Abstract:
A developer feeding member for use with an electrophotographic image forming apparatus to feed a developer accommodated in a developer accommodating portion, includes a shaft for receiving a driving force to rotate when the shaft is mounted in the developer accommodating portion; a flexible sheet for feeding the developer accommodated in the developer accommodating portion when the flexible sheet is mounted in the developer accommodating portion; a mounting member for mounting the flexible sheet on the shaft such that flexible sheet is movable relative to the shaft in a longitudinal direction, in a widthwise direction and in a thickness direction.

Description:
FIELD OF THE INVENTION AND RELATED ART  
       [0001]     The present invention relates to a developer conveying member, a developing apparatus, a process cartridge, and a method for attaching a developer conveying member.  
         [0002]     Here, an electrophotographic image forming apparatus means an apparatus for forming an image on a recording medium with the use of an electrophotographic image forming process. For example, an electrophotographic copying machine, an electrophotographic printer (for example, LED printer, laser beam printer, etc.), an electrophotographic facsimileing machine, an electrophotographic wordprocessor, etc., can be included in the category of an electrophotographic image forming apparatus.  
         [0003]     A process cartridge means a cartridge which is removably mountable in the main assembly of an electrophotographic image forming apparatus, and in which a minimum of a developing means as a processing means, and an electrophotographic photosensitive member, are integrally placed in order to make them removably mountable in the main assembly of the image forming apparatus.  
         [0004]     A process cartridge system has long been employed in the field of an electrophotographic image forming apparatus. A process cartridge system is a system which employs a process cartridge which is removably mountable in the main assembly of an electrophotographic image forming apparatus, and in which a minimum of a developing means as a processing means, and an electrophotographic photosensitive member, are integrally placed in order to make them removably mountable in the main assembly of the image forming apparatus. A process cartridge system makes it possible for a user to maintain an electrophotographic image forming apparatus by himself, without relying on a service person, improving substantially operational efficiency. Therefore, it is widely used in the field of an image forming apparatus.  
         [0005]     In some process cartridges, an electrophotographic photosensitive member and a developing apparatus are integrally placed, and the developing apparatus in these process cartridges is provided with a developer storage portion for storing developer. In the developer storage portion, a developer conveying member for conveying the developer in the developer storage portion is provided. Generally, a developer conveying member is made up of a rotational shaft, and a piece of flexible sheet fixed to the rotational shaft.  
         [0006]     As for a method, in accordance with the prior art, for attaching the flexible sheet to the rotational shaft, the method in which the flexible sheet is held to the rotational shaft by fixing a sheet pressing plate to the rotational shaft with small screws, adhesive, heat (thermal crimping), ultrasonic waves (ultrasonic welding), etc., while holding the flexible sheet pinched between the rotational shaft and the sheet pressing plate, has been known (Japanese Laid-open Patent Application 9-022173 and Japanese Laid-open Patent Application 2001-075343).  
         [0007]     Also has been known is the structural arrangement which relatively loosely anchors the stirring sheet (flexible sheet) to the rotational shaft in order to allow the stirring sheet to move relative to the rotational shaft in the direction parallel to the shorter edge of the stirring sheet (Japanese Laid-open Patent Application 2001-092224).  
         [0008]     However, when the above described methods, in accordance with the prior art, for attaching the flexible sheet to the shaft of the developer conveying member, for example, the method which attaches the flexible sheet to the shaft of a developer conveying member with the use of an additional member, the method which attaches the flexible sheet to the shaft by thermally or ultrasonically crimping the flexible sheet anchoring projections or the like of the shaft, or the method which thermally or ultrasonically welds the flexible sheet to the shaft by melting the flexible sheet anchoring projections or the like of the shaft, the flexible sheet was likely to become rippled. Therefore, when any of the above described methods or the like is used to attach the flexible sheet to the shaft, special attention had to be paid to prevent the flexible sheet from becoming rippled, in order to ensure that the developer is reliably conveyed.  
       SUMMARY OF THE INVENTION  
       [0009]     Thus, the primary object of the present invention is to prevent a flexible sheet attached to a rotational shaft, from rippling.  
         [0010]     Another object of the present invention is to provide a developer conveying member capable of preventing the flexible sheet of the developer conveying member from rippling even if the developer storage portion of a developing apparatus is structured so that the flexible sheet comes into, or remain in contact with, the internal surface of the developer container, a developing apparatus comprising such a developer conveying member, a process cartridge comprising such a developing apparatus, and a method for installing such a developing conveying member.  
         [0011]     Another object of the present invention is to provide a developer conveying member capable of reliably conveying the developer in the developer storage portion of a developing apparatus, a developing apparatus comprising such a developer conveying member, a process cartridge comprising such a developing apparatus, and a method for installing such a developing conveying member.  
         [0012]     These and other objects, features, and advantages of the present invention will become more apparent upon consideration of the following description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0013]      FIG. 1  is a sectional view of the process cartridge in the first embodiment of the present invention, at a plane perpendicular to the lengthwise direction of the process cartridge.  
         [0014]      FIG. 2  is a sectional view of the electrophotographic image forming apparatus in the first embodiment of the present invention, at a plane perpendicular to the lengthwise direction of the process cartridge.  
         [0015]      FIG. 3   a  is an exploded perspective view of the developer conveying member in the first embodiment, showing the method for assembling the developer conveying member.  
         [0016]      FIG. 3   b  is a perspective view of the developer conveying member in the first embodiment.  
         [0017]      FIG. 4  is a sectional view (No.  1 ) of the developer conveying member in the first embodiment, showing the structure thereof.  
         [0018]      FIG. 5  is a sectional view (No.  2 ) of the developer conveying member in the first embodiment, showing the structure thereof.  
         [0019]      FIG. 6 ( a ) is a perspective view of a part of the rotational shaft of the developer conveying member in the first embodiment, showing the structure thereof for anchoring the flexible sheet to the rotational shaft, and FIGS.  6 ( b ) and  6 ( c ) are sectional views of one of the flexible sheet anchoring claws.  
