Patent Publication Number: US-2023138422-A1

Title: Developer cartridge and image forming apparatus

Description:
REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority from Japanese Patent Application No. 2021-179840, which was filed on Nov. 2, 2021, the disclosure of which is herein incorporated by reference in its entirety. 
     BACKGROUND ART 
     The following disclosure relates to a developer cartridge and an image forming apparatus. 
     There has been known a conventional image forming apparatus including an apparatus body having an opening, a cartridge and an intermediate transfer unit located above the cartridge. The cartridge includes, as one body, a photoconductive drum and a developing unit. The developing unit includes a developing roller. The cartridge is mountable on and removable from the apparatus body in an axis direction of the photoconductive drum through the opening. 
     DESCRIPTION 
     In the image forming apparatus, there is a case in which the cartridge is configured such that the cartridge is dividable into a drum cartridge including the photoconductive drum and a developer cartridge including the developing roller. 
     In the conventional image forming apparatus, however, the opening through which the cartridge passes is located on a first side with respect to the cartridge in the axis direction of the photoconductive drum. Accordingly, it is hard to provide a member supporting a first end of the drum cartridge in the axis direction of the photoconductive drum and supporting a first end of the developer cartridge in the axis direction of the photoconductive drum. 
     Accordingly, it is hard to secure degree of parallelization of the developing roller with respect to the photoconductive drum while the developing roller is configured to be movable with respect to the photoconductive drum. 
     An aspect of the disclosure relates to a developer cartridge and an image forming apparatus capable of securing degree of parallelization of a developing roller with respect to a photoconductive drum while the developing roller is movable with respect to the photoconductive drum. 
     In one aspect of the disclosure, a developer cartridge includes a developing roller, a developer housing supporting the developing roller, and a toner storage unit including a first storage chamber capable of storing toner, and a second storage chamber storing the developer housing. The toner storage unit supports the developer housing such that the developer housing is movable with respect to the first storage chamber. 
     In another aspect of the disclosure, an image forming apparatus includes a body housing, a transfer unit, a drum cartridge including a photoconductive drum and located below the transfer unit in a state in which the drum cartridge is mounted on the body housing, a developer cartridge including a developing roller, a developer housing supporting the developing roller, and a toner storage unit including a first storage chamber capable of storing toner and a second storage chamber storing the developer housing, the toner storage unit supporting the developer housing such that the developer housing is movable with respect to the first storage chamber, a support frame supporting the toner storage unit in a state in which the developer cartridge is mounted on the body housing. 
    
    
     
       The objects, features, advantages, and technical and industrial significance of the present disclosure will be better understood by reading the following detailed description of the embodiments, when considered in connection with the accompanying drawings, in which: 
         FIG.  1    is a schematic view of a configuration of an image forming apparatus; 
         FIG.  2    is a view for explaining mounting and removing of a drum cartridge and a developer cartridge illustrated in  FIG.  1    in a state in which a cover is positioned at a closed position; 
         FIG.  3    is a state in which the cover illustrated in  FIG.  2    is positioned at an open position; 
         FIG.  4    is a cross-sectional view of a central part of the developer cartridge illustrated in  FIG.  1   ; 
         FIG.  5    is a disassembled perspective view of the developer cartridge illustrated in  FIG.  1   ; 
         FIG.  6    is a view for explaining a movement of the developer cartridge in a state in which a support frame is positioned at a frame first position and the developer cartridge is positioned at a first position; 
         FIG.  7    is a view for explaining of a movement of the developer cartridge in a state in which the support frame is positioned at a frame second position and the developer cartridge is positioned at a second position; 
         FIG.  8    is a disassembled perspective view of a developer cartridge; 
         FIG.  9    is a side view of the developer cartridge illustrated in  FIG.  8   ; 
         FIG.  10    is a disassembled perspective view of a developer cartridge; and 
         FIG.  11    is a side view of the developer cartridge illustrated in  FIG.  10   ; 
         FIG.  12    is a disassembled perspective view of a developer cartridge; and 
         FIG.  13    is a cross-sectional view of the developer cartridge illustrated in  FIG.  12    illustrating a cross section passing a developer rib and a toner rib. 
     
    
    
     OVERVIEW OF IMAGE FORMING APPARATUS 
     There will be described an overview of an image forming apparatus  1  in detail with reference to  FIG.  1    to  FIG.  3   . 
     It is noted that an up and down direction in the following description is an up and down direction defined when the image forming apparatus  1  is placed on a horizontal plane. Moreover, a first direction in the description of the image forming apparatus  1  is a first direction defined when a developer cartridge  6 Y is mounted on the image forming apparatus  1 . 
     As illustrated in  FIG.  1   , the image forming apparatus  1  includes a body housing  2 , a cover  3  (see  FIG.  2   ), a sheet tray  4 , a plurality of drum cartridges  5 Y,  5 M,  5 C,  5 K, a plurality of developer cartridges  6 Y,  6 M,  6 C,  6 K, an exposing unit  7 , a transfer unit  8 , a transfer roller  9  and a fixing unit  10 . 
     Body Housing 
     The body housing  2  accommodates the sheet tray  4 , the plurality of drum cartridges  5 Y,  5 M,  5 C,  5 K, the plurality of developer cartridges  6 Y,  6 M,  6 C,  6 K, the exposing unit  7 , the transfer unit  8 , the transfer roller  9  and the fixing unit  10 . The body housing  2  has an opening  21  (see  FIG.  3   ). The opening  21  is located at a first end of the body housing  2  in the first direction. 
     Cover 
     As illustrated in  FIG.  2    and  FIG.  3   , the cover  3  is movable between a closed position (see  FIG.  2   ) and an open position (see  FIG.  3   ). In a state in which the cover  3  is positioned at the closed position, the cover  3  closes the opening  21 . In a state in which the cover  3  is positioned at the open position, the opening  21  is open. 
     Sheet Tray 
     As illustrated in  FIG.  1   , the sheet tray  4  is capable of accommodating a sheet S. The sheet S in the sheet tray  4  is conveyed toward the transfer roller  9 . 
     Drum Cartridges 
     As illustrated in  FIG.  3   , in the state in which the cover  3  is positioned at the open position, each of the plurality of drum cartridges  5 Y,  5 M,  5 C,  5 K is mountable on and removable from the body housing  2  through the opening  21 . Each of the plurality of drum cartridges  5 Y,  5 M,  5 C,  5 K is mountable on and removable from the body housing  2  in the first direction. As illustrated in  FIG.  1   , in a state in which the plurality of drum cartridges  5 Y,  5 M,  5 C,  5 K are mounted on the body housing  2 , the plurality of drum cartridges  5 Y,  5 M,  5 C,  5 K are located below the transfer unit  8 . The drum cartridge  5 Y includes a photoconductive drum  51 Y and a charging unit  52 Y. 
