Abstract:
A developing cartridge, comprising: a housing; a developing roller; a drive mechanism configured to transmit a driving force to the developing roller; and a restriction part configured to restrict movement of the housing when the restriction part engages with an external member, wherein the housing comprises: a first side wall; and a second side wall spaced from the first side wall in a first direction, wherein the drive mechanism is disposed to the second side wall, wherein: the restriction part is disposed to the first side wall; and the restriction part comprises projecting parts spaced from each other in a second direction perpendicular to the first direction.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a division of U.S. application Ser. No. 14/546,710, filed Nov. 18, 2014, which claims priority under 35 U.S.C. §119 from Japanese Patent Applications No. 2013-238350, filed on Nov. 18, 2013 and No. 2013-238351, filed on Nov. 18, 2013. The entire subject matter of each of these applications is incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    Technical Field 
         [0003]    Aspects of the present invention relate to a developing cartridge attached to an image forming apparatus of an electrophotographic type. 
         [0004]    Related Art 
         [0005]    Conventionally, a developing cartridge attached to an image forming apparatus of an electrophotographic type is known. For example, the developing cartridge of this type includes a frame, a developing roller and a supply roller supported by the frame, and a driving unit which is disposed on a left side of the frame and is configured to transmit a driving force to the developing roller and the supply roller. The frame includes a developing roller support groove which supports both ends of the developing roller in the left and right direction. 
         [0006]    For example, assembling of the developing cartridge is performed by attaching the supply roller to the frame in a state where a jig is inserted into the developing roller support groove to restrict movement of the frame, and by attaching the developing roller and the driving unit to the frame after removing the jig from the developing roller support groove. 
       SUMMARY 
       [0007]    That is, in the above described assembling work of the developing cartridge, the developing roller support groove cannot be used to restrict movement of the frame after the developing roller is attached to the frame. Therefore, the assembling work of the developing cartridge tends to become unstable and troublesome. 
         [0008]    Aspects of the present invention are advantageous in that they provide a developing cartridge capable of achieving smooth assembling work. 
         [0009]    According to an aspect of the invention, there is provided a developing cartridge, comprising: a housing configured to store developer; a developing roller; a drive mechanism configured to transmit a driving force to the developing roller; and a restriction part configured to restrict movement of the housing when the restriction part engages with an external member. The housing comprises: a first side wall; and a second side wall disposed to face the first side wall while being spaced from the first side wall in a first direction in which a rotation axis of the developing roller extends. The drive mechanism is disposed to the second side wall. The restriction part is disposed to the first side wall. The restriction part comprises a pair of first projecting parts facing with each other while being spaced from each other in a second direction which is perpendicular to the first direction. 
         [0010]    According to another aspect of the invention, there is provided a developing cartridge, comprising: a developing roller configured to be rotatable about a rotation axis extending in a first direction; a supply roller configured to be rotatable, to supply the developer to the developing roller and contacting the developing roller; and a housing configured to store the developer. The housing comprises: a first container unit configured to contain the developing roller and the supply roller; and a second container unit configured to store the developer therein and to be disposed adjacent to the first container unit on one side in a second direction which is perpendicular to the first direction. The housing further comprises: a pair of first walls disposed to be spaced from each other in the first direction; a second wall configured to connect the pair of first walls in the first direction; a conveying rib to protrude from the second wall to an outside of the housing, and configured to guide conveying of a recording medium; and a pair of engagement parts protruding from the second wall to the outside of the housing in a direction in which the conveying rib protrudes, and to restrict movement of the housing when the pair of engagement parts engage with an external member. The second wall extends in the second direction to form the first container unit and the second container unit. The pair of engagement parts are disposed closer to the second container unit in the second direction than a rotation center of the supply roller. A tip end of the conveying rib is positioned on an opposite side of an outer surface of the second wall with respect to each of tip ends of the pair of engagement parts. 
     
    
     
       BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS 
         [0011]      FIG. 1  is a perspective view of a developing cartridge according to an embodiment viewed from the upper left side. 
           [0012]      FIG. 2  is a perspective view of the developing cartridge shown in  FIG. 1  viewed from the upper right side. 
           [0013]      FIG. 3  is a perspective view of a housing shown in  FIG. 1  viewed from the upper left side. 
           [0014]      FIG. 4  is a bottom view of the developing cartridge shown in  FIG. 1 . 
           [0015]      FIG. 5  is a cross sectional view of the developing cartridge cut along a line A-A shown in  FIG. 4 . 
           [0016]      FIG. 6  is a right side view of the developing cartridge shown in  FIG. 2 . 
           [0017]      FIG. 7  is a cross sectional view of the developing cartridge cut along a line B-B shown in  FIG. 6 . 
           [0018]      FIG. 8  illustrates a state where a pair of engagement bossed of the housing shown in  FIG. 3  engages with a first restriction unit. 
           [0019]      FIG. 9  illustrates a state where the first restriction part and a second restriction part of the housing shown in  FIG. 8  engage with a second restriction unit. 
           [0020]      FIG. 10  is a central cross section of a printer provided with the developing cartridge shown in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    Hereafter, an embodiment according to the invention will be described with reference to the accompanying drawings. 
         [0022]    Outline of Developing Cartridge 
         [0023]    As shown in  FIGS. 1 and 5 , a developing cartridge  1  includes a housing  2 , an agitator  3 , a supply roller  5 , a developing roller  4  and a layer thickness limit blade  6 . 
         [0024]    In the following explanation, when directions of the developing cartridge  1  is referred to, a side on which the developing roller  4  is disposed is defined as a rear side of the developing cartridge  1 , and an opposite side of the rear side is defined as a front side of the developing cartridge  1 . That is, the left side on the paper face of  FIG. 5  is the rear side of the developing cartridge  1 , and the right side on the paper face of  FIG. 5  is the front side. Furthermore, the upper side on the paper face of  FIG. 5  is an upper side of the developing cartridge  1 , and the lower side on the paper face of  FIG. 5  is the lower side of the developing cartridge  1 . Left and right sides of the developing cartridge  1  are defined with reference to a state where the developing cartridge  1  is viewed from the front side. That is, the forehand side with respect to the paper face of  FIG. 5  is the left side of the developing cartridge  1 , and the back side with respect to the paper face of  FIG. 5  is the right side of the developing cartridge  1 . These sides are indicated specifically by arrows in the drawings. 
         [0025]    As shown in  FIG. 1 , the housing  2  is formed in a box-shape extending in the left and right direction, and stores toner therein. The rear end part of the housing  2  is opened in the front and rear direction. 
         [0026]    As shown in  FIG. 5 , the agitator  3  is disposed on the front portion in the housing  2 . The supply roller  5  is disposed on the lower rear side of the agitator  3  in the housing  2 , and is rotatably supported in the housing  2 . The developing roller  4  is disposed on the upper rear side of the supply roller  5  and at the rear end portion of the housing  2 . The lower front edge of the developing roller  4  is pressed against the upper rear edge of the supply roller  5 . The upper part and the rear part of the developing roller  4  are exposed from the housing  2 . The developing roller  4  is rotatably supported in the housing  2 . 
         [0027]    The layer thickness limit blade  6  is disposed on the upper front side of the developing roller  4 . The lower edge of the layer thickness limit blade  6  contacts the front edge of the developing roller  4 . 
         [0028]    2. Overall Configuration of Printer 
         [0029]    As shown in  FIG. 10 , the developing cartridge  1  is mounted on a printer  15 . The printer  15  is a monochrome printer of an electrophotographic type. The printer  15  includes a main body casing  16 , a process cartridge  17 , a scanner unit  18 , a fixing unit  19  and a paper conveying guide  20 . 
         [0030]    The main body casing  16  is formed in a box-shape. The main body casing  16  includes an opening  21 , a front cover  22 , a paper supply tray  23  and a discharge tray  24 . 
         [0031]    The opening  21  penetrates through a front wall of the main body casing  16  in the front and rear direction, and lets the process cartridge  17  to pass therethrough. The front cover  22  is a plate-like member formed in a letter of “L” when viewed as a side view. The front cover  22  is swingably supported by the front wall of the main body casing  16  around the lower end thereof acting as a fulcrum. The front cover  22  is configured to open or close the opening  21 . 
