Patent Publication Number: US-2023139544-A1

Title: Image forming apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of International Application No. PCT/JP2021/27605 filed on Jul. 26, 2021, and claims priority from Japanese Patent Application No. 2020-155743 filed on Sep. 16, 2020. 
    
    
     BACKGROUND 
     (i) Technical Field 
     The present disclosure relates to an image forming apparatus. 
     (ii) Related Art 
     Japanese Unexamined Patent Application Publication No. 2002-148973 discloses a configuration in which a transfer material is transported by a transport member that is an endless wire and an unfixed toner image transferred onto the transfer material is thermally molten by radiation heat. 
     SUMMARY 
     An image forming apparatus may include an image forming part that forms an image at an image formation position on one surface of a recording medium, a transport part that transports the recording medium while holding a front end side of the recording medium so that the recording medium passes the image formation position, and a transport body that transports the recording medium together with the transport part while supporting the other surface of the recording medium on which an image is to be formed by the image forming part. According to this configuration, the recording medium sometimes flaps if the support of the other surface of the recording medium starts after a rear end of the recording medium is separated from the transport body as a result of transport by the transport part. 
     Aspects of non-limiting embodiments of the present disclosure relate to a technique of suppressing flapping of a recording medium as compared with a configuration in which support of the other surface of the recording medium starts after a rear end of the recording medium is separated from a transport body as a result of transport by a transport part. 
     Aspects of certain non-limiting embodiments of the present disclosure overcome the above disadvantages and/or other disadvantages not described above. However, aspects of the non-limiting embodiments are not required to overcome the disadvantages described above, and aspects of the non-limiting embodiments of the present disclosure may not overcome any of the disadvantages described above. 
     According to an aspect of the present disclosure, there is provided an image forming apparatus including: an image forming part that forms an image at an image formation position on one surface of a recording medium; a transport part that transports the recording medium while holding a front end side of the recording medium so that the recording medium passes the image formation position; a transport body that transports the recording medium together with the transport part while supporting the other surface of the recording medium on which an image is to be formed by the image forming part; and a support part that supports the other surface of the recording medium, the support part starting the support before the other surface of the recording medium is separated from the transport body as a result of transport by the transport part. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An exemplary embodiment of the present disclosure will be described in detail based on the following figures, wherein: 
         FIG.  1    is a schematic view illustrating a configuration of an image forming apparatus according to the present exemplary embodiment; 
         FIG.  2    is a schematic view illustrating a configuration of a toner image forming part according to the present exemplary embodiment; 
         FIG.  3    is a schematic view illustrating a configuration of a fixing device according to the present exemplary embodiment; 
         FIG.  4    is a plan view illustrating the configuration of the fixing device according to the present exemplary embodiment; 
         FIG.  5    is an enlarged schematic view of a part of a fixing unit according to the present exemplary embodiment; 
         FIG.  6    is a plan view illustrating the fixing unit according to the present exemplary embodiment; 
         FIG.  7    is a perspective view illustrating a modification of a chain gripper; 
         FIG.  8    is a side view illustrating a modification of air blowers; 
         FIG.  9    is a schematic view illustrating a configuration of Modification  1 ; and 
         FIG.  10    is a schematic view illustrating a configuration of Modification  2 . 
     
    
    
     DETAILED DESCRIPTION 
     An exemplary embodiment of the present disclosure is described below with reference to the drawings. Note that arrow H in the drawings indicates a vertical direction and an apparatus up-down direction, arrow W indicates a horizontal direction and an apparatus width direction, and arrow D indicates an apparatus front-rear direction (apparatus depth direction). 
     Image Forming Apparatus  10   
     A configuration of an image forming apparatus  10  according to the present exemplary embodiment is described.  FIG.  1    is a schematic view illustrating the configuration of the image forming apparatus  10  according to the present exemplary embodiment. 
     The image forming apparatus  10  illustrated in  FIG.  1    is an example of an image forming apparatus that forms an image on a recording medium. Specifically, the image forming apparatus  10  is an electrophotographic image forming apparatus that forms a toner image on paper P, which is an example of a recording medium. More specifically, as illustrated in  FIG.  1   , the image forming apparatus  10  includes a storage part  50 , a discharge part  52 , an image forming part  12 , an opposed roll  36 , a transport mechanism  60 , a reversing mechanism  80 , a fixing device  100 , an air blowing mechanism  170 , and a cooling part  90 . 
     Storage Part  50   
     The storage part  50  illustrated in  FIG.  1    has a function of storing paper P therein. The image forming apparatus  10  includes plural (e.g., two) storage parts  50 . Paper P is selectively fed out from the plural storage parts  50 . A sheet (cut paper) having a predetermined size is used as the paper P, which is an example of a recording medium. The paper P has a front surface PA (see  FIG.  5   ), which is an example of one surface, and a rear surface PB (see  FIG.  5   ), which is an example of the other surface. The front surface PA of the paper P has an image region GR (see  FIG.  4   ) onto which a toner image is to be transferred, that is, an image region GR on which an unfixed image is to be formed. 
     Discharge Part  52   
     The discharge part  52  illustrated in  FIG.  1    is a part to which paper P on which an image has been formed is discharged. Specifically, paper P onto which an image has been fixed by the fixing device  100  and that has been cooled by the cooling part  90  is discharged to the discharge part  52 . 
     Image Forming Part  12  and Opposed Roll  36   
     The image forming part  12  illustrated in  FIG.  1    is an example of an image forming part that forms an image on one surface of a recording medium. Specifically, the image forming part  12  has a function of forming a toner image on the front surface PA of the paper P by an electrophotographic system. More specifically, as illustrated in  FIG.  1   , the image forming part  12  includes a toner image forming part  20  that forms a toner image and a transfer device  30  that transfers the toner image formed by the toner image forming part  20  onto the paper P. The opposed roll  36  (or called a transfer cylinder or a transfer body) is an example of a transport body. Note that a configuration of the opposed roll  36  is described together with a configuration of the transfer device  30 . 
     Toner Image Forming Part  20   
     The image forming apparatus  10  includes plural toner image forming parts  20  that form toner images of respective colors. The image forming apparatus  10  includes toner image forming parts  20  of four colors, specifically, yellow (Y), magenta (M), cyan (C), and black (K). (Y), (M), (C), and (K) in  FIG.  1    indicate constituent parts corresponding to the respective colors. 
     The toner image forming parts  20  of the respective colors basically have a similar configuration except for used toner. Specifically, as illustrated in  FIG.  2   , each of the toner image forming parts  20  of the respective colors includes a photoconductor drum  21  (photoconductor) that rotates in a direction indicated by arrow A in  FIG.  2    and a charger  22  that charges the photoconductor drum  21 . Furthermore, each of the toner image forming parts  20  of the respective colors includes an exposure device  23  that forms an electrostatic latent image on the photoconductor drum  21  by exposing the photoconductor drum  21  charged by the charger  22  to light and a developing device  24  that forms a toner image by developing the electrostatic latent image formed on the photoconductor drum  21  by the exposure device  23 . 