         [0020]     FIGS.  7 ( a ),  7 ( b ), and  7 ( c ) are drawings for describing the steps for assembling the developer conveying member in the first embodiment.  
         [0021]      FIG. 8  is a drawing (No.  1 ) for describing how the developer conveying member is attached to the developer storage frame, in the first embodiment.  
         [0022]      FIG. 9  is a drawing (No.  2 ) for describing how the developer conveying member is attached to the developer storage frame, in the first embodiment.  
         [0023]      FIG. 10  is a drawing (No.  3 ) for describing how the developer conveying member is attached to the developer storage frame, in the first embodiment.  
         [0024]      FIG. 11  is a drawing (No.  4 ) for describing how the developer conveying member is attached to the developer storage frame, in the first embodiment.  
         [0025]      FIG. 12  is a drawing (No.  5 ) for describing how the developer conveying member is attached to the developer storage frame, in the first embodiment.  
         [0026]      FIG. 13   a  is a sectional view of the process cartridge in the second embodiment of the present invention, at a plane perpendicular to the lengthwise direction of the cartridge, and  FIG. 13   b  is an enlargement of the portion of the  FIG. 13   a  pertinent to the description of the first embodiment.  
         [0027]      FIG. 14  is a perspective view of one of the lengthwise ends of the comparative example of the developer conveying member, showing how the flexible sheet is attached to the rotational shaft.  
         [0028]      FIG. 15  is a drawing (No.  1 ) for describing the developer storage portion in the third embodiment of the present invention.  
         [0029]      FIG. 16  is a drawing (No.  2 ) for describing the developer storage portion in the third embodiment of the present invention.  
         [0030]      FIG. 17  is a drawing (No.  3 ) for describing the developer storage portion in the third embodiment of the present invention.  
         [0031]      FIG. 18  is a drawing (No.  4 ) for describing the developer storage portion in the third embodiment of the present invention.  
         [0032]      FIG. 19  is a drawing (No.  1 ) for describing the comparative example of the developer conveying member.  
         [0033]      FIG. 20  is a drawing (No.  2 ) for describing the comparative example of the developer conveying member.  
         [0034]      FIG. 21  is a drawing for describing the comparative example of the developer container.  
         [0035]      FIG. 22  is a drawing (No.  1 ) for describing the developer conveying member in the third embodiment.  
         [0036]      FIG. 23  is a drawing (No.  2 ) for describing the developer conveying member in the third embodiment.  
         [0037]      FIG. 24  is a drawing for describing the developer container in the third embodiment. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     Embodiment 1  
       [0038]     Next, the first embodiment of the present invention will be described. First, referring to  FIGS. 1 and 2 , an electrophotographic image forming apparatus in which the process cartridge in the first embodiment is mountable will be described.  
         [0039]      FIG. 1  is a sectional view of the process cartridge  15 , which is mounted into the main assembly C of an electrophotographic image forming apparatus (which hereinafter will be referred to simply as “apparatus main assembly”) to be used for image formation. Referring to  FIG. 2 , the electrophotographic photosensitive drum (which hereinafter will be referred to simply as “photosensitive drum”)  11  is rotationally driven in the clockwise direction indicated by an arrow mark. The charge roller  12  uniformly charges to a predetermined potential level the photosensitive drum  11  while the photosensitive drum  11  is rotated. Meanwhile, a recording medium S is conveyed from the cassette  6  mounted in the bottom portion of the apparatus main assembly. In synchronism with the conveyance of the recording medium S, numerous points of the charged peripheral surface of the photosensitive drum  11  are selectively exposed by the exposing apparatus  8 . As a result, an electrostatic latent image is formed on the peripheral surface of the photosensitive drum  11 . Thereafter, the developer t in the developer container  16  is placed on the peripheral surface of the development blade  26 . Then, as development bias is applied to the development roller  18 , the developer is supplied to the peripheral surface of the photosensitive drum  11 , in the pattern of the electrostatic latent image; in other words, the electrostatic latent image is developed into a visible image, or a developer image (image formed of developer). This developer image is transferred onto the recording medium S, by the bias (voltage) applied to the transfer roller  9 . Then, the recording medium S, onto which the developer image has just been transferred, is sent into the fixing apparatus  1 , in which the developer image is fixed to the recording medium. Thereafter, the recording medium S is discharged by the pair of discharge rollers  2  into the delivery tray  3  on top of the apparatus main assembly. After the separation of the recording medium, the transfer residual developer (residual developer), that is, the developer remaining on the peripheral surface of the photosensitive drum  11  after the transfer of the developer image, is removed by the cleaning blade  14 , and the photosensitive drum  11  is used for the next image formation. After being removed from the photosensitive drum  11 , the transfer residual toner is stored in the cleaning means frame (which hereinafter will be referred to simply as “developer container”)  13 , which is a container for storing the removed developer.  
         [0040]     Referring to  FIG. 1 , the cartridge  15  in this embodiment comprises the photosensitive drum  11 , charge roller  12 , development roller  18  as a charging means, development blade  26 , and developer container  16  in which developer is stored. The charge roller  12 , development roller  18 , development blade  26 , and developer container  16  are placed in the adjacencies of the peripheral surface of the photosensitive drum  11 . Further, the cartridge  15  comprises a cleaning blade  14  as a cleaning means. The cartridge  15  also comprises a housing in which the abovementioned components are integrally placed, and is removably mountable in the apparatus main assembly C. The developing apparatus comprises: a developing means frame  17  for holding the development roller  18 ; and the developer container  16  as the developer storing portion in which developer is stored.  
