Abstract:
A liquid supply joint device whose structure is simplified and that is accordingly composed of a small number of components, is small in size, can be manufactured at low cost, and can prevent liquid leakage under a wide range of conditions without being affected by internal pressure, whether high or low, is provided. The liquid supply joint device includes: a housing  10  that can be placed at at least one of the liquid reservoir and the liquid accepter and has a liquid supply port  11  and a discharge port  12 ; and a valve body  50  that is placed and movable in the housing  10  and opens or closes the supply port  11  or the discharge port  12  in accordance with movement of the valve body  50 . Either the housing  10  or the valve body  50  is composed of an elastic member. The valve body  50  has a sealing face  53  that is generally parallel to the direction of its movements, and the valve body  50  is closed when the sealing face  53  is made to come into contact with the inside wall of the housing  10.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS  
       [0001]     This application relates to and claims priority from Japanese Patent Application No. 2005-340562, filed on Nov. 25, 2005, the entire disclosure of which is incorporated herein by reference.  
       BACKGROUND  
       [0002]     1. Technical Field  
         [0003]     The present invention relates to a liquid supply joint device for guiding a liquid from a liquid reservoir to a liquid accepter in a liquid supply means for, for example, a fuel cell or an ink-jet printer. This invention also relates to a fuel cell system equipped with such a liquid supply joint device.  
         [0004]     2. Related Art  
         [0005]     A liquid supply means to which a liquid reservoir containing and discharging a liquid, and a liquid accepter for receiving the liquid from the liquid reservoir, can be attached is now widely used for, for example, ink-jet printers, lighters using liquid fuel, and chemical liquid administration for medical treatment. In the liquid supply means, the liquid reservoir itself can be directly replaced when it runs short of the liquid to be supplied. Accordingly, compared to the case where the liquid is supplied directly to, for example, a reserve tank mounted on a main body of the liquid supply means, users can supply the liquid to the liquid reservoir more easily and safely without dirtying their hands so much with the liquid. In particular, this liquid supply means is very effective in the case where the liquid to be supplied has an affect on the human body or may severely deteriorate if exposed to the outside air.  
         [0006]     Also, the development of fuel cells that generate electric power by using a liquid as fuel is being promoted these days. In particular, many electric-appliance makers are actively promoting the development of direct methanol fuel cells (DMFC) that use methanol as fuel. The DMFCs are expected to be new batteries for the next generation that can be used for, for example, notebook personal computers, various portable electronics, and cell phones. However, in general, methanol has a considerable affect on the human body. If man inhales methanol, it may damage the central nervous system and cause dizziness and diarrhea. If man inhales a large amount of methanol or methanol enters his eyes, methanol may cause optic nerve disorder and there is a high possibility of loss of sight. Accordingly, methanol is a highly dangerous toxic liquid. Therefore, in order to safely and easily supply fuel to general consumers of DMFCs, a means of supplying methanol to a liquid reservoir as a cartridge without directly touching methanol is considered to be the optimum means, and the development of such means is being widely promoted. (See, for example, JP2003-308871 A, JP8-12301 A, and JP2003-317756 A).  
         [0007]     The above-described liquid supply means needs to have a liquid supply joint device that guides the liquid from a liquid reservoir to a liquid accepter and can be attached to the liquid reservoir and/or the liquid accepter. Various types of conventional joint devices have been introduced. (See, for example, JP10-789 A, JP8-50042 A, JP 2003-528699 T, JP2003-266739 A, JP2001-524896 T, JP2000-289225 A, JP7-68780 A, JP5-254138 A, and JP2003-331879 A).  
         [0008]     However, since all of these joint devices have many components and complicated structures, there are size and cost reduction limitations. Moreover, since the joint device is structured so that a valve or similar opens when supplying a liquid, liquid leakage may easily occur if the internal pressure of the liquid reservoir and the accepter increases. Accordingly, there is a strong need for a joint device whose joint structure is simplified, that does not cause liquid leakage under high internal pressure, and that can be smoothly attached to the liquid reservoir and/or liquid accepter.  
         [0009]     In the case of a joint device that is structured to close its valve to stop the liquid supply, and of the type that is sealed by causing a surface of the valve generally perpendicular to the valve movement direction (“generally parallel surface”) to come into contact with the inside wall of the housing in which the valve is placed, it is necessary to secure a certain amount of area of the generally parallel surface in order to seal the valve with certainty. As a result, a large area of the valve is exposed from the liquid reservoir cartridge. This is one of factors that make it difficult to reduce the size of the joint device and therefore the size of the liquid reservoir.  
