Patent Abstract:
A seal for an ink-discharge port on a printer ink cartridge, according to various embodiments of the present invention, is disclosed. The seal has a surface containing channels that oppose a direction in which the port is configured to discharge ink from the ink cartridge. Such channels facilitate the retention of ink by the seal during removal of the seal, thereby reducing the likelihood of ink spillage during such removal.

Full Description:
FIELD OF THE INVENTION 
   This invention pertains to a seal for a fluid-discharge port on a fluid reservoir. The seal is configured to prevent loss of fluid from the fluid reservoir through the port, for example, during shipping or storage. In particular, this invention pertains to aspects of a surface of the seal that faces the port opening and opposes a direction in which the port is configured to discharge fluid. Such aspects improve, among other things, the retention of fluid on the surface of the seal during removal of the seal, thereby reducing spillage or splattering of fluid during removal of the seal. 
   BACKGROUND OF THE INVENTION 
   Fluid reservoirs, such as ink cartridges for ink jet printers, commonly have one or more fluid-discharge ports with an opening through which fluid is delivered during use. In order to prevent loss of fluid, for example by spillage or evaporation during shipping or storage, it is common to provide a seal for the port or each of the ports. When the seal is removed so that the fluid reservoir can be used, it is important not to spill or splatter droplets of the fluid. 
   Fluid-ejection printing devices, such as ink jet printers, commonly have at least one fluid reservoir (or ink cartridge) and a printhead chassis that supports the ink cartridge. The ink cartridge may contain one or more fluid chambers that provide fluid to a printhead. If the ink cartridge has more than one ink chamber, each such chamber often retains fluid of a different color or function for multi-color printing. On the other hand, if the ink cartridge has only a single ink chamber, typically such chamber is used to retain a single fluid, such as black ink for black-and-white printing. 
   The printhead die containing the nozzles is typically connected directly or indirectly to the chassis. In order to form an image, the printhead die, along with the chassis and the ink cartridge, generally are moved in a lateral direction across a width of a substrate, such as paper, as fluid is ejected from the printhead. After the printhead forms a row-portion of the image along the width of the substrate, the substrate is advanced in a direction perpendicular to the lateral direction along a length of the substrate, so that the printhead can form a subsequent row-portion of the image. This process of advancing the substrate for each row-portion is repeated until a next substrate is needed or the image is completed. 
   When an ink chamber in the ink cartridge runs out of ink, a user is charged with the responsibility of removing the empty ink cartridge from the chassis and replacing it with a full ink cartridge. The task of replacing an ink cartridge must be simple and clean. Ink should not be allowed to stain the user&#39;s hands or clothes, and it also must not be allowed to drip into areas of the printer where it might cause damage. 
   When a new ink cartridge is shipped, a shipping seal is provided to seal the fluid discharge port(s). The shipping seal helps to prevent ink evaporation during long-term storage, as well as ink spillage due to air pressure changes that occur, for example, during air travel. However, subsequent to shipping, conventional seals have been found to allow fluid to splatter during a user&#39;s removal of the seal, thereby possibly causing staining or damage. Accordingly, a need in the art exists for a solution that mitigates the risk of fluid splatter during removal of a shipping seal from an ink cartridge. 
   SUMMARY 
   The above-described problem is addressed and a technical solution is achieved in the art by a seal for a fluid-discharge port on a fluid reservoir, according to various embodiments of the present invention. The seal has a surface containing channels that oppose a direction in which the port is configured to discharge fluid. Such channels facilitate the retention of fluid by the seal during removal of the seal, thereby reducing the likelihood of fluid spillage. 
   At least one of the channels may have a smallest dimension, such as a width of approximately 0.05 mm to 0.25 mm. At least one of the channels may have a rounded or substantially rounded bottom. And, at least one of the channels may have a pointed or substantially pointed bottom. 
   According to various embodiments of the present invention, at least some of the channels may intersect at right angles, at substantially right angles, or obliquely. According to various embodiments of the present invention, the channels may be formed between protrusions. The protrusions may comprise a sloped side wall. In addition, the protrusions may include sloped side walls that form a point, substantially a point, an edge, or substantially an edge. In this case, the smallest dimension of the point or edge may be approximately 0.05 mm or 0.25 mm. According to an embodiment of the present invention, the protrusions may comprise rounded or substantially rounded tops. 
   According to various embodiments of the present invention, the protrusions may have approximately a first height and the seal may further include a containment wall around or substantially around a periphery of the seal, such that the containment wall has a height approximately greater than or equal to the first height. A width of a top surface of the containment wall may be approximately between 1 mm and 2 mm. The containment wall may have an outside edge that is stepped, and the outside edge may include a plurality of steps. 
   According to various embodiments of the present invention, the seal may include a storage area configured to retain excess fluid from the reservoir. In this case, the surface of the seal may include openings communicatively connected to the storage area. The storage area may be located beneath the surface. 
   According to various embodiments of the present invention, the seal may be formed of a compressible material, such as EPDM rubber or a thermoplastic elastomer, known in the art. The seal may be a hydrophilic material. 
   According to various embodiments of the present invention, a printer ink cartridge is provided, the printer ink cartridge including a fluid reservoir, a fluid-discharge port, a porous media, and a seal according to one of the various embodiments of the present invention highlighted above. The porous media is positioned in the port. According to these embodiments, the surface of the seal includes (a) protrusions between which are the channels, and (b) a containment wall around or substantially around a periphery of the seal. Also according to these embodiments, a space may exist between the protrusions and the porous media, and a space may exist between the containment wall and the porous media. 
   In addition to the embodiments described above, further embodiments will become apparent by reference to the drawings and by study of the following detailed description. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be more readily understood from the detailed description of exemplary embodiments presented below considered in conjunction with the attached drawings, of which: 
       FIG. 1  illustrates a printhead chassis for retaining one or more print cartridges; 
       FIG. 2  shows an isometric view of a multi-chamber ink cartridge; 
       FIG. 3  shows an exploded view of a multi-chamber ink cartridge; 
       FIG. 4  shows a bottom view of a multi-chamber ink cartridge; 
       FIG. 5  shows a side view of a fluid reservoir with a sealing member held in place against the port opening by a seal retainer; 
       FIG. 6  shows an isometric view of a sealing member, according to an embodiment of the present invention; 
       FIG. 7  shows close-up isometric view of a portion of a sealing member, according to an embodiment of the present invention; 
       FIG. 8  shows a top view of a portion of a sealing member, according to an embodiment of the present invention; 
       FIG. 9  shows a close-up isometric view of an array of protrusions and channels on the surface of a sealing member, according to an embodiment of the present invention; 
       FIG. 10  shows a close-up isometric view of protrusions having a top edge which may be sharp or flat or rounded, according to embodiments of the present invention; 
       FIG. 11  shows a close-up isometric view of an array of protrusions and channels with rounded bottoms on the surface of a sealing member, according to an embodiment of the present invention; and 
       FIG. 12  shows a close-up isometric view of an array of protrusions and channels with openings in the surface of a sealing member, according to an embodiment of the present invention. 
   

