Patent Publication Number: US-10788772-B2

Title: Process unit including main unit and toner cartridge

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/242,504, filed Jan. 8, 2019, which is a continuation of U.S. patent application Ser. No. 15/889,460, filed Feb. 6, 2018, which further claims priority from Japanese Patent Application No. 2017-071034 filed Mar. 31, 2017. The entire contents of all the above applications are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     This disclosure relates to a process unit. 
     BACKGROUND 
     Conventionally, a process unit having a main unit and a toner cartridge mountable on the main unit is known. 
     A main unit includes a photosensitive drum and a developing unit. The developing unit includes a developing roller. The developing unit has an opening for receiving a toner supplied from a toner cartridge. The toner cartridge has an opening for discharging a toner in the inside. The opening of the toner cartridge faces the opening of the developing unit in a state where the toner cartridge is mounted on the main unit. The toner cartridge includes a shutter that is movable between an open position in which the opening is opened, and a closed position in which the opening is closed. The shutter is moved between the open position and the closed position by operation by a user, in a state where the toner cartridge is mounted on the main unit. 
     SUMMARY 
     According to one aspect, this specification discloses a process unit. The process unit includes a main unit and a toner cartridge. The main unit includes a drum unit and a developing unit. The drum unit has a photosensitive drum. The developing unit has a developing roller and a developing frame supporting the developing roller. The developing frame has an insertion opening. The toner cartridge is configured to be mounted on the main unit. The toner cartridge includes a toner supply pipe and a first shutter. The toner supply pipe has a toner supply opening. The toner supply pipe is configured to, when the toner cartridge is mounted onto the main unit, move through the insertion opening from an outside position at which the toner supply opening is located outside the developing frame to an inside position at which the toner supply opening is located inside the developing frame. The first shutter is provided at the toner supply pipe. The first shutter is configured to move relative to the toner supply pipe between an open position at which the toner supply opening is opened and a closed position at which the toner supply opening is closed. The first shutter is configured to move relative to the toner supply pipe from the closed position to the open position in a state where the toner supply pipe is located at the inside position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments in accordance with this disclosure will be described in detail with reference to the following figures wherein: 
         FIG. 1  is a cross-sectional view of a process unit of this disclosure, and is a cross-sectional view taken along line C-C of  FIG. 7 ; 
         FIG. 2  is a side view of the process unit shown in  FIG. 1 , wherein in order to illustrate the insides of a toner recovery pipe and a toner recovery box, the toner recovery pipe and the toner recovery box are shown as a cross section taken along line A-A shown in  FIG. 4 ; 
         FIG. 3  is an explanatory diagram for explaining opening and closing operation of a first shutter shown in  FIG. 1 , and shows a state where a toner supply pipe is located at an inside position and the first shutter is located at a closed position; 
         FIG. 4  is a plan view of a main unit shown in  FIG. 1 , wherein in order to illustrate an inside of an insertion space, a part of a developing frame is shown as a cross section; 
         FIG. 5  is a cross-sectional view taken along line B-B of  FIG. 4 ; 
         FIG. 6A  is an explanatory diagram for explaining movement of a developing unit with respect to a photosensitive drum, and shows a state where a developing roller is still; 
         FIG. 6B  is an explanatory diagram for explaining movement of the developing unit with respect to the photosensitive drum, together with  FIG. 6A , and shows a state where the developing roller is rotating; 
         FIG. 7  is a plan view of a toner cartridge shown in  FIG. 1 ; 
         FIG. 8A  is a cross-sectional view taken along line C-C of  FIG. 7 ; 
         FIG. 8B  is a cross-sectional view taken along line D-D of  FIG. 8A ; 
         FIG. 9A  is a side view of a toner supply pipe viewed from an axial direction; 
         FIG. 9B  is a side view of the toner supply pipe viewed from an opposite direction from the direction of  FIG. 9B  in the axial direction; 
         FIG. 10  is an explanatory diagram for explaining a use mode of a process unit shown in  FIG. 1 ; 
         FIG. 11  is a plan view of a main unit of a process unit of a second embodiment, wherein in order to illustrate an inside of an insertion space, a part of a developing frame is shown as a cross section; 
         FIG. 12  is a cross-sectional view taken along line E-E of  FIG. 11 ; 
         FIG. 13  is a plan view of a toner cartridge of the process unit of the second embodiment; 
         FIG. 14  is an explanatory diagram for explaining opening and closing operation of a first shutter of the toner cartridge shown in  FIG. 13 , and shows a state where a toner supply pipe is located at an inside position, and a first shutter is located at a closed position; and 
         FIG. 15  is an explanatory diagram for explaining the opening and closing operation of the first shutter, together with  FIG. 14 , and shows a state where the toner supply pipe is located at the inside position, and the first shutter is located at the open position. 
     
    
    
     DETAILED DESCRIPTION 
     In the process unit described above, there is a problem that, when a shutter moves, a part of a toner discharged from an opening of a toner cartridge is not received by an opening of a developing unit, and stains the developing unit. 
     An example of the object of this disclosure is to provide a process unit that prevents a developing unit from being stained when a toner cartridge is mounted on a main unit. 
     1. Outline of Process Unit 
     The outline of a process unit  1  will be described. 
     As shown in  FIG. 1 , the process unit  1  includes a main unit  2 , and a toner cartridge  3 . The toner cartridge  3  is mountable on the main unit  2 . The toner cartridge  3  is detachable from the main unit  2 . 
     The main unit  2  includes a drum unit  4 , a developing unit  5 , and a toner recovery pipe  6  (see  FIG. 2 ). 
     1.1 Drum Unit 
     The drum unit  4  includes a photosensitive drum  7 , a charging roller  8 , a cleaner  9 , and a cleaning frame  10 . 
     The photosensitive drum  7  is configured so that a toner image is formed on a surface of the photosensitive drum  7 . The photosensitive drum  7  is configured to rotate about a rotation axis A 1  extending in an axial direction. 
     The charging roller  8  is configured to charge the surface of the photosensitive drum  7 . The charging roller  8  contacts the surface of the photosensitive drum  7 . 
     The cleaner  9  is configured to remove a toner from the photosensitive drum  7 . The cleaner  9  contacts the surface of the photosensitive drum  7 . The cleaner  9  extends in the axial direction. The cleaner  9  has a plate shape. 
     The cleaning frame  10  accommodates the toner removed from the photosensitive drum  7  by the cleaner  9 . 
     1.2 Developing Unit 
     The developing unit  5  is configured to supply the toner supplied from the toner cartridge  3 , to the photosensitive drum  7 . The detailed configuration of the developing unit  5  will be described later. The developing unit  5  includes a developing roller  11  and a supply roller  25 . 
     The developing roller  11  is configured to supply the toner in the developing unit  5  to the photosensitive drum  7 . The developing roller  11  contacts the surface of the photosensitive drum  7 . The developing roller  11  may be in proximity to a circumferential surface of the photosensitive drum  7  with a space therebetween. The developing roller  11  is configured to rotate about a rotation axis A 2  extending in the axial direction. Specifically, the developing roller  11  includes a roller body  11 A and a shaft  11 B. 
