CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority from Japanese Patent Application No. 2016-070707 filed on Mar. 31, 2016, the content of which is incorporated herein by reference in its entirety. 
       FIELD OF DISCLOSURE 
       [0002]    Aspects disclosed herein relate to a developing cartridge including a developer bag in a housing thereof. 
       BACKGROUND 
       [0003]    A known developing cartridge includes a bag-like developer container (hereinafter, referred to as a “developer bag”) within its housing. The developer bag stores a developer therein. The developer bag has an outlet for releasing the developer therethrough. The outlet is closed by a film-like seal member to seal the developer bag. The seal member is fixed to a shaft of an agitator, and is removed or peeled from the developer bag by rotation of the agitator. The removal of the seal member thus allows the developer to flow from the developer bag through the outlet. 
       SUMMARY 
       [0004]    Nevertheless, in the known art, the developer bag that has become empty of the developer may remain inside the developing cartridge. The developer bag remaining inside the developing cartridge may obstruct agitation or supply of the developer. 
         [0005]    According to the one or more aspects of the disclosure, a developing cartridge may include a developing roller, a developer bag, a housing, and a shaft. The developer bag may store a developer therein. The housing may include a developer storage chamber accommodating the developer bag therein. The housing may support the developing roller. The shaft may be fixed to the developer bag and movable to pull the developer bag theretoward. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    Aspects of the disclosure are illustrated by way of example and not by limitation in the accompanying figures in which like reference characters indicate similar elements. 
           [0007]      FIG. 1  is a sectional view illustrating a developing cartridge when viewed in a direction in which a rotation axis of an agitator extends in an illustrative embodiment according to one or more aspects of the disclosure. 
           [0008]      FIG. 2  is a vertical sectional view illustrating the developing cartridge in the illustrative embodiment according to one or more aspects of the disclosure. 
           [0009]      FIG. 3A  is an external perspective view illustrating a developer bag in the illustrative embodiment according to one or more aspects of the disclosure. 
           [0010]      FIG. 3B  is a sectional view illustrating a portion of the developer bag where an upper portion and a lower portion are bonded to each other in the illustrative embodiment according to one or more aspects of the disclosure. 
           [0011]      FIG. 4A  illustrates how the developer bag is opened in the illustrative embodiment according to one or more aspects of the disclosure. 
           [0012]      FIG. 4B  illustrates how a developer is released from the opened developer bag in the illustrative embodiment according to one or more aspects of the disclosure. 
           [0013]      FIG. 5  illustrates a developing cartridge in a first alternative embodiment according to one or more aspects of the disclosure. 
           [0014]      FIG. 6  illustrates a developer bag in a second alternative embodiment according to one or more aspects of the disclosure. 
           [0015]      FIG. 7A  illustrates a developing cartridge in a third alternative embodiment according to one or more aspects of the disclosure. 
           [0016]      FIG. 7B  illustrates how a developer is released from an opened developer bag in the third alternative embodiment according to one or more aspects of the disclosure. 
           [0017]      FIG. 8  illustrates a developing cartridge in a fourth alternative embodiment according to one or more aspects of the disclosure. 
           [0018]      FIG. 9A  is an enlarged view illustrating a waste bag storage portion and its surrounding components in a fifth alternative embodiment according to one or more aspects of the disclosure. 
           [0019]      FIG. 9B  is an enlarged view illustrating a waste bag storage portion and its surrounding components in a sixth alternative embodiment according to one or more aspects of the disclosure. 
           [0020]      FIG. 9C  is an enlarged view illustrating a waste bag storage portion and its surrounding components in a seventh alternative embodiment according to one or more aspects of the disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    Hereinafter, an illustrative embodiment will be described with reference to the accompanying drawings. 
         [0022]    As illustrated in  FIG. 1 , a developing cartridge  1  includes a housing  2 , a developing roller  3 , a supply roller  4 , a layer-thickness regulating blade  5 , an agitator  7 , a developer bag  20 , and a winding shaft  11  (as an example of a shaft). The developer bag  20  may store toner T (as an example of a developer) therein. The winding shaft  11  is fixed to the developer bag  20 , and movable to pull the developer bag and wind the developer bag therearound. 