   It is to be understood that the attached drawings are for purposes of illustrating the concepts of the invention and may not be to scale. 
   DETAILED DESCRIPTION 
   Embodiments of the present invention provide one or more channels in the surface of a sealing member which faces the opening of a port of a fluid reservoir. Although particular examples of a fluid reservoir often are provided in the context of an ink jet ink cartridge, it is to be understood that the invention is applicable more generally to sealing members for ports of fluid reservoirs. 
     FIG. 1  illustrates a printhead chassis  10  having a region  12  for a multi-chamber ink cartridge, and also a region  14  for a single-chamber ink cartridge. Regions  12  and  14  are separated by one or more partitions  16  which also serve as guides for inserting the ink cartridges into the printhead chassis. In region  12 , several fluid reception ports  18  are shown which make connection with the corresponding fluid discharge ports of a multi-chamber ink cartridge, when the ink cartridge is inserted. Region  14  also has a single fluid reception port (hidden by partition  16 ) corresponding to the fluid discharge port of a single-chamber ink cartridge. Not shown in the view of  FIG. 1  is the printhead die and its nozzles. Typically, the printhead die would be located underneath the printhead chassis, in a region below the fluid reception ports  18 . 
     FIG. 2  shows an isometric view of a multi-chamber ink cartridge  20  which may be inserted into region  12  of printhead chassis  10 . The particular ink cartridge  20  shown in  FIG. 2  has five chambers within reservoir body  22 , each chamber of which leads to a fluid discharge port  24 . The five chambers serve as reservoirs intended to hold five fluid sources. The five sources may be, for example, cyan ink, magenta ink, yellow ink, photo black ink, and a protective fluid. Alternatively, they may be cyan ink, light cyan ink, magenta ink, light magenta ink, and yellow ink; or they may be a different combination of fluids. Ink cartridge  20  is shown as having a lid  30  in the example shown in  FIG. 2 . Lid  30  may be affixed to reservoir body  22 . Together, lid  30  and reservoir body  22  make up the ink cartridge body. Typically the lid  30  and the reservoir body  22  are each formed by injection molding. 
     FIG. 3  shows an exploded view of multi-chamber ink cartridge  20  as well as seal assembly  50 . For the particular example shown in  FIG. 3 , pressure regulation for the ink cartridge is provided by capillary media  42  and wick  44 , as is described in greater detail in the co-filed application titled “Ink Jet Ink Cartridge with Vented Wick”, by Pearson, et al., application Ser. No. 11/679,925, filed Feb. 28, 2007. Both the capillary media and the wick are typically formed of porous media, such as foam, or felt, or fiber bundles. However, the wick and capillary media are not essential features for this invention. Lid  30  is affixed to reservoir body  22  by ultrasonic welding or other means of adhering the lid to the reservoir body  22 . One or more labels  36  may optionally be applied to the top surface of the lid  30 . Ink or fluids of various types are typically held in the various chambers of the ink cartridge. 
     FIG. 4  shows a bottom view of multi-chamber ink cartridge  20  with the bottom surface  45  of each wick  44  visible within each port  24 . Note that the bottom surface  45  of wick  44  is recessed somewhat relative to the outer rim (or bottom surface)  26  of port  24 . 
   Before the ink cartridge  20  is ready to be shipped to the customer, the ports must be sealed in order to prevent leakage or excessive evaporation of volatile ink components. Many different styles of seals are possible to be used. For example, a film may be affixed to the outer rim of each port. For this type of seal, the customer may pull a tab at an end of the film and thereby pull the seal away from each port. A second alternative is a twist-off seal, although this type of seal is more compatible with a cartridge having only a single port. With a row of ports  24  as in multi-chamber ink cartridge  20 , the amount of torque to twist off seals from five adjacent chambers would be excessively difficult for the user to apply. A third alternative is a seal of the type provided by seal assembly  50  shown in  FIG. 3 . Seal assembly  50  includes a compliant seal member  52  which is held in place at the ports  24  by seal retainer  54 . Compliant seal member  52  is typically is formed using an elastomeric material such as EPDM rubber. Seal retainer  54  is typically formed by injection molding. The sealing member may protrude somewhat into the port, but typically there is still an air space between the bottom surface  45  of wick  44  and the sealing member. A fourth alternative is to use the compliant seal member without a seal retainer. In such an alternative, the elastic properties of the seal member material would be used to hold it in place—for example, by having a portion of the seal member material surround the outer rim of the port(s) to hold the seal member in place. 