     The roller body  11 A extends in the axial direction. The roller body  11 A is formed of a conductive rubber. The roller body  11 A has a columnar shape. The roller body  11 A contacts the surface of the photosensitive drum  7 . In a case where the developing roller  11  is in proximity to the circumferential surface of the photosensitive drum  7  with a space therebetween, the roller body  11 A is in proximity to the circumferential surface of the photosensitive drum  7  with a space therebetween. 
     The shaft  11 B extends along the rotation axis A 2  of the developing roller  11 . The shaft  11 B is formed of a metal. 
     The supply roller  25  is configured to supply the toner in the developing unit  5  to the developing roller  11 . The supply roller  25  contacts a circumferential surface of the developing roller  11 . 
     1.3 Toner Recovery Pipe 
     As shown in  FIG. 2 , the toner recovery pipe  6  recovers the toner from the cleaning frame  10  (see  FIG. 1 ) into a toner recovery box  18  described later. The toner recovery pipe  6  has a toner discharge opening  12 . Specifically, the toner recovery pipe  6  includes a screw  13 , an insertion cylinder  14  having the toner discharge opening  12 , a shutter  15 , and a spring  16 . 
     The screw  13  is configured to convey the toner from the cleaning frame  10  to the toner recovery box  18 . The screw  13  is located inside the cleaning frame  10  (see  FIG. 4 ) and the toner recovery pipe  6 . 
     The insertion cylinder  14  is inserted in a receiving cylinder  20  of the toner cartridge  3  described later in a state where the toner cartridge  3  is mounted on the main unit  2 . The direction in which the insertion cylinder  14  is inserted in the receiving cylinder  20  is parallel to a first direction described later. Thereby, when the toner cartridge  3  is mounted onto the main unit  2 , the toner cartridge  3  is moved in the first direction with respect to the main unit  2 , and thereby, a toner supply pipe  61  (see  FIG. 1 ) described later is inserted in an insertion opening  46  (see  FIG. 1 ) described later, and the insertion cylinder  14  is inserted in the receiving cylinder  20 . Thereby, the toner cartridge  3  is smoothly mounted onto the main unit  2 . The toner discharge opening  12  communicates with a toner recovery opening  19  described later, in a state where the toner cartridge  3  is mounted on the main unit  2 . In this state, the toner discharge opening  12  discharges the toner conveyed by the screw  13 . The toner discharged from the toner discharge opening  12  is accommodated in the toner recovery box  18  through the toner recovery opening  19 . 
     The shutter  15  is movable relative to the insertion cylinder  14  between an open position (see  FIG. 2 ) at which the toner discharge opening  12  is opened, and a closed position (see  FIG. 4 ) at which the toner discharge opening  12  is closed. The shutter  15  is located at an outer surface of the insertion cylinder  14 . When the toner cartridge  3  is mounted onto the main unit  2 , the shutter  15  abuts the toner recovery box  18  in the mounting direction of the toner cartridge  3  relative to the main unit  2 , thereby moving from the closed position to the open position relative to the insertion cylinder  14 . When the toner cartridge  3  is detached from the main unit  2 , the shutter  15  is pressed by the spring  16 , thereby moving from the open position to the closed position with respect to the insertion cylinder  14 . 
     The spring  16  is configured to press the shutter  15  located at the open position toward the closed position. The spring  16  contacts the shutter  15 . 
     1.4 Toner Cartridge 
     As shown in  FIG. 1 , the toner cartridge  3  is configured to supply the toner to the developing unit  5 . The detailed configuration of the toner cartridge  3  will be described later. The toner cartridge  3  includes a toner accommodation box  17 , an agitator  23 , the toner recovery box  18 , and an auger screw  24 . 
     In the toner accommodation box  17 , the toner supplied to the developing unit  5  is accommodated. 
     The agitator  23  is configured to agitate the toner in the toner accommodation box  17 . The agitator  23  is configured to supply the toner in the toner accommodation box  17  to the toner supply pipe  61  described later. The agitator  23  is located in the toner accommodation box  17 . The agitator  23  is configured to rotate about a rotation axis A 3  extending in the axial direction. 
     The toner accommodated in the cleaning frame  10  is recovered into the toner recovery box  18 . Specifically, as shown in  FIG. 2 , the toner recovery box  18  accommodates the toner conveyed by the toner recovery pipe  6 . The toner recovery box  18  has the toner recovery opening  19 . Specifically, as shown in  FIG. 7 , the length of the toner recovery box  18  in the axial direction is longer than the length of the toner accommodation box  17  in the axial direction. The toner recovery box  18  has a protruding portion  26  protruding farther than the toner accommodation box  17  in the axial direction. As shown in  FIG. 2 , the protruding portion  26  includes: the receiving cylinder  20  having the toner recovery opening  19 ; a shutter  21 ; and a spring  22 . 
     The receiving cylinder  20  receives the insertion cylinder  14  of the toner recovery pipe  6 , in a state where the toner cartridge  3  is mounted on the main unit  2 . 
     The shutter  21  is movable relative to the receiving cylinder  20  between an open position (see  FIG. 2 ) at which the toner recovery opening  19  is opened, and a closed position (see  FIG. 7 ) at which the toner recovery opening  19  is closed. The shutter  21  is located inside the receiving cylinder  20 . When the toner cartridge  3  is mounted onto the main unit  2 , the shutter  21  is pressed by the insertion cylinder  14 , thereby moving from the closed position to the open position relative to the receiving cylinder  20 . When the toner cartridge  3  is detached from the main unit  2 , the shutter  21  is pressed by the spring  22 , thereby moving from the open position to the closed position relative to the receiving cylinder  20 . 
     The spring  22  is configured to press the shutter  21  located at the open position toward the closed position. The spring  22  contacts the shutter  21 . 
     As shown in  FIG. 7 , the auger screw  24  is configured to convey the toner in the toner recovery box  18  in the axial direction. Specifically, the auger screw  24  is configured to convey the toner in the toner recovery box  18  toward a direction away from the toner recovery opening  19 , in the axial direction. The auger screw  24  is located in the toner recovery box  18 . The auger screw  24  extends in the axial direction. 
     2. Detail of Process Unit  1   
     Detail of the process unit  1  will be described below. 
     As shown in  FIG. 1 , the toner cartridge  3  includes the toner supply pipe  61  for supplying the toner to the developing unit  5 , and a first shutter  62 . The toner supply pipe  61  has a toner supply opening  65 . The first shutter  62  is movable relative to the toner supply pipe  61  between an open position (see  FIG. 1 ) at which the toner supply opening  65  is opened, and a closed position (see  FIG. 3 ) at which the toner supply opening  65  is closed. 
     The developing unit  5  includes a developing frame  41  having the insertion opening  46 . When the toner cartridge  3  is mounted onto the main unit  2 , the toner supply pipe  61  is inserted in the insertion opening  46 . Specifically, when the toner cartridge  3  is mounted onto the main unit  2 , the toner supply pipe  61  moves relative to the developing frame  41  from an outside position (see  FIG. 8A ) at which the toner supply opening  65  is located outside the developing frame  41  to an inside position (see  FIG. 1  and  FIG. 3 ) at which the toner supply opening  65  is located inside the developing frame  41 , through the insertion opening  46 . The first direction in which the toner supply pipe  61  moves from the outside position to the inside position is the same direction as the mounting direction of the toner cartridge  3  onto the main unit  2 . 
