Abstract:
An ink containment and dispensing device for an ink-jet printer is provided with a main reservoir in the form of a flexible pouch, which is typically maintained at ambient pressure. The main reservoir is coupled to a variable volume chamber via a one-way valve which allows the flow of ink from the reservoir to the chamber and prevents 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 outward ink. However, when the ink supply is installed in a printer, the fluid outlet establishes a fluid connection between the chamber and the printer. The chamber is part of a pump provided with the ink supply that can be actuated to supply ink from the reservoir to the printer. The pump has a linearly acting pumping member and a flexible diaphragm that overlies the pumping member, the diaphragm being impervious to the transmission of oxygen and moisture therethrough to prevent degradation of the ink within the chamber.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is directed to improvements in the invention disclosed in U.S. patent application Ser. No. 08/429,987, now U.S. Pat. No. 5,784,087 an application in which I am named as a joint inventor. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to a liquid containment device with a self-contained pump for dispensing liquid in small doses of a predetermined volume. More particularly, this invention relates to a replaceable containment device of the foregoing character which is useful in an ink-jet printer for containing a supply of printing ink and for dispensing the printing ink to a printing head upon the actuation of the self-contained pump. 
     BACKGROUND AND BRIEF DESCRIPTION OF THE INVENTION 
     A pending U.S. patent application filed by Bruce Cowger and Norman Pawlowski, Jr., for an invention entitled “Ink Supply For An Ink-Jet Printer,” describes an ink supply for an ink-jet printer that is separate from the printer ink pen, and can be replaced upon the emptying of the ink supply without the need to replace the printer ink pen. The ink supply of the aforesaid U.S. patent application incorporates a self-contained pumping device for dispensing ink from a pumping chamber, and describes, as an embodiment of such a pumping device, a bellows pump. However, a bellows pump requires a relatively large extended surface of a semi-rigid material, such as a polymeric material, and is subject to a relatively high rate of oxygen and moisture transfer through the material of the bellows. This oxygen and/or moisture transfer can result in the degradation of the ink within the ink supply, especially in a printer that is used only infrequently. Further, the bellows is subject to leakage at the location of its attachment to another portion of the ink supply. According to the aforesaid pending U.S. patent application Ser. No. 08/429,987, these and other problems associated with the use of a bellows can be avoided by the use of a pumping device having a rigid perimetrical wall, preferably formed integrally with the associated chassis structure of the ink supply, with a linearly acting pumping member that is moveable within a pumping chamber defined by the rigid wall to pressurize ink within the pumping chamber, and a flexible moisture and oxygen barrier film heat sealed to an edge of the perimetrical wall in a continuous pattern and overlying the pumping member. 
     An ink supply according to the aforesaid U.S. patent application Ser. No. 08/429,987 incorporates a check valve in the form of a thin, flexible flapper valve heat staked to the chassis to prevent the return of ink from the pumping chamber to the pouch upon the pressurization of the ink during a dispensing cycle. However, the heating of the flapper valve needed to heat stake the flapper valve to the chassis can result in permanent distortion of the flapper valve, with a resultant loss in effectiveness of its flow retarding qualities during ink dispensing cycles. It has now been found, however, in accordance with certain embodiments of the present invention that a suitable check valve in the form of a flapper valve can be provided without the need to heat stake the flapper valve to the chassis by providing a spring to urge the flapper valve against the chassis, either in the form of a spring that is aligned with the opening in the chassis that is to be closed by the flapper valve or a spring that is offset with respect to such opening. It has also been found, in accordance with an alternative embodiment of the present invention, that a suitable check valve can be provided in the form of a spring biased or free-floating check ball that selectively seats against a fixed seat to block the return of ink from the pumping chamber to the pouch during a pumping cycle while permitting ink flow from the pouch into the pumping chamber at the conclusion of a pumping cycle. 
     Accordingly, it is an object of the present invention to provide an improved liquid containing and dispensing device. It is also a corollary object of the present invention to provide an improved device of the foregoing character that is useful in containing and dispensing ink in an ink-jet printer. 
