Abstract:
The present invention provides a method and an apparatus for filling ink-jet cartridges with ink. Ink-jet cartridges are commonly refilled with ink while under a vacuum, to facilitate completely filling a reservoir or foam insert within the cartridge. However, when the cartridge is subsequently submitted to atmospheric pressure, a significant amount of ink is suctioned out of the cartridge, creating a mess and leaving the cartridge less than full. The instant invention results in a fully refilled ink cartridge, without leaking ink, by timed release of the vacuum during the ink filling process.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates generally to a method of and apparatus for filling ink-jet type ink cartridges. 
         [0003]    2. Description of the Prior Art 
         [0004]    Ink-jet cartridges are commonly refilled with ink to enable the cartridge to be recycled for further use, rather than being disposed of and replaced at an additional expense. A number of methods of refilling ink cartridges are known in the prior art. Some of these methods involve placing the cartridge in a vacuum chamber where it is submitted to lower than atmospheric pressure, thereby eliminating air from the interior of the cartridge and expanding and opening the pores of a foam or sponge inside the cartridge. Ink can then be pumped into the cartridge through one or more hoses leading from a supply of ink outside the vacuum chamber, or may be introduced into the cartridge by one or more syringes. Although single color ink cartridges can be refilled with a single hose or syringe, multi-color cartridges require multiple hoses or syringes, allowing separate reservoirs within the cartridge to be filled with cyan, magenta, yellow, and black ink, or some other combination of possible colored inks. 
         [0005]    Each color reservoir within an ink-jet type cartridge typically contains foam or a sponge, suitable for soaking and storing ink. Each reservoir is capable of holding more ink, while subjected to a vacuum, than when the cartridge is at atmospheric pressure. Thus, submitting the cartridge to a vacuum facilitates refilling the cartridge with ink, but commonly results in some of the ink leaking out of the cartridge when the cartridge is returned to atmospheric pressure. This creates a significant disadvantage of refilled cartridges when compared to cartridges that have been filled in the process of making the cartridge, and thus an impediment to recycling ink-jet cartridges. A refilled cartridge typically has an amount of ink which is less than capacity, and potentially less than a new cartridge, since some of the ink leaked out of the cartridge in the refilling process. Furthermore, the recycled cartridge may be messy to utilize, as a result of leaked ink on the exterior of the cartridge. 
         [0006]    Examples of cartridge refilling methods known in the prior art include U.S. Pat. No. 6,733,115 to Santhanam et al., and a related pending application 2002/0196317. In the process taught in those documents, a vacuum is applied to the nozzle array of the print head nozzle during the procedure of filling the cartridge. Similarly, U.S. Pat. No. 5,801,735 to Lorenze, Jr. et al., requires a pressure gradient between a refill ink container and print head nozzles during refilling. U.S. Pat. No. 6,116,719 to Maza teaches an ink replenishment system in which vacuum pressure is used to move ink from a reservoir into a pen cartridge. 
         [0007]    U.S. Pat. No. 5,459,497 to Manning et al. describes a process in which a pump is used to pressurize ink and air during a refilling process. Similarly, U.S. Pat. No. 6,796,627 to Kimura et al. requires pressurization of air and ink during refilling and U.S. Patent Application 2005/0024423 requires a positive-pressure supply to apply positive pressure on ink. The refilling device of U.S. Patent Application 2005/0243150 requires ink to be supplied under pressure to fill a cartridge chamber. 
         [0008]    U.S. Pat. No. 7,008,038 to Takagi et al. and related application 2004/0075710 teach a cartridge refilling process which is accomplished through the print head of the cartridge. European Patent Application EP 1661710A2 describes a cartridge refilling process in which liquid is injected through an air discharge opening made open in an injection hole film piercing process. 
         [0009]    The difficulty in completely filling an ink jet cartridge is discussed in U.S. Patent Application 2002/0012032. This patent application proposes a specialized cartridge including a penetrable diaphragm to alleviate the problem. 
         [0010]    The invention described herein is a device and process enabling typical ink-jet type cartridges to be completely filled with ink, without loosing ink when the cartridge is removed from a vacuum chamber and returned to atmospheric pressure. As a result, the process avoids the mess created by many refilling processes, and results in the maximum possible amount of ink being available for use in the recycled cartridge. 
