Abstract:
An image forming device having an image reading section which is supported in a cantilevered state with a space between the image reading section and a top surface of an image forming section, the image forming device including: a housing of the image forming section; and a first supporting body fixed to a side surface of the housing and supporting the image reading section, wherein the first supporting body has: a first supporting portion fixed to the side surface of the housing and supporting the image reading section; and a second supporting portion extending from the first supporting portion in a same direction as the image reading section which is supported in the cantilevered state, and a receiving portion, which fixes the second supporting portion, and is provided at the side surface of the housing.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority under 35 USC 119 from Japanese Patent Application No. 2005-037597, the disclosure of which is incorporated by reference herein. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an image forming device. 
     2. Description of the Related Art 
     There are image forming devices in which an image forming unit is disposed on the top surface of a sheet feeding unit, and an image reading unit is disposed above the image forming unit. Further, a structure in which a supporting body, which supports the image reading unit, is fixed to the rear surface of the sheet feeding unit has been proposed. 
     In such a structure, as the image forming unit and the sheet feeding unit move, the image reading unit, which is supported at the supporting body, can also move integrally. Further, in this structure, because the sheet feeding unit is positioned at the lowermost portion of the image forming device and accommodates sheets in the interior thereof, the sheet feeding unit is sufficiently heavier than the image reading unit. Accordingly, the image reading unit is, via the supporting body, in a stable state. Moreover, because the weight of the image forming unit and the sheet feeding unit is not applied to the supporting body, it suffices for the supporting body to have strength that supports only the weight of the image reading unit. Accordingly, the structure of the supporting body can be made to be simple. (Refer to, for example, Japanese Patent Application Laid-Open (JP-A) No. 2001-203840.) 
     However, when such a supporting body is fixed to a side surface of the housing of the image forming unit in order to form a simpler structure, the housing warps due to the weight of the image reading unit, and problems arise in that the quality of the image formed on the sheet at the image forming unit deteriorates, the positions of the sheet and the image formed on the sheet are offset, and the like. 
     SUMMARY OF THE INVENTION 
     The present invention was developed in order to overcome the above-described problems, and provides an image forming device in which a supporting body, which supports an image reading section, can be fixed to a side surface of a housing of an image forming section, such that the image reading section is disposed in a cantilevered state with a space between the image reading section and the top surface of the image forming section, by a more simple structure than the prior art. 
     A first aspect of the present invention is an image forming device having an image reading section which is disposed with a space between the image reading section and a top surface of an image forming section and is supported in a cantilevered state, the image forming device comprising: a housing of the image forming section; and a first supporting body fixed to a side surface of the housing and supporting the image reading section, wherein the first supporting body has: a first supporting portion fixed to the side surface of the housing and supporting the image reading section; and a second supporting portion extending from the first supporting portion in a same direction as the image reading section which is supported in the cantilevered state, and a receiving portion, which fixes the second supporting portion, is provided at the side surface of the housing. 
     In the image forming device based on the present aspect, the first supporting body, which supports the image reading section, is fixed to a side surface of the housing of the image forming section. The first supporting body has a first supporting portion, which supports the image reading section and is fixed to the side surface of the housing, and a second supporting portion, which extends from the first supporting portion in the same direction as the image reading section which is supported in the cantilevered state. Further, a receiving portion, which fixes the second supporting portion, is provided at the side surface of the housing. 
     Accordingly, at the side surface of the housing, even if force is applied to a triangular region structured by the first supporting portion and the second supporting portion, and force is applied in a direction in which the first supporting body falls over, the receiving portion receives the second supporting portion. Accordingly, even though the first supporting body, which supports the image reading section, is fixed to the side surface of the housing of the image forming section, it is difficult for the side surface of the housing to warp. 
     In this way, it is difficult for the side surface of the housing to warp even though the first supporting body, which supports the image reading section, is fixed to the side surface of the housing of the image forming section. Therefore, with an even simpler structure, the image reading section can be disposed in a cantilevered state with a space between the image reading section and the top surface of the image forming section. Due to the second supporting portion extending in a substantially horizontal direction from the first supporting portion, even if force is applied in the direction in which the first supporting body falls over, warping of the housing is suppressed and the image reading section can be supported securely. 
