Abstract:
A toner container includes a container body having a mouth-piece member positioned at a mouth of the container body. The mouth-piece member includes an opening to allow toner to be discharged from the container body, a valve configured to seal the opening and which allows a nozzle located at a setting portion of an image forming apparatus to protrude into the valve, and a least two guides provided at opposite sides of the mouth-piece member configured to engage with at least two setting guides at the setting portion of the image forming apparatus.

Description:
This application is a continuation application of Ser. No. 09/963,644 filed Sep. 27, 2001, now U.S. Pat. No. 6,628,908, and claims priority under 35 U.S.C. §119 to application Ser. No. 2000-297354, filed Sep. 28, 2000, the entire contents of both of these applications being incorporated herein by reference. 

   FIELD OF THE INVENTION 
   The present invention relates to a toner supply unit having a toner container loaded detachably on a main body of the unit such that a toner discharging portion faces downward (in the direction of gravitational force), in which when the toner container is loaded on the main body of the unit, an insertion member is inserted into the toner discharging portion so as to supply toner through the insertion member. 
   BACKGROUND OF THE INVENTION 
   Conventionally, it has been well known that in an image forming apparatus such as a printer, copier and the like, a toner container for storing toner such as a toner bottle, a toner cartridge and the like is set up on the main body of the same apparatus and toner is supplied from the container to a developing portion. In this kind of the toner container, a toner discharging port is closed with a cap or seal so that upon replacement of the container, user has to remove that cap or seal. However, this work causes scattering of toner or contamination by toner, therefore user does not like to do such a work. Thus, since before, various devices and proposal have been made for user to carry out the replacement work of the toner container comfortably. 
   For example, a toner container provided with a self-closing valve at a toner discharging port thereof has been already proposed. Such a toner container can be set up in the apparatus without removing the cap or seal.  FIG. 23  shows an example of the toner container provided with the self-closing valve, which the same applicant as this application has already proposed. 
   Referring to  FIG. 23 , a mouth ring  23 , in which the toner discharging port is formed of the toner container  20 , is provided with a seal valve  60  made of non air-permeable sponge as the self-closing valve. Slits  65 , which intersect each other substantially in the center, are formed in the sealing valve  60 . On the other hand, a nozzle  40 , which serves as an insertion member, is erected in a setting portion  50  in the main body of the apparatus in which the toner container  20  is to be set up. When the toner container  20  is set in the setting portion from above, the nozzle  40  is inserted through the slits  65  in the sealing valve  60 . At this time, the slits  65  in the sealing valve  60  are outstretched so as to make firm contact with an external periphery of the nozzle  40  without any gap. If the toner container  20  is pulled out of the setting portion, the outstretched slits  65  return to their original states by elasticity of the sponge seal  22 . 
   However, the aforementioned toner container  20  has such a problem that toner leaks from the slits  65  in the sealing valve  22 , so that the setting portion  50  is contaminated. Major reasons for such a problem are as follows. 
   The nozzle  40  is not located in the center of the sealing valve  60 . Moreover, when the nozzle  40  is inserted into the sealing valve  60  or removed therefrom, gap is generated between the slits  65  and the nozzle  40 . Moreover, the sealing valve  60  creeps thereby lowering sealing effect. In addition, when the nozzle  40  is pulled out, toner deposited on the nozzle  40  upon setting spills out. 
   SUMMARY OF THE INVENTION 
   It is an object of this invention to provide a developing agent storage container and an image forming apparatus using the same container, capable of reducing toner contamination upon replacement and raising air-tightness of the container. 
   The toner supply unit according to one aspect of this invention comprises: a toner container that holds a toner, the toner container having a toner discharging portion for discharging the toner; a toner container holder that detachably holds the toner container in such a manner that the toner discharging portion faces in a direction of gravity; an insertion member that is inserted into the toner discharging portion while the toner container is held by the toner container holder, wherein toner is filled into the toner container through the insertion member; and a preventing unit for preventing toner contamination due to toner leakage through the self-closing valve, the preventing unit including a self-closing valve, provided to the toner discharging portion, which is opened or closed by removing or inserting the insertion member from/into the toner discharging portion. 
