Abstract:
An apparatus for refurbishing used ink jet cartridges and a method for operating an ink jet cartridge refurbishment facility. The apparatus includes a number of stations and accessories that perform the recovery and filling aspects of the ink jet cartridge refurbishment process. This apparatus may be one of a number of machines used in an ink jet cartridge refurbishment facility where ink jet device users may drop-off their used ink jet cartridges and pick-up replacement ink jet cartridges at the same location that refurbished the ink jet cartridges.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application is related to United States Provisional Patent Application Ser. No. 60/482,052 filed Jun. 24, 2003, and entitled, APPARATUS AND METHOD FOR REFURBISHING USED CARTRIDGES FOR INK JET TYPE IMAGING DEVICES. The Applicants claim the benefit of this prior provisional application under 35 U.S.C. §119(e). The entire contents of this provisional application is incorporated herein by this reference. 

   TECHNICAL FIELD OF THE INVENTION 
   The invention is directed to the refurbishment of ink jet cartridges used in ink jet type imaging devices such as printers, photocopiers, and facsimile machines, for example. The invention encompasses devices for refurbishing used ink jet cartridges and business methods for the convenient recycling of used ink jet cartridges. 
   BACKGROUND OF THE INVENTION 
   Ink jet imaging devices produce text and images on a substrate such as paper by ejecting minute quantities of ink from a reservoir onto the substrate in response to electrical commands. The electrical commands activate small orifices or ink jets in a print head to eject the ink in the desired locations to form the desired images. Because the ink in an ink jet imaging device is used up eventually in the printing process, conventional ink jet imaging devices include the ink reservoir in a replaceable cartridge commonly referred to as an ink jet cartridge. The print head containing the orifices through which the ink is ejected is also commonly included in the replaceable ink jet cartridge. The remainder of the ink jet imaging device includes electrical control components and mechanical components for moving the ink jet cartridge with respect to the printing substrate (paper) and for moving the substrate with respect to the ink jet cartridge. 
   Photocopiers, printers, plotters, and facsimile machines are examples of devices that may utilize an ink jet printing or imaging process. As used in this disclosure “ink jet device” encompasses any type of device using an ink jet process. Also, for purposes of the following description, the portion of the ink jet device other than the ink jet cartridge will be referred to herein simply as an ink jet device whether or not the ink jet cartridge is installed. The portion of the ink jet device that carries the consumable ink for the ink jet imaging process will be referred to as an “ink jet cartridge” or “cartridge” regardless of the particular design and regardless of the other components included on the device such as a print head and associated electrical lines and contacts. 
     FIG. 1  is a view in perspective of a typical prior art ink jet cartridge  100  with the bottom of cartridge  100  shown face up. Ink jet cartridge  100  includes a container  101  adapted to contain a supply of ink (the ink not being shown in the figure). The bulk of container  101  is generally rectangular in shape with a lower portion  102  projecting from the rest of the container. Print head assembly  104  is located on lower portion  102  of container  101  and includes a large number of minute, electrically stimulated orifices or ink jets  105  through which ink from container  101  is ejected in the printing process. It will be appreciated that the orifices or ink jets are shown diagrammatically in  FIG. 1  in an exaggerated scale, and that the orifices are in fact very small in order to produce the desired image resolution. The commands or electrical stimuli required to operate the orifices or ink jets  105  are applied to print head assembly  104  through electrical conductors  106  which terminate at contact pads  107  on a side of container  101 . An ink jet printing device in which cartridge  100  is to be used will include a corresponding set of electrical contacts exposed so as to make contact with contact pads  107  on the cartridge. The electrical signals required for operating print head assembly  104  originate from a print control system (not shown) included in the ink jet imaging device. The illustrated prior art ink jet cartridge  100  also includes additional orifices facilitating fluid communication to ink container  101 . The first additional orifice comprises an opening  109  commonly referred to as a vent opening or vent hole. The second additional orifice comprises an opening which is commonly referred to as a maze opening or maze hole located on the surface of cartridge  100  indicated by arrow  112 . The maze hole is associated with a ball that functions as a check valve to prevent the flow of material out of container  101 . 
