Patent Publication Number: US-11656569-B2

Title: Image forming apparatus restricting trajectory of electrical box during assembly

Description:
TECHNICAL FIELD 
     The present invention relates to an image forming apparatus. 
     BACKGROUND ART 
     An electrophotographic color image forming apparatus generally has four image forming units, which correspond to images of four different colors (cyan, magenta, yellow, and black), disposed in an image forming apparatus body thereof (for example, see Patent Literature 1). 
     The four image forming units each include a processing unit (e.g., a photosensitive drum unit, a developing unit, or the like) that performs an image formation process on a sheet. The four image forming units are disposed between a front frame and a rear frame of the image forming apparatus body. On the rear frame, a high voltage board that supplies high voltage to the processing units of the image forming units, and an engine board that drives a drive motor of a conveyance system and the like are mounted on the side opposite to the image forming unit side. 
     The rear frame usually has, in addition to the high voltage board and the engine board, a control board mounted thereon that performs control of image processing and control of display. A known structure for mounting the control board is configured such that the control board is housed by an electrical box and the electrical box is arranged to overlap the high voltage board and the engine board from the outer side. 
     CITATION LIST 
     Patent Literature 
     
         
         Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2016-012066 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     The above-described arrangement in which the electrical box overlaps the high voltage board and the engine board (first electrical board) allows the area of the rear frame (frame side plate) to be reduced and the control board (second electrical board) to be arranged with high space efficiency. 
     In this case, however, when an operator assembles the electrical box to the frame side plate, his/her field of view is obstructed by the electrical box, so that the operator is unable to visually recognize the position of the already assembled first electrical board. Because of this, during assembling of the electrical box, a part of the electrical box may accidentally contact the first electrical board and such a contact may damage the first board. 
     The present invention has been achieved in view of the aforementioned circumstances, and an object of the invention is to, in an image forming apparatus in which an electrical box housing a second electrical board is arranged to overlap a first electrical board, enable the electrical box to be assembled to a predetermined position without contacting the first electrical board. 
     Solution to Problem 
     An image forming apparatus according to the present invention includes an image forming apparatus body that houses an image forming unit, a first electrical board and a second electrical board that are disposed on a side opposite to the image forming unit side on a frame side plate provided on the image forming apparatus body, and an electrical box that houses the second electrical board and is arranged to overlap the first electrical board from an outer side of the image forming apparatus body. 
     A mounting surface of the frame side plate on which the first electrical board is mounted has a frame protruding plate provided thereon that is formed perpendicularly to the mounting surface and protrudes outward of the image forming apparatus body. The electrical box has a box protruding plate that overlaps a side surface of the frame protruding plate when assembling of the electrical box to the frame side plate is completed, and an engaging portion for assembling that protrudes in a thickness direction from the box protruding plate. The electrical box is configured such that, when assembling of the electrical box to the frame side plate is carried out, with the engaging portion for assembling in engagement with a first engaged portion formed on a protruding side end of the frame protruding plate, the electrical box as a whole is turned around an axis parallel to an extending direction of the frame protruding plate with the first engaged portion as a fulcrum to thereby restrict a trajectory of the electrical box during the assembling. 
