Patent Publication Number: US-11661298-B2

Title: Medium transport unit, recording apparatus, and image reading apparatus

Description:
BACKGROUND 
     1. Technical Field 
     The present invention relates to a medium transport unit configured to transport a medium such as a print sheet, a recording apparatus provided with the medium transport unit, and an image reading apparatus provided with the medium transport unit. 
     2. Related Art 
     Examples of an image forming apparatus (recording apparatus) provided with a paper reversing apparatus (medium transport unit) configured to reverse and transport a print sheet (medium) in the related art include a configuration, for example, disclosed in JP-A-9-12198. The paper reversing apparatus provided in the image forming apparatus as described above is configured to reverse the print sheet with a switchback mechanism. 
     In other words, the paper reversing apparatus includes a first reversing paper guide and a second reversing paper guide arranged with a partitioning plate interposed there between, and a third paper transporting channel and a fourth paper transporting channel extending respectively from the first reversing paper guide and the second reversing paper guide respectively, joining together at downstream ends thereof, and connected to an upstream end of a downstream side transporting channel. 
     When print sheets are fed to the first reversing paper guide and the second reversing paper guide alternately from an upstream side transporting channel, the print sheets fed to the first reversing paper guide are reversed in the course of being transported in the third paper transporting channel and are fed to the downstream side transporting channel. In contrast, the print sheets fed to the second reversing paper guide are reversed in the course of being transported in the fourth paper transporting channel and are fed to the downstream side transporting channel. 
     The paper reversing apparatus as described above is configured in such a manner that the third paper transporting channel and the fourth paper transporting channel pass outside the first reversing paper guide and the second reversing paper guide, respectively. Therefore, four routes including the first reversing paper guide, the second reversing paper guide, the third paper transporting channel, and the fourth paper transporting channel are arranged side by side. Therefore, there arises a problem of an increase in size of the apparatus. 
     SUMMARY 
     An advantage of some aspect of the invention is to provide a medium transport unit, a recording apparatus, and an image reading apparatus which can be reduced in size. 
     The invention provides a medium transport unit including: an upstream route in which a medium is transported; a first switchback route arranged on the downstream side of the upstream route; a second switchback route arranged on the downstream side of the upstream route; a first guide route configured to guide the medium in the upstream route to the first switchback route; a second guide route configured to guide the medium in the upstream route to the second switchback route; a guide switch unit configured to selectively switch the route so that the medium transported through the upstream route is transported to one of the first guide route and the second guide route; a first discharge route configured to discharge the medium from the first switchback route; a second discharge route configured to discharge the medium from the second switchback route; and a downstream route passing between the first switchback route and the second switchback route and having an upstream end connected to a junction of downstream ends of the first discharge route and the second discharge route. 
     In this configuration, the routes arranged side by side are composed of three routes including the first switchback route, the second switchback route, and the downstream route, so that a reduction in size of the apparatus is enabled. 
     In the medium transport unit, preferably, at least one of a condition that a length of the first discharge route is shorter than a length of the first switchback route and a condition that a length of the second discharge route is shorter than the second switchback route is satisfied. 
     In this configuration, since at least one of the length of the first discharge route and the length of the second discharge route can be reduced, the reduction in size of the apparatus is enabled. 
     In the medium transport unit, preferably, at least one of a condition that a length of the first guide route is shorter than a length of the first switchback route and a condition that a length of the second guide route is shorter than the second switchback route is satisfied. 
     In this configuration, since the length of at least one of the first guide route and the second guide route can be reduced, the reduction in size of the apparatus is enabled. 
     Preferably, the medium transport unit further includes a skip route diverged from a midpoint of the upstream route and join to a midpoint of the downstream route to guide the medium in the upstream route to the downstream route without passing through the first guide route and the second guide route; and a skip switching unit configured to selectively switch the route of the medium in the upstream route so as to be transported toward one of a downstream end and the skip route of the upstream route. 
     In this configuration, by switching the skip switching unit to the skip route side, the medium in the upstream route can be rapidly transported to the downstream route without passing through the first guide route and the second guide route. 
     Preferably, in the medium transport unit, further includes an intermediate route connecting the downstream end of the upstream route and the upstream end of the downstream route, and the guide switch unit selectively switches the route so that the medium transported through the upstream route is transported to one of the first guide route, the second guide route, and the intermediate route. 
     In this configuration, by switching the guide switch unit to the intermediate route side, the medium in the upstream route can be rapidly transported to the upstream end of the downstream route through the intermediate route without passing through the first guide route and the second guide route. 
     Another advantage of some aspect of the invention is to provide a recording apparatus of the invention includes a recording unit configured to perform recording on a medium, and a post-processing unit configured to perform post-processing on the medium on which recording is performed by the recording unit, wherein the recording unit and the post-processing unit are coupled by the medium transport unit. 
     In this configuration, a medium on which the recording is performed by the recording unit is transported by the medium transporting unit, and is subjected to post-processing by the post-processing unit. 
     In the recording apparatus described above, the first switchback route and the second switchback route are each configured to be capable of receiving a medium having a maximum recordable size for the recording unit. 
     In this configuration, the medium having the maximum recordable size for the recording unit can be received by the first switchback route and the second switchback route. 
     Further advantage of some aspects of the invention is to provide the invention provides an image reading apparatus including: a reader configured to read an image on a medium; and the medium transporting unit described above, wherein the first switchback route and the second switchback route are each configured to be capable of receiving the medium having a maximum readable size for the reader. 
     In this configuration, the medium having the maximum readable size for the reader can be received by the first switchback route and the second switchback route. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
         FIG.  1    is a perspective view of a recording apparatus of an embodiment. 
         FIG.  2    is a view illustrating a structural frame format of the recording apparatus. 
         FIG.  3    is a view illustrating a structural frame format of a medium transport unit. 
         FIGS.  4 A to  4 C  are schematic drawings illustrating states of transporting a print sheet with the medium transport unit. 
         FIGS.  5 A and  5 B  are schematic drawings illustrating states of transporting a print sheet with the medium transport unit. 
         FIG.  6    is a view illustrating a structural frame format of an image reading apparatus. 
         FIGS.  7 A to  7 C  are structural frame formats illustrating a first switchback route and a second switchback route. 
         FIG.  8    is a view illustrating a structural frame format of the medium transport unit. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     An embodiment of a recording apparatus will be described below with reference to the drawings. 
     As illustrated in  FIG.  1   , a recording apparatus  11  includes a printer unit  12  as a recording unit, a scanner unit  13  arranged on the printer unit  12 , an automatic paper-feeding apparatus  14  arranged on the scanner unit  13 , a medium transport unit  15  arranged on a side portion of the printer unit  12 , and a finisher  16  as a post-processing unit arranged in the medium transport unit  15  on a side portion opposite to the side where the printer unit  12  is provided. An operating unit  17  configured to perform various operations on the recording apparatus  11  is provided on the printer unit  12  at a position adjacent to the scanner unit  13 . 