   Due to space limitations and other physical restrictions in ink jet devices, ink jet cartridges typically have a relatively limited supply of the ink for use in the ink jet printing process. The working life of the print head assembly of an ink jet cartridge is, in fact, commonly much greater than the working life of the ink supply in the cartridge. Thus, although original equipment manufacturers may prefer for ink jet device users to use totally new ink jet cartridges due to the relatively high profit margins associated with selling new ink jet cartridges, it is commonly possible to refurbish and reuse ink jet cartridges many times before they are no longer serviceable. Due to the popularity and low cost of ink jet devices, the sale of both new and used ink jet cartridges has become a very big business. 
   SUMMARY OF THE INVENTION 
   The present invention includes an apparatus for refurbishing used ink jet cartridges and a method for operating an ink jet cartridge refurbishment facility. The apparatus includes a number of stations and accessories that perform the recovery and filling aspects of the ink jet cartridge refurbishment process. This apparatus may be one of a number of machines used in an ink jet cartridge refurbishment facility where ink jet device users may drop-off their used ink jet cartridges and pick-up replacement ink jet cartridges at the same location. 
   A method embodying the principles of the invention includes directly receiving used ink jet cartridges from ink jet device users and returning replacement ink jet cartridges to the respective inkjet device users. As used in this disclosure, an “inkjet device user” or “user” includes anyone that owns or operates an ink jet device. Inkjet device users may deposit their used ink jet cartridges and retrieve replacement ink jet cartridges at the same ink jet cartridge refurbishment facility where the used ink jet cartridges went through the refurbishment process. Additionally, the replacement ink jet cartridges returned to the ink jet device users may be the same ink jet cartridges deposited by the respective ink jet device users or they may be different ink jet cartridges. In a situation where an ink jet cartridge received from an ink jet device user cannot be refurbished, the ink jet cartridge refurbishment facility may sell a new or previously refurbished ink jet cartridge to the user. Implementing the methods according to the present invention avoids the time and expense involved with sending the used ink jet cartridges to a central refurbishment facility. In addition, ink jet device users are able to save money by maximizing the life of an ink jet cartridge and avoid the costs associated with buying a new cartridge each time the ink runs out. 
   Used ink jet cartridges may be refurbished with an apparatus that includes ink recovery stations, an ink clean/fill station, and fill guns. The ink recovery stations remove any excess ink from the used ink jet cartridges and the fill guns supply ink to the empty used ink jet cartridges. The ink clean/fill station may be used to both drain excess ink and then re-fill a used ink jet cartridge. An apparatus according to the present invention may also include a pressure equalization station that equalizes the pressure in a used ink jet cartridge that has been re-filled. The variety of stations included with the apparatus according to the invention together with the various fill arrangements included in the system allows the apparatus to refurbish almost any type of ink jet cartridge. 
   The ink recovery stations, the ink clean/fill station, and the pressure equalization station operate using a vacuum source to perform their respective functions. A pressurized air distribution network and series of vacuum ejectors supply the vacuum necessary for these respective stations to work properly. The pressurized air distribution network includes several control valves that receive pressurized air from a common source. The air that enters the control valves exits through outlet tubes that are each connected to a vacuum ejector. Each vacuum ejector is connected to a vacuum fitting that corresponds to one of the ink recovery stations, the ink clean/fill station, or the pressure equalization station. The vacuum applied at the respective station either removes ink from a used ink jet cartridge, equalizes the pressure in a re-filled ink jet cartridge, or draws ink into an empty used ink jet cartridge. 
   The pressurized air distribution network may receive air from an external source or from an onboard compressor that is mounted within the housing of the apparatus of the present invention. The external source or the onboard compressor may be connected to a switching device that includes a first connector that is associated with the onboard compressor adjacent to a second connector that is associated with the external source. The switching device is connected to a pressure regulator that distributes regulated air to the pressurized air distribution network from either the external source or the onboard compressor. 
