JP7337606B2 - Frame of image forming apparatus - Google Patents

Description

The present invention relates to a frame for image forming apparatuses such as electrophotographic copiers and electrophotographic printers (for example, laser beam printers, LED printers, etc.).

A frame of an image forming apparatus is generally formed by joining a plurality of sheet metals such as a front plate, a rear plate, and a stay connecting the front plate and the rear plate by welding or the like. By joining such sheet metals in a state where they are assembled with high positional accuracy, the positional accuracy between the members supported by the frame is maintained, making it possible to form a high-quality image.

On the other hand, Japanese Patent Application Laid-Open No. 2002-200002 describes a configuration for assembling a first metal sheet and a second metal sheet, which are sheet metals constituting a frame of an image forming apparatus, with high positional accuracy. The configuration described in Patent Document 1 is a configuration in which the projection formed on the first metal plate is inserted into the opening formed on the second metal plate to assemble the two. Inside the opening of the second sheet metal, a first bulging portion abutting one side in the plate thickness direction of the projecting portion of the first sheet metal and a second bulging portion abutting the other side are formed. there is By sandwiching the projecting portion in the plate thickness direction by these first and second bulging portions, the position of the first sheet metal relative to the second sheet metal in the plate thickness direction is determined. In addition, by making the width of the opening and the width of the protruding portion substantially the same in the direction perpendicular to the insertion direction of the first sheet metal into the second sheet metal and the thickness direction of the first sheet metal, the first sheet metal is inserted into the second sheet metal. Determine the position in the orthogonal direction.

JP 2008-116619 A

However, in the configuration described in Patent Literature 1, there is no portion for restricting the movement of the first sheet metal in the direction opposite to the direction of insertion of the first sheet metal into the second sheet metal. Therefore, if an unintended force is applied to the first metal sheet or the second metal sheet while the first metal sheet is attached to the second metal sheet, the first metal sheet moves in the direction opposite to the insertion direction of the second metal sheet. , the first metal sheet and the second metal sheet may be separated from each other, degrading the positional accuracy.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a frame for an image forming apparatus that can prevent deterioration in positional accuracy due to separation of sheet metals constituting the frame.

A typical configuration of the frame of the image forming apparatus according to the present invention for achieving the above object is a first frame made of sheet metal and formed with a first through hole and a second through hole penetrating in the plate thickness direction. a first support having a portion; and a second support made of sheet metal and assembled to the first support, the second support being bent up from a second portion extending parallel to the first portion, the first through-hole and a second support having an insertion portion inserted into the hole, wherein the insertion portion is inserted into the first through hole and is inserted into the first through hole from a direction opposite to the insertion direction. Having an engaging portion that is inserted into and engaged with the second through hole, the insert portion is inserted into the first through hole, and in a state where the engaging portion is engaged with the second through hole, The first portion is sandwiched between the second portion and the insertion portion in the plate thickness direction of the first support , and the second through hole is formed above the first through hole in the vertical direction. characterized in that

According to the present invention, it is possible to suppress deterioration in positional accuracy due to separation of the sheet metals forming the frame of the image forming apparatus.

1 is a schematic perspective view of an image forming apparatus; FIG. 1 is a schematic cross-sectional view of an image forming apparatus; FIG. 2 is a perspective view of a frame of the image forming apparatus; FIG. 2 is a perspective view of a frame of the image forming apparatus; FIG. It is a perspective view when a rear bottom plate is assembled. FIG. 10 is a perspective view when the rear side plate is assembled; FIG. 10 is a perspective view when the rear side plate is assembled; 4 is a perspective view of a support portion of the rear side plate; FIG. It is a perspective view of the bending part of a rear side board. FIG. 4 is a perspective view when the middle stay is assembled; FIG. 4 is a perspective view when the front side plate is assembled; It is a perspective view at the time of assembling|attaching a left support|pillar. FIG. 4 is a perspective view when the front lower stay is assembled; FIG. 11 is a perspective view when the right strut is assembled; Fig. 10 is a perspective view when the lower left stay is assembled; FIG. 11 is a perspective view when the upper left stay is assembled; It is a top view of the through-hole of an upper left stay, and the insertion part of a left support|pillar. It is a figure which shows a mode that an upper left stay is assembled|attached with respect to a left support|pillar. It is a figure which shows the other structure of an upper left stay and a left support|pillar. FIG. 11 is a perspective view when the lower right stay is assembled; It is a perspective view of a lower right stay, a rear side plate, and a right support|pillar. FIG. 4 is an enlarged perspective view of an engagement portion between a lower right stay and a rear side plate; FIG. 4 is an enlarged perspective view of an engagement portion between a lower right stay and a right post; FIG. 10 is a perspective view when the rear side plate is assembled; FIG. 10 is a perspective view when the right middle stay is assembled; FIG. 11 is a perspective view when the right strut is assembled; FIG. 4 is an enlarged perspective view of an engaging portion between the right strut and the right strut; FIG. 11 is a perspective view when the upper right stay is assembled; FIG. 4 is a perspective view of a jig used for joining frames; It is a perspective view of a frame and a jig. It is a perspective view of a frame and a jig.

(First embodiment)
<Image forming apparatus>
Hereinafter, first, the overall configuration of the image forming apparatus according to the first embodiment of the present invention will be described together with the operation during image formation with reference to the drawings. It should be noted that the dimensions, materials, shapes, relative positions, etc. of the components described below are not intended to limit the scope of the present invention only to them, unless otherwise specified.

The image forming apparatus A according to this embodiment is an intermediate tandem system that forms an image by transferring four color toners of yellow Y, magenta M, cyan C, and black K onto an intermediate transfer belt and then transferring the image onto a sheet. image forming apparatus. In the following description, although the subscripts Y, M, C, and K are attached to the members using the toners of the respective colors, the configurations and operations of the members are different except that the colors of the toners used are different. Since they are substantially the same, suffixes are omitted as appropriate unless they need to be distinguished.

FIG. 1 is a schematic perspective view of an image forming apparatus A. FIG. FIG. 2 is a schematic cross-sectional view of the image forming apparatus A. As shown in FIG. As shown in FIGS. 1 and 2, the image forming apparatus A includes an image forming section 44 that forms a toner image and transfers it onto a sheet, a sheet feeding section 43 that feeds the sheet toward the image forming section 44, A fixing unit 45 for fixing the toner image on the sheet is provided. An image reading unit 41 for reading an image of a document is provided on the upper portion of the image forming apparatus A. As shown in FIG.

The image forming section 44 includes process cartridges 3 (3Y, 3M, 3C, 3K), a laser scanner unit 15, and an intermediate transfer unit 49. FIG. The process cartridge 3 is detachably attached to an apparatus main body 30 of the image forming apparatus A, and includes a photosensitive drum 6 (6Y, 6M, 6C, 6K), a charging roller 8 (8Y, 8M, 8C, 8K), and a developing device. 4 (4Y, 4M, 4C, 4K).

The intermediate transfer unit 49 includes primary transfer rollers 5 (5Y, 5M, 5C, 5K), an intermediate transfer belt 14, a secondary transfer roller 28, a secondary transfer opposing roller 23, a drive roller 21, and a tension roller 22. The intermediate transfer belt 14 is stretched around a secondary transfer opposing roller 23, a driving roller 21, and a tension roller 22. The driving roller 21 is rotated by the driving force of a motor (not shown), and is driven by the rotation to move around. do.

Next, an image forming operation by the image forming apparatus A will be described. First, when an image forming job signal is input to a control unit (not shown), the sheets S stacked and accommodated in the sheet cassette 42 are fed to the registration rollers 9 by the feed rollers 16 . Next, the sheet S is sent to a secondary transfer portion formed by the secondary transfer roller 28 and the secondary transfer opposing roller 23 at a predetermined timing by the registration rollers 9 .

On the other hand, in the image forming section, first, the surface of the photosensitive drum 6Y is charged by the charging roller 8Y. After that, the laser scanner unit 15 irradiates the surface of the photosensitive drum 6Y with laser light according to an image signal transmitted from an external device (not shown) or the like to form an electrostatic latent image on the surface of the photosensitive drum 6Y.

After that, the developing device 4Y attaches yellow toner to the electrostatic latent image formed on the surface of the photosensitive drum 6Y to form a yellow toner image on the surface of the photosensitive drum 6Y. The toner image formed on the surface of the photosensitive drum 6Y is primarily transferred to the intermediate transfer belt 14 by applying a bias to the primary transfer roller 5Y.

By a similar process, magenta, cyan, and black toner images are also formed on the photosensitive drums 6M, 6C, and 6K. By applying a primary transfer bias to the primary transfer rollers 5M, 5C, and 5K, these toner images are superimposedly transferred onto the yellow toner image on the intermediate transfer belt . As a result, a full-color toner image is formed on the intermediate transfer belt 14 surface.