     As illustrated in  FIG.  2   , the printer unit  12  includes a medium transporting channel  20  in which a print sheet P as an example of the medium is transported, and a transport unit  21  including a plurality of rollers (roller pairs) and configured to transport the print sheet P along the medium transporting channel  20 . The printer unit  12  includes a supporting base  22  configured to support a print sheet P from a lower side in a vertical direction Z and a recording unit  23  configured to print (record) an image on the print sheet P supported by the supporting base  22  accommodated therein. 
     The printer unit  12  transports the print sheet P along the top of the supporting base  22  and the medium transporting channel  20  in an orientation that a width direction X of the print sheet P corresponds to the direction orthogonal to a paper plane of  FIG.  2    and a direction intersecting the width direction X corresponds to a transporting direction. The recording unit  23  is provided with a line head as a liquid ejection head capable of ejecting ink over the substantially entire area in the width direction X which intersects the transporting direction of the print sheet P simultaneously at a lower portion thereof, and is configured to print an image by ejecting ink from an upper side in the vertical direction Z toward the print sheet P transported on the supporting base  22  and causing the ink to adhere thereto. 
     The printed print sheet P is transported from the recording unit  23  to the medium transport channel  20  by a paper discharge roller pair  24  and other plurality of transport roller pairs  25  and is discharged from a medium discharge port  26  provided at a downstream end of the medium transport channel  20 . The print sheets P discharged from the medium discharge port  26  drop and are mounted on a mounting base  27  arranged on an upper side of the recording unit  23  in the vertical direction Z in a stacked manner as indicated by two-dot chain lines in  FIG.  2   . In other words, the mounting base  27  sequentially receives and supports printed print sheets P discharged and dropping from the medium discharge port  26 . 
     As illustrated in  FIG.  1    and  FIG.  2   , the mounting base  27  has a substantially rectangular plate shape, and is inclined so as to increase in height as it proceeds to a discharging direction Y of the print sheets P. An upper surface of the mounting base  27  corresponds to an inclined mounting surface  28 , and print sheets P are mounted on the mounting surface  28 . A protruding portion  29  extending in the discharging direction Y is formed on the mounting surface  28  substantially at a center in the width direction X of the print sheet P. 
     The print sheets P mounted on the mounting surface  28  slip downward in an opposite direction to the discharging direction Y along an inclination of the mounting surface  28  and are positioned by coming into contact at an end thereof opposite to the discharging direction Y side with a vertical side wall  30  provided on a lower side of the medium discharge port  26  of the printer unit  12  as indicated by the two-dot chain lines in  FIG.  2   . The discharging direction Y of the print sheet P is inclined at an angle larger than that of the mounting surface  28  with respect to a horizontal plane. 
     As illustrated in  FIG.  2   , the medium transport channel  20  in this embodiment includes a medium discharge channel  34  configured to transport the print sheet P from the recording unit  23  to the medium discharge port  26  and a medium supply channel configured to supply the print sheet P to the recording unit  23 , and the medium supply channel includes a first medium supply channel  31 , a second medium supply channel  32 , and a third medium supply channel  33 . 
     The medium discharge channel  34  includes a curved channel  34 A and a straight channel  34 B. The medium discharge channel is curved to cause the print sheet P to curve with a recording surface of the print sheet P printed by the recording unit  23  facing inward during the transport of the print sheet P printed by the recording unit  23  to the medium discharge port  26 . The straight channel  34 B transports the print sheet P from the curved channel  34 A toward the medium discharge port  26  in one direction. 
     The medium discharge channel  34  functions as a curving and reversing route configured to reverse the print sheet P from a state in which the recording surface thereof faces upward to a state in which the recording surface faces downward in the vertical direction by transporting the print sheet P in the curved channel  34 A and the straight channel  34 B. Therefore, the print sheet P passes through the medium discharge channel  34 , which functions as the curving and reversing route, whereby the recording surface thereof faces the mounting surface  28  of the mounting base  27 , and the print sheet P is discharged from the medium discharge port  26  onto the mounting base  27  located above the recording unit  23 . 
     The transporting direction of the print sheet P, which is a direction in which the print sheet P is transported in the straight channel  34 B in the medium discharge channel  34  provided in the medium transport channel  20  is one direction that the straight channel  34 B has. In this embodiment, the one direction is determined as an upward inclined direction which rises toward the medium discharge port  26 . Therefore, the inclined direction of the straight channel  34 B (one direction) corresponds to the discharging direction Y of the print sheet P discharged from the medium discharge port  26 . 
     In the first medium supply channel  31 , the print sheet P inserted from an insertion port  36  exposed when a cover  35  provided on one side surface of the printer unit  12  is opened is transported to the recording unit  23 . In other words, the print sheet P inserted into the insertion port  36  is pressed against a first drive roller  38   a  by a hopper  37 , is transported by a rotation of the first drive roller  38   a , then is pinched between the first drive roller  38   a  and a first driven roller  38   b , and then is transported toward the recording unit  23  by the rotation of the first drive roller  38   a.    
     The second medium supply channel  32  includes a sheet cassette  39  provided in a bottom portion, which corresponds to a lower side of the printer unit  12  in an insertable/withdrawable manner. The print sheets P mounted in the sheet cassette  39  in a stackable manner are transported to the recording unit  23 . In other words, an uppermost print sheet P from the print sheets P mounted in the sheet cassette  39  in a stacked manner is fed by a pickup roller  40 , is separated into a piece by a separation roller pair  41 , then is pinched between a second drive roller  42   a  and a second driven roller  42   b , and then is transported toward the recording unit  23  by a rotation of the second drive roller  42   a.    
     In the third medium supply channel  33 , in the case where both side printing, which is a printing option that prints images on both sheet surfaces (paper surfaces) of the print sheet P, is performed, the print sheet P whereof printing by the recording unit  23  on one sheet surface is terminated is transported again to the recording unit  23 . In other words, a divergent transport channel  44  is provided on the downstream side of the recording unit  23  in the transporting direction of the print sheet P. The divergent transport channel  44  is diverged from the medium discharge channel  34  upon an operation of a divergent mechanism  43  provided at the middle of the medium discharge channel  34  is provided. The divergent transport channel  44  is provided with a divergent transport channel roller pair  45  configured to be capable of rotating both in a forward direction and a reverse direction on the downstream side of the divergent mechanism  43 . 
     The print sheet P printed on one of the sheet surfaces on one side is transported from the recording unit  23  toward the mounting base  27  once to the divergent transport channel  44  by the divergent transport channel roller pair  45  rotating in the forward direction for the both side printing. At this time, a part Pe of the print sheet P transported to the divergent transport channel  44  on a leading end side in the transporting direction thereof projects from the medium discharge port  26 . Therefore, the position of projection of the print sheet P is set so as not to come into contact with the print sheets P mounted on the mounting base  27  in a stacked manner when projected. 
