JP7192302B2 - Frame structure and image forming apparatus - Google Patents

Description

The present invention relates to a frame structure and an image forming apparatus.

2. Description of the Related Art Conventionally, as a frame structure that constitutes equipment such as an image forming apparatus, for example, those disclosed in Patent Documents 1 to 3 have already been proposed.

Patent Document 1 discloses a square pipe material comprising a U-shaped member having a U-shaped cross section and a flat reinforcing plate mechanically coupled to an opening edge of the U-shaped member. Both ends of the square pipe in the axial direction are screwed and fixed by side plates.

In Patent Document 2, two thin plate materials having a plurality of protruding portions formed on a surface portion having the widest area are opposed to each other, and the two thin plate materials are provided with a member different from the two thin plate materials. Positioning portions for coupling are provided, respectively, and the top portions of the protrusions are stacked so as to overlap each other, and the top portions of the plurality of protrusions that contact each other are butted and joined.

In Patent Document 3, a frame-shaped inner box constituent member forming at least four sides of an inner box forming a chamber is composed of a pair of inner box divided bodies having the same shape and size, and a gap is provided in the outer peripheral portion of the inner box. The constituent members of the outer box provided through the outer box are composed of a pair of outer box divided bodies having the same shape and size.

Japanese Patent No. 3375032 Japanese Patent No. 5413644 Japanese Patent Application Laid-Open No. 2011-200471

An object of the present invention is to improve safety in comparison with the case where the edges of plate materials that are combined to increase strength protrude outside the cross section along the direction intersecting the longitudinal direction.

In the invention described in claim 1, both edges are bent to form a U-shaped cross section, and the openings of the U-shaped cross section face each other and are combined so that the bent edges overlap each other. a pair of frame means forming a closed space having a rectangular cross section;
a plurality of protrusions provided on at least one of the pair of frame means and protruding to contact the inner surface of the other frame means to define the height of the closed space;
with
the bending height of both end edges of the pair of frame means is equal to or less than the protrusion height of the protrusion ;
The pair of frame means are frame structures made of sheet metal having different elongations in a tensile test .

The invention recited in claim 2 is the frame structure according to claim 1 , wherein the one frame means is made of mild steel and the other frame means is made of high strength steel.

The invention recited in claim 3 is the frame structure according to claim 2 , wherein the plurality of protrusions are provided only on the one frame means made of mild steel.

According to the invention described in claim 4 , the bent both edges of the one frame means made of the mild steel are arranged so as to be positioned inside the other frame means made of the high-strength steel. It is a frame structure described in.

The invention recited in claim 5 is the frame structure according to claim 1, wherein the pair of frame means are joined via the plurality of protrusions.

The invention recited in claim 6 is the frame structure according to claim 5 , wherein the plurality of projecting portions are arranged at four corners of the one frame means formed in an elongated plane rectangular shape. .

In the invention recited in claim 7 , the pair of frame means are joined at both ends along the longitudinal direction with cross frame means arranged in a direction crossing the pair of frame means,
said cross frame means having a joint portion arranged along the longitudinal direction of said pair of frame means at said one end;
2. The frame structure according to claim 1, wherein the plurality of projecting portions are provided at a plurality of locations along the longitudinal direction of the pair of frame means at the joint portion.

According to an eighth aspect of the present invention, one of the pair of frame means is burred to form a screw hole, and the cross frame means is screwed into the screw hole. 7 is a frame structure according to 7.

The invention recited in claim 9 comprises an apparatus main body to which the image forming means is mounted,
An image forming apparatus using the frame structure according to any one of claims 1 to 8 as a frame structure forming part of the apparatus main body.

According to the invention described in claim 1, the safety is improved compared to the case where the edges of the plate materials that are combined to increase the strength protrude outside the cross section along the direction intersecting the longitudinal direction. can be done.

According to the first aspect of the invention, the projections can be formed more easily than when the pair of frame means are not made of sheet metals having different elongations in a tensile test.

According to the invention recited in claim 2 , compared to a case in which one frame means is not made of mild steel and the other frame means is not made of high-strength steel, one frame means maintains workability while the other frame means is made of high-strength steel. The strength can be secured by the frame means of

According to the third aspect of the present invention, the plurality of protrusions can be easily formed compared to the case where only one frame means made of mild steel is not provided with the protrusions.

According to the invention recited in claim 4 , compared to the case where the bent end edges of one frame means made of mild steel are not positioned inside the other frame means made of high-strength steel, It is possible to suppress outward deformation of both edges of one of the frame means.

According to the fifth aspect of the invention, the pair of frame means can be easily joined compared to the case where the pair of frame means are joined at positions other than the plurality of projecting portions.

According to the invention recited in claim 6 , the plurality of projecting portions are arranged in the longitudinal direction of the frame means, compared to the case where they are not arranged at the four corners of one of the frame means formed in a long planar rectangular shape. The strength of the edges along the direction can be improved.

According to the seventh aspect of the invention, when the pair of frame means and the cross frame means are joined at the joint portion, the plurality of projecting portions are arranged at the joint portion along the longitudinal direction of the pair of frame means. The strength of the joint portion can be improved compared to the case where it is not provided over the portion.

