Abstract:
An apparatus precisely delivers a prescribed amount of fluid into a degassed pouch contained in a cartridge. The apparatus has a rotating cartridge holding member that alternately positions the cartridge in either a horizontal position for filling or a vertical position for degassing. A digital weighing element associated with the fixture enables the cartridge to be weighed during the filling process to ensure the delivery of a predetermined amount of fluid.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is related to U.S. application Ser. No. 10/321,244, filed Dec. 17, 2002, by Edward B. Richter, et al., and titled, “Method Of Accurately Filling And Degassing A Pouch.” 
    
    
     FIELD OF THE INVENTION 
     The invention relates generally to the field of fluid filling. More particularly, the invention concerns an apparatus and method for filling a pouch with a fluid material in a manner that the pouch is degassed and receives a precise amount of the fluid material during the filling process. 
     BACKGROUND OF THE INVENTION 
     Commercial cartridges containing a pouch for receiving a fluid material, such as large ink jet cartridges (1000 ml or greater), are required for commercial, wide format ink jet printers. Typically, these cartridges consist of two-molded plastic cartridge halves generally ultrasonically sealed together. The cartridge also contains a pouch to be filled arranged in the interior portion of the cartridge. An opening is generally provided in a portion of the cartridge to provide access to the pouch as well as to means of inserting and removing the pouch from the cartridge. Further, a septum for filling the pouch is typically arranged in the top portion of the pouch. This septum is similar to devices used on pharmaceutical vials. Filling the pouch with a fluid material, such as ink, is generally undertaken after the cartridge has been assembled, by inserting a needle through the septum and pumping ink through the needle. Heretofore, it has generally been problematic to deliver a precise weight of fluid material into the pouch. 
     Another problem with current fluid filling developments is that the pouch or container being filled generally will contain a fair amount of residual gasses that negatively influence the outcome of the filling process. Those skilled in the art will appreciate that some printers, like ink jet printers having an electric print head rather than a thermal print head such as found in most desktop ink jet printers, require a more precise pouch loading precondition. Because of this, all gases must be evacuated from the pouch to be filled. An acceptable level of oxygen remaining in the cartridge is less than 1 part per million. 
     Therefore, there persists a need in the art for an apparatus and method for accurately and precisely filling and degassing a sealed pouch contained in a cartridge that is cost effective to manufacture, simple to use, and is reliable. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to overcoming one or more of the problems set forth above. Briefly summarized, according to one aspect of the present invention, an apparatus for precisely loading a pouch contained in a cartridge with fluid includes a holding member pivotably mounted to a rigid frame for holding the cartridge. A fluid injection member arranged in a central portion of the holding member for penetrating a fluid inlet end of the pouch to be filled. Means, structurally associated with the holding member, is provided for determining the weight of the cartridge containing the pouch to be filled. Further, means is provided for pivoting the cartridge containing the pouch to be filled relative to the rigid frame between a substantially horizontal position to a substantially vertical position. 
     The present invention has numerous advantages over prior developments. In particular, the present invention provides for removal of all entrapped air from the pouch to be filled, preventing degradation of the ink. Further, the present invention provides very accurate filling of the pouch to be filled. Moreover, handling of the cartridge/pouch is minimized using the present invention. Once the cartridge/pouch is inserted into the fixture, the entire filling/degassing operation takes place automatically. This also minimizes the number of times the septum is pierced during the manufacturing process. Still further, the throughput of the filling/degassing operation of the present invention is maximized. Also, the design of the mechanism is such that multiple cartridge/pouches can be filled/degassed simultaneously. Finally, the process can be applied to any product where accurate filling of a pouch with a liquid and removal of the air is required. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects, features, and advantages of the present invention will become more apparent when taken in conjunction with the following description and drawings, wherein identical reference numerals have been used, where possible, to designate identical features that are common to the figures, and wherein: 
     FIG. 1 is an elevated side view of the filling and weighing station of the invention; 
     FIG. 2 is an enlarged elevated side view of the filling and weighing mechanism of the invention; 
     FIG. 3 is a partially exploded perspective view of a cartridge used in the invention; and, 
     FIG. 4 is a schematic of the overall ink/air evacuation system of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Turning now to the drawings, and in particular to FIGS. 1 and 2, an apparatus  100  used with the method of the invention for filling a pouch is illustrated. According to FIGS. 1 and 2, apparatus  100  for loading a pouch  8  (FIG.  3 ), to be filled with a fluid, contained in a cartridge  10 , has a holding member  18  pivotably mounted at pivot point  30  to a rigid frame  6  for holding the cartridge  10 . Holding member  18  includes a plurality of spaced alignment members  24   a ,  24   b  that constrain cartridge  10  in a fixed orientation. Preferably, there are at least three spaced alignment members for precise constraint, although only two can be seen in the Figures. As shown in FIG. 2, fluid injection member, or needle  20 , is arranged preferably in a central portion of the support member  22 . According to FIG. 3, for fluid loading, needle  20  is urged into the septum, or fluid inlet end  26 , of the pouch  8 . 
     Accurate weighing of the pouch  8  is achieved using an electronic weighing element, preferably a load cell  12 , although a suitable analog weighing element can be used. In our invention (see FIGS.  1  and  2 ), load cell  12  is structurally associated with a slide assembly  16  connected to the frame  6  through fixture pivot point  30  for determining the weight of the cartridge  10 . Fixture pivot  30  provides the preferred means for pivoting the cartridge  10  relative to the frame  6  between a substantially horizontal position to a substantially vertical position. 
