JP6384140B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus employing an electrophotographic system.

  As an image forming apparatus, an intermediate transfer type includes a plurality of photosensitive drums, an intermediate transfer belt to which toner images are transferred from the plurality of photosensitive drums, and a plurality of developing cartridges that supply toner to each of the plurality of photosensitive drums. Color printers are known.

  As such a color printer, a configuration in which a plurality of photosensitive drums are arranged in parallel and brought into contact with the intermediate transfer belt from below is known (for example, see Patent Document 1).

JP 2013-007945 A

  However, in the above-described color printer described in Patent Document 1, the plurality of photosensitive drums are supported by one drum cartridge, and the photosensitive drums are in contact with the intermediate transfer belt from below. When the drum cartridge is pulled out from the apparatus main body during replacement or maintenance, the upper part of the photosensitive drum is exposed.

  If it does so, there exists a possibility that a user may touch a photosensitive drum, and if it touches, an image formation defect may be caused.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image forming apparatus capable of easily removing a drum cartridge from a support while suppressing a user from touching a photosensitive drum.

(1) An image forming apparatus of the present invention includes an apparatus main body, a belt unit having a belt, a photosensitive drum having an axis extending in the first direction, a drum cartridge having a drum frame that supports the photosensitive drum, and a developer. Can be moved in a second direction orthogonal to the first direction between the developing cartridge for storing the cartridge, the inner position in the apparatus main body, and the outer position outside the apparatus main body, and the drum cartridge and the developing cartridge can be attached and detached. The drum cartridge, and the drum cartridge is disposed below the belt unit when the support is positioned at the inner position in a state of supporting the developer cartridge. The developing cartridge is disposed below the drum cartridge, and the drum frame is disposed at one end in the first direction. And it includes a drum grip portion.

  According to such a configuration, by positioning the support at the inner position, the image forming apparatus can be in a state in which image formation is possible with the photosensitive drum facing the belt from below.

  Also, by positioning the support at the outer position, the photosensitive drum can be moved from below the belt, so that the drum cartridge can be detached.

  In the state where the drum cartridge can be detached, the upper portion of the photosensitive drum is exposed by eliminating the belt facing the upper side of the photosensitive drum. However, a drum gripping portion is provided at one end of the drum frame in the first direction. Therefore, the user can easily access the drum cartridge without touching the photosensitive drum, and can exchange the drum cartridge.

  Furthermore, since only the drum cartridge can be detached while the developing cartridge is mounted on the support, the photosensitive drum can be replaced or maintained.

As a result, only the drum cartridge can be easily detached from the support body while suppressing the user from touching the photosensitive drum.
(2) The drum frame may include a pair of drum gripping portions at both ends in the first direction.

  According to such a configuration, the user can reliably recognize the drum gripping portion.

  Therefore, it is possible to further suppress the user from touching the photosensitive drum.

In addition, the user can grip both ends of the drum frame in the first direction as compared with the case where the drum gripping portion is provided only at one end in the first direction. be able to.
(3) Further, the drum gripping portion may overlap the belt when viewed from the first direction in a state where the support is located at the inner position.

  According to such a configuration, the drum gripping portion is arranged to be above the photosensitive drum.

  Therefore, since the user can easily recognize the drum gripping portion when accessing the drum cartridge, the user can securely grip the drum gripping portion instead of the photosensitive drum exposed upward.

As a result, the user can securely grip the drum gripping part without touching the photosensitive drum and detach the drum cartridge from the support.
(4) In addition, the drum gripping part may include a pair of protrusions that are spaced apart from each other in the second direction and a connecting part that connects the pair of protrusions.

According to such a configuration, the user can stably attach / detach the drum cartridge to / from the support body by gripping the connecting portion of the drum gripping portion.
(5) Moreover, the drum holding | gripping part may be provided with the 1st part extended toward upper direction, and the 2nd part extended along a 2nd direction from a 1st part.

According to such a configuration, since the one end of the second portion of the drum gripping portion is open, the user can easily access the second portion.
(6) The support is an exposure member configured to expose the photosensitive drum, and the exposure member disposed below the photosensitive drum with the support supporting the drum cartridge; A covering member configured to move between an exposure position that exposes the exposure member when mounted and a coating position that covers the exposure member when the drum cartridge is detached may be provided.

  According to such a configuration, when the drum cartridge is mounted on the support, since the photosensitive drum faces the exposure member from above, the exposure member can be protected by the photosensitive drum.

  When the drum cartridge is detached from the support, the exposure member can be protected by the covering member instead of the protection by the photosensitive drum.

As a result, the life of the exposure member can be extended.
(7) The support is configured to support a plurality of drum cartridges and developing cartridges, and the plurality of drum cartridges and the plurality of developing cartridges are supported by the support, It may be configured to be arranged in parallel in the second direction.

According to such a configuration, even if each of the plurality of photosensitive drums and each of the plurality of developing cartridges have different usage frequencies, they can be individually replaced or maintenance can be performed.
(8) In the second direction, the dimension between adjacent drum frames may be not less than 0.5 mm and not more than 8 mm.

  According to such a configuration, when the dimension between adjacent drum frames is set to 0.5 mm or more and 8 mm or less, when any drum cartridge is detached from the support, It is possible to prevent the user from putting a hand between the drum frame and the drum frame of the drum cartridge adjacent to the drum frame and trying to remove the drum cartridge.

Therefore, when removing the drum cartridge, the user can recognize the drum gripping portion more reliably.
(9) In the second direction, the drum frames adjacent to each other may be arranged so that their upper surfaces are flush with each other.

  According to such a configuration, no step is formed on the upper surface of the adjacent drum frames, so that the user can easily recognize that there is no gap between the adjacent drum frames.

Therefore, it is possible to further suppress the user from putting a hand between the adjacent drum frames and trying to remove the drum cartridge.
(10) The plurality of drum cartridges may be configured such that the arrangement order in the second direction cannot be changed.

According to such a configuration, when all of the plurality of drum cartridges are detached from the support and are remounted, they can be securely mounted above the corresponding developing cartridge.
(11) The plurality of drum cartridges includes a first drum cartridge and a second drum cartridge adjacent to the first drum cartridge, the first drum cartridge includes a first engagement portion, and the second drum cartridge includes A first engaged portion that can be engaged with the first engaging portion may be provided.

  According to such a configuration, the first drum cartridge and the second drum cartridge can be engaged with each other by a simple configuration in which the first engaging portion and the first engaged portion are engaged.

Therefore, since the pitch between the first drum cartridge and the second drum cartridge can be fixed, the accuracy of the image forming operation can be improved.
(12) Further, the first engaging portion has a convex shape protruding toward the second drum cartridge, and the first engaged portion has a concave shape that can be engaged with the first engaging portion. You may have.

According to such a configuration, since the first engaging portion has a convex shape and the first engaged portion has a concave shape, the first engaging portion and the first engaged portion are Can be easily engaged.
(13) The plurality of drum cartridges further includes a third drum cartridge adjacent to the second drum cartridge, the second drum cartridge includes a second engagement portion, and the third drum cartridge includes the second engagement. A second engaged portion that can be engaged with the first engaging portion, and the second engaged portion and the second engaged portion when viewed from the second direction, The first engaged portion and the position in the first direction may be different.

  According to such a structure, the simple structure that the position in the 1st direction of a 2nd engaging part and a 2nd to-be-engaged part differs from a 1st engaging part and a 1st to-be-engaged part. This makes it impossible to change the arrangement order of the plurality of drum cartridges.

Therefore, each of the plurality of drum cartridges can be securely mounted above the corresponding developing cartridge.
(14) The second engaging portion has a convex shape that protrudes toward the third drum cartridge, and the second engaged portion has a concave shape that can be engaged with the second engaging portion. You may have.

According to such a configuration, since the second engaging portion has a convex shape and the second engaged portion has a concave shape, the second engaging portion and the second engaged portion are Can be easily engaged.
(15) Of the plurality of drum cartridges, the drum cartridge located on the most downstream side in the direction from the inner position toward the outer position includes the third engagement portion, and the support includes the third engaged portion. The third engaging portion and the third engaged portion are different in position in the first direction from the first engaging portion and the first engaged portion when viewed from the second direction. May be.

  According to such a structure, the drum cartridge located in the most downstream in the direction which goes to the outer side position from the inner side position of a support body by simple structure of engaging a 3rd engaging part and a 3rd to-be-engaged part. Can be attached to the support.

The position of the third engaging portion and the third engaged portion in the first direction is different from that of the first engaging portion and the first engaged portion. The drum cartridge located on the most downstream side in the direction from the position toward the outside position can be mounted on the most downstream side in the direction from the inside position of the support to the outside position in the support.
(16) The third engaging portion has a convex shape that protrudes toward the support body, and the third engaged portion has a concave shape that can be engaged with the third engaging portion. It may be.

According to such a configuration, since the third engaging portion has a convex shape and the third engaged portion has a concave shape, the third engaging portion and the third engaged portion are Can be easily engaged.
(17) Further, the support body includes a plurality of drum cartridge housing portions corresponding to each of the plurality of drum cartridges, and the plurality of drum cartridge housing portions includes a plurality of guide portions for guiding the corresponding drum cartridges. The plurality of guide portions may be arranged differently.

According to such a configuration, the arrangement order of the plurality of drum cartridges can be made unchangeable by a simple configuration in which the arrangement of the guide portions of the plurality of drum cartridge housing units is different.
(18) Further, the plurality of drum cartridges and the plurality of developing cartridges may be configured to be detachable upward with respect to the support when the support is located at the outer position.

  According to such a configuration, the plurality of drum cartridges and the plurality of developing cartridges can be individually detached upward with respect to the support located at the outer position.

  At this time, since the developing cartridge is disposed below the drum cartridge, only the drum cartridge can be detached while the developing cartridge is mounted on the support.

In addition, the user can detach the drum cartridge from the support body with a simple configuration of gripping the drum gripping portion and pulling out the drum cartridge upward.
(19) In addition, at least one drum cartridge of the plurality of drum cartridges may include a mounting portion for stacking from above the other drum cartridges of the plurality of drum cartridges.

  According to such a configuration, when one of the plurality of drum cartridges is detached from the support, the detached drum cartridge can be stacked on the other drum cartridge.

Therefore, a space for placing the detached drum cartridge is not required, and space saving can be achieved when the photosensitive drum is replaced or maintained.
(20) The drum gripping part may be engageable with the placing part.

  According to such a configuration, when one drum frame of a plurality of drum frames is stacked on another drum frame, one drum frame is mounted on the drum gripping portion of the other drum frame. Stacking can be done simply by placing the placement part.

Therefore, a plurality of drum cartridges can be easily and reliably stacked.
(21) Of the plurality of drum cartridges, the drum gripping portion of the drum cartridge that is located on the most downstream side in the direction from the inner position toward the outer position is a mounting portion of another drum cartridge among the plurality of drum cartridges. It may be impossible to engage.

  According to such a configuration, the drum cartridges are configured so as not to be stacked with respect to the drum cartridge located on the most downstream side in the direction from the inner position to the outer position of the support.

  Therefore, when the support is located at the outer position, it is possible to suppress the load from being applied to the position farthest from the apparatus main body, and thus it is possible to suppress the apparatus main body from being tilted.

As a result, the apparatus main body can be stabilized even when the support is positioned at the outer position and the drum cartridge is replaced or maintained.
(22) The belt unit may include a positioning unit that positions the plurality of drum cartridges, and the positioning unit may be positioned inward in the first direction with respect to the drum gripping unit.

  According to such a configuration, the belt unit and the plurality of drum frames can be positioned inside the drum gripping portion in the first direction.

  Therefore, it is possible to prevent the positioning portion from being damaged by the drum gripping portion.

  As a result, the plurality of drum frames can be reliably positioned with respect to the belt unit, and the plurality of photosensitive drums can be brought into contact with the belt at a constant pitch.

  In the image forming apparatus of the present invention, the drum cartridge can be easily detached from the support while the user can be prevented from touching the photosensitive drum.