     At this time, as shown in  FIG. 1  and  FIG. 3 , the first shutter  62  moves relative to the toner supply pipe  61  from an closed position (see  FIG. 3 ) to an open position (see  FIG. 1 ) in a state where the toner supply pipe  61  is located at the inside position. 
     The detailed structures of the drum unit  4 , the developing unit  5 , and the toner cartridge  3  will be described below. 
     2.1 Drum Unit 
     As shown in  FIG. 4 , the drum unit  4  includes a drum side plate  31 A and a drum side plate  31 B. 
     The drum side plate  31 A, together with the drum side plate  31 B, supports the photosensitive drum  7  (see  FIG. 2 ) and the developing unit  5 . The drum side plate  31 A supports the toner recovery pipe  6 . The drum side plate  31 A is located between the toner recovery pipe  6  and the developing unit  5  in the axial direction. The toner recovery pipe  6  is attached to the drum side plate  31 A. The drum side plate  31 A extends in a direction perpendicular to the axial direction. The drum side plate  31 A has a first elongated hole  32  (see  FIG. 2 ), a second elongated hole  33  (see  FIG. 2 ), a guide  34 , and a positioning protrusion (not shown). That is, the drum unit  4  has the first elongated hole  32 . 
     As shown in  FIG. 2 , a first boss  47  of the developing unit  5  described later is inserted in the first elongated hole  32 . The first elongated hole  32  extends in a direction toward the photosensitive drum  7  or away from the photosensitive drum  7  in a direction perpendicular to the axial direction. More specifically, the first elongated hole  32  extends in the mounting direction. That is, the first elongated hole  32  extends in parallel to the first direction. 
     A second boss  48  of the developing unit  5  described later is inserted in the second elongated hole  33 . The second elongated hole  33  is located at the opposite side of the photosensitive drum  7  with respect to the first elongated hole  32 , in the mounting direction. The second elongated hole  33  extends in the same direction as the first elongated hole  32 . 
     As shown in  FIG. 4 , when the toner cartridge  3  is mounted onto the main unit  2 , the guide  34  guides the toner cartridge  3 , together with a guide  35  of the drum side plate  31 B described later. That is, the toner cartridge  3  is mountable onto the main unit  2  in a direction in which the guide  34  extends. The guide  34  extends in the mounting direction. A boss  72 A (see  FIG. 7 ) of the toner cartridge  3  described later is fitted into the guide  34 . 
     The positioning protrusion (not shown) engages the boss  72 A (see  FIG. 7 ) of the toner cartridge  3  described later, thereby positioning the toner cartridge  3  with respect to the main unit  2 . The positioning protrusion (not shown) is located in the guide  34 . The positioning protrusion (not shown) is located at a downstream end of the guide  34  in the mounting direction of the toner cartridge  3  onto the main unit  2 . The positioning protrusion (not shown) is formed of a leaf spring, as similar to a positioning protrusion  36  (see  FIG. 1 ) described later. 
     The drum side plate  31 B is located with a space with respect to the drum side plate  31 A in the axial direction. The drum side plate  31 B is located at the opposite side of the drum side plate  31 A with respect to the photosensitive drum  7  and the developing unit  5 , in the axial direction. The drum side plate  31 B extends in a direction perpendicular to the axial direction. The drum side plate  31 B has a third elongated hole (not shown), a fourth elongated hole (not shown), the guide  35 , and the positioning protrusion  36  (see  FIG. 1 ). 
     A third boss  49  of the developing unit  5  described later is inserted into the third elongated hole. The third elongated hole is located at the opposite side of the first elongated hole  32  (see  FIG. 2 ) with respect to the developing frame  41  described later, in the axial direction. The third elongated hole extends in the same direction as the first elongated hole  32 . 
     A fourth boss  50  of the developing unit  5  described later is inserted into the fourth elongated hole. The fourth elongated hole is located at the opposite side of the photosensitive drum  7  with respect to the third elongated hole in the mounting direction. The fourth elongated hole is located at the opposite side of the second elongated hole  33  (see  FIG. 2 ) with respect to the developing frame  41  described later, in the axial direction. The fourth elongated hole extends in the same direction as the first elongated hole  32 . 
     When the toner cartridge  3  is mounted onto the main unit  2 , the guide  35  guides the toner cartridge  3 , together with the guide  34  of the drum side plate  31 A. The guide  35  extends in the mounting direction. A boss  72 B (see  FIG. 7 ) of the toner cartridge  3  described later is fitted into the guide  35 . 
     As shown in  FIG. 1 , the positioning protrusion  36  engages the boss  72 B (see  FIG. 7 ) of the toner cartridge  3  described later, thereby positioning the toner cartridge  3  with respect to the main unit  2 . The positioning protrusion  36  is located at the guide  35 . The positioning protrusion  36  is located at a downstream end of the guide  35  in the mounting direction of the toner cartridge  3  onto the main unit  2 . The positioning protrusion  36  is formed of a leaf spring. 
     2.2 Developing Unit 
     As shown in  FIG. 4 , the developing unit  5  is located between the drum side plate  31 A and the drum side plate  31 B in the axial direction. The developing unit  5  includes the developing frame  41 , a seal member  42 , a protrusion  43 A, a protrusion  43 B, an auger screw  52 A (see  FIG. 5 ), and an auger screw  52 B (see  FIG. 5 ). 
     2.2.1 Developing Frame 
     The developing frame  41  is a frame of the developing unit  5 . The developing frame  41  supports the developing roller  11 . The developing frame  41  extends in the axial direction. The developing frame  41  has a one end E 1  and an other end E 2  located away from the one end E 1  in the axial direction. The one end E 1  is located closer to the drum side plate  31 A than to the drum side plate  31 B in the axial direction. The one end E 1  faces the drum side plate  31 A. The other end E 2  is located closer to the drum side plate  31 B than to the drum side plate  31 A in the axial direction. The other end E 2  faces the drum side plate  31 B. The developing frame  41  includes the first boss  47 , the second boss  48 , the third boss  49 , and the fourth boss  50 . 
     The first boss  47  is located at the one end E 1  of the developing frame  41 . As shown in  FIG. 2 , the first boss  47  is inserted in the first elongated hole  32  of the drum unit  4 . One end of the shaft  11 B of the developing roller  11  is inserted in the first boss  47 . The shaft  11 B is configured to rotate relative to the first boss  47 . The first boss  47  extends along the rotation axis A 2  of the developing roller  11 . The first boss  47  has a cylindrical shape. 
     The second boss  48  is located at the one end E 1  (see  FIG. 4 ) of the developing frame  41 . The second boss  48  is inserted in the second elongated hole  33  of the drum unit  4 . The second boss  48  is located at the opposite side of the photosensitive drum  7  with respect to the first boss  47  in the mounting direction. The second boss  48  extends in the axial direction. The second boss  48  has a cylindrical shape. The second boss  48  is pressed toward the photosensitive drum  7  by a spring  51  in the mounting direction. 
     As shown in  FIG. 4 , the third boss  49  is located at the other end E 2  of the developing frame  41 . The third boss  49  is inserted in the third elongated hole (not shown) of the drum unit  4 . An other end of the shaft  11 B of the developing roller  11  is inserted in the third boss  49 . The shaft  11 B is configured to rotate relative to the third boss  49 . The third boss  49  extends along the rotation axis A 2  (see  FIG. 2 ) of the developing roller  11 . The third boss  49  has a cylindrical shape. 