         [0023]    The developing roller  3  is rotatably supported by the housing  2 . The developing roller  3  is disposed in contact with or near to a photosensitive drum  6 . 
         [0024]    The supply roller  4  is disposed in contact with the developing roller  3 . The supply roller  4  is configured to supply a developer to the developing roller  3 . The supply roller  4  is rotatably supported by the housing  2 . 
         [0025]    The layer-thickness regulating blade  5  has one end that is supported by the housing  2 , and the other end that is positioned in contact with the developing roller  3 . 
         [0026]    The developer bag  20  includes a bag portion  21  and a connecting portion  22 . The bag portion  21  stores toner T therein. The connecting portion  22  has one end that is connected to the bag portion  21 , and the other end that is connected to the winding shaft  11 . The developer bag  20  includes a bonded portion that may be a portion of the developer bag  20 . The developer bag  20  is sealed at the bonded portion to close an outlet for releasing toner T stored therein. The bonded portion is positioned at an end portion of the bag portion  21  to which the connecting portion  22  of the developer bag  20  is connected. The bonded portion is configured to separate from the end portion of the bag portion  21  by contact of the bag portion  21  to a squeeze portion  15 . 
         [0027]    The winding shaft  11  is rotatably supported by the housing  2 . The winding shaft  11  is disposed opposite to the developing roller  3  across the agitator  7 . The winding shaft  11  is disposed outside or out of a rotation path K of the agitator  7  within the housing  2 . The winding shaft  11  is configured to rotate in a direction to wind the developer bag  20  therearound from below, e.g., in a counterclockwise direction in  FIG. 1 . 
         [0028]    The housing  2  includes a developer storage chamber  12 , a waste bag storage portion  13 , a handle  14 , and the squeeze portion  15 . The developer storage chamber  12  accommodates the developer bag  20  therein. The waste bag storage portion  13  is configured to store the developer bag  20  that has wound around the winding shaft  11 . 
         [0029]    The waste bag storage portion  13  protrudes outwardly relative to the developer storage chamber  12  in the housing  2 . The winding shaft  11  is disposed in the waste bag storage portion  13 . The waste bag storage portion  13  has a lower wall  13 A below the winding shaft  11 . The lower wall  13 A is downwardly inclined toward the developer storage chamber  12 . The lower wall  13 A is contiguous to inner wall surfaces defining the developer storage chamber  12  of the housing  2 . The entire portion of the lower wall  13 A is downwardly inclined toward the developer storage chamber  12 . The waste bag storage portion  13  has a relatively wide open entrance and is tapered toward the back from the entrance when viewed in a direction in which a rotation axis of the winding shaft  11  extends (i.e., the height of the waste bag storage portion  13  decreases gradually toward the back in  FIG. 1 ). That is, the entrance of the waste bag storage portion  13  has the largest height. A lower end of the lower wall  13 A is spaced from the squeeze portion  15 . 
         [0030]    The handle  14  extends from an outer surface of the housing  2  and is a one piece with the housing  2 . The handle  14  is disposed near the winding shaft  11  rather than the developing roller  3 . 
         [0031]    The squeeze portion  15  includes a first portion  15 A, and a second portion  15 B that is spaced from the first portion  15 A by a predetermined distance. The squeeze portion  15  is disposed between the waste bag storage portion  13  and the bag portion  21  of the developer bag  20  that has not been wound around the winding shaft  11 . In the illustrative embodiment, for example, the squeeze portion  15  is positioned at the entrance of the waste bag storage portion  13 . A clearance between the first portion  15 A and the second portion  15 B, i.e., a height of an opening of the squeeze portion  15 , is smaller than a maximum height of the waste bag storage portion  13  in a direction in which the first portion  15 A and the second portion  15 B face each other. The clearance between the first portion  15 A and the second portion  15 B is greater than a thickness of the developer bag  20  that has released toner T completely therefrom. For example, the clearance between the first portion  15 A and the second portion  15 B may be equal to a thickness of a sheet member for the developer bag  20  plus 3 mm or less, preferably 2 mm or less, more preferably 1 mm or less. 
