JP7501251B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming device.

Conventionally, an image forming apparatus includes a main body housing, a process cartridge, and a transfer device. The process cartridge includes a photosensitive drum and a developing device. The transfer device is located above the photosensitive drum when the process cartridge is attached to the main body housing. The developing device includes a developing housing, a developing roller, and an agitator. The developing housing has a developing chamber in which the developing roller is disposed, and a toner storage chamber in which toner is stored. When the process cartridge is attached to the main body housing, the toner storage chamber is located below the developing chamber. The agitator is located within the toner storage chamber, and transports toner from the toner storage chamber to the developing chamber (see Patent Document 1 below).

JP 2008-170951 A

In an image forming device such as that described in Patent Document 1, when the amount of toner remaining in the toner storage chamber becomes low, the entire process cartridge including the photosensitive drum must be replaced even if there is no need to replace the photosensitive drum. This makes it difficult to reduce the operating costs of such an image forming device.

The objective of this disclosure is to provide an image forming device in which the toner cartridge and drum cartridge can be replaced separately in a configuration in which the transfer device is positioned above the photosensitive drum while the drum cartridge is attached to the main body housing.

(1) The image forming device disclosed herein includes a main body housing, a drum cartridge, a toner cartridge, and a transfer device.

The drum cartridge can be attached to the main body housing. The drum cartridge includes a photosensitive drum and a developing device. The photosensitive drum can rotate about an axis. The axis of the photosensitive drum extends in a first direction. The developing device has a developing roller and a developing housing. The developing housing supports the developing roller.

The toner cartridge can contain toner to be supplied to the developing housing. The toner cartridge can be attached to the drum cartridge.

The transfer device transfers the toner on the photosensitive drum to a sheet. The transfer device is located above the photosensitive drum when the drum cartridge is installed in the main body housing.

The developing housing has a first developing unit, a second developing unit, and a wall. The first developing unit supports the developing roller. When the toner cartridge is attached to the drum cartridge, the second developing unit is located above the toner cartridge. The second developing unit is located on the opposite side of the photosensitive drum from the first developing unit. The second developing unit has a toner receiving port. The second developing unit communicates with the first developing unit. The wall is located between the first developing unit and the second developing unit. The wall has a first opening. The first opening communicates with the first developing unit and the second developing unit.

The developing device further includes a developing shutter. The developing shutter is movable between a developing closed position and a developing open position. When the developing shutter is in the developing closed position, the developing shutter closes the toner receiving opening. When the developing shutter is in the developing open position, the toner receiving opening is open.

The toner cartridge includes a cartridge housing, a toner shutter, and an agitator. The cartridge housing is capable of containing toner. The cartridge housing has a toner discharge port. The toner shutter is movable between a toner closed position and a toner open position. When the toner shutter is in the toner closed position, the toner shutter closes the toner discharge port. When the toner shutter is in the toner open position, the toner discharge port opens. The agitator is located within the cartridge housing. The agitator is rotatable. The agitator includes a shaft and a blade. The blade is rotatable together with the shaft. The blade has a first end and a second end. The first end of the blade is fixed to the shaft. The second end of the blade is located away from the first end.

When the toner cartridge is attached to the drum cartridge, the developer shutter is in the developer open position, and the toner shutter is in the toner open position, the toner discharge port communicates with the toner receiving port.

When the toner cartridge is attached to the drum cartridge, the developer shutter is in the developer open position, and the toner shutter is in the toner open position, when the agitator rotates, the second end of the blade reaches the height of the first opening in the vertical direction.

With this configuration, even if the toner cartridge is attached to the drum cartridge and the drum cartridge is attached to the main body housing, and the cartridge housing of the toner cartridge is positioned below the second developing unit, the agitator can stably supply toner from the cartridge housing to the first developing unit through the second developing unit and the first opening.

In addition, by removing the toner cartridge from the drum cartridge with the development shutter in the development closed position and the toner shutter in the toner closed position, toner leakage from the toner cartridge and drum cartridge can be prevented.

As a result, in a configuration in which the transfer device is positioned above the photosensitive drum with the drum cartridge attached to the main body housing, the drum cartridge and toner cartridge can be replaced separately and smoothly.

(2) When the toner shutter moves from the toner open position to the toner closed position, the toner shutter may move in a direction opposite to the direction of rotation of the agitator.

When the second end of the agitator blade reaches the height of the first opening in the vertical direction and the agitator stops rotating, if the toner shutter moves in the same direction as the agitator rotation and moves from the toner open position to the toner closed position, there is a risk that the blade will be pinched between the toner shutter and the cartridge housing. In this case, it will be difficult to move the toner shutter from the toner open position to the toner closed position.

On the other hand, according to the above configuration, when the toner shutter moves from the toner open position to the toner closed position, the toner shutter moves in the direction opposite to the rotation direction of the agitator. Therefore, when the toner shutter moves from the toner open position to the toner closed position with the second end of the agitator blade reaching the height of the first opening in the vertical direction, the blade is pushed by the toner shutter and moves inside the toner discharge port while bending. As a result, it is possible to prevent the blade from being pinched between the toner shutter and the cartridge housing, and the toner shutter can be stably moved from the toner open position to the toner closed position.

(3) When the developer shutter moves from the developer open position to the developer closed position, the developer shutter may move in a direction opposite to the rotation direction of the agitator.

This configuration prevents the agitator blades from becoming pinched between the development shutter and the development housing, allowing the development shutter to be moved stably from the development open position to the development closed position.

(4) The developing device may further include a supply roller and a toner transport member. The supply roller supplies toner to the developing roller. The supply roller is supported by the first developing unit. The toner transport member is capable of transporting toner in the first direction. The toner transport member is disposed between the supply roller and the wall.

According to this configuration, the toner transport member can transport the toner supplied from the cartridge housing to the first developing unit in the first direction and supply it to the supply roller. Therefore, even if the dimensions of the first opening, the toner receiving port and/or the toner discharge port in the first direction are reduced, the toner can be appropriately supplied to the supply roller. Furthermore, reducing the dimension of the toner receiving port in the first direction can prevent toner from leaking from the developing device. Furthermore, reducing the dimension of the toner discharge port in the first direction can prevent toner from leaking from the toner cartridge.

(5) The blade may have a height that overlaps with the toner transport member in the vertical direction when the second end reaches the height of the first opening.

With this configuration, the agitator can stably supply toner from the cartridge housing to the toner transport member.

(6) The developing housing may have a second opening and a toner return port. The second opening is located away from the first opening in the first direction. The second opening communicates with the first developing unit. The toner return port is located away from the toner receiving port in the first direction. The toner return port communicates with the second opening. The cartridge housing has a toner receiving port. The toner receiving port is located away from the toner discharge port in the first direction. When the toner cartridge is attached to the drum cartridge, the developing shutter is located in the developing open position, and the toner shutter is located in the toner open position, the toner receiving port communicates with the toner return port.

With this configuration, when the toner cartridge is attached to the drum cartridge, the development shutter is in the development open position, and the toner shutter is in the toner open position, the toner can be returned from the first development unit to the cartridge housing through the second opening, the toner return port, and the toner receiving port. Therefore, the toner can be circulated between the first development unit and the cartridge housing. As a result, the deterioration of the toner can be prevented from affecting image formation.

(7) The cartridge housing may have a cylindrical shape extending in the first direction. The axis of rotation of the shaft may coincide with the axis of the cartridge housing.

With this configuration, when the toner cartridge is attached to the drum cartridge, the development shutter is in the development open position, and the toner shutter is in the toner open position, and the agitator rotates, the agitator can smoothly transport the toner contained in the cartridge housing to the first development unit. Also, the toner shutter can be smoothly moved along the cartridge housing between the toner closed position and the toner open position.

(8) The toner shutter may have a handle.

With this configuration, the user can hold the handle and move the toner shutter between the toner closed position and the toner open position.

(9) The toner shutter may have a first protrusion. The developer shutter has a first hole. When the toner cartridge is attached to the drum cartridge, the first protrusion fits into the first hole.

(10) The toner cartridge may be detachably attached to the drum cartridge along a first direction. The first protrusion may be located at one end of the toner shutter in the first direction. The toner shutter may have a second protrusion. The second protrusion is located at the other end of the toner shutter in the first direction. The developer shutter has a second hole. When the toner cartridge is attached to the drum cartridge, the second protrusion fits into the second hole.

With this configuration, the development shutter can be moved together with the toner shutter while the toner cartridge is attached to the drum cartridge.

(11) The cartridge housing may have a third protrusion. The drum cartridge may have a third hole. When the toner cartridge is attached to the drum cartridge, the third protrusion fits into the third hole.