According to the eighth aspect of the invention, one of the pair of frame means is subjected to burring processing to form a screw hole, and the cross frame means is not screwed into the screw hole. so that the cross frame means can be easily joined.

According to the invention recited in claim 9 , safety is improved compared to the case where the frame structure recited in any one of claims 1 to 8 is not used as the frame structure constituting part of the device body. can be made

1 is a schematic configuration diagram showing an image forming apparatus to which a frame structure according to Embodiment 1 of the present invention is applied; FIG. 1 is a perspective configuration diagram showing an apparatus main body of an image forming apparatus according to Embodiment 1 of the present invention; FIG. 1 is a cross-sectional perspective view showing a bottom frame to which a frame structure according to Embodiment 1 of the present invention is applied; FIG. 1 is a cross-sectional configuration diagram showing a bottom frame to which a frame structure according to Embodiment 1 of the present invention is applied; FIG. 1 is a cross-sectional configuration diagram showing a bottom frame to which a frame structure according to Embodiment 1 of the present invention is applied; FIG. FIG. 4 is a cross-sectional configuration diagram showing a first frame member of the bottom frame to which the frame structure according to Embodiment 1 of the present invention is applied; 1 is a plan configuration diagram showing a bottom frame to which a frame structure according to Embodiment 1 of the present invention is applied; FIG. FIG. 4 is a configuration diagram showing a method of press-molding a frame member; FIG. 4 is a configuration diagram showing a method of press-molding a frame member; FIG. 2 is a perspective configuration diagram showing a joint portion between a bottom frame and a support frame to which the frame structure according to Embodiment 1 of the present invention is applied; It is a perspective block diagram which shows a support|pillar frame. FIG. 2 is a plan configuration diagram showing a joint portion between a bottom frame and a support frame to which the frame structure according to Embodiment 1 of the present invention is applied; FIG. 2 is a cross-sectional configuration diagram showing a joint portion between a bottom frame and a support frame to which the frame structure according to Embodiment 1 of the present invention is applied; FIG. 5 is a cross-sectional configuration diagram showing part of a bottom frame to which a frame structure according to Embodiment 2 of the present invention is applied;

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

[Embodiment 1]
FIG. 1 shows an outline of the entire image forming apparatus to which the frame structure according to the first embodiment is applied. In the drawing, arrow X indicates the width direction along the horizontal direction, Y indicates the depth direction along the horizontal direction, and Z indicates the vertical direction.

<Overall Configuration of Image Forming Apparatus>
An image forming apparatus 1 according to Embodiment 1 is configured as, for example, a color printer. As shown in FIG. 1, the image forming apparatus 1 includes an apparatus main body 1a formed as a substantially rectangular parallelepiped box. The apparatus main body 1a is formed of a support structural member, an exterior cover, etc. to which the frame structure according to the first embodiment is applied. The configuration of the apparatus main body 1a will be detailed later.

The image forming apparatus 1 is configured as, for example, a color printer. This image forming apparatus 1 includes an image forming device 10 as an example of a plurality of image forming means for forming toner images developed with toner constituting a developer, and toner images formed by the image forming devices 10, respectively. An intermediate transfer device 20 that holds and conveys to a secondary transfer position T2 where it is finally secondary-transferred onto a recording paper 5 as an example of a recording medium, and a required amount of paper to be supplied to the secondary transfer position T2 of the intermediate transfer device 20. A paper feeding device 50 that accommodates and conveys the recording paper 5 and a fixing device 40 that fixes the toner image on the recording paper 5 secondary-transferred by the intermediate transfer device 20 are provided.

The image forming device 10 includes four image forming devices 10Y, 10M, 10C, and 10K that respectively form four-color toner images of yellow (Y), magenta (M), cyan (C), and black (K). It is configured. These four image forming devices 10 (Y, M, C, K) are arranged in a row while being inclined with respect to the horizontal direction X in the internal space of the device main body 1a.

As shown in FIG. 1, each imaging device 10 (Y, M, C, K) has a photosensitive drum 11 as an example of a rotating image holding means. , the following devices are mainly arranged. The main devices are a charging device 12 that charges the peripheral surface (image holding surface) of the photosensitive drum 11 on which an image can be formed (image holding surface) to a required potential, and image information ( an exposure device 13 as an example of an electrostatic latent image forming means for forming an electrostatic latent image (for each color) having a potential difference by irradiating light based on the signal), and forming the electrostatic latent image in the corresponding color (Y , M, C, K) as an example of developing means for developing toner images into toner images, and the respective toner images are transferred to the intermediate transfer device 20. A primary transfer device 15 as an example of a primary transfer means for transferring, and a drum cleaning device 16 for removing and cleaning adherents such as toner remaining on the image holding surface of the photosensitive drum 11 after the primary transfer. .

The photoreceptor drum 11 is formed by forming an image holding surface having a photoconductive layer (photosensitive layer) made of a photosensitive material on the peripheral surface of a cylindrical or columnar base material to be grounded. The photoreceptor drum 11 is supported so as to rotate in the direction indicated by the arrow A when a driving force is transmitted from a driving device (not shown).