     Subsequently, the print sheet P transported to the divergent transport channel  44  is transported reversely in the divergent transport channel  44  from the mounting base  27  side toward the recording unit  23  by the divergent transport channel roller pair  45  rotating in the reverse direction. At this time, the print sheet P transported in the reverse direction is transported to the third medium supply channel  33  and is transported toward the recording unit  23  by the plurality of transport roller pairs  25 . The print sheet P is transported to the third medium supply channel  33  and hence is reversed so that the sheet surface which is not printed yet faces the recording unit  23 . Then, the reversed print sheet P is pinched between the third drive roller  46   a  and the third driven roller  46   b , and is transported toward the recording unit  23  by a rotation of the third drive roller  46   a.    
     The print sheet P transported in the respective medium supply channels toward the recording unit  23  is transported to a lining-up roller pair  47  disposed on the upstream side of the recording unit  23  in the transporting direction, and then comes into abutment at a leading edge thereof with the lining-up roller pair  47  which has stopped rotating. An inclination of the print sheet P with respect to the transporting direction is corrected (skew correction) by the state in which the print sheet P is in abutment with the lining-up roller pair  47  as described above. The print sheet P corrected in inclination is lined up and is transported toward the recording unit  23  by a subsequent rotation of the lining-up roller pair  47 . 
     The print sheet P transported toward the recording unit  23  by the lining-up roller pair  47  is transported in a state of facing the recording unit  23  by a paper feed roller pair  48  disposed on the upstream side of the recording unit  23  in the transporting direction of the print sheet P, and the paper discharge roller pair  24  and the transport roller pairs  25  disposed on the downstream side thereof in the transporting direction. Ink is ejected onto the transported print sheet P and from the recording unit  23  facing thereto to perform printing. 
     As illustrated in  FIG.  2   , a liquid storage unit  50  configured to store ink to be supplied to the recording unit  23  provided in the printer unit  12 . In other words, the liquid storage unit  50  supplies ink stored therein to the recording unit  23  via an ink supply channel, which is not illustrated, formed of a tube or the like. The recording unit  23  ejects the supplied ink to print an image or the like on the print sheet P. In this embodiment, the liquid storage unit  50  is arranged on an upper side of the print sheet P mounted on the mounting base  27  in the vertical direction Z. The liquid storage unit  50  is arranged so as to cover at least part of the medium discharge channel  34  when viewing from above in the vertical direction Z. 
     In other words, the upper side of the medium discharge channel  34 , which is a curving and reversing route, has an inclined shape directed in one direction formed by the straight channel  34 B continuing from the curved channel  34 A. Therefore, a space  12 S is formed in the printer unit  12  on an upper side of a portion from above the curved channel  34 A to the medium discharge port  26  of the straight channel  34 B having the inclined shape. 
     In this embodiment, the space  12 S is formed in the printer unit  12  so as to cover the medium discharge channel  34  in the width direction X when viewing from above. The liquid storage unit  50  is arranged in the space  12 S so as to cover at least part of the medium discharge channel  34  when viewing from above. In this embodiment, the liquid storage unit  50  is arranged so as to cover the entire part of the medium discharge channel  34  in the width direction X when viewing from above. 
     A transport roller pair  25   a  located on the downstream-most side of the medium discharge channel  34  in the transporting direction of the print sheet P among the plurality of transport roller pairs  25  which function as discharge rollers provided in the medium discharge channel  34 , is provided in the space  12 S at a position overlapping with the liquid storage unit  50  when viewing from a horizontal direction. 
     In addition, in the space  12 S, blast units  57  are provided in a space other than the space occupied by the liquid storage unit  50  at positions on the downstream side of the medium discharge port  26  in the discharging direction Y of the print sheet P. The blast units  57  are configured to blast air in a direction of pressing the print sheet P discharged from the medium discharge port  26  against the mounting surface  28 . The blast unit  57  includes a rotary fan  58 , and is provided at a position overlapping with the liquid storage unit  50  when viewing from the horizontal direction. 
     In this embodiment, a pair of the blast units  57  are provided in the width direction X of the print sheet P so that air-outlet ports thereof oppose both ends of the print sheet P in the width direction X with the protruding portion  29  (see  FIG.  1   ) on the mounting surface  28  interposed there between at a center. A configuration in which only one blast unit  57  is provided and the air-outlet port thereof has a shape continuing in the width direction X of the print sheet P is also applicable. 
     The liquid storage unit  50  includes ink cartridges  51 ,  52 ,  53 , and  54 , which correspond to liquid storage members configured to store a plurality of types (four colors in this case) of ink respectively, and a frame member  55  which allows the respective ink cartridges  51 ,  52 ,  53 , and  54  to be mounted thereon. The ink cartridges  51 ,  52 ,  53 , and  54  each are formed into a substantially rectangular parallelepiped shape having a longitudinal direction, and the frame member  55  has a box shape having an opening on one surface thereof. The ink cartridges  51 ,  52 ,  53 , and  54  are configured to be mounted in the frame member  55  via the opening thereof in an insertable/withdrawable manner. The inserting/withdrawing direction corresponds to the longitudinal direction of the ink cartridges. 
     In this embodiment, the inserting/withdrawing directions of the ink cartridges  51 ,  52 ,  53 , and  54  are directions along the width direction X. Therefore, the printer unit  12  includes an aperture, which is not illustrated, which exposes the opening of the frame member  55  when viewing from the width direction X, and a storage unit cover  56  (see  FIG.  1   ) which is capable of opening and closing the aperture. For example, a user of the recording apparatus  11  is allowed to expose the aperture, which is not illustrated, by opening the storage unit cover  56  (see  FIG.  1   ), and insert and withdraw the ink cartridges  51 ,  52 ,  53 , and  54  with respect to the frame member  55  via the exposed aperture along the width direction X. 
     In this embodiment, the short direction, the longitudinal direction, and a thickness direction of each of the ink cartridges  51 ,  52 ,  53 , and  54  are oriented in the vertical direction Z, the width direction X, and the horizontal direction which extends along the discharging direction Y, respectively, in a state in which the ink cartridges  51 ,  52 ,  53 , and  54  are mounted in the frame member  55 . The ink cartridges  51 ,  52 ,  53 , and  54  have the same length in the short direction (vertical direction Z) and are mounted in the frame member  55  in a line in the thickness direction. 
     The ink cartridge  54  out of the ink cartridges  51 ,  52 ,  53 , and  54  is an ink cartridge which stores ink having the highest injection frequency from the recording unit  23  (for example, black) and is arranged at the farthest position from the medium discharge port  26  on the opposite side to the mounting base  27 . The ink cartridge  54  is thicker than other ink cartridges  51 ,  52 , and  53  and is capable of storing a larger amount of liquid than the storage amounts of ink in other ink cartridges  51 ,  52 , and  53 . 
