Image forming apparatus

Abstract

To provide an image forming apparatus that can reduce cost of the apparatus.SOLUTION: An image forming apparatus can be converted from a color machine to a monochrome machine by mounting only a black image forming unit and not mounting color image forming units. When used as the monochrome machine, the image forming apparatus is attached with a first monochrome inner cover 111 that is a single color inner cover that closes portions of an image forming unit mounting part where the color image forming units are mounted. The first monochrome inner cover 111 has receiving port closing parts 111a that close waste toner receiving ports corresponding to the color image forming units not mounted on the image forming apparatus, and prevents scattering of waste toner from the waste toner receiving port of the color machine.SELECTED DRAWING: Figure 12

Description

Technical Field

[0001] The present invention relates to an image forming apparatus.

Background Art

[0002] Conventionally, an image forming apparatus is known that includes an image forming unit mounting portion on which a plurality of image forming units for forming toner images of different colors are mounted, a plurality of waste toner receiving ports provided corresponding to each image forming unit for receiving waste toner discharged from the image forming unit, and a waste toner storage portion for storing the waste toner received at the waste toner receiving ports.

[0003] Patent Document 1 describes that, as the above-described image forming apparatus, a shutter member having an opening portion for opening the waste toner receiving port and a closing portion for closing the waste toner receiving port provided at each of the plurality of waste toner receiving ports is movably supported. The plurality of shutter members are configured to move the same amount simultaneously by a moving mechanism. The opening portion of the shutter member corresponding to the black (B) waste toner receiving port is longer on the downstream side in the rotation direction of the shutter member than the opening portions of the other shutter members (a plurality of shutter members corresponding to the yellow (Y), cyan (C), and magenta (M) waste toner receiving ports). Therefore, when the plurality of shutter members are simultaneously moved by the moving mechanism, the black (B) waste toner receiving port is opened by the opening portion of the shutter member earlier than the other waste toner receiving ports.

[0004] When using the above-described image forming apparatus as a monochrome machine, the Y, C, and M image forming units are not mounted, and only one B image forming unit is mounted on the B image forming unit mounting portion of the apparatus. Then, the moving amount of the shutter member by the moving mechanism is made smaller than the moving amount when using it as a color machine, only the B waste toner receiving port corresponding to the B image forming unit is opened, and it is described that the Y, C, and M waste toner receiving ports are closed with the shutter member.

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in Patent Document 1, it is necessary to provide shutter members at a plurality of waste toner receiving ports and a moving mechanism for moving these shutter members, which leads to a problem of cost increase due to an increase in the number of parts.

Means for Solving the Problems

[0006] In order to solve the above-described problems, the present invention provides an image forming apparatus including an image forming unit mounting portion on which a plurality of image forming units for forming toner images of different colors can be mounted, a plurality of waste toner receiving ports provided at respective image forming unit mounting locations of the image forming unit mounting portion for receiving waste toner discharged from the image forming units mounted on the image forming unit mounting portion, and a waste toner storage portion communicating with the plurality of waste toner receiving ports for storing the waste toner received by the waste toner receiving ports. When used as a monochromatic image forming apparatus for mounting one image forming unit on the image forming unit mounting portion to form a monochromatic image, the apparatus includes an inner cover attached to the apparatus main body, and the inner cover has a receiving port closing portion for closing the waste toner receiving port corresponding to the image forming unit that is not mounted.

Effects of the Invention

[0007] According to the present invention, an increase in the number of parts of the apparatus can be suppressed, and cost reduction can be achieved.

Brief Description of the Drawings

[0008]

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Embodiments for Carrying Out the Invention

[0009] Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. It should be noted that those skilled in the art can easily modify and change the present invention within the scope of the claims to form other embodiments, and these modifications and changes are included in the scope of the claims. The following description is an example of the best mode in this invention and does not limit the scope of the claims.

[0010] Hereinafter, as an image forming apparatus to which the present invention is applied, an electrophotographic image forming apparatus will be described. FIG. 1 is a schematic configuration diagram showing the configuration of the image forming apparatus 100 according to the present embodiment. In the figure, the Z direction is the vertical direction, the Y direction in the figure is the front-rear direction of the apparatus, and the X direction in the figure indicates the left-right direction of the apparatus.

[0011] The image forming apparatus 100 includes an image forming unit 3, a paper feeding unit 4 as a feeding means, an image reading device 2 for reading an image of a document to be image-formed, etc. The image reading device 2 is disposed above the image forming unit 3 and includes a document conveying unit 2a and a scanner unit 2b. The paper feeding unit 4 is disposed below the image forming unit 3 and includes two paper feeding cassettes 4a and 4b for accommodating transfer paper P.

[0012] The image forming unit 3 includes an intermediate transfer unit 15 having an intermediate transfer belt 6 as an intermediate transfer body, and four image forming units 5Y, 5M, 5C, and 5K for forming respective colors, and these are arranged along the intermediate transfer belt 6 that moves on the surface in the direction of arrow F in the figure. Each of the image forming units 5Y, 5M, 5C, and 5K has a photosensitive member 1Y, 1M, 1C, and 1K as a drum-shaped image carrier, respectively. Further, the image forming unit 3 includes an exposure device 7.

[0013] The intermediate transfer unit 15 includes an endless intermediate transfer belt 6 spanned over a plurality of support rollers, primary transfer rollers 8Y, 8C, 8M, 8K, a belt cleaning device 60 for cleaning the surface of the intermediate transfer belt 6, etc. The primary transfer rollers 8Y, 8M, 8C, 8K are disposed inside the intermediate transfer belt 6 and transfer a toner image from the photosensitive members 1Y, 1M, 1C, 1K onto the intermediate transfer belt 6. A secondary transfer roller 9 is provided on the downstream side in the surface movement direction of the intermediate transfer belt 6 with respect to the primary transfer rollers 8Y, 8M, 8C, 8K so as to face the surface of the intermediate transfer belt 6. Further, above the secondary transfer roller 9, a fixing device 10 for fixing the image on the transfer paper P and a paper discharge roller 11 are provided.

[0014] Since the four image forming units 5Y, 5M, 5C, and 5K have the same configuration except for the color of the toner they contain, the color - coding symbols will be omitted as appropriate in the following description. The image forming unit 5 includes, around the photoreceptor 1, a charging device that applies a charge to the surface of the photoreceptor 1, and a developing device that develops the latent image formed on the surface of the photoreceptor 1 with toner of each color to form a toner image. Further, a cleaning device for cleaning the surface of the photoreceptor 1 after the transfer of the toner image is arranged. The image forming unit 5 is configured to be detachable from the front side (-Y direction side) of the image forming apparatus 100.

