Abstract:
An ink printer cartridge is provided wherein ink is stored in a foam reservoir situated within an ink chamber. The foam reservoir does not substantially fill the interior space of the ink chamber, and in particular does not contact the lid of the cartridge. The foam reservoir is retained in place by means of a clip which abuts the top of the foam reservoir. In an embodiment, the clip may compress the foam. A number of features of clip are disclosed, including particular arrangements for fitting into the cartridge, and adjustments as to height and width.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims the benefit of U.S. Provisional Application No. 60/205693, filed on May 26, 2001 the contents of which are hereby incorporated by reference. 
     
    
     
       BACKGROUND  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to a cartridge useful for storing ink for use with a printer. Most typically, such a printer is an ink-jet printer such as is used in connection with a personal computer, although the present invention is not limited to any particular type of printer.  
           [0004]    2. Description of Related Art  
           [0005]    A common method of storing ink in a printer cartridge for use with an ink printer is to store the ink in a foam reservoir. The ink is extracted from the foam reservoir through a through-hole (nozzle port) in the cartridge so that it may ultimately be applied to the paper or other print medium.  
           [0006]    In some cases, the extraction of ink from the foam reservoir is improved if the foam reservoir is compressed. In U.S. Pat. No. 5,158,377 of Suzuki et al. (which is merely one of a number of related patents of Suzuki et al., such as U.S. Pat. No. 4,969,759), it is disclosed to store a porous ink member in a space (ink tank) such that the ink member is compressed by the cover defining the top of the space. In such a configuration, the porous ink member substantially fills the ink supply-tank.  
         SUMMARY  
         [0007]    The present invention provides a printer cartridge wherein the ink is stored in a foam reservoir situated within an ink chamber. The foam reservoir does not substantially fill the interior space of the ink chamber, and in particular does not contact the lid of the cartridge. In one embodiment, a retention clip compresses the foam into a smaller area than it would occupy if the retention clip was not present. In an alternate embodiment, the clip does not compress the foam, but instead serves to hold the foam in place.  
           [0008]    A number of features of the retention clip are disclosed, including particular arrangements for fitting into the cartridge, and adjustments as to height and width. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    [0009]FIG. 1 is an exploded perspective view of an embodiment of the present invention.  
         [0010]    [0010]FIG. 2 is an exploded side elevation view of an embodiment of the present invention.  
         [0011]    [0011]FIG. 3 is a top view of an embodiment of the present invention.  
         [0012]    [0012]FIG. 4 is a section view of an embodiment of the present invention taken along the line A-A of FIG. 3.  
         [0013]    [0013]FIG. 4A shows an alternate embodiment, otherwise similar to FIG. 4.  
         [0014]    [0014]FIG. 5 is a side view of an embodiment of the present invention.  
         [0015]    [0015]FIG. 6 is a perspective view taken from above of an embodiment of the present invention, directed to a clip.  
         [0016]    [0016]FIG. 7 is a perspective view taken from below of an embodiment of the present invention, directed to a clip. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]    The invention relates to a number of features in a printer cartridge intended for use in an ink jet printer, although the invention is not limited to any particular field of use. The cartridge is described in overview, and then more particular aspects of the invention are described.  
         [0018]    With reference to FIG. 1, an exploded perspective view of a cartridge constructed according to an embodiment of the invention is shown. The cartridge includes a base  1  which generally defines the exterior of the cartridge along with a lid  2 . The base  1  and lid  2  define the interior space of the ink chamber. A foam reservoir  5  stores the ink in the ink chamber, as further discussed below. As used herein, “foam reservoir” is meant to include any material capable of absorbing ink from which the ink may then be extracted. The base  1  is shaped so as to mechanically key into a mating printhead. For example, the base  1  is shaped to fit into a particular printhead used in printers in current manufacture, but it could easily be shaped to fit into the printheads used in other printers.  
         [0019]    The cartridge lid  2  forms the top of the cartridge and forms the upper boundary of the cartridge. The lid  2  engages the base  1  and is preferably hermetically sealed therewith such as by ultrasonic welding.  
         [0020]    A retention clip  3  is situated within the interior space and engages ink base  1 . The engagement could by a number of means. In this embodiment, the clip  3  has posts  3   a  which fit into boss receptacles  1   a  formed within section of the base  1  that defines the interior space. The clip  3  holds the foam in place and, in one embodiment, compresses the foam reservoir  5 , as discussed below.  
         [0021]    A screen  4  is situated in the bottom interior surface of the base  1  directly over a nozzle port  1   b  formed in the bottom of the base  1 . The nozzle port  1   b  serves as the conduit through which ink is extracted from the cartridge. The purpose of the screen  4  is to filter ink of particulates and entrapped air as the ink passes from the foam reservoir  5  into the nozzle port.  
         [0022]    As noted above, the foam reservoir  5  absorbs and stores ink within the cartridge for the purpose of on-demand delivery of ink to the nozzle port  1   b . The ink is in turn supplied from the nozzle port  1   b  through a needle to the printhead.  