         [0032]    The paper supply tray  23  is disposed in the bottom portion of the main body casing  16 . The paper supply tray  23  is configured to store therein recording media, such as sheets of paper S. The discharge tray  24  is disposed on the upper surface of the main body casing  16 . The discharge tray  24  is formed to be recessed downward from the upper surface of the main body casing  16  so that the sheet of paper S is placed thereon. 
         [0033]    The process cartridge  17  is detachably attachable to the main body casing  16  via the opening  21 . The process cartridge  17  is disposed at the central portion in the up and down direction of the main body casing  16  in a state where the process cartridge  17  is attached to the main body casing  16 . The process cartridge  17  includes a drum cartridge  25  and the above described developing cartridge  1 . 
         [0034]    The drum cartridge  25  includes a drum frame  32 , a photosensitive drum  26 , a scorotron charger  27 , a transfer roller  28  and a pinch roller  36 . 
         [0035]    The drum frame  32  is a bottomed frame-like member having a rectangular shape when viewed as a plan view. A bottom wall of the drum frame  32  has a passing port  33 . The passing port  33  is disposed at a central portion in the front and rear direction of the bottom wall of the drum frame  32 . The passing port  33  has the shape and the size allowing the sheet of paper S to pass therethrough, and penetrates the bottom wall of the drum frame  32  in the up and down direction. 
         [0036]    The photosensitive drum  26  is disposed at the rear edge portion of the drum cartridge  25 , and has a cylindrical shape extending in the left and right direction. The photosensitive drum  26  is rotatably supported by the drum frame  32 . The scorotron charger  27  is disposed on the rear side of the photosensitive drum  26  and is spaced from the photosensitive drum  26 . 
         [0037]    The transfer roller  28  is disposed on the lower side of the photosensitive drum  26 . The transfer roller  28  contacts the lower edge of the photosensitive drum  28 . The pinch roller  36  has a cylindrical shape extending in the left and right direction, and is disposed to adjoin to the front edge of the passing port  33  from the rear side. The pinch roller  36  is rotatably supported by the drum frame  32 . 
         [0038]    The developing cartridge  1  is configured to be detachably attachable to the drum frame  32 . In the state where the developing cartridge  1  is attached to the drum frame  32 , the rear edge of the developing roller  4  contacts the front edge of the photosensitive drum  26 . 
         [0039]    The scanner unit  18  is disposed on the upper side of the process cartridge  17 . As shown by a dashed line in  FIG. 10 , the scanner unit  18  is configured to emit a laser beam based on image data to the photosensitive drum  26 . 
         [0040]    The fixing unit  19  is disposed on the rear side of the process cartridge  17  and is spaced from the process cartridge  17 . The fixing unit  19  includes a heat roller  29  and a pressure roller  30 . The pressure roller  30  is disposed on the lower rear side of the heat roller  29 , and is pressed against the lower rear edge of the heat roller  29 . 
         [0041]    The paper conveying guide  20  is configured to guide the sheet of paper S to pass from the paper supply tray  23  to a position between the photosensitive drum  26  and the transfer roller  28 , and to reach the fixing unit  19 . The paper conveying guide  20  is disposed to extend in the front and rear direction in a portion between the process cartridge  17  and the paper supply tray  23  in the up and down direction. Further, the paper conveying guide  20  includes a groove  34  and a registration roller  35 . 
         [0042]    The groove  34  is disposed in a central portion in the front and rear direction of the paper conveying guide  20 . The groove  34  has a rectangular shape when viewed as a side view, and is formed to be recessed downward from the upper surface of the paper conveying guide  20 . Further, the groove  34  is formed to receive the lower rear edge part of the process cartridge  17  attached to the main body casing  16 . 
         [0043]    The registration roller  35  is disposed on the front side of the groove  34  and is spaced from the registration roller  35  and the groove  34 . The registration roller  35  has a cylindrical shape extending in the left and right direction, and is rotatably supported by the paper conveying guide  20 . Further, the upper edge of the registration roller  35  contacts the lower edge of the pinch roller  36  attached to the process cartridge  17 . 
         [0044]    The upper surface of the paper conveying guide  20  and a part of the bottom wall of the drum frame  32  on the front side of the passing port  33  define a conveying path P. The conveying path P is configured such that the sheet of paper S supplied from the paper supply tray  23  passes from the upper front side to the lower rear side while proceeding toward the space between the pinch roller  36  and the registration roller  35 . 
         [0045]    When image formation operation is started under control of a control unit (not shown) in the printer  15 , the scorotron charger  27  charges uniformly the surface of the photosensitive drum  26 . Thereafter, the scanner unit  18  exposes the surface of the photosensitive drum  26 . As a result, an electrostatic latent image based on the image data is formed on the surface of the photosensitive drum  26 . 
         [0046]    The agitator  3  agitates the toner in the housing  2 , and supplies the agitated toner to the supply roller  5 . The supply roller  5  supplies the toner supplied from the agitator  3  to the developing roller  4 . At this time, the toner is frictionally charged positively between the developing roller  4  and the supply roller  5 , and is held on the developing roller  4 . The layer thickness limit blade  6  limits the thickness of the toner held on the developing roller  4  to a constant value. Further, the developing roller  4  supplies the toner, which is held thereon in a constant thickness, to the surface of the photosensitive drum  26 . As a result, a toner image is held on the surface of the photosensitive drum  26 . 
         [0047]    By rotations of the various rollers, the sheet of paper S is sent to the conveying path P from the paper supply tray  23 . After passing through the conveying path P, the sheet of paper S is sent to the space between the photosensitive drum  26  and the transfer roller  28  one by one at predetermined timing while passing through the passing port  33 . At this time, a conveying rib which is described later guides the sheet of paper S which has passed through the passing port  33  to proceed to the position between the photosensitive drum  26  and the transfer roller  28 . 
         [0048]    The toner image on the photosensitive drum  26  is transferred to the sheet of paper S when the sheet of paper S passes through the position between the photosensitive drum  26  and the transfer roller  28 . Thereafter, the sheet of paper S heated and pressed when the sheet of paper S passes through the position between the heat roller  29  and the pressure roller  30 . At this time, the tone image on the sheet of paper S is thermally fixed on the sheet of paper S. Then, the sheet of paper S is discharged to the discharge tray  24 . 
         [0049]    3. Details about Developing Cartridge 
         [0050]    The housing  2  is made of resin, and includes a first frame  40  and a second frame  41 . 
         [0051]    (1) First Frame 
         [0052]    The first frame  40  forms a lower part of the housing  2 . As shown in  FIGS. 3 and 5 , the first frame  40  includes a pair of side walls  45 , a front wall  49  and a bottom wall  50 . 
         [0053]    The pair of side walls  45  are both edge parts of the first frame  40  in the left and right direction and are disposed to have an interval therebetween. Specifically, the pair of side walls  45  include a right side wall  48  and a left side wall  47 . 
         [0054]    As shown in  FIG. 3 , the right side wall  48  is a right edge part of the first frame  40 . As shown in  FIG. 6 , the right side wall  48  is a plate-like member having a rectangular shape extending in the front and rear direction when viewed as a side view, and includes a developing chamber side wall  51  and a reservoir side wall  52  which are integrally provided. 
         [0055]    The developing chamber side wall  51  is a rear part of the right side wall  48 , and has a rectangular shape when viewed as a side view. As shown in  FIG. 3 , the developing chamber side wall  51  has a developing shaft insertion hole  53  and a supply shaft insertion hole  54 . 
         [0056]    The developing shaft insertion hole  53  has a shape of a letter “C” opened toward the rear side when viewed as a side view, and is recessed frontward from the center in the up and down direction of the rear edge of the developing chamber side wall  51 . The supply shaft insertion hole  54  is disposed on the lower front side with respect to the developing shaft insertion hole  53 . The supply shaft insertion hole  54  has a rectangular shape when viewed as a side view, and is formed to penetrate the developing chamber side wall  51  in the left and right direction. Further, the developing shaft insertion hole  53  and the supply shaft insertion hole  54  are formed to communicate with each other in a direction connecting from the lower front side to the upper rear side. 