       SUMMARY  
       [0010]     The present invention was devised in light of the circumstances described above. It is an object of the invention to provide: a liquid supply joint device whose structure is simplified and that is composed of a small number of components, is small in size, can be manufactured at low cost, and can prevent liquid leakage under a wide range of conditions without being affected by internal pressure, whether high or low; and a fuel cell system equipped with such a liquid supply joint device.  
         [0011]     In order to achieve the above-described object, according to an aspect of the invention, a liquid supply joint device for connecting a liquid reservoir containing a liquid to a liquid accepter for receiving the liquid from the liquid reservoir is provided. This liquid supply joint device includes: a housing that can be placed at at least one of the liquid reservoir and the liquid accepter and has a liquid supply port and a discharge port; and a valve body that is placed and movable in the housing and opens or closes the supply port or the discharge port in accordance with movements of the valve body, wherein either the housing or the valve body is composed of an elastic member, and wherein the valve body has a sealing face that is generally parallel to the direction of its movement, and the valve body is closed when the sealing face is made to come into contact with the inside wall of the housing.  
         [0012]     The liquid supply joint device having the above-described structure is configured so that the valve is closed by positioning the sealing face of the valve body generally parallel to the movement direction of the valve body and making the sealing face come into contact with the inside wall of the housing. Accordingly, it is possible to simplify the structure, reduce the number of components, realize a size reduction, manufacture the liquid supply joint device at low cost, and prevent liquid leakage under a wide range of conditions without being affected by internal pressure, whether high or low.  
         [0013]     In the liquid supply joint device according to the invention, the housing can be composed of an elastic member. Accordingly, in addition to the advantageous effects described above, the sealing face of the valve body can be made to come into contact with the inside wall of the housing with more certainty.  
         [0014]     The liquid supply joint device according to the invention may also be configured so that a force-applying member for applying force to the valve body to make it move is provided in the housing.  
         [0015]     Moreover, the liquid supply joint device according to the invention may be configured so that a force-applying member for applying force to the valve body to make it move is formed integrally with the inside wall of the housing.  
         [0016]     Furthermore, the valve body may be configured so that channels for allowing the liquid to flow through are formed at an end portion of the valve body on the side to be closed; and when the valve body is opened, the liquid is made to flow through the channels.  
         [0017]     The valve body can be configured so that when the valve body moves, the sealing face slides along the inside wall of the housing.  
         [0018]     Furthermore, the liquid supply joint device according to the invention may be configured so that either at least the sealing face of the valve body or at least a sliding face of the housing along which the sealing face slides, or both are made of a sliding material. Accordingly, in addition to the advantageous effects described above, the valve body can be moved more smoothly.  
         [0019]     Also, according to an aspect of the invention, a fuel cell system including: a fuel cell; a liquid reservoir containing liquid fuel; a liquid accepter for receiving the liquid fuel from the liquid reservoir and supplying it to the fuel cell; and the aforementioned liquid supply joint device is provided.  
         [0020]     Since the fuel cell system having the above-described structure is equipped with the liquid supply joint device having the advantageous effects described above, it is possible to simplify its structure, reduce the number of components, realize the size reduction, and manufacture the fuel cell system at low cost.  
         [0021]     Also, the liquid fuel for the fuel cell system according to the invention can contain methanol.  
         [0022]     As described above, the liquid supply joint device according to the invention is configured so that the valve body is closed by making the sealing face, which is generally parallel to the movement direction of the valve body, come into contact with the inside wall of the housing. Accordingly, it is possible to simplify its structure, reduce the number of components, realize a size reduction, and manufacture the liquid supply joint device at low cost. Also, the liquid supply joint device has the effect of preventing liquid leakage under a wide range of conditions without being affected by internal pressure, whether high or low.  
         [0023]     Furthermore, since the fuel cell system according to the invention is equipped with the liquid supply joint device according to the invention, it has the effect of simplifying its structure, reducing the number of components, realizing a size reduction, and manufacturing the fuel cell system at low cost. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0024]      FIG. 1  is a cross-sectional view of a liquid supply joint device according to the first embodiment of the invention where its valve body is in the closed position.  
         [0025]      FIG. 2  is a cross-sectional view of the liquid supply joint device according to the first embodiment where its valve body is in the open position.  
         [0026]      FIG. 3  is a plan view of the valve body for the liquid supply joint device in  FIGS. 1 and 2 , as seen from the left side of  FIG. 1 .  
         [0027]      FIG. 4  is a side view of the valve body for the liquid supply joint device in  FIGS. 1 and 2 .  