     The fourth boss  50  is located at the other end E 2  of the developing frame  41 . The fourth boss  50  is inserted in the fourth elongated hole (not shown) of the drum unit  4 . The fourth boss  50  is located at the opposite side of the photosensitive drum  7  (see  FIG. 2 ) with respect to the third boss  49  in the mounting direction. The fourth boss  50  extends in the axial direction. The fourth boss  50  has a cylindrical shape. The fourth boss  50  is pressed toward the photosensitive drum  7  by the spring (not shown) in the mounting direction. 
     The first boss  47  is inserted in the first elongated hole  32 , the second boss  48  is inserted in the second elongated hole  33 , the third boss  49  is inserted in the third elongated hole, and the fourth boss  50  is inserted in the fourth elongated hole. Thereby, the developing unit  5  is movable relative to the photosensitive drum  7  in the mounting direction. 
     The second boss  48  is pressed by the spring  51 , and the fourth boss  50  is pressed by a spring (not shown), and thereby, the developing unit  5  is pressed against the photosensitive drum  7  in the mounting direction. 
     As shown in  FIG. 6A , the roller body  11 A of the developing roller  11  is formed of a conductive rubber. Thus, the roller body  11 A is eccentric to an extent of an error due to processing accuracy. Therefore, when the developing roller  11  rotates in a state (see  FIG. 1 ) where the toner cartridge  3  is mounted on the main unit  2 , and the toner supply pipe  61  is located at the inside position, as shown in  FIG. 6B , the developing unit  5  moves relative to the photosensitive drum  7 , due to the eccentricity of the roller body  11 A. 
     At this time, that is, when the developing unit  5  moves relative to the photosensitive drum  7  in a state where the toner cartridge  3  is mounted on the main unit  2 , and the toner supply pipe  61  is located at the inside position, the developing frame  41  (see  FIG. 1 ) moves relative to the toner supply pipe  61  (see  FIG. 1 ). At this time, the toner supply pipe  61  remains located at the inside position. That is, the toner supply opening  65  of the toner supply pipe  61  remains located at the downstream side of the seal member  42  in the first direction, as described later. In other words, the toner supply opening  65  remains located inside the developing frame  41 . Thereby, the toner discharged from the toner supply opening  65  is prevented from staining an outer surface of the developing frame  41 , when the developing unit  5  moves relative to the photosensitive drum  7  in a state where the toner cartridge  3  is mounted on the main unit  2 , and the toner supply pipe  61  is located at the inside position. 
     At this time, the first boss  47  is guided by the first elongated hole  32 , the second boss  48  is guided by the second elongated hole  33 , the third boss  49  (see  FIG. 4 ) is guided by the third elongated hole, and the fourth boss  50  (see  FIG. 4 ) is guided by the fourth elongated hole. Since the first elongated hole  32 , the second elongated hole  33 , the third elongated hole and the fourth elongated hole extend in the mounting direction, the direction in which the developing unit  5  moves relative to the photosensitive drum  7  is parallel to the direction in which the toner supply pipe  61  moves between the inside position and the outside position. 
     As shown in  FIG. 4  and  FIG. 5 , the developing frame  41  has a developing chamber  44 , an insertion space  45 , an inner surface  45 A, and an insertion opening  46 . 
     The developing chamber  44  is an internal space of the developing frame  41 , and is a space where the toner to be supplied to the photosensitive drum  7  by the developing roller  11  is stored. The developing chamber  44  extends in the axial direction. A part of the developing roller  11  and the supply roller  25  are accommodated in the developing chamber  44 . 
     The insertion space  45  is an internal space of the developing frame  41 , and is a space in which the toner supply pipe  61  (see  FIG. 1 ) is inserted. The insertion space  45  is located closer to the one end E 1  of the developing frame  41  than to the other end E 2  of the developing frame  41 . The insertion space  45  communicates with the developing chamber  44 . The insertion space  45  is located above the developing chamber  44  in a state where the process unit  1  is mounted on an image forming apparatus  100  (see  FIG. 10 ) described later. 
     The inner surface  45 A is an inner surface of the developing frame  41 , and is an inner surface located at a downstream end of the insertion space  45  in the first direction. The inner surface  45 A is located with a space with respect to the seal member  42  in the first direction. The inner surface  45 A faces a downstream end E 32  (see  FIG. 1 ) of the toner supply pipe  61  with a space S therebetween in a state where the toner cartridge  3  is mounted on the main unit  2 . Thereby, as shown in  FIG. 6B , due to the movement of the developing unit  5  relative to the photosensitive drum  7 , even when the developing frame  41  moves relative to the toner supply pipe  61 , the toner supply pipe  61  is prevented from interfering with (abutting) the inner surface  45 A and disturbing the movement of the developing frame  41 . 
     The insertion opening  46  is an opening into which the toner supply pipe  61  is inserted when the toner cartridge  3  is mounted onto the main unit  2 . The insertion opening  46  is located at an upstream side of the insertion space  45  in the first direction. 
     2.2.2 Seal Member 
     As shown in  FIG. 1 , the seal member  42  seals between the developing frame  41  and the toner supply pipe  61  in a state where the toner supply pipe  61  is located at the inside position. As shown in  FIG. 5 , the seal member  42  is located in the insertion opening  46 . The seal member  42  extends in a direction intersecting the first direction. Preferably, the seal member  42  extends in a direction perpendicular to the first direction. The seal member  42  has elasticity. Specifically, the seal member  42  includes a seal layer  53  and a support layer  54 . The seal member  42  has a cutting C. 
     The seal layer  53  is provided for securing the sealing performance of the seal member  42 . The seal layer  53  is formed of, for example, a sponge, in order to reliably capture the toner. 
     The support layer  54  is provided for securing the elasticity of the seal member  42 . The support layer  54  is formed of, for example, a rubber or resin. The support layer  54  is located at the opposite side of the insertion space  45  with respect to the seal layer  53  in the first direction. 
     The cutting C is provided for forming an opening in a center portion of the seal member  42  when the toner supply pipe  61  moves from the outside position to the inside position. The cutting C is located at the center portion of the seal member  42 . Due to expansion of the cutting C, the opening is formed in the center portion of the seal member  42 . Thereby, the insertion opening  46  is opened. The shape and the number of the cutting C are not limited. 
     As shown in  FIG. 3 , the seal member  42  is deformed by being pressed by the toner supply pipe  61  when the toner supply pipe  61  moves from the outside position to the inside position. Thereby, the cutting C expands, and the opening is formed in the center portion of the seal member  42 . The toner supply pipe  61  passes the opening formed due to the expansion of the cutting C, and moves from the outside position to the inside position. As shown in  FIG. 1 , the seal member  42  contacts a circumferential surface of the toner supply pipe  61  in a state where the toner supply pipe  61  is located at the inside position. Thereby, the seal member  42  seals between the developing frame  41  and the toner supply pipe  61 . As shown in  FIG. 5 , the seal member  42  is restored by the elasticity of the seal member  42  when the toner supply pipe  61  moves from the inside position to the outside position. Thereby, due to the contraction of the cutting C, the formed opening is closed. Thereby, the seal member  42  closes the insertion opening  46  when the toner supply pipe  61  moves from the inside position to the outside position. 