         [0057]    As shown in  FIG. 6 , the reservoir side wall  52  is a front part of the right side wall  48 , and has a rectangular shape extending in the front and rear direction when viewed as a side view. The reservoir side wall  52  includes a main body  59 , a welding part  62 , a reinforcement rib  63 , a first restriction part  60  and a second restriction part  61 , which are integrally provided. 
         [0058]    The main body  59  is a plate-like member having a rectangular shape extending in the front and rear direction when viewed as a side view, and is formed to extend continuously from the front edge of the developing chamber side wall  51  to the front side. As shown in  FIG. 7 , the welding part  62  protrudes from the upper edge of the main body  59 , and, as shown in  FIG. 6 , extends over the entire main body  59  in the front and rear direction. 
         [0059]    The reinforcement rib  63  is disposed on the right surface of the main body  59 , and has a U-shape opened toward the upper side when viewed as a side view. The reinforcement rib  63  is formed to reinforce the right side wall  48 , and includes a front part  63 A, a lower part  63 B and a rear part  63 C. 
         [0060]    The front part  63 A protrudes rightward from the front edge of the main body  59 , and extends from the front edge of the welding part  62  to the lower edge of the main body  59  along the front edge of the main body  59 . The lower part  63 B protrudes rightward from the lower edge of the main body  59 , and continuously extends from the lower edge of the front part  63 A to the central part in the front and rear direction along the lower edge of the main body  59 . The rear part  63 C protrudes rightward from the central part in the front and rear direction of the main body  59 , and continuously extends to the upper side from the rear edge of the lower part  63 B to the central part of the main body  59  when viewed as a side view. As shown in  FIG. 7 , the size of the reinforcement rib  63  in the left and right direction is smaller than the size of the welding part  62  in the left and right direction. 
         [0061]    The first restriction part  60  is exposed when viewed from the right side, and is disposed in the front part of the right surface of the main body  59  such that the first restriction part  60  is surrounded by the wielding part  62  and the reinforcement rib  63  when viewed as a right side view. Specifically, the first restriction part  60  is disposed on a lower side with respect to the welding part  62  to be spaced from the welding part  62 , is disposed on the rear side with respect to the front part  63 A of the reinforcement rib  63  to be spaced from the lower part  63 B, is disposed on the upper side with respect to the lower part  63 B of the reinforcement rib  63  to be spaced from the lower part  63 B, and is disposed on the front side with respect to the rear part  63 C of the reinforcement rib  63  to be spaced from the rear part  63 C. 
         [0062]    The first restriction part  60  has a rectangular ringed shape extending in the front and rear direction when viewed in the left and right direction, and protrudes rightward from the right surface of the main body  59 . As shown in  FIG. 7 , the size in the left and right direction of the first restriction part  60  is smaller than the size in the left and right direction of the reinforcement rib  63 . That is, the right edge of the reinforcement rib  63  is disposed on the outside (i.e., on the right side) in the left and right direction relative to the right edge of the first restriction part  60 . 
         [0063]    As shown in  FIG. 6 , the first restriction part  60  includes a pair of first restriction walls  65  and a pair of second restriction walls  64 . The pair of first restriction walls  65  are disposed to face with each other in the front and rear direction to have an interval therebetween. The first restriction walls  65  linearly extend in the up and down direction when viewed as a side view. 
         [0064]    The second restriction walls  64  are disposed to face with each other to have an interval therebetween. The second restriction walls  64  linearly extend in the front and rear direction when viewed as a side view. Of the pair of second restriction walls  64 , the upper second restriction wall  64  connects the upper edges of the pair of first restriction walls  65  in the front and rear direction, and the lower second restriction wall  64  connects the lower edges of the pair of first restriction walls  65  in the front and rear direction. 
         [0065]    The second restriction part  61  is exposed when viewed from the right side, and is disposed on the rear side on the right surface of the main body  59  such that the second restriction part  61  is disposed on an opposite side of the first restriction part  60  with respect to the rear part  63 C of the reinforcement rib  63 . Further, the second restriction part  61  is disposed to overlap with the first restriction part  60  when viewed in the front and rear direction. 
         [0066]    The second restriction part  61  has a rectangular ringed shape when viewed in the left and right direction, and protrudes rightward from the right surface of the main body  59 . That is, the first restriction part  60  and the second restriction part  61  are disposed on the right side of the right side wall  48  which is disposed on the opposite side with respect to the left side wall  47 . The size in the left and right direction of the second restriction part  61  is substantially equal to the size in the left and right direction of the first restriction part  60 . 
         [0067]    The second restriction part  61  includes a pair of first restriction walls  67  and a pair of second restriction walls  66 . The first restriction walls  67  face with each other in the front and rear direction to have an interval therebetween. Each of the first restriction walls  67  extends in the up and down direction when viewed as a side view. The size of the first restriction wall  67  of the second restriction part  61  in the up and down direction is substantially equal to the size of the first restriction wall  65  of the first restriction part  60  in the up and down direction. 
         [0068]    The pair of second restriction walls  66  face with each other in the up and down direction to have an interval therebetween. Each of the second restriction walls  66  extends linearly in the front and rear direction when viewed as a side view. The size of the second restriction wall  66  of the second restriction part  61  in the front and rear direction is smaller than the size of the second restriction wall  64  of the first restriction part  60  in the front and rear direction. Of the pair of second restriction walls  66 , the upper second restriction wall  66  connects the upper edges of the pair of first restriction walls  67  in the front and rear direction, and the lower second restriction wall  66  connects the lower edges of the pair of first restriction walls  67  in the front and rear direction. 
         [0069]    A virtual line L passing the central parts of the pair of first restriction walls  65  in the up and down direction and the central parts of the pair of second restriction walls  67  in the up and down direction overlaps with a developing roller shaft  9  when viewed in the left and right direction. 
         [0070]    As shown in  FIG. 3 , the left side wall  47  is the left edge part of the first frame  40 , and is disposed to face the right side wall to have an interval therebetween. The left side wall  47  is a plate-like member having a rectangular shape extending in the front and rear direction when viewed as a side view, and includes a developing chamber side wall  70  and a reservoir side wall  71 . 
         [0071]    The developing chamber side wall  70  is a rear part of the left side wall  47 , and has a rectangular shape when viewed as a side view. Further, the developing chamber side wall  70  has a developing shaft insertion hole  72  and a supply shaft insertion hole  73 . 
         [0072]    The developing shaft insertion hole  72  is disposed to coincide with the developing shaft insertion hole  53  of the right side wall  48  when viewed in the left and right direction. The developing shaft insertion hole  72  has a shape of a letter “C” opened toward the rear side when viewed as a side view, and is recessed frontward from the center in the up and down direction of the rear edge of the developing chamber side wall  70 . The supply shaft insertion hole  73  is disposed to coincide with the supply shaft insertion hole  54  of the right side wall  48  when viewed in the left and right direction. The supply shaft insertion hole  73  has a rectangular shape when viewed as a side view, and penetrates the developing chamber side wall  70  in the left and right direction. 
         [0073]    The reservoir side wall  71  is the front part of the left side wall  47 , and extends continuously to the front side from the front edge of the developing chamber side wall  70 . The reservoir side wall  71  has a rectangular shape extending in the front and rear direction when viewed as a side view. Further, the reservoir side wall  71  has a toner filling opening  74 . 
         [0074]    The toner filling opening  74  is disposed in the front portion of the reservoir side wall  71 . The toner filling opening  74  has a circular shape when viewed as a side view, and penetrates the reservoir side wall  71  in the left and right direction. As a result, the toner filling opening  74  communicates with a toner reservoir  7  (which is described later) in the left and right direction. A cap (not shown) is detachably attachable to the toner filling opening  74 , and the toner filling opening  74  is closed by the cap. 
