Abstract:
An aerator includes: a ventilating member that is disposed opposedly to a heat generating object, and that allows air to flow through an inside; and an inlet device that takes in air from an outside, and that sends the air to the ventilating member, the ventilating member including: a discharging portion that discharges the air flowing through the ventilating member to the outside; an opening through which heat generated by the heat generating object is taken in the ventilating member; and a restraining portion that restrains the air taken in by the inlet device from flowing to the heat generating object through the opening.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is based on and claims priority under 35 U.S.C. 119 from Japanese Patent Application No. 2007-049573 filed Feb. 28, 2007. 
       BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present invention relates to an aerator and an image forming apparatus. 
         [0004]    2. Related Art 
         [0005]    There is a known image forming apparatus comprising: a fixing unit which is disposed in the body of the image forming apparatus, and through which a recording medium after an image formed on an image carrier is transferred is passed, whereby the transferred image on the recording medium is heated and fixed; a ventilating duct which is disposed between the fixing unit and another image forming unit disposed in the apparatus body, with forming a heat discharging hole on the side of the fixing unit; and an aerating fan which sucks air from the heat discharging hole to send the air to the inside of the ventilating duct. 
       SUMMARY 
       [0006]    According to an aspect of the present invention, an aerator includes: a ventilating member that is disposed opposedly to a heat generating object, and that allows air to flow through an inside; and an inlet device that takes in air from an outside, and that sends the air to the ventilating member, the ventilating member including: a discharging portion that discharges the air flowing through the ventilating member to the outside; an opening through which heat generated by the heat generating object is taken in the ventilating member; and a restraining portion that restrains the air taken in by the inlet device from flowing to the heat generating object through the opening. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    Exemplary embodiment of the present invention will be described in detail based on the following figures, wherein: 
           [0008]      FIG. 1  is a side view schematically showing the configuration of an image forming apparatus of a first embodiment of the invention; 
           [0009]      FIG. 2  is an exploded perspective view showing a duct used in the first embodiment of the invention; 
           [0010]      FIG. 3  is a section view showing the duct used in the first embodiment of the invention taken along a line A-A in  FIG. 1 ; 
           [0011]      FIG. 4  is a perspective view showing a wall used in the first embodiment of the invention; 
           [0012]      FIG. 5  is a perspective view showing a modification of the wall used in the first embodiment of the invention; 
           [0013]      FIG. 6  is a block diagram showing a control portion used in the first embodiment of the invention; 
           [0014]      FIG. 7  is a flowchart illustrating the operation of a fixing device and an inlet device used in the first embodiment of the invention; 
           [0015]      FIG. 8  is a perspective view showing a moving member used in a second embodiment of the invention; 
           [0016]      FIGS. 9A and 9B  are section views showing the state of the moving member used in the second embodiment of the invention, wherein  FIG. 9A  is a section view showing the state of the moving member used in the second embodiment of the invention, in the case where the inlet device is operated, and  FIG. 9(   b ) is a section view showing the state of the moving member in the case where the inlet device is stopped; 
           [0017]      FIG. 10  is a perspective view showing an opening formed in a partition member used in a third embodiment of the invention; 
           [0018]      FIG. 11  is a perspective view showing an opening formed in a partition member used in a fourth embodiment of the invention; 
           [0019]      FIG. 12  is an exploded perspective view illustrating a configuration in which a duct is formed in a fifth embodiment of the invention; 
           [0020]      FIG. 13  is an exploded perspective view illustrating a configuration in which a duct is formed in a sixth embodiment of the invention; and 
           [0021]      FIG. 14  is a section view showing a ventilating path used in the sixth embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    Next, embodiments of the invention will be described with reference to the accompanying drawings. 
         [0023]      FIG. 1  shows an image forming apparatus  10  of an embodiment of the invention. The image forming apparatus  10  has an image forming apparatus body  12 . In the image forming apparatus body  12 , a sheet supplying device  14 , an image forming portion  15 , a power supply unit  34 , a control unit  36 , and a fixing device  30  used as a heat generating object are mounted, and a conveyor path  19  for conveying a sheet used as a recording medium is formed. In the image forming apparatus body  12 , a discharge port  13  is formed. An upper portion of the image forming apparatus body  12  is used as a sheet discharge portion  16  to which a sheet that has undergone an image forming process is discharged. 