         [0032]    The first portion  15 A protrudes from an inner surface of an upper wall  2 A of the housing  2 . The first portion  15 A has a substantially rectangular shape when viewed in the axial direction of the winding shaft  11 . The second portion  15 B is a one piece with the housing  2 . The second portion  15 B has a substantially triangular shape when viewed in the axial direction of the winding shaft  11 . The second portion  15 B has corners, one of which is an acute corner  15 C situated on a farther side from the winding shaft  11  in a direction in which the squeeze portion  15  and the winding shaft  11  face each other. The connecting portion  22  of the developer bag  20  is connected to the winding shaft  11  while being positioned between the first portion  15 A and the second portion  15 B. In this state, the connecting portion  22  connects between the bag portion  21  and the winding shaft  11 . 
         [0033]    The agitator  7  may be a deformable sheet-shaped member. The agitator  7  is rotatably supported by the housing  2 . 
         [0034]    As illustrated in  FIG. 2 , the agitator  7  is rotatably supported by the housing  2  via a rotating shaft  7 A. The rotating shaft  7 A has one end portion that is rotatably supported by a first bearing  19 A that may be a recess defined by inner wall surfaces of the housing  2 . The rotating shaft  7 A has the other end portion that is rotatably supported by a second bearing  19 B of the housing  2 . The other end portion of the rotating shaft  7 A extends to the outside of the housing  2 . A first gear  16  is fixed to the exposed end of the rotating shaft  7 A. The first gear  16  is configured to transmit a driving force to the rotating shaft  7 A from a motor (not illustrated) as a drive source. The first gear  16  is in mesh with a second gear  17  rotatably supported by the housing  2 . 
         [0035]    The winding shaft  11  extends in a direction along a direction in which a rotation axis of the agitator  7  extends. The winding shaft  11  has one end portion that is rotatably supported by a third bearing  19 C that may be a recess defined by inner wall surfaces of the housing  2 . The winding shaft  11  has the other end portion that is rotatably supported by a fourth bearing  19 D of the housing  2 . The other end portion of the winding shaft  11  extends to the outside of the housing  2 . A third gear  18  is fixed to the exposed end of the winding shaft  11 . The third gear  18  is in mesh with the second gear  17 . The third gear  18  is configured to transmit a driving force received from the drive source via the first gear  16  and the second gear  17  to the winding shaft  11 . 
         [0036]    As illustrated in  FIG. 3A , the developer bag  20  including the bag portion  21  and the connecting portion  22  is formed by a folded sheet member. The sheet member is folded to make a crease  21 C, and edge portions of the overlapping portions are bonded to each other using an adhesive B. By doing so, such a developer bag  20  may be formed. The bag portion  21  includes an upper portion  21 A and a lower portion  21 B that are contiguous to each other via the crease  21 C. The upper portion  21 A is bonded to the lower portion  21 B at three sides (e.g., edge portions  21 D) other than the crease  21 C. 
         [0037]    As illustrated in  FIG. 3B , an end portion  21 E of the lower portion  21 B situated close to the connecting portion  22  is folded back toward the inside of the bag portion  21 . The end portion  21 E has a surface  21 F (e.g., an upper surface in  FIG. 3B ) that extends contiguously from an external surface of the lower portion  21 B. The surface  21 F of the end portion  21 E is bonded to a lower surface of the upper portion  21 A by an adhesive B. The portion (e.g., the surface  21 F) of the end portion  21 E bonded to the upper portion  21 A using the adhesive B may be a bonded portion where a portion of the developer bag  20  is bonded to another portion of the developer bag  20  to close the outlet for releasing toner T stored in the developer bag  20  therefrom. The bonded portion is positioned at the end portion of the bag portion  21  where the connection portion  22  is connected to. The bonded portion is configured to separate from the lower surface of the upper portion  21 A by contact of the bag portion  21  and the squeeze portion  15 . 
         [0038]    The sheet member used for the developer bag  20  may be made of metallic materials, e.g., aluminum, or resin materials, e.g., polyethylene terephthalate (“PET”), polyethylene (“PE”), or polypropylene (“PP). 
         [0039]    Hereinafter, an explanation will be made on how the developing cartridge  1  operates when it is used in an image forming apparatus. 
