JP4775514B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a laser printer.

As an image forming apparatus, a so-called tandem type color printer in which a plurality of photosensitive drums are arranged in parallel along a horizontal direction is known (for example, see Patent Document 1).
The printer described in Patent Document 1 includes a photosensitive unit that is a group of a plurality of photosensitive drums, a developing unit that is disposed below the photosensitive unit and functions to form a toner image on each photosensitive drum. And a belt-like intermediate transfer member to which a toner image formed on each photosensitive drum is transferred.

The developing unit is provided with the same number of developing units as the photosensitive drums arranged in parallel along the horizontal direction. Each developing device includes a developing device case for storing toner, a developing roller and the like disposed above the developing device case.
In the printer described in Patent Document 1, the toner accommodated in the developing device case of each developing device is conveyed upward and supplied to the developing roller, and is further conveyed upward and supplied to the corresponding photosensitive drum. As a result, a toner image is formed on the photosensitive drum. The toner images formed on the respective photosensitive drums are transferred onto the intermediate transfer member, and then transferred from the intermediate transfer member to the sheet. Thereby, a color image is formed on the paper.

In the printer described in Patent Document 1, each of the photosensitive unit and the developing unit can be pulled out from the printer main body along the arrangement direction of the plurality of photosensitive drums for maintenance. Then, each developing device can be drawn upward with respect to the drawn developing device unit.
Unlike the printer described in Patent Document 1, in the printer main body, one side surface in the direction orthogonal to the arrangement direction of the plurality of photosensitive drums (the axial direction of the photosensitive drums) is opened, and the photosensitive drum and the developing device are opened. A configuration in which each of these is pulled out from the one side surface is conceivable. With this configuration, members that are normally disposed on the one side surface of the printer main body (such as a driving force transmission member and a power supply member for the photosensitive drum and the developing device) cannot be disposed, and the degree of freedom in designing the printer Will be lower.

  However, in the printer described in Patent Document 1, since each of the photoreceptor unit and the developer unit is pulled out along the arrangement direction, the degree of freedom in designing the printer as compared with the configuration in which these units are pulled out from the one side surface. Is expensive.

JP 2006-184552 A

In general, replenishment of toner, that is, replacement of the developer case in the printer of Patent Document 1, is maintenance that is particularly frequently performed in the printer.
However, in the printer described in Patent Document 1, the developer case that is accessed frequently is arranged on the lower side of each developer unit, so that the developer case is replenished with toner or the developer case itself is replaced. In order to do this, first, the developing roller on the upper side of the developing device must be removed, which requires time and labor for maintenance of the developing device case.

Further, when the photosensitive unit and the developing unit are pulled out as a unit, the photosensitive unit above the developing unit must be removed in order to remove the developing roller and the like. More time is required for case maintenance.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to improve the maintainability of a developer container that is installed in a developing device and contains a developer in a configuration in which a plurality of developing devices are disposed below a plurality of photosensitive drums arranged in parallel. An object of the present invention is to provide an image forming apparatus capable of achieving the above.

  In order to achieve the above object, an invention according to claim 1 is an image forming apparatus, wherein the apparatus main body, a plurality of photosensitive drums on which electrostatic latent images are formed and arranged in parallel, and the corresponding photosensitive drums. A plurality of developing devices for developing an electrostatic latent image formed on the corresponding photosensitive drum, and a plurality of the photosensitive drums and the developing device provided in the apparatus main body. And a support member that can be pulled out from the apparatus main body along the arrangement direction of the plurality of photosensitive drums, and a developing unit that is provided in each developing device and that develops the electrostatic latent image on the corresponding photosensitive drum A developer container that is detachable along the axial direction of the photosensitive drum with respect to the developing device supported by the support member in a state in which the developer is accommodated and the support member is pulled out from the apparatus main body; The The developer container includes a developer container that contains the developer, and an agitator that is provided in the developer container and rotates around a rotation axis extending in a predetermined direction to agitate the developer. And the developer accommodating portion includes a first arc wall that is curved in an arc shape with a reference line extending in the predetermined direction outside the developer accommodating portion in the radial direction of the rotation shaft as a center of curvature. The first arc wall is characterized in that a first opening is formed on the upstream side in the passing direction of the rotating stirring member so as to communicate the inside and outside of the developer accommodating portion.

  According to a second aspect of the present invention, there is provided a shutter according to the first aspect of the present invention, wherein the shutter allows or restricts the movement of the developer by opening and closing between the developer container and the corresponding photosensitive drum. The developer container includes an operation unit provided upstream of the corresponding developer device in the mounting direction of the developer container and operated to open and close the shutter. Yes.

  According to a third aspect of the present invention, in the second aspect of the present invention, the stirring member provided in the developer container and stirring the developer by transmitting a driving force; and the developer It is provided with the transmission part which is provided in the said mounting direction downstream in a container, receives the driving force from the said apparatus main body, and transmits to the said stirring member by being connected with the said apparatus main body.

According to a fourth aspect of the invention, there is provided the first aspect of the invention according to any one of the first to third aspects, wherein the first opening is opened and closed by moving along a circumferential direction of the first arc wall. It is characterized by having a shutter.
According to a fifth aspect of the present invention, in the invention of the fourth aspect, the stirring member is supported by the hard support portion that extends outward in the radial direction from the rotating shaft, and the support portion. And a stirrer having flexibility and extending outward in the radial direction.

The invention described in claim 6 is characterized in that, in the invention described in claim 4 or 5, the cross section of the developer accommodating portion when viewed from the predetermined direction is substantially circular.
The invention according to claim 7 is the invention according to any one of claims 4 to 6, wherein the first shutter is supported by the developer accommodating portion at a plurality of locations in the predetermined direction. It is characterized by.

  The invention according to claim 8 is the invention according to any one of claims 4 to 7, wherein each of the developing devices includes a housing in which the corresponding developer container is detachably mounted; A second arcuate wall provided in a case, curved in an arc shape along the first arcuate wall of the corresponding developer container, and disposed opposite to the first arcuate wall; and supported by the case A developer carrying member for carrying a developer to be supplied to the electrostatic latent image formed on the corresponding photosensitive drum, and an outer peripheral surface supported by the casing so as to be along the second arc wall. And a supply roller for supplying the developer in the developer container to the developer carrying member.

According to a ninth aspect of the present invention, in the invention according to the eighth aspect, in each of the developing devices, the second arc wall is disposed opposite to the first opening of the corresponding developer container. A second opening that faces the supply roller is formed, and each developing device includes a second shutter that opens and closes the second opening.
The invention according to claim 10 is the invention according to claim 9, wherein each of the developing devices is provided in the housing and has a center of curvature of the first arc wall of the corresponding developer container. A rotation member that is rotatable about a reference line that extends in the predetermined direction is provided, and the second shutter is supported by the rotation member.

An eleventh aspect of the invention includes the operation portion according to the tenth aspect of the invention, which is provided in each developer container and engages with the rotating member of the corresponding developing device. It is characterized by that.
The invention according to claim 12 is the invention according to claim 11, wherein the first shutter is provided with a first engagement portion, and the second shutter is provided with a second engagement portion. In each of the developing devices, the first engagement portion and the second engagement portion are engaged with each other in the state where the developer container is mounted on the casing, and the first shutter The opening / closing operation of the first opening according to the above and the opening / closing operation of the second opening by the second shutter are interlocked with each other.

The invention according to claim 13 is the invention according to any one of claims 9 to 12, wherein in each of the developing devices, the supply roller is disposed at a position higher than the developer container. It is a feature.
The invention according to claim 14 is the invention according to claim 13, wherein in each of the developing devices, the second arc wall bulges downward, and the second arc wall has the first arc A feature is that a portion at a position lower than the lower end of the two openings is provided.

According to the first aspect of the present invention, the image forming apparatus includes a plurality of developing devices for developing the electrostatic latent images formed on the corresponding photosensitive drums below the plurality of photosensitive drums arranged in parallel. Is arranged. Each developing device is disposed below the corresponding photosensitive drum.
The apparatus main body of the image forming apparatus is provided with a support member that supports the plurality of photosensitive drums and the developing device. The support member can be pulled out from the apparatus main body along the arrangement direction of the plurality of photosensitive drums.

Each developing device is provided with a developer container that contains a developer for developing the electrostatic latent image on the corresponding photosensitive drum.
The developer container is detachable along the axial direction of the photosensitive drum with respect to the developing device supported by the support member in a state where the support member is pulled out from the apparatus main body. That is, the developer container can be easily attached to and detached from the developing device without taking the trouble of removing the photosensitive drum above the developing device.

As a result, in a configuration in which a plurality of developing devices are arranged below the plurality of photosensitive drums arranged in parallel, the maintainability of the developer container provided in the developing device can be improved.
In the developer container, a stirring member is provided in the developer container that stores the developer. The agitating member agitates the developer in the developer accommodating portion by rotating around a rotation axis extending along a predetermined direction (hereinafter, simply referred to as “predetermined direction”). Here, the developer accommodating portion has a first arc wall. The first arc wall has a curvature centered on a reference line extending in a predetermined direction outside the developer accommodating portion in the radial direction of the rotating shaft of the stirring member (hereinafter, sometimes simply referred to as “radial direction”). It is curved in a circular arc shape so as to be recessed toward the accommodating portion. Therefore, the stirring member in the developer accommodating portion can contact (pass through the first arc wall) the first arc wall that is recessed toward the developer accommodating portion when rotating. In the first arc wall, on the upstream side in the passing direction of the rotating stirring member, a first opening for communicating the inside and outside of the developer accommodating portion is formed. Accordingly, the first opening through which the developer accommodated in the developer accommodating portion is sent out toward the outside of the developer accommodating container is arranged on the rotation locus of the agitating member, and the rotating agitating member is Thus, the stirring member can be opposed to the downstream side in the rotation direction. As a result, the developer sent in the rotating direction of the stirring member by the rotating stirring member is efficiently sent to the first opening. Therefore, in the developer container, the developer stored in the developer storage portion is sent to the outside. It can be sent out efficiently.
According to the second aspect of the present invention, in the image forming apparatus, the shutter allows or restricts the movement of the developer by opening and closing between the developer container and the corresponding photosensitive drum.

  In the developer container, an operation operated to open and close the shutter on the upstream side in the mounting direction of the developer container with respect to the corresponding developing device (hereinafter, simply referred to as “mounting direction”). Is provided. Therefore, the shutter can be easily opened and closed by operating the operation unit on the upstream side in the mounting direction, which is an easily accessible location in the developer container.

According to the third aspect of the present invention, the developer container is provided with a stirring member that stirs the developer by transmitting the driving force.
A transmission unit that receives a driving force from the apparatus main body and transmits it to the stirring member by being connected to the apparatus main body is provided on the downstream side in the mounting direction of the developer container.
As a result, when the developer container is completely attached to the developing device, the transmission unit can be connected to the apparatus main body, so that the transmission unit is connected to the apparatus main body while the developer container is attached to the developing device. Compared to the case, the developer container can be smoothly attached to the developing device.

  In addition, by providing the transmission unit on the downstream side in the mounting direction of the developer container, a space for providing the operation unit on the upstream side in the mounting direction of the developer container can be secured.

  According to the invention described in claim 4, since the first shutter opens and closes the first opening by moving along the circumferential direction of the first arc wall, the passage of the developer in the first opening is appropriately performed. Can be allowed or regulated.

According to the fifth aspect of the present invention, the stirring member is supported by the hard support portion extending radially outward from the rotation shaft thereof, and is supported by the support portion, extends radially outward from the support portion, and has flexibility. And a stirring part.
In this case, when the stirring member rotates, the stirring unit supported by the support unit becomes appropriate, so that a large amount of developer can be sent in the rotation direction of the stirring member. In addition, since the agitating portion bends moderately when passing through the first arc wall, the agitating portion can be prevented from being caught by the first arc wall, and smooth rotation of the agitating member can be realized.

  According to the sixth aspect of the present invention, since the cross section of the developer accommodating portion when viewed from a predetermined direction is substantially circular, it substantially coincides with the rotation trajectory of the agitating member. The developer in the section can be sent without leakage in the rotation direction of the stirring member. Thereby, the developer can be sent to the first opening more efficiently. The stirring member can uniformly stir the entire developer in the developer accommodating portion.

According to the seventh aspect of the present invention, since the first shutter is supported by the developer accommodating portion at a plurality of locations in the predetermined direction, the first shutter can be operated in a stable posture as compared with the case where the first shutter is supported at one location. One opening can be opened and closed.
According to the eighth aspect of the present invention, each developing device includes a housing in which a corresponding developer container is detachably mounted.