With this configuration, when the toner cartridge is attached to the drum cartridge, the cartridge housing is fixed to the drum cartridge. Therefore, when the toner cartridge is attached to the drum cartridge, the toner shutter can be moved stably relative to the cartridge housing, and the toner shutter can be moved smoothly between the toner closed position and the toner open position.

According to the image forming device disclosed herein, in a configuration in which the drum cartridge is attached to the main body housing and the transfer device is positioned above the photosensitive drum, the toner cartridge and drum cartridge can be replaced separately and smoothly.

FIG. 1 is a schematic diagram of an image forming apparatus. FIG. 2 is an enlarged view of the drum cartridge shown in FIG. 1, showing a state in which the toner cartridge is mounted in the drum cartridge, the developer shutter is located at the developer open position, and the toner shutter is located at the toner open position. FIG. 3 is an enlarged view of the drum cartridge shown in FIG. 1, showing a state in which the toner cartridge is mounted in the drum cartridge, the development shutter is located at the development closed position, and the toner shutter is located at the toner closed position. FIG. 4 is a front view of the drum cartridge shown in FIG. FIG. 5 is a cross-sectional view of the drum cartridge shown in FIG. FIG. 6 is a front view of the developing device shown in FIG. 7 is a cross-sectional view of the developing device shown in FIG. 8 is a cross-sectional view of the developing device shown in FIG. FIG. 9 is a side view of the drum cartridge shown in FIG. 1, showing a state in which the toner cartridge is mounted in the drum cartridge, the developer shutter is in the developer open position, and the toner shutter is in the toner open position. FIG. 10 is a cross-sectional view taken along the line AA of the drum cartridge shown in FIG. 5, showing a state in which the toner cartridge is mounted in the drum cartridge, the developer shutter is in the developer open position, and the toner shutter is in the toner open position. FIG. 11 is a cross-sectional view taken along the line AA of the drum cartridge shown in FIG. 5, showing a state in which the toner cartridge is mounted in the drum cartridge, the development shutter is located at the development closed position, and the toner shutter is located at the toner closed position. FIG. 12 is a perspective view of the toner cartridge shown in FIG. FIG. 13 is a schematic diagram of the toner cartridge shown in FIG.

1. Image forming apparatus 1
An image forming apparatus 1 will be described with reference to FIGS.

As shown in FIG. 1, the image forming device 1 includes a main body 2, a sheet cassette 3, four drum cartridges 4Y, 4M, 4C, and 4K, four toner cartridges 5Y, 5M, 5C, and 5K, an exposure device 6, a transfer device 7, and a fixing device 8.

1.1 Main body housing 2
The main body housing 2 accommodates a sheet cassette 3, four drum cartridges 4Y, 4M, 4C, and 4K, four toner cartridges 5Y, 5M, 5C, and 5K, an exposure device 6, a transfer device 7, and a fixing device 8.

1.2 Sheet Cassette 3
The sheet cassette 3 is capable of containing sheets S. The sheets S in the sheet cassette 3 are transported toward a secondary transfer roller 73. The secondary transfer roller 73 will be described later.

1.3 Four drum cartridges 4Y, 4M, 4C, and 4K
The four drum cartridges 4Y, 4M, 4C, and 4K can be attached to the main body housing 2. More specifically, each of the four drum cartridges 4Y, 4M, 4C, and 4K can be attached to and detached from the main body housing 2 along a first direction. The first direction is the direction in which the drum shaft 411 of the photosensitive drum 41K extends. The photosensitive drum 41K will be described later. When the four drum cartridges 4Y, 4M, 4C, and 4K are attached to the main body housing 2, the four drum cartridges 4Y, 4M, 4C, and 4K are positioned at intervals from one another in the second direction. The second direction intersects with the first direction.

The four drum cartridges 4Y, 4M, 4C, and 4K have the same configuration. Therefore, in the following, we will explain drum cartridge 4K in detail and omit the explanation of drum cartridges 4Y, 4M, and 4C.

1.3.1 4K drum cartridge
As shown in FIG. 2, the drum cartridge 4K includes a photosensitive drum 41K, a charging device 46K, and a developing device 43K.

The photosensitive drum 41K extends in a first direction. The photosensitive drum 41K has a cylindrical shape. The photosensitive drum 41K is rotatable about a drum shaft 411. The drum shaft 411 extends in the first direction.

The charging device 46K charges the peripheral surface of the photosensitive drum 41K. Specifically, the charging device 46K is a charging roller. The charging device 46K may also be a scorotron type charger.

The developing device 43K is capable of supplying toner to the photosensitive drum 41K. The developing device 43K has a developing roller 431K.

The developing roller 431K can supply toner to the photosensitive drum 41K. The developing roller 431K extends in a first direction. The developing roller 431K can rotate about a developing shaft 4311. The developing shaft 4311 extends in the first direction. In this embodiment, the developing roller 431K contacts the photosensitive drum 41K. The developing roller 431K may be spaced a predetermined distance from the photosensitive drum 41K.

1.3.2 Drum Cartridges 4Y, 4M, 4C
As shown in Fig. 1, the drum cartridge 4Y includes a photosensitive drum 41Y, a charging device 46Y, and a developing device 43Y. The developing device 43Y has a developing roller 431Y. The drum cartridge 4M includes a photosensitive drum 41M, a charging device 46M, and a developing device 43M. The developing device 43M has a developing roller 431M. The drum cartridge 4C includes a photosensitive drum 41C, a charging device 46C, and a developing device 43C. The developing device 43C has a developing roller 431C.

1.4 Four toner cartridges 5Y, 5M, 5C, and 5K
The toner cartridge 5Y is mountable to the developing device 43Y of the drum cartridge 4Y. The toner cartridge 5Y is capable of containing toner to be supplied to the developing device 43Y. The toner cartridge 5M is mountable to the developing device 43M of the drum cartridge 4M. The toner cartridge 5M is capable of containing toner to be supplied to the developing device 43M. The toner cartridge 5C is mountable to the developing device 43C of the drum cartridge 4C. The toner cartridge 5C is capable of containing toner to be supplied to the developing device 43C. The toner cartridge 5K is mountable to the developing device 43K of the drum cartridge 4K. The toner cartridge 5K is capable of containing toner to be supplied to the developing device 43K.

1.5 Exposure device 6
The exposure device 6 can expose the surfaces of the four photosensitive drums 41Y, 41M, 41C, and 41K. The exposure device 6 emits light that exposes the charged surfaces of the photosensitive drums 41Y, 41M, 41C, and 41K. As a result, electrostatic latent images are formed on the surfaces of the photosensitive drums 41Y, 41M, 41C, and 41K. Toner is supplied to the electrostatic latent images.

When the four drum cartridges 4Y, 4M, 4C, and 4K are attached to the main body housing 2, the exposure device 6 is located below the four drum cartridges 4Y, 4M, 4C, and 4K. Note that below means below in the vertical direction when the image forming device 1 is placed in its normal use state.

Specifically, the exposure device 6 is a laser scanning unit. The exposure device 6 may also be an LED array.

1.6 Transfer device 7
The transfer device 7 transfers the toner on the four photosensitive drums 41Y, 41M, 41C, and 41K to a sheet. When the four drum cartridges 4Y, 4M, 4C, and 4K are mounted in the main body housing 2, the transfer device 7 is located on the opposite side of the exposure device 6 with respect to the four drum cartridges 4Y, 4M, 4C, and 4K. When the four drum cartridges 4Y, 4M, 4C, and 4K are mounted in the main body housing 2, the transfer device 7 is located above the four photosensitive drums 41Y, 41M, 41C, and 41K. The transfer device 7 includes an intermediate transfer belt 71, four primary transfer rollers 72Y, 72M, 72C, and 72K, and a secondary transfer roller 73.

When the four drum cartridges 4Y, 4M, 4C, and 4K are mounted in the main body housing 2, the four photosensitive drums 41Y, 41M, 41C, and 41K come into contact with the intermediate transfer belt 71. When the four drum cartridges 4Y, 4M, 4C, and 4K are mounted in the main body housing 2, the intermediate transfer belt 71 passes between the photosensitive drum 41Y and the primary transfer roller 72Y, between the photosensitive drum 41M and the primary transfer roller 72M, between the photosensitive drum 41C and the primary transfer roller 72C, and between the photosensitive drum 41K and the primary transfer roller 72K.

The primary transfer roller 72Y transfers the toner on the photosensitive drum 41Y to the intermediate transfer belt 71. The primary transfer roller 72M transfers the toner on the photosensitive drum 41M to the intermediate transfer belt 71. The primary transfer roller 72C transfers the toner on the photosensitive drum 41C to the intermediate transfer belt 71. The primary transfer roller 72K transfers the toner on the photosensitive drum 41K to the intermediate transfer belt 71.

