Abstract:
A recording material cooling device includes: a transporting section that transports a recording material; a heat radiation section that radiates heat of the recording material through the transporting section, the heat radiation section coming into contact with the transporting section; an air current generating section that generates an air current which flows through the heat radiation section; and a pair of passages that are respectively located before and after a zone where the transporting section and the heat radiation section are brought into contact with each other, each of the pair of passages being formed on an outer side of the heat radiation section to flow a portion of the air current.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2008-244075 filed on Sep. 24, 2008. 
       BACKGROUND 
     Technical Field 
       [0002]    The present invention relates to a recording material cooling device and an image forming apparatus. 
       SUMMARY 
       [0003]    According to an aspect of the invention, there is provided a recording material cooling device including: a transporting section that transports a recording material; a heat radiation section that radiates heat of the recording material through the transporting section, the heat radiation section coming into contact with the transporting section; an air current generating section that generates an air current which flows through the heat radiation section; and a pair of passages that are respectively located before and after a zone where the transporting section and the heat radiation section are brought into contact with each other, each of the pair of passages being formed on an outer side of the heat radiation section to flow a portion of the air current. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]    Exemplary embodiments of the present invention will be described in detail based on the following figures, wherein: 
           [0005]      FIG. 1  is a conceptual diagram illustrating an example of an image forming apparatus utilizing the invention; 
           [0006]      FIG. 2  is a perspective view illustrating an example of a cooling device; 
           [0007]      FIG. 3  is a perspective view illustrating an example of the cooling device; 
           [0008]      FIG. 4  is a perspective view illustrating an example of the cooling device; 
           [0009]      FIGS. 5A and 5B  are perspective views illustrating examples of a configuration for generating turbulence; 
           [0010]      FIG. 6  is a conceptual diagram illustrating an example of the cooling device; 
           [0011]      FIG. 7  is a conceptual diagram illustrating an example of a transport belt; 
           [0012]      FIG. 8  is a conceptual diagram illustrating an example of a control system; 
           [0013]      FIG. 9  is a flowchart illustrating an example of the operation which is executed by the control system; and 
           [0014]      FIG. 10  is a conceptual diagram illustrating an example of the cooling device. 
       
    
    
     DESCRIPTION OF REFERENCE NUMERALS AND SIGNS 
       [0015]      10 : image forming section,  10 Y: image forming unit,  10 M: image forming unit,  10 C: image forming unit,  10 K: image forming unit,  11 : photoconductor drum,  12 : cleaning roll,  13 : exposure unit,  14 : toner supply unit,  15 : transfer roll,  16 : feed roll,  100 : image forming apparatus,  101 : recording material accommodating unit,  102 : printing paper,  103 : transport path,  104 : transport roller mechanism,  105 : heating fixing unit,  107 : cooling device,  201 : heat roll,  202 : pressure roll,  203 : fixing belt,  204 : drive roll,  205 : belt cleaning roll,  401 : transport belt,  402 : transport belt,  403 : heat sink,  404 : drive roll,  405 : tension roll,  406 : pressing roll group,  407 : drive roll,  408 : tension roll,  501 : air duct,  502 : air duct,  503 : outer plate,  504 : outer plate,  505 : passage,  506 : passage,  507 : resin plate,  508 : resin plate,  510 : fan,  511 : fan,  512 : fan,  521 : outer plate,  522 : outer plate,  531 : projection,  541 : projection,  700 : cooling device,  701 : heat sink,  702 : fan,  703 : fan,  704 : fan 
       DETAILED DESCRIPTION 
       [0016]    Hereafter, a description will be given of an embodiment to which the present invention is applied. 
       (Configuration of Image Forming Apparatus) 
       [0017]      FIG. 1  shows an image forming apparatus  100  in accordance with the embodiment. The image forming apparatus  100  has a recording material accommodating unit  101 . In this example, printing paper  102  which is an example of a recording material is accommodated in the recording material accommodating unit  101 . As the recording material, it is also possible to use a resin-made material such as OHP paper other than paper. 