     Transfer Device  30   
     The transfer device  30  illustrated in  FIG.  1    has a function of performing first transfer by superimposing toner images on the photoconductor drums  21  of the respective colors on an intermediate transfer body and second-transferring the superimposed toner images onto the paper P. Specifically, as illustrated in  FIG.  1   , the transfer device  30  includes a transfer belt  31  serving as an intermediate transfer body, a first transfer roll  33 , and a second transfer part  34 . 
     The first transfer roll  33  has a function of transferring a toner image formed on the photoconductor drum  21  onto the transfer belt  31  at a first transfer position T (see  FIG.  2   ) between the photoconductor drum  21  and the first transfer roll  33 . 
     As illustrated in  FIG.  1   , the transfer belt  31  is an endless belt, and the transfer belt  31  is wound around a plurality of rolls  32 , and thereby a posture thereof is determined. At least one of the plural rolls  32  is driven to rotate, and thereby the transfer belt  31  rotates in a direction indicated by arrow B and transports a first-transferred image to a second transfer position NT. 
     The opposed roll  36  is disposed on a lower side of the transfer belt  31  so as to face the transfer belt  31 . As illustrated in  FIG.  1   , the second transfer part  34  is disposed on an inner side of the transfer belt  31  so that the transfer belt  31  is disposed between the second transfer part  34  and the opposed roll  36 . Specifically, the second transfer part  34  is a corotron. The second transfer position NT is located between the second transfer part  34  and the opposed roll  36 . At the second transfer position NT, the opposed roll  36  and the transfer belt  31  are in contact with each other. In the present exemplary embodiment, the second transfer part  34  and the opposed roll  36  constitute a transfer part  35  that transfers, onto the paper P, a toner image transferred onto the transfer belt  31 . Note that the second transfer position NT is an example of an image formation position. 
     In the present exemplary embodiment, the paper P that is transported while a front end portion thereof is held by a chain gripper  66  (described later) of the transport mechanism  60  is disposed on an outer circumferential surface of the opposed roll  36 , and the paper P is transported by the chain gripper  66  and the opposed roll  36  so as to pass the second transfer position NT. That is, the opposed roll  36  transports the paper P while supporting the rear surface PB of the paper P on the outer circumferential surface thereof. The paper P that has passed the second transfer position NT is further transported by the chain gripper  66 , and as a result, a rear end thereof is separated from the opposed roll  36 . In the transfer part  35 , a toner image transferred onto the transfer belt  31  are transferred onto the paper P passing the second transfer position NT by electrostatic force generated by discharge of the second transfer part  34 . At the second transfer position NT, the paper P is transported while being sandwiched between the opposed roll  36  and the transfer belt  31 . Therefore, the second transfer position NT can be called a sandwiching position where the paper P is sandwiched between the opposed roll  36  and the transfer belt  31 . 
     Transport Mechanism  60   
     The transport mechanism  60  illustrated in  FIG.  1    is a mechanism that transports the paper P. Specifically, the transport mechanism  60  has a function of transporting the paper P stored in the storage part  50  so that the paper P passes the second transfer position NT. Furthermore, the transport mechanism  60  has a function of transporting the paper P from the second transfer position NT to a fixing unit  120 , which will be described later (a heating roll  130  and a pressing roll  140 , which will be described later). In other words, the transport mechanism  60  has a function of transporting, in the fixing device  100 , the paper P onto which a toner image has been transferred. 
     Specifically, as illustrated in  FIG.  1   , the transport mechanism  60  includes a feeding roll  62 , plural transport rolls  64 , and the chain gripper  66 . The feeding roll  62  is a roll that feeds out the paper P stored in the storage part  50 . The plural transport rolls  64  are rolls that transport the paper P fed out by the feeding roll  62  to the chain gripper  66 . 
     As illustrated in  FIGS.  3  and  4   , the chain gripper  66  is a transport part that transports the paper P while holding a front end side (leading end side) of the paper P. Specifically, the chain gripper  66  includes a pair of chains  72  and a gripper  76  serving as a holding member (gripping member). 
     The pair of chains  72  have an annular shape, as illustrated in  FIG.  1   . The chains  72  are spaced apart from each other in the apparatus front-rear direction (the direction D in  FIG.  1   ) (see  FIG.  4   ). The pair of chains  72  are wound around a pair of sprockets (not illustrated) disposed on one end side and the other end side, in an axial direction, of each of the opposed roll  36  and the pressing roll  140 , which will be described later, and a pair of sprockets  74  that are spaced apart from each other in the apparatus front-rear direction. Any of these pairs of sprockets rotates, and thereby the chains  72  rotates in a direction indicated by arrow C (see  FIG.  1   ). 
     As illustrated in  FIG.  4   , an attachment member  75  provided with the gripper  76  extends between the pair of chains  72  along the apparatus front-rear direction. As the attachment member  75 , plural attachment members  75  are fixed to the pair of chains  72  at predetermined intervals along a circumferential direction (circling direction) of the chains  72 . In the drawings, constituent parts of the chains  72  are illustrated as blocks for simplification of illustration of the chains  72 . 
     As illustrated in  FIG.  4   , as the gripper  76 , plural grippers  76  are attached to each of the attachment members  75  at predetermined intervals along the apparatus front-rear direction. Each of the grippers  76  has a function of holding (gripping) a front end portion of the paper P. Since the front end portion of the paper P is held, a position of the paper P in a paper transport direction is easily determined, and therefore position alignment (registration) between the paper P and an image is easy in the transfer part  35 . Specifically, as illustrated in  FIGS.  3  and  5   , each of the grippers  76  has a claw  76 A and a claw rest  76 B. Each of the gripper  76  is configured to hold the paper P by pinching a front end portion of the paper P between the claw  76 A and the claw rest  76 B. Specifically, each of the grippers  76  holds the front end portion of the paper P outside the image region GR (see  FIG.  4   ) where a toner image is to be transferred on the front surface PA. Furthermore, in the present exemplary embodiment, the grippers  76  disposed on a downstream side relative to the paper P in the transport direction hold the front end portion of the paper P from the downstream side in the transport direction. Note that each of the grippers  76  is, for example, configured such that the claw  76 A is pressed against the claw rest  76 B by a spring or the like and the claw  76 A is opened and closed with respect to the claw rest  76 B by action of a cum or the like. Note that a mark called a trim mark for a position for cutting the paper P into a finished size by trimming edges when creating a printed material or for registration in multi-color printing is sometimes formed outside the image region GR. Such an image may be formed so as to overlap the grippers  76  in top view illustrated in  FIG.  4   . Each of the grippers  76  may partially overlap the image region GR but should not overlap an image to be formed. 
     In the chain gripper  66 , the chains  72  circle in a direction indicated by arrow C in a state where the grippers  76  hold the front end portion of the paper P, and thereby the paper P is transported. The chain gripper  66  transports the paper P to the second transfer position NT in a state where the front surface PA faces upward, and thereby causes the paper P to pass the second transfer position NT. Furthermore, the chain gripper  66  transports the paper P to the fixing unit  120 , which will be described later, after the paper P passes a heating part  102 , which will be described later. Note that the chain gripper  66  holds the front end portion but does not hold the rear end side of the paper P, and therefore the rear end side of the paper P that is being transported only by the chain gripper  66  is free. 