The secondary transfer roller 73 is aligned with the intermediate transfer belt 71 in the second direction. The secondary transfer roller 73 contacts the intermediate transfer belt 71. The sheet S transported from the sheet cassette 3 passes between the intermediate transfer belt 71 and the secondary transfer roller 73. At this time, the secondary transfer roller 73 transfers the toner transferred to the intermediate transfer belt 71 onto the sheet S.

1.7 Fixing device 8
The fixing device 8 applies heat and pressure to the sheet S onto which the toner has been transferred, thereby fixing the toner to the sheet S. The sheet that has passed through the fixing device 8 is discharged onto the top surface of the main body housing 2.

2. Details of the Drum Cartridge 4K Next, the drum cartridge 4K will be described in detail with reference to FIGS.

As shown in FIG. 2, the drum cartridge 4K includes the above-mentioned photosensitive drum 41K, the above-mentioned charging device 46K, and the above-mentioned developing device 43K, as well as a drum frame 42K, a drum cleaner 47K, a waste toner tube 49K (see FIG. 4), a waste toner transport member 48K (see FIG. 5), and a cushion member 9K (see FIG. 5). In other words, the image forming device 1 includes a cushion member 9K.

2.1 Drum frame 42K
The drum frame 42K supports the photosensitive drum 41K, the charging device 46K, the developing device 43K, the drum cleaner 47K, and the waste toner pipe 49K. As shown in Fig. 4, the drum frame 42K includes a first side frame 421, a second side frame 422, and a flange 423. In other words, the drum cartridge 4K includes the first side frame 421, the second side frame 422, and the flange 423.

2.1.1 First side frame 421 and second side frame 422
The first side frame 421 supports one end of the photosensitive drum 41 in the first direction. The second side frame 422 is spaced apart from the first side frame 421 in the first direction. The second side frame 422 supports the other end of the photosensitive drum 41 in the first direction.

As shown in FIG. 5, the first side frame 421 extends in the second direction. The first side frame 421 has a first oblong hole 4211, a second oblong hole 4212, and a hole 4213.

The first long hole 4211 is located at the center of the first side frame 421 in the second direction. The first long hole 4211 extends in the direction in which the photosensitive drum 41K and the developing roller 431K face each other. The first long hole 4211 is fitted with the first developing protrusion 435A of the developing device 43K. The first developing protrusion 435A will be described later.

The second oblong hole 4212 is located on the opposite side of the photosensitive drum 41K from the first oblong hole 4211 in the second direction. The direction in which the second oblong hole 4212 extends is parallel to the direction in which the first oblong hole 4211 extends. The second oblong hole 4212 is fitted with a second developing protrusion 436A of the developing device 43K. The second developing protrusion 436A will be described later.

The hole 4213 is located on the opposite side of the photosensitive drum 41K from the first long hole 4211 in the second direction. The hole 4213 communicates with the internal space of the cleaner housing 472 of the drum cleaner 47K. The cleaner housing 472 will be described later.

As shown in FIG. 4, the second side frame 422 is described similarly to the first side frame 421, except that it does not have a hole 4213. Therefore, the description of the second side frame 422 is omitted.

2.1.2 Flange 423
The flange 423 is located on the opposite side of the second side frame 422 with respect to the first side frame 421 in the first direction. The flange 423 extends in the first direction from the first side frame 421. As shown in Fig. 5, the flange 423 is located away from the hole 4213 in the second direction. The flange 423 has a hole 4231.

2.2 Drum Cleaner 47K
As shown in Fig. 2, the drum cleaner 47K cleans the peripheral surface of the photosensitive drum 41K. The drum cleaner 47K is located between the first side frame 421 and the second side frame 422 in the first direction (see Fig. 4). The drum cleaner 47K is located on the opposite side of the photosensitive drum 41K to the developing roller 431K. The drum cleaner 47K includes a cleaning blade 471, a cleaner housing 472, and a screw auger 473.

The edge of the cleaning blade 471 comes into contact with the surface of the photosensitive drum 41K. When the photosensitive drum 41K rotates, the cleaning blade 471 scrapes off the toner remaining on the surface of the photosensitive drum 41K as waste toner.

The cleaner housing 472 contains waste toner. The cleaner housing 472 supports the cleaning blade 471. The cleaner housing 472 has an opening 4721. The opening 4721 receives the waste toner scraped off by the cleaning blade 471. The cleaner housing 472 extends in a first direction. One end of the cleaner housing 472 in the first direction is connected to the first side frame 421 (see FIG. 4). The other end of the cleaner housing 472 in the first direction is connected to the second side frame 422 (see FIG. 4). The internal space of the cleaner housing 472 communicates with a hole 4213 in the first side frame 421 (see FIG. 5).

The screw auger 473 is located within the cleaner housing 472. The screw auger 473 extends in a first direction. The screw auger 473 transports waste toner within the cleaner housing 472 in the first direction toward the hole 4213.

2.3 Waste toner tube 49K
As shown in FIGS. 4 and 5, the waste toner pipe 49K allows the waste toner from the drum cleaner 47K to pass through. The waste toner pipe 49K is located on the opposite side of the second side frame 422 with respect to the first side frame 421. The waste toner pipe 49K has a first end 491 and a second end 492. The first end 491 of the waste toner pipe 49K is connected to the first side frame 421. The internal space of the first end 491 communicates with a hole 4213 of the first side frame 421. As a result, the first end 491 of the waste toner pipe 49K communicates with the cleaner housing 472 of the drum cleaner 47K. The second end 492 of the waste toner pipe 49K is located away from the first end 491. The second end 492 is connected to the flange 423. The internal space of the second end 492 communicates with a hole 4231 of the flange 423.

As shown in FIG. 5, when the drum cartridge 4K is attached to the main body housing 2, the second end 492 of the waste toner tube 49K is located lower than the first end 491 of the waste toner tube 49K. When the drum cartridge 4K is attached to the main body housing 2, the waste toner tube 49K slopes downward from the first end 491 to the second end 492. This allows the waste toner to be sent from the first end 491 to the second end 492 by utilizing gravity.

2.4 Waste toner transport member 48K
The waste toner transport member 48K transports the waste toner. More specifically, the waste toner transport member 48K transports the waste toner in the waste toner tube 49K from the first end 491 to the second end 492. The waste toner transport member 48K is located inside the waste toner tube 49K. The waste toner transport member 48K is flexible. The waste toner transport member 48K is a spring auger.

2.5 Developing device 43K
As shown in FIG. 2, the developing device 43K includes, in addition to the developing roller 431K described above, a developing housing 432K, a supply roller 433K, a toner transport member 434K, a developing shutter 44K, two first developing projections 435A, 435B (see FIG. 6), and two second developing projections 436A, 436B (see FIG. 6).

2.5.1 Developer unit 432K
The developing housing 432K has a first developing section 4321, a wall 4324, a second developing section 4322, and a cartridge mounting section 4325.

2.5.1.1 First Development Unit 4321
The first developing unit 4321 of the developing housing 432K supports the developing roller 431K. The first developing unit 4321 accommodates the developing roller 431K, a supply roller 433K, and a toner transport member 434K.

As shown in Figures 2 and 6, the first developing unit 4321 has a first side wall 43211, a second side wall 43212, a bottom wall 43213, and an upper wall 43214.

As shown in FIG. 6, the first side wall 43211 supports one end of the developing roller 431K in the first direction. The second side wall 43212 is separated from the first side wall 43211 in the first direction. The second side wall 43212 supports the other end of the developing roller 431K in the first direction.

When the drum cartridge 4K is attached to the main body housing 2, the bottom wall 43213 is located below the developing roller 431K. The bottom wall 43213 is located between the first side wall 43211 and the second side wall 43212 in the first direction. One end of the bottom wall 43213 in the first direction is connected to the first side wall 43211. The other end of the bottom wall 43213 in the first direction is connected to the second side wall 43212.

The upper wall 43214 is located on the opposite side of the bottom wall 43213 with respect to the developing roller 431K. The upper wall 43214 is located between the first side wall 43211 and the second side wall 43212 in the first direction. One end of the upper wall 43214 in the first direction is connected to the first side wall 43211. The other end of the upper wall 43214 in the first direction is connected to the second side wall 43212.

As shown in FIG. 2, the wall 4324 is located on the opposite side of the photosensitive drum 41K from the first developing unit 4321. The wall 4324 extends in a first direction. One end of the wall 4324 in the first direction is connected to the first side wall 43211. The other end of the wall 4324 in the first direction is connected to the second side wall 43212.

