Abstract:
In one embodiment, a fluid ejector assembly includes: an inlet structure having an opening therein through which fluid may enter the assembly, the inlet structure having a rim generally defining an outer perimeter of the inlet structure around the opening; a conduit through which fluid may pass from the opening in the inlet structure to an ejector structure; and a filter supported on the inlet structure and spanning the opening such that fluid passing through the opening in the inlet structure to the conduit passes through the filter, a peripheral edge of the filter surrounded by the rim of the inlet structure and the peripheral edge of the filter encapsulated by the inlet structure.

Description:
This application claims the benefit of U.S. Provisional patent application Ser. No. 61/052,348 filed on 12 May 2008, which is hereby incorporated 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. The inlet to the printhead assembly is commonly referred to as an inlet “tower” because it usually extends out from the surrounding structure. Poor contact between the wick at the outlet of the ink container and the filter at the inlet tower may impede proper ink flow. Air leaking into the printhead assembly at this fluid interconnection may also impede ink flow. Thus, it is desirable to protect the filter from damage that can occur during repeated installations and removals of the ink containers. 
     The inlet tower structure for a printhead assembly is usually assembled by staking a stainless steel mesh filter onto the top of the tower. The exposed edges of the filter, which may contain loose fibers where the filter is punched or otherwise cut from a sheet of fabric mesh, is particularly susceptible to damage. To prevent the edge of the filter from coming into direct contact with the outlet/snout on the ink container, and thus help prevent damage to the filter, the peripheral edge of the filter may be recessed into the tower so that the rim of the tower is significantly higher than the edge of the filter. It was thought that the higher tower rim would protect the filter from damaging contact with the container outlet. However, it has been observed that this recessed filter design cannot be relied on to protect the filter from damage while still allowing a robust fluid interconnection. If the rim is too high with respect to the filter, then the rim may prevent the wick in the container outlet from making full contact with the filter. If the rim is too low, then the edge of the filter may be exposed to the container outlet, creating a risk of damage during installation and removal of the container. 
    
    
     
       DRAWINGS 
         FIG. 1  is a block diagram illustrating one embodiment of an inkjet printer. 
         FIGS. 2 and 3  are perspective views of an 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 illustrating a fluid interconnection between an ink container and the printhead assembly according to an embodiment of the disclosure. 
         FIGS. 5 and 6  are plan and section views, respectively, illustrating the placement of a filter on an inlet structure for a printhead assembly before the filter is secured to the inlet structure. 
         FIGS. 7-10  are section views illustrating a method for securing the filter to the inlet structure according to an embodiment of the disclosure. 
         FIG. 8  is a detail view illustrating of a portion of the inlet structure after a first operation shown in  FIG. 7  in which the edge of the filter is staked to the inlet structure. 
         FIG. 10  is a detail view illustrating of a portion of the inlet structure after a second operation shown in  FIG. 9  in which the edge of the filter is encapsulated in the rim of the inlet structure. 
         FIGS. 11 and 12  are section views illustrating another embodiment of a second operation for encapsulating the rim of the filter. 
         FIGS. 13 and 14  are section views illustrating another method for securing the filter to the inlet structure according to an embodiment of the disclosure in which the filter is secured and the edge encapsulated in a single operation. 
     
    
    