The casing is provided with a second arc wall that is curved in an arc shape so as to be along the first arc wall of the corresponding developer container and is disposed opposite to the first arc wall. In other words, the second arc wall bulges in an arc shape toward the first arc wall of the corresponding developer container.
In each developing device, a developer carrying body that carries the developer supplied to the electrostatic latent image formed on the corresponding photosensitive drum and a developer in the corresponding developer container are developed by the housing. A supply roller that supplies the carrier is supported.

Here, since the supply roller is supported by the casing so that the outer peripheral surface is along the second arc wall, in each developing device, the supply roller can be compactly fitted to the inner area of the second arc wall. Can be placed. As a result, the entire developing device can be reduced in size.
According to the ninth aspect of the present invention, in each developing device, the second arc wall is formed so as to face the first opening of the corresponding developer container, and the second opening facing the supply roller is formed. The second shutter opens and closes the second opening. Therefore, when the second shutter opens the second opening in the state where the corresponding first opening of the developer container is opened, the developer can be moved between the developer container and the supply roller, When the second shutter closes the second opening, the movement of the developer between the developer container and the supply roller can be restricted.

According to the tenth aspect of the present invention, the housing of each developing device is provided with the rotating member. The rotation member is rotatable about a reference line extending in a predetermined direction through the center of curvature of the first arc wall of the corresponding developer container.
Here, since the second shutter is supported by the rotating member, the second shutter can be rotated and the second opening can be opened and closed by a simple operation of rotating the rotating member. it can.

According to the eleventh aspect of the present invention, each developer container is provided with an operating portion that engages with a rotating member of the corresponding developing device. Therefore, by operating the operation part of each developer container, the rotation member and the second shutter of the corresponding developing device can be easily rotated and the second opening can be opened and closed.
According to the twelfth aspect of the present invention, in each of the developing devices, the first engaging portion of the first shutter and the second engaging portion of the second shutter in a state where the developer container is mounted on the housing. Is engaged, and the opening and closing operation of the first opening by the first shutter and the opening and closing operation of the second opening by the second shutter are interlocked, so that the first opening and the second opening can be opened and closed at once, Convenience is good.

According to the thirteenth aspect of the present invention, since the supply roller is arranged at a position higher than the developer container in each developing device, the developer in the developer container is conveyed upward and supplied to the supply roller. Must.
However, in the developer container in which the first opening is formed on the upstream side in the passing direction of the rotating stirring member in the first arc wall curved in an arc shape so as to be recessed toward the developer container, the developer container The developer contained in the portion can be efficiently sent to the supply roller through the first opening even when facing upward.

According to the fourteenth aspect of the present invention, in each developing device, the second arc wall bulges downward, and the second arc wall is provided with a portion at a position lower than the lower end of the second opening. It has been.
Therefore, when the developer stored in the developer container of the developer container is fed upward and reaches the second opening from the first opening, it is supplied without falling and returning to the developer container. Since the roller accumulates in a portion lower than the lower end of the second opening in the second arc wall adjacently disposed, the developer can be efficiently supplied to the supply roller.

1 is a right sectional view of a color printer as an example of an image forming apparatus according to an embodiment of the present disclosure. FIG. 1 shows a state where the unit attachment / detachment opening is opened. FIG. 2 shows a state where the drawer unit is pulled out from the main body casing. FIG. 4 is a right side view of the color printer in the state of FIG. 3. The process cartridge in a state in which both the process shutter and the toner shutter are in the open position is shown, (a) is a right sectional view of the process cartridge, (b) is a right side view of the process cartridge, (c) (B) separately shows the toner box and the process cartridge other than the toner box. The process cartridge in a state where both the process shutter and the toner shutter are in the closed position is shown, (a) is a right sectional view of the process cartridge, (b) is a right side view of the process cartridge, (c) (B) separately shows the toner box and the process cartridge other than the toner box. It is the perspective view which looked at the shutter unit from the right front side. (A) is a perspective view of the toner box with the toner shutter in the closed position as viewed from the left front side, and (b) is a perspective view of the toner box with the toner shutter in the open position as viewed from the left front side. (C) is a perspective view of the toner box with the toner shutter in the closed position as seen from the right front side, and (d) is a perspective view of the toner box with the toner shutter in the open position as seen from the right front side. FIG. 4E is a front sectional view of a main part of the toner box. FIG. 6 is a right side sectional view of the process cartridge in a state where both the process shutter and the toner shutter are in the open position, and shows how the agitator rotates as time elapses from (a) to (d). It is the figure which applied the modification to FIG.8 (d).

1. 1 is a right sectional view of a color printer as an example of an image forming apparatus according to an embodiment of the present invention. FIG. 2 shows a state in which the unit attaching / detaching port is opened in FIG. FIG. 3 shows a state in which the drawer unit in FIG. 2 is pulled out from the main body casing. FIG. 4 is a right side view of the color printer in the state of FIG. For the sake of convenience, FIG. 4 shows one process cartridge that is pulled upward from the drawer unit.

As shown in FIG. 1, the color printer 1 includes a body casing 2 having a box shape that is slightly longer in the vertical direction as an example of the apparatus body. The color printer 1 includes, in the main body casing 2, a paper feed unit 3 that supplies the paper P, an image forming unit 4 that forms an image on the fed paper P, and a paper P on which the image is formed. And a paper discharge unit 5 for discharging the paper.
Note that the orientation of the color printer 1 and the components of the color printer 1 will be described along the illustrated directional arrows unless otherwise noted (the same applies to other drawings). The direction here is defined with reference to a case where a person standing in front of the color printer 1 looks at the color printer 1. In FIG. 1, the left side is the back side of the page, and the right side is the front side of the page. The left-right direction is the same as the width direction. The left-right direction (width direction) and the front-rear direction are included in the horizontal direction.
(1) Paper Feed Unit The paper feed unit 3 includes a paper feed tray 6, a paper supply mechanism 7, and a pair of registration rollers 8.

The paper feed tray 6 is disposed in the horizontal direction and at the bottom of the main body casing 2. The paper feed tray 6 is detachable from the main body casing 2 from the front side. Sheets P are stacked on the sheet feed tray 6.
The paper supply mechanism 7 is provided at the rear end of the paper feed tray 6 and conveys the paper P in the paper feed tray 6 to the image forming unit 4. Specifically, the paper supply mechanism 7 is composed of a known paper supply roller, separation roller, separation pad, paper dust removal roller, paper conveyance path (not labeled), and the like. They are separated one by one and supplied to the upper registration roller 8.

The leading edge of the paper P supplied to the registration roller 8 is aligned by the registration roller 8. Thereafter, the sheet P is conveyed by the registration rollers 8 to the image forming unit 4 (secondary transfer position described later) at a predetermined timing.
(2) Image Forming Unit The image forming unit 4 includes a scanner unit 10, a process unit 11, a transfer unit 12, and a fixing unit 13.
(2-1) Scanner Unit The scanner unit 10 is disposed below the main body casing 2, specifically above the paper feed tray 6, and includes a known laser light emitting unit, a polygon mirror, a plurality of lenses, and a reflecting mirror (reference numeral (Not attached). In the scanner unit 10, a laser is emitted from the laser emission unit based on input of image information from the outside of the color printer 1 or from an image reading unit 35 described later, and the photosensitive unit of the process unit 11 passes through a path indicated by a dashed arrow. Irradiated to a photosensitive drum 19 (described later) as an example of the body.
(2-2) Process Unit The process unit 11 is disposed on the upper side of the scanner unit 10. The process unit 11 includes a drawer (drawer) unit 14.

The drawer unit 14 is detachably attached to the main body casing 2. As will be described later, the attachment / detachment direction of the drawer unit 14 with respect to the main body casing 2 is a direction along the front-rear direction.
The drawer unit 14 includes a hollow box-shaped drawer frame 15 as an example of a support member, and further includes four process cartridges 16 inside the drawer frame 15.

  Almost the entire area of the upper surface of the drawer frame 15 is open and serves as an open portion 15A. The opening 15 </ b> A communicates with the inside of the drawer frame 15 from above. A plurality of through holes 15B are formed in the bottom wall of the drawer frame 15, and laser light emitted from the laser light emitting unit (not shown) of the scanner unit 10 is exposed through the corresponding through hole 15B. The drum 19 (described later) is irradiated. Further, four round holes (exposed holes 15C) are formed in the right side wall of the drawer frame 15 side by side in the front-rear direction (see FIG. 4). These exposure holes 15 </ b> C penetrate the right side wall of the drawer frame 15 in the width direction and communicate with the inside of the drawer frame 15.

  The process cartridge 16 is detachably attached to the drawer frame 15 through the above-described opening portion 15A. The four process cartridges 16 are arranged in parallel along the front-rear direction (substantially horizontal) at substantially equal intervals when viewed from the width direction when mounted on the drawer frame 15, and in the vertical direction (up-down direction). It is slightly inclined to the rear side.

  In the following description of the process cartridge 16 as well, it is assumed that the process cartridge 16 is mounted on the drawer frame 15 and slightly tilted rearward with respect to the vertical direction (vertical direction). Further, since the structure of the process cartridge 16 is the same in the four process cartridges 16, the process cartridge 16 will be described below with reference to the frontmost process cartridge 16 in FIG.

Each process cartridge 16 includes an upper case 17 on the upper side and a lower case 18 on the lower side. Both the upper case 17 and the lower case 18 have a hollow box shape that is long in the width direction. The lower case 18 functions as an example of a housing.
In the upper case 17, a photosensitive drum 19 and a charger 20 are mainly provided.
The central axis 19A of the photosensitive drum 19 extends in the width direction (that is, the axial direction of the photosensitive drum 19 is the width direction), and the photosensitive drum 19 is long in the width direction. Both ends in the width direction of the photosensitive drum 19 are rotatably supported by corresponding side walls on both side walls in the width direction of the upper case 17. Here, the upper surface of the upper case 17 is open, and the upper outer peripheral surface of the photosensitive drum 19 is exposed above the upper case 17 (process cartridge 16) via the opened upper surface of the upper case 17. Furthermore, it is exposed above the drawer frame 15 (drawer unit 14) via the opening 15A of the drawer frame 15. When viewing the four process cartridges 16 together, the four photosensitive drums 19 are arranged in parallel at substantially equal intervals in the front-rear direction (substantially horizontal).

The charger 20 is sandwiched between both side walls in the width direction of the upper case 17. In this state, the charger 20 faces the corresponding photosensitive drum 19 with a gap from the rear lower side.
The lower case 18 is connected to the upper case 17 via a connecting shaft 21 inserted along the width direction at the upper end of the rear side thereof, and is relatively moved with respect to the upper case 17 (specifically, the connecting shaft 21 is a fulcrum). As rocking).

In the lower case 18, a developing roller 22 as an example of a developer carrier, a supply roller 23, and a toner box 24 as an example of a developer container are mainly provided.
The central axes of the developing roller 22 and the supply roller 23 extend along the width direction. Both end portions in the width direction of the developing roller 22 and the supply roller 23 are rotatably supported by corresponding side walls on both side walls in the width direction of the lower case 18.

  The developing roller 22 is disposed at the upper end of the lower case 18. Here, the upper surface of the lower case 18 is open, and the upper outer peripheral surface of the developing roller 22 is exposed above the lower case 18 through the open upper surface of the lower case 18. The lower surface of the upper case 17 described above is also opened, and the upper outer peripheral surface of the developing roller 22 is lower than the lower outer peripheral surface of the photosensitive drum 19 via the lower lower surface of the upper case 17. It faces (in detail, contact) from. More specifically, the entire upper case 17 that supports the developing roller 22 is applied upward toward the upper case 17 that supports the photosensitive drum 19 by a biasing member (not shown) so that the developing roller 22 contacts the photosensitive drum 19. It is energized.

The supply roller 23 is disposed on the lower front side of the developing roller 22 and is in contact with the developing roller 22.
The toner box 24 is disposed in a lower part of the lower case 18 from the supply roller 23 (a box housing chamber 73 described later, see FIG. 5C described later). Specifically, the toner box 24 is detachably attached to the lower case 18 as will be described later. The toner box 24 has a substantially cylindrical shape that is long in the width direction and is hollow, and accommodates toner (developer) of a corresponding color among cyan, magenta, yellow, and black.

Here, a group of the lower case 18 and members (developing roller 22, supply roller 23, toner box 24, etc.) accommodated in the lower case 18 are referred to as a developing device 37. The developing devices 37 are provided as many as the number of the process cartridges 16 (four), and are disposed below the corresponding upper case 17 (in other words, the photosensitive drum 19 provided in the upper case 17).
The drawer unit 14 including the process cartridge 16 and the toner box 24 will be described in detail later.