FIG. 1 is a central sectional view showing a printer according to a first embodiment of an image forming apparatus of the present invention. FIG. 2 is a perspective view of the process frame, the developing cartridge, and the drum cartridge shown in FIG. 1 as viewed from the front right side. FIG. 3 is a perspective view showing a state where four developing cartridges are mounted on the process frame shown in FIG. 4A is a partially enlarged view of the LED unit and the cover unit shown in FIG. 3, and shows a state where the cover portion is located at the covering position. 4B is a sectional side view of the LED unit and the cover unit shown in FIG. 4A. FIG. 5A is a partially enlarged view of the LED unit and the cover unit shown in FIG. 3 and shows a state in which the cover part is moving between the covering position and the exposure position. FIG. 5B is a sectional side view of the LED unit and the cover unit shown in FIG. 5A. FIG. 6A is a partially enlarged view of the LED unit and the cover unit shown in FIG. 3, and shows a state where the cover portion is located at the exposure position. 6B is a sectional side view of the LED unit and the cover unit shown in FIG. 6A. FIG. 7A is a perspective view of the drum cartridge shown in FIG. FIG. 7B is a perspective view of the drum cartridge shown in FIG. FIG. 8 is a plan view of the process unit shown in FIG. FIG. 9 is an explanatory diagram for explaining the operation of the swinging portion of the developing cartridge shown in FIG. FIG. 10 is an exploded perspective view of the belt unit shown in FIG. FIG. 11 is a perspective view of the belt unit shown in FIG. FIG. 12 is a side cross-sectional view of the printer shown in FIG. 1, taking a cross section on the left side of the process unit, showing a state where the front cover is located at the closed position and the process frame is located at the inner position. FIG. 13 is a side sectional view showing a positioning state of the belt unit and the process frame in the printer shown in FIG. FIG. 14 is a side cross-sectional view of the printer shown in FIG. 1, taking a cross section on the left side of the process unit, showing a state where the front cover is located at the open position and the process frame is located at the inner position. FIG. 15 is a side cross-sectional view of the printer shown in FIG. 1, taking a cross section on the left side of the process unit, showing a state where the front cover is located at the open position and the process frame is located at the outer position. FIG. 16A is an explanatory diagram for explaining the operation of the cover unit shown in FIG. 3, in which the cover part of the cover unit is positioned at the exposed position by the protrusion of the drum cartridge coming into contact with the biasing part. Indicates. FIG. 16B is an explanatory diagram for explaining the operation of the cover unit following FIG. 16A, and the cover portion of the cover unit is positioned at the covering position by separating the protrusion of the drum cartridge from the urging portion. Indicates the state. FIG. 17A is an explanatory diagram for explaining the operation of the developing gripping portion of the developing cartridge shown in FIG. 2, and shows a state where the swinging portion is located at the accommodation position. FIG. 17B is an explanatory diagram for explaining the operation of the developing gripping portion of the developing cartridge, following FIG. 17A, and shows a state where the swinging portion is located at the protruding position. FIG. 18 is a front view of the process frame, the developing cartridge, and the drum cartridge shown in FIG. FIG. 19 is an explanatory diagram for explaining the attaching and detaching operations of the drum cartridge and the developing cartridge in the printer shown in FIG. 20 is a side sectional view of the two overlapping drum cartridges shown in FIG. FIG. 21A is an explanatory diagram for explaining the operation of the developing slide gripping portion of the developing cartridge in the second embodiment of the present invention, and shows a state where the sliding portion is located at the storage position. FIG. 21B is an explanatory diagram for explaining the operation of the developing slide gripping portion of the developing cartridge, following FIG. 21A, and shows a state where the sliding portion is located at the protruding position. FIG. 22 is a side view of the drum cartridge and the developing cartridge in the third embodiment of the present invention and mounted on the process frame. FIG. 23A is an explanatory diagram for explaining attachment and detachment of a process cartridge according to the fourth embodiment of the present invention, in which the front cover 7 is located at the open position and four process cartridges are mounted in the process cartridge housing portion. Indicates the state. FIG. 23B is an explanatory diagram for explaining the attachment / detachment of the process cartridge following FIG. 23A, in which the front cover 7 is in the open position, and one of the four process cartridges is detached from the process cartridge accommodating portion. Indicates the state.

1. Overall Configuration of Printer As shown in FIG. 1, a printer 1 as an example of an image forming apparatus is a horizontal type intermediate transfer type color printer. In the printer 1, an image is formed in a main body casing 2 as an example of an apparatus main body, a paper feeding unit 3 for feeding paper P, an image forming unit 4 for forming an image on the paper P, and an image. And a paper discharge unit 5 for discharging the paper P.

In the following description, when referring to the direction of the printer 1, the state in which the printer 1 is placed in the horizontal direction is used as a reference. That is, the upper side of the drawing in FIG. 1 is the upper side, and the lower side of the drawing is the lower side. Further, the right side of FIG. 1 is the front, and the left side of FIG. 1 is the rear. In addition, when the printer 1 is viewed from the front, the left and right reference is used. That is, the front side of the page of FIG. 1 is the left side, and the back side of the page is the right side. The left-right direction is an example of the first direction, and the front-rear direction is an example of the second direction. Further, the left is an example of one of the first directions, and the right is an example of the other of the first directions. Further, the front is an example of one in the second direction, and the rear is an example of the other in the second direction.
(1) Main body casing The main body casing 2 has a substantially box shape. The main casing 2 includes a main body opening 6 and a front cover 7.

  The main body opening 6 penetrates the front wall of the main body casing 2 in the front-rear direction.

The front cover 7 has a closed position for closing the main body opening 6 as shown in FIGS. 1 and 12 with the lower end portion as a fulcrum in order to slide the process frame 52 to be described later in and out of the main body casing 2. As shown in FIGS. 14 and 15, it can swing between an open position where the main body opening 6 is opened.
(2) Paper Feed Unit As shown in FIG. 1, the paper feed unit 3 includes a paper feed tray 8, a pickup roller 9, a paper feed roller 10, a paper feed pad 11, a pair of pinch rollers 12, And a pair of registration rollers 13. The pickup roller 9 is configured to convey the paper P on the paper feed tray 8 between the paper feed roller 10 and the paper feed pad 11 by its rotation. The rotation of the paper feed roller 10 causes the paper P to be conveyed one by one, and is conveyed toward the upper pair of registration rollers 13 so that the paper P passes between the pair of pinch rollers 12. Is configured to do. The pair of registration rollers 13 is configured to convey the sheet P between an intermediate transfer belt 41 described later and a secondary transfer roller 38 described later at a predetermined timing by the rotation thereof.
(3) Image Forming Unit The image forming unit 4 includes a process unit 16, a transfer unit 17, and a fixing unit 18.
(3-1) Process Unit The process unit 16 is disposed at the approximate center in the vertical direction of the main body casing 2. The process unit 16 includes a plurality of drum cartridges 21 as an example of four drum units, a plurality of toner cartridges 22 as an example, and a plurality of LED units 23 as an example of four exposure members.

  The four drum cartridges 21 are arranged in parallel at intervals in the front-rear direction in the upper part of the process unit 16. Specifically, a black drum cartridge 21K, a yellow drum cartridge 21Y, a magenta drum cartridge 21M, and a cyan drum cartridge 21C are sequentially arranged from the front to the rear.

  The four drum cartridges 21 support a photosensitive drum 26, a scorotron charger 27, and a drum cleaning roller 28, respectively.

  The photosensitive drum 26 has a substantially cylindrical shape extending in the left-right direction. The photosensitive drum 26 is rotatable about an axis A extending in the left-right direction.

  The scorotron charger 27 is disposed below the photosensitive drum 26 and spaced from the photosensitive drum 26.

  The drum cleaning roller 28 is disposed behind the photosensitive drum 26. The drum cleaning roller 28 is in contact with the rear end portion of the photosensitive drum 26. The drum cleaning roller 28 is configured to clean the surface of the photosensitive drum 26.

  The four developing cartridges 22 are arranged in parallel at intervals in the front-rear direction in the lower part of the process unit 16 and the front lower part of the corresponding photosensitive drum 26, respectively. Specifically, the black developing cartridge 22K, the yellow developing cartridge 22Y, the magenta developing cartridge 22M, and the cyan developing cartridge 22C are sequentially arranged from the front to the rear.

  Each of the four developing cartridges 22 includes a developing roller 30, a supply roller 31, a layer thickness regulating blade 32, and a toner container 33.

  The developing roller 30 is rotatably supported on the rear upper end portion of the developing cartridge 22. The developing roller 30 has a substantially cylindrical shape extending in the left-right direction. The developing roller 30 is in contact with the front lower end portion of the photosensitive drum 26.

  The supply roller 31 is rotatably supported by the developing cartridge 22 at the front lower side of the developing roller 30. The supply roller 31 has a substantially cylindrical shape extending in the left-right direction. The supply roller 31 is in contact with the front lower end portion of the developing roller 30.

  The layer thickness regulating blade 32 is disposed below the developing roller 30. The layer thickness regulating blade 32 is in contact with the lower end portion of the developing roller 30.

  The toner container 33 is disposed below the supply roller 31 and the layer thickness regulating blade 32. The toner storage unit 33 is configured to store toner as an example of a developer.

The four LED units 23 are arranged in parallel at intervals in the front-rear direction at the lower part of the process unit 16 and below the corresponding photosensitive drum 26, respectively. Each of the four LED units 23 exposes the surface of the corresponding photosensitive drum 26 based on predetermined image data.
(3-2) Transfer Unit The transfer unit 17 is disposed above the process unit 16 in the upper part in the main body casing 2. The transfer unit 17 includes a belt unit 37 and a secondary transfer roller 38.

  The belt unit 37 is disposed along the front-rear direction so as to be positioned above all the photosensitive drums 26. The belt unit 37 includes a driving roller 39, a driven roller 40, an intermediate transfer belt 41 as an example of a belt, and a plurality of, that is, four primary transfer rollers.

  The drive roller 39 is rotatably supported at the rear end portion of the transfer unit 17.

  The driven roller 40 is rotatably supported at the front end portion of the transfer unit 17.

  The intermediate transfer belt 41 is stretched around the driving roller 39 and the driven roller 40 so that the lower portion thereof is in contact with the upper end portions of all the photosensitive drums 26. Further, the intermediate transfer belt 41 is moved in a circular motion so that a lower portion thereof is moved from the front to the rear by the driving of the driving roller 39 and the driven of the driven roller 40.

  The four primary transfer rollers 42 are arranged in the front-rear direction so as to be disposed between the driving roller 39 and the driven roller 40 and above the four photosensitive drums 26 via the intermediate transfer belt 41, respectively. They are arranged in parallel at intervals. The primary transfer roller 42 is in contact with the lower portion of the intermediate transfer belt 41 from above.

The secondary transfer roller 38 is disposed behind the drive roller 39 of the belt unit 37 so as to sandwich the intermediate transfer belt 41.
(3-3) Fixing Unit The fixing unit 18 is disposed on the front upper side of the secondary transfer roller 38. The fixing unit 18 includes a heating roller 44 and a pressure roller 45 that presses against the rear upper end of the heating roller 44.
(3-4) Image Forming Operation (3-4-1) Developing Operation When the image forming operation is performed, the supply roller 31 rotates the toner in the toner storage unit 33 by rotating the supply roller 31 and the developing roller. The toner is supplied to the developing roller 30 while being frictionally charged with the toner 30.

  The layer thickness regulating blade 32 regulates the thickness of the toner supplied to the developing roller 30 as the developing roller 30 rotates. As a result, the developing roller 30 carries the toner on the surface thereof as a thin layer having a constant thickness.

On the other hand, the surface of the photosensitive drum 26 is uniformly positively charged by the scorotron charger 27 as the photosensitive drum 26 rotates, and then exposed by the LED unit 23 based on predetermined image data. As a result, the LED unit 23 forms an electrostatic latent image based on the image data on the surface of the photosensitive drum 26. The developing roller 30 supplies the toner carried on the surface thereof to the electrostatic latent image on the surface of the photosensitive drum 26. As a result, the photosensitive drum 26 carries a toner image on the surface thereof.
(3-4-2) Transfer / Fixing Operation The photosensitive drum 26 performs primary transfer of the toner image carried on the surface thereof to the lower part of the intermediate transfer belt 41 sequentially. As a result, the photosensitive drum 26 forms a color image on the surface of the intermediate transfer belt 41.

  The intermediate transfer belt 41 secondarily transfers the color image formed on the surface of the intermediate transfer belt 41 to the paper P supplied from the paper supply unit 3 while passing through the contact position with the secondary transfer roller 38.

The fixing unit 18 heats and presses the paper P while the paper P on which the color image is transferred passes between the heating roller 44 and the pressure roller 45. At this time, the image is thermally fixed on the paper P.
(4) Paper Discharge Unit The paper discharge unit 5 is recessed in a substantially V shape in a side sectional view above the main body casing 2. The paper discharge unit 5 includes a discharge port 47 and a pair of paper discharge rollers 48.

  The discharge port 47 communicates the inside and the outside of the main casing 2 at the front surface at the rear end of the paper discharge unit 5.

  The pair of paper discharge rollers 48 are arranged so as to guide the paper P discharged from the discharge port 47 with the paper P interposed therebetween.

  The upper surface of the main casing 2 in front of the paper discharge unit 5 is defined as a paper discharge tray 49.

The paper discharge roller 48 discharges the paper P, on which the toner image has been thermally fixed in the fixing unit 18, onto the paper discharge tray 49 through the discharge port 47.
2. Details of Process Unit As shown in FIGS. 1 and 2, the process unit 16 includes a process frame 52 as an example of a support.

  As shown in FIGS. 1 and 12, the process frame 52 moves in the front-rear direction between an inner position located in the main casing 2 and an outer position located outside the main casing 2, as shown in FIG. It is configured to be possible. As will be described in detail later, the process frame 52 has a contact position where the four photosensitive drums 26 and the intermediate transfer belt 41 are in contact with each other, as shown in FIG. The four photosensitive drums 26 and the intermediate transfer belt 41 are configured to be movable between separated positions. As shown in FIGS. 1 and 2, the process frame 52 has a substantially frame shape that is substantially rectangular in plan view. The process frame 52 includes a process left side wall 53 as an example of a side plate, a process right side wall 54 as an example of a side plate, a left support wall 55, a right support wall 56, a process front wall 57, and a process rear wall 58. The process bottom wall 59 is provided.

  As shown in FIGS. 2 and 3, the process left side wall 53 and the process right side wall 54 are spaced apart from each other in the left-right direction. The process left side wall 53 and the process right side wall 54 have a substantially plate shape that is substantially rectangular in a side view extending in the front-rear direction.