         [0041]     At this time, the structure for conveying the developer in the developer container  16  will be described. Hereinafter, the lengthwise direction means the direction parallel to the axis of the photosensitive drum  11 . The developer t in the developer container  16  is conveyed toward the development roller  18  by the developer conveying member (which hereinafter will be referred to simply as “conveying member”)  21 , as the conveying member  21  is rotated in the direction indicated by an arrow mark A ( FIG. 1 ). The conveying member  21  is rotatably supported by the developer container  16 . Referring to  FIGS. 3   a  and  3   b , the conveying member  21  comprises a rotational shaft (which hereinafter may be referred to as “conveying shaft”)  22 , and a flexible sheet  25  fixed to the conveying shaft  22 .  
         [0042]     Next, referring to  FIGS. 3   a  and  3   b , the conveying shaft  22  has a main portion  22   f , a driving force transmitting portion  22   e , and a sliding portion  22   g , which are integral parts of a single-piece conveying shaft  22 . To the main portion  22   f , the flexible sheet  25  is attached by one of its lengthwise edges (ends in terms of widthwise direction of the flexible sheet  25 ), with the lengthwise edge set parallel to the main portion  22   f . The driving force transmitting portion  22   e  is attached to one of the lengthwise ends of the main portion  22   f , and receives driving force (torque) from the apparatus main assembly C, when the cartridge  15  is in the apparatus main assembly C. The driving force transmitting portion  22   e  has a driving force transmitting means such as gears, coupler, etc. The sliding portion  22   g  is attached to the other end of the main portion  22   f , and is rotatably supported by one of the walls of the developer container  16 . Incidentally, the conveying shaft  22  is attached to the developer container  16  before the flexible sheet  25  is attached to the conveying shaft  22 .  
         [0043]      FIG. 4  is a sectional view of one of the flexible sheet anchoring claws  23  of the conveying shaft  22 , and  FIG. 5  is a sectional view of one of the flexible sheet retaining portions  24  for keeping the flexible sheet  25  anchored to the conveying shaft  22 .  FIG. 6 ( a ) is a perspective view of one of the plurality of flexible sheet anchoring portions of the conveying shaft  22 . As shown in  FIGS. 3   a  and  3   b , the conveying shaft  22  has a plurality of flexible sheet anchoring portions for anchoring the flexible sheet  25  to the conveying shaft  22 . The conveying shaft  22  has a long slit  22   a  which extends in the lengthwise direction of the conveying shaft  22 . Referring to  FIG. 4 , one of the lengthwise edges portion of the flexible sheet  25  is fitted in the slit  22   a . The flexible sheet anchoring claw  23  fits into the anchoring hole  25   a  of the flexible sheet  25 . The flexible sheet anchoring claw  23  is a projection attached to (integral with) the conveying shaft  22 , and functions as a member for anchoring the flexible sheet  25  to the conveying shaft  22 . In this embodiment, the flexible sheet anchoring claw  23  is in the form of a hook.  
         [0044]     Next, how to anchor the flexible sheet  25  to the conveying shaft  22  will be described. Referring to  FIGS. 4 and 5 , the conveying shaft  22  is provided with a predetermined number of ribs  24  as a means for preventing the flexible sheet  25  from become disengaged from the flexible sheet anchoring claw  23  (preventing the flexible sheet anchoring claw  23  from coming out of the anchoring hole  25   a  of the flexible sheet  25 ). The ribs  24  are located within the aforementioned slit  22   a , in which the aforementioned flexible sheet anchoring claws  23  are also located. Referring to  FIG. 4 , the height of the flexible sheet anchoring claw  23  is roughly ⅔ of the width D of the slit  22   a . In this embodiment, the width D of the slit  22   a  is roughly 3 mm, whereas the height F of the flexible sheet anchoring claw  23  is roughly 2 mm. Referring to  FIG. 7 , designated by a referential number  22   c  is one of the opposing surfaces of the slit  22   a , which obviously extends in the lengthwise direction of the slits  22   a  (the same direction as lengthwise direction of flexible sheet  25  after its attachment to conveying shaft  22 ). The aforementioned claws  23  project from this surface  22   c . Designated by a referential number  22   d  is the other of the opposing two surfaces of the slit  22   a . The surface  22   d  is provided with a predetermined number of ribs  24 , which are aligned in the lengthwise direction of the conveying shaft  22 , with the provision of intervals large enough to accommodate one of the claws  23 , so that as seen from the lengthwise direction, the ribs  24  and claws  23  are alternately positioned, in other words, the claws  23  are positioned between the adjacent two ribs  24 . Each rib  24  is provided with a slanted portion  23   a  ( FIGS. 4 and 5 ), making it easier to insert the flexible sheet  25  into the slit  22   a  in the direction indicated by an arrow mark B ( FIG. 3   a ), because the slanted portion  23   a  can be used to guide the anchoring hole  25   a  of the flexible sheet  25  to the flexible sheet anchoring claw  23 . Referring to  FIG. 5 , the height E of the rib  24  is roughly ⅔ of the width D of the slit  22   a , and is roughly 2 mm.  