         [0040]    As illustrated in  FIG. 4A , in response to rotation of the agitator  7  by a driving force from the drive source, the winding shaft  11  rotates counterclockwise in synchronization with the rotation of the agitator  7 . As the winding shaft  11  starts rotating, the connecting portion  22  fixed to the winding shaft  11  is wound around the winding shaft  11  from below. Thus, the bag portion  21  is pulled toward the winding shaft  11  to contact the squeeze portion  15 . At that time, the corner  15 C of the second portion  15 B strongly contacts the vicinity of the end portion  21 E of the bag portion  21  to remove the end portion  21 E from the upper portion  21 A downward. Thus, in the developer bag  20 , the bonded portion separates from the upper portion  21 A and therefore the outlet (as an example of an opening) for releasing toner T from the developer bag  20  to the developer storage chamber  12  appears. 
         [0041]    As illustrated in  FIG. 4B , as the winding shaft  11  further rotates counterclockwise, the winding shaft  11  rolls up the connecting portion  22  and the bag portion  21 , and the squeeze portion  15  squeezes toner T from the bag portion  21 . At that time, the bag portion  21  widely opens by separation of the lower portion  21 B from the upper portion  21 A by weight of toner T. Thus, toner T is allowed to flow to the developer storage chamber  12  from the bag portion  21 . 
         [0042]    When the winding shaft  11  further rotates counterclockwise, toner T 1  adhering to the interior surface of the bag portion  21  is scraped by the squeeze portion  15 . As the lower portion  21 B separates from the upper portion  21 A completely, the developer bag  20  returns to a sheet member. An entire portion of the developer bag  20  is then wound around the winding shaft  11  and removed from the developer storage chamber  12 . The developer bag  20  wound around the winding shaft  11  is compactly stored in the waste bag storage portion  13  in a rolled manner. After the developer bag  20  has completely wound, the rotation of the winding shaft  11  may be stopped by disengagement of the second gear  17  and the third gear  18 . 
         [0043]    Toner T released to the developer storage chamber  12  is supplied to the supply roller  4 . The supply roller  4  then supplies toner T to the developing roller  3  by rotating in contact with the developing roller  3 . The layer-thickness regulating blade  5  regulates a layer thickness of toner T held by the developing roller  3 . Thereafter, toner T is supplied onto a circumferential surface of the photosensitive drum  6 . 
         [0044]    While the developing cartridge  1  is in operation, some (T 2 ) of toner T may intrude into the waste bag storage portion  13 . Nevertheless, the intruding toner T 2  slides down the inclined lower wall  13 A to return to the developer storage chamber  12 . 
         [0045]    According to the illustrative embodiment, the following effects may be obtained. 
         [0046]    The sealed developer bag  20  is opened by first rotation of the winding shaft  11  disposed in the housing  2 . Therefore, the developer bag  20  may be sealed to store toner T therein until first use of the developing cartridge  1 . That is, toner T may be released from the developer bag  20  at the first use of the developing cartridge  1 . Thus, this configuration may eliminate a user&#39;s operation for opening the developer bag  20  when the developing cartridge  1  is first used, and may also reduce or prevent leakage of toner T to the outside of the housing  2 . In addition, toner T is stored in the sealed developer bag  20  until immediately before the developing cartridge  1  is first used, which may reduce deterioration of toner T. Therefore, toner T may have a long use life. 
         [0047]    While the developer bag  20  passes through the narrow clearance (e.g., the narrow opening) in the squeeze portion  15 , toner T may be squeezed out from the developer bag  20 . While the developer bag  20  passes therethrough, toner T adhering to the interior surface of the developer bag  20  may also be scraped therefrom. Therefore, this configuration may minimize residual toner T on the interior surface of the developer bag  20 . Providing the squeeze portion  15  at the entrance of the waste bag storage portion  13  may enable the rolled developer bag  20  to be kept in the waste bag storage portion  13  without allowing the developer bag  20  to return to the developer storage chamber  12 . 
         [0048]    The winding shaft  11  is disposed outside or out of the rotation path K of the agitator  7 . Therefore, the winding shaft  11  may fail to interfere with the agitator  7 . The developer bag  20  wound around the winding shaft  11  may also fail to interfere with the agitator  7 . Therefore, toner T released to and stored in the developer storage chamber  12  may be agitated by the agitator  7  and supplied to the developing roller  3  by the agitator  7  effectively. 