  The left support wall 55 and the right support wall 56 are adjacently disposed inward in the left-right direction of the process left side wall 53 and the process right side wall 54, respectively. The left support wall 55 and the right support wall 56 have a substantially plate shape that is substantially rectangular in a side view extending in the front-rear direction.

  The left support wall 55 includes a plurality, that is, four bulging portions 62, a plurality, that is, four first drum engagement grooves 70, and a plurality, that is, four second drum engagement grooves 71.

  The right support wall 56 does not include the second drum engagement groove 71 with respect to the left support wall 55, and includes a plurality of, that is, four bulging portions 62, and a plurality, that is, four first drum engagement grooves 70. And.

  The four bulging portions 62 are arranged in parallel at intervals in the front-rear direction. The bulging portion 62 has a substantially plate shape having a substantially rectangular shape in side view that bulges inward in the left-right direction from the lower part of the left support wall 55 and the right support wall 56 in the left-right direction inner surface. The upper surface of the bulging portion 62 is located below the upper surfaces of the left support wall 55 and the right support wall 56 and is defined as a drum cartridge mounting surface 66 for mounting the drum cartridge 21. . The bulging portion 62 includes a first development engagement groove 68 and a second development engagement groove 69.

  The first developing engagement groove 68 is cut out in a substantially rectangular shape in side view from the front end of the drum cartridge mounting surface 66 of the bulging portion 62 downward.

  The second developing engagement groove 69 is a substantially U-shaped groove that is recessed downward from a rear portion of the drum cartridge mounting surface 66 of the bulging portion 62. The vertical dimension of the second development engagement groove 69 is substantially the same as the vertical dimension of the first development engagement groove 68.

  The four first drum engagement grooves 70 are arranged in parallel at intervals in the front-rear direction above each of the four bulging portions 62. The first drum engagement groove 70 is a substantially U-shaped groove that is recessed downward from the upper surfaces of the left support wall 55 and the right support wall 56. The front end edge of the first drum engagement groove 70 coincides with the rear end edge of the first development engagement groove 68 of the corresponding bulging portion 62 in the front-rear direction. Further, the lower end portion of the first drum engagement groove 70 is substantially flush with the drum cartridge mounting surface 66 of the bulging portion 62.

  The four second drum engagement grooves 71 are arranged at intervals in the front-rear direction at the rear of each of the four first drum engagement grooves 70 and each of the four bulging portions 62. Yes. The second drum engagement groove 71 is a substantially U-shaped groove that is recessed downward from the upper surface of the left support wall 55. The vertical dimension of the second drum engagement groove 71 is substantially the same as the vertical dimension of the first drum engagement groove 70.

  As shown in FIGS. 2 and 8, the process front wall 57 is provided between the front end portion of the process left side wall 53 and the front end portion of the process right side wall 54. The process front wall 57 has a substantially plate shape that is substantially rectangular in front view and extends in the left-right direction. The upper end portion of the process front wall 57 extends above the upper end portion of the process left side wall 53 and the upper end portion of the process right side wall 54. The process front wall 57 includes a process refracting portion 74 and a process gripping portion 75.

  The process refraction part 74 has a substantially plate shape that is substantially rectangular in plan view and extends rearward from the upper end edge of the process front wall 57. The process refraction part 74 includes a process recess 76.

  The process concave portion 76 has a concave shape that is recessed in a substantially U shape in plan view from the rear end portion toward the front in the right portion of the process refracting portion 74.

  The process gripping part 75 has a substantially U-shaped substantially prismatic shape in plan view that is opened rearward. The left free end portion of the process gripping portion 75 is fixed to the left portion of the process front wall 57, and the right free end portion of the process gripping portion 75 is fixed to the right portion of the process front wall 57. Has been.

  As shown in FIGS. 3 and 8, the process rear wall 58 is provided between the rear portion of the process left side wall 53 and the rear portion of the process right side wall 54. The process rear wall 58 has a substantially plate shape that is substantially rectangular in front view and extends in the left-right direction.

  As shown in FIGS. 1 and 3, the process bottom wall 59 is constructed between the lower end portion of the process left side wall 53 and the lower end portion of the process right side wall 54. The front end portion of the process bottom wall 59 is continuous with the lower end portion of the process front wall 57, and the rear end portion of the process bottom wall 59 is continuous with the lower end portion of the process rear wall 58. The process bottom wall 59 includes the four LED units 23 and the four cover units 80 described above.

  As shown in FIGS. 1 and 2, the four LED units 23 are arranged behind the four bulging portions 62 and between the left support wall 55 and the right support wall 56, respectively. Yes. As shown in FIGS. 4A and 4B, the LED unit 23 includes an LED array 82, an LED support portion 83, and a body portion 84.

  The LED array 82 has a substantially bar shape extending in the left-right direction. The LED array 82 integrally holds a large number of LEDs arranged in parallel in the left-right direction.

  The LED support portion 83 has a bottomed rectangular frame shape that extends in the left-right direction and is opened upward. The LED support portion 83 receives the LED array 82 so that the upper portion of the LED array 82 is exposed inside.

  The body portion 84 is disposed below the LED support portion 83. The body portion 84 has a substantially plate shape that is substantially rectangular in a front view extending in the left-right direction. The upper end portion of the body portion 84 is continuous with the lower end portion of the LED support portion 83, and the lower end portion of the body portion 84 is embedded in the process bottom wall 59 as shown in FIG.

  As shown in FIGS. 3 and 4A, the four cover units 80 are arranged in parallel at intervals in the front-rear direction so as to cover the LED arrays 82 of the corresponding LED units 23, respectively. 4A and 4B, the cover unit 80 includes a pair of support columns 85, a pair of columnar portions 86, a pair of urging portions 87, and a cover portion 88 as an example of a covering member. It has.

  The pair of support columns 85 extend from the upper surface of the process bottom wall 59 upward along the rear surface of the body portion 84 at both ends in the left-right direction of the LED unit 23, and forward so as to face the upper surface of the LED support portion 83. It has a substantially prismatic shape that bends. Specifically, the support column 85 includes a vertical portion 85A extending in the vertical direction, an inclined portion 85B extending from the upper end portion of the vertical portion 85A toward the front upper side, and a horizontal portion extending forward from the front upper end portion of the inclined portion 85B. 85C. The support column 85 includes a first guide groove 90 and a second guide groove 91.

  The first guide groove 90 penetrates the support column 85 in the left-right direction in the upper part of the vertical portion 85 </ b> A of the support column 85. The first guide groove 90 has a substantially rectangular shape in side view extending in the vertical direction.

  The second guide groove 91 penetrates the support column 85 in the left-right direction from the inclined portion 85B of the support column 85 to the horizontal portion 85C. The second guide groove 91 has a substantially V-shaped side view bent along the inclined portion 85B and the horizontal portion 85C.

  The pair of columnar portions 86 are disposed adjacent to the outer side in the left-right direction of the pair of column portions 85. The cylindrical portion 86 has a substantially cylindrical shape extending upward from the upper surface of the process bottom wall 59. The upper end portion of the cylindrical portion 86 is positioned slightly below the lower end portion of the second guide groove 91.

  Each of the pair of urging portions 87 includes a compression spring 92 and a roller 93.

  The compression spring 92 has a coil shape in which a wire is wound spirally along the vertical direction. The natural length of the urging portion 87 is larger than the vertical dimension of the cylindrical portion 86.

  The roller 93 is connected to the upper end portion of the compression spring 92. The compression spring 92 has a substantially cylindrical shape extending in the left-right direction.

  The urging portion 87 is assembled to the cylindrical portion 86 by inserting the cylindrical portion 86 through the compression spring 92.

  The cover part 88 has a substantially U shape in plan view. Specifically, the cover portion 88 includes a cover main body 94 and a pair of arm portions 95 as an integral unit.

  The cover body 94 has a substantially plate shape that is substantially rectangular in plan view and extends in the left-right direction. The front / rear / left / right dimension of the cover body 94 is slightly larger than the front / rear / left / right dimension of the LED array 82.

  The pair of arm portions 95 are arranged at both ends in the left-right direction of the cover main body 94 and inward in the left-right direction of the pair of support columns 85. The arm part 95 has a substantially prismatic shape that continuously extends from the left and right outer ends of the cover body 94 in the front-rear direction, extends from the rear end part toward the rear lower side, and then refracts downward. . The arm portion 95 includes a first guide shaft 96 and a second guide shaft 97.

  The first guide shaft 96 has a substantially cylindrical shape that extends outward in the left-right direction from the outer surface in the left-right direction at the front upper end of the arm portion 95. The horizontal dimension of the first guide shaft 96 is smaller than the horizontal dimension of the support column 85. The first guide shaft 96 is inserted through the second guide groove 91 of the support column 85.

  The second guide shaft 97 has a substantially cylindrical shape that extends outward in the left-right direction from the left-right outer surface of the rear lower end of the arm portion 95. The horizontal dimension of the second guide shaft 97 is larger than the horizontal dimension of the pair of support columns 85. The second guide shaft 97 is inserted into the first guide groove 90 of the support column 85, and the outer end in the left-right direction is inserted through the roller 93 of the urging unit 87.

  Thereby, in the cover unit 80, the second guide shaft 97 of the cover portion 88 is urged upward by the urging force of the compression spring 92 of the urging portion 87.

  Then, the second guide shaft 97 is positioned at the upper end portion of the first guide groove 90, and the first guide shaft 96 is positioned at the front upper end portion of the second guide groove 91. At this time, the cover main body 94 of the cover portion 88 is located at a covering position facing the LED array 82 from above.

  5A and 5B, when the roller 93 moves downward against the urging force of the compression spring 92, the second guide shaft 97 moves to the approximate center of the second guide groove 91 in the vertical direction. The first guide shaft 96 moves rearward from the front end portion of the first guide groove 90. At this time, the cover main body 94 of the cover portion 88 moves rearward, and the front portion of the LED array 82 is exposed.

  Further, as shown in FIGS. 6A and 6B, when the roller 93 moves downward against the urging force of the compression spring 92, the second guide shaft 97 moves to the lower end of the second guide groove 91, and The one guide shaft 96 moves to a substantially central portion of the first guide groove 90 in the front-rear direction. At this time, the cover main body 94 of the cover portion 88 moves further rearward and moves to an exposure position where the LED array 82 is exposed.

  That is, in the cover unit 80, the cover portion 88 includes a covering position that covers the LED array 82 as shown in FIGS. 4A and 4B, and an exposed position that exposes the LED array 82 as shown in FIGS. 6A and 6B. And is always urged by the pair of urging portions 87 so as to be in the covering position.

  In the process frame 52, as shown in FIGS. 1 and 2, four drum cartridge housing portions 100 and four developing cartridge housing portions 101 are defined.

  The four drum cartridge storage portions 100 are respectively located above the respective drum cartridge placement surfaces 66 of the four bulge portions 62 and from the first drum engagement grooves 70 of the right support wall 56 in a side view. It is defined between the first drum engagement groove 70 and the second drum engagement groove 71 located behind.

  That is, in one drum cartridge housing portion 100, a pair of first drum engagement grooves 70 are disposed on the left and right sides, and one second drum engagement groove 71 is disposed on the left side. The pair of first drum engagement grooves 70 is an example of a pair of drum guides and guide portions. The second drum engagement groove 71 is an example of a guide part.

  The four developing cartridge accommodating portions 101 are respectively in front of the four LED units 23, the four bulging portions 62 of the left supporting wall 55, and the four bulging portions 62 of the right supporting wall 56. It is defined between each other.

  That is, in one developer cartridge housing portion 101, the bulging portion 62 is disposed in a pair of left and right, that is, the first development engagement groove 68 is disposed in a pair in the left and right direction, and the second development engagement groove 69 is disposed in a pair in the left and right direction. Yes. The pair of first development engagement grooves 68 and the pair of second development engagement grooves 69 are an example of a pair of development guides.

The pair of first drum engagement grooves 70 are disposed outward in the left-right direction with respect to the pair of first development engagement grooves 68 and the pair of second development engagement grooves 69.
3. Details of Drum Cartridge (1) Configuration of Drum Cartridge The drum cartridge 21 includes a drum frame 104 as shown in FIG.

  Note that the drum cartridge 21 has almost the same configuration in each of the colors black, yellow, magenta, and cyan, and the configuration is partially different. Therefore, in the following description, the same configuration of the four drum cartridges 21 will be described, and differences between the four drum cartridges 21 will be described each time.

  As shown in FIGS. 7A and 7B, the drum frame 104 includes a drum left side wall 105, a drum right side wall 106, a first connection wall 107, a second connection wall 108, and a charger support 109. Yes.

  The drum left side wall 105 and the drum right side wall 106 are arranged to be spaced from each other in the left-right direction.

  The drum left side wall 105 includes a drum side wall main body 112, a drum refracting portion 114, a placement portion 115, a first drum engaging portion 116, a contact portion 117, and a second drum engaging portion 118. Yes.

  The drum right side wall 106 does not include the second drum engaging portion 118 with respect to the drum left side wall 105, and the drum side wall main body 112, the drum refracting portion 114, the mounting portion 115, and the first drum engaging portion. A portion 116 and a contact portion 117 are provided.

  The drum side wall main body 112 has a substantially plate shape that is substantially rectangular in a side view extending in the up-down and front-back directions. The drum side wall main body 112 includes a drum support portion 120.