[0015] Next, an operation example of the image forming apparatus 100 according to the present embodiment will be described. When receiving a signal for starting an image, the intermediate transfer belt 6 starts surface movement. At the same time, in the yellow image forming unit 5Y, the yellow photoreceptor 1Y is uniformly charged by a charging device and irradiated with laser light by an exposure device 7 to form an electrostatic latent image. The electrostatic latent image is developed by a developing device, and thereby a yellow toner image is formed on the yellow photoreceptor 1Y. Similarly, in the image forming units 5M, 5C, and 5K for other colors, magenta, cyan, and black toner images are respectively formed on the photoreceptors 1M, 1C, and 1K. Along with the surface movement of the intermediate transfer belt 6, the toner images of each color are sequentially transferred by the primary transfer rollers 8Y, 8M, 8C, and 8K, and a composite color image is formed on the intermediate transfer belt 6. Note that the image forming operations of each color are executed with the timings shifted from the upstream side to the downstream side in the surface movement direction of the intermediate transfer belt 6 so that the toner images are transferred and overlapped at the same position on the intermediate transfer belt 6.

[0016] On one hand, transfer paper P is fed from the upper paper feed cassette 4a or the lower paper feed cassette 4b, and is conveyed to a secondary transfer nip portion formed by the intermediate transfer belt 6 and the secondary transfer roller 9 which is a secondary transfer means. Then, the composite color image on the intermediate transfer belt 6 is transferred onto the transfer paper P by the secondary transfer roller 9, so that the color image is transferred onto the transfer paper P. The transfer paper P after image transfer is fed into a fixing device 10 which is a fixing means, and the transferred image is fixed onto the transfer paper P. The transfer paper P on which the fixing process has been performed in the fixing device 10 is stacked on the paper discharge tray 12 by a paper discharge roller 11 which is a discharge means, or is sent to the reverse path 13 to form a toner image on the other side, and one of the transport forms is selected.

[0017] Also, the residual toner on each photoreceptor 1Y, 1M, 1C, 1K after toner image transfer is cleaned by each cleaning device. Further, the residual toner on the intermediate transfer belt 6 after toner image transfer is cleaned by a belt cleaning device 60.

[0018] Also, for each developing device that has consumed toner by image formation, a predetermined supply amount of toner of each color is supplied from toner bottles 14Y, 14M, 14C, 14K filled with yellow, magenta, cyan, and black toners in the upper left of FIG. 1 through a toner conveyance path (not shown). Note that the arrangement order of the four image forming units 5Y, 5M, 5C, 5K and the toner bottles 14Y, 14M, 14C, 14K is not limited to the example shown in FIG. 1.

[0019] In the image forming apparatus 100 according to the present embodiment, when a copy of a document is taken, for example, a sheet-like document is set in a document conveyance unit 2a of the image reading device 2. After the document is set, when a copy start switch of an operation unit (not shown) is pressed, the operation of reading the document by the image reading device 2 starts. Specifically, the document is conveyed by the document conveyance unit 2a, and the conveyed document is read by the scanner unit 2b.

[0020] In parallel with this manuscript reading operation, each device within each image forming unit 5Y, 5M, 5C, 5K, the intermediate transfer belt 6, the secondary transfer roller 9, the fixing device 10, etc. start driving respectively. Then, based on the image information read by the image reading device 2, the exposure device 7 is driven and controlled, and Y, M, C, and K toner images are formed on each photoreceptor 1Y, 1M, 1C, 1K. These toner images become a four-color toner image that is superposed and transferred onto the intermediate transfer belt 6.

[0021] Also, almost simultaneously with the start of the manuscript reading operation, the paper feeding operation is started within the paper feeding unit 4. In this paper feeding operation, the transfer paper P is sent out from one of the paper feeding cassettes 4a, 4b that are stored in multiple stages. The sent-out transfer paper P is conveyed toward the secondary transfer nip.

[0022] The image forming apparatus 100 includes a waste toner conveying device 200 which is a waste toner conveying unit that conveys the waste toner of the cleaning devices of the image forming units 5Y, 5C, 5M, 5K and the waste toner of the belt cleaning device 60 to a waste toner container 18 which is a waste toner storage unit.

[0023] The waste toner conveying device 200 includes a first conveying unit 20 that conveys the waste toner of the cleaning devices of the image forming units 5Y, 5C, 5M, 5K, a second conveying unit 30 that conveys the waste toner of the belt cleaning device 60, and a waste toner connecting passage 23 through which the waste toner conveyed from the first conveying unit 20 and the second conveying unit 30 passes.

[0024] The first conveying unit 20 has waste toner inlets 21K, 21M, 21C, and 21Y for receiving waste toner conveyed from the cleaning devices of the image forming units 5Y, 5C, 5M, and 5K. The first conveying unit 20 is provided with a first waste toner conveying screw 22 for conveying the waste toner that has fallen from each waste toner inlet 21K, 21M, 21C, and 21Y in the left direction in the figure. The left end of the first conveying unit 20 in the figure is connected to a waste toner connection passage 23. The waste toner connection passage 23 is connected to the waste toner collection port of the waste toner container 18. That is, the waste toner container 18 communicates with the waste toner inlets 21K, 21M, 21C, and 21Y via the waste toner conveying device 200 (the first conveying unit 20 and the waste toner connection passage 23).

[0025] By rotating the first waste toner conveying screw 22, the waste toner in the first conveying unit 20 is conveyed to the left side in the figure. When it reaches the waste toner connection passage 23, it falls into the waste toner container 18 via the waste toner connection passage 23.

[0026] The second conveying unit 30 has a waste toner inlet 31 for receiving waste toner conveyed from a middle transfer waste toner conveying path 80 that conveys the waste toner of the belt cleaning device 60 provided in the intermediate transfer unit 15 at one end, and the other end is connected to the waste toner connection passage 23. That is, the waste toner container 18 communicates with the waste toner inlet 31 via the waste toner conveying device 200 (the second conveying unit 30 and the waste toner connection passage 23).