         [0018]    Reference numeral  16  denotes a feed roll which is used as a feeding section in this embodiment. The feed roll  16  feeds the printing paper  102  from the recording material accommodating unit  101  to the downstream side. A transport roller mechanism  104  for transporting the printing paper  102  discharged from the recording material accommodating unit  101  is disposed on the downstream side of the recording material accommodating unit  101 . An image forming section  10 , which is used as an image forming section in this embodiment, is disposed on the downstream side of the transport roller mechanism  104 . The image forming section  10  forms a toner image on the printing paper. It should be noted that the phrase “downstream side” referred to herein means a following process side in the flow of processing when viewed in a time series, whereas the phrase “upstream side” conversely means a preceding process side in the flow of processing. 
         [0019]    A heating fixing unit  105 , which is used as an image forming section in this embodiment, is disposed on the downstream side of the image forming section  10 . The heating fixing unit  105  heats and fixes on the printing paper the toner image formed on the printing paper. A cooling device  107  for cooling the printing paper discharged from the heating fixing unit  105  is disposed on the downstream side of the heating fixing unit  105 . The printing paper cooled in the cooling device  107  is discharged to an unillustrated discharging section. 
       (Configuration of Image Forming Section) 
       [0020]    Hereafter, a description will be given of the configuration of the image forming section  10  shown in  FIG. 10 . The image forming section  10  has four image forming units  10 Y to  10 M for forming toner images of the respective basic colors of Y, M, C, and K on the printing paper. 
         [0021]    Since the basic structures of the image forming units  10 Y to  10 M are identical, a description will be given hereafter of the configuration of the image forming unit  10 Y as representing them. The image forming unit  10 Y has a photoconductor drum  11 . The photoconductor drum  11  rotates in the direction of arrow in the drawing (counterclockwise direction). A cleaning roll  12  for removing the toner remaining on the surface of the photoconductor drum  11  is disposed on the photoconductor drum  11 . The surface of the photoconductor drum lion the downstream side of the cleaning roll  12  (on the counterclockwise rotation side in the drawing) is irradiated, while being scanned, with a laser beam for forming an electrostatic latent image from an exposure unit  13 . It should be noted that a charging unit (not shown) for charging the photoconductor drum  11  is disposed between this portion where exposure is effected and the cleaning roll  12 . 
         [0022]    A toner supply unit  14  for supplying the toner onto the surface of the photoconductor drum  11  subjected to exposure and having a latent image formed thereon is disposed on the downstream side of that portion of the photoconductor drum  11  which is exposed. A transfer roll  15  is disposed on the further downstream side thereof in face-to-face relation to the photoconductor drum  11 . Described above is the configuration of the image forming unit  10 Y. As for the image forming units  10 M to  10 K, their basic structures are also identical except that toners used are different. 
       (Operation of the Image Forming Section) 
       [0023]    Hereafter, a description will be given of the operation of the image forming units  10 Y to  10 K. It should be noted that since the operation of the image forming units  10 Y to  10 K is basically identical except for the colors of the toners, a description will be given herein of the operation of the image forming unit  10 Y as representing them. 
         [0024]    In the state in which the photoconductor drum  11  is rotating in the counterclockwise direction in the drawing, the toner remaining on its surface is removed by the cleaning roll  12 . Further, this portion where the residual toner was removed is subjected to charging with an electrical charge from an unillustrated charger, and this portion is irradiated, while being scanned, with a laser beam from the exposure unit  13 . As this irradiation with the laser beam is carried out, the surface of the photoconductor drum  11  becomes photosensitized in a state corresponding to the pattern of an image to be formed, thereby forming an electrostatic latent image. 