     Advantageous Effects of Invention 
     According to the present invention, in an image forming apparatus in which an electrical box housing a second electrical board is arranged to overlap a first electrical board, it is possible to assemble the electrical box to a predetermined position without the electrical box contacting the first electrical board. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a schematic overall view of an image forming apparatus in an embodiment; 
         FIG.  2    is a perspective view of the image forming apparatus with an electrical box detached from a rear frame, as viewed obliquely from the rear left side; 
         FIG.  3    is rear view of the image forming apparatus with the electrical box detached from the rear frame; 
         FIG.  4    is a rear view of the upper half of the image forming apparatus with the electrical box mounted on the rear frame; 
         FIG.  5    is a perspective view of the upper half of the image forming apparatus with the electrical box mounted on the rear frame, as viewed obliquely from the upper rear left side; 
         FIG.  6    is a perspective view of the upper half of the image forming apparatus with the electrical box mounted on the rear frame, as viewed obliquely from the lower rear left side; 
         FIG.  7    is a sectional view taken along the line VII-VII in  FIG.  4   ; 
         FIG.  8    is an enlarged view of the circled area VIII in  FIG.  5   ; 
         FIG.  9    is a perspective view of the electrical box with a lid member removed therefrom; 
         FIG.  10    is an enlarged perspective view of the vicinity of an opening formed in an upper side plate of the electrical box; 
         FIG.  11    is a perspective view of the electrical box as viewed from the lid member side; 
         FIG.  12    is a cut model taken along the line XII-XII in  FIG.  11   ; 
         FIG.  13    is a cut model taken along the line XIII-XIII in  FIG.  4   ; 
         FIG.  14    is a perspective view of the electrical box as viewed from the side facing a box protruding plate; 
         FIG.  15    is a perspective view of the state where the electrical box has been assembled to the rear frame, as viewed from a lateral side; 
         FIG.  16    is an illustration for explaining the first half of a procedure for assembling the electrical box to the rear frame; 
         FIG.  17    is an illustration for explaining the latter half of the procedure for assembling the electrical box to the rear frame; and 
         FIG.  18    is an enlarged view of the circled area XVIII in  FIG.  17   . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, an embodiment of the present invention will be described in detail on the basis of the drawings. It should be noted that the invention is not limited to the embodiment described below. 
     Embodiment 
       FIG.  1    shows an image forming apparatus  1  in this embodiment. The image forming apparatus  1  is composed of, for example, a color laser printer (hereinafter, simply referred to as “printer”)  1 . 
     The image forming apparatus  1  has an image forming apparatus body  100 . The image forming apparatus body  100  has a sheet feeding unit  10 , an image forming unit  20 , and a fixing unit  30  therein, and has a sheet discharging unit  40  on a top surface thereof. A sheet conveyance path L that leads from the sheet feeding unit  10  to the sheet discharging unit  40  has a plurality of conveyance roller pairs  11  to  13  arranged thereon that nip and covey a paper sheet P. A reverse conveyance path L′ is connected to the sheet conveyance path L. The reverse conveyance path L′ branches off from a downstream side of the sheet conveyance path L and connects to an upstream side of the sheet conveyance path L. The reverse conveyance path L′ has conveyance roller pairs  14  to  16  arranged thereon. 
     The sheet feeding unit  10  is arranged below the image forming unit  20 . The sheet feeding unit  10  includes a sheet feed cassette  10   a  that contains paper sheets P, and a pick-up roller  10   b  that picks up paper sheets P from the sheet feed cassette  10   a  and feeds the paper sheets P out of the cassette. The paper sheets P fed out of the sheet feed cassette  10   a  are supplied to the image forming unit  20  through the conveyance roller pair  11 . 
     In the image forming unit  20 , imaging units  20 Bk,  20 M,  20 C, and  20 Y that respectively form toner images corresponding to black, magenta, cyan, and yellow are arranged in one line. Each imaging unit  20 Bk,  20 M,  20 C,  20 Y includes a photosensitive drum  21 , a charging device  22 , a developing device  23 , and a cleaning device  24 . In the figures, reference numerals  21  to  24  are provided only for the imaging unit  20 Y for yellow and are omitted with respect to the other units  20 Bk,  20 M, and  20 C. Below the imaging units  20 Bk,  20 M,  20 C, and  20 Y, an exposure device  25  is arranged that radiates a laser beam to the surface of each photosensitive drum  21 . Above the imaging units  20 Bk,  20 M,  20 C, and  20 Y, an intermediate transferring unit  26  is arranged. 