     More particularly, it is an object of the present invention to provide a liquid containment and dispensing device with an improved check valve to prevent the return of liquid from a pumping element of the device to a liquid containing pouch during a pumping cycle and it is a corollary object of the present invention to provide a device of the foregoing character that is useful in containing and dispensing ink in an ink-jet printer. 
     For a further understanding of the present invention and the objects thereof, attention is directed to the drawing and the following brief description thereof, to the detailed description of the preferred embodiment of the invention, and to the appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 is a side view of a liquid containment and dispensing device according to an embodiment of the present invention; 
     FIG. 2 is a an exploded view of the device of FIG. 1; 
     FIG. 3 is a plan view of the device of FIGS. 1 and 2 taken on line  3 — 3  of FIG. 1; 
     FIG. 4 is a plan view of a component of the device of FIGS. 1-3 taken on line  4 — 4  of FIG. 5; 
     FIG. 5 is a side view of the component of FIG. 4; 
     FIG. 6 is a plan view of the component of FIGS. 4 and 5 taken on line  6 — 6  of FIG. 5; 
     FIG. 7 is a fragmentary sectional view taken on line  7 — 7  of FIG.  3  and at an enlarged scale; 
     FIG. 8 is a fragmentary exploded view of a portion of the device of FIGS. 1-7; 
     FIG. 9 is a fragmentary view similar to FIG. 8 showing the elements of FIG. 8 in assembled relationship to one another; 
     FIG. 10 is a fragmentary plan view of an alternative embodiment of a portion of the liquid containment and dispensing device of FIGS. 1-9; 
     FIG. 11 is a fragmentary sectional view taken on line  11 — 11  of FIG. 10; 
     FIG. 12 is a fragmentary elevational view, partly in section, of another alternative embodiment of a portion of the liquid containment and dispensing device of FIGS. 1-9; and 
     FIGS. 13-18 are views similar to FIG. 12 of additional alternative embodiments of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     An ink containment and dispensing device in accordance with the embodiment of the invention described in the aforesaid U.S. patent application Ser. No. 08/429,987 is identified in FIG. 1 by reference numeral  10 . The device  10  has a hard protective shell  12  which contains a flexible pouch  14  for containing ink. The shell  12  is attached to a chassis  16 , which houses a pump  18  and a fluid outlet  20 . A protective cap  22  is attached to the chassis  16  and a label  24  is glued to the outside of the shell  12  and cap  22  elements of the device  10  to secure the shell  12 , chassis  16 , and cap  22  firmly together. The cap  22  is provided with apertures which allow access to the pump and the fluid outlet. 
     The device  10  is adapted to be removably inserted into a docking bay (not shown) within an ink-jet printer. When the device  10  is inserted into the printer, a fluid inlet in the docking bay is adapted to engage the fluid outlet  20  to allow ink flow from the device  10  to the printer. An actuator (not shown) in the docking bay is adapted to engage the pump  18 . Operation of the actuator causes the pump  18  to provide ink in a series of small doses of a predetermined volume from the flexible pouch  14 , through the fluid outlet  20 , to the fluid inlet of the docking bay and then to the printer. 
     The chassis  16  is provided with a fill port  32  at one end and an exhaust port  34  at the other end. Ink can be added to the ink supply through the fill port  32  while air displaced by the added ink is exhausted through the exhaust port  34 . After the ink supply is filled, the fill port  32  is sealed with a ball  35  press fit into the fill port  32 . 
     A pumping chamber  36  having an open bottom is formed on the bottom of the chassis  16  within a rigid perimetrical wall  37 , which is preferably formed integrally with the chassis  16 . As described in more detail below, the chamber  36  can be pressured to supply ink to the printer without pressurizing the interior of the pouch  14 . The top of the chamber  36  is provided with an inlet port  38  through which ink may enter the chamber  36  from the pouch  14  by gravity and/or by a negative pressure within the chamber  36 . An outlet port  40  through which ink may be expelled from the chamber  36  is also provided. 