   The toner supply unit according to another aspect of this invention comprises: a toner container that holds a toner, the toner container having a toner discharging portion for discharging the toner; a toner container holder that detachably holds the toner container in such a manner that the toner discharging portion faces in a direction of gravity; an insertion member that is inserted into the toner discharging portion while the toner container is held by the toner container holder, wherein toner is filled into the toner container through the insertion member, the insertion member having a top surface and an opening on the top surface; and a self-closing valve, provided to the toner discharging portion, which is opened or closed by removing or inserting the insertion member from/into the toner discharging portion. 
   The toner supply unit according to still another aspect of this invention comprises: a toner container that holds a toner, the toner container having a toner discharging portion for discharging the toner; a toner container holder that detachably holds the toner container in such a manner that the toner discharging portion faces in a direction of gravity; an insertion member that is inserted into the toner discharging portion while the toner container is held by the toner container holder, wherein toner is filled into the toner container through the insertion member; and a suction unit having an suction port in the vicinity of a toner discharging portion of the toner container held by the toner container holder. 
   The image forming apparatus according to still another aspect of this invention comprises the toner supply unit according to the present invention. 
   Other objects and features of this invention will become apparent from the following description with reference to the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic diagram showing an entire structure of an image forming apparatus of the present invention. 
       FIG. 2  is an explanatory diagram showing an image forming unit of the image forming apparatus of  FIG. 1  in enlargement. 
       FIG. 3  is an explanatory sectional diagram showing an embodiment of a toner supply unit of the present invention. 
       FIG. 4  is an explanatory diagram showing a setting portion of the toner container according to an embodiment of the present invention. 
       FIG. 5  is an explanatory sectional diagram of a setting portion in the toner container shown in FIG.  4 . 
       FIG. 6  is an explanatory diagram for explaining color non-compatibility of the above-described embodiment. 
       FIG. 7  is an explanatory diagram of a nozzle according to other embodiment of the present invention. 
       FIG. 8  is an explanatory sectional diagram of the setting portion using a nozzle of FIG.  7 . 
       FIG. 9  is an explanatory sectional diagram showing a state in which the toner container of  FIG. 8  is set up. 
       FIG. 10  is an explanatory sectional diagram of the toner container according to other embodiment of the present invention. 
     FIG.  11 A and  FIG. 11B  are explanatory diagrams showing a motion of the sealing valve upon removal from/insertion into the toner container. 
       FIG. 12  is an explanatory sectional diagram showing a modification of FIG.  10 . 
       FIG. 13  is an explanatory sectional diagram of the setting portion according to further other embodiment of the present invention. 
       FIG. 14  is an explanatory sectional diagram showing toner container setting time of FIG.  13 . 
       FIG. 15  is an explanatory sectional diagram showing a state in which the set toner container of  FIG. 13  is popped up. 
       FIG. 16  is an explanatory sectional diagram of the setting portion according to further other embodiment of the present invention. 
       FIG. 17  is an explanatory sectional diagram showing an opening/closing valve when the toner container is not set up. 
     FIG.  18 A and  FIG. 18B  are explanatory sectional diagrams showing an opening state and a closing state of the opening/closing valve according to the modification of FIG.  16 . 
       FIG. 19  is an explanatory sectional diagram of the nozzle according to further other embodiment of the present invention. 
       FIG. 20  is an explanatory diagram of the setting portion according to further other embodiment of the present invention. 
       FIG. 21  is an explanatory diagram showing the toner container for preventing buckling of a toner bag. 
       FIG. 22  is a perspective view showing the toner container for preventing buckling of the toner bag. 
       FIG. 23  is an explanatory sectional diagram showing an example of a proposed toner supply unit. 
       FIG. 24  is an explanatory diagram showing a problem in the toner supply unit of FIG.  23 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Embodiment of the present invention will be described in detail with reference to the accompanying drawings. 