         [0075]    As shown in  FIG. 5 , the front wall  49  is the front edge part of the first frame  40 , and is provided to extend between the front edges of the left side wall  47  and the right side wall  48 . The front wall  49  is a plate-like member having a rectangular shape extending in the left and right direction when viewed as a front view. As shown in  FIG. 3 , the front wall  49  has a grip part  56 . The grip part  56  is disposed at a central portion in the left and right direction on the front surface of the front wall  49 . As shown in  FIG. 8 , the grip part  56  is formed in a letter “U” opened toward the lower side when viewed as a front view, and protrudes frontward from the front surface of the front wall  49 . 
         [0076]    The bottom wall  50  is the lower edge part of the first frame  40 , and is provided to extend between the lower edges of the left side wall  47  and the right side wall  48 . That is, the bottom wall  50  connects the pair of side walls  45  in the left and right direction. Further, the front edge of the bottom wall  50  is connected to the lower edge of the front wall  49 . Specifically, the bottom wall  50  is formed to extend in the front and rear direction, and includes a bending part  83 , an arc part  84  and a lip part  85 , which are integrally provided. 
         [0077]    The bending part  83  is the front part of the bottom wall  50 . The bending part  83  is formed to bend such that the central portion thereof in the front and rear direction is oriented to the lower side, and includes a front bending part  83 A and a rear bending part  83 B. The front bending part  83 A is the front part of the bending part  83 , and is formed to be continuously bent toward the lower rear side from the lower edge of the front wall  49 . The rear bending part  83 B is the rear part of the bending part  83 , and is formed to linearly and continuously extend to the upper rear side from the rear edge of the front bending part  83 A when viewed as a side view. 
         [0078]    The arc part  84  is disposed to adjoin the bending part  83  from the rear side. The arc part  84  has a shape of a semicircle opened to the upper side when viewed as a side view. The inner circumferential surface of the arc part  84  is formed to along the circumferential surface of the supply roller  5 . 
         [0079]    Specifically, the arc part  84  includes a front arc part  84 A and a rear arc part  84 B. The front arc part  84 A is the front part of the arc part  84 , and is formed to continuously extend to the lower side from the rear edge of the rear bending part  83 B and then bend to the lower rear side. The rear arc part  84 B is the rear part of the arc part  84 , and is formed to continuously extend from the lower edge of the front arc part  84 A and then bend to the upper rear side. 
         [0080]    The lower surface of the rear bending part  83 B and the lower surface of the front arc part  84 A define a recessed part  80 . The recessed part  80  has a wedge-shape when viewed as a side view, and is recessed to the upper rear side to be oriented to the inside of the housing  2 . 
         [0081]    The rip part  85  is disposed to adjoin the arc part  84  from the rear side, and is formed to continuously extend to the lower rear side from the rear edge of the rear arc part  84 B. 
         [0082]    As shown in  FIG. 4 , the bottom wall  50  includes conveying ribs  90 , a pair of engagement bosses  91  and connection ribs  92 . 
         [0083]    As shown in  FIG. 5 , the conveying ribs  90  are disposed on the lower surface of the bottom wall  50 . Each conveying rib  90  has a plate-like shape, and protrudes to the lower side from the rear part of the lower surface of the bottom wall  50 , i.e., the conveying rib  90  protrudes to the outside of the housing  2 . Further, as shown in  FIG. 4 , each conveying rib  90  extends, in the front and rear direction, over a range from the front arc part  84 A to the rip part  85  when viewed as a bottom view. The plurality of conveying ribs  90  are aligned in the left and right direction to have intervals therebetween. Specifically, twelve conveying ribs  90  are aligned. 
         [0084]    As shown in  FIG. 5 , the lower edge of the conveying rib  90  includes a bending edge  90 A, a first slanting edge  90 B and a second slanting edge  90 C. The bending edge  90 A is the front part of the lower edge of the conveying rib  90 , has a shape of a letter “C” when viewed as a side view, and is recessed to the upper rear side from the lower edge of the conveying rib  90 . The bending part  90 A is formed to be along the outer circumferential surface of the pinch roller  36 . 
         [0085]    The first slanting edge  90 B extends to be inclined to the lower rear side continuously from the rear edge of the bending edge  90 A. The second slanting edge  90 C extends to be inclined to the upper rear side continuously from the rear edge of the first slanting edge  90 B. 
         [0086]    As shown in  FIG. 10 , the conveying ribs  90  configured as described above overlap with the passing port  33  of the drum frame  32  when viewed from the lower side in the state where the developing cartridge  1  is attached to the drum frame  32 . 
         [0087]    As shown in  FIGS. 4 and 5 , the pair of engagement bosses  91  are respectively disposed on the both sides of the plurality of conveying ribs  90  in the left and right direction to sandwich the plurality of conveying ribs  90  between the pair of engagement bosses  91 , and are disposed to coincide with each other when viewed in the left and right direction. 
         [0088]    The pair of engagement bosses  91  are respectively disposed at the both edge parts of the recesses part  80  in the left and right direction, and are formed to protrude downward from the lower surface of the rear bending part  83 B. That is, the engagement bosses  91  protrude to the outside of the housing  2  from the rear bending part  83 B along the direction in which the conveying ribs  90  protrude. 
         [0089]    As shown in  FIG. 5 , the pair of engagement bosses  91  are disposed to entirely overlap with the conveying ribs  90  when viewed in the left and right direction, and the lower edges of the engagement bosses  91  are positioned on the upper side with respect to the lower edges of the conveying ribs  90 . That is, the lower edges of the conveying ribs  90  are positioned on the opposite side of the lower surface of the rear bending part  83 B with respect to the lower edges of the engagement bosses  91 . 
         [0090]    As shown in  FIG. 4 , of the pair of engagement bosses  91 , the left engagement boss  91 L is disposed on the left side of the leftmost one of the plurality of conveying ribs  90  to have an interval with respect to the leftmost one of the plurality of conveying ribs  90 . As shown in  FIGS. 4 and 5 , the left engagement boss  91 L has a cylindrical shape extending in the up and down direction, and protrudes downward from the left edge part of the lower surface of the rear bending part  83 B. 
         [0091]    An inner circumferential surface of the left engagement boss  91 L is defined as a first hollow part  93 . That is, the first hollow part  93  is recessed upward toward the inside of the housing  2  from the lower edge of the left engagement boss  91 L. As shown in  FIG. 4 , the first hollow part  93  has a circular shape when viewed from the upper side. Further, as shown in  FIG. 5 , the rear bending part  83 B is inclined, and therefore the first hollow part  93  has a shallow part  93 A and a deep part  93 B. 
         [0092]    The shallow part  93 A is a front part of the first hollow part  93 , and the size of the shallow part  93 A in the up and down direction is smaller than the inner diameter of the first hollow part  93 . The deep part  93 B is a rear part of the first hollow part  93 , and the size of the deep part  93 B in the up and down direction is larger than the inner diameter of the first hollow part  93 . 
         [0093]    As shown in  FIG. 4 , of the pair of engagement bosses  91 , the right engagement boss  91 R is disposed on the right side of the rightmost one of the plurality of conveying ribs  90  to have an interval with respect to the rightmost one of the plurality of conveying ribs  90 . The right engagement boss  91 R has an elliptical cylinder shape extending in the up and down direction, and protrudes downward from the right edge part of the lower surface of the rear bending part  83 B. 
         [0094]    An inner circumferential surface of the right engagement boss  91 R is defined as a second hollow part  94 . That is, the second hollow part  94  is recessed upward toward the inside of the housing  2  from the lower edge of the right engagement boss  91 R. The second hollow part  94  has an elliptical shape extending in the left and right direction when viewed in the up and down direction. The short diameter of the second hollow part  94  is substantially equal to the inner diameter of the first hollow part  93 , and the longer diameter of the second hollow part  94  is larger than the inner diameter of the first hollow part  93 . As in the case of the first hollow part  93 , the second hollow part  94  has a deep part whose size in the up and down direction is larger than the short diameter and a shallow part whose size in the up and down direction is smaller than the short diameter. 
         [0095]    The connection rib  92  is disposed between the engagement boss  91  and the conveying rib  90  adjoining the engagement rib  91 . Two connection ribs  92  are provided for the pair of engagement bosses  91 , respectively. The connection rib  92  has a plate-like shape extending in the left and right direction and is formed to extend linearly when viewed as a bottom view. The connection rib  92  connects the inner edge of the engagement boss  91  in the left and right direction and the adjoining conveying rib  90 . The upper edge of the connection rib  92  is connected to the lower surface of the rear bending part  83 B. 