  In such a process unit 11, the outer peripheral surface of the photosensitive drum 19 is uniformly charged by the charger 20 in each process cartridge 16 during image formation. Then, the laser (see the broken arrow in the figure) from the scanner unit 10 is irradiated to the outer peripheral surface of the charged photosensitive drum 19 through the corresponding passage hole 15B on the bottom wall of the drawer frame 15. As a result, an electrostatic latent image corresponding to an image to be formed on the paper P is formed on the outer peripheral surface of each photosensitive drum 19.

On the other hand, in each process cartridge 16, the toner in the toner box 24 is supplied from below to the supply roller 23 in the developing device 37 (details will be described later). The toner supplied to the supply roller 23 is supplied to the developing roller 22 by the supply roller 23, becomes a thin layer having a predetermined thickness, and is carried on the outer peripheral surface of the developing roller 22.
When the electrostatic latent image formed on the outer peripheral surface of the photosensitive drum 19 is opposed to the developing roller 22 by the rotation of the photosensitive drum 19, the toner carried on the outer peripheral surface of the developing roller 22 is changed to the electrostatic latent image. To be supplied. As a result, the electrostatic latent image is visualized by the toner and becomes a toner image of a predetermined color.

Thus, the developing device 37 functions to develop the electrostatic latent image formed on the corresponding photosensitive drum 19. In each developing device 37, the toner box 24 stores toner for developing the electrostatic latent image on the corresponding photosensitive drum 19.
(2-3) Transfer Unit The transfer unit 12 includes a driven roller 25, a drive roller 26, an intermediate transfer belt 27, a primary transfer roller 28, a secondary transfer roller 29, and a cleaning unit 30.

  The driven roller 25 and the driving roller 26 are arranged to face each other with a space in the front-rear direction, and an endless intermediate transfer belt 27 is stretched between them. In this state, the intermediate transfer belt 27 is adjacent to the drawer unit 14 from above. The driven roller 25 is driven to rotate by the rotational driving of the driving roller 26, and the intermediate transfer belt 27 moves between the driven roller 25 and the driving roller 26.

  Inside the intermediate transfer belt 27, four primary transfer rollers 28 are arranged at intervals in the front-rear direction. Each primary transfer roller 28 is disposed opposite to the corresponding photosensitive drum 19 with the lower portion of the intermediate transfer belt 27 interposed therebetween. A contact position between the photosensitive drum 19 and the intermediate transfer belt 27 is referred to as a primary transfer position. A primary transfer bias is applied to the primary transfer roller 28 from a high-pressure substrate (not shown). As a result, the toner images on the respective photosensitive drums 19 are transferred onto the intermediate transfer belt 27 at the primary transfer position, and the four color toner images transferred from the four photosensitive drums 19 are superimposed on the intermediate transfer belt 27. As a result, a color toner image is formed.

  The driving roller 26 is pressed against the rear side by a secondary transfer roller 29. A contact position between the driving roller 26 and the secondary transfer roller 29 is referred to as a secondary transfer position. A secondary transfer bias is applied to the secondary transfer roller 29 from a high-pressure substrate (not shown). As a result, the color toner image on the intermediate transfer belt 27 is transferred onto the sheet P conveyed upward from the registration roller 8 at the secondary transfer position.

The cleaning unit 30 is disposed above the intermediate transfer belt 27. The cleaning unit 30 collects the toner remaining on the intermediate transfer belt 27 after the transfer of the toner image onto the paper P, and stores the toner therein. The cleaning unit 30 can be replaced by opening the first front cover 31 that is rotatably provided on the front wall of the main casing 2.
(2-4) Fixing Unit The fixing unit 13 is disposed on the downstream side of the transfer unit 12 in the conveyance direction of the paper P, specifically, above the contact position (secondary transfer position) between the driving roller 26 and the secondary transfer roller 29. A known heating roller 32 and pressure roller 33 are provided. The pressure roller 33 is in pressure contact with the heating roller 32. While the paper P passes between the heating roller 32 and the pressure roller 33, the toner image transferred to the paper P is fixed to the paper P by heating and pressing.
(3) Paper Discharge Unit The paper discharge unit 5 has a plurality of conveyance rollers (not denoted by reference numerals), and the sheet P discharged from the fixing unit 13 by these conveyance rollers is transferred to the main casing 2. It is conveyed to a paper discharge tray 34 formed at the top.
(4) Others In the main casing 2, an image reading unit 35 is disposed so as to close the upper side of the paper discharge tray 34. The image reading unit 35 can read a document and read image information of the document. The color printer 1 can also form an image based on the image information read by the image reading unit 35.

Since the color printer 1 can execute both image formation and image reading in this manner, the color printer 1 is configured as a so-called multifunction machine. Further, since the paper P is discharged to the paper discharge tray 34 in the middle of the main body casing 2 (under the image reading unit 35), the color printer 1 is a so-called in-body paper discharge type.
Next, each part of the color printer 1 will be described in detail.
2. Main Body Casing A unit housing chamber 40 for housing the drawer unit 14 is formed inside the main body casing 2. The unit accommodating chamber 40 is a space sandwiched from above and below by the intermediate transfer belt 27 and the scanner unit 10. As shown in FIG. 3, the main casing 2 is provided with a pair of partition walls 41 that partition the unit storage chamber 40 from the left and right. In FIG. 3, the left partition wall 41 of the pair of partition walls 41 is shown.

Guide portions 42 are respectively provided on surfaces of the pair of partition walls 41 facing each other (the right side surface in the case of the left partition wall 41 in FIG. 3).
Referring to FIG. 2 as well as FIG. 3, the guide portion 42 includes, in order from the front side, the first guide roller 43, the first inclined wall 44, the first guide rail 45, the second guide roller 46, the second inclined wall 47, Two guide rails 48 are provided.

The 1st guide roller 43 is rotatably provided in the front-end part of the corresponding division wall 41 (refer FIG. 2).
The 1st guide rail 45 is formed in the plate shape extended flatly in the front-back direction (refer FIG. 3). The front end portion of the first guide rail 45 is adjacent to the first guide roller 43 from the rear side (not shown). The 1st guide rail 45 is arrange | positioned so that it may become the substantially the same position in the up-down direction with the lower part of the 1st guide roller 43 (refer FIG. 2 and FIG. 3).

The first inclined wall 44 has a substantially triangular shape that narrows toward the rear side when viewed from the width direction (see FIG. 2). The first inclined wall 44 has an inclined surface inclined from the upper part of the first guide roller 43 toward the upper surface of the first guide rail 45 (see FIGS. 2 and 3).
As shown in FIG. 3, the second guide roller 46 is rotatably provided at the rear end portion of the corresponding partition wall 41 and is adjacent to the rear end portion of the first guide rail 45 from the rear side. Yes. The upper part of the second guide roller 46 is disposed so as to be substantially at the same position as the first guide rail 45 in the vertical direction.

The second guide rail 48 is formed in a plate shape that extends in the front-rear direction and has a rear end curved upward, and is disposed so as to be substantially in the same position as the lower part of the second guide roller 46 in the vertical direction. ing.
The second inclined wall 47 has a substantially triangular shape that narrows toward the rear side when viewed from the width direction. The second inclined wall 47 has an inclined surface that is inclined from the upper part of the second guide roller 46 toward the upper surface of the second guide rail 48.

As shown in FIG. 1, an attachment / detachment opening (referred to as a unit attachment / detachment opening 49) is formed in the front wall of the main body casing 2. The unit attaching / detaching port 49 communicates with the unit accommodating chamber 40 from the front side (see also FIGS. 2 and 3).
And the 2nd front cover 50 is provided in the front wall of the main body casing 2 so that opening and closing is possible. The second front cover 50 in the closed state shown in FIG. 1 is erected and closes the unit attaching / detaching port 49 from the front. In this state, a rotation shaft 51 extending in the width direction is inserted through the lower end portion of the second front cover 50. The second front cover 50 is connected to the front wall of the main body casing 2 via a rotation shaft 51 and is rotatable about the rotation shaft 51. Therefore, when the second front cover 50 in the closed state is pulled to the front side, the second front cover 50 rotates about the rotation shaft 51 and tilts to the front side (see FIGS. 2 to 4). As a result, the second front cover 50 is opened, and the unit attachment / detachment opening 49 is opened forward (see FIGS. 2 and 3).

  In the main casing 2, a swing unit 52 is provided on the upper portion of the second front cover 50 in a closed state. The swing unit 52 includes a sheet discharge tray 34 and a member below the sheet discharge tray 34 (specifically, the intermediate transfer belt 27, the driven roller 25, the drive roller 26, and the primary transfer roller) in the main casing 2. 28 and the cleaning unit 30). The first front cover 31 described above is also included in the swing unit 52.

Here, in FIG. 1, the front lower end portion of the swing unit 52 is engaged with the upper end portion of the second front cover 50 in the closed state, so that the tilt toward the front side of the second front cover 50 is restricted. The state where the front cover 50 is closed is maintained.
The swing unit 52 can swing up and down around the drive roller 26 of the transfer unit 12 and a swing shaft 53 disposed on the rear side of the paper discharge tray 34.

Therefore, when the swing unit 52 in the state shown in FIG. 1 is swung upward as shown in FIG. 2, the front lower end portion of the swing unit 52 is detached from the upper end portion of the second front cover 50. Thereby, it becomes possible to tilt to the front side of the second front cover 50. Therefore, when the second front cover 50 is tilted forward, the unit attaching / detaching port 49 described above is opened.
3. Drawer Unit (1) Drawer Frame With reference to FIG. 4, the drawer frame 15 has a hollow box shape having an open portion 15A on the upper surface as described above.

  A guide groove 60 extending from the upper end of the inner side surface to the front lower side at the upper end portion of the inner side surface in the width direction (the surface facing the inside of the drawer frame 15) in each of the both side walls in the width direction of the drawer frame 15 is substantially in the front-rear direction. Four are formed at equal intervals. The deepest part (lower end part) of each guide groove 60 is rounded, and therefore each guide groove 60 has a substantially U shape when viewed from the width direction.

Positioning shafts 61 projecting outward in the width direction are integrally provided at the upper ends of the front end portions of both side walls in the width direction of the drawer frame 15. In addition, the upper edge portions of both side walls in the width direction of the drawer frame 15 are bent outward in the width direction to form flanges 62.
As shown in FIG. 3, a protruding piece 63 that protrudes rearward is integrally provided at the upper end of each rear end of each side wall in the width direction of the drawer frame 15. Each protruding piece 63 is provided with two wheels 64 side by side. The rotating shaft of the wheel 64 extends in the width direction and is supported by the protruding piece 63. In this state, the wheel 64 is rotatably supported by the protruding piece 63.

A rotation shaft 65 and a handle 66 are provided on the front wall of the drawer frame 15. The rotation shaft 65 extends along the width direction and is supported by the front wall of the drawer frame 15. In the handle 66, a rotating shaft 65 is inserted into one end portion (rear end portion in FIG. 3). Thereby, the handle 66 is rotatable around the rotation shaft 65 (see FIGS. 1 to 4). The handle 66 is gripped when the drawer unit 14 is attached to and detached from the main body casing 2.
(2) Process Cartridge FIG. 5 shows the process cartridge in a state where both the process shutter and the toner shutter are in the open position, (a) is a right sectional view of the process cartridge, and (b) is the process cartridge. FIG. 7C is a right side view of the toner box, and FIG. 7B shows the toner box and the part other than the toner box in the process cartridge separately.

6A and 6B show the process cartridge in a state where both the process shutter and the toner shutter are in the closed position. FIG. 6A is a right sectional view of the process cartridge, and FIG. 6B is a right side view of the process cartridge. Yes, (c) shows the toner box and the part other than the toner box in the process cartridge separated from each other in (b).
(2-1) Upper Case and Lower Case Referring to FIG. 5A, in the process cartridge 16, as described above, the upper case 17 is a box that is long and hollow in the width direction with the upper and lower surfaces open. It has a shape and supports the photosensitive drum 19 and the charger 20. Here, both ends in the width direction of the shaft of the photosensitive drum 19 (center shaft 19A) protrude outward in the width direction from the side wall on the same side in the width direction in the upper case 17 (see FIG. 5B).

In the upper case 17, a cleaning roller 70 is rotatably provided above the charger 20. The outer peripheral surface of the cleaning roller 70 is in contact with the outer peripheral surface of the photosensitive drum 19 from the rear side. The cleaning roller 70 removes foreign matters such as toner remaining on the outer peripheral surface of the photosensitive drum 19 after the toner image is transferred from the photosensitive drum 19 onto the intermediate transfer belt 27 (see FIG. 1).

