Apparatus structure and image forming apparatus

Abstract

To provide a device structure capable of suppressing distortion of the device structure, and an image forming apparatus.SOLUTION: The second stay 102 includes a vertical stay-side 102a and a horizontal stay-side 102a that is bent by 90 degrees from an upper end of the vertical stay-side 102a. Of two screw holes 102a and 112b2 through which a screw for fastening the horizontal stay part 102b1 of the side plate penetrates, the screw hole 102b on the side separated from the vertical stay part 112b2 is made larger than the two screw holes 102b and 112a2 through which the screw for fastening the vertical stay part 102a1 penetrates.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an apparatus structure and an image forming apparatus. [Background technology]

[0002] Conventionally, there has been known an apparatus structure that includes a pair of side plates arranged opposite each other and a stay member that is fastened to the pair of side plates with screws to connect the side plates, the stay member having a first stay portion and a second stay portion that is formed by bending relative to the first stay portion.

[0003] Patent Document 1 describes the above-mentioned device structure as a stay member in which an end of a substantially horizontal, plate-like first stay portion, which is perpendicular to the opposing directions of a pair of side plates, is bent by approximately 90 degrees in the vertical direction to form a second stay portion.It describes that by bending the end of the first stay portion to form the second stay portion, the bending rigidity of the stay member can be increased and the pair of side plates can be firmly connected. Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the first stay portion and the second stay portion are fastened to the side plates in order to connect the pair of side plates more firmly, there is a risk that distortion will occur in the device structure. [Means for solving the problem]

[0005] In order to solve the above-mentioned problems, the present invention provides an equipment structure comprising a pair of side plates arranged opposite each other, and a stay member fastened to the pair of side plates with screws to connect the side plates, the stay member having a first stay portion and a second stay portion formed by bending relative to the first stay portion, wherein the screw is passed through a first stay portion fastening screw hole provided in one of the side plate or the first stay portion and is screwed into a female threaded portion provided in the other, thereby fastening the first stay portion to the pair of side plates with the screw, the screw is passed through a second stay portion fastening screw hole provided in one of the side plate or the second stay portion and is screwed into a female threaded portion provided in the other, thereby fastening the second stay portion to the pair of side plates with the screw, and one of the first stay portion fastening screw hole and the second stay portion fastening screw hole is larger than the other screw hole. [Effects of the Invention]

[0006] According to the present invention, distortion of the device structure can be suppressed. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic diagram of a color image forming apparatus according to the present invention; [Figure 2] FIG. 2 is a perspective view of a main body frame of the image forming apparatus main body as viewed obliquely from below. [Figure 3] FIG. 3 is a perspective view of the main body frame as seen from a different angle from that of FIG. 2. [Figure 4] FIG. 1 is a diagram illustrating a problem in a conventional configuration. [Figure 5] 5A and 5B are diagrams illustrating screw holes in a side plate to which a second stay member is screwed in this embodiment. [Figure 6] 10A and 10B are diagrams illustrating modified examples of screw holes in the side plates. DETAILED DESCRIPTION OF THE INVENTION

[0008] BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention will be described below with reference to the drawings. First, an example of a color image forming apparatus to which the present invention is applied will be described with reference to FIG. FIG. 1 is a schematic diagram of a color image forming apparatus according to the present invention. 1, the image forming apparatus 1 of this embodiment is a full-color image forming apparatus in which four drum-shaped photoreceptors 10Y, 10C, 10M, and 10K are arranged in tandem as latent image carriers. These photoreceptors 10Y, 10C, 10M, and 10K are configured as part of imaging units 7Y, 7C, 7M, and 7K, which serve as image forming means. These imaging units 7Y, 7C, 7M, and 7K correspond to yellow, cyan, magenta, and black, respectively, and form images in these colors.

[0009] The type of image forming apparatus 1 shown in Figure 1 has an intermediate transfer belt 14 as a surface moving member that rotates while being supported by five support rollers 15a, 15b, 15c, 15d, and 15e. Along a tension line on the lower side of this intermediate transfer belt 14, the image forming units 7Y, 7C, 7M, and 7K are arranged at intervals from the upstream side in the order of the movement direction of the intermediate transfer belt 14 as indicated by the arrow.

[0010] When forming a full-color image, toner images of each color are formed on photoconductors 10Y, 10C, 10M, and 10K provided in these imaging units 7Y, 7C, 7M, and 7K, as will be described later. Next, these different color toner images are transferred in succession onto the intermediate transfer belt 14 as it moves by primary transfer rollers 16, which function as transfer means and are arranged opposite each photoconductor with the intermediate transfer belt 14 in between. More specifically, the location on the intermediate transfer belt 14 where the primary transfer roller 16 contacts is called the transfer position, and transfer takes place at this transfer position.

[0011] The four superimposed transferred toner images are transferred onto the sheet P at the nip between the support roller 15a and the secondary transfer roller 9, and the sheet passes through a pair of fixing rollers in the fixing device 6, then passes through a conveying roller, and is discharged onto the sheet discharge tray 19 by the sheet discharge roller 26. In this way, a full-color image is obtained on the sheet.