     The photoconductive drum  51 Y extends in the first direction. The photoconductive drum  51 Y has a cylindrical shape. The photoconductive drum  51 Y is rotatable around a drum axis A 1 . The drum axis A 1  extends in the first direction. 
     The charging unit  52 Y charges the photoconductive drum  51 Y. In the present embodiment, the charging unit  52 Y is a charging roller. The charging unit  52 Y may be a scorotron type charging unit. 
     It is noted that each of the drum cartridges  5 M,  5 C,  5 K has the same configuration as the drum cartridge  5 Y. Accordingly, an explanation of the drum cartridges  5 M,  5 C,  5 K is dispensed with. 
     Developer Cartridges 
     As illustrated in  FIG.  3   , in the state in which the cover  3  is positioned at the open position, the plurality of developer cartridges  6 Y,  6 M,  6 C,  6 K are mountable on and removable from the body housing  2  through the opening  21 . As illustrated in  FIG.  1   , in a state in which the plurality of developer cartridges  6 Y,  6 M,  6 C,  6 K are mounted on the body housing  2 , the plurality of developer cartridges  6 Y,  6 M,  6 C,  6 K are located below the transfer unit  8 . The developer cartridge  6 Y includes a toner storage unit  61 Y and a developing unit  62 Y. 
     The toner storage unit  61 Y is capable of storing toner. 
     The developing unit  62 Y is supported by the toner storage unit  61 Y. The developing unit  62 Y includes a developer housing  621 Y and a developing roller  622 Y. In other words, the developer cartridge  6 Y includes the developer housing  621 Y and the developing roller  622 Y. 
     The developer housing  621 Y supports the developing roller  622 Y. The developer housing  621 Y is capable of receiving toner from the toner storage unit  61 Y. The developer housing  621 Y is capable of storing the toner from the toner storage unit  61 Y. 
     The developing roller  622 Y is capable of supplying the toner in the developer housing  621 Y to the photoconductive drum  51 Y. The developing roller  622 Y is in contact with the photoconductive drum  51 Y. The developing roller  622 Y may be capable of being spaced apart from the photoconductive drum  51 Y. The developing roller  622 Y extends in the first direction. The developing roller  622 Y is rotatable around a developer axis A 2 . The developer axis A 2  extends in the first direction. 
     It is noted that each of the developer cartridges  6 M,  6 C,  6 K has the same configuration as the developer cartridge  6 Y. Accordingly, an explanation of the developer cartridges  6 M,  6 C,  6 K is dispensed with. 
     Exposing Unit 
     In a state in which the plurality of drum cartridges  5 Y,  5 M,  5 C,  5 K are mounted on the image forming apparatus  1 , the exposing unit  7  is capable of exposing a circumferential surface of each of the photoconductive drums  51 Y,  51 M,  51 C,  51 K. In the present embodiment, the exposing unit  7  is a laser scanning unit. 
     Transfer Unit 
     In the state in which the plurality of drum cartridges  5 Y,  5 M,  5 C,  5 K are mounted on the image forming apparatus  1 , the transfer unit  8  is located above the plurality of drum cartridges  5 Y,  5 M,  5 C,  5 K. The transfer unit  8  includes an intermediate belt  81  and transfer rollers  82 Y,  82 M,  82 C,  82 K. 
     In the state in which the plurality of drum cartridges  5 Y,  5 M,  5 C,  5 K are mounted on the image forming apparatus  1 , the intermediate belt  81  is in contact with each of the photoconductive drums  51 Y,  51 M,  51 C,  51 K. 
     The transfer roller  82 Y transfers toner on the photoconductive drum  51 Y to the intermediate belt  81 . The transfer roller  82 M transfers toner on the photoconductive drum  51 M to the intermediate belt  81 . The transfer roller  82 C transfers toner on the photoconductive drum  51 C to the intermediate belt  81 . The transfer roller  82 K transfers toner on the photoconductive drum  51 K to the intermediate belt  81 . 
     Transfer Roller 
     The transfer roller  9  transfers the toner on the intermediate belt  81  to the sheet S. More specifically, the sheet S conveyed from the sheet tray  4  toward the transfer roller  9  is conveyed to the fixing unit  10  between the transfer roller  9  and the intermediate belt  81 . At this time, the transfer roller  9  transfers the toner on the intermediate belt  81  to the sheet S. 
     Fixing Unit 
     The fixing unit  10  heats and presses the sheet S to which the toner is transferred, and causes the toner to be fixed onto the sheet S. The sheet S having passed through the fixing unit  10  is discharged to an upper surface of the body housing  2 . 
     Details of Developer Cartridge 
     Next, there will be described the developer cartridge  6 Y in detail with reference to  FIG.  4    to  FIG.  7   . As illustrated in  FIG.  4    and  FIG.  5   , the developer cartridge  6 Y includes a first seal member  63 , a second seal member  64 , an agitator  65  (see  FIG.  4   ) in addition to the toner storage unit  61 Y and the developing unit  62 Y. 
     Details of Toner Storage Unit 
     As illustrated in  FIG.  5   , the toner storage unit  61 Y extends in the first direction. The toner storage unit  61 Y includes a first storage chamber  611  and a second storage chamber  612 . 
     First Storage Chamber 
     The first storage chamber  611  is capable of storing toner. The first storage chamber  611  extends in the first direction. The first storage chamber  611  has a cylindrical shape. As illustrated in  FIG.  4   , in a state in which the developer cartridge  6 Y is mounted on the image forming apparatus  1 , an upper surface T of the toner in the first storage chamber  611  indicating an amount of the toner in the first storage chamber  611  is located at a position lower than the developer housing  621 Y. In other words, in the state in which the developer cartridge  6 Y is mounted on the image forming apparatus  1 , the upper surface T of the toner in the toner storage unit  61 Y indicating the amount of the toner in the toner storage unit  61 Y is located at the position lower than the developer housing  621 Y. 
     As illustrated in  FIG.  5   , the first storage chamber  611  includes an opening  6111 , a first support surface  6112 A, a second support surface  6112 B (see  FIG.  4   ), a third support surface  6112 C, a fourth support surface  6112 D and a fifth support surface  6112 E (see  FIG.  4   ). In other words, the toner storage unit  61 Y includes the opening  6111 , the first support surface  6112 A, the second support surface  6112 B and the third support surface  6112 C. 
