Abstract:
A developer container including: a container body for containing a developer, the container body being formed by a bottom wall, two side walls, a first end wall, and a second end wall, the first end wall being provided with an opening for feeding the developer; and a member connecting the first end wall and the second end wall to prevent a deformation of an attachment surface for a toner seal member.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention relates to a developer container usable in an electrophotographic image forming apparatus, a process cartridge, and an electrophotographic image forming apparatus.  
           [0003]    Here, the electrophotographic image forming apparatus forms an image on a recording medium by the use of the electophotographic image forming process. The examples of the electrophotographic image forming apparatus include, for example, an electrophotographic copier, an electrophotographic printer (such as a laser beam printer or an LED printer), a facsimile apparatus, and a word processor.  
           [0004]    The aforementioned process cartridge may refer to charging means, developing means or cleaning means and an electrophotographic photosensitive member integrally made into a cartridge, which is made detachably mounted to the main body of the electrophotographic image forming apparatus. Alternatively, the process cartridge may refer to at least one of charging means, developing means, and cleaning means and an electrophotographic photosensitive member integrally made into a cartridge, which is made detachably mountable to the main body of the electrophotographic image forming apparatus. Further alternatively, the process cartridge may refer to at least developing means and an electrophotographic photosensitive member integrally made into a cartridge, which is made detachably mountable to the main body of the electrophotographic image forming apparatus.  
           [0005]    2. Description of Related Art  
           [0006]    In an electrophotographic image forming apparatus using the electrophotographic image forming process, there has heretofore been adopted a process cartridge system in which an electrophotographic photosensitive member and process means for acting on the electrophotographic photosensitive member are integrally made into a cartridge which is made detachably mountable to the main body of the image forming apparatus. According to the process cartridge system, the maintenance of the apparatus can be done by a user himself without resort to a serviceman and therefore, the operability of the apparatus be markedly improved. So, this process cartridge system is widely used in electrophotographic image forming apparatuses.  
           [0007]    As shown in FIG. 12 of the accompanying drawings, a process cartridge  45  according to the prior art comprises a developing frame  43  supporting a developing member such as a developing roller  48  and a toner container  46  ultrasonically welded together to form a developing unit. A photosensitive drum  44 , a charging roller  41  and a cleaning frame  47  constituting a removed toner container are connected together by a shaft  49 . A compression coil spring  42  is provided between the cleaning frame  47  and the developing frame  43  to thereby bias the photosensitive drum  44  and the developing roller  48  toward each other.  
           [0008]    An electrophotographic image forming apparatus using such a process cartridge is in the tendency toward the larger capacity of the toner container and the larger size of the removed toner container to lengthen the service lift of the process cartridge until interchanged.  
           [0009]    However, when the toner container is made larger in capacity, the weight of a toner increases with a result that when the developer is increased in quantity by the use of the prior art, a load applied to the developing roller and the photosensitive drum increases. Also, as the developer is consumed, the load is changed.  
           [0010]    In order to solve this problem, a flexible sheet member is stuck on between the toner container and a developing container. A method of hermetically sealing the space between the two containers to thereby reduce the weight of a toner containing frame being applied to the developing container is under consideration.  
         SUMMARY OF THE INVENTION  
         [0011]    It is an object of the present invention to provide a developer container, a process cartridge, and an electrophotographic image forming apparatus in which the strength of an opening portion can be enhanced.  
           [0012]    It is another object of the present invention to provide a developer container, a process cartridge and an electrophotographic image forming apparatus in which the deformation of an opening portion can be prevented.  
           [0013]    It is another object of the present invention to provide a developer container in which a developing frame is not welded and a developer supply opening portion is sealed by a toner seal member and the deformation of the stuck surface of the toner seal member does not occur, and a process cartridge having the developer container, and an electrophotographic image forming apparatus, to which the process cartridge is detachably mountable.  
           [0014]    It is another object of the present invention to provide a developer container containing a developer therein and having an opening portion sealed by a toner seal member and adapted to be unsealed during use to supply a developer to developing means, and provided with a bridge-shaped portion extending from the back side of the surface of the opening portion side for supplying the developer and connected to the other end surface opposed to the surface substantially in parallelism thereto.  