         [0096]    (2) Second Frame 
         [0097]    As shown in  FIG. 3 , the second frame  41  is an upper part of the housing  2 , and covers the first frame  40  from the upper side. The second frame  41  is a plate-like member having a rectangular shape extending in the left and right direction when viewed as a plan view. The second frame  41  is integrally provided with an upper front wall  86  and an upper rear wall  87 . 
         [0098]    The upper front wall  86  is a front part of the second frame  41 , and includes an expanded part  88  and a jaw part  89 . As shown in  FIG. 5 , the expanded part  88  has a box-shape opened toward the lower side, and is formed to extend in the left and right direction (see  FIG. 3 ). 
         [0099]    The jaw part  89  is disposed on the both sides in the left and right direction and the front side with respect to the expanded part  88 . That is, the jaw part  89  has shape of a letter “U” opened to the rear side when viewed as a plan view. The jaw part  89  is connected to the lower edge of the expanded part  88 . 
         [0100]    As shown in  FIG. 5 , the upper rear wall  87  is a rear part of the second frame  41 , and includes a slanting wall  95  and a partition wall  96 . The slanting wall  95  is a plate-like member having a rectangular shape extending in the left and right direction when viewed as a plan view, and is formed to extend to the rear side continuously from the lower edge of a rear wall of the expanded part  88  and to be bent and inclined to the lower rear side. 
         [0101]    The partition wall  96  is disposed closely to the slanting wall  95  on the rear side of the slanting wall  95 . The partition wall  96  is a plate-like member having a rectangular shape extending in the left and right direction when viewed as a rear view. Further, as shown in  FIG. 5 , a central part in the up and down direction of the front surface of the partition wall  96  is connected to the rear edge of the slanting wall  95 . 
         [0102]    (3) Housing 
         [0103]    As shown in  FIGS. 2, 3 and 5 , the housing  2  is configured by combining the first frame  40  and the second frame  41  and by welding the upper edge of the reservoir side wall  71  of the left side wall  47 , the welding part  62  of the reservoir side wall  52  of the right side wall and the upper edge of the front wall  49  to the jaw part  89  of the upper front wall  86 . 
         [0104]    With this configuration, as shown in  FIG. 5 , the second frame  41  is disposed on the upper side of the of the bottom wall  50  to be spaced from the bottom wall  50 , and connects the upper edges of the pair of side walls  45  in the left and right direction. Further, the front arc part  84 A of the bottom wall  50  extends from the front edge of the rear arc part  84 B to the front side to approach the second frame  41 . The rear bending part  83 B extends continuously from the front edge of the front arc part  84 A to the front side to depart from the second frame  41 . 
         [0105]    In the housing  2 , the lower edge of the partition wall  96  and a connection part  98  of the bending part  83  and the arc part  84  are disposed to be spaced in a direction connecting the upper rear side and the lower front side. In a side cross sectional view of the housing  2 , a rear space with respect to a virtual line L 1  connecting the lower edge of the partition wall  96  and the upper edge of the connection part  98  is defined as a developing chamber  8 , and a front space with respect to the virtual line L 1  is defined as the toner reservoir  7  which stores the toner. 
         [0106]    The lower edge of the partition wall  96 , the upper edge of the connection part  98  and the left and right inner surfaces of the left side wall  47  and the right side wall  48  define a communication hole  99 . That is, the housing  2  has the toner reservoir  7  and the developing chamber  8  which are disposed close to each other in the front and rear direction, and the communication hole  99  which communicates the toner reservoir  7  and the developing chamber  8  in the front and rear direction. 
         [0107]    (4) Developing Chamber 
         [0108]    Specifically, as shown in  FIGS. 3 and 5 , the developing chamber  8  is defined as by the developing chamber side wall  51  of the right side wall  48 , the developing chamber side wall  70  of the left side wall  47  and the arc part  84  and the lip part  85  of the bottom wall  50 . 
         [0109]    As shown in  FIG. 5 , the developing cartridge  1  includes the developing roller  4 , the supply roller  5  and the layer thickness limit blade  6  in the developing chamber  8 . 
         [0110]    The developing roller  4  is disposed in the lower edge part of the developing chamber  8 , and is disposed on the upper side of the lip part  85  to be spaced from the lip part  85 . The developing roller  4  includes the developing roller shaft  9  and a rubber roller  10 . 
         [0111]    The developing roller shaft  9  is made of metal, and has a circular column shape extending in the left and right direction. The rubber roller  10  has a cylindrical shape, and covers the developing roller shaft  9  such that the left and right ends of the developing roller shaft  9  are exposed. 
         [0112]    The developing roller  4  is supported by the housing  2  such that the right end of the developing roller shaft  9  is rotatably supported by the developing chamber side wall  51  and the left end of the developing chamber  9  is rotatably supported by the developing chamber wall  70 . With this configuration, the developing roller  4  is able to rotate with respect to the housing  2  about a center axis A 1  of the developing roller shaft  9 . Further, the right end of the developing roller shaft  9  protrudes rightward from the developing chamber side wall  51  via the developing shaft insertion hole  53 , and the left end of the developing roller shaft  9  protrudes leftward from the developing chamber side wall  70  via the developing shaft insertion hole  72 . 
         [0113]    The supply roller  5  is disposed on the lower front side of the developing roller  4  in the developing chamber  8 , and is housed in the arc part  84 . The supply roller  5  includes a supply roller shaft  11  and a sponge roller  12 . 
         [0114]    The supply roller shaft  11  is made of metal, and has a circular column shape extending in the left and right direction. The sponge roller  12  has a cylindrical shape, and covers the supply roller shaft  11  such that left and right ends of the supply roller shaft  11  are exposed. 
         [0115]    The supply roller  5  is supported by the housing  2  such that the right end of the supply roller shaft  11  is rotatably supported by the developing chamber side wall  51  and the left end of the supply roller shaft  11  is rotatably supported by the developing chamber side wall  70 . With this configuration, the supply roller  5  is able to rotate, with respect to the housing  2 , about a center axis A 2  of the supply roller shaft  11 . Further, the right end of the supply roller shaft  11  protrudes rightward via the supply shaft insertion hole  54  with respect to the developing chamber side wall  51 , and the left end of the supply roller shaft  11  protrudes leftward via the supply shaft insertion hole  73  with respect to the developing chamber side wall  70 . 
         [0116]    The layer thickness limit blade  6  is disposed on the upper front side of the developing roller  4  in the developing chamber  8 . As shown in  FIG. 1 , the layer thickness limit blade  6  is a plate-like member having a rectangular shape extending in the left and right direction when viewed as a rear view. Further, as shown in  FIG. 5 , the layer thickness limit blade  6  is supported by the rear surface of the partition wall  96  such that the lower edge of the layer thickness limit blade  6  contacts the front edge of the circumferential surface of the rubber roller  10 . 
         [0117]    (5) Toner Reservoir 
         [0118]    Specifically, as shown in  FIGS. 3 and 5 , the toner reservoir  7  is defined by the reservoir side wall  52  of the right side wall  48 , the reservoir side wall  71  of the left side wall  47 , the bending part  83  of the bottom wall  50 , the front wall  49  and the second frame  41 . 
         [0119]    As shown in  FIG. 5 , the developing cartridge  1  includes the agitator  3  in the toner reservoir  7 . The agitator  3  includes an agitator shaft  13  and an agitating blade  14 . 
         [0120]    The agitator shaft  13  is made of resin, and includes a shaft body  100  and a blade support unit  101 . The shaft body  100  has a circular column shape extending in the left and right direction. The blade support unit  101  has a shape of a letter “U”, and an opened-side end thereof is connected to the shaft body  100 . With this configuration, the blade support unit  101  extends, from the shaft body  100 , outward in the radial direction of the shaft body  100 . 
         [0121]    The agitating blade  14  is formed of an elastic film member. Te agitating blade  14  has a rectangular shape extending in the left and right direction. further, one edge of the agitating blade  14  is fixed to an outer part in the radial direction of the blade support unit  101 . With this configuration, the agitating blade  14  is supported by the agitator shaft  13 . 
