Abstract:
An image forming apparatus, comprising: a housing having an opening through which a recording medium passes, the housing comprising a container unit configured to support at least a part of the recording medium passed through the opening; a feed roller configured to feed the recording medium supported in the container unit to an image formation unit; and a fan configured to cause air in the housing to flow, wherein the container unit comprises: a stacker part to support at least the part of the recording medium; and a pair of side parts disposed to sandwich the stacker part between the pair of side parts, in an orthogonal direction perpendicular to a feeding direction of the feed roller, and the fan is disposed at one of the pair of side parts and at a position closer to the opening relative to the feed roller in the feeding direction.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority under 35 U.S.C. §119 from Japanese Patent Application No. 2013-201654, filed on Sep. 27, 2013. The entire subject matter of the application is incorporated herein by reference. 
       BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    Aspects of the present invention relate to an electrophotographic type image forming apparatus. 
         [0004]    2. Related Art 
         [0005]    Conventionally, image forming apparatuses comprising a box-shaped main body, an image formation unit provided in the main body and a fan have been proposed. For example, one of such image forming apparatuses further comprises therein a duct through which a flowing path of air is formed. In this example, the duct is fixed to a left surface of a left frame of the main body, and the fan is supported by the duct such that the fan is disposed to have an interval, on the left side, with respect to the left frame. In this configuration, air in the duct is discharged leftward. 
       SUMMARY 
       [0006]    Recently, a demand for enhancing a degree of freedom regarding an installation space for an image forming apparatus is increasing. However, when the image forming apparatus of the above described type is placed to adjoin an installed object, such as a wall, on the right side of the installed object, the fan is also disposed to adjoin the installed object on the right side of the installed object. In this case, air discharge by the fan may be hampered. As a result, flowing of air in the duct is restricted, and thereby heat cannot be radiated adequately. 
         [0007]    Aspects of the present invention are advantageous in that an image forming apparatus capable of causing air in a housing to smoothly flow even when the image forming apparatus is placed next to an installed object. 
         [0008]    According to an aspect of the invention, there is provided an image forming apparatus, comprising: a housing having an opening through which a recording medium passes, the housing comprising a container unit configured to support at least a part of the recording medium passed through the opening; a feed roller configured to feed the recording medium supported in the container unit to an image formation unit; and a fan configured to cause air in the housing to flow. The container unit comprises: a stacker part configured to support at least the part of the recording medium; and a pair of side parts disposed to sandwich the stacker part between the pair of side parts, in an orthogonal direction which is perpendicular to a feeding direction of the feed roller. The fan is disposed at one of the pair of side parts and at a position closer to the opening relative to the feed roller in the feeding direction. 
     
    
     
       BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS 
         [0009]      FIG. 1  is a central cross section of a printer according to an embodiment, illustrating a situation where a paper supply cover is at a closed position. 
           [0010]      FIG. 2  is a perspective view of the printer shown in  FIG. 1  viewed from a front left side and illustrates a situation where the paper supply cover is at an opened position. 
           [0011]      FIG. 3  is a right side view of the printer shown in  FIG. 1 . 
           [0012]      FIG. 4  is a central cross section of the printer shown in  FIG. 2 , illustrating a situation where the paper supply cover is at the opened position. 
           [0013]      FIG. 5  is a cross section of the printer cut along a line C-C in  FIG. 4 . 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    Hereafter, an embodiment according to the invention will be described with reference to the accompanying drawings. 
         [0015]    1. Overall Configuration of Printer 
         [0016]    As shown in  FIG. 1 , a printer  1  (an example of an image forming apparatus) includes a body casing  2 . The body casing  2  is formed in a box shape, and accommodates therein a paper supply unit  3  configured to supply a sheet of paper P (an example of a recording medium), and an image formation unit  4  configured to form an image on the supplied sheet of paper P. 
         [0017]    In the following explanation, when a direction is referred to, the right side on the paper face of  FIG. 1  is defined as the front side, and the left side on the paper face of  FIG. 1  is defined as the rear side with respect to a state where the printer  1  is placed horizontally. The left and right direction is defined with reference to a state where the printer  1  is viewed from the front side, and the forehand side of the paper face of  FIG. 1  is the left side and the back side of the paper face of  FIG. 1  is the right side. The upper side in the paper face of  FIG. 1  is the upper side, and the lower side in the paper face of  FIG. 1  is the lower side. That is, each of the left and right direction and the front and rear direction is a horizontal direction, and the up and down direction is the vertical direction. Further, as shown in  FIG. 4 , a direction pointing to the rear side from the front side is a feeding direction X. 
         [0018]    (1) Body Casing 
         [0019]    As shown in  FIG. 1 , the body casing  2  includes a cartridge opening  5  and a paper opening  6 . The cartridge opening  5  is disposed at the upper edge part of the body casing  2 , and lets the inside and the outside of the body casing  2  communicate with each other. The cartridge opening  5  is formed to have a size and a shape for letting a process cartridge  15  (which is described later) pass therethrough. 
         [0020]    The paper opening  6  is disposed at the front edge part of the body casing  2  to penetrate through a lower part of the front edge part of the body casing  2  in the front and rear direction. Further, as shown in  FIG. 1 , the body casing  2  includes a top cover  7  and a paper supply cover  8 . The top cover  7  is disposed at the upper edge part of the body casing  2  so as to cover the cartridge opening  5  from the upper side. The top cover  7  is formed in a shape of a crank when viewed as a side view, and is formed in a rectangular shape when viewed as a plan view. 
         [0021]    The top cover  7  includes a paper discharge tray  35 . The paper discharge tray  35  is formed to be a recessed part of which front part is recessed downward, and is opened toward the upper side. When viewed as a side view, the top cover  7  is formed in a shape of a letter U. 