         [0024]    The image forming portion  15  has a photosensitive member unit  26  used as an image forming unit, an optical writing device  56 , and a transfer unit  28 , and is used for forming a developer image on a sheet. The photosensitive member unit  26  is detachably attached in the image forming apparatus body  12 , and provided with a photosensitive member unit body  38 . In the photosensitive member unit body  38 , for example, four subunits  50  are disposed in such a manner that they can be attached to and detached from the photosensitive member unit body  38 . 
         [0025]    Each of the subunits  50  has a photosensitive member  40  used as an image carrier. Around the photosensitive member  40 , disposed are: a charging device  42  comprising a charging roll which uniformly charges the photosensitive member  40 , and which is used as charging means; a developing device  44  which develops a latent image written on the photosensitive member  40  by a developer (a toner), and which is used as developing means; a discharging device  46  used as discharging means for discharging the photosensitive member  40  by irradiating the photosensitive member  40  with light after the transfer of the developer image; and a cleaning device  48  which removes a developer remaining on the photosensitive member  40  after the transfer, and which is used as developer removing means. 
         [0026]    The four subunits  50  are used for respectively forming a yellow developer image, a magenta developer image, a cyan developer image, and a black developer image, in the order from the upstream of the sheet conveying direction, i.e., from the lower portion in the gravity direction. The subunits form a yellow developer image, a magenta developer image, a cyan developer image, and a black developer image, on the surfaces of the photosensitive members  40 , respectively. 
         [0027]    Each of the optical writing devices  56  is configured by a laser exposing device. The optical writing devices are arranged on the back side of the photosensitive member unit  26  and in positions corresponding to the photosensitive members  40 , respectively, and irradiate the photosensitive members  40  which are uniformly charged, with laser light, thereby forming latent images. 
         [0028]    The transfer unit  28  is positioned on a front side of the photosensitive member unit  26  (on the left side of  FIG. 1 ), and disposed opposedly to the photosensitive member unit  26 . The transfer unit  28  has two supporting rolls  58 ,  58  which are vertically arranged, and a conveyor belt  60  is looped around the two supporting rolls  58 ,  58 . At least one of the two supporting rolls  58 ,  58  is used as a driving roll for transmitting a driving force to the conveyor belt  60 . In response to the driving transmission from the driving roll, the conveyor belt  60  is rotated. 
         [0029]    The transfer unit  28  has four transfer rolls  62  which are disposed so as to be opposed to the photosensitive members  40  across the conveyor belt  60 . Transfer biases are applied to the transfer rolls  62 , respectively, thereby transferring the developer images formed on the photosensitive members  40  to the sheet. 
         [0030]    The fixing device  30  has a heat roll  70 , and a pressure roll  72  which is in pressure contact with the heat roll  70 . The fixing device is used for fixing the images (developer images) which are transferred onto the sheet by the transfer rolls  62 , by heating and pressurizing the images in a portion where the heat roll  70  is in contact with the pressure roll  72 . 
         [0031]    The sheet supplying device  14  has a sheet container  18 . In the sheet container  18 , sheets are stackingly stored. In one upper end portion of the sheet container  18 , a feed roll  20  is disposed, and a separation roll  22  is disposed opposedly to the feed roll  20 . A sheet which is in the top in the sheet container  18  is picked up by the feed roll  20 , and the sheet is separated and transported by the cooperation of the feed roll  20  and the separation roll  22 . 
         [0032]    The conveyor path  19  is a sheet path extending from the sheet container  18  to the sheet discharge portion  16 . Along the conveyor path  19 , in the order from the lower side in the gravity direction, i.e., from the upstream in the sheet conveying direction to the upper side in the gravity direction, i.e., to the downstream in the sheet conveying direction, the feed roll  20 , the separation roll  22 , a registration roll  24 , the transfer unit  28 , the fixing device  30 , and sheet discharge rolls  32  used as a sheet discharge device are disposed. The resist roll  24  temporarily stops the leading end of the sheet, and then starts the conveyance of the sheet to the downstream in synchronization with the timing of the forming of the developer images in the photosensitive member unit  26 . The sheet discharge rolls  32  transport and discharge the sheet on which the developer images are fixed by the fixing device  30 , to the sheet discharge portion  16  via the discharge port  13 . 
         [0033]    In the image forming apparatus body  12 , an aerator  78  is disposed in a position above the fixing device  30  and between the image forming apparatus body  12  and the fixing device  30 . The aerator  78  has a duct  76  used as a ventilating member, and an inlet device which will be described later. The aerator is used for intaking heat generated by the fixing device  30  into the duct  76  through a space  80  on the side where the fixing device is disposed, and then discharging the heat taken in the duct  76  to the outside. The aerator  78  and the duct  76  will be described later in detail. 