     As described above, a part of the chain gripper  66  that has a function of causing the paper P to pass the heating part  102  and transporting the paper P from the heating part  102  to the fixing unit  120  also serves as the fixing device  100 . Note that a part of a transport path along which the paper P is transported in the transport mechanism  60  is indicated by the line with alternate long and short dashes in  FIG.  1   . Hereinafter, an upstream in the transport direction in which the paper P is transported by the transport mechanism  60  is sometimes expressed simply as an “upstream”, and a downstream in the transport direction is sometimes expressed simply as a “downstream”. 
     Reversing Mechanism  80   
     The reversing mechanism  80  illustrated in  FIG.  1    is an example of a reversing mechanism for reversing a recording medium on which an image has been fixed by the fixing device. Specifically, the reversing mechanism  80  is a mechanism that reverses the paper P on which a toner image has been fixed by the fixing device  100 . More specifically, as illustrated in  FIG.  1   , the reversing mechanism  80  includes plural (e.g., two) transport rolls  82 , a reversing device  84 , and plural (e.g., seven) transport rolls  86 . 
     The plural transport rolls  82  are rolls that transport the paper P fed from the fixing device  100  to the reversing device  84 . 
     The reversing device  84  is, for example, a device that reverses the paper P by transporting the paper P while twisting the paper P plural times like a Mobius strip so that a transport direction of the paper P changes, for example, by 90 degrees each time. 
     The plural transport rolls  86  are rolls that transport the paper P that has been reversed by the reversing device  84  to the chain gripper  66 . That is, the plural transport rolls  86  have a function of delivering the reversed paper P to the chain gripper  66 . 
     As described above, the reversing mechanism  80  delivers the paper P to the chain gripper  66  after reversing the paper P, and therefore the chain gripper  66  transports the delivered paper P as paper P having a fixed toner image on the rear surface PB. 
     Note that a part of a transport path along which the paper P is transported in the reversing mechanism  80  is indicated by the line with alternate long and short dashes in  FIG.  1   . The reversing mechanism  80  may be a mechanism that reverses the paper P by switchback. 
     Fixing Device  100   
     The fixing device  100  illustrated in  FIG.  3    is an example of a fixing device that fixes an image formed by the image forming part on a recording medium. Specifically, the fixing device  100  is a device that fixes a toner image transferred by the transfer device  30  onto the paper P. 
     As illustrated in  FIG.  1   , the fixing device  100  is disposed on a downstream side relative to the second transfer position NT in the transport direction of the paper P. As illustrated in  FIG.  3   , the fixing device  100  includes the heating part  102 , the chain gripper  66 , and the fixing unit  120  (fixing part). 
     Heating Part  102   
     The heating part  102  illustrated in  FIG.  3    is an example of a heating part that heats a front surface of a recording medium in a non-contact manner. Specifically, the heating part  102  has a function of heating the front surface PA of the paper P transported by the chain gripper  66  in a non-contact manner. 
     This heating part  102  is disposed on a downstream side relative to the second transfer position NT (see  FIG.  1   ) in the transport direction of the paper P so as to face the front surface PA of the paper P transported by the chain gripper  66 . Specifically, the heating part  102  includes a reflection plate  104 , plural heaters  106  (heating source), and a metal mesh  112 . 
     Reflection Plate  104   
     The reflection plate  104  has a function of reflecting infrared rays from the heaters  106  toward an apparatus lower side (toward the paper P transported by the chain gripper  66 ). The reflection plate  104  is, for example, a metal plate such as an aluminum plate. The reflection plate  104  has a box shape that is opened on the apparatus lower side. 
     Heaters  106   
     The heaters  106  are cylindrical infrared heaters that are long in the apparatus front-rear direction. The plural (e.g.,  40 ) heaters  106  are arranged along the apparatus width direction in the reflection plate  104 . Specifically, each of the heaters  106  includes a carbon filament  109  and a cylindrical quartz tube  108  in which the carbon filament  109  is stored. A black infrared radiation film is provided on a front surface of the quartz tube  108 . Since the black infrared radiation film is provided on the front surface of the quartz tube  108 , the heaters  106  efficiently radiate infrared rays, for example, as compared with a case where a white film is provided. In the present exemplary embodiment, black is a color whose chromaticity deviation from an achromatic point (x=0.333, y=0.333, Y=0) is within 100 in terms of a color difference ΔE. Note that in  FIG.  3   , an enlarged view of the heater  106  is illustrated on an upper left side of the heating part  102  in order to illustrate a specific configuration of the heaters  106 . A wavelength peak of a radiation wavelength of an infrared ray of the infrared heaters  106  according to the present exemplary embodiment is within a range from 2 μm to 5 μm inclusive and is within a far-infrared range. A surface temperature of the heaters  106  of the heating part  102  is a predetermined temperature within a range from 300° C. to 1175° C. inclusive. In the present exemplary embodiment, 20 to 100 heaters  106  that efficiently radiate a far-infrared ray are arranged in the apparatus width direction per meter of the length of the reflection plate  104  in the apparatus width direction, and thereby a good heating distribution is obtained. 
     In a case where toner on a wide recording medium that has an A2 size or larger is transported while a long side thereof is disposed along a transport direction of the recording medium and is heated by less than 20 far-infrared heaters  106  per meter, a voltage applied to a carbon filament needs to be increased to increase an output amount of each heater  106 . In this case, a temperature of the black infrared radiation film rises, and melting of toner caused by heat conduction from surrounding air heated by a near-infrared light component become more dominant than a far-infrared ray. As a result, melting unevenness occurs close to the heaters  106  and between the heaters  106 . On the other hand, in a case where 20 or more heaters  106  are provided per meter, radiation of a far-infrared ray can be made dominant in the carbon filament, and therefore a far-infrared ray, which is less dependent on a distance from a radiation source concerning toner melting, can be effectively used as compared with a case where less than 20 heaters  106  are provided. This reduces melting unevenness between the heaters  106 . In a case where more than 100 heaters  106  are provided, excessive far-infrared rays are radiated, and therefore it becomes difficult to control a temperature of an object to be irradiated to such a degree that toner melts, and it becomes difficult to control a temperature of the fixing device in a later stage since the fixing device is heated by heat of toner. Therefore, it is desirable that 100 or less heaters  106  be provided. In particular, in a case where a recording medium having a B2 size or larger is transported while a long side thereof is disposed along a transport direction of the recording medium, it is desirable that 30 or more and 50 or less heaters  106  be provided. 
     Metal Mesh  112   
     The metal mesh  112  is fixed to an edge portion of an opening on a lower side of the reflection plate  104 . Accordingly, the metal mesh  112  serves as a partition between an inside of the reflection plate  104  and an outside of the reflection plate  104 . The metal mesh  112  prevents contact between the paper P transported by the chain gripper  66  and the heaters  106 . 
     Chain Gripper  66   
     The chain gripper  66  illustrated in  FIG.  3    is an example of a transport part that transports a recording medium so that a front surface of the recording medium faces a heating part. The grippers  76  of the chain gripper  66  are an example of a holding part that holds at least a front end side of a recording medium. Note that the front end side of the recording medium is a portion of the recording medium on a downstream side (front side) relative to a center thereof in the transport direction. 