  The drum support portion 120 has a substantially cylindrical shape that penetrates substantially the center in a side view of the drum side wall body 112 in a substantially circular shape in a side view and extends outward in the left-right direction from the peripheral portion. The drum support portion 120 of the drum left side wall 105 and the drum support portion 120 of the drum right side wall 106 support the photosensitive drum 26 by inserting both ends of the photosensitive drum 26 in the left-right direction. Note that the upper end portion of the photosensitive drum 26 is exposed between a first connection wall 107 and a second connection wall 108 described later, and is higher than the upper surfaces of the first connection wall 107 and the second connection wall 108. Projects upward.

  The drum refracting portion 114 has a substantially plate shape that is substantially rectangular in plan view and extends inward in the left-right direction from the upper end edge of the drum side wall body 112. The drum refraction part 114 includes a positioning hole 121 as an example of an engagement part.

  The positioning hole 121 passes through the substantially central portion in the front-rear direction of the drum refracting portion 114 in the up-down direction. The positioning hole 121 has a substantially rectangular cross section that is long in the left-right direction. In other words, the positioning hole 121 has a concave shape that is recessed downward from the upper surface of the drum refraction part 114.

  The placement portion 115 is disposed at the lower end portion of the drum side wall main body 112. The mounting portion 115 has a substantially prismatic shape extending in the front-rear direction. The horizontal dimension of the mounting portion 115 is larger than the horizontal dimension of the drum sidewall main body 112. As a result, the mounting portion 115 together with the drum side wall main body 112 has a substantially T shape in front sectional view. In addition, the placement unit 115 includes a receiving groove 122.

  The receiving groove 122 is a groove that is recessed in a substantially rectangular shape in a bottom view from the lower surface of the mounting portion 115 upward.

  The first drum engaging portion 116 has a substantially plate shape that is substantially rectangular in a front view and extends from the front end portion of the drum side wall main body 112 to the front end portion of the mounting portion 115 and protrudes outward in the left-right direction. .

  The abutting portion 117 has a substantially prismatic shape that is substantially rectangular in a front view and protrudes forward from the front surface of the first drum engaging portion 116. The contact part 117 includes a chamfered part 124.

  The chamfered portion 124 is configured such that the lower end portion of the abutting portion 117 at the inner side in the left-right direction is cut away.

  The second drum engaging portion 118 has a substantially prismatic shape protruding leftward from the left surface at the rear end portion of the placement portion 115 of the drum left side wall 105.

  The drum left side wall 105 and the drum right side wall 106 of the yellow drum cartridge 21Y, the magenta drum cartridge 21M, and the cyan drum cartridge 21C each include a drum grip 113, and the black drum cartridge 21K is illustrated in FIG. 19, a left black drum gripping part 134 and a right black drum gripping part 135 are provided.

  As shown in FIG. 7A, the drum gripping part 113 includes a gripping protrusion part 125 as an example of a pair of protrusions and a gripping connection part 126 as an example of a connection part.

  The pair of gripping protrusions 125 are arranged at an interval in the front-rear direction. The grip protrusion 125 has a substantially prismatic shape extending in the vertical direction. The lower ends of the pair of gripping protrusions 125 are fixed to the front upper end and the rear upper end of the drum side wall main body 112, respectively. Further, the upper ends of the pair of gripping protrusions 125 are curved so as to approach each other as they go upward.

  The grip connecting portion 126 has a substantially prismatic shape extending in the left-right direction, and connects between the upper ends of the pair of grip protrusions 125.

  Accordingly, the drum gripping portion 113 has a substantially prismatic shape that is substantially U-shaped when viewed from the side and is opened downward. In addition, the horizontal dimension of the drum gripping portion 113 is slightly smaller than the horizontal dimension of the receiving groove 122 of the mounting portion 115. Further, the drum gripping portion 113 is located outward in the left-right direction with respect to the positioning hole 121.

  As shown in FIG. 19, the left black drum gripping part 134 includes a pair of gripping protrusions 125 and a gripping connection part 126, as with the drum gripping part 113, and is a side surface opened downward. It has a substantially prismatic shape that is generally U-shaped. Further, the left black drum gripping portion 134 includes a flat plate portion 136.

  The flat plate portion 136 has a substantially plate shape in plan view that protrudes leftward over the entire front-rear direction of the grip connecting portion 126 of the left black drum grip portion 134.

  The right black drum gripping part 135 includes a pair of gripping protrusions 125 and a gripping connection part 126, as with the drum gripping part 113, and is substantially U-shaped in a side view that opens downward. It has a prismatic shape. Note that the vertical dimension of the right black drum gripping part 135 is smaller than the vertical dimension of the drum gripping part 113.

  As shown in FIGS. 7A and 7B, the first connecting wall 107 is installed between the upper end portion of the drum side wall body 112 of the drum left side wall 105 and the upper end portion of the drum side wall body 112 of the drum right side wall 106. Yes. The first connecting wall 107 has a substantially plate shape that extends in the front-rear direction and has a front end edge that is refracted downward and is substantially L-shaped in side sectional view. The upper surface of the first connection wall 107 is located below the upper surface of the drum refraction part 114. The front surface of the first connection wall 107 is substantially flush with the front surface of the drum side wall body 112. The first connecting wall 107 includes a ridge 127.

  The protruding portion 127 protrudes forward from the front surface excluding both end portions in the left-right direction of the first connecting wall 107. The ridge 127 has a substantially ridge extending in the left-right direction. The protrusion 127 includes a drum protrusion 128.

  The drum convex portion 128 has a convex shape with a substantially rectangular cross section that protrudes forward from the front surface of the ridge portion 127.

  In addition, as shown in FIG. 8, the arrangement | positioning in the left-right direction differs in the drum convex part 128 by each of the four drum cartridges 21. As FIG. Specifically, the drum convex portion 128 of the black drum cartridge 21K is the black drum convex portion 128K, the drum convex portion 128 of the yellow drum cartridge 21Y is the yellow drum convex portion 128Y, and the drum convex portion 128 of the magenta drum cartridge 21M is the magenta drum convex portion. The drum convex portion 128 of the portion 128M and the cyan drum cartridge 21C is referred to as a cyan drum convex portion 128C, and each will be described.

  The black drum convex portion 128 </ b> K is disposed on the right side portion of the protruding portion 127.

  The yellow drum convex portion 128Y is disposed slightly to the right of the substantially central portion in the left-right direction of the protrusion 127 and to the left of the black drum convex portion 128K.

  The magenta drum convex portion 128M is disposed slightly to the left of the substantially central portion in the left-right direction of the ridge portion 127 and to the left of the yellow drum convex portion 128Y.

  The cyan drum convex portion 128 </ b> C is a left portion of the ridge portion 127 and is disposed on the left side of the magenta drum convex portion 128 </ b> M.

  7A and 7B, the second connecting wall 108 is installed between the rear upper end portion of the drum side wall main body 112 of the drum left side wall 105 and the rear upper end portion of the drum side wall main body 112 of the drum right side wall 106. Has been. The second connecting wall 108 has a substantially prismatic shape extending in the left-right direction. The second connection wall 108 includes a drum recess 130.

  The drum recess 130 has a concave shape that is recessed in a substantially U shape in plan view from the rear surface of the second connecting wall 108 to the front.

  In addition, as shown in FIG. 8, the arrangement | positioning in the left-right direction and a structure differ mutually with the drum recessed part 130, as shown in FIG. Specifically, the drum recess 130 of the black drum cartridge 21K is a black drum recess 130K, the drum recess 130 of the yellow drum cartridge 21Y is a yellow drum recess 130Y, and the drum recess 130 of the magenta drum cartridge 21M is a magenta drum recess 130M. explain. Further, the cyan drum cartridge 21C does not include the drum recess 130.

  The black drum recess 130 </ b> K is disposed slightly to the right of the substantially central portion in the left-right direction of the second connecting wall 108.

  The yellow drum recess 130Y is disposed slightly to the left of the substantially central portion in the left-right direction of the second connecting wall 108 and to the left of the black drum recess 130K.

  The magenta drum concave portion 130M is a left portion of the second connecting wall 108 and is arranged to the left of the yellow drum concave portion 130Y.

  As shown in FIGS. 7B and 16B, the charger support portion 109 is located below the second connecting wall 108, the rear lower end portion of the drum side wall body 112 of the drum left side wall 105, and the drum side wall of the drum right side wall 106. It is installed between the rear lower end portion of the main body 112. The charger support portion 109 has a substantially frame shape that is substantially U-shaped in cross-section and extends in the left-right direction and is opened toward the front upper side. The charger support 109 has the scorotron charger 27 described above. In addition, the charger support unit 109 includes a pair of extending portions 132.

The pair of extending portions 132 are disposed at both left and right end portions of the charger support portion 109. The extending portion 132 has a substantially prismatic shape protruding downward from the front lower surface of the charger support portion 109.
(2) Mounting state and arrangement order of drum cartridges on process frame Each of the four drum cartridges 21 is housed in a corresponding drum cartridge housing portion 100 of the process frame 52 as shown in FIGS. Sometimes, on the left side, the first drum engaging portion 116 is fitted into the first drum engaging groove 70 from above, and the second drum engaging portion 118 is fitted into the second drum engaging groove 71 from above. waiting. Further, on the right side, the first drum engaging portion 116 is fitted into the first drum engaging groove 70 from above.

  As a result, the left placement portion 115 is placed on the drum cartridge placement surface 66 of the left bulge portion 62, and the right placement portion 115 is placed on the drum cartridge placement of the right bulge portion 62. The drum cartridge 21 is placed on the placement surface 66 and is housed in the drum cartridge housing portion 100.

  At this time, as shown in FIG. 16A, the extending portion 132 of the drum cartridge 21 is in contact with the upper end portion of the roller 93 of the cover unit 80, and the roller 93 is moved against the urging force of the compression spring 92. Pressing downward.

  As a result, as shown in FIGS. 6A and 6B, the cover 88 is positioned at the exposed position, and the LED unit 23 and the photosensitive drum 26 face each other in the vertical direction.

  As shown in FIG. 8, when the four drum cartridges 21 are housed in the corresponding drum cartridge housing portions 100 of the process frame 52, the arrangement order in the front-rear direction cannot be changed.

  Specifically, the process recess 76 of the process frame 52 and the respective drum recesses 130 of the three drum cartridges 21 other than the cyan drum cartridge 21C are arranged at different positions in the left-right direction, and the four drum cartridges 21 are arranged. The drum protrusions 128 are arranged at different positions in the left-right direction.

  Thus, the black drum cartridge 21K is accommodated in the foremost drum cartridge accommodating portion 100 such that the black drum convex portion 128K is engaged with the process concave portion 76 of the process frame 52.

  Further, the yellow drum cartridge 21Y is accommodated in the second drum cartridge accommodating portion 100 from the front so that the yellow drum convex portion 128Y engages with the black drum concave portion 130K of the black drum cartridge 21K.

  Further, the magenta drum cartridge 21M is accommodated in the second drum cartridge accommodating portion 100 from the rear so that the magenta drum convex portion 128M engages with the yellow drum concave portion 130Y of the yellow drum cartridge 21Y.

  Further, the cyan drum cartridge 21C is accommodated in the rearmost drum cartridge accommodating portion 100 such that the cyan drum convex portion 128C engages with the magenta drum concave portion 130M of the magenta drum cartridge 21M.

  Thus, the four drum cartridges 21 are arranged in parallel along the front-rear direction so that there is no substantial gap. Specifically, the dimension between the drum frames 104 adjacent in the front-rear direction is, for example, 0.5 mm or more, preferably 2 mm or more, for example, 8 mm or less, preferably 5 mm or less.

  At this time, as shown in FIG. 1, the upper surface of the first connecting wall 107 of the black drum cartridge 21 </ b> K and the upper surface of the process refraction part 74 of the process frame 52 are flush with each other.

  Of the adjacent drum cartridges 21, the second connecting wall 108 of the front drum cartridge 21 and the first connecting wall 107 of the rear drum cartridge 21 are flush with each other.

  As shown in FIG. 8, among the four drum cartridges 21, the cyan drum cartridge 21C is an example of the first drum cartridge, and the magenta drum cartridge 21M adjacent to the cyan drum cartridge 21C is an example of the second drum cartridge. The yellow drum cartridge 21Y adjacent to the magenta drum cartridge 21M is an example of the third drum cartridge.

  The cyan drum convex portion 128C of the cyan drum cartridge 21C is an example of a first engaging portion, and the magenta drum concave portion 130M of the magenta drum cartridge 21M that engages with the cyan drum convex portion 128C is an example of a first engaged portion. It is.

  The magenta drum convex portion 128M of the magenta drum cartridge 21M is an example of the second engaging portion, and the yellow drum concave portion 130Y of the yellow drum cartridge 21Y that engages with the magenta drum convex portion 128M is an example of the second engaged portion. It is.

  The magenta drum convex portion 128M and the yellow drum concave portion 130Y are different from the cyan drum convex portion 128C and the magenta drum concave portion 130M in the left-right direction.

  Of the four drum cartridges 21, the black drum convex portion 128K in the most downstream black drum 21K in the direction in which the process frame 52 is directed from the inner position toward the outer position is an example of the third engagement portion. The process recess 76 of the process frame 52 that engages with the black drum protrusion 128K is an example of a third engaged portion.