         [0045]     Next, it will be described how to attach the flexible sheet  25  to the conveying shaft  22 . FIGS.  7 ( a )-( c ) are views of one of the portions of the conveying shaft  22 , which has one of the claws  23 , and the flexible sheet  25  fitted in the slit  22   a  of the conveying shaft  22 , as seen from the direction indicated by the arrow mark B in  FIGS. 4 and 5 . The flexible sheet  25  is to be inserted into the slit  22   a  of the conveying shaft  22 , from one of the lengthwise edges (end in terms of widthwise direction of flexible sheet  25 , that is, the side having the anchoring holes  25   a ), in the arrow B direction in  FIGS. 3   a ,  4  and  5 . As the flexible sheet  25  is nudged, it begins to enter the slit  22   a  while deforming in the pattern of the gap between the claws  23  and ribs  24  because of its flexibility, as shown in  FIG. 7 ( a ). Then, the claws  23  begin to enter the anchoring holes  25   a  of the flexible sheet  25  as shown in  FIG. 7 ( b ). Then, the claws  23  completely enter the anchoring holes  25   a , one for one, and the flexible sheet  25  becomes flat again because of its resiliency, as shown in  FIG. 7 ( c ). FIGS.  6 ( b ) and  6 ( c ) show the positional relationship between the flexible sheet anchoring claw  23  and anchoring hole  25   a  after the flexible sheet anchoring claw  23  has fully entered the hole  25   a  (flexible sheet  25  has been satisfactorily anchored by claws  23 ).  FIG. 6 ( b ) is a view of the flexible sheet anchoring claw  23  as seen from the direction indicated by an arrow mark J in  FIG. 6 ( a ), and  FIG. 6 ( c ) is a view of the flexible sheet anchoring claw  23  as seen from the direction indicated by an arrow mark H in  FIG. 6 ( a ), that is, as seen from the base side of the flexible sheet anchoring claw  23 . The portion  23   b  of the flexible sheet anchoring claw  23 , which holds the flexible sheet  25  is roughly semicylindrical. The flexible sheet holding portion of the flexible sheet anchoring claw  23  is allowed to come into contact with the edge of the anchoring hole  25   a  of the flexible sheet  25 . The radius L of this semicylindrical portion of the flexible sheet anchoring claw  23  is smaller than that of the anchoring hole  25   a . In other words, the cross section of the flexible sheet holding portion  23   b  of the flexible sheet anchoring claw  23  is smaller than that of the anchoring hole  25   a , making it easier to guide the flexible sheet anchoring claw  23  into the anchoring hole  25   a . In addition, it is possible to allow the flexible sheet anchoring claw  23  to be loosely fitted in the anchoring hole  25   a , making it possible to spread the force which applies to edge of the anchoring hole  25   a  as the flexible sheet  25  is rotated by the rotation of the conveying shaft  22 , and therefore, preventing the edge of the anchoring hole  25   a  of the flexible sheet  25  from being torn by the above described force. Referring to FIGS.  6 ( a ) and  6 ( b ), the flexible sheet anchoring claw  23  is loosely fitted in the anchoring hole  25   a . Therefore, the flexible sheet  25  is allowed to move relative to the conveying shaft  22  in the lengthwise direction, as well as thickness direction (rotational direction of flexible sheet), of the flexible sheet  22 , by the distance equal to the gap between the flexible sheet anchoring claw  23  and the edge of the anchoring hole  25   a , and the distance equal to the length of the flexible sheet holding portion of the flexible sheet anchoring claw  23 , respectively. In this embodiment, the flexible sheet  25  is allowed to move relative to the conveying shaft  22 , also in the widthwise direction (radius direction of the sweeping range of the sheet), which is roughly perpendicular to both the lengthwise as well as thickness direction of the flexible sheet  25 .  
         [0046]     In this embodiment, the diameter K of the anchoring hole  25   a  is roughly 4.6 mm, and the radius L of the semicylindrical portion of the flexible sheet holding portion  23   b  of the flexible sheet anchoring claw  23  is roughly 1.5 mm. The flexible sheet anchoring claw  23  has the end portion  23   c  which perpendicularly projects from the flexible sheet holding portion  23   b  of the flexible sheet anchoring claw  23 . This portion  23   c  is the portion which makes it difficult for the flexible sheet  25  from disengaging from the conveying shaft  22 . The flexible sheet anchoring claw  23  is in the form of a hook made up of the flexile sheet holding portion  23   b , and the portion  23   c  perpendicular to the portion  23   b . Further, referring to FIGS.  7 ( a )- 7 ( c ), in order to prevent the flexible sheet  25  from disengaging from the conveying shafts  22 , the internal surface  22   d  of the slit  22 , which opposes the internal surface  22   c  of the slit  22 , is provided with the aforementioned ribs  24  aligned in the lengthwise direction of the conveying shaft  22 , with the intervals in which the plurality of claws  23  fit one for one. Thus, the flexible sheet  25  comes into contact with the ribs  24  before it allows any of the flexible sheet anchoring claws  23  to come out of the anchoring holes  25   a , being prevented from disengaging from the claws  23  (conveying shaft  22 ). To sum up, the movements of the flexible sheet  25  in the lengthwise and widthwise directions of the flexible sheet  25  are regulated by the contact between the flexible sheet anchoring claws  23  and the edges of the corresponding anchoring holes  25   a  of the flexible sheet  25 , and the movement of the flexible sheet  25  in its thickness direction is regulated by the contact between the flexible sheet  25  and ribs  24 , and the contact between the flexible sheet  25  and the internal surface  2   c  of the slit  22 . Even after the satisfactory anchoring of the flexible sheet  25  to the conveying shaft  22 , the flexible sheet  25  is allowed to remain slightly loose relative to the conveying shaft  22  as described before. Therefore, it is unlikely for a substantial amount of force to apply from the conveying shaft  22  to the flexible sheet  25 . Besides, even if a substantial amount of force applies from the conveying shaft  22  to the flexible sheet  25 , the deformation of the flexible sheet  25  can be absorbed by the edge portion of the flexible sheet  25 , on the conveying shaft cs side. Therefore, the opposite edge portion of the flexible sheet  25  from the conveying shaft  22  is unlikely to deform in the form of a ripple. Therefore, the developer conveying member  21  can reliably convey the developer.  
         [0047]     Shown in  FIG. 15  is one of the comparative examples of the structural arrangement used to attach the flexible sheet  25  to the conveying shaft  22 . In the case of this structural arrangement, if such means as small screws, heat (thermal crimping), ultrasonic waves (ultrasonic crimping), etc., are used to attached to the flexible sheet  25  to the conveying shaft  22 , stress is generated in the portion of the flexible sheet  25  in the adjacencies of the joint  34  between the flexible sheet  25  and conveying shaft  22 . In addition, no gap is provided between the flexible sheet  25  and conveying shaft  22  at the joint  34 . Therefore, the flexible sheet  25  is deformed by the stress generated in the portion of the flexible sheet  25  in the adjacencies of the joint  34 . It is possible that this stress in the flexible sheet  25  will travel to the opposite edge  25   b  of the flexible sheet  25  from the joint  34 , and cause the edge  25   b  to ripple.  