Note that the toner inside the developing device 4 is used by the above-described developing process, and when the amount of toner inside the developing device 4 decreases, the toner bottle 32 (32Y, 32M, 32C, 32K) supplies toner to each developing device 4. Toner of each color is replenished. The toner bottle 32 is configured to be attachable to and detachable from the apparatus main body 30 of the image forming apparatus A. As shown in FIG.

After that, the intermediate transfer belt 14 rotates to send the full-color toner image to the secondary transfer portion. Then, the full-color toner image on the intermediate transfer belt 14 is transferred to the sheet S by applying a bias to the secondary transfer roller 28 in the secondary transfer portion.

Next, the sheet S onto which the toner image has been transferred is subjected to heat and pressure processing in the fixing section 45, whereby the toner image on the sheet S is fixed to the sheet S. FIG. After that, the sheet S on which the toner image is fixed is discharged to the discharge section 19 by the discharge roller 18 .

<Frame of Image Forming Apparatus>
Next, the frame 31 of the image forming apparatus A will be described.

FIG. 3 is a perspective view of the frame 31 of the image forming apparatus A viewed from the front side of the apparatus main body 30. As shown in FIG. FIG. 4 is a perspective view of the frame 31 of the image forming apparatus A as seen from the back side of the apparatus main body 30. As shown in FIG. Note that the arrow X direction shown in the drawing is the horizontal direction, which indicates the horizontal direction of the image forming apparatus A. As shown in FIG. The arrow Y direction is the horizontal direction and indicates the front-rear direction of the image forming apparatus A. As shown in FIG. The direction of the arrow Z is the vertical direction and indicates the vertical direction of the image forming apparatus A. As shown in FIG. The front side of the image forming apparatus A is the side on which the user normally stands to operate an operation unit (not shown) for making settings related to image formation. . The left side of the image forming apparatus A is the left side as seen from the front side, and the right side is the right side as seen from the front side.

As shown in FIGS. 3 and 4, the image forming apparatus A includes a front side plate 55, a left strut 56, and a right strut 67 made of sheet metal as a frame 31 on the front side. The left strut 56 is connected to one end side of the front side plate 55 . The right strut 67 is connected to the other side of the front side plate 55 and vertically divided into two as right struts 58 and 63 . The left strut 56 and right strut 58 are connected by a front lower stay 57 .

The image forming apparatus A also includes a rear plate 50 made of sheet metal as a frame 31 on the rear side. The rear plate 50 is arranged to face the front plate 55 and supports the process cartridge 3 together with the front plate 55 . The rear plate 50 is vertically divided into three rear plates 52, 53, and 62, each of which has a plate thickness of about 0.6 mm to 2 mm. A rear bottom plate 51 is provided below the rear side plate 52 .

Further, the image forming apparatus A includes a lower left stay 59, an upper left stay 60, a lower right stay 61, a middle right stay 65, and an upper right stay 64 as the frame 31 connecting the frame 31 on the front side and the frame 31 on the back side. , and a middle stay 54 . The left lower stay 59 connects the left strut 56 and the rear side plate 52 . The upper left stay 60 connects the left strut 56 and the rear side plate 53 . The lower right stay 61 connects the right strut 58 and the rear side plate 52 . The right middle stay 65 connects the rear side plate 53 and the right strut 58 . The upper right stay 64 connects the right strut 63 and the rear side plate 62 . The middle stay 54 connects the front side plate 55 and the rear side plate 53 .

In addition, each member which comprises the frame 31 mentioned above is each formed from the sheet metal of 1 sheet. These sheet metals are worked into a predetermined shape by drawing or the like, and then become the frame 31 through an assembly process and a joining process, which will be described later.

<Mounting process of frame>
Next, a process of assembling a plurality of sheet metals forming the frame 31 will be described. 5 to 28 are diagrams showing how the sheet metals forming the frame 31 are assembled.

As shown in FIG. 5, a stand 33 is used when the sheet metals forming the frame 31 are assembled. The stand 33 is provided with positioning pins 33a and 33b and a support 33c. First, the rear bottom plate 51 is placed on the stand 33 . The rear bottom plate 51 includes a flat portion 51w1 facing the mounting table 33 and a bent portion 51w2 bent from the flat portion 51w1. The bent raised portion 51w2 is formed at least on the side that engages with the rear side plate 52 . When the rear bottom plate 51 is placed on the stand 33, the positioning pin 33a of the stand 33 is inserted into the positioning hole 51a formed in the plane portion 51w1 of the rear bottom plate 51, whereby the position of the rear bottom plate 51 with respect to the stand 33 is adjusted. be decided.

Next, as shown in FIG. 6, the rear side plate 52 is assembled. The rear plate 52 is bent so as to have three planes. The rear side plate 52 includes a flat portion 52a positioned on the back surface of the image forming apparatus A, a bent portion 52b that is bent from the flat portion 52a and extends rearward of the image forming apparatus A, and a bent portion 52b that faces the bent portion 52b. A bent portion 52w that is bent with respect to the flat portion 52a is provided. The rear side plate 52 is inserted into and assembled with the rear bottom plate 51 . A projecting portion 52n and a stepped portion 52m are provided in the lower portion of the flat portion 52a of the rear side plate 52 by drawing so as to protrude in the plate thickness direction. A stepped bent portion 52p is provided below the bent portion 52b of the rear side plate 52 . The stepped portion 52m has a portion that is bent in the plate thickness direction (arrow Y direction) of the flat portion 52a and a portion that is bent and extends from that portion in the insertion direction (arrow Z direction) into the rear bottom plate 51 . The stepped bent portion 52p has a portion bent in the plate thickness direction (arrow X direction) of the bent portion 52b and a portion bent and extending from the bent portion in the insertion direction into the rear bottom plate 51 . The tip of the stepped portion 52m forms an inclined portion 52m1 that is inclined away from the flat portion 52a of the rear plate 52 with respect to the direction in which the rear plate 52 is inserted into the rear bottom plate 51 . The front end of the stepped bent portion 52p is an inclined portion 52p1 that is inclined away from the bent portion 52b of the rear side plate 52 with respect to the insertion direction of the rear side plate 52 into the rear bottom plate 51 . A through-hole 51n is formed in the bent and raised portion 51w2 of the rear bottom plate 51 so as to penetrate in the plate thickness direction (arrow Y direction).

When the rear side plate 52 is assembled, the stepped portions 52m and 52p of the rear side plate 52 are inserted into and engaged with the bent and raised portions 51w2 of the rear bottom plate 51 . At this time, the inclined portions 52m1 and 52p1 of the rear side plate 52 are brought into contact with the bent and raised portions 51w2 of the rear bottom plate 51 to guide the movement of the rear side plate 52 in the arrow Z direction. As a result, the bent and raised portion 51w2 of the rear bottom plate 51 is sandwiched from the plate thickness direction by the stepped portions 52m and 52p and the flat portions 52a and 52b of the rear side plate 52, and the rear plate 52 is bent in the arrow X direction and the arrow Y direction with respect to the rear bottom plate 51. position is determined. Also, the protrusion 52n of the rear side plate 52 is engaged with the through hole 51n of the rear bottom plate 51 . As a result, the edge 52n1 of the protrusion 52n abuts against the inner wall of the through hole 51n, and movement of the rear side plate 52 in the direction opposite to the direction of insertion into the rear bottom plate 51 is restricted. Further, the rear plate 52 contacts the rear bottom plate 51 at a position where the lower end portion of the rear plate 52 and the surface of the table 33 on which the rear bottom plate 51 is placed contacts, or at the flat portion 52a of the stepped portions 52m and 52p. , 52b and the upper end of the bent and raised portion 51w2 of the rear bottom plate 51, the positions of the rear side plate 52 and the rear bottom plate 51 in the direction of the arrow Z are determined. and the rear side plate 52 are finally determined.

Next, as shown in FIG. 7, the rear side plate 53 is assembled. The rear side plate 53 supports the process cartridge 3 which greatly affects image quality during image formation. Therefore, it is particularly desirable that the rear side plate 53 is assembled with high positional accuracy. The assembly structure of the rear side plate 53 will be described in detail below.

As shown in FIG. 7, the rear side plate 53 is bent so as to have three planes. The rear side plate 53 is positioned on the rear side of the image forming apparatus A, and is bent at a substantially right angle (89 to 90 degrees) from a support portion 53a that supports the process cartridge 3, and an image is formed by bending the support portion 53a. A bent portion 53b extending to the rear of the device A is provided. The rear plate 53 also includes a bent portion 53w that is bent with respect to the support portion 53a so as to face the bent portion 53b.

The support portion 53a of the rear plate 53 is arranged adjacent to the flat portion 52a of the rear plate 52 in the vertical direction, and is inserted into and assembled with the flat portion 52a of the rear plate 52 . The bent portion 53b of the rear plate 53 is arranged adjacent to the bent portion 52b of the rear plate 52 in the vertical direction, and is inserted into and assembled with the bent portion 52b of the rear plate 52 . The bent portion 53w of the rear plate 53 is arranged adjacent to the bent portion 52w of the rear plate 52 in the vertical direction, and is inserted into and assembled with the bent portion 52w of the rear plate 52 .