The charging device 12 is composed of a contact-type charging roll arranged in contact with the photosensitive drum 11 . A charging voltage is supplied to the charging device 12 . As the charging voltage, when the developing device 14 performs reversal development, a voltage or current having the same polarity as the charging polarity of the toner supplied from the developing device 14 is supplied. A cleaning roll 121 that cleans the surface of the charging device 12 is arranged in contact with the back side of the charging device 12 .

The exposure device 13 irradiates the photosensitive drum 11 with light according to image information from LEDs (Light Emitting Diodes) as a plurality of light emitting elements arranged along the axial direction of the photosensitive drum 11 to form an electrostatic latent image. It consists of an LED print head or the like that forms a Information (signal) of an image input to the image forming apparatus 1 by any means is transmitted to the exposure device 13 at the time of latent image formation. Note that the exposure device 13 irradiates the circumferential surface of the photosensitive drum after being charged with a laser beam configured according to image information input to the image forming apparatus 1 to form an electrostatic latent image. may be used.

As shown in FIG. 1, each of the developing devices 14 (Y, M, C, and K) holds and exposes the developer inside a housing 140 having an opening and an accommodating chamber for the developer. A developing roll 141 that conveys the developer to a developing area facing the body drum 11 , agitating and conveying members 142 and 143 such as screw augers that convey the developer so that it passes through the developing roll 141 while agitating the developer, and a developer held by the developing roll 141 . It is constructed by arranging a layer thickness regulating member 144 for regulating the amount (layer thickness) of the agent. A developing voltage is supplied to the developing device 14 between the developing roller 141 and the photosensitive drum 11 from a power supply device (not shown). Further, the developing roll 141 and the agitating/conveying members 142 and 143 are rotated in desired directions by transmission of a driving force from a driving device (not shown). Further, as the four color developers (Y, M, C, K), a two-component developer containing non-magnetic toner and magnetic carrier is used.

The primary transfer device 15 is a contact-type transfer device having a primary transfer roll that rotates in contact with the circumferential surface of the photosensitive drum 11 via the intermediate transfer belt 21 at the primary transfer position T1 and is supplied with a voltage for primary transfer. is. As the voltage for primary transfer, a DC voltage having a polarity opposite to the charged polarity of the toner is supplied from a power supply device (not shown).

The drum cleaning device 16 includes a cleaning blade 161 disposed inside a container-shaped main body 160 for cleaning by removing deposits such as residual toner, and for recovering deposits such as toner removed by the cleaning blade 161 (not shown). It consists of a delivery member 162, such as a screw auger, which is conveyed for delivery to a collection system.

The intermediate transfer device 20 is positioned above each imaging device 10 (Y, M, C, K) as shown in FIG. The intermediate transfer device 20 is an intermediate transfer unit that circulates in the direction indicated by an arrow B while passing a primary transfer position T1 between the photosensitive drum 11 and the primary transfer device 15 (primary transfer roll). A transfer belt 21, a plurality of belt support rolls 22 to 25 that hold the intermediate transfer belt 21 in a desired state from the inner circumference and support the intermediate transfer belt 21 so as to be circulating, and the intermediate transfer belt 21 supported by the belt support rolls 25. a secondary transfer device 30 arranged on the outer peripheral surface (image holding surface) side of the intermediate transfer belt 21 to secondarily transfer the toner image on the intermediate transfer belt 21 onto the recording paper 5; It is mainly composed of a belt cleaning device 26 for cleaning the outer peripheral surface of the belt by removing toner, paper dust, and other deposits remaining on the outer peripheral surface of the belt.

As the intermediate transfer belt 21, an endless belt made of a synthetic resin such as polyimide resin or polyamide resin in which a resistance adjusting agent such as carbon black is dispersed is used. Further, the belt support roll 22 is configured as a drive roll, the belt support roll 23 is configured as a leveling roll that holds the running position of the intermediate transfer belt 21, and the belt support roll 24 is configured as a tensioning roll. 25 is configured as a backup roll for secondary transfer.

The secondary transfer device 30 includes a secondary transfer roll 31 that rotates at a secondary transfer position T<b>2 that is the outer peripheral surface portion of the intermediate transfer belt 21 supported by the belt support roll 25 in the intermediate transfer device 20 . The secondary transfer roll 31 or the belt support roll 25 of the intermediate transfer device 20 is supplied with a DC voltage having the same or opposite polarity as the charging polarity of the toner as a secondary transfer voltage.

The fixing device 40 includes a belt-shaped or roll-shaped heating rotator 41 heated by a heating means such as electromagnetic induction heating or a heat source so that the surface temperature is maintained at a predetermined temperature, and the heating rotator 41 . It is configured by arranging a roll-shaped or belt-shaped pressurizing rotator 42 that rotates in contact with the body 41 with a required pressure. In this fixing device 40, the contact portion where the heating rotator 41 and the pressurizing rotator 42 are in contact serves as a fixing processing portion N for performing required fixing processing (heating and pressing).