As described above, the lower case 18 has a box shape that is long and hollow in the width direction with the upper surface opened. As described above, the lower case 18 can move relative to the upper case 17 connected via the connecting shaft 21. In this case, however, the developing roller 22 of the lower case 18 has a photosensitive drum 19. It shall be fixed in the position which contacted from the front lower side.
When viewed from the width direction, the lower case 18 is similar to a heel that becomes thicker toward the lower side. Accordingly, the inside of the lower case 18 increases in the front-rear direction toward the lower side. The inside of the lower case 18 is partitioned into a developing chamber 71, a supply chamber 72, and a box storage chamber 73 in order from the top.

The developing chamber 71 has a substantially parallelogram shape that is inclined rearward and downward when viewed from the width direction. The developing chamber 71 is exposed upward (outside of the lower case 18) through the open upper surface of the lower case 18.
The supply chamber 72 has a substantially circular shape when viewed from the width direction, and communicates with the developing chamber 71 from the lower front side. A portion of the front wall of the lower case 18 that coincides with the supply chamber 72 bulges out to the front side in an arc shape, and serves as a bulging wall 74. Further, a first projecting wall 75 projecting rearwardly into the lower case 18 with the same curvature as the bulging wall 74 is integrally provided on the front wall of the lower case 18 continuously from the lower end of the bulging wall 74. ing. The first protruding wall 75 functions as an example of a second arc wall, has a substantially U shape that is flattened up and down when viewed from the width direction, and is curved in an arc shape so as to bulge downward. When the swollen wall 74 and the first projecting wall 75 are viewed together, they are substantially C-shaped with the rear side cut out when viewed from the right side. A region inside the substantially C-shaped portion formed by the bulging wall 74 and the first protruding wall 75 is a supply chamber 72.

  The box housing chamber 73 has a substantially circular shape that is at least twice as large as the supply chamber 72 when viewed in the width direction. Specifically, the box housing chamber 73 has a substantially circular shape in which one upper portion on the circumference is recessed inward in an arc shape when viewed from the width direction. In accordance with the box housing chamber 73, the bottom wall of the lower case 18 (including the lower ends of the front wall and the rear wall) bulges out in an arc shape toward the lower side. Further, a second projecting wall 76 that projects from the rear end of the bottom wall of the lower case 18 to the front upper side with the same curvature as the bottom wall is integrally formed on the rear wall of the lower case 18. Is provided. The second protruding wall 76 has an arc shape that protrudes to the front upper side while bulging to the rear upper side as viewed from the width direction. The rear end of the first projecting wall 75 described above is connected to the front (upper) end of the second projecting wall 76. The second projecting wall 76 defines a rear portion of the lower end of the developing chamber 71.

  When the bottom wall of the lower case 18 and the second projecting wall 76 are viewed together, they are substantially C-shaped with the upper side notched when viewed from the right side. In addition, a first protruding wall 75 is disposed. An area surrounded by the bottom wall of the lower case 18, the second projecting wall 76, and the first projecting wall 75 is a box housing chamber 73. FIG. 5A shows the toner box 24 (the toner box 24 and a toner shutter 112 and an agitator 111 described later provided in the toner box 24) housed in the box housing chamber 73.

  Here, in the right side wall of the lower case 18, a portion that coincides with the box housing chamber 73 when viewed from the width direction has a substantially circular through-hole (box attaching / detaching port 84) substantially the same as the box housing chamber 73 viewed from the width direction. The box housing chamber 73 is exposed to the right side through the box attaching / detaching port 84 (see FIG. 5C). Further, in the left side wall of the lower case 18, a portion that coincides with the box storage chamber 73 when viewed from the width direction has substantially the same circular shape as the box storage chamber 73 when viewed from the width direction, and the center of the circle of this portion A coupling gear 85 is rotatably provided at the position (see FIG. 5C).

  As described above, the communication port 77 as an example of the second opening is formed at the rear upper end of the first protruding wall 75 having a substantially U shape (in other words, a tray shape) that is flat in the vertical direction when viewed from the width direction. One is formed. The communication port 77 is elongated in the width direction, penetrates the first projecting wall 75 in the thickness direction, and allows the supply chamber 72 and the box storage chamber 73 to communicate with each other. Specifically, the box housing chamber 73 communicates with the supply chamber 72 from the rear lower side through the communication port 77. And since the communication port 77 is formed in the rear upper end part of the 1st protrusion wall 75, the part (it is called the storage part 75A) in the 1st protrusion wall 75 in a position lower than the lower end of the communication port 77. Is provided.

  In the lower case 18, the developing roller 22 described above is disposed in the developing chamber 71, and the supplying roller 23 described above is disposed in the supply chamber 72. In this state, the lower outer peripheral surface of the supply roller 23 faces the first projecting wall 75 from above and is along the curved upper surface of the first projecting wall 75. On the other hand, the communication port 77 formed in the first projecting wall 75 faces the supply roller 23 from the lower rear side.

  The developing chamber 71 is provided with a layer thickness regulating blade 78. The layer thickness regulating blade 78 is integrally provided with a leaf spring 79 formed in a thin plate shape that is long in the width direction, and a pressure contact rubber 80 provided at the front end of the leaf spring 79. The leaf spring 79 extends from the rear wall of the lower case 18 along the second projecting wall 76 toward the front upper side toward the lower outer peripheral surface of the developing roller 22. A gap between the leaf spring 79 and the second projecting wall 76 is closed by a seal (portion denoted by reference numeral 81). Note that a gap between the front outer peripheral surface of the developing roller 22 and the front wall of the lower case 18 is also closed by a seal (portion denoted by reference numeral 82). The pressure rubber 80 is pressed against the outer peripheral surface of the developing roller 22 from below by the elastic force of the leaf spring 79.

  The lower case 18 is provided with a process shutter 83 as an example of a shutter that opens and closes the communication port 77. The process shutter 83 also functions as an example of the second shutter. The process shutter 83 has a thin plate shape that is long in the width direction, and has a substantially U-shape that is flat in the vertical direction when viewed from the width direction, like the first protruding wall 75. It is arranged along. In this state, the process shutter 83 is slidable in a direction along the curved surface of the curved first protruding wall 75. Note that the toner shutter 112 described above is illustrated immediately below the process shutter 83 in FIG.

In FIG. 5A, the entire process shutter 83 is under the first projecting wall 75, and the process shutter 83 is in an open position shifted from the communication port 77 toward the front lower side. The process shutter 83 in the open position opens the communication port 77.
When the process shutter 83 in the open position slides a predetermined amount along the lower surface of the first projecting wall 75 to the rear upper side, the process shutter 83 reaches the closed position shown in FIG. The process shutter 83 in the closed position closes the entire communication port 77 from the lower rear side.

When the process shutter 83 in the closed position slides by a predetermined amount along the lower surface of the first projecting wall 75, the process shutter 83 returns to the open position shown in FIG.
The lower case 18 is provided with a support member 86 that supports the process shutter 83 and is integrated with the process shutter 83. The support member 86 functions as an example of a rotating member. A group of the process shutter 83 and the support member 86 is referred to as a shutter unit 87.

FIG. 7 is a perspective view of the shutter unit as viewed from the right front side.
Next, each part of the shutter unit 87 will be described with reference to FIG. The description will be made based on the posture of the shutter unit 87 in FIG.
In the process shutter 83, the support member 86 integrally includes a pair of rotating plates 88 connected to both ends in the width direction of the process shutter 83 and a beam member 89 installed between the upper portions of the left and right rotating plates 88. Is prepared.

The left and right rotating plates 88 are substantially circular when viewed from the width direction, and are thin plates in the width direction. An insertion hole 90 is formed at a circular center position in each of the left and right rotating plates 88.
A protrusion (left) protrudes radially outward (downward in FIG. 7) of the rotating plate 88 at one circumferential position on the outer peripheral surface of the left rotating plate 88 (the lower end of the rotating plate 88 in FIG. 7). Projecting portion 91 is provided integrally. The left protruding portion 91 is thin in the width direction like the rotating plate 88 and has a substantially U shape along the lower outer periphery of the rotating plate 88 when viewed from the width direction (see FIG. 5C). On the right side surface of the left protruding portion 91, two concave portions (referred to as a left concave portion 92) that are recessed to the left side are formed side by side along the circumferential direction of the rotating plate 88 (see also FIG. 5C). ).

  On the right side surface of the right rotation plate 88, a protruding portion (referred to as a right protruding portion 93) protruding rightward is integrally provided. The right protrusion 93 has a circular shape with a smaller diameter than the rotating plate 88 when viewed in the width direction, and is thin in the width direction. When viewed from the width direction, the circle center of the right protruding portion 93 and the circle center of the rotating plate 88 coincide with each other. Further, the above-described insertion hole 90 formed in the right rotation plate 88 passes through both the right rotation plate 88 and the right protruding portion 93.

On the outer peripheral edge portion of the right side surface of the right rotating plate 88 (on the rear side of the right protruding portion 93 in FIG. 7) is radially outward of the rotating plate 88 (rear side in FIG. 7). A convex portion 94 that protrudes toward the bottom is integrally provided (see also FIG. 5C). The convex portion 94 projects outward in the radial direction of the rotating plate 88 from the outer peripheral edge of the right side surface of the rotating plate 88 (see also FIG. 5C).
In addition, at the outer peripheral edge of the right side surface of the right rotating plate 88, there are two recesses leftward at a position different from the convex portion 94 in the circumferential direction (a position below the right protruding portion 93 in FIG. 7). A recess (referred to as a right recess 95) is formed side by side along the circumferential direction of the rotating plate 88 (see FIG. 5C).

And in the outer peripheral surface of the right protrusion part 93, in the periphery (periphery of the lower end part of the right protrusion part 93 in FIG. 7) of the part which corresponds to the right recessed part 95 in the circumferential direction of the right protrusion part 93 (or rotation board 88). A rack gear 96 is formed (see also FIG. 5C). The plurality of gear teeth of the rack gear 96 are arranged along the circumferential direction of the right protruding portion 93.
In the process shutter 83 described above, the left end portion is a portion (the lower end portion of the left rotation plate 88 in FIG. 7) where the left protrusion 91 (specifically, the left recess 92) is provided on the left rotation plate 88. The right end portion is connected to a portion where the right concave portion 95 is formed in the right rotation plate 88 (the lower end portion of the right rotation plate 88 in FIG. 7). That is, the process shutter 83 is installed between the lower ends of the left and right rotating plates 88 in FIG. Here, the two right recesses 95 that are recessed to the left at the outer peripheral edge of the right side surface of the right rotating plate 88 cut out the process shutter 83 from the right edge to the left (see FIG. 5C). ). That is, it can be said that the right recess 95 is provided in the process shutter 83. Further, when the left protrusion 91 is regarded as a part of the process shutter 83, it can be said that the left recess 92 of the left protrusion 91 is provided in the process shutter 83. Here, the left recessed portion 92 and the right recessed portion 95 function as an example of a second engaging portion.

The beam member 89 has a plate shape that is long in the width direction, and is provided between the outer peripheral surfaces of the left and right rotating plates 88 at positions different from the process shutter 83 in the circumferential direction of the rotating plate 88. The beam member 89 is curved in an arc shape so as to follow the outer peripheral surfaces of the left and right rotating plates 88 when viewed from the width direction.
The shutter unit 87 having such a configuration is rotatably supported by the lower case 18 as shown in FIG.

Specifically, first, in the shutter unit 87, the left rotation plate 88 is on the left side of the left side surface of the lower case 18 (not shown), and the right rotation plate 88 is on the right side of the right side surface of the lower case 18. It is in. In this state, the left and right rotating plates 88 coincide with the entire supply chamber 72 of the lower case 18 and the front lower side portion of the developing chamber 71 as seen from the width direction (see also FIG. 5A). .
In the shutter unit 87, the process shutter 83 is housed in the box housing chamber 73 of the lower case 18, and the beam member 89 is a front side surface of the lower case 18 (specifically, the front wall of the lower case 18 is expanded). It is located in front of the portion near the exit wall 74 (see also FIG. 5A).

That is, in the shutter unit 87, only the process shutter 83 is in the lower case 18, and portions other than the process shutter 83 are arranged outside the lower case 18 (in other words, the process cartridge 16).
Here, on the outer surface of the both side walls in the width direction of the lower case 18, the width direction outer side is a portion that coincides with the center of curvature of the first protruding wall 75 (see FIG. 5A) as seen from the width direction. A support shaft 97 that protrudes toward the bottom is integrally provided. Each support shaft 97 is inserted from the inner side in the width direction into the insertion hole 90 of the rotation plate 88 on the same side in the width direction in the shutter unit 87.