   Another aspect of the apparatus according to the invention is a fill gun control unit. The fill gun control unit includes ink pumps that are each used to supply ink to a respective fill gun. The ink pumps are driven by their own motor through a controller unit. When a particular fill gun is activated using the associated start switch, ink flows from the corresponding ink pump through an ink supply line to the fill gun for an amount of time set on the timer associated with the particular fill gun or until the operator activates the kill switch located on the fill gun to stop the flow of ink. 
   These and other advantages and features of the invention will be apparent from the following description of the preferred embodiments, considered along with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a view in perspective of a prior art ink jet cartridge of a type that may be refurbished according to the present invention. 
       FIG. 2  is a front perspective view of an ink jet cartridge refurbishing system embodying the principles of the present invention. 
       FIG. 3  is a front view of the ink jet cartridge refurbishing system shown in  FIG. 2  with the cabinet door removed. 
       FIG. 4  is a diagrammatic representation of the ink jet cartridge refurbishing system shown in  FIG. 2 . 
       FIG. 5  is a view in longitudinal section of a recovery cradle used in the system shown in  FIG. 2 . 
       FIG. 6  is a partially cut away side view of a cleaning and filling cradle used in the refurbishing system shown in  FIG. 2 . 
       FIG. 7  is a side view showing a preferred cradle attachment arrangement that may be used for one or more cradles in the refurbishing system shown in  FIG. 2 . 
       FIG. 8  is a side view of a first cradle attachment component. 
       FIG. 9  is a top view of the first cradle attachment component. 
       FIG. 10  is a front view of the first cradle attachment component. 
       FIG. 11  is a side view of a second cradle attachment component. 
       FIG. 12  is a top view of the second cradle attachment component. 
       FIG. 13  is an exploded side view of the cradle and cradle attachment arrangement shown in  FIG. 7 . 
       FIG. 14  is a mostly diagrammatic representation of one of the ink jet cartridge filling guns included in the ink jet cartridge refurbishing system shown in  FIG. 2 . 
   

   DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIGS. 2 through 4  illustrate an ink jet cartridge refurbishing system  200  embodying the principles of the invention, while  FIGS. 5 through 14  illustrate various components of the system. Referring first to the overall system views in  FIGS. 2 and 3 , ink jet cartridge refurbishing system  200  embodying the principles of the invention includes a lower cabinet generally shown at reference numeral  201  and an upper cabinet generally shown at reference numeral  202 . Suitable casters preferably support lower cabinet  201  so that the system may be moved easily from location to location and then preferably locked in place. Lower cabinet  201  includes a first compartment  203  accessible through a cabinet door  204  shown in  FIG. 2 . Lower cabinet  201  also includes a second compartment  205  located below the first compartment. The top of lower cabinet  201  defines a work shelf  206 . Upper cabinet  202  includes a front panel  207 . Lateral sides  208  of upper cabinet  202  provide support surfaces for four separate ink jet cartridge filling guns  209 , each with a separate receptacle or holster  210 . One lateral side  208  also provides a location for a pressurized air fitting  211  adapted to provide air to utility air tool  212 . The opposite lateral side  208  of upper cabinet  201  provides a location for a vacuum line fitting  213  adapted to connect with a vacuum application tool  214  (shown in  FIG. 3 ). 
   As shown best in  FIG. 3 , the first compartment  203  of lower cabinet  201  provides a storage area for miscellaneous parts, equipment, and accessories. First compartment  203  also provides a location for storing ink reservoirs  300  for the various ink jet cartridge filling devices included in system  200  and one or more waste ink or recovered ink reservoirs  301  for receiving ink recovered from used ink jet cartridges in the course of refurbishment. All of these reservoirs are preferably contained in a tub  302  that provides secondary containment in the event of spills or overflows from the reservoirs. First compartment  203  also houses a pressure regulator  303  for regulating air pressure to the various components of the system  200  that require air pressure for operation. A quick connect fitting  304  is preferably associated with the inlet to pressure regulator  303 . 