     2.2.3 Protrusion 
     As shown in  FIG. 3 , the protrusion  43 A is configured to contact a rib  68 A (see  FIG. 8B ) of the first shutter  62  described later when the toner supply pipe  61  moves from the outside position to the inside position. As shown in  FIG. 4 , the protrusion  43 A is located inside the developing frame  41  and protrudes from the developing frame  41 . Specifically, the protrusion  43 A is located in the insertion space  45 . The protrusion  43 A protrudes from the inner surface of the developing frame  41  in the axial direction. The protrusion  43 A extends in the first direction. The protrusion  43 A has a downstream end E 11  and an upstream end E 12  in the first direction. The protrusion  43 A has a first contact surface  55 A at the upstream end E 12 . That is, the developing unit  5  has the first contact surface  55 A. The first contact surface  55 A is located at the downstream side of the seal member  42  in the first direction. A distance D 1  (see  FIG. 5 ) between the first contact surface  55 A and a downstream end  42 A of the seal member  42  in the first direction is larger than a distance D 2  (see  FIG. 9A ) between a second contact surface  69 A and an upstream end  65 A of the toner supply opening  65  in the first direction in a state where the first shutter  62  is located at the closed position. Thereby, as shown in  FIG. 3 , when the toner supply pipe  61  moves from the outside position to the inside position, and the rib  68 A of the first shutter  62  contacts the protrusion  43 A, the toner supply opening  65  is located at a farther downstream side than the seal member  42  in the first direction, that is, in the insertion space  45 . Thereby, the first shutter  62  moves from the closed position (see  FIG. 3 ) to the open position (see  FIG. 1 ) relative to the toner supply pipe  61  in a state where the toner supply opening  65  is located in the insertion space  45 . 
     As shown in  FIG. 4 , the protrusion  43 B is configured to contact a rib  68 B (see  FIG. 8B ) of the first shutter  62  described later when the toner supply pipe  61  moves from the outside position to the inside position. The protrusion  43 B is located inside the developing frame  41 . Specifically, the protrusion  43 B is located in the insertion space  45 . The protrusion  43 B is located with a space with respect to the protrusion  43 A in the axial direction. The protrusion  43 B protrudes from the inner surface of the developing frame  41  in the axial direction. The protrusion  43 B extends in the first direction. The protrusion  43 B has a downstream end E 13  and an upstream end E 14  in the first direction. The protrusion  43 B has a first contact surface  55 B at the upstream end E 14 . The first contact surface  55 B is located at the downstream side of the seal member  42  in the first direction. The distance between the first contact surface  55 B and the downstream end  42 A of the seal member  42  in the first direction is the same as the distance D 1  (see  FIG. 5 ) between the first contact surface  55 A and the downstream end  42 A of the seal member  42  in the first direction, and is larger than a distance D 3  (see  FIG. 9B ) between a second contact surface  69 B and the upstream end  65 A of the toner supply opening  65  in the first direction in a state where the first shutter  62  is located at the closed position. 
     The protrusion  43 A contacts the rib  68 A, and the protrusion  43 B contacts the rib  68 B, and thereby, the first shutter  62  moves relative to the toner supply pipe  61  in a state where the balance in the axial direction is maintained. Thereby, the first shutter  62  smoothly moves relative to the toner supply pipe  61 . 
     2.2.4 Auger Screw 
     As shown in  FIG. 5 , the auger screw  52 A is configured to convey the toner in the developing chamber  44  in the axial direction. Specifically, the auger screw  52 A is configured to convey the toner in the developing chamber  44  in a direction away from the insertion opening  46  in the axial direction. The auger screw  52 A is located in the developing chamber  44 . The auger screw  52 A extends in the axial direction. 
     The auger screw  52 B is configured to convey the toner in the developing chamber  44  in an opposite direction, in the axial direction, from the direction in which the auger screw  52 A conveys the toner in the developing chamber  44 . Specifically, the auger screw  52 B is configured to convey the toner in the developing chamber  44  toward the insertion opening  46  in the axial direction. The auger screw  52 B is located in the developing chamber  44 . The auger screw  52 B is located between the developing roller  11  and the auger screw  52 A in the mounting direction. The auger screw  52 B extends in the axial direction. 
     2.3 Toner Cartridge 
     As shown in  FIG. 7 , the toner cartridge  3  extends in the axial direction. The toner cartridge  3  has a one end E 21 , and an other end E 22  located away from the one end E 21  in the axial direction. The protruding portion  26  of the toner recovery box  18  described above is located at the one end E 21 . The protruding portion  26  protrudes from the one end E 21 . The toner cartridge  3  is located between the drum side plate  31 A (see  FIG. 4 ) and the drum side plate  31 B (see  FIG. 4 ) in a state where the toner cartridge  3  is mounted on the main unit  2 . The toner cartridge  3  is supported by the drum side plate  31 A and the drum side plate  31 B in a state where the toner cartridge  3  is mounted on the main unit  2 . The one end E 21  is located closer to the drum side plate  31 A than to the drum side plate  31 B in the axial direction in a state where the toner cartridge  3  is mounted on the main unit  2 . The one end E 21  faces the drum side plate  31 A in a state where the toner cartridge  3  is mounted on the main unit  2 . The other end E 22  is located closer to the drum side plate  31 B than to the drum side plate  31 A in the axial direction in a state where the toner cartridge  3  is mounted on the main unit  2 . The other end E 22  faces the drum side plate  31 B in a state where the toner cartridge  3  is mounted on the main unit  2 . The toner cartridge  3  includes the toner supply pipe  61 , the first shutter  62 , a cover  63 , a spring  64  (see  FIG. 8A ), the boss  72 A, and the boss  72 B. 
     2.3.1 Toner Supply Pipe 
     As shown in  FIG. 1 , the toner supply pipe  61  is configured to supply the toner to the developing chamber  44  of the developing unit  5  in a state where the toner cartridge  3  is mounted on the main unit  2 , where the toner supply pipe  61  is located at the inside position, and where the first shutter  62  is located at the open position. As shown in  FIG. 7 , the toner supply pipe  61  is located at the downstream side of the toner accommodation box  17  in the first direction. The toner supply pipe  61  has a first portion  61 A and a second portion  61 B. 
     The first portion  61 A communicates with the toner accommodation box  17 . Specifically, the first portion  61 A communicates with the toner accommodation box  17  through an opening (not shown) extending in the axial direction. The first portion  61 A extends in the axial direction. 
     The second portion  61 B continues to the first portion  61 A. The second portion  61 B communicates with the first portion  61 A. The second portion  61 B is located closer to the one end E 21  of the toner cartridge  3  than to the other end E 22  of the toner cartridge  3  in the axial direction. The second portion  61 B extends in the first direction. The second portion  61 B has an upstream end E 31  and a downstream end E 32  in the first direction. That is, the toner supply pipe  61  has the downstream end E 32  in the first direction. 
     As shown in  FIG. 8A  and  FIG. 8B , the toner supply pipe  61  has the toner supply opening  65 . The toner supply pipe  61  includes a screw  66 . 
