Patent Publication Number: US-11396438-B2

Title: Medium transport device and medium processing apparatus

Description:
The present application is based on, and claims priority from JP Application Serial Number 2018-225108, filed Nov. 30, 2018, the disclosure of which is hereby incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a medium transport device for transporting a medium, and a medium processing apparatus including the medium transport device. 
     2. Related Art 
     Among medium processing apparatuses that perform predetermined processing on a medium, there is one configured to be capable of forming a booklet by performing saddle-stitching processing in which the center of a plurality of sheets of stacked media in the width direction is bound and then performing folding processing in which the media is folded at a binding position. 
     Such a medium processing apparatus may be incorporated into a recording system which can execute continuously from recording on the medium by a recording device represented by an ink jet printer to the saddle-stitching processing and folding processing of the recorded medium. 
     Among the medium processing apparatuses, there is one configured to transport the medium before processing to a stack portion by a medium transport device and to perform the saddle-stitching processing after allowing an end portion of the medium mounted on the stack portion to be abutted against the alignment portion and to be aligned. 
     As an example, JP-A-2010-001149 discloses a medium processing apparatus including a stack portion, an alignment portion that aligns an end portion of the medium mounted on the stack portion, a paddle that rotates while being in contact with the medium and moves the medium toward the alignment portion. In JP-A-2010-001149, the stack portion is a compile tray  441 , the alignment portion is an end guide  443 , and the paddle is a paddle  52 . 
     In the medium processing apparatus described in JP-A-2010-001149, the paddle assists abutment of the end portion of the medium against the alignment portion, and thus the medium can be reliably aligned. 
     However, depending on a type or state of the medium, for example, the medium moved by rotation of the paddle vigorously hits the alignment portion and is bounced off the alignment portion, or conversely, the medium does not reach the alignment portion, which may result in inappropriate alignment. 
     SUMMARY 
     According to an aspect of the present disclosure, there is provided a medium transport device including a feeding unit that transports a medium, a stack portion that receives the medium transported by the feeding unit between a support surface for supporting the medium in an inclined posture in which a downstream side in a transport direction is directed downward and an opposing surface opposing the support surface and stacks the medium, an alignment portion that aligns a downstream end of the medium stacked in the stack portion, a paddle that is provided between the feeding unit and the alignment portion in the transport direction and moves the medium toward the alignment portion by rotating while being in contact with the medium, and a control unit that controls an operation of the paddle, in which the control unit controls the operation of the paddle according to a condition. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of a recording system. 
         FIG. 2  is a schematic perspective view of a medium transport device. 
         FIG. 3  is a cross-sectional view taken along the III-III arrow in  FIG. 2 . 
         FIG. 4  is a diagram for explaining a flow of medium transport in the medium transport device. 
         FIG. 5  is another diagram for explaining the flow of medium transport in the medium transport device. 
         FIG. 6  is another diagram for explaining the flow of medium transport in the medium transport device. 
         FIG. 7  is another diagram for explaining the flow of medium transport in the medium transport device. 
         FIG. 8  is a flowchart illustrating a flow when controlling an operation of a paddle using a basis weight of the medium as a condition. 
         FIG. 9  is a flowchart illustrating a flow when controlling the operation of the paddle using stack height in a stack portion as the condition. 
         FIG. 10  is a flowchart illustrating a flow when controlling the operation of the paddle using the type of medium and the number of stacked media in the stack portion as the condition. 
         FIG. 11  is a flowchart illustrating a flow when controlling the operation of the paddle using a discharge amount of ink to the medium and the number of stacked media in the stack portion as the condition. 
         FIG. 12  is a graph illustrating classifications according to a relationship between temperature and humidity in an installation environment of an apparatus. 
         FIG. 13  is a flowchart illustrating a flow when controlling the operation of the paddle using the temperature and humidity in the installation environment of the apparatus, the type of medium, the discharge amount of ink to the medium, and the number of stacked media in the stack portion as the condition. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Hereinafter, the present disclosure will be schematically described. 
     According to a first aspect of the present disclosure, there is provided a medium transport device including a feeding unit that transports a medium, a stack portion that receives the medium transported by the feeding unit between a support surface for supporting the medium in an inclined posture in which a downstream side in a transport direction is directed downward and an opposing surface opposing the support surface and stacks the medium, an alignment portion that aligns a downstream end of the medium stacked in the stack portion, a paddle that is provided between the feeding unit and the alignment portion in the transport direction and moves the medium toward the alignment portion by rotating while being in contact with the medium, and a control unit that controls an operation of the paddle, in which the control unit controls the operation of the paddle according to a condition. 
     According to the first aspect, the downstream end can be aligned by allowing the medium to be appropriately abutted against the alignment portion according to the condition. 
     A second aspect of the present disclosure provides the medium transport device according to the first aspect, in which, as the condition, any of a type of the medium to be stacked, the number of stacked media previously stacked in the stack portion, a stack height of the media previously stacked in the stack portion, and a discharge amount of liquid to the medium when the medium transported by the feeding unit is a recorded medium to which the liquid is discharged for recording may be used. 
     According to the second aspect, the operation of the paddle can be controlled using, as the condition, any of the type of the medium to be stacked, the number of stacked media previously stacked in the stack portion, the stack height of the medium previously stacked in the stack portion, and the discharge amount of liquid to the medium when the medium transported by the feeding unit is the recorded medium to which the liquid is discharged for recording, and the downstream end can be aligned by allowing the downstream end to be appropriately abutted against the alignment portion. 
     A third aspect of the present disclosure provides the medium transport device according to the first aspect, in which the control unit may control the operation of the paddle according to a basis weight of the medium. 
     A fourth aspect of the present disclosure provides the medium transport device according to the first aspect, in which the control unit may use a plurality of conditions as the condition. 