First, the assembly structure of the flat portion 52a of the rear side plate 52 and the support portion 53a of the rear side plate 53 will be described. 8 is a perspective view of the flat portion 52a of the rear plate 52 and the support portion 53a of the rear plate 53. FIG. Here, FIG. 8(a) shows the state before the rear side plate 52 and the rear side plate 53 are assembled, and FIG. 8(b) shows the state where the rear side plate 52 and the rear side plate 53 are assembled.

As shown in FIG. 8, the support portion 53a of the rear plate 53 has two protrusions 103 that protrude in the plate thickness direction of the rear plate 53, and an insertion direction (arrow Z direction) of the rear plate 53 into the rear plate 52. Two protruding stepped portions 104 are provided. Further, two protruding portions 105 protruding in the inserting direction with respect to the rear side plate 52 are provided at the lower portions of the two stepped portions 104 .

The projecting portion 103 is formed by drawing, and the amount of projection from the surface of the supporting portion 53a is about 0.3 mm to 2 mm. The projecting portion 103 is arranged adjacent to the stepped portion 104 in a direction perpendicular to the plate thickness direction of the rear plate 53 and the insertion direction of the rear plate 53 into the rear plate 52 (the arrow X direction). The tip of the projecting portion 105 forms an inclined portion 105a that is inclined in the direction away from the support portion 53a with respect to the insertion direction of the rear side plate 53 into the rear side plate 52. As shown in FIG.

The stepped portion 104 has a portion that is bent in the plate thickness direction of the rear plate 53 and a portion that is bent and extends from the portion in the direction of insertion into the rear plate 52 . The tip of the stepped portion 104 forms an inclined portion 104a in a direction away from the support portion 53a that is inclined with respect to the insertion direction of the rear plate 53 into the rear plate 52. As shown in FIG.

A bent portion 52a1 bent in the direction of the arrow Y and a raised portion 52a2 bent in the direction of the arrow Z from the bent portion 52a1 are formed on the upper portion of the flat portion 52a of the rear side plate 52 . Two through-holes 107 are formed in the bent portion 52a2 so as to extend therethrough in the plate thickness direction (arrow Y direction). A through hole 108 penetrating in the plate thickness direction is formed at the boundary between the bent portion 52a1 and the bent and raised portion 52a2.

When the rear plate 53 is assembled to the rear plate 52, the inclined portion 104a of the stepped bent portion 104 of the rear plate 53 and the inclined portion 105a of the projecting portion 105 abut against the bent and raised portion 52a2 of the rear plate 52, thereby is guided to move in the direction of the arrow Z. Further, the stopper portion 106 of the rear plate 53 abuts against the abutment portion 109, which is the upper end portion of the bent portion 52a2 of the rear plate 52, thereby restricting the movement of the rear plate 53 in the inserting direction with respect to the rear plate 52.

When the rear plate 53 is assembled to the rear plate 52, the stepped portion 104 of the rear plate 53 is inserted into and engaged with the bent portion 52a2 of the rear plate 52. As shown in FIG. As a result, the bent portion 52a2 of the rear plate 52 is sandwiched from the plate thickness direction by the stepped portion 104 and the support portion 53a of the rear plate 53, and the position of the rear plate 53 in the arrow Y direction relative to the rear plate 52 is determined.

Also, the protrusion 103 of the rear plate 53 engages with the through hole 107 of the rear plate 52 . As a result, the edge 103a of the protrusion 103 abuts against the inner wall of the through hole 107, and movement of the rear plate 53 in the direction opposite to the insertion direction into the rear plate 52 is restricted.

Also, the projecting portion 105 of the rear side plate 53 engages with the through hole 108 of the rear side plate 52 . As a result, the protruding portion 105 abuts against the inner wall of the through hole 108, and the movement of the rear side plate 53 in the arrow X direction with respect to the rear side plate 52 is restricted.

In the vicinity of the stepped portion 104 that engages the rear side plate 52 and the rear side plate 53 in this manner, a projection portion 52n is provided to restrict movement of the rear side plate 53 in the direction opposite to the direction of insertion into the rear side plate 52 . As a result, it is possible to prevent the rear plate 53 from moving in the direction opposite to the inserting direction into the rear plate 52 and the rear plate 53 and the rear plate 52 from separating from each other, thereby deteriorating the positional accuracy. Therefore, the rear side plate 53 and the rear side plate 52 that constitute the frame 31 can be assembled with high positional accuracy.

Next, an assembly configuration of the bent portion 52b of the rear plate 52 and the bent portion 53b of the rear plate 53 will be described. FIG. 9 is an enlarged perspective view of the engaging portion between the bent portion 52b of the rear side plate 52 and the bent portion 53b of the rear side plate 53. FIG. Here, FIG. 9(a) shows the state before the rear side plate 52 and the rear side plate 53 are engaged, and FIG. 9(b) shows the state where the rear side plate 52 and the rear side plate 53 are engaged.

As shown in FIG. 9, the bent portion 53b of the rear plate 53 is inserted into and assembled with the bent portion 52b of the rear plate 52. As shown in FIG. The upper part of the bent portion 52b of the rear plate 52 protrudes in the insertion direction (direction of arrow Z) into the bent portion 53b of the rear plate 53, and is bent so as to overlap the bent portion 53b of the rear plate 53 in the plate thickness direction of the rear plate 52. A stepped portion 313 is provided to be inserted into and engaged with the portion 53b. The stepped bent portion 313 is engaged with the rear plate 53 so as to be hooked on the lower end portion of the bent portion 53b of the rear plate 53 .

The stepped bent portion 313 includes a portion bent in the plate thickness direction (arrow X direction) of the bent portion 52b of the rear side plate 52 and a portion bent and extending from the bent portion 52b of the rear side plate 53 in the insertion direction into the bent portion 53b. have The front end portion of the stepped bent portion 313 is formed by bending from a portion of the stepped bent portion 313 that is bent in the direction of insertion into the bent portion 53b of the rear side plate 53, and is formed from the bent portion 52b in the direction of insertion into the bent portion 53b. It is an inclined portion 313a that is inclined in the separating direction.

Two projecting portions 301a and 301b are provided below the bent portion 53b of the rear plate 53 so as to project in the insertion direction (direction of arrow Z) into the bent portion 52b of the rear plate 52. As shown in FIG. The protrusions 301a and 301b are inserted into and engaged with the bent portion 52b of the rear plate 53 so as to overlap the bent portion 52b of the rear plate 53 in the plate thickness direction (the arrow X direction). The projecting portions 301a and 301b are engaged with the bent portion 52b of the rear plate 52 so as to be hooked on the upper end portion of the bent portion 52b. Further, the distal end portions of the projecting portions 301a and 301b are slanted portions 301a1 and 301b1 that are slanted away from the bent portion 53b with respect to the insertion direction of the rear plate 52 into the bent portion 52b.

When the stepped portion 313 is engaged with the bent portion 53b and the projecting portions 301a and 301b are engaged with the bent portion 52b, in the direction perpendicular to the insertion direction of the bent portions 52b and 53b and the plate thickness direction (arrow Y direction), The stepped portion 313 and the projecting portions 301a and 301b are alternately engaged. Specifically, the protruding portion 301a is positioned closer to the support portion 53a of the rear plate 53 than the stepped portion 313 in the orthogonal direction, and at a position adjacent to the stepped portion 313, the bent portion 52b. into and engage. The projecting portion 301b is inserted into and engaged with the bent portion 52b at a position adjacent to the stepped portion 313 and farther from the support portion 53a of the rear plate 53 than the stepped portion 313 in the orthogonal direction. match. With this configuration, the bent portion 52b of the rear plate 52 and the bent portion 53b of the rear plate 53 are firmly engaged and assembled.

Next, as shown in FIG. 10, the middle stay 54 is assembled. The middle stay 54 is an optical stand on which the laser scanner unit 15 is placed. The middle stay 54 is arranged on two pillars 33 c provided on the stand 33 and is inserted into the support portion 53 a of the rear side plate 53 .

The middle stay 54 has a flat portion 54w1 extending in the horizontal direction, and a bent portion 54w2 that is vertically and upwardly bent from the flat portion 54w1 at one end portion of the flat portion 54w1 in the arrow Y direction. The middle stay 54 includes a bent portion 54w3 that is vertically bent from the flat portion 54w1 so as to face the bent portion 54w2, and a bent portion 54w3 that is vertically bent upward from the flat portion 54w1 at one end of the flat portion 54w1 in the direction of the arrow X. It has a curved raised portion 54w4. The middle stay 54 has a bent portion 54w5 that is vertically and downwardly bent from the flat portion 54w1 at the other end portion of the flat portion 54w1 in the direction of the arrow X and further extends horizontally therefrom. A bent portion 54w4 of the middle stay 54 is provided with a protruding portion 54a protruding in the inserting direction (arrow Y direction) with respect to the rear side plate 53. As shown in FIG. The projecting portion 54a of the intermediate stay 54 is formed in the support portion 53a of the rear side plate 53 and is inserted into a through hole 150 passing through the support portion 53a in the plate thickness direction (arrow Y direction). Thereby, the positions of the middle stay 54 in the arrow X direction and the arrow Y direction with respect to the rear side plate 53 are determined.