     FIG. 1  is a schematic diagram showing a color laser printer which is an example of the image forming apparatus of the present invention. In this color laser printer, a paper feeding portion  2  is disposed at the bottom of an apparatus main body  1  and an image creating portion  3  is disposed above it. The image creating portion  3  includes a transfer belt unit disposed such that it is inclined with its paper supplying side down and its paper discharging side up. The transfer belt unit  8  has an endless transfer belt  8   a,  which is applied on plural belt wheels, that is, belt wheels  4  in this example, and four image creation units  4 M,  4 C,  4 Y,  4 Bk for magenta (M), cyan (C), yellow (Y) and black (Bk) are disposed in parallel on a traveling side above the transfer belt  8   a.    
     FIG. 2  is an explanatory diagram indicating an enlargement of some portion of an image creation unit  4 . As shown in FIG.  1  and  FIG. 2 , the respective image creation units  4 M,  4 C,  4 Y,  4 Bk each includes a photoconductor drum  5  as each of their image carriers. The photoconductor drum  5  is rotated in a clockwise direction by a driving unit not shown. Around the photoconductor drum  5  are provided an electric charging roll  6 , which is an electric charging unit, an optical writing portion which carries out write with laser beam by means of an optical writing unit  7 , a developing unit  10 , which is a developing unit, and a cleaning unit  9 , which is a cleaning unit. The developing unit  10  is a two-component developing unit composed of toner and carrier, to which toner corresponding to an amount of consumed toner is supplied from a toner container  20  by means of a toner supply unit. The toner supply unit supplies toner accommodated in the-toner containers, which are provided in the same quantity as the respective image creation units  4 M,  4 C,  4 Y,  4 Bk. 
   The developing unit  10  is provided with a uni-axial deflection screw pump, which is a suction type powder pump  11 , such that it is disposed in the vicinity or integratedly. The structure of this powder pump  11  is comprised of a rotor  12  formed in the shape of an eccentric screw from material having stiffness such as metal, a stator  13  formed of elastic material such as rubber in the form of a two-row screw and a holder  14  formed of resin material, which wraps these and in which a transportation path for the powder is formed. The aforementioned rotor  12  is rotated by a gear  16  which is connected integratedly to a drive shaft  15  through a pin joint. Meanwhile, reference numeral  17  denotes an electromagnetic clutch, which controls activation of the power pump  11 . 
   A toner suction portion  18  is provided on a front end of the aforementioned holder  14  or on the right end in FIG.  3  and that toner suction portion  18  is connected to a toner connecting port  45  provided on a nozzle  40 , which is an insertion member described later, through a toner transfer tube  19 . This toner transfer tube  19  is of a flexible tube having a diameter of, for example, 4 to 10 mm and if the toner transfer tube is made of rubber material (for example, polyurethane, nitrile, silicone, etc.) having an excellent toner resistance, it is very effective, so that the flexible tube can be placed easily in any direction of upward/downward or to the right or left. The toner supply unit having such a structure is well known to be capable of transferring continuously by a predetermined amount at a high fixed air ratio by means of a uni-axial deflection screw pump, which is the powder pump  11  and secure an accurate transfer amount proportional to the rotation speed of the rotor  12 . If a toner supply instruction is dispatched because of image density detection or the like, the powder pump  11  is actuated, so as to supply a demanded amount of toner to the developing unit  10 . 
   On the other hand, a setting portion  50  provided on the main body  1  of an image forming apparatus, on which the toner container  20  is to be set up, is composed as a separate unit from the developing unit  10 . A nozzle  40  having a circular cross section, which is to be inserted into the toner container  20 , is erected and the toner container  20  is set up in the setting portion  50  of the main body of the image forming apparatus from above. A sharp end member  44  formed to have a conical cross section is provided on a top of the nozzle  40  provided in the setting portion  50  by integral forming or fixing. A path  41 , which serves as an air supply path as well as a toner supply path, is provided following this sharp end member  44 . An interior of the nozzle  40  is of a single pipe structure and the path  41  is bent to the left in the same Figure at a bottom of the nozzle  40  and a toner connecting portion  42 , to which the toner transfer tube  19  is connected, is provided at a front end thereof. Further, air connecting port  43  is provided on the path  41  and bent to the right above the toner connecting port  42 . 