         [0022]    The top cover  7  is configured to swing about the rear edge part between a closed position where the cartridge opening  5  is closed and an opened position where the cartridge opening  5  is opened. In  FIG. 1 , the top cover  7  disposed at the closed position is indicated by a slid line, and the top cover  7  disposed at a position between the closed position and the opened position is indicated by a virtual line. 
         [0023]    The paper supply cover  8  is disposed in the front edge part of the body casing  2  to cover the paper opening  6  from the front side. The paper supply cover  8  is swingable about a lower end thereof between a closed position where the paper opening  6  is closed and an opened position where the paper opening  6  is opened as shown in  FIG. 2 . In  FIG. 1 , the paper supply cover  8  at the closed position is indicated by a solid line, and the paper supply cover  8  at a position between the closed position and the opened position is indicated by a virtual line. 
         [0024]    (2) Paper Supply Unit 
         [0025]    The paper supply unit  3  is configured to supply the sheet of paper  3  to the image formation unit  4 , and is disposed in a bottom portion of the body casing  2 . The paper supply unit  3  includes a paper container  9 , a pickup roller  11 , a paper supply roller  12 , a paper supply pad  13  and a paper supply path  14 . As described in detail later, the paper container  9  is configured to define a paper container space S 1  in which the rear part of the sheet of paper P is supported. The paper container space S 1  communicates with the outside of the body casing  2  in the front and rear direction via the paper opening  6 . It should be noted that a feeding direction of the paper supply roller  12  is defined as the feeding direction X. 
         [0026]    The pickup roller  11  is disposed on the upper rear side of the paper container  9  to face the upper rear edge of the paper container space S 1 . The paper supply roller  12  is disposed on the rear side of the pickup roller  11  to have an interval therebetween. Further, the paper supply roller  12  is disposed at a position lower than an upper edge  90  of the paper opening  6 . That is, when viewed along the front and rear direction, the paper supply roller  12  is disposed to overlap with the paper opening  6 . The paper supply pad  13  is disposed on the lower side of the paper supply roller  12  to contact the lower rear edge of the paper supply roller  12 . The paper supply path  14  is provided to extend continuously from the rear edge of the paper supply pad  13 . 
         [0027]    (3) Image Formation Unit 
         [0028]    The image formation unit  4  includes the process cartridge  15 , a scanner unit  16  and a fixing unit  17 . The process cartridge  15  is configured to form a toner image on the sheet of paper P, and to be detachably attachable to the body casing  2 . The process cartridge  15  includes a drum cartridge  18  and a development cartridge  19 . The drum cartridge  18  includes a drum frame  23 , a photosensitive drum  20 , a transfer roller  21  and a scorotron charger  22 . 
         [0029]    The drum frame  23  is formed in a rectangular frame shape having a bottom. The drum frame  23  includes a pair of drum side walls (not shown), a drum front wall  92 , a drum bottom wall  93 , a charge support wall  94 , and a roller container wall  95 . The pair of drum side walls (not shown) are provided to face with each other to have an interval therebetween in the left and right direction. 
         [0030]    The drum front wall  92  is provided to extend between front edge parts of the pair of drum side walls (not shown). The drum bottom wall  93  is provided to extend between lower edge parts of the pair of drum side walls (not shown). Further, the front edge part of the drum bottom wall  93  is connected to the lower edge part of the drum front wall  92 . 
         [0031]    The charge support wall  94  is provided to extend between upper rear edge parts of the pair of drum side walls (not shown). The charge support wall  94  has a shape of a square cylinder extending in the left and right direction. The roller container wall  95  is provided to extend between lower rear edge parts of the pair of drum side walls (not shown). Further, the roller container wall  95  is disposed on the lower rear side with respect to the charge support wall  94  to have an interval therebetween, and is disposed on the upper rear side with respect to the drum bottom wall  93  to have an interval therebetween. The charge support wall  94  is formed in a shape of a letter U which is opened toward the front side when viewed as a side view. 
         [0032]    The photosensitive drum  20  is formed in a cylindrical shape extending in the left and right direction, and is rotatably supported in a rear portion of the drum frame  23 . 
         [0033]    The transfer roller  21  is formed in a cylindrical shape extending in the left and right direction, and is disposed on the rear side of the photosensitive drum  20  in the roller container wall  95 . The front edge part of the transfer roller  21  contacts the rear edge part of the photosensitive drum  20 . Further, the transfer roller  21  is rotatably supported by the drum frame  23 . 
         [0034]    The scorotron charger  22  is disposed on the upper front side of the photosensitive drum  20  to have an interval therebetween, and is supported by the charge support wall  94 . The development cartridge  19  is configured to be detachably attachable to the drum frame  23 , and is disposed on the lower front side of the photosensitive drum  20  in a state where the development cartridge  19  is attached to the drum frame  23 . 
         [0035]    The development cartridge  19  includes a development frame  24 , an agitator  30 , a development roller  25 , a supply roller  26  and a layer thickness limiting blade  27 . 
         [0036]    The development frame  24  is formed in a box-shape extending in the left and right direction, and the rear edge part of the development frame  24  is opened in the front and rear direction. Further, the development frame  24  includes therein a toner reservoir  28  and a development chamber  29  which are arranged in the front and rear direction. The toner reservoir  28  stores toner which is an example of a developer. 
         [0037]    The agitator  30  is disposed in a central portion in the up and down direction and in the front and rear direction in the toner reservoir  28 . Further, the agitator  30  is rotatably supported by the development frame  24 . 