     The opening  6111  allows the first storage chamber  611  and the second storage chamber  612  to be communicated with each other. The opening  6111  is located at a boundary position between the first storage chamber  611  and the second storage chamber  612 . In the state in which the developer cartridge  6 Y is mounted on the image forming apparatus  1 , the opening  6111  is located at an upper end of the first storage chamber  611 . The opening  6111  extends in the first direction. The opening  6111  communicates with an inlet opening  6211  of the developer housing  621 Y (see  FIG.  4   ). The inlet opening  6211  will be described below. The toner is permitted to pass through the opening  6111  from the toner storage unit  61 Y to the developer housing  621 Y. 
     The first support surface  6112 A is located on a first side with respect to the opening  6111  in the first direction. The first support surface  6112 A supports a first end of the developer housing  621 Y in the first direction. The first support surface  6112 A has a width in the first direction and extends in a second direction. The second direction intersects the first direction. It is preferable that the second direction is orthogonal to the first direction. 
     The second support surface  6112 B illustrated in  FIG.  4    is located on a second side with respect to the opening  6111  in the first direction (see  FIG.  5   ). In other words, the second support surface  6112 B is located on an opposite side of the first support surface  6112 A with respect to the opening  6111  in the first direction. The second support surface  6112 B supports a second end of the developer housing  621 Y in the first direction. As similar to the first support surface  6112 A, the second support surface  6112 B has a width in the first direction and extends in the second direction. 
     The third support surface  6112 C is located on a first side with respect to the opening  6111  in the second direction. The third support surface  6112 C supports a first end of the developer housing  621 Y in the second direction. The third support surface  6112 C has a width in the second direction and extends in the first direction. A first end of the third support surface  6112 C in the first direction continues to the first support surface  6112 A. A second end of the third support surface  6112 C in the first direction continues to the second support surface  6112 B. 
     The fourth support surface  6112 D is located on the first side with respect to the opening  6111  in the first direction. The fourth support surface  6112 D supports the first end of the developer housing  621 Y in the first direction together with the first support surface  6112 A. The fourth support surface  6112 D has a width in the first direction and extends in a third direction. The third direction intersects the first direction and the second direction. It is preferable that the third direction is orthogonal to the first direction and intersects the second direction. In the state in which the developer cartridge  6 Y is mounted on the image forming apparatus  1 , the third direction is an up and down direction. A first end of the fourth support surface  6112 D in the third direction continues to the first support surface  6112 A. A second end of the fourth support surface  6112 D in the third direction continues to an inner surface of a cover side wall  6122 . 
     The fifth support surface  6112 E illustrated in  FIG.  4    is located on the second side with respect to the opening  6111  in the first direction. The fifth support surface  6112 E supports the second end of the developer housing  621 Y in the first direction together with the second support surface  6112 B. As similar to the fourth support surface  6112 D (see  FIG.  5   ), the fifth support surface  6112 E has a width in the first direction and extends in the third direction. A first end of the fifth support surface  6112 E in the third direction continues to the second support surface  6112 B. A second end of the fifth support surface  6112 E in the third direction continues to the inner surface of the cover side wall  6122 . 
     Second Storage Chamber 
     The second storage chamber  612  stores the developer housing  621 Y. The second storage chamber  612  is located on a second side with respect to the first storage chamber  611  in the third direction. In the state in which the developer cartridge  6 Y is mounted on the image forming apparatus  1 , the second storage chamber  612  is located above the first storage chamber  611 . 
     As illustrated in  FIG.  5   , the second storage chamber  612  includes two support side walls  6121 A,  6121 B, the cover side wall  6122  and two receiving portions  6123 A,  6123 B. In other words, the toner storage unit  61 Y includes the cover side wall  6122  and the two receiving portions  6123 A,  6123 B. 
     The support side wall  6121 A is located on a first end of the toner storage unit  61 Y in the first direction. The support side wall  6121 A is located on a first side with respect to the first support surface  6112 A in the first direction. In other words, the support side wall  6121 A is located on an outer side with respect to the first support surface  6112 A in the first direction. The support side wall  6121 A is located on an opposite side of the opening  6111  in the first direction with respect to the first support surface  6112 A. The support side wall  6121 A extends in the second direction and the third direction. The support side wall  6121 A supports the first end of the developer housing  621 Y in the first direction. The support side wall  6121 A has a hole  61211 A and a hole  61212 A. In other words, the second storage chamber  612  of the toner storage unit  61 Y has the hole  61212 A. 
     The hole  61211 A is located at a first end of the support side wall  6121 A in the second direction. The hole  61212 A is located on an opposite side of the cover side wall  6122  in the second direction with respect to the opening  6111 . The hole  61211 A has a circular shape. A shaft  623 A of the developing unit  62 Y is fitted into the hole  61211 A. The shaft  623 A will be described below. 
     The hole  61212 A is spaced apart from the hole  61211 A. In the present embodiment, the hole  61212 A is located between the hole  61211 A and the cover side wall  6122  in the second direction. The hole  61212 A extends in a direction intersecting the first direction. More specifically, the hole  61212 A extends in a circumferential direction of a circle centered around the hole  61211 A. A protrusion  624 A of the developing unit  62 Y is fitted into the hole  61212 A. The protrusion  624 A will be described below. 
     The support side wall  6121 B is located at a second end of the toner storage unit  61 Y in the first direction. The support side wall  6121 B is located on a second side with respect to the second support surface  6112 B (see  FIG.  4   ) in the first direction. In other words, the support side wall  6121 B is located on an outer side with respect to the second support surface  6112 B in the first direction. The support side wall  6121 B is located on an opposite side of the opening  6111  in the first direction with respect to the second support surface  6112 B. The support side wall  6121 B extends in the second direction and the third direction. The support side wall  6121 B supports the second end of the developer housing  621 Y in the first direction. The support side wall  6121 B has a hole  61211 B and a hole  61212 B. 
     The hole  61211 B is located at a first end of the support side wall  6121 B in the second direction. The hole  61212 B is located on an opposite side of the cover side wall  6122  in the second direction with respect to the opening  6111 . The hole  61211 B has a circular shape. A shaft  623 B of the developing unit  62 Y is fitted into the hole  61211 B. The shaft  623 B will be described below. 
     The hole  61212 B is spaced apart from the hole  61211 B. In the present embodiment, the hole  61212 B is located between the hole  61211 B and the cover side wall  6122  in the second direction. The hole  61212 B extends in a direction in which the hole  61212 A extends. That is, the hole  61212 B extends in a circumferential direction of a circle centered around the hole  61211 B. A protrusion  624 B of the developing unit  62 Y is fitted into the hole  61212 B. The protrusion  624 B will be described below. 