           [0015]    It is another object of the present invention to provide a process cartridge detachably mountable to an image forming apparatus, the process cartridge comprising an electrophotographic photosensitive member, developing means for visualizing an electrostatic latent image formed on the electrophotographic photosensitive member, a developing frame supporting the developing means and having an opening portion for receiving a developer therein, a developer container displaceable relative to the developing frame and containing the developer therein and having an opening portion for supplying the developer to the developing means, and provided with a bridge-shaped portion extending from the back side of the surface of the opening portion side for supplying the developer and connected to the other end surface opposed to the surface substantially in parallelism thereto, and a toner seal member for unsealably sealing the opening portion.  
           [0016]    It is another object of the present invention to provide an electrophotographic image forming apparatus, to which a process cartridge is detachably mountable for forming an image on a recording medium, the electrophotographic image forming apparatus comprising:  
           [0017]    (a) mounting means for detachably mounting a process cartridge comprising an electrophotographic photosensitive member, developing means for visualizing an electrostatic latent image formed on the electrophotographic photosensitive member by a developer, a developing frame supporting the developing means and having an opening portion for receiving the developer therein, a developer container displaceable relative to the developing frame and containing the developer therein and having an opening portion for supplying the developer to the developing means, and provided with a bridge-shaped portion extending from the back side of the surface of the opening portion side for supplying the developer and connected to the other end surface opposed to the surface substantially in parallelism thereto, and a toner seal member for unsealably sealing the opening portion; and  
           [0018]    (b) transporting means for transporting the recording medium.  
           [0019]    These and other objects, features and advantages of the present invention will become more apparent upon consideration of the following description of the preferred embodiment of the present invention taken in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]    [0020]FIG. 1 is a vertical cross-sectional view of an image forming apparatus.  
         [0021]    [0021]FIG. 2 is a main cross-sectional schematic view of a process cartridge in an embodiment of the present invention.  
         [0022]    [0022]FIG. 3 is an exploded perspective view of the process cartridge in the embodiment of the present invention.  
         [0023]    [0023]FIG. 4 is a perspective view of a seal member in he embodiment of the present invention.  
         [0024]    [0024]FIG. 5 is a perspective view of the seal member in the embodiment of the present invention.  
         [0025]    [0025]FIG. 6 is a side view of the process cartridge in the embodiment of the present invention.  
         [0026]    [0026]FIG. 7 is a side view of the process cartridge in the embodiment of the present invention.  
         [0027]    [0027]FIG. 8 is a front view of the toner discharge opening portion of a toner container in the embodiment of the present invention.  
         [0028]    [0028]FIG. 9 is a cross-sectional view of a toner seal member in the embodiment of the present invention.  
         [0029]    [0029]FIG. 10 is a vertical cross-sectional view of a toner containing unit in the embodiment of the present invention before it is welded.  
         [0030]    [0030]FIG. 11 is a vertical cross-sectional view of the toner containing unit in the embodiment of the present invention after it is welded.  
         [0031]    [0031]FIG. 12 is a main cross-sectional schematic view of a process cartridge according to the prior art. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0032]    An embodiment of the present invention will hereinafter be described with reference to FIGS.  1  to  11 . The lengthwise direction in the embodiment refers to a direction perpendicular to the transporting direction of a recording medium and parallel to the surface of the recording medium.  
         [0033]    (Description of a Process Cartridge and the Main Body of an Apparatus)  
         [0034]    [0034]FIG. 1 is a main cross-sectional view of an image forming apparatus according to the present invention, and FIG. 2 is a main cross-sectional view of a process cartridge according to the present invention. The process cartridge is provided with an image bearing member and process means for acting on the image bearing member. The process means include, for example, charging means for charging the surface of the image bearing member, a developing device for forming a toner image on the image bearing member, and cleaning means for removing any toner residual on the surface of the image bearing member. The process cartridge can be provided with the image bearing member and at least one of the process means.  
         [0035]    The process cartridge  15  in the present embodiment, as shown in FIG. 2, comprises an electrophotographic photosensitive drum (hereinafter referred to as the photosensitive drum)  11  which is an image bearing member, a charging roller  12  which is charging means arranged around the photosensitive drum  11 , a cleaning frame  13  containing therein a cleaning blade  14  as cleaning means, a drum protecting shutter  9  for protecting the photosensitive drum  11 , a developing frame  17  containing therein a developing roller  18  and a developing blade  26  as a developing device, and a toner containing unit  16  for containing therein a toner which is a developer. The toner containing unit  16  is constituted by a toner container  30  and a toner containing lid  31 . The toner container  30  contains agitating members  34 ,  35  and  36  as rotary members for agitating the toner. The toner container  30  and the toner containing lid  31  are welded together to form the toner containing unit  16 . And these are integrally made into the process cartridge  15  which is made detachably mountable to the main body of the image forming apparatus without any unreasonable force being applied to the process means by holding a handle  10  provided on the upper portion of the toner containing lid  31 .  