         [0048]     In comparison, in the case of such a structural arrangement as the above described structural arrangement in this embodiment for anchoring the flexible sheet  25  to the conveying shaft  22 , the portion of the flexible sheet  25  in the adjacencies of the joint  34  is allowed to relatively freely deform. Therefore, it is difficult for the force from the conveying shaft  22  to concentrate on a specific portion of the flexible sheet  25  in the adjacencies of the joint  34 , making it unlikely for stress to be generated in the portion of the flexible sheet  25  in the adjacencies of the joint  34 . The force which otherwise might generate stress throughout the flexible sheet  25  is released by the portion of the flexible sheet  25  in the adjacencies of the joint  34 , making it unlikely for the edge  25   b  of the flexible sheet  25  opposite from the joint  34  to ripple.  
         [0049]     Next, referring to  FIGS. 3   a , and  8 - 12 , the method for installing the developer conveying member  21  to the developer container  16  will be described. The conveying member  21  is attached to the developer container  16  following sequentially the steps shown in  FIGS. 8, 10 ,  11 , and  12 .  FIG. 9  is a sectional view of the developer container  16  in the state shown in  FIG. 8 , at a plane coincident with the rotational axis of the conveying member  21  and perpendicular to the bottom wall of the developer container  16 .  
         [0050]     First, a sealing member  33  ( FIG. 9 ) in the form of a ring is to be fitted around the through hole  16   c  of the developer container shell  16   a . The sealing member  33  is for preventing the developer from leaking from the developer container  16 .  
         [0051]     Next, referring to  FIGS. 8 and 9 , the conveying shaft  22  is put through the through hole  16   c , from the lengthwise end  22   g , so that the lengthwise end  22   g  will be fitted into the hole  16   d , which is not a through hole, and is located on the directly opposite side of the developer container shell  16   a  from the through hole  16   c . As the conveying shaft  22  is placed as described above, the lengthwise end  22   g  of the conveying shaft  22  is rotatably supported by the developer container shell  16   a  (wall of through hole  16   c ).  
         [0052]     Next, referring to  FIGS. 10 and 3   a , the conveying shaft  22  is positioned so that the slit  22   a  faces upward (toward lid  16   b  of developer container  16 ). Then, the flexible sheet  25  is to be inserted into the slit  22   a , with the slit  22   a  facing upward as described above, so that the aforementioned flexible sheet anchoring claws  23  of the conveying shaft  22  fit into the anchoring holes  25   a  of the flexible sheet  25 . Then, the lid  16   b  of the developer container  16  is to be welded to the developer container shell  16   a  with the use of ultrasonic waves, heat, or the like.  
         [0053]     As described above, the conveying member  21  in this embodiment has the rotatable conveying shaft  22 , and flexible sheet  25 , which is attached to the conveying shaft  22  by one of the lengthwise edges (end in terms of widthwise direction of sheet). Thus, as the flexible sheet  25  is rotated by the rotation of the conveying shaft  22 , the developer is conveyed. The flexible sheet  25  is provided with the plurality of anchoring holes  25   a , which are located along one of the lengthwise edges thereof, and the conveying shaft  22  is provided with the slit  22   a , into which the portion of the flexible sheet  25  having the anchoring holes  25   a  is inserted. Within the slit  22   a , the plurality of anchoring claws  23  which fit into the plurality of anchoring holes  25   a  of the flexible sheet  25 , one for one, and the plurality of ribs  24 , are alternately positioned in the lengthwise direction of the conveying shaft  22 . More specifically, the plurality of flexible sheet anchoring claws  23  project from the internal surface  22   c  of the slit  22   a , whereas the plurality of ribs  24  project from the internal surface  22   d  of the slit  22   a , which directly opposes the internal surface  22   c . Further, in terms of the lengthwise direction, the ribs  24  and claws  23  are alternately positioned. With the provision of the above described structural arrangement, the flexible sheet  25  does not ripple while or after it is anchored to the conveying shaft  22 .  
         [0054]     Moreover, with the provision of the above described structural arrangement, the flexible sheet  25  can be anchored to the conveying shaft  22  simply by inserting the flexible sheet  25  into the slit  22   a  of the conveying shaft  22 , eliminating the need for the tools necessary if the flexible sheet  25  is to be attached to the conveying shaft  22  by direct thermal welding, ultrasonic welding, or the like method. Further, since no tool is required to attach the flexible sheet  25  to the conveying shaft  22 , it is possible to attach the flexible sheet  25  to the conveying shaft  22 , while the shaft  22  is within the developer container shell  16   a ; in other words, it is possible to attach the flexible sheet  25  to the conveying shaft  22  after the conveying shaft  22  is fully inserted into the developer container shell  16   a.    
         [0055]     Further, in the case of the conveying member  21 , the flexible sheet  25  of which had to be attached to the conveying shaft  22  after the flexible sheet  25  was attached to the conveying shaft  22 , the driving force transmitting member had to be attached to the conveying shaft  22  from outward of the developer container shell after the placement of the conveying shaft  22  into the developer container shell. Therefore, the driving force transmitting member must be a component independent from the conveying shaft  22 , adding to the number of assembly steps. In comparison, in the case of the conveying member  21  in this embodiment, the flexible sheet  25  can be attached to the conveying shaft  22  after the conveying shaft  22  is completely inserted to the developer container shell  16   a . Therefore, the main portion  22   f  and driving force transmitting portion  22   e  of the conveying shaft  22  can be formed as integral parts of the single-piece conveying shaft  22 .  
         [0056]     Forming the conveying shaft  22  having the main portion  22   f  and driving force transmitting portion  22   e  in a single piece reduces component cost, and also, assembly cost, and therefore, substantially reduces the cost of the developer conveying member, and substantially improves the developer conveying member in assembly efficiency as well as quality.  
