Patent Publication Number: US-7216964-B2

Title: Strain relief for ink cartridge ink supply tube

Description:
BACKGROUND OF THE INVENTION 
   This invention relates to the art of ink cartridges for ink jet printers and, more particularly, to arrangements for relieving the strain on an ink supply line to an ink cartridge in a continuous ink supply system. 
   Continuous ink refill systems for disposable ink jet cartridges are well known as shown, for example, in U.S. Pat. No. 5,469,201 to Erickson, et al. and U.S. Pat. No. 5,745,137 to Scheffelin, et al., both of which are incorporated herein by reference for background information. Basically, in such a continuous ink refill system, a cartridge is connected to an auxiliary ink supply reservoir by means of a flexible hose or tube, and during operation of the printing system, the tube is open to allow ink to flow from the auxiliary reservoir to the ink cartridge. During shipment or handling of the ink supply reservoir/cartridge system when it is outside the printer, as well as during the installation and removal of the system relative to a printer, it is important that the connection of the supply tube to the cartridge be leak tight to preclude the leakage of ink within the cartridge assembly, onto exterior surfaces of the cartridge, into a container in which the ink supply reservoir system is packaged, and/or onto surfaces within the printer. In connection with maintaining a leak tight connection for the latter purposes, it is important to optimize protection of the supply tubing from becoming disconnected from the cartridge during use and/or handling. 
   Heretofore, as shown for example in the aforementioned patent to Erickson, et al., the ink supply tube extends into a cartridge through an opening in a wall thereof and the tubing is bonded to the cartridge at the opening to provide strain relief against separation of the tubing from the cartridge. In the patent to Scheffelin, et al., the supply tubing is coupled to the cartridge through the cartridge handle and a slidably interengaged coupling arrangement. Neither of these arrangements secures the tubing relative to the cartridge so as to preclude the direct application of force axially of the tubing which can result in separation thereof from the cartridge and, accordingly, neither arrangement provides an adequate relief of or protection against strain on the tubing at the point of connection with the cartridge. 
   SUMMARY OF THE INVENTION 
   In accordance with the present invention, strain relief arrangements are provided for optimizing protection of the ink supply tubing from the direct application of a force tending to separate the tubing from the cartridge at the point of connection therebetween. More particularly in accordance with the invention, the tubing is routed through the handle of a cartridge so as to provide a bend in the tubing between the point of connection and the handle. The bend precludes pulling on the tubing at a point beyond the handle toward the ink supply reservoir which would be directly applied to the point of connection between the tubing and cartridge. At least partially in this respect, any such force applied to the tubing will be transferred to or imposed on the handle rather than to the tubing of the point of connection with the cartridge. The routing may provide for a second bend in the tubing relative to the handle which further restrains or precludes the application of a pulling force on the tubing at the point of connection thereof with the cartridge. Preferably, the tubing is connected in flow communication with the ink chamber of the cartridge through an L-shaped coupling mounted on the top wall of the cartridge and having a leg parallel to the top wall and extending to the cartridge handle, whereby the tubing connection to the cartridge provides a low profile which further protects against separation of the tubing from the cartridge. 
   It is accordingly an outstanding object of the present invention to provide improved strain relief arrangements for flexible ink supply tubing connected to an ink cartridge used in a continuous ink refill system for disposable ink cartridges. 
   Another object is the provision of strain relief arrangements of the foregoing character in which the flexible tubing is routed through openings in the handle of a cartridge such that pulling forces on the tubing are imposed on the handle and are restrained from being imposed on the tubing at the point of connection thereof with the cartridge. 
   A further object is the provision of strain relief arrangements of the foregoing character which provide a low profile with respect to the routing of the tubing from the cartridge to the openings through the handle, thus to further protect the tubing at the point of connection thereof with the cartridge. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing objects, and others, will in part be obvious and in part pointed out more fully hereinafter in conjunction with the written description of preferred embodiments of the invention illustrated in the accompanying drawings in which: 
       FIG. 1  is a perspective view of an ink cartridge having a strain relief arrangement according to the invention for flexible ink supply tubing connected to the cartridge; 
       FIG. 2  is an enlarged cross-sectional view of the strain relief arrangement taken along line  2 — 2  in  FIG. 1 ; 
       FIG. 3  is a perspective view of an ink jet cartridge having another strain relief arrangement for the ink supply tubing connected thereto; and, 
       FIG. 4  is an enlarged cross-sectional view of the strain relief arrangement taken along line  4 — 4  in  FIG. 3 . 
   