     The cover side wall  6122  is located on the second side with respect to the opening  6111  in the second direction. The cover side wall  6122  covers the second end of the developer housing  621 Y in the second direction. The cover side wall  6122  extends in the first direction. The cover side wall  6122  is inclined with respect to the third direction. As illustrated in  FIG.  4   , the cover side wall  6122  is inclined so as to be apart from the developer housing  621 Y in the second direction as approaching the first storage chamber  611  in the third direction. As illustrated in  FIG.  5   , a first end of the cover side wall  6122  in the first direction is connected to the support side wall  6121 A. A second end of the cover side wall  6122  in the first direction is connected to the support side wall  6121 B. 
     The receiving portion  6123 A is located on an outer side with respect to the support side wall  6121 A in the first direction. In other words, the receiving portion  6123 A is located on an opposite side of the opening  6111  in the first direction with respect to the support side wall  6121 A. In the present embodiment, the receiving portion  6123 A protrudes outwardly, in the first direction, from an outer surface of the support side wall  6121 A in the first direction. In other words, the receiving portion  6123 A protrudes outwardly, in the first direction, from an outer surface of the second storage chamber  612  in the first direction. It is noted that the receiving portion  6123 A may be attached to the outer surface of the support side wall  6121 A. The receiving portion  6123 A has a tubular shape. In the present embodiment, the receiving portion  6123 A has a cylindrical shape. An inner space of the receiving portion  6123 A communicates with the hole  61211 A. The shaft  623 A is fitted into the receiving portion  6123 A. The receiving portion  6123 A receives the shaft  623 A. 
     The receiving portion  6123 B is located on an outer side with respect to the support side wall  6121 B in the first direction. In other words, the receiving portion  6123 B is located on an opposite side of the opening  6111  in the first direction with respect to the support side wall  6121 B. In the present embodiment, the receiving portion  6123 B protrudes outwardly, in the first direction, from an outer surface of the support side wall  6121 B in the first direction. In other words, the receiving portion  6123 B protrudes outwardly, in the first direction, from the outer surface of the second storage chamber  612  in the first direction. It is noted that the receiving portion  6123 B may be attached to the outer surface of the support side wall  6121 B. The receiving portion  6123 B has a tubular shape. In the present embodiment, the receiving portion  6123 B has a cylindrical shape. An inner space of the receiving portion  6123 B communicates with the hole  61211 B. The shaft  623 B is fitted into the receiving portion  6123 B. The receiving portion  6123 B receives the shaft  623 B. 
     Details of Developing Unit 
     The developing unit  62 Y includes the two shafts  623 A,  623 B and the two protrusions  624 A,  624 B in addition to the developer housing  621 Y and the developing roller  622 Y. In other words, the developer cartridge  6 Y includes the two shafts  623 A,  623 B. In the present embodiment, the shaft  623 A functions as a first engaging portion, and the shaft  623 B functions as a second engaging portion. 
     Details of Developer Housing 
     The developer housing  621 Y extends in the first direction. The developer housing  621 Y has a tubular shape. As illustrated in  FIG.  4   , the second end of the developer housing  621 Y in the second direction is opposed to the cover side wall  6122 . The developer housing  621 Y has the inlet opening  6211 . 
     The inlet opening  6211  is capable of receiving toner from the toner storage unit  61 Y. The toner from the toner storage unit  61 Y enters into the developer housing  621 Y passing between the cover side wall  6122  and the developer housing  621 Y, and through the inlet opening  6211 . The inlet opening  6211  is located at the second end of the developer housing  621 Y in the second direction. 
     Shaft 
     As illustrated in  FIG.  5   , the shaft  623 A is located at the first end of the developer housing  621 Y in the first direction. The shaft  623 A protrudes outwardly, in the first direction, from a first side surface of the developer housing  621 Y in the first direction. It is noted that the shaft  623 A may be attached to the first side surface of the developer housing  621 Y in the first direction. The shaft  623 A is spaced apart from the developer axis A 2 . The shaft  623 A has a column shape. The shaft  623 A is fitted into the receiving portion  6123 A of the toner storage unit  61 Y through the hole  61211 A of the toner storage unit  61 Y. 
     The shaft  623 B is located at the second end of the developer housing  621 Y in the first direction. The shaft  623 B protrudes outwardly, in the first direction, from a second side surface of the developer housing  621 Y in the first direction. It is noted that the shaft  623 B may be attached to the second side surface of the developer housing  621 Y in the first direction. The shaft  623 B is spaced apart from the developer axis A 2 . The shaft  623 B has a column shape. The shaft  623 B is fitted into the receiving portion  6123 B of the toner storage unit  61 Y through the hole  61211 B of the toner storage unit  61 Y. 
     Protrusion 
     The protrusion  624 A protrudes outwardly, in the first direction, from the first side surface of the developer housing  621 Y in the first direction. It is noted that the protrusion  624 A may be attached to the first side surface of the developer housing  621 Y in the first direction. The protrusion  624 A is spaced apart from the shaft  623 A. The protrusion  624 A has a cylindrical shape. In the present embodiment, the protrusion  624 A receives a shaft of the developing roller  622 Y. The protrusion  624 A is fitted into the hole  61212 A of the toner storage unit  61 Y. 
     The protrusion  624 B protrudes outwardly, in the first direction, from the second side surface of the developer housing  621 Y in the first direction. It is noted that the protrusion  624 B may be attached to the second side surface of the developer housing  621 Y of the first direction. The protrusion  624 B is spaced apart from the shaft  623 B. The protrusion  624 B has a cylindrical shape. In the present embodiment, the protrusion  624 B receives the shaft of the developing roller  622 Y. The protrusion  624 B is fitted into the hole  61212 B of the toner storage unit  61 Y. 
     When the shaft  623 A is fitted into the receiving portion  6123 A, the shaft  623 B is fitted into the receiving portion  6123 B, the protrusion  624 A is fitted into the hole  61212 A and the protrusion  624 B is fitted into the hole  61212 B, the developer housing  621 Y is supported by the toner storage unit  61 Y so as to be movable. The developer housing  621 Y is movable with respect to the toner storage unit  61 Y in a direction in which each of the hole  61212 A and the hole  61212 B extends. In the present embodiment, the developer housing  621 Y is rotatable around the shaft  623 A and the shaft  623 B with respect to the toner storage unit  61 Y. 