Next, as shown in FIG. 11, the front side plate 55 is assembled. A middle stay 54 is inserted into the front side plate 55 . The front side plate 55 has a flat portion 55w1 extending in the vertical direction, and a bent portion 55w2 in which both ends of the flat portion 55w1 in the arrow X direction and the arrow Y direction are bent forward of the image forming apparatus A, respectively. The plane portion 55w1 of the front side plate 55 is formed with through holes 55a and 55b penetrating therethrough in the plate thickness direction (the arrow Y direction). The bent and raised portion 54w3 of the middle stay 54 is provided with protruding portions 54b and 54c that protrude in the insertion direction (arrow Y direction) with respect to the front side plate 55. As shown in FIG. A hook portion 54b1 that protrudes upward from the base end portion is provided at the tip portion of the protruding portion 54b.

The protruding portion 54b of the middle stay 54 is inserted into the through hole 55a formed in the flat portion 55w1 of the front side plate 55, and the protruding portion 54c is inserted into the through hole 55b formed in the flat portion 55w1 of the front side plate 55. Thereby, the position of the front side plate 55 with respect to the middle stay 54 is determined. A hook portion 54b1 of the projecting portion 54b faces a portion of the front side plate 55 above the through hole 55a. As a result, the hook portion 54b1 of the middle stay 54 and the flat portion 55w1 of the front side plate 55 come into contact with each other, restricting the movement of the middle stay 54 in the direction opposite to the direction in which it is inserted into the front side plate 55, thereby preventing the middle stay 54 from coming off. done.

Next, as shown in FIG. 12, the left strut 56 is assembled. The left post 56 is arranged on the stand 33 . A front side plate 55 is inserted into the left strut 56 . The left strut 56 is mainly formed of two planes, a plane portion 56w1 extending parallel to the plane portion 55w1 of the front side plate 55, and a plane portion 56w2 bent substantially perpendicularly to the rear of the image forming apparatus A from the plane portion 56w1. have. A through-hole 56a penetrating in the arrow Y direction is provided in the bent portion of the boundary between the flat portion 56w1 and the flat portion 56w2 of the left support 56 . A through-hole 56b is provided in the plane portion 56w2 of the left column 56 so as to penetrate in the plate thickness direction (the arrow X direction). The bent and raised portion 55w2 of the front side plate 55 is provided with a projecting portion 55c projecting in the insertion direction (arrow Y direction) into the left strut 56 and a projecting portion 55d projecting in the plate thickness direction (arrow X direction). .

A protruding portion 55 c of the front side plate 55 is inserted into a through hole 56 a formed in the left strut 56 . Thereby, the position of the left strut 56 with respect to the front side plate 55 is determined. Further, the protrusion 55d of the front side plate 55 is engaged with the through hole 56b of the left strut 56. As shown in FIG. As a result, the edge 55d1 of the protrusion 55d comes into contact with the inner wall of the through hole 56b, and movement of the front side plate 55 in the direction opposite to the insertion direction of the left support 56 is restricted.

Next, as shown in FIG. 13, the front lower stay 57 is assembled. The front lower stay 57 is arranged on the stand 33 and is inserted into and assembled with the left strut 56 . The front lower stay 57 has a flat portion 57w1 which is a flat surface to be placed on the table 33, and both ends of the flat portion 57w1 in the directions of the arrows X and Y are bent substantially vertically and upward from the flat portion 57w1. It has a bent up portion 57w2. A bent portion 57w2 of the front lower stay 57 is provided with a protruding portion 57a that protrudes in the insertion direction (arrow X direction) with respect to the left strut 56. As shown in FIG. The plane portion 57w1 of the front lower stay 57 is formed with a positioning hole 57b penetrating in the plate thickness direction (arrow Z direction). A through-hole 56c is formed in the plane portion 56w2 of the left column 56 so as to penetrate in the plate thickness direction (the arrow X direction). Here, the width of the upper end of the through hole 56c is L1, and the width of the lower end thereof is L2. Further, the width of the tip portion of the projecting portion 57a is L3, and the width of the substrate portion is L4. At this time, the relationships are L1>L2, L4<L3, L1≈L3, and L2≈L4.

The projecting portion 57a of the front lower stay 57 is inserted into and engaged with the through hole 56c formed in the flat portion 56w2 of the left strut 56. As shown in FIG. At this time, the projecting portion 57a is inserted from the upper side of the through hole 56c, and then moved to the lower end portion of the through hole 56c by the force or gravity of the assembling operator. Here, when the projecting portion 57a is positioned at the lower end portion of the through hole 56c, the movement of the projecting portion 57a in the direction opposite to the inserting direction into the through hole 56c is restricted due to the relationship of L3>L2. When the front lower stay 57 is arranged on the mounting table 33 , the positioning pin 33 b of the mounting table 33 is inserted into the positioning hole 57 b of the front lower stay 57 . Thereby, the position of the front lower stay 57 with respect to the mounting table 33 is determined.

Next, as shown in FIG. 14, the right strut 58 is assembled. The right post 58 is arranged on the stand 33 . Also, the front side plate 55 is inserted and assembled to the right strut 58 . The right post 58 has a plane portion 58w1 extending parallel to the plane portion 55w1 of the front side plate 55, and a plane portion 58w2 bent substantially perpendicularly forward of the image forming apparatus A from the plane portion 58w1. The assembly structure of the right strut 58 and the front side plate 55 is the same as the assembly structure of the left strut 56 and the front side plate 55 . In other words, a through-hole (not shown) penetrating in the arrow Y direction is formed in the bent portion of the boundary between the plane portion 58w1 and the plane portion 58w2 of the right post 58 . A projecting portion (not shown) formed on the bent and raised portion 55w2 of the front side plate 55 and projecting in the inserting direction (arrow Y direction) with respect to the right post 58 is inserted into the through hole. A through hole (not shown) is formed in the plane portion 58w2 of the right post 58 so as to penetrate in the plate thickness direction (the arrow X direction). A protrusion (not shown) formed on the bent portion 55w2 of the front side plate 55 and protruding in the direction of the arrow X is engaged with the through hole.

The frame body 31 can be self-supporting at the time when it is assembled so far. That is, the front side plate 55, the right column 58, the left column 56, and the front lower stay 57 which are the frame 31 on the front side of the image forming apparatus A; The frame 31 can stand on its own by assembling the middle stay 54, which is the frame 31 that connects the frame on the front side and the frame on the back side.

Next, as shown in FIG. 15, the lower left stay 59 is assembled. The left lower stay 59 has a flat portion 59w1 extending parallel to the flat portion 56w2 of the left strut 56, and a bent portion 59w2 bent in the plate thickness direction (arrow X direction) of the flat portion 59w1 above the flat portion 59w1. The lower left stay 59 is assembled by inserting it into the rear side plate 52 and the left strut 56 from the vertical direction. The assembly structure of the left lower stay 59 and the left strut 56 and the assembly structure of the left lower stay 59 and the rear side plate 52 are the same. Therefore, only the assembly structure of the left lower stay 59 and the left strut 56 will be described here.

The flat portion 56w2 of the left strut 56 has a protruding portion 56g and a stepped portion 56j protruding in the inserting direction (arrow Z direction) into the left lower stay 59, and a projection protruding in the plate thickness direction (arrow X direction) of the flat portion 56w2. A portion 56h is provided. The stepped bent portion 56j has a portion bent in the plate thickness direction of the planar portion 56w2 and a portion bent and extending from the bent portion in the direction of insertion into the lower left stay 59. As shown in FIG. The tip of the stepped portion 56j is an inclined portion 56j1 that is inclined away from the flat portion 56w2 with respect to the insertion direction of the left strut 56 into the lower left stay 59. As shown in FIG. A flat portion 59w1 of the lower left stay 59 is formed with a through hole 59a penetrating in the plate thickness direction (arrow X direction) and a notch portion 59b cut in the plane direction.

The projecting portion 56g of the left strut 56 is inserted into and engaged with a through hole 59a formed in the flat portion 59w1 of the lower left stay 59. As shown in FIG. Here, the width of the projecting portion 56g in the direction of the arrow Y and the width of the through hole 59a in the direction of the arrow Y are substantially the same width. Therefore, the position of the left lower stay 59 with respect to the left strut 56 in the arrow Y direction is determined by inserting the projecting portion 56g into the through hole 59a.