[0027] The middle transfer waste toner conveying path 80 has a waste toner conveying screw 82 inside. The waste toner conveyed by the cleaning conveying screw 62 of the belt cleaning device 60 is conveyed to the second conveying unit 30 by the waste toner conveying screw 82. The waste toner conveyed from the middle transfer waste toner conveying path 80 is transferred from the waste toner inlet 31 to the second conveying unit and is conveyed by falling inside the second conveying unit and reaches the waste toner connection passage 23. Then, it falls into the waste toner container 18 via the waste toner connection passage 23. Note that a conveying coil may be provided inside the second conveying unit 30, and the waste toner inside the second conveying unit may be conveyed to the waste toner connection passage 23 by the conveying coil.

[0028] FIG. 2 is a schematic front view of the image forming apparatus 100 with the front cover 100a opened. As shown in FIG. 2, four image forming units 5Y, 5C, 5M, 5K are mounted on the image forming unit mounting portion 130 of the image forming apparatus 100, and four toner bottles 14Y, 14M, 14C, 14K are mounted on the toner bottle mounting portion 140.

[0029] The image forming apparatus 100 also has an inner cover 121 for the first color and an inner cover 122 for the second color. The inner cover 121 for the first color covers the waste toner conveying device 200, the exposure device 7, etc., so that these are not exposed when the front cover 100a is opened. The inner cover 122 for the second color covers the fixing device 10, the secondary transfer roller 9, etc., so that these are not exposed when the front cover 100a is opened.

[0030] As shown in FIG. 2, when the front cover 100a is opened, the image forming units 5Y, 5M, 5C, 5K, the intermediate transfer unit 15, and the toner bottles 14Y, 14M, 14C, 14K are exposed. The image forming units 5Y, 5M, 5C, 5K can be attached to and detached from the main body of the image forming apparatus from the front side (-Y direction side) of the image forming apparatus by operating the operation lever 70. Similarly, the toner bottles 14Y, 14M, 14C, 14K can also be attached to and detached from the main body of the image forming apparatus from the front side (-Y direction side) of the image forming apparatus by releasing the lock by the user's operation. The intermediate transfer unit 15 can be pulled out to the front side (-Y direction side) by releasing the lock by the user's operation.

[0031] FIG. 3 is a perspective view showing the periphery of the operation lever 70, FIG. 4 is a plan view of the periphery of the operation lever 70, and FIG. 5 is a perspective view showing the state where the operation lever 70 is removed. As shown in FIG. 5, a shaft member 102 is fixed to the front frame 101 of the image forming apparatus main body. A female screw portion 102a is formed at the tip of the shaft member 102, and as shown in FIG. 3, a screw 103 is screwed into this female screw portion, so that the operation lever 70 is rotatably attached to the shaft member 102.

[0032] The operation lever 70 has a unit regulating portion 70a which is a lock portion for regulating the movement of the imaging unit 5 in the front side (-Y direction side) from the mounting position. The unit regulating portion 70a has a substantially fan shape that is opened approximately 90° in the rotation direction of the operation lever 70. Further, a protrusion 70b protruding toward the front frame 101 side (Y direction side) is provided at the rear end portion (front frame 101 side end portion) of the operation lever 70, and the tip of the protrusion 70b has a mountain shape.

[0033] As shown in FIG. 5, the tip of the shaft member 102 has a D-cut shape. The insertion hole into which the shaft member 102 of the operation lever 70 is inserted has a round hole shape, and the operation lever 70 is rotatably attached to the shaft member 102.

[0034] Further, a cam 71 is attached to the shaft member 102. The through hole through which the shaft member 102 of the cam 71 passes has a D-shaped cross section. The cam 71 is attached to the shaft member 102 so as to be movable in the axial direction of the shaft member 102 and non-rotatable, and the operation lever 70 is relatively rotatable with respect to the cam 71. The operation lever side end portion of the cam 71 has a valley and mountain shape. The uppermost part of the cam 71 in the vertical direction (Z direction) is the bottom of the valley. From there, the top of the mountain is located at a position approximately 90° in the counterclockwise rotation direction in the figure of FIG. 5, and from there, a position rotated approximately 60° counterclockwise in the figure (a position diagonally upward to the left from the lowermost part of the cam 71 in the vertical direction (Z direction)) is the bottom of the valley having a large step.

[0035] Further, a cam spring 72 is attached to the shaft member 102. The cam spring 72 is attached in a compressed state between the cam 71 and the front frame 101, and biases the cam 71 toward the operation lever 70 side.

[0036] As shown in FIGS. 3 and 4, when the operation lever 70 is positioned at the lock position for locking the image forming unit 5 in a posture parallel to the vertical direction (Z direction), the top of the protrusion 70b is positioned at the bottom of the valley which is the uppermost part in the vertical direction (Z direction) of the cam 71. Thus, when moving the operation lever 70 from the lock position to the unlock position, it is necessary for the top of the protrusion 70b to climb up the inclined surface of the cam 71 against the biasing force of the cam spring 72. Therefore, when hitting the operation lever 70, a force is generated to rotate the operation lever 70 in the unlocking direction, and even if the operation lever 70 rotates slightly, the operation lever 70 can be returned to the lock position by the biasing force of the cam spring 72. Thereby, the locking of the image forming unit 5 can be maintained.

[0037] FIG. 6 is a schematic perspective view showing the front side of the image forming unit 5C. In the following description, the image forming unit 5C will be described, but the image forming units 5Y, 5M, and 5K have the same configuration. As shown in FIG. 6, the front cover 50a of the image forming unit 5C has a first restricting portion 50b for restricting the clockwise rotation of the operation lever 70 in the figure, and a second restricting portion 50c for restricting the counterclockwise rotation of the operation lever 70 in the figure. The first restricting portion 50b abuts against the operation lever 70 to restrict the clockwise rotation of the operation lever 70 from the lock position in the figure. The second restricting portion 50c abuts against the unit restricting portion 70a to restrict the counterclockwise rotation of the operation lever 70 from the unlock position in the figure.

[0038] Also, when the operation lever 70 is positioned at the lock position for locking the image forming unit 5C at the mounting position as shown in FIG. 6, the unit restricting portion 70a abuts against the front cover 50a to restrict the movement of the image forming unit 5C in the front side (-Y direction side).

[0039] FIG. 7 is a diagram for explaining the operation of the operation lever 70. When unlocking, rotate the operation lever 70 located at the lock position shown in Fig. 7(a) counterclockwise in the figure. Then, as shown in Figs. 3 to 5, against the biasing force of the cam spring 72, while pushing the cam 71 backward (toward the front frame 101 side), the top of the peak of the protrusion 70b climbs up the inclined surface of the cam.