The black drum convex portion 128K and the process concave portion 76 are different from the cyan drum convex portion 128C and the magenta drum concave portion 130M in the left-right direction.
4). Details of Developing Cartridge (1) Configuration of Developing Cartridge As shown in FIGS. 2 and 9, the developing cartridge 22 includes a developing frame 140 and a bearing member 141.

  The developing frame 140 has a substantially rectangular tube shape that extends in the left-right direction and whose left end and right end are closed. Note that the rear upper end portion of the developing frame 140 is communicated in the left and right directions so that the rear upper end portion of the developing roller 30 is exposed. Further, a lower portion of the developing frame 140 is defined as a toner containing portion 33. The development frame 140 includes a pair of development grips 143.

  The pair of development grips 143 are disposed at both left and right ends of the development frame 140. The development gripping part 143 includes a base part 144, a swinging part 145 as an example of a moving part, and a torsion spring 146 as an example of an urging member.

  The base portion 144 has a substantially prismatic shape that is substantially L-shaped when viewed from the front, extending upward from both ends in the left-right direction on the upper surface of the developing frame 140 and then extending outward in the left-right direction. As shown in FIG. 8, the dimension between the right end portion of the left base portion 144 and the left end portion of the right base portion 144 is larger than the horizontal dimension of the protrusion 127 of the drum cartridge 21. Slightly bigger. The dimension between the left end of the left base portion 144 and the right end portion of the right base portion 144 is such that the right surface of the left contact portion 117 and the left surface of the right contact portion 117 are Are approximately the same as those between. As shown in FIG. 9, the base portion 144 includes a receiving portion 147 and a shaft portion 148.

  The receiving portion 147 is recessed in a substantially rectangular shape in the rear view from the rear to the front at the outer end in the left-right direction of the base portion 144.

  The shaft portion 148 has a substantially cylindrical shape that protrudes rearward from the front surface of the receiving portion 147. The rear end portion of the shaft portion 148 is located at substantially the same position as the rear end portion of the base portion 144 in the front-rear direction.

  The oscillating portion 145 has a long and substantially rectangular tube shape with one end closed. The swing part 145 includes a through hole 149.

  The through hole 149 penetrates the other end portion of the swinging portion 145 in a substantially circular shape when viewed from the back.

  When the through hole 149 receives the shaft portion 148, the swinging portion 145 extends outward in the left-right direction with the shaft portion 148 as a fulcrum, and protrudes so that the tip is relatively separated from the developing frame 140. 9 extends downward with the shaft portion 148 as a fulcrum, and the vertical direction so that the distance between the tip and the developing frame 140 is smaller than the protruding position and is relatively close to the developing frame 140. 9 is attached so as to be rotatable between the housing position indicated by a virtual line in FIG.

  As shown in FIG. 18, when the swinging portion 145 is located at the protruding position, the dimension between the left end portion of the left swinging portion 145 and the right end portion of the right swinging portion 145 is It is larger than the horizontal dimension of the process frame 52.

  Further, when the swinging portion 145 is located at the protruding position, it is disposed above the process left side wall 53 and the process right side wall 54 and viewed from above, the process left side wall 53 and the process right side wall 54 overlapping.

  As shown in FIG. 9, the torsion spring 146 has a coil shape in which the wire is wound spirally along the front-rear direction. Then, the shaft portion 148 is inserted into the torsion spring 146 in the swinging portion 145, so that one end portion of the wire rod of the torsion spring 146 comes into contact with the upper surface of the receiving portion 147 from below, and other torsion springs 146 are provided. The end portion is in contact with the inner surface of the swinging portion 145 from below. Thereby, the torsion spring 146 urges the swinging portion 145 from the accommodation position toward the protruding position.

  As shown in FIGS. 2 and 9, the bearing member 141 is disposed on the right side of the developing frame 140. The bearing member 141 has a substantially thick plate shape extending in the up-down and front-back directions. The bearing member 141 includes a first development engagement portion 151 and a second development engagement portion 152.

  The first developing engagement portion 151 protrudes rightward from the front lower end portion of the bearing member 141. The first developing engagement portion 151 has a substantially plate shape that is substantially U-shaped in a side view. Further, the upper surface of the first developing engagement portion 151 is inclined downward as it goes rightward.

  The second developing engagement portion 152 has a substantially prismatic shape protruding rightward from the rear lower end portion of the bearing member 141. The upper surface of the second developing engagement portion 152 is inclined downward as it goes rightward.

  The left side of the developing frame 140 includes a first developing engagement portion 151 that is symmetric with respect to the substantially central portion of the developing cartridge 22 in plan view, and a second developing engagement portion 152 that is not shown, but is not shown. It has.

In other words, the developing cartridge 22 includes a pair of the first developing engagement portion 151 and the second developing engagement portion 152.
(2) Mounting state of developer cartridge to process frame As shown in FIGS. 2 and 3, each of the four developer cartridges 22 is paired with a pair of developer cartridge accommodating portions 101 of the process frame 52. The first development engagement portion 151 is fitted into the pair of first development engagement grooves 68 from above, and the pair of second development engagement portions 152 is engaged with the pair of second development engagement grooves 69. It is fitted from above.

  As a result, the developing cartridge 22 is supported by the left bulging portion 62 and the right bulging portion 62 and is housed in the developing cartridge housing portion 101.

  In a state where both the developing cartridge 22 and the drum cartridge 21 are mounted on the process frame 52, as shown in FIG. 17A, the developing cartridge 22 is disposed below the drum cartridge 21, and the developing cartridge The abutting portion 117 of the drum cartridge 21 abuts against the swinging portion 145 of the 22 developing gripping portion 143.

As a result, in the pair of developing grips 143, the swinging part 145 is positioned at the accommodation position against the urging force of the torsion spring 146.
5). Details of Belt Unit As shown in FIGS. 10 and 11, the belt unit 37 includes a belt frame 155 and four pairs of brackets 166.

  The belt frame 155 includes a belt left side wall 156, a belt right side wall 157, and a belt frame main body 158 as an integral unit.

  The belt left side wall 156 and the belt right side wall 157 are arranged at intervals in the left-right direction. The belt left side wall 156 and the belt right side wall 157 have a substantially plate shape that is substantially rectangular in a side view extending in the front-rear direction. Each of the belt left side wall 156 and the belt right side wall 157 includes a positioning protrusion 160 as an example of four positioning portions.

  The four positioning protrusions 160 are arranged in parallel at intervals in the front-rear direction. The positioning protrusion 160 has a convex shape with a substantially rectangular cross section that protrudes downward from the lower surface of the belt left side wall 156 and the belt right side wall 157. In other words, four pairs of positioning protrusions 160 are arranged in the belt frame 155. Further, the four pairs of positioning protrusions 160 are positioned inward in the left-right direction with respect to the pair of drum gripping portions 113 of the drum cartridge 21 in a state where the process frame 52 to which the drum cartridge 21 is mounted is positioned at the inner position. doing.

  The belt frame main body 158 is provided between the belt left side wall 156 and the belt right side wall 157. The belt frame main body 158 has a substantially plate shape that is substantially rectangular in plan view. The belt frame main body 158 includes four transfer roller accommodating portions 161 and four pairs of bracket accommodating portions 162.

  The four transfer roller accommodating portions 161 are arranged in parallel at intervals in the front-rear direction. The transfer roller accommodating part 161 has a substantially semi-cylindrical shape with the lower part opened.

  The four pairs of bracket accommodating portions 162 are respectively disposed at both left and right ends of the corresponding transfer roller accommodating portion 161. The bracket accommodating portion 162 is recessed in a substantially rectangular shape in plan view from the lower surface of the belt frame main body 158 upward.

  The four pairs of brackets 166 are respectively disposed at the left and right ends of the corresponding primary transfer roller 42. The bracket 166 has a substantially plate shape that is substantially rectangular in a side view extending in the front-rear direction. The substantially center of the bracket 166 in side view is penetrated in a substantially circular shape in side view.

  Then, each of the four pairs of brackets 166 receives the both ends in the left-right direction of the corresponding primary transfer roller 42 and is accommodated in each of the four pairs of bracket accommodating portions 162, whereby each of the four primary transfer rollers 42 is Are accommodated in the corresponding transfer roller accommodating portions 161.

  As a result, the four primary transfer rollers 42 are arranged in parallel so as to be movable relative to the belt frame 155 with an interval in the front-rear direction.

Further, the driving roller 39 is rotatably supported at the rear end portion of the belt frame 155, the driven roller 40 is rotatably supported at the front end portion of the belt frame 155, and the intermediate transfer belt 41 is driven by the driving roller 39 and the driven roller. It is stretched around 40. That is, the belt frame 155 supports the intermediate transfer belt 41.
6). As shown in FIGS. 12 and 13, the four drum cartridges 21 are mounted on the belt frame 155 of the belt unit 37 in a state where the process frame 52 is located at the contact position in the inner position. Each drum frame 104 abuts from below.

  More specifically, the lower surface of the belt left side wall 156 of the belt frame 155, the lower surface of the belt right side wall 157, and the upper surfaces of the respective drum refracting portions 114 of the four drum frames 104 are in contact with each other. Each of the four pairs of positioning protrusions 160 is fitted in the positioning holes 121 of the four drum frames 104. That is, the positioning hole 121 is located outward in the left-right direction with respect to the intermediate transfer belt 41.

  Thus, each of the four drum cartridges 21 is positioned with respect to the belt frame 155, and each photosensitive drum 26 of the four drum cartridges 21 sandwiches the intermediate transfer belt 41 with respect to the corresponding primary transfer roller 42. Facing each other and in contact with the intermediate transfer belt 41.

When the process frame 52 is located at the contact position on the inner side position, the drum gripping portions 113 of the yellow drum cartridge 21Y, the magenta drum cartridge 21M, and the cyan drum cartridge 21C are intermediate transfer as viewed from the left-right direction. It overlaps with the belt 41. Further, in the black drum cartridge 21K, the left black drum gripping portion 134 and the right black drum gripping portion 135 overlap with the belt unit 37 when viewed from the left-right direction.
7). Detaching operation of the drum cartridge and developing cartridge (1) Detaching operation of the drum cartridge and developing cartridge In order to detach the drum cartridge 21 and the developing cartridge 22 from the main body casing 2, first, a process is performed from the main body casing 2. The frame 52 is pulled out and moved from the inner position to the outer position.

  In order to move the process frame 52 from the inner position to the outer position, first, as shown in FIG. 14, the front cover 7 is swung and moved from the closed position to the open position.

  Then, in conjunction with the swing of the front cover 7, the process frame 52 moves downward from the contact position at the inner position by an interlock mechanism (not shown), and the photosensitive drum 26 of each of the four drum cartridges 21 from the intermediate transfer belt 41. Moves to a separated position where the At this time, the engagement between the four pairs of positioning protrusions 160 of the belt unit 37 and the positioning holes 121 of the four drum cartridges 21 is released.

  Next, as shown in FIG. 15, the user grips the process gripping portion 75 and slides the process frame 52 so as to pull it out forward.

  Thereby, the process frame 52 is pulled out to the outside of the main body casing 2 through the main body opening 6, and is positioned at the outer position.

  Next, the drum cartridge 21 is detached from the process frame 52. In order to detach the drum cartridge 21 from the process frame 52, as shown in FIG. 19, the user holds the drum holding portion 113 and pulls the drum cartridge 21 upward. In FIG. 19, of the four drum cartridges 21, the yellow drum cartridge 21Y is detached.

  16A and 16B, the contact between the extending portion 132 of the drum frame 104 and the roller 93 of the urging portion 87 is released, and the roller 93 is moved upward by the urging force of the compression spring 92. Is urged to.

  As a result, the second guide shaft 97 is moved from the lower end portion to the upper end portion of the first guide groove 90, the first guide shaft 96 is moved from approximately the center in the front-rear direction of the second guide groove 91 to the front upper end portion, and the cover portion. 88 moves from the exposed position where the LED array 82 is exposed to a covering position where the LED array 82 is covered.

  Further, as shown in FIGS. 17A and 17B, the drum cartridge 21 moves upward with respect to the corresponding developing cartridge 22, so that the contact portion 117 of the drum frame 104 and the developing grip portion 143 of the developing frame 140 The contact with the swinging part 145 is released, and the swinging part 145 moves from the housed position to the protruding position by the urging force of the torsion spring 146.

  Then, the yellow drum cartridge 21Y detached from the process frame 52 is placed so as to be superimposed on the magenta drum cartridge 21M, as shown in FIGS. Specifically, the receiving groove 122 of the mounting portion 115 of the drum frame 104 of the yellow drum cartridge 21Y engages with the upper end portion of the drum gripping portion 113 of the magenta drum cartridge 21M, so that the magenta drum cartridge 21M The yellow drum cartridges 21Y are stacked.

  As shown in FIG. 19, in the black drum cartridge 21 </ b> K, the left black drum gripping portion 134 includes the flat plate portion 136, so that it cannot be engaged with the receiving groove 122. Further, the right black drum gripping part 135 can be engaged with the receiving groove 122, but the upper end part of the left black drum gripping part 134 and the upper end part of the right black drum gripping part 135 have different vertical dimensions. Therefore, when the yellow drum cartridge 21Y, the magenta drum cartridge 21M, and the cyan drum cartridge 21C are stacked with respect to the black drum cartridge 21K, they are inclined and the balance is deteriorated so that they cannot be stacked substantially. It is configured.

