Patent Publication Number: US-8116666-B2

Title: Developer container and image forming apparatus that incorporates the developer container

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a developer container and an image forming apparatus that incorporates the developer container. 
     2. Description of the Related Art 
     Conventional electrophotographic image forming apparatus such as printers, facsimile machines, and copying machines use electrophotographic technology. A charging roller charges the circumferential surface of a photoconductive drum uniformly. An exposing unit illuminates the charged surface of the photoconductive drum in accordance with print data to form an electrostatic latent image. A developing roller supplies a developer material to the electrostatic latent image, thereby developing the electrostatic latent image into a developer image. The developer image is then transferred onto a print medium such as paper. A fixing unit fixes the developer image on the print medium into a permanent image. A developer container such as a toner cartridge holds a developer material therein and is detachably attached to the image forming apparatus. 
     A developer container generally includes a housing and a shutter that slidablly fits into the housing. The housing has a developer discharging opening formed therein and the shutter has another developer discharging opening formed therein. When the shutter slides to a position where the opening of the shutter is in alignment with the opening of the housing, the developer is discharged from the developer container into a developing unit of the image forming apparatus. 
     However, a conventional developer container suffers from a drawback in that a developer material adhering to an inner wall surface of the container may not be used efficiently. 
     SUMMARY OF THE INVENTION 
     The present invention was made in view of the aforementioned drawbacks. 
     An object of the invention is to provide an image forming apparatus in which the amount of a developer material adhering to the inner wall of a developer material container is minimized. 
     An object of the invention is to provide a developer container having an inner wall surface in which peaks and valleys are formed such that when an inner housing slides in an outer housing, vibration is generated to cause the developer material adhering to the inner wall to fall. 
     A developer material container holds a developer material therein, the developer material container being attached to an image forming apparatus. The container includes a housing and a shutter. The housing holds the developer material therein, the housing including a first engagement portion and an opening through which the developer material is discharged into the image forming apparatus. The first engagement portion includes a first surface. The shutter is fitted into the housing and is slidable relative to the housing. The shutter includes a second engagement portion that engages the first engagement portion when the shutter slides relative to the housing, and a shutter wall that either opens or closes the opening when the shutter slides relative to the housing. The second engagement portion includes a second surface and either at least one second projection formed on the second surface or at least one first recess formed in the second surface. 
     The at least one first projection projects from the first surface toward the shutter, and the at least one second projection projects from the second surface toward the housing. 
     The first engagement portion includes at least one second recess formed in the first surface. The at least one second projection projects from the second surface toward the housing. 
     The first engagement portion includes at least one first projection that projects from the first surface toward the shutter. The at least one first recess is formed in the second surface. 
     A developer material container holds a developer material therein, the developer material container being attached to an image forming apparatus. The container includes a housing and a shutter. The housing holds the developer material therein. The housing includes a first engagement portion and an opening formed therein through which the developer material is discharged into the image forming apparatus. The shutter is fitted into the housing and includes a shutter wall that opens and closes the opening when the shutter slides relative to the housing. The shutter includes a second engagement portion that slides on the first engagement portion. The first engagement portion slides on the second engagement portion such that the developer container vibrates. 
     An image forming apparatus incorporating the developer material container described above. The image forming apparatus includes: 
     an image bearing body; 
     a charging section that charges a surface of the image bearing body; 
     an exposing section that illuminates the charged surface of the image bearing body to form an electrostatic latent image; 
     a developing section that supplies the developer material to the electrostatic latent image to form a developer image; 
     a transfer section that transfers the developer image onto a print medium; and 
     a fixing section that fixes the developer image on the print medium into a permanent image. 
     Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limiting the present invention, and wherein: 
         FIG. 1  is a cross-sectional view illustrating a general configuration of an electrographic image forming apparatus of a first embodiment; 
         FIG. 2  is a perspective illustrating the process cartridge when the toner cartridge has been attached to the process cartridge; 
         FIG. 3  is a longitudinal cross-sectional view of the process cartridge taken along a line A-A of  FIG. 2 ; 
         FIG. 4  is a perspective view of the toner cartridge shown in  FIG. 2 ; 
         FIG. 5  is a partial perspective view of the housing on a side of the housing opposite the knob; 
         FIG. 6  is a partial perspective view of the toner cartridge; 
         FIG. 7  is a perspective view of the shutter; 
         FIG. 8  is a partial perspective view of the housing shown in  FIG. 6  with a part of the housing cut away; 
         FIG. 9  is an enlarged view of a portion C of  FIG. 8 ; 
         FIG. 10  is a cross-sectional view of the toner cartridge taken along a line B-B of  FIG. 4 ; 
         FIG. 11  is an enlarged cross-sectional view of a pertinent portion when the knob shown in  FIG. 10  is rotated in a direction shown by arrow A; 
         FIG. 12  illustrates the curved guides in the shape of a short cylinder; 
         FIG. 13  is a perspective view illustrating a portion of the locking mechanism on the process cartridge side; 
         FIG. 14  is a perspective view of a portion of the locking mechanism on the toner cartridge side; 
         FIG. 15A  is a front view of the toner cartridge before the toner cartridge is attached to the process cartridge; 
         FIG. 15B  is a front view of the toner cartridge after the toner cartridge has been attached to the process cartridge; 
         FIG. 15C  is a front view of the toner cartridge when the knob has been rotated from the position shown in  FIG. 15B  to an opening position; 
         FIG. 16A  is a cross sectional view of the toner cartridge and the process cartridge shortly after the toner cartridge has been attached to the process cartridge; 
         FIG. 16B  is a cross sectional view of the toner cartridge and the process cartridge when the knob is operated toward the opening position, but shortly before the discharging opening is opened; 
         FIG. 16C  is a cross sectional view of the toner cartridge and the process cartridge when the knob is operated to the opening position; 
         FIG. 17  illustrates a modification to the shape of the recess; 
         FIG. 18  illustrates another modification to the shape of the recess; 
         FIG. 19  illustrates a modification to the shape of the rib; 
         FIG. 20  is an enlarged view of the recess; 
         FIG. 21  illustrates a yet another modification in which the housing has a recess formed in the inner wall surface of the housing; 
         FIG. 22  is a perspective view of the housing shown in  FIG. 6  with a portion of the housing cut away; 
         FIG. 23  is an enlarged view of a portion D of  FIG. 22 ; 
         FIG. 24  is a simplified longitudinal cross-sectional view of the toner cartridge; 
         FIG. 25  is an enlarged cross-sectional view when a knob shown in  FIG. 24  has been rotated in a direction shown by arrow A; and 
         FIG. 26  illustrates a modification to the shape of the rib. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     First Embodiment 
       FIG. 1  is a cross-sectional view illustrating a general configuration of an electrographic image forming apparatus  1  of a first embodiment. 
     Referring to  FIG. 1 , the electrographic image forming apparatus  1  incorporates a process cartridge  2  that employs electrophotographic technology to print images. The process cartridge  2  is detachably attached into the image forming apparatus  1 , and functions to form a developer image (e.g., toner image). A paper cassette  3  holds a stack of print medium such as print paper. The print medium is transported through transport paths  4 ,  5 , and  6 . A hopping roller  7  feeds a top page of the stack of print medium from the paper cassette  3  into the transport path  4 . Registration rollers  8  and  9  advance the print medium into the process cartridge  2  in timed relation with image formation on a photoconductive drum  25 . 
     When the print medium passes through the process cartridge  2 , the developer image is transferred on to the print medium. Then, the print medium in the transport path  5  passes through a fixing point defined between a backup roller  11  and a heat roller  12 , the developer image on the print medium is fused by heat and pressure into a permanent image. Discharging rollers  13 - 16  transport the print medium along the transport path  6  in the image forming apparatus  1 . A controller  27  performs the overall control of the image forming apparatus  1  during printing. 