     First Seal Member 
     As illustrated in  FIG.  4   , the first seal member  63  seals an area between the toner storage unit  61 Y and the developer housing  621 Y. The first seal member  63  is elastically deformable in accordance with a movement of the developer housing  621 Y. The first seal member  63  is, for example, a sponge. As illustrated in  FIG.  5   , the first seal member  63  includes a first seal portion  63 A, a second seal portion  63 B, a third seal portion  63 C, a fourth seal portion  63 D and a fifth seal portion  63 E. 
     The first seal portion  63 A is located at a first end of the first seal member  63  in the first direction. The first seal portion  63 A has a width in the first direction and extends in the second direction. The first seal portion  63 A is located between the first end of the developer housing  621 Y in the first direction and the first support surface  6112 A of the toner storage unit  61 Y. The first seal portion  63 A is in contact with the first end of the developer housing  621 Y in the first direction and the first support surface  6112 A of the toner storage unit  61 Y. The first seal portion  63 A seals an area between the first end of the developer housing  621 Y and the first support surface  6112 A in the first direction. 
     The second seal portion  63 B is located at a second end of the first seal member  63  in the first direction. The second seal portion  63 B is spaced apart from the first seal portion  63 A in the first direction. The second seal portion  63 B has a width in the first direction and extends in the second direction. The second seal portion  63 B is located between the second end of the developer housing  621 Y in the first direction and the second support surface  6112 B of the toner storage unit  61 Y (see  FIG.  4   ). The second seal portion  63 B is in contact with the second end of the developer housing  621 Y in the first direction and the second support surface  6112 B of the toner storage unit  61 Y. The second seal portion  63 B seals an area between the second end of the developer housing  621 Y in the first direction and the second support surface  6112 B. 
     The third seal portion  63 C is located between the first seal portion  63 A and the second seal portion  63 B in the first direction. The third seal portion  63 C has a width in the second direction and extends in the first direction. A first end of the third seal portion  63 C in the first direction continues to the first seal portion  63 A. A second end of the third seal portion  63 C in the first direction continues to the second seal portion  63 B. The third seal portion  63 C is located between the first end of the developer housing  621 Y in the second direction and the third support surface  6112 C of the toner storage unit  61 Y. The third seal portion  63 C is in contact with the first end of the developer housing  621 Y in the second direction and the third support surface  6112 C of the toner storage unit  61 Y. The third seal portion  63 C seals an area between the first end of the developer housing  621 Y in the second direction and the third support surface  6112 C. 
     The fourth seal portion  63 D is located at the first end of the first seal member  63  in the first direction. The fourth seal portion  63 D is located at a second end of the first seal portion  63 A in the second direction. The fourth seal portion  63 D has a width in the first direction. The fourth seal portion  63 D extends, in the third direction, from the second end of the first seal portion  63 A in the second direction. The fourth seal portion  63 D is located between the first end of the developer housing  621 Y the first direction and the fourth support surface  6112 D of the toner storage unit  61 Y. The fourth seal portion  63 D is in contact with the first end of the developer housing  621 Y in the first direction and the fourth support surface  6112 D of the toner storage unit  61 Y. The fourth seal portion  63 D seals an area between the first end of the developer housing  621 Y in the first direction and the fourth support surface  6112 D. 
     The fifth seal portion  63 E is located at the second end of the first seal member  63  in the first direction. The fifth seal portion  63 E is located at a second end of the second seal portion  63 B in the second direction. The fifth seal portion  63 E has a width in the first direction. The fifth seal portion  63 E extends, in the third direction, from the second end of the second seal portion  63 B in the first direction. The fifth seal portion  63 E is located between the second end of the developer housing  621 Y in the first direction and the fifth support surface  6112 E of the toner storage unit  61 Y (see  FIG.  4   ). The fifth seal portion  63 E is in contact with the second end of the developer housing  621 Y in the first direction and the fifth support surface  6112 E of the toner storage unit  61 Y. The fifth seal portion  63 E seals an area between the second end of the developer housing  621 Y in the first direction and the fifth support surface  6112 E. 
     Second Seal Member 
     As illustrated in  FIG.  4   , the second seal member  64  is located between the second end of the developer housing  621 Y in the second direction and the cover side wall  6122  of the toner storage unit  61 Y. As illustrated in  FIG.  5   , the second seal member  64  extends in the first direction. The second seal member  64  extends in the first direction from the fourth seal portion  63 D to the fifth seal portion  63 E. The second seal member  64  is adhered to the second end of the developer housing  621 Y in the second direction and in contact with the cover side wall  6122  of the toner storage unit  61 Y. The second seal member  64  seals an area between the second end of the developer housing  621 Y in the second direction and the cover side wall  6122 . The second seal member  64  is, for example, a film. The second seal member  64  may be a sponge. 
     Agitator 
     As illustrated in  FIG.  4   , the agitator  65  is located in the first storage chamber  611  of the toner storage unit  61 Y. The agitator  65  is capable of agitating the toner in the first storage chamber  611  of the toner storage unit  61 Y. The agitator  65  is capable of conveying the toner in the toner storage unit  61 Y toward the inlet opening  6211  of the developer housing  621 Y. The agitator  65  is rotatable around an agitator axis A 3 . The agitator axis A 3  extends in the first direction. In the state in which the developer cartridge  6 Y is mounted on the image forming apparatus  1 , the agitator axis A 3  is located at a position lower than the developer housing  621 Y. The agitator  65  includes a shaft  651  and a blade  652 . 
     The shaft  651  extends in the first direction along the agitator axis A 3 . 
     The blade  652  extends from the shaft  651 . The blade  652  is rotatable together with the shaft  651 . The blade  652  is capable of conveying the toner in the toner storage unit  61 Y toward the inlet opening  6211 . An edge of the blade  652  is reachable to the inlet opening  6211 . 
     Details of Drum Cartridge 
     There will be described the drum cartridge  5 Y in detail with reference to  FIG.  2   ,  FIG.  3    and  FIG.  6   . 
     As illustrated in  FIG.  2   , the drum cartridge  5 Y includes two side plates  53 A,  53 B in addition to the photoconductive drum  51 Y and the charging unit  52 Y. 
     The side plate  53 A is located at a first end of the drum cartridge  5 Y in the first direction. The side plate  53 A supports a first end of the photoconductive drum  51 Y in the first direction. As illustrated in  FIG.  6   , the side plate  53 A includes a first engaged portion  531 A. In other words, the drum cartridge  5 Y includes the first engaged portion  531 A. 