[0012] In order to accommodate the black image single color forming mode, the intermediate transfer belt 14 is configured to be in constant contact with the photosensitive element 10K via the primary transfer roller 16. On the other hand, the intermediate transfer belt 14 is configured to contact and separate from the other photosensitive elements 10Y, 10C, and 10M by the function of a movable tension roller.

[0013] The lower part of the image forming apparatus main body is provided with a paper feed cassette 5 that stores a plurality of stacked sheets P on which an output image is to be recorded, and a paper feed unit 40 that feeds the sheets P from the paper feed cassette 5. The paper feed unit 40 includes a pickup roller 41 that is supported so as to be able to move toward and away from the sheets stacked in the paper feed cassette 5, and a separation roller pair 42 that separates the plurality of sheets fed by the pickup roller 41 and feeds only the uppermost sheet. The separation roller pair 42 is composed of a feed roller 42a and a reverse roller 42b. The feed roller 42a receives the driving force of a drive motor (described later) and is driven to rotate so that its surface moves in the sheet feeding direction at the separation nip of the separation roller pair 42. On the other hand, the reverse roller 42b receives the driving force of the drive motor via a torque limiter and is driven to rotate so that its surface moves in the direction of returning the sheet P to the paper feed cassette 5 at the separation nip.

[0014] When one sheet is sandwiched in the separation nip or when no sheet is sandwiched, the rotational load on the reverse roller 42b is relatively large. Therefore, at this time, the torque applied to the reverse roller 42b exceeds a specified value, and the torque limiter cuts off the driving force from the motor. As a result, the reverse roller 42b rotates idly relative to the torque limiter and rotates along with the feed roller 42a.

[0015] On the other hand, when multiple sheets of paper are sandwiched in the separation nip, the rotational load on the reverse roller 42b is relatively small due to slippage between the sheets. Therefore, at this time, the torque applied to the reverse roller 42b is less than a specified value, and the torque limiter transmits the driving force from the motor to the reverse roller 42b. As a result, the driving force from the motor causes the surface of the reverse roller 42b to move in the separation nip in a direction returning the sheet P to the paper feed cassette 5, and the lower sheets, excluding the top sheet, of the multiple sheets P sandwiched in the separation nip are returned to the paper feed cassette 5.

[0016] The sheet that has passed through the separation nip is conveyed toward the registration rollers 25 by the relay conveyance rollers 24 arranged in the paper feed path 43 .

[0017] Furthermore, a manual feed tray 21 for manual paper feeding is provided on the left side of the image forming main body in the drawing. Furthermore, between the writing device 4, which is a removable component and latent image writing means, and the paper feed cassette 5, there is provided a manual feed relay transport path 23, which serves as a manual transport path that transports the sheet P fed from the manual feed tray 21 by a manual feed roller 22 to a junction with the paper feed path 43. Three manual feed relay transport rollers 23a, 23b, and 23c are arranged on the manual feed relay transport path 23. The manual feed relay transport path 23 merges with the paper feed path 43 just before the relay transport roller 24.

[0018] Further, a reverse conveying path 30 is provided on the right side of the fixing device 6 of the image forming apparatus main body in the drawing to convey the sheet P again to the secondary transfer nip during double-sided printing. A reverse conveying roller 31 is arranged in the reverse conveying path 30.

[0019] The image forming apparatus 1 is also provided with an image reading device 2 equipped with a scanner unit 2b and an automatic document feeder (ADF) 2a at its top. The automatic document feeder 2a feeds out documents, which are sheets set by the user as the image reading target, and the scanner unit 2b reads the image of the documents fed out from the automatic document feeder 2a.

[0020] 1, the imaging units 7Y, 7C, 7M, and 7K only differ in the color of toner they handle, but they share the same mechanical configuration and image-forming process. Therefore, the components other than the photosensitive drums are given the same reference numerals, and the configuration and image-forming process will be described for any one imaging unit, for example, imaging unit 7Y.

[0021] Around the photosensitive member 10Y of the image-forming unit 7Y, in the clockwise rotational direction in the figure, there are arranged a charging roller 11 as a charging means for charging the photosensitive member 10Y, an irradiation position of the light beam L, a developing device 12 as a developing means, a primary transfer roller 16, a cleaning device 13, etc.

[0022] The light beam L is emitted from the writing device 4, which is equipped internally with a semiconductor laser as a light source, a coupling lens, an fθ lens, a toroidal lens, a mirror, a rotating polygon mirror, etc. The writing device 4 emits the light beam L for each color toward each photoconductor, and irradiates the light beam L onto the writing position on the photoconductor 10Y to form an electrostatic latent image.

[0023] For example, the developing device 12 of the imaging unit 7Y contains a yellow developer and visualizes the latent image in yellow. The other imaging units also contain developers of the respective colors and visualize the latent images in the colors of the developers contained therein.