     As illustrated in  FIG.  2   , a rectangular plate-shaped channel forming member  61  is arranged between the recording unit  23  and the mounting base  27  in the printer unit. The channel forming member  61  and the mounting base  27  form part of the third medium supply channel  33 , which corresponds to a reversing route configured to reverse the print sheet P. In other words, a lower surface of the mounting base  27  and an upper surface of the channel forming member  61  form the third medium supply channel  33 . The channel forming member  61  is inclined so as to be increased in height as it proceeds to the discharging direction Y. 
     A communication route  62  diverged from an upstream end of the curved channel  34 A of the medium discharge channel  34  and extending to the medium transport unit  15  is provided in the printer unit  12 . The communication route  62  is provided with a communication transport roller pair  63  configured to transport the print sheet P in the communication route  62  toward the medium transport unit  15 . A switching flap  64  is provided at a diverging portion between the medium discharge channel  34  and the communication route  62 . The switching flap  64  is capable of switching the route of the print sheet P being transported in the medium discharge channel  34  either toward the curved channel  34 A or toward the communication route  62 . 
     The switching flap  64  is configured to be displaced between a position for introducing the print sheet P having been printed by the recording unit  23  and being transported along the medium discharge channel  34  toward the curved channel  34 A (a position indicated by a solid line in  FIG.  2   ) and a position for introducing the print sheet P toward the communication route  62  (a position indicated by a two-dot chain line in  FIG.  2   ). 
     The recording apparatus  11  includes a control unit  65  configured to control the entire recording apparatus  11  in an overall manner. 
     Next, a configuration of the medium transport unit  15  will be described in detail. 
     As illustrated in  FIG.  3   , the medium transport unit  15  provided with a main body case  70  having parallelepiped shape. An upstream route  71  is provided on an upper portion of the main body case  70  so as to extend from the printer unit  12  side, which corresponds to the upstream side, toward the finisher  16 , which corresponds to the downstream side. The upstream route  71  is connected at an upstream end thereof to a downstream end of the communication route  62 , and the print sheet P transported from the communication route  62  is transported there through. 
     A downstream end of the upstream route  71  is curved downward. A skip route  72  is diverged from a beginning of the curve, which corresponds to the midpoint of the upstream route  71  and extends toward the finisher  16 . A skip flap  73 , which is an example of a skip switching unit configured to selectively switch the route so that the print sheet P in the upstream route  71  is transported either toward the downstream end of the upstream route  71  or toward the skip route  72  is provided at the diverging point to the upstream route  71  and the skip route  72 . 
     The skip flap  73  is configured to displace between a position for introducing the print sheet P in the upstream route  71  toward the downstream end of the upstream route  71  (a position indicated by a solid line in  FIG.  3   ) and a position for introducing the print sheet P toward the skip route  72  (a position indicated by a two-dot chain line in  FIG.  3   ). An upstream sensor  74  configured to detect an end of the print sheet P transported in the upstream route  71  is provided in the upstream route  71  at a position immediately upstream side of the skip flap  73 . 
     An upstream end of a first guide route  75 , an upstream end of a second guide route  76 , and an upstream end of an intermediate route  77  are connected to the downstream end of the upstream route  71 . The first guide route  75  is curved downward while extending from the downstream end of the upstream route  71  toward the finisher  16 . 
     The second guide route  76  is curved downward while extending toward the printer unit  12  from the downstream end of the upstream route  71 . The intermediate route  77  extends straight downward from the downstream end of the upstream route  71 , and is arranged between the first guide route  75  and the second guide route  76 . 
     A pair of guide flaps  78  as an example of a guide switch unit configured to selectively switch the route so that the print sheet P transported through the upstream route  71  is transported to one of the first guide route  75 , the second guide route  76 , and the intermediate route  77  is provided at the downstream end of the upstream route  71 . The pair of guide flaps  78  are configured to be displaced among a position for introducing the print sheet P in the upstream route  71  to the first guide route  75  (a position indicated by a solid line in  FIG.  3   ), a position for introducing the print sheet P to the second guide route  76  (a position indicated by a two-dot chain line in  FIG.  3   ), and a position for introducing the print sheet P to the intermediate route  77  (a position indicated by a dot-and-dash line in  FIG.  3   ). 
     An upstream end of a first switchback route  79  is connected to the downstream end of the first guide route  75 . Therefore, the first guide route  75  is configured to introduce the print sheet P in the upstream route  71  to the first switchback route  79  arranged on the downstream side of the upstream route  71 . The first switchback route  79  extends straight downward from the downstream end of the first guide route  75 . The first switchback route  79  is opened at a downstream end thereof, and is configured to be capable of receiving the print sheet P having a maximum printable (recordable) size for the recording unit  23  (see  FIG.  2   ). 
     An upstream end of a first discharge route  80  from which the print sheet P transported from the first guide route  75  to the first switchback route  79  is discharged is connected to the upstream end of the first switchback route  79 , and the downstream end of the first discharge route  80  is connected to the downstream end of the intermediate route  77  so as to join together. The first discharge route  80  has a semi-arc shape protruding toward the guide flaps  78 , which correspond to the upper side, and has a length shorter than the first switchback route  79 . 
     A first restriction flap  81  is provided at the downstream end of the first guide route  75 . The first restriction flap  81  allows a movement of the print sheet P from the first guide route  75  to the first switchback route  79 , but restricts the movement of the print sheet P from the first switchback route  79  to the first guide route  75 . The first restriction flap  81  is biased in the direction that closes the downstream end of the first guide route  75  constantly by a biasing force applied by a biasing member, which is not illustrated. 
     When the print sheet P is transported from the first guide route  75  to the first switchback route  79 , the first restriction flap  81  is displaced in the direction that opens the downstream end of the first guide route  75  against a biasing force applied by the biasing member, which is not illustrated, by a force that transports the print sheet P. When the print sheet P is transported from the first switchback route  79  toward the first guide route  75 , the print sheet P is introduced to the first discharge route  80  while being restricted to move toward the first guide route  75  by the first restriction flap  81 . 
     A first switchback roller pair  82  configured to be rotatable in both forward and reverse directions is provided in the first switchback route  79  at a position biased to the upstream end from a center portion. Therefore, the first switchback roller pair  82  is configured to be capable of transporting the print sheet P in the both forward and reverse directions. A first switchback sensor  83  is provided in the first switchback route  79  between the first switchback roller pair  82  and the first restriction flap  81 . The first switchback sensor  83  is configured to detect the end of the print sheet P being transported in the first switchback route  79 . 
     An upstream end of a second switchback route  85  is connected to the downstream end of the second guide route  76 . Therefore, the second guide route  76  is configured to introduce the print sheet P in the upstream route  71  to the second switchback route  85  arranged on the downstream side of the upstream route  71 . The second switchback route  85  extends straight downward from the downstream end of the second guide route  76 . The second switchback route  85  is opened at a downstream end thereof, and is configured to be capable of receiving the print sheet P having the maximum printable (recordable) size for the recording unit  23  (see  FIG.  2   ). 