         [0025]    The toner of the Y color is supplied from the toner supply unit  14  is supplied to the portion where this electrostatic latent image has been formed, and the toner of the Y color is adhered to the surface of the photoconductor drum  11  in correspondence with a charge distribution constituting the electrostatic latent image. A toner image of the Y color is thus formed on the photoconductor drum  11 . In tune with the timing of the formation of this toner image, the printing paper discharged from the recording material accommodating unit  101  is fed into a nip between the photoconductor drum  11  and the transfer roll  15 . As the printing paper is pinched therebetween, the toner image on the photoconductor drum  11  is transferred onto the printing paper. The surface of the photoconductor drum  11  where the transfer of the toner image was effected is subjected to cleaning by the cleaning roll  12 . As the above-described operations are repeated, a toner image of the Y color is formed on the printing paper which is transported along a transport path  103 . 
         [0026]    Described above is the operation of forming the toner image of the Y color by the image forming unit  10 Y, and the formation of toner images of the respective basic colors is also carried out by the image forming units  10 M to  10 K by similar operation. Thus, the toner images of the basic colors of Y, M, C, and K are sequentially superposed on the printing paper which is transported along the transport path  103  in the rightward direction in the drawing, thereby forming a color toner image. 
       (Configuration of Heating Fixing Unit) 
       [0027]    Next, a description will be given of the configuration of the heating fixing unit  105 . The heating fixing unit  105  includes a heat roll  201  and a pressure roll  202  opposing the heat roll  201 . The heat roll  201  has a heater in its interior and generates heat. Reference numeral  203  denotes a fixing belt which is stretched between the heat roll  201  and a drive roll  204 . A belt cleaning roll  205  for cleaning the surface of the fixing belt  203  is in contact with the fixing belt  203 . In addition, the fixing belt  203  at its portion which is in contact with the heat roll  201  is in a state of being pressurized by the pressure roll  202 . 
       (Operation of the Heating Fixing Unit) 
       [0028]    Next, a description will be given of the operation of the heating fixing unit  105 . When the drive roll  204  rotates in the counterclockwise direction in the drawing, the fixing belt  203  rotates in the counterclockwise direction. In this process, the printing paper which has been transported along the transport path  103  from the left direction in the drawing is brought into a nip between the fixing belt  203  and the pressure roll  202 . At this juncture, the toner image formed on the printing paper is heated by the fixing belt  203  and is concurrently pressurized. The fixation of the toner image formed on the printing paper is effected as the pressurization during heating is effected. 
       (Configuration of the Cooling Unit) 
       [0029]    Next, a description will be given of the cooling device  107 . As shown in  FIG. 1 , the cooling device  107  includes a transport belt  401  which is used as a transporting section in this embodiment, as well as a transport belt  402  opposing the transport belt  401 . The arrangement provided is such that the transport belt  401  and the transport belt  402  are brought into contact with each other uniformly with respect to the direction perpendicular to the transporting direction of the printing paper such that no such difference between contacting portions and noncontacting portions is created. The transport belt  401  is an example of an endless belt-shaped member, and its surface on the side away from the side which comes into contact with the printing paper is in contact with a heat sink  403  which is used as a heat radiation section in this embodiment. The heat sink is made of a metal (made of aluminum in this example), and is arranged such that a plurality of fins are arranged with gaps, and heat radiation is effected as air flows through the gaps by the action of below-described fans. In a state in which tension is imparted the transport belt  401  by a tension roll  405 , the transport belt  401  is rotated by being driven by a drive roll  404 . 
         [0030]    As for the transport belt  402 , its surface on the side away from the side which is brought into contact with the printing paper is pressed by a pressing roll group  406 , tension is imparted thereto by a tension roll  408 , and the transport belt  402  is rotated by being driven by a drive roll  407 . The pressing roll group  406  causes a plurality of rolls to be pressed upward (in the direction toward the heat sink  403 ) by the repulsive force of springs, to thereby press the transport belt  402  against the transport belt  401  side. 
         [0031]      FIG. 2  is a schematic perspective view illustrating the cooling device  107 , and  FIG. 3  is a perspective view illustrating a state in which cooling fans are removed from the state shown in  FIG. 2 . It should be noted that, in  FIGS. 2 and 3 , the illustration of the mechanism of a drive system including the drive roll  404  shown in  FIG. 1  is omitted. 