     In a second aspect of the present invention, the receiving portion is a frame which is fixed to the side surface of the housing and stands erect from the side surface, and the second supporting portion is fixed to the frame. 
     In the image forming device based on the present aspect, the second supporting portion is fixed to the frame which is fixed to the side surface of the housing and stands erect from the side surface. Accordingly, the frame also is integral with the first supporting body, and supports the image reading section. 
     Accordingly, at the side surface of the housing, force is applied to the region of the frame, in addition to the substantially triangular region structured by the first supporting portion and the second supporting portion. Therefore, the image reading section can be fixed even more securely, and it is even more difficult for the side surface of the housing to warp. 
     In a third aspect of the present invention, the first supporting portion of the first supporting body is shaped as a hollow tube whose axial direction is a vertical direction. 
     The first supporting portion of the first supporting body of the image forming device based on the present aspect is shaped as a hollow tube whose axial direction is the vertical direction. Accordingly, the first supporting portion can more strongly support load. 
     In a fourth aspect of the present invention, a pair of the side surfaces are provided so as to oppose one another, the first supporting bodies are fixed to the side surfaces respectively, and sizes of horizontal cross-sections of the first supporting portions, which are shaped as hollow tubes, are different at one side and another side. 
     In accordance with the present aspect, the size of the horizontal cross-section of the hollow, tube-shaped first supporting portion of the first supporting body can be selected appropriately. Space can thereby be conserved. 
     In a fifth aspect of the present invention, a pair of the side surfaces are provided so as to oppose one another, the first supporting body is fixed to one of the side surfaces, and a second supporting body, whose shape is different than a shape of the first supporting body and which supports the image reading section, is fixed to another of the side surfaces. 
     In the present aspect, because the first supporting body is fixed securely to the side surface, much of the weight of the image reading section can be supported by only the first supporting body. Therefore, the second supporting body, which is fixed to the other side surface, does not have to be fixed as securely as the first supporting body. Namely, the second supporting body may be an arbitrary shape. Accordingly, the degrees of freedom in design are further increased. 
     In a sixth aspect of the present invention, the second supporting body is shaped as a hollow tube whose axial direction is a vertical direction. 
     In the present aspect, the second supporting body is shaped as a hollow tube whose axial direction is the vertical direction. Accordingly, the second supporting body can more strongly support load. 
     In a seventh aspect of the present invention, the first supporting portion of the first supporting body is shaped as a hollow tube whose axial direction is the vertical direction, and sizes of a horizontal cross-section of the first supporting portion, which is shaped as a hollow tube, of the first supporting body, and a horizontal cross-section of the second supporting body, which is shaped as a hollow tube, are different. 
     In accordance with the present aspect, the sizes of the horizontal cross-section of the hollow, tube-shaped first supporting portion of the first supporting body and the horizontal cross-section of the hollow, tube-shaped second supporting body can be selected appropriately. Space can thereby be conserved. 
     In an eighth aspect of the present invention, among the pair of side surfaces which oppose one another, the first supporting body is fixed to the side surface which is nearer to a center of gravity of the image reading section. 
     In the present aspect, by fixing the first supporting body, which is securely fixed, to the side surface which is nearer to the center of gravity of the image reading section, the burden on the second supporting body is reduced, and the degrees of freedom in design are improved accordingly. 
     In a ninth aspect of the present invention, a driving mechanism is mounted to either one of the pair of side surfaces which oppose one another, and the first supporting body is fixed to the one side surface to which the driving mechanism is mounted. 
     In the present aspect, the driving mechanism is fixed to either one of the pair of side surfaces which oppose one another. The driving mechanism generates vibrations at the time of driving. Accordingly, by fixing the first supporting body, which is securely fixed, to the one side surface to which the driving mechanism is fixed, the burden on the second supporting body is reduced, and the degrees of freedom in design are improved even more. 