       FIG. 2  is a perspective view illustrating the process cartridge  2  when the toner cartridge  18  has been attached to the process cartridge  2 .  FIG. 3  is a cross-sectional view of the process cartridge  2  taken along a line A-A of  FIG. 2 . The toner cartridge  18  holds a developer (e.g., toner)  32  therein, and is attached to the process cartridge  2 . The process cartridge  2  includes an inlet  41  that faces an outlet  34  formed in the bottom of a later described housing  28  of the toner cartridge  18 . 
     The process cartridge  2  includes a toner reservoir  20  therein that holds the toner  32  received from the toner cartridge  18 . A toner supplying roller  21  supplies the toner  32  to the surface of the developing roller  22 . The developing roller  22  in turn supplies the toner  32  to the surface of the photoconductive drum  32 . A developing blade  23  forms a thin layer of the toner  32  on the surface of the developing roller  22 . A charging roller  24  uniformly charges the entire circumferential surface of the photoconductive drum  25 . The exposing unit  17  is a printhead that takes the form of a light emitting diode (LED) head. The exposing unit  17  illuminates the charged surface of the photoconductive drum  25  in accordance with print data to form an electrostatic latent image on the charged surface of the photoconductive drum  25  ( FIG. 3 ). The electrostatic latent image is then developed with the toner  32  into the developer image. A transfer roller  10  transfers the developer image from the photoconductive drum  25  onto the print medium in the transport path  5 . A cleaning roller  26  removes the residual toner  32  from the photoconductive drum  25  after the transfer of the developer image onto the print medium. 
       FIG. 4  is a perspective view of the toner cartridge  18  shown in  FIGS. 2 and 3 .  FIG. 5  is a partial perspective view of a portion on a side of the housing  28  opposite a knob  35 .  FIG. 6  is a partial perspective view of the toner cartridge  18  near the knob  35 . 
     The housing  28  has a longitudinally extending semi-cylindrical lower half  28   a  and a longitudinally extending rectangular parallelpiped upper half  28   b . The cylindrical lower half  28   a  is contiguous with rectangular parallelpiped upper half  28   b . The rectangular parallelpiped upper half  28   b  provides spaces  19   a  ( FIG. 6 ) for greater toner holding capacity. The outlet  34  is formed in the bottom of the lower half  28   a.    
       FIG. 7  is a perspective view of the shutter  29 . 
     A shutter  29  has a generally cylindrical shape, and is received in the housing  28  such that the shutter  29  is in sliding contact with the inner wall surface of the lower half  28   a.    
     The rotary knob  35  is formed in one piece with the shutter  29  or is securely assembled to the shutter  29 , and is at a longitudinal end of the toner cartridge  18 . Operating the rotary knob  35  to an opening position causes a shutter portion  36  to open the outlet  34 , allowing the toner  32  to be supplied into the toner reservoir  20  of the process cartridge  2 . Operating the knob  35  to a closing position causes the shutter portion  36  to close the outlet  34 , stopping supply of the toner  32  into the toner reservoir  20  and locking the toner cartridge  18  to the process cartridge  2 . Curved guides  37  have one or more projections  31  ( FIG. 8 ) formed on the outer curved surfaces  37   a  but are not shown in  FIG. 7  for the sake of simplicity. 
       FIG. 8  is a partial perspective view of the housing  28  shown in  FIG. 6  with a part of the housing  28  cut away. 
     The shutter  29  includes the shutter portion  36  in the shape of a partial cylindrical wall and curved guides  37  in the shape of a partial ring or an arc. When the shutter  29  rotates in the housing  28 , the shutter portion  36  rotates in sliding contact with the inner wall of the cylindrical lower half  28   a . A sealing member (not shown) formed of a resilient material may be attached to the outer surface of the shutter portion  36 . The curved guides  37  have one or more projections  31  formed on the outer curved surfaces  37   a . The outer curved surfaces  37   a  lie in a substantially cylindrical plane in which the outer surface of the shutter portion  36  lies. The projections  31  project substantially radially toward the housing  28  and extend in a direction parallel to a rib  30  formed on an upper inner surface of the rectangular parallelpiped upper half  28   b.    