     The first engaged portion  531 A is located at the first end of the drum cartridge  5 Y in the first direction. The first engaged portion  531 A is a groove. In a state in which the developer cartridge  6 Y and the drum cartridge  5 Y are mounted on the image forming apparatus  1 , the receiving portion  6123 A of the toner storage unit  61 Y is fitted into the first engaged portion  531 A. As a result of this, in the state in which the developer cartridge  6 Y and the drum cartridge  5 Y are mounted on the image forming apparatus  1 , the shaft  623 A of the developing unit  62 Y (see  FIG.  5   ) engages with the first engaged portion  531 A via the receiving portion  6123 A. 
     As illustrated in  FIG.  2   , the side plate  53 B is spaced apart from the side plate  53 A in the first direction. The side plate  53 B is located at a second end of the drum cartridge  5 Y in the first direction. The side plate  53 B supports a second end of the photoconductive drum  51 Y in the first direction. As illustrated in  FIG.  3   , the side plate  53 B includes a second engaged portion  531 B. In other words, the drum cartridge  5 Y includes the second engaged portion  531 B. 
     The second engaged portion  531 B is located at the second end of the drum cartridge  5 Y in the first direction. The second engaged portion  531 B is a groove. In the state in which the developer cartridge  6 Y and the drum cartridge  5 Y are mounted on the image forming apparatus  1 , the receiving portion  6123 B of the toner storage unit  61 Y is fitted into the second engaged portion  531 B. As a result of this, in the state in which the developer cartridge  6 Y and the drum cartridge  5 Y are mounted on the image forming apparatus  1 , the shaft  623 B of the developing unit  62 Y (see  FIG.  5   ) engages with the second engaged portion  531 B via the receiving portion  6123 B. 
     Details of Image Forming Apparatus 
     There will be described next the image forming apparatus  1  in detail with reference to  FIG.  6    and  FIG.  7   . 
     As illustrated in  FIG.  1   , the image forming apparatus  1  further includes a plurality of support frames  11 Y,  11 M,  11 C,  11 K. 
     The support frame  11 Y is located in the body housing  2 . In the state in which the developer cartridge  6 Y is mounted on the image forming apparatus  1 , the support frame  11 Y supports the toner storage unit  61 Y. 
     As illustrated in  FIG.  6    and  FIG.  7   , in a state in which the support frame  11 Y supports the toner storage unit  61 Y, the support frame  11 Y is movable between a frame first position (see  FIG.  6   ) and a frame second position (see  FIG.  7    ). In the present embodiment, the support frame  11 Y is pivotable around an axis A 4  between the frame first position and the frame second position. 
     As illustrated in  FIG.  6   , in a state in which the support frame  11 Y is positioned at the frame first position, the support frame  11 Y positions the developer cartridge  6 Y at a first position. In a state in which the developer cartridge  6 Y is positioned at the first position, the developing roller  622 Y (see  FIG.  1   ) is in contact with the photoconductive drum  51 Y (see  FIG.  1   ). 
     As illustrated in  FIG.  7   , in a state in which the support frame  11 Y is positioned at the frame second position, the support frame  11 Y positions the developer cartridge  6 Y at a second position. In a state in which the developer cartridge  6 Y is positioned at the second position, the developing roller  622 Y is spaced apart from the photoconductive drum  51 Y. 
     That is, in the state in which the drum cartridge  5 Y and the developer cartridge  6 Y are mounted on the image forming apparatus  1 , the developer cartridge  6 Y is movable between the first position and the second position. 
     As illustrated in  FIG.  6   , the support frame  11 Y includes a supporting portion  111 , an axis portion  112  and an arm portion  113 . 
     In the state in which the developer cartridge  6 Y is mounted on the image forming apparatus  1 , the supporting portion  111  supports the toner storage unit  61 Y. The supporting portion  111  extends in the first direction. The supporting portion  111  has an arc shape curved along an outer surface of the toner storage unit  61 Y. 
     The axis portion  112  is spaced apart from the supporting portion  111 . The axis portion  112  extends in the first direction along the axis A 4 . 
     The arm portion  113  connects the supporting portion  111  with the axis portion  112 . 
     Effects 
     According to the developer cartridge  6 Y, as illustrated in  FIG.  4    and  FIG.  5   , the toner storage unit  61 Y includes the first storage chamber  611  capable of storing toner and the second storage chamber  612  storing the developer housing  621 Y. And, the developer housing  621 Y is supported by the toner storage unit  61 Y so as to be movable. Accordingly, the developing roller  622 Y is movable with respect to the toner storage unit  61 Y. 
     And, as illustrated in  FIG.  1   , in a case where the developer cartridge  6 Y is mounted on the image forming apparatus  1  and the toner storage unit  61 Y of the developer cartridge  6 Y is supported by the image forming apparatus  1 , the developing roller  622 Y movable with respect to the toner storage unit  61 Y is in contact with the photoconductive drum  51 Y. Accordingly, the developing roller  622 Y becomes movable with respect to the photoconductive drum  51 Y. 
     Moreover, since the toner storage unit  61 Y can support the developer housing  621 Y, it is possible to secure degree of parallelization of the developing roller  622 Y with respect to the photoconductive drum  51 Y. 
     Accordingly, it is possible to secure the degree of parallelization of the developing roller  622 Y with respect to the photoconductive drum  51 Y while the developing roller  622 Y is movable with respect to the photoconductive drum  51 Y. 
     As illustrated in  FIG.  6   , the image forming apparatus  1  includes the support frame  11 Y. In the state in which the developer cartridge  6 Y is mounted on the image forming apparatus  1 , the support frame  11 Y supports the toner storage unit  61 Y of the developer cartridge  6 Y. 
     Accordingly, it is possible to bring the developing roller  622 Y into contact with the photoconductive drum  51 Y in a state in which the developing roller  622 Y is movable with respect to the toner storage unit  61 Y. Moreover, since the developer housing  621 Y is supported by the toner storage unit  61 Y, it is possible to secure the degree of parallelization of the developing roller  622 Y with respect to the photoconductive drum  51 Y. 
     Accordingly, it is possible to secure the degree of parallelization of the developing roller  622 Y with respect to the photoconductive drum  51 Y while the developing roller  622 Y is movable with respect to the photoconductive drum  51 Y. 
     According to the image forming apparatus  1 , as illustrated in  FIG.  6   , in a state in which the drum cartridge  5 Y and the developer cartridge  6 Y are mounted on the body housing  2 , the shaft  623 A of the developing unit  62 Y engages with the first engaged portion  531 A of the drum cartridge  5 Y via the receiving portion  6123 A. Moreover, in the state in which the drum cartridge  5 Y and the developer cartridge  6 Y are mounted on the body housing  2 , the shaft  623 B of the developing unit  62 Y (see  FIG.  5   ) engages with the second engaged portion  531 B of the drum cartridge  5 Y (see  FIG.  3   ) via the receiving portion  6123 B (see  FIG.  5   ). 