     In a tenth aspect of the present invention, an electric wire, which electrically connects the image reading section and the image forming section, is attached to either one of or to both of the first supporting body and the second supporting body. 
     In the present aspect, the electric wire, which electrically connects the image reading section and the image forming section, is attached to either one of or to both of the first supporting body and the second supporting body. Accordingly, there is no need to particularly provide space for laying of the electric wire, and space can be conserved. 
     In an eleventh aspect of the present invention, an interlocking mechanism of the image forming section is attached to either one of or to both of the first supporting body and the second supporting body. 
     In the present aspect, the interlocking mechanism of the image forming section is attached to either one of or to both of the first supporting body and the second supporting body. Accordingly, there is no need to separately provide space for attaching the interlocking mechanism. Because the interlocking mechanism is attached to the side surface of the housing, it coexists with the first supporting body and the second supporting body. Accordingly, space can be conserved. 
     The interlocking mechanism is a mechanism which effects control such that, only in a case in which a given process is in a correct state, another process operates. In other words, the interlocking mechanism is a mechanism for preventing trouble which occurs due to erroneous operation or malfunctioning of machinery. For example, the interlocking mechanism may be a mechanism which senses the open/closed state of an opening/closing cover and does not permit operation of the device if the opening/closing cover is open, because problems will arise if the device operates when the opening/closing cover is open. 
     In a twelfth aspect of the present invention, either one of or both of the second supporting body and the first supporting portion of the first supporting body is structured by a plurality of metal plates being superposed together, and the metal plates are bent and form a hollow rectangular pillar portion whose axial direction is a vertical direction. 
     In the present aspect, the metal plates of either one of or both of the second supporting body and the first supporting portion of the first supporting body, are bent and form a hollow rectangular pillar portion whose axial direction is the vertical direction. Accordingly, the second supporting body and/or the first supporting portion of the first supporting body can more strongly support load. 
     As described above, in accordance with the present invention, even though the first supporting body, which supports the image reading section, is fixed to the side surface of the housing of the image forming section, it is difficult for the side surface to warp. Therefore, by an even simpler structure, the image reading section can be disposed in a cantilevered state with a space between the image reading section and the top surface of the image forming section. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a drawing schematically showing a digital copier relating to an embodiment of the present invention. 
         FIG. 2  is a perspective view schematically showing a state in which a presser plate of an image reading section of the digital copier is open. 
         FIG. 3  is a drawing of the digital copier as seen from a front surface. 
         FIG. 4  is a drawing of the digital copier as seen from a side surface. 
         FIG. 5  is a side view of a state in which the image reading section of the digital copier is pivoted and opened. 
         FIG. 6  is a perspective view showing a frame structure of the digital copier. 
         FIG. 7  is a drawing showing the frame structure of the digital copier. 
         FIG. 8  is a drawing in which the image reading section is mounted to a first supporting pillar and a second supporting pillar. 
         FIG. 9A  is a drawing showing a state before two metal plates of the second supporting pillar are joined. 
         FIG. 9B  is a drawing showing a state after the two metal plates of the second supporting pillar have been joined. 
         FIG. 9C  is a cross-sectional view taken along section C-C of  FIG. 9B . 
         FIG. 10  is a schematic drawing showing differences in the sizes of the cross-sections of a first supporting portion of the first supporting pillar, and the second supporting pillar. 
         FIG. 11  is a drawing schematically showing a state in which, when the image reading section of the digital copier is pivoted and opened, a sheet discharge tray is opened and a toner cartridge is replaced. 
         FIG. 12A  is a drawing, as seen obliquely from the rear, showing a state in which the image reading section is mounted to the first supporting pillar and the second supporting pillar. 
         FIG. 12B  is an enlarged view of the outlined portion of  FIG. 12A . 
         FIG. 13A  is a drawing showing a state in which the image reading section is not mounted. 
         FIG. 13B  is an enlarged view of the quadrilateral portion of  FIG. 13A . 
         FIG. 14  is a drawing showing a state in which an opening/closing cover of a fixing unit is opened. 