[0040] As shown in Fig. 7(b), when the operation lever 70 is rotated counterclockwise in the figure by approximately 90° from the lock position, the top of the peak of the protrusion 70b of the operation lever reaches the top of the peak of the cam 71. When the operation lever 70 is further rotated counterclockwise in the figure and the top of the peak of the protrusion 70b exceeds the top of the peak of the cam 71, the biasing force of the cam spring 72 changes from the force that hinders the rotation of the operation lever 70 (the force that rotates it to the lock position) to the force that rotates the operation lever 70 (the force that rotates it to the unlock position). As a result, the load of the rotation of the operation lever 70 suddenly decreases, and the operator of the operation lever 70 can obtain a click feeling. When the operator releases the hand from the operation lever 70 when obtaining the click feeling, the operation lever 70 automatically rotates counterclockwise in the figure due to the biasing force of the cam spring 72. Then, as shown in Fig. 7(c), when the operation lever 70 rotates approximately 150° and the operation lever 70 is located at the unlock position, the downstream end in the rotation direction of the peak of the protrusion 70b of the operation lever 70 (see Figs. 3 and 4) abuts against the step of the valley of the cam 71 (the top of the peak of the protrusion 70b of the operation lever 70 is located at the bottom of the lower valley of the cam 71). Thereby, the rotation of the operation lever 70 due to the biasing force of the cam spring 72 stops, and the operation lever 70 remains at the unlock position.

[0041] As shown in Fig. 7(c), when the operation lever 70 is located at the unlock position, the entire operation lever 70 including the unit regulating portion 70a no longer faces the imaging unit 5C in the Y direction, and the imaging unit 5C can be pulled out toward the front side (-Y direction side).

[0042] Also, as shown in FIG. 7(c), when the operation lever 70 is in the unlocked position, the counterclockwise downstream end of the unit regulating portion 70a in the drawing faces the second regulating portion 50c provided on the front cover 50a of the imaging unit 5C. Thereby, the counterclockwise rotation of the operation lever 70 from the unlocked position in the drawing is regulated by the second regulating portion 50c, and the operation lever 70 can be positioned at the unlocked position.

[0043] Also, at the unlocked position of FIG. 7(c) as well, the top of the peak of the protrusion 70b of the operation lever is located at the bottom of the valley of the cam 71. Therefore, even if the operation lever rotates clockwise to some extent by hitting the operation lever 70, the urging force of the cam spring 72 can return the operation lever 70 to the unlocked position.

[0044] When locking the imaging unit 5C in the mounting position, the operator rotates the operation lever 70 located at the unlocked position clockwise in the drawing. Then, near FIG. 7(b), when the top of the peak of the protrusion 70b crosses the top of the peak of the cam, the urging force of the cam spring 72 switches from the force that prevents the clockwise rotation of the operation lever 70 (rotates it to the unlocked position) to the force that rotates the operation lever 70 clockwise in the drawing (rotates it to the locked position). Thereby, a click feeling can be given to the operator. Also, thereafter, the operation lever 70 can be rotated by the urging force of the cam spring 72 without the operation of the operator, and the operation lever 70 can be automatically positioned at the locked position.

[0045] FIG. 8 is a cross-sectional view taken along line A-A of FIG. 2, and FIG. 9 is a cross-sectional view taken along line B-B of FIG. 8. In the following description, the imaging unit 5C will be described, but the imaging units 5Y, 5M, and 5K have the same configuration. As shown in FIG. 9, the waste toner conveying screw 53 of the cleaning device of the image forming unit 5C extends into the waste toner conveying path 51 that conveys the waste toner of the cleaning device. At the end of this waste toner conveying path 51, a waste toner dropping path 52 is connected. A swing member 54 is disposed in the waste toner dropping path 52, and the swing member 54 is attached to an eccentric shaft portion 53a at the front side (-Y direction side) end of the waste toner conveying screw 53. Thereby, as the waste toner conveying screw 53 rotates, the swing member 54 moves up and down in the vertical direction (Z direction) within the waste toner dropping path 52. As a result, the free fall of the waste toner can be promoted, and toner aggregation within the waste toner dropping path 52 can be prevented.

[0046] At the lower end of the waste toner dropping path 52, a shutter mechanism 40 for opening and closing the waste toner discharge port 52a of the waste toner dropping path 52 is provided. The shutter mechanism 40 includes a shutter member 41 and a compression spring 42. The shutter member 41 is supported by the waste toner dropping path 52 so as to be movable in the front-rear direction (±Y direction) of the image forming apparatus, and at its rear side (Y direction side) end, it has a biasing force receiving portion 41b that extends upward and receives the biasing force of the compression spring 42. Further, the shutter member 41 is provided with an opening 41a for opening the waste toner discharge port 52a.

[0047] The compression spring 42 is engaged with a protruding spring receiver 52b provided on the outer peripheral surface of the waste toner dropping path 52, and is compressed by the outer peripheral surface of the waste toner dropping path 52 and the biasing force receiving portion 41b of the shutter member 41.

[0048] When the image forming unit 5C is mounted on the image forming unit mounting portion 130 of the main body of the image forming apparatus, the shutter member 41 abuts against the front frame 101 of the image forming apparatus. Further, as the image forming unit 5C is mounted, the shutter member 41 moves relatively toward the front side (-Y direction side) of the image forming apparatus with respect to the image forming unit 5C against the biasing force of the compression spring 42. Then, when the image forming unit 5C moves to the mounting position, the waste toner discharge port 52a of the waste toner dropping path 52 overlaps with the waste toner receiving port 21C of the first conveying unit 20. Further, the opening 41a of the shutter member 41 is located at a position overlapping the waste toner discharge port 52a to open the waste toner discharge port 52a. As a result, the waste toner of the cleaning device falls from the waste toner discharge port 52a to the waste toner receiving port 21C through the waste toner discharge port 52a and is discharged from the image forming unit 5C.

[0049] When the image forming unit 5C is mounted on the image forming unit mounting portion 130 and the shutter member 41 is located at the open position, the image forming unit 5C is biased toward the front side (-Y direction side) of the image forming apparatus by the compression spring 42. However, the image forming unit 5C has a weight and a large frictional force with the portion that supports the image forming unit 5C of the apparatus main body. Therefore, the image forming unit 5C does not move toward the front side (-Y direction side) by the biasing force of the compression spring 42. Even if the image forming unit 5C attempts to move toward the front side (-Y direction side) by the biasing force of the compression spring 42, the movement of the image forming unit 5C toward the front side (-Y direction side) is restricted by the unit restricting portion 70a provided on the operation lever 70 described above. Therefore, the image forming unit can be positioned at the mounting position.