         [0028]      FIG. 5  is a cross-sectional view of a liquid reservoir housing to which the liquid supply joint device shown in  FIGS. 1 and 2  is attached, and a liquid accepter housing to be connected to the liquid reservoir housing before they are connected to each other.  
         [0029]      FIG. 6  is a cross-sectional view of the housings in  FIG. 5  when they are connected to each other via the liquid supply joint device in  FIGS. 1 and 2 .  
         [0030]      FIG. 7  is a cross-sectional view of a liquid supply joint device according to the second embodiment of the invention when it is attached to a housing and its valve body is in the closed position.  
         [0031]      FIG. 8  is a cross-sectional view of a liquid reservoir housing to which the liquid supply joint device shown in  FIG. 7  is attached, and a liquid accepter housing to be connected to the liquid reservoir housing before they are connected to each other.  
         [0032]      FIG. 9  is a cross-sectional view of the housings shown in  FIG. 8  when they are connected to each other via the liquid supply joint device.  
         [0033]      FIG. 10  is a cross-sectional view of a housing to which a liquid supply joint device according to another embodiment of the invention is attached, and a liquid accepter housing to be connected to the liquid reservoir housing before they are connected to each other.  
         [0034]      FIG. 11  is a cross-sectional view of the housings shown in  FIG. 10  when they are connected to each other via the liquid supply joint device.  
         [0035]      FIG. 12  is a cross-sectional view of a housing to which a liquid supply joint device according to another embodiment of the invention is attached, and a liquid accepter housing to be connected to the liquid reservoir housing before they are connected to each other.  
         [0036]      FIG. 13  is a cross-sectional view of the housings shown in  FIG. 12  in when they are connected to each other via the liquid supply joint device.  
         [0037]      FIG. 14  is a cross-sectional view of a housing to which a liquid supply joint device according to another embodiment of the invention is attached, and a liquid accepter housing to be connected to the liquid reservoir housing before they are connected to each other.  
         [0038]      FIG. 15  is a cross-sectional view of the housings shown in  FIG. 14  when they are connected to each other via the liquid supply joint device.  
         [0039]      FIG. 16  is a schematic diagram of a fuel cell system according to the first embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0040]     A liquid supply joint device according to preferred embodiments of the invention will be described below with reference to the attached drawings. The embodiments described below are for the purpose of describing this invention, but the invention is not limited only to those embodiments. Accordingly, this invention can be utilized in various ways unless those utilizations depart from the gist of the invention.  
       First Embodiment  
       [0041]      FIG. 1  is a cross-sectional view of a liquid supply joint device according to the first embodiment of the invention where its valve body is in the closed position.  FIG. 2  is a cross-sectional view of the liquid supply joint device according to the first embodiment where its valve body is in the open position.  FIG. 3  is a plan view of the valve body for the liquid supply joint device in  FIGS. 1 and 2 , as seen from the left side of  FIG. 1 .  FIG. 4  is a side view of the valve body for the liquid supply joint device in  FIGS. 1 and 2 .  FIG. 5  is a cross-sectional view of a liquid reservoir housing to which the liquid supply joint device shown in  FIGS. 1 and 2  is attached, and a liquid accepter housing to be connected to the liquid reservoir housing.  FIG. 6  is a cross-sectional view of the housings in  FIG. 5  when they are connected to each other via the liquid supply joint device in  FIGS. 1 and 2 .  
         [0042]     As shown in FIGS.  1  to  6 , a liquid supply joint device  1  according to the first embodiment is a device for connecting a liquid reservoir containing a liquid to a liquid accepter for receiving the liquid from the liquid reservoir. The liquid supply joint device  1  includes: a housing  10 ; a valve body  50  placed in the housing  10  in such a way that the valve body  50  can move in the housing  10 ; and a spring  80  for applying force to the valve body  50 .  
         [0043]     The housing  10  is made of an elastic member (a material that can elastically change its shape), and can contain a liquid. This housing  10  has: a supply port  11  for supplying the liquid from a liquid reservoir (not shown in the drawing) into the housing  10 ; and a discharge port  12  for discharging the liquid contained in the housing  10  to a liquid accepter (not shown in the drawing). Also, a valve-body-press-in part  13  of a generally cylindrical shape that is complementary to the shape of the valve body  50 , and into which the valve body  50  can be pressed, and along which the pressed-in valve body  50  can slide, is formed inside the housing  10  on the discharge port  12  side. Furthermore, a valve seat  18  for fastening one end of a spring  80  described later in detail is formed inside the housing  10  on the supply port  11  side.  
