Abstract:
Embodiments of the present invention comprise apparatus and methods for modifying existing low cost “on-axis” ink jet printer systems to accommodate low intervention rate “free ink” ink supplies. Embodiments are disclosed which enable reduced intervention rates and visual ink level indication by providing a large ink container, flexible interconnect tubing, and a modified ink supply container which mounts to the printer carriage.

Description:
TECHNICAL FIELD OF THE INVENTION  
         [0001]    The present invention relates to an adaptor for providing ink to a printing system. More specifically, exemplary embodiments of the present invention relate to a “free ink” reservoir adaptor for an ink jet printer having on-axis ink supplies.  
         BACKGROUND OF THE INVENTION  
         [0002]    Inkjet printers typically use a printhead mounted on a carriage that is moved relative to a print media, such as paper. As the printhead is moved relative to the print media, a control system activates the printhead to deposit or eject ink droplets onto the print media to form images and text. Ink is provided to the printhead by a supply of ink that is either integral with the printhead, as in the case of a disposable print cartridge, or by a supply of ink that is replaceable separate from the printhead. With separately replaceable ink supplies, the ink supply is replaced when exhausted, and the printhead is then replaced at the end of the printhead useful life.  
           [0003]    When the ink supply is replaceable separate from the printhead, the supply may be either located on the carriage with the printhead or located remotely from the printhead (“off axis”). Locating the supply on the carriage with the printhead is generally a less expensive approach, although the quantity of ink provided with each replaceable supply is limited by the considerations of the total mass that must be moved on the carriage, and the spatial volume swept by the carriage.  
           [0004]    Locating the ink supplies on the carriage provides a cost effective printer configuration, as the cost of the ink delivery system is thereby reduced. Since the capacity of on-axis supplies are necessarily limited, however, the configuration may not be suitable for users having high-volume printing requirements and therefore needing a printer that will print for long periods unattended. Off axis low intervention rate printers exist, but generally at higher cost, due to the more expensive ink delivery system.  
           [0005]    There is therefore a need for devices which allow the use of cost effective on-axis ink jet printers in a high-volume low intervention rate environment.  
         SUMMARY OF THE INVENTION  
         [0006]    Embodiments of the present invention comprise apparatus and methods for modifying existing low cost “on-axis” ink jet printer systems to accommodate low intervention rate “free ink” ink supplies. Embodiments are disclosed which enable reduced intervention rates and visual ink level indication by providing an large ink container, flexible interconnect tubing, and a modified ink supply container which mounts to the printer carriage.  
           [0007]    Other aspects and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    [0008]FIG. 1 is one exemplary embodiment of an ink jet printing system, depicted with a cover opened to show a plurality of replaceable ink containers with which the off-axis supply adaptor of the present invention may be utilized.  
         [0009]    [0009]FIG. 2 is a simplified schematic representation of the exemplary inkjet printing system shown in FIG. 1.  
         [0010]    [0010]FIG. 3 is a greatly enlarged perspective view of a portion of a scanning carriage showing the replaceable ink containers positioned in a receiving station that provides fluid communication between the replaceable ink containers and one or more printheads.  
         [0011]    [0011]FIG. 4 is a side plan view of a portion of the scanning carriage showing guiding and latching features associated with each of the replaceable ink container and the receiving station for securing the replaceable ink container, thereby allowing fluid communication with the printhead.  
         [0012]    [0012]FIG. 5 shows an exemplary embodiment of an ink jet printing system of system modified to accommodate the off-axis supply adaptor of the present invention.  
         [0013]    [0013]FIG. 6 is a simplified exploded view illustrating an embodiment of the off-axis supply adaptor of the present invention, showing the modified ink delivery path.  
         [0014]    [0014]FIG. 7 is a simplified schematic representation further illustrating the modified ink jet printing system of FIG. 6.  