As a result, the entire shutter unit 87 is rotatable in the clockwise or counterclockwise direction when viewed from the right, with the support shafts 97 on both side walls in the width direction of the lower case 18 as the center. That is, the rotation center of the shutter unit 87 is the support shaft 97 of the lower case 18.
The shutter unit 87 is rotatable within a range in which the process shutter 83 slides between the open position and the closed position described above.

As shown in FIG. 5A, when the process shutter 83 is in the open position, the beam member 89 is in contact with a portion of the front wall of the lower case 18 near the upper end portion of the bulging wall 74 from the front side. The rotation of the shutter unit 87 in the clockwise direction as viewed from the right side is restricted.
With the process shutter 83 in the open position, the shutter unit 87 is rotated counterclockwise as viewed from the right side. Then, as shown in FIG. 6A, when the beam member 89 comes into contact with a portion of the front wall of the lower case 18 near the lower end of the bulging wall 74 from the front upper side, the shutter unit 87 is viewed from the right side. Further, the rotation in the counterclockwise direction is restricted, and the position of the process shutter 83 becomes the closed position.
(2-2) Toner Box In FIG. 8, (a) is a perspective view of the toner box with the toner shutter in the closed position as viewed from the left front side, and (b) is the toner box with the toner shutter in the open position. 2 is a perspective view of the toner box with the toner shutter in the closed position as viewed from the right front side, and FIG. 3D is a perspective view of the toner box with the toner shutter in the open position. Is a perspective view of the toner box as viewed from the right front side, and FIG.

Referring to FIG. 8B, the toner box 24 has a substantially cylindrical shape that is long in the width direction and hollow as described above.
The toner box 24 includes a casing (referred to as a box casing 100) that forms an outer shell thereof. The box casing 100 functions as an example of a developer container.
The box casing 100 has a substantially cylindrical shape that is long and hollow in the width direction. That is, the cross section of the box casing 100 when viewed from the width direction is substantially circular (see FIG. 5A). Both sides of the box casing 100 in the width direction are closed. Toner is accommodated in the box casing 100. The box casing 100 is integrally provided with a peripheral wall 101 that forms an outer peripheral surface thereof, and a pair of side walls 102 that block the peripheral wall 101 from both sides in the width direction.

  A recess is formed in one place (upper end) on the circumference of the peripheral wall 101 so as to be curved in an arc shape toward the circle center side (inside the box casing 100) of the peripheral wall 101 over the entire width direction of the peripheral wall 101 (box casing 100). A curved wall 103 is formed. The curved wall 103 functions as an example of a first arc wall and has a substantially U shape when viewed from the width direction. In other words, as shown in FIG. 5C, the curved wall 103 is outside (upper side) of the box casing 100 in the radial direction (or the radial direction of the agitator shaft 107 described later) centered on the circle center of the peripheral wall 101. The curve is curved in an arc with the reference line X extending in the width direction as the center of curvature. The curvature of the curved wall 103 is substantially the same as the curvature of the first protruding wall 75 described above in the lower case 18 of the process cartridge 16 (see FIG. 5A).

As shown in FIG. 8B, each side wall 102 is the same as the shape of the peripheral wall 101 seen from the width direction, and has a substantially disk shape in which one circumferential portion of the outer peripheral edge is cut out in an arc shape. ing.
The box casing 100 including the peripheral wall 101 and the side wall 102 has a hollow, generally cylindrical shape in which one circumferential portion of the outer peripheral surface is recessed in an arc shape over the entire width direction. Accordingly, the inner space of the box casing 100 has a substantially circular shape with one outer peripheral edge cut out in an arc shape when viewed from the width direction.

Here, one through hole (referred to as a supply port 104) that is long in the width direction is formed at the rear end portion of the outer surface (surface exposed to the outside) of the curved wall 103. The supply port 104 functions as an example of a first opening. The width direction dimension of the supply port 104 is slightly smaller than the width direction dimension of the curved wall 103. The supply port 104 communicates the inside and outside of the box casing 100.
Further, on the outer surface of the curved wall 103, a guide groove (referred to as a right guide groove 105) that is recessed toward the circle center side of the peripheral wall 101 (inside the box casing 100) is formed on the right side of the supply port 104. The right guide groove 105 extends in an arc shape along the direction (circumferential direction) along the curved outer surface of the curved wall 103 when viewed from the width direction. The cross section of the right guide groove 105 viewed from the circumferential direction has a convex shape that narrows toward the outer surface of the curved wall 103. That is, the groove width of the right guide groove 105 is wider on the deepest side than on the outer surface side of the curved wall 103.

In the left side surface of the left side wall 102, a guide groove (referred to as a left guide groove 106) recessed to the right side is formed in a portion along the curved wall 103. The left guide groove 106 extends in an arc shape along the curved wall 103 and has a substantially U shape when viewed in the width direction.
Here, an agitator shaft 107 as an example of a rotation shaft extending in the width direction is provided between a circle center portion of the left side wall 102 and a circle center portion of the right side wall 102. The agitator shaft 107 is rotatably supported by the left and right side walls 102, and the left end portion of the agitator shaft 107 protrudes to the left from the left side surface of the left side wall 102. An input gear 108 that protrudes to the left from the left end of the agitator shaft 107 is integrally provided at the left end of the agitator shaft 107. The input gear 108 functions as an example of a transmission unit.

  As shown in FIG. 5A, in the box casing 100, a support portion 109 that protrudes radially outward of the agitator shaft 107 is integrally provided on the outer peripheral surface of the agitator shaft 107. The support 109 is made of a hard material (hard resin or the like). The support portion 109 is tapered toward the radially outer side of the agitator shaft 107 when viewed from the width direction. A stirring blade 110 as an example of a stirring unit is attached to the support unit 109.

  The stirring blade 110 is made of a flexible material (for example, a film). The stirring blade 110 is supported by the support portion 109 and extends from the support portion 109 to the radially outer side of the agitator shaft 107 (specifically, the inner peripheral surface of the peripheral wall 101 of the box casing 100). Here, the natural length of the stirring blade 110 in the radial direction of the agitator shaft 107 is longer than the distance between the support portion 109 and the inner peripheral surface of the peripheral wall 101. Therefore, the stirring blade 110 is disposed inside the box casing 100 in contact with the inner peripheral surface of the peripheral wall 101 and in a state where the stirring blade 110 is not to some extent. Specifically, as shown in FIG. 5A, when viewed from the right side, in the stirring blade 110, the inner peripheral surface side of the peripheral wall 101 is shifted in the clockwise direction with respect to the support portion 109 side.

  Here, a group of the agitator shaft 107, the support portion 109, and the stirring blade 110 is referred to as an agitator 111 as an example of the stirring member. In the agitator 111, a portion other than the left end portion of the agitator shaft 107 is provided in the toner box 24 (specifically, the box casing 100). The agitator 111 is rotatable around the agitator shaft 107 in a counterclockwise direction when viewed from the right side.

  When the agitator 111 rotates once, the stirring blade 110 passes through the inner peripheral surface of the peripheral wall 101 while contacting the entire area of the inner peripheral surface of the peripheral wall 101 (including the curved wall 103). Since the agitator 111 (stirring blade 110) passes in a counterclockwise direction when viewed from the right side, the supply port 104 formed at the rear end of the curved wall 103 as described above It is formed on the upstream side in the passing direction of the rotating agitator 111.

As shown in FIG. 8B, the toner box 24 is provided with a toner shutter 112 as an example of a shutter. The toner shutter 112 also functions as an example of the first shutter.
The toner shutter 112 has a plate shape that is long in the width direction and is curved in an arc shape with substantially the same curvature as the curved wall 103 of the box casing 100 when viewed from the width direction (see also FIG. 5A). The width direction dimension of the toner shutter 112 is substantially the same as the width direction dimension of the curved wall 103. The dimension of the toner shutter 112 in the circumferential direction (direction along the curved surface) is about half of the circumferential dimension of the curved wall 103.

In the toner shutter 112, a bent portion 113 that is orthogonal to the width direction and is bent in a direction away from the center of curvature of the toner shutter 112 (downward in FIG. 8B) is integrally provided at the left end portion. ing. The bent portion 113 has a thin plate shape in the width direction and is connected to the entire circumferential direction of the left end portion of the toner shutter 112.
On the left side surface of the bent portion 113, two convex portions (referred to as a left convex portion 114) projecting to the left side are integrally provided with an interval in the circumferential direction of the toner shutter 112. A rib (referred to as a left guide rib 115) that protrudes to the right and extends along the circumferential direction of the toner shutter 112 is integrally provided on the right side surface of the bent portion 113.

  In the toner shutter 112, the right end of the outer surface (the surface exposed to the outside in the toner box 24, and the upper surface in FIG. 8B) approaches the center of curvature of the toner shutter 112 (FIG. 8 ( In b), two convex portions (referred to as a right convex portion 116) projecting upward) are integrally provided with a gap in the circumferential direction of the toner shutter 112. The right convex portion 116 and the above-described left convex portion 114 function as an example of a first engaging portion.

  Further, in the toner shutter 112, a rib (referred to as a right guide rib 117) extending along the circumferential direction of the toner shutter 112 is integrated with the right end portion of the back surface (the lower surface in FIG. 8B) of the outer surface described above. (Not shown in FIG. 8B, see FIGS. 8A and 8C). The right guide rib 117 is orthogonal to the width direction and protrudes in a direction away from the center of curvature of the toner shutter 112 (downward in FIG. 8A).

Such a toner shutter 112 is supported by the box casing 100 on the curved wall 103.
Specifically, in the toner shutter 112, the left guide rib 115 fits into the left guide groove 106 of the box casing 100 from the left, and the right guide rib 117 fits into the right guide groove 105 of the box casing 100 from above in FIG. ing. Thus, the toner shutter 112 is supported by the box casing 100 at a plurality of locations in the width direction (the left guide rib 115 and the right guide rib 117).

In this state, the left guide rib 115 is slidable along the circumferential direction of the curved wall 103 along the left guide groove 106, and the right guide rib 117 is aligned along the right guide groove 105 in the circumferential direction of the curved wall 103. It is slidable along.
With reference to the state of FIG. 8A, the lower surface of the toner shutter 112 extends from the upper side (diameter of the box casing 100) over the entire surface in the width direction with respect to the outer surface (upper surface) of the curved wall 103. Facing from the outside in the direction). In this state, the toner shutter 112 is opened along the circumferential direction of the curved wall 103 (see FIGS. 8B and 8D) and closed (see FIGS. 8A and 8). c) and can be slid freely.

When the toner shutter 112 is in the open position, the toner shutter 112 is shifted to the front side with respect to the supply port 104, and the entire region of the supply port 104 is exposed (opened) to the outside (upward) (FIG. 8B). And FIG. 8 (d)).
When the toner shutter 112 is in the closed position, the toner shutter 112 coincides with the supply port 104, and the entire region of the supply port 104 is closed from the outside by the toner shutter 112 (FIGS. 8A and 8C). )reference).

Thus, the toner shutter 112 opens and closes the supply port 104 by moving along the circumferential direction of the curved wall 103.
As shown in FIG. 8D, an operation unit 118 is provided on the right side surface of the right side wall 102 in the toner box 24. The operation unit 118 has a thin plate shape in the width direction, and has a circular shape with a smaller diameter than the side wall 102 when viewed from the right side. As viewed from the width direction, the circle center of the operation unit 118 coincides with the circle center of the right side wall 102 (in other words, the agitator shaft 107, see FIGS. 5A and 5C).

A grip portion 119 is integrally provided on the right side surface of the operation unit 118. The grip portion 119 has an elongated prismatic shape extending linearly, and passes through the center of the circle of the operation portion 118 when viewed from the right side.
A rack gear 120 is formed at one place on the outer peripheral surface of the operation unit 118. 8D, the rack gear 120 is formed at a position slightly shifted counterclockwise from the upper end portion of the grip portion 119 when viewed from the right side with the grip portion 119 extending vertically. The plurality of gear teeth of the rack gear 120 are arranged along the circumferential direction of the operation unit 118.

Such an operation unit 118 is supported by the right side wall 102, and in this state, the operation unit 118 is rotatable around the center of the circle of the operation unit 118.
Here, in relation to the operation unit 118, the right side surface of the right side wall 102 protrudes to the right side at each position sandwiching the curved wall 103 from both sides in the circumferential direction of the substantially circular side wall 102 when viewed from the right side. A cylindrical boss 121 is integrally provided.

  As described above, the rack gear 120 of the operation unit 118 is interposed between the two bosses 121 in the circumferential direction of the side wall 102 (or the operation unit 118) in a state where the operation unit 118 is rotatably supported by the right side wall 102. Has been placed. Therefore, the operation unit 118 has a position where the rack gear 120 abuts on the front boss 121 (referred to as a front position, see FIG. 8D) and a position where the rack gear 120 abuts on the rear boss 121 (referred to as a rear position). , See FIG. 8C). By grasping and twisting the grip portion 119, the operation portion 118 can be rotated.