     A one-way flapper valve  42  located at the bottom of the inlet port  38  serves to limit the return of ink from the chamber  36  to the pouch  14 . The flapper valve  42  is a rectangular piece of flexible material. In the illustrated embodiment the valve  42  is positioned over the bottom of the inlet port  38  and is heat staked to the chassis  16  at the midpoints of its short sides. When the pressure within the chamber  36  drops below that in the pouch  14 , the unstaked sides of the valve  42  each flex to allow the flow of ink through the inlet port  38  and into the chamber  36 . By heat staking the valve  42  to the chassis  16  along an opposed pair of sides, less flexing of the valve  42  is required or permitted than would be the case if the valve  42  were staked only along a single side, thereby ensuring that it closes more securely, and this effect is enhanced by doing the heat staking at the midpoints of the shorter sides, as opposed to the longer sides. 
     In the illustrated embodiment the flapper valve  42  is made of a two ply material. The outer ply is a layer of low density polyethylene 0.0015 inches thick. The inner ply is a layer of polyethylene terephthalate (PET) 0.0005 inches thick. The illustrated flapper valve  42  is approximately 5.5 millimeters wide and 8.7 millimeters long. Such a material is impervious to the flow of ink therethrough when the valve  42  is in its closed position. 
     The bottom of the chamber  36  is covered with a flexible diaphragm  44 . The diaphragm  44  is slightly larger than the opening at the bottom of the chamber and is sealed around the free edge of the perimetrical wall  37  that defines the chamber  36 . The excess material in the oversized diaphragm  44  allows the diaphragm to flex up and down to vary the volume of the chamber  36 . In the illustrated device, the displacement of the diaphragm  44  allows the volume of the chamber  36  to be varied by about 0.7 cubic centimeters. The fully expanded volume of the illustrated chamber  36  is between about 2.2 and 2.5 cubic centimeters. 
     In the illustrated embodiment, the diaphragm  44  is made of a multi-ply material having a layer of low density polyethylene 0.0005 inches thick, a layer of adhesive, a layer of metallized polyethylene terephthalate (PET) 0.00048 inches thick, a layer of adhesive, and a layer of low density polyethylene 0.0005 inches thick. Of course, other suitable materials may also be used to form the diaphragm  44 . The diaphragm  44  in the illustrated embodiment is heat staked, using conventional methods, to the free edge of the wall  37  of the chamber  36 . During the heat staking process, the low density polyethylene in the diaphragm will seal any folds or wrinkles in the diaphragm  44 . The diaphragm  44 , thus, is impervious to the transmission of oxygen and moisture therethrough, thereby safeguarding the ink in the chamber  36  from degradation by exposure to any such substance. 
     Within the chamber  36  a pressure plate  46  is positioned adjacent the diaphragm  44 , the pressure plate  46  serving as a piston with respect to the chamber  36 . A pump spring  48 , made of stainless steel in the illustrated embodiment, biases the pressure plate  46  against the diaphragm  44  to urge the diaphragm outward so as to expand the size of the chamber  36 . One end of the pump spring  48  is received on a spike  50  formed on the top of the chamber  36  and the other end of the pump spring  48  is received on a spike  52  formed on the pressure plate  46  in order to retain the pump spring  48  in position. The pressure plate  46  in the illustrated embodiment is molded of high density polyethylene. 
     A hollow cylindrical boss  54  extends downward from the chassis  16  to form the housing of the fluid outlet  20 , the boss  54  being formed integrally with the chassis  16 . A bore  56  of the hollow boss  54  has a narrow throat  54   a  at its lower end. A sealing ball  58 , made of stainless steel in the illustrated embodiment, is positioned within the bore  56 . The sealing ball  58  is sized such that it can move freely within the bore  56 , but cannot pass through the narrow throat portion  54   a  thereof. A sealing spring  60  is positioned within the bore  56  to urge the sealing ball  58  against the narrow throat  54   a  to form a seal and prevent the flow of ink through the fluid outlet. A retaining ball  62 , made of stainless steel in the illustrated embodiment, is press fit into the top of the bore to retain the sealing spring  60  in place. The bore  56  is configured to allow the free flow of ink past the retaining ball  62  and into the bore  56 . 