         [0015]    [0015]FIG. 8 is a simplified exploded view illustrating an alternate embodiment of the supply adaptor of the present invention, in which a large free-ink supply is carriage-mounted.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0016]    [0016]FIG. 1 is a perspective view of one exemplary embodiment of a printing system  10  shown with its cover open, that includes at least one replaceable ink container  12  installed in a receiving station  14 . With the replaceable ink container  12  properly installed into the receiving portion  14 , ink is provided from the replaceable ink container  12  to at least one inkjet printhead  16 . The inkjet printhead  16  is responsive to activation signals from a printer portion  18  to deposit ink on print media. As ink is ejected from the printhead  16 , the printhead  16  is replenished with ink from the ink container  12 . In one preferred embodiment, the replaceable ink container  12 , receiving station  14 , and inkjet printhead  16  are each part of a scanning carriage that is moved relative to a print media  22  to accomplish printing. The printer portion  18  also includes a media tray for receiving the print media  22 . As the print media  22  is stepped through a printing zone, the scanning carriage  20  moves the printhead  16  relative to the print media  22 . The printer portion  18  selectively activates the printhead  16  to deposit ink on print media  22  to thereby accomplish printing.  
         [0017]    The scanning carriage  20  is moved through the print zone on a scanning mechanism which includes a slide rod  26  on which the scanning carriage  20  slides as the scanning carriage  20  moves through a scan axis. A positioning means (not shown) is used for precisely positioning the scanning carriage  20 . In addition, a paper advance mechanism (not shown) is used to step the print media  22  through the print zone as the scanning carriage  20  is moved along the scan axis. Electrical signals are provided to the scanning carriage  20  for selectively activating the printhead  16  by means of an electrical link such as a ribbon cable  28 .  
         [0018]    It is essential for the proper operation of the printing system that, when an ink container  12  is replaced, both proper fluidic and electrical connection be established between the ink container  12  and the printer portion  18 . The fluidic interconnection allows a supply of ink within the replaceable ink container  12  to be fluidically coupled to the printhead  16  for providing a source of ink to the printhead  16 . The electrical interconnection allows information to be passed between the replaceable ink container  12  and the printer portion  18 . Information passed between the replaceable ink container  12  and the printer portion  18  can include, by way of example, information related to the compatibility of replaceable ink container  12  with printer portion  18  and operation status information such as the ink level information.  
         [0019]    New ink containers  12  are provided to the printer user with the fluid port sealed to prevent ink spillage during shipping and storage. It is critical that the fluid port be unsealed prior to installing a new ink container in the printer, since operating the printer without a reliable supply of ink can cause permanent damage of the printheads. The fluid interconnect label lock-out tab of the present invention, as will be discussed with respect to FIGS. 5 through 10, ensures that a new ink container  12  is not installed into the receiving portion  14  with the fluid interconnect seal in place.  
         [0020]    [0020]FIG. 2 is a simplified schematic representation of the exemplary inkjet printing system  10  shown in FIG. 1. FIG. 2 is simplified to illustrate a single printhead  16  connected to a single ink container  12 . The inkjet printing system  10  of the present invention includes the printer portion  18  and the ink container  12 , which is configured to be received by the printer portion  18 . The printer portion  18  includes the inkjet printhead  16  and a controller  29 . With the ink container  12  properly inserted into the printer portion  18 , an electrical and fluidic coupling is established between the ink container  12  and the printer portion  18 . The fluidic coupling allows ink stored within the ink container  12  to be provided to the printhead  16 . Upon installation of the ink container, a fluid interconnect  36  engages the fluid port  37  of the ink container, establishing fluid flow. The fluid interconnect  36  may comprise a separate manifold component on the scanning carriage  20 , as discussed below. The electrical coupling allows information to be passed between an electrical storage device  80  disposed on the ink container  12  and the printer portion  18 . The exchange of information between the ink container  12  and the printer portion  18  is to ensure the operation of the printer portion  18  is compatible with the ink contained within the replaceable ink container  12  thereby achieving high print quality and reliable operation of the printing system  10 .  