         [0122]    The agitator  3  is supported by the housing  2  such that the eight end of the shaft body  100  is rotatably supported by the reservoir side wall  52  and the left end of the shaft body  100  is rotatably supported by the reservoir side wall  71 . With this configuration, the agitator  3  is able to rotate, with respect to the housing  2 , about a center axis A 3  of the shaft body  100 . The left end of the shaft body  100  protrudes leftward from the reservoir side wall  71  of the left side wall  47 . 
         [0123]    (6) Relative Disposition of First Restriction Part, Second Restriction Part and Engagement Boss with respect to Center Axis of Agitator 
         [0124]    As shown in  FIG. 5 , the first restriction part  60  is disposed on the front side with respect to the center axis A 3  of the agitator  3 , i.e., an opposite side of the developing chamber  8 , when viewed in the left and right direction, and the second restriction part  61  is disposed between the developing chamber  8  and the center axis A 3  of the agitator  3  in the front and rear direction. 
         [0125]    Each of the pair of engagement bosses  91  is disposed on the front side with respect to the center axis A 2  of the supply roller  5 , i.e., on the toner reservoir  7  side, and is disposed between the developing chamber  8  and the center axis A 3  of the agitator  3  in the front and rear direction. each of the pair of engagement bosses  91  is disposed closer to the center axis A 1  of the developing roller  4  relative to the center axis A 3  of the agitator  3 . That is, an interval between the center axis Al of the developing roller  4  and the shaft center of the engagement boss  91  in the front and rear direction is slightly smaller than an interval between the center axis A 3  of the agitator  3  and the shaft center of the engagement boss  91 . 
         [0126]    (7) Drive Unit and Electrode Unit 
         [0127]    As shown in  FIGS. 1 and 2 , the developing cartridge  1  includes a drive unit  105  and a power supply unit  120 . As shown in  FIG. 1 , the drive unit  105  is configured to transmit a driving force to the developing roller  4 , the supply roller  5  and the agitator  3 . The drive unit  105  is disposed, closely to the left side wall  47 , on the left side with respect to the left side wall  47 , i.e., on an opposite side of the right side wall  48 . The drive unit  105  includes a gear train  106  and a gear cover  107 . The gear train  106  includes a developing coupling  109 , a developing gear  108 , a supply gear (not shown) and an agitator gear (not shown). 
         [0128]    The developing gear  109  is disposed on the left surface of the developing chamber side wall  70  of the left side wall  47 . The developing coupling  109  is supported by the developing chamber side wall  70  so as to be able to rotate about a rotation shaft (not shown). The developing coupling  109  has a circular column shape extending in the left and right direction. An outer circumferential surface of the right part of the developing coupling  109  has gear teeth over the entire circumferential surface thereof. 
         [0129]    The developing coupling  109  has a coupling recession  110 . The coupling recession  110  is disposed on the left end surface of the developing coupling  109 . The coupling recession  110  has a circular shape when viewed as a side view, and is recessed rightward from the left end face of the developing coupling  109 . Further, the coupling recession  110  is configured such that a main body coupling (not shown) is inserted to the coupling recession  110  to be unable to rotate relative to the coupling recession  110 . 
         [0130]    The developing gear  108  is attached to the left end of the developing roller shaft  9  so as to be unable to rotate relative to the developing roller shaft  9 . Further, the developing gear  108  engages with the gear teeth of the developing coupling  109 . The supply gear (not shown) is attached to the left end of the supply roller shaft  11  so as to be unable to rotate relative to the supply roller shaft  11 . The supply gear (not shown) engages with the gear teeth of the developing coupling  109 . The agitator gear (not shown) is attached to the left end of the shaft body  100  of the agitator  3  so as to be unable to rotate relative to the shaft body  100 . The agitator gear (not shown) is coupled to the developing coupling  109  via an idle gear (not shown). 
         [0131]    The gear cover  107  has a box-shape opened toward the right side, and has the size that the gear cover  107  is able to entirely cover the gear train  106 . Further, the left wall of the gear cover  107  has an exposing hole  111 . The exposing hole  111  has a circular shape when viewed as a side view, and penetrates through the left wall of the gear cover  107  in the left and right direction. 
         [0132]    The gear cover  107  is screwed to the left surface of the left side wall  47  so as to let the coupling recession  110  of the developing coupling  109  be exposed via the exposing hole  111  and to cover entirely the gear train  106 . 
         [0133]    As shown in  FIG. 2 , the power supply unit  120  is disposed, on the right side of the right side wall  48 , closely to the right side wall  48 . The power supply unit  120  includes a supply electrode  122 , an insulating member  125  and a developing electrode  121 . 
         [0134]    The supply electrode  122  is made of conductive resign material, and is supported by the right surface of the developing chamber side wall  51  of the right side wall  48 . Although not shown in the drawings, the supply electrode  122  is electrically connected to the right end of the supply roller  11 . Further, the supply electrode  122  includes a supply side contact  126 . The supply side contact  126  is configured to be electrically connected to a main body side supply electrode (not shown) which the main body casing  16  includes. The supply side contact  126  has a shape of a rectangular cylinder of which right end is closed and which extends in the left and right direction. 
         [0135]    The insulating member  125  is made of insulating resin material, and is fixed to the developing chamber side wall  51  on the right side of the supply electrode  122 . The insulating member  125  includes an insulating part  123 . The insulating part  123  is disposed, on the rear side of the supply side contact  126 , closely to the supply side contact  126 . When viewed as a side view, the insulating part  123  has a shape of an L-shaped rectangular cylinder of which right end is closed and which extends in the left and right direction. 
         [0136]    The developing electrode  121  is made of conductive material, and is supported by the insulating part  125  on the right side of the insulating part  125 . The developing electrode  121  includes a developing side contact  127  and a developing shaft collar part  128 . 
         [0137]    The developing side contact  127  is configured to be electrically connected to a main body side developing electrode (not shown) which the main body casing  16  includes, and is disposed on the lower rear side of the insulating part  123 . The developing side contact  127  has a shape of a rectangular cylinder of which right end is closed and which extends in the left and right direction. 
         [0138]    The developing shaft collar part  128  is disposed on the rear side of the developing side contact  127 . The developing shaft collar  128  has a cylindrical shape extending in the left and right direction, and rotatably receives the right end of the developing roller shaft  9 . 
         [0139]    4. Assembling Operation of Developing Cartridge 
         [0140]    Hereafter, an assembling operation for the developing cartridge  1  is explained with reference to  FIGS. 8 and 9 . Although  FIGS. 8 and 9  illustrates the state where the supply roller  5 , the developing roller  4 , the power supply unit  120  and the drive unit  105  are attached to the housing  2  for the sake of convenience, in an assembling process of the developing cartridge  1 , the supply roller  5 , the developing roller  4 , the power supply unit  120  and the drive unit  105  are sequentially attached to the housing  2  as described later. 
         [0141]    Although an assembling method of the developing cartridge is not particularly limited, the developing cartridge  1  is assembled, for example, by an automatic assembling line  190 . When the developing cartridge  1  is assembled by the automatic assembling line  190 , the assembling operation which is described later is implemented by an assembling robot. 
         [0142]    The automatic assembling line  190  includes a first restriction unit  201 , a second restriction unit  203  and an arm  200 . 
         [0143]    As shown in  FIG. 8 , the first restriction unit  201  includes a first support plate  205  and a pair of first pillar parts  202 . The first support plate  205  is a plate-like member having a rectangular shape extending in the left and right direction when viewed as a plan view. The pair of first pillar parts  202  are provided respectively for the pair of engagement bosses  91 , and are disposed on the upper surface of the first support plate  205 . The pair of first pillar parts  202  have rectangular column shapes extending in the up and down direction, and are formed to extend upward from the both end parts of the upper surface of the first support plate  205  in the left and right direction. Further, although not shown in the drawings, each of the first pillar parts  202  has a projection. The projection (not shown) has a circular column shape extending in the up and down direction, and is formed to extend upward from a central part of the upper surface of the first pillar part  202  when viewed as a plan view. The outer diameter of the projection (not shown) is substantially equal to the inner diameter of the first hollow part  93 . 