         [0032]    The heat sink  403  is shown in  FIGS. 2 and 3 . As shown in  FIG. 2 , fans  510  to  512 , which are examples of an air current generating section, are disposed on the right side (this side in the drawing) of the heat sink  403  in the paper transporting direction. The fans  510  to  512  are axial flow fans, and the illustration of their blades is omitted in the drawing. The fans  510  to  512  suck air from the heat sink  403  side and exhausts the air current to this side in the drawing. It should be noted that the direction of the flow of the air current may be reverse. 
         [0033]    The lower surface of the heat sink  403  is in contact with the transport belt  401  (this arrangement being not shown in  FIG. 2 ). The transport belt  401  in the state of being in contact with the heat sink  403  moves in the direction from left to right in the drawing. Air ducts  501  and  502  are respectively provided on the upstream side and the downstream side of the heat sink  403 . The air ducts  501  and  502  are so structured that outer plates  503  and  504  obtained by bending metal plates into the illustrated shapes are respectively fixed to the heat sink  403 . 
         [0034]    More specifically, in the air duct  501 , a space which is surrounded by the outer plate  503 , the heat sink  403 , and the transport belt  401  serves as a passage  505  which is used as a passage in this embodiment. The passage  505  is disposed on the upstream side of the heat sink  403  in such a manner as to extend in the direction of traversing the transport belt  401  along that edge portion of the heat sink  403  which comes into contact with the transport belt  401 . An edge of the outer plate  503  is not brought into contact with the transport belt  401 , and its gap is closed by a resin plate  507  (a PET film in this example) which is an example of a gap closing member. The resin plate  507  is fixed to the downstream side of the edge of the outer plate  503 . 
         [0035]    In the air duct  502 , a space which is surrounded by the outer plate  504 , the heat sink  403 , and the transport belt  401  serves as a passage  506  which is used as a passage in this embodiment. The passage  506  is disposed on the downstream side of the heat sink  403  in such a manner as to extend in the direction of traversing the transport belt  401  along that edge portion of the heat sink  403  which comes into contact with the transport belt  401 . An edge of the outer plate  504  is not brought into contact with the transport belt  401 , and its gap is closed by a resin plate  508  (a PET film in this example) which is an example of a gap closing member. The resin plate  508  is fixed to the downstream side of the edge of the outer plate  504 . 
         [0036]    The resin plates  507  and  508  are set in a state of being brought into contact with the transport belt  401  in a state in which the resin plates  507  and  508  are curved with a force applied thereto, so as to be structured to prevent the leakage of air current from between the resin plate and the transport belt. In addition, those edge portions of the resin plates  507  and  508  which are brought into contact with the transport belt  401  are each provided with processing (chamfering) into a rounded shape with their corners removed. A measure is thus provided to reduce the load on the transport belt  401  and the occurrence of abrasion powder. 
       (Operation of the Cooling Unit) 
       [0037]    In the configuration shown in  FIG. 1 , the transport belt  401  is first rotated counterclockwise in the drawing to rotate the transport belt  402  in the clockwise direction in the drawing. In this state, the printing paper which has been transported from the heating fixing unit  105  is nipped between the transport belts  401  and  402 , so that the printing paper is transported in the rightward direction in the drawing. 
         [0038]    At this juncture, the printing paper is pressed against the transport belt  401  by the function of the pressing roll group  406 , so that the transport belt  401  is pressed against the heat sink  403 . In consequence, the heat of the printing surface (surface with an image formed thereon) of the printing paper is radiated to the heat sink  403  through the transport belt  401 , so that the printing paper whose temperature has risen by the heat in the heating fixing unit  105  is cooled. The cooled printing paper is discharged from the cooling device  107  in the rightward direction in the drawing. 
         [0039]    In addition, air flows between adjacent fins of the heat sink  403  by the function of the fans  510  to  512  to effect heat radiation from the heat sink  403 . Part of the air current due to the function of the fans  510  to  512  also flows through the passages  505  and  506 . In addition, as the air flows through the interiors of the passages  505  and  506 , portions of the heat sink  403  which come into contact with this air are air-cooled. 