       Embodiment 2  
       [0057]     Next, the second embodiment of the present invention will be described. This embodiment is such a case that, in order to convey the waste developer in the waste toner container  13  for storing the residual developer after the residual developer is removed from the peripheral surface of the electrophotographic photosensitive drum  11 , the conveying member  21  placed in the developing apparatus in the first embodiment is placed in the waste toner container  13 .  
         [0058]     Referring to  FIG. 13 , the structure of the process cartridge  15  in this embodiment will be described.  FIG. 13 ( a ) is a sectional view of the cartridge  15 , at a plane perpendicular to the lengthwise direction of the cartridge  15 , and  FIG. 13 ( b ) is an enlarged sectional view of the portion of  FIG. 13 ( a ) pertinent to this embodiment. The cartridge  15  in this embodiment comprises the photosensitive drum  11 , charge roller  12 , development roller  18 , development blade  26 , developer container  16  in which developer t is stored, and cleaning blade  14  as a cleaning means. The charge roller  12 , development roller  18 , development blade  26 , developer container  16 , and cleaning blade  14 , are placed in the adjacencies of the peripheral surface of the photosensitive drum  11 . The cartridge  15  also comprises a housing in which the abovementioned components are integrally placed, and which is removably mountable in the apparatus main assembly C. The structure of the main assembly of the image forming apparatus in this embodiment is the same as the main assembly C of the image forming apparatus in the first embodiment shown in  FIG. 2 , and therefore, will not be described here.  
         [0059]     At this time, the internal structure of the waste developer container  13  as the waste toner storage portion, for conveying the waste toner ta will be described. The transfer residual developer, or the developer remaining on the peripheral surface of the photosensitive drum  11  after the transfer of the developer image onto the recording medium S, is removed by the cleaning blade  14 , and the removed transfer residual developer is stored in the waste developer container  13 . In the waste developer container  13 , the developer conveying member  21  is rotated in the direction indicated by an arrow mark A in  FIG. 13 ( b ), and therefore, the removed waste developer ta is conveyed inward (side opposite to photosensitive drum  11 ) of the waste developer container  13  by the developer conveying member  21 . The waste developer conveying member  21  has the conveying shaft  22  rotatably supported by the remove waste developer container  13 , and a flexible sheet  25  anchored to the conveying shaft  22 .  
         [0060]     Next, the method for installing the conveying member  21  into the frame of the removed waste developer container  13  will be described. This is the same as the method for installing the developer conveying member  21  into the developer container  16 , in the first embodiment. That is, first, the conveying shaft  22  is inserted into the removed waste developer container  13 . It should be noted here that the conveying shaft  22  is inserted into the removed waste developer container  13  before the cleaning blade  14  is attached to the removed waste developer container  13 . Then, the flexible sheet  25  is inserted into the slit ( 22   a ) of the conveying shaft  22 , anchoring thereby the flexible sheet  25  to the conveying shaft  22 . The method, in this embodiment, for anchoring the flexible sheet  25  to the conveying shaft  22  is the same as that in the first embodiment, and therefore, will not be described here to avoid the repetition of the same description. Thereafter, the development unit frame  17  is attached to the removed waste developer container (cleaner unit frame)  13 . In this embodiment, the flexible sheet  25  can be attached to the conveying shaft  22  after the conveying shaft  22  is fully inserted into the removed waste developer container  13 . Therefore, it is possible to form, in a single piece, the conveying shaft  22  of the conveying member  21  having the main portion and driving force transmitting portion ( 22   e ), as it is in the first embodiment. Therefore, not only can the conveying member  21  be reduced in component count, but also, it can be improved in assembly efficiency. Therefore, it is possible to reduce the conveying member  21  in cost.  
         [0061]     Incidentally, the first and second embodiments of the present invention may be combined. In other words, the developer conveying member in the developer container  16 , and the removed waste developer conveying member in the removed waste developer container  13 , may be employed in combination to achieve both the effects obtainable by the first embodiment, and the effects obtainable by the second embodiment.  
       Embodiment 3  
       [0062]     Next, the third embodiment of the present invention will be described. The main assembly of the image forming apparatus, process cartridge, and developing apparatus, in this embodiment are the same in structure as those in the first embodiment. Therefore, their structures will not be described to avoid the repetition of the same description.  
         [0063]     At this time, referring to  FIG. 15 , the developer t stored in the developer container  16 , and the structure of the removed waste developer conveying shaft  22  of the removed waste developer conveying member  21 , and the structure of the flexible sheet  25 , in this embodiment, will be described.  
         [0064]      FIG. 15  is a sectional view of the developer container  16 . The removed waste developer conveying member  21  comprising the conveying shaft  22  and flexible sheet  25  is rotated in the direction indicated by an arrow mark A in the drawing, by the driving force received through the driving force transmitting member (unshown).  
         [0065]     The flexible sheet  25  is rotated in the developer container  16  while remaining in contact with the bottom wall as well as the top wall of the developer container  16 . Therefore, the flexible sheet  25  deforms in a manner to conform to the shape of the developer container  16  as shown in the drawing. As the conveying member  21  is rotated, the developer t is conveyed to the development roller (unshown) through the developer delivery opening  32 . Designated by a referential letter M is the top surface of the body of the developer (interface between body of developer and body of air in the internal space of the developer container  16  not occupied by body of developer).  