         FIG. 15  is a side view schematically showing the frame structure of the digital copier. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in  FIGS. 1 and 3 , a digital copier  10 , which is an example of an image forming device of an embodiment of the present invention, is structured such that an image reading section  200  is disposed in a cantilevered state with a space between the image reading section  200  and a sheet discharge tray  40  which is the top surface of an image forming section  100 . The image reading section  200  reads a document, and converts it into digital image data. 
     On the basis of the digital image data read at the image reading section  200 , the image forming section  100  forms a full-color image on a recording sheet P by a known electrophotographic process by using toners of the respective colors of magenta (M), yellow (Y), cyan (C), and black (K). Further, an operation panel  11  side, which is shown in  FIG. 3  and at which a user carries out various types of operations, is the front surface side, and the opposite side is the rear side. 
     First, the image reading section  200  will be explained. 
     As shown in  FIGS. 2 and 3 , the image reading section  200  has a substantially quadrilateral configuration as seen in plan view. The two corner portions at the rear side are mounted on a first supporting pillar portion  300  and a second supporting pillar portion  302  which stand erect at the corner portions of the rear side of the image forming section  100 . 
     As shown in  FIG. 2 , a presser plate  202  at the upper portion of the image reading section  200  is rotated and opened. A document stand  208 , which is transparent and is formed from a platen glass or the like and on whose top surface a document is placed, is provided beneath the presser plate  202 . An automatic document feed device  206  is provided at the upper portion of the presser plate  202 . A reading bar  210 , which is formed by a CCD or the like and which reads the document placed on the document stand  208 , is provided beneath the document stand  208 . The reading bar  210  is long and narrow from the front surface side to the rear side. The reading bar  210  is scanned in the directions of arrow W by a scanning driving mechanism  212 , so as to read the image of the document placed on the document stand  208 . 
     As shown in  FIGS. 4 and 5 , the image reading section  200  and projecting portions  220 ,  222  are connected by hinges  224 ,  226  (see  FIG. 12A ), and the image reading section  200  can rotate to a substantially horizontal state ( FIG. 4 ) and an opened state ( FIG. 5 ). As shown in  FIG. 5 , when the entire image reading section  200  is rotated and opened, the image reading section  200  is withdrawn from above the front surface side of the image forming section  100 , and a space is formed above the front surface side of the image forming section  100 . 
     As shown in  FIG. 2 , hanging-down portions  204 ,  205 , which are each shaped as an upside-down triangle whose side end portion is the base of the triangle, are formed along the side end portions of the image reading section  200 . 
     As shown in  FIG. 4 , when the image reading section  200  is in its substantially horizontal state (closed state), a top surface  300 A of the first supporting pillar portion  300  receives a bottom surface  200 A of a corner portion of the image reading section  200 , and a side surface  300 B of the first supporting pillar portion  300  receives a side surface portion  204 B of the hanging-down portion  204 . Note that, although not illustrated, at the side surface at the opposite side as well, similarly, a top surface  302 A of the second supporting pillar portion  302  receives the bottom surface  200 A of the corner portion of the image reading section  200 , and a side surface  302 B of the second supporting pillar portion  302  receives a side surface portion  205 B of the hanging-down portion  205 . 
     Next, a summary of the structure of the image forming section  100 , and a summary of the processes of carrying out formation of a color image onto the recording sheet P, will be described. 
     As shown in  FIG. 1 , a photosensitive drum  12  is disposed rotatably at the substantial center of the image forming section  100 . A rotary-type developing device  50  is disposed at the front surface side (the right side) of the image forming section  100 . 
     The photosensitive drum  12  rotates in the direction of arrow A. After the surface of the photosensitive drum  12  is charged to a predetermined potential by a charging unit  14  which is disposed at the lower side of the photosensitive drum  12 , exposure is carried out by a laser beam L exiting from a light scanning device  16  disposed beneath the photosensitive drum, and latent images, which are based on the above-mentioned digital image data of the document read by the image reading section  200 , are formed. 
