JP2015004791A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that is formed of a frame structure that has reduced size and weight, can be manufactured at low cost, and has excellent rigidity.SOLUTION: An image forming apparatus includes an image forming unit for forming toner images on sheets, an image reading unit that is arranged above the image forming unit to read images of documents, a first rectangular pipe that supports one end of the image reading unit and is a cantilever support beam, a second rectangular pipe that supports the other end of the image reading unit and is a cantilever support beam, and a third rectangular pipe that is joined to the respective ends, which are free ends, of the beams of the first rectangular pipe and the second rectangular pipe and supports the image reading unit at the middle of the beams. The first to third rectangular pipes are arranged respectively so that seams are formed on a lateral face on which a force is applied in a direction to receive compressive deformation due to the self-weight of the image reading unit.

Description

  The present invention relates to an image forming apparatus such as a multifunction machine, a copier, a printer, and a facsimile machine, which is configured by mounting an electrophotographic image forming unit on a frame structure.

  Conventionally, a configuration in which a rectangular metal plate material is formed into a rectangular pipe having a seam by bending and used for a frame structure of an image forming apparatus is disclosed (Patent Document 1). According to this configuration, it is possible to provide a highly rigid frame structure using a rectangular pipe and an image forming apparatus having the same while being small and light and low cost.

JP2007-118087

  However, the rectangular pipe of the conventional example has low rigidity against an external force in a direction orthogonal to the joint. For this reason, the rigidity may be insufficient depending on the arrangement direction of the rectangular pipes in the frame structure. In order to avoid this, if the material plate thickness or the outer shape of the rectangular pipe is increased, the image forming apparatus may be increased in size, weight, and cost.

  An object of the present invention is to provide an image forming apparatus constituted by a frame structure having excellent rigidity while maintaining small size, light weight, and low cost.

A typical configuration of the present invention for achieving the above object is as follows.
An image forming unit for forming a toner image on the sheet;
An image reading unit disposed above the image forming unit for reading an image of a document;
A first rectangular pipe that supports one end of the image reading unit and serves as a cantilever support beam;
A second rectangular pipe that supports the other end of the image reading unit and serves as a cantilever support beam;
A third rectangular pipe that is joined to each of the ends of the first rectangular pipe and the second rectangular pipe that are free ends of the beam and supports the image reading unit on the middle of the beam; Prepared,
The first to third rectangular pipes are respectively arranged so that the seam is placed on a side surface to which a force is applied in a direction of being subjected to compressive deformation due to the weight of the image reading unit.

  With the above configuration, it is possible to provide an image forming apparatus configured by a frame structure having excellent rigidity while maintaining small size, light weight, and low cost.

1 is a perspective view showing a frame structure of an image forming apparatus. FIG. 6 is a top view showing a positional relationship between a support member on the lower surface of the external housing and the center of gravity of the image forming apparatus. FIG. 6 is a top view showing a positional relationship between a support member on the upper surface of the upper housing and the center of gravity of the image reading unit and the document conveying unit. The top view which shows the positional relationship of the supporting member of the mounting surface of an internal housing | casing, and the gravity center of an internal unit. The fragmentary sectional view which shows the fixing method of a connection member. The perspective view which shows an example of the rectangular pipe which comprises a frame structure. The figure which shows the result of the maximum displacement amount of a rectangular pipe, and explanatory drawing of calculation conditions. The fragmentary perspective view which shows the joint direction of the rectangular pipe in an upper housing | casing. The fragmentary perspective view which shows the joint direction of the rectangular pipe in the mounting surface with respect to the external housing | casing of an internal housing | casing. 1 is a schematic sectional view of an image forming apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in the following embodiments should be changed as appropriate according to the configuration of the apparatus to which the present invention is applied and various conditions. Therefore, the scope of the present invention is not intended to be limited to them.

(Image forming device)
FIG. 10 is a schematic sectional view of the image forming apparatus. FIG. 10 illustrates a digital color multifunction peripheral that is an example of the image forming apparatus 1 of the present embodiment. The image forming apparatus 1 includes an image forming unit 100, an image reading unit 200 disposed above the image forming unit 100, and a document conveying unit 300 placed on the image reading unit 200.