  Then, as shown in FIG. 18, the yellow developing cartridge 22Y from which the corresponding yellow drum cartridge 21Y has been detached is pulled upward by the user holding the left and right swinging portions 145.

Thus, the detaching operation of the drum cartridge 21 and the developing cartridge 22 from the main body casing 2 is completed.
(2) Mounting operation of drum cartridge and developing cartridge To mount the drum cartridge 21 and the developing cartridge 22 on the main body casing 2, first, the developing cartridge 22 is mounted on the process frame 52.

  To attach the developing cartridge 22 to the process frame 52, as shown in FIG. 2, the developing cartridge 22 is moved from the process frame 52 with respect to the corresponding developing cartridge accommodating portion 101 in a state where the corresponding drum cartridge 21 is detached. And attach from above. Specifically, in the developing cartridge 22, a pair of first developing engagement portions 151 are guided from above to below by a pair of first developing engagement grooves 68, and a pair of second developing engagement portions 152 are formed. A pair of second developing engagement grooves 69 are mounted in the corresponding developing cartridge accommodating portions 101 so as to be guided downward from above.

  Next, the drum cartridge 21 is mounted on the corresponding drum cartridge housing portion 100 from above in a state where the corresponding developing cartridge 22 is mounted on the process frame 52. Specifically, on the left side of the drum cartridge 21, the first drum engaging portion 116 is guided from above to below by the first drum engaging groove 70, and the second drum engaging portion 118 is engaged with the second drum engaging portion. The groove 71 guides from above to below. On the right side, the drum cartridge 21 is mounted in the corresponding drum cartridge accommodating portion 100 such that the first drum engaging portion 116 is guided from above to below with respect to the first drum engaging groove 70. Is done.

  As a result, as shown in FIG. 17B, the abutting portion 117 of the drum cartridge 21 is brought into contact with the swinging portion 145 of the developing cartridge 22 from above, and the swinging portion 145 of the developing cartridge 22 is As shown, the torsion spring 146 moves from the protruding position to the receiving position against the urging force.

  Then, as shown in FIGS. 12 and 15, the process frame 52 is moved from the outer position to the contact position at the inner position by the reverse procedure described above.

Thus, the mounting operation of the drum cartridge 21 and the developing cartridge 22 to the main casing 2 is completed.
8). Operation and Effect (1) According to this printer 1, as shown in FIG. 1 and FIG. So that the printer 1 can form an image.

  Also, as shown in FIGS. 15 and 19, the photosensitive drum 26 is moved from below the intermediate transfer belt 41 by placing the process frame 52 at the outer position so that the drum cartridge 21 can be detached. Can do.

  In the state in which the drum cartridge 21 can be detached, the intermediate transfer belt 41 facing the upper side of the photosensitive drum 26 disappears, so that the upper part of the photosensitive drum 26 is exposed, but the drum frame 104 includes the drum gripping portion 113. Therefore, the user can easily access the drum cartridge 21 without touching the photosensitive drum 26 and can exchange the drum cartridge 21.

  Furthermore, since only the drum cartridge 21 can be detached while the developing cartridge 22 is mounted on the process frame 52, the photosensitive drum 26 can be replaced or maintained.

As a result, only the drum cartridge 21 can be easily detached from the process frame 52 while suppressing the user from touching the photosensitive drum 26.
(2) Further, according to the printer 1, as shown in FIGS. 2 and 7A, the drum gripping portions 113 are disposed at the left and right ends of the drum frame 104, so that the user can reliably make the drum gripping portion 113. Can be recognized.

  Therefore, it is possible to further suppress the user from touching the photosensitive drum 26.

Further, compared to the case where the drum gripping portion 113 is provided only at one end portion of the drum frame 104 in the left-right direction, the user can grip both the left and right end portions of the drum frame 104, so that the drum frame 104 can be stabilized. And can be removed.
(3) Also, according to this printer 1, as shown in FIGS. 12 and 14, the drum gripping portion 113 overlaps the intermediate transfer belt 41 in a side view with the process frame 52 positioned at the inner position. As a result, it is arranged to be above the photosensitive drum 26.

  Therefore, as shown in FIGS. 15 and 19, the user can easily recognize the drum grip 113 when accessing the drum cartridge 21, so that it is not the photosensitive drum 26 exposed upward. The drum gripping portion 113 can be securely gripped.

As a result, the user can reliably hold the drum holding portion 113 without touching the photosensitive drum 26 and can remove the drum cartridge 21 from the process frame 52.
(4) According to the printer 1, as shown in FIGS. 2 and 7A, the drum gripping portion 113 includes a pair of gripping protrusions 125 and a gripping connection portion 126. By gripping the grip connecting portion 126 of the drum gripping portion 113, the drum cartridge 21 can be stably attached to and detached from the process frame 52.
(5) Further, according to the printer 1, as shown in FIGS. 1 and 6B, when the drum cartridge 21 is mounted on the process frame 52, the photosensitive drum is viewed from above with respect to the LED array 82 of the LED unit 23. 26 face each other, the LED array 82 of the LED unit 23 can be protected by the photosensitive drum 26.

  As shown in FIGS. 4A and 4B, when the drum cartridge 21 is detached from the process frame 52, the LED array 82 of the LED unit 23 is protected by the cover 88 instead of the protection by the photosensitive drum 26. be able to.

As a result, the life of the LED unit 23 can be extended.
(6) Also, according to the printer 1, as shown in FIGS. 2 and 19, even if the usage frequencies of the four photosensitive drums 26 and the four developing cartridges 22 are different, It can be replaced individually or maintenance can be performed.
(7) According to the printer 1, as shown in FIGS. 1 and 8, the dimension between the adjacent drum frames 104 is set to 0.5 mm or more and 8 mm or less. Therefore, when an arbitrary drum cartridge 21 is detached, a user puts a hand between the drum frame 104 of the drum cartridge 21 and the drum frame 104 of the drum cartridge 21 adjacent to the drum cartridge 21 to remove the drum cartridge 21. It can suppress trying.

Therefore, when the drum cartridge 21 is detached, the user can recognize the drum grip 113 more reliably.
(8) Also, according to the printer 1, as shown in FIGS. 1 and 8, no step is formed on the upper surface of the adjacent drum frames 104, so that the user has no gap between the adjacent drum frames 104. This can be easily recognized.

Therefore, it is possible to further suppress the user from putting his hand between the adjacent drum frames 104 to remove the drum cartridge 21.
(9) Further, according to the printer 1, as shown in FIG. 8, the arrangement order of the four drum cartridges 21 in the front-rear direction cannot be changed. In the case of being detached from the above and reattached, it can be reliably attached above the corresponding developing cartridge 22.
(10) Further, according to the printer 1, as shown in FIGS. 8 and 19, the cyan drum cartridge 21C is configured by a simple configuration in which the cyan drum convex portion 128C and the magenta drum concave portion 130M are engaged. The magenta drum cartridge 21M can be engaged.

Therefore, since the pitch between the cyan drum cartridge 21C and the magenta drum cartridge 21M can be fixed, the accuracy of the image forming operation can be improved.
(11) Further, according to the printer 1, as shown in FIGS. 8 and 19, the cyan drum convex portion 128C has a convex shape, and the magenta drum concave portion 130M has a concave shape. The drum convex portion 128C and the magenta drum concave portion 130M can be easily engaged.
(12) According to the printer 1, as shown in FIG. 8, the positions of the magenta drum convex portion 128M and the yellow drum concave portion 130Y in the left-right direction are the cyan drum convex portion 128C and the magenta drum concave portion 130M. The arrangement order of the yellow drum cartridge 21Y, the magenta drum cartridge 21M, and the cyan drum cartridge 21C cannot be changed.

Therefore, each of the yellow drum cartridge 21Y, the magenta drum cartridge 21M, and the cyan drum cartridge 21C can be securely mounted above the corresponding developing cartridge 22.
(13) Also, according to the printer 1, as shown in FIG. 8, the magenta drum convex portion 128M has a convex shape, and the yellow drum concave portion 130Y has a concave shape. 128M and the yellow drum recess 130Y can be easily engaged with each other.
(14) According to the printer 1, as shown in FIGS. 8 and 19, the black drum convex portion 128K and the process concave portion 76 are engaged with each other from the position inside the process frame 52 as shown in FIGS. The black drum cartridge 21 </ b> K located on the most downstream side in the direction toward the outer position can be mounted on the process frame 52.

Further, the black drum cartridge 21K can be mounted on the process frame 52 with a simple configuration in which the positions of the black drum convex portion 128K and the process concave portion 76 in the left-right direction are different from the cyan drum convex portion 128C and the magenta drum concave portion 130M. It can be attached to the drum cartridge housing part 100 at the foremost end.
(15) Further, according to this printer 1, as shown in FIGS. 8 and 19, the black drum convex portion 128K has a convex shape, and the process concave portion 76 has a concave shape. The protrusion 128K and the process recess 76 can be easily engaged.
(16) Further, according to the printer 1, as shown in FIGS. 2 and 19, the four drum cartridges 21 and the four developing cartridges 22 are individually connected to the process frame 52 located at the outer position. Can be separated upward.

  At this time, since the developing cartridge 22 is disposed below the drum cartridge 21, only the drum cartridge 21 can be detached while the developing cartridge 22 is attached to the process frame 52.

In addition, the user can detach the drum cartridge 21 from the process frame 52 with a simple configuration of gripping the drum gripping portion 113 and extracting the drum cartridge 21 upward.
(17) According to the printer 1, as shown in FIGS. 19 and 20, when one of the four drum cartridges 21 is detached from the process frame 52, the other drum cartridges 21 are removed. The detached drum cartridge 21 can be stacked.

For this reason, a space for placing the detached drum cartridge 21 is not required, and space can be saved when the photosensitive drum 26 is replaced or maintained.
(18) Further, according to the printer 1, when one drum frame 104 of the four drum frames 104 is stacked on the other drum frame 104 as shown in FIGS. Stacking can be achieved by simply placing the placement portion 115 of one drum frame 104 on the drum gripping portion 113 of the drum frame 104.

Therefore, the four drum cartridges 21 can be easily and reliably stacked.
(19) Also, according to the printer 1, as shown in FIG. 19, the black drum cartridge 21K is different from the other drum cartridges 21 in that the black drum cartridge 21K has a left black drum gripping portion 134, By including the right black drum grip portion 135, the other drum cartridges 21 are configured so as not to be stacked.

  For this reason, when the process frame 52 is positioned at the outer position, it is possible to suppress the load from being applied to the position farthest from the main casing 2 by stacking the other drum cartridge 21 on the black drum cartridge 21K. Therefore, it can suppress that the main body casing 2 inclines.

As a result, the main casing 2 can be stabilized even when the process frame 52 is positioned at the outer position and the drum cartridge 21 is replaced or maintained.
(20) Also, according to the printer 1, as shown in FIGS. 11 and 12, the belt unit 37 and the four drum frames 104 can be positioned more inwardly in the left-right direction than the drum gripping portion 113. it can.

  Therefore, the positioning protrusion 160 can be prevented from being damaged by the drum gripping portion 113.

As a result, the four drum frames 104 can be reliably positioned with respect to the belt unit 37, and the four photosensitive drums 26 can be brought into contact with the intermediate transfer belt 41 at a constant pitch.
9. Second Embodiment A second embodiment of the printer 1 will be described with reference to FIGS. 21A and 21B. In the second embodiment, members similar to those in the first embodiment described above are denoted by the same reference numerals, and description thereof is omitted.
(1) Configuration of Drum Cartridge of Second Embodiment In the second embodiment, the drum cartridge 21 does not include a pair of drum gripping portions 113 and a pair of contact portions 117. One drum piece gripping part 170 as an example and a pair of pressing parts 171 are provided.

  The drum piece gripping portion 170 is disposed at the left end portion of the drum cartridge 21. The drum piece gripping portion 170 includes a base portion 174, a first portion 175, and a second portion 176.

  The base 174 protrudes leftward from the left surface at the rear upper end of the drum side wall body 112 of the drum left side wall 105.

  The first portion 175 has a substantially prismatic shape extending upward from the upper surface of the base portion 174.

  The second portion 176 has a substantially prismatic shape extending forward from the upper end of the first portion 175. The second portion 176 includes a plurality of irregularities arranged in parallel along the front-rear direction so that the user can easily grip the second portion 176. Note that the second portion 176 is disposed on the left side of the positioning hole 121.

The pressing portion 171 has a substantially plate shape that is continuous from the front end portion of the drum refracting portion 114 and has a substantially rectangular shape in plan view and extends forward.
(2) Configuration of Development Cartridge of Second Embodiment In the second embodiment, the development cartridge 22 does not include the development gripping part 143 but includes a pair of development slide gripping parts 179 as an example of the development gripping part. ing.

  The pair of developing slide grips 179 are disposed at both left and right ends of the developing frame 140. The development slide gripping part 179 includes a base part 180 and a slide part 181 as an example of a moving part.

The base portion 180 has a substantially prismatic shape extending upward from both left and right end portions on the upper surface of the developing frame 140.
The dimension between the right end portion of the left base portion 180 and the left end portion of the right base portion 180 is slightly larger than the horizontal dimension of the protrusion 127 of the drum cartridge 21. The base portion 180 includes a slide guide 183.

  The slide guide 183 protrudes rearward from approximately the center in the left-right direction on the rear surface of the base portion 180. The slide guide 183 has a substantially prismatic shape extending across the entire vertical direction of the base portion 180.