         [0036]    The process cartridge  15  is mounted to the image forming apparatus as shown in FIG. 1 and is used for image formation. Image formation is effected on a sheet S as a recording medium transported from sheet cassettes  6  mounted on the lower portion of the apparatus to the transferring position of the photosensitive drum  11  by transporting rollers  7 .  
         [0037]    The photosensitive drum  11  is charged by the charging roller  12 , whereafter it is subjected to selective exposure in conformity with image information by an exposing device  8 , whereby an electrostatic latent image is formed thereon. The exposure is effected in synchronism with the transportation of the sheet by registration rollers  3 .  
         [0038]    Thereafter, the toner contained in the toner containing unit  16  is fed to the developing frame  17  side, and the toner is applied as a thin layer onto the surface of the developing roller  18  by the developing blade  26 , and a developing bias voltage is applied to the developing roller  18 , whereby the toner is supplied from the developing roller  18  to the photosensitive drum  11  in conformity with the latent image. A toner image thus formed on the photosensitive drum  11  is transferred to the sheet S being transported by the application of a bias voltage to a transferring roller  5  at a transferring position, and the sheet S is transported to a fixing device  4 , whereby the toner image is fixed, and the sheet S is delivered to a delivery portion  2  in the upper portion of the apparatus by delivery rollers  1 . On the other hand, any toner residual on the photosensitive drum  11  after the transfer of the toner image is removed by the cleaning blade  14  and is stored in the cleaning frame  13 .  
         [0039]    (Frame Construction of the Process Cartridge)  
         [0040]    The surrounding portions of the developing device will be further described in detail.  
         [0041]    [0041]FIGS. 2 and 3 schematically show the construction of the process cartridge  15  in the present embodiment. The developing device D in the process cartridge  15  is such that the toner contained in the toner containing unit  16  is borne on the surface of the developing roller  18  as a toner bearing member and also, a developing bias voltage is applied to the developing roller  18  to thereby supply the toner in conformity with the latent image formed on the photosensitive drum  11 .  
         [0042]    The developing roller  18  is comprised of a cylindrical metal such as aluminum or stainless steel and contains a magnet roller  18   a  therein.  
         [0043]    [0043]FIG. 3 is a typical exploded view showing the construction of the process cartridge. The toner containing unit  16  is positioned by the bosses  19   c  of side covers  19  and  20  being fitted onto the positioning pins  30   a  of the toner container  30 , and is fixed to the side covers  19  and  20  in position. Also, the cleaning frame  13  rotatably supports the photosensitive drum  11  through a bearing pin  50  and a bearing  51 . The cleaning frame  13 , similarly to the toner containing unit  16 , is fixed to the side cover  19  by a positioning boss  13   b  being fitted onto a positioning pin  19   b  and by the bearing pin  50  fixed to the cleaning frame  13  being fitted into a hole  19   a  in the side cover  19 . The positioning of the side cover  20  and the cleaning frame  13  is similar to that on the side cover  19  side. Thus, the cleaning frame  13  and the toner containing unit  16  are integrally fixed through the side covers  19  and  20 .  
         [0044]    Also, as shown in FIG. 2, the developing frame  17  of the developing device D supports developing members, such as the developing roller  18  and the developing blade  26  and is swingably supported in the hanging hole  13   d  of the cleaning frame  13  by a pin so as to be rotatable about the hanging hole  13   d . As shown in FIG. 6 in which the side cover  20  is removed, a tension coil spring  22  is extended between a spring hook  13   c  projectedly provided on the cleaning frame  13  and a spring hook  17   f  projectedly provided on the developing frame  17 .  
         [0045]    Also, a compression coil spring  27  (FIG. 7) is disposed in the interior of the side cover  19  so as to press a developing roller bearing  17   e . The developing roller bearing  17   e  is movably fitted in a slot  19   e  in the side cover  19 . The slot  19   e  extends in a radial direction of the photosensitive drum  11 . By the spring forces of the compression coil spring  27  and the tension coil spring  22 , abutment runners  18   b  having a radius as large as a developing gap (about 300 μm) and provided on the opposite end portions of the developing roller  18  concentrically therewith are brought into pressure contact with the outside of the image area of the photosensitive drum  11 .  