The sheet feeding device 50 is arranged to exist below the image forming devices 10 (Y, M, C, K). This paper feeding device 50 includes a single (or a plurality of) paper containers 52 that contain recording paper 5 of a desired size and type while being stacked on a stacking plate 51 , and the recording paper 5 is loaded from the paper container 52 . It is mainly composed of a sending device 53 for sending out one sheet at a time. The paper container 52 is attached so as to be able to be pulled out, for example, to the front side (the side facing the user during operation) of the apparatus main body 1a.

As the recording paper 5, for example, thin paper such as plain paper or tracing paper used in electrophotographic copying machines, printers, etc., or an OHP sheet made of a transparent film-like medium made of synthetic resin (such as PET). etc. In order to further improve the smoothness of the image surface after fixing, it is preferable that the surface of the recording paper 5 is as smooth as possible. A so-called thick paper having a relatively large basis weight can also be suitably used.

Between the paper feeding device 50 and the secondary transfer device 30, there are a single (or a plurality of) paper transport roll pairs 54 for transporting the recording paper 5 fed from the paper feeding device 50 to the secondary transfer position T2, and a transport guide material. A paper feed transport path 57 composed of 55 and 56 is provided. The pair of paper transport rolls 54 arranged at a position immediately before the secondary transfer position T2 in the paper feed transport path 57 is configured as rolls (registration rolls) for adjusting the transport timing of the recording paper 5, for example.

Between the secondary transfer device 30 and the fixing device 40 is provided a paper transport path 59 including a transport guide material 58 for transporting the recording paper 5 fed from the secondary transfer device 30 to the fixing device 40 . It is

On the downstream side of the fixing device 40, there is a pair of paper transport rolls 61 for discharging the recording paper 5 on which the toner image has been fixed by the fixing device 40 to the paper discharge section 60 arranged in the upper portion of the apparatus main body 1a, and a paper discharge unit. A discharge transport path 65 having a roll pair 62, transport guide members 63 and 64, and the like is provided.

In FIG. 1 , reference numeral 100 denotes a control device as an example of a control unit that controls the operation of the image forming apparatus 1 in an integrated manner. The control device 100 includes a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory) (not shown), a bus connecting these CPUs and ROMs, a communication interface, and the like.

<Basic Operation of Image Forming Apparatus>
A basic image forming operation of the image forming apparatus 1 will be described below.

Here, when the four image forming devices 10 (Y, M, C, K) are used to form a full-color image formed by combining toner images of four colors (Y, M, C, K), image forming operation will be described. It should be noted that when one or more of the four image forming devices 10 (Y, M, C, K) are used to form an image in which single-color or multiple-color toner images are combined, The image forming operation is basically the same.

When the image forming apparatus 1 receives command information requesting an image forming operation (printing), the image forming apparatus 1 is controlled by the control device 100 to operate the four image forming devices 10 (Y, M, C, K), the intermediate transfer device 20, Next, the transfer device 30, the fixing device 40, etc. are started.

In each image forming device 10 (Y, M, C, K), each photosensitive drum 11 first rotates in the direction indicated by the arrow A, and each charging device 12 moves the surface of each photosensitive drum 11 as required. It is charged with a polarity (negative polarity in the first embodiment) and a potential. Subsequently, the exposing device 13 converts the information of the image input to the image forming device 1 into each color component (Y, M, C, K) on the surface of the photoreceptor drum 11 after charging. is irradiated with light emitted based on the signal of , and an electrostatic latent image of each color component composed of a required potential difference is formed on the surface thereof.

Subsequently, each developing device 14 (Y, M, C, K) charges the electrostatic latent image of each color component formed on the photosensitive drum 11 with a corresponding color charged to a required polarity (negative polarity). (Y, M, C, K) toners are supplied and electrostatically adhered to each other for development. By this development, the electrostatic latent image of each color component formed on each photosensitive drum 11 is visualized as a four-color (Y, M, C, K) toner image developed with the corresponding color toner. become.

Subsequently, when the toner images of the respective colors formed on the photosensitive drums 11 of the imaging devices 10 (Y, M, C, K) are conveyed to the primary transfer position T1, the primary transfer device 15 transfers the toner images of the respective colors. The toner images are primarily transferred onto the intermediate transfer belt 21 rotating in the direction indicated by the arrow B of the intermediate transfer device 20 so as to be superimposed in order.

In each image forming device 10 (Y, M, C, K) after the primary transfer, the drum cleaning device 16 cleans the surface of the photosensitive drum 11 by scraping off the adhering matter. As a result, each image forming device 10 (Y, M, C, K) is ready for the next image forming operation.

Subsequently, in the intermediate transfer device 20, the primarily transferred toner image is held by the rotation of the intermediate transfer belt 21 and conveyed to the secondary transfer position T2. On the other hand, the paper feeding device 50 feeds out the required recording paper 5 to the paper feeding path 57 in accordance with the image forming operation. In the paper feed path 57, a pair of paper transport rolls 54 serving as resist rolls feeds and supplies the recording paper 5 to the secondary transfer position T2 in accordance with the transfer timing.

At the secondary transfer position T2, the secondary transfer roll 31 collectively secondary-transfers the toner images on the intermediate transfer belt 21 onto the recording paper 5 . In the intermediate transfer device 20 after the secondary transfer is completed, the belt cleaning device 26 cleans the surface of the intermediate transfer belt 21 after the secondary transfer by removing deposits such as toner remaining on the surface of the intermediate transfer belt 21 .