     As a result of this, in the state in which the drum cartridge  5 Y and the developer cartridge  6 Y are mounted on the body housing  2 , it is possible to support ends of the developer housing  621 Y in the first direction by the drum cartridge  5 Y. 
     Accordingly, it is possible to secure the degree of the parallelization of the developing roller  622 Y with respect to the photoconductive drum  51 Y more. 
     While the disclosure has been described in conjunction with various example structures outlined above and illustrated in the figures, various alternatives, modifications, variations, improvements, and/or substantial equivalents, whether known or that may be presently unforeseen, may become apparent to those having at least ordinary skill in the art. Accordingly, the example embodiments of the disclosure, as set forth above, are intended to be illustrative of the disclosure, and not limiting the disclosure. Various changes may be made without departing from the spirit and scope of the disclosure. Therefore, the disclosure is intended to embrace all known or later developed alternatives, modifications, variations, improvements, and/or substantial equivalents. Some specific examples of potential alternatives, modifications, or variations in the described disclosure are provided below. 
     Modifications 
     There will be described modifications of the developer cartridge  6 Y with reference to  FIG.  8    to  FIG.  13   . It is noted that the same reference numerals as used in the above-described embodiment are used to designate the corresponding elements of the modifications, and an explanation of which is dispensed with or simplified. 
     As illustrated in  FIG.  8   , the toner storage unit  61 Y may include a shaft  100 . In this case, the toner storage unit  61 Y does not include the receiving portions  6123 A,  6123 B. 
     The shaft  100  extends in the first direction. A first end of the shaft  100  in the first direction is supported by the support side wall  6121 A of the second storage chamber  612 . A second end of the shaft  100  in the first direction is supported by the support side wall  6121 B of the second storage chamber  612 . 
     The developer housing  621 Y has a hole  101 . It is noted that the developer housing  621 Y does not include the shafts  623 A,  623 B. 
     As illustrated in  FIG.  9   , the shaft  100  is fitted into the hole  101 . As a result of this, the shaft  100  supports the developer housing  621 Y. 
     Moreover, the support side wall  6121 A may have a cutout  102 A, and the support side wall  6121 B may have a cutout  102 B. The protrusion  624 A of the developing unit  62 Y is located in the cutout  102 A. The protrusion  624 B of the developing unit  62 Y is located in the cutout  102 B. 
     In the present modification, it is possible to achieve the same effects as achieved in the above-described embodiment. 
     The movement of the developer housing  621 Y with respect to the toner storage unit  61 Y is not limited to the rotation of the developer housing  621 Y with respect to the toner storage unit  61 Y. The developer housing  621 Y may be movable in a straight line with respect to the toner storage unit  61 Y. 
     In this case, as illustrated in  FIG.  10   , the support side wall  6121 A has a hole  201 A and a hole  202 A. 
     The hole  201 A is spaced apart from the cover side wall  6122  in the second direction. The hole  201 A extends in a direction intersecting the first direction. More specifically, in a state in which the drum cartridge  5 Y and the developer cartridge  6 Y are mounted on the image forming apparatus  1  and the developing roller  622 Y is in contact with the photoconductive drum  51 Y, the hole  201 A extends in a direction directed from the drum axis A 1  (see  FIG.  1   ) toward the developer axis A 2  (see  FIG.  1   ). The protrusion  624 A of the developing unit  62 Y is fitted into the hole  201 A. 
     The hole  202 A is spaced apart from the hole  201 A. The hole  202 A is located between the hole  201 A and the cover side wall  6122  in the second direction. The hole  202 A extends in a direction in which the hole  201 A extends. A protrusion  200 A of the developing unit  62 Y is fitted into the hole  202 A. It is noted that the protrusion  200 A is not illustrated. The protrusion  200 A will be described below. 
     The support side wall  6121 B has a hole  201 B and a hole  202 B. 
     The hole  201 B is spaced apart from the cover side wall  6122  in the second direction. The hole  201 B extends in a direction in which the hole  201 A extends. The protrusion  624 B of the developing unit  62 Y is fitted into the hole  201 B. 
     The hole  202 B is spaced apart from the hole  201 B. The hole  202 B is located between the hole  201 B and the cover side wall  6122  in the second direction. The hole  202 B extends in a direction in which the hole  201 A extends. A protrusion  200 B of the developing unit  62 Y is fitted into the hole  202 B. The protrusion  200 B will be described below. 
     The developing unit  62 Y includes the two protrusions  200 A,  200 B. The developing unit  62 Y does not include the shafts  623 A,  623 B. 
     The protrusion  200 A is spaced apart from the protrusion  624 A in the second direction. The protrusion  200 A protrudes outwardly, in the first direction, from the first side surface of the developer housing  621 Y in the first direction. It is noted that the protrusion  200 A may be attached to the first side surface of the developer housing  621 Y in the first direction. The protrusion  200 A is fitted to the hole  202 A of the toner storage unit  61 Y. 
     The protrusion  200 B is spaced apart from the protrusion  624 B in the second direction. The protrusion  200 B protrudes outwardly, in the first direction, from the second side surface of the developer housing  621 Y in the first direction. It is noted that the protrusion  200 B may be attached to the second side surface of the developer housing  621 Y in the first direction. The protrusion  200 B is fitted into the hole  202 B of the toner storage unit  61 Y. 
     As illustrated in  FIG.  11   , when the protrusion  624 A is fitted into the hole  201 A, the protrusion  624 B is fitted into the hole  201 B, the protrusion  200 A is fitted into the hole  202 A and the protrusion  200 B is fitted into the hole  202 B, the developer housing  621 Y is supported by the toner storage unit  61 Y so as to be movable. The developer housing  621 Y is movable with respect to the toner storage unit  61 Y in a direction in which each of the holes  201 A,  201 B,  202 A,  202 B extends. 
     Moreover, as illustrated in  FIG.  10   , the developer cartridge  6 Y may not include the second seal member  64  (see  FIG.  5   ). The developer cartridge  6 Y may include a seal member  203 . 
     The seal member  203  seals an area between the toner storage unit  61 Y and the developer housing  621 Y. The seal member  203  is elastically deformable in accordance with the movement of the developer housing  621 Y. The seal member  203  is, for example, a sponge. The seal member  203  includes a first seal portion  203 A, a second seal portion  203 B, a third seal portion  203 C, a fourth seal portion  203 D, a fifth seal portion  203 E and a sixth seal portion  203 F. 