         [0021]    The controller  29 , among other functions, controls the transfer of information between the printer portion  18  and the replaceable ink container  12 . In addition, the controller  29  controls the transfer of information between the printhead  16  and the controller  29  for activating the printhead to selectively deposit ink on print media, and controls the relative movement of the printhead  16  and print media. The controller  29  performs additional functions such as controlling the transfer of information between the printing system  10  and a host device such as a computer (not shown).  
         [0022]    In order to ensure the printing system  10  provides high quality images on print media, the controller  29  may utilize parameters that are provided by the electrical storage device  80  to optimize the printer operation. Among the parameters, for example, that can be stored in the electrical storage device  80  associated with the replaceable ink container  12  are following: a date code associated with the replaceable ink container  12 , a date code of initial insertion of the ink container  12 , system coefficients, ink type and ink color, ink container size, printer model number or identification number and container usage information, just to name a few.  
         [0023]    [0023]FIG. 3 is a perspective view of a portion of the scanning carriage  20  showing a pair of replaceable ink containers  12  properly installed in the receiving station  14 . An inkjet printhead  16  is in fluid communication with the receiving station  14 . In the preferred embodiment, the inkjet printing system  10  shown in FIG. 1 includes a tri-color ink container containing three separate ink colors (cyan, magenta, and yellow) and a second ink container containing black ink. The replaceable ink containers  12  can be partitioned differently to contain fewer than three ink colors or more than three ink colors if more are required. For example, in the case of high fidelity printing, frequently six or more colors are used.  
         [0024]    The scanning carriage portion  20  shown in FIG. 3 is shown fluidically coupled to a single printhead  16  for simplicity. In the exemplary embodiment, four inkjet printheads  16  are each fluidically coupled to the receiving station  14 . In this embodiment, each of the four printheads are fluidically coupled to each of the four colored inks contained in the replaceable ink containers  12 .  
         [0025]    Each of the replaceable ink containers  12  include a latch  30  for securing the replaceable ink container  12  to the receiving station  14 . The receiving station  14  in the preferred embodiment includes a set of keys  32  that interact with corresponding keying features (not shown) on the replaceable ink container  12 . The keying features on the replaceable ink container  12  interact with the keys  32  on the receiving station  14  to ensure that the replaceable ink container  12  is compatible with the receiving station  14 .  
         [0026]    [0026]FIG. 4 is a side plan view of the scanning carriage portion  20  shown in FIG. 2. The scanning carriage portion  20  includes the ink container  12  shown properly installed into the receiving station  14 , thereby establishing fluid communication between the replaceable ink container  12  and the printhead  16 . The replaceable ink container  12  includes a reservoir portion  34  for containing one or more quantities of ink. In the exemplary embodiment, the tri-color replaceable ink container  12  has three separate ink containment reservoirs, each containing ink of a different color. The black replaceable ink container  12  is a single ink reservoir  34  for containing black ink. In the exemplary embodiment, the reservoir  34  has a capillary storage member (not shown) disposed therein. The capillary storage member is a porous member having sufficient capillarity to retain ink to prevent ink leakage from the reservoir  34  during insertion and removal of the ink container  12  from the printing system  10 .  
         [0027]    This capillary force must be sufficiently great to prevent ink leakage from the ink reservoir  34  over a wide variety of environmental conditions such as temperature and pressure changes. In addition, the capillarity of the capillary member is sufficient to retain ink within the ink reservoir  34  for all orientations of the ink reservoir as well as a reasonable amount of shock and vibration the ink container may experience during normal handling. The preferred capillary storage member is a network of heat bonded polymer fibers, although any suitable capillary material may be used.  
         [0028]    Once the ink container  12  is properly installed into the receiving station  14 , the ink container  12  is fluidically coupled to the printhead  16  by way of fluid interconnect  36 . Upon activation of the printhead  16 , ink is ejected from the ejection portion  38  producing a negative gauge pressure, sometimes referred to as backpressure, within the printhead  16 . This negative gauge pressure within the printhead  16  is sufficient to overcome the capillary force resulting from the capillary member disposed within the ink reservoir  34 . Ink is drawn by this backpressure from the replaceable ink container  12  to the printhead  16 . In this manner, the printhead  16  is replenished with ink provided by the replaceable ink container  12 .  