     As indicated above, the printer (not shown) that uses the cartridge  10  of the invention employs piezo electric print heads rather than the thermal print heads found in most desktop ink jet printers. Because of the characteristics of the piezo electric print head, all air must be evacuated from the pouch to be filled. An acceptable level of oxygen remaining in the cartridge is less than 1 part per million. To accomplish this, the process detailed below has been developed. 
     It is important to the invention that the filling process is undertaken when the cartridge  10  is in a substantially horizontal position. Skilled artisans will appreciate that a horizontal filling position minimizes foaming of the fluid, for instance ink, during the pumping operation. The cartridge  10 , containing pouch  8 , is first mounted into a fixture  28  supported by frame  6 . Cartridge  10  engages spaced alignment members  24   a ,  24   b  structurally associated with fixture  28 . This engagement of cartridge  10  with spaced alignment members  24   a ,  24   b  enables the septum  26  of pouch  8  contained in the cartridge  10  to align with fluid injection member or needle  20 . The needle  20  is, in turn, connected to a pumping system  46  having ink shut off valve  42  that pumps a fluid from reservoir  34  into the pouch  8 . 
     Referring to FIGS. 3 and 4, the pouch  8  contained in cartridge  10  in the substantially horizontal position is initially overfilled with the fluid by approximately 50 ml. The volume of fluid or ink, pumped into the pouch  8  to be filled is controlled by a pump  54 , supplied by reservoir  34 . 
     Referring to FIGS. 1 and 4, the fixture  28  that supports the cartridge  10  is then rotated through a pivot point  30  from a substantially horizontal position  48  to a substantially vertical position  50 . Rotation of cartridge  10  can be accomplished by any means including manually or automatically by means of a drive motor. This rotation of cartridge  10  causes the entrapped residual gases, e.g. air, to rise to the top of the pouch  8  to be filled. At the terminus point  52  of the rotation, a fixed bump stop  32  in the path of rotation provides an elastic impact force to the cartridge  10 . Bump stop  32 , positioned at the end of the vertical rotation of fixture  28 , facilitates the rise of air bubbles to the top of the pouch  8  to be filled. 
     Referring to FIG. 4, the preferred method of the invention for filling a pouch  8  with a fluid material, such as ink or a dye, includes the step of first evacuating the pouch  8  prior to associating the cartridge  10  with the ink toggle return valve  40 . Ink/air is removed from the pouch  8  to be filled by a vacuum pump  44 . The ink is separated from the air by a liquid trap  36  and returned to the reservoir  34 . 
     According to FIG. 4, to obtain a very accurately filled cartridge (+/−1 ml), preferably a load cell  12  is incorporated into the mechanism that supports the cartridge  10 . Load cell  12  continuously monitors the weight of the cartridge  10 , ink and gripper mechanism  14  (shown in FIGS.  1  and  2 ). The output of load cell  12  is monitored by a control system (not shown), which is calibrated to calculate when a predetermined fill volume (in ml) is reached. The control system then stops the air/ink evacuation (degassing) process by deactivating ink toggle supply valve  38  and activating ink toggle return value  40  when a preset weight has been reached. Accuracy of the filling/degassing process is limited by the accuracy of load cell  12  that is used to measure weight of the cartridge  10 . 
     Referring again to FIG. 4, after an accurate weight of cartridge  10  is determined, the cartridge  10  is then rotated about pivot point  30  from the vertical position  50  to the horizontal position  48 . When the cartridge  10  is in the horizontal position  48 , additional ink is pumped into the pouch  8  via ink reservoir  34  by activating ink toggle supply valve  38  and deactivating ink toggle return value  40 . 
     Referring still again to FIG. 4, after fluid has been introduced into pouch  8 , the cartridge  10  is then rotated about pivot  30  from the horizontal position  48  to the vertical position  50 . At this stage, a second evacuation step of pouch  8  takes place. It is our experience that this repeat of the fill and the air/evacuation processes is important to the invention because it improves the accuracy of cartridge filling and degassing. 
     At the conclusion of the final pouch evacuation, the cartridge  10  is again rotated in fixture  28  about pivot  30  from the vertical position  50  to the horizontal position  48 . The full pouch  8  contained in cartridge  10  is manually removed from fixture  28  and replaced by a fresh cartridge. The fresh cartridge is then filled and degassed using the same procedure described above. 
     The invention has been described with reference to a preferred embodiment. However, it will be appreciated that variations and modifications can be effected by a person of ordinary skill in the art without departing from the scope of the invention. 
     PARTS LIST 
       6  rigid frame 
       8  pouch 
       10  cartridge 
       12  load cell 
       14  gripper 
       16  slide assembly 
       18  holding member 
       20  needle 
       22  support member 
       24   a  spaced alignment member 
       24   b  spaced alignment member 
       26  septum, or fluid inlet end 
       28  fixture 
       30  fixture pivot point 
       32  bump stop 
       34  reservoir 
       36  liquid trap 
       38  ink toggle supply valve 
       40  ink toggle return valve 
       42  ink shut off valve 
       44  vacuum pump 
       46  pumping system 
       48  substantially horizontal position 
       50  substantially vertical position 
       52  terminus point of vertical rotation of cartridge  10   
       54  ink supply pump 
       100  apparatus