     The intermediate transferring unit  26  includes an intermediate transfer belt  27 , four primary transfer rollers  28 , and a secondary transfer roller  29 . The intermediate transfer belt  27  rotates in contact with the photosensitive drums  21 . The four primary transfer rollers  28  are arranged inside the intermediate transfer belt  27  such that they sandwich the intermediate transfer belt  27  in cooperation with the photosensitive drums  21 . The secondary transfer roller  29  is arranged on the downstream side of the imaging unit  20 Bk such that the secondary transfer roller  29  is in contact with the surface of the intermediate transfer belt  27 . Above the intermediate transferring unit  26 , tonner containers  50 Bk,  50 M,  50 C, and  50 Y are arranged that respectively contain toners of the colors to be supplied to the developing units  23  of the imaging units  20 Bk,  20 M,  20 C, and  20 Y. 
     In the image forming unit  20 , the exposure device  25  radiates a laser beam based on predetermined image data to the surface of each photosensitive drum  21  to form an electrostatic latent image on the surface of each photosensitive drum  21 , and the formed electrostatic latent image is developed by the developing device  23 , whereby a toner image of each color is formed on the surface of each photosensitive drum  21 . The toner image of each color formed the surface of each photosensitive drum  21  is transferred onto the surface of the intermediate transfer belt  27  by each primary transfer roller  28  such that they are superimposed one upon another. The toner images transferred on the intermediate transfer belt  27  are transferred onto a paper sheet P, which is supplied from the sheet feeding unit  10 , by the secondary transfer roller  29 . The paper sheet P subjected to the transfer is supplied to the fixing unit  30 . In the fixing unit  30 , the paper sheet P supplied from the image forming unit  20  is pressed between a fixing roller  30   a  and a pressure roller  30   b , whereby the toner images are fixed on the paper sheet P. The paper sheet P subjected to the fixing of the toner images in the fixing unit  30  is fed out to the downstream side by the rollers  30   a ,  30   b . The paper sheet P fed out of the fixing unit  30  is discharged to the sheet discharging unit  40  through the transfer roller pairs  12 ,  13 . In the case of forming toner images on both surfaces of a paper sheet P, the paper sheet P is switched back and conveyed to the reverse conveyance path L′ by the transfer roller pair  13 . 
     The image forming apparatus body  100  has a front frame (not illustrated) and a rear frame  101  (an example of the frame side plate, see  FIG.  2   ) made of sheet metal that are opposed to each other in the front-rear direction. The imaging units  20 Bk,  20 M,  20 C, and  20 Y are disposed between the front frame and the rear frame  101 . 
     [Arrangement of Boards] 
     On a rear surface of the rear frame  101 , as shown in  FIGS.  2  and  3   , a high voltage board  60  is mounted on a portion corresponding to the imaging units  20 Bk,  20 M,  20 C, and  20 Y, and an engine board  61  is mounted on a portion corresponding to upper ends of the sheet conveyance path L and reverse conveyance path L′. The high voltage board  60  supplies high voltage to the developing units  23  and the photosensitive drums  21 . The engine board  61  controls operation of a drive motor of the conveyance system and a drive motor of a cooling fan. Behind (i.e., on the rear side of) the high voltage board  60  and the engine board  61 , a control board  62  and an electrical box  70  (not illustrated in  FIGS.  2  and  3   ) housing the control board  62  are arranged. The control board  62  performs control of image processing and control of display. The high voltage board  60  and the engine board  61  correspond to the first electrical board, while the control board  62  corresponds to the second electrical board. 
     [Configuration of Electrical Box] 
       FIGS.  4  to  7    show a state where the electrical box  70  is mounted on the rear frame  101 . The electrical box  70  has a box body  71  and a lid member  72  (an example of the top plate) and, as viewed as a whole, has a rectangular box shape extending in the right-left direction. The electrical box  70  is composed of, for example, sheet metal members. As shown in  FIG.  7   , the electrical box  70  is arranged to cross a boundary position between the high voltage board  60  and the engine board  61  and overlap both the boards  60 ,  61  from the rear side of the boards  60 ,  61  (an example of the outer side of the image forming apparatus body). 