[0024] During image formation, the photosensitive member 10Y rotates and is uniformly charged by the charging roller 11, and is irradiated at the writing position with a light beam L containing yellow image information to form an electrostatic latent image. This latent image is then visualized with yellow toner as it passes through the developing device 12. The yellow toner image on the photoreceptor 10Y is transferred onto the intermediate transfer belt 14 by the primary transfer roller 16. A cyan toner image is transferred onto the intermediate transfer belt 14 by the image creating unit 7C, a magenta toner image by the image creating unit 7M, and a black toner image by the image creating unit 7K, in that order, so that a full-color toner image is formed. After the transfer, the photoreceptor 10Y is cleaned of residual toner by a cleaning device 13, and then is neutralized by a neutralization lamp to prepare for the next image formation.

[0025] The sheet P is conveyed from either the paper feed cassette 5 or the manual feed tray 21 and stops once it reaches the registration rollers 25. Then, the registration rollers 25 rotate in accordance with a predetermined timing and send the sheet P toward the nip portion between the support roller 15a and the secondary transfer roller 9.

[0026] The full-color toner image superimposed on the intermediate transfer belt 14 is secondarily transferred to the sheet P at the nip between the support roller 15a and the secondary transfer roller 9. The sheet P onto which the full-color toner image has been secondarily transferred is transported toward the fixing device 6 and sandwiched in the fixing nip. The toner image on the sheet P is heated and fixed in the fixing nip by heat from the fixing roller 6a. In the case of single-sided printing, the sheet P onto which the toner image has been fixed is discharged to the outside of the machine by the paper discharge roller 26. On the other hand, in the case of double-sided printing, the sheet P is switched back, transported to the reversing conveying path 30 and reversed, and an image is formed on the side opposite to the side on which the image was previously formed, as described above, before being discharged to the outside of the machine.

[0027] A bottle holder 27 is disposed between the intermediate transfer belt 14 and the discharge tray 19 located above it. The bottle holder 27 houses toner bottles 28Y, 28M, 28C, and 28K serving as replenishment toner containers for storing Y, M, C, and K toner. The toner bottles 28Y, 28M, 28C, and 28K are placed on the bottle holder 27 with each color of toner placed on top. The Y, M, C, and K toner in the toner bottles 28Y, 28M, 28C, and 28K is appropriately replenished to the developing devices 12 of the image forming units 7Y, 7M, 7C, and 7K by toner replenishment devices, respectively. These toner bottles 28Y, 28M, 28C, and 28K are detachable from the image forming apparatus main body independently of the image forming units 7Y, 7M, 7C, and 7K.

[0028] FIG. 2 is a perspective view of a main body frame 100, which is an apparatus structural body of the image forming apparatus main body, seen obliquely from below, and FIG. 3 is a perspective view of the main body frame 100 seen from an angle different from that of FIG. 2 and 3, the main body frame 100 has a pair of side plates 110a, 110b and seven stay members 101-107 that are fastened to the pair of side plates 110a, 110b with screws 120 and connect the side plates together. The pair of side plates 110a, 110b and the stay members 101-107 are made of sheet metal and are formed into a predetermined shape by bending using press working or the like.

[0029] Rubber feet 111a, 111b, and 111c are provided as supports at the center of the bottom of the first side plate 110a (the front side in the drawing) and on both sides of the bottom of the second side plate 110b (the back side in the drawing). The main body frame 100 is supported at three points by these three rubber feet 111a, 111b, and 111c on the installation surface on which the image forming apparatus 1 is installed.

[0030] The first stay member 101 is screwed to the left end (manual feed tray 21 side) of the upper part of the pair of side plates 110a, 110b in the figure. The second stay member 102 is screwed to the left side (manual feed tray 21 side) of the pair of side plates 110a, 110b in the figure, and has a vertical stay portion 102a that is a first stay portion parallel to the vertical direction and a horizontal stay portion 102b that is a second stay portion parallel to the horizontal direction. The horizontal stay portion 102b is formed by bending the upper end of the vertical stay portion 102a by 90 degrees.

[0031] Fastening portions 102t1 and 102t2 (see FIG. 5) having two female threads are provided at both ends of the vertical stay portion 102a and the horizontal stay portion 102b in the depth direction in the drawing (the opposing direction of the pair of side plates 110a and 110b). Positioning protrusions 102c are provided at the upper and lower ends of the vertical fastening portion 102t1 of the vertical stay portion 102a. The positioning protrusions 102c engage with positioning holes provided in each of the side plates 110a and 110b, thereby positioning the second stay member 102 relative to the pair of side plates 110a and 110b. The second stay member 102 is screwed to the pair of side plates 110a and 110b by threading screws 120 into two female threaded portions provided on the fastening portions 102t1 and 102t2 of the vertical stay portion 102a and the horizontal stay portion 102b.

[0032] The third stay member 103 is disposed below the second stay member 102. The writing device 4 is positioned and supported by the third stay member 103 and a base portion 106a of the sixth stay member 106.

