Sheet metal structure and assembly method of sheet metal structure

Abstract

To provide a sheet metal structure and an assembly method of the sheet metal structure with which positional accuracy and rigidity are improved and which do not require reinforcement members or adjustment members.SOLUTION: A sheet metal structure includes: a pair of first sheet metal members, a second sheet metal member, and a positioning mechanism. The second sheet metal member includes a flat body part, and a pair of bent parts formed by bending both end edges of the body part almost vertically. The positioning mechanism includes: a throttle part protruding inward from an inside surface of the first sheet metal member; an opening which extends from the bent parts to the body part, and is overlapping with the throttle part; and a regulating part which is formed at an end edge on a body part side of the opening and which abuts on the throttle part. A distance from the bent part to the regulating part is smaller than a protrusion height of the throttle part, and the bent part deflects and is deformed in a direction of approaching the first sheet metal member and contacts the first sheet member, in a state that the throttle part and the regulating member abut on each other, and at a fixed position separated by a prescribed distance from the regulating part, the first metal member and the bent part are fixed.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a sheet metal structure in which a plurality of sheet metal members are mechanically joined, and a method for assembling the sheet metal structure. [Background technology]

[0002] In a conventional image forming apparatus, various parts and devices are assembled in a frame structure made of sheet metal. In order to improve the mounting accuracy of the parts and devices, a frame structure including opposing side frames and a connecting frame that bridges the side frames is known.

[0003] For example, Patent Document 1 discloses a frame for an image forming device, in which devices or components are attached to opposing side panels, and which is equipped with connecting members that are spanned between the side panels and have both end faces supported by the side panels to connect the side panels.

[0004] In a configuration such as that in Patent Document 1, in which the position between the left and right side plates is determined by the bent part of the connecting member, variations in the angle tolerance of the bent part must be allowed and the side plates also need to be flat, which reduces the positional accuracy between the side plates.

[0005] Patent document 2 discloses a frame for an image forming device which is a sheet metal frame having support stays and left and right side plates which are fixed to each other, in which the support stays have protruding portions which abut perpendicularly against the left and right side plates to determine the positions of the left and right side plates relative to the support stays, bent portions which are bent to fit along the left and right side plates, and fixed portions which are provided at the bent portions and fixed to the left and right side plates. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2008-28988 A [Patent Document 2] JP 2015-163959 A Summary of the Invention [Problem to be solved by the invention]

[0007] In the configuration of Patent Document 2, the protruding portion that protrudes toward the side plate from the bent portion hits the side plate, and then the side plate bends and is fixed to the fixed portion. Therefore, even if there is variation in the angle of the bent portion, the accuracy of the distance between the left and right side plates can be improved.

[0008] However, in the configuration of Patent Document 2, the protruding portion abuts against the flat portion of the side plate, so if the side plate is thin, the protruding portion may be pressed against the side plate by the pressure applied when fixing the side plate and the fixed portion, which may cause deformation of the entire frame. As a result, there are problems such as a decrease in rigidity of the connection portion between the support stay and the side plate, and a need to adjust the position using an adjustment member when mounting an optical unit, etc.

[0009] In view of the above problems, an object of the present invention is to provide a sheet metal structure and a method for assembling the sheet metal structure, which can improve positional accuracy and rigidity and does not require reinforcing members or adjustment members. [Means for solving the problem]

[0010] In order to achieve the above object, a first configuration of the present invention is a sheet metal structure having a pair of first sheet metal members and a second sheet metal member arranged opposite each other, and a positioning mechanism. The second sheet metal member has a flat body portion and a pair of bent portions formed by bending both end edges of the body portion approximately vertically and overlapping and fixed to the first sheet metal members, and is connected to the pair of first sheet metal members in a bridging manner. The positioning mechanism positions the first sheet metal member and the second sheet metal member in a direction perpendicular to the first sheet metal member. The positioning mechanism has a drawn portion protruding inward from the inner surface of the first sheet metal member, an opening portion extending from the bent portion to the body portion and overlapping with the drawn portion, and a restricting portion formed on the end edge of the opening portion on the body portion side and abutting the drawn portion. The distance from the bent portion to the regulating portion is smaller than the protruding height of the constriction portion, and when the constriction portion and the regulating portion abut, the bent portion flexes and deforms in a direction approaching the first sheet metal member and comes into contact with the first plate member, and the first plate member and the bent portion are fixed at a fixed position a predetermined distance away from the regulating portion. Effect of the Invention