As shown in FIG. 7, the wall 4324 has an arc shape. When the drum cartridge 4K is attached to the main housing 2, the wall 4324 has an upper end and a lower end in the vertical direction. When the drum cartridge 4K is attached to the main housing 2, the upper end of the wall 4324 is connected to the upper wall 43214. When the drum cartridge 4K is attached to the main housing 2, the lower end of the wall 4324 is connected to the bottom wall 43213.

As shown in Figures 2 and 8, the wall 4324 has a first opening 43241 (see Figure 2) and a second opening 43242 (see Figure 8). In other words, the developing housing 432 has a first opening 43241 and a second opening 43242.

As shown in FIG. 2, the first opening 43241 communicates with the first developing section 4321. The first opening 43241 is located at the center of the wall 4324 in the first direction.

As shown in FIG. 8, the second opening 43242 communicates with the first developing section 4321. The second opening 43242 is located away from the first opening 43241 in the first direction. The second opening 43242 is located between the first opening 43241 and the second side wall 43212 in the first direction.

Although not shown, the wall 4324 further has a second opening 43243. The second opening 43243 is located on the opposite side of the second opening 43242 from the first opening 43241 in the first direction. The second opening 43243 is located between the first opening 43241 and the first side wall 43211 in the first direction.

As shown in FIG. 2, the second developing unit 4322 is located on the opposite side of the photosensitive drum 41K from the first developing unit 4321. The second developing unit 4322 is located on the opposite side of the first developing unit 4321 from the wall 4324. In other words, the wall 4324 is located between the first developing unit 4321 and the second developing unit 4322. The second developing unit 4322 is connected to the wall 4324. When the toner cartridge 5K is attached to the main body housing 2, the second developing unit 4322 is located above the cartridge mounting portion 4325. When the toner cartridge 5K is attached to the drum cartridge 4K and the drum cartridge 4K is attached to the main body housing 2, the second developing unit 4322 is located above the toner cartridge 5K.

As shown in Figures 2 and 8, the second developing unit 4322 has a toner receiving port 43221 (see Figure 2) and a toner return port 43222 (see Figure 8). In other words, the developing housing 432K has a toner receiving port 43221 and a toner return port 43222.

As shown in FIG. 2, the toner receiving port 43221 can receive toner supplied from the toner cartridge 5K. The toner receiving port 43221 communicates with the first opening 43241. In other words, the first opening 43241 communicates with the toner receiving port 43221 of the second developing unit 4322. As a result, the toner receiving port 43221 of the second developing unit 4322 communicates with the internal space of the first developing unit 4321. The toner receiving port 43221 is located in the center of the second developing unit 4322 in the first direction.

As shown in FIG. 8, the toner return port 43222 can receive toner returning from the first developing unit 4321 to the toner cartridge 5K. The toner return port 43222 communicates with the second opening 43242. This allows the toner return port 43222 to communicate with the internal space of the first developing unit 4321. The toner return port 43222 is located away from the toner receiving port 43221 in the first direction. The toner return port 43222 is located between the toner receiving port 43221 and the second side wall 43212 in the first direction.

Although not shown, the second developing unit 4322 further has a toner return port 43223. The toner return port 43223 communicates with the second opening 43243. The toner return port 43223 is located on the opposite side of the toner receiving port 43221 from the toner return port 43222 in the first direction. The toner return port 43223 is located between the toner receiving port 43221 and the first side wall 43211 in the first direction.

2.5.1.2 Cartridge Mounting Portion 4325
As shown in Fig. 2, the toner cartridge 5K can be attached to the cartridge mounting portion 4325. When the drum cartridge 4K is attached to the main body housing 2, the cartridge mounting portion 4325 is located lower than the second developing portion 4322. The cartridge mounting portion 4325 is connected to the second developing portion 4322, the wall 4324, and the bottom wall 43213. The cartridge mounting portion 4325 has a cylindrical shape. The cartridge mounting portion 4325 extends in the first direction. The internal space of the cartridge mounting portion 4325 communicates with the toner receiving port 43221 and the toner return ports 43222 and 43223.

As shown in FIG. 6, the cartridge mounting portion 4325 has a protruding portion 43251. The protruding portion 43251 protrudes on the opposite side of the second side wall 43212 from the first side wall 43211 in the first direction.

As shown in Figures 5 and 9, the protruding portion 43251 faces the flange 423. The protruding portion 43251 has a waste toner discharge port 432511 (see Figure 5) and a third hole 432512 (see Figure 9). In other words, the cartridge mounting portion 4325 of the drum cartridge 4K has a waste toner discharge port 432511 (see Figure 5) and a third hole 432512 (see Figure 9).

As shown in FIG. 5, the waste toner discharge port 432511 can discharge the waste toner that has passed through the waste toner tube 49K. The waste toner discharge port 432511 communicates with the hole 4231 of the flange 423. This allows the waste toner discharge port 432511 to communicate with the internal space of the second end 492 of the waste toner tube 49K.

As shown in FIG. 9, when the toner cartridge 5K is mounted in the cartridge mounting portion 4325 of the drum cartridge 4K, the third protrusion 513 fits into the third hole 432512. When the toner cartridge 5K is mounted in the cartridge mounting portion 4325 along the first direction, the third hole 432512 receives the third protrusion 513. The third protrusion 513 will be described later.

The third hole 432512 is located on the opposite side of the first side wall 43211 from the waste toner discharge port 432511 in the first direction. In this embodiment, the third hole 432512 is a groove recessed in the first direction.

2.5.2 Supply roller 433K
As shown in FIG. 2, the supply roller 433K supplies toner to the developing roller 431K. The supply roller 433K is disposed in the first developing unit 4321. The supply roller 433K is located on the opposite side of the photosensitive drum 41K with respect to the developing roller 431K. The supply roller 433K extends in a first direction. The supply roller 433K is rotatable about an axis. The axis of the supply roller 433K extends in the first direction. One end of the supply roller 433K in the first direction is supported by the first side wall 43211 (see FIG. 6). The other end of the supply roller 433K in the first direction is supported by the second side wall 43212 (see FIG. 6).

2.5.3 Toner transport member 434K
The toner transport member 434K is disposed between the supply roller 433K and the wall 4324. The toner transport member 434K is located on the opposite side of the photosensitive drum 41K with respect to the supply roller 433K. The toner transport member 434K extends in a first direction. The toner transport member 434K is capable of transporting toner in the first direction. This allows the toner transport member 434K to transport the toner supplied to the first developing unit 4321 in the first direction and supply it to the supply roller 433K. Therefore, even if the dimension of the first opening 43241 and/or the toner receiving port 43221 in the first direction is reduced, the toner can be appropriately supplied to the supply roller 433K. Furthermore, by reducing the dimension of the toner receiving port 43221 in the first direction, it is possible to suppress leakage of toner from the developing device 43K.

One end of the toner transport member 434K in the first direction is supported by the first side wall 43211 (see FIG. 6). The other end of the toner transport member 434K in the first direction is supported by the second side wall 43212 (see FIG. 6).

2.5.4 Development Shutter 44K
As shown in Figures 2 and 3, the development shutter 44K can move between a development open position (see Figure 2) and a development closed position (see Figure 3). As shown in Figures 2 and 10, when the development shutter 44K is located at the development open position, the waste toner discharge port 432511 is open and the toner receiving port 43221 is open. Also, as shown in Figure 8, when the development shutter 44K is located at the development open position, the two toner return ports 43222 and 42223 are open.

As shown in Figures 3 and 11, when the development shutter 44K is located at the development closed position, the development shutter 44K closes the waste toner discharge port 432511 and closes the toner receiving port 43221. Although not shown, when the development shutter 44K is located at the development closed position, the development shutter 44K closes the two toner return ports 43222 and 42223.

As shown in FIG. 5, the development shutter 44K is disposed within the cartridge mounting portion 4325. The development shutter 44K includes a development shutter main body 441 and a side wall 442.

2.5.4.1 Development shutter body 441
The developing shutter body 441 extends in the first direction. The developing shutter body 441 has a cylindrical shape. Therefore, by rotating the developing shutter 44K, the developing shutter 44K can be moved between the developing open position and the developing closed position. As a result, the space in which the developing shutter 44K moves can be reduced.

As shown in Figures 2, 5, 8 and 9, the development shutter body 441 has a first shutter opening 4411 (see Figure 2), a second shutter opening 4413 (see Figure 5), a third shutter opening 4414 (see Figure 8), a groove 4416 (see Figure 9), and a second hole 4412 (see Figure 9). In other words, the development shutter 44K has a first shutter opening 4411, a second shutter opening 4413, a third shutter opening 4414, a groove 4416, and a second hole 4412.