Here, when viewed from the right side, when the operation unit 118 at the front position is rotated clockwise to the limit, the operation unit 118 reaches the rear position, and the operation unit 118 at the rear position is rotated counterclockwise. When it is rotated to the limit in the direction of, the operation unit 118 returns to the previous position.
When the toner box 24 is viewed as a single unit, the toner shutter 112 and the operation unit 118 are not mechanically connected, and the sliding of the toner shutter 112 and the rotation of the operation unit 118 are independent. Therefore, in the state of the toner box 24 alone, the toner shutter 112 does not slide even if the operation unit 118 is rotated. In the state of the toner box 24 alone, the toner shutter 112 is in the closed position (see FIG. 8C).

  Further, as shown in FIG. 8E, a concave portion (referred to as an accommodation concave portion 122) that is recessed to the right side is formed at one position on the outer peripheral edge of the left side surface of the operation portion 118. A cylindrical claw 123 elongated in the width direction is fitted into 122 from the left side. The right end of the claw 123 and the portion of the operation portion 118 that divides the bottom of the housing recess 122 are connected by a spring 124, and the claw 123 is urged to the left by the spring 124.

  When the operation portion 118 is in the rear position as shown in FIG. 8C, the left end portion of the claw 123 protrudes to the left side from the accommodation recess 122 as shown in FIG. See also)). And the left end part of the nail | claw 123 is hooked from the upstream in the counterclockwise direction seeing from the right side with respect to the part which exists in the vicinity of the rear side boss | hub 121 in the right end part of the outer surface of the curved wall 103. In this state, unless the claw 123 is removed from the curved wall 103, the operation unit 118 cannot be rotated counterclockwise as viewed from the right side.

On the other hand, when the operation unit 118 is in the front position as shown in FIG. 8D, the claw 123 is accommodated while facing the right side surface of the right side wall 102 without being caught by the curved wall 103 as described above. It fits almost completely in the recess 122 (see FIG. 8E) (not shown).
(2-3) Attachment / Removal of Toner Box to / from Process Cartridge Next, attachment / detachment of the toner box 24 to / from the process cartridge 16 (specifically, the developing device 37) will be described.

  First, prior to attaching the toner box 24 to the process cartridge 16, as shown in FIG. 6C, the process shutter 83 is in the closed position in the lower case 18 of the process cartridge 16 (FIG. 6A). See also). On the other hand, in the toner box 24, the toner shutter 112 is in the closed position, and the operation unit 118 is in the rear position (see also FIGS. 8A and 8C).

  Then, the toner box 24 in such a state and having the curved wall 103 positioned at the upper end is placed on the right side of the box attachment / detachment opening 84 on the right side wall of the lower case 18 of the developing device 37 (front side in FIG. 6). ) And then pushed into the left side (the back side in FIG. 6). As a result, the toner box 24 moves to the left side via the box attachment / detachment opening 84 and is accommodated in the box accommodation chamber 73 as shown in FIG. 6B in order from the left part (the input gear 108 side). To go.

When the toner box 24 is completely stored in the box storage chamber 73, the mounting of the toner box 24 to the process cartridge 16 (the lower case 18 of the developing device 37) is completed.
At this time, as shown in FIG. 6A, when viewed from the width direction, the toner box 24 is substantially fit in the box housing chamber 73 and is at a position lower than the supply roller 23. Further, the curved wall 103 of the toner box 24 is disposed so as to face the first protruding wall 75 of the lower case 18 from the lower side, and substantially follows the first protruding wall 75. Further, the upper surface (outer surface) of the toner shutter 112 in the closed position is in contact with the lower surface of the process shutter 83 in the closed position without any gap from the rear lower side. The support shaft 97 of the lower case 18 (the rotation center of the shutter unit 87) and the reference line X (the line extending in the width direction through the center of curvature of the curved wall 103 of the toner box 24) are in the width direction. (See FIG. 6B).

  On the other hand, the right side surface (especially the operation unit 118) of the toner box 24 is exposed to the right side of the lower case 18 through the box attaching / detaching port 84 (see FIG. 6C) (see FIG. 6B). As described above, since the mounting direction of the toner box 24 with respect to the developing device 37 is the direction toward the left side, the operation unit 118 on the right side surface of the toner box 24 has the toner box 24 with respect to the corresponding developing device 37 in the toner box 24. Is provided on the upstream side in the mounting direction. On the other hand, since the input gear 108 (see FIG. 8A) is on the left side surface of the toner box 24, the toner gear 24 is provided on the downstream side in the mounting direction of the toner box 24 with respect to the corresponding developing device 37. ing.

Here, the supply port 104 of the curved wall 103 is opposed to the communication port 77 of the first projecting wall 75 from the lower rear side with the process shutter 83 and the toner shutter 112 in the closed position interposed therebetween. In this state, the supply port 104 and the communication port 77 are not in communication.
Further, the input gear 108 (see FIG. 8A) of the toner box 24 is connected to the coupling gear 85 (see FIG. 6C) on the left side wall of the lower case 18 of the process cartridge 16. Here, in a state where the process cartridge 16 is mounted on the main casing 2, the coupling gear 85 is connected to a drive source (not shown) of the main casing 2. In this case, the input gear 108 is connected to the main body casing 2 via the coupling gear 85 by being connected to the coupling gear 85. Thereby, the input gear 108 can receive a driving force from a driving source (not shown) of the main casing 2 and transmit the driving force to the agitator shaft 107 (in other words, the agitator 111).

  The left convex portion 114 (see FIG. 8A) of the toner shutter 112 corresponds to the left protruding portion 91 on the left rotating plate 88 (see FIG. 7) of the process shutter 83 (specifically, the shutter unit 87). The left recessed portion 92 (see FIG. 6C) is fitted from the right side. Further, the right convex portion 116 (see FIG. 8A) of the toner shutter 112 is fitted into the right concave portion 95 (see FIG. 6C) on the right side of the process shutter 83 from the right side.

That is, in the developing device 37, the left convex portion 114 and the left concave portion 92 engage with each other, and the right convex portion 116 and the right concave portion 95 engage with each other when the toner box 24 is attached to the lower case 18. ing. As a result, the toner shutter 112 and the process shutter 83 are connected.
When the toner box 24 is attached to the corresponding process cartridge 16 (developing device 37), the rack gear 120 of the operation unit 118 of the toner box 24 protrudes to the right of the shutter unit 87 as shown in FIG. It meshes with the rack gear 96 of the portion 93 from below. That is, the operation unit 118 is engaged with the shutter unit 87 of the corresponding developing device 37. Accordingly, the operation unit 118 and the shutter unit 87 (in other words, the process shutter 83) are connected.

Here, as described above, since the toner shutter 112 and the process shutter 83 are connected (see FIG. 6A), the process shutter 83 is opened when the toner box 24 is attached to the process cartridge 16. The operation unit 118 and the toner shutter 112 are connected to each other.
And the nail | claw 123 (refer FIG.8 (e)) of the left side surface of the operation part 118 contacts the part below the right protrusion part 93 in the right side surface of the rotation board 88 of the right side of the shutter unit 87, It is completely contained in the accommodation recess 122 (see FIG. 8E) and is not caught by the curved wall 103 (not shown). Therefore, in this state, the operation unit 118 at the rear position can be rotated in the counterclockwise direction when viewed from the right side.

  Then, with the toner box 24 attached to the process cartridge 16, the operation unit 118 at the rear position is rotated counterclockwise as viewed from the right side. As a result, the shutter unit 87 connected to the operation unit 118 receives the driving force generated by the rotation of the operation unit 118 in the rack gear 96, whereby the support shaft 97 of the lower case 18 (in other words, the reference line described above). Rotate clockwise around X) as seen from the right.

As the shutter unit 87 rotates in the clockwise direction when viewed from the right side, the process shutter 83 of the shutter unit 87 and the toner shutter 112 connected to the process shutter 83 are both viewed from the right side. Rotate (slide) in the direction of rotation.
Then, as shown in FIG. 5B, when the operation unit 118 is rotated to the front position, the process shutter 83 and the toner shutter 112 are rotated to the limit in the clockwise direction when viewed from the right side. ) To each open position as shown in FIG. When both the process shutter 83 and the toner shutter 112 are in the open position, the supply port 104 and the communication port 77 communicate with each other.

  In the state where the operation unit 118 is in the front position as described above, as shown in FIG. 5B, the convex portion 94 provided with the right rotation plate 88 of the shutter unit 87 is formed on the right side wall of the toner box 24. Since the toner box 24 is adjacent to the right side 102 from the right side, the toner box 24 attached to the process cartridge 16 cannot be pulled out (detached) to the right side. Thereby, the state in which the toner box 24 is attached to the process cartridge 16 can be maintained.

  Conversely, when the operation unit 118 at the front position is rotated in the clockwise direction when viewed from the right side, the shutter unit 87 (process shutter 83) and the toner shutter 112 support the lower case 18 when viewed from the right side. The shaft 97 (that is, the reference line X) is rotated (slid) in the counterclockwise direction around the axis 97, and as shown in FIG. Thereby, the supply port 104 and the communication port 77 do not communicate with each other.

  Further, as shown in FIG. 6B, the convex portion 94 of the shutter unit 87 rotates with the rotation of the shutter unit 87 and is shifted upward from the toner box 24 as viewed from the right side. Thereby, even if the toner box 24 is moved to the right side, the toner box 24 is not caught by the convex portion 94, so that the toner box 24 can be detached from the process cartridge 16 as described above.

As described above, the opening / closing operation of the supply port 104 by the toner shutter 112 and the opening / closing operation of the communication port 77 by the process shutter 83 are interlocked.
Here, the image formation described above can be executed when the toner box 24 is attached to the process cartridge 16 and both the process shutter 83 and the toner shutter 112 are in the open position as shown in FIG. .

FIG. 9 is a right sectional view of the process cartridge in a state in which both the process shutter and the toner shutter are in the open position, and shows how the agitator rotates as time elapses from (a) to (d). ing.
As shown in FIG. 9, at the time of image formation, the agitator 111 receives a driving force from the body casing 2 side via an input gear 108 (see FIG. 8A) and a coupling gear 85 (see FIG. 5C). Is transmitted. As a result, the agitator 111 rotates in the counterclockwise direction when viewed from the right side as described above, and stirs the toner (see the portion filled with dots) (note that the rotation locus of the support portion 109 in the agitator 111 is rotated). Is indicated by a dotted line in FIG. 1).

Specifically, in the rotating agitator 111, the toner accumulated in the lower portion of the box casing 100 is reduced to some extent by the stirring blade 110 contacting the inner peripheral surface of the peripheral wall 101 of the box casing 100 as described above. As shown to Fig.9 (a), it is scraped up along a rotation direction.
Then, as the agitator 111 continues to rotate, the toner scraped up by the stirring blade 110 is rotated in the direction of rotation of the agitator 111 (counterclockwise direction when viewed from the right side), as shown in FIG. 9B. It faces the supply port 104 from the upstream side (the rear lower side in FIG. 9B).

Further, when the agitator 111 continues to rotate, the toner facing the supply port 104 as described above is supplied from the upstream side in the rotation direction of the agitator 111 by the stirring blade 110 as shown in FIG. 9C. Is pushed into.
Then, the toner pushed into the supply port 104 is further pushed by the subsequent toner as the subsequent toner is pushed into the supply port 104 by the stirring blade 110 as shown in FIG. 9D. As a result, the toner pushed into the supply port 104 passes through the communication port 77 communicating with the supply port 104 and flows into the supply chamber 72 of the lower case 18 of the process cartridge 16. It accumulates in a portion (reservoir 75A) below the communication port 77 on the upper surface.

When the agitator 111 rotates, in addition to the toner being supplied to the supply chamber 72 as described above, the toner accumulated in the lower portion of the box casing 100 is appropriately stirred.
As described above, the toner accumulated on the upper surface of the first protruding wall 75 in the supply chamber 72 is supplied to the supply roller 23 arranged in the supply chamber 72. Thereafter, the toner is conveyed upward by rotation in the counterclockwise direction when viewed from the right side of the supply roller 23, and is supplied to the developing roller 22 at a contact position between the supply roller 23 and the developing roller 22.

