateral hole 168 is 
encased within the sealing portion of the collar 170 to prevent the escape 
of ink from the fluid inlet 42. Finally, the seal between the crimp cover 
106 and the upper surface 176 of the sliding collar 170 is broken. With 
this fluid interconnect, little, if any, ink is exposed when the fluid 
outlet 28 is separated from the fluid inlet 42. This helps to keep both 
the user and the printer clean. 
Although the illustrated fluid outlet 28 and fluid inlet 42 provide a 
secure seal with little entrapped air upon sealing and little excess ink 
upon unsealing, other fluid interconnections might also be used to connect 
the ink supply 20 to the printer. 
When the ink supply 20 is inserted into the docking bay 38, the actuator 40 
enters through the aperture 34 in the cap 32 and into position to operate 
the pump 26. FIGS. 11A-D illustrate various stages of the pump's 
operation. FIG. 11A illustrates the fully charged position of the pump 26. 
The flexible diaphragm 66 is in its lowermost position, and the volume of 
the chamber 56 is at its maximum. The actuator 40 is pressed against the 
diaphragm 66 by the compression spring 156 to urge the chamber 56 to a 
reduced volume and create pressure within the pump chamber 56. With the 
pump chamber 56 pressurized, the valve 64 closes to prevent the flow of 
ink from the chamber 56 back into the reservoir 24, causing the ink to 
pass from the chamber 56 through the pump outlet 62 and the conduit 84 to 
the fluid outlet 28. In the illustrated configuration, the compression 
spring 156 is chosen so as to create a pressure of about 1.5 pounds per 
square inch within the chamber 56. Of course, the desired pressure may 
vary depending on the requirements of a particular printer and may vary 
through the pump stroke. For example, in the illustrated embodiment, the 
pressure within the chamber will vary from about 90-45 inches of water 
column during the pump stroke. 
As ink is depleted from the pump chamber 56, the compression spring 156 
continues to press the actuator 40 upward against the diaphragm 66 to 
maintain a pressure within the pump chamber 56. This causes the diaphragm 
66 to move upward to an intermediate position decreasing the volume of the 
chamber 56, as illustrated in FIG. 11B. 
As still more ink is depleted from the pump chamber 56, the diaphragm 66 is 
pressed to its uppermost position, illustrated in FIG. 11C. In the 
uppermost position, the volume of the chamber 56 is at its minimum 
operational volume. 
As illustrated in FIG. 11D, during the refresh cycle the cam 158 is rotated 
into contact with the lever 152 to compress the compression spring 156 and 
move the actuator 40 to its lowermost position. In this position, the 
actuator 40 does not contact the diaphragm 66. 
With the actuator 40 no longer pressing against the diaphragm 66, the pump 
spring 70 biases the pressure plate 68 and diaphragm 66 outward, expanding 
the volume and decreasing the pressure within the chamber 56. With 
decreased pressure within the chamber 56, the valve 64 is open and ink is 
drawn from the reservoir 24 into the chamber 56 to refresh the pump 26, as 
illustrated in FIG. 11D. The check valve at the print head, the flow 
resistance within the trailing tube, or both, will limit ink from 
returning to the chamber 56 through the conduit 84. Alternatively, a check 
valve may be provided at the outlet port, or at some other location, to 
prevent the return of ink through the outlet port and into the chamber 56. 
After a predetermined amount of time has elapsed, the refresh cycle is 
concluded by rotating the cam 158 back into its disengaged position and 
the ink supply 20 typically returns to the configuration illustrated in 
FIG. 11A. 
The configuration of the ink supply 20 is particularly advantageous because 
only the relatively small amount of ink within the chamber 56 is 
pressurized when the actuator is engaged with the diaphragm 66. The large 
majority of the ink is maintained within the reservoir 24 at approximately 
ambient pressure. Thus, it is less likely to leak and, in the event of a 
leak, can be more easily contained. 
The illustrated diaphragm pump has proven to be very reliable and well 
suited for use in the ink supply 20. However, other types of pumps may 
also be used. For example, a piston pump, a bellows pump, or other types 
of pumps might be adapted for use with the present invention. 
In accordance with the method of the present invention, the ink supply 20 
having a valve 64, a chamber 56 and a fluid outlet 28, as just described, 
is refilled once depleted. 
The ink supply 20 is removed from the docking bay 38 for refilling. When 
the ink supply 20 is removed, the diaphragm 66 is no longer in contact 
with the actuator 40, which allows the chamber 56 to expand to its maximum 
volume and removes the chamber pressure applied by the actuator 40. With 
such pressure removed, the unattached sides of the valve 64 are free to 
bend downward, slightly opening the valve 64 (see FIG. 13). The bend in 
the valve 64 that occurs in the absence of pressure (other than the static 
ink pressure) in the chamber 56 is attributable to the slight deformation 
of the valve 64 that results as ink is normally pumped through the valve 
64 into the chamber 56, forcing the valve 64 into an open, bent 
configuration. In short, the valve 64, under static conditions (i.e., the 
actuator in the disengaged position), assumes a slightly open position. 
With the valve 64 so positioned, a gradual, low-pressure flow of refill 
ink may be directed through the valve 64 into the reservoir 24, as 
depicted in FIG. 13 and explained more fully below. 
The ink supply 20 to be refilled may be placed in a stabilizing base 202, 
as shown in FIG. 12, or held steady by hand. The pump is permitted to 
assume the fully charged position, so that chamber 56 is essentially 
unpressurized. As illustrated in FIG. 12, a refill needle 200 is inserted 
into the slit in the septum 104 of the fluid outlet 28. The refill needle 
200 is configured as the previously described needle 162 of the fluid 
inlet 42. Other configurations for a refill needle could be used. The 
needle 200 emanates from a source of refill ink that provides ink having 
the appropriate physical and chemical characteristics of the originally 
supplied ink. 
Insertion of the refill needle 200 depresses the sealing ball 102 and the 
spring 100, thereby opening a path for ink flow through the fluid outlet 
28, conduit 84, into the chamber 56. As previously stated, the valve 64 is 
slightly open and, thus, a complete path is available for flow of refill 
ink from the fluid outlet 28, through conduit 84, into chamber 56, through 
inlet 60, and into the reservoir 24 as shown by the arrows in FIG. 12. 
The rate at which the refill ink is supplied is selected to be sufficiently 
slow, so that the valve 64 remains open during the entire refill process. 
In this regard, the refill flow from an ink refill container (not shown) 
may be induced by gravity, with the refill container elevated by an amount 
sufficient to create a pressure head to refill the reservoir 24 without 
forcing the valve 64 closed. 
The method of the present invention is also useful for refilling an ink 
supply having a valve that is heat staked to the chassis 22 at a location 
other than the midpoints of its short sides. In particular, the present 
method could be used on a valve 64b that is heat staked to the chassis 22 
on only one side, as shown in FIG. 14. In this case, the valve 64b would 
be likely to remain in a slightly deformed, open state that creates a 
relatively larger gap to allow refill ink flow into the reservoir 24. 
Additionally, the method of the present invention could be used for 
refilling an ink supply having a unitary spring/pressure plate 92 as shown 
in FIG. 7 and described previously. 
This detailed description is set forth only for purposes of illustrating 
examples of the present invention and should not be considered to limit 
the scope thereof in any way. Clearly, numerous additions, substitutions, 
and other modifications can be made to the invention without departing 
from the scope of the invention which is defined in the appended claims 
and equivalents thereof.