     An upstream end of a second discharge route  86  from which the print sheet P transported from the second guide route  76  to the second switchback route  85  is discharged is connected to the upstream end of a second switchback route  85 , and the downstream end of the second discharge route  86  is connected to the downstream end of the intermediate route  77  so as to join together. The second discharge route  86  has a semi-arc shape protruding toward the guide flaps  78 , which correspond to the upper side, and has a length shorter than the second switchback route  85 . In this embodiment, the first switchback route  79  and the second switchback route  85  have the same length and the first discharge route  80  and the second discharge route  86  have the same length. 
     A second restriction flap  87  is provided at the downstream end of the second guide route  76 . The second restriction flap  87  allows a movement of the print sheet P from the second switchback route  85  to the second guide route  76 , but restricts the movement of the print sheet P from the second switchback route  85  to the second guide route  76 . The second restriction flap  87  is biased in the direction that closes the downstream end of the second guide route  76  constantly by a biasing force applied by a biasing member, which is not illustrated. 
     When the print sheet P is transported from the second guide route  76  to the second switchback route  85 , the second restriction flap  87  is displaced in the direction that opens the downstream end of the second guide route  76  against a biasing force applied by the biasing member, which is not illustrated, by a force that transports the print sheet P. In contrast, when the print sheet P is transported from the second switchback route  85  toward the second guide route  76 , the print sheet P is introduced to the second discharge route  86  while being restricted to move toward the second guide route  76  by the second restriction flap  87 . 
     A second switchback roller pair  88  configured to be rotatable in both forward and reverse directions is provided in the second switchback route  85  at a position biased to the upstream end from a center portion. Therefore, the second switchback roller pair  88  is configured to be capable of transporting the print sheet P in the both forward and reverse directions. A second switchback sensor  89  is provided in the second switchback route  85  between the second switchback roller pair  88  and the second restriction flap  87 . The second switchback sensor  89  is configured to detect the end of the print sheet P being transported in the second switchback route  85 . 
     The intermediate route  77 , the first discharge route  80 , and the second discharge route  86  are joined together at downstream ends thereof, and an upstream end of a downstream route  90  is connected to a junction G thereof. Therefore, the intermediate route  77  connects the downstream end of the upstream route  71  and the upstream end of the downstream route  90 . 
     The downstream route  90  extends straight downward from the junction G so as to pass between the first switchback route  79  and the second switchback route  85 , and then U-turns toward the finisher  16  so as to go around the lower side of the downstream end of the first switchback route  79 . Subsequently, the downstream route  90  extends straight upward along the finisher  16 , joins together with the downstream end of the skip route  72 , and is connected at a downstream end thereof to the finisher  16 . 
     As described above, the skip route  72  extending from the midpoint of the upstream route  71  curves gently upward as it proceeds to the downstream end thereof and joins at the downstream end thereof with a downstream end portion (midpoint) of the downstream route  90 . Therefore, the skip route  72  is capable of introducing the print sheet P in the upstream route  71  to the downstream route  90  without passing through the intermediate route  77 , the first discharge route  80 , and the second discharge route  86 . A plurality of transport roller pairs  91  capable of transporting the print sheet P are arranged in the upstream route  71 , the skip route  72 , and the downstream route  90  at proper intervals. 
     As illustrated in  FIG.  2    and  FIG.  3   , the plurality of transport roller pairs  91 , the first switchback roller pair  82 , the second switchback roller pair  88 , and the communication transport roller pair  63  are configured to be driven to rotate upon a transmission of a drive force from a motor  92  arranged in the main body case  70  via an electric clutch, which is not illustrated. In addition, the skip flap  73 , the pair of guide flaps  78 , and the switching flap  64  are configured to be displaced upon a transmission of a drive force from the motor  92  via the electric clutch, which is not illustrated. 
     The upstream sensor  74 , the first switchback sensor  83 , the second switchback sensor  89 , the motor  92 , and the above-described electric clutch (not illustrated) are electrically connected to the control unit  65 . The control unit  65  drives and controls the motor  92  and the above-described electric clutch (not illustrated) on the basis of signals transmitted from the upstream sensor  74 , the first switchback sensor  83 , and the second switchback sensor  89 . 
     The postprocessing to be performed by the finisher  16  includes sorting, folding, stapling, punching, and aligning that aligns the ends of the printed print sheets P sequentially transported from the medium transport unit  15 . A finisher configured to perform at least one of the above-described processes may also be provided. 
     An operation to be effected when reversing the print sheet P printed by the recording unit  23  and transporting the same to the finisher  16  with the medium transport unit  15  will be described below. 
     As illustrated in  FIG.  2    and  FIG.  3   , the print sheet P printed by the recording unit  23  is transported toward downstream along the medium discharge channel  34  in a state in which the recording surface (printing surface) faces upward. At this time, the switching flap  64  is displaced to a position for opening an upstream end side of the communication route  62 , whereby the print sheet P in the medium discharge channel  34  is introduced into the communication route  62  by the switching flap  64 . 
     The print sheet P introduced to the communication route  62  is transported by the communication transport roller pair  63  to the upstream route  71  of the medium transport unit  15  along the communication route  62 . In the description given below, P 1  is a first print sheet out of the print sheets P to be sequentially transported to the upstream route  71  and, in the same manner, P 2  is a second print sheet, P 3  is a third print sheet, and P 4  is a fourth print sheet. 
     As illustrated in  FIG.  3   , when the skip flap  73  is displaced to a position for closing the upstream end side of the skip route  72 , the first print sheet P 1  transported to the upstream route  71  is introduced to the downstream end of the upstream route  71  by the skip flap  73 . At this time, since the pair of guide flaps  78  are displaced to positions for introducing the print sheet P 1  in the upstream route  71  to the first guide route  75 , the print sheet P 1  in the upstream route  71  passes through the first guide route  75  and is transported to the first switchback route  79  as illustrated in  FIG.  4 A . 
     Subsequently, when the print sheet P 1  passes over the upstream route  71 , the second print sheet P 2  is transported to the upstream route  71 , and the pair of guide flaps  78  are displaced to positions for introducing the print sheet P 2  in the upstream route  71  to the second guide route  76 . Subsequently, as illustrated in  FIG.  4 B , the print sheet P 1  is transported to the first switchback route  79  by the first switchback roller pair  82  rotating forward, and when a trailing edge of the print sheet P 1  in a direction of travel is detected by the first switchback sensor  83 , the first switchback roller pair  82  is rotated reversely. At this time, the print sheet P 2  is transported from the upstream route  71  to the second guide route  76 . 
     Subsequently, as illustrated in  FIG.  4 C , when the print sheet P 2  passes over the upstream route  71 , the third print sheet P 3  is transported to the upstream route  71 , and the pair of guide flaps  78  are displaced to positions for introducing the print sheet P 3  in the upstream route  71  to the first guide route  75 . In contrast, when the first switchback roller pair  82  are rotated reversely, the print sheet P 1  in the first switchback route  79  passes through the first discharge route  80  and is transported to the downstream route  90 . In this transport process, the print sheet P 1  is reversed. At this time, the print sheet P 2  transported to the second guide route  76  is transported to the second switchback route  85  by the second switchback roller pair  88  rotating forward. 