     A toner-discharging opening  38  is formed in the shutter  29  adjacent to the shutter portion  36 . When the shutter  29  rotates relative to the housing  28  to the opening position, the toner-discharging opening  38  becomes aligned with the outlet  34  formed in the bottom wall of the housing  28 . The toner-discharging opening  38  is made sufficiently larger than the outlet  34 . 
     The toner cartridge  18  includes a toner chamber  19  ( FIGS. 5 and 6 ) that holds the toner  32  therein. When the rotary knob  35  is rotated to the opening position, the shutter portion  36  opens the outlet  34  so that the developer  32  is discharged from the toner chamber  19  through the outlet  34  into a toner reservoir  20  of the process cartridge  2 . When the knob  35  has been rotated completely to the opening position, a later described locking mechanism completely locks the toner cartridge  18  to the process cartridge  2 . 
       FIG. 9  is an enlarged view of a portion C of  FIG. 8 . Referring to  FIGS. 5-9 , the housing  28  further includes the rib  30  formed on the upper inner surface of the rectangular parallelpiped upper half  28   b . The rib  30  extends in the longitudinal direction of the housing  28  and extends toward the shutter  29 . The rib  30  contacts the curved guides  37  of the shutter  29  and cooperates with the lower half  28   a  to hold the shutter  29  in place. In other words, when the shutter  29  rotates in the housing  28 , the shutter  29  is guided by the rib  30  and the lower half  28   a . One or more of the ribs  30  may be provided for greater effect. 
       FIG. 10  is a cross-sectional view of the toner cartridge  18  taken along a line B-B of  FIG. 4 .  FIG. 11  is an enlarged partial cross-sectional view of a pertinent portion D of  FIG. 10  when the knob  35  shown in  FIG. 10  is rotated in a direction shown by arrow A. 
     The rib  30  includes a flat surface  30   a  and side surfaces  30   b  and  30   c  contiguous to the flat surface  30   a . The side surfaces  30   b  and  30   c  form a tapered portion of the rib  30  ( FIG. 11 ). The projections  31  are semi-cylindrical projections having a substantially semicircular cross section. The rib  30  engages the curved guides  37  such that the rib  30  and the curved guides  37  guide the rotation of the shutter  29  when the shutter  29  rotates relative to the housing  28 . When the shutter  29  rotates, the projections  31  interfere with the rib  30  and are then pressed by the rib  30  so that the curved guides  37  resiliently deform in a direction away from the rib  30 . The deformation of the curved guides  37  causes the projections  31  to slip over the rib  30  into disengagement from the rib  30 . Shortly after the projections  31  disengage from the rib  30 , the outer curved surfaces  37   a  of the curved guides  37  slide on the rib  30 , vibrating due to abrupt disengagement of the projections  31  from the rib  30 . The side surfaces  30   b  help the projections  31  climb over the rib  30 . It is to be noted that when the rib  30  is between adjacent projections  31 , the curved guides  37  are in contact with the flat surface  30   a  of the rib  30  but are not deformed significantly. 
     The projections  31  are formed on the outer curved surface  37   a  of each of the curved guides  37 . While a plurality of projections  31  are used in the first embodiment, any number of inner projections  31  may be used. 
     The flat surface  30   a  of the projection  30  includes a dimension L 1  in a direction of rotation of the curved guides  37 , the dimension L 1  being greater than a dimension of the projection  31  in the direction of rotation of the curved guides  37 . The projections  31  are spaced apart by a distance L 3 , which is longer than the dimension L 1  of the flat surface  30   a  of the rib  30 . Thus, when the shutter  29  rotates relative to the housing  28 , the rib  30  will not extend over two adjacent projections  31  simultaneously at any moment, thereby generating a sufficient amount of vibration of the shutter  29  shortly after projection  31  disengages from the rib  30 . Providing that the aforementioned conditions are met, the cross section of the inner projections  31  may have a radius of 0.2 mm, the flat surface  30   a  may have a dimension of 3 mm in the direction of rotation of the curved guides  37 , and the rib  30  may project by 2.6 mm from the inner wall surface of the housing  28 . Further, the projections  31  may have a radius of 0.12 mm or 0.05 mm. 