     The latent images formed on the surface of the photosensitive drum  12  are developed by developing units  52 Y,  52 M,  52 C,  52 K of the respective colors of magenta (M), yellow (Y), cyan (C), and black (K), which are disposed along the circumferential direction of the rotary-type developing device  50 , such that toner images of predetermined colors are formed. Note that the developing units  52 Y,  52 M,  52 C,  52 K have replaceable toner cartridges  54 Y,  54 M,  54 C,  54 K, respectively. 
     The toner images formed on the surface of the photosensitive drum  12  are primarily transferred onto an intermediate transfer belt  30 , which is trained over a plurality of rollers  18  and a transfer roller  35  and which rotates in the direction of arrows C. Note that the un-transferred residual toner, which was not primarily transferred and remains on the surface of the photosensitive drum  12 , is removed by a photosensitive drum cleaning device  20 . 
     The rotary-type developing device  50  rotates in the direction of arrow B around a rotation shaft K, and developing rollers  56 Y,  56 M,  56 C,  56 K of the developing units  52 Y,  52 M,  52 C,  52 K of the colors corresponding to the colors of the image to be formed, successively move to a developing position G and carry out development of the respective colors. 
     The respective processes of charging, exposure, developing, primary transfer, and photosensitive drum cleaning are repeated a predetermined number of times, in accordance with the colors of the image to be formed. In this way, toner images of the respective colors are multiple-transferred and superposed onto the intermediate transfer belt  30 , and form a full-color image. 
     On the other hand, a sheet feeding cassette  22 , in which the recording sheets P are accommodated, is disposed at the lower portion of the image forming section  100 . 
     The recording sheet P is fed-out by a sheet feeding roller  24 , and is sent to a secondary transfer position T at a predetermined time by register rollers  33 . The full-color toner image of the intermediate transfer belt  30  is secondarily transferred onto the recording sheet P all at once by a secondary transfer roller  32  and a transfer roller  35 . The un-transferred residual toner of the intermediate transfer belt  30 , which was not secondarily transferred and remains, is removed by a transfer belt cleaning device  37 . 
     The recording sheet P, onto which the full-color toner image has been transferred, is sent to a fixing unit  36  which is disposed at the upper portion of the rear side. The fixing unit  36  fixes the full-color toner image onto the recording sheet P by heat and pressure. The recording sheet P, onto which the full-color toner image has been fixed, is discharged-out onto the sheet discharge tray  40  at the top portion of the image forming section  100 . 
     When the entire image reading section  200  is rotated and withdrawn from above the front surface side of the image forming section  100  as shown in  FIG. 5 , a space is formed above the front surface side of the image forming section  100 . Then, as shown in  FIG. 11 , the sheet discharge tray  40  is rotated around a rotation shaft  42  at the rear side end portion thereof and opened, such that the toner cartridge  54  can be replaced. Note that  FIG. 11  illustrates replacement of the toner cartridge  54 Y, but the other toner cartridges  54 M,  54 C,  54 K can be replaced by rotating the rotary-type developing device  50  and moving the respective developing units  52  to the position at which replacement is possible. 
     Next, the supporting structure (frame structure) of the image reading section  200  of the digital copier  10  will be described.  FIGS. 6 ,  7 ,  8  and the like are drawings showing a state in which the various types of covers of the image forming section  100  have been removed. 
     Note that, in the following explanation, description is given of fixing by screws  99 . In the drawings corresponding to these descriptions, in order to avoid the drawings from becoming complex and difficult to view, not all of the screws  99  (and screw holes) are shown. Only several, representative screws  99  (and screw holes) are shown, and illustration of the other screws  99  is omitted. 
     As shown in  FIGS. 6 and 7 , a housing  400  of the image forming section  100  is structured by side plates  402 ,  404  which are metal plates which oppose one another, and a plurality of bridging plates  406  which span between the side plates  402 ,  404  which oppose one another. 