     FIG. 5  shows a cutaway side view of ink cartridge  20  with seal assembly  50  installed in order to prepare it for shipping and other fluid-retention purposes. Sealing member  52  is shown pressed against port  24  and held in place by seal retainer  54 . In order to remove seal retainer  54 , the user presses on seal retainer lever  56  in a downward direction denoted by arrow  60 . As a result, the sealing member  52  is pulled away from outer rim  26  of fluid discharge port  24  in a direction denoted by arrow  62 . 
   As the sealing member  52  is pulled away from the port, some amount of ink may be located on the surface of the sealing member which had faced the port opening and which opposed a direction in which the port  24  is configured to discharge ink. If the seal is pulled away suddenly, droplets of ink may splatter out and stain the hands of the user or get onto the printer or other objects. This is true whether the seal is a compliant seal such as sealing member  52 , or whether the seal is an adhesively affixed film. This problem, which is addressed by the present invention, is exacerbated for configurations of fluid reservoirs and seals such that transient pressure changes occur when the seal is removed, due to air volume changes between the port and the surface of the seal. Somewhat less susceptible to such pressure changes are the types of seals which may be removed in a twisting motion, since the volume change is very small as the seal is broken. However, as mentioned above, twist-off type seals are not very compatible with multi-chamber ink cartridges having a row of adjacent ports  24 . 
     FIG. 6  shows an isometric view of a sealing member  52  according to an embodiment of this invention. In the example shown in  FIG. 6 , sealing member  52  is configured with five port seals  70  (corresponding to five ports of a five-chamber fluid reservoir). The port seals  70  are joined by and extend from a sealing member base top surface  72 . The port seals may include a containment wall  74  having a flat top surface and/or a stepped edge  76 . Within the region surrounded by containment wall  74  may be a plurality of protrusions  82  which are separated from one another by channels  84  (see also the top view shown in  FIG. 8 ). 
   In a preferred embodiment, the sealing member  52  is formed of a compressible material, such as EPDM rubber or a thermoplastic elastomer. The port seals  70  are configured such that each containment wall  74  fits within the outer rim  26  of the corresponding fluid discharge port  24 . When the sealing member  52  is pressed against the fluid discharge ports  24  (for example by seal retainer  54 ), it is the stepped edge  76  that provides the seal against the inner surface  27  of the outer rim  26 . Although not required, providing a plurality of steps in stepped edge  76  can improve seal reliability. A function of containment wall  74 , protrusions  82  and channels  84  is to retain residues of ink or other fluid which may be on the surface of the port seal  70  when the sealing member  52  is removed from the fluid discharge ports  24 . The channels  84  between the protrusions  82  provide capillary forces, which tend to hold the fluid residue, as well as some amount of storage volume, so that the fluid has less tendency to splatter off the surface of the port seal  70  when the sealing member  52  is removed from the fluid discharge ports  24 . In some applications, for example, when the inks or fluids are water-based, the surface of the sealing member  52  may be made of a hydrophilic material to provide additional holding forces for the fluid residue. 
     FIG. 7  shows a close-up isometric view of a portion of sealing member  52  in order to provide a better view of the containment wall  74 , the protrusions  82 , and the stepped edge  76 . In the embodiment shown in  FIG. 7 , the protrusions  82  are shown as pyramid-shaped, with sloping walls. The height of the protrusions  82  relative to the top surface  72  of the sealing member  52  is h 1 . The height of containment wall  74  relative to the top surface  72  of the sealing member  52  is h 2 . In some embodiments, it is advantageous for fluid retention if the height of containment wall  74  is greater than or equal to the height of protrusions  82 . In other words, h 2 ≧h 1 . Further, in some embodiments, it is advantageous for the interference of the stepped edge  76  against the inner surface  27  of outer rim  26  to be such that neither the protrusions  82  nor the containment wall  74  touch any solid feature with fluid discharge port  24 , such as a wick  44  or capillary media  42 . 