     The toner supply opening  65  discharges the toner conveyed by the screw  66  in a state where the toner cartridge  3  is mounted on the main unit  2 , where the toner supply pipe  61  is located at the inside position, and where the first shutter  62  is located at the open position (see  FIG. 1 ). The toner supply opening  65  is provided in the second portion  61 B. The toner supply opening  65  is located closer to the downstream end E 32  of the second portion  61 B than to the upstream end E 31  of the second portion  61 B in the first direction. The toner supply opening  65  is located at the downstream side of the seal member  42  in the first direction in a state where the toner supply pipe  61  is located at the inside position (see  FIG. 1  and  FIG. 3 ). Thereby, when the first shutter  62  moves from the closed position to the open position, the toner supply opening  65  is reliably located in the developing frame  41 . 
     As shown in  FIG. 7 , the screw  66  is configured to convey the toner in the toner supply pipe  61  toward the toner supply opening  65  (see  FIG. 8A ). Specifically, the screw  66  is configured to convey the toner supplied from the toner accommodation box  17  to the first portion  61 A, toward the toner supply opening  65 . The screw  66  is located inside the toner supply pipe  61 . Specifically, the screw  66  is located inside the first portion  61 A and the second portion  61 B. The screw  66  extends in a direction in which the toner supply pipe  61  extends. The screw  66  has a spiral shape. The screw  66  does not have a shaft. Thereby, the screw  66  is located inside the toner supply pipe  61  in a state of being bent along the shape of the toner supply pipe  61 . 
     2.3.2 First Shutter 
     As shown in  FIG. 8A , the first shutter  62  is located in the outer surface of the second portion  61 B. The first shutter  62  is movable relative to the second portion  61 B between the open position and the closed position in a direction in which the second portion  61 B extends. Thereby, the first shutter  62  moves relative to the toner supply pipe  61  in a direction parallel to the first direction, when the toner cartridge  3  is mounted onto the main unit  2 . As shown in  FIG. 8B , the first shutter  62  includes a base  67 , the rib  68 A, and a rib  68 B. 
     The base  67  closes the toner supply opening  65  when the first shutter  62  is located at the closed position. The base  67  is located between the toner supply pipe  61  and the cover  63 . The base  67  has a cylindrical shape. The base  67  is movable along the outer surface of the toner supply pipe  61 . Specifically, the base  67  is movable along the outer surface of the second portion  61 B of the toner supply pipe  61 . 
     As shown in  FIG. 8B  and  FIG. 9A , the rib  68 A is configured to contact the protrusion  43 A (see  FIG. 4 ) of the developing unit  5  when the toner supply pipe  61  moves from the outside position to the inside position. The rib  68 A protrudes from the outer surface of the base  67 . Specifically, the rib  68 A protrudes from the outer surface of the base  67  in the axial direction. The rib  68 A is received in a guide groove  70 A of the cover  63  described later. The rib  68 A protrudes from the cover  63  through the guide groove  70 A in the axial direction. The rib  68 A extends in the first direction. The rib  68 A has a downstream end E 41  and an upstream end E 42  in the first direction. The rib  68 A has the second contact surface  69 A at the downstream end E 41 . That is, the first shutter  62  has the second contact surface  69 A. When the toner supply pipe  61  moves from the outside position to the inside position, the second contact surface  69 A contacts the first contact surface  55 A (see  FIG. 4 ) of the protrusion  43 A in order to move the first shutter  62  from the closed position to the open position. The second contact surface  69 A is located at the downstream side of the toner supply opening  65  in the first direction in a state where the first shutter  62  is located at the closed position. 
     As shown in  FIG. 8B  and  FIG. 9B , the rib  68 B is configured to contact the protrusion  43 B (see  FIG. 4 ) of the developing unit  5  when the toner supply pipe  61  moves from the outside position to the inside position. The rib  68 B is located at the opposite side of the rib  68 A with respect to the base  67  in the axial direction. Thereby, when the protrusion  43 A contacts the rib  68 A and the protrusion  43 B contacts the rib  68 B, the balance of the first shutter  62  in the axial direction is secured. As a result, the first shutter  62  smoothly moves relative to the toner supply pipe  61 . The rib  68 B protrudes from the outer surface of the base  67  in the axial direction. The rib  68 B is received in a guide groove  70 B of the cover  63  described later. The rib  68 B protrudes from the cover  63  through the guide groove  70 B in the axial direction. The rib  68 B extends in the first direction. The rib  68 B has a downstream end E 43  and an upstream end E 44  in the first direction. The rib  68 B has the second contact surface  69 B at the downstream end E 43 . That is, the first shutter  62  has the second contact surface  69 B. When the toner supply pipe  61  moves from the outside position to the inside position, the second contact surface  69 B contacts the first contact surface  55 B (see  FIG. 4 ) of the protrusion  43 B in order to move the first shutter  62  from the closed position to the open position. The second contact surface  69 B is located at the downstream side of the toner supply opening  65  in the first direction in a state where the first shutter  62  is located at the closed position. 
     When the toner cartridge  3  is mounted on the main unit  2 , the rib  68 A abuts the protrusion  43 A in the first direction, and the rib  68 B abuts the protrusion  43 B in the first direction, and thereby, the first shutter  62  moves from the closed position to the open position relative to the toner supply pipe  61 . The first shutter  62  moves from the open position to the closed position relative to the toner supply pipe  61  by being pressed by the spring  64  (see  FIG. 8A ) when the toner cartridge  3  is detached from the main unit  2 . 
     2.3.3 Cover 
     As shown in  FIG. 8A  and  FIG. 8B , the cover  63  covers the outer surface of the toner supply pipe  61  and the spring  64 . The cover  63  has a cylindrical shape. The cover  63  has the guide groove  70 A, a guide groove  70 B, and a cutout  71 . 
     The guide groove  70 A is configured to guide the rib  68 A when the first shutter  62  moves. The guide groove  70 A extends in the first direction. The rib  68 A is inserted in the guide groove  70 A. 
     The guide groove  70 B is configured to guide the rib  68 B when the first shutter  62  moves. The guide groove  70 B is located at the opposite side of the guide groove  70 A with respect to the toner supply pipe  61  in the axial direction. The guide groove  70 B extends in the first direction. The rib  68 B is inserted in the guide groove  70 B. 
     The cutout  71  is configured to expose the toner supply opening  65  when the first shutter  62  is located at the open position. The cutout  71  is located at the opposite side of the screw  66  with respect to the toner supply opening  65  in a radial direction of the second portion  61 B of the toner supply pipe  61 . The cutout  71  communicates with the toner supply opening  65  when the first shutter  62  is located at the open position. A part of the base  67  of the first shutter  62  is located between the cutout  71  and the toner supply opening  65  when the first shutter  62  is located at the closed position. 
     2.3.4 Spring 
     As shown in  FIG. 1 , the spring  64  presses the first shutter  62  located at the open position toward the closed position. As shown in  FIG. 8A , the spring  64  is located between the cover  63  and the toner supply pipe  61  in the radial direction of the second portion  61 B of the toner supply pipe  61 . The spring  64  contacts the first shutter  62 . The spring  64  is covered by the cover  63 . Specifically, as shown in  FIG. 1  and  FIG. 3 , in a state where the first shutter  62  is located at the open position, and in a state where the first shutter  62  is located at the closed position, the entire spring  64  is covered by the cover  63 . Thereby, the toner in the developing unit  5  is prevented from adhering to the spring  64  in a state where the toner supply pipe  61  is located at the inside position. 