     Specifically, as described above, the chains  72  circle in the direction indicated by arrow C while the grippers  76  are holding the front end portion of the paper P, and thereby the chain gripper  66  transports the paper P so that the front surface PA of the paper P faces the heaters  106  of the heating part  102 . That is, the chain gripper  66  has a function of causing the paper P to pass a heating region of the heating part  102 . Note that a rear end side of the paper P is not held and is free while the paper P is being transported by the chain gripper  66 . 
     Furthermore, the chain gripper  66  has a function of transporting the paper P from the heating part  102  and the fixing unit  120 . As described above, a part of the chain gripper  66  that has the function of causing the paper P to pass the heating region of the heating part  102  and transporting the paper P from the heating part  102  and the fixing unit  120  functions as an example of a transport part of the fixing device  100 . 
     Fixing Unit  120   
     The fixing unit  120  illustrated in  FIG.  3    is a fixing part that fixes an image on the paper P onto the paper P. Specifically, the fixing unit  120  has a function of fixing a toner image onto the paper P by heating and pressing the paper P while making contact with the paper P. Although a case where the fixing unit  120  that heats and presses the paper P is used is described in the present exemplary embodiment, heating is not necessarily needed, and an aspect in which only pressing by a pressing part is performed for the purpose of improving a surface property of toner molten by the heating part  102  in a previous step, for example, for the purpose of adjusting gloss is also applicable. 
     As illustrated in  FIG.  3   , the fixing unit  120  is disposed on a downstream side relative to the heating part  102  in the transport direction of the paper P. Specifically, the fixing unit  120  includes the heating roll  130 , the pressing roll  140 , and a driven roll  150 . 
     Heating Roll  130   
     The heating roll  130  illustrated in  FIG.  3    is an example of a heating member that is disposed on a downstream side relative to the heating part in the transport direction and heats a recording medium. Specifically, the heating roll  130  is disposed on a downstream side relative to the heating part  102  in the transport direction and has a function of heating the paper P by making contact with the paper P. The heating roll  130  is disposed so as to make contact with the front surface PA of the paper P and have an axial direction in the apparatus front-rear direction. 
     The heating roll  130  includes a cylindrical base member  132 , a rubber layer  134  provided on an outer circumference of the base member  132 , a release layer  136  provided on an outer circumference of the rubber layer  134 , and a heater  138  (heating source) that is stored in the base member  132 . The heater  138  is, for example, one or more halogen lamps. 
     As illustrated in  FIG.  6   , the heating roll  130  is provided with an abutted part  139  that abuts on an abutting part  149  (described later) of the pressing roll  140 . The abutted part  139  is an example of an abutted part of a heating roll. Specifically, the abutted part  139  has a cylindrical shape having an external diameter equivalent to the heating roll  130 . Furthermore, the abutted part  139  is provided at one end portion and the other end portion of the heating roll  130  in an axial direction so as to be coaxial with the heating roll  130  and rotate integrally with the heating roll  130 . 
     Driven Roll  150   
     The driven roll  150  illustrated in  FIG.  3    is disposed so as to make contact with a region on the outer circumferential surface of the heating roll  130  other than a region that makes contact with the paper P and have an axial direction in the apparatus front-rear direction. The driven roll  150  includes a cylindrical base member  152  and a heater  154  (heating source) stored in the base member  152 . The driven roll  150  is driven by the heating roll  130  to rotate and heats the heating roll  130 . Since the heating roll  130  is heated by the driven roll  150  and the heating roll  130  itself includes the heater  138 , a front surface temperature of the heating roll  130  becomes a predetermined temperature. 
     Pressing Roll  140   
     The pressing roll  140  illustrated in  FIG.  3    is an example of a pressing member that presses a recording medium together with the heating roll and has, on an outer circumferential surface thereof, a recessed part into which the holding part enters. Specifically, the pressing roll  140  has a function of pressing the paper P against the heating roll  130 . The pressing roll  140  is disposed on a lower side of the heating roll  130  so as to have an axial direction in the apparatus front-rear direction. 
     The pressing roll  140  includes a cylindrical base member  142 , a rubber layer  144  provided on an outer circumference of the base member  142 , and a release layer  146  provided on an outer circumference of the rubber layer  144 . 
     A perimeter of the pressing roll  140  is set identical to an interval at which the grippers  76  are provided on the chains  72 . As illustrated in  FIGS.  5  and  6   , the pressing roll  140  has, on an outer circumferential surface thereof, a recessed part  148  extending in the apparatus front-rear direction. 
     When the grippers  76  that hold the front end side of the paper P passes between the pressing roll  140  and the heating roll  130 , the grippers  76  enter into the recessed part  148 . 
     As illustrated in  FIG.  6   , the pressing roll  140  has the abutting part  149  that abuts on the abutted part  139  of the heating roll  130 . The abutting part  149  is an example of an abutting part that is provided outside the recessed part of the pressing roll in an axial direction and keeps a center distance between the heating roll  130  and the pressing roll  140  by abutting on the abutted part  139 . 
     The abutting part  149  has a cylindrical shape having an external diameter equivalent to the pressing roll  140 . The abutting part  149  is provided outside the recessed part  148  of the pressing roll  140  in the axial direction. Specifically, the abutting part  149  is provided at one end portion and the other end portion of the pressing roll  140  in the axial direction so as to be coaxial with the pressing roll  140  and rotate integrally with the pressing roll  140 . 
     The heating roll  130  and the pressing roll  140  rotate in a state where the abutting part  149  is abutting on the abutted part  139 , and thereby the center distance between the heating roll  130  and the pressing roll  140  is kept even when the recessed part  148  faces the heating roll  130 . As a result, a surface pressure of a load by which the pressing roll  140  is biased toward the heating roll  130  by a biasing member (not illustrated) falls within a certain range. A surface pressure in a conventional typical fixing device is approximately 400 kPa. 
     In the fixing unit  120 , the pressing roll  140  is driven by a driving part (not illustrated) to rotate, the heating roll  130  is driven by the pressing roll  140  to rotate, and the driven roll  150  is driven by the heating roll  130  to rotate. 
     Air Blowing Mechanism  170   
     The air blowing mechanism  170  illustrated in  FIG.  3    is an example of a support part and is an example of an air blowing part. The air blowing mechanism  170  is a mechanism that blows air toward the rear surface PB of the paper P. Specifically, the air blowing mechanism  170  includes an air blower  160  and a ventilation plate  180 . 
     Air Blower  160   
     The air blower  160  illustrated in  FIG.  3    is a device that blows air toward the rear surface PB of the paper P. As the air blower  160 , plural air blowers  160  are disposed on an inner side (inner circumferential side) of the chains  72  when viewed in the apparatus front-rear direction so as to be located below the heating part  102 . As illustrated in  FIGS.  3  and  4   , the plural air blowers  160  are disposed two-dimensionally (in a matrix) along the transport direction of the paper P and the apparatus front-rear direction. Note that in  FIG.  4   , blades of some of the air blowers  160  are omitted for simplification of illustration of the air blowers  160 . 