     Subsequently, as illustrated in  FIG.  5 A , the print sheet P 2  is transported to the second switchback route  85  by the second switchback roller pair  88  rotating forward, and when a trailing edge of the print sheet P 2  in the direction of travel is detected by the second switchback sensor  89 , the second switchback roller pair  88  is rotated reversely. At this time, the print sheet P 3  is transported from the upstream route  71  to the first guide route  75 , and the print sheet P 1  is transported downstream side along the downstream route  90 . 
     Subsequently, as illustrated in  FIG.  5 B , when the print sheet P 3  passes over the upstream route  71 , the fourth print sheet P 4  is transported to the upstream route  71 , and the pair of guide flaps  78  are displaced to positions for introducing the print sheet P 4  in the upstream route  71  to the second guide route  76 . In contrast, when the second switchback roller pair  88  are rotated reversely, the print sheet P 2  in the second switchback route  85  passes through the second discharge route  86  and is transported to the downstream route  90 . In this transport process, the print sheet P 2  is reversed. 
     At this time, the print sheet P 3  transported to the first guide route  75  is transported to the first switchback route  79  by the first switchback roller pair  82  rotating forward. Furthermore, at this time, the print sheet P 1  is transported further downstream side along the downstream route  90 . 
     In this manner, the print sheet P printed by the recording unit  23  is reversed by the medium transport unit  15  and is sequentially transported to the finisher  16  in a state in which the recording surface faces downward. Subsequently, the print sheets P are sorted, folded, stapled, punched or aligned by the finisher  16 . 
     In the case where the print sheet P printed by the recording unit  23  is not reversed by the medium transport unit  15 , but is transported to the finisher  16  as illustrated in  FIG.  3   , transport of the print sheet P is performed in a state in which the pair of guide flaps  78  are displaced to positions for introducing the print sheet P in the upstream route  71  to the intermediate route  77 . In other words, the print sheet P transported to the upstream route  71  is transported to the finisher  16  passing through the intermediate route  77  and the downstream route  90 . In this configuration, even a printed print sheet P which does not have to be reversed is transported along the intermediate route  77  and the downstream route  90 , so that a natural drying time for the paper P is ensured. 
     In addition, in the case where the print sheet P printed by the recording unit  23  is rapidly transported to the finisher  16  by the medium transport unit  15  as illustrated in  FIG.  3   , transport of the print sheet P is performed in a state in which the skip flap  73  is displaced to the position for opening the upstream end side of the skip route  72 . In other words, the print sheet P transported to the upstream route  71  is transported to the finisher  16  passing through the skip route  72  and a downstream end portion (part) of the downstream route  90 . In this case, since the skip route  72  simply curves gently upward toward the downstream end thereof, this configuration is convenient for the case where the medium can hardly be curved significantly such as a thick paper. 
     According to the embodiment described in detail thus far, the following advantageous effects are achieved. 
     (1) In the medium transport unit  15 , the downstream route  90  passes between the first switchback route  79  and the second switchback route  85 , and the upstream end thereof is connected to the junction G of the downstream ends of the first discharge route  80  and the second discharge route  86 . In addition, the length of the first discharge route  80  is shorter than the length of the first switchback route  79 , and the length of the second discharge route  86  is shorter than the length of the second switchback route  85 . Therefore, since the lengths of the first discharge route  80  and the second discharge route  86  may be reduced compared with those in the related art, and hence the medium transport unit  15  can be reduced in size. 
     (2) The medium transport unit  15  includes the skip route  72  diverged from the midpoint of the upstream route  71 , joined to the downstream end portion of the downstream route  90 , and configured to introduce the print sheet P in the upstream route  71  to the downstream end of the downstream route  90 , and the skip flap  73  configured to selectively switch the route so that the print sheet P in the upstream route  71  is transported either toward the downstream end of the upstream route  71  or toward the skip route  72 . 
     Therefore, by switching the skip flap  73  toward the skip route  72  side, the print sheet P in the upstream route  71  can be transported rapidly through the skip route  72  to the downstream end portion of the downstream route  90  without passing through the intermediate route  77 , the first discharge route  80 , and the second discharge route  86 . 
     (3) The medium transport unit  15  is provided with the intermediate route  77  configured to connect the downstream end of the upstream route  71  and the upstream end of the downstream route  90 , and the pair of guide flaps  78  are configured to selectively switch the route so that the print sheet P transported through the upstream route  71  is transported to one of the first guide route  75 , the second guide route  76 , and the intermediate route  77 . Therefore, by switching the pair of guide flaps  78  toward the intermediate route  77 , the print sheet P in the upstream route  71  can be rapidly transported to the upstream end of the downstream route  90  through the intermediate route  77  without passing through the first guide route  75  and the second guide route  76 . 
     (4) In the medium transport unit  15 , the length of the first guide route  75  is shorter than the length of the first switchback route  79 , and the length of the second guide route  76  is shorter than the length of the second switchback route  85 . Therefore, since the lengths of the first guide route  75  and the second guide route  76  may be reduced compared with those in the related art, the medium transport unit  15  can be reduced in size. 
     (5) The recording apparatus  11  includes the recording unit  23  configured to perform printing on the print sheet P, and the medium transport unit  15 , and the first switchback route  79  and the second switchback route  85  are each configured to be capable of receiving the print sheet P having the maximum printable size for the recording unit  23 . Therefore, the print sheet P can be reliably received by the first switchback route  79  and the second switchback route  85  as long as printing on the print sheet P by the recording unit  23  is possible. 
     (6) The recording unit  23  includes a line head capable of ejecting ink on the print sheet P transported at a high speed simultaneously over the substantially entire area in the width direction X at a lower portion thereof. Therefore, the high-speed printing is enabled. However, since the print sheet P absorbs ink over a wide surface area in a short time, the print sheet P tends to be curled in a wave shape in cross section. 
     If the print sheet P is curled, the print sheet P may jam in the course of the transporting route or the post-processing such as sorting and folding may not be performed in the finisher  16 . In this embodiment, with the provision of the medium transport unit  15 , the printed print sheet P is dried while being transported in the transporting route provided in the medium transport unit  15 , and curled shape of the print sheet P is disappeared and an original shape may be restored. 
     Modification 
     The above-described embodiment may be modified as follows. 