[0050] The opening 41a of the shutter member 41 and the waste toner receiving port 21C are larger than the waste toner discharge port 52a of the waste toner dropping path 52, suppressing the adhesion of waste toner to the shutter member 41. Further, an elastic member 24C made of a sponge or the like is provided at the edge of the waste toner receiving port 21C, and the elastic member 24C surrounds the waste toner receiving port 21C. When the image forming unit 5C is mounted on the image forming apparatus main body, this elastic member 24C is compressed and adheres closely to the shutter member 41. Thereby, good sealing performance is ensured, preventing waste toner from scattering into the image forming apparatus main body and preventing the contamination of the image forming apparatus main body.

[0051] The image forming apparatus 100 of the present embodiment can be diverted as a monochrome machine without mounting the color image forming units 5Y, 5M, 5C, aiming to make the components, systems, and functions common between the color machine and the monochrome machine. Specifically, the intermediate transfer unit 15 as intermediate transfer means, the secondary transfer roller 9 as secondary transfer means, the fixing device 10 as fixing means, the paper feeding unit 4 as feeding means, the paper discharging roller 11 as discharging means, etc. are made common between the color machine and the monochrome machine. In this way, by diverting as a monochrome machine without mounting the color image forming units 5Y, 5M, 5C and making many components common between the color machine and the monochrome machine, it is possible to reduce the newly invested resources and reduce the cost of the apparatus. Also, the recyclability from the color machine to the monochrome machine and from the monochrome machine to the color machine can be enhanced.

[0052] When diverting as a monochrome machine without mounting the color image forming units 5Y, 5M, 5C, the color waste toner receiving ports 21Y, 21M, 21C remain open, and there is a risk that waste toner scatters from these color waste toner receiving ports 21Y, 21M, 21C and contaminates the inside of the image forming apparatus main body.

[0053] Therefore, conventionally, when used as a monochrome machine, the waste toner inlets 21Y, 21M, and 21C for each color were sealed with a sealing member. However, when changing from a color machine to a monochrome machine or from a monochrome machine to a color machine, problems such as the need to attach and remove the sealing parts to the waste toner inlets 21Y, 21M, and 21C for each color and an increase in the working hours occurred. In addition, some have a shutter mechanism for opening and closing the waste toner inlet on the main body side of the image forming apparatus, but there is a risk of increasing costs due to an increase in the number of parts.

[0054] Therefore, in this embodiment, an inner cover for a monochrome machine is provided, and the inner cover is used to block the waste toner inlets 21Y, 21M, and 21C for each color. Hereinafter, it will be specifically described with reference to the drawings.

[0055] FIG. 10 is a schematic configuration diagram showing the configuration of an image forming apparatus 100 used as a monochrome machine, and FIG. 11 is a schematic front view of the image forming apparatus 100 used as a monochrome machine with the front cover 100a opened. As shown in FIGS. 10 and 11, when used as a monochrome machine, only the image forming unit 5K is mounted on the image forming unit mounting portion 130, and only the toner bottle 14K is mounted on the toner bottle mounting portion 140. Further, when used as a monochrome machine, as shown in FIG. 11, a first monochrome inner cover 111, which is a monochrome inner cover for single color, and a second monochrome inner cover 112 are attached.

[0056] The first monochrome inner cover 111 covers the waste toner conveying device 200, the exposure device 7, etc. in the same manner as the first color inner cover 121, and further covers the locations where the color image forming units 5Y, 5M, and 5C of the image forming unit mounting portion 130 are mounted. In addition, the first monochrome inner cover 111 is provided with three inlet closing portions 111a for closing the waste toner inlets 21Y, 21M, and 21C for each color.

[0057] The inner cover 112 for the second monochrome covers the fixing device 10, the secondary transfer roller 9, etc., in the same way as the inner cover 122 for the second color. Further, the inner cover 112 for the second monochrome also covers the locations where the color toner bottles 14Y, 14M, and 14C of the toner bottle mounting portion 140 are mounted.

[0058] FIG. 12 is a cross-sectional view taken along the line C-C of FIG. 11, and FIG. 13 is a cross-sectional view taken along the line D-D of FIG. 12. In the following description, the receptacle closing portion 111a that closes the waste toner receptacle 21C will be described, but the other receptacle closing portions 111a have the same configuration. The receptacle closing portion 111a has a hollow rectangular columnar concave shape recessed toward the inside (Y-direction side) of the image forming apparatus, and as shown in FIGS. 12 and 13, it is in close contact with the elastic member 24C provided at the edge of the waste toner receptacle 21C to close the waste toner receptacle 21C. Thereby, it is possible to prevent the waste toner from scattering from the waste toner receptacle 21C and prevent the inside of the image forming apparatus from being soiled with the waste toner.

[0059] Also, when recycling from a color machine to a monochrome machine, it is only necessary to replace the inner cover for the first color with the inner cover 111 for the first monochrome to close the waste toner receptacles 21Y, 21M, and 21C of the three colors. In this way, it is possible to close the waste toner receptacles 21Y, 21M, and 21C of the three colors only by replacing a single member. Therefore, compared with the method of attaching a sealing member to each of the waste toner receptacles 21Y, 21M, and 21C of each color to close them, it is possible to easily convert from a color machine to a monochrome machine.

[0060] Also, it is possible to close the waste toner receptacles 21Y, 21M, and 21C of the three colors with a single member of the inner cover 111 for the first monochrome. Thereby, compared with the case where a shutter mechanism is provided for each of the waste toner receptacles 21Y, 21M, and 21C of the three colors to close the waste toner receptacles 21Y, 21M, and 21C of the colors, the number of parts can be reduced, and the cost of the image forming apparatus can be reduced.

[0061] Also, as shown in FIG. 13, the inner cover 111 for the first monochrome has a concave fastening portion 111b formed with a through-hole through which the screw 103 penetrates at the center. This fastening portion 111b is screwed to the shaft member 102 to which the operation lever 70 is screwed by the screw 103. In this way, the shaft member 102 can be shared by the color unit and the monochrome unit, further reducing resources and reducing the cost of the image forming apparatus.

[0062] Also, as shown in FIG. 13, by screwing the inner cover 111 for the first monochrome to the shaft member 102, the inner cover 111 for the first monochrome can be fastened to the main body of the image forming apparatus near the waste toner receiving port 21C. In this way, by fastening the inner cover 111 for the first monochrome to the apparatus main body near the waste toner receiving port 21C, deformation near the receiving port closing portion 111a due to the reaction force of the elastic member 24C that is compression-deformed and warping near the receiving port closing portion 111a can be suppressed. Thereby, generation of a gap between the elastic member 24C and the receiving port closing portion 111a can be suppressed, and generation of toner scattering can be suppressed.