         [0029]    The fluid interconnect  36  of the exemplary embodiment is preferably an upstanding ink pipe that extends upwardly into the ink container  12  and downwardly to the inkjet printhead  16 . The fluid interconnect  36  is shown greatly simplified in FIG. 4. In the exemplary embodiment, the fluid interconnect  36  is a manifold that allows for offset in the positioning of the printheads  16  along the scan axis, thereby allowing the printhead  16  to be placed offset from the corresponding replaceable ink container  12 . In the preferred embodiment, the fluid interconnect  36  extends into the reservoir  34  to compress the capillary member, thereby forming a region of increased capillarity adjacent the fluid interconnect  36 . This region of increased capillarity tends to draw ink toward the fluid interconnect  36 , thereby allowing ink to flow through the fluid interconnect  36  to the printhead  16 .  
         [0030]    The replaceable ink container  12  further includes a guide feature  40 , an engagement feature  42 , a handle  44  and a latch feature  30  that allow the ink container  12  to be inserted into the receiving station  14  to achieve reliable fluid interconnection with the printhead  16  as well as form reliable electrical interconnection between the replaceable ink container  12  and the scanning carriage  20 .  
         [0031]    The receiving station  14  includes a guide rail  46 , an engagement feature  48  and a latch engagement feature  50 . The guide rail  46  cooperates with the guide rail engagement feature  40  and the replaceable ink container  12  to guide the ink container  12  into the receiving station  14 . Once the replaceable ink container  12  is fully inserted into the receiving station  14 , the engagement feature  42  associated with the replaceable ink container engages the engagement feature  48  associated with the receiving station  14 , securing a front end or a leading end of the replaceable ink container  12  to the receiving station  14 . The ink container  12  is then pressed downward to compress a spring biasing member  52  associated with the receiving station  14  until a latch engagement feature  50  associated with the receiving station  14  engages a hook feature  54  associated with the latch member  30  to secure a back end or trailing end of the ink container  12  to the receiving station  14 . It is the cooperation of the features on the ink container  12  with the features associated with the receiving station  14  that allow proper insertion and functional interfacing between the replaceable ink container  12  and the receiving station  14 .  
         [0032]    [0032]FIG. 5 depicts an exemplary embodiment of an ink jet printing system  10 ′ modified to accommodate the off-axis supply adaptor of the present invention. As shown in FIG. 5, an off-axis Ink supply  102  is plumbed via a flexible tube  110  to the fluidic interconnect between the scanning print head and the original on axis ink supply. A relief loop  112  in the tube allows the printer scanning carriage portion  20  to freely scan across the media  22 . The remote supply  102  may be attached to the side of the printer housing at the appropriate height relative to the print head to provide appropriate system backpressure and fluid flow function, or may be otherwise mounted in any convenient manner. Furthermore, the supply pressure may be controlled in some other manner to allow convenient mounting of the remote supply, such as by pressurizing the supply, as is well-known in the art (not shown). The supply  102  is preferably made of a clear material to provide visual ink level feedback to the operator, or the supply could incorporate any of a number of common fluid level indicators known in the art. The flexible tube  110  (excepting the relief loop) may be affixed to the printer in any convenient manner, such as adhesives or plastic ties.  
         [0033]    For printing systems that require electronic communication between the printer and the electrical storage device  80  (not shown in FIG. 5) on the on-axis ink supply, either an old (modified) ink supply  12 ′, as discussed below, or an electronic device emulating the function of an electrical storage device can be used to preserve the required electrical interface. While FIG. 5 illustrates a printer system modified to accept an off-axis supply of one ink color, such as black; the concept of the present invention may be extended to multiple off-axis supplies.  