     The toner cartridge  18  includes a locking mechanism that locks the toner cartridge  18  to the image forming apparatus in interlocked relation with the rotation of the knob  35 . 
       FIG. 12  illustrates the curved guides  37  in the shape of a short cylinder. The curved guides  37  may also be in the shape of a short cylinder. However, a short cylindrical guide  37  has high rigidity and therefore may be difficult to deform when the projections  31  abuts the projection  30  during rotation of the shutter  29  relative to the housing  28 . Thus, the short cylindrical guide  37  is difficult to vibrate with sufficient amplitude during rotation of the shutter  29 . If the projection  31  formed on the short cylindrical guide  37  are small, the amplitude of vibration is also small. Therefore, the curved guides  37  are preferably in the shape of a partial ring or an arc rather than in the shape of a substantial short cylinder. In order to generate vibration, at least one projection  31  needs to be formed on at least one of the curved guides  37 . However, one or more of the projections  31  should be formed on one or more of the curved guides  37  for a sufficient amount of vibration. 
     {Locking Mechanism} 
     The locking mechanism for locking the toner cartridge  18  to the process cartridge  2  will be described with reference to  FIGS. 13 ,  14 , and  15 A- 15 C. 
       FIG. 13  is a perspective view illustrating a pertinent portion of the locking mechanism on the process cartridge side. 
       FIG. 14  is a perspective view of a pertinent portion of the locking mechanism on the toner cartridge side. 
       FIG. 15A  is a front view of the toner cartridge  18  before the toner cartridge  18  is attached to the process cartridge  2 . 
       FIG. 15B  is a front view of the toner cartridge  18  shortly after the toner cartridge  18  has been attached to the process cartridge  2 . 
       FIG. 15C  is a front view of the toner cartridge  18  when the knob  35  has been rotated from the position shown in  FIG. 15B  to the opening position (i.e., locking position). 
     Referring to  FIG. 13 , a plate-like guide projection  43  is formed on the inner wall surface of the process cartridge  2  and extends in a longitudinal direction. When the toner cartridge  18  is attached to the process cartridge  2 , the guide projection  43  enters the toner cartridge  18  such that the toner cartridge  18  is guided into the process cartridge  2  in the correct orientation. The knob  35  includes two pairs of guide walls, each pair including a guide wall  44  and a guide wall  45  contiguous with the guide wall  44  to form an obtuse angle θ therebetween. The two pairs are arranged at one longitudinal end of the shutter  29  such that they are diametrically opposite to each other. The guide walls  44  define a gap  40   a  therebetween and the guide walls  45  define a gap  40   b  therebetween as shown in  FIG. 15A . The knob  35  includes an opening  40   c  ( FIG. 14 ) between a hook  46  and one of the guide walls  44 . As a user lowers the toner cartridge  18  into the process cartridge  2  from above, the guide projection  43  enters the gap  40   a  through the opening  40   c  to guide the toner cartridge  18  into the process cartridge  2 . In this manner, the toner cartridge  18  may be placed in position. 
     When the knob  35  is rotated in a direction shown by arrow A in  FIG. 15B  after the toner cartridge  18  has been placed in position, the user operates the knob  35  to rotate the shutter  29  relative to the housing  28 , so that the guide walls  44  rotate away from the guide projection  43 . As the knob  35  rotates, a locking hook  46  enters under the guide projection  43  while the shutter portion  36  gradually opening the outlet  34 . Further rotating the knob  35  causes the guide walls  45  to abut the guide projection  43  so that the shutter  29  cannot rotate any further. 