(Original transport section)
In the document transport unit 300, the document D set upward on the document tray 301 is fed one by one in order from the first page. The document D passes over the platen glass 201 of the image reading unit 200 through a curved path. At this time, the image reading unit 200 reads an image of the document D. The original D on which the image has been read is discharged to a discharge tray 302.

  Further, the document conveying unit 300 is supported so as to be openable and closable with respect to the image reading unit 200 by a rotating hinge (not shown). In addition, a free stop mechanism (not shown) provided in the rotary hinge is independently held in an open state within a range of a predetermined opening angle.

(Image reading unit)
The image reading unit 200 performs image reading processing by the scanner unit 202 held at a predetermined position when the document D conveyed by the document conveying unit 300 passes from the left to the right in FIG. 10 on the platen glass 201. Do.

  Specifically, the reading surface of the document D is irradiated with light from the lamp 203 of the scanner unit 202, and reflected light from the document D is guided to the lens 207 via the mirror 204, the mirror 205, and the mirror 206. Then, the light passing through the lens 207 is imaged on the imaging surface of the image sensor 208.

  The image reading unit 200 also performs image reading processing by lifting the document conveying unit 300 without using it, setting the document D directly on the platen glass 201, and scanning the scanner unit 202 from left to right. It is possible. That is, the image reading unit 200 does not necessarily have to be equipped with the document conveying unit 300 and may be provided with a document pressing member that presses the document D set on the platen glass 201.

(Image forming part)
The image forming unit 100 includes a process cartridge 101 that forms toner images of Y (yellow), M (magenta), C (cyan), and K (black). Each color process cartridge 101 (101Y, 101M, 101C, 101K) has the following process means. In the image forming unit 100, since the four 101 have the same configuration, the suffixes Y, M, C, and K are omitted as appropriate.

  The surface of the photosensitive drum 102 is uniformly charged by the charging roller 103, and then a latent image is formed by the laser scanner 104 driven based on the transmitted image information signal. The latent image is developed as a toner image by the developing device 105. The toner consumed by development is appropriately replenished from each toner bottle 106 (106Y, 106M, 106C, 106K) to each developing device 105 via a replenishment path (not shown).

  The toner image on the photosensitive drum 102 is sequentially transferred onto the intermediate transfer belt 108 with a predetermined pressure and an electrostatic load bias applied by the primary transfer roller 107. After transfer, a slight residual toner remaining on the photosensitive drum 102 is removed by the photosensitive drum cleaner 109 to prepare for the next image formation. The removed residual toner is accommodated in the collection container 110 via a conveyance path (not shown).

  On the other hand, the sheet P fed one by one from the feeding cassette 111 is subjected to skew correction by forming a loop by following the tip of the nip portion of the registration roller pair 112. Thereafter, the registration roller pair 112 conveys the sheet P to the secondary transfer unit in synchronization with the toner image on the intermediate transfer belt 108. The toner image on the intermediate transfer belt 108 is transferred to the sheet P by applying a predetermined pressure and electrostatic load bias at the secondary transfer nip including the secondary transfer inner roller 113 and the secondary transfer outer roller 114. Is done.

  After the transfer, a slight residual toner remaining on the intermediate transfer belt 108 is removed by the transfer cleaner 115 to prepare for the next image formation. The removed residual toner is accommodated in the collection container 110 via a conveyance path (not shown). The transferred toner image on the sheet P is fixed by being heated and pressed by the fixing device 116. Thereafter, the sheet P is discharged and stacked by a discharge roller pair 117 on a discharge tray 118 (discharge unit) disposed inside the cylinder between the image reading unit 200 and the image forming unit 100.

(Frame structure structure)
Next, the configuration of the frame structure that supports each part of the above-described image forming apparatus will be described. FIG. 1 is a perspective view showing a frame structure of the image forming apparatus. As shown in FIG. 1, the frame structure 2 is composed of three members (an outer casing 2a, an upper casing 2b, and an inner casing 2c).

  The external housing 2 a is configured to be slightly smaller than the outer shape of the image forming unit 100 and fixedly supports the entire image forming unit 100. The upper housing 2b supports the image reading unit 200 and the document conveying unit 300. The internal housing 2c supports the process cartridge 101, the laser scanner 104, the intermediate transfer belt 108, and the fixing device 116 inside the external housing 2a.

  The outer casing 2a is configured by bringing the upper device to one side (right side surface), so that the discharge sheet outlet 400 is widely opened on at least three side surfaces of the device side surface. For this reason, it is possible to perform the operation of taking out the discharged sheet P from any of the front, left side, and back side of the image forming apparatus 1.