The toner supplied to the developing roller 22 rotates between the pressure contact rubber 80 of the layer thickness regulating blade 78 and the outer peripheral surface of the developing roller 22 as the developing roller 22 rotates counterclockwise as viewed from the right side. Then, while the layer thickness is regulated between them, it is carried as a thin layer on the outer peripheral surface of the developing roller 22 as described above, and then supplied to the photosensitive drum 19.
Here, when the toner accumulates more than necessary on the upper surface of the first projecting wall 75 (reservoir 75A), the excess toner is displaced from the reservoir 75A to the communication port 77, and then the communication port 77 and the supply are supplied. It passes through the mouth 104 in order and returns to the toner box 24. That is, the toner circulates between the toner box 24 and the upper surface of the first protruding wall 75 (reservoir 75A).

  As described above, when both the process shutter 83 and the toner shutter 112 are in the open position, the toner can move between the toner box 24 and the corresponding photosensitive drum 19. However, as shown in FIG. 6A, when both the process shutter 83 and the toner shutter 112 are in the closed position, the supply port 104 and the communication port 77 are closed, so that the toner flows between the toner box 24 and the photosensitive drum 19. Cannot move between.

Thus, the process shutter 83 and the toner shutter 112 allow or restrict the movement of the toner by opening and closing between the toner box 24 and the corresponding photosensitive drum 19. Then, in order to open and close the process shutter 83 and the toner shutter 112, the operation unit 118 (see FIG. 6B) of the toner box 24 is operated.
(3) Attachment / Removal of Process Cartridge (Toner Box) to / from Drawer Frame Next, attachment / detachment of the process cartridge 16 to / from the drawer frame 15 of the drawer unit 14 will be described. Here, it is assumed that the drawer unit 14 is outside the main casing 2.

  Referring to FIG. 4, the process cartridge 16 is disposed above the drawer frame 15. Here, the position of each process cartridge 16 in the drawer frame 15 in the front-rear direction (see FIG. 1) differs depending on the color of the toner stored in the toner box 24 of each process cartridge 16, so that the process cartridge 16 Also above the frame 15, it is arranged at a predetermined position in the front-rear direction.

At this time, corresponding left and right guide grooves 60 are located below the process cartridge 16 in the drawer frame 15.
Then, the process cartridge 16 is lowered and inserted into the drawer frame 15 from the opening portion 15 </ b> A on the upper surface of the drawer frame 15.
When the process cartridge 16 is lowered to some extent, both ends in the width direction of the central shaft 19A of the photosensitive drum 19 of the process cartridge 16 are received in the guide grooves 60 on the same side in the width direction. As a result, the process cartridge 16 advances forward and downward along the direction in which the guide groove 60 extends as the central axis 19 </ b> A of the photosensitive drum 19 is guided by the guide groove 60.

  When the central shaft 19A of the photosensitive drum 19 reaches the deepest portion (lower end) of the guide groove 60 as in the foremost process cartridge 16, the process cartridge 16 stops descending, and the process cartridge 16 with respect to the drawer frame 15 is stopped. Installation is complete. When all the process cartridges 16 are mounted on the drawer frame 15 in the same procedure, the drawer unit 14 is completed. In this state, the drawer frame 15 supports four process cartridges 16 (in other words, the four photosensitive drums 19 and the developing device 37).

When the mounting of the process cartridge 16 to the drawer frame 15 is completed, in the process cartridge 16, the entire right side surface of the toner box 24 is exposed to the right side from the exposure hole 15C at the same position in the front-rear direction on the right wall of the drawer frame 15. Is done.
Therefore, when the gripper 119 of the operation unit 118 of the toner box 24 exposed from the exposure hole 15C is operated in a state where the process cartridge 16 is mounted on the drawer frame 15, as described above, the process shutter 83 and the toner shutter 112 are operated. Can be moved between an open position and a closed position (see FIGS. 5 and 6).

Further, by grasping the grip 119 of the operation unit 118 of the toner box 24 exposed from the exposure hole 15C, the toner box 24 is pulled out to the right side through the exposure hole 15C, and the process cartridge 16 (in other words, the drawer frame 15). ).
Conversely, by inserting the toner box 24 into the exposure hole 15C from the right side, the box accommodation chamber 73 (see FIG. 6C) is inserted through the box attachment / detachment opening 84 (see FIG. 6C) of the corresponding process cartridge 16. ) And the toner box 24 can be mounted on the process cartridge 16 (in other words, the drawer frame 15).

In this way, with the process cartridge 16 mounted on the drawer frame 15, the toner box 24 is moved in the width direction through the exposure hole 15C, and only the toner box 24 is attached to or detached from the drawer unit 14. Can do.
Further, when the process cartridge 16 mounted on the drawer frame 15 is pulled upward and the entire process cartridge 16 is raised above the opening 15A on the upper surface of the drawer frame 15, the separation of the process cartridge 16 from the drawer frame 15 is completed. .
4). Attachment / detachment of drawer unit to / from main body casing Next, attachment / detachment of the drawer unit 14 to / from the main body casing 2 will be described.

First, as shown in FIG. 3, in a state where the drawer unit 14 is not mounted in the main body casing 2, after swinging the swing unit 52 upward, the second front cover 50 is tilted forward, The unit attaching / detaching port 49 described above is opened.
Then, the drawer unit 14 is inserted into the rear unit housing chamber 40 substantially horizontally along the guide portion 42 described above from the opened unit attaching / detaching port 49.

When the drawer unit 14 is inserted into the unit storage chamber 40, the wheel 64 at the rear end of the drawer unit 14 corresponds to the first guide roller 43 (see FIG. 2), rolls on the first inclined wall 44 (see FIG. 2) and the first guide rail 45 and proceeds to the rear side.
When the wheel 64 reaches the first guide rail 45, the flange 62 (see FIG. 4) of the drawer unit 14 is placed on the corresponding first guide roller 43 (see FIG. 2).

Thereby, in the drawer unit 14, the wheel 64 rolls on the first guide rail 45 and advances to the rear side, and the flange 62 (see FIG. 4) is moved by the rolling of the first guide roller 43 (see FIG. 2). By sliding to the rear side, the drawer unit 14 moves to the rear side in a stable posture.
Thereafter, the wheel 64 of the drawer unit 14 rolls on the second guide roller 46, the second inclined wall 47, and the second guide rail 48, and is stopped at the curved rear end of the second guide rail 48. Thus, as shown in FIG. 2, the drawer unit 14 that has been moved in the front-rear direction is positioned by being translated in a diagonally rearward downward direction.

Thereby, the drawer unit 14 is attached to the main casing 2. In this state, in the drawer unit 14, the positioning shaft 61 of the drawer frame 15 is caught on the main body casing 2 (specifically, the partition wall 41), and the drawer unit 14 is also positioned by this.
After that, as shown in FIG. 1, the second front cover 50 is turned upward to be closed, and the swing unit 52 is swung downward to be closed. As a result, the intermediate transfer belt 27 of the transfer unit 12 contacts the photosensitive drums 19 of the drawer unit 14 from above.

When the drawer unit 14 is detached from the main casing 2, as shown in FIG. 2, the unit attaching / detaching port 49 is opened by opening the swing unit 52 and the second front cover 50 in order, and this unit attaching / detaching port is opened. The drawer unit 14 is pulled out from 49 to the front side (see FIG. 3).
As shown in FIG. 4, when the drawer unit 14 is pulled out substantially horizontally until the four exposed holes 15C on the right side wall of the drawer frame 15 are exposed to the right side, the drawer unit 14 is detached from the main body casing 2. Complete. Thus, the drawer unit 14 (drawer frame 15) can be pulled out from the main casing 2 along the front-rear direction (the direction in which the four photosensitive drums 19 shown in FIGS. 1 to 3 are arranged).

In the state where the drawer unit 14 (drawer frame 15) is pulled out from the main body casing 2 as described above, the toner box 24 is inserted into the drawer unit 14 through the corresponding exposure hole 15C of the drawer frame 15 as described above. It can be attached to and detached from the process cartridge 16 (specifically, the developing device 37) supported by the substrate along the width direction.
Further, in this state, by operating the operation unit 118 of each toner box 24, each of the process shutter 83 and the toner shutter 112 can be moved between the open position and the closed position (FIGS. 5 and 6). reference).
5. Operation and Effect (1) As shown in FIG. 1, in this color printer 1, development for developing an electrostatic latent image formed on a corresponding photosensitive drum 19 below a plurality of photosensitive drums 19 arranged in parallel. A plurality of devices 37 are arranged. Each developing device 37 is disposed below the corresponding photosensitive drum 19.

The main body casing 2 of the color printer 1 is provided with a drawer frame 15 that supports the plurality of photosensitive drums 19 and the developing device 37. The drawer frame 15 can be pulled out from the main casing 2 along the arrangement direction of the plurality of photosensitive drums 19 (see FIG. 3).
Each developing device 37 is provided with a toner box 24 that stores toner for developing the electrostatic latent image on the corresponding photosensitive drum 19.

  Referring to FIG. 4, the toner box 24 has an axial direction (width direction) of the photosensitive drum 19 with respect to the developing device 37 supported by the drawer frame 15 in a state where the drawer frame 15 is pulled out from the main body casing 2. It is detachable along. That is, the toner box 24 can be easily attached to and detached from the developing device 37 without the trouble of removing the photosensitive drum 19 above the developing device 37.

As a result, in a configuration in which the plurality of developing devices 37 are disposed below the plurality of photosensitive drums 19 arranged in parallel, it is possible to improve the maintainability of the toner box 24 provided in the developing device 37.
(2) In the color printer 1, the shutter (process shutter 83 and toner shutter 112 shown in FIGS. 5A and 6A) is opened and closed between the toner box 24 and the corresponding photosensitive drum 19. Allow or restrict toner movement.

  In the toner box 24, on the upstream side (right side surface) in the mounting direction of the toner box 24 with respect to the corresponding developing device 37 (which is a direction toward the left side, and may be simply referred to as “mounting direction” hereinafter). An operation unit 118 that is operated to open and close the shutters (process shutter 83 and toner shutter 112) is provided. Therefore, the shutter can be easily opened and closed by operating the operation unit 118 on the upstream side in the mounting direction, which is an easily accessible location in the toner box 24 (see FIGS. 5 and 6). (3) The toner box 24 is provided with an agitator 111 that agitates the toner by transmitting a driving force (see FIG. 5A).

  Further, on the downstream side (left side surface) of the toner box 24 in the mounting direction, there is a main body casing 2 (strictly speaking, a coupling gear 85 provided on the left side wall of the lower case 18 of the developing device 37, see FIG. 6C). ), An input gear 108 that receives a driving force from the main casing 2 and transmits the driving force to the agitator 111 is provided (see FIGS. 8A and 8B).

  Thus, referring to FIG. 6, when the toner box 24 is completely attached to the developing device 37, the input gear 108 is connected to the main casing 2 (strictly, the coupling gear 85, see FIG. 6C). be able to. As a result, the toner box 24 can be attached to the developing device 37 more smoothly than when the input gear 108 is connected to the main casing 2 while the toner box 24 is attached to the developing device 37.

Further, by providing the input gear 108 on the downstream side in the mounting direction in the toner box 24, a space for providing the operation unit 118 on the upstream side in the mounting direction in the toner box 24 can be secured (see FIG. 8A).
(4) As shown in FIG. 9, in the toner box 24, an agitator 111 is provided in a box casing 100 that stores toner. The agitator 111 agitates the toner in the box casing 100 by rotating around an agitator shaft 107 extending along a predetermined direction (width direction).

  Here, the box casing 100 has a curved wall 103. The curved wall 103 enters the box casing 100 with a reference line X extending in the width direction outside the box casing 100 in the radial direction of the agitator shaft 107 (hereinafter, simply referred to as “radial direction”) as the center of curvature. It is curved in an arc shape so as to be recessed (see FIG. 5C). Therefore, the agitator 111 in the box casing 100 can contact (pass through the curved wall 103) the curved wall 103 that is recessed toward the box casing 100 when rotating.

  In the curved wall 103, a supply port 104 that communicates the inside and the outside of the box casing 100 is formed on the upstream side in the passing direction of the rotating agitator 111 (counterclockwise direction when viewed from the right side). Thus, the supply port 104 through which the toner accommodated in the box casing 100 is sent out to the outside of the toner box 24 is arranged on the rotation locus of the agitator 111, and the agitator 111 is rotated with respect to the rotating agitator 111. It can oppose from the downstream of the rotation direction of 111.

As a result, the toner sent in the rotation direction of the agitator 111 by the rotating agitator 111 is efficiently sent to the supply port 104, so that the toner contained in the box casing 100 is efficiently sent out to the outside in the toner box 24. be able to.
(5) Since the toner shutter 112 opens and closes the supply port 104 by moving along the circumferential direction of the curved wall 103 (see FIGS. 8A to 8D), the toner passes through the supply port 104. Can be allowed or regulated as appropriate.
(6) The agitator 111 includes a hard support portion 109 extending radially outward from the agitator shaft 107, and a support blade 109. The agitator 111 extends radially outward from the support portion 109 and has a flexible stirring blade 110. Contains.