     As illustrated in  FIG.  3   , each of the air blowers  160  faces upward and blows air upward. That is, each of the air blowers  160  is configured to blow air only toward the rear surface PB of the paper P facing the heating part  102  in a thickness direction of the paper P. In other words, each of the air blowers  160  is disposed so as to face the rear surface PB of the paper P transported by the chain gripper  66 . In still other words, the chain gripper  66  transports the paper P so that the rear surface PB of the paper P faces the air blowers  160 . 
     Each of the air blowers  160  is, for example, an axial flow blower that blows air in an axial direction. Note that each of the air blowers  160  may be a centrifugal blower that blows air in a centrifugal direction, such as a multi-blade blower (e.g., a sirocco fan). 
     The air blowers  160  blow air toward the rear surface PB of the paper P transported by the chain gripper  66 , and thus the paper P floats up. This brings the rear surface PB of the paper P into a non-contact state. Specifically, at least the rear surface PB within the image region GR of the paper P is brought into a non-contact state. More specifically, at least the rear surface PB within the image region GR of the paper P is brought into a state of not being in contact with the ventilation plate  180 . Therefore, the air blowers  160  have a function of keeping a non-contact state of the rear surface PB within the image region GR of the paper P while the paper P is being transported by the chain gripper  66 . Note that the rear surface PB outside the image region GR of the paper P is permitted to make contact with the ventilation plate  180 . Note that it is necessary to prevent air blown from an air outlet of each of the air blowers  160  from being directly supplied to the front surface PA of the paper P. This is because the image forming apparatus  10  according to the present exemplary embodiment is an image forming apparatus that forms an image by using dry toner and if air is directly supplied to the front surface of the paper P from the air outlet, an unfixed toner image may be disturbed. Furthermore, by supplying air only to the rear surface PB, toner transferred onto the front surface PA is less cooled. 
     Ventilation Plate  180   
     The ventilation plate  180  illustrated in  FIG.  3    is an example of a ventilation part having plural ventilation holes through which air blown from the air blowing part toward the rear surface of the recording medium passes. Specifically, the ventilation plate  180  is a plate having plural ventilation holes  182  through which air blown from the air blowers  160  toward the rear surface PB of the paper P passes. 
     The ventilation plate  180  is disposed on an inner side (inner circumferential side) of the chains  72  so as to be located below the heating part  102  and above the air blowers  160  when viewed from the apparatus front-rear direction and have a thickness direction in the apparatus up-down direction. That is, the ventilation plate  180  is disposed on an air blowing direction side of the air blowers  160  so as to cover the air blowers  160 . In other words, the ventilation plate  180  can be regarded as an example of a disposed member that is disposed so as to face the rear surface PB of the paper P transported by the chain gripper  66 . 
     Each of the ventilation holes  182  passes through the ventilation plate  180  in the thickness direction. As illustrated in  FIG.  4   , the plural ventilation holes  182  are disposed two-dimensionally (in a matrix) along the transport direction of the paper P and the apparatus front-rear direction. In  FIG.  4   , some of the ventilation holes  182  are omitted for simplification of illustration of the ventilation plate  180 . 
     The ventilation plate  180  allows air blown from the air blowers  160  to pass through the plural ventilation holes  182  and hit the rear surface PB of the paper P transported by the chain gripper  66 . In other words, the air blowers  160  blow air toward the rear surface PB of the paper P transported by the chain gripper  66  through the ventilation plate  180  having the plural ventilation holes  182 . 
     The ventilation plate  180  is a metal plate. The ventilation plate  180  also functions as a reflection plate that reflects an infrared ray from the heaters  106  toward an apparatus upper side (side where the paper P is transported by the chain gripper  66 ). 
     As described above, in the air blowing mechanism  170 , the air blowers  160  blow air toward the rear surface PB of the paper P transported by the chain gripper  66  through the ventilation plate  180  having the plural ventilation holes  182 . In this way, the air blowing mechanism  170  supports the paper P from the rear surface PB. 
     Position of Air Blowing Region in Air Blowing Mechanism  170   
     In the air blowing mechanism  170 , as illustrated in  FIG.  3   , an upstream end  170 X of an air blowing region set by the air blowers  160  and the ventilation plate  180  is disposed between the second transfer position NT and a holding position  66 X illustrated in  FIG.  3   . Specifically, the upstream end  170 X is disposed on a downstream side relative to the second transfer position NT and an upstream side relative to the holding position  66 X. 
     Specifically, the upstream end  170 X of the air blowing region of the air blowing mechanism  170  is disposed between a separation position  36 X illustrated in  FIG.  3    and the holding position  66 X. Specifically, the upstream end  170 X is disposed on a downstream side relative to the separation position  36 X and an upstream side relative to the holding position  66 X. 
     The separation position  36 X is a position at which the rear end of the paper P transported by the chain gripper  66  is separated from the opposed roll  36 . The separation position  36 X can be regarded as a downstream end of a region where the paper P makes contact with the outer circumferential surface of the opposed roll  36 . In the present exemplary embodiment, the separation position  36 X is located on a downstream side relative to the second transfer position NT. In some cases, the rear end of the paper P is separated at a downstream end  36 Z (a position rotated from an upper end of the opposed roll  36  by 270 degrees in a clockwise direction) of the opposed roll  36 . That is, in some cases, the separation position  36 X is located at the downstream end  36 Z of the opposed roll  36 . 
     The holding position  66 X is a position at which the chain gripper  66  holds the paper P in a case where the rear end of the paper P transported by the chain gripper  66  is located at the separation position  36 X. The paper Pin this case is paper P of a minimum size used in the image forming apparatus  10 . Note that it is at least necessary that the holding position  66 X is a holding position defined by paper P of a maximum size used in the image forming apparatus  10 . 
     The air blowing mechanism  170  starts support of the rear surface PB by blown air before the rear end of the paper P passes the separation position  36 X. That is, the air blowing mechanism  170  starts support of the rear surface PB by blown air before the rear end of the paper P is separated from the opposed roll  36 . Specifically, the air blowing mechanism  170  starts support of the rear surface PB by blown air before the rear end of the paper P finishes passing the second transfer position NT. That is, the air blowing mechanism  170  starts support of the rear surface PB by blown air while the paper P is passing the second transfer position NT. 
     Furthermore, the air blowing mechanism  170  supports the rear surface PB of the paper P by blowing air toward the rear surface PB of the paper P that has passed the second transfer position NT until the rear end of the paper P reaches the downstream side of the air blowing region. As described above, the air blowing mechanism  170  starts support of the rear surface PB of the paper P before the rear end of the paper P is separated from the opposed roll  36  as a result of transport by the chain gripper  66 . At the start of air blowing, an airflow tends to become unstable. Also from this point of view, it is desirable that air blowing is started while the opposed roll  36  and the rear surface PB of the paper P are in contact (before separation). 
     Since the upstream end  170 X of the air blowing region of the air blowing mechanism  170  is disposed between the separation position  36 X and the holding position  66 X illustrated in  FIG.  3    as described above, the rear end of the paper P is separated from the opposed roll  36  while air is being blown toward a rear end side of the rear surface PB of the paper P relative to the holding position  66 X. That is, the rear end of the paper P is separated from the opposed roll  36  while the air blowing mechanism  170  is supporting the rear surface PB on the rear end side relative to the holding position  66 X. 