         [0034]    In the thus configured image forming apparatus  10 , the photo sensitive member  40  is uniformly charged by the charging device  42 , and a latent image is formed on the uniformly-charged photosensitive member  40  by the optical writing device  56 . The latent image is visualized with the developer by the developing device  44 , thereby forming a developer image. The developer images formed on the photosensitive members  40  are sequentially transferred to the sheet in the order from the developer image formed on the photosensitive member  40  positioned below, by the transfer rolls  62  of the transfer unit  28 . Then, the developer images transferred to the sheet are fixed to the sheet by the fixing device  30 . 
         [0035]      FIGS. 2 and 3  show the aerator  78 .  FIG. 2  is an exploded perspective view of the aerator  78 , and  FIG. 3  is a section view of the aerator  78 . The aerator  78  has the duct  76  used as the ventilating member, and an inlet device  90  connected to the duct  76 . The duct  76  is disposed opposedly to the fixing device  30 , and enclosed so as to allow air to flow through the inside, and a space is formed inside the duct. The duct  76  is formed by fitting a plate-like member  79  in a downward opening of an upper cover  12   a  which is a part of the image forming apparatus body  12 . The duct is formed so as to extend from the side of the right side face of the image forming apparatus  10  (the front side in  FIG. 1 ) to the side of the left side face of the image forming apparatus  10  (the back side in  FIG. 1 ) along the axial direction of the heat roll  70  and the pressure roll  72 . It is a matter of course that the downward opening of the upper cover  12   a  and the plate-like member  79  can be disposed in close contact with each other so as to form a cylindrical duct  76 . Alternatively, they may be disposed not closely in contact with each other but disposed opposedly, so as to form a duct  76  in which a slight gap exists around the plate-like member  79 . 
         [0036]    The duct  76  has a discharge opening  88  used as a discharge port. For example, the discharge opening  88  is formed in a position on the side of the left side face of the image forming apparatus  10  in the upper face of the upper cover  12   a . The discharge opening is used for discharging the air in the duct  76  to the outside of the duct  76 , and for discharging the air to the outside of the image forming apparatus body  12 . 
         [0037]    The inlet device  90  is connected to the duct  76  so as to be attached to, for example, the right side of the plate-like member  79 , and used for intaking air from the outside of the duct  76  into the duct  76 , and for sending the air taken in the duct  76  through the duct  76 . When the inlet device  90  is driven, and the intake of air into the duct  76  is performed, an air flow from the inlet device  90  to the discharge opening  88  is produced, as shown by the arrows in  FIG. 3 . Then, due to the air flow, the upper cover  12   a  heated by the heat generated by the heat roll  70  of the fixing device  30  is cooled. 
         [0038]    On the left side of the position of the plate-like member  79  where the inlet device  90  is attached, a slope  92  which is higher as more advancing from the right side to the left side is formed. The slope  92  is used as a restraining portion and also used as a guide plane. The slope guides the air taken in by the inlet device  90  to the side opposite to the fixing device  30 , i.e., to the upper side. Since the air is guided upwards by the slope  92 , the air stream is hit on the upper portion of the upper cover  12   a . Thus, the upper portion of the upper cover  12   a  is cooled by the air stream. 
         [0039]    The duct  76  has an opening  94 . The opening  94  is used for intaking the heat generated by the fixing device into the duct  76 . For example, a plurality of openings  94  are formed in the plate-like member  79 . Each opening  94  has a substantially circular shape, for example, for communicating the inside of the duct  76  with the space  80  (see  FIG. 1 ) on the side where the fixing device  30  is disposed. In the case where the openings  94  are not formed, the space  80  and the inside of the duct  76  are not communicated with each other, so that the heat generated by the heat roll  70  is hardly moved to the inside of the duct  76 . Thus, the heat generated by the heat roll  70  stays in the space  80 , and there is a possibility that the heat release from the fixing device  30  is not well performed. In the embodiment, the heat generated by the fixing device  30  is moved to the inside of the duct  76  via the openings  94 . 
         [0040]    The duct  76  has walls  96  used as restraining portions (see  FIG. 3 ). The walls  96  are formed so as to be respectively around the openings  94  raised from the plate-like member  79  in the duct  76 . For example, the walls are formed on the side of the inlet device  90  which is the upstream side of the air flow with respect to the respective openings  94 . In  FIG. 2 , the openings  94  will be hidden in the figure, and therefore the walls  96  are omitted in the figure. 