     A box-shaped box portion  410 , which is structured by four side portions  412  and a floor surface portion  414 , is fixed to the one side plate  402 . The floor surface portion  414  of the box portion  410  and the side plate  402  are fixed by the screws  99  so as to be superposed one on the other. Accordingly, the side portions  412  stand erect from the side plate  402 . A power source circuit board (not illustrated) is mounted within the box portion  410 . By removing a power source cover  104 , which can be removed from a housing cover  102  shown in  FIG. 4  that covers the side plate  402 , the operators of the digital copier  10  can easily replace the power source circuit board. 
     As shown in  FIGS. 6 and 7 , a driving motor  420  is fixed above the box portion  410 . A gear mechanism (not shown), which is formed by plural gears and to which driving force is transferred by the driving motor  420 , is fixed to the reverse side of the side plate  402  (at the interior of the housing  400 ). 
     A first supporting pillar  500 , which is formed by plural metal plates being bent and joined together, is fixed to the side plate  402 . The first supporting pillar  500  is structured from a first supporting portion  502  and a second supporting portion  504 , which extends in the horizontal direction (the same direction as the image reading section  20 ) from the lower portion of the first supporting portion  502 , and the first supporting pillar  500  is formed substantially in the shape of the letter L overall. 
     The first supporting portion  502  is structured by a first box portion  506  which is shaped as a hollow, rectangular column whose top portion is open, and a second box portion  508  which is provided at the lower portion of the first box portion  506  and is shaped as a hollow, rectangular column which is thinner than the first box portion  506 . The longitudinal directions (axial directions) of both the first box portion  506  and the second box portion  508  are the vertical direction. The second supporting portion  504  is plate-shaped, and extends in the horizontal direction from the lower portion of the second box portion  508 . 
     The first supporting portion  502  is fixed to the side plate  402  by screws  99 . The second supporting portion  504  is superposed on a side portion  412 A, which is the top surface of the box portion  410 , and is fixed thereto by the screws  99 . Further, the second supporting portion  504  is fixed so as to be kept clear so as to not interfere with the driving motor  420 . 
     A second supporting pillar  600  is fixed to the other side plate  404  by the screws  99 . Note that the box portion  410  and the driving motor  420  are not fixed to the side plate  404 , as they are to the one side plate  402 . Therefore, the second supporting pillar  600  extends straight to the lower portion of the side plate  404 . 
     As shown in  FIGS. 9A through 9C , the second supporting pillar  600  is shaped as a hollow, substantially rectangular pillar by a metal plate  602  and a metal plate  604 , which have been subjected to bending processing, being superposed and fixed together by the screws  99 . The upper portion of the second supporting pillar  600  is divided into two chambers  610 ,  612 . Further, as shown in  FIG. 9C , an end side portion  604 A of the one metal plate  604  is bent and, together with the other metal plate  602 , forms a rectangular pillar portion  614  which is shaped as a hollow, rectangular pillar. Note that the longitudinal directions (axial direction) of both the second supporting pillar  600  and the rectangular pillar portion  614  are the vertical direction. 
     As shown in  FIG. 10 , the horizontal cross-section of the first supporting portion  502  of the first supporting pillar  500  is larger (wider) than the horizontal cross-section of the second supporting pillar  600 . The widths thereof in the front-back direction (the top-bottom direction in  FIG. 10 ) are substantially the same, but the first supporting portion  502  is wider in the left-right direction. In the present embodiment, a width W 1  of the first supporting portion  502  of the first supporting pillar  500  is about twice a width W 2  of the second supporting pillar  600 . 
     As shown in  FIGS. 8 and 12A , the two projecting portions  220 ,  222  (see  FIG. 12A ), which project downwardly from the corner portions of the rear side of the image reading section  200 , are inserted-in from an opening  506 A at the top portion of the first supporting pillar  500  and an opening  610 A at the top portion of the second supporting pillar  600 , and are fit in the first box portion  506  and the first chamber  610 , and are fixed by the screws  99 . Accordingly, the first supporting pillar  500  and the second supporting pillar  600  support the image reading section  200  in a cantilevered state. 