Subsequently, the recording paper 5 on which the toner image has been secondarily transferred is separated from the intermediate transfer belt 21 and the secondary transfer roll 31 and then transported along the paper transport path 59 to the fixing device 40 . In the fixing device 40, the recording paper 5 after the secondary transfer is introduced into the fixing processing section N between the rotating heating rotary member 41 and the pressing rotary member 42, and is caused to pass therethrough, thereby performing necessary fixing processing (heating). and pressurization) to fix the unfixed toner image on the recording paper 5 . After fixing, the recording paper 5 is discharged to the paper discharge section 60 provided in the upper portion of the apparatus main body 1a by the paper discharge roll pair 62 via the discharge transport path 65 .

Through the above operation, a full-color image formed by combining toner images made up of four color toners T (Y, M, C, K) is output.

<Configuration of device body>
As shown in FIG. 2, the apparatus main body 1a of the image forming apparatus 1 includes a support structure member 70 formed as a substantially rectangular parallelepiped frame. The support structure members 70 are arranged in a state of being erected at the four corners of the apparatus main body 1a with a front frame 71 arranged on the front surface of the apparatus main body 1a, a rear frame 72 arranged on substantially the entire rear surface of the apparatus main body 1a. a plurality of horizontal frames 77 to 81 connecting the support frames 73 to 76 along the horizontal direction Y across the front and rear of the device main body 1a; A flat plate-shaped internal frame 82 horizontally arranged to connect the front frame 71 and the rear frame 72 inside the device main body 1a connects the lower ends of the left and right support frames 73 and 74 positioned in front of the device main body 1a. It is composed of a bottom frame 83 and the like that are arranged along the horizontal direction X so as to be aligned.

The strut frames 75 and 76 arranged on the back side of the apparatus main body 1a may not be configured as independent members, but may be integrally configured by bending the rear frame 72 itself toward the back side.

These front frame 71, rear frame 72, column frames 73 to 76, horizontal frames 77 to 81, internal frame 82, bottom frame 83, etc. are welded by spot welding or fastened by fasteners such as bolts and nuts. are connected and fixed to each other.

The frame structure according to the first embodiment is employed as a frame structure forming the bottom frame 83, as shown in FIG. The bottom frame 83 is arranged horizontally with respect to the installation surface of the image forming apparatus 1, and connects the lower ends of the left and right support frames 73 and 74 as described above. The bottom frame 83 is provided with legs or the like for placing the image forming apparatus 1 on a desk or other installation location, if necessary.

As shown in FIG. 3, the bottom frame 83 is formed in the shape of an elongated plane rectangular hollow body having a required height. The bottom frame 83 has the same shape at both ends along the longitudinal direction. The bottom frame 83, as shown in FIG. 3, comprises first and second frame members 84, 85 as an example of a pair of frame means. Both edges of the first and second frame members 84 and 85 are bent to form a U-shaped cross section. As shown in FIG. 4(a), the first and second frame members 84 and 85 are combined so that the openings having a U-shaped cross section face each other and the bent edges are overlapped. A closed space 86 having a rectangular cross section is formed. The closed space 86 forms a closed space in cross sections in the width direction intersecting the longitudinal direction of the first and second frame members 84 and 85 . Both ends along the longitudinal direction of the first and second frame members 84 and 85 are open. However, both longitudinal ends of the first and second frame members 84 and 85 may of course be closed.

The first and second frame members 84, 85 are made of sheet metal having different elongations in a tensile test, for example. The first frame member 84 arranged upward along the vertical direction Z has a smaller elongation than the second frame member 85 arranged downward along the vertical direction Z. As shown in FIG. The first frame member 84 is made of mild steel, for example. Mild steel is a steel plate with a carbon content of about 0.18-0.30%. The second frame member 85 is made of high strength steel, for example. High-strength steels are steel sheets with increased tensile strength. Ordinary steel plates have a tensile strength of about 300 MPa, whereas high-strength steel has a tensile strength of about 400 to 600 MPa or more. On the other hand, mild steel is easier to press work such as bending and drawing than high-strength steel.

Further, in this embodiment, the plate thickness t1 of the first frame member 84 made of mild steel can be set thicker than the plate thickness t2 of the second frame member 85 made of high-strength steel (t1>t2). However, the first and second frame members 84 and 85 may of course have the same plate thickness.

As shown in FIG. 5(a), the first frame member 84 is formed by press-working an elongated flat rectangular mild steel sheet metal that has been cut in advance to have the same length as the bottom frame 83. , the left and right edges 841 and 842 along the width direction that intersects the longitudinal direction are bent downward by approximately 90 degrees with respect to the ceiling wall 843, and have a U-shaped cross section with an opening 844 on the lower end surface. is formed in Both edges 841 and 842 of the first frame member 84 are arranged substantially parallel to each other. Both end edges 841 and 842 of the first frame member 84 are set to have the same bending length L1 from the upper end surface of the ceiling wall 843 . Further, both end edges 841 and 842 of the first frame member 84 are formed so that the opening width W1 of the outer surface thereof has a required value.