     According to the fourth aspect, since the control unit uses the plurality of conditions as the condition, the control unit can control the operation of the paddle more appropriately to align the downstream end by allowing the downstream end to be abutted against the alignment portion. 
     A fifth aspect of the present disclosure provides the medium transport device according to the fourth aspect, in which the plurality of conditions may include two or more of a type of the medium to be stacked, a temperature in an installation environment of the device, a humidity in the installation environment, the number of stacked media previously stacked in the stack portion, and the discharge amount of liquid to the medium when the medium transported by the feeding unit is a recorded medium to which the liquid is discharged for recording. 
     According to the fifth aspect, the operation of the paddle can be controlled more appropriately based on two or more of the plurality of conditions to align the downstream end by allowing the downstream end to be abutted against the alignment portion. 
     A sixth aspect of the present disclosure provides the medium transport device according to any of the first to fifth aspects, in which the control unit may change a rotation speed of the paddle according to the condition. 
     According to the sixth aspect, since the control unit changes the rotation speed of the paddle according to the condition, the medium can be more appropriately abutted against the alignment portion. 
     A seventh aspect of the present disclosure provides the medium transport device according to any of the first to sixth aspects, in which the control unit may switch between driving and stopping of the paddle according to the condition. 
     According to the seventh aspect, since the control unit switches driving and stopping of the paddle according to the condition, the medium can be more appropriately abutted against the alignment portion. 
     An eighth aspect of the present disclosure provides the medium transport device according to the second aspect, in which the control unit may change a rotation start timing of the paddle according to the condition. 
     A ninth aspect of the present disclosure provides the medium transport device according to the fifth aspect, in which the control unit may use the type of the medium and the number of stacked media previously stacked in the stack portion as the plurality of conditions, stop the paddle in stacking the medium when the number of stacked media is less than a predetermined threshold value according to the type of the medium, and drive the paddle in stacking the medium when the number of stacked media is equal to or greater than the predetermined threshold value according to the type of the medium. 
     Since the stack portion stacks the medium in the inclined posture in which the downstream side in the transport direction is directed downward, when the number of stacked media previously stacked in the stack portion is small, the medium is easy to move toward the alignment portion by its own weight. For that reason, when the paddle is rotated in a state where the number of stacked media is small, there is a possibility that the medium vigorously hits the alignment portion and is bounced off the alignment portion or the medium is not appropriately aligned. 
     When the number of stacked media increases and a space between the top medium and the opposing surface narrows, frictional resistance between the top medium and a subsequent medium to be sent next to the stack portion is likely to occur, and the subsequent medium is difficult to move toward the alignment portion by its own weight. 
     The number of stacked media that makes it difficult for the medium to move toward the alignment portion by its own weight changes depending on the type of the medium. 
     According to the ninth aspect, the control unit uses the type of the medium and the number of stacked media in the stack portion as the plurality of conditions, stops the paddle in stacking the medium when the number of stacked media is less than the predetermined threshold value according to the type of the medium, and thus the possibility that the medium vigorously hits the alignment portion can be reduced when the number of stacked media in the stack portion is small. The control unit drives the paddle in stacking the medium when the number of stacked media is equal to or greater than the predetermined threshold value according to the type of the medium, and thus the medium can be more reliably aligned by allowing the medium to be abutted against the alignment portion when the number of stacked media increases. 
     A tenth aspect of the present disclosure provides the medium transport device according to the fifth aspect, in which the control unit may use the discharge amount of the liquid to the medium and the number of stacked media in the stack portion as the plurality of conditions, stop the paddle in stacking the medium when the number of stacked media is less than a predetermined threshold value according to the discharge amount of the liquid to the medium, and drives the paddle in stacking the medium when the number of stacked media is equal to or greater than the predetermined threshold value according to the discharge amount of the liquid to the medium. 
     As described above, when the paddle is rotated in the state where the number of stacked media is small, there is a possibility that the medium vigorously hits the alignment portion and is bounced off the alignment portion or the media is not appropriately aligned. When the number of stacked media increases and a space between the top medium and the opposing surface narrows, frictional resistance between the top medium and a subsequent medium to be sent next to the stack portion is likely to occur, and the subsequent medium is difficult to move toward the alignment portion by its own weight. 
     Since the frictional resistance between the media changes according to the discharge amount of the liquid to the media, the number of stacked media that makes it difficult for the medium to move toward the alignment portion by its own weight changes according to the discharge amount of the liquid to the medium. 
     According to the tenth aspect, the control unit uses the discharge amount of the liquid to the medium and the number of stacked media in the stack portion as the plurality of conditions, stops the paddle in stacking the medium when the number of stacked media is less than the predetermined threshold value according to the discharge amount of the liquid to the medium, and thus the possibility that the medium vigorously hits the alignment portion and is bounced off the alignment portion can be reduced when the number of stacked media in the stack portion is small. The control unit drives the paddle in stacking the medium when the number of stacked media is equal to or greater than the predetermined threshold value according to the discharge amount of the liquid to the medium, and thus the medium can be more reliably aligned by allowing the medium to be abutted against the alignment portion when the number of stacked media increases. 
     An eleventh aspect of the present disclosure provides the medium transport device according to the tenth aspect, in which the threshold value of the number of stacked media may be set to be lower as the discharge amount of the liquid to the medium increases. 
     Since the frictional resistance between the media increases as the discharge amount of the liquid to the medium increases, even if the number of stacked media in the stack portion is small, the medium is difficult to move toward the alignment portion by its own weight. 
     According to the eleventh aspect, since the threshold value of the number of stacked media in the stack portion is set lower as the discharge amount of the liquid to the medium increases, a possibility of an abutment failure of the medium against the alignment portion can be avoided more reliably. 