   According to this embodiment, the air connecting port  43  is connected to an air pump  30  which acts as an air supply unit through an air transfer pipe  31 . If this air pump  30  is actuated, air is injected into the toner container  20  through the air transfer pipe  31  and the path  41 . Then, the air injected into the toner container  20  passes through toner layer so as to fluidize the toner by diffusion. 
   The aforementioned toner container  20  is constructed in bag-in-box type comprised of a toner bag  21  which is deformable containing toner and an external box  22  having a higher stiffness than that bag for accommodating the toner bag. The toner bag  21  is formed of resin sheet of polyethylene, nylon or the like or paper sheet of, for example, 80-toner container 20 μm in the form of a single layer or plural layers. The toner bag  21  is formed according to blow formation method and a mouth ring  23  made of resin or the like having a toner discharge mouth is fixed. The mouth ring member  23  is comprised of a circular extended plate  24  provided on an external periphery substantially in the center in vertical direction, a cylindrical portion  25  provided under the extended portion  24  containing a sealing valve  26  inside and a ship-shaped portion  27  provided above the extended portion  24 , on which the toner bag  21  is fixed. The cylindrical portion  25  passes through to the ship-shaped portion  27  so as to form an opening. The sealing valve  60  is provided as a self-closing valve in the opening on the side of the cylindrical portion  25 . The sealing valve  60  is formed of elastic body composed of, for example, non air-permeable foamed sponge or the like. 
   The sealing valve  60  has cross-shaped slits  65 , which intersect each other substantially in the center as shown in FIG.  4  and the slits  65  are closed by elasticity of the sealing valve  60  thereby eliminating a fear that toner is scattered outside. When set in the setting portion  50  of the toner container  20 , the slits  65  in the sealing valve  60  are opened in the axial directions by the nozzle  40 . If it is released from the setting portion  50  of the toner container  20 , the slits  65  are restored in an original state by elasticity so that the toner container  20  is closed. Meanwhile, the shape of the slits  65  is not restricted to cross, however as long as three or more lines are extended radially from the center, it may be employed. In this case, the slits are preferred to be spaced at an equal interval. 
   If the sealing valve  60  made of elastic body such as non air-permeable foamed sponge is used, the nozzle  40  is not located in the center of the sealing valve  60 . If the nozzle  40  is inserted into the sealing valve  60  or pulled out, a gap is generated between the slits  65  and the nozzle  40 , so that the sealing valve  60  creeps thereby reducing sealing effect. Or toner deposited on the nozzle  40  at the time of setting drops out when the nozzle  40  is pulled out, so that toner leaks from the slits  65  in the sealing valve  60 , thereby contaminating the setting portion  50 . Thus, this toner supply unit is provided with a preventing unit for protecting from toner contamination. 
   In  FIG. 4 , a nozzle guide  51  is provided in the setting portion  50  as a guide convex portion in the vicinity of the nozzle  40 . On the other hand, a guide hole  26  is provided in the mouth ring  23  of the toner container  20  as a guide concave portion, which engages the nozzle guide  51 . According to this embodiment, this nozzle guide  51  and the guide hole  26  compose a guide unit for introducing the nozzle  40  to the center of the sealing valve  60 . 
   In the toner supply unit having such a structure, by engaging the nozzle guide  51  with the guide hole  26  when setting the toner container  20 , the toner container  20  is guided to a proper setting position so that the nozzle  40  is inserted into the center of the sealing valve  60 . Thus, it is possible to prevent toner leakage which may be generated unless the nozzle  40  is located in the center of the sealing valve  60 . In this case, by forming the nozzle guide  51  higher than the nozzle  40 , the length L 1  from the nozzle guide  51  to the guide hole  26  in  FIG. 5  can be set shorter than the length L 2  from a front end of the nozzle  40  to the sealing valve. If L 1 &lt;L 2  is set up, when setting the toner container  20 , the nozzle guide  51  having a smaller distance engages the guide hole  26  first and after that, the nozzle  40  is inserted into the slits  65  in the sealing valve  60 . Therefore, the toner container  20  is set at a proper position by the guide unit which engages first, thereby preventing the nozzle  40  from being deflected from the center of the slits  65 . 