  As shown in FIG. 1, three support members 3 for supporting the image forming apparatus 1 are disposed on the lower surface of the external housing 2a.

  FIG. 2 is a top view showing the positional relationship between the support member on the lower surface of the external housing and the center of gravity of the image forming apparatus. The three support members 3 indicate a positional relationship with the center of gravity G1 of the image forming apparatus 1.

  The center of gravity G1 of the image forming apparatus 1 moves within a predetermined area due to a change in the amount of toner contained in the toner bottle 106 and the collection container 110, a change in the amount of sheet P contained in the feeding cassette 111 and the discharge tray 118, and the like. Thus, even when the center of gravity G1 of the image forming apparatus 1 moves, the positions of the three support members 3 are determined so as to be within the range of the region S1 determined by the three support members 3.

  With the above configuration, the mounting plane of the image forming apparatus 1 is uniquely determined. For this reason, even if it is a case where it installs on the floor surface with distortion, the external housing | casing 2a does not deform | transform excessively. Therefore, the image forming apparatus 1 can perform stable image formation.

  The image reading unit 200 is placed on the upper surface of the upper housing 2b. For this reason, as shown in FIG. 1, the three support members 4 for placing the image reading unit 200 are disposed.

  FIG. 3 is a top view showing the positional relationship between the support member on the upper surface of the upper housing and the center of gravity of the image reading unit and the document conveying unit.

  The center of gravity G2 of the image reading unit 200 and the document conveying unit 300 moves within a predetermined area by scanning of the scanner unit 202, opening / closing of the document conveying unit 300, the weight of the document, and the like. For this reason, the positions of the three support members 4 are arranged as follows. That is, even when the center of gravity G2 of the image reading unit 200 and the document conveying unit 300 moves, the image reading unit 200 and the document conveying unit 300 are arranged so as to be within the range of the region S2 determined by the three support members 4.

  With the above configuration, the placement plane of the image reading unit 200 is uniquely determined. For this reason, even when the upper surface of the upper housing 2b is distorted due to component tolerance, user operation force, or the like, the image reading unit 200 is not excessively deformed. Therefore, the image reading unit 200 can perform stable image reading.

  As shown in FIG. 1, the outer casing 2a is provided with three support members 5 for placing the inner casing 2c.

  FIG. 4 is a top view showing the positional relationship between the support member on the mounting surface of the internal housing and the center of gravity of the internal unit.

  The three support members 5 are arranged so that the center of gravity G3 of the internal unit falls within the range S3 determined by the three support members 5. With the above configuration, the mounting plane of the internal housing 2c (see FIG. 1) is uniquely determined. Therefore, even when the external housing 2a is distorted due to component tolerance, user operation force, or the like, the internal housing The body 2c and the internal unit supported by the internal housing 2c are not deformed excessively. Therefore, the image reading unit 200 can perform stable image formation.

  Each of the support member 3, the support member 4, and the support member 5 of the present embodiment is made of an elastic body such as rubber. Thereby, vibration transmission between the image forming apparatus 1 and the floor surface, between the image forming unit 100 and the image reading unit 200, and between the external housing 2a and the internal housing 2c can be prevented. Image reading and image formation can be performed.

  However, when there is no risk of image failure due to vibration transmission, it is not necessary to limit each support member to an elastic body. For example, each support member may be configured to be supported by a rigid body.

  Further, the number of support points of each support member 3, support member 4, and support member 5 of the present embodiment is not limited to three as long as the installation plane is uniquely determined.

  The upper housing 2b shown in FIG. 1 has a connecting member 6, and connects the image reading unit 200 (see FIG. 10) placed on the upper housing 2b to the upper housing 2b. Further, the external housing 2a has a connecting member 7, and connects the internal housing 2c placed on the upper housing 2b to the upper housing 2b.

  FIG. 5 is a partial cross-sectional view showing a method of fixing the connecting member. The connecting member 6 is fixed to the upper housing 2b by screws 8 in the vicinity of the support member 4. Further, the connecting member 7 is fixed to the external housing 2 a with screws 8 in the vicinity of the support member 5.

  On the other hand, the housing 9 and the internal housing 2c (see FIG. 1) of the image reading unit 200 are fixed by the step screw 11 via the elastic bush 10.