   Second compartment  205  is shown in the illustrated form of the system located below the first compartment  203 . This compartment provides the preferred location for housing an onboard compressor  306  and motor  307  for driving the air compressor, although other forms of the invention may include the onboard compressor and compressor motor elsewhere in the system. The figures omit the motor controller and electrical connections associated with the motor so as not to obscure the invention in unnecessary detail, however, such controls and electrical lines will be included with the motor  307 . This onboard compressor  306  provides sufficient air volume at the desired pressure to operate any of the various air pressure operated components of system  200 . This onboard air capability is what allows system  200  to be placed in retail establishments as will be described below. 
   As indicated in  FIG. 3 , the preferred system  200  also provides a fitting  309  for accepting air pressure from an external source. This external source may be a large volume source that is capable of providing sufficient volume at the desired pressure to simultaneously operate substantially all of the air pressure driven components in system  200 . In the preferred form of the invention, onboard compressor  306  supplies air through a hose  311  which is connected at its end to run parallel to a hose  312  that carries air from the external fitting. Each of these two hoses includes a respective quick connect connector  313  and  314  that is adapted to connect with quick connect fitting  304  associated with pressure regulator  303 . An operator may switch back and forth between the onboard compressor  306  and external pressure source by connecting the appropriate hose  311  or  312  to the regulator fitting  304 . Alternatively, conduits from both the onboard compressor  306  and external air fitting  309  may be routed to a suitable switching device (not shown) for switching between the two sources for application through pressure regulator  303 . 
   Work shelf  206  defined by the upper surface of lower cabinet  201  provides a convenient location for holding various accessories and equipment that may be used by the system operator in performing the various refurbishing functions that may be performed with system  200 . Front panel  207  of the upper cabinet  202  includes a number of different stations for performing refurbishing operations on ink jet cartridges. The illustrated form of the invention includes seven ink recovery stations each shown generally at reference numeral  317 , one pressure equalization station  318 , and one ink clean/fill station  319 . Each of these stations operate using at least one vacuum connection. The required vacuum is supplied from a respective vacuum fitting  322  on front panel  207  through a respective vacuum hose  323 . As will be discussed below with reference to  FIG. 6 , the ink clean/fill station  319  uses two separate vacuum connections and an ink supply connection. The required vacuum is created in each instance with a venturi effect device as will be discussed further below with reference to  FIG. 4 . 
   The various stations included in system  200  allow the system to refurbish substantially any type of ink jet cartridge. The specific refurbishment process varies from one cartridge to another, however, the various stations accommodate each process step. In some cartridges, it is necessary or desirable to completely remove any ink remaining in the cartridge or the remnants of any cleaning material that may have been injected in the cartridge. Ink or other liquid remnant removal may be accomplished in many cartridges using one of the recovery stations adapted for the particular cartridge. The cartridge is inserted into a cradle associated with the ink recovery station  317  in an operating position and then the vacuum is applied to withdraw the desired fluid from the cartridge. Other types of cartridges require a vacuum to be applied at a particular top opening in order to equalize the pressure in the cartridge and allow it to function properly. This pressure equalization is accomplished using pressure equalization station  318 . Still other types of cartridges may be cleaned and filled in a single step in system  200  using ink clean/fill station  319  as will be described below. 
   Front panel  207  includes a number of switch actuators for controlling a switch mounted in the upper cabinet  202  behind the panel. A master switch actuator  325  controls the position of a compressor master switch and a number of vacuum control actuators  326  control the position of vacuum control switches. These switches will all be illustrated and described in connection with  FIG. 4 . Also visible in  FIG. 3  are four fill gun switch actuators  327  and four timers  328  for controlling operation of the respective fill guns  209 . The lateral sides  208  of upper cabinet  202  also provide a convenient location for fittings for a positive air pressure hose and utility air tool  212  a vacuum hose and vacuum application tool  214 . 