   If two or more kinds of toners are used like the aforementioned color image forming apparatus, this toner supply unit can use this system for color non-compatibility. That is, because as shown in  FIG. 6 , the width or position of the nozzle guide  51  can be changed for each toner color accommodated, the position of the guide hole  26  in each color container changes so as to ensure color toner non-compatibility. The reason why, in the example shown in  FIG. 6 , the shapes of the nozzle guides  51  for cyan and black are similar is that the non-compatibility does not have to be ensured by changing the width or position of the nozzle guide  51  because the external boxes  22  of cyan and black are different. 
   FIG.  7  and  FIG. 8  are a perspective view and a sectional view showing other embodiment of the present invention. In this example, a top face of the nozzle  40  is open and an insertion portion  45 , which is to be inserted into the slits  65  in the sealing valve  60  and a compression portion  46  for compressing the sealing valve  60  are provided on a top face thereof. In this case, the compression portion  46  is formed with a flat face rib having an appropriate width on the side of an external periphery of the top face of the nozzle  40  while the insertion portion  45  is formed so as to be erected in the form of a pyramid. 
   When the toner container  20  is set in the setting portion  50 , the sealing valve  60 , which is a sponge, is pressed by the compression portion  46 , so that the nozzle  40  having such a structure  40  is compressed in a vertical direction and consequently, the insertion portion  45  is jumped into the container above the sealing valve  60 . That is, if the diameter of the sealing valve is set larger than that of the compression portion  46  and the compression length is set shorter than the length of the insertion portion  45 , when the sealing valve  60  is compressed, the insertion portion  45  can be jumped above the sealing valve  60 . 
   With this structure, only the insertion portion  45  is inserted into the slits  65  in the sealing valve  60  and even if toner drops out of the slits  65  due to a gap which is generated between the insertion portion  45  and the slits  65  when the toner container  20  is pulled out of the setting portion  50 , that leaking toner drops on the compression portion  46  so that it enters the toner path  41 . Therefore, toner contamination due to toner leakage from the slits  65  can be reduced remarkably. 
     FIG. 10  shows further other embodiment of the present invention. According to this embodiment, the cylindrical portion  25  of the mouth ring  23  is provided with external sealing valve  60  and internal sealing valve  60 A, made of two elastic bodies such as non air-permeable foamed sponge. The external sealing valve  60  is disposed at a bottom on a front end of the cylindrical portion  25  of the mouth ring  23  while the internal sealing valve  60 A is disposed at a top portion within the cylindrical portion  25 , so that space  61  is formed between the external sealing valve  60  and the internal sealing valve  60 A. Then, the aforementioned slits  65  are formed in the external sealing valve  60  and the internal sealing valve  60 A and their external peripheral faces are bonded to an internal wall of the cylindrical portion  25 . 
   In the toner supply unit having such a structure, when with the toner container  20  set up, the nozzle  40  invades into the container, the external sealing valve  60  and the internal sealing valve  60 A are provided with such a freedom that they follow motions of the nozzle  40  as shown in FIG.  11 A. Thus, it is not likely to form a gap between the slits  65  in the external sealing valve  60  and the internal sealing valve  60 A and the nozzle  40 . Further, when taking out the toner container  20  also, the external sealing valve  60  and the internal sealing valve  60 A are so deformed as to follow the motion of the nozzle  60  as shown in FIG.  11 B. Thus, it is not likely to generate a gap between the slits  65  in the external sealing valve  60  and the internal sealing valve  60 A and the nozzle  40 . Therefore, toner leakage from the slits  65 , which occurs when the toner container is mounted or unloaded, can be reduced. 
     FIG. 12  shows a modification of the embodiment of  FIG. 10 , in which a free movable seal  62  made of foamed sponge is provided in space  61  provided between the external sealing valve  60  and the internal sealing valve  60 A. This movable seal  62  is so formed that its outer periphery contacts an internal wall of the cylindrical portion  25  and slits are formed in the center thereof. The thickness of the movable seal  62  is set shorter than the width in a vertical direction thereof. Therefore, the movable seal  62  is so constructed as to be capable of moving vertically within the width of the space  61 . 