         [0038]    The development roller  25  is disposed in the rear edge portion of the development chamber  29 . The development roller  25  is formed in a cylindrical shape extending in the left and right direction, and is rotatably supported by the development frame  24 . Further, the upper part and the rear part of the development roller  25  are exposed from the development frame  24 , and the upper rear edge part of the development roller  25  contacts the lower front edge part of the photosensitive drum  20 . 
         [0039]    The supply roller  26  is disposed on the lower front side of the development roller  25  in the development chamber  29 . The supply roller  26  is formed in a cylindrical shape extending in the left and right direction, and is rotatably supported by the development frame  24 . The upper rear edge part of the supply roller  26  contacts the lower front edge part of the development roller  25 . 
         [0040]    The layer thickness limiting blade  27  is disposed on the upper front side of the development roller  25 . The layer thickness limiting blade  27  is a plate-like member extending in the left and right direction and has a rectangular shape when viewed from the rear side. Further, the layer thickness limiting blade  27  is supported by the development frame  24  such that the lower edge of the layer thickness limiting blade  27  contacts the front edge part of the development roller  25 . 
         [0041]    In order to attach the process cartridge  15  to the body casing  2 , the top cover  7  is disposed at the opened position, and the process cartridge  15  is attached to or detached from the body casing  2  via the cartridge opening  5 . 
         [0042]    In the state where the process cartridge  15  is attached to the body casing  2 , the process cartridge  15  is disposed above the rear part of the paper supply unit  3 , specifically, above the pickup roller  11  and the paper supply roller  12 . In the state where the process cartridge  15  is attached to the body casing  2 , the lower edge part of the drum front wall  92  is disposed at the front edge part of the process cartridge  15 , the lower edge part of the drum front wall  92  is disposed at the lower edge part  91  of the process cartridge  15 , the upper rear edge part of the charge support wall  94  is disposed at the upper edge part of the drum cartridge  18 , and the rear edge part of the roller container wall  95  is disposed at the rear edge part of the drum cartridge  18 . That is, the lower edge part  91  of the process cartridge  15  attached to the body casing  2  corresponds to the lower edge part of the drum front wall  92 . 
         [0043]    The lower edge part  92  of the process cartridge  15  faces the paper container space S 1 , and is disposed on a lower side with respect to the upper edge  90  of the paper opening  6 . 
         [0044]    The scanner unit  16  is disposed on the front side of the process cartridge  15  in the body casing  2 , and is disposed on the upper side with respect to the paper opening  6 . As indicated by a solid line in  FIG. 1 , the scanner unit  16  emits a laser beam based on image data toward the photosensitive drum  20  to expose the circumferential surface of the photosensitive drum  20 . 
         [0045]    The fixing unit  17  is disposed on the upper side of the rear part of the process cartridge  15  in the body casing  2 . Further, the fixing unit  17  is disposed to overlap with the process cartridge  15  and the paper supply roller  12  when viewed in the up and down direction. That is, the process cartridge  15 , the fixing unit  17  and the development roller  12  overlap with each other when viewed in the up and down direction. 
         [0046]    The fixing unit  17  includes a heat roller  31  and a pressure roller  32 . The pressure roller  32  is disposed on the upper rear side with respect to the heat roller  31 , and the lower front edge of the pressure roller  32  contacts the upper rear edge of the heat roller  31 . 
         [0047]    2. Details of Body Casing 
         [0048]    As shown in  FIGS. 1 and 2 , the body casing  2  includes a pair of side walls  40 , a front wall  41 , a bottom wall  42  and a rear wall  43 . The pair of side walls  40  is disposed at the left and right edges of the body casing  2  to have an interval therebetween. Each of the pair of side walls  40  has a rectangular shape when viewed as a side view as shown in  FIG. 3 , and includes a main frame  45  and a side cover  46  as shown in  FIG. 5 . 
         [0049]    When the main frame  45  of the right side wall  40  is explained distinctively from the main frame  45  of the left side wall  40 , the main frame  45  provided on the right side is referred to as a right main frame  45 R and the main frame  45  provided on the left side is referred to as a left main frame  45 L. Further, when the side cover  46  of the right side wall  40  is explained distinctively from the side cover  46  of the left side wall  40 , the side cover  40  provided on the right side is referred to as a right side cover  46 R, and the side cover  46  provided on the left side is referred to as a left side cover  46 L. 
         [0050]    The main frame  45  is provided in a space between the side walls  40  in the left and right direction. The main frame  45  is made of known resin, and has a box shape opened outward in the left and right direction. Further, the main frame  45  includes a plate  51  and a peripheral wall  52  which are formed integrally. 
         [0051]    The plate  51  is a plate-like member having a rectangular shape when viewed as a side view, and includes a lower part  47  and an upper part  48 . The lower part  47  is a lower part of the plate  51  with respect to a central part of the plate  51  in the up and down direction, and the upper part  48  is an upper part of the plate  51  with respect to the central part of the plate  51  in the up and down direction. 
         [0052]    The peripheral wall  52  is formed to project outward from the peripheral edge of the plate  51  in the left and right direction. That is, each of the cross sections of the main frame  45  defined by cutting along the up and down direction and the front and rear direction is formed in a shape of a letter U. 
         [0053]    As shown in  FIGS. 4 and 5 , the right main frame  45 R has a communication opening  50 . The communication opening  50  corresponds to a space for a fan  80  which is described later, and is disposed at the front edge part of the lower part  47  of the plate  51 . 
         [0054]    The communication opening  50  includes a plurality of holes  49 . Each hole  49  has a circular shape when viewed as a side view, and penetrates the plate  51  in the left and right direction as shown in  FIG. 5 . Further, the plurality of holes  49  are disposed to have intervals therebetween in the radial direction of each hole  49 . 