     A twelfth aspect of the present disclosure provides the medium transport device according to the tenth aspect, in which the control unit may make a rotation speed of the paddle when the discharge amount of the liquid to the medium is a first discharge amount faster than the rotation speed when the discharge amount of the liquid to the medium is a second discharge amount smaller than the first discharge amount. 
     As the discharge amount of the liquid to the medium increases, the frictional resistance between the medium increases. According to the twelfth aspect, since the control unit makes the rotation speed of the paddle when the discharge amount of the liquid to the medium is the first discharge amount faster than the rotation speed when the discharge amount of the liquid to the medium is the second discharge amount smaller than the first discharge amount, movement of the medium by the paddle can be reliably performed when the discharge amount of the liquid to the medium is large and the frictional resistance between the media is large. 
     A thirteenth aspect of the present disclosure provides the medium transport device according to the tenth aspect, in which the control unit may set the threshold value according to a difference between the discharge amount of the liquid to a first surface of the medium and the discharge amount of the liquid to a second surface opposite to the first surface. 
     A fourteenth aspect of the present disclosure provides the medium transport device according to any one of the first to the thirteenth aspect, in which the control unit may drive the paddle after an upstream end of the stacked medium passes a position where the stacked medium receives a feeding force from the feeding unit. 
     According to the fourteenth aspect, since the control unit drives the paddle after the upstream end of the stacked medium passes the position where the medium to be stacked receives the feeding force from the feeding unit, the possibility of the medium being buckled between the feed roller pair and the paddle can be reduced. 
     A fifteenth aspect of the present disclosure provides the medium transport device according to any one of the first to thirteenth aspect, in which the feeding unit is a feed roller pair including a driving roller controlled to rotate by the control unit and a driven roller driven to rotate following the rotation of the driving roller, and the control unit makes a circumferential speed of the paddle faster than a circumferential speed of the driving roller. 
     According to the fifteenth aspect, since the control unit makes the circumferential speed of the paddle faster than the circumferential speed of the driving roller, the possibility of the medium being buckled between the feed roller pair and the paddle can be reduced. 
     A sixteenth aspect of the present disclosure provides the medium transport device according to any one of the first to fifteenth aspect, in which the paddle includes a first paddle provided on a rotation shaft intersecting the transport direction and second paddles provided on the rotation shaft and disposed on both sides of the first paddle, and the first paddle and the second paddles are disposed such that phases in a circumferential direction of a rotation shaft are different from each other. 
     According to a seventeenth aspect of the present disclosure, there is provided a medium processing apparatus including the medium transport device according to the first to sixteenth aspects and a processing unit that performs processing on the medium stacked in the stack portion. 
     According to the seventeenth aspect, the same function and effect as any of the first to sixteenth aspects can be obtained in the medium processing apparatus including the medium transport device according to the first to sixteenth aspects and the processing unit that performs processing on the medium stacked in the stack portion. 
     An eighteenth aspect of the present disclosure provides the medium processing apparatus according to the seventeenth aspect, in which the processing unit may include a binding unit that binds the medium and a folding unit that folds the medium at a binding position by the binding unit. 
     According to the eighteenth aspect, the same function and effect as the seventeenth aspect can be obtained in the medium processing apparatus in which the processing unit includes the binding unit that binds the medium and the folding unit that folds the medium at the binding position by the binding unit. 
     First Embodiment 
     Hereinafter, a first embodiment will be described with reference to the drawings. In the XYZ coordinate system illustrated in each drawing, the X-axis direction indicates an apparatus depth direction, the Y-axis direction indicates an apparatus width direction, and the Z-axis direction indicates an apparatus height direction. 
     Overview of Recording System 
     As an example, a recording system  1  illustrated in  FIG. 1  includes a recording unit  2 , an intermediate unit  3 , a first unit  5 , and a second unit  6  in order from the right to the left in  FIG. 1 . In this embodiment, the second unit  6  is a “medium processing apparatus” that performs saddle-stitching processing on a medium. 
     The recording unit  2  performs recording on the transported medium. The intermediate unit  3  receives a recorded medium from the recording unit  2  and delivers the medium to the first unit  5 . The first unit  5  performs end-stitching processing to bundle received media and bind ends of the media, or passes the received medium as it is and delivers the received medium to the second unit  6 . The second unit  6  includes a medium transport device  70  for transporting a medium, and performs saddle-stitching processing in which the center of the medium is bound and folded to form a booklet. 
     Hereinafter, description will be made in detail in order of the recording unit  2 , the intermediate unit  3 , the first unit  5 , and the second unit  6  (medium processing apparatus). 
     About Recording Unit 
     The recording unit  2  will be described with reference to  FIG. 1 . The recording unit  2  is configured as a multifunction machine including a printer unit  10  having a line head  20  as a recording unit that performs recording on a medium, and a scanner unit  11 . In this embodiment, the line head  20  is configured as a so-called ink jet recording head that performs recording by discharging ink, which is liquid, onto the medium. 
     Below the printer unit  10 , a cassette storage unit  14  including a plurality of medium accommodation cassettes  12  is provided. The medium P accommodated in the medium accommodation cassette  12  is fed to a recording area by the line head  20  through a feeding path  21  indicated by a solid line in  FIG. 1  and a recording operation is performed. The medium after being recording by the line head  20  is sent to a first discharge path  22  for discharging the medium to a discharge tray  13  for a recorded medium provided above the line head  20  or a second discharge path  23  for sending the medium to the intermediate unit  3 . 
     In  FIG. 1 , the first discharge path  22  is indicated by a broken line, and the second discharge path  23  is indicated by a one-dot chain line. The second discharge path  23  extends in the +Y direction of the recording unit  2  and delivers the medium to a receiving path  30  of the adjacent intermediate unit  3 . 
     The recording unit  2  is provided with a reversing path  24  indicated by a two-dot chain line in  FIG. 1 , and is configured to be capable of double-sided recording in which recording is performed on the second side of the medium by reversing the recorded medium on the first side of the medium. In each of the feeding path  21 , the first discharge path  22 , the second discharge path  23 , and the reversing path  24 , one or more pairs of transport rollers (not illustrated) are disposed as an example of a unit for transporting the medium. 