[0033] The fourth stay member 104 is disposed below the third stay member 103, extends from the left side of the side plate in the drawing to the right side of the side plate in the drawing, and functions as a sheet guide member that guides sheets moving through the manual feed relay conveying path 23 (see FIG. 1). The fourth stay member 104 is fastened to the side plates 110a and 110b with screws 120 at four horizontal positions.

[0034] The fifth stay member 105 is screwed to the bottom of the side plate on the right side in the drawing, and has a horizontal stay portion 105a that is parallel to the horizontal direction and an inclined stay portion 105b that is inclined relative to the vertical direction. The inclined stay portion 105b is formed by bending the right end of the horizontal stay portion 105a in the drawing, and the horizontal stay portion 105a and the inclined stay portion 105b are screwed to the side plates 110a and 110b, respectively, with screws 120.

[0035] The sixth stay member 106 is disposed above the fifth stay member 105, and as described above, includes a base portion 106a that supports the writing device 4. The sixth stay member 106 is fixed to the side plates 110a and 110b by screws 120 at two positions in the vertical direction.

[0036] The seventh stay member 107 is disposed above the sixth stay member 106 and has a vertical stay portion 107a parallel to the vertical direction and horizontal portions 107b extending horizontally from both ends of the vertical stay portion 107a in the depth direction in the drawing. The vertical stay portion 107a and each horizontal portion 107b are fastened to the side plates 110a, 110b with screws 120.

[0037] 2 and 3, parts and devices such as imaging units 7Y, 7C, 7M, and 7K, paper feed section 40, fixing device 6, bottle container 27, toner replenishing device, waste toner section, drive devices for driving photosensitive members, and electrical circuit boards are attached to main body frame 100. In recent years, in consideration of cost advantages, there has been a demand for thinning side plates 110a and 110b and stay members 101 to 107, miniaturizing the stay members, and reducing the number of stay members as much as possible.

[0038] In this embodiment, for the purpose of downsizing the device, the fourth stay member 104 is used as a sheet guide that guides sheets moving through the manual feed relay transport path 23. However, due to the positional relationship of the manual feed relay transport path 23, the fourth stay member 104 cannot be placed in a position where the fourth stay member 104 alone can provide the desired strength for the main body frame 100. Therefore, in this embodiment, stay members are placed at the four corners of the side panels (top, bottom, left, and right in the drawing) within the range permitted by the layout, thereby providing the main body frame 100 with the desired strength.

[0039] By providing the second stay member 102 with a vertical stay portion 102a and a horizontal stay portion 102b formed by bending the vertical stay portion 102a at a 90° angle, the rigidity of the second stay member 102 can be increased. The vertical stay portion 102a and the horizontal stay portion 102b of the second stay member 102 are then screwed to the side plates 110a and 110b, respectively. In this way, by increasing the rigidity of the second stay member 102 and fastening the vertical stay portion 102a and the horizontal stay portion 102b to the side plates, respectively, the strength of the left side of the main body frame 100 in FIGS. 2 and 3 can be ensured by the three members: the first stay member 101, the second stay member 102, and the fourth stay member 104.

[0040] FIG. 4 is a diagram illustrating the problems in the conventional configuration. As shown in Fig. 4, the diameter of two female screw portions 102d1 and 102d2 (see Fig. 5) provided on a vertical fastening portion 102t1 for fastening the vertical stay portion 102a of the second stay member 102 to the side plate is the same as the diameter of two female screw portions 102e1 and 102e2 provided on a horizontal fastening portion 102t2 for fastening the horizontal stay portion 102b to the side plate. In addition, in the conventional configuration shown in Fig. 4, the diameter of screw holes 112a1 and 112a2 (see Fig. 5) through which screws 120 that are screwed into the female screw portions 102d1 and 102d2 of the vertical fastening portion 102t1 of the side plates 110a and 110b pass is the same as the diameter of screw holes 112b1 and 112b2 through which screws 120 that are screwed into the female screw portions 102e1 and 102e2 of the horizontal fastening portion 102t2 pass. The diameters of the screw holes 112a1, 112a2 (see FIG. 5), 112b1, 112b2 in the side plates 110a, 110b are longer than the diameters of the female thread portions 102d1, 102d2 (see FIG. 5), 102e1, 102e2 of the second stay member 102. This prevents the shank of the screw 120, which has approximately the same diameter as the female thread portion, from coming into contact with the screw hole in the side plates 110a, 110b when the screw 120 is screwed into the female thread portion of the second stay member 102.

