Abstract:
A liquid container includes a box and a flexible bag accommodated in the box. The flexible bag contains a liquid and has a first end fixed at the box and a second end opposite to the first end and biased in a direction away from the first end by an elastic member. The box has two parts that are telescopically movable relative to one another and are biased apart by the elastic member. The bag is held at one of these parts with its first end and at the other of these parts with its second end.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a Continuation of International Application No. PCT/EP2014/053227, filed on Feb. 19, 2014, and for which priority is claimed under 35 U.S.C. §120. PCT/EP2014/053227 claims priority under 35 U.S.C. §119(a) to Application No. 13155975.9, filed in Europe on Feb. 20, 2103. The entire contents of each of the above-identified applications are hereby incorporated by reference into the present application. 
     
    
     BACKGROUND OF THE PRESENT INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a liquid container comprising a box and a flexible bag accommodated in the box. The flexible bag contains the liquid and has a first end and a second end, the first end being fixed at a wall part of the box. 
         [0004]    2. Description of Background Art 
         [0005]    Liquid containers of this type may, for example, be used for liquid ink for a printer or copier. 
         [0006]    JP 2012-183714 A describes an example of such a liquid container. The box, due to its regular shape and rigidity, facilitates handling and storage of the container, while the flexible bag provides a lightweight and liquid-tight enclosure that is easy to manufacture. When the bag is emptied, an elastic member tends to stretch the bag into a flattened state. 
         [0007]    EP 2 095 955 A1 discloses an ink cartridge that comprises a container body, a slider that encloses the container body, and an elastic member for urging the container body and the slider apart. Since the walls of the container body are not flexible, the container body does not collapse when the ink is consumed. In order to avoid the development of a vacuum in the container body, it is therefore necessary to permit air to enter into the container body. 
       SUMMARY OF THE PRESENT INVENTION 
       [0008]    It is an object of the present invention to provide a liquid container that is capable of collapsing into a flat state without forming wrinkles in which remnants of the ink would be retained. 
         [0009]    In order to achieve this object, the box according to the present invention has two parts that are telescopically movable relative to one another, an elastic member is provided for urging the two parts of the box apart, and said first end of the bag is fixed at one of the parts of the box and said second end of the bag is fixed at the other of the two parts of the box. 
         [0010]    When the bag is filled with liquid, the two telescopic parts of the box are in a retracted state, so that no space needs to be reserved, neither inside the box nor outside thereof, for permitting the bag to be stretched. Consequently, the box requires only little space during transport and storage. However, when the bag is being emptied, the elastic member causes the telescopic parts of the box to expand and thereby to stretch the bag into its flat state by drawing the opposite ends of the bag apart from outside. This not only prevents the bag from forming wrinkles, but has the additional advantage that the amount by which the telescopic parts are expanded and, therewith, the amount to which the bag has been emptied, is readily visible from the outside. 
         [0011]    More specific optional features of the present invention are indicated in the dependent claims. 
         [0012]    In a preferred embodiment, the one of the two parts of the box that is arranged to be telescopically moved out of the other part may have a scale that indicates the relative position of the two parts and, accordingly, the quantity of liquid left in the bag. 
         [0013]    Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the present invention will become apparent to those skilled in the art from this detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
           [0015]      FIG. 1  is a sectional view of a liquid container filled with liquid; 
           [0016]      FIG. 2  shows the liquid container of  FIG. 1  in the emptied state; 
           [0017]      FIG. 3  is an exploded perspective view of a box of the liquid container; 
           [0018]      FIGS. 4 and 5  are perspective views of the liquid container in the filled and emptied state, respectively; and 
           [0019]      FIG. 6  shows a supply cabinet of a printing system comprising a liquid container according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0020]    The present invention will now be described with reference to the accompanying drawings, wherein the same reference numerals have been used to identify the same or similar elements throughout the several views. 
         [0021]    The ink container shown in  FIG. 1  comprises a box  10  that accommodates a flexible bag  12 . The bag  12  is filled with a liquid, e.g. with liquid ink, maintenance liquid or media pretreatment liquid for an ink jet printer. 
         [0022]    The box  10  has two parts  14 ,  16  that are telescopically movable relative to one another. The part  14  (bottom part) has a bottom wall  18  and side walls  20 . The part  16  (top part) has a roof-shaped top wall  22  and side walls  24  that are held in sliding engagement with the internal surfaces of the side walls  20  of the bottom part  14 , so that the top part  16  is guided for vertical movement relative to the bottom part  14 . 
         [0023]    A spout  26  through which the liquid that is contained in the bag  12  may be withdrawn or poured out is mounted in the top wall  22  of the top part  16 , and a first end  28  of the bag  12  is fluid-tightly connected to the spout  26  and thus held rigidly at the top wall  22  of the part  16 . An opposite second part  30  of the bag  12  is fixed at the bottom wall  18  of the part  14 . 