     FIG. 13  is a sectional view showing part of the setting portion  50  according to further other embodiment of the present invention. 
   Referring to  FIG. 13 , a preventing unit  70 , which engages the nozzle  40  movably, is provided as a unit for preventing toner contamination. The preventing unit  70  comprises a seal  71  made of elastic body such as sponge provided on a face opposing the toner container  20 , a supporting frame  72  for supporting the seal  71  and a spring  73 , which is an elastic unit for applying a upward pressing force to the supporting frame. The seal  71  has slits  74  in the center thereof and is fixed to a supporting frame  72  by bonding or the like. The supporting frame  72  is a member having a concave cross section, having with a jaw portion  75  on an external periphery of the top portion thereof. A hole  76 , to which the nozzle is fit movably, is provided in the center of the concave portion  40  nd the depth of the concave portion in the supporting frame  72  is set larger than the thickness of the seal  71 . 
   The aforementioned spring  73  is a coil spring mounted between a machine frame  52  of the setting portion  50  and the supporting frame  72  so as to press the jaw portion  75  of the supporting frame  72 . When the toner container  20  is not set up, the spring  73  holds the aforementioned supporting frame  72  at the highest position shown in FIG.  13 . The length and strength of the spring  73  are set up so that the nozzle  40  does not slip out of the hole  76  in the supporting frame  72  at this time. Meanwhile, top and bottom ends of the spring  73  are preferred to be fixed to the supporting frame  72  and the machine frame  52  by bonding. 
   In the toner supply unit having such a structure, when the toner container  20  is set in the setting portion  50 , as shown in  FIG. 14 , the supporting frame  72  is pressed against the mouth ring  23  of the container and with the nozzle  40  engaged, moves downward resisting a upward pressing force of the spring  73 , so that a front end of the nozzle  40  is inserted into the container. At this time, the cylindrical portion  25  of the mouth ring  23  engages the concave portion in the supporting frame  72 , so that the sealing valve  60  make firm contact with the seal  71 . Because at this time, the spring  73  always applies upward elastic force to the toner container  20  through the supporting frame  72 , a stopper unit (not shown) for holding the toner container  20  at the setting position is provided. As this stopper unit, an engaging pawl or the like for making engagement at the top of the toner container  20  is effective. 
   Next, if the toner container  20  is taken out of the setting portion  50 , as shown in  FIG. 15 , the supporting frame  72  is pressed up to a position where the sealing valve  60  of the toner container is closed, by the spring  73  and then, the supporting frame  72  follows the motion of the toner container  20 . Therefore, even if the sealing valve  60  does react immediately when the nozzle  40  slips out and is not closed soon, so that toner leakage occurs, the leaking toner can be received by the seal  71 . Thus, it is possible to avoid contamination of the setting portion  50  with scattered toner. 
   Because the spring  73  applies an action for raising the toner container  20 , the toner container  20  can be brought up by a specific amount by using the spring force. That is, because the toner container  20  is held at the setting position such that the engaging pawl or the like engages as described above, when taking out the toner container  20 , this container is brought up by means of the spring  73  by releasing this engaging pawl or the like. Thus, the operability upon taking out the toner container  20  can be improved by constructing this toner container  20  to be popped up. Further, because the mouth ring  23  of the toner container  20  is pressed against the jaw portion  75  of the supporting frame  72 , it receives a stabilized upward pushing action. 
     FIG. 16  is a sectional view of the setting portion  50  showing further other embodiment of the present invention. 