     The recording unit  2  is provided with a first control unit  25  that controls an operation related to transport and recording of the medium in the recording unit  2 . The recording system  1  is configured such that the recording unit  2 , the intermediate unit  3 , the first unit  5 , and the second unit  6  are mechanically and electrically connected to each other and the medium can be transported from the recording unit  2  to the second unit  6 . The first control unit  25  can control various operations in the intermediate unit  3 , the first unit  5 , and the second unit  6  connected to the recording unit  2 . 
     The recording system  1  is configured to be able to input settings in the recording unit  2 , the intermediate unit  3 , the first unit  5 , and the second unit  6  from an operation panel (not illustrated). The operation panel can be provided in the recording unit  2  as an example. 
     About Intermediate Unit 
     The intermediate unit  3  will be described with reference to  FIG. 1 . The intermediate unit  3  illustrated in  FIG. 1  delivers the medium received from the recording unit  2  to the first unit  5 . The intermediate unit  3  is disposed between the recording unit  2  and the first unit  5 . The medium transported through the second discharge path  23  of the recording unit  2  is received by the intermediate unit  3  from the receiving path  30  and transported toward the first unit  5 . The receiving path  30  is indicated by a solid line in  FIG. 1 . 
     In the intermediate unit  3 , there are two transport paths for transporting the medium. The first transport path is a path through which the medium is transported from the receiving path  30  to a joining path  33  through a first switchback path  31  indicated by a dotted line in  FIG. 1 . The second path is a path through which the medium is transported from the receiving path  30  to the joining path  33  through a second switchback path  32  indicated by a two-dot chain line in  FIG. 1 . 
     The first switchback path  31  is a path for switching back the medium in the arrow A 2  direction after receiving the medium in the arrow A 1  direction. The second switchback path  32  is a path for switching back the medium in the arrow B 2  direction after receiving the medium in the arrow B 1  direction. 
     The receiving path  30  branches into the first switchback path  31  and the second switchback path  32  at a branch portion  35 . The branch portion  35  is provided with a flap (not illustrated) that switches a destination of the medium to either the first switchback path  31  or the second switchback path  32 . 
     The first switchback path  31  and the second switchback path  32  join at a joining portion  36 . Accordingly, even if the medium is sent from the receiving path  30  to either the first switchback path  31  or the second switchback path  32 , the medium can be delivered to the first unit  5  through the common joining path  33 . 
     The medium transported on the joining path  33  is delivered to the first transport path  47  of the first unit  5  from the +Y direction of the intermediate unit  3 . 
     One or more pairs of the transport rollers (not illustrated) are disposed in each of the receiving path  30 , the first switchback path  31 , the second switchback path  32 , and the joining path  33 . 
     When recording is continuously performed on a plurality of media in the recording unit  2 , the medium that has entered the intermediate unit  3  is alternately sent to the transport path passing through the first switchback path  31  and the transport path passing through the second switchback path  32 . This can increase the throughput of medium transport in the intermediate unit  3 . 
     In a case a configuration in which recording is performed by discharging ink (liquid) to the medium as in the line head  20  of this embodiment, if the medium is wet when processing is performed by the first unit  5  or the second unit  6  in a subsequent stage, a recording surface may be rubbed or consistency of the medium may be poor. 
     By delivering the recorded medium from the recording unit  2  to the first unit  5  through the intermediate unit  3 , the transport time until the recorded medium is sent to the first unit  5  can be made long, and the medium can be further dried before reaching the first unit  5  or the second unit  6 . 
     About First Unit 
     The first unit  5  will be described with reference to  FIG. 1 . The first unit  5  has a first transport path  47  connected to a first processing unit  42  that performs end-stitching processing, and a second transport path  51  that sends the received medium to the second unit  6  without passing through the first processing unit  42 . The end-binding processing is, for example, processing for binding one corner of the medium or one side of the medium. The second transport path  51  branches from the first transport path  47  at the first branch portion  56 . 
     The first unit  5  includes a first tray  44  that receives the medium after end-stitching processing discharged from the first unit  5 . The first tray  44  is provided so as to protrude from the first unit  5  in the +Y direction. In this embodiment, the first tray  44  includes a base portion  44   a  and an extension portion  44   b,  and the extension portion  44   b  is configured to be storable in the base portion  44   a.    
     In this embodiment, the first processing unit  42  is a stapler that performs end-binding processing in which a plurality of media are superposed and the end portion is bound. The first processing unit  42  may be configured to perform punching processing or the like for forming a hole at a predetermined position of the medium. 
     The medium received by the first unit  5  is transported on the first transport path  47  illustrated by the solid line in  FIG. 1 . The medium P transported on the first transport path  47  is sent to the processing tray  48 , and is stacked on the processing tray  48  with the rear end in the transport direction aligned. When a predetermined number of media P are stacked on the processing tray  48 , the first processing unit  42  performs end-stitching processing on the rear end of the medium P. The medium after end-stitching processing is discharged to the first tray  44  by a discharging unit (not illustrated). 
     To the first transport path  47 , a third transport path  53  branched from the first transport path  47  at the second branch portion  57  downstream of the first branch portion  56  is connected. The third transport path  53  is a path for discharging the medium to an upper tray  49  provided above the first unit  5 . In the upper tray  49 , the medium not subjected to processing can be stacked. 
     In each of the first transport path  47 , the second transport path  51 , and the third transport path  53 , one or more pairs of transport rollers (not illustrated) are disposed as an example of a unit for transporting the medium. Each of the first branch portion  56  and the second branch portion  57  is provided with a flap (not illustrated) for switching the destination of the medium. 
     About Second Unit 
     Subsequently, the second unit  6  will be described. The second unit  6  illustrated in  FIG. 1  includes the medium transport device  70 . The medium delivered from the second transport path  51  of the first unit  5  is transported on the transport path  60  illustrated by the solid line in  FIG. 1  and is sent to a second processing unit  62 . 
     In the second processing unit  62 , after the medium is bound, the saddle-stitching processing can be performed to fold the medium at the binding position into a booklet. The saddle-stitching processing by the medium transport device  70  and the second processing unit  62  will be described in detail later. 