         [0046]    Design is made such that a gap is formed between the developing frame  17  and the toner container  30 . Further, the toner container  30  is designed such that the lower side of the surface thereof opposed to the developing frame  17  is along a substantially horizontal line.  
         [0047]    In the present embodiment, the gap between the developing device D and the toner container  30  is designed to be sealed, and as a seal member, a sheet member is stuck and formed into a bellows shape to thereby seal the gap, and the seal member is attached through a plate member. In this case, the sheet member has a thickness of 1 mm or less, but may have a thickness of 1 mm or greater by selecting a material which will not spoil the flexibility of the aforementioned bellows shape.  
         [0048]    [0048]FIGS. 4 and 5 schematically show a method of forming a bag-shaped seal member by the sheet member.  
         [0049]    As shown in FIG. 4, the sheet member  21  has opening portions  21   a  and  21   b  substantially equal to or greater in area than the opening portion  23   b  of a plate-shaped member  23  and the opening portion  17   b  of the developing frame  17 . The sheet member  21  is joined to the plate-shaped member  23  and the developing frame  17  in a closed shape (hatched portions) in the vicinity of the opening portions  23   b  and  17   b.    
         [0050]    In the case of the present embodiment, the joint of the developing frame  17  and the plate-shaped member  23  with the sheet member  21  is effected by heat welding such as the heat sealing method or the impulse sealing method, but use may also be made of ultrasonic welding, an adhesive agent, an adhesive tape or the like.  
         [0051]    Next, as shown in FIG. 5, the sheet member  21  is stuck on the developing frame  17  and the plate-shaped member  23 , and thereafter is folded in the direction indicated by the arrow so that the both opening portions thereof may face each other to thereby form a bellows (a bag shape), and the end portions  21   d  (hatched portions) of the surfaces thereof turned back and facing each other are joined together and sealed. As sealing means in this case, use can also be made of heat welding such as the heat sealing method or the impulse sealing method, or ultrasonic welding, an adhesive agent or an adhesive tape.  
         [0052]    Next, the plate-shaped member  23  is attached to the toner container  30 , but at this time, a portion of the attached portion is not welded or adhesively secured so as to permit a toner seal member  24  to pass therethrough.  
         [0053]    In the case of the present embodiment, design is made such that a portion  23   a  shown in FIG. 3 is welded and an area in which a toner sealing member  25  holds down the toner seal member  24  is not welded or adhesively secured.  
         [0054]    By doing so, even if the spacing between the opposed surfaces of the toner container  30  and the developing frame  17  fluctuates, the sealing member  21  completed by the use of the sheet member  21  (the same reference numeral  21  being used for the sheet member and the sealing member in its completed state) keeps the shape of a bag-shaped bellows and therefore, the resistance when displacement occurs can be made very small. Also, by the sealing member  21  being attached between the plate-shaped member  23  and the developing frame  17 , the plate-shaped member  23  can be attached so as to cover the toner seal member  24 , and it becomes possible to mount the toner sealing member  25  in the gap through which the toner seal member  24  passes, and the leakage of the toner can be prevented.  
         [0055]    Further, when the plate-shaped member  23  and the developing frame  17  are to be sealed in the same plane, as compared with a case where the sheet member is directly stuck on the toner container  30 , the shape of a welding receiving stand necessary for welding can be simplified.  
         [0056]    Further, owing to the presence of the plate-shaped member  23 , it becomes possible to make the developing frame  17  into a unit, and the attachment of the sealing member  21  to the toner containing unit  16  becomes easy.  
         [0057]    (Mounting and Dismounting of the Process Cartridge to and from the Main Body of the Apparatus)  
         [0058]    [0058]FIG. 1 shows a state in which the process cartridge  15  can effect image formation. To detach the process cartridge  15  from the state of FIG. 1, an operating lever (not shown) provided on the front face of the main body of the apparatus is pivotally moved, whereupon a pivotable arm  6  is pivotally moved in the direction indicated by the arrow A, and the left side of the process cartridge  15  as viewed in FIG. 1 is raised by the tip end of the arm  6 . Thereupon, the left side of the process cartridge  15  is upwardly and pivotally moved about a fulcrum  15   b  on a guide rail  107 , whereby a guide portion  15   a  present only on the inner part side of the process cartridge  15  is aligned with the guide rail  28  of the main body of the apparatus. When in this state, the process cartridge  15  is pulled in the direction of this side orthogonal to the plane of the drawing sheet of FIG. 1, the guide portion  15   a  shifts to the guide rail  28  and subsequently, the support of the process cartridge  15  by the arm  6  is released. When the process cartridge  15  is intactly drawn out, it can be drawn out of the main body of the apparatus.  