     FIG. 8  shows a top view of a port seal  70  to show the two-dimensional array of protrusions  82  and channels  84 . In the embodiment shown in  FIG. 8 , the protrusions  82  in the two-dimensional array are separated from neighboring protrusions  82  by a series of horizontal channels  83  and vertical channels  85 . In this example, the channels are shown as intersecting at right angles, but they can alternatively intersect obliquely. In fact, channels may be configured in a spiral pattern, for example, and not intersect at all. The primary requirement is that the channels  84  and protrusions  82  have geometries conducive to providing capillary forces to promote the retention of fluid on the surface when the sealing member  52  is removed from the fluid discharge ports  24 . 
   Further geometrical details of shapes and dimensions will be discussed with reference to  FIG. 7-11 . The distance between adjacent channels (pitch p shown in  FIG. 8 ) is typically on the order of 1 mm, but may range, for example, between 0.3 mm and 2 mm. The height h 1  of protrusions  82  is typically on the order of 0.5 mm. The width of the top surface of containment wall  74  ranges between approximately 1 mm and 2 mm. 
     FIG. 9  shows a close-up isometric view of several protrusions  82  and channels  84 . In the embodiment of  FIG. 9  each protrusion  82  consists of four sloping sidewalls  81  which meet at a point  86 . In other words, the protrusions are pyramid shaped. The horizontal channels  83  and the vertical channels  85  are shown in the example of  FIG. 9  to have sharp corners and well defined widths. It is not required that the width of the horizontal channels  83  and the width of the vertical channels  85  be equal to each other. 
     FIG. 10  shows a close-up isometric view of other alternative shapes for protrusions  82 . For example, rather than meeting at point  86 , the sloping sidewalls  81  may meet at an edge or line  87 . In other words, the protrusion  82  can be tent-shaped. Alternately the protrusion  82  may be truncated at the top to provide a flat or rounded surface  88 . A smallest dimension of the top of the protrusion  82  is shown as  89 . Whether the top of the protrusion is a point, an edge, or a flat or rounded surface, a typical smallest dimension of the top of the protrusion  82  ranges from 0.05 mm to 0.25 mm. 
     FIG. 11  shows a close-up isometric view of an alternate shape for channels  84 . In  FIG. 11 , rather than the channels  84  having a flat bottom, they have a rounded bottom  90 . Other non-flat channel options include V-shaped channels. In any case, the smallest dimension, such as a width, of the channels typically ranges from approximately 0.05 mm to 0.25 mm. 
     FIG. 12  shows a close-up isometric view (with a sliced open front edge) of a sealing member  52  having increased storage capacity for fluid residue.  FIG. 12  shows a portion of sealing member  52  in the region of the protrusions  82  and channels  84  for an alternative embodiment of the invention. In this embodiment, openings  92  are provided in the surface  91  of the channels  84 . Openings  92  lead to a storage region  93  within sealing member  52  in which additional fluid may be stored. 
   Although the examples above discuss embodiments in a multi-chamber fluid reservoir  20 , it is to be understood that the same advantages apply to a single chamber fluid reservoir. 
   The various embodiments of this invention are particularly advantageous for, among other things, fluid reservoirs and sealing members such that the sealing member is removed in a fashion that momentarily increases the air volume between the sealing member and the interior of the fluid discharge port, such that a transient reduction of air pressure occurs within the fluid discharge port. Such configurations are particularly susceptible to fluid residue being transferred to the surface of the sealing member, resulting in ink splatters if the surface cannot hold the residue. For example, embodiments of the present invention are particularly advantageous for, among other things, seals which are not removed by twisting them off. 
   It is to be understood that the exemplary embodiments are merely illustrative of the present invention and that many variations of the above-described embodiments can be devised by one skilled in the art without departing from the scope of the invention. It is therefore intended that all such variations be included within the scope of the following claims and their equivalents. 
   