[0011] According to the first configuration of the present invention, by abutting the restricting portion formed on the bent portion against the drawn portion of the first sheet metal member, the first sheet metal member is less likely to deform than in a configuration in which the restricting portion abuts against a flat portion of the first sheet metal member. Therefore, the rigidity of the connecting portion between the first sheet metal member and the second sheet metal member can be ensured, and there is no need to install a reinforcing member at the connecting portion. In addition, because a gap is formed between the first sheet metal member and the bent portion, the angle tolerance (variation) of the bent portion can be absorbed, and the first sheet metal member and the second sheet metal member can be positioned with high precision. [Brief description of the drawings]

[0012] [Figure 1] 1 is a schematic cross-sectional view of an image forming apparatus 100 including a main body frame 101 according to an embodiment of the present invention. [Diagram 2] A perspective view of the main body frame 101 [Diagram 3] A side view of the positioning mechanism 120 of the side frame 102 and the first connecting frame 103 from the inside of the side frame 102. [Figure 4]A plan view of the positioning mechanism 120 and its surroundings seen from above. [Diagram 5] 1 is a side view of the positioning mechanism 120 and its surroundings viewed from the second connecting frame 104 side. [Figure 6] Vertical cross-sectional view of the positioning mechanism 120 [Figure 7] Horizontal cross-sectional view of the positioning mechanism 120 [Figure 8] FIG. 11 is a side view of the positioning mechanism 120 and its periphery as viewed from the second connecting frame 104 side, illustrating how the side frame 102 and the bending portion 110 are fixed together. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a schematic diagram showing a configuration of an image forming apparatus 100 including a main body frame 101 according to an embodiment of the present invention.

[0014] The image forming apparatus 100 shown in Fig. 1 is a so-called tandem type color printer, and has the following configuration: Within the main body of the image forming apparatus 100, four image forming sections Pa, Pb, Pc, and Pd are arranged in this order from the upstream side in the transport direction (the left side in Fig. 1). These image forming sections Pa to Pd are provided corresponding to images of four different colors (yellow, cyan, magenta, and black), and sequentially form images of yellow, cyan, magenta, and black through the processes of charging, exposing, developing, and transferring, respectively.

[0015] These image forming stations Pa to Pd are provided with photoconductor drums 1a, 1b, 1c, and 1d that carry visible images (toner images) of each color. Furthermore, an intermediate transfer belt 8 that rotates counterclockwise in Fig. 1 is provided adjacent to each image forming station Pa to Pd. The toner images formed on these photoconductor drums 1a to 1d are transferred sequentially onto the intermediate transfer belt 8 that moves while contacting each of the photoconductor drums 1a to 1d, and then transferred all at once by a secondary transfer roller 9 onto paper S, which is an example of a recording medium.

[0016] The paper S onto which the toner image is transferred is stored in a paper cassette 16 at the bottom of the main body of the image forming apparatus 100, and is transported to the secondary transfer roller 9 via a paper feed roller 12a and a pair of registration rollers 12b.

[0017] Next, an image forming procedure in the image forming apparatus 100 will be described. When a user inputs a command to start image formation, first, the photoconductor drums 1a-1d start to rotate by a main motor (not shown), and the surfaces of the photoconductor drums 1a-1d are uniformly charged by the charging devices 2a-2d. Next, the surfaces of the photoconductor drums 1a-1d are irradiated with a beam of light (laser light) emitted from an exposure device 5, and an electrostatic latent image corresponding to an image signal is formed on each of the photoconductor drums 1a-1d.

[0018] The developing devices 3a-3d are filled with a predetermined amount of two-component developer containing toner of each color, yellow, cyan, magenta, and black. The developing devices 3a-3d supply the toner in the developer onto the photoconductor drums 1a-1d, and the toner electrostatically adheres to the photoconductor drums 1a-1d to develop the electrostatic latent image into a toner image. When the ratio of toner in the two-component developer filled in each developing device 3a-3d falls below a specified value, toner is replenished from the toner containers 4a-4d to each developing device 3a-3d.