       SUMMARY AND OBJECTS OF THE INVENTION 
       [0011]    A primary object of the present invention is to provide a method and process for refilling ink-jet type cartridges to provide a maximum amount of ink in the recycled cartridge. 
         [0012]    Another object of the present invention is to refill an ink-jet cartridge in a manner that prevents ink from spontaneously leaking out of the cartridge. 
         [0013]    These objects are achieved by removing air from an ink-jet type cartridge to create a vacuum, pumping ink through an ink filling pathway leading into the cartridge, and then releasing the vacuum by infusing air into the cartridge while ink is being pumped into the cartridge. While ink is commonly delivered into an ink-jet cartridge while the cartridge is under a vacuum, processes known in the prior art typically do not release the vacuum until after the ink filling process has been completed. By releasing the vacuum at a desirable time during the filling process, over-filling of the cartridge is avoided, and ink is not pushed out of the cartridge when the cartridge is returned to atmospheric pressure after filling. 
         [0014]    The device used in the claimed process of refilling ink-jet type cartridges includes a vacuum chamber in which the cartridge can be secured. A clip suitable for holding a cartridge in place may be fastened to the interior floor or wall of the vacuum chamber, or the interior cavity of the vacuum chamber may be shaped and sized so as to securely hold a cartridge of a particular type when that cartridge is placed in the chamber. Ink filling pathways, such as hoses or syringes, can be inserted through holes in the wall of the vacuum chamber, in sealed fashion allowing a vacuum to be maintained within the chamber. These pathways provide a conduit for ink from a reservoir of ink on the outside of the chamber, into the cartridge placed in the vacuum chamber. Each pathway can beneficially be fitted with a flow restriction valve which allows ink to flow only in the direction of the cartridge, and only when a desired pressure is applied to ink in the ink reservoir. Pressure can be applied to the ink through a typical pump or by mechanically pushing a plunger in a syringe-type drive device 
         [0015]    Once the cartridge is secured within the vacuum chamber, air is evacuated from the chamber to create a vacuum within the chamber. Air is thus removed from the cartridge, allowing the pores of foam within the cartridge to expand and open, enabling more ink to be received than when the foam was at atmospheric pressure. While the pressure within the chamber and the cartridge is lower than atmospheric pressure, ink is pushed into the ink filling pathway, and ultimately into the cartridge. By sealing the print head of the cartridge prior to placement in the chamber, ink can be pushed into the cartridge without leaking through the print head, in a manner that allows the print head to be primed as the cartridge is filled to capacity. 
         [0016]    In a preferred embodiment of the present invention, the vacuum within the chamber is released while the ink is being pumped into the cartridge, prior to the cartridge being filled to capacity. A timer may be utilized to initiate the infusion of air into the vacuum chamber, and thus into the cartridge within the chamber, at a desired time after ink has started filling the cartridge. Ink quickly begins to fill the cartridge while it is at less than atmospheric pressure, allowing the print head to be primed. However, the ink level is kept lower as it reaches capacity and this level is influenced when the vacuum chamber is returned to atmospheric pressure. As a result, the cartridge is completely filled, and ink is not pushed out of the cartridge as typically results from returning the cartridge to room pressure after the filling operation is complete. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is a perspective view of a device for filling an ink-jet type cartridge, with the vacuum chamber and inkjet cartridge cutaway to reveal the interior thereof, according to the present invention. 
           [0018]      FIG. 2  is a perspective view of an open device for filling a particular size and shape ink-jet type cartridge, with the vacuum chamber cutaway to reaveal the interior thereof, according to the present invention. 
           [0019]      FIG. 3  is a perspective view of a device for filling an ink-jet type cartridge utilizing syringes to fill multiple ink reservoirs, with the vacuum chamber and inkjet cartridge cutaway to reveal the interior thereof, according to the present invention. 
           [0020]      FIG. 4  is a perspective view of an ink-jet type cartridge, cutaway to reveal multiple ink reservoirs. 
           [0021]      FIG. 5  is a cutaway view of the interior of an ink dispensing syringe. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0022]    The present invention concerns a method and apparatus for refilling ink-jet type cartridges in a manner that allows the cartridges to be completely filled with ink and which avoids leaking of ink after the refilling process is completed. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be obvious, however, to one skilled in the art that the present invention may be practiced without these specific details. Some well-known methods and structures have not been set forth in order not to unnecessarily obscure the description of the present invention. 