As shown in FIGS. 4B and 6, the first frame member 84 is provided with a plurality of protrusions 845 at both longitudinal ends thereof. In the illustrated embodiment, as shown in FIG. 3, a total of eight projections 845 are provided, four at each longitudinal end. Note that FIG. 3 shows a cross section of the projecting portion 845 provided at the other end along the longitudinal direction, which is cut along the longitudinal direction at the center. Two protrusions 845 are provided. As shown in FIG. 7, the plurality of projecting portions 845 are arranged at the ends along the longitudinal direction of the first frame member 84, and are arranged near the ends along the width direction intersecting the longitudinal direction. Two pairs of protrusions 845 ₁ , 845 ₁ and 845 are separated along the longitudinal direction of the first frame member 84 by a required distance L3, each pair comprising protrusions 845 ₁ , 845 ₁ and 845 ₂ , 845 ₂ . _{2,845 2 are} arranged.

The plurality of projections 845 are integrally formed to project from the ceiling wall 843 of the first frame member 84 toward the inner surface of the second frame member 85, as shown in FIG. 4(b). . The plurality of protruding portions 845 are formed by press working or the like at the same time as the bending of the left and right edges 841 and 842 or in a separate process. Each protrusion 845 defines the height H of the closed space 86 by contacting (abutting) the inner surface of the second frame member 85 at its lower end surface. The first frame member 84 is joined to the inner surface 853a of the second frame member 85 via the lower end surfaces 845a of the plurality of projections 845 by spot welding or the like. Needless to say, the number of protrusions 845 is not limited to eight.

Each protruding portion 845 is formed in a substantially truncated cone shape, a substantially cylindrical shape, or the like, as shown in FIG. In the illustrated embodiment, each projecting portion 845 has a substantially truncated conical shape in which the diameter D1 of the upper end surface of the first frame member 84 is set larger than the diameter D2 of the lower end surface 845a of the second frame member 85 side. formed. As shown in FIG. 4(b), each projecting portion 845 has a projecting height H that projects downward from the upper end surface of the first frame member 84 at the same height. Each projecting portion 845 defines the height H of the closed space 86 by being joined to the inner surface of the second frame member 85 as described above.

On the other hand, as shown in FIG. 5(b), the second frame member 85 is press-formed into an elongated plane rectangular high-strength steel sheet that has been cut in advance to have the same length as the bottom frame 83. etc., both end edges 851 and 852 along the width direction that intersects the longitudinal direction are bent upward at approximately 90 degrees with respect to the bottom wall 853 to form a cross section having an opening 854 on the upper end surface. It is formed in a U shape. Both edges 851 and 852 of the second frame member 85 are arranged substantially parallel to each other. Both end edges 851 and 852 of the second frame member 85 are set to have the same bending length L2 from the inner surface of the second frame member 85 . Further, the opening width W2 of the inner side surfaces of the both end edges 851 and 852 of the second frame member 85 is set equal to or slightly larger than the opening width W1 of the outer side surface of the first frame member 84 . Therefore, as shown in FIG. 4(a), the first and second frame members 84, 85 have openings 844, 854 with U-shaped cross sections facing each other, and bent end edges 841, 842 and Both edges 851 and 852 of the second frame member 85 are positioned in contact with the outer sides of both edges 841 and 842 of the first frame member 84 in a state in which the two members 851 and 852 are superimposed on each other.

However, the first and second frame members 84 and 85 are configured such that both edges 851 and 852 of the second frame member 85 are located inside the edges 841 and 842 of the first frame member 84. Alternatively, both edges 851 and 852 of the second frame member 85 and both edges 841 and 842 of the first frame member 84 may alternately be positioned outward.

When the first and second frame members 84 and 85 are overlapped so that both edges 851 and 852 of the second frame member 85 are positioned outside the edges 841 and 842 of the first frame member 84, the bottom When a bending load, a pressing load, or the like acts on the frame 83, the edges 851, 852 of the second frame member 85 having high strength are positioned on the outer side, so that the edges 841, 842 of the first frame member 84 deformation is suppressed.

By the way, in the first frame member 84 according to this embodiment, the bent length L1 of the left and right end edges 841 and 842 is set to be equal to or less than the protrusion height H of the protrusion 845 . To explain further, in the first frame member 84 according to this embodiment, as shown in FIG. It is set to be shorter by a length ΔL1. As a result, when the first frame member 84 is joined to the second frame member 85, a gap of length ΔL1 is formed between the lower ends of both edges 841 and 842 and the inner surface of the second frame member 85. are formed, and the lower ends of both edges 841 and 842 do not contact the inner surface of the second frame member 85 .

In the second frame member 85, the bent length L2 of the left and right edges 851 and 852 is set to be equal to or less than the protrusion height H of the protrusion 845. As shown in FIG. To explain further, in the second frame member 85 according to this embodiment, as shown in FIG. It is set to be shorter by a length ΔL2. As a result, in the state where the second frame member 85 is joined to the first frame member 84, there is a length ΔL2 between the upper ends of both edges 851 and 852 and the upper end face of the first frame member 84. A gap is formed so that the upper ends of both edges 851 and 852 do not protrude outward (upward) from the upper end surface of the first frame member 84 .