         [0023]    A nozzle plug  6  is an elastomeric plug that fits into a lower portion of the nozzle port and forms a fluid tight barrier at the bottom of the nozzle port by virtue of an interference fit between the plug  6  and the section of the base  1  defining the nozzle port. The plug  6  is pierced by the needle, and forms a fluid tight seal with the needle so that ink can only exit the fluid port through the needle.  
         [0024]    A feature of the base  1  is that it forms an essentially flat bottomed interior section floor  1   c , as shown in the Section view A-A (FIG. 4). The floor  1   c  supports the foam reservoir  5 . In one embodiment, floor  1   c  has a recessed pocket  1   d  for the purpose of receiving the screen  4  so that screen  4  will form a flush surface and the interior surface  1   c  will be substantially flat even at the interface of the screen  4  and the remainder of the floor  1   c . In another embodiment, see FIG. 4 a , there is no recessed pocket, and the screen  4 ′ is a preferably fabric and is placed over the entirety of the floor  1   c , again resulting in a flat surface. The flat surface of the floor  1   c  may be contrasted with the ridged surface of comparable previous ink cartridges.  
         [0025]    The lid  2  has a flat lower surface, as shown in FIG. 4. The flat lower surface  2   a  avoids any interference with the clip  3  after assembly of the cartridge. The lid  2  is spaced away from the clip  3  to form a void space V between the therebetween. The void space V allows for gas communication between the interior space and the exterior of the cartridge (i.e., the atmosphere), through vent hole  2   b . Further, the lid  2  has a through hole  2   c  allowing for the automated injection fill of the foam reservoir  5 . The through hole  2   c  may be plugged after assembly.  
         [0026]    In an embodiment, the clip  3  provides compression of the foam reservoir  5  in the top to bottom direction of the cartridge by creating a distance between the floor  1   c  and the clip that is less than the height of the foam reservoir in the absence of any pressure. This compression of the foam reservoir  5  regulates ink flow towards the nozzle port during use of the cartridge. The use of the clip allows compression of the foam, without using protrusions from the lid  2 . The clip  3  is at least somewhat less wide than the interior space defined by the base  1  and lid  2 , so that the foam reservoir  5  communicates directly with void space V. The clip  3  has a hole  3   b  allowing injection filling of the foam reservoir  5 . In another embodiment, the clip does not provide compression but instead serves to retain the foam reservoir  5  in place. I.e., the distance between the floor  1   c  and the clip  3  is approximately the same as the height of the foam reservoir  5 .  
         [0027]    Another aspect of the invention is the incorporation of variable vertical position of the clip  3  to allow for customization of the top-bottom compression of the foam reservoir  5 , and/or for different foam reservoir heights even if the clip  3  does not compress the foam reservoir  5 . A higher position of the clip  3  (i.e., closer to the lid  2 ) will cause less compression and/or accommodate a higher foam reservoir  5  than a lower position. In a preferred embodiment, the variation is caused by varying the length of the posts  3   a . With reference to FIG. 4, longer posts  3   a  cause the clip  3  to be closer to the lid  2  than shorter posts, and thus making the posts  3   a  longer causes less compression and making the posts  3   a  shorter causes relatively greater compression. It will thus be appreciated that very simple adjustments allow for variation of the level of compression of the foam reservoir  5  or adjustment of the height of the foam  5 . Variable vertical position may be caused by other means, all of which may be incorporated into the present invention.  
         [0028]    An optional feature of the foam reservoir  5  is the inclusion of notches  5   a  along the vertical length of the reservoir  5  that provide clearance for the boss receptacles  1   a . This allows the foam reservoir  5  to be seated within the interior space without any void spaces between the foam reservoir  5  and the interior walls of the base  1 . There is of course a void space between foam reservoir and the lid  2 , as discussed above.  
         [0029]    Another aspect of the invention is described in connection with FIGS. 6 and 7. A clip having generally the same functionality and purpose as clip  3  is denoted as reference number  7 . It is formed of 2 pieces  7   a  and  7   b  that engage each other at a variable position to allow for overall variance of the length of clip  7 . Piece  7   b  slides into a groove  7   c  formed within piece  7   a  to form a tongue and groove connection. Piece  7   b  has a raised protrusion  7   d  which forms a detent element with a series of mating receptacles  7   e  formed above the groove  7   c  in piece  7   a . Sliding piece  7   b  so that protrusion  7   d  engages various receptacles  7   e  (one of which is shown; the invention includes any desired number) adjusts the width of clip  7  to a desired width. This allows the same clip  7  to be used in various designs of a cartridge according to the present invention having varying widths, thus saving in tooling and manufacturing costs.  
         [0030]    It will be appreciated that a number of features of the cartridge have been described above, and that not every feature need be incorporated into any particular embodiment of the invention disclosed herein. Further, the scope of any claims arising from this application shall be limited only by the scope and content of the prior art.