As shown in Figures 2 and 3, the first shutter opening 4411 is located at the center of the development shutter body 441 in the first direction. As shown in Figure 2, when the development shutter 44K is in the development open position, at least a portion of the first shutter opening 4411 communicates with the toner receiving port 43221. As shown in Figure 3, when the development shutter 44K is in the development closed position, the first shutter opening 4411 is separated from the toner receiving port 43221. When the development shutter 44K is in the development closed position, the entire first shutter opening 4411 does not communicate with the toner receiving port 43221.

As shown in Figures 10 and 11, the second shutter opening 4413 is spaced apart from the first shutter opening 4411 in the first direction. As shown in Figure 10, when the development shutter 44K is positioned at the development open position, at least a portion of the second shutter opening 4413 communicates with the waste toner discharge port 432511. As shown in Figure 11, when the development shutter 44K is positioned at the development closed position, the second shutter opening 4413 is spaced apart from the waste toner discharge port 432511. When the development shutter 44K is positioned at the development closed position, the entire second shutter opening 4413 does not communicate with the waste toner discharge port 432511.

As shown in FIG. 8, the third shutter opening 4414 is located on the opposite side of the second shutter opening 4413 with respect to the first shutter opening 4411 in the first direction. When the development shutter 44K is located in the development open position, at least a portion of the third shutter opening 4414 communicates with the toner return port 43222. Although not shown, when the development shutter 44K is located in the development closed position, the third shutter opening 4414 is separated from the toner return port 43222. When the development shutter 44K is located in the development closed position, the entire third shutter opening 4414 does not communicate with the toner return port 43222.

Although not shown, the development shutter 44K further has a third shutter opening 4415. The third shutter opening 4415 is located between the first shutter opening 4411 and the second shutter opening 4413 in the first direction. When the development shutter 44K is located in the development open position, at least a portion of the third shutter opening 4415 communicates with the toner return port 43223. When the development shutter 44K is located in the development closed position, the third shutter opening 4415 does not communicate with the toner return port 43223.

As shown in FIG. 9, when the toner cartridge 5K is mounted in the cartridge mounting portion 4325 of the drum cartridge 4K, the third protrusion 513 of the cartridge housing 51K fits into the groove 4416. When the toner cartridge 5K is mounted in the cartridge mounting portion 4325 along the first direction, the groove 4416 receives the third protrusion 513. The groove 4416 is located at one end of the developing shutter main body 441 in the first direction. The groove 4416 is located on the opposite side of the first shutter opening 4411 with respect to the second shutter opening 4413 in the first direction. The groove 4416 is recessed in the first direction. The groove 4416 extends in the circumferential direction of the developing shutter main body 441.

When the toner cartridge 5K is mounted in the cartridge mounting portion 4325 of the drum cartridge 4K, the second protrusion 527 of the toner shutter 52K fits into the second hole 4412. When the toner cartridge 5K is mounted in the cartridge mounting portion 4325 along the first direction, the second hole 4412 receives the second protrusion 527. The second protrusion 527 will be described later. The second hole 4412 is located at one end of the development shutter main body 441 in the first direction. The second hole 4412 is separated from the groove 4416 in the circumferential direction of the development shutter main body 441. In this embodiment, the second hole 4412 is a groove recessed in the first direction.

2.5.4.2 Sidewall 442
As shown in FIG. 5, the side wall 442 is located at the other end of the developing shutter 44K in the first direction. The side wall 442 closes the other end of the developing shutter body 441 in the first direction. The side wall 442 has two first holes 4421, 4422. In other words, the developing shutter 44K has two first holes 4421, 4422. When the toner cartridge 5K is mounted in the cartridge mounting portion 4325 of the drum cartridge 4K, the first protrusion 525 fits into the first hole 4421. When the toner cartridge 5K is mounted in the cartridge mounting portion 4325, the first protrusion 526 fits into the first hole 4422. The first protrusions 525, 526 will be described later.

2.5.4 First development protrusions 435A, 435B
5 and 6, the first developing protrusion 435A is located on the opposite side of the second side wall 43212 with respect to the first side wall 43211 in the first direction. The first developing protrusion 435A extends in the first direction. The first developing protrusion 435A has a cylindrical shape. The first developing protrusion 435A may be a shaft of the developing roller 431K.

The first developing protrusion 435A fits into the first long hole 4211 of the first side frame 421. When the first developing protrusion 435A is fitted into the first long hole 4211, the first long hole 4211 has some play in the direction in which the first long hole 4211 extends.

The first developing protrusion 435B is located on the opposite side of the first side wall 43211 from the second side wall 43212 in the first direction. The first developing protrusion 435B will be described in the same manner as the first developing protrusion 435A. Therefore, a description of the first developing protrusion 435B will be omitted.

2.5.5 Second development protrusions 436A, 436B
The second developing projection 436A is located on the opposite side of the second side wall 43212 with respect to the first side wall 43211 in the first direction. The second developing projection 436A extends in the first direction. The second developing projection 436A has a cylindrical shape. The second developing projection 436A may be a shaft of the toner transport member 434K.

The second developing protrusion 436A fits into the second long hole 4212 of the first side frame 421. The second developing protrusion 436A is located on the opposite side of the photosensitive drum 41K from the first developing protrusion 435A in the second direction. When the second developing protrusion 436A fits into the second long hole 4212, the second long hole 4212 has some play in the direction in which the second long hole 4212 extends.

The second developing protrusion 436B is located on the opposite side of the second side wall 43212 from the first side wall 43211 in the first direction. The second developing protrusion 436B will be described in the same manner as the second developing protrusion 436A. Therefore, a description of the second developing protrusion 436B will be omitted.

As a result, the developing device 43K is supported by the first side frame 421 and the second side frame 422. The developing device 43K is movable relative to the photosensitive drum 41K in a direction intersecting the first direction. More specifically, the developing device 43K is movable relative to the photosensitive drum 41K in the direction in which the developing roller 431K and the photosensitive drum 41K face each other.

2.6 Cushion member 9K
5, the cushion member 9K is located between the flange 423 of the drum frame 42K and the protruding portion 43251 of the cartridge mounting portion 4325. When the developing device 43K moves relative to the photosensitive drum 41 with the drum cartridge 4K mounted in the main body housing 2, the cushion member 9K allows the cartridge mounting portion 4325 to move relative to the flange 423.

The cushion member 9K is made of a resilient material. In this embodiment, the cushion member 9K is made of sponge. The cushion member 9K is positioned between the flange 423 and the protruding portion 43251 in a slightly compressed state. The cushion member 9K may be attached to the flange 423 and the protruding portion 43251 with double-sided tape or the like.

When the drum cartridge 4K is installed in the main body housing 2 and the developing device 43K moves relative to the photosensitive drum 41K, the cushion member 9K elastically deforms.

More specifically, when the developing device 43K moves in a direction away from the photosensitive drum 41K, the protruding portion 43251 moves in a direction away from the flange 423. Then, the cushion member 9K restores from the compressed state and fills the gap between the protruding portion 43251 and the flange 423.

When the developing device 43K moves toward the photosensitive drum 41K, the protruding portion 43251 moves toward the flange 423. Then, the cushion member 9K is compressed between the protruding portion 43251 and the flange 423.

The cushion member 9K surrounds the waste toner discharge port 432511. The cushion member 9K has an opening 91. The opening 91 allows the passage of waste toner that has passed through the waste toner tube 49K. The opening 91 communicates with the hole 4231 in the flange 423 and the waste toner discharge port 432511. The cushion member 9K surrounding the waste toner discharge port 432511 comes into contact with the flange 423 and the protruding portion 43251, so that the cushion member 9K seals the gap between the flange 423 and the protruding portion 43251. This makes it possible to prevent toner from leaking between the flange 423 and the protruding portion 43251.

2, the toner cartridge 5K is detachable from the cartridge mounting portion 4325 of the drum cartridge 4 along the first direction. The toner cartridge 5K is capable of storing toner to be supplied to the developing housing 432K. When the toner cartridge 5K is mounted in the developing device 43K, the toner cartridge 5K is capable of supplying toner to the developing housing 432K of the developing device 43K. When the drum cartridge 4K is mounted in the main body housing 2 and the toner cartridge 5K is mounted in the cartridge mounting portion 4325, the toner cartridge 5K is located below the photosensitive drum 41K.

As shown in FIG. 12, the toner cartridge 5K includes a cartridge housing 51K, a toner shutter 52K, and an agitator 53K (see FIG. 13).