   In order to allow system  200  to refurbish substantially any type of ink jet cartridge, the system includes a second type of ink jet cartridge filling arrangement in addition to the clean/fill station  319  mounted on front panel  207 . This second type of ink jet cartridge filling arrangement includes the four separate fill guns  209  mounted on the lateral sides  208  of upper cabinet  202 . The four separate guns  209  are required for the four different colors of ink used in current ink jet cartridges. One fill gun is connected to a supply of black ink, a second fill gun is connected to a supply of blue ink, the third fill gun is connected to a supply of red ink, and a fourth fill gun is connected to a supply of yellow ink. It should be noted that the ink supplies for each of the fill guns are preferably located in the first compartment  203  of lower cabinet  201  as shown in  FIG. 3 . Each of the fill guns  209  is adapted to be stored in a respective one of the holsters  210  (shown in  FIG. 2 ) mounted on the lateral side  208  of upper cabinet  202 . Each holster preferably is tilted downwardly and includes an overflow conduit (shown in  FIG. 2 ) connected at its lowermost end to collect any overflow ink and direct it to one of the recovery ink reservoirs. As will be described in detail below with reference to  FIGS. 4 and 14 , each of the fill guns  209  is adapted to measure a desired amount of ink into an ink jet cartridge to refill the empty ink jet cartridge. 
     FIG. 4  provides a diagrammatic representation of the various internal components of ink jet cartridge refurbishing system  200  including the internal components associated with each fill gun  209  and the internal components associated with the various stations  317 ,  318 , and  319  mounted on front panel  207 . All of the vacuum operated portion of system  200  may be described with reference to the bottom portion of  FIG. 4 . The fill gun related components are shown in the upper portion of the figure. 
   Referring first to the pressurized air distribution network of system  200  in the lower half of  FIG. 4 , onboard air compressor  306  driven by compressor motor  307  provides pressurized air to produce the required vacuum by venturi effect. Air from compressor  306  is supplied through conduit or hose  311 . Air that may be supplied from an external source through external source fitting  309  is directed through conduit or hose  312 . Both hoses preferably terminate in a respective quick connect fitting  313  and  314 , both of which are adapted to connect to a fitting  304  associated with pressure regulator  303 . Connector  313  associated with hose  311  is connected to regulator fitting  304  when onboard compressor  306  supplies air for system  200 . Alternatively, connector  314  associated with hose  312  is connected to regulator fitting  304  when air is to be supplied from the external source. 
   Pressure regulator  303  regulates the supplied air to the desired constant pressure for operating the various vacuum generating venturi devices described below. Various conduits distribute the regulated pressurized air to the venturi devices, known as vacuum ejectors, and controls associated with those devices. One conduit  400  runs to a vacuum tool ejector  401 . The vacuum tube  402  extending from vacuum tool ejector  401  provides a vacuum for the vacuum application tool. Another conduit  403  provides air pressure for the utility air tool. A separate distribution conduit  405  is provided for each station in system  200  requiring a vacuum source. Distribution conduits  405  are shown in  FIG. 4  as extending from a common manifold  406 , although any suitable distribution arrangement may be employed. The distal end of each station distribution conduit  405  is connected to a respective control valve  408 . These valves are operated by the vacuum control actuators  326  mounted on front panel  207  as shown especially in  FIG. 3 . Each control valve  408  is adapted to alternatively block the flow of air to its respective two outlet tubes  409  and  410  or to direct air to either one of the associated outlets. No control valve is shown as being associated with the conduit  400  for supplying air to operate the vacuum application tool, however, other forms of the invention may include a suitable valve for enabling or disabling the vacuum application tool. 
   Each outlet tube  409  and  410  is associated with a respective vacuum ejector  411 . Each vacuum ejector creates a vacuum at vacuum tube  412  as the pressurized air flows straight through the ejector from the respective outlet tube to a respective exhaust tube  413 . Thus, when a particular control valve  408  is switched to allow air to flow through a particular outlet tube  409  or  410 , the air passing through the main path of the respective vacuum ejector  411  creates the desired vacuum in tube  412 . Each vacuum tube  412  extends to a respective one of the vacuum fittings  322  mounted on front panel  207  (shown in  FIG. 3 ). Each exhaust tube  413  extends to one of the recovered ink reservoirs included in the system as shown in  FIG. 3 . It will be noted that the illustrated system  200  includes a total of nine stations and thus one of the control valves includes only a single outlet tube  409 . 