         [0044]     Various known elastic materials such as various types of rubbers and elastomers can be used as materials for the housing  10 . Specific examples of the elastic materials include: styrene butadiene rubber, butadiene rubber, syndiotactic 1,2-polybutadiene, isoprene rubber, acrylonitrile-butadiene rubber, chloroprene rubber, ethylene-propylene rubber, ethylene-propylene terpolymer, butyl rubber, acrylic rubber, chlorosulfonated polyethylene, silicon rubber, vinylidene fluoride-hexafluoropropylene rubber, tetrafluoroethylene-propylene rubber, tetrafluoroethylene perfluoromethyl vinyl ether rubber, fluorosilicon rubber, epichlorohydrin rubber, polysulfide rubber, urethane rubber, and natural rubber. One of these rubber types or a combination of two or more types can be used. It is desirable to select the material of the housing  10  according to the properties of the liquid to be sent or received, and according to the properties of the elastic member such as slide, permanent compressive strain, rebound resilience, and elution resistance. If the liquid reservoir is a methanol fuel cartridge used in a DMFC and a 3 wt % methanol solution is to be sealed in the liquid reservoir, ethylene-propylene rubber, which has excellent methanol resistance and permanent compressive strain, can be used. In this case, the liquid accepter can contain a DMFC main body (product number 6061; manufactured by Eifrig Inc.).  
         [0045]     Ribs  14 A and  14 B for attaching the housing  10  to a liquid reservoir housing  100  (see  FIGS. 5 and 6 ) are formed on the outside surface of the housing  10  on the supply port  11  side. The ribs  14 A and  14 B may be attached to the housing  100  in such a way that liquid leakage will not be caused from the part attached to the housing  100 . In order to prevent leakage from the part attached to the housing  100 , the housing  10  and the housing  100  may be integrally molded by means of, for example, insert molding or two-color molding.  
         [0046]     A labyrinth seal  15  of a protruding shape is formed on the outside end face  16  of the housing  10  on the discharge port  12  side. This labyrinth seal  15  may be formed so that it protrudes from the outside end face  16  around the discharge port  12 . Incidentally, the cross-section of the protruding part of the labyrinth seal  15  in the first embodiment has a semicircle shape. However, the cross-sectional shape of the protruding part of the labyrinth seal  15  is not particularly limited and may be a reversed V shape or a quadrangle. Also, the outside end face  16  constitutes a joint face to be connected to a liquid accepter housing  200  (see  FIGS. 5 and 6 ).  
         [0047]     A labyrinth seal  202  of a protruding shape, which will be described later in detail, is formed on a joint face  201  of the housing  200  (see  FIGS. 5 and 6 ) to come into contact with the outside end face  16  of the housing  10 . This labyrinth seal  202  is formed so that it will be located at a position offset from the labyrinth seal  15  when the outside end face  16  (the joint face ) of the housing  10  touches the joint face  201  of the housing  200 . Accordingly, when the outside end face  16  of the housing  10  is connected to the joint face  201  of the housing  200 , dual labyrinth seal effects can be obtained. As a result, it is possible to prevent liquid leakage with certainty and ensure high reliability.  
         [0048]     In some cases, the labyrinth seals  15  and  202  may not necessarily be formed because a contact pressure between the outside end face  16  and the joint face  201  is high or the outside end face  16  and the joint face  201  have high adhesiveness to each other when the liquid reservoir housing  100  is connected to the liquid accepter housing  200  via the liquid supply joint device  1 . Also, either of the labyrinth seals  15  and  202  may be provided. Furthermore, the labyrinth seals  15  and  202  can be designed in consideration of, for example, connection conditions and the materials for the housing  10  in order to prevent liquid leakage.  
         [0049]     The valve body  50  has a generally cylindrical shape so that it can be pressed into the valve-body-press-in part  13 , which is generally cylindrical and is formed inside the housing  10 , and can slide along the valve-body-press-in part  13 . This valve body  50  has channels  51  formed therein on its one end portion closer to the discharge port  12  side of the housing  10 . As shown in  FIG. 3 , these channels  51  are composed of generally-cross-shaped grooves on the end face  52  of the valve body  50  opposite the discharge port  12 . The valve body  50  can move in the valve-body-press-in part  13  in back-and-forth movement directions relative to the discharge port  12  (from side to side as shown in  FIGS. 1 and 2 ). The outside side surface of the valve body  50  (i.e., the surface generally parallel to the movement directions of the valve body  50 ) constitutes a sealing face  53  that can seal a space between the valve body  50  and the inside wall of the valve-body-press-in part  13 .  