         [0049]    The winding shaft  11  is disposed opposite to the developing roller  3  across the agitator  7 . With this configuration, the developer bag  20  wound around the winding shaft  11  may fail to interfere with the developing roller  3  and the supply roller  4  adjacent to the developing roller  3 . Therefore, toner T released to and stored in the developer storage chamber  12  may be supplied to the developing roller  3  effectively. 
         [0050]    The waste bag storage portion  13  protrudes outwardly relative to the developer storage chamber  12  in the housing  2 . With this configuration, the rolled developer bag  20  stored in the waste bag storage portion  13  may fail to interfere with operation by the agitator  7 , such as agitation of toner T by the agitator  7  or supply of toner T to the developing roller  3  by the agitator  7 . 
         [0051]    The developer bag  20  returns to the sheet member after completely releasing toner T therefrom. Therefore, the winding shaft  11  may roll up the developer bag  20  compactly, and toner T remaining on the interior surface of the developer bag  20  may be reduced to a minimum. In addition, toner T adhering the interior surface of the developer bag  20  (e.g., the sheet member) may be scraped therefrom by the squeeze portion  15 . 
         [0052]    The developer bag  20  is wound around the winding shaft  11  from below. With this configuration, when the winding shaft  11  rolls up the developer bag  20  therearound, toner T may be removed from the lower surface (e.g., the interior surface) of the upper portion  21 A of the bag portion  21  at the squeeze portion  15 . Thus, the developer bag  20  may be wound with minimum toner T remaining thereto. 
         [0053]    When the developer bag  20  is being opened, the end portion  21 E of the lower portion  21 B is gradually peeled from the upper portion  21 A, which may enable a force of pulling the developer bag  20  to be smaller. Therefore, this configuration may further enable a driving force of the drive source to be smaller. 
         [0054]    The handle  14  is disposed near the winding shaft  11  rather than the developing roller  3 . Therefore, when the user attaches or detaches the developing cartridge  1  to or from the image forming apparatus by holding the handle  14 , this configuration may eliminate an accidental touch to the developing roller  3  by the user. 
         [0055]    While the disclosure has been described in detail with reference to the specific embodiment thereof, this is merely an example, and various changes, arrangements and modifications may be applied therein without departing from the spirit and scope of the disclosure. Hereinafter, the disclosure will be further described with reference to alternative embodiments. An explanation will be given mainly for the parts different from the illustrative embodiment, and an explanation will be omitted for the common components by assigning the same reference numerals thereto. 
       First Alternative Embodiment 
       [0056]    In the illustrative embodiment, the waste bag storage portion  13  protrudes horizontally relative to the developer storage chamber  12  in the housing  2 . Nevertheless, in other embodiments, for example, a bag storage portion may protrude vertically (e.g., upward) relative to the developer storage chamber in the housing. 
         [0057]    As illustrated in  FIG. 5 , in a first alternative embodiment, for example, a developing cartridge  30  includes a bag storage portion  31  protruding upward relative to the developer storage chamber  12  in the housing  2 . The winding shaft  11  is disposed in the upwardly-protruding waste bag storage portion  31 . A squeeze portion  35  including a first portion  35 A and a second portion  35 B is disposed below the winding shaft  11 . The first portion  35 A and the second portion  35 B each have a triangular shape when viewed in direction in which the rotation axis of the winding shaft  11  extends. The first portion  35 A and the second portion  35 B each have an inclined upper surface. The waste bag storage portion  31  has no partition (e.g., a lower wall) for dividing the waste bag storage portion  31  and the developer storage chamber  12 . 
         [0058]    According to the first alternative embodiment, this configuration may also enable release of toner T from the developer bag  20  within the developing cartridge  30  and storage of the rolled developer bag  20  in the waste bag storage portion  31 . According to the first alternative embodiment, the waste bag storage portion  31  protrudes upward and has no lower wall. Therefore, toner T intruding the waste bag storage portion  31  may fall down to return to the developer storage chamber  12 . Further, each of the first portion  35 A and the second portion  35 B of the squeeze portion  35  has the inclined upper surface. This configuration may reduce accumulation of toner T falling on the first portion  35 A and the second portion  35 B from the waste bag storage portion  31 . 