[0041] The perpendicularity of the horizontal stay portion 102b relative to the vertical stay portion 102a may deviate within the tolerance. Because the vertical stay portion 102a is positioned and attached to the side plates, deviation in perpendicularity affects the positional deviation of the horizontal stay portion 102b relative to the side plates. Specifically, as shown in FIG. 4(b), of the two female thread portions 102e1 and 102e2 of the horizontal fastening portion 102t2 that fastens the horizontal stay portion 102b to the side plates 110a and 110b, a portion of the female thread portion 102e2 on the side away from the vertical stay portion 102a is positioned outside the screw hole 112b2 in the side plate. As a result, when a screw 120 is threaded into the female thread portion 102e2, the shank of the screw 120 abuts against the screw hole 112b2 in the side plate 110a or 110b, and the shank of the screw 120 pushes the screw hole in the direction of arrow f in FIG. 4(b). 2 of the side plate to which the second stay member 102 is fastened is pushed in the vertical direction. Since the first side plate 110a on the near side in FIG. 2 is supported only by the rubber foot 111a located in the center in the left-right direction in FIG. 2, if the left side of the first side plate 110a in FIG. 2 is pushed in the vertical direction, the first side plate 110a will rotate, which could cause distortion in the main body frame 100.

[0042] FIG. 5 is a diagram illustrating screw holes 112a1, 112a2, 112b1, and 112b2 in the side plates to which the second stay member 102 is screwed in this embodiment. As shown in FIG. 5, in this embodiment, of the two screw holes 112b1, 112b2 in the side plate into which the screws 120 for screwing the horizontal stay portion 102b are inserted, the diameter of the screw hole 112b2 (corresponding to one of the screw holes) on the side away from the vertical stay portion 102a is made larger than the diameter of the two screw holes 112a1, 112a2 (corresponding to the other screw hole) in the side plate into which the screws 120 for screwing the vertical stay portion 102a are inserted.

[0043] 5(b), even if the perpendicularity of the horizontal stay portion 102b relative to the vertical stay portion 102a deviates within the tolerance, the female screw portion 102e2, of the two female screw portions 102e1 and 102e2 that fasten the horizontal stay portion 102b to the side plate, that is the one farther away from the vertical stay portion 102a can be positioned within the screw hole 112b2. This prevents the shank of the screw 120 from contacting the screw hole 112b2 when the screw 120 is threaded into the female screw portion 102e2. Therefore, the left side of the side plate to which the second stay member 102 is fastened in FIG. 2 from being pushed in the vertical direction, and distortion of the main body frame 100 can be prevented.

[0044] In Fig. 5, screw hole 112b2 as one of the screw holes is a round hole, but as shown in Fig. 6, it may be an elongated hole whose vertical length is longer than its horizontal length. As shown in Fig. 6, both the vertical and horizontal lengths of screw hole 112b2 are larger than the diameters of screw holes 112a1 and 112a2 into which screws 120 that fasten vertical stay portion 102a are inserted. Since deviation of female screw portion 102e2 from its original position due to deviation in squareness becomes larger in the vertical direction, making screw hole 112b2 an elongated hole that is long in the vertical direction effectively prevents female screw portion 102e2 from protruding from screw hole 112b2.

[0045] 5 and 6, of the two screw holes 112b1 and 112b2 through which the screws 120 that fasten the horizontal stay portion 102b to the side plate pass, the screw hole 112b1 on the vertical stay portion 102a side is a horizontally elongated hole, but it may also be a round hole. The diameter of the screw hole 112b1 on the vertical stay portion 102a side is preferably larger than the diameter of the screw holes 112a1 and 112a2 through which the screws 120 that fasten the vertical stay portion 102a are inserted. This prevents the female thread portion 102e1 on the vertical stay portion side of the horizontal fastening portion 102t2 from protruding from the screw hole 112b1 due to misalignment, and prevents the shank of the screw 120 from abutting against the screw hole 112b1.

[0046] In this embodiment, the diameter of the screw hole 112b2 in each side plate is larger than the diameters of the screw holes 112a1 and 112a2. However, only the screw hole 112b2 in the first side plate 110a on the front side in FIG. 2, which is supported only by the rubber foot 111a located in the center in the left-right direction in FIG. 2, may be larger in diameter than the screw holes 112a1 and 112a2. As described above, since the second side plate 110b on the back side in FIG. 2 is supported on both sides by the rubber feet 111a and 111b, even if the shank of the screw 120 is pressed substantially vertically into the screw hole in the second side plate 110b, the second side plate 110b is prevented from rotating. Therefore, when the shaft of the screw 120 is pushed into the screw hole in an approximately vertical direction, distortion of the main frame 100 can be effectively suppressed by making the diameter of only the screw hole 112b2 in the first side plate 110a on the near side in Figure 2, which is supported only by the rubber foot 111a located in the center in the left-right direction in Figure 2 and which is easy to rotate, larger than the diameter of the screw holes 112a1 and 112a2.

[0047] Incidentally, making the diameter of the screw hole 112b2 in each side plate larger than the diameters of the screw holes 112a1 and 112a2 has the following advantage over making only the screw hole 112b2 in the first side plate 110a larger than the diameter of the screw holes 112a1 and 112a2: If only the screw hole 112b2 in the first side plate 110a were larger than the diameters of the screw holes 112a1 and 112a2, when the shank of the screw 120 was pressed into the screw hole in the second side plate 110b, the reaction force from the screw hole would deform the rear side of the horizontal stay portion 102b in FIG. 2, which could cause twisting of the horizontal stay portion 102b. Making the diameter of the screw hole 112b2 in each side plate larger than the diameters of the screw holes 112a1 and 112a2 has the advantage of suppressing twisting of the horizontal stay portion 102b.