       (Function of Removing Abrasion Powder in Heat Sink) 
       [0040]    In the above-described cooling action, the transport belt  401 , while being pressed against the heat sink  403  and brought into contact with the heat sink  403 , is moved with respect to the heat sink  403 . At this juncture, the surface of the transport belt  401  is rubbed by the edges of the heat sink  403 , and abrasion dust of the transport belt  401  is produced. This abrasion dust is produced on both the upstream-side edge and the downstream-side edge of the heat sink  403 , but the occurrence is more noticeable on the upstream side. 
         [0041]    This abrasion powder is blown away by the air current flowing through the passages  505  and  506  and is sucked by the fans  510  to  512 . It should be noted that air filters for capturing dust and the like are respectively disposed on the exhaust side of the fans  510  to  512 , and the aforementioned abrasion powder is captured by these air filters. 
       (First Modification) 
       [0042]      FIG. 4  is a perspective view illustrating an example of a configuration provided with air ducts different in the structure from those of  FIG. 3 . In  FIG. 4 , portions denoted by the same reference numerals as those in  FIGS. 2 and 3  are identical to the portions described with reference to  FIGS. 2 and 3 . 
         [0043]    In this example, the configuration adopted is such that outer plates  521  and  522  for making up the air ducts  501  and  502  are formed of a resin (e.g., polyacetal), and their edges are brought into contact with the transport belt  401 . In addition, those edge portions of the outer plates  521  and  522  which are bought into contact with the transport belt  401  are formed into shapes in which their corners are rounded by chamfering. The other arrangements are identical to those of the embodiment described with reference to  FIGS. 1 to 3 . 
       (Second Modification) 
       [0044]      FIG. 5A  is a perspective view illustrating an example in which cylindrical projections  531 , which are used as projecting portions in this embodiment, are provided on an inner surface of the passage of the air duct  501 .  FIG. 5B  is a perspective view illustrating an example in which projections  541  having a similar function are provided thereon. In these examples, as the plurality of projections  531  or  541  are arranged, turbulence is caused to occur in the flow of air flowing in the air duct  510  to thereby enhance the removal efficiency of the abrasion powder. The structure of the projections is not limited to the cylindrical shape and may be in another shape such as a plate shape. 
       (Third Modification) 
       [0045]      FIG. 6  shows a modification of the configuration shown in  FIG. 2 .  FIG. 6  shows an example of a case in which the cross-sectional area of the passage is nonuniform.  FIG. 6  corresponds to a top view of a portion shown in  FIG. 2 . FIG.  6  shows a portion of the heat sink  403 , an air duct  601 , the fan  510 , and the transport belt  401 . In this example, a measure is devised in the cross-sectional shape of a passage  602  of the air duct  601 . Namely, the structure adopted is such that the width of the passage  602  (the width of the route along which air flows) is narrow at an inlet portion of the passage  602 , wide in its central portion, and narrow again at its outlet portion. In other words, the structure is such that the cross-sectional area of the passage  602  is narrow at the inlet portion, wide in the central portion, and narrow again at the outlet portion. 
         [0046]    According to the structure shown in  FIG. 6 , the flow rate in the vicinities of the inlet portion and the outlet portion of the passage  602  is higher in comparison with the flow rate in the central portion. The occurrence of abrasion powder is greater at both ends in the widthwise direction of the transport belt than at the central portion. Accordingly, by making the flow rate in the vicinities of the inlet portion and the outlet portion of the passage  602  higher than at the central portion, the removal of abrasion powder by blowing away can be effected more efficiently than in the case which is not provided with this arrangement. 
       (Fourth Modification) 
       [0047]    Next, a description will be given of a case in which a projecting portion is provided on that surface of the transport belt  401  which comes into contact with the heat sink  403 .  FIG. 7  is a conceptual diagram illustrating an example of the configuration of the transport belt.  FIG. 7  shows a transport belt  543  which can be used instead of the transport belt  401  shown in  FIGS. 1 and 2 . 