The stepped portion 56j of the left strut 56 is inserted into and engaged with the lower end portion of the flat portion 59w1 of the lower left stay 59. As shown in FIG. As a result, the flat portion 59w1 of the lower left stay 59 is sandwiched between the stepped portion 56j and the flat portion 56w2 of the left support 56 in the plate thickness direction (direction of arrow X), and the position of the lower left stay 59 in the direction of arrow X relative to the left support 56 is determined. be done.

A projection 56 h of the left strut 56 is engaged with a notch 59 b formed in the lower left stay 59 . As a result, the edge 56h1 of the protrusion 56h contacts the inner wall of the notch 59b, and movement of the left support 56 in the direction opposite to the insertion direction of the left lower stay 59 is restricted.

Next, as shown in FIG. 16, the upper left stay 60 is assembled. The rear side plate 53 and the left strut 56 are inserted into and assembled with the upper left stay 60 . The assembly structure of the upper left stay 60 and the rear side plate 53 and the assembly structure of the upper left stay 60 and the left strut 56 are the same. Therefore, here, the assembly structure of the left upper stay 60 and the left strut 56 will be mainly described.

The upper left stay 60 (first support) is a plate-shaped member that extends parallel to the flat portion 56w2 of the left support 56, and has a surface 60w1 facing the outside of the image forming apparatus A and a surface 60w1 facing the inside of the image forming apparatus A. It has a back surface 60w2 behind the front surface 60w1. A through-hole 60a (first through-hole) and a through-hole 60b (second through-hole) are formed in the upper left stay 60 so as to pass through the front surface 60w1 and the rear surface 60w2 in the plate thickness direction (arrow X direction). there is The through holes 60a and 60b are formed at different positions in the same plane of the upper left stay 60, and the through hole 60b is formed vertically above the through hole 60a.

A flat portion 56w2 of the left strut 56 (second support) is provided with an insertion portion 56d that is bent toward the rear surface 60w2 of the upper left stay 60. As shown in FIG. The flat portion 56w2 on which the insertion portion 56d of the left strut 56 is formed is a surface (second portion) extending parallel to the surface (first portion) on which the through holes 60a and 60b of the upper left stay 60 are formed. . The insertion portion 56d of the left strut 56 is inserted into and engaged with the through holes 60a and 60b formed in the upper left stay 60. As shown in FIG. As a result, the left upper stay 60 is attached to the left strut 56 .

The bent portion 53b of the rear side plate 53 is also provided with an insertion portion 53z having the same shape as the insertion portion 56d of the left strut 56. As shown in FIG. The insertion portion 53z of the rear side plate 53 is inserted into and engaged with the through hole 60z of the upper left stay 60 in the same manner as the insertion portion 56d of the left strut 56 . As a result, the upper left stay 60 is assembled to the rear side plate 53 .

17A is a plan view of the through holes 60a and 60b of the upper left stay 60. FIG. As shown in FIG. 17A, the inner wall of the through hole 60a is provided with protrusions 60a1 to 60a3 projecting inwardly of the through hole 60a. With respect to the direction perpendicular to the plate thickness direction and the vertical direction of the upper left stay 60 (direction of arrow Y), the portion between the tip of the protrusion 60a3 and the straight line connecting the tips of the protrusions 60a1 and 60a2 is the portion of the through hole 60a. This is the portion with the minimum width, and the width L5 and the plate thickness of the flat portion 56w2 of the left strut 56 are approximately the same width.

17(b) is a plan view of the insertion portion 56d of the left strut 56. FIG. An engaging portion 56d1 that is inserted into and engaged with the through hole 60b of the upper left stay 60 is provided at the tip of the insertion portion 56d. A lower portion of the tip portion of the engaging portion 56d1 is an inclined portion 56d1x. The insertion portion 56d includes a contact portion 56d2 that contacts the portion between the through holes 60a and 60b of the upper left stay 60, and a fitting portion that fits into the minimum width portion of the through hole 60a. 56d3 is provided. Here, since the fitting portion 56d3 is a member that is bent from the flat portion 56w2 of the left column 56 made of a metal plate, the plate thickness of the flat portion 56w2 and the plate thickness of the fitting portion 56d3 are equal. .

18A to 18C are diagrams showing how the upper left stay 60 is assembled to the left strut 56 in the order shown in FIGS. 18(a) to 18(c). As shown in FIGS. 18(a) and 18(b), when the upper left stay 60 is assembled, first, the insertion portion 56d of the left support 56 is inserted into the through hole 60a of the upper left stay 60 so that the plate thickness of the upper left stay 60 is larger than that of the upper left stay 60. It is inserted from the direction (arrow X direction). Specifically, the insertion portion 56d of the left strut 56 is inserted into the through hole 60a in the direction of the arrow X, from the rear surface 60w2 of the upper left stay 60 toward the front surface 60w1.

Next, as shown in FIG. 18(c), the upper left stay 60 is moved downward in the vertical direction (direction of arrow Z). As a result, the through hole 60b of the left strut 56 approaches the engaging portion 56d1 of the insertion portion 56d. After that, when the upper left stay 60 is further moved downward in the vertical direction, the engaging portion 56d1 of the insertion portion 56d is in the direction of the arrow X with respect to the through hole 60b, and moves from the front surface 60w1 to the rear surface 60w2 of the upper left stay 60. It is inserted in the facing direction and engaged. That is, the engaging portion 56d1 of the insertion portion 56d is engaged by being inserted into the through hole 60b from the opposite direction to the insertion direction of the insertion portion 56d into the through hole 60a while the insertion portion 56d is inserted into the through hole 60a. match. As a result, the left strut 56 and the upper left stay 60 are assembled, resulting in the state shown in FIG. 16(b).

As shown in FIG. 18(c), although the engaging portion 56d1 and the upper inner wall of the through hole 60a are in contact with each other at the contact point P, the inclined portion 56d1x is formed in the engaging portion 56d1. The portion 56d1 can climb over the upper inner wall of the through hole 60a. Further, the engaging portion 56d1 receives a reaction force from the upper left stay 60 at a position between the through-holes 60a and 60b and is elastically deformed. back to

Further, when the insertion portion 56d is inserted into the through hole 60a and the engaging portion 56d1 is engaged with the through hole 60b, the contact portion 56d2 of the insertion portion 56d contacts the through hole 60a on the surface 60w1 of the upper left stay 60 and the through hole. 60b. As a result, the upper left stay 60 is held between the flat portion 56w2 and the contact portion 56d2 of the left strut 56 in the plate thickness direction (arrow X direction). By clamping the upper left stay 60 in this way, the movement of the upper left stay 60 with respect to the left strut 56 in the direction of the arrow X is regulated. Therefore, it is possible to prevent deterioration of the positional accuracy due to the separation of the upper left stay 60 and the left support 56, and the upper left stay 60 and the left support 56 constituting the frame 31 can be assembled with high positional accuracy.

When the insertion portion 56d is inserted into the through-hole 60a and the engaging portion 56d1 is engaged with the through-hole 60b, the projections 60a1 to 60a3 (to-be-fitted portions) of the through-hole 60a are engaged with the insertion portion 56d. 56d3 fits. That is, since the width L5 and the plate thickness of the flat portion 56w2 of the left column 56 are substantially the same, the fitting portion 56d3 is fitted to the convex portions 60a1 to 60a3. As a result, the fitting portion 56d3 is sandwiched between the convex portions 60a1 to 60a3, and the position of the upper left stay 60 in the direction of the arrow Y with respect to the left strut 56, that is, the position of the upper left stay 60 in the planar direction is determined.

In addition to the insertion portion 56d and the through holes 60a and 60b, a configuration in which the upper left stay 60 and the left strut 56 are engaged with each other may be provided. 19A and 19B are diagrams showing other configurations of the left strut 56 and the upper left stay 60. FIG. Here, FIG. 19(a) shows the state before the left strut 56 and the upper left stay 60 are assembled, and FIG. 19(b) shows the state after the left strut 56 and the upper left stay 60 are assembled.

As shown in FIG. 19(a), the upper left stay 60 is provided with a through hole 60c penetrating in the plate thickness direction (the arrow X direction). The through-hole 60c is formed on the same surface as the through-holes 60a and 60b of the upper left stay 60, and specifically, is formed above the through-hole 60b in the vertical direction. A protrusion 60c1 that protrudes toward the inside of the through hole 60c is formed on the inner wall of the through hole 60c.

A flat portion 56w2 of the left post 56 is provided with an insertion portion 56e (another insertion portion) that is inserted and fitted into the through hole 60c. The insertion portion 56e is formed by bending from the flat portion 56w2 of the left support 56. As shown in FIG. The flat portion 56w2 extends parallel to the surface of the upper left stay 60 in which the through holes 60a to 60c are formed.