  The slide part 181 includes a standing part 185, a developing part 186, and a reinforcing part 187.

  The standing portion 185 has a substantially prismatic shape extending along the vertical direction. The standing portion 185 includes a guide groove 188.

  The guide groove 188 is recessed rearward from a substantially central portion in the left-right direction on the front surface of the standing portion 185. The guide groove 188 extends over the entire vertical direction of the standing portion 185.

  The development part 186 has a substantially prismatic shape extending from the upper end part of the standing part 185 outward in the left-right direction.

  The reinforcing part 187 connects the outer surface of the standing part 185 in the left-right direction and the lower surface of the development part 186. The reinforcing portion 187 has a substantially plate shape having a substantially triangular shape in front view that is inclined upward as the lower surface of the reinforcing portion 187 goes outward in the left-right direction.

  Then, the slide portion 181 has its tip relatively separated from the developing frame 140 as shown in FIG. 21B by fitting the slide guide 183 of the base portion 180 into the guide groove 188 of the standing portion 185. As shown in FIG. 21A, the distance between the tip and the developing frame 140 is smaller than the protruding position, and the sliding position can be moved between the housing position relatively close to the developing frame 140. It is assembled.

In addition, as shown to FIG. 21B, the slide part 181 is urged | biased from the accommodation position toward the protrusion position by the urging | biasing force of the urging member which is not shown in figure.
(3) Mounting and Demounting of Drum Cartridge and Developer Cartridge to Process Frame In the second embodiment, each of the four drum cartridges 21 and the four developer cartridges 22 is not shown, but, as in the first embodiment, The drum cartridge accommodating portion 100 and the four developing cartridge accommodating portions 101 are accommodated.

  When both the drum cartridge 21 and the developing cartridge 22 are attached to the process frame 52, as shown in FIG. 21A, the upper surface of the developing portion 186 of the developing slide holding portion 179 of the developing cartridge 22 is shown. The pressing portion 171 of the drum cartridge 21 is in contact.

  Thereby, in the pair of developing slide gripping portions 179, the slide portion 181 is positioned at the accommodation position against the biasing force of the biasing member (not shown).

  Further, by moving the drum cartridge 21 upward with respect to the corresponding developing cartridge 22, the contact of the pressing portion 171 of the drum frame 104 with the developing portion 186 of the developing slide gripping portion 179 of the developing frame 140 is released. The developing slide grip 179 is moved from the storage position to the protruding position by a biasing force of a biasing member (not shown).

  Then, the developing cartridge 22 from which the corresponding drum cartridge 21 is detached is pulled upward by the user holding the developing portion 186 of the left and right slide portions 181.

  Further, when the drum cartridge 21 is mounted on the process frame 52 to which the corresponding developing cartridge 22 is mounted from above, the drum cartridge 21 is pressed against the developing portion 186 of the slide portion 181 of the developing cartridge 22. The part 171 is abutted from above.

  As a result, as shown in FIG. 21A, the slide portion 181 of the developing cartridge 22 moves from the protruding position to the accommodation position against the biasing force of a spring member (not shown).

In this way, the drum cartridge 21 and the developing cartridge 22 are attached to and detached from the process frame 52.
(4) Effects of Second Embodiment According to the printer 1 of the second embodiment, as shown in FIGS. 21A and 21B, the drum cartridge 21 includes the drum piece gripping portion 170, and the drum piece gripping portion 170 is A first portion 175 extending upward and a second portion 176 extending forward from the upper end of the first portion 175 are provided.

  In the drum piece gripping portion 170, since the front end of the second portion 176 is open, the user can easily access the second portion 176 and grip the drum piece gripping portion 170.

Also in the second embodiment, the same effects as those in the first embodiment described above can be obtained.
10. Third Embodiment A third embodiment of the printer 1 will be described with reference to FIG. Note that in the third embodiment, members similar to those in the first embodiment described above are denoted by the same reference numerals, and descriptions thereof are omitted.
(1) Configuration of Drum Cartridge of Third Embodiment In the first embodiment described above, the second drum engaging portion 118 is arranged at the same position in each of the four drum cartridges 21. On the other hand, in the third embodiment, the arrangement of the four drum cartridges 21 in the front-rear direction is different from each other. Specifically, the second drum engaging portion 118 of the black drum cartridge 21K is the black second drum engaging portion 118K, the second drum engaging portion 118 of the yellow drum cartridge 21Y is the yellow second drum engaging portion 118Y, and magenta. The second drum engaging portion 118 of the drum cartridge 21M will be referred to as a magenta second drum engaging portion 118M, and the second drum engaging portion 118 of the cyan drum cartridge 21C will be referred to as a cyan second drum engaging portion 118C.

  The black second drum engaging portion 118 </ b> K is disposed slightly rearward of the substantially central portion in the front-rear direction of the mounting portion 115 of the drum left side wall 105.

  The yellow second drum engagement portion 118Y is a rear portion of the placement portion 115 of the drum left side wall 105 and is disposed behind the black second drum engagement portion 118K.

  The magenta second drum engagement portion 118M is disposed slightly forward of the rear end portion of the placement portion 115 of the drum left side wall 105 and rearward of the yellow second drum engagement portion 118Y.

  The cyan second drum engaging portion 118C is a rear end portion of the mounting portion 115 of the drum left side wall 105 and is disposed rearward of the magenta second drum engaging portion 118M.

  Although not shown, in the drum cartridge housing portions 100 corresponding to the four drum cartridges 21, the second drum engagement grooves 71 correspond to the second drum engagement portions 118 of the four drum cartridges 21. The arrangement in the front-rear direction is different.

  Therefore, when the four drum cartridges 21 are accommodated in the drum cartridge accommodating portion 100, the arrangement order in the front-rear direction cannot be changed by being accommodated only in the corresponding drum cartridge accommodating portion 100. Yes.

Further, the black drum cartridge 21K includes the left black drum gripping portion 134 and the right black drum gripping portion 135 in the first embodiment described above, whereas in the third embodiment, other than the black drum cartridge 21K. Like the three drum cartridges 21, a drum grip 113 is provided.
(2) Configuration of Developer Cartridge of Third Embodiment In the first embodiment described above, the second developer engaging portion 152 is disposed at the same position in each of the four developer cartridges 22. On the other hand, in the third embodiment, the arrangement in the front-rear direction differs depending on each of the four developing cartridges 22. Specifically, the second development engagement portion 152 of the black development cartridge 22K is the black second development engagement portion 152K, the second development engagement portion 152 of the yellow development cartridge 22Y is the yellow second development engagement portion 152Y, and magenta. The second developing engagement portion 152 of the developing cartridge 22M is referred to as a magenta second developing engaging portion 152M, and the second developing engaging portion 152 of the cyan developing cartridge 22C is referred to as a cyan second developing engaging portion 152C.

  The black second developing engagement portion 152K is disposed at a substantially central portion in the front-rear direction of the developing frame 140 and the bearing member 141.

  The yellow second developing engagement portion 152Y is disposed slightly rearward of the developing frame 140 and the substantially central portion in the front-rear direction of the bearing member 141 and rearward of the black second developing engagement portion 152K.

  The magenta second developing engagement portion 152M is disposed slightly in front of the rear end portions of the developing frame 140 and the bearing member 141 and behind the yellow second developing engagement portion 152Y.

  The cyan second developing engagement portion 152C is a rear end portion of the developing frame 140 and the bearing member 141, and is arranged behind the magenta second developing engagement portion 152M.

  Although not shown, in the developing cartridge storage portions 101 corresponding to the four developing cartridges 22, the second developing engaging grooves 69 corresponding to the second developing engaging portions 152 of the four developing cartridges 22, respectively. The arrangement in the front-rear direction is different.

Therefore, when the four developing cartridges 22 are housed in the developing cartridge housing portion 101, they can be housed only in the corresponding developing cartridge housing portion 101, so that the arrangement order in the front-rear direction cannot be changed. Yes.
(3) Effects of the Third Embodiment According to the printer 1 of the third embodiment, as shown in FIG. 22, the arrangement of the second drum engaging portions 118 of the four drum cartridges 21 is different. According to the configuration, the arrangement order of the four drum cartridges 21 cannot be changed.

Also in the third embodiment, the same operational effects as those of the first embodiment described above can be obtained.
11. Fourth Embodiment A fourth embodiment of the printer 1 will be described with reference to FIGS. 23A and 23B. Note that in the fourth embodiment, members similar to those described in the first embodiment are denoted by the same reference numerals, and descriptions thereof are omitted.

  In the fourth embodiment, the image forming unit 4 does not include the four drum cartridges 21 and the four developing cartridges 22 but includes a plurality, that is, four process cartridges 200. The front cover 7 includes a process cartridge housing portion 214, and the belt unit 37 includes four pairs of positioning holes 218.

In the following description, when referring to the direction with respect to the process cartridge 200, the orientation when the process cartridge 200 is attached to and detached from the front cover 7 located at the closed position is used as a reference. Specifically, the direction arrow shown in the figure is used as a reference.
(1) Process Cartridge The process cartridge 200 includes a drum unit 201 as an example of a drum cartridge and a developer unit 202 as an example of a developing cartridge.

  The drum unit 201 includes the photosensitive drum 26 described above and the scorotron charger 27 described above, and constitutes an upper portion of the process cartridge 200. The drum unit 201 includes a drum frame 204.

  The drum frame 204 has a substantially rectangular tube shape that extends in the left-right direction and whose left end and right end are closed. Note that the upper wall of the drum frame 204 is communicated in the left and right directions, and the upper end portion of the photosensitive drum 26 is exposed. The upper end portion of the photosensitive drum 26 protrudes above the upper surface of the drum frame 204. Although not shown, the lower wall of the drum frame 204 communicates with the inside and outside in the left-right direction, and the lower end of the photosensitive drum 26 is exposed. The drum frame 204 includes a pair of drum gripping portions 205 and a pair of positioning protrusions 206 as an example of an engaging portion.

  The pair of drum gripping portions 205 are disposed at both end portions of the drum frame 204 in the left-right direction. The drum gripping portion 205 has a substantially plate shape that is substantially L-shaped when viewed from the front, extending upward from both ends in the left-right direction on the upper surface of the drum frame 204 and extending outward in the left-right direction.

  The pair of positioning protrusions 206 are disposed adjacent to each other inward in the left-right direction of the pair of drum grips 205. The positioning protrusion 206 has a convex shape with a substantially rectangular cross section that protrudes upward from the upper surface of the drum frame 204. The left and right outer end portions of the positioning protrusion 206 are continuous with the inner surface of the drum gripping portion 205 in the left and right direction.

  The developer unit 202 includes the above-described developing roller 30, the above-described supply roller 31, the above-described layer thickness regulating blade 32, and the above-described toner container 33, and constitutes a lower portion of the process cartridge 200. . The developer unit 202 includes a development frame 209.

  The developing frame 209 has a substantially rectangular tube shape that extends in the left-right direction and has a left end portion and a right end portion closed. Although not shown, the upper wall of the developing frame 209 communicates with the inside and outside in the left-right direction, and the upper end of the developing roller 30 is exposed. The developing roller 30 is in contact with the lower end portion of the photosensitive drum 26.

  The developing frame 209 includes a pair of first engaging portions 210 and a pair of second engaging portions 211.

  The pair of first engaging portions 210 has a substantially cylindrical shape that protrudes outward in the left-right direction from the outer surface in the left-right direction at the front lower ends of the left and right side walls of the developing frame 209.

The pair of second engaging portions 211 has a substantially cylindrical shape that protrudes outward in the left-right direction from the outer surface in the left-right direction at the rear lower ends of the left and right side walls of the developing frame 209.
(2) Front cover As described above, the front cover 7 has its lower end portion as a fulcrum, a closed position along the vertical direction so as to close the main body opening 6, and a front-back direction so as to open the main body opening 6. Can be swung between the open position and the open position. The front cover 7 has a bottomed frame plate shape that is substantially rectangular in a plan view in a state where the front cover 7 is located at the closed position.

The process cartridge housing portion 214 is recessed in a substantially rectangular shape in plan view from the upper surface of the front cover 7 located at the open position downward. The process cartridge accommodating portion 214 is configured to accommodate the four process cartridges 200 in parallel in the front-rear direction. Although not shown, the process cartridge accommodating portion 214 is an engagement that can be engaged with the pair of first engaging portions 210 and the pair of second engaging portions 211 of each of the four process cartridges 200. An engagement hole is provided.
(3) Belt unit The belt unit 37 is different in position and orientation from the first embodiment, and is arranged along the vertical direction in the rear portion of the main casing 2. Although not shown, the belt unit 37 includes a driving roller 39 disposed below and a driven roller 40 disposed above. An intermediate transfer belt 41 is stretched around the driving roller 39 and the driven roller 40. Although not shown, the four primary transfer rollers 42 are arranged in parallel in the vertical direction between the driving roller 39 and the driven roller 40 with a space therebetween.

  The belt frame 155 of the belt unit 37 does not include the four pairs of positioning protrusions 160 but includes four pairs of positioning holes 218 as an example of a positioning portion.