         [0066]     Referring to  FIG. 15 , in the developer container  16 , a pair of lenses  30  and  31  as a means for detecting the amount of the developer remaining in the developer container  16  are located. The beam of light L in  outputted from the apparatus main assembly (unshown) reaches the surface  30   a  of the lens  30 , located within the developer container  16 , after being transmitted through the lens  30  while being reflected and deflected. Referring to  FIG. 16 , there is the developer t having accumulated on the lens  30 , in the developer container  16 ; in other words, the surface  30   a  of the lens  30  is covered with the developer t. The internal state of the developer container  16  shown in  FIG. 15  is the state which was realized as the conveying member  21  in the developer container  16  which was in the state shown in  FIG. 16 , was rotated (in direction indicated by arrow mark A in drawing) by the rotational force transmitted thereto from the driving force transmitting member. The conveying member  21  conveys the developer t to the development roller through the developer delivery opening  32 . At the same time, one of the lengthwise edges of the flexible sheet  25  sweeps away the developer t on the surface  30   a  of the lens  30 . As the internal state of the developer container  16  becomes as shown in  FIG. 15 , the beam of light L in  having reached the surface  30   a  of the lens  30  travels through the internal space of the developer container  16 , and reaches the surface  31   a  of the lens  31  fitted in the top wall of the developer container  16 . It should be noted here that the surface  31   a  of the lens  30  has also been swept by the flexible sheet  25  as the conveying member  21  was rotated; the developer having adhered to the surface  31   a  of the lens  31  has been removed by the flexible sheet  25 . In other words, in this state, the lens  31  is clean enough for the beam of light L in  to transmit through it. After reaching the surface  31   a  of the lens  31 , the beam of light L in  travels through the lens  31 , while being reflected and refracted, and returns as the beam of light L out  into the apparatus main assembly.  
         [0067]     Generally, in the case of a method for detecting the remaining amount of the developer with the use of light transmission, the remaining amount of the developer is determined by detecting the length of time the beam of light L in  outputted from the apparatus main assembly returns as the beam of light L out  to the apparatus main assembly through the inside of the developer container during a single rotation of the conveying member  21 . Thus, in the case of such a method for detecting the remaining amount of the developer in the developer container  16  as the above described one, the flexible sheet  25  of the conveying member  21  is required to reliably wipe clean the surface  30   a  of the lens  30  so that the beam of light L in  having reached the surface  30   a  of the lens  30  is allowed to travel through the inside of the developer container  16 .  
         [0068]     Although, in this embodiment, a method which uses the changes in the length in time of the light transmission through the developer container  16  is used as the method for detecting the remaining amount of the developer in the developer container  16 , the present invention is also compatible with a method which uses an electrode in the form of a piece of plate to detect the changes in the amount of static electricity, or a method which uses a piezoelectric element. In the case of these methods, the flexible sheet  25  wipes clean the detective surface of the electrode for detecting the changes in the electrostatic capacity, or the detective surface of the piezoelectric element.  
         [0069]      FIG. 17  is a sectional perspective view of the developer container  16 , which is in the state shown in  FIG. 16 , showing the state thereof.  FIG. 17  does not show the developer, but, the surface  30   a  of the lens  30  is covered as it is in  FIG. 16 ; the developer has accumulated on the surface  30   a  of the lens  30 . As the conveying member  21  in the state shown in  FIG. 17  is rotated by the rotational driving force it receives through the driving force transmitting member, the state of the conveying member  21  changes into the state shown in  FIG. 18 .  
         [0070]      FIG. 18  is a sectional perspective view of the developer container  16  which is in the state shown in  FIG. 15 . In  FIG. 18 , the developer on the lens  30  has been conveyed away by the flexible sheet  25  of the conveying member  21 , and the surface  30   a  of the lens  30  has been wiped clean by the edge  25   b  of the flexible sheet  25 ; in other words, the developer has been removed from the surface  30   a . Thus, the developer container  16  is in the state in which the light from the apparatus main assembly can travel through the developer container  16 . If a gap d exists between the widthwise edges (ends in terms of lengthwise direction) of the flexible sheet  25  and corresponding side walls  16   f  of the developer container  16 , a certain amount of the developer slips through the gap d as the developer is conveyed by the flexible sheet  25 . Incidentally, the side walls  16   f  of the developer container  16  are roughly vertical. Thus, if the gap d exists, the developer sometimes reaches the surface  30   a  of the lens  30  while, or immediately after, the flexible sheet  25  cleans the surface  30   a  of the lens  30 . In such a case, the light having reached the lens  30  is not allowed to transmit through the inside of the developer container  16 , making it impossible to detect the remaining amount of the developer in the developer container  16 . Therefore, it is desired that there is no gap d between the widthwise edges  25   c  of the flexible sheet  25  and the corresponding side walls  16   f  of the developer container  16 . In other words, it is desired that after the installation of the conveying member  21  into the developer container  16 , the widthwise edges  25   c  of the flexible sheet  25  remain flatly in contact with the side walls  16   f  of the developer container  16  as the conveying member  21  is rotated by the driving force transmitted thereto. Further, if the lengthwise edge  25   b , that is, the opposite edge from the conveying shaft  22 , of the flexible sheet  25  has a ripple, or ripples, while the lengthwise edge  25   b  cleans the surface  30   a  of the lens  30 , a certain amount of the developer slips through the gaps created by the ripple; in other words, the flexible sheet  25  fails to satisfactorily clean the surface  30   a  of the lens  30 . Therefore, it is desired that the lengthwise edge  25   b  of the flexible sheet  25  does not have a ripple, and does not ripple; the lengthwise edge  25   b  of the flexible sheet  25  is desired to be as straight as possible.  
         [0071]     Next, in consideration of the above description of this embodiment, the conveying member  21  having such a flexible sheet ( 25 ), at least one of the widthwise edges  25   c  of which remains in contact with the side wall  16   f  of the developer container  16  as the conveying member  21  is rotated, will be described in comparison with the comparative example of the conveying member ( 21 ).  