     In the air blowing mechanism  170 , the air blowing region set by the air blowers  160  and the ventilation plate  180  is set longer toward an upstream in the transport direction of the paper P than a heating region set by the heating part  102 . That is, air is blown toward the rear surface PB of the paper P that has passed the transfer part  35  by the air blowers  160  before the paper P enters the heating part  102 . Accordingly, the paper P is carried to the heating part  102  while keeping a stable posture. More desirably, the air blowing region is set from a point that immediately follows the transfer part  35  and does not overlap the transfer belt  31  in a gravitational direction toward a downstream in the transport direction of the paper P. 
     In the air blowing mechanism  170 , the air blowing region set by the air blowers  160  and the ventilation plate  180  is set longer toward a downstream in the transport direction of the paper P than the heating region set by the heating part  102 . That is, the air blowing mechanism  170  blows air toward the rear surface PB of the paper P even after the paper P passes the heating region of the heating part  102 . Accordingly, the paper P is carried to the fixing unit  120  while keeping a stable posture. 
     Cooling Part  90   
     As illustrated in  FIG.  1   , the cooling part  90  is disposed on a downstream side relative to the fixing unit  120  in the transport direction of the paper P. The cooling part  90  includes plural (e.g., two) cooling rolls  92  arranged in the apparatus width direction. 
     The cooling rolls  92  are cylindrical rolls made of a metal or the like. Air passes inside the cooling rolls  92 , and thereby the cooling rolls  92  air-cool the paper P (cool the paper P through heat exchange with air). 
     Supplements Concerning Image Forming Apparatus  10   
     A length of the paper P used in the image forming apparatus  10  in the transport direction is, for example, within a range from 570 mm to 680 mm inclusive. A distance along a circumferential direction of the chains  72  (transport direction) between the plural grippers  76  arranged along the circumferential direction is, for example, 840 mm. A distance along the circumferential direction (transport direction) between sheets of paper P held by the plural grippers  76  is, for example, within a range from 160 mm to 270 mm inclusive. 
     A distance L 1  from an upstream end  170 Z of the air blowing mechanism  170  to the downstream end  36 Z of the opposed roll  36  is, for example, within a range from 230 mm to 260 mm inclusive. A diameter of the opposed roll  36  is, for example, 285 mm. A distance L 2  from the second transfer position NT to the downstream end  36 Z of the opposed roll  36  is, for example, 140 mm. 
     A distance L 3  from an upstream end of the heating part  102  (an upstream end of the heating region) to the downstream end  36 Z of the opposed roll  36  may be longer than the maximum paper length 680 mm. When the paper P burns because of the heating part  102 , the opposed roll  36  may burn if the paper P is in contact with the opposed roll  36 . However, according to this configuration, the burning can be avoided. 
     An upper surface of the air blowing mechanism  170  (an upper surface of the ventilation plate  180  in the present exemplary embodiment) or at least an upstream end of the upper surface of the air blowing mechanism  170  (the upper surface of the ventilation plate  180  in the present exemplary embodiment) and at least an upstream end of the air blowing region are located below an upper end of the opposed roll  36  in the gravitational direction. 
     In the present exemplary embodiment, it is also possible to employ a configuration in which the upstream end  170 Z of the air blowing mechanism  170  and the upstream end  170 X of the air blowing region are disposed between the separation position  36 X and the holding position  66 X illustrated in  FIG.  3    and air blowing is started after the rear end of the paper P is separated from the opposed roll  36  and before the rear end of the paper P makes contact with the air blowing mechanism  170  (the air blowers  160  or the ventilation plate  180 ). Note that the paper P makes contact with the air blowing mechanism  170  because the paper P droops down. The configuration may be, for example, realized by starting air blowing at a timing at which the rear end of the paper P is detected by a sensor disposed on a downstream side relative to the separation position  36 X or may be, for example, realized by starting air blowing after elapse of a predetermined period from a timing of detection of the rear end of the paper P by a sensor disposed at a predetermined position. The predetermined period is, for example, measured by a timer. 
     Alternatively, it is also possible to employ a configuration in which air blowing is started after the paper P is separated from the opposed roll  36  and before the rear end of the paper P falls below the upper surface of the air blowing mechanism  170  in the gravitational direction between the upstream end  170 Z of the air blowing mechanism  170  and the opposed roll  36 . This configuration may be, for example, realized by starting air blowing at a timing at which the rear end of the paper P is detected by a sensor disposed on a downstream side relative to the separation position  36 X or may be, for example, realized by starting air blowing after elapse of a predetermined period from a timing of detection of the rear end of the paper P by a sensor disposed at a predetermined position. The predetermined period is, for example, measured by a timer. 
     In the present exemplary embodiment, the reflection plate  104  and a heat-insulating cover are integral with each other. The upstream end  170 Z of the air blowing mechanism  170  and the upstream end  170 X of the air blowing region are located on an upstream side relative to the heating part  102 , and the air blowing mechanism  170  and the air blowing region are present on an upstream side relative to the reflection plate  104  and the heat-insulating cover. 
     If the paper P makes contact with a member that tends to receive heat such as the reflection plate  104  or the heat-insulating cover, the paper P may burn. Furthermore, when the paper P makes contact with such a member, disturbance of a toner image can occur. In the present exemplary embodiment, the air blowing mechanism  170  and the air blowing region are present on an upstream side relative to the reflection plate  104  and the heat-insulating cover, and therefore the paper P is supported stably in a non-contact manner before the paper P passes the reflection plate  104  and the heat-insulating cover. 
     The air blowing mechanism  170  and the air blowing region are also present on a downstream side relative to the reflection plate  104  and the heat-insulating cover. Accordingly, the paper P is stably supported until the paper P is transported to the fixing unit  120  after passing the reflection plate  104  and the heat-insulating cover. Note that the reflection plate  104  and the heat-insulating cover may be separate members. 
     Operation According to Present Exemplary Embodiment 
     The paper P fed out from the storage part  50  illustrated in  FIG.  1    is transported by the plural transport rolls  64  and is delivered to the chain gripper  66 . The paper P delivered to the chain gripper  66  is transported to the second transfer position NT by the chain gripper  66  while a front end portion of the paper P is being held by the grippers  76 , and a toner image is transferred from the transfer belt  31  onto the front surface PA. As illustrated in  FIG.  3   , the paper P onto which the toner image has been transported is transported by the chain gripper  66  in a state where the front surface PA faces the heaters  106  of the heating part  102 , and thus the toner image is heated. 
     The paper P whose toner image has been heated by the heating part  102  is further transported to the fixing unit  120  by the chain gripper  66  and is pressed and heated by being held between the heating roll  130  and the pressing roll  140 . In this way, the toner image is fixed onto the paper P. In a case where an image is formed only on the front surface PA of the paper P, the paper P onto which the toner image has been fixed is discharged to the discharge part  52  after being cooled by the cooling rolls  92  of the cooling part  90  illustrated in  FIG.  1   . 
     In the present exemplary embodiment, as described above, the air blowing mechanism  170  starts support of the rear surface PB of the paper P by blown air after the rear end of the paper P is separated from the opposed roll  36  as a result of transport by the chain gripper  66 . That is, the air blowing mechanism  170  starts support of the rear surface PB of the paper P by blown air before the rear end of the paper P is separated from the opposed roll  36 . 