         [0041]      FIG. 4  is an enlarged view showing one of the walls  96 . For example, the number of the walls  96  is the same as that of the openings  94 . In the case where the walls  96  are not disposed, there is a possibility that the air taken into the duct  76  by the inlet device  90  easily flows to the side of the fixing device  30  from the inside of the duct  76  via the openings  94 . When the air flows from the inside of the duct  76  to the side of the fixing device  30 , this air flow causes heat generated by the fixing device  30  to be hardly moved into the duct  76 . 
         [0042]    In the embodiment, as shown by the arrows of  FIG. 4 , the air flows to the openings  94  are blocked by the walls  96 , and the directions thereof are changed, so that the air flows pass around the sides of the openings  94 . As shown by the arrows in  FIG. 4 , the heat is moved from the side of the fixing device  30  to the side of the duct  76  via the openings  94 , in such a manner that, for example, the heated air is moved upwards. 
         [0043]      FIG. 5  shows a modification of the wall  96 . In the modification, walls  96   a ,  96   a  are formed so as to be inclined with respect to the air-flow direction in the duct  76 . In the duct  76 , as shown by the arrows in  FIG. 5 , the air flows in a direction separating from the opening  94  along the walls  96   a ,  96   a.    
         [0044]      FIG. 6  shows the control unit  36 . 
         [0045]    The control unit  36  has a control circuit  100  used as a control portion. Image data are input into the control circuit  100  via a communication interface  102 . The image forming portion  15 , the fixing device  30 , and the inlet device  90  are controlled by the output from the control circuit  100 . 
         [0046]      FIG. 7  shows a control flow of the control unit  36 . 
         [0047]    First, it is checked in step S 10  whether the driving of the inlet device  90  is in an OFF state or not. If it is checked that the inlet device  90  is in the OFF state, the control circuit  100  controls in next step S 14  the image forming portion  15  to perform image forming on a sheet (forming of a developer image), and controls the fixing device  30  to fix the image (developer image) formed on the sheet by the image forming portion  15 , onto the sheet. In the embodiment, the fixing device  30  is driven in a state where the inlet device  90  is stopped, so that, during the driving of the fixing device  30 , the heat generated by the fixing device  30  can be moved to the duct  76  without being impeded by the air flow generated by the inlet device  90 . 
         [0048]    When it is checked in next step S 18  that the sheet on which an image is formed is the last sheet in this series of image forming operations, it is checked in next step S 22  whether the fixing device  30  is in the OFF state or not. After it is checked that the fixing device is in the OFF state, the control circuit  100  starts in step S 26  the driving of the inlet device  90 , thereby starting the intake of air into the duct  76 . In the embodiment, in response to the stopping of the fixing device  30 , the control circuit  100  starts the driving of the inlet device  90 . Even when a state where the upper cover  12   a  is heated by the heat from the fixing device  30  occurs, therefore, the upper cover  12   a  is cooled by the air which is taken by the inlet device  90  and discharged from the discharge opening  88 , after the fixing device  30  is stopped. 
         [0049]    After it is checked in next step S 30  that a predetermined time elapses from the start of the driving of the inlet device  90 , the control circuit  100  stops the inlet device  90 , thereby terminating the intake of air. The predetermined time of step S 30  is determined depending on, for example, the number and the size of sheets on which images are formed in step S 14 , and determined as a time period in which the upper cover  12   a  heated in step S 14  by the heat generated by the fixing device  30  is sufficiently cooled. 
         [0050]      FIG. 8  is an enlarged view of a surrounding portion of an opening  94  of an image forming apparatus  10  which is a second embodiment of the invention. In the above-described first embodiment, the wall  96  is disposed in the position on the side of the inlet device  90  with respect to the opening  94  in the duct  76 . By contrast, in the second embodiment, a moving member  110  used as a restraining portion and as a moving portion is disposed in a position on the side of the inlet device  90  with respect to the opening  94  in the duct  76 . 
         [0051]    The moving member  110  is made of a flexible and elastic material such as a PET film, and, for example, configured as a plate-like member. One end portion  110   a  of the moving member is fixed to a position of the plate-like member  79  on the side of the inlet device  90  with respect to the opening  94 . The other end portion  110   b  is extended in a direction above the opening  94  in, for example, a bent manner. 
         [0052]      FIG. 9  illustrates the operation of the moving member  110  in the invention. 