[0063] The inner cover 111 for the first monochrome is a resin molded product in which the fastening portion 111b and the receiving port closing portion 111a are integrally molded. By integrally molding the fastening portion 111b and the receiving port closing portion 111a, the number of parts can be reduced and the cost of the image forming apparatus can be reduced.

[0064] By forming the receiving port closing portion 111a in a concave shape, the thickness of the inner cover 111 for the first monochrome can be made uniform, and molding defects such as sink marks can be suppressed. As shown in FIG. 12, the opposing surface 111a-2 facing the contact surface 111a-1 that contacts the elastic member 24C of the concave receiving port closing portion 111a is an inclined surface such that the distance from the contact surface 111a-1 decreases as it goes to the bottom of the receiving port closing portion 111a (the inner side end portion of the image forming apparatus), forming a draft angle. Thereby, the mold release property of the inner cover 111 for the first monochrome can be enhanced.

[0065] Also, as shown in FIG. 14, the first monochrome inner cover 111 may be composed of a plurality of members, i.e., a first member 211 and a second member 212. The first member 211 is a resin molded product in which a fastening portion 111b (see FIG. 13) and a receiving port closing portion 111a are integrally molded, and it covers the locations where the color image forming units 5Y, 5M, and 5C of the image forming unit mounting portion 130 are mounted. The second member 212 covers the toner conveyance device 200, the exposure device 7, etc., and the first member 211 is engaged with the second member 212 by screws or the like.

[0066] With the configuration shown in FIG. 14, the second member 212 can be used as the first color inner cover 121, and the cost of the image forming apparatus can be reduced.

[0067] Also, the first member 211 may be configured to cover one of the locations where the three color image forming units 5Y, 5M, and 5C of the image forming unit mounting portion 130 are mounted, and the second member 212 may be configured such that a plurality of first members 211 can be attached. In such a configuration, the inner cover can be customized according to the number of image forming units to be removed. For example, when removing the color image forming units 5Y, 5M, and 5C and using it as a monochrome machine, as shown in FIG. 15, by attaching the three first members 211 to the second member 212, a monochrome inner cover can be formed. As shown in FIG. 16, when removing the C-color image forming unit and using it as a three-color image forming apparatus, by attaching one first member 211 to the second member 212, a three-color inner cover can be formed. Also, when removing two image forming units of C color and M color and replacing the Y-color image forming unit 5Y with a red image forming unit and using it as a two-color image forming apparatus of red and black, by attaching two first members 211 to the second member 212, a two-color inner cover can be formed. When using it as a color machine, by not attaching any first member 211 to the second member 212, a color inner cover can be formed. Thereby, resource reduction can be achieved. Also, the recyclability can be enhanced, and the cost of the image forming apparatus can be reduced.

[0068] The three first members 211 shown in FIG. 15 have the same shape, and the first member 211 can cover any of the three locations where the color image forming units 5Y, 5M, and 5C of the image forming unit mounting portion 130 are mounted. Thereby, further resource reduction can be achieved, recyclability can be improved, and cost reduction of the image forming apparatus can be achieved.

[0069] Also, it is preferable that the first member 211 is configured to be detachable from the image forming apparatus main body with the second member 212 attached to the image forming apparatus main body. Thereby, for example, when recycling from a monochrome machine to a color machine or from a color machine to a monochrome machine, it becomes possible to perform the work without removing the second member 212 from the image forming apparatus. Thereby, the recyclability workability of the image forming apparatus can be improved.

[0070] As described above, the preferred embodiments of the present invention have been described. However, the present invention is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims, unless otherwise specifically limited in the above description. For example, a waste toner container 18 provided with waste toner inlets 21Y, 21M, 21C, and 21K may be used, and a configuration may be adopted in which the waste toner of each image forming unit 5Y, 5M, 5C, and 5K directly falls into the waste toner container 18, and the waste toner conveying device is eliminated.

[0071] Also, for example, when used as a monochrome machine, an inner cover that covers only the locations where the color toner bottles 14Y, 14M, and 14C of the toner bottle mounting portion 140 are mounted may be attached to the apparatus main body, and the second color inner cover 122 may be made common between the monochrome machine and the color machine. Also, a configuration may be adopted in which three inner covers that cover one of the three locations where the color toner bottles of the toner bottle mounting portion 140 are mounted are attached to the second color inner cover 122.

[0072] What has been described above is an example, and specific effects are exhibited for each of the following aspects. (Aspect 1) In an image forming apparatus 100 including an image forming unit mounting portion 130 to which a plurality of image forming units 5Y, 5M, 5C, 5K for forming toner images of different colors can be mounted, a plurality of waste toner receiving ports 21Y, 21M, 21C, 21K provided at respective image forming unit mounting locations of the image forming unit mounting portion 130 for receiving waste toner discharged from the image forming units mounted on the image forming unit mounting portion 130, and a waste toner storage portion such as a waste toner container 18 communicating with the plurality of waste toner receiving ports and storing the waste toner received at the waste toner receiving ports, when used as a monochromatic image forming apparatus such as a monochrome machine that mounts one image forming unit 5K on the image forming unit mounting portion 130 to form a monochromatic image, it includes an inner cover such as a first monochrome inner cover 111 attached to the apparatus main body. The inner cover has a receiving port closing portion 111a that closes the waste toner receiving ports 21Y, 21C, 21M corresponding to the non-mounted image forming units. According to this, when the image forming apparatus is used as a monochromatic image forming apparatus, the waste toner receiving ports corresponding to the non-mounted image forming units can be closed by a member of the monochromatic inner cover. Thereby, compared with Patent Document 1, the number of parts can be reduced, and the cost of the apparatus can be reduced.

[0073] (Aspect 2) In an image forming apparatus 100 including an image forming unit mounting portion 130 to which a plurality of image forming units 5Y, 5M, 5C, 5K for forming toner images of different colors can be mounted, a plurality of waste toner receiving ports 21Y, 21M, 21C, 21K provided at respective image forming unit mounting locations of the image forming unit mounting portion 130 for receiving waste toner discharged from the image forming units mounted on the image forming unit mounting portion 130, and a waste toner storage portion such as a waste toner container 18 communicating with the plurality of waste toner receiving ports and storing the waste toner received at the waste toner receiving ports, it includes an inner cover that covers at least the location where the image forming unit of the image forming unit mounting portion 130 is not mounted. The inner cover has a receiving port closing portion 111a that closes the waste toner receiving ports corresponding to the non-mounted image forming units. According to this, when the image forming apparatus is used as a monochromatic image forming apparatus, the waste toner receiving port corresponding to the image forming unit that is not mounted can be blocked by a member of the inner cover. As a result, compared with Patent Document 1, the number of components can be reduced, and the cost of the apparatus can be reduced.