         [0055]    As shown in  FIG. 5 , the side cover  46  is a side part of each side wall  40  in the left and right direction, and constitutes an exterior of each side wall  40 . The side cover  46  covers the main frame  45  in the left and right direction from the outside. The side cover  46  is made of known resin, and, as shown in  FIG. 2  the side cover  46  is a plate-like member having substantially the same size as that of the main frame  45 . Further, both edge parts in the front and rear direction of the side cover  46  are formed to be bent inward in the left and right direction so as to cover the both edges in the front and rear direction of the main frame  45 . 
         [0056]    As a result, each side wall  40 , i.e., the main frame  45  and the side cover  46 , constitutes an enclosure  54  defining therein a container space S 2 . 
         [0057]    The right side cover  46 R has a ventilation hole  55  as shown in  FIG. 3 . The ventilation hole  55  is disposed at the rear part in the upper edge part of the right side cover  46 R, and is disposed on the upper side with respect to the process cartridge  15  as shown in  FIG. 1 . Further, the ventilation hole  55  is aligned with the process cartridge  15  in the up and down direction when viewed in the left and right direction. 
         [0058]    Further, the ventilation hole  55  includes a plurality of slits  56 . Each slit  56  is formed in a linear shape extending in the front and rear direction when viewed as a side view, and penetrates the right side cover  46 R in the left and right direction. The plurality of slits  56  are arranged in the up and down direction at constant intervals. The ventilation hole  55  (i.e., the plurality of slits  56 ) lets the container space S 2  in the enclosure  54  communicate with the outside of the body casing  2 . 
         [0059]    The front wall  41  is a plate-like member having a rectangular shape extending in the left and right direction when viewed as a front view. Further, the front wall  41  is provided to extend between the upper part  48  of the plate  51  of the right main frame  45 R and the upper part  48  of the plate  51  of the left main frame  45 L. 
         [0060]    The bottom wall  42  is disposed at the lower edge part of the body casing  2 . The bottom wall  42  is a plate-like member having a rectangular shape when viewed as a bottom view. Further, the bottom wall  42  is provided to extend between the lower edge part of the plate  51  of the right main frame  45 R and the lower edge part of the plate  51  of the left main frame  45 L. 
         [0061]    As shown in  FIG. 5 , the bottom wall  42  has restriction guide grooves  57 . The restriction guide grooves  57  are provided respectively for a pair of paper restriction parts  60  and are disposed at both edge parts of the upper surface of the bottom wall  42  in the left and right direction. The restriction guide groove  57  has a rectangular shape extending in the front and rear direction when viewed as a plan view, and is formed to be recessed downward from the upper surface of the bottom wall  42 . 
         [0062]    The rear wall  43  is disposed at the rear edge part of the body casing  2 . The rear wall  43  is a plate-like member formed in a rectangular shape when viewed as a rear view. The rear wall  43  is provided to extend between the rear edge part of the plate  51  of the right main frame  45 R and the rear edge part of the plate  51  of the left main frame  45 L. 
         [0063]    As shown in  FIG. 2 , the lower edge of the front wall  41 , the front edge of the lower part  47  of each plate  51  and the front edge of the bottom wall  42  define the paper opening  6 . That is, the upper edge  90  of the paper opening  6  is the lower edge of the front wall  41 . 
         [0064]    The paper opening  6  is formed in a rectangular shape extending in the left and right direction when viewed as a side view, and an opening plane of the paper opening  6  is formed to extend in the up and down direction and in the left and right direction. Therefore, the opening plane of the paper opening  6  perpendicularly intersects with the feeding direction X which is described later. Further, the size of the paper opening  6  in the left and right direction is longer than the size in the left and right direction of the maximum size of the sheet of paper P which can be used for image formation in the printer  1 . 
         [0065]    The lower part  47 , the bottom wall  42  and the lower edge part of the rear wall  43  of each plate  51  constitute the paper container  9 . That is, the paper container  9  includes the bottom wall  42  and the lower parts  47  of the pair of plates  51 . The paper container space S 1  in the paper container  9  and the outside of the body casing  2  communicate with each other via the paper opening  6 . 
         [0066]    The paper container  9  includes the pair of paper restriction parts  60 . As shown in  FIGS. 2 and 5 , the pair of paper restriction parts  60  is disposed on the upper surface of the bottom wall  42 . The pair of paper restriction parts  60  is disposed to have an interval therebetween in the left and right direction. Each of the pair of paper restriction parts  60  includes a guide plate  61 , a first restriction plate  62  and a second restriction plate  63  which are integrally provided. 
         [0067]    As shown in  FIG. 5 , the guide plate  61  corresponds to the lower edge part of each paper restriction part  60 , and is a plate-like member having a rectangular shape extending in the front and rear direction when viewed as a plan view. The size of the guide plate  61  in the left and right direction is shorter than the size of the restriction guide groove  57  in the left and right direction, and the size of the guide plate  61  in the front and rear direction is substantially equal to the size of the restriction guide groove  57  in the front and rear direction. 
         [0068]    The first restriction plate  62  is configured to restrict movement of the sheet of paper P supported at the paper container  9  in the left and right direction. The first restriction plate  62  is formed to continuously extend upward from the outer edge parts of the guide plate  61  in the left and right direction. The size of the first restriction plate  62  in the up and down direction is shorter than the size of the lower part  47  of the plate  51  in the up and down direction, and the size of the first restriction plate  62  in the front and rear direction is substantially equal to the size of the guide plate  61  in the front and rear direction. 
         [0069]    The second restriction plate  63  is configured to restrict the number of sheets of paper P supported at the paper container  9 . As shown in  FIG. 2 , the second restriction plate  63  is a plate-like member having a shape of a letter L when viewed as a front view. The second restriction plate  63  extends continuously in the left and right direction from the front edge of the upper edge part of the first restriction plate  62  and is bent to extend upward. Further, as shown in  FIG. 5 , the upper edge part of the second restriction plate  63  is disposed at a position lower than the upper edge of the lower part  47  of the plate  51 . 