     A bundle of media after the saddle-stitching processing is discharged to a second tray  65  illustrated in  FIG. 1 . The second tray  65  includes a restriction portion  66  at the tip in the +Y direction, which is a medium discharge direction, and suppresses that the bundle of media discharged to the second tray  65  protrudes from the second tray  65  or falls from the second tray  65  in the medium discharge direction. Reference numeral  67  denotes a guide portion  67  for guiding the bundle of media M discharged from the second unit  6  to the second tray  65 . 
     About Medium Transport Device 
     The medium transport device  70  will be described with reference to  FIGS. 1 to 3 . The medium transport device  70  illustrated in  FIG. 2  includes a feed roller pair  75  as a feeding unit for transporting the medium P, a stack portion  71  for stacking the medium P, and the alignment portion  76  for aligning a downstream end E 1  ( FIG. 3 ) of the medium P stacked in the stack portion  71 , a paddle  81 , and a control unit  80  ( FIG. 1 ). The feed roller pair  75  includes a driving roller  75   a  and a driven roller  75   b  that is driven to rotate by rotation of the driving roller  75   a,  and the driving roller  75   a  is controlled by the control unit  80  to rotate. 
     In  FIG. 2 , the stack portion  71  receives and stacks the medium P transported by the feed roller pair  75  between a support surface  85  for supporting the medium in an inclined posture in which a downstream side in a transport direction +R is directed downward and an opposing surface  86  opposing the support surface  85 . The paddle  81  is provided between the feed roller pair  75  and an alignment portion  76  in the transport direction +R, and moves the medium P toward the alignment portion  76  by rotating while being in contact with the medium P. The control unit  80  ( FIG. 1 ) controls the operation of the medium transport device  70  including the paddle  81  and the driving roller  75   a.    
     As illustrated in  FIG. 3 , the second processing unit  62 , which is a processing unit that performs processing on the medium P stacked in the stack portion  71  of the second unit  6  (medium processing apparatus), includes a binding unit  72  for binding the bundle of media M consisting of a plurality of media P stacked in the stack portion  71  at a binding position, and a folding roller pair  73  as a folding unit for folding the bundle of media M at the binding position. 
     In  FIG. 3 , the reference numeral G indicates a joining position G where the transport path  60  and the stack portion  71  join. The binding position in this embodiment is the central portion C in the transport direction +R of the medium P stacked in the stack portion  71 . The medium P is sent from the transport path  60  to the stack portion  71  by the feed roller pair  75 . 
     In the stack portion  71 , the alignment portion  76  capable of abutting on the downstream end E 1  of the transport direction +R of the medium P stacked in the stack portion  71 , and an abutment portion  77  capable of abutting on an upstream end E 2  of the transport direction +R of the medium P stacked in the stack portion  71  are provided. 
     The alignment portion  76  and the abutment portion  77  are configured to be movable in both the transport direction +R of the medium P in the stack portion  71  and a reverse direction −R thereof illustrated in  FIG. 3 . The alignment portion  76  and the abutment portion  77  can be moved in the transport direction +R and the reverse direction −R, for example, using a rack and pinion mechanism, a belt moving mechanism, or the like operated by the power of a drive source (not illustrated). The alignment portion  76  is configured to be movable also in the S-axis direction which intersects the transport direction +R in  FIG. 3 . The movement of the alignment portion  76  will be described in detail when a stack operation in the stack portion  71  is described. 
     The alignment portion  76  includes an eaves portion  76   a  facing a downstream end region K close to the downstream end E 1  of the medium P stacked in the stack portion  71 . 
     A binding unit  72  for binding the bundle of media M stacked in the stack portion  71  at a predetermined position in the transport direction +R is provided downstream of the joining position G. The binding unit  72  is a stapler as an example. In this embodiment, as illustrated in  FIG. 2 , a plurality of binding units  72  are provided at intervals in the X-axis direction which is the width direction of the medium. 
     As described above, the binding unit  72  is configured to bind the bundle of media M with the central portion C of the bundle of media M as the binding position in the transport direction +R. 
     A folding roller pair  73  is provided downstream of the binding unit  72 . The opposing surface  86  is open at a position corresponding to a nip position N of the folding roller pair  73 , and an approach path  78  of the bundle of media M from the stack portion  71  to the folding roller pair  73  is formed. At the entrance of the approach path  78  of the opposing surface  86 , slopes are formed which guide the central portion C, which is the binding position, from the stack portion  71  to the nip position N. 
     A blade  74 , which is capable of switching between a retreated state retreated from the stack portion  71  as illustrated in  FIG. 3  and an advanced state advanced to the binding position of the bundle of media M stacked in the stack portion  71  as illustrated in the left diagram of  FIG. 7 , is provided on the opposite side of the folding roller pair  73  with the stack portion  71  interposed therebetween. Reference numeral  79  denotes a hole  79  provided in the support surface  85 , and the blade  74  can pass through the hole  79 . 
     About medium transport during saddle-stitching processing Next, with reference to  FIGS. 4 to 7 , a basic flow from transporting the medium P to saddle stitching and discharging the medium P in the medium transport device  70  will be described. 
     First, as illustrated in the left diagram of  FIG. 4 , the medium P is transported from the transport path  60  toward the stack portion  71 . The medium P is transported from the transport path  60  to the stack portion  71  by the feed roller pair  75 . While the medium P is being sent to the stack portion  71  by the feed roller pair  75 , the paddle  81  retreats from the stack portion  71 . 
     As illustrated in the right diagram of  FIG. 4 , when the upstream end E 2  of the medium P comes out of the nip of the feed roller pair  75 , the medium P moves toward the alignment portion  76  by its own weight and the paddle  81  provided upstream of the alignment portion  76  is rotated to abut the medium P toward the alignment portion  76 . 
     The operation of the paddle  81  is controlled by the control unit  80  according to the conditions as described later. The control of the paddle  81  by the control unit  80  will be described in detail after the flow of transport of the medium P in the medium transport device  70  is generally described. 
     In the left diagram of  FIG. 4 , the alignment portion  76  is disposed such that the distance from the joining position G of the transport path  60  and the stack portion  71  to the alignment portion  76  is longer than the length of the medium P. With this configuration, as illustrated in the right diagram of  FIG. 4 , the medium P is received by the stack portion  71  without the upstream end E 2  of the medium P transported from the transport path  60  remaining in the transport path  60 . The position of the alignment portion  76  in the transport direction +R of the stack portion  71  can be changed according to a size of the medium P. 
     When the paddle  81  is rotated by a predetermined number of rotations so that the medium P abuts against the alignment portion  76 , the paddle  81  is stopped in a state of being retreated from the stack portion  71 . The alignment portion  76  is displaced in the −S direction as illustrated in the left diagram of  FIG. 5  and the eaves portion  76   a  presses the medium P toward the support surface  85 , and then, the alignment portion  76  is displaced in the +S direction to return to the original position, and prepares to receive the next medium P. 