         [0144]    As shown in  FIG. 9 , the second restriction unit  203  includes a second support plate  206  and a pair of second pillar parts  204 . The second support plate  206  is a plate-like member having a rectangular shape extending in the front and rear direction. The pair of second pillar parts  204  are provided respectively for the first restriction part  60  and the second restriction part  61 , and are disposed on the upper surface of the second support plate  206 . The pair of second pillar parts  204  have rectangular column shapes extending in the up and down direction, and are formed to extend upward from the both end parts of the upper surface of the second support plate  206  in the left and right direction. Further, although not shown in the drawings, each of the second pillar parts  204  has a projection. The projection (not shown) circular column shape extending in the up and down direction, and is formed to extend upward from a central part of the upper surface of the second pillar parts  204  when viewed as a plan view. The outer size of the projection (not shown) is substantially equal to the inner size of the second restriction part  61 . 
         [0145]    As shown in  FIG. 8 , the arm  200  has a J-shape when viewed as a side view, and is formed to extend in the left and right direction. The arm  200  is configured to sandwich the lower edge of the grip part  56  and the upper edge of the expanded part  88  by advancing from the front side to the rear side with respect to the developing cartridge  1 . With this configuration, the arm  200  is able to hold the developing cartridge  1 . 
         [0146]    As shown in  FIGS. 3, 4 and 8 , in order to assemble the developing cartridge  1 , first, a worker disposed the housing  2  on the upper side of the first restriction unit  201  such that the first hollow part  93  of the left engagement boss  91 L receives the projection of the left first pillar part  202  and the second hollow part  94  of the right engagement boss  91 R receives the projection of the right first pillar part  202 . As a result, the relative movement of the housing  2  in the horizontal direction with respect to the first restriction unit  201  is restricted. 
         [0147]    Next, as shown in  FIGS. 3 and 5 , the supply roller  5  is attached to the housing  2  such that the left and right ends of the supply roller  11  are respectively inserted into the corresponding ones of the supply shaft insertion holes  54  and  73 . Then, the developing roller  4  is attached to the housing  2  such that the both ends in the left and right direction of the developing roller shaft  9  are respectively inserted into the corresponding ones of the developing shaft insertion holes  53  and  72 . 
         [0148]    Next, as shown in  FIGS. 3 and 6 , the supply electrode  122 , the insulating member  125  and the developing electrode  121  are sequentially attached to the developing chamber side wall  51  of the right wall  48  from the right side. 
         [0149]    Thereafter, as shown in  FIG. 8 , the arm  200  approaches the housing  2  from the front side, and engages with the housing  2  such that the arm  200  sandwiches the lower edge of the grip part  56  and the upper edge of the expanded part  88 . As a result, the housing  2  is held by the arm  200 . The arm  200  lifts upward the housing  2 , and releases the engagement of the pair of engagement bosses  91  and the pair of first pillar parts  202 . 
         [0150]    Next, the arm  200  rotates the housing  2  by approximately  90  degrees in the clockwise direction when viewed as a plan view in the state of holding the housing  2  so that the longer direction of the housing  2  is disposed to be along the up and down direction. as a result, the right side wall  48  of the housing  2  is positioned on the lower side and the left side wall  47  of the housing  2  is positioned on the upper side. 
         [0151]    Then, as shown in  FIGS. 6 and 9 , the housing  2  is disposed on the upper side of the second restriction unit  203  such that the second restriction part  61  receives the projection of the front second pillar part  204  and the second restriction part  61  receives the projection of the rear second pillar part  204 . As a result, movement of the housing  2  in the horizontal direction with respect to the second restriction unit  203  is restricted. 
         [0152]    Next, a toner filling device (not shown) fills the toner into the toner reservoir  7 , along the up and down direction, from the toner filling opening  74 , and thereafter the tone filling opening  74  is closed with a cap (not shown). 
         [0153]    Thereafter, as shown in  FIGS. 1 and 9 , the gear train  106  and the gear cover  107  are sequentially attached to the left side wall  47  from the upper side. 
         [0154]    Thus, the assembling work for the developing cartridge  1  is finished. 
         [0155]    5. Advantageous Effects 
         [0156]    (1) as shown in  FIG. 6 , the first restriction part  60  and the second restriction part  61  are disposed, on the right side of the right side wall, closely to the right side wall  48 , i.e., opposite to the left side wall  47 . Therefore, as shown in  FIG. 9 , during assembling of the developing cartridge  1 , the pair of first restriction wall  65  and the pair of first restriction walls  67  can be respectively engaged with the second restriction unit  203 , and therefore movement of the housing  2  can be restricted. 
         [0157]    As a result, since the developing cartridge  1  can be assembled in the state where movement of the housing  2  is restricted, the assembling work for the developing cartridge  1  can be stabilized and smoothed. 
         [0158]    In particular, since the drive unit  105  is disposed, on the left side of the left side wall  47 , closely to the left side wall  47 , the drive unit  105  can be securely attached to the housing  2  in the state where the first restriction part  60  and the second restriction part  61  are engaged with the second restriction unit  203 . Therefore, the assembling work for the drive unit  105  can be smoothed. 
         [0159]    (2) As shown in  FIG. 6 , each of the first restriction part  60  and the second restriction part  61  defines a ringed shape when viewed in the left and right direction. Therefore, each of the first restriction part  60  and the second restriction part  61  can be securely engaged with the pair of second pillar parts  204 , and as a result movement of the housing  2  can be securely restricted. 
         [0160]    (3) As shown in  FIG. 3 , the left side wall  47  has the toner filling opening  74 . Therefore, as shown in  FIG. 9 , the toner can be filled into the inside of the housing  2  via the toner filling opening  74  in the state where the first restriction part  60  and the second restriction part  61  are engaged with the pair of second pillar parts  204 . As a result, the toner filling work for the housing  2  can be smoothed. 
         [0161]    (4) As shown in  FIG. 6 , the first restriction part  60  and the second restriction part  61  are disposed on the reservoir side wall  52  constituting the toner reservoir  7 . Therefore, the first restriction part  60  and the second restriction part  61  can be easily disposed. In particular, as shown in  FIG. 9 , when the first restriction part  60  and the second restriction part  61  engage the pair of second pillar parts  204 , movement of the toner reservoir  7  of the housing  2  can be securely restricted. As a result, when the toner is filled into the inside of the housing  2  via the toner filling opening  74 , the housing  2  can be stably supported. 
         [0162]    (5) As shown in  FIG. 5 , the second restriction part  61  is disposed between the developing chamber  8  and the center axis A 3  of the agitator  3  when viewed in the left and right direction. Therefore, be causing the second restriction part  61  to engage with the second pillar part  204 , a relatively heavy part of the developing cartridge  1  can be securely supported. As a result, the developing cartridge  1  can be stably supported in a well-balanced manner. 
         [0163]    (6) As shown in  FIG. 5 , the first restriction part  60  is disposed on the front side with respect to the center axis A 3  of the agitator  3 , and the second restriction part  61  is disposed on the rear side with respect the center axis A 3  of the agitator  3 , therefore, by causing the first restriction part  60  and the second restriction part  61  engage with the pair of second pillar parts  204 , movement of the developing cartridge  1  is securely prevented. 
         [0164]    (7) As shown in  FIG. 6 , the first restriction part  60  is surrounded by the welding part  62  and the reinforcement rib  63  when viewed in the left and right direction. Therefore, the first restriction part  60  is protected by the welding part  62  and the reinforcement rib  63 . As a result, it becomes possible to prevent the first restriction part  60  from being damaged, for example, when a person accidentally lets the developing cartridge  1  drop down. 
         [0165]    (8) As shown in  FIG. 7 , the right edge of the reinforcement rib  63  is positioned on the right side with respect to the right edge of the first restriction wall  65 . Therefore, when a person accidentally lets the developing cartridge  1  drop down, it is possible to prevent the right edge of the reinforcement rib  63  from crashing against, for example, a floor, and thereby to prevent the right edge of the first restriction wall  65  from crashing against, for example, a floor. As a result, it is possible to securely prevent the first restriction part  60  from being damaged. 