         [0050]     When a force applied by the spring  80 , whose one end is fastened to the valve seat  18  formed inside the housing  10  and other end is fastened to one end portion of the valve body  50 , causes a portion of the valve body  50 , including the area where the sealing face  53  is formed, to be inserted into the valve-body-press-in part  13  (see  FIG. 1 ), the valve  50  is closed and liquid discharge to the liquid accepter is stopped. On the other hand, when a valve-body-pressing pin  203  (see  FIGS. 5 and 6 ) attached to the liquid accepter housing  200  presses the valve body  50  toward the supply port  11  and causes a portion of the valve body  50 , i.e., part of the area where the channels  51  are formed, to be inserted into the valve-body-press-in part  13 , the channels  51  are partly exposed from the valve-body-press-in part  13  (see  FIG. 2 ), thereby opening the valve body  50  and discharging the liquid through the channels  51  to the liquid accepter. Incidentally, the valve body  50  is normally open because of the force applied by the spring  80 .  
         [0051]     There is no particular limitation on types of materials to be used to form the valve body  50  as long as the valve body  50  can be pressed into and slide along the valve-body-press-in part  13  and can seal the space between the valve body  50  and the inside wall of the valve-body-press-in part  13 . However, examples of the material of the valve body  50  can include metals, plastics, woods, and ceramics. Of those, metals and plastics are more preferable. Specific examples of the metals include: stainless steel, aluminum, iron, copper, silver, platinum, and gold. Specific examples of the plastics include: polyethylene, polypropylene, polyvinyl chloride resin, polystyrene, ABS resin, methacrylic resin, polyethyleneterephthalate, polyamide, polycarbonate, polyacetal, polybutylene terephthalate, modified polyphenylene ether, polyphenylene sulfide, liquid crystal polymer, polysulfone, polyether sulfone, polyallylate, polyether ether ketone, polyphthal amide, polyimide, polyether-imide, polyamide-imide, polymethyl pentene, fluororesin, polyvinylidene fluoride, TEFE, PFA, phenolic resin, urea resin, melamine resin, unsaturated polyester, diallyl phthalate, epoxy resin, polyurethane resin, and silicon resin. Regarding the first embodiment, polypropylene, which is highly resistant to methanol, is used in consideration of the fact that it is used in a DMFC.  
         [0052]     As shown in  FIGS. 5 and 6 , the liquid reservoir housing  100  has a protruding part  101  that engages with a recess defined by the ribs  14 A and  14 B formed on the housing  10  of the liquid supply joint device  1 . The liquid supply joint device  1  is attached to the liquid reservoir by having the protruding part  101  engage with the recess between the rib  14 A and the rib  14 B. This housing  100  is structured so that its end face  110  to be connected to the housing  200  becomes flush with the end face closer to the discharge port  12 , of the rib  14 A of the housing  10 . Because of this structure, the liquid supply joint device  1  is attached to the housing  100  in such a way that the portion of the liquid supply joint device  1  extending from the rib  14 A toward the discharge port  12  protrudes from the end face  110  of the housing  100 .  
         [0053]     As shown in  FIGS. 5 and 6 , the liquid accepter housing  200  has a connection recess  210  for engaging with the protruding portion of the liquid supply joint device  1  that protrudes from the rib  14 A toward the discharge port  12  and also from the housing  100 , thereby connecting the liquid supply joint device  1  to the liquid accepter housing  200 . The aforementioned labyrinth seal  202  is formed on a joint face  201  of the connection recess  210 . Also, a valve-body-pressing pin  203  is formed on and protrudes from the substantially central part of the joint face  201  in such a way that the valve-body-pressing pin  203  can move back and forth.  
         [0054]     When the housing  100  is connected to the housing  200  and the liquid is allowed to flow from the liquid reservoir through the liquid supply joint device  1  to the liquid accepter, the valve-body-pressing pin  203  presses the valve body  50  toward the housing  100  against the force applied by the spring  80  and moves the valve body  50  to the open position, thereby opening the valve body  50 . The liquid supplied by the above-described action from the liquid reservoir into the housing  10  flows through the channels  51  formed in the valve body  50  and then a liquid supply passage  211  formed around the valve-body-pressing pin  203 , and finally reaches the liquid accepter.  
         [0055]     On the other hand, in order to stop the liquid flow into the liquid accepter, the valve-body-pressing pin  203  is moved backward to separate it from the valve body  50 , and the force applied by the spring  80  then moves the valve body  50  to the closed position, thereby closing the valve body  50 .  