[0019] Then, an electric field is applied between the primary transfer rollers 6a-6d and the photoconductor drums 1a-1d by the primary transfer rollers 6a-6d at a predetermined transfer voltage, and the yellow, cyan, magenta, and black toner images on the photoconductor drums 1a-1d are primarily transferred onto the intermediate transfer belt 8. These four color images are formed with a predetermined positional relationship for forming a predetermined full-color image. Thereafter, in preparation for the subsequent formation of a new electrostatic latent image, the toner remaining on the surfaces of the photoconductor drums 1a-1d is removed by the cleaning devices 7a-7d.

[0020] When the intermediate transfer belt 8 starts to rotate counterclockwise with the rotation of the drive roller 10 by a belt drive motor (not shown), the paper S is transported from the registration roller pair 12b to a secondary transfer roller 9 provided adjacent to the intermediate transfer belt 8 at a predetermined timing, and a full-color image is transferred onto the paper S. The paper S onto which the toner image has been transferred is transported to a fixing unit 13. The toner remaining on the surface of the intermediate transfer belt 8 is removed by a belt cleaning unit 19.

[0021] The paper S conveyed to the fixing section 13 is heated and pressurized by the fixing roller pair 13a, so that the toner image is fixed to the surface of the paper S, and a predetermined full-color image is formed. The paper S on which the full-color image has been formed is then directed to a different conveying direction by the branching section 14, which branches into multiple directions, and is discharged directly (or after being sent to the double-sided conveying path 18 and printed on both sides) onto the discharge tray 17 by the discharge roller pair 15.

[0022] 2 is a perspective view of a main body frame 101 constituting the image forming apparatus 100. The main body frame 101 has a pair of side frames 102, a first connecting frame 103, a second connecting frame 104, and a third connecting frame 105.

[0023] The side frames 102 are sheet metal members (first sheet metal members) disposed facing the front side (the front side of the page in FIG. 1) and the rear side (the rear side of the page in FIG. 1) of the image forming apparatus 100. The first connecting frame 103, the second connecting frame 104, and the third connecting frame 105 are sheet metal members (second sheet metal members) respectively connected between a pair of the side frames 102 in a bridging manner.

[0024] The first connecting frame 103 to the third connecting frame 105 each have a flat body portion 109 and a pair of bent portions 110 formed by bending both longitudinal ends of the body portion 109 approximately vertically. Fig. 2 shows only the bent portions 110 on one end side (the left side in Fig. 2) of the first connecting frame 103 and the second connecting frame 104. The bent portion 110 of the third connecting frame 105 is formed by bending it downward, and is therefore not shown in Fig. 2.

[0025] By fixing the bent portions 110 of the first connecting frame 103 to the third connecting frame 105 to the inner surfaces of a pair of side frames 102, the first connecting frame 103 to the third connecting frame 105 are connected in a bridging manner between the pair of side frames 102.

[0026] A positioning mechanism 120 is provided at the connection portion between the side frame 102 and the first connecting frame 103 to the third connecting frame 105. The positioning mechanism 120 positions the first connecting frame 103 to the third connecting frame 105 in the longitudinal direction (direction perpendicular to the side frame 102).

[0027] The positioning of the first connecting frame 103 to the third connecting frame 105 relative to the surface direction of the side frame 102 is performed by fitting a positioning protrusion formed on the side frame 102 into a positioning hole formed in the bending portion 110 (none of which are shown).

[0028] Next, a detailed configuration of the positioning mechanism 120 will be described. In the following description, the positioning mechanism 120 on one end side (left side in FIG. 2) of the side frame 102 and the first connecting frame 103 will be described, but the positioning mechanism 120 on the other end side (left side in FIG. 2) of the side frame 102 and the first connecting frame 103, and the positioning mechanism 120 on the side frame 102 and the second connecting frame 104 and the third connecting frame 105 have exactly the same configuration.