3.1 Cartridge housing 51K
The cartridge housing 51K is capable of storing toner. More specifically, as shown in Fig. 13, the cartridge housing 51K is capable of separately storing toner and waste toner. The cartridge housing 51K includes a toner storage section 511, a waste toner storage section 512, and a third protrusion 513. The toner storage section 511 and the waste toner storage section 512 are aligned in a first direction. The cartridge housing 51K has a cylindrical shape extending in the first direction.

3.1.1 Toner storage unit 511
The toner storage unit 511 stores the toner to be supplied to the first developing unit 4321. The toner storage unit 511 extends in a first direction. The toner storage unit 511 has a toner discharge port 5111 and two toner receiving ports 5112 and 5113. In other words, the cartridge housing 51K has the toner discharge port 5111 and the two toner receiving ports 5112 and 5113.

When the toner cartridge 5K is attached to the cartridge mounting portion 4325, the toner discharge port 5111 allows the toner contained in the toner storage portion 511 to pass through. The toner discharge port 5111 is located on the peripheral surface of the cartridge housing 51K. The toner discharge port 5111 is located at the center of the toner storage portion 511 in the first direction. When the toner cartridge 5K is attached to the cartridge mounting portion 4325, the toner discharge port 5111 is open upward.

When the toner cartridge 5K is mounted in the cartridge mounting section 4325, the toner receiving ports 5112 and 5113 receive the toner returning from the first developing section 4321. The two toner receiving ports 5112 and 5113 are located on the circumferential surface of the cartridge housing 51K. The toner receiving port 5112 is located away from the toner discharge port 5111 in the first direction. The toner receiving port 5112 is located between the toner discharge port 5111 and the waste toner storage section 512 in the first direction. The toner receiving port 5113 is located on the opposite side of the toner receiving port 5112 with respect to the toner discharge port 5111 in the first direction. When the toner cartridge 5K is mounted in the cartridge mounting section 4325, the two toner receiving ports 5112 and 5113 are open upward.

3.1.2 Waste Toner Storage Unit 512
The waste toner storage unit 512 stores the waste toner transported from the waste toner tube 49K. As shown in Fig. 11, the waste toner storage unit 512 has a waste toner receiving port 5121. When the toner cartridge 5K is mounted in the cartridge mounting unit 4325, the waste toner receiving port 5121 allows the waste toner from the waste toner tube 49K to pass through. The waste toner receiving port 5121 is located on the circumferential surface of the cartridge housing 51K. When the toner cartridge 5K is mounted in the cartridge mounting unit 4325, the waste toner receiving port 5121 opens obliquely upward.

3.1.3 Third protrusion 513
As shown in FIG. 9, when the toner cartridge K is mounted in the cartridge mounting portion 4325, the third protrusion 513 fits into the third hole 432512 of the protruding portion 43251. As a result, when the toner cartridge 5K is mounted in the cartridge mounting portion 4325, the cartridge housing 51K is fixed to the cartridge mounting portion 4325 of the drum cartridge 4K. "The cartridge housing 51K is fixed to the cartridge mounting portion 4325" means that even if the toner shutter 52K moves in the circumferential direction of the cartridge housing 51K relative to the cartridge mounting portion 4325, the cartridge housing 51K does not move in the circumferential direction of the cartridge housing 51K relative to the cartridge mounting portion 4325. Therefore, when the toner cartridge 5K is mounted in the cartridge mounting portion 4325, the toner shutter 52K can be stably moved relative to the cartridge housing 51K.

As shown in FIG. 12, the third protrusion 513 is located on the peripheral surface of the waste toner storage section 512. In other words, the waste toner storage section 512 has the third protrusion 513. The third protrusion 513 protrudes from the peripheral surface of the waste toner storage section 512. The third protrusion 513 is located on the opposite side of the waste toner receiving port 5121 from the toner discharge port 5111 in the first direction (see FIG. 4, FIG. 11, and FIG. 13).

3.2 Toner shutter 52K
The toner shutter 52K is movable between a toner open position (see FIG. 2) and a toner closed position (see FIG. 3).

As shown in Figures 2 and 10, when the toner shutter 52K is in the toner open position, the waste toner receiving port 5121 opens and the toner discharge port 5111 opens. When the toner cartridge 5K is mounted in the cartridge mounting portion 4325 of the drum cartridge 4K, the development shutter 44K is in the development open position, and the toner shutter 52K is in the toner open position, the waste toner receiving port 5121 communicates with the waste toner discharge port 432511, and the toner discharge port 5111 communicates with the toner receiving port 43221.

As shown in FIG. 8, when the toner cartridge 5K is mounted on the drum cartridge 4K, the development shutter 44K is in the development open position, and the toner shutter 52K is in the toner open position, the two toner receiving ports 5112 and 5113 are open, the toner receiving port 5112 communicates with the toner return port 43222, and the toner receiving port 5113 communicates with the toner return port 43223. As a result, when the toner cartridge 5K is mounted on the drum cartridge 4K, the development shutter 44K is in the development open position, and the toner shutter 52K is in the toner open position, the toner can move from the first developing unit 4321 to the cartridge housing 51K through the second opening 43242, the toner return port 43222, and the toner receiving port 5112. Therefore, the toner can be circulated between the first developing unit 4321 and the cartridge housing 51K. As a result, the deterioration of the toner can be prevented from affecting image formation.

As shown in Figures 3 and 11, when the toner shutter 52K is in the toner closed position, the toner shutter 52 closes the waste toner receiving port 5121 and closes the toner discharge port 5111. This makes it possible to prevent waste toner from leaking from the toner cartridge 5K and the drum cartridge 4K by removing the toner cartridge 5K from the cartridge mounting section 4325 with the development shutter 44K in the development closed position and the toner shutter 52K in the toner closed position.

Although not shown, when the toner shutter 52K is in the toner closed position, the toner shutter 52K closes the two toner receiving ports 5112 and 5113.

As shown in Figures 12 and 13, the toner shutter 52K includes a toner shutter body 521, a first side wall 522, a second side wall 523, two first protrusions 525 and 526, a second protrusion 527, and a handle 524.

3.2.1 Toner shutter body 521
The toner shutter body 521 extends in the first direction. The toner shutter body 521 has a cylindrical shape. The cartridge housing 51K is located inside the toner shutter body 521. Therefore, by rotating the toner shutter 52K, the toner shutter 52K can be smoothly moved between the toner open position and the toner closed position along the cartridge housing 51K. As a result, the space in which the toner shutter 52K moves can be reduced.

The toner shutter body 521 has a first shutter opening 5211, a second shutter opening 5212, two third shutter openings 5213 and 5214, and an elongated hole 5215. In other words, the toner shutter 52K has a first shutter opening 5211, a second shutter opening 5212, two third shutter openings 5213 and 5214, and an elongated hole 5215.

The first shutter opening 5211 is located at the center of the toner shutter body 521 in the first direction. As shown in FIG. 2, when the toner shutter 52K is in the toner open position, at least a part of the first shutter opening 5211 communicates with the toner discharge port 5111. When the toner cartridge 5K is mounted in the cartridge mounting section 4325, the development shutter 44K is in the development open position, and the toner shutter 52K is in the toner open position, the toner discharge port 5111, the first shutter opening 5211 of the toner shutter 52K, the first shutter opening 4411 of the development shutter 44K, and the toner receiving port 43221 communicate with each other. As shown in FIG. 3, when the toner shutter 52K is in the toner closed position, the first shutter opening 5211 is separated from the toner discharge port 5111. When the toner shutter 52K is in the toner closed position, the entire first shutter opening 5211 does not communicate with the toner discharge port 5111.

As shown in FIG. 10, the second shutter opening 5212 is separated from the first shutter opening 5211 in the first direction. When the toner shutter 52K is in the toner open position, at least a portion of the second shutter opening 5212 communicates with the waste toner receiving port 5121. When the toner cartridge 5K is mounted in the cartridge mounting portion 4325, the development shutter 44K is in the development open position, and the toner shutter 52K is in the toner open position, the waste toner receiving port 5121, the second shutter opening 5212 of the toner shutter 52K, the second shutter opening 4413 of the development shutter 44K, the waste toner discharge port 432511, the opening 91 of the cushion member 9, and the hole 4231 of the flange 423 communicate with each other.

As shown in FIG. 11, when the toner shutter 52K is in the toner closed position, the second shutter opening 5212 is separated from the waste toner receiving port 5121. When the toner shutter 52K is in the toner closed position, none of the second shutter opening 5212 communicates with the waste toner receiving port 5121.