         [0024]    An elastic member  32  is provided for biasing the two parts  14 ,  16  of the box  10  apart, i.e. for biasing the top part  16  upwardly relative to the bottom part  14 . In the example shown, the elastic member  32  takes the form of a coil spring, the windings of which extend along the side walls  20  of the part  14  so that a relatively large hollow space is left inside the spring, permitting the bag  12  to be attached at the bottom wall  18 . A lower end of the elastic member  32  is supported on the bottom wall  18  whereas the top end is supported at the lower edge of the side walls  24  of the top part  16 . 
         [0025]    In the condition shown in  FIG. 1 , the elastic member  32  is compressed into a flat state. Since the bag  12  is filled with liquid, it tends to retain an inflated state in which the volume is large enough to accommodate the liquid and, correspondingly, the distance between the first and second ends  28 ,  30  of the bag is relatively short. Since the ends of the bag are attached to the parts  14  and  16 , respectively, the bag  12  exerts a tensile force onto the two parts  14 ,  16  of the box, and this tensile force counterbalances the force of the elastic member  32 . 
         [0026]    However, when the bag  12  is emptied, it collapses into a flattened state, as has been shown in  FIG. 2 . This allows the first and second ends  28 ,  30  of the bag to be drawn apart under the force of the elastic member  32 , while the top part  16  of the bag is telescopically moved out of the bottom part  14 . In this embodiment, the flattened bag extends approximately along a diagonal plane of the internal cross-section of the box  10 . 
         [0027]    In  FIG. 3 , the bottom part  14  and the top part  16  of the box  10  have been shown separately. It will be understood that these parts of the box can easily be manufactured, e.g. from cardboard or semi-rigid plastics. 
         [0028]      FIG. 4  shows the box  10  in the collapsed state, i.e. in the condition in which the bag inside the box is filled with liquid.  FIG. 5  shows the box  10  in an expanded state, when the bag has been emptied to some degree. It can be seen here that one side wall of the top part  16  of the box is provided with a scale  34  that, together with the top edge of the side wall of the bottom part  14 , serves as an indicator for the amount of liquid still left in the bag. 
         [0029]    It is noted that the terms ‘bottom’, ‘side’ and ‘top’ as used above only indicate the relative positions of the respective walls of the two parts  14 ,  16  of the box  10  and are not to be used to limit the orientation of the box  10  when used in a printer or printing system. 
         [0030]    The liquid contained in the box  10  as shown in  FIG. 1  may be emptied out of the liquid container in various ways including using a pump and by gravity. 
         [0031]    In  FIG. 6 , a supply cabinet  50  of a printing system comprising six liquid containers according to the present invention is shown. The liquid containers ( 40 ,  41 ,  42 ,  43 ,  44  and  45 ) respectively contain cyan, magenta, yellow and black ink (CMYK); maintenance liquid, e.g. for flushing ink jet print heads, e.g. indicated with L1 and a primer liquid for pre-treating recording substrates, e.g. indicated with L2. In the cabinet, the orientations of liquid containers  40 ,  41 ,  42 ,  44 ,  45  are such that the spouts of the respective containers are the lowest parts of the liquid containers relative to the floor  60 , such that the liquids can be emptied out of the bags by gravity. By comparing liquid containers  40 ,  41  and  42 , it can be noticed that container  40  (cyan) is almost empty; container  41  (magenta) is approximately half full and container  42  (yellow) is almost full. Container  43  (black) is in a “changing position”. This position is such that an operator may be able to position a liquid container according to the present invention in the supply cabinet  50  and connect the spout  26  to the printer or printing system, e.g. via a hose (not shown) in an ergonomic way. After establishing a fluid connection between the liquid container and the printer or printing system, the liquid container  43  is tilted in a position similar to the shown positions of liquid containers  40 ,  41 ,  42 ,  44  and  45 . 
         [0032]    It will be understood that the shape of the top and bottom parts of the box  10  may be varied in various ways. Likewise, the elastic member  32  may have a different configuration. Instead of a compression spring, it would also be possible to use elastic tension elements, e.g. rubber straps that are fixed near the top edge of the side walls of the bottom part  14  with their top ends and near the bottom edge of the side walls of the top part  16  with their lower ends, so that they will lift the top part  16  when they tend to contract. The elastic member  32  may also be externally attached to the box, preferably to the bottom wall  18  with its lower end and to a wall of the supply cabinet with its top end. This configuration may be preferred from a cost point of view: the elastic member in this embodiment is not an integral part of the box and hence does not contribute to the costs of the box. An external elastic member (i.e. not contained within the box) can be reused over and over again. 
         [0033]    The present invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.