   Referring now to the upper portion of  FIG. 4 , four separate control units  415  are provided for the four separate fill guns  209  shown in  FIG. 3 . Each control unit  415  includes a separate ink pump  417  driven by a respective motor  418  through a respective motor controller  419 . Each pump  417  preferably includes a peristaltic pump, receives ink from a respective ink supply  420 , and directs ink through ink tube  421  that terminates in a suitable fitting  422  on an external surface of system  200 . In the illustrated form of the invention the ink outlet fittings  422  are mounted on the lateral sides  208  of upper cabinet  202  as indicated in  FIG. 2 . Each controller  419  for the respective pump motor  418  includes a number of electrical control lines that extend to switches mounted on the respective fill gun as will be described further below with reference to  FIG. 14 .  FIG. 4  shows a separate control line  423  for a kill switch and a separate control line  424  for a fill gun start switch. In the preferred form of the invention, the electrical control lines extend from the controller  419  to a suitable fitting  426  on an external surface of upper cabinet  202 . A suitable connecting line connects to these fittings  426  and extends to the respective fill gun as will be described below with reference to  FIG. 14 .  FIG. 4  also shows that each controller  419  is associated with a respective timer  428  and a respective power switch  429  connected to a suitable electrical power supply (not shown in  FIG. 4 ) for driving the respective pump motor  418 . As will be described further below, each timer  428  is used to control the respective pump  417  to supply a desired volume of ink to fill an ink jet cartridge being refurbished. 
     FIG. 5  shows an ink recovery station  317  included on the front panel  207  of refurbishing system  200 . Ink recovery station  317  includes a fitting or receiver referred to as a cradle  501  that is adapted to receive a particular type or style of ink jet cartridge. Cradle  501  snugly receives the particular type of ink jet cartridge (not shown in  FIG. 5 ) with a desired component on the cartridge, normally the print head, aligning with a vacuum sealing element  502  on an inner surface of the cradle  501 . The vacuum sealing element  502  is associated with an opening  503  in the cradle and a fitting  504  to which a connecting vacuum hose  323  (also shown in  FIG. 3 ) may be connected. It will be appreciated that each cradle is specifically adapted for a particular type of ink jet cartridge. It should also be noted that when vacuum sealing element  502  is adapted to seal against a printhead, the vacuum sealing element preferably overlaps with a peripheral portion of the plate commonly associated with a printhead so that the vacuum is not allowed to pull the printhead plate from its position on the ink jet cartridge. 
   In order to accommodate the relatively wide variety of different types of ink jet cartridges, the illustrated system  200  includes the seven different ink recovery stations. System  200  includes one pressure equalization station ( 318  in  FIG. 3 ) which is similar to the ink recovery station  317  except that the vacuum is applied to a top part of the cartridge. This application of a vacuum to a top opening of a particular type of cartridge using an equalization vacuum sealing element with the cartridge in a pressure equalizing position is required to equalize pressure in the cartridge after it has been refilled. 