[0048] 5, in a configuration in which a positioning protrusion 102c is provided on the horizontal fastening portion 102t2 of the horizontal stay portion 102b and the horizontal stay portion 102b is positioned on the side plate, of the two screw holes 112a1, 112a2 in the side plate into which the screws 120 for fastening the vertical stay portion 102a are inserted, the diameter of the screw hole 112a2 on the side away from the horizontal stay portion 102b is made larger than the diameter of the screw holes 112b1, 112b2 (screw hole 112a2 is considered to be one of the screw holes). As a result, even if the squareness deviates within the tolerance, of the two female screw portions 102d1, 102d2 for fastening the vertical stay portion 102a to the side plate, the female screw portion 102d2 on the side away from the horizontal stay portion 102b can be positioned within the screw hole 112a2. Therefore, when the screw 120 is screwed into the female screw portion 102d2, the shank of the screw 120 can be prevented from coming into contact with the screw hole 112a2, and the shank of the screw 120 can be prevented from pushing into the side plate.

[0049] In the above description, the side plates 110a, 110b have screw holes and the stay portions 102a, 102b have female threads, but the side plates 110a, 110b may have female threads and the stay portions 102a, 102b may have screw holes through which screws pass. However, by providing screw holes in the side plates 110a, 110b and female threads in the stay portions 102a, 102b, it is possible to thread screws into the female threads from the outside, which is preferable as it improves the ease of assembly of the main body frame 100.

[0050] 2 and 3, if the angle of the inclined stay portion 105b relative to the horizontal stay portion 105a deviates from the target angle, the female thread portion fastening the horizontal stay portion 105a or the female thread portion fastening the inclined stay portion 105b of the fifth stay member 105 may protrude from the screw hole in the side plate. Therefore, it is preferable to make one of the screw holes in the side plate through which the screws 120 fastening the horizontal stay portion 105a of the fifth stay member 105 pass and the screw holes through which the screws 120 fastening the inclined stay portion 105b of the fifth stay member 105 pass larger than the other. This prevents the side plate from being pushed in by the shanks of the screws 120 that screw the fifth stay member 105.

[0051] 2 and 3, there is a risk that the female threads fastening the vertical stay portion 107a or the horizontal portion 107b of the seventh stay member 107 may protrude from the screw holes in the side plates due to misalignment of the horizontal portion 107b with respect to the vertical stay portion 107a. Therefore, either one of the screw holes in the side plates through which the screws 120 fastening the vertical stay portion 107a of the seventh stay member 107 pass or the screw holes in the side plates through which the screws 120 fastening the horizontal portion 107b of the seventh stay member 107 pass may be made larger than the other. This prevents the side plates from being pushed in by the shanks of the screws 120 that fasten the seventh stay member 107.

[0052] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to such specific embodiments, and unless otherwise specifically limited in the above description, various modifications and variations are possible within the spirit and scope of the present invention as set forth in the claims.

[0053] The above description is merely an example, and each of the following aspects provides unique effects. (Aspect 1) The device structure includes a pair of side plates 110a, 110b arranged opposite to each other, and a stay member such as a second stay member 102 that is fastened to the pair of side plates 110a, 110b with screws 120 to connect the side plates together, and the stay member has a first stay portion (in this embodiment, a vertical stay portion 102a) and a second stay portion (in this embodiment, a horizontal stay portion) formed by bending relative to the first stay portion. In this device structure, the stay member is configured such that screws 120 are passed through screw holes for fastening the first stay portion, such as screw holes 112a1, 112a2, provided in one of the side plates and the first stay portion (in this embodiment, the side plate), and screwed into female screw portions 102d1, 102d2 provided in the other (in this embodiment, the vertical stay portion 102a). The screws 120 are threaded to fasten the first stay portion to the pair of side plates with the screws 120, and the screws 120 are passed through screw holes for fastening the second stay portion, such as screw holes 112b1 and 112b2, provided in either the side plate or the second stay portion (in this embodiment, the side plate), and the screws 120 are threaded into female threaded portions 102e1 and 102e2 provided in the other (in this embodiment, the horizontal stay portion 102b), thereby fastening the second stay portion to the pair of side plates with the screws 120, and one of the screw holes for fastening the first stay portion and the screw hole for fastening the second stay portion (in this embodiment, the screw hole for fastening the second stay portion (112b2)) is made larger than the other screw hole (in this embodiment, the screw hole for fastening the first stay portion (112a1 and 112a2)). According to the first aspect, the first stay portion and the second stay portion are fastened to the pair of side plates with screws, respectively, thereby firmly connecting the pair of side plates. However, the configuration in which the first stay portion and the second stay portion are fastened to each other has the following problem. Specifically, the bending angle of the second stay portion relative to the first stay portion may deviate from the intended angle. In this case, when one of the first stay portion and the second stay portion is fastened to the side plate, the deviation in the bending angle causes a misalignment between the position of the female threaded portion for fastening the stay portion provided on one of the other stay portion and the side plate and the position of the screw hole for fastening the stay portion provided on the other stay portion. In this case, if the screw hole for fastening the second stay portion and the screw hole for fastening the first stay portion are the same size, there is a risk that a portion of the female threaded portion for fastening the stay portion may protrude from the screw hole for fastening the stay portion. When the other stay part is fastened to the side plate with a screw while part of the female screw portion for fastening the stay part protrudes from the screw hole for fastening the stay part, the shank of the screw presses into the inner surface of the screw hole for fastening the stay part, and this pushing force causes distortion in the device structure. In contrast, in aspect 1, by making one of the second stay portion fastening screw hole and the first stay portion fastening screw hole larger than the other, when the bending angle of the second stay portion relative to the first stay portion fluctuates, in a state in which a screw is passed through the other stay portion fastening screw hole to fasten the other stay portion to the side plate, it is possible to prevent a part of the female thread portion for fastening one stay portion from protruding from one of the stay portion fastening screw holes. This makes it possible to prevent the shank of the screw fastening to the side plate from abutting against the inner circumferential surface of the stay portion fastening screw hole, prevent the shank of the screw from pressing into the inner circumferential surface of the stay portion fastening screw hole, and suppress distortion of the device structure.