     
       
             
           
             
             
           
         
             
                 
             
             
               PARTS LIST 
             
             
                 
             
           
           
             
                 
             
           
        
         
             
               10 
               Printhead chassis 
             
             
               12 
               Region for multi-chamber cartridge 
             
             
               14 
               Region for single chamber cartridge 
             
             
               16 
               Partition 
             
             
               18 
               Fluid reception port 
             
             
               20 
               Multi-chamber ink cartridge 
             
             
               22 
               Reservoir body 
             
             
               24 
               Fluid discharge port 
             
             
               26 
               Outer rim of fluid discharge port 
             
             
               27 
               Inner surface of outer rim 
             
             
               30 
               Lid 
             
             
               36 
               Label 
             
             
               42 
               Capillary media 
             
             
               44 
               Wick 
             
             
               45 
               Bottom surface of wick 
             
             
               46 
               Wick opening 
             
             
               50 
               Seal assembly 
             
             
               52 
               Seal member 
             
             
               54 
               Seal retainer 
             
             
               56 
               Seal retainer lever 
             
             
               60 
               Direction arrow 
             
             
               62 
               Direction arrow 
             
             
               70 
               Port seal 
             
             
               72 
               Sealing member base 
             
             
               74 
               Containment wall 
             
             
               76 
               Stepped edge 
             
             
               81 
               Sloping sidewalls of protrusions 
             
             
               82 
               Protrusions 
             
             
               83 
               Horizontal channels 
             
             
               84 
               Channels 
             
             
               85 
               Vertical channels 
             
             
               86 
               Point of protrusions 
             
             
               87 
               Edge intersection of protrusions 
             
             
               88 
               Truncated top of protrusion 
             
             
               89 
               Smallest dimension of protrusion 
             
             
               90 
               Rounded bottom of channel 
             
             
               91 
               Surface of channel 
             
             
               92 
               Opening 
             
             
               93 
               Storage region

Technology Classification (CPC): 1