         [0056]     If the liquid reservoir housing  100  is connected to the liquid accepter housing  200  via the liquid supply joint device  1  as shown in  FIG. 6 , the labyrinth seal  15  formed on the housing  10  of the liquid supply joint device  1  elastically changes its shape and becomes almost squashed, thereby further enhancing sealability.  
         [0057]     In a conventional liquid supply joint device (conventional product) that closes its valve by having a surface corresponding to the joint face  201  in the first embodiment come into contact with a surface corresponding to the outside end face  16 , it is necessary to secure a certain amount of area of the surfaces to be sealed (the surface corresponding to the joint face  201  in the first embodiment and the surface corresponding to the outside end face  16 ) in order to close the valve body with certainty. Accordingly, it is necessary to increase the radial length of the liquid supply joint device to a certain extent. This has been one of the factors that hamper the size reduction.  
         [0058]     On the other hand, in the case of the liquid supply joint device  1  according to the first embodiment, the valve body  50  is closed by sealing the space between the sealing face  53 , which is generally parallel to the movement direction of the valve body  50 , and the inside wall of the valve-body-press-in part  13 . Accordingly, it is unnecessary to increase the radial length of the liquid supply joint device and a size reduction can be achieved.  
         [0059]     If a fuel cell is used as the liquid accepter, the housing  200 , which is a fuel cell FC, may be connected via the liquid supply joint device  1  to the liquid accepter housing  100  containing liquid fuel as shown in  FIG. 16 .  FIG. 16  is a schematic diagram of a fuel cell system according to the first embodiment of the invention.  
         [0060]     The first embodiment described the case where the housing  10  is composed of an elastic member and the valve body  50  is composed of a material that cannot elastically change its shape so well compared to the housing  10 . However, the materials for the housing  10  and the valve body  50  are not limited to the examples described above, and the valve body  50  may be composed of an elastic member and the housing  10  may be composed of a material that cannot elastically change its shape so well compared to the valve body  50 . If the valve body  50  is composed of an elastic member, various known elastic materials such as various types of rubbers and elastomers can be used. Specific examples of the elastic materials include: styrene butadiene rubber, butadiene rubber, syndiotactic 1,2-polybutadiene, isoprene rubber, acrylonitrile-butadiene rubber, chloroprene rubber, ethylene-propylene rubber, ethylene-propylene terpolymer, butyl rubber, acrylic rubber, chlorosulfonated polyethylene, silicon rubber, vinylidene fluoride-hexafluoropropylene rubber, tetrafluoroethylene-propylene rubber, tetrafluoroethylene perfluoromethyl vinyl ether rubber, fluorosilicon rubber, epichlorohydrin rubber, polysulfide rubber, urethane rubber, and natural rubber. The rubber types can be used alone, or in combination.  
         [0061]     If the housing  10  is composed of a material that cannot elastically change its shape so well compared to the valve body  50 , materials such as metals, plastics, woods, and ceramics can be used. Of those, metals and plastics are more preferable. Specific examples of the metals include:  
         [0062]     stainless steel, aluminum, iron, copper, silver, platinum, and gold. Specific examples of the plastics include: polyethylene, polypropylene, polyvinyl chloride resin, polystyrene, ABS resin, methacrylic resin, polyethyleneterephthalate, polyamide, polycarbonate, polyacetal, polybutylene terephthalate, modified polyphenylene ether, polyphenylene sulfide, liquid crystal polymer, polysulfone, polyether sulfone, polyallylate, polyether ether ketone, polyphthal amide, polyimide, polyether-imide, polyamide-imide, polymethyl pentene, fluororesin, polyvinylidene fluoride, TEFE, PFA, phenolic resin, urea resin, melamine resin, unsaturated polyester, diallyl phthalate resin, epoxy resin, polyurethane resin, and silicon resin.  
         [0063]     In order to further improve the ability of the valve body  50  to slide along the valve-body-press-in part  13 , at least the sealing face  53  of the valve body  50  or at least the sliding face of the housing  10  along which the sealing face  53  slides may be formed of or coated with a sliding material.  
         [0064]     The first embodiment described the case where the liquid supply joint device  1  is placed in the liquid reservoir housing  100 . However, the configuration of the liquid supply joint device  1  is not limited to the above-described example, and the liquid supply joint device  1  may be placed in the liquid accepter housing  200 .  
       Second Embodiment  
       [0065]     Next, a liquid supply joint device according to the second embodiment of the invention will be described below with reference to the relevant drawings.  