     A raised manifold  64  is formed on the top of the chassis  16 . The manifold  64  forms a cylindrical boss around the top of the fill port  32  and a similar boss around the top of the inlet port  38  so that each of these ports is isolated. The manifold  64  extends around the base of the fluid outlet  20  and the outlet port  40  to form an open-topped conduit  66  joining the two outlets. 
     The flexible ink pouch  14  is attached to the top of the manifold  64  so as to form a top cover for the conduit  66 . In the illustrated embodiment, this is accomplished by heat staking a rectangular plastic sheet  68  to the top surface of the manifold  64  to enclose the conduit  66 . In the illustrated embodiment, the chassis  16  molded of high density polyethylene and the plastic sheet is low density polyethylene that is 0.002 inches thick. These two materials can be easily heat staked to one another using conventional methods and are also readily recyclable. 
     After the plastic sheet  68  is attached to the chassis  16 , the sheet is folded and sealed around its two sides and top to form the flexible ink pouch  14 . Again, in the illustrated embodiment, heat staking can be used to seal the perimeter of the flexible pouch  14 . The plastic sheet over the fill port  32  and over the inlet port  38  can be punctured, pierced, or otherwise removed so as not to block the flow of ink through these ports. 
     Although the flexible pouch  14  provides an ideal way to contain ink, it may be easily punctured or ruptured and allows a relatively high amount of water loss from the ink. Accordingly, to protect the pouch  14  and to limit water loss, the pouch  14  is enclosed within a protective shell  12 . In the illustrated embodiment, the shell  12  is made of clarified polypropylene, which is sufficiently translucent to permit inspection of the ink within the pouch  14  to determine that an adequate volume of ink remains for proper operation of the printer. 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 may vary in other embodiments. 
     The top of the shell  12  has a number of raised ribs  70  to facilitate gripping of the shell  12  as it is inserted in or withdrawn from the docking bay. A vertical rib  72  projects laterally from each side of the shell  12 . The vertical rib  72  can be received within a slot (not shown) in the docking bay to provide lateral support and stability to the ink supply when it is positioned within the printer. The bottom of the shell  12  is provided with two circumferential grooves or recesses  76  which engage two circumferential ribs or beads  78  formed on a depending perimetrical wall  79  of the chassis  16  to attach the shell  12  to the chassis  16  in a snap fit. 
     The attachment between the shell  12  and the chassis  16  should, preferably, be snug enough to prevent accidental separation of the chassis from the shell and to resist the flow of ink from the shell should the flexible reservoir develop a leak. However, it is also desirable that the attachment not form a hermetic seal to allow the slow ingress of air into the shell as ink is depleted from the reservoir  14  to maintain the pressure inside the shell generally the same as the ambient pressure. Otherwise, a negative pressure may develop inside the shell and inhibit the flow of ink from the reservoir. The ingress of air should be limited, however, in order to maintain a high humidity within the shell and minimize water loss from the ink. 
     In the illustrated embodiment, the shell  12  and the flexible pouch  14  which it contains have the capacity to hold approximately thirty cubic centimeters of ink. The shell is approximately 67 millimeters wide, 15 millimeters thick, and 60 millimeters high. The flexible pouch  14  is sized so as to fill the shell without undue excess material. Of course, other dimensions and shapes can also be used depending on the particular needs of a given printer. 
     To fill the device  10 , ink can be injected through the fill port  32 . As it is filled, the flexible pouch  14  expands so as to substantially fill the shell  12 . As ink is being introduced into the pouch, the sealing ball  58  can be depressed to open the fluid outlet and a partial vacuum can be applied to the fluid outlet  20 . The partial vacuum at the fluid outlet causes ink from the pouch  14  to fill the chamber  36 , the conduit  66 , and the bore  56  of the cylindrical boss  54  such that little, if any, air remains in contact with the ink. The partial vacuum applied to the fluid outlet  20  also speeds the filling process. To further facilitate the rapid filling of the pouch  14 , an exhaust port  34  is provided to allow the escape of air from the shell as the reservoir expands. Once the ink supply is filled, a ball  35  is press fit into the fill port  32  to prevent the escape of ink or the entry of air. 