In this case, when the agitator 111 rotates, the stirring blade 110 supported by the support unit 109 becomes appropriate, so that a large amount of toner can be sent in the rotation direction of the agitator 111. Further, since the stirring blade 110 is appropriately bent when passing through the curved wall 103 (see FIG. 9D), the stirring blade 110 can be prevented from being caught by the curved wall 103, and the agitator 111 can be smoothly rotated. can do.
(7) Since the cross section of the box casing 100 when viewed from the width direction is substantially circular, it substantially coincides with the rotation locus of the agitator 111. The agitator 111 rotates the toner in the box casing 100 by rotating the agitator 111. Can be sent in the direction without leakage. As a result, the toner can be sent to the supply port 104 more efficiently. The agitator 111 can uniformly agitate the entire toner in the box casing 100.
(8) As shown in FIG. 8, since the toner shutter 112 is supported by the box casing 100 at a plurality of locations in the width direction, the supply port 104 is more stable than when supported at one location. Can be opened and closed.
(9) As shown in FIG. 9, each developing device 37 includes a lower case 18 to which a corresponding toner box 24 is detachably attached.

The lower case 18 is provided with a first projecting wall 75 that is curved in an arc shape along the curved wall 103 of the corresponding toner box 24 and is disposed to face the curved wall 103. That is, the first projecting wall 75 bulges in an arc shape toward the curved wall 103 of the corresponding toner box 24.
In each developing device 37, the developing roller 22 that carries toner to be supplied to the electrostatic latent image formed on the corresponding photosensitive drum 19 by the lower case 18 and the toner in the corresponding toner box 24 are developed by the lower roller 18. And a supply roller 23 to be supplied.

Here, since the supply roller 23 is supported by the lower case 18 such that the outer peripheral surface thereof is along the first protruding wall 75, the supply roller 23 is connected to the inner region of the first protruding wall 75 in each developing device 37. It can be arranged compactly so as to fit. As a result, the entire developing device 37 can be reduced in size (here, in the vertical direction).
(10) In each developing device 37, the first projecting wall 75 is provided with a communication port 77 facing the supply port 104 of the corresponding toner box 24 and facing the supply roller 23, and the process shutter 83 is connected to the communication port. Open and close 77. Therefore, when the process shutter 83 opens the communication port 77 in a state where the supply port 104 of the corresponding toner box 24 is opened, the toner can be moved between the toner box 24 and the supply roller 23 (FIG. 5). (See also (a)). Further, when the process shutter 83 closes the communication port 77, the toner movement between the toner box 24 and the supply roller 23 can be restricted (see FIG. 6A).
(11) A support member 86 is provided in the lower case 18 of each developing device 37 (see also FIG. 7). The support member 86 is rotatable about a reference line X extending in the width direction through the center of curvature of the curved wall 103 of the corresponding toner box 24 (see FIGS. 5B and 6B).

Here, since the process shutter 83 is supported by the support member 86 (see FIG. 7), the process shutter 83 is rotated by a simple operation of rotating the support member 86. At this time, the communication port 77 is rotated. Can be opened and closed (see FIG. 5 (a) and FIG. 6 (a)).
(12) As shown in FIG. 8, each toner box 24 is provided with an operation portion 118 that engages with the support member 86 of the corresponding developing device 37 (FIGS. 5B and 6B). See also). Therefore, by operating the operation unit 118 of each toner box 24, the support member 86 and the process shutter 83 of the corresponding developing device 37 can be easily rotated to open and close the communication port 77 (FIG. 5A). ) And FIG. 6 (a)).
(13) As shown in FIG. 6, in each developing device 37, the left convex portion 114 of the toner shutter 112 and the left concave portion 92 of the process shutter 83 are engaged when the toner box 24 is mounted on the lower case 18. The right convex portion 116 of the toner shutter 112 and the right concave portion 95 of the process shutter 83 are engaged (see also FIG. 6C, FIG. 8A and FIG. 8B). As a result, the opening / closing operation of the supply port 104 by the toner shutter 112 and the opening / closing operation of the communication port 77 by the process shutter 83 are linked, so that the supply port 104 and the communication port 77 can be opened and closed at a time, which is convenient.
(14) As shown in FIG. 9, in each developing device 37, the supply roller 23 is disposed at a position higher than the toner box 24, so the toner in the toner box 24 is conveyed upward and supplied to the supply roller 23. There must be.

However, the toner box 24 in which the supply port 104 is formed on the upstream side in the passing direction of the rotating agitator 111 in the curved wall 103 curved in an arc shape so as to be recessed toward the inside of the box casing 100 is accommodated in the box casing 100. Even when the toner is directed upward, the toner can be efficiently sent to the supply roller 23 through the supply port 104.
(15) In each developing device 37, the first projecting wall 75 bulges downward, and the first projecting wall 75 is provided with a portion (reserving part 75A) located at a position lower than the lower end of the communication port 77. It has been.

Therefore, when the toner accommodated in the box casing 100 of the toner box 24 is sent upward and reaches the communication port 77 from the supply port 104, the toner falls and does not return to the box casing 100, so that the supply roller 23 is adjacent. In the arranged first projecting wall 75, it accumulates in a portion (storage part 75A) lower than the lower end of the communication port 77 (see FIG. 9D). Thereby, the toner can be efficiently supplied to the supply roller 23.
6). Modification FIG. 10 is a diagram in which a modification is applied to FIG.

In the embodiment described above, only one supply port 104 is formed in the curved wall 103 of the toner box 24 (see FIG. 8D), but a plurality of supply ports 104 may be formed as shown in FIG. Good. Accordingly, the above-described communication ports 77 (see FIG. 9) of the process cartridge 16 are also formed in the same number as the supply ports 104.
In FIG. 10, three supply ports 104 are formed so as to be aligned in the width direction, and the supply port 104 in the case where only one of the supply ports 104 is provided in the width direction (FIG. 8D). ))) In the width direction.

In this case, the toner in the toner box 24 (box casing 100) is transferred from the middle supply port 104 of the three supply ports 104 to the process cartridge 77 through the middle communication port 77 of the three communication ports 77. 16 is supplied to the above-described supply chamber 72 (see FIG. 9).
Of the toner supplied to the supply chamber 72, the toner that has not been supplied to the supply roller 23 is out of the two communication ports 77 at both ends in the width direction of the three communication ports 77 and the three supply ports 104. The two supply ports 104 at both ends in the width direction are dropped in this order by their own weight and returned to the toner box 24.

As described above, the toner circulates between the toner box 24 and the supply chamber 72.
Here, in the toner box 24, a seal (not shown) for preventing toner from leaking from the supply port 104 may be provided between the curved wall 103 in which the supply port 104 is formed and the toner shutter 112. is there. The seal is generally provided to rim the supply port 104 (not shown).

  If each of the supply ports 104 is made small by providing a plurality of supply ports 104 as in the modification, the amount of seal (not shown) necessary for fringing the supply ports 104 can be reduced. Accordingly, when the toner shutter 112 is slid, the resistance generated in the toner shutter 112 is reduced by sliding on a seal (not shown), and the toner shutter 112 can be smoothly slid.

  In the above embodiment, as shown in FIG. 1, the intermediate transfer type color printer 1 that temporarily transfers the toner images of the respective colors from the respective photosensitive drums 19 to the intermediate transfer belt 27 and then collectively transfers them onto the paper P is provided. Illustrated. However, the present invention is not limited to the intermediate transfer type color printer, and can also be applied to, for example, a direct transfer type color printer that directly transfers a toner image onto the paper P from each photosensitive drum 19. .

  Further, in this color printer 1, the photosensitive drum 19 is exposed by the laser generated by the scanner unit 10, but the photosensitive drum 19 may be exposed using an LED instead of the scanner unit 10.

DESCRIPTION OF SYMBOLS 1 Color printer 2 Main body casing 15 Drawer frame 18 Lower case 19 Photosensitive drum 22 Developing roller 23 Supply roller 24 Toner box 37 Developing device 75 1st protrusion wall 75A Storage part 77 Communication port 83 Process shutter 86 Support member 92 Left recessed part 95 Right recessed part DESCRIPTION OF SYMBOLS 100 Box casing 103 Curved wall 104 Supply port 107 Agitator shaft 108 Input gear 109 Support part 110 Stirring blade 111 Agitator 112 Toner shutter 114 Left convex part 116 Right convex part 118 Operation part X Reference line

Claims (14)

The device body;
A plurality of photosensitive drums in which electrostatic latent images are formed and arranged in parallel;
A plurality of developing devices provided to be arranged below the corresponding photosensitive drums, and for developing an electrostatic latent image formed on the corresponding photosensitive drums;
A support member provided in the apparatus main body, supporting a plurality of the photosensitive drums and the developing device, and capable of being pulled out from the apparatus main body along an arrangement direction of the plurality of photosensitive drums;
Each developing device includes a developer for developing the corresponding electrostatic latent image on the photosensitive drum, and is supported by the support member in a state where the support member is pulled out from the device main body. A developer container detachable from the developing device along the axial direction of the photosensitive drum,
The developer container is
A developer accommodating portion for accommodating the developer;
A stirring member that is provided in the developer accommodating portion and that stirs the developer by rotating about a rotation axis extending along a predetermined direction;
The developer accommodating portion has a first arc wall that is curved in an arc shape with a reference line extending in the predetermined direction outside the developer accommodating portion in the radial direction of the rotating shaft as a center of curvature.
The image forming apparatus according to claim 1, wherein a first opening that communicates the inside and the outside of the developer accommodating portion is formed on the upstream side in the passing direction of the rotating stirring member in the first arc wall. A shutter that allows or restricts the movement of the developer by opening and closing between the developer container and the corresponding photosensitive drum;
The developer container includes an operation unit provided on an upstream side in a mounting direction of the developer container with respect to the corresponding developing device and operated to open and close the shutter. The image forming apparatus according to claim 1. A stirring member that is provided in the developer container and stirs the developer by transmitting a driving force;
And a transmission unit that is provided on the downstream side in the mounting direction of the developer container and is connected to the apparatus main body so as to receive a driving force from the apparatus main body and transmit the driving force to the stirring member. The image forming apparatus according to claim 2.   The image forming apparatus according to claim 1, further comprising a first shutter that opens and closes the first opening by moving along a circumferential direction of the first arc wall.   The stirring member includes a hard support portion that extends radially outward from the rotating shaft, and a stirring portion that is supported by the support portion, extends outward in the radial direction from the support portion, and has flexibility. The image forming apparatus according to claim 4, wherein:   6. The image forming apparatus according to claim 4, wherein a cross section of the developer accommodating portion when viewed from the predetermined direction is substantially circular.   The image forming apparatus according to claim 4, wherein the first shutter is supported by the developer accommodating portion at a plurality of locations in the predetermined direction. Each of the developing devices
A housing in which the corresponding developer container is detachably mounted;
A second arc wall provided in the housing, curved in an arc shape along the first arc wall of the corresponding developer container, and disposed opposite to the first arc wall;
A developer carrying member supported by the casing and carrying a developer supplied to the electrostatic latent image formed on the corresponding photosensitive drum;
And a supply roller that is supported by the casing so that an outer peripheral surface is along the second arc wall, and that supplies the developer of the corresponding developer container to the developer carrier. An image forming apparatus according to claim 4. In each of the developing devices, the second arc wall is provided with a second opening facing the supply roller and facing the first opening of the corresponding developer container.
The image forming apparatus according to claim 8, wherein each of the developing devices includes a second shutter that opens and closes the second opening. Each of the developing devices includes a rotating member that is provided on the casing and is rotatable about a reference line that extends in the predetermined direction through the center of curvature of the first arc wall of the corresponding developer container. Prepared,
The image forming apparatus according to claim 9, wherein the second shutter is supported by the rotating member.   The image forming apparatus according to claim 10, further comprising an operation unit that is provided in each developer container and engages with the rotation member of the corresponding developing device. The first shutter is provided with a first engagement portion,
The second shutter is provided with a second engagement portion,
In each of the developing devices, the first engaging portion and the second engaging portion are engaged with each other in a state where the developer container is mounted on the housing, and the first shutter The image forming apparatus according to claim 11 , wherein the opening / closing operation of the first opening and the opening / closing operation of the second opening by the second shutter are interlocked.   13. The image forming apparatus according to claim 9, wherein in each of the developing devices, the supply roller is disposed at a position higher than the developer container. In each of the developing devices, the second arc wall bulges downward,
The image forming apparatus according to claim 13, wherein the second arcuate wall is provided with a portion located at a position lower than a lower end of the second opening.