         [0066]      FIG. 7  is a cross-sectional view of a liquid supply joint device according to the second embodiment of the invention when it is attached to a housing and its valve body is in the closed position.  FIG. 8  is a cross-sectional view of a liquid reservoir housing to which the liquid supply joint device shown in  FIG. 7  is attached, and a liquid accepter housing to be connected to the liquid reservoir housing before they are connected to each other.  FIG. 9  is a cross-sectional view of the housings shown in  FIG. 8  when they are connected to each other via the liquid supply joint device.  
         [0067]     Elements used in the second embodiment the same as those used in the first embodiment are given the same reference numerals as in the first embodiment, so their detailed description has been omitted.  
         [0068]     As shown in FIGS.  7  to  9 , the main difference between a liquid supply joint device  2  according to the second embodiment and the liquid supply joint device  1  according to the first embodiment is that the outside end face  26  of a housing  20  is generally flush with the end face  110  of the housing  100 .  
         [0069]     The housing  20  is formed so that the length of the housing  20  in the movement direction of the valve body  50  is shorter than that of the housing  10  in the liquid supply joint device  1  according to the first embodiment. A generally central part of the outside end face  26  is slightly raised compared to the outside area of that central part. However, the outside end face  26  as a whole is generally flush with the end face of the rib  14 A.  
         [0070]     In the case of this configuration, an end face  310  (joint face) of a liquid accepter housing  300  is generally flat as shown in  FIG. 8 . The liquid reservoir housing  100  is connected to the liquid accepter housing  300  via the liquid supply joint device  2  by having the outside end face  26  of the liquid supply joint device  2  come into contact with the end face  310  as shown in  FIG. 9 . Incidentally, in the second embodiment, the housing  100  and the housing  300  are fastened tightly by fastening means such as fittings, bolts, and screws not shown in the drawings.  
         [0071]     The action of the liquid flowing from the liquid reservoir to the liquid accepter via the liquid supply joint device  2  and the action to stop the liquid flow are similar to those of the liquid supply joint device  1  according to the first embodiment.  
         [0072]     If the liquid supply joint device  2  according to the second embodiment is applied, a liquid supply joint device  3  may be placed in a liquid accepter housing  400  as shown in  FIGS. 10 and 11 . The main difference between the liquid supply joint device  3  and the liquid supply joint device  2  is the structure of the valve body  150 . Specifically speaking, the difference between a valve body  150  and the aforementioned valve body  50  is that a valve-body-pressing pin  213  is set up from a generally central part of an end face  52  of the valve body  150 .  
         [0073]     As shown in  FIGS. 10 and 11 , the valve body  150  has the valve-body-pressing pin  213  which is set up from the generally central part of the end face  52 . When an end face  410  of the liquid accepter housing  400  in which the liquid supply joint device  3  is placed is positioned opposite, and then connected to, the end face  110  of the liquid reservoir housing  100  in which the liquid supply joint device  2  is placed as shown in  FIG. 11 , the valve-body-pressing pin  213 , instead of the valve-body-pressing pin  203 , presses the valve body  50 .  
         [0074]     Specifically speaking, before the housing  100  in which the liquid supply joint device  2  is placed is connected to the housing  400  in which the liquid supply joint device  3  is placed as shown in  FIG. 10 , the valve body  50  of the liquid supply joint device  2  is closed by the force applied by the spring  80 . Similarly, the valve body  150  of the liquid supply joint device  3  is closed by the force applied by the spring  80 .  
         [0075]     On the other hand, when the housing  100  in which the liquid supply joint device  2  is placed is connected to the housing  400  in which the liquid supply joint device  3  is placed as shown in  FIG. 11 , the valve-body-pressing pin  213  presses and moves the valve body  50  back toward the supply port  11  side of the liquid supply joint device  2  and, at the same time, the valve body  150  also moves back toward the supply port  11  side of the liquid supply joint device  3 , thereby opening both the valve bodies  50  and  150 . If the housing  100  is separated from the housing  400 , the valve bodies  50  and  150  are closed again by the force applied by the springs  80 . Accordingly, the liquid is made to flow from the liquid reservoir to the liquid accepter by making the housing  100  and the housing  400  be in contact with each other, and the liquid flow from the liquid reservoir to the liquid accepter is stopped by separating the housing  100  from the housing  400 .  
         [0076]     Incidentally, it is a matter of course that the liquid supply joint device  3  may be placed in the liquid reservoir housing  100  and that the liquid supply joint device  2  may be placed in the liquid accepter housing  400 .  
         [0077]     According to another embodiment, a liquid supply joint device  4  may be placed in the liquid reservoir housing  100  and the liquid accepter housing  400  as shown in  FIGS. 12 and 13 . The main difference between the liquid supply joint device  4  and the liquid supply joint device  2  is that a generally central part of the outside end face  26  of a housing  30  is raised outwards to form an inverted cup shape.  