         [0072]      FIG. 19  shows one of the comparative examples of a developer conveying member ( 21 ), the developer conveying shaft  22  and flexible sheet  25  of which are firmly fixed to each other by thermal crimping, ultrasonic crimping, or the like. Designated by a referential number  34  is the joint between the two. As shown in  FIG. 15 , in the case of the method, in this comparative example, for attaching the flexible sheet  25  to the conveying shaft  22 , the lengthwise edge  25   b  of the flexible sheet  25  sometimes becomes rippled as soon as the flexible sheet  25  is attached to the conveying shaft  22 . The conveying member  21  shown in  FIG. 19  is an example of the conveying member  21 , the flexible sheet of which was carefully attached to the conveying shaft  22  in order to prevent the lengthwise edge  25   b  of the flexible sheet  25  from becoming rippled when attaching the flexible sheet  25  to the conveying shaft  22 . In the case of this conveying member  21 , the widthwise edge  25   c  of the flexible sheet  25  remains in contact with the side wall  16   f  of the developer container  16  while the conveying member  21  is rotated. In other words, the portion of the flexible sheet  25  in the adjacencies of the widthwise edge  25   c  of the flexible sheet  25  is enable to hypothetically enter the side wall  16   f  of the developer container  16  by a distance of d.  FIG. 20  shows the comparative example of the developer conveying member  21  shown in  FIG. 19 , the portion of the flexible sheet  25  in the adjacencies of the widthwise edge  25   c  of the flexible sheet  25  is deformed by the width of d. The flexible sheet  25  is firmly fixed to the conveying shaft  22 , with the presence of no gap between the portions of the flexible sheet  25  and conveying shaft  22  in the joint  34 . Therefore, the flexible sheet  25  has not deformed in the joint  34 . Consequently, a ripple appears at the lengthwise edge  25   b  of the flexible sheet  25 . This ripple which occurs along the lengthwise edge  25   b  of the flexible sheet  25  is undesirable from the standpoint of the developer conveyance, and the cleaning of the developer remainder detecting means, as described above.  FIG. 21  shows the above described comparative example of the conveying member  21  after its installation into the developer container  16 . The flexible sheet  25  is bent in a manner to conform to the bottom wall of the developer container  16 . In other words, the flexible sheet  25  is pressed upon the bottom wall of the developer container  16 . Therefore, the ripple of the lengthwise edge  25   b  of the flexible sheet  25  is reduced to an amount much smaller than that shown in  FIG. 20 , but it is still there. In other words, the stress generated in the flexible sheet  25  is released only at the lengthwise edge  25   b . Therefore, a certain amount of the ripple still remains at the lengthwise edge  25   b.    
         [0073]     In comparison,  FIG. 22  shows the conveying member  21  in this embodiment. Also in this embodiment, the flexible sheet  25  is anchored to the conveying shaft  22  as the flexible sheet anchoring claws  23  are put through the flexible sheet anchoring holes  25   a  of the flexible sheet  25 , as it is in the above described first embodiment.  FIG. 23  shows the state of the conveying member  21  after the widthwise edge  25   c  of the conveying member  21 , which was in the state shown in  FIG. 22 , was bent by the width of d. In this embodiment, the flexible sheet  25  is not firmly attached to the conveying shaft  22 ; the flexible sheet anchoring claws  23  are simply put through the anchoring holes  25   a  of the flexible sheet  25 , which are greater in size than the cross sections of the claws  23 . Therefore, the flexible sheet  25  is allowed to move relative to the conveying shaft  22  in the lengthwise direction (parallel to axis X in drawing) of the flexible sheet  25 , and also, the thickness (rotational) direction (parallel to axis Z in drawing) of the flexible sheet  25 . Therefore, if the widthwise edge  25   c  of the flexible sheet  25  is bent by the width of d, the stress generated in the flexible sheet  25  by the bending of the flexible sheet  25  can be released at the joint between the conveying shaft  22  and flexible sheet  25 , unlike what occurs in the case of the comparative example. Therefore, the amount of the ripple which might occur along the lengthwise edge  25   b  of the flexible sheet  25  is smaller than that in the case of the comparative example. Moreover, in this embodiment, the flexible sheet  25  is allowed to move relative to the conveying shaft  22  also in the widthwise direction (parallel to axis Y in drawing), making it much easier for the aforementioned stress to be released compared to the comparative example.  
         [0074]     Shown in  FIG. 24  is the state of the developer conveying member  21  after the installation of the developer conveying member  21  into the developer container  16 . In this state, the stress generated in the flexible sheet  25  can be released at the joint between the lengthwise edge  25   b , or the free edge, of the flexible sheet  25 , and the conveying shaft  22 . Therefore, the portion of the flexible sheet  25  in the adjacencies of the lengthwise edge  25   b  of the flexible sheet  25  remains straight, conforming perfectly to the flat bottom wall of the developer container  16 , even through the amount of the flexible sheet distortion which occurs at the joint between the flexible sheet  25  and conveying shaft  22  is greater in this case than that in the case of the comparative example. Therefore, not only is the developer in the developer container  16  is satisfactorily conveyed, but also, the surface of the means for detecting the remaining amount of the developer in the developer container  16  is satisfactorily cleaned.  
         [0075]     In summary, according to this embodiment, even if the developer conveying member for conveying the developer in the developer container doubles as the means for cleaning the developer amount detecting means with which the developer container is to be provided, the amount by which the developer slips through the gaps between the developer conveying member and developer container walls can be made substantially smaller compared to the prior art. In other words, this embodiment of the present invention improve the developer conveying member in the function of conveying the developer, but also, in the function of cleaning the developer remainder amount detecting means.  
         [0076]     Incidentally, in the above described first to third embodiments, “conveying the developer in the developer container” also means “stirring the developer in the developer container”.  
         [0077]     According to the present invention, it is possible to prevent the flexible sheet attached to the shaft from rippling.  
         [0078]     Also according to the present invention, it is possible to prevent the flexible sheet attached to the shaft from rippling, even if the developer container is structured so that the flexible sheet comes into, or remains in contact with, the internal surfaces of the developer container.  
         [0079]     Further, according to the present invention, it is possible to provide a developer conveying member capable of reliably conveying the developer in a developer container, a developing apparatus comprising such a developer conveying member, and a process cartridge comprising such a developing apparatus.  
         [0080]     While the invention has been described with reference to the structures 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.  
         [0081]     This application claims priority from Japanese Patent Application No. 261461/2004 filed Sep. 8, 2004, which is hereby incorporated by reference.