         [0059]    To mount the process cartridge  15  to the main body of the apparatus, an operation converse to what has been described above can be performed, that is, with the guide portion  15   a  and the fulcrum  15   b  aligned with the guide rails  28  and  107 , respectively, the process cartridge  15  is inserted into the inner part side orthogonal to the plane of the drawing sheet of FIG. 1. Thereupon, before the guide portion  15   a  comes out of engagement with the guide rail  28 , the left upper portion of the process cartridge  15  is supported by the arm  6 , and when the process cartridge  15  is further pushed in, the guide portion  15   a  comes out of engagement with the guide rail  28 . Here, a lock (not shown) locking the arm  6  is released and by means of the aforementioned operating lever (not shown) provided on this side of the main body of the apparatus, the arm  6  is pivotally moved in the direction opposite to the direction indicated by the arrow A. The gravity of the process cartridge  15  is added to this pivotal movement.  
         [0060]    When the process cartridge  15  comes close to a position capable of forming an image, a bearing pin  50  outwardly protruding from a hole  19   a  in the side cover  19  shown in FIG. 3 (this also holds true of the side cover  20  side) fits in the positioning recess (not shown) of the main body of the apparatus and is positioned. Thereby the position of the photosensitive drum  11  is accurately decided relative to the main body of the apparatus because the photosensitive drum  11  and the bearing pin  50  are coaxial with each other. The mounting and dismounting of such a process cartridge  15  with respect to the main body of the apparatus are good even if the toner container  30  contains a great amount of toner therein and is heavy. The process cartridge  15  has, besides the handle  10  on the upper portion thereof, a handle (not shown) on this side in the mounting and dismounting direction, and satisfies the carrying thereof or the operability at the beginning of the mounting and the end of the dismounting thereof from the main body of the apparatus.  
         [0061]    (Description of the Toner Containing Unit)  
         [0062]    The toner containing unit  16  will now be described with reference to FIGS.  8  to  11 . The toner containing unit  16  is comprised of the toner container  30 , the toner containing lid  31  and the agitating members  34 ,  35 ,  36 . The toner container  30  is provided with an opening portion  32  for feeding the toner therethrough to the developing frame  17 . The opening portion  32  is covered with the toner seal member  24 . The toner seal member  24  is heat-welded to the toner container  30  around the opening portion  32  by a welding portion  50  (hatched portion) so as to cover the opening portion  32  (see FIG. 8).  
         [0063]    The toner seal member  24  is folded back in the lengthwise direction of the opening portion  32  (the same direction as the lengthwise direction of the photosensitive drum  11 ) and is superposed on a portion covering the opening portion  32 , and has its end portion drawn out of the cartridge frame (side cover  20 ) as shown in FIG. 3.  
         [0064]    The toner seal member  24  used in the present embodiment is of a layer construction comprising, in succession from the surface layer,  
         [0065]    polyester of 12 μm (strength maintaining layer,  24   i  in FIG. 9),  
         [0066]    aluminum foil of 7 μm (laser intercepting layer,  24   j  in FIG. 9),  
         [0067]    polyester of 50 μm (tear guide layer,  24   k  in FIG. 9), and  
         [0068]    a sealant layer 50 μm (container adhesive layer,  24   l  in FIG. 9).  
         [0069]    A tear portion  24   e  (see FIG. 8) for unsealing is subjected to the laser cutting process by which a carbon dioxide laser is applied from a sealant layer side and a part of a polyester layer which is a tear guide layer  24   k  and a sealant layer ( 24   l ) is melted, whereby a cavity portion  24   h  is formed (FIG. 9 is a cross-sectional view of the seal member and shows the cavity portion  24   h  by laser working). An aluminum foil layer  24   j  intercepts the laser and therefore, the outermost polyester layer ( 24   i ) is not injured, but can secure a sufficient sealing property. During unsealing, stress concentrates in the cavity portion  24   h  formed by the laser working process and therefore, the toner seal member can be positively torn and unsealed along the tear portion  24   e.    