     When the guide walls  45  abut the guide projection  43  to prevent further rotation of the shutter  29 , the opening  38  becomes aligned with the outlet  34 . The locking hook  46  engages the guide projection  43  to fix the toner cartridge  18  with respect to the process cartridge  2 . When the toner cartridge  18  is to be detached from the process cartridge  2 , the aforementioned procedure is reversed. The user first operates the knob  35  to the closing position. In other words, the user rotates the knob  35  in a direction shown by arrow B in  FIG. 15C  until the knob  35  cannot rotate any further, and then pulls the entire toner cartridge  18  upward, thereby taking the toner cartridge  18  out of the process cartridge  2 . 
       FIG. 16A  is a cross sectional view of the toner cartridge  18  and the process cartridge  2  shortly after the toner cartridge  18  has been attached to the process cartridge  2 . 
       FIG. 16B  is a cross sectional view of the toner cartridge  18  and the process cartridge  2  when the knob  35  is operated toward the opening position, but is stopped shortly before the discharging outlet  34  is opened. 
       FIG. 16C  is a cross sectional view of the toner cartridge  18  and the process cartridge  2  when the knob  35  is operated to the opening position so that the discharging outlet  34  is opened completely. 
     Referring to  FIG. 16A , the toner cartridge  18  has been attached to the process cartridge  2  so that the outlet  34  formed in the housing  28  is in alignment with the inlet  41  formed in the process cartridge  2 . The shutter portion  36  is at the closing position before the toner  32  is discharged into the process cartridge  2 , i.e., the shutter portion  36  faces the outlet  34  formed in the bottom wall of the toner cartridge  18 , and therefore the toner chamber  19  is full of the fresh toner  32 . 
     Referring to  FIG. 16B , rotating the knob  35  in the A direction, the shutter portion  36  rotates in sliding contact with the inner surface of the housing  28 , gradually opening the outlet  34  to discharge the fresh toner  32  into the toner reservoir  20 . At the same time, the locking hook  46  enters under the guide projection  43  to lock the toner cartridge  18  to the process cartridge  2 . 
     When the curved guides  37  slide on the rib  30 , the rib  30  interferes with the projections  31  so that rib  30  exerts an increased force against the projections  31 . As the user further rotates the knob  35  to overcome the increased force, the curved guides  37  is caused to temporarily deform until the rib  30  takes up a position between adjacent projections  31  formed on each of the curved guides  37 . As a result, the shutter  29  is subjected to a short vibration. 
     Because the rib  30  interferes with a plurality of projections  31  formed on the outer curved surface  37   a  of the curved guides  37 , both the shutter  29  and the housing  28  experience a series of short vibrations. The series of short vibrations effectively shakes the toner off various portions of the toner cartridge  18 , including the inner wall of the housing  28 , upper corners of the housing  28 , and outer curved surface  37   a  of the curved guides  37 . This operation reduces the amount of toner  32  that would otherwise remain in the toner chamber  19  after discharging the toner  32  into the process cartridge  2 . 
     Rotating the knob  35  in the B direction causes the shutter portion  36  to start closing the outlet  34 , causes the shutter portion  36  to gradually cease the supply of the toner  32  into the process cartridge  2 , and causes the locking hook  46  to start exiting from under the guide projection  43 . 
     Referring to  FIG. 16C , when the knob  35  has been rotated in the A direction completely, the opening  38  is in alignment with the outlet  34 , i.e., the discharging outlet  34  has been opened completely. Thus, the toner  32  is supplied from the toner chamber  19  into the toner reservoir  20 , and the locking mechanism locks the toner cartridge  18  to the process cartridge  2  completely. 
     Prior to replacement of the toner cartridge  18  by a new, unused one, the knob  35  is rotated completely in the B direction so that the shutter portion  36  completely closes the outlet  34  and the locking mechanism causes the toner cartridge  18  to be unlocked from the process cartridge  2 . Then, the toner cartridge  18  may be taken out of the process cartridge  2 . 
