Abstract:
In one embodiment, a fluid interconnection between a fluid container and a fluid ejector assembly includes: a first wick at an outlet from the container, the first wick having an upstream surface and a downstream surface; a second wick at an inlet to the ejector assembly, the second wick having an upstream surface and a downstream surface, the upstream surface in direct contact with the downstream surface of the first wick across substantially the entire area of the upstream surface of the second wick; and a filter in direct contact with the downstream surface of the second wick.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Pursuant to 35 U.S.C. §119(a) and 365(b), the present application claims priority from PCT Application No. PCT/US2008/059545 entitled, “Fluid Interconnection” filed on Apr. 7, 2008, the disclosure of which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     Inkjet printers typically utilize a printhead that includes an array of orifices (also called nozzles) through which ink is ejected on to paper or other print media. One or more printheads may be mounted on a movable carriage that traverses back and forth across the width of the paper feeding through the printer, or the printhead(s) may remain stationary during printing operations, as in a page width array of printheads. A printhead may be an integral part of an ink cartridge or part of a discrete assembly to which ink is supplied from a separate, often detachable ink container. For printhead assemblies that utilize detachable ink containers, it is important that the operative fluid connection between the outlet of the ink container and the inlet to the printhead assembly, commonly referred to as a fluid interconnection or “FI”, provide reliable ink flow from the container to the printhead assembly. 
     Ink is drawn from the ink container through a filter on the inlet to the printhead assembly. Poor contact between the capillary material at the outlet of the ink container and the filter at the inlet to the printhead assembly in a conventional fluid interconnection may impede proper ink flow. Air leaking into the printhead assembly at this fluid interconnection may also impede ink flow. Thus, it is desirable that the fluid interconnection provide adequate contact in an airtight connection throughout repeated installations and removals of the ink container. The fluid inlet to the printhead assembly should also protect against losing backpressure and ink prime in the printhead assembly when an ink container is not installed, for example when the ink container is being changed. 
    
    
     
       DRAWINGS 
         FIG. 1  is a block diagram illustrating an inkjet printer. 
         FIGS. 2 and 3  are perspective views of one embodiment of a carriage and printhead assembly, such as might be used in the printer of  FIG. 1 , with the ink containers exploded out from the carriage to show the inlets to the printhead assembly ( FIG. 2 ) and the outlets from the ink containers ( FIG. 3 ). 
         FIG. 4  is an elevation section view showing one embodiment of a fluid interconnection between an ink container and the printhead assembly. 
         FIG. 5  is a detail exploded section view of the fluid interconnection shown in  FIG. 4 . 
     
    
    
     DESCRIPTION 
     Embodiments of the disclosure were developed in an effort to improve the fluid interconnection between a printhead assembly and a detachable/replaceable ink container—to construct a fluid interconnection providing a robust, reliable ink flow interface throughout repeated installations and removals of the ink container while protecting against the loss of backpressure and ink prime in the printhead assembly when an ink container is removed and the printhead assembly inlet is exposed to the atmosphere. Embodiments will be described, therefore, with reference to an inkjet printhead assembly that holds detachable/replaceable ink containers. Embodiments of the disclosure, however, are not limited to such implementations. Embodiments of the disclosure, for example, might also be implemented in other types of ink or fluid dispensing components. The example embodiments shown in the Figures and described below, therefore, illustrate but do not limit the scope of the disclosure. 
       FIG. 1  is a block diagram illustrating an inkjet printer  10  in which embodiments of the disclosure may be implemented. Referring to  FIG. 1 , printer  10  includes a carriage  12  carrying a printhead assembly  14  and detachable ink containers  16 ,  18 ,  20 ,  22 , and  24 . Inkjet printer  10  and printhead assembly  14  represent more generally a fluid-jet precision dispensing device and fluid ejector assembly for precisely dispensing a fluid, such as ink, as described in more detail below. Printhead assembly  14  includes a printhead (not shown) through which ink from one or more containers  16 - 24  is ejected. For example, printhead assembly  14  may include two printheads—one for a series of color containers  16 - 22  and one for a black ink container  24 . An inkjet printhead is typically a small electromechanical assembly that contains an array of miniature thermal, piezoelectric or other devices that are energized or activated to eject small droplets of ink out of an associated array of orifices. A typical thermal inkjet printhead, for example, includes a orifice plate arrayed with ink ejection orifices and firing resistors formed on an integrated circuit chip. 