         [0048]    A projection  542 , which extends in the widthwise direction of the transport belt  543  and is used as a projecting portion in this embodiment, is formed on that surface of the transport belt  543  which comes into contact with the heat sink  403 . The projection  542  is, for example,  1  mm in height, and its apex portion has a rounded shape provided with chamfering. In addition, the side surfaces of the projection  542  which come into contact with the heat sink  403  are not vertical, but are formed as inclined surfaces whose angle with respect to a vertical line perpendicular to the belt surface is 10 to 30° or thereabouts. The number of the projections  542  is not limited, but it is necessary to adjust the timing of transport of the printing paper so that the projection  542  and the printing paper will not overlap. As the projection comes into contact with the edge of the heat sink  403 , the abrasion powder adhered to the edge of the heat sink  403  is scraped off. 
         [0049]      FIG. 8  is a conceptual diagram illustrating an example of a control system in the case where the configuration shown in  FIG. 7  is adopted. In  FIG. 8 , a paper setting section  551  acquires information concerning the printing paper for forming an image thereon. A paper transport timing control section  552  is an example of a controlling section that controls the feeding section so that the projecting portion of the transporting section and the recording material will not overlap. The paper transport timing control section  552  outputs a signal for controlling a timing for feeding the printing paper from the recording material accommodating unit  101  shown in  FIG. 1  to the transport path, to the drive mechanism of the feed roll  16  for feeding the printing paper from the recording material accommodating unit  101 . An image formation controlling section  553  controls image formation processing in the image forming section  10 . A fan controlling section  554  controls the operation of the fans  510  to  512 . 
       (Operation) 
       [0050]    Hereafter, a description will be given of an example of the operation which is executed by the control system shown in  FIG. 8 .  FIG. 9  is a flowchart illustrating an example of the operation which is executed by the control system shown in  FIG. 8 . When image formation processing is started (Step S 601 ), the operation of the transport roller and the like necessary for transporting the printing paper on the transport path  103 , the rotation of the photoconductor drum in the image forming section  10 , and the operation of the heating fixing unit  105  and the cooling device  107  are started (Step S 602 ). In addition, the rotation of the fans  510  to  512  is started by the function of the fan controlling section  554 . 
         [0051]    Next, in the paper setting section  551 , information concerning the printing paper subject to image formation (paper size and paper quality) is acquired (Step S 603 ). Next, an arithmetic operation in which at which timing the printing paper is to be fed from the recording material accommodating unit  101  to the transport path  103  is calculated on the basis of the acquired information concerning the printing paper is carried out in the paper transport timing control section  552  (Step S 604 ). In this arithmetic operation, the timing is calculated for feeding the printing paper  102  from the recording material accommodating unit  101  toward the cooling device  107  so that the printing paper will not overlap with the projection  542  shown in  FIG. 7  at the stage when the printing paper reached the cooling device  107 . 
         [0052]    After the result of the arithmetic operation for calculating the transport timing has been obtained, a control signal is sent from the paper transport timing control section  552  to the drive mechanism of the feed roll  16  on the basis of this result, to start the transport of the printing paper (Step S 605 ). Then, the toner image forming processing onto the printing paper in the image forming section  10  is controlled by the control signal from the image formation controlling section  553  (Step S 606 ), and this toner image is heated and fixed by the heating fixing unit  105 . 
         [0053]    The printing paper subjected to heating/fixing processing is cooled in the cooling device  107 , and is discharged in the rightward direction in the drawing. At the time of this cooling in the cooling device  107 , since the timing of the feeding of the printing paper  102  from the first recording material accommodating unit  101  is adjusted by making use of the result of the arithmetic operation carried out in Step S 604 , the printing paper in the state of being pressed against the transport belt  401  does not overlap with the projection  542  shown in  FIG. 7 . 
         [0054]    After Step S 606 , if the processing of image formation is to be terminated, the operation proceeds to Step S 608  to end the processing. In addition, if the processing of image formation is to be effected for ensuing printing paper, the processing in and after Step S 604  is repeated. 