  As shown in FIG. 5, the elastic bush 10 is formed with a groove 10a. By engaging the hole 6a of the connecting member 6 and the hole 7a of the connecting member 7 with the groove 10a, the image reading unit 200, The upward movement of the internal housing 2c is restricted.

  Thus, by using the elastic bush 10 made of an elastic body in the connecting portion, it is possible to prevent the three-point support described above from being hindered and to prevent vibration transmission.

  In the case where the three-point support configuration is not hindered and there is no possibility of image failure due to vibration transmission, the configuration is not necessarily limited to the elastic body. That is, in that case, it may be configured to be connected by a rigid body.

  Further, in the present embodiment, the configuration using the three connection members 6 and the connection members 7 in the vicinity of the support members 4 and the support members 5 has been described, but the configuration is not limited thereto. That is, as long as the upward movement of the image reading unit 200 and the internal housing 2c is restricted, the arrangement and the number are not limited to this.

(Pipe rigidity)
FIG. 6 is a perspective view showing an example of a rectangular pipe constituting the frame structure. The frame structure 2 of this embodiment forms a rectangular pipe 12 having seams 12a by pressing or bending a rectangular metal plate material made of, for example, an electrogalvanized steel sheet. Then, a plurality of molded rectangular pipes are combined and joined by welding or the like. Thereby, the frame structure 2 is configured. When the joints 12a of the rectangular pipe 12 are joined at a plurality of locations by the welded portion 12b, the joints are preferably prevented from opening.

  FIG. 7 is a chart showing the results of the maximum displacement amount of the rectangular pipe and explanatory diagrams of calculation conditions. The chart shown in FIG. 7A shows the calculation result of the maximum displacement amount of the rectangular pipe 12 under the conditions shown in FIGS. 7B to 7D. What is different under the conditions shown in FIGS. 7B to 7D is the placement direction of the joint 12a of the rectangular pipe 12. FIG.

  In any of the conditions of FIGS. 7B to 7D, the bottom surface 12f of 5 mm was supported by the support member from both ends of the rectangular pipe 12, and the center was pressed with a load of 300N. A rectangular pipe 12 having a plate thickness of 0.8 mm, a pipe outer shape of 20 mm × 20 mm, and a total length of 600 mm was used.

  The rigidity is highest when the side surface 12c having the joint 12a shown in FIG. 7B is pressed. As shown in FIG. 7A, the maximum displacement is the smallest at 1.707 mm.

  Next, the rigidity is high when the opposing side surface 12d of the joint 12a shown in FIG. 7C is pressed, and the maximum displacement is 1.717 mm as shown in FIG. 7A.

  The lowest rigidity is when the side surface 12e of the joint 12a shown in FIG. 7D is pressed, and the maximum displacement is the largest at 1.876 mm as shown in FIG. 7A.

  From the above calculation results, when deformation occurs due to an external force acting on the rectangular pipe 12, if the rectangular pipe 12 is disposed so that the side surface 12c having the joint 12a is subjected to compressive deformation, the frame structure 2 is most It can be configured with high rigidity.

(Seam arrangement of rectangular pipes on the mounting surface of the image reading unit)
FIG. 8 is a partial perspective view showing the joint direction of the rectangular pipe in the upper housing. FIG. 8A is a view seen from the upper side, and FIG. 8B is a view seen from the lower side.

  In the frame structure 2 of the image forming apparatus 1 of the present embodiment, the upper portion of the external housing 2a is brought close to the right side surface so that the discharged sheet P can be taken out from three directions. For this reason, the front side pipe 13 (first rectangular pipe) and the rear side pipe 14 (second rectangular pipe) each have a cantilever part 13b and a cantilever part 14b serving as cantilever support beams. .

  The front pipe 13 supports one end side of the image reading unit 200, and the rear pipe 14 supports the other end side of the image reading unit 200. The left pipe 15 (third rectangular pipe) joined to the end 13c and the end 14c, which are free ends of the cantilever of the front pipe 13 and the rear pipe 14, has a middle part of the beam. The support member 4 that supports the weight of the image reading unit 200 is disposed.