     The positioning protrusion  36  (see  FIG. 1 ) in the guide  35  described above, and the positioning protrusion (not shown) in the guide  34  position the toner cartridge  3  relative to the main unit  2  against the elastic force of the spring  64 . 
     2.3.5 Boss 
     As shown in  FIG. 7 , the boss  72 A is located at the one end E 21  of the toner cartridge  3 . The boss  72 A is fitted in the guide  34  (see  FIG. 4 ) of the drum unit  4 . The boss  72 A extends in the axial direction. The boss  72 A has a cylindrical shape. 
     The boss  72 B is located at the other end E 22  of the toner cartridge  3 . The boss  72 B is fitted in the guide  35  (see  FIG. 4 ) of the drum unit  4 . The boss  72 B extends in the axial direction. The boss  72 B has a cylindrical shape. 
     3. Usage Mode of Process Unit 
     As shown in  FIG. 10 , the process unit  1  described above is mounted on the image forming apparatus  100 . The process unit  1  is detachably mounted on the image forming apparatus  100 . The toner cartridge  3  is detachably mounted on the main unit  2  in a state where the main unit  2  is mounted on the image forming apparatus  100 . 
     The image forming apparatus  100  includes a laser scan unit  101 , a transfer roller  102 , a fixing device  103 , a paper feeding section  104 , a paper feeding tray  105 , and a paper discharge tray  106 . The laser scan unit  101  is configured to expose the surface of the photosensitive drum  7 . The transfer roller  102  is configured to transfer a toner image formed in the circumferential surface of the photosensitive drum  7  onto a sheet. The transfer roller  102  contacts the circumferential surface of the photosensitive drum  7 . The fixing device  103  is configured to heat and apply pressure to the sheet having the transferred toner image to fix the toner image onto the sheet. The paper feeding section  104  is configured to feed the sheet in the sheet feeding tray  105  to between the photosensitive drum  7  and the transfer roller  102 . The paper feeding tray  105  is configured to accommodate sheets. The sheet that has passed the fixing device  103  is discharged onto the paper discharge tray  106 . 
     4. Operation and Effect 
     As shown in  FIG. 1  and  FIG. 3 , according to the process unit  1 , when the toner cartridge  3  is mounted onto the main unit  2 , the first shutter  62  moves relative to the toner supply pipe  61  from the closed position (see  FIG. 3 ) to the open position ( FIG. 1 ) in a state where the toner supply opening  65  is located inside the developing frame  41 . 
     Thus, the toner discharged from the toner supply opening  65  is prevented from staining the outer surface of the developing frame  41 . 
     As a result, the developing unit  5  is prevented from being stained when the toner cartridge  3  is mounted onto the main unit  2 . 
     5. Second Embodiment 
     A process unit of a second embodiment will be described while referring to  FIG. 11  to  FIG. 15  wherein like parts and components are designated by the same reference numerals to avoid duplicating description. 
     As shown in  FIG. 11  and  FIG. 13 , the process unit of the second embodiment includes a main unit  200 A and a toner cartridge  200 B. 
     5.1 Developing Unit 
     As shown in  FIG. 11 , the insertion space  45  and the insertion opening  46  of the main unit  200 A are located closer to the drum side plate  31 B than to the drum side plate  31 A in the axial direction. As shown in  FIG. 12 , the developing unit  5  includes a seal member  202 , a second shutter  203 , and a protrusion  212 . 
     5.1.1 Seal Member 
     In a state where a toner supply pipe  204  (see  FIG. 14  and  FIG. 15 ) is located at the inside position, the seal member  202  seals between the developing frame  41  and the toner supply pipe  204 . The seal member  202  is located in the insertion opening  46 . The seal member  202  extends in a direction intersecting the first direction. Preferably, the seal member  202  extends in a direction perpendicular to the first direction. The seal member  202  has elasticity. Specifically, the seal member  202  includes the seal layer  53  described above, and the support layer  54  described above. The seal member  202  has an opening  201 . 
     When the toner supply pipe  204  is located at the inside position, the toner supply pipe  204  is inserted in the opening  201 . The opening  201  is located at the center portion of the seal member  202 . The diameter of the opening  201  is smaller than the diameter of the toner supply pipe  204 . 
     As shown in  FIG. 14  and  FIG. 15 , in a state where the toner supply pipe  204  is located at the inside position, the seal member  202  deforms so that the opening  201  (see  FIG. 12 ) expands by being pressed by the toner supply pipe  204 . The seal member  202  contacts the circumferential surface of the toner supply pipe  204  in a state where the toner supply pipe  204  is located at the inside position. Thereby, the seal member  202  seals between the developing frame  41  and the toner supply pipe  204 . 
     5.1.2 Second Shutter 
     As shown in  FIG. 12 , the second shutter  203  is movable relative to the developing frame  41  between an open position (see  FIG. 15 ) at which the insertion opening  46  is opened and a closed position (see  FIG. 12 ) at which the insertion opening  46  is closed. The second shutter  203  is located at the downstream side of the seal member  202  in the first direction. The second shutter  203  is located in the insertion space  45 . The second shutter  203  is pressed toward the closed position by a coil spring  203 A. 
     5.1.3 Protrusion 
     As shown in  FIG. 14 , the protrusion  212  is configured to contact a first shutter  205  described later, when the toner supply pipe  204  moves from the outside position to the inside position. As shown in  FIG. 12 , the protrusion  212  is located inside the developing frame  41 , and protrudes from the developing frame  41 . Specifically, the protrusion  212  is located in the insertion space  45 . The protrusion  212  protrudes from the inner surface  45 A of the developing frame  41 . The protrusion  212  extends in the first direction. The protrusion  212  has a downstream end E 51  and an upstream end E 52  in the first direction. The protrusion  212  has a first contact surface  212 A at the upstream end E 52 . That is, the developing unit  5  has the first contact surface  212 A. The first contact surface  212 A is located at the downstream side of the seal member  202  in the first direction. A distance D 11  between the first contact surface  212 A and a downstream end  202 A of the seal member  202  in the first direction is larger than a distance D 12  (see  FIG. 14 ) between a second contact surface  205 A and an upstream end  208 A of a toner supply opening  208  in the first direction in a state where the first shutter  205  is located at the closed position. Thereby, as shown in  FIG. 14 , when the toner supply pipe  204  moves from the outside position to the inside position, and the first shutter  205  contacts the protrusion  212 , the toner supply opening  208  is located at a farther downstream side than the seal member  202  in the first direction, that is, in the insertion space  45 . Thereby, the first shutter  205  moves from the closed position (see  FIG. 14 ) to the open position (see  FIG. 15 ) relative to the toner supply pipe  204  in a state where the toner supply opening  208  is located in the insertion space  45 . 
     5.2 Toner Cartridge 
     As shown in  FIG. 13 , the toner cartridge  200 B includes the toner supply pipe  204 , the first shutter  205 , a flexible screw  206 , a toner conveyance pipe  207 , an auger screw  210 , a first bevel gear  213 , a second bevel gear  214 , an idle gear  215 , and a screw gear  216  (see  FIG. 14 ). 