         [0053]    In a state where the intake of air is not performed by the inlet device  90 , as shown in  FIG. 9(   b ), the other end portion  110   b  is located in a position for opening the opening  94 . When, in this state, the driving of the inlet device  90  (see  FIG. 2)  is started, the other end portion  110   b  is pushed by the air taken into the duct  76  by the inlet device  90 . As shown in  FIG. 9(   a ), therefore, the other end portion  110   b  is moved in a direction in which the opening  94  is closed. When the intake of air by the inlet device  90  is stopped, the other end portion  110   b  is moved in a direction in which the opening  94  is opened due to the elasticity, and moved to the initial position shown in  FIG. 9(   b ). The second embodiment is identical with the first embodiment except that the moving member  100  is disposed instead of the wall  96 , and therefore the description of the other components is omitted. 
         [0054]      FIG. 10  shows an opening  94  used in a third embodiment of the invention. The openings  94  in the above-described first and second embodiments are substantially circular. In the third embodiment, the opening  94  has a substantially rectangular shape elongated in the air-flow direction. In an edge portion  94   a  of the opening  94  on the downstream side in the air-flow direction, a slope  114  is formed. The slope  114  is higher as more advancing from the right side to the left side, i.e., toward the downstream side of the air-flow direction. Similarly to the above-described slope  92  (see  FIGS. 2 and 3 ), the slope  114  is used as a guide portion for guiding the air taken by the inlet device  90  to the side opposite to the fixing device  30 , i.e., toward the upper side. According to the configuration, as compared with the case where the slope  114  is not disposed, the amount of air flowing from the inside of the duct  76  to the side of the fixing device  30  is reduced. The third embodiment is identical with the above-described first embodiment except the shape of the opening  94  and that of the edge portion of the opening  94 , and therefore the description of the other components is omitted. 
         [0055]      FIG. 11  shows an opening  94  used in a fourth embodiment of the invention. 
         [0056]    In the above-described first and second embodiments, the openings  94  have the substantially circular shape, and, in the above-described third embodiment, the opening  94  has the substantially rectangular shape. By contrast, in the embodiment, the opening  94  has a shape in which the width is gradually decreased toward the downstream side in the air-flow direction. As compared with the case where the opening  94  having a uniform width in the air-flow direction is used, therefore, the amount of air flowing from the duct  76  to the fixing device  30  is reduced on the side of an end portion  94   b  which is on the downstream side of the air-flow direction. In the embodiment, therefore, the circumferential portion of the opening  94  of the plate-like member  79  is used as a changing portion for changing the shape of the opening  94 . 
         [0057]      FIG. 12  shows a duct  76  used in a fifth embodiment of the invention. In the fifth embodiment, similarly to the above-described first embodiment, the duct  76  is formed so as to be surrounded by the image forming apparatus body  12  and the plate-like member  79 . In the duct  76  of the fifth embodiment, a dividing plate  120  which is not disposed in the above-described first to fourth embodiments is disposed. The dividing plate  120  is used as a dividing portion for dividing the space in the duct  76  into a first ventilating path  122  and a second ventilating path  124 . For example, the dividing plate  120  has a flat plate-like shape. A right end portion of the dividing plate  120  is not in contact with a rim portion  79   a  of the plate-like member  79  and a right inner side face of the upper cover  12   a , and a gap G 1  is formed between the right end portion, and the upper cover  12   a  and the rim portion  79   a.    
         [0058]    The first ventilating path  122  is disposed on a front side in the duct  76 , and on the side of the duct  76  where the inlet device  90  and the slope  92  are disposed in the width direction of the duct  76 . The second ventilating path  124  is disposed on the back side of the image forming apparatus  10 , and on a side opposite to the side where the inlet device  90  and the slope  92  are disposed in the width direction of the duct  76 . The amount of air flowing through the second ventilating path  124  is smaller than that flowing through the first ventilating path  122 . Specifically, to the first ventilating path  122 , the air taken by the inlet device  90  is guided along the slope  92  as shown by the arrow a in the figure. By contrast, to the second ventilating path  124 , as shown by the arrow b in the figure, the air only flows while passing around the dividing plate  120  via the gap G 1 . 
         [0059]    In the above-described first embodiment, the openings  94  are formed in a dispersed manner over the entire surface of the plate-like member  79 . By contrast, in the fifth embodiment, the openings  94  are formed on the back side of the plate-like member  79  so as to communicate the inside of the second ventilating path  124  with the space  80  on the side where the fixing device  30  is disposed (see  FIG. 1 ). The openings  94  are not formed on the side of the first ventilating path  122  of the plate-like member  79 . Therefore, the second ventilating path  124  is communicated with the space  80  via the openings  94 , but the first ventilating path  122  is not communicated with the space  80 . 