     In a configuration (hereinafter referred to as a configuration A) in which the air blowing mechanism  170  starts support of the rear surface PB of the paper P by blown air after the rear end of the paper P is separated from the opposed roll  36  as a result of transport by the chain gripper  66 , only the front end portion of the paper P is held by the chain gripper  66  until the rear end of the paper P is supported by the air blowing mechanism  170  after being separated from the opposed roll  36 . Accordingly, the paper P sometimes flaps. In particular, in a case where the paper P is thin paper, the paper P is easier to droop down and flap than thick paper. Once the paper P flaps, the flapping of the paper P is unlikely to cease even in a case where the paper P is supported thereafter. In particular, in a case where an unfixed image of toner, which is an example of powder, is on the paper P from the second transfer position NT to the fixing unit  120 , if the paper P flaps, the unfixed image is more likely to make contact with another member in the image forming apparatus  10  or vibration is more likely to occur due to the flapping. This may, for example, undesirably disturb the unfixed toner image or damage or fold the paper P. Furthermore, if the paper P flaps, the paper P is more likely to make contact with the heating part  102 , and therefore not only the toner image on the front surface of the paper P is disturbed, but also the paper P burns. 
     On the other hand, in the present exemplary embodiment, since support of the rear surface PB of the paper P is started before the rear end of the paper P is separated from the opposed roll  36 , flapping of the paper P is suppressed as compared with the configuration A. Since the flapping of the paper P is suppressed, disturbance of the toner image and contact of the paper P with the heating part  102  are less likely to occur. 
     In the present exemplary embodiment, the air blowing mechanism  170  starts support of the rear surface PB by blown air before the rear end of the paper P finishes passing the second transfer position NT. That is, in the present exemplary embodiment, support of the rear surface PB starts from a state where the paper P is held between the opposed roll  36  and the transfer belt  31 . Accordingly, flapping of the paper P is suppressed as compared with a configuration in which the air blowing mechanism  170  starts support of the rear surface PB by blown air after the rear end of the paper P finishes passing the second transfer position NT. 
     In the present exemplary embodiment, the air blowing mechanism  170  supports the rear surface PB on a rear end side relative to the holding position at which the chain gripper  66  holds the paper P. Accordingly, flapping of the paper P is suppressed as compared with a configuration in which the air blowing mechanism  170  supports the rear surface PB at a same position as the holding position at which the chain gripper  66  holds the paper P. 
     In the present exemplary embodiment, the air blowing mechanism  170  supports the rear surface PB of the paper P in a non-contact manner, and therefore the air blowing mechanism  170  is less likely to interfere with the chain gripper  66  than in a configuration in which the air blowing mechanism  170  supports the recording medium while making contact with the rear surface PB of the paper P. 
     In the present exemplary embodiment, the rear surface PB of the paper P is supported by blown air, and therefore a degree of freedom of a material used as the recording medium is higher than a configuration in which the rear surface PB of the paper P is supported in a non-contact manner by magnetic force or electrostatic force. 
     In the present exemplary embodiment, as illustrated in  FIG.  3   , the air blowers  160  blow air toward the rear surface PB of the paper P transported by the chain gripper  66  in the heating part  102 , and thereby the air blowers  160  keep a non-contact state of the rear surface PB within the image region GR of the paper P while the paper P is being transported. 
     In a configuration (first configuration) in which the rear surface PB within the image region GR of the paper P makes contact with a constituent part of the apparatus when the paper P is transported so that the front surface PA faces the heating part  102 , in a case where the constituent part (e.g., the ventilation plate  180 ) with which the paper P makes contact is heated by the heating part  102  as a result of continued operation of the fixing device  100 , the paper P is heated by the constituent part, and melting of toner proceeds. 
     Accordingly, a toner melting degree at an initial stage of operation of the fixing device  100  and a toner melting degree after continuation of operation of the fixing device  100  are different. Therefore, heating temperatures of the heating part  102  and the heating roll  130  at the initial stage of operation of the fixing device  100  and heating temperatures of the heating part  102  and the heating roll  130  after continuation of operation of the fixing device  100  need to be made different, and therefore it becomes difficult to control the heating temperatures. 
     On the other hand, in the present exemplary embodiment, the air blowers  160  maintain a non-contact state of the rear surface PB within the image region GR of the paper P during transport of the paper P, and therefore the rear surface PB of the paper P is not heated and influence of heat (e.g., conductive heat) received from the rear surface PB of the paper P is reduced as compared with the first configuration. In other words, control of the heating temperatures of the heating part  102  and the heating roll  130  is prevented from becoming complicated, and in a case of both-sided printing, toner on the rear surface PB of the paper P is kept from melting due to influence of heat, and a toner image is kept from being disturbed due to contact of the rear surface PB of the paper P with the air blowing mechanism  170 . 
     In particular, even in a case where an image to be formed on both surfaces of the paper P and the paper P having a fixed image on the rear surface PB is transported by the chain gripper  66  in the heating part  102 , the rear surface PB of the paper P is not heated, and melting of the fixed toner image is suppressed as compared with the first configuration. In particular, from a purpose of suppressing melting of a fixed toner image in a case where an image is to be formed on both surfaces of the paper P, the transport part and the air blowing part are controlled so that the rear surface PB is in a non-contact state when the paper P having a fixed toner image on the rear surface PB passes the heating part  102 . In a case where the paper P does not have a fixed toner image on the rear surface PB and has an unfixed toner image only on the front surface PA, the rear surface PB may be always in contact with a member such as the ventilation plate  180  during transport. 
     In the present exemplary embodiment, in the heating part  102 , the air blowers  160  blow air toward the rear surface PB of the paper P transported by the chain gripper  66  through the ventilation plate  180  having the plural ventilation holes  182 . Accordingly, air hits the rear surface PB of the paper P more evenly than in a configuration (second configuration) in which air blown from the air blowers  160  directly hits the rear surface PB of the paper P without passing through the ventilation holes  182 . As a result, a posture of the paper P is less likely to change than in the second configuration. 
     In the present exemplary embodiment, as illustrated in  FIG.  5   , the grippers  76  holding the front end side of the paper P enter into the recessed part  148  in a case where the grippers  76  pass between the pressing roll  140  and the heating roll  130 . Accordingly, the grippers  76  are less likely to hinder pressing of the paper P than in a configuration in which the paper P is pressed between the pressing roll  140  having no recessed part  148  and the heating roll  130 . 
     In the present exemplary embodiment, the heating roll  130  and the pressing roll  140  rotate in a state where the abutting part  149  illustrated in  FIG.  6    is abutting on the abutted part  139 , and therefore a center distance between the heating roll  130  and the pressing roll  140  is kept even in a state where the recessed part  148  faces the heating roll  130 . Accordingly, a fluctuation in pressure pressing the paper P is suppressed as compared with a configuration in which the paper P is pressed between the pressing roll  140  and the heating roll  130  without keeping the center distance. 