As shown in FIG. 19B, the insertion portion 56e of the left strut 56 is inserted into the through hole 60c of the upper left stay 60 from the thickness direction of the upper left stay 60 (the arrow X direction). Specifically, the insertion portion 56e of the left strut 56 is inserted into the through hole 60c in the direction of the arrow X, from the rear surface 60w2 of the upper left stay 60 toward the front surface 60w1. Thereafter, as the upper left stay 60 moves downward in the vertical direction, the insertion portion 56e contacts the upper inner wall of the through hole 60c and engages with the through hole 60c in this state. Such a configuration increases the number of engagement points between the upper left stay 60 and the left strut 56, so that they can be assembled more stably.

Also, by adjusting the projection amount of the convex portion 60c1 of the left upper stay 60, a part (other fitting portion) of the insertion portion 56e of the left strut 56 is aligned with the convex portion 60c1 of the through hole 60c and the inner wall of the through hole 60c (other fitting portion). It is good also as a structure fitted to the to-be-fitted part). That is, the distance between the convex portion 60c1 of the through hole 60c and the inner wall of the through hole 60c facing the convex portion 60c1 is made equal to the plate thickness of the upper left stay 60. As shown in FIG. As a result, the insertion portion 56e is sandwiched between the inner walls of the through hole 60c, and the upper left stay 60 is positioned with respect to the left support 56 in the direction perpendicular to the plate thickness direction and the vertical direction (arrow Y direction).

Next, as shown in FIG. 20, the lower right stay 61 is assembled. The lower right stay 61 is a member that connects the rear plate 52 and the right strut 58 facing each other, and is inserted horizontally (in the direction of the arrow Y) into the rear plate 52 and the right strut 58 from the same direction. can be assembled. The lower right stay 61 is a member that ensures the conveyability of the sheet S. As shown in FIG. Moreover, since it is positioned near the corners of the frame 31 , it affects the rigidity of the frame 31 . Therefore, it is particularly desirable that the lower right stay 61 is assembled with high positional accuracy. The assembly configuration of the lower right stay 61 will be described in detail below.

FIG. 21 is a perspective view of the lower right stay 61, the rear side plate 52, and the right strut 58. FIG. FIG. 22 is an enlarged perspective view of the engaging portion between the lower right stay 61 and the rear side plate 52. FIG. FIG. 23 is an enlarged perspective view of the engaging portion between the lower right stay 61 and the right support 58. FIG. Here, FIGS. 21(a), 22(a) and 23(a) show the state before the right lower stay 61 is assembled, and FIGS. 21(b), 22(b) and 23(b). ) shows the state in which the lower right stay 61 is assembled.

First, the assembly structure of the lower right stay 61 and the rear side plate 52 will be described. As shown in FIGS. 21 and 22, the flat portion 52a of the rear plate 52 is provided with a bent portion 250 that is bent in the direction of arrow Y. As shown in FIGS. In addition, in the plane portion 52a of the rear side plate 52, a through hole 251 is formed around the bent portion 250 so as to pass through the plane portion 52a in the plate thickness direction (arrow Y direction). As described above, the rear plate 52 is formed from a single sheet metal, and the through hole 251 is a hole formed when the bent portion 250 is formed.

The lower right stay 61 is composed of three planes. The lower right stay 61 has a flat portion 61w1 extending substantially parallel to the bent portion 52w of the rear side plate 52, and a flat portion 61w2 bent substantially perpendicularly in the arrow X direction from the flat portion 61w1 above the flat portion 61w1. Further, the lower right stay 61 has a flat portion 61w2 bent to face the flat portion 61w2 under the flat portion 61w1. A flat portion 52w1 of the lower right stay 61 is provided with a stepped bent portion 61a that is inserted into and engaged with the bent portion 250 of the rear side plate 52 . The stepped bent portion 61a includes a portion bent in the plate thickness direction (arrow X direction) of the flat portion 52w1 of the lower right stay 61, and a portion bent in the insertion direction (arrow Y direction) into the rear side plate 52 and extending from that portion. have a part that

When the lower right stay 61 is assembled, the entire one end of the lower right stay 61 in the direction of the arrow Y is inserted into the through hole 251 of the rear plate 52 , and the stepped portion 61 a of the lower right stay 61 is bent into the rear plate 52 . It plugs into and engages portion 250 . As a result, the bent portion 250 of the rear plate 52 is sandwiched from the plate thickness direction (arrow X direction) by the step bent portion 61a and the flat portion 61w1 of the lower right stay 61, and the position of the lower right stay 61 with respect to the rear plate 52 in the arrow X direction. is determined.

A flat portion 61w2, which is the upper surface of the lower right stay 61, and an upper inner wall of the through hole 251 of the rear side plate 52 are opposed to each other with a predetermined gap therebetween. The inner walls on the lower side of 251 face each other with a predetermined gap. As a result, the position of the lower right stay 61 in the vertical direction (in the direction of the arrow Z) with respect to the rear side plate 52 is determined with a play of a predetermined distance.

Next, the assembly structure of the lower right stay 61 and the right strut 58 will be described. As shown in FIGS. 21 and 23, the flat portion 58w2 of the right post 58 is formed with an insertion hole 58a into which the stepped portion 61b of the lower right stay 61 is inserted. The right post 58 also has a flat portion 58w3 extending rearward of the image forming apparatus A in the arrow Y direction from the periphery of the insertion hole 58a in the flat portion 58w2. The planar portion 58w3 is provided with a substantially semicircular protruding portion 58b that protrudes in the plate thickness direction (arrow X direction). The projecting portion 58b is formed by drawing, and is arranged at a position adjacent to the insertion hole 58a in the insertion direction (arrow Y direction) of the stepped portion 61b into the insertion hole 58a.

A flat portion 61w1 of the lower right stay 61 is provided with a stepped portion 61b that is inserted into and engaged with the insertion hole 58a of the right support 58 . The stepped portion 61b has a portion that is bent in the plate thickness direction (arrow X direction) of the flat portion 61w1 and a portion that is bent and extends from the bent portion in the insertion direction (arrow Y direction) into the right support 58 .

A through hole 61c is formed around the stepped portion 61b of the flat portion 61w1 of the lower right stay 61 so as to pass through the flat portion 61w1 in the plate thickness direction. The through hole 61c is arranged at a position adjacent to the stepped portion 61b in the insertion direction of the right lower stay 61 into the right support 58 . As described above, the lower right stay 61 is made of a single sheet metal, and the through hole 61c is formed when the stepped portion 61b is formed.

When the lower right stay 61 is assembled, the stepped portion 61b of the lower right stay 61 is inserted into and engaged with the insertion hole 58a of the right support 58, and the projection 58b of the right support 58 passes through the lower right stay 61. It engages with hole 61c. By engaging the stepped portion 61b with the insertion hole 58a in this manner, the positions of the lower right stay 61 with respect to the right support 58 in the directions of the arrows X and Y are determined. The upper surface of the stepped portion 61b and the upper inner wall of the insertion hole 58a face each other with a predetermined gap, and the lower surface of the stepped portion 61b and the lower inner wall of the insertion hole 58a face each other with a predetermined gap. do. As a result, the position of the lower right stay 61 in the vertical direction (in the direction of the arrow Z) with respect to the right strut 58 is determined with a play of a predetermined distance.

In the process of inserting the stepped portion 61b into the insertion hole 58a, the lower right stay 61 rides up by the height of the tip portion of the projecting portion 58b. At this time, although a force is temporarily applied to the stepped portion 61b in the direction in which the stepped portion 61b opens, the height of the tip of the protrusion 58b is within a range where the stepped portion 61b is deformed in the elastic region. is set to the height of

When the lower right stay 61 is engaged with the rear plate 52 and the right post 58, the protrusion 58b contacts the inner wall 61d of the through hole 61c, thereby inserting the lower right stay 61 into the rear plate 52 and the right post 58. Movement in the opposite direction is restricted. In other words, in order to remove the lower right stay 61 from the rear side plate 52 and the right support 58, the plate thickness direction of the flat portion 61w1 of the lower right stay 61 and the insertion direction of the lower right stay 61 into the rear side plate 52 and the right support 58 are opposite. It is necessary to apply force in two directions to the lower right stay 61 .

Here, the length (distance) of each portion of the lower right stay 61 in the insertion direction (arrow Y direction) with respect to the rear side plate 52 and the right strut 58 is defined as follows. That is, the engaging length of the stepped portion 61a shown in FIG. 22 with respect to the bent portion 250 is L6, and the engagement length of the stepped portion 61b shown in FIG. When the stepped portion 61a is engaged with the bent portion 250 and the stepped portion 61b is engaged with the insertion hole 58a, the distance between the tip of the projection 58b and the inner wall 61d of the through hole 61c shown in FIG. is the distance L8.

At this time, the relationship among L6, L7, and L8 is L6>L7>L8. As a result, the lower right stay 61 moves in the direction opposite to the insertion direction with respect to the rear side plate 52 and the right strut 58, and when the protrusion 58b comes into contact with the inner wall 61d of the through hole 61c and the movement is restricted, the stepped portion 61a , 61b, the bent portion 250, and the insertion hole 58a are kept engaged. Therefore, the lower right stay 61 is prevented from being separated from the rear plate 52 and the right support 58, and deterioration of the positional accuracy between the lower right stay 61, the rear plate 52 and the right support 58 can be suppressed.