     The first seal portion  203 A is located at a first end of the seal member  203  in the first direction. The first seal portion  203 A has a width in the first direction and extends in the second direction. The first seal portion  203 A is located between the first end of the developer housing  621 Y in the first direction and the first support surface  6112 A of the toner storage unit  61 Y. The first seal portion  203 A is in contact with the first end of the developer housing  621 Y in the first direction and the first support surface  6112 A of the toner storage unit  61 Y. The first seal portion  203 A seals an area between the first end of the developer housing  621 Y in the first direction and the first support surface  6112 A. 
     The second seal portion  63 B is located at a second end of the seal member  203  in the first direction. The second seal portion  203 B is spaced apart from the first seal portion  203 A in the first direction. The second seal portion  203 B has a width in the first direction and extends in the second direction. The second seal portion  203 B is located between the second end of the developer housing  621 Y in the first direction and the second support surface  6112 B of the toner storage unit  61 Y (see  FIG.  4   ). The second seal portion  203 B is in contact with the second end of the developer housing  621 Y in the first direction and the second support surface  6112 B of the toner storage unit  61 Y. The second seal portion  203 B seals an area between the second end of the developer housing  621 Y in the first direction and the second support surface  6112 B. 
     The third seal portion  203 C is located between the first seal portion  203 A and the second seal portion  203 B in the first direction. The third seal portion  203 C has a width in the second direction and extends in the first direction. A first end of the third seal portion  203 C in the first direction continues to the first seal portion  203 A. A second end of the third seal portion  203 C in the first direction continues to the second seal portion  203 B. The third seal portion  203 C is located between the first end of the developer housing  621 Y in the second direction and the third support surface  6112 C of the toner storage unit  61 Y. The third seal portion  203 C is in contact with the first end of the developer housing  621 Y in the second direction and the third support surface  6112 C of the toner storage unit  61 Y. The third seal portion  203 C seals an area between the first end of the developer housing  621 Y the second direction and the third support surface  6112 C. 
     The fourth seal portion  203 D is located between the second end of the developer housing  621 Y in the second direction and the cover side wall  6122  of the toner storage unit  61 Y. The fourth seal portion  203 D extends in the first direction. The fourth seal portion  203 D is in contact with the second end of the developer housing  621 Y in the second direction and the cover side wall  6122  of the toner storage unit  61 Y. The fourth seal portion  203 D seals an area between the second end of the developer housing  621 Y in the second direction and the cover side wall  6122 . 
     The fifth seal portion  203 E is located at the first end of the seal member  203  in the first direction. The fifth seal portion  203 E is located at a second end of the first seal portion  203 A in the second direction. The fifth seal portion  203 E has a width in the first direction. The fifth seal portion  203 E extends in the third direction. A first end of the fifth seal portion  203 E in the third direction continues to the first seal portion  203 A. A second end of the fifth seal portion  203 E in the third direction continues to the fourth seal portion  203 D. The fifth seal portion  203 E is located between the first end of the developer housing  621 Y in the first direction and the fourth support surface  6112 D of the toner storage unit  61 Y. The fifth seal portion  203 E is in contact with the first end of the developer housing  621 Y in the first direction and the fourth support surface  6112 D of the toner storage unit  61 Y. The fifth seal portion  203 E seals an area between the first end of the developer housing  621 Y in the first direction and the fourth support surface  6112 D. 
     The sixth seal portion  203 F is located at the second end of the seal member  203  in the first direction. The sixth seal portion  203 F is located at the second end of the second seal portion  203 B in the second direction. The sixth seal portion  203 F has a width in the first direction. The sixth seal portion  203 F extends in the third direction. A first end of the sixth seal portion  203 F in the third direction continues to the second seal portion  203 B. A second end of the sixth seal portion  203 F in the third direction continues to the fourth seal portion  203 D. The sixth seal portion  203 F is located between the second end of the developer housing  621 Y in the first direction and the fifth support surface  6112 E of the toner storage unit  61 Y (see  FIG.  4   ). The sixth seal portion  203 F is in contact with the second end of the developer housing  621 Y in the first direction and the fifth support surface  6112 E of the toner storage unit  61 Y. The sixth seal portion  203 F seals an area between the second end of the developer housing  621 Y in the first direction and the fifth support surface  6112 E. 
     In the present modification, it is possible to achieve the same effects as achieved in the above-described embodiment. In a case where the developing unit  62 Y is movable with respect to the toner storage unit  61 Y, the configuration supporting the developing unit  62 Y by the toner storage unit  61 Y is not limited to the above described configuration. 
     For example, as illustrated in  FIG.  12   , the developing unit  62 Y may include developer ribs  300 A,  300 B. In other words, the developer cartridge  6 Y may include the developer ribs  300 A,  300 B. It is noted that the developer rib  300 A is not illustrated. 
     The developer rib  300 A protrudes outwardly, in the first direction, from the first side surface of the developer housing  621 Y in the first direction. The developer rib  300 A has the same shape as the developer rib  300 B. 
     The developer rib  300 B protrudes outwardly, in the first direction, from the second side surface of the developer housing  621 Y in the first direction. The developer rib  300 B has a L-shape. 
     The toner storage unit  61 Y includes toner ribs  301 A,  301 B. 
     The toner rib  301 A protrudes inwardly, in the first direction, from an inner surface of the support side wall  6121 A in the first direction. The toner rib  301 A protrudes toward the developer rib  300 A from the inner surface of the support side wall  6121 A in the first direction. In other words, the toner rib  301 A protrudes toward the developer rib  300 A from an inner surface of the second storage chamber  612  in the first direction. The toner rib  301 A has a L-shape. The toner rib  301 A engages with the developer rib  300 A. 
     The toner rib  301 B protrudes inwardly, in the first direction, from an inner surface of the support side wall  6121 B in the first direction. The toner rib  301 B protrudes toward the developer rib  300 B from the inner surface of the support side wall  6121 B in the first direction. In other words, the toner rib  301 B protrudes toward the developer rib  300 B from the inner surface of the second storage chamber  612  in the first direction. The toner rib  301 B has a L-shape. As illustrated in  FIG.  13   , the toner rib  301 B engages with the developer rib  300 B. More specifically, the developer rib  300 B is located between the toner rib  301 B and the seal member  203 . 
     In the present modification, it is possible to achieve the same effects as achieved in the above-described embodiment.