         [0055]    As a method for ensuring that the printing paper does not overlap with the projection  542  shown in  FIG. 7  at the stage when the printing paper has reached the cooling device  107 , it is possible to cite a method in which the transport speed of the transport belt  401  is adjusted at a stage before the printing paper reaches the cooling device  107 , so as to adjust the position of the projection  542  at the stage when the printing paper reaches there. 
       (Fifth Modification) 
       [0056]    In the illustration shown in  FIG. 1 , during the image forming operation, the number of revolutions of the fans  510  to  512  is controlled so that an air volume suitable for cooling the recording material will flow to the heat sink  403 , to thereby execute a cooling mode. Then, at a stage when the number of sheets of the processed recording material has reached a predetermined number, the number of revolutions of the fans  510  to  512  is changed to a value allowing an air volume suitable for blowing away the abrasion powder to be obtained, to thereby execute a cleaning mode. As a result, the cooling efficiency, suppression of wasteful power consumption, and effective removal of the abrasion powder are realized with a good balance. 
         [0057]    In this case, a unit that counts the number of sheets of the recording material for which image formation has been carried out is disposed to count the number of sheets of the processed recording material. In addition, the number of revolutions of the fans  510  to  512  during the cooling mode and during the cleaning mode is controlled by the function of the fan controlling section  554  by adopting the control system shown in  FIG. 8 . 
       (Sixth Modification) 
       [0058]    Hereafter, a description will be given of an example in which a change over is effected between the cooling mode and the cleaning mode by changing over the flow of air to the fans.  FIGS. 10A and 10B  are top views illustrating an example of the cooling device.  FIG. 10A  shows the state of the cooling mode, and FIG.  10 B shows the state of the cleaning mode. 
         [0059]      FIGS. 10A and 10B  show a cooling device  700 . The cooling device  700  has a heat sink  701  similar to the heat sink  403  shown in  FIG. 1 . Air ducts  702  and  703  similar to those shown in  FIG. 1  are respectively disposed on the upstream side and the downstream side, as viewed in the transporting direction of the recording material, of the heat sink  701 . 
         [0060]    In this example, airflow path opening/closing means  707  to  709  are disposed between the heat sink  701  and fans  704  to  706 . The airflow path opening/closing means  707  to  709  have a slatted shutter structure (similar to that of a jalousie), and function as shutters for opening or closing airflow paths. 
         [0061]      FIG. 10A  shows a state in which airflow paths between, on the one hand, the air ducts  702  and  703  and, on the other hand, the fans  704  to  706  are closed, while the airflow path between the heat sink  701  and the fans  704  to  706  is open. This state shown in  FIG. 10A  is one example of the cooling mode for effecting the cooling of the heat sink  701 . 
         [0062]      FIG. 10B  shows a state in which the airflow paths between, on the one hand, the air ducts  702  and  703  and, on the other hand, the fans  704  to  706  are open, while the airflow path between the heat sink  701  and the fans  704  to  706  is closed. This state shown in  FIG. 10B  is one example of the cleaning mode in which air is allowed to flow through the interiors of the air ducts  702  and  703 , and the abrasion powder on the unillustrated transport belt is removed by this air flow. 
       (Other Modifications) 
       [0063]    In the illustration shown in  FIG. 1 , an example has been shown of the case in which the image forming section  10  has the function of forming a color image. However, in the case of exclusive use for monochromatic images, only one image forming unit may be used. In addition, as the image forming section, it is possible to adopt a configuration in which an image is not transferred directly from the photoconductor drum onto the recording medium, but an image is temporarily transferred from the photoconductor drum onto a transfer belt and is then transferred onto the recording material. Furthermore, as the cooling means, it is possible to use in combination a fan and a forced cooling means using a Peltier device or water cooling. Still further, the air duct may be disposed only on the upstream side of the heat sink. 
         [0064]    The present invention can be used for an image forming apparatus. 
         [0065]    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.