Further, by setting the relationship of L6>L7, when the lower right stay 61 is assembled, the stepped bent portion 61a having a relatively long engagement length and the bent portion 250 are engaged first, and the engagement length is relatively short. The engagement between the stepped portion 61b and the insertion hole 58a is performed later. By providing a difference in engagement length in this manner, the order in which the lower right stay 61 is assembled can be determined, and workability during assembly can be improved.

The engagement length of the insertion direction of the rear plate 52 into the through hole 251 at one end of the lower right stay 61 in the arrow Y direction is L9. In this case, the maximum engagement length of the lower right stay 61 with respect to the rear side plate 52 in the insertion direction is L9. That is, the relationship between L6 and L9 is L9>L6>L7>L8.

Next, as shown in FIG. 24, the rear side plate 62 is assembled. The rear side plate 62 is inserted into the rear side plate 53 from the arrow Z direction and assembled. The assembly structure of the rear side plate 62 and the rear side plate 53 is the same as the assembly structure of the rear side plate 52 and the rear side plate 53, and both are inserted and engaged with each other.

Next, as shown in FIG. 25, the right middle stay 65 is assembled. The right center stay 65 is a plate-like member formed in one plane. The right center stay 65 is inserted into and assembled with the rear side plate 53 and the right support column 58 . The assembling structure of the right middle stay 65 and the rear side plate 53 and the assembling structure of the right middle stay 65 and the right strut 58 are the same. Therefore, here, the assembly structure of the right center stay 65 and the rear side plate 53 will be mainly described.

The support portion 53a of the rear side plate 53 is formed with a through hole 53c penetrating in the plate thickness direction (arrow Y direction). In addition, the rear side plate 53 is a member extending in the vertical direction. The right middle stay 65 is provided with a protrusion 65a that protrudes in the insertion direction (arrow Y direction) into the support portion 53a of the rear side plate 53 and is inserted into the through hole 53c of the rear side plate 53 from the arrow Y direction.

The projecting portion 65a is provided with a base portion 65a1 that fits into the through-hole 53c, and a distal end side of the insertion direction from the base portion 65a1. It has a hook portion 65a2. It also has a sloped portion 65a3 that slopes down from the upper end of the base portion 65a1 to the upper end of the hook portion 65a2.

When the protruding portion 65a is inserted into the through hole 53c, the hook portion 65a2, which is the tip portion of the protruding portion 65a, is inserted first, and then the base portion 65a1 is inserted, and the base portion 65a1 is fitted into the through hole 53c. The vertical width of the base portion 65a1 of the projecting portion 65a and the vertical width of the through hole 53c are substantially the same. The plate thickness of the right middle stay 65 and the width of the through hole 53c in the direction of the arrow X are substantially the same width. Therefore, by fitting the base portion 65a1 of the protruding portion 65a into the through hole 53c, the position of the right center stay 65 in the vertical direction (direction of arrow Z) with respect to the rear side plate 53 and the insertion direction with respect to the rear side plate are orthogonal to the vertical direction. The position of the direction (arrow X direction) is determined.

Further, when the base portion 65a1 of the protruding portion 65a is fitted in the through hole 53c, the lower end portion 65a2x of the hook portion 65a2 is positioned to face the portion of the support portion 53a of the rear side plate 53 below the through hole 53c. do. As a result, the hooking portion 65a2 is caught by the support portion 53a, and movement of the rear side plate 53 of the right middle stay 65 in the direction opposite to the insertion direction with respect to the support portion 53a is restricted. Therefore, the right middle stay 65 and the rear side plate 53 can be assembled with high positional accuracy without separating the right middle stay 65 from the rear side plate 53 .

Next, as shown in FIG. 26, the right strut 63 is assembled. The right post 63 has a flat portion 63w1 extending parallel to the flat portion 55w1 of the front side plate 55, a flat portion 63w2 bent substantially perpendicularly in the direction of arrow Y from the flat portion 63w1, and facing the flat portion 63w1 from the flat portion 63w2. It has a flat portion 63w3 that is bent substantially vertically. The right strut 63 is inserted into and assembled with the right strut 58 .

FIG. 27 is an enlarged perspective view of the engagement portion between the right strut 63 and the right strut 58. FIG. Here, FIG. 27(a) shows the state before the right strut 63 and the right strut 58 are assembled, and FIG. 27(b) shows the state where the right strut 63 and the right strut 58 are assembled.

As shown in FIG. 27, the flat portion 63w2 of the right post 63 has a protrusion 63a protruding in the plate thickness direction (arrow X direction) of the flat portion 63w2 and a protrusion 63a protruding in the insertion direction (arrow Z direction) into the right post 58. Two projecting portions 63b are provided. The projecting portion 63a is formed by drawing, and the amount of projection from the surface of the flat portion 63w2 is about 0.3 mm to 2 mm. The tip of the projecting portion 63b forms an inclined portion 63b1 that is inclined away from the flat portion 63w2 with respect to the insertion direction of the right support 63 into the right support 58. As shown in FIG.

A flat portion 58w2 of the right strut 58 is provided with a stepped portion 58c that protrudes in the direction in which the right strut 58 is inserted into the right strut 63 (direction of arrow Z). A through hole 58d is formed through the flat portion 58w2 in the plate thickness direction (arrow X direction) at a position adjacent to the stepped portion 58c in the insertion direction of the right support 58 into the right support 63. As shown in FIG. The stepped bent portion 58c has a portion bent in the plate thickness direction of the flat portion 58w2 and a portion bent and extending from the bent portion in the insertion direction with respect to the right strut 63 . The tip of the stepped portion 58c is an inclined portion 58c1 that is inclined away from the flat portion 58w2 with respect to the direction in which the right support 58 is inserted into the right support 63. As shown in FIG.

When the right strut 63 is assembled to the right strut 58, the inclined portion 58c1 of the stepped portion 58c of the right strut 58 contacts the flat portion 63w2 of the right strut 63, and the inclined portion 63b1 of the projecting portion 63b of the right strut 63 contacts the right strut. It abuts on the flat portion 58w2 of 58 . As a result, the movement of the right column 63 and the right column 58 in the direction of the arrow Z is guided, and the plane portions 63w2 and 58w2 move in a predetermined positional relationship. Also, the lower end of the stopper portion 63c of the right post 63 hits the abutting portion 58e, which is the upper end of the flat portion 58w2 of the right post 58, so that the right post 63 is inserted into the right post 58 (direction of arrow Z). movement is restricted.

When the right post 63 is assembled to the right post 58, the stepped portion 58c of the right post 58 is inserted into the flat portion 63w2 of the right post 63 and engaged with the lower end of the flat portion 63w2. As a result, the flat portion 63w2 of the right support 63 is sandwiched from the plate thickness direction (direction of arrow Y) by the stepped portion 58c and the flat portion 58w2 of the right support 58, and the position of the right support 63 in the direction of arrow Y relative to the right support 58 is determined. be done.

Also, the protrusion 63 a of the right support 63 is engaged with the through hole 58 d formed in the right support 58 . As a result, the edge 63a1 of the protrusion 63a comes into contact with the inner wall of the through hole 58d, and movement of the right support 63 in the direction opposite to the insertion direction of the right support 58 is restricted. Here, the through hole 58d is arranged at a position adjacent to the stepped portion 58c in the insertion direction of the right support 58 into the right support 63 . Therefore, the projecting portion 63a engaged with the through hole 58d and the stepped portion 58c are arranged at positions adjacent to each other in the insertion direction.

In addition, in the direction (arrow Y direction) orthogonal to the plate thickness direction of the flat portion 63w2 and the direction of insertion into the right support 58, the two projecting portions 63b of the right support 63 sandwich the stepped portion 58c of the right support 58. It engages with the stepped portion 58c. This determines the position of the right strut 63 with respect to the right strut 58 in the orthogonal direction.

In the vicinity of the stepped portion 58c that engages the flat portion 63w2 of the right post 63 and the flat portion 58w2 of the right post 58 in this way, a protrusion that restricts movement of the right post 63 to the right post 58 in the direction opposite to the insertion direction is provided. A portion 63a is provided. As a result, it is possible to prevent the right post 63 from moving in the direction opposite to the insertion direction with respect to the right post 58 and the right post 63 and the right post 58 from separating from each other, thereby reducing positional accuracy. Therefore, the right strut 63 and the right strut 58 that constitute the frame 31 can be assembled with high positional accuracy.