       Second Alternative Embodiment 
       [0059]    In the illustrative embodiment, the developer bag  20  is opened by peeling off the bonded portion bonded using the adhesive B. Nevertheless, in other embodiments, for example, a developer bag may have an easy-to-tear portion at which the developer bag may tear easily as compared with the other portions thereof. 
         [0060]    As illustrated in  FIG. 6 , in a second alternative embodiment, for example, a developer bag  40  includes a bag portion  41  storing toner T therein, and a connecting portion  42  connecting between the winding shaft  11  and the bag portion  41 . The bag portion  41  includes a cylindrical portion  41 A and side portions  41 B. The side portions  41 B close ends of the cylindrical portion  41 A. The bag portion  41  has first perforations  43  and second perforations  44 , which are an example of the easy-to-tear portion. The first perforations  43  align along an end portion of the bag portion  41  where the connecting portion  42  is connected to. The second perforations  44  extend from each end of the line of the first perforations  43  and align along a circumferential direction of the cylindrical portion  41 A. 
         [0061]    According to the second alternative embodiment, this configuration may also enable the bag portion  41  to be opened to release toner T therefrom in response to winding of the developer bag  40  around the winding shaft  11  (not illustrated in  FIG. 6 ). More specifically, the bag portion  41  is torn at the first perforations  43  to release toner T therefrom by contact of the first perforations  43  to the squeeze portion  15  in response to winding of the developer bag  40  around the winding shaft  11 . 
       Third Alternative Embodiment 
       [0062]    In the illustrative embodiment, the squeeze portion  15  opens the developer bag  20  by removing a portion (e.g., the bonded portion) of the developer bag  20  from another portion thereof. Nevertheless, in other embodiments, for example, a developer bag may have an outlet for releasing a developer and a developing cartridge may further include a seal member for closing the outlet. In this configuration, the developer bag may be opened by removing the seal member from the outlet. 
         [0063]    As illustrated in  FIG. 7A , in a third alternative embodiment, for example, a developing cartridge  50  includes a developer bag  51  having an outlet  51 A, a seal member  52 , and the squeeze portion  15 . The seal member  52  has one end portion that closes the outlet  51 A to seal the developer bag  51 , and the other end portion that is fixed to one of the inner surfaces of the housing  2  of the developing cartridge  50 . The adhesive strength of the other end portion to the inner surface of the housing  2  is stronger than the adhesive strength of the one end portion to the developer bag  51 . 
         [0064]    As illustrated in  FIG. 7B , as the winding shaft  11  rotates, the winding shaft  11  pulls the developer bag  51  to remove the seal member  52  from the developer bag  51  to reveal the outlet  51 A. In response to removal of the seal member  52 , the outlet  51 A becomes exposed and thus toner T is released to the developer storage chamber  12 . The developer bag  51  is wound around the winding shaft  11  while an upper portion  51 B and a lower portion  51 C of the developer bag  51  pass between the first portion  15 A and the second portion  15 B of the squeeze portion  15  simultaneously. Thus, the developer bag  51  is squeezed by the squeeze portion  15  to release toner T therefrom. According to the third alternative embodiment, this configuration may also enable the bag portion  51  to be opened to release toner T therefrom by rotation of the winding shaft  11 . In this configuration, the developer bag  51  that has released toner T therefrom completely is also wound around the winding shaft  11 . Therefore, the waste developer bag  51  may fail to interfere with operation by the agitator  7 , such as agitation of toner T by the agitator  7  or supply of toner T to the developing roller  3  by the agitator  7 . 
       Fourth Alternative Embodiment 
       [0065]    In the illustrative embodiment, the winding shaft  11  extends along the direction in which the rotating shaft  7 A of the agitator  7  extends. Nevertheless, in other embodiments, for example, a winding shaft may extend in a direction orthogonal to the direction in which the rotating shaft of the agitator extends. 