Both edges 851 and 852 of the second frame member 85 are formed by bending (pressing) using a die 200 and a punch 201, as shown in FIG. Both end edges 851 and 852 of the second frame member 85 are inevitably bent into a curved shape having a slight curvature with respect to the bottom wall 853 during the bending process. Therefore, both end edges 851 and 852 of the second frame member 85 have a bending radius R (curvature radius R=0.5t2) at the bent corners. The bending length L1 of both edges 841 and 842 of the first frame member 84 is a value considering the bending radius R of both edges 851 and 852 of the second frame member 85 . That is, the first frame member 84 is set such that the bending length L1 of both edges 841 and 842 is shorter than the value considering the bending radius R (ΔL2=approximately 1 mm).

Further, as shown in FIG. 9, both end edges 841 and 842 of the first frame member 84 are formed by cutting (pressing) using a cutting die 202 and a punch 203 at the leading edge. Both edges 841 and 842 of the first frame member 84 inevitably have a cutting allowance that is bent inward at the edges of both edges 841 and 842 during the cutting process. Therefore, the length L1 of both edges 841 and 842 of the first frame member 84 is a value that takes into consideration the cutting margin. That is, the first frame member 84 is set shorter than the value (ΔL1=approximately 0.8 mm) in consideration of the cutting allowance of both edges 841 and 842 thereof.

As shown in FIG. 10, a bottom frame 83 made up of first and second frame members 84 and 85 has left and right strut frames 73 and 74 as an example of cross frame means at both ends along its longitudinal direction. are spliced. The left and right support frames 73 and 74 are arranged along the vertical direction Z and intersect the bottom frame 83 arranged along the horizontal direction X, as shown in FIG. Although FIG. 10 shows the joint between the bottom frame 83 and the right support frame 74, the joint between the bottom frame 83 and the left support frame 73 is constructed in the same manner.

As shown in FIG. 11, the right support frame 74 is press-worked or the like so that both edges 741 and 742 extending in the width direction, which is the direction that intersects the longitudinal direction, are bent inward to form an opening on the inner side surface. It is formed in a U-shaped cross section having a portion 743 . A side surface 744 of the right support frame 74 is provided with a concave portion 745 formed in a concave shape toward the inner surface for attaching other members.

Short joint pieces 746 and 747 are provided at the lower end of the support frame 74 and integrally formed with the end edges 741 and 742 by bending them into a substantially L-shape along the horizontal direction. Joint holes 748 and 749 for joining with the bottom frame 83 are formed in the joint pieces 746 and 747 at a required interval L4 along the horizontal direction.

As shown in FIG. 12, the interval L4 between the joint holes 748 and 749 of the support frame 74 is the length of the bottom frame 83 among the four projecting portions 845 provided at one end along the longitudinal direction of the bottom frame 83. It is set to a value that sandwiches the two projecting portions 845 ₁ and 845 ₁ arranged at the ends along the longitudinal direction along the longitudinal direction of the bottom frame 83 .

That is, the joint hole 748 opened toward the base end portion along the horizontal direction of the support frame 74 is located outside the two projecting portions 845 ₁ and 845 ₁ arranged at the ends along the longitudinal direction of the bottom frame 83 . (closer to the edge). In addition, the joint hole 749 opened toward the tip portion of the support frame 74 along the horizontal direction is formed by the two projecting portions 845 ₂ and 845 ₂ arranged inside the end portion along the longitudinal direction of the bottom frame 83 . It is located outside (closer to the edge).

On the other hand, in the bottom frame 83, as shown in FIG. Insertion holes 856 and 857 and fastening holes 846 and 847 are opened at the positions where the holes are formed.

In addition, as shown in FIG. 13, the bottom frame 83 corresponds to the joint pieces 746 and 747 of the support frame 74, and both ends of the first and second frame members 84 and 85 along the longitudinal direction are connected to each other. The lengths of the edges 841, 842 and 851, 852 are set longer than the other portions.

That is, the first frame member 84 is set such that the length L1 of both edges 841 and 842 contacts the inner surface of the second frame member 85 having the same value as the height H of the projection 845. . The second frame member 85 has a length L2 of both edges 851 and 852 that is equal to or greater than the upper end surface of the first frame member 84 that is equal to or greater than the height H of the projecting portion 845. set to a value.

Insertion holes 856 and 857 opened at both end edges 851 and 852 of the second frame member 85 are, as shown in FIG. It is. On the other hand, fastening holes 846 and 847 opened at both end edges 841 and 842 of the first frame member 84 are for fastening fasteners such as bolts 300 for joining the support frame 74 .

Screw holes are formed in the fastening holes 846 and 847 of the first frame member 84 by burring. In the burring process, both left and right edges 841 and 842 of the first frame member 84 are pressed to form cylindrical screw holes.

<Action of frame structure>
In the bottom frame 83 according to the first embodiment, as follows, compared to the case where the edges of the plate materials combined to increase strength protrude outside the cross section along the direction intersecting the longitudinal direction, It is possible to improve safety.