     Of course, there are a variety of other ways which can also be used to fill the present ink containment and dispensing device. In some instances, it may be desirable to flush the entire device with carbon dioxide prior to filling it with ink. In this way, any gas trapped within the device 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 device as possible so that bubbles and the like do not enter the print head or the trailing tube. 
     The protective cap  22  is placed on the device  10  after the reservoir is filled. The protective cap is provided with a groove  80  which receives a rib  82  on the chassis to attach the cap to the chassis. The cap carries a lug  84  which plugs the exhaust port  34  to limit the flow of air into the chassis and reduce water loss from the ink. A stud  86  extends from each end of the chassis  16  and is received within an aperture in the cap  22  to aid in aligning the cap and to strengthen the union between the cap and the chassis. The free ends of the studs  86 , which extend beyond the apertures of the cap  22 , are preferably deformed after the cap  22  is in place, for example, by contacting them with a heated tool, to provide a tamper resistant attachment of the cap  22  to the chassis  16 . Further, the label  24  is glued to the sides of the device  10  to hold the shell  12 , chassis  16 , and cap  22  firmly together. In the illustrated embodiment, a hot-melt pressure sensitive or other adhesive is used to adhere the label in a manner that prevents the label from being peeled off and inhibits tampering with the ink supply. 
     The cap  22  in the illustrated embodiment is provided with a vertical rib  90  protruding from each side. The rib  90  is an extension of the vertical rib  72  on the shell and is received within the slot provided in the docking bay in a manner similar to the vertical rib  72 . In addition to the rib  90 , the cap  22  has protruding keys  92  located on each side of the rib  90 . One or more of the keys  92  can be optionally deleted or altered so as to provide a unique identification of the particular ink supply by color or type. Mating keys (not shown), identifying a particular type or color of ink supply can be formed in the docking bay. In this manner, a user cannot inadvertently insert an ink supply of the wrong type or color into a docking bay. This arrangement is particularly advantageous for a multi-color printer where there are adjacent docking bays for ink supplies of various colors. 
     In the embodiment of FIGS. 10-11, elements that correspond to the elements of the embodiment of FIGS. 1-9 are identified by a  100  series numeral, the last two digits of which correspond to the two digits of the corresponding element of the embodiment of FIGS. 1-9. 
     The flapper valve of the embodiment of FIGS. 10-11 is identified by reference numeral  142 . The flapper valve  142 , which is formed of a thin flexible sheet or lamination, serves to permit the flow of ink through an inlet port  138  in a molded plastic chassis  116  into a pumping chamber  136  that is defined by the perimetrical wall  137 . The flow of ink through the inlet port  138  into the pumping chamber  136  occurs when the pressure in the pumping chamber  136  is less than the pressure in the inlet port  138 . In that regard, the flapper valve  142  is not heat staked to the adjacent structure of a chassis  116 , it being resiliently biased thereagainst by a pump spring  148 . The opposed end of the pump spring  148 , not shown, engages a pressure plate, also not shown, that corresponds in construction and function to the pressure plate  46  of the embodiment of FIGS. 1-9. In any case, when the pressure in the pumping chamber  136  is less than the pressure in the inlet port  138 , the flapper valve  142  will unseat from the adjacent structure of the chassis  116 , which will permit ink to flow through the inlet port  138  into the pumping chamber  136 , by gravity and/or by pressure. When the pressure in the pumping chamber  136  is greater than the pressure in the inlet port  138 , however, which will be the case during a pumping cycle of an ink-jet containment and dispensing device that incorporates the flapper valve  142 , the pump spring  148  will expand to securely bias the flapper valve  142  against the opening of the inlet port  138  into the pumping chamber  136 , thereby blocking the reverse flow of ink from the pumping chamber  136  into the inlet port  138 . As is clear from FIGS. 10-11 of the drawing, the pump spring  148  is axially aligned with the inlet port  138 . 
     In the embodiment of FIG. 12, elements that correspond to the elements of the embodiment of FIGS. 1-9 are identified by a  200  series numeral, the last two digits of which correspond to the corresponding element of the embodiment of FIGS. 1-9. 