         [0066]    As illustrated in  FIG. 8 , in a fourth alternative embodiment, for example, a developing cartridge  60  includes a winding shaft  61  that extends in a direction orthogonal to a rotating axis L of the agitator  7 . The developer bag  65  is connected to the winding shaft  61 . According to the fourth alternative embodiment, this configuration may also enable the winding shaft  61  to roll up the developer bag  65  that has released toner T therefrom completely. Therefore, the rolled developer bag  65  may fail to interfere with operation of the developing cartridge  60 . 
       Fifth Alternative Embodiment 
       [0067]    In the illustrative embodiment, the squeeze portion  15  has the opening (e.g., the clearance between the first portion  15 A and the second portion  15 B) therein. Nevertheless, in other embodiments, for example, a squeeze portion may be configured to pinch a developer bag. 
         [0068]    As illustrated in  FIG. 9A , in a fifth alternative embodiment, for example, a waste bag storage portion  70  includes a squeeze portion  71  at its entrance. The squeeze portion  71  may be made of sponge. The waste bag storage portion  70  is configured to pinch a connecting portion  51 D of the developer bag  51 . The squeeze portion  71  includes a first portion  71 A and a second portion  71 B, each of which is fixed to the housing  2 . The first portion  71 A and the second portion  71 B pinch the developer bag  51  therebetween. Therefore, in response to rolling up of the connecting portion  51 D by the winding shaft  11 , toner T remaining in the developer bag  51  is squeezed therefrom by elastic force of the sponges. According to the fifth alternative embodiment, this configuration may therefore minimize residual toner T in the developer bag  51 . 
       Sixth Alternative Embodiment 
       [0069]    In other embodiments, for example, a squeeze portion may pinch the connecting portion  51 D using an urging member. As illustrated in  FIG. 9B , in a six alternative embodiment, for example, a squeeze portion  81  is disposed at an entrance of a waste bag storage portion  80  and includes a first portion  81 A, a second portion  81 B, and an urging member  81 C. The first portion  81 A is supported by the housing  2  and is configured to move in a direction in which the first portion  81 A moves closer to and away from the second portion  81 B. The urging member  81 C urges the first portion  81 A toward the second portion  81 B. The second portion  81 B is fixedly supported by the housing  2 . According to the sixth alternative embodiment, the first portion  81 A is urged toward the second portion  81 B. Thus, the first portion  81 A and the second portion  81 B pinch the developer bag  51  therebetween. Therefore, this configuration may also enable remaining toner T to be squeezed out of the developer bag  51 , and minimize residual toner T on the interior surface of the developer bag  51  (also refer to  FIG. 7 ). 
       Seventh Alternative Embodiment 
       [0070]    In the illustrative embodiment, the squeeze portion  15  includes the first portion  15 A and the second portion  15 B that is spaced from the upper wall  2  of the housing  2 . Nevertheless, the configuration of the squeeze portion might not be limited to the specific example. As illustrated in  FIG. 9C , in a seventh alternative embodiment, for example, a squeeze portion  91  includes a protruding wall and the lower wall  13 A of the waste bag storage portion  13 . The protruding wall extends from the upper wall  2 A of the housing  2  toward the lower wall  13 A of the waste bag storage portion  13 . A distal end of the protruding wall of the squeeze portion  91  is spaced from the lower wall  13 A by a predetermined distance. The connecting portion  22  of the developer bag  20  is connected to the winding shaft  11  through between the protruding wall of the squeeze portion  91  and the lower wall  13 A. According to the seventh alternative embodiment, this configuration may also enable remaining toner T to be squeezed out of the developer bag  20 , and minimize residual toner T on the interior surface of the developer bag  20  (also refer to  FIG. 1 ). 
         [0071]    In the illustrative embodiment, the winding shaft  11  is driven by the motor. Nevertheless, in other embodiments, for example, the winding shaft may be rotated manually. 
         [0072]    In the illustrative embodiment, the developer bag  20  consists of a single sheet member. Nevertheless, in other embodiments, for example, a developer bag may consist of a plurality of sheet members, e.g., two or more sheet members.
A developing cartridge includes a developing roller, a developer bag, a housing, and a shaft. The developer bag stores a developer therein. The housing includes a developer storage chamber accommodating the developer bag therein. The housing supports the developing roller. The shaft is fixed to the developer bang and movable pull the developer bag theretoward.