     As illustrated in  FIG.  6   , the medium transport unit  15  may be provided on an image reading apparatus  100  configured to read an image on the print sheet P. In other words, the image reading apparatus  100  includes a scanner unit  101  configured to read the image on the print sheet P, the medium transport unit  15  arranged on the side portion of the scanner unit  101 , and the finisher  16  arranged on the medium transport unit  15  on a side portion provided on a side opposite to the scanner unit  101  side. The scanner unit  101  includes a tray  102  on which print sheets P are set, a transporting route  103  configured to transport the print sheets P set on the tray  102  to the upstream route  71  (see  FIG.  3   ) of the medium transport unit  15 , and a no-color transparent glass plate  104  arranged at a midpoint of the transporting route  103  and forming a read surface  104   a  where an image on the print sheet P is read. A reader  105  configured to read the image on the print sheet P passing over the read surface  104   a  through the glass plat  104  is arranged at a position right under the glass plate  104 . The transporting route  103  includes a paper feed roller  106  configured to feed the print sheet P set on the tray  102 , a paper feed roller pair  107  configured to feed the print sheet P fed by the paper feed roller  106  onto the read surface  104   a , and a paper discharge roller pair  108  configured to discharge the print sheet P on the read surface  104   a  to the medium transport unit  15 . The first switchback route  79  and the second switchback route  85  of the medium transport unit  15  are opened at the downstream ends thereof so as to be capable of receiving the print sheet P having a maximum readable size for the reader  105 . In this configuration, the print sheet P can be reliably received by the first switchback route  79  and the second switchback route  85  as long as the print sheet P can be read by the reader  105  is possible. In addition, the image reading apparatus  100  configured as described above is convenient in the case of, for example, reading a plurality of the print sheets P (originals) which are stapled, and then stapling the print sheets P again. In other words, by removing the staple once and setting the plurality of print sheets P on the tray  102  of the image reading apparatus  100 , the plurality of print sheets P are sequentially transported to the finisher  16  by the medium transport unit  15  after the images on the plurality of print sheets P have sequentially been read by the reader  105 , and then are stapled again. 
     In the medium transport unit  15 , the intermediate route  77  may be omitted. 
     In the medium transport unit  15 , the skip route  72  may be omitted. 
     In the medium transport unit  15 , the length of the first discharge route  80  may be longer than the length of the first switchback route  79 . 
     In the medium transport unit  15 , the length of the second discharge route  86  may be longer than the length of the second switchback route  85 . 
     In the medium transport unit  15 , the length of the first guide route  75  may be longer than the length of the first switchback route  79 . 
     In the medium transport unit  15 , the length of the second guide route  76  may be longer than the length of the second switchback route  85 . 
     In the medium transport unit  15 , part of the print sheet P may be protruded from opened downstream ends (lower ends) of the first switchback route  79  and the second switchback route  85  when the print sheet P is received in the first switchback route  79  and the second switchback route  85 . 
     In the medium transport unit  15 , the length of the first switchback route  79  and the second switchback route  85  may be different from each other. 
     In the medium transport unit  15 , the first discharge route  80  and the second discharge route  86  may be different lengths from each other. 
     The first switchback route  79  and the second switchback route  85  each may be configured to include a space area. The first switchback route  79  and the second switchback route  85  illustrated in  FIG.  7 A  each include guide surfaces  110   a  and  110   b  facing each other on the upstream side of the first switchback roller pair  82  and the second switchback roller pair  88  and have no guide surface on the downstream side thereof but have a space area. When the first switchback roller pair  82  and the second switchback roller pair  88  pinch the print sheet P and rotate in the forward direction or in the reverse direction, the print sheet P is transported in a state in which the downstream side of the print sheet P hangs therefrom. In this configuration, a member having the guide surface is not required, and hence the medium transport unit  15  may be reduced in size. 
     The first switchback route  79  and the second switchback route  85  each may be configured to include a curved route. The first switchback route  79  and the second switchback route  85  illustrated in  FIG.  7 B  each include guide surfaces  111   a  and  111   b  curved and facing each other on the downstream side of the first switchback roller pair  82  and the second switchback roller pair  88 . When the first switchback roller pair  82  and the second switchback roller pair  88  pinch the print sheet P and rotate in the forward direction or in the reverse direction, the print sheet P is transported in a state in which the downstream side of the print sheet P is curved. In this configuration, the length of the medium transport unit  15  in vertical direction of the drawing may be reduced. 
     The first switchback route  79  and the second switchback route  85  may each have a roller at a downstream end thereof to cause the downstream side of the print sheet to curve along an outer peripheral surface of the roller. The first switchback route  79  and the second switchback route  85  in  FIG.  7 C  include guide surfaces  112   a  and  112   b  extending downward and facing each other on the downstream side of the first switchback roller pair  82  and the second switchback roller pair  88 , and each include a roller  114  located at a position below the guide surface  112   b  and configured to be rotatable, and guide surface  113  connected to the guide surface  112   a  and curved along the outer peripheral surface of the roller  114 . 
     As illustrated in  FIG.  7 C , when the first switchback roller pair  82  and the second switchback roller pair  88  each pinch the print sheet P and rotate in a direction in which the print sheet P moves to the downstream side, the print sheet P is transported with the downstream side thereof being wound around the outer peripheral surface of the roller  114 . When the first switchback roller pair  82  and the second switchback roller pair  88  each rotate in a direction in which the print sheet P moves toward the upstream side, the print sheet P is transported with the downstream side thereof being wound around the outer peripheral surface of the roller  114 . 
     A configuration in which the roller  114  is rotated in conjunction with timing of rotation of each of the first switchback roller pair  82  and the second switchback roller pair  88  is also applicable. In this configuration, the length of the medium transport unit  15  in a lateral direction of the drawing may be reduced. 
       FIG.  8    is a view illustrating a structural frame format of a medium transport unit  15   a  when viewing in the width direction X. The first guide route  75  and the second guide route  76  illustrated in  FIG.  3    are arranged so as to overlap entirely with the first discharge route  80  and the second discharge route  86 , respectively, in the vertical direction Z. However, a first guide route  121  and the second guide route  122  may be arranged so as to partly overlap with a first discharge route  125  and a second discharge route  126 , respectively, in the vertical direction Z as illustrated in  FIG.  8   . 
     An upstream route  120  is arranged from the printer unit  12  to the medium transport unit  15   a , and is arranged so as to be inclined downward as it proceeds to the downstream side in the transporting direction. The upstream route  120  is diverged to the first guide route  121  and the second guide route  122  at a diverging point F 1 , which corresponds to a downstream end of the upstream route  120 . 
     The first guide route  121  is diverged to a first switchback route  123  and the first discharge route  125  at a diverging point F 2 , which corresponds to a downstream end of the first guide route  121 . In the same manner, the second guide route  122  is diverged to a second switchback route  124  and the second discharge route  126  at a diverging point F 3 , which corresponds to a downstream end of the second guide route  122 . The first discharge route  125  and the second discharge route  126  join together on the downstream side thereof at a junction G 1  and are connected to a downstream route  127 . 
     The upstream route  120 , the first guide route  121 , the second guide route  122 , the first discharge route  125 , the second discharge route  126 , and the downstream route  127  are each provided with a transport roller pair  130  configured to transport a print sheet to the downstream side thereof. The first switchback route  123  and the second switchback route  124  are provided with switchback roller pairs  131  and  132  configured to be capable of transporting the print sheet while switching the transporting direction to the downstream side or to the upstream side, respectively. 