     The flapper valve of the embodiment of FIG. 12 is identified by reference numeral  242 . The flapper valve  242 , which is formed of a thin flexible sheet or lamination, serves to permit the flow of ink through an inlet port  238  in a molded plastic chassis  216  into a pumping chamber  236  that is defined by a perimetrical wall, not shown, which corresponds to the perimetrical wall  37  of the embodiment of FIGS. 1-9, when the pressure in the pumping chamber  236  is less than the pressure in the inlet port  238 . In that regard, the flapper valve  242  is not heat staked to the adjacent structure of a chassis  216 , it being resiliently biased thereagainst by a pump spring  248 . The opposed end of the pump spring  248 , not shown, engages a pressure plate, also not shown, that corresponds in construction and function to the pressure plate  46  of the embodiment of FIGS. 1-9. In any case, when the pressure in the pumping chamber  236  is less than the pressure in the inlet port  238 , the flapper valve  242  will be biased upwardly to unseat from the adjacent structure of the chassis  216 , which will permit ink to flow through the inlet port  238  into the pumping chamber  236 , by gravity and/or by pressure. When the pressure in the pumping chamber  236  is greater than the pressure in the inlet port  238 , however, which will be the case during a pumping cycle of an ink-jet containment and dispensing device that incorporates the flapper valve  242 , the flapper  242  will be biased downwardly to seat against the opening of the inlet port  238  into the pumping chamber  236 , thereby blocking the reverse flow of ink from the pumping chamber  236  into the inlet port  238 . As is clear from FIG. 12 of the drawing, the pump spring  248  is axially offset with respect to the inlet port  238 . Thus, the flapper valve  242  preferably should have some inherent spring-like qualities, and the seating of the flapper valve  242  against the opening from the inlet port  238  into the pumping chamber  236  is preferably augmented by requiring that the free end of the flapper valve  242 , that is, the end that seats against the opening from the inlet port  238  into the pumping chamber  236 , be flexed upwardly, as shown in FIG.  12 . 
     In the embodiment of FIG. 13, elements that correspond to the elements of the embodiment of FIGS. 1-9 are identified by a  300  series numeral, the last two digits of which correspond to the last two digits of the corresponding element of the embodiment of FIGS. 1-9. 
     A molded plastic chassis  316  incorporates an inlet port  338  to permit ink to flow into a pumping chamber  336 , which is circumscribed by a perimetrical wall, not shown, that corresponds to the perimetrical wall  37  of the embodiment of FIGS. 1-9. The chassis  316  incorporates an annular, frustoconical seat  316   a  within the inlet port  338 , and one-way flow of ink through the inlet port  338  into the pumping chamber  336  is provided by a floating check ball  342 , that seats against the seat  316   a  in the flow blocking position of the ball  342 . The ball  342  is normally urged against the seat  316   a  by a sealing spring  342   a , an end of which bears against the ball  342  and an opposed end of which is retained by an end of a pump spring  348 . In that regard, the illustrated end of the pump spring  348  is received on a spike  350 , which is formed integrally with the chassis  316 , the opposed end of the pump spring  348 , not shown, engaging a pressure plate, also not shown, that corresponds in construction and function to the pressure plate  46  of the embodiment of FIGS. 1-9. 
     In the embodiment of FIG. 14, elements that correspond to the elements of the embodiment of FIGS. 1-9 are identified by a  400  series numeral, the last two digits of which correspond to the last two digits of the corresponding element of the embodiment of FIGS. 1-9. 