     The image reading section  200  is formed to be strong in order to support the document stand  208 , the scanning driving mechanism  212 , the automatic document feed device  206  (see  FIG. 2 ), and the like which are heavy. Further, at the interior of the image reading section  200 , reinforcing members such as beams or metal plates or the like span between the two projecting portions  220 ,  222  (see  FIG. 12A ) (i.e., between the first supporting pillar  500  and the second supporting pillar  600 ). Accordingly, the image reading section  200  does not bend-over even when supported in a cantilevered state in this way by the first supporting pillar  500  and the second supporting pillar  600  at the two corner portions. 
     As shown in  FIGS. 3 and 4 , the side surface portions between the image forming section  100  and the image reading section  200  are open, except for at the hanging-down portions  204 ,  205 , the first supporting pillar portion  300 , and the second supporting pillar portion  302 . (This is portion R encircled by the dotted line in  FIGS. 3 and 4 .) Accordingly, the structure is excellent in terms of design. 
     Further, as shown in  FIGS. 2 and 3 , the aforementioned automatic document feed device  206  and scanning driving mechanism  212  which scans the reading bar  210  are both disposed at the side plate  402  side. Accordingly, as shown in  FIG. 3 , when viewed from the front surface, a center of gravity position Y 2  of the image reading section  200  is further toward the side plate  402  than a central line Y 1 . 
     As described above, the image reading section  200  rotates and opens as shown in  FIGS. 4 and 5  by the hinges  224 ,  226  (see  FIG. 12A ). 
     As shown in  FIGS. 12A and 12B , an electric wire  530 , which connects the image reading section  200  and the power source circuit board (not shown) mounted to the aforementioned box portion  410 , passes through the interior of the first supporting pillar  500 . 
     Further, as shown in  FIGS. 13A and 13B , a sensing switch  550  is mounted to the interior of the first supporting pillar  500 . The sensing switch  550  senses the opening and closing of an opening/closing cover  552  provided at the outer side of the fixing unit  36  (see  FIG. 1 ) which is disposed at the upper portion of the rear side of the image forming section  100 . 
     Concretely, as shown in  FIG. 14 , sensing is carried out by a projecting portion  554 , which is formed at the opening/closing cover  552 , turning the sensing switch  550  on and off as the opening/closing cover  552  is opened and closed. Note that the power source is off when the opening/closing cover  552  is open (the state shown in  FIG. 14 ). 
     Next, operation of the present embodiment will be described. 
     As shown schematically in  FIG. 15 , the first supporting portion  502  is fixed to the side plate  402 , and the second supporting portion  504 , which extends substantially in the horizontal direction, is fixed to the box portion  410  which is fixed to the side plate  402 . Accordingly, the box portion  410 , which is integral with the first supporting pillar  500 , also supports the image reading section  200 . (that is, the box portion  410  is also a structural part which supports the image reading section  200 .) 
     Accordingly, the image reading section  200  is supported at a wide region S, which is combination of a triangular region S 1  structured by the first supporting portion  502  and the second supporting portion  504  and a rectangular region S 2  of the box portion  410 . Therefore, even though the first supporting pillar  500  is fixed to the side plate  402 , it is difficult for warping to arise at the side plate  402 . Accordingly, even though the first supporting pillar  500  is fixed to the side plate  402 , deterioration in the quality of the image caused by the warping of the housing  400  of the image forming section  100  does not occur. 
     Further, as shown in  FIG. 2 , because the first supporting pillar  500  supports a rear side corner portion of the image reading section  200 , force of the image reading section  200  falling toward the front surface side is applied around this corner portion. However, as shown in  FIG. 15 , the side portion  412 A, which is the top surface of the box portion  410 , receives the second supporting portion  504  which extends in the horizontal direction. Accordingly, force of the first supporting pillar  500  falling toward the front surface side (toward the right side in  FIG. 15 ), i.e., the force of the image reading section  200  falling toward the front surface side, can be reliably countered. Further, even if force which downwardly pushes a front surface side end portion  200 D of the image reading section  200  is applied, the first supporting pillar  500  does not collapse easily. Moreover, as described above, it is difficult for the side plate  402  to warp. 