     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 filter ink flow interface throughout repeated installations and removals of the ink container. 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  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 . Referring to  FIG. 4 , fluid interconnection  52  includes a wick  54  in container outlet structure  68  and a filter  56  at printhead assembly inlet structure  66 . 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 . A downstream surface  62  of outlet wick  54  and filter  56  are in contact with one another when container  16  is installed in printhead assembly  14  as shown in  FIG. 4 . An ink channel  64  downstream from filter  56  carries ink to printhead  48  (not shown). Inlet structure  66  is sometimes referred to as an inlet “tower”  66  because it usually extends out from the surrounding structure. Container outlet structure  68  fits around inlet tower  66  and seals against an elastomeric gasket or other suitable seal  70  to help prevent air from entering fluid interconnection  52 . 
       FIGS. 5 and 6  are plan and section views, respectively, illustrating the placement of a filter  56  on an inlet tower  66  before the filter  56  is secured to tower  66 . (Filter  56  in the plan view of  FIG. 5  is depicted with stippling and the underlying structure shown with solid lines for clarity.)  FIGS. 7-10  are section views illustrating a new method for securing filter  56  to tower  66 , according to one embodiment of the disclosure. Referring first to  FIGS. 5 and 6 , a filter  56  is placed over the exposed, top end  72  of tower  66 , covering an opening  74  in tower  66  such that ink passing through opening  74  to ink channel  64  ( FIG. 4 ) must first pass through filter  56 . Top end  72  of tower  66  includes a series of three protrusions  76 , sometimes referred to as dome retention posts, positioned around opening  74  to support the central portion of filter  56 . Top end  72  also includes a ridge  78  inside a peripheral rim  80 . 
     Referring now to  FIGS. 7 and 8 , a heated die or other suitable staking tool  82  stakes an outer peripheral edge  84  of filter  56  to tower top end  72  along ridge  78 . Staking die  82  is shown in contact with filter  56  in  FIG. 7  and withdrawn slightly from filter  56  in  FIG. 8 . The staking operation illustrated in  FIGS. 7 and 8  is a conventional operation commonly used to attach a filter to an inlet tower in an inkjet print cartridge or an inkjet printhead assembly. A heated die or an ultrasonic welding horn are two staking tools often used to attach a filter  56 . In either case, the staking tool  82  softens the plastic tower at ridge  78 , sometimes referred to as an energy director, so that the filter mesh is pressed into the softened plastic, thus “staking” the filter in place on tower  66 . Staking filter  56  in this manner, however, leaves filter edge  84  exposed and subject to damage by container outlet structure  68  and/or wick  54  ( FIG. 4 ) when a container  16  ( FIG. 4 ) is installed into and removed from printhead assembly  14  ( FIG. 4 ). 
     Thus, a second operation, shown in  FIGS. 9 and 10 , is performed to encapsulate filter edge  84  and protect it from damage. Referring now to  FIGS. 9 and 10 , a heated die or other suitable shaping tool  86  contours tower rim  80  to encapsulate outer peripheral edge  84  of filter  56 , as best seen by comparing  FIGS. 8 and 10 . Shaping die  86  is shown in contact with filter  56  in  FIG. 9  and withdrawn slightly from filter  56  in  FIG. 10 . In the embodiment shown in  FIGS. 9-10 , as best seen in  FIG. 10 , a face  88  of shaping die  86  extends inward past filter edge  84  at a right angle, sharp corner to a projecting side  90  that extends down along the top end  72  of tower  66  as die  86  is brought into contact with tower rim  80 . A heated die or an ultrasonic welding horn, for example, are tools that may be used to encapsulate filter edge  84 . In either case, the tool  86  softens the plastic tower rim  80  so that the softened plastic flows into and encapsulates filter edge  84 . If desirable, die  86  may be configured to push a small portion of tower rim  80  down along projecting side  90  to form a barb  92  around the outer rim of tower top end  72 . Barb  90  may be used to help retain seal  70  ( FIG. 4 ) in place around tower  66 . 
     In an alternative embodiment of the second operation, shown in  FIGS. 11 and 12 , die face  88  extends inward at an obtuse angle, rounded corner to projecting side  90 . Also, die face  88  in  FIGS. 11 and 12  is slightly wider so that it slides along the outside of tower top end  72  to not form a barb. 
       FIGS. 13 and 14  are section views illustrating another method for securing filter  56  to tower  66  in which the filter is secured in a single operation. Referring to  FIGS. 13 and 14 , the face  94  of a heated die or other suitable tool  96  is configured to simultaneously stake filter edge  84  to tower top end  72  along ridge  78  and contour tower rim  80  to encapsulate edge  84  within rim  80 . After filter  56  is placed on tower  66  as shown in  FIG. 6  and die  96  is pressed onto tower top end  72 , a staking part  98  of die face  94  stakes filter edge  84  to tower top end  72  (as described above with regard to  FIGS. 7 and 8 ) while an encapsulating part  100  contours rim  80  in to encapsulate filter edge  84 . Upon release of die  96 , as shown in  FIG. 14 , filter edge  84  is staked to tower top end  72  along ridge  78  and encapsulated with the plastic tower material pushed in from rim  80 . Simultaneously staking and encapsulating helps prevent the formation of gaps, pockets, recesses or the like at filter edge  84  during encapsulation because the staking part  98  of die face  94  is pressed into and holds filter  56  against tower top end  72  simultaneously with encapsulating edge  84 . A similar advantage may be gained in the dual operation method described above with reference to  FIGS. 9-12  by configuring the shaping die to press down on filter  56  at the same time material from tower rim  80  is pushed in to encapsulate filter edge  84 . 
     Die faces  88  and  94  shown in  FIGS. 9-14  are just three examples of suitable die face configurations. Die face configurations may be varied, for example, according to the pre-formed/beginning structure of tower top end  72  and the desired post-formed height and shape of tower rim  80 . The pre-formed/beginning configuration of tower top end  72  shown in  FIG. 6  is just one possible starting configuration. The particular tower configuration shown in  FIG. 6 , which represents a conventional configuration already in use, is depicted to illustrate that embodiments of the new methods may be used with a conventional tower structure. In both method embodiments described above, the plastic of tower rim  80  is shaped down and inward to fill any gaps between filter edge  84  and rim  80 . The post-formed rim  80  may have a lower profile, as shown, to be more in line with filter edge  84 . The tower geometry, including the height, thickness and shape of tower rim  80 , may be optimized for the diameter and thickness of filter  56  to help ensure an adequate volume of plastic is available to flow into and around filter edge  84 . 
     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.