         [0070]    Since the guide plate  61  is disposed in the restriction guide groove  57 , the paper restriction part  60  is supported by the bottom wall  42  to be slidable in the left and right direction. The pair of paper restriction parts  60  is formed to move in conjunction with each other by a link mechanism (not shown). Therefore, when one of the pair of paper restriction parts  60  slides inward in the left and right direction, the other of the paper restriction parts  60  also slides inward in the left and right direction. Further, when one of the paper restriction parts  60  slides outward in the left and right direction, the other of the pair of paper restriction parts  60  also slides outward in the left and right direction. 
         [0071]    When the pair of paper restriction parts  60  are disposed to have the maximum interval therebetween in the left and right direction, the first restriction plate  62  of each paper restriction part  60  is disposed to have an interval on the inside in the left and right direction with respect to the lower part  47  of the corresponding plate  51 , and the interval in the left and right direction of the first restriction plate  62  is substantially equal to the size in the left and right direction of the sheet of paper P for which the image formation can be executed in the printer  1 . 
         [0072]    As shown in  FIGS. 2 and 4 , the paper supply cover  8  is supported by the pair of side walls  40 . As shown in  FIG. 4 , the paper supply cover  8  includes a rotation shaft  65  and a cover body  66 . 
         [0073]    The rotation shaft  65  has as a cylindrical shape extending in the left and right direction. The cover body  66  is a plate-like member, and is formed to extend, from the rotation shaft, outward in the radial direction of the rotation shaft  65 . The both ends of the rotation shaft  65  protrude outward in the left and right direction from the cover body  66 . 
         [0074]    The paper supply cover  8  is supported by the body casing  2  such that the left and right ends of the rotation shaft  65  are rotatably supported by the lower front edge parts of the pair of main frames  45 , respectively. As shown in  FIG. 4 , in the state where the paper supply cover  8  is disposed at the opened position, the upper surface of the cover body  66  and the upper surface of the bottom wall  42  are substantially in the same plane. 
         [0075]    3. Details of Control Unit 
         [0076]    As shown in  FIG. 5 , the printer  1  includes a control unit  70  and the fan  80 . The control unit  70  and the fan  80  are disposed in the enclosure  54  of the right side wall  40  (i.e., in the container space S 2 ). Motor and a gear train for inputting a driving force into the image formation unit  4  are disposed in the enclosure  54  of the left side wall  40  although these are not shown in the drawings. 
         [0077]    The control unit  70  is configured to control operations of the image formation unit  4 , and includes a low voltage power source board  71  and a control circuit board (not shown). The low voltage power source board  71  is disposed on the right side with respect to the fan  80 , and is fixed to the right surface of the plate  51  of the right main frame  45 R. That is, the low voltage power source board  71  is disposed on the opposite side of the paper container unit  9  with respect to the plate  51  of the right main frame  45 R. 
         [0078]    The low voltage power source board  71  includes a substrate main body  72  and a power source component  73 . The substrate main body  72  is a plate-like member having a rectangular shape when viewed as a side view and extending in the front and rear direction. The substrate main body  72  is disposed on the right side with respect to the lower part  47  of the plate  51  to have an interval between the substrate main body  72  and the lower part  47 , and is disposed on the left side with respect to the lower part of the right side cover  46 R to have an interval between the substrate main body  72  and the lower part of the right side cover  46 R. That is, the right side cover  46 R is disposed on the opposite side of the plate  51  of the right mainframe  45 R with respect to the substrate main body  72 . 
         [0079]    The substrate main body  72  is disposed on the upper side of the lower edge part of the peripheral wall  52  of the right main frame  45 R to have an interval therebetween. The substrate main body  72  is electrically connected to the scorotron charger  22 , the transfer roller  21 , the development roller  25  and the supply roller  26  via wiring and electrodes (not shown). The power source component  73  is attached to the front edge part of the left surface of the substrate main body  72 , and is disposed on the right side of the communication opening  50  to have an interval therebetween. 
         [0080]    The control circuit board (not shown) is electrically connected to the low voltage power source board  71  via wiring, and is configured to control the low voltage power source board  71 . 
         [0081]    The fan  80  is disposed on the lower front part in the enclosure  54 . Specifically, the fan  80  is attached to the right surface of the front edge part of the lower part  47  of the plate  51 , to adjoin the communication opening  50  on the right side of the communication opening  50 . As a result, the fan  80  is sandwiched between the low voltage power source board  71  and the lower part  47  of the plate  51 , and faces the left surface of the substrate main body  72 . That is, the low voltage power source board  71  is disposed on the opposite side of the plate  51  with respect to the fan  80 . The power source component  73  is opposite the fan  80 . The power source component  73 , the fan  80  and the communication opening  50  overlap with each other when viewed along the left and right direction. 
         [0082]    As shown in  FIGS. 4 and 5 , the fan  80  is disposed on the paper opening  6  side (the upstream side) in the feeding direction X in the lower part  47  of the right plate  51 . As shown in  FIG. 1 , the fan  80  is disposed on the paper opening  6  side (i.e., on the front side) with respect to the paper supply roller  12  and the process cartridge  15 . In other words, the paper supply roller  12  is disposed on the opposite side of the paper opening  6  with respect to the fan  80 . 
         [0083]    As shown in  FIG. 5 , the fan  80  is disposed on the right side of the right paper restriction part  60  to have an interval therebetweem, and faces the right paper restriction part  60  via the communication opening  50 . 