12, the third shutter opening 5213 is located between the first shutter opening 5211 and the second shutter opening 5212 in the first direction. As shown in FIG. 8, when the toner shutter 52K is in the toner open position, at least a part of the third shutter opening 5213 communicates with the toner receiving port 5112. When the toner cartridge 5K is mounted in the cartridge mounting section 4325, the development shutter 44K is in the development open position, and the toner shutter 52K is in the toner open position, the toner receiving port 5112, the third shutter opening 5213 of the toner shutter 52K, the third shutter opening 4414 of the development shutter 44K, and the toner return port 43222 communicate with each other. Although not shown, when the toner shutter 52K is in the toner closed position, the third shutter opening 5213 is separated from the toner receiving port 5112. When the toner shutter 52K is in the toner closed position, none of the third shutter openings 5214 communicate with the toner receiving port 5113.

As shown in FIG. 12, the third shutter opening 5214 is located on the opposite side of the first shutter opening 5211 from the third shutter opening 5213 in the first direction. The third shutter opening 5214 will be described in the same manner as the third shutter opening 5213. Therefore, the description of the third shutter opening 5214 will be omitted.

The third protrusion 513 of the cartridge housing 51K fits into the long hole 5215. When the third protrusion 513 is fitted into the long hole 5215, the third protrusion 513 protrudes from the toner shutter body 521. The long hole 5215 is located on the opposite side of the toner discharge port 5111 from the third shutter opening 5213 in the first direction. The long hole 5215 extends in the circumferential direction of the toner shutter body 521.

Although not shown, the image forming apparatus 1 may also include a seal member. When the toner cartridge 5K is mounted in the drum cartridge 4K, the seal member seals between the development shutter 44K and the toner shutter 52K. When the toner cartridge 5K is mounted in the drum cartridge 4K, the seal member seals between the development shutter main body 441 and the toner shutter main body 521. When the toner cartridge 5K is mounted in the drum cartridge 4K, the development shutter 44K is in the development open position, and the toner shutter 52K is in the toner open position, the seal member surrounds the first shutter opening 4411 and the first shutter opening 5211, surrounds the second shutter opening 4413 and the second shutter opening 5212, surrounds the third shutter opening 4414 and the third shutter opening 5213, and surrounds the third shutter opening 4415 and the third shutter opening 5214. The seal member may be one member or multiple members.

3.2.2 First side wall 522 and second side wall 523
The first side wall 522 closes the other end of the toner shutter body 521 in the first direction. The second side wall 523 closes one end of the toner shutter body 521 in the first direction.

3.2.3 First protrusions 525, 526
The two first protrusions 525, 526 are located at the other end of the toner shutter 52K in the first direction. The two first protrusions 525, 526 are located on the opposite side of the waste toner receiving port 5121 with respect to the toner discharge port 5111 in the first direction. The two first protrusions 525, 526 are provided on the first side wall 522. The two first protrusions 525, 526 are located on the opposite side of the second side wall 523 with respect to the first side wall 522 in the first direction. Each of the two first protrusions 525, 526 extends in the first direction. The first protrusion 526 is located on the opposite side of the first protrusion 525 with respect to the axis of the toner shutter main body 521.

When the toner cartridge 5K is mounted in the cartridge mounting portion 4325, the first protrusion 525 fits into the first hole 4421 (see FIG. 5). When the toner cartridge 5K is mounted in the cartridge mounting portion 4325, the first protrusion 526 fits into the first hole 4422 (see FIG. 5).

3.2.4 Second protrusion 527
As shown in Fig. 13, the second protrusion 527 is located at one end of the toner shutter 52K in the first direction. The second protrusion 527 is located on the opposite side of the toner discharge port 5111 with respect to the waste toner receiving port 5121 in the first direction (see Figs. 4 and 10). The second protrusion 527 is provided on the toner shutter main body 521. The second protrusion 527 protrudes from the toner shutter main body 521. When the toner shutter 52K is located in the toner closing position, the second protrusion 527 is located on the opposite side of the waste toner storage section 512 from the third protrusion 513.

As shown in FIG. 9, when the toner cartridge 5K is attached to the drum cartridge 4K, the second protrusion 527 fits into the second hole 4412.

That is, when the toner cartridge 5K is mounted in the cartridge mounting section 4325, the first protrusion 525 fits into the first hole 4421, the first protrusion 526 fits into the first hole 4422, and the second protrusion 527 fits into the second hole 4412. This allows the development shutter 44K to move together with the toner shutter 52K when the toner cartridge 5K is mounted in the drum cartridge 4K. In detail, as shown in FIG. 2 and FIG. 3, when the toner shutter 52K moves from the toner closed position to the toner open position when the toner cartridge 5K is mounted in the cartridge mounting section 4325, the development shutter 44K moves from the development closed position to the development open position in conjunction with the toner shutter 52K. Also, when the toner shutter 52K moves from the toner open position to the toner closed position when the toner cartridge 5K is mounted in the cartridge mounting section 4325, the development shutter 44K moves from the development open position to the development closed position in conjunction with the toner shutter 52K.

3.2.5 Handle 524
13, the handle 524 is operated by a user. This allows the user to hold the handle 524 and move the toner shutter 52K between the toner closed position and the toner open position. The handle 524 is located on the opposite side of the first side wall 522 with respect to the second side wall 523 in the first direction. The handle 524 is provided on the second side wall 523.

3.3 Agitator 53K
As shown in Fig. 2, when the toner cartridge 5K is attached to the drum cartridge 4K, the agitator 53K can transport the toner in the toner storage unit 511 toward the first developing unit 4321. As shown in Fig. 13, the agitator 53K is located in the toner storage unit 511 of the cartridge housing 51K. The agitator 53K is rotatable. The agitator 53K includes a shaft 531, a first blade 532, a plurality of second blades 533, and a plurality of third blades 534.

3.3.1 Shaft 531
The shaft 531 is rotatably supported by the toner storage unit 511. The shaft 531 is rotatable about a rotation axis 5311 (see FIG. 2). The rotation axis 5311 extends in a first direction. The rotation axis 5311 of the shaft 531 coincides with the axis of the cartridge housing 51K. As a result, when the toner cartridge 5K is attached to the drum cartridge 4K, the development shutter 44K is located at the development open position, and the toner shutter 52K is located at the toner open position, when the agitator 53K rotates, the agitator 53K can smoothly transport the toner contained in the cartridge housing 51K to the first development unit 4321.

3.3.2 First blade 532
The first blade 532 is rotatable together with the shaft 531. The first blade 532 is supported at a central portion of the shaft 531 in the first direction. The first blade 532 is flexible. As shown in FIG. 2 , the first blade 532 has a first end 5321 and a second end 5322. The first end 5321 of the first blade 532 is fixed to the shaft 531. The second end 5322 of the first blade 532 is located away from the first end 5321.

When the toner cartridge 5K is mounted on the drum cartridge 4K, the developer shutter 44 is in the developer open position, and the toner shutter 52 is in the toner open position, and the agitator 53K rotates, the second end 5322 of the first blade 532 reaches the height of the first opening 43241 in the vertical direction. When the toner cartridge 5K is mounted on the drum cartridge 4K, the developer shutter 44 is in the developer open position, and the toner shutter 52 is in the toner open position, and the agitator 53K rotates, the second end 5322 of the first blade 532 reaches above the bottom wall 43213 in the vertical direction. In addition, when the second end 5322 of the first blade 532 reaches the height of the first opening 43241, the height of the first blade 532 overlaps with the toner conveying member 434K in the vertical direction. As a result, even if the cartridge housing 51K of the toner cartridge 5K is positioned below the second developing unit 4322 when the toner cartridge 5K is attached to the drum cartridge 4K, the agitator 53K can stably supply toner from the cartridge housing 51K to the first developing unit 4321 through the second developing unit 4322 and the first opening 43241.

When the second end 5322 reaches the height of the first opening 43241, the portion of the first blade 532 between the first end 5321 and the second end 5322 passes through the toner discharge port 5111, the first shutter opening 5211 of the toner shutter 52K, the first shutter opening 4411 of the development shutter 44K, and the toner receiving port 43221.

In this state, the rotation of the agitator 53K may stop. When the toner shutter 52K moves from the toner open position to the toner closed position, the toner shutter 52K moves in the opposite direction to the rotation direction of the agitator 53K. Therefore, when the toner shutter 52K moves from the toner open position to the toner closed position with the second end 5322 of the first blade 532 of the agitator 53K reaching the height of the first opening 43241 in the vertical direction, the first blade 532 is pushed by the toner shutter 52K and moves within the toner discharge port 5111 while bending. Therefore, it is possible to prevent the first blade 532 from being pinched between the toner shutter 52K and the cartridge housing 51K, and the toner shutter 52 can be stably moved from the toner open position to the toner closed position.