  From the above configuration, when the weight of the image reading unit 200 is received, the cantilever portion 13b of the front pipe 13 and the cantilever portion 14b of the rear pipe 14 are displaced downward as shown by the broken lines in FIG. . Further, the central portion of the left pipe 15 is displaced downward. That is, the front side pipe 13 and the rear side pipe 14 are displaced in a direction in which the lower side surface receives compression.

  Here, if the joint 13a of the front pipe 13 and the joint 14a of the rear pipe 14 are disposed downward, the rigidity of the front pipe 13 and the rear pipe 14 becomes the highest. Thereby, the amount of displacement of the front pipe 13 and the rear pipe 14 due to the weight of the image reading unit 200 can be minimized.

  Further, the left pipe 15 is displaced in a direction in which the upper side receives compression. Here, when the joint 15a of the left pipe 15 is disposed upward, the left pipe 15 has the highest rigidity, and the displacement of the left pipe 15 can be minimized.

  As shown in FIG. 8, the weight of the image reading unit 200 is received by the two support members 4 on the right side of the upper housing 2b, and the right front column 17 and the right rear column 18 of the external housing 2a below it. Supported by. For this reason, it does not act in the direction in which the rectangular pipes (the front pipe 13, the rear pipe 14, the left pipe 15, and the right pipe 16) constituting the upper housing 2b are bent.

  The open / close door 19 is locked to the right pipe 16 (fourth rectangular pipe) of the upper housing 2b. The open / close door 19 is disposed along one side surface of the image forming unit 100 and is a door for performing jam processing in the conveyance path of the sheet P.

  As shown by the broken line in FIG. 8A, when the locking force of the open / close door 19 is received, the central portion of the right pipe 16 is displaced in the right direction. That is, the right side pipe 16 is displaced in the direction in which the left side is subjected to compression. In this case, when the seam 16a of the right pipe 16 is disposed to the left as shown in FIG. 8A (the side surface opposite to the side surface with the open / close door 19), the rigidity against the external force becomes the highest. Then, the amount of displacement of the right pipe 16 can be minimized.

  With the above configuration, it is possible to minimize the amount of displacement of the mounting surface of the image reading unit 200, so that a stable image can be obtained in the image forming apparatus 1.

(Seam arrangement of rectangular pipes on the mounting surface of the internal housing)
FIG. 9 is a partial perspective view showing the joint direction of the rectangular pipe on the mounting surface of the inner casing with respect to the outer casing. FIG. 9A is a view of the external housing 2a as viewed from above, and FIG. 9B is a view of the internal housing 2c as viewed from below.

  As shown in FIG. 9A, the front pipe 20 and the rear pipe 21 of the external housing 2a on the mounting surface are fixedly supported by the right front column 17 and the right rear column 18 at the right end 20b and the right end 21b, respectively. . On the other hand, the left end 20c and the left end 21c are fixedly supported by the left front column 26 and the left rear column 27, respectively.

  The front pipe 20 and the rear pipe 21 receive the weight of the internal housing 2c with both ends fixedly supported.

  At this time, the front pipe 20 and the rear pipe 21 are displaced in the direction in which the upper surface is compressed (the direction of the broken line). For this reason, when the seams 20a and 21a are arranged so that the seams 21a face upward, the rigidity becomes the highest and the displacement of the front pipe 20 and the rear pipe 21 can be minimized.

  Further, the internal weight of the internal housing 2c is applied to the support member 5 disposed in the middle of the left pipe 22 of the external housing 2a. Thereby, as shown by the broken line in FIG. 9A, the center of the left pipe 22 is displaced downward.

  At this time, the left pipe 22 is fixedly supported by the front pipe 20 at the front end 22b and the rear pipe 22 at the rear end 22c. For this reason, in the state where both ends are fixedly supported, the support member 5 disposed in the middle of the beam receives the weight of the internal housing 2c, and the center is displaced downward. That is, the left pipe 22 is displaced in the direction in which the upper side surface is compressed. For this reason, when the joint line 22a of the left pipe 22 is disposed upward, the left pipe 22 has the highest rigidity and the amount of displacement can be minimized.

  As shown in FIG. 9B, the right end 23b of the front pipe 23 and the right end 24b of the rear pipe 24 of the inner housing 2c on the mounting surface are supported by the support member 5, respectively. On the other hand, the left end 23c of the front pipe 23 and the left end 24c of the rear pipe 24 are in a state of floating from the placement surface and become free ends. The front pipe 23 and the rear pipe 24 of the internal housing 2c are in a cantilevered state in this way.