As shown in FIGS. 3 to 5, the bottom frame 83 includes a first frame member 84 formed into a U-shaped cross section having an opening 844 by bending both edges 841 and 842 , both edges 851 and 842 . 852 is bent to form a second frame member 85 having a U-shaped cross section with an opening 854, the openings 844, 854 of the first and second frame members 84, 85 are opposed to each other and Both edges 841, 842 and 851, 852 are combined so as to overlap each other to form a closed space 86 having a rectangular cross section. Therefore, the bottom frame 83 constitutes a frame structure having a simple structure and enhanced rigidity.

In addition, the first and second frame members 84 and 85 are joined to each other via a plurality of projections 845 provided on the first frame member 84 and defining the height H of the closed space 86. The height H of the space 86 can be defined with high accuracy. In addition, since the plurality of protrusions 845 are arranged at both longitudinal ends of the bottom frame 83, the rigidity of the longitudinal ends of the bottom frame 83 is enhanced.

Furthermore, the lengths L1, L2 of both edges 841, 842 and 851, 852 of the first and second frame members 84, 85 are set lower than the protrusion height H of the protrusion 845. As shown in FIG. Therefore, both edges 851 and 852 of the second frame member 85 do not protrude (expose) from the surface of the bottom frame 83 , and there is a risk that a user or the like who operates the image forming apparatus 1 may come into contact with the edges of the bottom frame 83 . can be avoided.

[Embodiment 2]
14A and 14B are cross-sectional configuration diagrams showing the frame structure of the image forming apparatus according to the second embodiment.

In the first embodiment, the case where the plurality of projections 845 are provided near the ends in the width direction intersecting the longitudinal direction of the longitudinal ends of the first frame member 84 has been described. , the second embodiment differs from the first embodiment in the arrangement of the plurality of protrusions 845 .

That is, in the second embodiment, as shown in FIGS. 14(a) and 14(b), the plurality of projecting portions 845 are arranged at the respective ends of the first frame member 84 along the longitudinal direction. Depending on the width of the first frame member 84, only one is arranged in the central portion along the width direction of the first frame member 84, not near both edges along the width direction of the first frame member 84. Alternatively, the first frame member 84 is configured to be arranged at the central portion and both end portions along the width direction.

In this way, by varying the arrangement of the plurality of protrusions 845 along the width direction of the first frame member 84, it is possible to deal with various frame members 84 having different dimensions along the width direction. .

Since other configurations and functions are the same as those of the first embodiment, description thereof will be omitted.

In the above embodiment, the case where the bottom frame is configured as the frame structure has been described. Good things, of course.

Further, in the above embodiment, the case where the image forming apparatus is a full-color image forming apparatus having image forming apparatuses for yellow (Y), magenta (M), cyan (C), and black (K) has been described. However, the present invention is not limited to this, and can of course be applied to a monochrome image forming apparatus as well.

REFERENCE SIGNS LIST 1 image forming apparatus 1a apparatus main bodies 10Y to 10K full-color image forming apparatus 11 photosensitive drum 70 support structure member 71 front frame 72 rear frames 73 to 76 strut frame 83 bottom frame 84 first Frame member 841 Edge 842 Edge 845 Protrusion 85 Second frame member 851 Edge 852 Edge 86 Closed space

Claims (9)

Both edges are bent to form a U-shaped cross section, and the openings of the U-shaped cross section face each other, and the bent edges are combined to overlap each other to form a closed space with a rectangular cross section. a frame means of
a plurality of protrusions provided on at least one of the pair of frame means and protruding to contact the inner surface of the other frame means to define the height of the closed space;
with
the bending height of both end edges of the pair of frame means is equal to or less than the protrusion height of the protrusion ;
A frame structure in which the pair of frame means are made of sheet metal having different elongations in a tensile test . 2. The frame structure of claim 1 , wherein said one frame means is comprised of mild steel and said other frame means is comprised of high strength steel. 3. The frame structure of claim 2 , wherein said plurality of protrusions are provided only on said one frame means made of mild steel. 3. A frame structure according to claim 2 , wherein the bent edges of said one frame means of mild steel are arranged to lie inside said other frame means of said high strength steel. 2. The frame structure according to claim 1, wherein said pair of frame means are joined via said plurality of protrusions. 6. The frame structure according to claim 5 , wherein said plurality of projecting portions are arranged at four corners of said one frame means which is formed in an elongated planar rectangular shape. The pair of frame means are joined at both ends along the longitudinal direction with cross frame means arranged in a direction crossing the pair of frame means,
said cross frame means having a joint portion arranged along the longitudinal direction of said pair of frame means at said one end;
2. The frame structure according to claim 1, wherein the plurality of projecting portions are provided at a plurality of locations along the longitudinal direction of the pair of frame means at the joint portion. 8. The frame structure according to claim 7, wherein one of said pair of frame means is burred to form a screw hole, and said cross frame means is screwed into said screw hole. comprising an apparatus main body to which an image forming means is mounted,
An image forming apparatus using the frame structure according to any one of claims 1 to 8 as a frame structure forming part of the apparatus body.

Images