     Modification of Chain Gripper  66   
     Although the grippers  76  disposed on a downstream side relative to the paper P in the transport direction hold the front end portion of the paper P from the downstream side in the transport direction of the paper P in the chain gripper  66  in the present exemplary embodiment, this is not restrictive. As an example of the holding part, grippers  761  that are disposed beside both side edges of the paper P and hold front-end side edge portions of the paper P from sides besides the side edges may be used, as illustrated in  FIG.  7   . 
     Other Modifications 
     Although the paper P is used as an example of a recording medium in the present exemplary embodiment, this is not restrictive. The recording medium may be, for example, a film, and the recording medium may be, for example, a sheet member having a sheet shape (paper shape, film shape) other than the paper P. 
     Although the image forming part  12  has the transfer belt  31  as an intermediate transfer body in the present exemplary embodiment, this is not restrictive. The image forming part may be, for example, a direct-transfer-type image forming part. The image forming part may be, for example, an inkjet-type image forming part that forms an image by ejecting ink toward the paper P. 
     Although the transport body is the opposed roll  36  of the transfer part  35  in the present exemplary embodiment, this is not restrictive. The opposed roll  36  may be a support roll or a support block that supports the rear surface PB of the paper P transported from the transfer part  35 . In this case, it is more desirable that the support roll be disposed so as to support the paper P that is being sandwiched by the transfer part  35 . Furthermore, it is desirable that the front surface of the paper P does not make contact with another member until the paper P reaches the heating part  102  after leaving the transfer part  35  or until the paper P reaches the fixing unit  120  after leaving the transfer part  35 . 
     Although the separation position  36 X is located on a downstream side relative to the second transfer position NT in the present exemplary embodiment, this is not restrictive. For example, the separation position  36 X may be located at a downstream end of the second transfer position NT. That is, the rear end of the paper P may be separated from the opposed roll  36  when the rear end of the paper P finishes passing the second transfer position NT. In a case where an inkjet-type image forming part or the like is used as an example of the image forming part, the second transfer position NT (sandwiching position) is not present, and the rear end of the paper P is separated from the opposed roll  36  without sandwiching the paper P disposed on the outer circumferential surface of the opposed roll  36 . 
     Although the air blowing mechanism  170  includes the air blowers  160  and the ventilation plate  180  in the present exemplary embodiment, this is not restrictive. The air blowing mechanism  170  may include only the air blowers  160  without including the ventilation plate  180 . 
     Although the air blowing mechanism  170  starts support of the rear surface PB by blown air before the rear end of the paper P finishes passing the second transfer position NT in the present exemplary embodiment, this is not restrictive. The air blowing mechanism  170  may start support of the rear surface PB by blown air after the rear end of the paper P finishes passing the second transfer position NT as long as the support of the rear surface PB is started before the rear end of the paper P is separated from the opposed roll  36 . Alternatively, air blowing may be started before the paper P enters the second transfer position NT during image formation or air blowing may be always performed during image formation. 
     Although the air blowing mechanism  170  supports the rear surface PB on a rear end side relative to the holding position at which the chain gripper  66  holds the paper P in the present exemplary embodiment, this is not restrictive. For example, in a case where the chain gripper  66  holds a position in a front end side portion of the paper P close to a center in the transport direction, the air blowing mechanism  170  may support the rear surface PB at a same position as the holding position at which the chain gripper  66  holds the paper P. 
     Although the air blowing mechanism  170  supports the rear surface PB of the paper P in a non-contact manner in the present exemplary embodiment, this is not restrictive. For example, the support part may support the recording medium while making contact with the rear surface PB of the paper P. 
     Although the rear surface PB of the paper P is supported by blown air in the present exemplary embodiment, this is not restrictive. For example, the support part may support the rear surface PB of the paper P in a non-contact manner by magnetic force or electrostatic force. 
     Although the air blowers  160  blow air toward the rear surface PB of the paper Pin a thickness direction of the paper P in the present exemplary embodiment, this is not restrictive. For example, the air blowers  160  may blow air obliquely with respect to the thickness direction of the paper P. For example, the air blowers  160  blow air toward the rear surface PB of the paper P obliquely toward an upstream side in the transport direction of the paper P (toward an upper right side in  FIG.  3   ). 
     Furthermore, as illustrated in  FIG.  8   , the air blowers  160  may be disposed outside the paper P in the width direction, and the air blowers  160  may blow air toward the rear surface PB of the paper P from sides beside both side edges of the paper P. In other words, any configuration may be employed as long as air is supplied to the rear surface PB of the paper P so that the paper P floats up. 
     Although air is supplied only to the rear surface PB of the paper P in the present exemplary embodiment, this is not restrictive. Supplying air to the front surface PA of the paper P may be permitted from the following perspectives. 
     The example illustrated in  FIG.  9    is Modification  1  in which air is supplied to the front surface PA from a perspective of stable transport of the paper P. In Modification  1 , air blowers  190  that is disposed so as to face the front surface PA of the paper P and supply air to the front surface PA are provided in addition to the configuration according to the present exemplary embodiment illustrated in  FIG.  3   . A posture of the paper P is kept in parallel with the transport direction by adjusting a relative air volume between air blown from the air blowers  190  and air blown from the air blowers  160 . In this case, from a perspective of using dry toner, an air volume of the air blowers  190  is set smaller than an air volume of the air blowers  160  and is set to such a degree that toner is not scattered by air from the air blowers  190 . 
     In Modification  2  illustrated in  FIG.  10   , an air blower  200  for ventilating a surrounding region of the heating part  102  is provided so as to face a direction orthogonal to the air blowing direction of the air blowers  160 . That is, an air outlet of the air blower  200  is opened in a direction along the front surface PA of the paper P and does not face the front surface PA of the paper P. Air blown from the air blower  200  flows in the direction along the front surface PA of the paper P, and air from the air blower  200  may be supplied to the front surface PA of the paper P. Also in this case, it is desirable that an air amount is set to such a degree that toner is not scattered, as in Modification  1 . 
     In the present exemplary embodiment, an aspect in which the air blowers  160  blow air toward the rear surface PB of the paper P in the thickness direction of the paper P has been described. When the air blowers  160  blow air in a case where no recording medium is present between the heating part  102  and the air blowers  160 , heated air around the heating part  102  may undesirably diffuse in the apparatus. In a case where the air blowers  160  are configured to blow air at a timing at which a recording medium faces the air blowers  160  as a countermeasure for this, blown air is blocked by the recording medium. In other words, by weakening or stopping air blowing between a preceding recording medium and a following recording medium, air supplied from the air blowers  160  to the heating part  102  is reduced, and as a result, diffusion of warmed air in the apparatus is suppressed. Driving of the air blowers  160  may be thus controlled, and driving of the plural air blowers  160  may be individually controlled. 
     The present disclosure is not limited to the above exemplary embodiment, and can be modified, changed, and improved in various ways without departing from the spirit of the present disclosure. For example, the above modifications may be combined as appropriate. The present application is based on Japanese Patent Application No. 2020-155743 filed on Sep. 16, 2020, contents of which are hereby incorporated by reference. 
     The foregoing description of the exemplary embodiments of the present disclosure has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure 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 disclosure and its practical applications, thereby enabling others skilled in the art to understand the disclosure for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the disclosure be defined by the following claims and their equivalents.