   Referring to  FIG. 16 , the toner container  20  is provided with an opening/closing valve  80 , which is opened/closed by the nozzle  40  and the aforementioned sealing valve  60  as a unit for preventing toner contamination. The opening/closing valve  80  includes a valve body  81  which is opened/closed by mounting or unloading the nozzle  40 , a valve seat  82  on which that valve body is settled, and an elastic rubber  83  as an elastic member for applying elastic force to the valve body  81  in a direction that it always rests on the valve seat  82 . In this opening/closing valve  80 , the valve seat  82  is supported directly by the mouth ring  23 , while the valve body  81  and the elastic rubber  83  are supported by the mouth ring  23  via the bracket  28 . A hole  84 , which the nozzle  40  passes through, is formed in the valve seat  82  and when the container is not set up, as shown in  FIG. 17 , the valve body  81  rests on the valve seat  82  such that it closed this hole  84  from above. Further, the sealing valve  60  is made of elastic foamed body such as sponge and the cross-shaped slits  65  are formed in the center thereof. Meanwhile, the elastic member is not restricted to the elastic rubber  83 , but may be formed of resin or the like having a restoration force. 
   In the toner supply unit having such a structure, if the toner container  20  is set up in the setting portion  50 , the slits  65  in the sealing valve  60  are pushed wide in the axial directions by the nozzle  40  and further, the nozzle  40  passes through the valve seat  82 , so that it raises the valve body  81  resisting an action of the elastic rubber  83 , and then, the nozzle  40  is inserted until the opening portion  40   a  invades into the container. If the toner container  20  is taken out, the valve body  81  rests on the valve seat  82  due to a restoration force of the elastic rubber  83 , so as to shut down between inside and outside of the container thereby ensuring air tightness. In the same way, the sealing valve  60  is restored to its own original state due to the self-restoration force. At this time, if viewed from the side of the nozzle  40 , the sealing valve  60  moves upward with the nozzle  40  in firm contact therewith, so that the slits  65  close gradually. As a result, this not only prevents toner from dropping from the nozzle but also provided an effect of cleaning the nozzle  40 . 
   If only the sealing valve  60  is provided, the toner container  20  can be provided with some extent of air tightness and however, when it is loaded or unloaded, toner leaks through a gap between the nozzle  40  and the valve seat  82 . Thus, in this case, it is difficult to prevent toner scattering. Even if this leakage is intended to be suppressed by controlling an engagement tolerance in dimension between the nozzle  40  and the hole  84  of the valve seat  82  strictly in order to suppress the leakage, toner which is fine powder penetrates into the gap, adheres due to electrostatic force by friction or van del Waals force, unlike liquid. Thus, there is a possibility that the nozzle  40  and the valve seat  82  may be locked so that they do not move. Further, if the tolerance is set strictly, a setting force of the container increases. Therefore, because if such elastic body as rubber, fine cell sponge is used for the valve seat  82 , a force in the diameter direction is released by that elasticity, air-tightness can be obtained without increasing the setting force. 
   Further, if only the sealing valve  60  is employed, there is a possibility that the elastic body may undergo creep deformation due to leaving for a long period, so that an excellent air-tightness in the container cannot be secured. Therefore, by providing the opening/closing valve  80  with a function for securing air-tightness of the container like the above described embodiment and further providing the sealing valve  60  with cleaning function for reducing toner scattering, the toner leakage from the toner container  20  and the toner scattering upon loading/unloading can be reduced at the same time. 
   FIG.  18 A and  FIG. 18B  show a modification of the embodiment shown in  FIG. 16 , in which a coil spring  85  is used as the elastic member of the opening/closing valve  80 . If resin or rubber is employed as the elastic member, its restoration force may drop because of creep deformation generated by repeated use or leaving for a long period thereby leading to reduction in the air-tightness of the container. Thus, if the coil spring  85  is used, the deterioration due to repeated use never occurs, so that the air-tightness of the container can be secured. 
   Although as described above, toner contamination, which is generated by toner leakage from the sealing valve  60  can be prevented according to the present invention, it is difficult to eliminate the leakage of toner which is fine powder completely. Particularly, even if the toner leakage can be reduced in such an unfavorable situation where the toner container  20  is inserted or removed repeatedly or left for a long period, this cannot be reduced to zero. 
   According to the embodiment shown in  FIG. 19 , a top end of the nozzle  40  is provided with an opening  40   a  so as to catch up toner cleaned by the sealing valve  60  or toner leaking from the slits  65 . Then, by constructing the opening  40   a  as an opening for toner receiving for the toner path  41  connected to the developing unit  10 , caught up toner can be consumed without waste. 