         [0034]    [0034]FIG. 6 is a simplified exploded view of the off-axis supply adaptor of the present invention, showing the modified ink delivery path. The off-axis ink supply  102  of the exemplary embodiment comprises a clear plastic container  104  with a removable top lid  106  to allow for easy refilling, and is connected to the flexible tube  110  by a cap  108 .  
         [0035]    As shown in FIG. 6, modified ink supply  12 ′ comprises a standard ink supply with both the top cover and the internal capillary material removed, thus providing access to the fluid port  37  of the ink container. The electrical storage device  80  (not shown in FIG. 6) of the modified ink supply is discussed with respect to FIG. 7, below. In the exemplary embodiment, the flexible tube  110  engages the fluid interconnect  36  of the printer, which extends through the fluid port  37  when the modified ink supply is installed in the printer. The off-axis ink supply  102  is thus in fluid communication with printhead  16 . In the exemplary embodiment, the flexible tube is first “primed” with ink prior to attachment to the fluid interconnect  36  to avoid ink starvation of the printhead.  
         [0036]    [0036]FIG. 7 is a simplified schematic representation further illustrating the modified ink jet printing system  10  of FIG. 6, with a single printhead  16  connected to a single ink container  12 . The printer portion  18  includes the inkjet printhead  16  and a controller  29 . Modified ink container  12 ′ provides electrical and fluidic coupling with the printer portion  18  as discussed with respect to FIG. 2, above. The electrical coupling allows information to be passed between the electrical storage device  80  on the modified ink container  12 ′ and the printer portion  18 . The exchange of information between the modified ink container  12 ′ and the printer portion  18  provides compatibility with the printer by implementing or emulating those functions discussed with respect to the unmodified printer system of FIG. 2, above. The electrical storage device may also be programmed to optimize printing with the off-axis adaptor, with data indicating any special characteristics of the off-axis supply, such as the ink capacity of the supply.  
         [0037]    [0037]FIG. 8 is a simplified exploded view illustrating an alternate embodiment of the supply adaptor of the present invention, in which a large free-ink supply is carriage-mounted. The carriage-mounted ink supply  202  of the alternate embodiment comprises a clear plastic container  204  with a removable top lid  206  to allow for easy refilling. A short resilient member  210 , which may be a piece of flexible tubing, allows the supply to engage the fluid interconnect  36  of the printer which extends through the fluid port  37  when the modified ink supply is installed in the printer. As in the above-described exemplary embodiment, the modified ink supply  12 ′ comprises a standard ink supply with both the top cover and the internal capillary material removed. In use, the carriage-mounted supply is installed in the printer and then filled with ink. The operator can visually monitor the ink level in the supply, and refill it when necessary.  
         [0038]    While described above with respect to a single off-axis ink supply, the present invention may be extended to multiple off-axis supplies, such as supplies for each primary color in a color printing system. In a color printing system, the present invention provides the additional benefit of lower ink wastage, since printer users who tend to predominantly print specific colors can replenished the colors separately, as opposed to the replacing a common “ganged” on-axis color ink supply.  
         [0039]    The modified printing system of the present invention provides an option to printer users who want to purchase a lower price on-axis ink supply printer and maintain the flexibility to use it in high usage applications with a convenient intervention rate and lower overall cost per page operating costs. This present invention also provides visual feedback to the user about ink level therefore protecting against premature print head degradation (from air ingestion).  
         [0040]    Although described with respect to a particular exemplary embodiment, the present invention is applicable to other printer systems having on-axis ink supplies separately replaceable from the printheads.  
         [0041]    The above is a detailed description of particular embodiments of the invention. It is recognized that departures from the disclosed embodiments may be within the scope of this invention and that obvious modifications will occur to a person skilled in the art. It is the intent of the applicant that the invention include alternative implementations known in the art that perform the same functions as those disclosed. This specification should not be construed to unduly narrow the full scope of protection to which the invention is entitled.