         [0078]     Before the housing  100  in which the liquid supply joint device  4  is placed is connected to the housing  400  in which the liquid supply joint device  4  is placed as shown in  FIG. 12 , their valve bodies  50  are closed by the force applied by the springs  80  respectively. On the other hand, when the housing  100  in which the liquid supply joint device  4  is placed is connected to the housing  400  in which the liquid supply joint device  4  is placed as shown in  FIG. 13 , the inverted-cup-shaped part that bulges outwards from the outside end face  26  of each housing  30  changes its shape and becomes flat and pushes the valve body  50  toward the supply port  11  side, thereby opening both the valve bodies  50 . If the housing  100  is separated from the housing  400 , the inverted-cup-shaped part, which bulges outwards from the outside end face  26  of each housing  30 , elastically recovers its original shape, and each valve body  50  is closed by the force applied by the spring  80 . Accordingly, the liquid is made to flow from the liquid reservoir to the liquid accepter by making the housing  100  and the housing  400  be in contact with each other, and the liquid flow from the liquid reservoir to the liquid accepter is stopped by separating the housing  100  from the housing  400 .  
         [0079]     In the first and second embodiments, the spring  80  is provided as the force-applying member for applying force to the valve body  50  or the valve body  150 . However, like in liquid supply joint devices  5  and  6  shown in  FIGS. 14 and 15 , a force-applying part  180  that is integrally formed with the inside wall of the housing  20  and applies force to each valve body  250  and  350  toward its closed position may be provided instead of the spring  80 .  
         [0080]     In this case, the valve body  250  of the liquid supply joint device  5  placed in the liquid reservoir housing  100  has grooves  251  in its end face in contact with the force-applying part  180 , as shown in  FIGS. 14 and 15 . Because of these grooves  251 , the contact area of the end face of the valve body  250  in contact with the force-applying part  180  is reduced, so that the pressure imposed on the force-applying part  180  increases. Incidentally, the structure of the valve body  250  is similar to that of the aforementioned valve body  50 , except that the grooves  251  are formed in the valve body  250 .  
         [0081]     Similarly, the valve body  350  of the liquid supply joint device  6  placed in the liquid accepter housing  400  has grooves  251  in its end face in contact with the force-applying part  180  as shown in  FIGS. 14 and 15 . Because of these grooves  251 , the contact area of the end face of the valve body  350  in contact with the force-applying part  180  is reduced, so that the pressure imposed on the force-applying part  180  increases. Incidentally, the structure of the valve body  350  is similar to that of the aforementioned valve body  150 , except that the grooves  251  are formed in the valve body  350 .  
         [0082]     Before the housing  100  in which the liquid supply joint device  5  is placed is connected to the housing  400  in which the liquid supply joint device  6  is placed as shown in  FIG. 14 , the valve bodies  250  and  350  are closed respectively by the force-applying parts  180 . On the other hand, when the housing  100  in which the liquid supply joint device  5  is placed is connected to the housing  400  in which the liquid supply joint device  6  is placed as shown in  FIG. 15 , the valve-body-pressing pin  213  presses the valve body  250  toward the supply port  11  side of the liquid supply joint device  5 . As a result, the force-applying part  180  elastically changes its shape and the valve body  250  moves back toward the supply port  11  side of the liquid supply joint device  5 . Similarly, the opposing action causes the valve body  350  to be pushed toward the supply port  11  side of the liquid supply joint device  6 ; the force-applying part  180  elastically changes its shape; and the valve body  350  moves back toward the supply port  11  side of the liquid supply joint device  6 . As a result of this action, both the valve bodies  250  and  350  are opened.  
         [0083]     When the housing  100  is separated from the housing  400 , the force-applying parts  180  with elastic recovery power apply force to the valve bodies  250  and  350  respectively toward the discharge port  12  side, thereby closing the valve bodies  250  and  350  again. Accordingly, the liquid is made to flow from the liquid reservoir to the liquid accepter by making the housing  100  and the housing  400  in contact with each other, and the liquid flow from the liquid reservoir to the liquid accepter is stopped by separating the housing  100  from the housing  400 .  
         [0084]     Also in the structures according to other embodiments described above, the force-applying part  180  may be provided instead of the spring  80 . It is a matter of course that the liquid supply joint device  5  may be placed in the liquid reservoir housing  400  and that the liquid supply joint device  6  may be placed in the liquid accepter housing  100 .