[0074] (Aspect 3) In Aspect 2, the inner cover includes a receiving port closing portion 111a, and is composed of a first member 211 that covers a location where the image forming unit is not mounted, and a second member 212 with which the first member 211 engages. The first member 211 is detachable from the apparatus main body when the second member 212 is attached to the apparatus main body. According to this, when there is no location where the image forming unit is not mounted in the image forming unit mounting portion 130 as described with reference to FIGS. 14 to 16, only the second member 212 is attached to the image forming apparatus main body. When there is a location where the image forming unit is not mounted in the image forming unit mounting portion 130, the first member is attached so as to cover that location, and the waste toner receiving port corresponding to the image forming unit that is not mounted can be blocked by the receiving port closing portion 111a of the first member.

[0075] (Aspect 4) In Aspect 3, the first member 211 covers one location where the image forming unit is not mounted in the image forming unit mounting portion 130, and the second member 212 can engage with a plurality of first members 211. According to this, only one location where the image forming unit is not mounted in the image forming unit mounting portion 130 is covered by the first member 211, and the waste toner receiving port corresponding to the image forming unit that is not mounted can be blocked by the receiving port closing portion 111a of the first member. Thus, as shown in FIG. 15, when used as a monochromatic machine with only one of the four image forming units mounted, or as shown in FIG. 16, when used as a two-color machine with two to three image forming units mounted, the waste toner receiving port corresponding to the image forming unit that is not mounted can be blocked by the receiving port closing portion 111a of the first member.

[0076] (Aspect 5) In Mode 4, the plurality of first members have the same shape. According to this, as described with reference to FIGS. 15 and 16, the covering position is not limited, and any of the plurality of mounting positions of the image forming unit mounting portion 130 can be covered with the first member 211.

[0077] (Mode 6) In any of Modes 1 to 5, elastic members 24Y, 24C, 24M, and 24K are provided at the edges of the waste toner receiving ports 21Y, 21C, 21M, and 21K, and the receiving port closing portion 111a is in close contact with the elastic members 24Y, 24C, 24M to close the waste toner receiving ports 21Y, 21C, 21M. According to this, as described in the embodiment, the waste toner receiving ports 21Y, 21C, 21M can be closed without gaps, and toner scattering from the waste toner receiving ports 21Y, 21C, 21M can be preferably suppressed.

[0078] (Mode 7) In any of Modes 1 to 6, an inner cover such as the first monochrome inner cover 111 is fastened to the apparatus housing near the receiving port closing portion. According to this, as described in the embodiment, deformation near the receiving port closing portion 111a due to the reaction force of the elastically deformed elastic member 24C and warping near the receiving port closing portion 111a can be suppressed. Thereby, generation of a gap between the elastic member and the receiving port closing portion 111a can be suppressed, and generation of toner scattering can be suppressed.

[0079] (Mode 8) In Mode 7, an inner cover such as the first monochrome inner cover 111 is fastened to a shaft member 102 to which an operation lever 70 for operating a locking portion such as a unit regulating portion 70a for locking the image forming unit in the mounted state is fastened. According to this, as described in the embodiment, the shaft member 102 can be shared between the color machine and the monochrome machine, further resource reduction can be achieved, and cost reduction of the apparatus can be achieved.

[0080] (Mode 9) In any one of Aspects 1 to 8, the receiving port closing portion 111a is integrally formed with the inner cover. According to this, compared with the case where the receiving port closing portion 111a is a separate component, the number of components can be reduced, and cost reduction can be achieved.

[0081] (Aspect 10) In Aspect 9, the receiving port closing portion 111a is integrally formed with a member that covers a location where an imaging unit such as the first member 211 of the inner cover is not mounted. According to this, compared with the case where the receiving port closing portion 111a is a separate component, the number of components can be reduced, and cost reduction can be achieved.

[0082] (Aspect 11) In Aspect 9 or 10, a fastening portion 111b that is fastened to the apparatus housing in the vicinity of the receiving port closing portion 111a of the inner cover is integrally formed with the inner cover. According to this, the number of components can be reduced, and cost reduction can be achieved.

[0083] (Aspect 12) In any one of Aspects 9 to 11, the receiving port closing portion 111a has a concave shape that is recessed from the main body portion of the inner cover toward the inside of the image forming apparatus. According to this, the thickness of the inner cover can be made uniform, molding defects in the integral molding can be suppressed. Also, reduction of material costs can be achieved.

[0084] (Aspect 13) In Aspect 12, a facing surface 111a - 2 that faces a contact surface 111a - 1 that contacts the waste toner receiving port of the concave - shaped receiving port closing portion 111a is an inclined surface whose distance from the contact surface 111a - 1 decreases as it approaches the bottom of the concave - shaped receiving port closing portion. According to this, the releasability from the mold for molding the concave - shaped receiving port closing portion 111a of the inner cover can be enhanced.

[0085] (Aspect 14) In any of Aspects 1 to 13, there is a waste toner conveying unit such as a waste toner conveying device 200 that conveys the waste toner received at the waste toner inlets 21Y, 21C, 21M, and 21K to a waste toner storage unit such as a waste toner container 18. According to this, as described in the embodiment, the waste toner received at each of the waste toner inlets 21Y, 21C, 21M, and 21K can be stored in the waste toner container 18.

[0086] (Aspect 15) In any of Aspects 1 to 14, intermediate transfer means such as an intermediate transfer unit 15 including an intermediate transfer body such as an intermediate transfer belt 6 on which a toner image formed by an image forming unit is intermediate transferred, secondary transfer means such as a secondary transfer roller 9 that transfers the toner image on the intermediate transfer body to a sheet, fixing means such as a fixing device 10 that fixes the toner image transferred to the sheet, feeding means such as a paper feeding unit 4 that feeds the sheet toward the secondary transfer means, and discharging means such as a paper discharging roller 11 that discharges the sheet outside the apparatus are common whether used as a monochrome image forming apparatus such as a monochrome machine or as a color image forming apparatus such as a color machine that mounts a plurality of image forming units on an image forming unit mounting portion 130 to form a color image. According to this, as described in the embodiment, by making many components common between a color image forming apparatus such as a color machine and a monochrome image forming apparatus such as a monochrome machine, it is possible to reduce newly invested resources and reduce the cost of the apparatus. Also, the recyclability from a color image forming apparatus to a monochrome image forming apparatus and from a monochrome image forming apparatus to a color image forming apparatus can be enhanced.