Next, as shown in FIG. 28, the upper right stay 64 is assembled. The upper right stay 64 includes a flat portion 64w1 extending in the horizontal direction, a flat portion 64w2 in which one end portion of the flat portion 64w1 in the direction of the arrow X is bent substantially vertically, and one end portion in the direction of the arrow Y extending substantially vertically. It has a flat portion 64w3 that is vertically bent. The upper right stay 64 also has a flat portion (not shown) in which the other end portion of the flat portion 64w1 in the direction of the arrow Y is bent substantially perpendicularly to the vertical direction. The upper right stay 64 is inserted into and assembled with the rear side plate 62 and the right strut 63 . The assembly structure of the upper right stay 64 and the rear side plate 62 and the assembly structure of the upper right stay 64 and the right strut 63 are the same. Therefore, only the assembly structure of the upper right stay 64 and the right strut 63 will be described here.

The flat portion 64w3 of the upper right stay 64 is composed of three bent portions 304a, 304b, and 304c that are bent from the flat portion 64w1 toward the inserting direction (direction of arrow Z) into the right strut 63. As shown in FIG. That is, when the plane portion 64w3 is divided into three portions in the direction of the arrow X, there are bent portions 304a, 304b, and 304c. The bent portion 304c is located between the bent portions 304a and 304b in the direction of arrow X, and the length of the bent portion 304c in the direction of arrow Z is greater than the length of the bent portions 304a and 304b in the direction of arrow Z. is also shorter. The bent portions 304a and 304b have the same length in the direction of the arrow Z, and the distal end portions of the bent portions 304a and 304b are inclined in the direction away from the flat portion 64w1 with respect to the inserting direction of the right strut 63. 304a1 and 304b1.

The flat portion 63w3 of the right post 63 protrudes in the insertion direction into the upper right stay 64, and is inserted into the upper right stay 64 so as to overlap the bent portion 304c of the upper right stay 64 in the plate thickness direction (arrow Y direction) of the flat portion 63w3. A mating step 316 is provided. In addition, the flat portion 63w2 of the right post 63 protrudes in the insertion direction with respect to the upper right stay 64, and is inserted into the flat portion 64w2 so as to overlap the flat portion 64w2 of the upper right stay 64 in the plate thickness direction (arrow X direction) of the flat portion 63w2. A stepped portion 325 is provided that engages the A flat portion 63w2 of the right post 63 is provided with a protrusion 330 that protrudes in the plate thickness direction (the arrow X direction).

The stepped bent portion 316 extends from a portion bent in the plate thickness direction (arrow Y direction) of the flat portion 63w3 of the right strut 63 and bent in the insertion direction (arrow Z direction) into the upper right stay 64 from that portion. have a part. The tip of the stepped portion 316 is further bent from the portion of the stepped portion 316 that is bent in the direction of insertion into the upper right stay 64, and is formed in a direction away from the flat portion 63w3 with respect to the direction of insertion into the upper right stay 64. It becomes the inclined part 316a which inclines.

The stepped portion 325 extends from a portion bent in the plate thickness direction (arrow X direction) of the flat portion 63w2 of the right strut 63 and bent in the insertion direction (arrow Z direction) into the upper right stay 64 from that portion. have a part. The tip of the stepped portion 325 is further bent from the portion of the stepped portion 325 that is bent in the direction of insertion into the upper right stay 64, and is formed in a direction away from the flat portion 63w2 with respect to the direction of insertion into the upper right stay 64. It becomes the inclination part 325a which inclines.

When the upper right stay 64 is assembled to the right post 63, the inclined portions 316a and 325a of the stepped bent portions 316 and 325 of the right post 63 abut against the upper right stay 64, and the inclined portions 304a1 and 304a1 of the bent portions 304a and 304b of the upper right stay 64 304b1 abuts on the right post 63; As a result, the movement of the upper right stay 64 and the right strut 63 is guided, and both move in a predetermined positional relationship.

When the stepped bent portion 316 engages the bent portion 304c of the upper right stay 64 and the bent portions 304a and 304b engage the flat portion 63w3 of the right support 63, the right support 63 and the upper right stay 64 are inserted in the insertion direction and the plate thickness direction. In the orthogonal direction (direction of arrow X), the stepped bent portion 316 and the bent portions 304a and 304b are alternately engaged. Specifically, the bent portion 304a engages with the flat portion 63w3 of the right post 63 at a position adjacent to the stepped bent portion 316 in the arrow X direction. In addition, the bent portion 304b is formed on the flat portion 63w3 of the right post 63 at a position adjacent to the stepped bent portion 316 and on the side opposite to the bent portion 304a with respect to the stepped bent portion 316 in the arrow X direction. engage. With such a configuration, the upper right stay 64 and the right strut 63 are firmly engaged and assembled.

The protrusion 330 of the right strut 63 is formed in the plane portion 64w2 of the upper right stay 64 and engages with a through hole 335 penetrating the plane portion 64w2 in the plate thickness direction (arrow X direction). As a result, the edge 330a of the protrusion 330 comes into contact with the inner wall of the through hole 335, and movement of the upper right stay 64 in the direction opposite to the insertion direction of the right support 63 is restricted.

As described above, each sheet metal forming the frame 31 is assembled. The frame 31 assembled in the assembly process as described above is configured to be self-supporting. Therefore, the frame 31 can be removed from the stand 33 by grasping the rear plate 52, the left strut 56, the right strut 58, etc. of the frame 31 and lifting the frame 31. As shown in FIG.

<Bonding process of frame>
Next, a process of joining the frame 31 assembled in the above-described assembly process will be described.

FIG. 29 is a perspective view of a jig 34 used for joining the frame 31. FIG. As shown in FIG. 29, the jig 34 has a base 34a, a front support portion 34b, and a rear support portion 34c. A positioning pin 34a1 is provided on the base 34a. The front side support portion 34b and the rear side support portion 34c are configured to be slidable with respect to the base 34a. The front side support portion 34b is slidable in the directions of arrows K1 and K2, and the rear side support portion 34c is slidable in the directions of arrows K3 and K4.

FIG. 30 is a perspective view of the frame 31 and the jig 34 assembled in the assembly process described above. As shown in FIG. 30, the frame body 31 is removed from the stand 33 and placed on the base 34a of the jig 34 after the assembly process. At this time, by inserting the positioning pins 34a1 of the base 34a into the positioning holes 51a of the rear bottom plate 51 of the frame 31 and the positioning holes 57b of the front lower stay 57, the position of the frame 31 with respect to the base 34a is adjusted. be decided.

As shown in FIG. 31, when joining the frame 31, the front support portion 34b is slid in the direction of arrow K1 and the rear support portion 34c is slid in the direction of arrow K3 by a worker performing the joining step. . A pressing device (not shown) presses the frame 31 in a direction perpendicular to the sliding direction of the front support portion 34b and the rear support portion 34c. As a result, the sheet metals forming the frame 31 are pressed against each other, unnecessary gaps between the sheet metals are eliminated, and positioning is completed.

After that, each sheet metal forming the frame 31 is joined by fiber laser welding by an operator. When the joining of the frame 31 is completed, the operator slides the front support portion 34b in the direction of arrow K2, slides the rear support portion 34c in the direction of arrow K4, and removes the frame 31 from the jig . This completes the frame 31 .

31... Frame 56... Left strut (second support)
56d... Insertion part 56d1... Engagement part 56d3... Fitting part 56e... Insertion part (another insertion part)
60... Upper left stay (first support)
60a... Through hole (first through hole)
60b... Through hole (second through hole)
60c... Through hole (third through hole)
A... Image forming apparatus

Claims (4)

a first support made of sheet metal and having a first portion formed with a first through hole and a second through hole penetrating in the plate thickness direction;
A second support formed of sheet metal and assembled to the first support, wherein the insertion portion is bent from a second portion extending parallel to the first portion and inserted into the first through hole. a second support having
with
The insertion part has an engaging part that is inserted into and engages with the second through hole from a direction opposite to the direction of insertion into the first through hole in a state of being inserted into the first through hole,
In a state in which the insertion portion is inserted into the first through hole and the engaging portion is engaged with the second through hole, the first portion is supported by the second portion and the insertion portion. It is sandwiched from the thickness direction of the body,
The second through hole is formed above the first through hole in the vertical direction,
A frame of an image forming apparatus characterized by: The insertion portion has a fitting portion that fits into the fitted portion of the first through hole and determines the position of the first support relative to the second support in a planar direction perpendicular to the plate thickness direction. 2. The frame of the image forming apparatus according to claim 1, wherein: the first support includes a third through hole penetrating in the plate thickness direction of the first support at a position different from the first through hole and the second through hole in the first portion,
The second support is bent from a position different from the insertion portion in the second portion, and is provided with another insertion portion that is inserted into and engages with the third through hole. Item 3. The frame of the image forming apparatus according to Item 1 or 2 . The other insertion portion fits into another fitting portion of the third through hole, and determines the position of the first support relative to the second support in a plane direction perpendicular to the plate thickness direction. 4. The frame of the image forming apparatus according to claim 3 , wherein the frame has a fitting portion of .

Images