         [0084]    The size of the fan  80  in the up and down direction is substantially equal to the size in the up and down direction of the lower part  47  of the plate  51 . The upper edge of the fan  80  is higher than the upper edge of the right paper restriction part  60 . 
         [0085]    The fan  80  includes a rotating wing  81 . The rotating wing  81  is rotatably provided with respect to the plate  51 . By rotating, the rotating wing  81  causes air in the enclosure  54  to flow from the right side to the left side. Although not shown in the drawings, the fan  80  is electrically connected to the substrate main body  72  via wiring. 
         [0086]    4. Sheet Storing Operation and Image Formation Operation 
         [0087]    (4-1) Sheet Storing Operation 
         [0088]    In the printer  1  configured as described above, a worker puts the sheet of paper P in the paper container  9  before the image formation operation as shown in  FIG. 4 . To put the sheet of paper P in the paper container  9 , the worker moves the paper cover  8  to the opened position so as to open the paper opening  6  in the front and rear direction. 
         [0089]    Then, the worker introduces the sheet of paper P into the paper container  9  along the feeding direction X pointing from the front side to the rear side via the paper opening  6 . At this time, the first restriction plate  62  of the paper restriction part  60  restricts movement of the sheet of paper P in the left and right direction, and the second restriction plate  63  restricts the number of sheets of paper P introduced into the paper container  9 . 
         [0090]    As a result, the rear parts of the sheets of paper P are supported at the paper container  9 , and are stacked on the upper surface of the bottom wall  42 . Thus, a predetermined number of sheets of paper P is supported by the bottom wall  42  and the paper supply cover  8 . In this case, the lower parts  47  of the pair of plates  51  are disposed to have an interval in the left and right direction with respect to the sheets of paper P supported by the bottom wall  42 . 
         [0091]    (4-2) Development Operation 
         [0092]    Next, when the image formation operation is started under control of the control unit  70 , the low voltage power source board  71  supplies power from the power source component  73  to the scorotron charger  22 , the transfer roller  21 , the development roller  25  and the supply roller  26 . The motor (not shown) inputs the driving force to the various rollers (specifically, the photosensitive drum  20 , the development roller  25 , the supply roller  26 , the agitator  30 , the pickup roller  11 , the paper supply roller  12  and the pressure roller  32 ) via the gear train. 
         [0093]    Then, the scorotron charger  22  charges the surface of the photosensitive drum  20  uniformly. Thereafter, the scanner unit  16  exposes the surface of the photosensitive drum  20 . As a result, an electrostatic latent image based on image data is formed on the surface of the photosensitive drum  20 . 
         [0094]    The agitator  30  agitates the toner in the toner reservoir  28 , and supplies the agitated toner to the supply roller  26 . The supply roller  26  supplies the toner supplied from the agitator  30  to the development roller  25 . At this time, the toner is frictionally charged positively between the development roller  25  and the supply roller  26 , and is held on the development roller  25 . The layer thickness limiting blade  27  restricts the thickness of the toner held on the development roller  25  to a predetermined thickness. 
         [0095]    The development roller  25  supplies, the toner which is held thereon to have a constant thickness, to the electrostatic latent image on the surface of the photosensitive drum  20 . As a result, a toner image is held on the surface of the photo sensitive drum  20 . 
         [0096]    (4-3) Paper Supply Operation, Fixing Operation and Discharge Operation 
         [0097]    The pickup roller  11  sends out the sheet of paper P supported at the paper container  9  toward the space between the paper supply roller  12  and the paper supply pad  13 . The paper supply roller  12  handles, one by one, the sheet of paper P supplied to the space between the paper supply roller  12  and the paper supply pad  13 . Then, the paper supply roller  12  conveys one by one the sheet of paper P to the rear side, and thereby the paper supply roller  12  conveys the sheet of paper P to the paper supply path  14  extending in the up and down direction. The sheet of paper P is supplied to the space between the photosensitive drum  20  and the transfer roller  21  at predetermined timing. That is, the paper supply roller  12  conveys the sheet of paper P supported at the paper container  9  to the process cartridge  15 . 
         [0098]    Next, when the sheet of paper P passes through the space between the photosensitive drum  20  and the transfer roller  21 , the transfer roller  21  transfers the toner image on the photosensitive drum  20  to the sheet of paper P through a transfer bias. 
         [0099]    Thereafter, the sheet of paper P is conveyed to the space between the heat roller  31  and the pressure roller  32 . Then, the heat roller  31  and the pressure roller  32  heats and pressurize the sheet of paper P when the sheet of paper P passes through the space between the heat roller  31  and the pressure roller  32 . At this time, the toner image on the sheet of paper P is thermally foxed on the sheet of paper P. Thereafter, the sheet of paper P is conveyed to the space between a pair of discharge rollers  36 , and the pair of discharge rollers  36  discharges the sheet of paper P to the paper discharge tray  35  of the top cover  7 . 
         [0100]    Thus, the sheet of paper P is supplied from the paper container  9 , passes through the space between the photosensitive drum  20  and the transfer roller  21 , and then passes through the space between the heat roller  31  and the pressure roller  23 . Then, the sheet of paper P is conveyed along a conveying path formed in a shape of a letter C when viewed as a side view so that the sheet of paper P is discharged to the paper discharge tray  35 . 
         [0101]    5. Cooling Operation 
         [0102]    In the above described image formation operation, the power source component  73  supplies power to the scorotron charger  22 , the transfer roller  21 , the development roller  25  and the supply roller  26 . Therefore, the power source component  73  may generate heat. The power source component  73  also supplies power to the fan  80  during the image formation operation. Therefore, the rotating wing  81  is continuously driven as shown in  FIG. 5 . 