In addition, when the development shutter 44K moves from the development open position to the development closed position, the development shutter 44K moves in the direction opposite to the rotation direction of the agitator 53K. This prevents the first blade 532 of the agitator 53K from being pinched between the development shutter 44K and the cartridge mounting portion 4325, and allows the development shutter 44K to be stably moved from the development open position to the development closed position.

3.3.3 Multiple second blades 533
13 , the second blades 533 are located between the first blade 532 and the first side wall 522 in the first direction. The second blades 533 are supported by the shaft 531. When the agitator 53K rotates, the second blades 533 agitate the toner in the toner storage unit 511 and transport the toner toward the first blade 532.

3.3.4 Multiple third blades 534
The multiple third blades 534 are located between the first blade 532 and the waste toner storage unit 512 in the first direction. The multiple third blades 534 are supported by the shaft 531. When the agitator 53K rotates, the multiple third blades 534 agitate the toner in the toner storage unit 511 and transport the toner toward the first blade 532.

4. Effects (1) As shown in FIG. 2, when the toner cartridge 5K is attached to the drum cartridge 4K, the developer shutter 44K is located at the developer open position, and the toner shutter 52K is located at the toner open position, when the agitator 53K rotates, the second end 5322 of the first blade 532 reaches the height of the first opening 43241 in the vertical direction.

Therefore, even if the cartridge housing 51K of the toner cartridge 5K is positioned lower than the second developing unit 4322 when the toner cartridge 5K is attached to the drum cartridge 4K, the agitator 53K can stably supply toner from the cartridge housing 51K to the first developing unit 4321 through the second developing unit 4322 and the first opening 43241.

As shown in FIG. 3, when the development shutter 44K is in the development closed position, the development shutter 44K closes the toner receiving port 43221 of the second development unit 4322. When the toner shutter 52K is in the toner closed position, the toner shutter 52K closes the toner discharge port 5111 of the cartridge housing 51K.

Therefore, by removing the toner cartridge 5K from the drum cartridge 4K with the development shutter 44K in the development closed position and the toner shutter 52K in the toner closed position, it is possible to prevent toner from leaking from the toner cartridge 5K and the drum cartridge 4K.

As a result, the drum cartridge 4K and toner cartridge 5K can be replaced separately and smoothly.

(2) As shown in FIG. 10, when the toner cartridge 5K is mounted in the cartridge mounting portion 4325 of the drum cartridge 4K, the waste toner removed from the peripheral surface of the photosensitive drum 41K by the drum cleaner 47K is accommodated in the waste toner storage portion 512 of the toner cartridge 5K through the waste toner tube 49K and the waste toner receiving port 5121. The waste toner storage portion 512 is replaced together with the toner storage portion 511 when the toner cartridge 5K is replaced. Therefore, the waste toner storage portion 512 can stably accommodate the waste toner without increasing its capacity.

The cushion member 9K is located between the flange 423 to which the second end 492 of the waste toner tube 49K is connected and the protruding portion 43251 of the cartridge mounting portion 4325.

As a result, when the toner cartridge 5K is mounted in the cartridge mounting portion 4325 and the drum cartridge 4K is mounted in the main housing 2, when the developing device 43K moves relative to the photosensitive drum 41K, the cartridge mounting portion 4325 can move relative to the flange 423, and leakage of waste toner from between the flange 423 and the protruding portion 43251 can be prevented.

REFERENCE SIGNS LIST 1 Image forming apparatus 2 Main body housing 4 Drum cartridge 41 Photosensitive drum 411 Drum shaft 42 Drum frame 421 First side frame 422 Second side frame 423 Flange 43 Developing device 431 Developing roller 432 Developing housing 4321 First developing section 43211 First side wall 43212 Second side wall 4322 Second developing section 43221 Toner receiving port 43222 Toner return port 4324 Wall 43241 First opening 43242 Second opening 432511 Waste toner discharge port 432512 Third hole 433 Supply roller 434 Toner transport member 44 Developing shutter 4412 Second hole 4421 First hole 47 Drum cleaner 48 Waste toner transport member 49 Waste toner tube 491 First end 492 Second end 5 Toner cartridge 511 Toner storage section 5111 Toner discharge port 5112 Toner receiving port 512 Waste toner storage section 5121 Waste toner receiving port 52 Toner shutter 524 Handle 525 First protrusion 527 Second protrusion 53 Agitator 531 Shaft 532 First blade 5321 First end 5322 Second end 7 Transfer device 9 Cushion member 91 Opening

Claims (11)

A main body housing;
A drum cartridge that can be attached to the main body housing,
a photosensitive drum rotatable about an axis extending in a first direction;
a developing device having a developing roller and a developing housing supporting the developing roller;
A drum cartridge having
a toner cartridge capable of accommodating toner to be supplied to the developing housing, the toner cartridge being attachable to the drum cartridge;
a transfer device that is positioned above the photosensitive drum when the drum cartridge is attached to the main body housing and transfers the toner on the photosensitive drum to a sheet;
Equipped with
The developing housing includes:
a first developing unit supporting the developing roller;
a second developing unit that is located above the toner cartridge and on the opposite side of the photosensitive drum with respect to the first developing unit when the toner cartridge is attached to the drum cartridge, the second developing unit having a toner receiving port and communicating with the first developing unit;
a wall located between the first developing unit and the second developing unit, the wall having a first opening communicating with the first developing unit and the second developing unit;
having
The developing device is
a development shutter movable between a development closed position where the toner receiving opening is closed and a development open position where the toner receiving opening is opened;
The toner cartridge includes:
a cartridge housing capable of accommodating toner, the cartridge housing having a toner discharge port;
a toner shutter movable between a toner closing position at which the toner discharge port is closed and a toner opening position at which the toner discharge port is opened;
a rotatable agitator located within the cartridge housing, the agitator comprising a shaft and a vane rotatable with the shaft, the vane having a first end fixed to the shaft and a second end spaced from the first end;
Equipped with
When the toner cartridge is attached to the drum cartridge, the developer shutter is positioned at the developer open position, and the toner shutter is positioned at the toner open position, the toner discharge port communicates with the toner receiving port,
an image forming apparatus characterized in that, when the toner cartridge is attached to the drum cartridge, the development shutter is positioned at the development open position, and the toner shutter is positioned at the toner open position, and the agitator rotates, the second end of the blade reaches the height of the first opening in the vertical direction. The image forming apparatus according to claim 1, characterized in that when the toner shutter moves from the toner open position to the toner closed position, the toner shutter moves in a direction opposite to the rotation direction of the agitator. The image forming apparatus according to claim 1 or 2, characterized in that when the developing shutter moves from the developing open position to the developing closed position, the developing shutter moves in a direction opposite to the rotation direction of the agitator. The developing device is
a supply roller for supplying toner to the developing roller, the supply roller being supported by the first developing unit;
4. The image forming apparatus according to claim 1, further comprising: a toner transport member capable of transporting toner in the first direction, the toner transport member being disposed between the supply roller and the wall. The image forming device according to claim 4, characterized in that the blade has a height that overlaps with the toner transport member in the vertical direction when the second end reaches the height of the first opening. The developing housing includes:
a second opening located away from the first opening in the first direction and communicating with the first developing unit;
a toner return opening located away from the toner receiving opening in the first direction and communicating with the second opening;
the cartridge housing has a toner receiving opening located away from the toner discharge opening in the first direction;
6. The image forming apparatus according to claim 1, wherein the toner receiving port communicates with the toner return port when the toner cartridge is attached to the drum cartridge, the development shutter is positioned at the development open position, and the toner shutter is positioned at the toner open position. the cartridge housing has a cylindrical shape extending in the first direction,
7. The image forming apparatus according to claim 1, wherein the rotation axis of the shaft coincides with an axis of the cartridge housing. The image forming device according to any one of claims 1 to 7, characterized in that the toner shutter has a handle. the toner shutter has a first protrusion,
9. The image forming apparatus according to claim 1, wherein the developing shutter has a first hole into which the first protrusion fits when the toner cartridge is attached to the drum cartridge. the toner cartridge is detachably attached to the drum cartridge along the first direction,
the first protrusion is located at one end of the toner shutter in the first direction,
the toner shutter has a second protrusion located at the other end of the toner shutter in the first direction,
10. The image forming apparatus according to claim 9, wherein the developing shutter has a second hole into which the second protrusion fits when the toner cartridge is attached to the drum cartridge. the cartridge housing has a third projection,
11. The image forming apparatus according to claim 1, wherein the drum cartridge has a third hole into which the third protrusion fits when the toner cartridge is attached to the drum cartridge.

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