   DESCRIPTION OF PREFERRED EMBODIMENTS 
   Referring now in greater detail to the drawings, wherein the showings are for the purpose of illustrating preferred embodiments of the invention only, and not for the purpose of limiting the invention,  FIGS. 1 and 2  illustrate an ink cartridge  10  which is adapted to be connected to an ink reservoir, not shown, by flexible ink supply tubing  12  to provide a continuous refill system for the cartridge. Cartridge  10  includes a top side  14 , a front side  16  and a handle  18  at the juncture between the top and front sides, and tubing  12  is routed through handle  18  as described more fully hereinafter and is connected to the ink chamber C of cartridge  10  through a coupling element  20 . More particularly in this respect, coupling  20  has a leg  20   a  extending through top side  14  and opening into chamber C and a leg  20   b  extending parallel to top side  14  and toward handle  18 . 
   Handle  18  includes a top wall  22 , a bottom wall  24 , and a front wall  26  therebetween and has laterally opposite sides, one of which is closed by a side wall  28  and the other of which is open as designated by numeral  30 . Top wall  22  is provided with an opening  32  and bottom wall  24  is provided with an opening  34 , which openings are generally centrally between the opposite sides of the handle, and tubing  12  includes a section  12   a  extending upwardly through openings  32  and  34  and a section  12   b  which extends inwardly from section  12   a  and has a terminal end receiving leg  20   b  of coupling element  20 . This routing of tubing  12  provides a bend  12   c  between sections  12   a  and  12   b,  and the disposition of leg  20   b  of the coupling element advantageously provides for tubing section  12   b  to extend parallel to and closely adjacent top side  14  of the cartridge, thus to provide a low profile for the connection. It will be appreciated that the interengagement between tubing  12  and openings  32  and  34  in handle  18  restrains any displacement of the tubing downwardly relative to the handle in response, for example, to the application of a downward force on the tubing from a location below the handle. While it is preferred to provide an L-shaped coupling for connecting the tubing with ink chamber C, it will be appreciated that other coupling configurations can be used and that the tubing can be directly connected with the ink chamber such as by extending through an opening in the top of the cartridge. In the latter instance, the tubing would be adhesively bonded or otherwise sealed relative to the cartridge against the leakage of ink from the chamber. 
     FIGS. 3 and 4  illustrate a modification of the strain relief arrangement shown in  FIGS. 1 and 2 . The modification involves a different routing of tubing  12  relative to handle  18  and does not necessarily require a modification of the cartridge and handle structure shown in  FIGS. 1 and 2 . Accordingly, the same numerals and characters are used in the drawings of both embodiments. In the embodiment of  FIGS. 3 and 4 , section  12   a  of tubing  12  is routed downwardly through opening  32  in top wall  22  of the handle and thence outwardly through open side  30  of the handle. This routing provides a second, somewhat S-shaped, bend in section  12   a  between bend  12   c  and the section  12   d  of the tubing outwardly adjacent open end  30  of the handle. The second bend further restrains displacement of tubing  12  relative to the handle in a manner which would apply a pulling force to the tubing at the connection thereof with coupling  20 . It will be appreciated, of course, that opening  34  in bottom wall  24  of the handle is not necessary in connection with this routing. At the same time, however, opening  34  provides a user with the option of choosing the one of the two possible routings which might be preferred in a particular printer environment. Further, while handle  18  in the embodiments disclosed herein has an open side  30 , it will be appreciated that an opening for the tubing could be provided in wall  28  at the closed side of the handle should it be desired to route the tubing in the latter direction. 
   While considerable emphasis has been placed herein on the structures of the preferred embodiments illustrated and described, it will be appreciated that other embodiments can be devised and that more applications can be made in the preferred embodiments without departing from the principals of the invention. Accordingly, it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention, and not as a limitation and that it is intended to include other embodiments and all modifications of the preferred embodiments insofar as they come within the scope of the appended claims or the equivalents thereof.