[0054] (Aspect 2) In the first embodiment, the pair of side plates 110a, 110b are provided with screw holes (112a1, 112a2) for fastening the first stay portion and screw holes (112b1, 112b2) for fastening the second stay portion. This makes it easier to assemble the device structure such as the main frame 100 compared to when each stay portion is provided with a screw hole for fastening the stay portion, as explained in the embodiment.

[0055] (Aspect 3) In aspect 1 or 2, a plurality of one screw holes (in this embodiment, screw holes (112b1, 112b2) for fastening the second stay portion) are provided, and of the plurality of one screw holes, at least the one screw hole (112b2) located at a position farthest from the other stay portion (in this embodiment, the vertical stay portion) that is fastened by a screw that is passed through the other screw hole is larger than the other screw holes (112a1, 112a2). As described in the embodiment, due to the deflection of the bending angle of the second stay portion, among the multiple female threaded portions (female threaded portions 112e1 and 112e2 in the embodiment) into which the screws passing through one of the screw holes (112b1 and 112b2 in the embodiment) are threaded, the female threaded portion 102e2 located farthest from the other stay portion, such as the vertical stay portion 102a, is the one that is most displaced from its original position. Therefore, the female threaded portion 102e2 located farthest from the other stay portion is likely to protrude from one of the screw holes. Therefore, by making at least one of the screw holes 112b2 located farthest from the first stay portion larger than the other screw holes 112a1 and 112a2, it is possible to effectively prevent the shank of the screw 120 fastening one of the stay portions to the side plates 110a and 110b from abutting against the inner circumferential surface of one of the screw holes. This makes it possible to prevent the shank of the screw from pushing into the inner peripheral surface of one of the screw holes, thereby suppressing distortion of the device structure.

[0056] (Aspect 4) In any of aspects 1 to 3, a stay member such as the second stay member 102 is fastened near the horizontal ends of a pair of side plates 110a, 110b so that a second stay portion such as the horizontal stay portion 102b extends horizontally from the end of a first stay portion such as the vertical stay portion 102a, one of the pair of side plates 110b has support portions such as rubber feet 111b, 111c on both sides of its bottom, and the other side plate 110a has a support portion such as rubber foot 111a in the center of its bottom, and at least the screw hole for fastening the second stay portion of the other side plate 110a is larger than the screw hole for fastening the first stay portion. According to this, as described in the embodiment, by fastening stay members such as second stay member 102 to the vicinity of the horizontal ends of the pair of side plates 110a, 110b, the pushing force of the screw shank against the inner circumferential surface of the screw hole for fastening the second stay member in the side plate due to misalignment of the bending angle of the second stay member such as horizontal stay member 102b becomes a force that rotates the side plate. One side plate 110b, which is supported on both sides by supports, is prevented from rotating due to the force that rotates the side plate, but the other side plate 110b, which is supported in the center by a support, is likely to rotate due to the force that rotates the side plate, and as a result, distortion is likely to occur in the structure of the device, such as main frame 100. Therefore, by making at least the screw hole for fastening the second stay portion in the other side plate 110a, the center of which is supported by the support portion, larger than the screw hole for fastening the first stay portion, it is possible to prevent the shank of the screw from pushing into the screw hole for fastening the second stay portion, and to prevent the above-mentioned rotational force from being generated in the other side plate. This effectively prevents distortion of the structure of the device, such as the main frame 100.