     The box body  71  is composed of a flat and bottomed box-shaped member that is formed such that a base plate  71   e  as a bottom plate of the box body  71  faces the rear frame  101 . The lid member  72  removably closes the open side (rear side) of the box body  71 . As shown in  FIG.  5   , an upper side plate  71   a  of the box body  71  has two brackets for fixation  71   b  (an example of the engaging portion for temporary holding) thereon that are formed to protrude therefrom. As shown in  FIG.  6   , a lower side plate  71   c  of the box body  71  has one bracket for fixation  71   d  thereon that is formed to protrude therefrom. The box body  71  is fixed to the rear frame  101  at three points by bolts  75  (see  FIG.  8   ) penetrating through the brackets for fixation  71   b ,  71   d.    
     As shown in  FIG.  8   , one of the two brackets for fixation  71   b  formed on the upper side plate  71   a  engages with an engagement hook  102 . The engagement hook  102  has a flexible plate part  102   a  connected perpendicularly to a board mounting surface of the rear frame  101 , and a triangular prism-shaped claw part  102   b  formed on a distal end of the flexible plate part  102   a . When the electrical box  70  is assembled to the rear frame  101 , the oblique face of the claw part  102   b  is pushed by the bracket for fixation  71   b  and the flexible plate part  102   a  is thereby deflected. Once the bracket for fixation  71   b  completely passes through the oblique face of the claw part  102   b , the flexible plate part  102   a  returns to its original state by virtue of its own restoring force, so that the claw part  102   b  engages the bracket for fixation  71   b . Thus, the bracket for fixation  71   b  functions as the engaging portion for temporary holding. 
       FIG.  9    shows a state where the lid member  72  is removed from the box body  71  of the electrical box  70 . The box body  71  has bent flanges  71   g  formed on an open side edge thereof, which are used to fix the lid member  72  with screws. 
     The control board  62  is fixed to the base plate  71   e  inside the box body  71 . The control board  62  consists of a first board part  62   a  and a second board part  62   b  that are adjacently arranged side by side, and a connection part  63  that connects the board parts  62   a  and  62   b . The first board part  62   a  has two connectors  64  and  65  at an upper end thereof, which have predetermined communication standards. 
     As shown in  FIG.  10   , the upper side plate  71   a  of the box body  71  has an opening  71   h  formed therein for exposing the two connectors  64 ,  65  to the outside. The opening  71   h  is formed in a slot shape extending in the right-left direction. Mating connectors (not illustrated) fitting with the two connectors  64 ,  65  are to be removably connected to the connectors  64 ,  65  in the vertical direction (i.e., a direction perpendicular to the upper side plate  71   a ) through the opening  71   h.    
     [Configuration of Box Protruding Plate] 
     As shown in  FIGS.  11  and  12   , a box protruding plate  73  is connected to one side end of the box body  71  in the right-left direction. The box protruding plate  73  protrudes to the rear frame  101  side with respect to the base plate  71   e  of the box body  71  when the electrical box  70  has been assembled to the rear frame  101 . The box protruding plate  73  is formed to extend in the vertical direction perpendicularly to the rear frame  101 . The box body  71  side edge of the box protruding plate  73  is bent at a 90-degree angle to form a connection allowance  76 . The box protruding plate  73  extends to a level lower than the lower end of the electrical box  70  when the electrical box  70  has been assembled to the rear frame  101 . That is to say, the vertical dimension of the box protruding plate  73  is longer than the vertical dimension of the electrical box  70 . 