     FIG. 6  shows the cradle  601  associated with the ink clean/fill station  319  shown in  FIG. 3 . This particular station is adapted to clean and fill a popular type of ink jet cartridge using a particular cleaning and filling technique. Clean/fill cradle  601  includes a stationary component  602  and a sliding component  603 . Sliding component  603  is adapted to slide up and down with respect to stationary component  602  as indicated by arrow  604 . In an upper position, the sliding component  603  presses an ink jet cartridge received in the cradle against an upper part of the stationary component  602  to provide seals against two upper sealing elements  605  and  606 . A seal is also produced in a resilient material  607  lining the upper surface of sliding component  603 . A vacuum is required at two different points in cradle  601 . Thus, it will be noticed in  FIG. 4  that one of the control valves  408  directs air through two separate vacuum ejectors  411 . The vacuum from one ejector is applied through tube  610  to the sliding component of cradle  601 . The vacuum from the other ejector is applied to the stationary component  602  of cradle  601  through tube  611 . Cradle  601  is also connected to an ink fill tube  612  which ultimately extends to an ink supply reservoir preferably mounted in lower cabinet  201 . In the particular type of ink jet cartridge with which clean/fill cradle  601  is adapted to be used, the used cartridge is placed in the cradle in a clean/fill position so that the ink fill tube  612  and associated ink fill sealing element  605  aligns with a vent opening ( 109  in  FIG. 1 ), the upper vacuum supply tube  611  and associated print head sealing element  606  aligns with the printhead ( 104  in  FIG. 1 ) of the cartridge, and the lower vacuum supply line  610  applies a vacuum to the maze opening ( 110  in  FIG. 1 ) of the cartridge through a maze vacuum sealing element. The vacuum applied to the maze opening ensures that the valve associated with the maze opening stays closed while the vacuum applied through the printhead draws ink into the reservoir through the ink fill tube  612  and cartridge vent opening. It will be noted that the resilient material  607  on slide component  603  is permeable so that the vacuum may be applied to the cartridge maze opening. 
   Referring now to  FIG. 7 , the cradle associated with at least each ink recovery station and the pressure equalization station ( 317  and  318 , respectively in  FIG. 3 ) on system  200  is preferably attached to front panel  207  with a cradle attachment  701  that allows the respective cradle to be removed and replaced with a different cradle as necessary to accommodate different types of ink jet cartridges. The preferred cradle attachment  701  includes a first component  702  which is adapted to be attached to front panel  207  at a suitable location for the station near the vacuum fitting  322  (shown in  FIG. 3 ) associated with the respective station. This first component  702  is shown particularly in  FIGS. 8 through 10 . A second component  703  of cradle attachment  701  is adapted to be connected to a back surface of the respective cradle and cooperates with first component  702  to produce a secure but easily releasable attachment between the cradle and front panel  207 . This second component  703  is illustrated particularly in  FIGS. 11 and 12 . 
   As shown in  FIGS. 8 through 10 , first component  702  of cradle attachment arrangement  701  includes a block of material having a receiving slot  705  (shown in  FIG. 9 ) formed therein. Receiving slot  705  includes a top opening  706  and terminates at the opposite end of first component  702  with a support member  707 . It will be noted particularly from the top view of  FIG. 9  that receiving slot  705  includes generally a T-shaped cross-section.  FIG. 10  shows that the base of the T-shape comprises a front opening  709 . Although any suitable connector may be used, in the preferred form of the invention first component  702  is connected to front panel  207  with bolts and thus includes bolt holes  708  through which the connecting bolts may extend. 
   Referring now to  FIGS. 11 and 12 , second component  703  of cradle attachment arrangement  701  includes an elongated member having a generally T-shaped transverse shape as shown best in  FIG. 12 . This T-shape corresponds generally to the transverse shape of receiving slot  705 . Second component  703  is adapted to be bolted to a cradle and thus also includes bolt holes  712 , although the invention is not limited by the manner in which second component  703  is connected to the cradle. In fact, the cradle and second attachment component may be integrally formed. 
     FIG. 13  shows first component  702  secured in an appropriate position on front panel  207  and second component  703  secured to the back surface of a cradle. The cradle may be secured to panel  207  by first positioning the cradle and attached second component  703  above the first component  702  as shown in  FIG. 13 . From this point, the cradle and second component  703  may be moved along a line indicated by arrow  1301 . Eventually the T-shaped second component  703  slides into the correspondingly shaped slot  705  (shown in  FIG. 9 ) until the components reach the position shown in  FIG. 7 . In this position, the cradle is securely attached to front panel  207  and may receive an ink jet cartridge for a desired refurbishment operation. However, the cradle may be removed easily by simply sliding it upwardly in a direction opposite to that indicated by arrow  1301  until the T-shaped second component  703  clears slot  705 . Another different cradle with the same type of second component connected thereto may then be slid into the first component  702  to accept a different type of ink jet cartridge as necessary. 