  As described above, the internal housing 2c supports an image forming unit related to toner image formation, such as the process cartridge 101, the laser scanner 104, the intermediate transfer belt 108, and the fixing device 116. For this reason, the weight of the image forming unit is given to the entire area of the beam of the internal housing 2c. Then, the left end 23c of the front side pipe 23 and the left end 24c of the rear side pipe 24 are displaced downward as shown by a broken line in FIG.

  That is, the front pipe 23 and the rear pipe 24 are displaced in the direction in which the lower surface is compressed. For this reason, when the joint 23a of the front pipe 23 and the rear pipe 24a are disposed downward, the rigidity of the front pipe 23 and the rear pipe 24 becomes the highest. By doing so, the amount of displacement can be minimized.

  The left pipe 25 of the inner casing 2c is given its own weight to the entire area of the beam in a state where its middle is supported by the support member 5 of the outer casing 2a. For this reason, as shown by the broken line in FIG. 9B, the front end 25b and the front end 25c of the left pipe 25 are displaced downward. That is, the left pipe 25 is displaced in the direction in which the lower surface is compressed.

  Therefore, by disposing the joint 25a of the left pipe 25 downward, the left pipe 25 has the highest rigidity and the amount of displacement can be minimized.

  With the above configuration, it is possible to minimize the amount of displacement of the mounting surface of the image forming unit. Therefore, it is possible to reduce fluctuations in the relative position and inclination of the image forming units. A stable image can be obtained.

D ... Original P ... Sheet 1 ... Image forming apparatus 2 ... Frame structure 2a ... External housing 2b ... Upper housing 2c ... Internal housing 12 ... Rectangular pipe 12a ... Joint 13 ... Front pipe 13a ... Joint 14 ... Rear pipe 14a ... Joint 15 ... Left pipe 16 ... Right pipe 19 ... Open / close door 20 ... Front pipe 20a ... Joint 21 ... Rear pipe 21a ... Joint 22 ... Left pipe 23 ... Front pipe 24 ... Rear pipe 25 ... Left pipe 100 ... Image forming unit 200 ... Image reading unit

Claims (5)

An image forming unit for forming a toner image on the sheet;
An image reading unit disposed above the image forming unit for reading an image of a document;
A first rectangular pipe that supports one end of the image reading unit and serves as a cantilever support beam;
A second rectangular pipe that supports the other end of the image reading unit and serves as a cantilever support beam;
A third rectangular pipe that is joined to each of the ends of the first rectangular pipe and the second rectangular pipe that are free ends of the beam and supports the image reading unit on the middle of the beam; Prepared,
The image forming apparatus, wherein the first to third rectangular pipes are arranged so that the seam is placed on a side surface to which a force in a direction of compressive deformation is applied by the weight of the image reading unit. . An image forming unit for forming a toner image on the sheet;
An image reading unit disposed above the image forming unit for reading an image of a document;
A first rectangular pipe that supports one end of the image reading unit and serves as a cantilever support beam;
A second rectangular pipe that supports the other end of the image reading unit and serves as a cantilever support beam;
A third rectangular pipe that is joined to each of the ends of the first rectangular pipe and the second rectangular pipe that are free ends of the beam and supports the image reading unit on the middle of the beam; Prepared,
The seam of the first rectangular pipe and the seam of the second rectangular pipe are disposed downward;
An image forming apparatus, wherein a seam of the third rectangular pipe is disposed upward. A discharge unit disposed between the image forming unit and the image reading unit and configured to discharge a sheet on which an image is formed by the image forming unit;
3. The image forming apparatus according to claim 1, wherein at least three side surfaces of the discharge sheet take-out port for taking out the sheets stacked on the discharge unit are opened. . There is an open / close door for jamming the sheet on one side of the image forming apparatus,
A fourth rectangular pipe disposed on the opposite side of the third rectangular pipe on the mounting surface of the image reading unit and locking the open / close door;
The said 4th rectangular pipe is formed so that the said joint may come to the side surface to which the force of the direction which receives a compressive deformation is applied, The Claim 1 thru | or 3 characterized by the above-mentioned. Image forming apparatus.   The image forming apparatus according to claim 4, wherein a seam of the fourth rectangular pipe is disposed toward a side surface opposite to the side surface of the opening / closing door.

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