         [0103]    As a result, air around the fan  80  in the enclosure  54  is discharged into the paper container  9  via the communication opening  50 . In this case, air in the enclosure  54  flows toward the fan  80 , and the pressure in the enclosure  54  decreases. As a result, outside air is taken into the enclosure  54  via the ventilation hole  55  as shown in  FIG. 3 . 
         [0104]    Consequently, an air current A from the ventilation hole  55  to the fan  80  is generated in the enclosure  54 . That is, the air current A proceeds from the upper rear side to the lower front side. 
         [0105]    As shown in  FIG. 5 , when the air current A reaches the low voltage power source board  71 , the air current A branches into an air current Al passing through the left side of the substrate main body  72  and an air current A 2  passing through the right side of the substrate main body  72 . 
         [0106]    After the air current Al passes through, toward the lower rear side, the space above the power source component  73  and between the substrate main body  72  and the plate  51 , the air current Al reaches the power source component  73  and proceeds along the circumferential surface of the upper part of the power source component  73 . Thereafter, the air current Al proceeds toward the fan  80 . 
         [0107]    After the air current A 2  passes through the space between the substrate main body  72  and the side cover  46  toward the lower rear side, the air current A 2  passes through the gap between the lower edge of the substrate main body  72  and the lower edge of the peripheral wall  52  while making a U-turn and then the air current A 2  reaches the portion under the power source substrate  73 . Then, the air current A 2  proceeds along the circumferential surface of the lower part of the power source component  73 , and thereafter proceeds to the fan  80 . Although not shown in the drawings, the air current A 1  and the air current A 2  also pass through the front and rear sides of the power source component  73 . 
         [0108]    Then, the air current Al and the air current A 2  join together, and flow into the paper container  9  via the communication opening  50  while being driven by the fan  80 . That is, the fan  80  serves as an air discharging fan for discharging air to the paper container  9 . 
         [0109]    As a result, the low voltage power source board  71 , namely the power source component  73 , is cooled by the air current A (i.e., the air current A 1  and the air current A 2 ) during the image formation. 
         [0110]    As shown in  FIG. 2 , the air current A which has flowed into the paper container  9  proceeds to the left side in the front edge part of the paper container space S 1 , and proceeds frontward to the paper opening  6  because the paper opening  6  is opened. Then, the air current A is discharged to the outside via the paper opening  6 . 
         [0111]    Thus, the cooling operation for the low voltage power source board  71  is completed. 
         [0112]    6. Advantageous Effects 
         [0113]    (1) As shown in  FIG. 4 , in the printer  1 , the paper container  9  supports the rear part of the sheet of paper P. That is, in the paper container  9 , the paper container space S 1  for supporting the sheet of paper P is secured. Further, as shown in  FIG. 5 , the fan  80  is disposed on the lower part  47  of the plate  51  defining the paper container  9 . 
         [0114]    Therefore, as shown in  FIG. 4 , a flowing path for the air being flowed by the fan  80  can be secured in the paper container space S 1  in the paper container  9 . As shown in  FIGS. 4 and 5 , the fan  80  is disposed on the side on which the paper opening  6  is provided in the feeding direction X, i.e., on the front edge part of the lower part  47  of the plate  51 . 
         [0115]    Therefore, the air in the paper container  9  can be smoothly discharged via the paper opening  6  through driving by the fan  80 . As a result, even when an object is installed next to the printer  1 , smooth flowing of air in the body casing  2  can be secured, and therefore heat in the printer  1  can be effectively radiated. Accordingly, the degree of freedom in regard to an installation position of the printer  1  can be enhanced. 
         [0116]    (2) As shown in  FIG. 5 , the low voltage power source board  71  is supported by the plate  51  on which the fan  80  is disposed. Therefore, the fan  80  is disposed close to the power source component  73 . As a result, by driving the fan  80 , the air around the power source component  73  can be securely flowed, and thereby the power source component  73  can be cooled effectively. 
         [0117]    (3) As shown in  FIG. 1 , the process cartridge  15 , the fixing unit  17  and the paper supply roller  12  are disposed at positions which are overlap with each other when viewed along the up and down direction. Therefore, the size of the printer  1  in the front and rear direction can be downsized in comparison with the case where the process cartridge  15 , the fixing unit  17  and the paper supply roller  12  are aligned in the front and rear direction. As a result, the degree of freedom in regard to the installation position of the printer  1  can be enhanced. 
         [0118]    Further, the process cartridge  15 , the fixing unit  17  and the paper supply roller  12  are disposed on an opposite side (specifically on the rear side) of the paper opening  6  with respect to the fan  80 . Therefore, the process cartridge  15 , the fixing unit  17  and the paper supply roller  12  are disposed to have an interval with respect to the paper opening  6  in the front and rear direction. 
         [0119]    As a result, it becomes possible to prevent air heated by heat generation of the power source component  73  from flowing toward the process cartridge  15 , the fixing unit  17  and the paper supply roller  12  by driving of the fan  80 , and thereby it becomes possible to prevent the process cartridge  15 , the fixing unit  17  and the paper supply roller  12  from being heated. 
         [0120]    The fan  80  is disposed on the front edge part of the lower part  47  of the plate  51 , and discharges the air toward the paper container  9 . Therefore, the air discharged to the paper container  9  by the fan  80  tends to be discharged to the outside of the paper container  9  via the paper opening  6  rather than flowing toward the side on which the process cartridge  15  is disposed. Therefore, it is securely prevented that the air heated by heat radiation of the power source component  73  heats the process cartridge  15 , the fixing unit  17  and the paper supply roller  12 . 
         [0121]    (4) As shown in  FIG. 1 , the paper supply roller  12  is disposed on the lower side with respect to the upper edge  90  of the paper opening  6 . Therefore, a relatively large space can be secured in the paper container  9  on a side on which the paper opening  6  is disposed with respect to the paper supply roller  12 . As a result, by driving of the fan  80 , the air in the paper container  9  can be discharged securely. 