     An ink-jet containment and dispensing device according to the embodiment of FIG. 14 has a molded plastic chassis  416  with an inlet port  438  therein, the chassis  416  having an annular, frustoconical seat  416   a  in the inlet port  438 . Flow of ink through the inlet port  438  into a pumping chamber  436 , which is circumscribed by a perimetrical wall, not shown, that corresponds to the perimetrical wall  37  of the embodiment of FIGS. 1-9, is selectively permitted or prevented by a free-floating check ball  442  positioned within the inlet port  438  and adapted to block flow through the inlet port  438  when the ball  442  engages the seat  416   a . The ball  442  is free to travel within the inlet port  438 , within limits, which are defined by the seat  416   a  and a pump spring  448 , the illustrated end of which limits the travel of the ball  442  away from the seat  416   a . The pump spring  448 , which is securely positioned with respect to the ball  442  by a spike  450 , which is formed integrally with the chassis  416 , has an opposed end, not shown, which engages a pressure plate, also not shown, that corresponds in construction and function to the pressure plate  46  of the embodiment of FIGS. 1-9. The ball  442 , thus, is not positively mechanically urged against the seat  416   a , as in the manner of the ball  342  of the embodiment of FIG. 13, which is positively mechanically urged against the seat  316   a  by the spring  342   a . However, a higher pressure within the pumping chamber  436  and the pressure within the inlet port  438  will hydraulically urge the ball  442  against the seat  416   a , to thereby block the reverse flow of ink from the pumping chamber  436  back through the inlet port  438  during a pumping cycle of the embodiment of the invention illustrated in FIG.  14 . 
     In the embodiment of FIG. 15, elements that correspond to the elements of the embodiment of FIGS. 1-9 are identified by a  500  series numeral, the last two digits of which correspond to the last two digits of the corresponding element of the embodiment of FIGS. 1-9. 
     The embodiment of FIG. 15 is a variation of the embodiment of FIG. 14, and the variation lies in the configuration of a portion of the inlet port  538  that is downstream of an annular, frustoconical seat portion  516   a  in a molded plastic chassis  516 , such downstream portion being identified by reference numeral  538   a . The downstream portion  538   a  of the inlet port  538  is provided with a plurality of circumferentially spaced apart and longitudinally extending ribs  538   b  to guide the travel of the ball  542  as it lifts off the seat  516   a  under the influence of a higher pressure in an upstream portion of the inlet port  538  than in the downstream portion  538   a , which leads into a pumping chamber  536  that is defined by a perimetrical wall, not shown, that which corresponds to the perimetrical wall  37  of the embodiment of FIGS. 1-9. Because of the presence of the ribs  538   b , the cross-sectional area of the downstream portion  538   a  of the inlet port  538  is larger than the corresponding portion of the inlet port  438  of the embodiment of FIG. 14, thus increasing the rate of ink flow through the inlet port  538  for a small distance of liftoff of the ball  542  from the seat  516   a . Further, the ball  542  will seat against the seat  516   a  more quickly when the chamber  536  is pressurized because of the greater area of the downstream portion  538   a  of the inlet port  538 . In any case, the travel of the ball  542  within the inlet port  538  is limited by the presence of a pump spring  548 , which is similar to the pump spring  448  of the embodiment of FIG.  14  and is retained by a spike  550  that is formed integrally with the chassis  516 , in the manner that the pump spring  448  of the embodiment of FIG. 14 is held in place by the spike  450 . 
     In the embodiment of FIG. 16, elements that correspond to the elements of the embodiment of FIGS. 1-9 are identified by a  600  series numeral, the last two digits of which correspond to the last two digits of the corresponding element of the embodiment of FIGS. 1-9. 
     The embodiment of FIG. 16 may be considered to be a variation of the embodiment of FIGS. 10 and 11. In that regard, in the embodiment of FIG. 16, a molded plastic chassis  616  has an inlet port  638  for permitting ink to flow therethrough into a pumping chamber  636 , which is defined by a perimetrical wall, not shown, that corresponds to the perimetrical wall  37  of the embodiment shown in FIGS. 1-9. One-way flow of ink through the inlet port  638  into the pumping chamber  636  is ensured by a flat valve  642 , which seats against an annular seat  616   a  of the chassis  616  when pressure in the pumping chamber  636  is higher than pressure in the inlet port  638 , for example, during a pumping cycle of the ink containment and dispensing device that incorporates chassis  616 . While a pump spring  648  is provided in alignment with the inlet port  638 , the chassis  616  is provided with ribs  616   b  that limit the contact between the pump spring  648  and the flat valve  642  to contact after the flat valve  642  has lifted from the seat  616   a  by a predetermined distance. The axial extent of the ribs  616   b  can be varied to provide for an adjustable float of the flat valve  642 , as required to optimize its response time to changes in the pressure difference between the pressure in the inlet port  638  and the pressure in the pumping chamber  636 . 