         [0023]    As can be seen in  FIG. 1 , the ink filling device  10  claimed herein includes an ink pumping means  18 , at least one ink filling pathway  20 , a vacuum creating means  22 , and a timed vacuum releasing means  24 . An ink-jet type cartridge  12  typically has an extension which serves as a print head  14 , and a foam  64  inside the cartridge suitable for absorbing ink  16 . It is desirable to seal the print head  14  with a closure means  26  to prevent air from migrating toward the print head  14 , which could create an air bubble between ink  16  and the print head  14 . The closure means  26  can be as simple as a piece of removable tape placed over the openings in the print head  14  while the cartridge  12  is being filled. 
         [0024]    The cartridge  12  can be securely placed in the device  10  by a number of mechanisms. For example, the vacuum creating means  22  may include a vacuum chamber  44  with an interior sized and shaped to snugly receive a particular type of ink-jet cartridge  12 , as shown in  FIG. 2 . Alternatively, a more universally shaped and sized vacuum chamber  44  may be utilized, as shown in  FIGS. 1 and 3 , equipped with a cartridge cradle or clip  54  into which the cartridge  12  is inserted, which holds the cartridge  12  in place within the vacuum chamber  44  during the refilling process. While the universally shaped vacuum chamber  44  is beneficially able to accommodate a wide variety of different ink-jet cartridges, more specifically shaped vacuum chambers  44  may be easier to use, as a particular type of cartridge  12  is quickly and easily placed into and taken out of the chamber  44 , before and after refilling respectively. 
         [0025]    A vacuum may be created in the vacuum chamber  44  by evacuating air from the chamber  44  utilizing a vacuum pump  46 , as shown in  FIG. 1 . Alternatively, a vacuum may be generated by directing a large volume of compressed air through a vacuum generator  46 , also known as a venturi valve, as shown in  FIG. 3 . 
         [0026]    The claimed process can advantageously utilize a number of different ink filling pathways  20 . For cartridges  12  containing a single color of ink  16 , only one ink filling pathway  20  is required. Multiple ink filling pathways  20  may be used to fill multiple ink reservoirs  66  with different colors of ink  16 , as shown in  FIGS. 3 and 4 . An ink filling pathway  20  may advantageously consist of a syringe  42  connected to a hollow tube or hose  34 , which hose  34  is connected at an opposite end to a hollow needle  28 , as shown in  FIG. 3 . Alternatively, an ink filling pathway  20  may consist of a hollow tube or hose  34 , as shown in  FIGS. 1 and 2 , connected at one end to a pump  38  and at an opposite end to a hollow needle  28 . The hollow needle  28  is inserted into the cartridge  12 , so that a print head end  30  of the needle  28  is positioned within the cartridge  12  in proximity to the print head  14 , while the opposite end  32  of the needle  28  is attached to the hose  34 . In this manner, ink  16  may be beneficially pumped through the hollow tube  34  and into the needle  28 , pushing the ink  16  into the cartridge  12  so that ink is deposited near the print head  14 . When multiple ink filling pathways  20  are used to fill multiple reservoirs  66 , each needle  28  can advantageously be inserted into a separate reservoir  66 . 