The four pairs of positioning holes 218 are arranged at intervals in the vertical direction at both ends in the left-right direction of the belt frame 155. The positioning hole 218 has a concave shape that is recessed in a substantially rectangular shape in front view from the front surface of the belt frame 155 toward the rear.
(4) Attaching / detaching the process cartridge to / from the main body casing The process cartridge 200 is inserted into the process cartridge housing portion 214 from above by the user holding the pair of drum grip portions 205 on the front cover 7 located at the open position. By doing so, it is attached to the process cartridge housing portion 214.

  Then, by moving the front cover 7 on which the four process cartridges 200 are mounted from the open position to the closed position, the pair of positioning protrusions 206 of each of the four process cartridges 200 becomes four pairs of belt frames 155. Inserted into each of the positioning holes 218.

  Thus, the four process cartridges 200 are arranged in parallel in the vertical direction in the main body casing 2 so that the respective photosensitive drums 26 face the corresponding primary transfer rollers 42 (not shown) with the intermediate transfer belt 41 interposed therebetween. Be placed.

  Thus, the mounting operation of the process cartridge 200 with respect to the main casing 2 is completed.

  In order to remove the process cartridge 200 from the main casing 2, the front cover 7 is moved from the closed position to the open position by the reverse procedure described above.

  Then, the pair of drum gripping portions 205 are gripped, and the process cartridge 200 is detached from the process cartridge housing portion 214.

As described above, the separation operation of the process cartridge 200 from the main casing 2 is completed.
(5) Effects of the Fourth Embodiment According to the printer 1 of the fourth embodiment, as shown in FIGS. 23A and 23B, the intermediate transfer belt 41 that faces the photosensitive drum 26 in a state where the process cartridge 200 can be detached. As a result, the upper part of the photosensitive drum 26 is exposed. However, since the drum unit 201 includes the pair of drum grips 205, the user can easily attach the process cartridge 200 to the process cartridge 200 without touching the photosensitive drum 26. The process cartridge 200 can be replaced.
12 Modification The printer 1 described above is an embodiment of the image forming apparatus of the present invention, and the present invention is not limited to the above-described embodiment.

  In the embodiment described above, the cyan drum cartridge 21C is an example of the first drum cartridge, the magenta drum cartridge 21M is an example of the second drum cartridge, and the yellow drum cartridge 21Y is an example of the third drum cartridge.

  On the other hand, of the four drum cartridges 21, the magenta drum cartridge 21M is an example of the first drum cartridge, the yellow drum cartridge 21Y is an example of the second drum cartridge, and the black drum cartridge 21K is an example of the third drum cartridge. You can also

  In such a case, the magenta drum convex portion 128M of the magenta drum cartridge 21M is an example of the first engaging portion, and the yellow drum concave portion 130Y that engages with the magenta drum convex portion 128M is an example of the first engaged portion. It is. The yellow drum convex portion 128Y is an example of the second engaging portion, and the black drum concave portion 130K that engages with the yellow drum convex portion 128Y is an example of the second engaging portion.

  Further, in the first embodiment described above, the arrangement of the drum convex portions 128 of the four drum cartridges 21 in the left-right direction is different, and correspondingly, other than the process concave portions 76 of the process frame 52 and the black drum cartridge 21K. By arranging the respective drum recesses 130 of the three drum cartridges 21, the arrangement order of the four drum cartridges 21 cannot be changed.

  In contrast, at least one of the number, shape, and size of the drum protrusions 128 of each of the four drum cartridges 21 is different, and the process recesses 76 of the process frame 52 and the black drum are corresponding thereto. By configuring the drum recesses 130 of the three drum cartridges 21 other than the cartridge 21K, the arrangement order of the four drum cartridges 21 can be configured to be unchangeable.

  Further, in the third embodiment described above, the second drum engaging portions 118 of the four drum cartridges 21 have different arrangements in the front-rear direction, and correspondingly, the second drum engaging portions 118 of the four drum cartridge accommodating portions 100 respectively. By arranging the two drum engagement grooves 71, the arrangement order of the four drum cartridges 21 cannot be changed.

  In contrast, at least one of the number, shape, and size of the second drum engaging portions 118 of each of the four drum cartridges 21 is different, and each of the four drum cartridge accommodating portions 100 is corresponding to it. By configuring the second drum engagement groove 71, the arrangement order of the four drum cartridges 21 can be configured to be unchangeable.

  In the third embodiment described above, the second developing engagement portions 152 of the four developing cartridges 22 have different arrangements in the front-rear direction. Since the two developing engagement grooves 69 are arranged, the arrangement order of the four developing cartridges 22 cannot be changed.

  On the other hand, at least one of the number, shape, and size of the second developing engagement portions 152 of each of the four developing cartridges 22 is different, and each of the four developing cartridge housing portions 101 is corresponding to it. By configuring the second developing engagement groove 69, the arrangement order of the four developing cartridges 22 can be configured to be unchangeable.

DESCRIPTION OF SYMBOLS 1 Printer 2 Main body casing 21 Drum cartridge 21K Black drum cartridge 21Y Yellow drum cartridge 21M Magenta drum cartridge 21C Cyan drum cartridge 22 Developing cartridge 23 LED unit 26 Photosensitive drum 37 Belt unit 41 Intermediate transfer belt 42 Primary transfer roller 52 Process frame 53 Process left side Wall 54 Right side wall of process 68 First development engagement groove 69 Second development engagement groove 70 First drum engagement groove 71 Second drum engagement groove 76 Process recessed portion 88 Cover portion 100 Drum cartridge housing portion 104 Drum frame 113 Drum gripping Part 115 Placement part 117 Contact part 121 Positioning hole 125 Grasping protrusion part 126 Grasping connection part 128 Drum convex part 128K Black drum convex part 1 28Y Yellow drum convex portion 128M Magenta drum convex portion 128C Cyan drum convex portion 130 Drum concave portion 130K Black drum concave portion 130Y Yellow drum concave portion 130M Magenta drum concave portion 140 Developing frame 143 Developing gripping portion 145 Swing portion 146 Torsion spring 155 Belt frame 160 Positioning protrusion Part 170 Drum piece gripping part 175 First part 176 Second part 179 Development slide gripping part 181 Slide part 201 Drum unit 202 Developer unit 204 Drum frame 205 Drum gripping part 206 Positioning projection part 218 Positioning hole A Axis

Claims (22)

The device body;
A belt unit having a belt;
A plurality of drum cartridges having a photosensitive drum having an axis extending in the first direction; and a drum frame supporting the photosensitive drum, the drum frame having a drum gripping portion disposed at one end in the first direction ; ,
A plurality of developing cartridges containing developer;
The plurality of drum cartridges and the plurality of developing cartridges are movable in a second direction orthogonal to the first direction between an inner position in the apparatus main body and an outer position outside the apparatus main body. And a support configured to removably support,
The plurality of drum cartridges and the plurality of developing cartridges are arranged in parallel in the second direction while being supported by the support.
When located at the inner position with said support supporting the previous SL plurality of drum cartridges Contact good beauty before Kifuku number of the developing cartridge, the plurality of drum cartridges are disposed below the belt unit The plurality of developing cartridges are disposed below the plurality of drum cartridges,
Each of the plurality of drum cartridges includes a mounting portion for stacking from above the drum cartridges other than the drum cartridge.
Of the plurality of drum cartridges, the drum gripping portion of the drum cartridge other than the drum cartridge located at the most downstream in the direction from the inner position to the outer position is the front of the drum cartridge other than the drum cartridge. Can be engaged with the mounting portion,
Among the plurality of drum cartridges, the drum gripping portion of the drum cartridge that is located on the most downstream side in the direction from the inner position toward the outer position engages with the placement portion of the drum cartridge other than the drum cartridge. An image forming apparatus, which is impossible .   The image forming apparatus according to claim 1, wherein the drum frame includes a pair of drum gripping portions at both ends in the first direction. 3. The image according to claim 1, wherein the drum gripping portion overlaps the belt when viewed from the first direction in a state where the support body is located at the inner position. 4. Forming equipment. The drum gripping part is
A pair of protrusions spaced from each other in the second direction;
The image forming apparatus according to claim 1, further comprising a connecting portion that connects the pair of protruding portions. The drum gripping part is
A first portion extending upward;
The image forming apparatus according to claim 1, further comprising a second portion extending along the second direction from the first portion. The support is
An exposure member configured to expose the photosensitive drum, wherein the exposure member is disposed below the photosensitive drum in a state where the support member supports the drum cartridge;
A covering member configured to move between an exposure position that exposes the exposure member when the drum cartridge is mounted and a coating position that covers the exposure member when the drum cartridge is detached; The image forming apparatus according to claim 1, wherein the image forming apparatus is provided. In the second direction, the dimension between said drum frame adjacent to each other, 0.5 mm or more and that this is 8mm or less, an image forming apparatus according to any one of claims 1-6. In the second direction, the said drum frame adjacent to each other, characterized in that their upper surface is arranged to be flush, the image forming apparatus according to any one of claims 1 to 7 . Wherein the plurality of drum cartridges are characterized in that sorted in the second direction is constituted irrevocably, the image forming apparatus according to any one of claims 1-8. The plurality of drum cartridges are
A first drum cartridge;
A first drum cartridge and a second drum cartridge adjacent to each other;
The first drum cartridge includes a first engagement portion,
The image forming apparatus according to claim 1, wherein the second drum cartridge includes a first engaged portion that can be engaged with the first engaging portion. . The first engaging portion has a convex shape protruding toward the second drum cartridge,
The image forming apparatus according to claim 10 , wherein the first engaged portion has a concave shape that can be engaged with the first engaging portion. The plurality of drum cartridges further includes a third drum cartridge adjacent to the second drum cartridge,
The second drum cartridge includes a second engaging portion,
The third drum cartridge includes a second engaged portion that can be engaged with the second engaging portion,
The second engaging portion and the second engaged portion are the first engaging portion, the first engaged portion, and the first direction when viewed from the second direction. wherein the are different position in the image forming apparatus according to claim 10 or 11. The second engagement portion has a convex shape protruding toward the third drum cartridge,
The image forming apparatus according to claim 12 , wherein the second engaged portion has a concave shape that can be engaged with the second engaging portion. Of the plurality of drum cartridges, the drum cartridge located on the most downstream side in the direction from the inner position to the outer position includes a third engagement portion,
The support includes a third engaged portion,
The third engaging portion and the third engaged portion are the first engaging portion, the first engaged portion, and the first direction when viewed from the second direction. wherein the are different position in the image forming apparatus according to any one of claims 10-13. The third engagement portion has a convex shape protruding toward the support,
The image forming apparatus according to claim 14 , wherein the third engaged portion has a concave shape that can be engaged with the third engaging portion. Said support is provided with a plurality of drum cartridges accommodating portion corresponding to each of the plurality of the drum cartridge,
Each of the plurality of drum cartridge accommodating portions includes a plurality of guide portions for guiding the corresponding drum cartridge,
Wherein the plurality of guide portions, characterized in that different arranged, an image forming apparatus according to any one of claims 1 to 15. The plurality of drum cartridges and the plurality of developing cartridges are configured to be detachable upward with respect to the support when the support is located at the outer position. The image forming apparatus according to any one of claims 1 to 16 . The belt unit includes a positioning portion that positions the plurality of drum cartridges,
The positioning unit, than the drum gripper, and being located inward of the first direction, the image forming apparatus according to any one of claims 1 to 17.   The device body;
  A plurality of drum cartridges having a photosensitive drum having an axis extending in the first direction; and a drum frame supporting the photosensitive drum, the drum frame having a drum gripping portion disposed at one end in the first direction; ,
  The plurality of drum cartridges that are movable in a second direction orthogonal to the first direction between an inner position in the apparatus main body and an outer position outside the apparatus main body, and are arranged in parallel in the second direction. A support configured to removably support the
With
  Each of the plurality of drum cartridges includes a mounting portion for stacking from above the drum cartridges other than the drum cartridge.
  Of the plurality of drum cartridges, the drum gripping portion of the drum cartridge other than the drum cartridge located at the most downstream in the direction from the inner position to the outer position is the front of the drum cartridge other than the drum cartridge. Can be engaged with the mounting portion,
  Among the plurality of drum cartridges, the drum gripping portion of the drum cartridge that is located on the most downstream side in the direction from the inner position toward the outer position engages with the placement portion of the drum cartridge other than the drum cartridge. An image forming apparatus, which is impossible.   Among the plurality of drum cartridges, the drum grip portion of the drum cartridge that is located on the most downstream side in the direction from the inner position to the outer position, and of the plurality of drum cartridges, the inner position to the outer position. The image forming apparatus according to claim 19, wherein the shape of the drum gripping portion of the drum cartridge other than the drum cartridge located at the most downstream in the direction of heading is different.   The mounting portion has a receiving groove that is recessed upward while the drum cartridge is supported by the support.
Of the plurality of drum cartridges, the drum gripping portion of the drum cartridge other than the drum cartridge located at the most downstream in the direction from the inner position to the outer position is the front of the drum cartridge other than the drum cartridge. Can fit into the receiving groove of the mounting portion,
  Among the plurality of drum cartridges, the drum gripping portion of the drum cartridge that is located on the most downstream side in the direction from the inner position toward the outer position is the reception of the placement portion of the drum cartridge other than the drum cartridge. 21. The image forming apparatus according to claim 19, wherein the image forming apparatus cannot fit into the groove.   A belt unit having a belt;
  The plurality of drum cartridges are disposed below the belt unit when the support body is positioned at the inner position in a state of supporting the plurality of drum cartridges. The image forming apparatus according to claim 1.

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