     5.2.1 Toner Supply Pipe 
     The toner supply pipe  204  is configured to supply the toner to the developing chamber  44  of the developing unit  5  in a state (see  FIG. 15 ) where the toner cartridge  200 B is mounted on the main unit  200 A, where the toner supply pipe  204  is located at the inside position, and where the first shutter  205  is located at the open position. The toner supply pipe  204  is located at the downstream side of the toner accommodation box  17  in the first direction. The toner supply pipe  204  is located closer to the other end E 22  of the toner cartridge  200 B than to the one end E 21  of the toner cartridge  200 B in the axial direction. The toner supply pipe  204  extends in the first direction. The toner supply pipe  204  has an upstream end E 61  and a downstream end E 62  in the first direction. The toner supply pipe  204  has the toner supply opening  208  and an opening  209 . 
     The toner supply opening  208  discharges the toner discharged from an opening  211  of the first shutter  205  in a state where the toner cartridge  200 B is mounted on the main unit  200 A, where the toner supply pipe  204  is located at the inside position, and where the first shutter  205  is located at the open position. The toner supply opening  208  is located closer to the downstream end E 62  than to the upstream end E 61  in the first direction. The toner supply opening  208  is located at the downstream side of the seal member  202  in the first direction in a state where the toner supply pipe  204  is located at the inside position (see  FIG. 14  and  FIG. 15 ). 
     The protrusion  212  is inserted in the opening  209  in a state where the toner cartridge  200 B is mounted on the main unit  200 A, where the toner supply pipe  204  is located at the inside position, and where the first shutter  205  is located at the open position. The opening  209  is located at the downstream end E 62  of the toner supply pipe  204 . 
     5.2.2 First Shutter 
     As shown in  FIG. 14  and  FIG. 15 , the first shutter  205  is movable relative to the toner supply pipe  204  between an open position (see  FIG. 15 ) at which the toner supply opening  208  is opened and a closed position (see  FIG. 14 ) at which the toner supply opening  208  is closed. The first shutter  205  is located inside the toner supply pipe  204 . The first shutter  205  has the opening  211  and the second contact surface  205 A. 
     The opening  211  discharges the toner conveyed by the flexible screw  206  in a state where the toner cartridge  200 B is mounted on the main unit  200 A, where the toner supply pipe  204  is located at the inside position, and where the first shutter  205  is located at the open position. The opening  211  communicates with the toner supply opening  208  in a state where the first shutter  205  is located at the open position (see  FIG. 15 ). Communication of the opening  211  with the toner supply opening  208  is blocked in a state where the first shutter  205  is located at the closed position (see  FIG. 14 ). 
     When the toner supply pipe  204  moves from the outside position to the inside position, the second contact surface  205 A contacts the first contact surface  212 A (see  FIG. 12 ) of the protrusion  212  in order to move the first shutter  205  from the closed position to the open position. The second contact surface  205 A is located at the downstream side of the toner supply opening  208  in the first direction in a state where the first shutter  205  is located at the closed position. Specifically, the second contact surface  205 A is located at the downstream end of the first shutter  205  in the first direction. The second contact surface  205 A extends in a direction intersecting the first direction. Preferably, the second contact surface  205 A extends in a direction perpendicular to the first direction. 
     When the toner cartridge  200 B is mounted on the main unit  200 A, the first shutter  205  abuts the protrusion  212  in the first direction, thereby moving from the closed position to the open position relative to the toner supply pipe  204 . The first shutter  205  located at the open position is pressed toward the closed position by the elastic force of the flexible screw  206 . Thereby, when the toner cartridge  200 B is detached from the main unit  200 A, the first shutter  205  moves from the open position to the closed position relative to the toner supply pipe  204 . 
     5.2.3 Flexible Screw 
     As shown in  FIG. 15 , the flexible screw  206  is configured to convey the toner inside the toner supply pipe  204  in the first direction. The flexible screw  206  is configured to convey the toner inside the toner supply pipe  204  toward the toner supply opening  208 . The flexible screw  206  is arranged inside the toner supply pipe  204 . The flexible screw  206  extends in a direction in which the toner supply pipe  204  extends. The flexible screw  206  has a spiral shape. The flexible screw  206  does not have a shaft. Thereby, the flexible screw  206  elastically deforms in the direction in which the toner supply pipe  204  extends. In other words, the flexible screw  206  elastically deforms in the first direction. The flexible screw  206  is configured to press the first shutter  205  located at the open position toward the closed position. 
     5.2.4 Toner Conveyance Pipe 
     As shown in  FIG. 13 , the toner conveyance pipe  207  is located at the downstream side of the toner accommodation box  17  in the first direction. The toner conveyance pipe  207  communicates with the toner accommodation box  17 . Specifically, the toner conveyance pipe  207  communicates with the toner accommodation box  17  through an opening (not shown) extending in the axial direction. The toner conveyance pipe  207  extends in the axial direction. The toner conveyance pipe  207  communicates with the upstream end E 61  of the toner supply pipe  204 . 
     5.2.5 Auger Screw 
     As shown in  FIG. 13 , the auger screw  210  is configured to convey the toner in the toner conveyance pipe  207  toward the toner supply pipe  204 . The auger screw  210  is located in the toner supply pipe  207 . The auger screw  210  extends in the axial direction. 
     5.2.6 First Bevel Gear, Second Bevel Gear, Idle Gear, and Screw Gear 
     The first bevel gear  213 , the second bevel gear  214 , the idle gear  215 , and the screw gear  216  (see  FIG. 14 ) constitute a gear array for transmitting driving from the auger screw  210  to the flexible screw  206 . The first bevel gear  213  rotates together with the auger screw  210 . The first bevel gear  213  is attached to an end portion of the auger screw  210 . The second bevel gear  214  engages the first bevel gear  213 . The idle gear  215  rotates together with the second bevel gear  214 . The idle gear  215  is a spur gear. As shown in  FIG. 14 , the screw gear  216  rotates together with the flexible screw  206 . The screw gear  216  is attached to an end portion of the flexible screw  206 . The screw gear  216  is a spur gear. The screw gear  216  engages the idle gear  215 . 
     5.3 Operation and Effect of Second Embodiment 
     As shown in  FIG. 14  and  FIG. 15 , in the process unit of the second embodiment, when the toner cartridge  200 B is mounted onto the main unit  200 A, the first shutter  205  moves from the closed position to the open position in a state where the toner supply opening  208  is located inside the developing frame  41 . 
     Thus, the toner discharged from the toner supply opening  208  is prevented from staining the outer surface of the developing frame  41 . 
     This suppresses staining of the developing unit  5  when the toner cartridge  200 B is mounted onto the main unit  200 A. 
     6. Modification 
     While the disclosure has been described in detail with reference to the above aspects thereof, it would be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the claims. 
     For example, the process unit  1  need not be detachably mounted on the image forming apparatus  100 . In this case, the main unit  2  may be provided in the image forming apparatus  100 , and the toner cartridge  3  may be detachably mounted on the main unit  2  provided in the image forming apparatus  100 . 
     Further, the first contact surface that contacts the first shutter may be located outside the developing frame  41 . For example, the outer surface of the developing frame  41  may be the first contact surface. When the toner cartridge  3  is mounted onto the main unit  2 , the first shutter may contact the outer surface of the developing frame  41  (the first contact surface) in a state where the toner supply opening  65  is located inside the developing frame  41 , thereby moving from the closed position to the open position, with respect to the toner supply pipe  61 .