     FIG. 14  shows a somewhat diagrammatic representation of one of the fill guns  209  described above especially in  FIGS. 2 and 3 . The fill gun  209  includes a handle or pistol-type grip  1401  and a fill needle  1402 . The gun also includes a fitting  1403  for making a connection with an ink supply line/electrical control line  1407 . An ink conduit  1404  extends from fitting  1403  to a proximal end of fill needle  1402 . Preferably a suitable check valve  1405  is included in this conduit  1404  to prevent ink from flowing back in the direction from the fill gun to the ink supply line/control line  1407 . Fill gun  209  also includes two switches, a start switch  1409  and a kill switch  1410 . Start switch  1409  is activated through a trigger actuator  1411 , while kill switch  1410  is activated through a separate button actuator  1412 . 
   The operation of fill gun  209  may now be described with reference to  FIGS. 14 and 4 . In order to fill an empty ink jet cartridge with fill gun  209 , the operator first withdraws the fill gun  209  from its respective holster  210  on system  200  and inserts the distal end of the needle  1402  into an orifice on the particular ink jet cartridge. The operator also sets the timer  428  associated with fill gun  209  to run the associated pump for a particular time. Since pump  417  runs at a known speed and moves a known volume of ink in any given time, setting timer  428  has the effect of setting the volume of ink to be supplied to the cartridge. Once timer  428  is set and the needle is appropriately placed in the empty ink jet cartridge, the operator depresses the trigger actuator  1411  to trip the start switch  1409 . The controller  419  associated with the pump  417  uses the signal generated at the start switch to start motor  418  and cause pump  417  to start dispensing ink through needle  1402 . The motor  418  continues to run until the timer  428  runs down to zero at which point the timer signals motor controller  419  to stop the motor and thus the flow of ink into the cartridge. At any point in the process the operator may depress the kill switch actuator  1412  to provide a signal to the motor controller to stop the motor before receiving a signal from the timer. The user may wish to do this for example when the needle proves to be incorrectly placed in the ink jet cartridge and ink does not flow into the cartridge as desired. 
   Although the illustrated form of the invention includes timers for measuring the volume of ink supplied to fill the ink jet cartridge, other forms of the invention may use different arrangements for metering the volume of ink into a cartridge. For example, the volume of ink supplied to refill a cartridge may be measured directly from a suitable positive displacement pumping device. 
   The self-contained ink jet cartridge refurbishing system  200  described above has particular application in a retail ink jet cartridge refurbishing facility. Because the system  200 , with its various stations, various cradles, and multiple filling arrangements is specifically adapted to be able to refurbish substantially any ink jet cartridge, the system can be employed in a retail arrangement in which a user brings their used cartridge to the retail refurbishing center, drops the cartridge off for refurbishment, and then later picks up the refurbished cartridge after the cartridge has been refurbished at the retail location. This is in contrast to prior ink jet cartridge refurbishing systems in which the cartridge had to be sent away to a central refurbishing facility. In another variation of the refurbishment arrangement, the ink jet device user may trade in their used cartridge for a refurbished cartridge. An operator then uses the system  200  to refurbish the used cartridge and make it available to another customer dropping off a like cartridge. 
   In any refurbishment application, retail or production, certain additional equipment may be required to ensure the refurbished cartridge is in a usable state. For example, a testing unit such as Makro Micro Company, Croatia, Model CT8 or CT56 may be used to test each refurbished cartridge to ensure it is in proper working order prior to distribution to a customer or return to the user who dropped off the cartridge for refurbishment. 
   The above described preferred embodiments are intended to illustrate the principles of the invention, but not to limit the scope of the invention. Various other embodiments and modifications to these preferred embodiments may be made by those skilled in the art without departing from the scope of the following claims.