     A print media transport mechanism  26  advances print media  28  lengthwise past carriage  12  and printhead assembly  14 . For a stationary carriage  12 , media transport  26  may advance media  28  continuously past carriage  12 . For a movable, scanning carriage  12 , media transport  26  may advance media  28  incrementally past carriage  12 , stopping as each swath is printed and then advancing media  28  for printing the next swath. 
     An electronic controller  30  is operatively connected to a moveable, scanning carriage  12 , printhead assembly  14  and media transport  26 . Controller  30  communicates with external devices through an input/output device  32 , including receiving print data for inkjet imaging. The presence of an input/output device  32 , however, does not preclude the operation of printer  10  as a stand alone unit. Controller  30  controls the movement of carriage  12  and media transport  26 . Controller  30  is electrically connected to each printhead in printhead assembly  14  to selectively energize the firing resistors, for example, to eject ink drops on to media  28 . By coordinating the relative position of carriage  12  with media  28  and the ejection of ink drops, controller  30  produces the desired image on media  28 . 
     While this Description is at least substantially presented herein to inkjet-printing devices that eject ink onto media, those of ordinary skill within the art can appreciate that embodiments of the present disclosure are more generally not so limited. In general, embodiments of the present disclosure pertain to any type of fluid-jet precision dispensing device or ejector assembly for dispensing a substantially liquid fluid. The fluid-jet precision dispensing device precisely prints or dispenses a substantially liquid fluid in that the latter is not substantially or primarily composed of gases such as air. Examples of such substantially liquid fluids include inks in the case of inkjet printing devices. Other examples of substantially liquid fluids include drugs, cellular products, organisms, chemicals, fuel, and so on, which are not substantially or primarily composed of gases such as air and other types of gases. Therefore, while the Description is described in relation to an inkjet printer and inkjet printhead assembly for ejecting ink onto media, embodiments of the present disclosure more generally pertain to any type of fluid-jet precision dispensing device or fluid ejector structure for dispensing a substantially liquid fluid. 
       FIGS. 2 and 3  are perspective views of one embodiment of a carriage  12  and printhead assembly  14  in printer  10 . Ink containers  16 - 24  are exploded out from carriage  12  to show ink inlets  34  to printhead assembly  14  ( FIG. 2 ) and ink outlets  36  from ink containers  16 - 24  ( FIG. 3 ). Referring to  FIG. 2 , printhead assembly  14  includes an ink inlet  34  positioned at each bay  38 ,  40 ,  42 ,  44 , and  46  for a corresponding ink container  16 - 24 . Printhead assembly  14  and carriage  12  may be integrated together as a single part or printhead assembly  14  may be detachable from carriage  12 . For a detachable printhead assembly  14 , container bays  38 - 46  may extend out into carriage  12  as necessary or desirable to properly receive and hold containers  16 - 24 . 
     Referring to  FIG. 3 , in the embodiment shown, printhead assembly  14  includes two printheads  48  and  50 . Ink from color ink containers  16 - 22 , for example, is ejected from printhead  48  and ink from a black container  24  is ejected from printhead  50 . Each ink container  16 - 24  includes an ink outlet  36  through which ink may flow from container  16 - 24  through an inlet  34  ( FIG. 2 ) to a corresponding printhead  48  or  50  in printhead assembly  14 . 