[0029] FIG. 3 is a side view of the positioning mechanism 120 and the first connecting frame 103 (within the dashed circle in FIG. 2) as viewed from inside the side frame 102. FIG. 4 is a plan view of the positioning mechanism 120 and its periphery as viewed from above. FIG. 5 is a side view of the positioning mechanism 120 and its periphery as viewed from the second connecting frame 104 side (lower left direction in FIG. 2). FIG. 6 and FIG. 7 are a vertical cross-sectional view (cross-sectional view taken along the line AA in FIG. 3) and a horizontal cross-sectional view (cross-sectional view taken along the line BB in FIG. 5), respectively, of the positioning mechanism 120. Note that FIG. 3 to FIG. 7 show a state in which the side frame 102 and the first connecting frame 103 are positioned, and the side frame 102 and the first connecting frame 103 are not fixed to each other.

[0030] 3 to 7, the positioning mechanism 120 has a drawn portion 121, an opening 122, and a restricting portion 123. The drawn portion 121 has a trapezoidal shape in a side view and protrudes inward from the inner surface of the side frame 102. The drawn portion 121 is formed by drawing the side frame 102.

[0031] The opening 122 extends from the main body 109 of the first connecting frame 103, passing the bent portion 110a, to the folded portion 110. The opening 122 is disposed so as to overlap the narrowed portion 121. The opening 122 has a first region 122a formed in the main body 109 and a second region 122b formed in the folded portion 110. The restricting portion 123 is formed on the edge of the opening 122 on the main body 109 side (first region 122a).

[0032] 3, the opening width w1 of the opening 122 is larger than the width w2 of the narrowed portion 121. Therefore, when the opening 122 is disposed so as to overlap the narrowed portion 121, the peripheral portion of the opening 122 (second region 122b) does not contact the narrowed portion 121.

[0033] As shown in Fig. 7, a depth h1 of the first region 122a of the opening 122 (the distance from the bent portion 110 to the restricting portion 123) is smaller than a height h2 of the narrowed portion 121. Therefore, when the opening 122 is disposed so as to overlap with the narrowed portion 121, the restricting portion 123 abuts against the narrowed portion 121. Furthermore, as shown in Figs. 4 to 7, a gap d corresponding to the difference h2-h1 between h2 and h1 is formed between the side frame 102 and the bent portion 110.

[0034] Fig. 8 is a side view showing how the side frame 102 and the bending portion 110 are fixed. As shown in Fig. 8, when the side frame 102 and the bending portion 110 are fixed at a fixing position P above the positioning mechanism 120, the bending portion 110 bends toward the side frame 102, thereby eliminating the gap d, and the side frame 102 and the bending portion 110 come into surface contact.

[0035] The fixing method at the fixing position P is not particularly limited, and a conventionally known method such as screw fixing, spot welding, crimping, etc. is used. As the crimping method, the Tox (registered trademark) crimping method is preferred, in which two metal plates are sandwiched between convex and concave dies and compressed, and the metal plate on the convex side protrudes outward along a groove provided on the circumference of the bottom surface of the concave die, thereby fixing the two metal plates.

[0036] In this embodiment, a narrowed portion 121 is provided on the side frame 102, and a restricting portion 123 of an opening 122 abuts against the narrowed portion 122, thereby positioning the first connecting frame 103 in the longitudinal direction (direction perpendicular to the side frame 102).

[0037] As a result, when the restricting portion 123 is pressed against the side frame 102 by the pressure when fixing the side frame 102 and the bent portion 110, the side frame 102 is less likely to deform than in a configuration in which the restricting portion 123 abuts on a flat portion of the side frame 102. Therefore, the rigidity of the connecting portion between the side frame 102 and the first connecting frame 103 can be ensured, and there is no need to install a reinforcing member at the connecting portion. In addition, there is no need to perform position adjustment work using an adjustment member when mounting the exposure device 5, intermediate transfer unit, etc.

[0038] In addition, because a gap d is formed between the side frame 102 and the bent portion 110, it is possible to absorb the angle tolerance (variation) of the bent portion 110 and accurately position the side frame 102 and the first connecting frame 103. The gap d between the side frame 102 and the bent portion 110 is appropriately set according to the dimension of the bent portion 110 and the protrusion amount of the narrowed portion 121.