     In the embodiment of FIG. 17, elements that correspond to the elements of the embodiment of FIGS. 1-9 are identified by a  700  series numeral, the last two digits of which correspond to the last two digits of the corresponding element of the embodiment of FIGS. 1-9. 
     In the embodiment of FIG. 17, one-way flow of ink through an inlet  738  of a molded plastic chassis  716  into a pumping chamber  736 , which is defined by a perimetrical wall, not shown, that corresponds to the perimetrical wall  37  of the embodiment of FIGS. 1-9, is ensured by a molded plastic, flexible member  742 . The member  742  has an annular, frustoconical surface  742   a  that engages an annular, frustoconical seat  716   a  of the chassis  716  when pressure in the pumping chamber  736  is higher than pressure in the inlet port  738 , for example, during a pumping cycle of the ink containment and dispensing device that incorporates chassis  716 . However, when pressure in the inlet port  738  is greater than pressure in the pumping chamber  736 , the member  742  can flex into the pumping chamber  736 , to lift its surface  742   a  from the surface  716   a  and thereby permit ink to flow into the pumping chamber  736 . The member  742  is positively positioned with respect to the chassis  716  by inserting it over a spike  750 , which is formed integrally with the chassis  716 , and by resiliently biasing the member  742  against the chassis  716  by a pump spring  748 , which is also retained on the spike  750 . The member  742  has an undercut portion  742   b , which serves as a hinge for the flexing of the member  742  into and out of the pumping chamber  736 , and the thickness and width of the undercut portion  742   b  can be adjusted to optimize the spring rate at which the member  742  seats and unseats due to changes in the pressure difference between the pumping chamber  736  and the inlet port  738 . 
     In the embodiment of FIG. 18, elements that correspond to the elements of the embodiment of FIGS. 1-9 are identified by an  800  series numeral, the last two digits of which correspond to the last two digits of the corresponding element of the embodiment of FIGS. 1-9. 
     In the embodiment of FIG. 18, a ball  842  is positioned within an inlet port  838  of a molded plastic chassis  816  to limit the flow of ink through the inlet port  838  to flow into a pumping chamber  836 , which is defined by a perimetrical wall, not shown, that corresponds to the perimetrical wall  37  of the embodiment of FIGS. 1-9. The chassis  816  has an annular, frustoconical surface  816 a against which the ball  842  seats when the pressure in the chamber  836  is higher than the pressure in the inlet port  838  to prevent flow from the pumping chamber  836  back through the inlet port  838 . When the pressure in the inlet port  838  is higher than the pressure in the pumping chamber  836 , the ball  842  will unseat from the surface  816   a , to permit the flow of ink from the inlet port  838  into the pumping chamber  836 . 
     The movement of the ball  842  within the inlet port  838  is limited by a circumferentially spaced-apart series of inwardly projecting tabs  816   b  of the chassis  816 , the ball  842  being insertable into the inlet port  838  by a pressed fit. The tabs  816   b  of the chassis  816  are formed in an upstanding, annular, frustoconical portion  816   c  of the chassis  816 . Because of the frustoconical configuration of the portion  816   c  of the chassis  816 , the outer surface of the portion  816   c  has a taper that facilitates the stripping of the chassis  816  from the mold and core used in the molding of the chassis  816 . 
     The liquid containment and dispensing device of the various embodiments of the present invention has been specifically described as a device for containing and dispensing a supply of printing ink in an ink-jet printer as the preferred embodiment of the invention. However, it is also contemplated that the present invention can easily be adapted to the containment and dispensing of other Newtonian (low viscosity) liquids. 
     Although the best mode contemplated by the inventor for carrying 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 be made without departing from the scope of the invention, such scope being limited solely by the terms of the following claims and the legal equivalents thereof.