     The operations from the left diagram of  FIG. 4  to the left diagram of  FIG. 5  are repeated, and a plurality of media P are stacked in the stack portion  71  in a state where the downstream end E 1  is aligned with the alignment portion  76 . The right diagram of  FIG. 5  illustrates a state in which the plurality of media P are stacked in the stack portion  71 . A bundle of media P is referred to as a bundle of media M. 
     When a predetermined number of media P are stacked in the stack portion  71 , the binding unit  72  performs binding processing in which the central portion C in the transport direction +R of the bundle of media M is bound. At the time when transport of the medium P from the conveyance path  60  to the stack portion  71  is completed, since the central portion C is shifted from the position of the binding unit  72  as illustrated in the right diagram of  FIG. 5 , the alignment portion  76  is moved in the −R direction and the central portion C of the bundle of media M is disposed at a position opposing the binding unit  72 , as illustrated in the left diagram of  FIG. 6 . Furthermore, the abutment portion  77  is moved in the +R direction to abut on the upstream end E 2  of the bundle of media M. The downstream end E 1  and the upstream end E 2  of the bundle of media M are aligned by the alignment portion  76  and the abutment portion  77 , and the center portion C of the bundle of media M is bound by the binding unit  72 . 
     When the bundle of media M is bound by the binding unit  72 , the alignment portion  76  is moved in the +R direction as illustrated in the right diagram of  FIG. 6 , and the bundle of media M is moved such that the bound central portion C is disposed at a position opposing the nip position N of the folding roller pair  73 . The bundle of media M can be moved in the +R direction by moving only the alignment portion  76  in the +R direction while maintaining a state in which the bundle of media M abuts on the alignment portion  76  by its own weight. The abutment portion  77  may be moved in the +R direction so as to maintain the state of being abutted on the upstream end E 2  of the bundle of media M. 
     Subsequently, when the central portion C of the bundle of media M is disposed at a position opposing the nip position N of the folding roller pair  73 , the blade  74  is advanced in the +S direction to bend the central portion C toward the folding roller pair  73  as illustrated in the left diagram of  FIG. 7 . The central portion C of the bent bundle of media M is moved toward the nip position N of the folding roller pair  73  through the approach path  78 . 
     As illustrated in the right diagram of  FIG. 7 , when the central portion C of the bundle of media M is nipped by the folding roller pair  73 , the folding roller pair  73  is rotated, and the bundle of media M is discharged toward the second tray  65  ( FIG. 1 ) while being folded at the central portion C by the nip pressure of the folding roller pair  73 . 
     After the central portion C is nipped by the folding roller pair  73 , the alignment portion  76  moves in the +R direction, and returns to the state of the left diagram of  FIG. 4  to prepare for the reception of the next medium P in the stack portion  71 . 
     The transport path  60  can be provided with a crease forming mechanism that creases the central portion C of the medium P. By making a crease in the central portion C which is the folding position set by the folding roller pair  73 , the bundle of media M can be easily folded at the central portion C. 
     About Control of Operation of Paddle by Control Unit 
     Subsequently, control of the operation of paddle  81  by the control unit  80  will be described. 
     The control unit  80  controls the operation of the paddle  81  according to the condition. In this embodiment, as the conditions to be used by the control unit  80 , conditions relating to the medium P at the time of stacking the medium P, for example, the number of stacked media P previously stacked in the stack portion  71 , a discharge amount of ink discharged to the medium P at the time of recording in the recording unit  2 , whether recording on the medium P is double-sided recording or single-sided recording, and environmental conditions such as temperature and humidity when stacking the medium P are included, in addition to the type, rigidity, thickness, basis weight, and the like of the medium P. 
     When the paddle  81  is rotated under uniform conditions, the medium P moved by the rotation of the paddle  81  may hit the alignment portion  76  and is bounced off the alignment portion, or conversely, may not reach the alignment portion  76  depending on the conditions, which may result in inappropriate alignment. 
     In this embodiment, the downstream end E 1  of the medium P can be appropriately abutted against the alignment portion  76  and the downstream end E 1  can be aligned, by controlling the operation of the paddle  81  according to the condition by the control unit  80 . 
     In this embodiment, although the configuration in which the paddle  81  is controlled by the control unit  80  is adopted, for example, when a configuration in which the entire recording system  1  can be controlled by the first control unit  25  provided in the recording unit  2  is adopted, the paddle  81  can be controlled by the first control unit  25 . 
     The control unit  80  can change, for example, the rotation speed of the paddle  81  according to the condition. By changing the rotation speed of the paddle  81 , the medium P can be moved toward the alignment portion  76  at a more appropriate speed. 
     The control unit  80  can switch driving and stopping of the paddle  81  according to the condition. By controlling the paddle  81  in this manner, the paddle  81  can be driven under the condition that assistance with paddle  81  is required, and the paddle  81  can be stopped under the condition that assistance with paddle  81  is not required, in aligning the medium P by allowing the medium P to be abutted against the alignment portion  76 . Thus, the medium P can be more appropriately abutted against the alignment portion  76 . 
     Hereinafter, control of the operation of the paddle  81  will be described by taking a specific example of the condition. 
     Control According to One Condition 
     As the conditions to be used by the control unit  80 , any of the type of medium P to be stacked, the number of stacked media previously stacked in the stack portion  71 , the stack height of the medium P previously stacked in the stack portion  71 , and the discharge amount of ink (liquid) to the medium P transported by the feed roller pair can be used. In this embodiment, the medium P transported by the medium transport device  70  is a recorded medium to which ink is discharged for recording in the recording unit  2 , and the discharge amount of ink is an amount of ink discharged to the medium P by the line head  20 . 
     For example, with reference to a flowchart illustrated in  FIG. 8 , a case where the difference in basis weight of the stacked media P is used as the condition will be described. 
     The control unit  80  uses the basis weight of the medium P as the condition, and determines whether or not the basis weight of the medium P is equal to or greater than a predetermined weight (step S 1 ). When the determination result in step S 1  is YES, that is, when it is determined that the basis weight of the medium P is equal to or greater than the predetermined weight, the rotation speed of the paddle  81  is set to a first speed (step S 2 ). When the determination result in step S 1  is NO, that is, when it is determined that the basis weight of the medium P is less than the predetermined value, the rotation speed of the paddle  81  is set to a second speed slower than the first speed (step S 3 ). 