         [0027]    As shown in  FIG. 1 , a flow restriction valve  36  may be placed along the hollow tube  34  to prevent ink  16  from migrating backwards from the cartridge  14 . This valve  36  is ideally rated for 12-20 pounds per square inch, and prevents ink  16  from moving toward the cartridge  12  until a desired pressure is applied to ink  16  in the ink flowing pathway  20 . In this manner, a pressure differential between atmospheric conditions outside the vacuum chamber  44  and vacuum conditions inside the chamber  44  will not be sufficient to cause ink  16  to flow toward the cartridge  12 , but ink  16  will be forced through the valve  36  and into the cartridge  12  when the pumping means  18  is engaged. A number of mechanisms can be beneficially used as the ink pumping means  18 . For example, as illustrated in  FIG. 1 , the ink pumping means  18  may be one or more peristaltic pumps. The pump driver (not shown) that drives the piston in the pump cylinder can either be a pneumatic air cylinder ideally set between 30 and 60 pounds per square inch or a mechanical means such as a motor driven screw through a fixed nut. When a pneumatic air cylinder is used, the ink injection flow rate is controlled by controlling the air flow rate at the air exit outlet of the pneumatic cylinder with a needle air valve. Alternatively, the pumping means  18  may consist of a volumetric dosage syringe  42  with a plunger, as shown in  FIG. 5 , which mechanically squirts ink  16  through the syringe  42  directly into the cartridge  12  (not shown), or into a hose  34  and/or needle  28  inserted into the cartridge  42 . In this embodiment, as shown in  FIG. 3 , solenoid valves  70  may advantageously control the directional flow of ink  16  through the ink pathway  20 . As the syringe  42  plunger retracts, ink  16  is drawn from an ink supply (not shown) through the valve  70  and into the syringe barrel. Then, when the plunger piston advances, the valve  70  shifts, blocking passage to the supply line and directing the flow of ink  16  from the syringe barrel down the filling pathway  20  and into the cartridge  12 . Each syringe  42  is driven by a linear actuator which may be pneumatic, mechanical, or electrical. Ink  16  can conveniently be pumped or injected into the cartridge  12  through the ink flowing pathway  20  at a flow rate of 0.5 to 2 cc per second through either type of pathway  20 . 
         [0028]    The vacuum chamber  44  can beneficially consist of a cast aluminum box capable of withstanding vacuum conditions up to 29.9 inches Hg. As shown in  FIG. 2 , a seal  60  makes the vacuum chamber  44  air tight when the door  58  is closed. A variety of different common latches  62  can be utilized to securely hold the chamber door  58  in a closed position. When the cartridge  12  has been properly positioned within the chamber  44 , a vacuum pump  46  may advantageously be used to remove air from the vacuum chamber  44 , ideally creating a vacuum of between 18 and 25 inches Hg. Pressure within the vacuum chamber  44  and lines leading from the vacuum chamber  44  to the vacuum pump  46  can be beneficially monitored by a vacuum gauge  74 . When a desired pressure is reached, a manual valve  76  may be utilized to discontinue vacuum generation, as shown in  FIG. 3 . Alternatively, as shown in  FIG. 1 , a vacuum pressure switch  68  may monitor vacuum pressure, sending an electrical signal to a solenoid valve  72  to divert vacuum generation to a bypass when the vacuum reaches a preset threshold. 
         [0029]    It is critically important that the device  10  include a vacuum releasing means  24  to restore atmospheric pressure within the vacuum chamber  44  and the cartridge  12  while ink  16  is being pumped into the cartridge  12 . At a desired time, which can advantageously be within 2 to 5 seconds after initiation of filling the cartridge  12  with ink  16 , the vacuum releasing means  24  is activated to infuse air into the vacuum chamber  44 . The vacuum releasing means  24  can conveniently be a timer  52  which actuates an air infusion means  48  at a desired time during the filling process. The air infusion means  48  can simply be a vacuum relief valve  50 , as shown in  FIG. 1 , which is opened when the timer  52  indicates the passage of the desired time, filling the vacuum chamber  44  with air. 
         [0030]    This process causes ink  16  to flow and rapidly fill the print head  14  and/or ink reservoir  66  while the cartridge  12  is under a vacuum, priming the print head  14  for use. At the same time, rapid infusion of air into the vacuum chamber  44  through the vacuum relief valve  50  restores atmospheric pressure in the cartridge  12 , keeping ink  16  from migrating to the top of the foam  64 , while allowing the foam  64  to be completely filled starting from the bottom and moving upward without overflowing through the top of the foam  64 . Because the vacuum is released prior to completely filling the cartridge  12 , the claimed process avoids ink  16  being sucked out of the cartridge  12  when the cartridge  12  is returned to atmospheric pressure. 
         [0031]    Although the present invention has been described in terms of the presently preferred embodiment, it is to be understood that such disclosure is purely illustrative and is not to be interpreted as limiting. Consequently, without departing from the spirit and scope of the invention, various alterations, modifications, or alternative applications of the invention will, no doubt, be suggested to those skilled in the art after having read the preceding disclosure. Accordingly, it is intended that the following claims be interpreted as encompassing all alterations, modifications, or alternative applications as fall within the true spirit and scope of the invention.