     As shown in  FIG.  12   , the box protruding plate  73  has a pair of engaging plate portions  73   a ,  73   b  (an example of the engaging portion for assembling) provided thereon that are respectively formed on both end portions in the longitudinal direction of the box protruding plate  73 . Each engaging plate portion  73   a ,  73   b  is formed by making a square U-shaped cut in a predetermined portion of the box protruding plate  73  and bending the cut portion to one side in the thickness direction of the box protruding plate  73 . That is to say, each engaging plate portion  73   a ,  73   b  is formed by a cutout piece protruding to one side in the thickness direction of the box protruding plate  73 . 
     [Configuration of Frame Protruding Plate] 
     As shown in  FIG.  13   , the rear frame  101  of the image forming apparatus body  100  has a frame protruding plate  103  formed thereon. The frame protruding plate  103  is positioned at the left end of the rear frame  101  and formed to protrude perpendicularly to the rear frame  101  and extend in the vertical direction. 
     The frame protruding plate  103  has a pair of engaged portions  103   a ,  103   b  (an example of the first engaged portion) provided at a protruding side end thereof, which engages with the engaging plate portions  73   a ,  73   b  formed on the box protruding plate  73 . 
     The pair of engaged portions  103   a ,  103   b  are formed with a sufficient distance therebetween in the vertical direction. This distance is set to be greater than the vertical dimension of the electrical box  70 . 
     The upper engaged portion  103   a  is adjacent to an upper end surface of a square U-shaped protrusion  103   c  formed at an upper end portion of the frame protruding plate  103 , while the lower engaged portion  103   b  is adjacent to an upper end surface of a square U-shaped protrusion  103   d  formed at a lower end portion of the frame protruding plate  103 . The square U-shaped protrusions  103   c ,  103   d  adjacent to the engaged portions  103   a ,  103   b  restrict downward movement of the engaging plate portions  73   a ,  73   b.    
     [Configuration of Positioning Plate] 
     As shown in  FIG.  14   , the box body  71  has, in addition to the box protruding plate  73 , a box positioning plate  74  provided thereon. 
     The box positioning plate  74  is formed at an intermediate portion of the base plate  71   e  of the box body  71  in the right-left direction to protrude therefrom and extend in parallel to the box protruding plate. 
     The box positioning plate  74  has a plurality of (in this embodiment, by way of example, three) engaging protrusions  74   a  (an example of the positioning engaging portion) formed on a protruding side end thereof. The engaging protrusions  74   a  are formed by forming a plurality of slit grooves in the protruding side end of the box positioning plate  74 . 
     As shown in  FIG.  15   , when assembling of the electrical box  70  is completed, the three engaging protrusions  74   a  formed on the box positioning plate  74  engage with cutouts  104   a  (an example of the second engaged portion) of an engaged plate  104  formed on the rear side of the rear frame  101  to stand therefrom. The cutouts  104   a  have a fitting shape fitting with the engaging protrusions  74   a . The cutouts  104   a  fit (engage) with the engaging protrusions  74   a  to restrict movement of the engaging protrusions  74   a  in the vertical direction. 
     [Procedure for Assembling Electrical Box to Rear Frame] 
     Next, a procedure for assembling the electrical box  70  to the rear frame  101  is described with reference to  FIGS.  16  to  18   .  FIGS.  16  and  17    show the positional relation between the electrical box  70  and the rear frame  101  during assembling as viewed from below.  FIG.  18    is an enlarged view of the circled area XVIII in  FIG.  17   . 
     As shown in  FIG.  16   , with the electrical box  70  in the vertically standing position, an operator first adjusts the position of the box protruding plate  73  in the right-left direction so that it approximately coincides with the position of the frame protruding plate  103  of the rear frame  101  in the right-left direction. 
     Substantially, as shown in  FIGS.  17  and  18   , the operator brings the box protruding plate  73  side of the box body  71  close to the frame protruding plate  103  and inclines the electrical box  70  as a whole toward the mounting surface of the rear frame  101 . 