         [0122]    (5) As shown in  FIG. 1 , in the state where the process cartridge  15  is attached to the body casing  2 , the lower edge part  91  of the process cartridge  15  is disposed on the lower side of the upper edge  90  of the paper opening  6 . 
         [0123]    Therefore, in the paper container  9 , a relatively large space can be secured in the paper container  9  on a side on which the paper opening  6  is disposed with respect to the process cartridge  15 , i.e., the paper supply roller  12 . As a result, by driving of the fan  80 , the air in the paper container  9  can be discharged more securely. 
         [0124]    (6) As shown in  FIG. 3 , the body casing  2  has the ventilation hole  55 . Therefore, when the fan  80  is driven, outside air flows into the enclosure  54  via the ventilation hole  55 . As a result, the air current A can be generated between the ventilation hole  55  and the fan  80  in the enclosure  54 . 
         [0125]    As shown in  FIG. 1 , the ventilation hole  55  is disposed on the upper side with respect to the process cartridge  15  and is disposed to be aligned with the process cartridge  15  in the up and down direction when viewed along the left and right direction. That is, the ventilation hole  55  and the fan  80  are disposed to have a sufficient space therebetween along a direction connecting the lower front side and the upper rear side. 
         [0126]    Therefore, as shown in  FIG. 3 , an adequate flowing space for the air current A generated between the ventilation hole  80  and the fan  80  can be secured, and thereby it becomes possible to let the air current A flow near the power source component  73 . As a result, it becomes possible to cool the power source component  73  more effectively. 
         [0127]    (7) As shown in  FIG. 5 , the power source component  73  and the fan  80  overlap with each other when viewed along the left and right direction. Therefore, by driving of the fan  80 , it becomes possible to cause the air around the power source component  73  to flow more securely. As a result, the power source component  73  can be cooled more effectively. 
         [0128]    (8) As shown in  FIG. 5 , the right main frame  45 R and the right side cover  46 R constitute the enclosure  54  which defines the container space S 2 . When the fan  80  is driven, the air current A is generated in the container space S 2 . 
         [0129]    That is, the flowing path of air being caused to flow by the fan  80  can be secured on the paper container  90  side with respect to the fan  80  and on the both sides (left and right sides) of the low voltage power source board  71 . That is, on the left side of the fan  80 , the paper container space S 1  is secured, and on the right side of the fan  80 , the container space S 2  is secured. Therefore, more smooth air flow can be secured in the body casing  2 . 
         [0130]    Since the fan  80  and the low voltage power source board  71  are accommodated in the container space S 2 , it is possible to cause the air current A generated by driving of the fan  80  to pass through a position near the power source component  73  more securely, and thereby it becomes possible to cool the power source component  73  more securely. 
         [0131]    (9) As shown in  FIG. 4 , the pair of paper restriction parts  60  is able to restrict movement of the sheet of paper P in the left and right direction. Therefore, it is possible to prevent an image formed on the sheet of paper P from shifting in the left and right direction during the image formation operation. 
         [0132]    As shown in  FIG. 5 , the fan  80  is disposed to face the right paper restriction part  60  to have an interval therebetween in the left and right direction. Therefore, it is possible to prevent the air current A generated by driving of the fan  80  from causing the sheet of paper P supported by the bottom wall  42  to flop, and thereby it becomes possible to support the sheet of paper P stably. 
         [0133]    (10) As shown in  FIG. 5 , the upper edge of the lower part  47  of the plate  51  is disposed on the upper side with respect to the upper edge of the right paper restriction part  60 . Therefore, as shown in  FIG. 4 , even when the sheet of paper P is accommodated in the paper container  9 , the flowing path of the are being flowed by the fan  80  can be secured in the paper container  9 . 
         [0134]    As shown in  FIG. 5 , the upper edge of the fan  80  is disposed on the upper side with respect to the upper edge of the right paper restriction part  60 . Therefore, it is possible to securely cause the air on the upper side of the sheet of paper P to flow. 
         [0135]    (11) As shown in  FIG. 4 , in the state where the paper supply cover  8  is at the opened position, the paper supply cover  8  supports the front part of the sheet of paper P supported by the bottom wall  42 . Therefore, the paper supply cover  8  and the bottom wall  42  are able to securely support the sheet of paper P. 
         [0136]      7 . Variation 
         [0137]    In the above described embodiment, as shown in  FIG. 5 , the fan  80  causes air to flow from the right side toward the left side and thereby discharges the air toward the paper container  9 . The embodiment is not limited to such a configuration. The fan  80  may cause the air to flow from the left side to the right side and suck the air from the paper container  9 . 
         [0138]    In this case, when the fan  80  is driven, the air disposed on the left side of the communication opening  50  flows toward the right side, and flows from the paper container  9  into the enclosure  54  via the communication opening  50 . Then, the air disposed in the front end part of the paper container space S 1  flows leftward to the fan  80 . Accordingly, the outside air flows into the paper container  9  via the paper opening  6 . 
         [0139]    On the other hand, since the air flows from the paper container  9  into the enclosure  54 , pressure in the enclosure  54  increases and thereby the air in the enclosure  54  is discharged to the outside through the ventilation hole  55 . 
         [0140]    Accordingly, in the enclosure  54 , an air current flowing from the fan  80  to the ventilation hole  55  is generated. At this time, the air current proceeds from the lower front side to the upper rear side. 
         [0141]    In the variation of the above described type, an air current is generated in the enclosure  54 , and the air current passes through positions near the low voltage power source board  71  and the power source component  73 . Therefore, the same advantageous effects as those of the above described embodiment can also be achieved.