     A guide flap  150  that functions as a guide switch unit is provided at the diverging point F 1  so as to be pivotable as indicated by a solid line and a broken line to guide a print sheet (not illustrated) transported from the upstream side to the first guide route  121  or the second guide route  122 . 
     A first restriction flap  151  and a second restriction flap  152  are provided at the diverging points F 2  and F 3 , respectively. The first restriction flap  151  and the second restriction flap  152  are biased constantly in directions that closes the downstream ends of the first guide route  121  and the second guide route  122 , respectively, by a biasing force applied by a biasing member, which is not illustrated. 
     When the print sheet is transported from the first guide route  121  to the first switchback route  123 , the first restriction flap  151  is displaced in a direction that opens the downstream end of the first guide route  121  against a biasing force applied by the biasing member by a force that transports the print sheet. In contrast, when the print sheet is transported from the first switchback route  123  toward the first guide route  121 , the print sheet is introduced into the first discharge route  125  while restricting the print sheet from moving to the first guide route  121  by the first restriction flap  151 . 
     In the same manner, when the print sheet is transported from the second guide route  122  to the second switchback route  124 , the second restriction flap  152  is displaced in the direction that opens the downstream end of the second guide route  122  against a biasing force applied by the biasing member by the force that transports the print sheet. In contrast, when the print sheet is transported from the second switchback route  124  toward the second guide route  122 , the print sheet is introduced to the second discharge route  126  while restricting the print sheet from moving to the second guide route  122  by the second restriction flap  152 . 
     The first guide route  121  has a curved shape protruding upward. An upper portion of the second guide route  122  has a curved shape protruding toward the finisher  16 , and a lower portion of the second guide route  122  has a curved shape protruding toward the printer unit  12 . In other words, the second guide route  122  is arranged so that the shape viewed from the width direction X is curved into an S shape. 
     The first guide route  121  is arranged so as to overlap partly with the first discharge route  125  in the vertical direction Z. In the same manner, the second guide route  122  is arranged so as to overlap partly with the second discharge route  126  in the vertical direction Z. 
     The diverging point F 1  is located at a position biased to the printer unit  12  above the position of the junction G 1 . 
     The diverging point F 2  is located at a position above the diverging point F 3  on the finisher  16  side. 
     Therefore, as indicated by a dot-and-dash line J 1  that connects the diverging point F 1  and the junction G 1  and a two-dot chain line J 2  that connects the diverging point F 2  and the diverging point F 3 , a configuration of a closed circular route formed by the first guide route  121 , the second guide route  122 , the first discharge route  125 , and the second discharge route  126  has an inclined shape in the vertical direction Z as a whole. 
     The first switchback route  123  is formed on the downstream side of the diverging point F 2 , and includes guide surfaces  123   a  and  123   b  facing each other and guide surfaces  123   c ,  123   d , and  123   e  formed continuously on the downstream side of the guide surface  123   a . The surface facing the guide surfaces  123   c ,  123   d , and  123   e  is not provided, the guide surfaces  123   c  and  123   d  are opened on the printer unit  12  side, and the guide surface  123   e  is opened on the upper side. The length of the first switchback route  123  is longer than the lengths of the first guide route  121  and the first discharge route  125 . 
     The print sheet is guided by the guide surfaces  123   a  and  123   b  facing each other in the upper portion of the first switchback route  123 , and is guided by the guide surfaces  123   c ,  123   d , and  123   e  having different angle of inclination in the vertical direction Z in the lower portion of the first switchback route  123 . Therefore, the print sheet transported by the switchback roller pair  131  is bent as indicated by a broken line. 
     The second switchback route  124  is formed on the downstream side of the diverging point F 3  and includes guide surfaces  124   a  and  124   b  facing each other, and the print sheet transported by a switchback roller pair  132  is guided thereby. The print sheet longer than the guide surfaces  124   a  and  124   b  is bent as indicated by a broken line along an inner side surface  140  and an inner bottom surface  141  of a main body case  70   a  in a state of being pinched by the switchback roller pair  132 . Therefore, when a long print sheet is transported by the switchback roller pair  132 , the inner side surface  140  and the inner bottom surface  141  function as the guide surfaces in the second switchback route  124 . 
     The downstream route  127  passes from the junction G 1  between the first switchback route  123  and the second switchback route  124 , and U-turns upward so as to go around the lower side of the first switchback route  123 . The downstream route  127  extends straight upward along an inner side surface  142  of the main body case  70   a , protrudes toward the printer unit  12  and curved, and then is arranged so as to be directed toward the finisher  16 . 
     The first switchback route  123 , the second switchback route  124 , and the downstream route  127  include curved portions W 1 , W 2 , and W 3  protruding in the same direction (toward the finisher  16 ). 
     The printer unit  12 , the finisher  16 , and an enclosure (housing) of the medium transport units  15  and  15   a  may be configured integrally or may be configured to be separable. 
     With the configuration of the transporting route provided in the medium transport unit  15   a  as described with reference to  FIG.  8    thus far, the length of the transporting route in the vertical direction Z and the transporting direction are reduced to restrict an increase in size of the recording apparatus. 
     The medium may be only the print sheets P, but also cloth and plastic films. 
     In the embodiment described above, the recording apparatus  11  may be a fluid ejecting apparatus configured to perform recording by ejecting and discharging fluids other than ink (including liquids, liquid-state materials formed by a liquid with particles of a functional material dispersed or mixed therein, flowing-state materials such as gel, and solids that can be flowed and ejected as a fluid). For example, a liquid-state material ejecting apparatus configured to perform recording by ejecting a liquid-state material including materials such as electrode materials or color materials (pixel materials) used for manufacturing liquid-crystal displays, EL (electro luminescence) displays, and surface-emitting displays in a form of dispersion or dissolution. Also, a flowing-state material ejecting apparatus configured to eject a flowing-state material such as gel (for example, physical gel). 
     The invention may be applied to one of these fluid ejection apparatuses. The term “fluid” in the specification is an idea not including fluids composed only of gas, and the fluid includes, for example, liquids (including inorganic solvent, organic solvent, solution, liquid-state resin, liquid-state metal (metallic melt) and the like), liquid-state materials and flowing-state materials. 
     This application is a continuation of U.S. patent application Ser. No. 16/510,493, filed Jul. 12, 2019, which is a continuation of U.S. patent application Ser. No. 15/828,048, filed Nov. 30, 2017 and granted as U.S. Pat. No. 10,391,791 on Aug. 27, 2019, which is a continuation of U.S. patent application Ser. No. 15/237,366, filed Aug. 15, 2016 and granted as U.S. Pat. No. 9,855,770 on Jan. 2, 2018, which is a continuation of U.S. patent application Ser. No. 14/920,639, filed Oct. 22, 2015, which granted as U.S. Pat. No. 9,442,448 on Sep. 13, 2016, which claims the benefit of and priority to JP Patent Application Nos. 2014-217046, filed Oct. 24, 2014, and 2015-065903, filed Mar. 27, 2015, the entire disclosures of which are expressly incorporated by reference herein.