       FIG. 4  is an elevation section view showing one embodiment of a fluid interconnection  52  between an ink container  16  and printhead assembly  14 .  FIG. 5  is a detail section view of fluid interconnection  52 . Printhead assembly inlet  34  and container outlet  36  are shown exploded apart from one another in  FIG. 5  to better illustrate some parts of interconnection  52 . Referring to  FIGS. 4  and  5 , fluid interconnection  52  includes a wick  54  in container outlet  36  and a wick  56  at printhead assembly inlet  34 . An upstream surface  58  of outlet wick  54  contacts foam or other ink holding material  60  in container  16 . Alternatively, where an ink container  16  holds so-called “free ink”, and there is no ink holding material, then upstream surface  58  will be exposed to the free ink in container  16 . The downstream surface  62  of outlet wick  54  and the upstream surface  64  of inlet wick  56  are in contact with one another when container  16  is installed in printhead assembly  14 . The downstream surface  66  of inlet wick  56  contacts a filter  68 . An ink channel  70  downstream from filter  68  carries ink to printhead  48  (not shown). 
     Inlet wick  56  may protrude slightly from the top of an inlet tube  72 , as shown, so that wicks  54  and  56  are compressed together slightly to optimize contact between uniformly wetted surfaces and, accordingly, help provide robust wick-to-wick ink flow. Also, wicks  54  and  56  made from the same materials, or otherwise having substantially the same wicking characteristics, will improve the consistency of the wetted contact surfaces to help improve ink flow. To function more effectively, wicks  54  and  56  should have a higher capillarity than the capillary media  60  in container  16  or, in a free ink container, having a capillarity sufficiently high to remain wetted while exposed when changing the ink container. The diameter (or other cross sectional dimension if not round) of downstream surface  62  of outlet wick  54  should be larger than that of upstream surface  64  of inlet wick  56  to reduce the risk of misalignment that might leave inlet wick  56  exposed to the atmosphere, thus reducing the risk of ingesting air into printhead assembly  14  through inlet wick  56 . 
     Inlet tube  72  is sometimes referred to as an inlet “tower”  72  because it will usually extends out from the surrounding structure. Container outlet structure  74  fits around inlet tower  72  and seals against an elastomeric gasket or other suitable seal  76  to help prevent air from entering fluid interconnection  52 . In the embodiment shown, inlet wick  56  and filter  68  are seated in a recess  78  along the inside perimeter of tower  72 . Inlet wick  56  should be compressed slightly within tower  72  (i.e., an interference fit) and extend beyond the edges of filter  68 , as shown, to help ensure that no outside air reaches filter  68  even when an ink container  16  is being changed and inlet wick  56  is temporarily exposed to the atmosphere—venting to the atmosphere through tower  72  may cause loss of backpressure in and depriming of printhead  48 . In the embodiment shown, filter  68  is staked into position in tower recess  78  using a stake ring  80 . Although filter  68  may be affixed to tower  72  using any suitable technique or structural configuration, the resulting structure should allow inlet wick  56  to overlap the edge(s) of filter  68  by at least 1 mm to help protect against unwanted venting. 
     The wick-to-wick interface of fluid interconnection  52  helps prevent “installation drool” in which ink drools from the printhead orifices as air is pushed into the printhead when an ink container is installed on to the printhead assembly tower. In addition, once the inlet wicks  56  are wetted and the printheads  48  and  50  primed with ink, inlet wick  56  will effectively seal each inlet  34  from the atmosphere during container changes, maintaining proper backpressure and thus allowing printheads  48  and  50  to stay primed and not drool. Unlike some conventional fluid interconnects in which the filter sits atop the inlet tower, exposed to the ink container outlet structure, inlet wick  56  in fluid interconnection  52  protects filter  68  from damage by container outlet structure  74  when a container is installed in and removed from printhead assembly  14 . 
     As noted at the beginning of this Description, the example embodiments shown in the figures and described above illustrate but do not limit the disclosure. Other forms, details, and embodiments may be made and implemented. Therefore, the foregoing description should not be construed to limit the scope of the disclosure, which is defined in the following claims.