     Because the first supporting pillar  500  is structured so as to be securely fixed to the side plate  402  in this way, there is no need for a beam which spans between the first supporting pillar  500  and the second supporting pillar  600 . 
     The first supporting pillar  500  is securely fixed to the side plate  402 , and supports almost all of the load of the image reading section  200 . Therefore, the second supporting pillar  600  does not have to be fixed as securely as the first supporting pillar  500 . Accordingly, problems do not arise even if the second supporting pillar  600  does not have the second supporting portion  504  as does the first supporting pillar  500  as shown in  FIG. 6 . Namely, because the second supporting pillar  600  can be formed in an arbitrary shape, there are many degrees of freedom in design. 
     Both the first supporting portion  502  of the first supporting pillar  500  and the second supporting pillar  600  are hollow tubular shapes (rectangular column shapes) whose axial directions are the vertical direction. Accordingly, they can more strongly support the load of the image reading section  200 . 
     As shown in  FIG. 3 , the center of gravity position Y 2  of the image reading section  200  is offset toward the side plate  402  side. Further, as shown in  FIG. 7 , the driving motor  420  which generates vibrations is mounted to the side plate  402 . Accordingly, such load and vibrations can be handled by, as shown in  FIG. 10 , fixing the first supporting pillar  500  to the side plate  402  and making the cross-section of the first supporting portion  502  large. 
     The load and vibrations which the second supporting pillar  600  receives are less than those that the first supporting pillar  500  receives. Further, as shown in  FIG. 9C , the strength is improved by bending the end side portion  604 A of the one metal plate  604 , and forming the rectangular pillar portion  614 , which is shaped as a hollow, rectangular pillar, by the end side portion  604 A and the other metal plate  602 . Therefore, problems do not arise even if the cross-section is made to be thin. Namely, there are many degrees of freedom in design. 
     The first supporting pillar  500  and the second supporting pillar  600  are fixed by the screws  99  to the side plate  402  of the housing  400  of the image forming section  100 . The two projecting portions  220 ,  222 , which project downwardly from the corner portions of the rear side of the image reading section  200 , are inserted and fit-in through the opening  506 A at the top portion of the first supporting pillar  500  and the opening  610 A at the top portion of the second supporting pillar  600 , and are fixed by the screws  99 . Assembly is therefore easy. 
     The image reading section  200  is mounted by using the housing  400  of the image forming section  100  as it is. Accordingly, the digital copier  10  can be manufactured at a low cost. 
     In other words, it is also easy to make the image forming section  100  alone be an independently manufactured product (a printer), without mounting thereto the image reading section  200 , the first supporting pillar  500 , and the second supporting pillar  600 . The image forming section  100  can be easily expanded to the digital copier  10  by mounting the image reading section  200  to the image forming section  100  as in the present embodiment. 
     In any case, because fixing is carried out by the screws  99 , the respective structures can be easily removed (separated), which is well-suited to times of carrying out repair and maintenance. 
     Further, as shown in  FIGS. 12A and 12B , the electric wire  530  passes through the interior of the first supporting pillar  500 , and as shown in  FIGS. 13A and 13B , the sensing switch  550  is mounted at the interior of the first supporting pillar  500 . Accordingly, there is no need to separately provide space for the mounting of the sensing switch  550  and the laying of the electric wire  530 . Namely, space can be conserved. Moreover, because the electric wire  530  is not exposed, this structure is preferable from the standpoint of appearance as well. 
     Note that the present invention is not limited to the above-described embodiment. 
     For example, the present invention is not limited to the structure of the image forming section  100  of the above-described embodiment. An image forming section of another structure which utilizes a known electrophotographic method may be used. Or, an image forming section may be the one which employs an image forming method other than an electrophotographic method, e.g., a known inkjet recording method which carries out image formation by an inkjet recording head in which ink drops are expelled from nozzles. 
     Further, the second supporting pillar  600  may be structured similarly to the first supporting pillar  500 .