     The toner cartridge  18  includes rib-shaped portions at various locations inside the housing  28 , and the toner is apt to remain on or adhere to the rib-like portions. In order to effectively reduce residual toner remaining in the toner cartridge  18 , it is desirable to configure the toner cartridge  18  such that the rib-like portions vibrate with large amplitudes. The structure of the embodiment effectively generates large amplitudes of vibration of the rib-like portions, preventing the toner  32  from remaining within the toner cartridge  18 . 
     Modification to the First Embodiment 
       FIG. 17  illustrates a modification to the shape of the recess  33 . Referring to  FIG. 17 , the recess  33  has a rectangular cross section. Dimensions L 4  and L 5  are related such that L 5 &gt;L 4 . 
       FIG. 18  illustrates another modification to the shape of the recess  33 . Referring to  FIG. 18 , the recess  33  has a cross section in the shape of a saw-tooth. Dimensions L 6  and L 7  are related such that L 7 &gt;L 6 . 
       FIG. 19  illustrates a modification to the shape of the rib  30 . Referring to  FIG. 19 , the rib  30  has a recess  30   d  formed in the flat surface  30   a.    
       FIG. 20  is an enlarged view of the recess  30   d . The recess has a cross section of a trapezoid with side walls  30   e  and  30   f . The side walls  30   e  and  30   f  are substantially parallel to the side surfaces  30   c  and  30   b , respectively. 
       FIG. 21  illustrates a yet another modification in which the housing  28  has a recess  47  formed in the inner wall surface of the housing  28 . 
     Second Embodiment 
     A second embodiment differs from the first embodiment in that curved guides  37  have recesses  33  formed in their outer curved surfaces  37   a.    
     The first and second embodiments are substantially the same in the configuration of the image forming apparatus and the process cartridge  2 . 
       FIG. 22  is a partial perspective view of a housing  28  shown in  FIG. 6  with a part of the housing  28  cut away.  FIG. 23  is an enlarged view of a portion E of  FIG. 22 .  FIG. 24  is a cross-sectional view of the toner cartridge  18 .  FIG. 25  is an enlarged cross-sectional view of a portion F of  FIG. 24  when a knob  35  shown in  FIG. 24  is being rotated in a direction shown by arrow A. 
     Referring to  FIG. 22 , a projection  30  is formed on an inner surface of the housing  28 , and extends in a longitudinal direction of the housing  28 . The projection  30  also extends toward the curved guides  37  of a shutter  29 . The curved guides  37  are in the shape of a partial ring or an arc such that the outer curved surfaces  37   a  lie substantially in a cylindrical plane in which the outer surface of a shutter portion  36  lies. 
     The shutter  29  includes the shutter portion  36 . When the shutter  29  rotates in sliding contact with the housing  28 , the shutter portion  36  opens or closes an outlet  34  formed in the housing  28 . The knob  35  is formed at a longitudinal end of the toner cartridge  18 , and is in one piece with the shutter  29  or is assembled to the shutter  29  securely. Operating the rotary knob  35  to an opening position causes the shutter portion  36  to open an outlet  34  formed in the housing  28 , allowing toner  32  to be supplied into the toner reservoir  20  of the process cartridge  2 . Operating the knob  35  to a closing position causes the shutter portion  36  to close the outlet  34 , ceasing to supply the toner  32  into the toner reservoir  20  as well as locking the toner cartridge  18  to the process cartridge  2 . 
     The recesses  33  are formed in the outer curved surfaces  37   a  of the curved guides  37 . The recesses  33  have a substantially semi-circular cross section, and extend in directions parallel to a rib  30  ( FIG. 22 ) formed on an upper inner surface of the rectangular parallelpiped upper half  28   b  of the toner cartridge  18 . At least one recess  33  needs to be formed in at least one of the curved guides  37 . However, more of the recesses  33  should be formed in more of the curved surfaces  37   a  of the curved guides  37  for sufficient vibration. 