[0057] (Aspect 5) In any of aspects 1 to 4, one of the screw holes (in this embodiment, screw hole 112b2) has an elongated hole shape that is long in a direction perpendicular to the extension direction of one stay part, such as horizontal stay part 102b, from the other stay part, such as vertical stay part 102a, which is fastened by a screw 120 that passes through one of the screw holes. 6, deviation from the original position of the female thread portion 102e2 into which the screw fastening one stay portion, such as the horizontal stay portion 102b, is threaded, due to a deviation in the bending angle, becomes larger in the direction perpendicular to the extension direction of the one stay portion from the other stay portion, such as the vertical stay portion 102a. Therefore, by making one screw hole an elongated hole that is long in the direction perpendicular to the extension direction of the one stay portion from the other stay portion, it is possible to effectively prevent the one female thread portion, into which the screw fastening one stay portion is threaded, from protruding from one screw hole due to a deviation in the bending angle. This effectively prevents the shank of the screw from pushing into the inner circumferential surface of one screw hole, and effectively prevents distortion of the device structure.

[0058] (Aspect 6) In any of aspects 1 to 5, the other stay portion, such as vertical stay portion 102a, which is fastened by a screw passing through the other screw hole, is provided with a positioning portion, such as positioning protrusion 102c, which positions the side plate. According to this, the other stay part, such as vertical stay part 102a, is fastened to the side plate at a specified position by a positioning part, such as positioning protrusion 102c, so that the female thread part of one stay part becomes misaligned due to fluctuations in the bending angle. Therefore, by making one screw hole larger than the other screw hole, it is possible to prevent a part of the female thread part for fastening one stay part from protruding from one screw hole.

[0059] (Aspect 7) The image forming apparatus 1 having an apparatus structure such as the main body frame 100 includes any one of the apparatus structures according to the first to fourth embodiments. This makes it possible to prevent misalignment of the image forming members and devices supported by the device structure such as the main body frame 100, and to prevent deterioration of image quality. [Explanation of symbols]

[0060] 1: Image forming device 4: Writing device 23: Manual feed relay transport path 100: Main frame 101: First stay member 102: Second stay member 102a: Vertical stay part 102b: Horizontal stay part 102c: Positioning protrusion 102d1: Female thread 102d2: Female thread 102e1: Female thread 102e2: Female thread 102t1: Vertical fastening part 102t2:Horizontal fastening part 103: Third stay member 104: Fourth stay member 105: Fifth stay member 105a: Horizontal stay part 105b: Inclined stay part 106: Sixth stay member 106a: Base 107: Seventh stay member 107a: Vertical stay part 107b:Horizontal part 110a: First side plate 110b: Second side plate 111a: Rubber feet 111b: Rubber feet 112a1: Screw hole for fastening the vertical stay 112a2: Screw hole for fastening the vertical stay 112b1: Screw hole for fastening the horizontal stay 112b2: Screw hole for fastening the horizontal stay 120: Screw [Prior art documents] [Patent documents]

[0061] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-191793

Claims

1. A pair of side plates arranged opposite to each other; a stay member fastened to the pair of side plates by a screw to connect the side plates together, In the device structure, the stay member has a first stay portion and a second stay portion formed by bending the first stay portion, the screw is passed through a first stay portion fastening screw hole provided in one of the side plate and the first stay portion, and the screw is screwed into a female threaded portion provided in the other, thereby fastening the first stay portion to the pair of side plates with the screw; the screw is passed through a second stay portion fastening screw hole provided in one of the side plate and the second stay portion, and the screw is screwed into a female threaded portion provided in the other, thereby fastening the second stay portion to the pair of side plates with the screw; An apparatus structure characterized in that one of the screw holes for fastening the first stay portion and the screw holes for fastening the second stay portion is larger than the other screw hole.

2. 10. The device structure of claim 1, An equipment structure, characterized in that a pair of the side plates are provided with screw holes for fastening the first stay portion and screw holes for fastening the second stay portion.

3. 10. The device structure of claim 1, The one screw hole is provided in plurality, A device structure characterized in that, among the plurality of one screw holes, at least one screw hole located at a position farthest from the other stay portion fastened by a screw passing through the other screw hole is larger than the other screw hole.

4. 10. The device structure of claim 1, the stay members are fastened to the vicinity of horizontal ends of the pair of side plates so that the second stay portions extend horizontally from the ends of the first stay portions, One of the pair of side plates has support portions on both sides of the bottom portion, and the other side plate has a support portion in the center of the bottom portion; An apparatus structure, characterized in that the screw hole for fastening the second stay portion is larger than the screw hole for fastening the first stay portion.

5. 10. The device structure of claim 1, The device structure is characterized in that the one screw hole has an elongated hole shape that is long in a direction perpendicular to the extension direction of one stay part from the other stay part that is fastened by a screw that passes through the one screw hole.

6. 10. The device structure of claim 1, The device structure is characterized in that the other stay portion fastened by a screw passing through the other screw hole is provided with a positioning portion for positioning on the side plate.

7. In an image forming apparatus having an apparatus structure, 2. An image forming apparatus comprising the apparatus structure according to claim 1 as the apparatus structure.

Images