     Subsequently, the operator brings the pair of engaging plate portions  73   a ,  73   b  (in  FIG.  17   , only one is shown) formed on the box protruding plate  73  into contact (an example of the engagement) with the pair of engaged portions  103   a ,  103   b , respectively. This state is not illustrated as a perspective view; however, this state can be easily understood with reference to the illustration in  FIG.  13    (the illustration of the state where the assembling has been completed). Thereafter, the operator turns the electrical box  70  as a whole around an axis extending in the vertical direction (an axis extending in the direction perpendicular to the drawing sheet in  FIG.  17   ), with the pair of engaged portions  103   a ,  103   b  as the fulcrum. Once the electrical box  70  is rotated to the position at which the base plate  71   e  of the box body  71  becomes parallel to the rear frame  101 , the engaging protrusions  74   a  of the box positioning plate  74  described in relation to  FIG.  15    engage the cutouts  104   a  of the engaged plate  104  standing from the rear frame  101 , and the engagement hook  102  described in relation to  FIG.  8    engages the bracket for fixation  71   b  of the box body  71 . Thereby, the electrical box  70  is temporarily held by the rear frame  101 , so that the position of the electrical box  70  is maintained even when the operator releases his/her hands from the electrical box  70 . After the assembling of the electrical box  70  to the rear frame  101  is completed in this manner, the brackets for fixation  71   b ,  71   d  of the box body  71  (see  FIG.  14   ) are fixed to the rear frame  101  with bolts, whereby fixation of the electrical box  70  to the rear frame  101  is completed. 
     [Operational Effects] 
     As described above, in this embodiment, the mounting surface of the rear frame  101  on which the high voltage board  60  and the engine board  61  are mounted has the frame protruding plate  103  provided thereon that is formed perpendicularly to the mounting surface and protrudes outward of the image forming apparatus body  100 . The electrical box  70  has the box protruding plate  73  that overlaps the side surface of the frame protruding plate  103  when assembling of the electrical box  70  to the rear frame  101  is completed, and also has the engaging plate portions  73   a ,  73   b  that protrude in the thickness direction from the box protruding plate  73 . When the electrical box  70  is assembled to the rear frame  101 , the engaging plate portions  73   a ,  73   b  of the box protruding plate  73  are engaged with the engaged portions  103   a ,  103   b  formed on the protruding side end of the frame protruding plate  103 , and in this state the electrical box  70  as a whole is turned around an axis parallel to the extending direction of the frame protruding plate  103  (in this embodiment, an axis extending in the vertical direction) with the engaged portions  103   a ,  103   b  as the fulcrum, so that the trajectory of the electrical box  70  during the assembling is restricted. 
     Therefore, even if the operator&#39;s field of view is obstructed by the electrical box  70  when the operator arranges the electrical box  70  over the high voltage board  60  and the engine board  61  after the mounting of the boards  60 ,  61  onto the rear frame  101 , the operator can assemble the electrical box  70  to a predetermined position without the electrical box  70  interfering with the boards  60 ,  61 . Thus, it is possible to prevent the boards  60 ,  61  from being damaged due to interference with the electrical box  70  during the assembling of the electrical box  70 . Further, it is possible to safely assemble the electrical box  70  to the rear frame  101  without depending on the level of the operator&#39;s assembling skill. 
     Further, in this embodiment, the frame protruding plate  103  extends in the vertical direction; therefore, the axis serving as the fulcrum for rotation of the electrical box  70  also extends in the vertical direction. Therefore, the electrical box  70  is less likely to rotate or fall off due to its own weight during the assembling than in the case where the electrical box  70  is rotated around a horizontal axis. This improves the workability in assembling the electrical box  70 . 
     The engaged portions  103   a ,  103   b  of the frame protruding plate  103  are formed at positions adjacent to the upper sides of the square U-shaped protrusions  103   c ,  103   d , respectively. According to this configuration, downward movement of the engaging plate portions  73   a ,  73   b  of the box protruding plate  73  is restricted when the engaging plate portions  73   a ,  73   b  are in engagement with the engaged portions  103   a ,  103   b.    