Explanation of Reference Numerals

[0087] 1: Photoconductor 4: Paper feeding unit 5: Image forming unit 6: Intermediate transfer belt 9: Secondary transfer roller 10: Fixing device 11: Paper discharging roller 15: Intermediate transfer unit 18: Waste toner container 20: First conveying unit 21: Waste toner inlet 22: First waste toner conveying screw 23: Waste toner connection path 24: Elastic member 30: Second conveying unit 31: Waste toner inlet 40: Shutter mechanism 41: Shutter member 41a: Opening 41b: Biasing force receiving part 42: Compression spring 51: Waste toner conveying path 52: Waste toner dropping path 52a: Waste toner discharge port 52b: Spring receiver 53: Waste toner conveying screw 53a: Eccentric shaft part 54: Rocking member 60: Belt cleaning device 62: Cleaning conveying screw 70: Operating lever 70a: Unit regulating part 70b: Protrusion 71: Cam 72: Cam spring 80: Intermediate waste toner conveying path 82: Waste toner conveying screw 100: Image forming apparatus 100a: Front cover 101: Front frame 102: Rotating shaft 103: Screw 111: First monochrome inner cover 111a: Inlet closing part 111b: Fastening part 112: Second monochrome inner cover 121: First color inner cover 122: Second color inner cover 130: Image forming unit mounting part 140: Toner bottle mounting part 200: Waste Toner Conveyor 211: First Member 212: Second Member P: Transfer Paper

Prior Art Documents

Patent Documents

[0088]

Patent Document 1

Claims

1. An image forming apparatus including an image forming unit mounting portion on which a plurality of image forming units for forming toner images of different colors can be mounted, a plurality of waste toner receiving ports provided respectively at each image forming unit mounting location of the image forming unit mounting portion for receiving waste toner discharged from the image forming unit mounted on the image forming unit mounting portion, and a waste toner storage portion communicating with the plurality of waste toner receiving ports for storing the waste toner received by the waste toner receiving ports. When used as a monochrome image forming apparatus in which one image forming unit is mounted on the image forming unit mounting portion to form a monochrome image, it is provided with an inner cover attached to the apparatus main body, wherein the inner cover has a receiving port closing portion for closing the waste toner receiving port corresponding to the unmounted image forming unit.

2. An image forming apparatus including an image forming unit mounting portion on which a plurality of image forming units for forming toner images of different colors can be mounted, a plurality of waste toner receiving ports provided respectively at each image forming unit mounting location of the image forming unit mounting portion for receiving waste toner discharged from the image forming unit mounted on the image forming unit mounting portion, and a waste toner storage portion communicating with the plurality of waste toner receiving ports for storing the waste toner received by the waste toner receiving ports. It is provided with an inner cover that covers at least the portion where the image forming unit of the image forming unit mounting portion is not mounted, wherein the inner cover has a receiving port closing portion for closing the waste toner receiving port corresponding to the unmounted image forming unit.

3. In the image forming apparatus according to Claim 2, the inner cover has the receiving port closing portion and is composed of a first member that covers the portion where the image forming unit is not mounted and a second member with which the first member engages, wherein the first member is detachable from the apparatus main body with the second member attached to the apparatus main body.

4. In the image forming apparatus according to Claim 3, the first member covers one portion where the image forming unit of the image forming unit mounting portion is not mounted, wherein the second member allows a plurality of first members to engage therewith.

5. In the image forming apparatus according to Claim 4, the plurality of first members have the same shape.

6. In the image forming apparatus according to Claim 1 or 2, ​ ​ An elastic member is provided so as to surround each waste toner receiving port. The image forming apparatus is characterized in that the receiving port closing portion closes the waste toner receiving port in close contact with the elastic member. **Claim 7** In the image forming apparatus according to claim 6, the image forming apparatus is characterized in that the inner cover is fastened to the apparatus housing in the vicinity of the receiving port closing portion. **Claim 8** In the image forming apparatus according to claim 7, the image forming apparatus is characterized in that the inner cover is fastened to a shaft member to which an operation lever for operating a locking portion for locking the image forming unit located at the mounting position is fastened. **Claim 9** In the image forming apparatus according to claim 1 or 2, the image forming apparatus is characterized in that the receiving port closing portion is integrally formed with the inner cover. **Claim 10** In the image forming apparatus according to claim 9, the image forming apparatus is characterized in that the receiving port closing portion is integrally formed with a member that covers a portion of the inner cover where the image forming unit is not mounted. **Claim 11** In the image forming apparatus according to claim 9, the image forming apparatus is characterized in that a fastening portion fastened to the apparatus housing in the vicinity of the receiving port closing portion of the inner cover is integrally formed with the inner cover. **Claim 12** In the image forming apparatus according to claim 9, the image forming apparatus is characterized in that the receiving port closing portion has a concave shape recessed from the main body portion of the inner cover toward the inside of the image forming apparatus. **Claim 13** In the image forming apparatus according to claim 12, the image forming apparatus is characterized in that a facing surface facing a contact surface that contacts the waste toner receiving port of the receiving port closing portion having a concave shape is an inclined surface whose distance from the contact surface decreases as it approaches the bottom of the receiving port closing portion having a concave shape. **Claim 14** In the image forming apparatus according to claim 1 or 2, the image forming apparatus is characterized by having a waste toner conveying unit that conveys the waste toner received at the waste toner receiving port to the waste toner storage unit. **Claim 15** In the image forming apparatus according to claim 1 or 2, An image forming apparatus comprising intermediate transfer means having an intermediate transfer body onto which a toner image formed by the image forming unit is intermediate-transferred, secondary transfer means for transferring the toner image on the intermediate transfer body onto a sheet, fixing means for fixing the toner image transferred onto the sheet, feeding means for feeding the sheet toward the secondary transfer means, and discharging means for discharging the sheet outside the apparatus, characterized in that it is common when used as a monochrome image forming apparatus for mounting one image forming unit on the image forming unit mounting portion to form a monochrome image, and when used as a color image forming apparatus for mounting a plurality of image forming units on the image forming unit mounting portion to form a color image.

Images