         [0070]    Also, in the toner container  30 , there are provided the agitating members  34 ,  35  and  36  for feeding the toner from the opening portion  32  to the developing frame  17  and agitating the toner. The agitating members  34 ,  35  and  36  comprise flexible sheet members  34   a ,  35   a  and  36   a  fixed to agitating bars  34   c ,  35   c  and  36   c , respectively, by sheet holding members  34   b ,  35   b  and  36   b . In the present embodiment, as the sheet member  34   a , use is made of a sheet member of PPS material having a thickness of about 50 μm, and as each of the sheet members  35   a  and  36   a , use is made of a sheet member of PPS having a thickness of about 100 μm. Also, the agitating members  34 ,  35  and  36  are all rotated in the same direction (clockwise direction in FIG. 2), and the agitating member  34  nearest to the developing frame  17  is rotated at about 20 rpm and the remaining agitating members  35  and  36  are rotated at about 5 rpm.  
         [0071]    The bottom surface of the toner container  30  assumes the cross-sections of semicircular portions  30   c ,  30   d  and  30   e . This is because by the bottom surface of the toner container  30  being made semicircular and the radius of rotation of the agitating members  34 ,  35  and  36  being made larger than the radius of the bottom surface, it becomes possible for the sheet members to agitate the toner while rubbing against the bottom surface and even when the consumption of the toner has progressed and the amount of the toner has become small, the toner on the bottom surface can be scraped off and fed to the developing frame  17  and it becomes possible to decrease the amount of remaining toner. In the present embodiment, the inroad amount of the sheet members  34   a ,  35   a  and  36   a  into the semicircular portions  30   c ,  30   d  and  30   e , respectively, is 2-4 mm.  
         [0072]    The toner container  30  has the other end surface  30   k  substantially in parallel to the back side  30   i  of a surface  30   h  to which the plate-shaped member  23  is attached.  
         [0073]    In the toner container  30 , there is provided a bridge-shaped rib  30   b  extending from the back side  30   i  of the surface  30   h  of the toner discharging opening portion  32  to which the plate-shaped member  23  is attached to the other end surface  30   k  of the toner container  30 . The bridge-shaped rib  30   b  has its lower edge rising upwardly by an inclined surface  30   j  from the upper back side edge of the opening portion  32  to a position at which it is not a hindrance when the agitating member  34  is incorporated into the toner container  30 , and thereafter is connected to the other end surface  30   k  of the toner container  30  so as not to interfere with the toner agitating members  34 ,  35  and  36 , and continues to the other end surface  30   k  by an arc  30   m . The bridge-shaped rib  30   b  is provided in the substantially central portion of the toner container  30  in the lengthwise direction thereof (a direction orthogonal to the plane of the drawing sheet of FIG. 10). The cross-section of the bridge-shaped rib  30   b  which is formed as a bridge-shaped portion is of a plate shape of which the plate surface is vertical, but the cross-sectional shape thereof may be other shape such as T-shape, I-shape, H-shape, a circle or U-shape.  
         [0074]    Also, on that side of the toner containing lid  31  which is adjacent to the toner container, intercepting ribs  31   a  and  31   b  are provided toward the lengthwise direction at locations substantially aligned with the convex portions  30   f  and  30   g  of the bottom surface of the toner container  30 . The intercepting ribs  31   a  and  31   b  are cut away at the central portions  31   c  thereof so as not to interfere with the bridge-shaped rib  30   b  in the toner container  30  (see FIG. 3).  
         [0075]    After the agitating members  34 ,  35  and  36  have been incorporated into the toner container  30 , the toner containing lid  31  and the toner container  30  are welded together to thereby form the toner containing unit  16 . At this time, the gaps  37  and  38  between the intercepting ribs  31   a ,  31   b  and the convex portions  30   f ,  30   g  are intervals necessary to feed out the toner, and in the present embodiment, they are gaps of about 10 mm to about 16 mm.  
         [0076]    The toner containing unit is thus constructed, and is filled with the toner through the toner filling port  30   l  of the toner container  30  shown in FIG. 3, and is sealed by a toner cap  39 , whereby the toner containing unit  16  is provided.  
         [0077]    According to the above-described embodiment, even in a large-capacity process cartridge wherein a bridge-shaped portion for achieving the improved strength of the toner opening portion is provided in the toner container to thereby stick together and construct the sheet members of the sealing member for making it possible to absorb the relative position of the developing frame and the developer container, and the developing frame and the developer container are not welded together, it is possible to keep the strength of the toner opening portion without providing any discrete member, and prevent the exfoliation and breakage of the toner seal member.  
         [0078]    As described above, according to the present embodiment, the strength of the toner opening portion can be improved.  
         [0079]    While the invention has been described with reference to the structure disclosed herein, it is not confined to the details set forth and this application is intended to cover such modifications or changes as may come within the purposes of the improvements or the scope of the following claims.