     This ensures that the electrical box  70  is prevented from falling off due to its own weight when it is rotated with the engaged portions  103   a ,  103   b  as the fulcrum. Therefore, the workability in assembling the electrical box  70  is more improved. 
     Further, in this embodiment, the box body  71  of the electrical box  70  has the box positioning plate  74  provided thereon that has the engaging protrusions  74   a.  Further, the rear frame  101  has the cutouts  104   a  provided thereon that engage with the engaging protrusions  74   a  of the electrical box  70  when the electrical box  70  as a whole is rotationally moved to (reaches) a predetermined assembling position, thereby restricting downward movement of the engaging protrusions  74   a.    
     According to this configuration, the electrical box  70  is prevented from falling off due to its rotation in a plane parallel to the rear frame  101  caused by its own weight. 
     Further, in this embodiment, the rear frame  101  has the engagement hook  102  formed thereon that protrudes therefrom. The engagement hook  102  engages with the bracket for fixation  71   b  of the box body  71  when the electrical box  70  as a whole is rotationally moved to (reaches) the predetermined assembling position, thereby temporarily holding the electrical box  70  so that the electrical box  70  does not fall down in a direction away from the rear frame  101 . 
     According to this configuration, the electrical box  70  is temporality held by the rear frame  101  without falling down to the operator side (the rear side) even when the operator releases his/her hands from the electrical box  70  after assembling the electrical box  70  to the rear frame  101 . Therefore, the operator can move smoothly to the fixation of the electrical box  70  with bolts. 
     Further, in this embodiment, the control board  62  housed by the electrical box  70  has the connectors  64 ,  65 . Further, the electrical box  70  has the base plate  70   e  and the lid member  72  that are opposed to each other in the direction perpendicular to the rear side of the rear frame  101 , and the side plates that stand from the base plate  70   e  and extend to the lid member  72 . The upper side plates  71   a  has the opening  70   h  formed therein for exposing the connectors  64 ,  65  to the outside. The mating connectors (not illustrated) fitting with the connectors  64 ,  65  are configured to be able to be inserted into and pulled out of the connectors  64 ,  65  of the control board  62  in the direction perpendicular to the side plate  71   a  through the opening  71   h.    
     According to this configuration, the connection and removal of wires to and from the control board  62  can be performed from a lateral side of the electrical box  70 . Therefore, for example, when detaching the electrical box  70  from the rear frame  101 , the operator does not need bother to remove the lid member  72  to access the connectors  64 ,  65  inside the box body  71 . All the operator needs to do to complete the operation is to remove the bolts  75  (see  FIG.  8   ) fixing the electrical box  70  to the rear frame  101 . Therefore, detachment of the electrical box  70  in the event of a fault or for maintenance can be easily performed. 
     Other Embodiments 
     The present invention may have the following configurations in relation to the above-described embodiment. 
     That is to say, in the above-described embodiment, the trajectory of the electrical box  70  is restricted by turning the electrical box  70  around an axis extending in the vertical direction with the engaged portions  103   a ,  103   b  of the frame protruding plate  103  as the fulcrum. However, the present invention is not limited to this configuration and, for example, a configuration is possible in which the frame protruding plate  103  extends in the right-left direction and the electrical box  70  is turned around a horizontal axis. 
     In the above-described embodiment, the image forming apparatus  1  is a tandem color image forming apparatus. However, the present invention is not limited thereto and the image forming apparatus  1  may be a monochrome image forming apparatus. 
     Furthermore, the above-described embodiment is described with respect to an example in which the image forming apparatus  1  is a printer. However, the present invention is not limited thereto and the image forming apparatus  1  may be, for example, a copying machine, a facsimile, a multifunction peripheral (MFP), or the like. 
     INDUSTRIAL APPLICABILITY 
     As described above, the present invention is useful with an image forming apparatus, and in particular useful for application to a printer, a facsimile, a copying machine, or a multifunction peripheral (MFP).