     The rib  30  includes a flat surface  30   a  and side surfaces  30   b  and  30   c  contiguous to the flat surface  30   a . The side surfaces  30   b  and  30   c  form a tapered portion of the rib  30  ( FIG. 25 ). The recesses  33  have a substantially semicircular cross section. As the shutter  29  rotates relative to the housing  28 , the curved surfaces  37   a  slide on the rib  30 . When the rib  30  presses the curved surfaces  37   a  down, the curved guide  37  deforms such that when the shutter  29  rotates relative to the housing  28 , the edge of the recess  33  interferes with the edge of the rib  30  at which the flat surface  30   a  and the side surface  30   c  or  30   b  intersect. The interference of the edge of the recess  33  with the edge of the rib  30  causes the curved guide  37  to resiliently deform and then to disengage from the rib  30 . The side surfaces  30   b  help the rib  30  exit the recess  33 . Shortly after the rib  30  disengages from the edge of the recess  33 , the curved guide  37  is released from the rib  30  to vibrate due to abrupt disengagement of the recess  33  from the rib  30 . The shape and dimension of the rib  30  may be the same as those described in the first embodiment. 
     The flat surface  30   a  of the projection  30  includes a dimension L 4  in a direction of rotation of the curved guide  37 . The recesses  33  are spaced apart by a distance L 6 , which is longer than the dimension L 4  of the flat surface  30   a . Thus, when the shutter  29  rotates, the rib  30  will not extend over two adjacent recesses  33  simultaneously at any moment, thereby generating a sufficient amount of vibration of the shutter  29 . 
     A description will be given of a portion of the second embodiment different from the first embodiment. Just as shown in  FIG. 16B , operating the knob  35  in the A direction causes the shutter  29  to rotate relative to the housing  28 , so that the shutter portion  36  gradually opens the outlet  34 . This allows the toner  32  to be supplied gradually from the toner cartridge  18  into the toner reservoir  20  of the process cartridge  2 . At the same time, a locking hook  46  ( FIG. 14 ) gradually enters under a guide projection  43  to lock the toner cartridge  18  to the process cartridge  2 . 
     When the curved guide  37  slides on the rib  30 , the rib  30  interferes with the recess  33  to exert a force against the recess  33 . As the user further rotates the knob  35  to overcome the force, the curved guide  37  is caused to resiliently deform until the rib  30  takes up a position between adjacent recesses  33  formed in each of the curved guides  37 . As a result, the shutter  29  is subjected to a short vibration. 
     The rib  30  interferes with a plurality of recesses  33  formed in the outer curved surfaces  37   a  of the curved guides  37 , both the shutter  29  and the housing  28  experience a series of short vibrations during rotation of the shutter  29 . The series of short vibrations effectively shakes the toner  32  off various portions including the inner surface of the housing  28 , upper corners of the housing  28 , and outer curved surface  37   a  of the curved guides  37 . This operation reduces the amount of the toner  32  that would otherwise remain in a toner chamber  19  after discharging the toner  32  into the process cartridge  2 . 
     The second embodiment has been described with respect to a combination of the shutter  29  having curved guides  37  with the recesses  33  formed therein, and the housing  28  having the projection  30 . The invention may be modified such that projections are formed in the curved guides  37  and recesses are formed in the inner surface of the housing  28 . 
       FIG. 26  illustrates a modification to the shape of the rib  30 . Referring to  FIG. 26 , the rib  30  includes a projection  30   g  having a substantially semicircular cross section. The projection  30   g  and recesses  33  extend substantially in a longitudinal direction of the toner cartridge  18 . 
     While the first and second embodiments have been described in terms of a toner cartridge detachably mounted to a process cartridge into which a developer is supplied from the toner cartridge, the invention may also the applicable to electrophotographic apparatuses including printers, facsimile machines, and multifunction printers. The developer material container of the invention may be applied to developing apparatuses including a developing device in which a toner container and a developing section are of a unit type, and a developer container that collects residual developer remaining on an image bearing body and an image-transferring mechanism. Such a developer container includes a developer chamber, an outlet through which the developer material is discharged, and a shutter member capable of opening and closing the outlet. 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art intended to be included within the scope of the following claims.