   With such a structure, it is possible to reduce the possibility that toner cleaned by the sealing valve  60  or toner leaking from the slits  65  may be scattered so as to contaminate the setting portion  50  and the toner container  20 . 
   According to the embodiment shown in  FIG. 20 , a suction port  32  of the air pump  30  which supplies air into the inside of the toner container  20  is disposed in the vicinity of the nozzle of the setting portion  50 . 
   With such a structure, even if toner leaks from the sealing valve  60  in the toner container  20 , the toner can be sucked and cleaned by an activation of the air pump  30 . Thus, contamination of the setting portion  50  and the toner container  20  by leaking toner is reduced to a large extent. 
   The toner container  20  described in the above embodiment is comprised of the flexible toner bag  21  and the external box  22  having stiffness for covering it. Then, the toner bag  21  is formed such that its sectional area decreases as it goes to the mouth ring  23  having a toner discharging portion. 
   However, under such a structure, if the toner container  20  receives any impact, the toner bag  21  may be sometimes buckled at that squeezing portion. Particularly, because the toner bag  21  is softened under high temperatures, it is likely to be buckled. 
   As shown in  FIG. 21 , in order to prevent such buckling, a supporting plate  90  for supporting the squeezing portion of the toner bag  21  is provided. This supporting plate  90  is mounted on the external box  22  not shown in FIG.  21 . 
   Further, to prevent the aforementioned buckling, a top plate  91  is fixed on top of the toner bag  21  and then, this top plate is loaded in a slide guide portion  92  formed in the external box  22  by sliding as shown in FIG.  22 . 
   Embodiments of the present invention have been described above. However, the present invention is not restricted to the above described embodiments, however may be modified in various ways. 
   For example, the insertion member is preferred to be a nozzle having a circular cross section, and however, the shape of the nozzle is not restricted to circular, but may be elliptic, polygon or the like. However, if it is polygon, it is preferred to be of regular polygon with its corners rounded. 
   As explained above, according to the present invention, when the self-closing valve made of foamed elastic body facilitating removal or insertion of the insertion member of the toner container is provided, leakage of toner from the self-closing valve can be reduced to a large extent. 
   Furthermore, the insertion member can be inserted into the center of the slits in the self-closing valve, so that toner leakage which is generated when the insertion position of the insertion member deflects can be prevented. 
   Moreover, the insertion member can be inserted securely into the center of the slits in the self-closing valve. 
   Furthermore, the unit for guiding the insertion member to be inserted into the center of the slits in the self-closing valve can be provided with color non-compatible function. 
   Moreover, toner leakage from the self-closing valve of the toner container can be reduced to a large extent. 
   Furthermore, toner leaking from the self-closing valve can be introduced into the toner path. 
   Moreover, air-tightness between the insertion member and the self-closing valve is intensified, so that toner leakage from the self-closing valve can be reduced to a large extent. 
   Furthermore, toner leakage from the self-closing valve can be reduced and further, even if toner leaks, scattering thereof can be prevented securely. 
   Moreover, because the toner container is pushed by the jaw portion having a width, the container can be raised upward stably. 
   Furthermore, the opening/closing valve can be provided with a function for securing air-tightness of the container and further, the sealing valve of foamed elastic body can be provided with a cleaning function for reducing scattering of toner. 
   Moreover, the air-tightness of the toner container can be intensified by improving the closing state of the opening/closing valve. 
   Furthermore, such deterioration in setting operability that a large force is required when setting the toner container can be prevented. 
   Moreover, even if toner leaks from the self-closing valve of the toner container, most of the toner can be introduced to the toner path in the insertion member. 
   Furthermore, even if toner leaks from the self-closing valve of the toner container, that toner can be cleaned. 
   Moreover, the aforementioned cleaning action can be obtained from an air pump for supplying air to the toner container. 
   The present document incorporates by reference the entire contents of Japanese priority document, 2000-297354 filed in Japan on Sep. 28, 2000. 
   Although the invention has been described with respect to a specific embodiment for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art which fairly fall within the basic teaching herein set forth.