         [0060]    In the thus configured fifth embodiment, when the driving of the inlet device  90  is started, the air from the inlet device  90  is divided so as to flow into the first ventilating path  122  and the second ventilating path  124 . The air flowing into the first ventilating path  122  flows through the first ventilating path  122  from the right side to the left side, and the air is discharged from the discharge opening  88 . At this time, the air flow in the first ventilating path  122  cools the upper cover  12   a  in which the temperature may be raised by the heat generated by the fixing device  30 . 
         [0061]    The air flowing into the second ventilating path  124  while passing through the gap G 1  flows through the second ventilating path  124  from the right side to the left side, and then discharged from the discharge opening  88 . By means of the air flow in the second ventilating path  124 , the heat generated by the fixing device  30  and moved into the second ventilating path  124  via the openings  94  is discharged to the outside of the image forming apparatus body  12  via the discharge opening  88 . At this time, the amount of air flowing in the second ventilating path  124  is smaller than that in the case where the dividing plate  120  is not disposed, and as compared with the amount of air flowing in the first ventilating path  122 . Accordingly, the air flow of the air heated by the fixing device  30  via the openings  94  is hardly impeded. 
         [0062]    The above-described fifth embodiment may be combined with at least one or more of the above-described first to fourth embodiments. When the fifth embodiment is combined with the first embodiment, for example, the wall  96  (see  FIG. 3 ) may be disposed on the side of the inlet device with respect to the opening  94 , and the dividing plate  120  may be disposed in the duct  76 . The same components as those of the first embodiment are denoted by identical reference numerals, and the description is omitted. 
         [0063]      FIGS. 13 and 14  show a duct  76  which is used in a sixth embodiment of the invention. In the above-described fifth embodiment, the dividing plate  120  is disposed in a substantially vertical direction in the duct  76 , and the first ventilating path  122  is formed on the front side and the second ventilating path  124  is formed on the back side. By contrast, in the sixth embodiment, a dividing plate  120  is disposed substantially horizontally in the duct  76 . A first ventilating path  122  is formed on the upper side, i.e., on the side of the upper cover  12   a , and a second ventilating path  124  is formed on the lower side, i.e., on the side of the fixing device  30 . 
         [0064]    For example, the dividing plate  120  is disposed in the upper cover  12   a  with being supported by a front inner side face and a back inner side face. A gap G 2  is formed between a left end portion of the dividing plate and the upper cover  12   a . Via the gap G 2 , the second ventilating path  124  and the first ventilating path  122  are communicated with each other. The dividing plate  120  is disposed in the duct  76  in such a manner that the amount of air flowing through the first ventilating path  122  is larger than that flowing through the second ventilating path  124 . Specifically, a relatively larger part of the air taken by the inlet device  90  is guided along the slope  92  so as to flow into the first ventilating path  122 , and a relatively smaller part of the air taken by the inlet device  90  is caused to flow into the second ventilating path  12  by moving around to the lower side of the dividing plate  120 . 
         [0065]    In the same manner as the fifth embodiment, openings  94  are formed so that the second ventilating path  124  is communicated with the space  80  on the side where the fixing device  30  is disposed. The first ventilating path  122  is not communicated with the space on the side where the fixing device  30  is disposed. 
         [0066]    In the thus configured sixth embodiment, the air flowing through the first ventilating path  122  cools the upper cover  12   a , and the air flowing through the second ventilating path  124  causes the heat generated by the fixing device  30  and moved to the second ventilating path  124  via the openings  94  to be discharged to the outside of the image forming apparatus body  12  via the gap G 2  and the discharge opening  88 . In this case, in the same manner as the above-described fifth embodiment, the amount of air flowing through the second ventilating path  124  is smaller as compared with the case where the dividing plate  120  is not disposed, and than that flowing through the first ventilating path  122 . Accordingly, the air flow of the air heated by the fixing device  30  via the openings  94  is hardly impeded. 
         [0067]    In the same manner as the fifth embodiment, the sixth embodiment may be combined with at least one or more of the above-described first to fourth embodiments. When the fifth embodiment is combined with the first embodiment, for example, the walls  96  may be disposed on the side of the inlet device of the openings  94 , and the dividing plate  120  may be disposed in the duct  76 . The same portions as those of the first embodiment are denoted by identical reference numerals, and their description is omitted. 
         [0068]    The foregoing description of the embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention defined by the following claims and their equivalents.