     Since the medium having a large basis weight is heavy and difficult to move by the external force, when it is determined that the basis weight of the medium P is equal to or greater than the predetermined weight, the paddle  81  can be reliably moved in the +R direction to abut against the alignment portion  76  by setting the rotation speed of the paddle  81  to the first speed. On the other hand, when it is determined that the basis weight of the medium P is less than the predetermined weight (NO in step S 1 ), since the rotation speed of the paddle  81  is set to the second speed slower than the first speed, the possibility that the light medium having a small basis weight vigorously hit the alignment portion  76  and is bounced off the alignment portion  76  can be reduced. 
     When the rotation speed of the paddle  81  is set to the second speed, the second speed may also be set to be zero, that is, the paddle  81  may also be in a state of being stopped. 
     Next, with reference to the flowchart illustrated in  FIG. 9 , a case where the stack height of the medium P stacked in the stack portion  71  is used as the condition will be described. 
     The control unit  80  uses the stack height of the media P previously stacked in the stack portion  71  as the condition, and determines whether the stack height is equal to or greater than a predetermined height (step S 11 ). When the determination result in step S 11  is YES, that is, when it is determined that the stack height is equal to or greater than the predetermined height, the paddle  81  is driven (step S 12 ). When the determination result in step S 11  is NO, that is, when it is determined that the stack height is less than the predetermined height, the paddle  81  is stopped (step S 13 ). 
     In a state in which the stack height of the medium P previously stacked in the stack portion  71  is low, that is, in the state where the space between the top medium P 1  and the opposing surface  86  in the bundle of media M stacked in the stack portion  71  in  FIG. 3  is wide, the subsequent medium to be sent next to the stack portion is easy to move downstream by its own weight. For that reason, when the paddle  81  is driven to assist the downstream movement of the medium P, there is a possibility that the medium P vigorously hit the alignment portion  76  and is bounced off the alignment portion  76  and the medium is not appropriately aligned. 
     On the other hand, when the stack height increases and the space between the top medium P 1  and the opposing surface  86  narrows, there is a possibility that frictional resistance between the top medium P 1  and the subsequent medium sent next to the stack portion  71  is likely to occur, and the subsequent medium is difficult to move toward the alignment portion  76 , and the downstream end E 1  does not reach the alignment portion  76  only by its own weight. 
     Accordingly, the paddle  81  is driven (step S 12 ) when it is determined in step S 11  that the stack height is equal to or greater than the predetermined height and the paddle  81  is stopped (step S 13 ) when it is determined that the stack height is less than the predetermined height, thereby capable of avoiding the possibility that the medium P vigorously hits the or possibility that the downstream end E 1  does not reach the alignment portion  76 . 
     Similar to the flowchart illustrated in  FIG. 8 , the paddle  81  may be rotated at the first speed in step S 12 , and the paddle  81  may be rotated at the second speed slower than the first speed in step S 13 . 
     The number of stacked media previously stacked in the stack portion  71  corresponds to the height of the stack. Thus, a configuration in which the paddle  81  is driven when the number of stacked media in the stack portion  71  is equal to or greater than a predetermined number and the paddle  81  is stopped when the number of stacked media is smaller than the predetermined number may be adopted. 
     When the discharge amount of ink (liquid) to the medium P transported by the feed roller pair increases, the frictional resistance between the media increases, and thus the medium P is difficult to move toward the alignment portion  76  by its own weight. From this, a configuration, in which the paddle  81  is driven or rotated at the first speed when the discharge amount of ink (liquid) to the medium P is equal to or greater than a predetermined amount, or the paddle  81  is stopped or rotated at the second speed slower than the first speed when the discharge amount is less than the predetermined amount, can be adopted. 
     The paddle  81  can also be controlled according to the difference in thickness of the medium as the type of medium. 
     The medium becomes more difficult to move toward the alignment portion  76  as the thickness of the medium increases, and thus a configuration in which the paddle  81  is driven for the medium having a predetermined thickness or more can be adopted. For the medium having the predetermined thickness or more, the rotation speed of the paddle can be made faster than that of the medium having a thickness less than the predetermined thickness. 
     When the bundle of media M is subjected to saddle-stitching processing by the second processing unit  62  to form a booklet, the medium P to be finally stacked in the stack portion  71  is a cover and a back cover. For that reason, the medium P to be finally stacked in the stack portion  71  may be thicker than the other media stacked so far. In such a case, by controlling the paddle  81  according to the difference in thickness of the medium, the downstream end E 1  can be aligned by allowing the downstream end E 1  to be appropriately abutted against the alignment portion  76  even when the thickness of the stacked medium is partially different. 
     As described above, the operation of the paddle  81  can be controlled using, as the condition, any of the type of the medium to be stacked, the number of stacked media previously stacked in the stack portion  71 , the stack height of the medium previously stacked in the stack portion  71 , and the discharge amount of liquid to the medium when the medium transported by the feeding unit is the recorded medium to which the liquid is discharged for recording, and the downstream end E can be aligned by allowing the downstream end E to be appropriately abutted against the alignment portion  76 . 
     The control unit  80  can determine whether to rotate the paddle  81 , or can change not only the rotation speed when the paddle  81  is rotated but also the timing of starting the rotation. 
     Control According to Plurality of Conditions 
     The control unit  80  can be configured to control the paddle  81  using a plurality of conditions as the condition. By using the plurality of conditions, the operation of the paddle  81  can be controlled more appropriately. 
     The plurality of conditions includes two or more of the type of medium P to be stacked, temperature in an installation environment of the apparatus, humidity in the installation environment of the apparatus, the number of stacked media previously stacked in the stack portion  71 , and the discharge amount of ink to the medium P. 
     For example, the control unit  80  uses, as the plurality of conditions, the type of medium and the number of stacked media previously stacked in the stack portion  71 . 
     The control unit  80  has a threshold value T according to the type of the medium P as illustrated in Table 1 below, changes the threshold value T according to the type of the medium P, and controls the paddle  81  according to a flowchart illustrated in  FIG. 10 . 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Type of medium 
                 Threshold value T 
               