[0039] Furthermore, if the distance between the narrowed portion 121 and the fixing position P is short, the bending amount of the bending portion 110 increases when the bending portion 110 is fixed to the side plate frame 102, so it is necessary to increase the pressing force of the bending portion 110 against the side frame 102. As a result, there is a risk that the work efficiency will decrease and the side frame 102 will be deformed.

[0040] Therefore, in this embodiment, the fixing position P is shifted from the narrowing portion 121 so that the narrowing portion 121 and the fixing position P are separated from each other by a predetermined distance or more. Specifically, as shown in Fig. 7, it is preferable that the distance x between the narrowing portion 121 and the fixing position P closest to the narrowing portion 121 is separated by a certain distance or more. The distance x is set appropriately depending on the dimension of the bending portion 110 and the gap d between the side frame 102 and the bending portion 110.

[0041] In addition, the present invention is not limited to the above-mentioned embodiment, and various modifications are possible without departing from the spirit of the present invention. For example, in the above-mentioned embodiment, the positioning mechanism 120 between the side frame 102 and the first connecting frame 103 to the third connecting frame 105 constituting the main body frame 101 of the image forming apparatus 100 is described, but it is needless to say that the same can be applied to the frames of electronic devices other than the image forming apparatus. [Explanation of symbols]

[0042] 100 Image forming device 101 Main body frame (sheet metal structure) 102 Side frame (first sheet metal member) 103 First connecting frame (second sheet metal member) 104 Second connecting frame (second sheet metal member) 105 Third connecting frame (second sheet metal member) 109 Main body 110 Bend section 120 Positioning mechanism 121 Squeezing section 122 Opening 123 Regulatory Department P fixed position

Claims

1. A pair of first sheet metal members arranged opposite each other; A flat body portion, A pair of bent portions formed by bending both end edges of the main body portion substantially perpendicularly and overlapping and fixed to the first sheet metal member; a second sheet metal member connected to the pair of first sheet metal members in a bridging manner; a positioning mechanism that positions the first sheet metal member and the second sheet metal member in a direction perpendicular to the first sheet metal member; A sheet metal structure having The positioning mechanism includes: a drawn portion protruding inward from an inner surface of the first sheet metal member; an opening portion extending from the bent portion to the main body portion and overlapping the narrowing portion; a restricting portion formed on an edge of the opening on the side of the main body portion and in contact with the narrowing portion; having A sheet metal structure characterized in that the distance from the bent portion to the regulating portion is smaller than the protruding height of the constriction portion, and when the constriction portion and the regulating portion are in contact, the bent portion flexes and deforms in a direction approaching the first sheet metal member and contacts the first sheet metal member, and the first plate member and the bent portion are fixed at a fixed position a predetermined distance away from the regulating portion.

2. The sheet metal structure according to claim 1 , wherein the first plate member and the bent portion are fixed at the fixing position by any one of a screw fixing, a welding process, and a crimping process.

3. The first sheet metal member includes a pair of side frames arranged opposite each other with a predetermined gap therebetween; As the second sheet metal member, one or more connecting frames are connected in a bridging manner between the pair of side frames; 2. The sheet metal structure according to claim 1, which is a main body frame of an image forming apparatus.

4. A pair of first sheet metal members arranged opposite each other; A flat body portion, A pair of bent portions formed by bending both end edges of the main body portion substantially perpendicularly and overlapping and fixed to the first sheet metal member; a second sheet metal member connected to the pair of first sheet metal members in a bridging manner; A method for assembling a sheet metal structure having the following features: The first sheet metal member has a drawn portion protruding inward from an inner surface thereof, The second sheet metal member is an opening portion extending from the bent portion to the main body portion and overlapping the narrowing portion; a restricting portion formed on an edge of the opening on the side of the main body portion and in contact with the narrowing portion; having a positioning step of positioning the second sheet metal member relative to the first sheet metal member by vertically abutting the restricting portion against the drawing portion; a fixing process in which, with the restricting portion and the narrowing portion in contact with each other, the bent portion is brought into contact with the first sheet metal member by flexibly deforming the bent portion in a direction approaching the first sheet metal member, and the first sheet metal member and the bent portion are fixed at a fixed position a predetermined distance away from the restricting portion; A method for assembling a sheet metal structure, comprising the steps of:

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