         [0166]    (9) As shown in  FIG. 5 , the pair of engagement bosses  91  protrude downward from the lower surface of the rear bending part  83 B of the bottom wall  50 . That is, the engagement bosses  91  and the conveying ribs  90  protrude together to the lower side from the bottom wall  50 . 
         [0167]    Therefore, as shown in  FIG. 8 , during the assembling of the developing cartridge  1 , the pair of engagement bosses  91  can be engaged with the pair of first pillar parts  202  of the first restriction unit  201 . As a result, movement of the housing  2  in the horizontal direction with respect to the first restriction unit can be restricted. 
         [0168]    Furthermore, as shown in  FIG. 5 , the pair of engagement bosses  91  are disposed on the front side, i.e., on the toner reservoir  7  side, with respect to the center axis A 2  of the supply roller  5 . Therefore, when the pair of engagement bosses  91  are engaged with the pair of first pillar parts  202 , the developing cartridge  1  can be supported in a well-balanced manner. As a result, the assembling work for the developing cartridge  1  can be stabilized and smoothed. 
         [0169]    Furthermore, the lower edge of the conveying rib  90  is positioned on the lower side with respect to the lower edge of the engagement boss  91 , i.e., on an opposite side of the lower surface of the bottom wall  50  with respect to the lower edge of the engagement boss  91 . Therefore, as shown in  FIG. 10 , when the conveying ribs  90  guide conveying of the sheet of paper S, the pair of engagement bosses  91  can be prevented from contacting the sheet of paper S. 
         [0170]    (10) As shown in  FIG. 5 , each of the pair of engagement bosses  91  is disposed between the developing chamber  8  and the center axis A 3  of the agitator  3  in the front and rear direction. Therefore, as shown in  FIG. 8 , by engaging the pair of engagement bosses  91  with the pair of first pillar parts  202 , a relatively heavy part of the developing cartridge  1  can be securely supported. As a result, the developing cartridge  1  can be securely supported. 
         [0171]    (11) As shown in  FIG. 5 , the pair of engagement bosses  91  are disposed closer to the center axis A 1  of the developing roller  4  than the center axis A 3  of the agitator  3 . Therefore, as shown in  FIG. 8 , by engaging the pair of engagement bosses with the pair of first pillar parts  202 , the relatively heavy part of the developing cartridge  1  can be supported more securely. 
         [0172]    (12) As shown in  FIG. 5 , the pair of engagement bosses  91  are disposed in the recessed part  80  which is recessed upward to the inside of the housing  2 . Therefore, the protruding amount of the engagement boss  91  can be increased while suppressing increase in size of the developing cartridge  1  in the up and down direction. As a result, reliable engagement between the engagement boss  91  and an external member can be secured while suppressing increase in size of the developing cartridge. 
         [0173]    (13) As shown in  FIG. 5 , the bottom wall  50  has the front arc part  83 A and the rear bending part  83 B, and the outer surface of the front arc part  83 A and the outer surface of the rear bending part  83 B constitute the recessed part  80 . Since the engagement bosses  91  are disposed on the outer surface of the rear bending part  83 B which is on the toner reservoir  7  side with respect to the front arc part  84 A, the engagement bosses  91  can be securely disposed on the toner reservoir  7  side with respect to the center axis A 2  of the supply roller  5 . 
         [0174]    (14) Since, as shown in  FIG. 4 , the plurality of conveying ribs  90  are aligned in parallel to have intervals therebetween in the left and right direction, conveying of the sheet of paper S can be securely guided. 
         [0175]    Furthermore, the conveying ribs  90  disposed at both ends in the left and right direction and the pair of engagement bosses  91  are connected by the connection ribs  92 , respectively. Therefore, the conveying rib  90  and the engagement boss  91  which are connected together can be securely reinforced. 
         [0176]    (15) As shown in  FIG. 5 , each of the pair of engagement bosses  90  is disposed to entirely overlap with the conveying rib  90  when viewed in the left and right direction, Therefore, as shown in  FIG. 10 , when the conveying ribs  90  guide conveying of the sheet of paper S, the pair of engagement bosses  91  can be securely prevented from contacting the sheet of paper S. as a result, more smooth conveying of the sheet of paper S can be secured. 
         [0177]    (16) As shown in  FIG. 4 , the left engagement boss  91 L has the first hollow part  93 , and the right engagement boss  91 R has the second hollow part  94 . Therefore, since the first hollow part  93  and the second hollow part  94  respectively receive the projections (not shown) of the pair of first pillar parts  202  as shown in  FIG. 8 , the pair f engagement bosses  91  and the pair of first pillar parts  202  can be securely engaged with each other. 
         [0178]    Furthermore, since, as shown in  FIG. 4 . the second hollow part  94  has an elliptical shape elongated in the left and right direction when viewed from the lower side, shift in the left and right direction is accepted when the pair of engagement bosses  91  are engaged with the pair of first pillar parts  202 . 
         [0179]    (17) As shown in  FIG. 5 , the first hollow part  93  has the deep part whose size in the up and down direction is larger than the inner diameter of the first hollow part  93 . Therefore, the first hollow part  93  is able to securely received the projection of the left first pillar part  202 . 
         [0180]    6. Variation 
         [0181]    (1) As shown in  FIG. 9 , in the above described embodiment, movement of the housing  2  is restricted by the first restriction part  60  and the second restriction part  61 ; however, the embodiment is not limited to such a configuration. Movement of the housing  2  may also be restricted by the first restriction part  60  and the second restriction part  61  when toner is filled again into the used developing cartridge  1 . 
         [0182]    In this case, the drive unit  105  is removed from the second wall  47  after the housing  2  is disposed such that the longer direction of the housing  2  is along the up and down direction, and the first restriction part  60  and the second restriction part  61  are engaged with the pair of second pillar parts  204 . Then, the cap (not shown) is removed from the toner filling opening  74 , and the toner is filled into the toner reservoir  7  via the toner filling opening  74 . 
         [0183]    (2) As shown in  FIGS. 8 and 9 , in the above described embodiment, the developing cartridge  1  is assembled on the automatic assembling line  190 ; however, the embodiment is not limited to such a configuration. The developing cartridge  1  may be assembled manually using the first restriction unit  201  and the second restriction unit  202 . 
         [0184]    (3) In the above described embodiment, the developing cartridge  1  is configured to be detachably attachable to the drum frame  32  of the drum cartridge  25 ; however, the embodiment is not limited to such a configuration. For example, the developing cartridge  1  may be formed integrally with the drum cartridge  25 . In this case, the process cartridge  17  in which the developing cartridge  1  and the drum cartridge  25  are integrally provided corresponds to an example of a developing cartridge. 
         [0185]    (4) In pace of the above described developing roller  4 , for example, a brush roller, a magnetic roller or the like may be employed. 
         [0186]    (5) The above described first restriction part  60  may be formed as a separate member provided separately from the right side wall  48  of the housing  2 , and may be attached to the reservoir side wall  52  of the right side wall  48 . In the first restriction part  60 , the pair of second restriction walls  64  may not be provided. 
         [0187]    (6) The above described second restriction part  61  may be formed as a separate member provided separately from the right side wall  48  of the housing  2 , and may be attached to the reservoir side wall  52  of the right side wall  48 . In the second restriction part  61 , the pair of second restriction walls  66  may not be provided. With this configuration, the same advantageous effects of the above described embodiment can also be achieved. 
         [0188]    (7) The above described pair of engagement bosses  91  may be formed as separate members which are separately provided from the bottom wall  50  of the housing  2 , and may be formed to be attached to the bottom wall  50 . 
         [0189]    (8) The above described pair of second restriction walls  64  may be formed as separate members which are provided separately from the right side wall of the housing  2 , and may be attached to the reservoir side wall  52  of the right side wall  52 . 
         [0190]    (9) The shapes of the first hollow part  93  and the second hollow part  94  are not limited to the above described circular shape and the elliptical shape, but may be a polygonal shape. 
         [0191]    It is understood that the above described embodiment and the variations can be appropriately combined.