               
                   
                   
               
             
            
               
                   
                 first paper type 
                 T1 
               
               
                   
                 second paper type 
                 T2 
               
               
                   
                 third paper type 
                 T3 
               
               
                   
                 . 
                 . 
               
               
                   
                 . 
                 . 
               
               
                   
                 . 
                 . 
               
               
                   
                   
               
            
           
         
       
     
     In  FIG. 10 , in step S 21 , the control unit  80  determines whether the number of stacked media is equal to or greater than a predetermined threshold value T according to the type of medium P. For example, when the medium P to be stacked is a first paper type, it is determined whether the number of stacked media is equal to or more than the threshold value T1. 
     When the determination result in step S 21  is YES, that is, when it is determined that the number of stacked media is greater than or equal to the predetermined threshold value T according to the type of the medium P, the paddle  81  is driven in stacking the medium P (Step S 22 ). When the determination result in step S 21  is NO, that is, when it is determined that the number of stacked media is less than the predetermined threshold value T according to the type of the medium P, the paddle  81  is stopped in stacking the medium P (step S 23 ). 
     As described above, in the stack portion  71  in which the medium is stacked in the inclined posture in which the downstream side in the transport direction is directed downward, the stacked medium P is easy to move toward the alignment portion  76  by its own weight when the number of stacked media previously stacked in the stack portion is small and is difficult to move when the number of stacked media increases. 
     Here, the number of stacked media that makes it difficult for the medium P to move in the stack portion  71  by its own weight changes according to the type of the medium P. 
     In this embodiment, as illustrated in the flowchart of  FIG. 10 , the control unit  80  switches driving and stopping of the paddle  81  using the threshold value T of the number of stacked media in consideration of the type of the media P, and thus the medium P can be more reliably aligned with the alignment portion  76 . 
     The control unit  80  can use the discharge amount of ink to the medium P and the number of stacked media in the stack portion  71  as the plurality of conditions. 
     The control unit  80  has a predetermined threshold value t according to the discharge amount of ink to the medium P as illustrated in Table 2 below, changes the predetermined threshold value t according to the discharge amount of ink to the medium P, and controls the paddle  81  according to a flowchart illustrated in  FIG. 11 . 
     In the following, recording density (%) is used as a value corresponding to the discharge amount of ink to the medium P. The recording density (%) is a value that increases or decreases according to the ink discharge amount, and is a ratio of the total ink discharge amount (g) to the maximum ink ejection amount (g) to a recordable region of one sheet of paper. That is, recording density (%)=total ink discharge amount (g) to one sheet of paper/maximum ink ejection amount (g)×100. The maximum ink ejection amount (g) to the recordable region of one sheet of paper can be obtained from the maximum ink ejection amount (g) per unit area by the line head  20  provided in the recording unit  2 . 
     The present disclosure is not limited to this, and the recording density (%) can also be a ratio of an area of the region where ink is discharged to the area of one sheet of paper. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 Recording density (%) 
                   
               
               
                   
                 (discharge amount of ink to medium) 
                 Threshold value t 
               
               
                   
                   
               
             
            
               
                   
                 0 or more, less than 10 
                 t1 
               
               
                   
                 10 or more, less than 20 
                 t2 
               
               
                   
                 20 or more, less than 30 
                 t3 
               
               
                   
                 . 
                 . 
               
               
                   
                 . 
                 . 
               
               
                   
                 . 
                 . 
               
               
                   
                   
               
            
           
         
       
     
     In  FIG. 11 , in step S 31 , the control unit  80  determines whether the number of stacked media is equal to or greater than the predetermined threshold value t according to the recording density of the medium P (discharge amount of ink to the medium P). For example, when the recording density on the stacked medium P is 0% or more and less than 10%, it is determined whether or not the number of stacked media is equal to or greater than a threshold value t1. 
     When the determination result in step S 31  is YES, that is, when it is determined that the number of stacked media is greater than or equal to the predetermined threshold value t according to the recording density of the medium P, the paddle  81  is driven in stacking the medium P (Step S 32 ). When the determination result in step S 31  is NO, that is, when it is determined that the number of stacked media is less than the predetermined threshold value t according to the recording density of the medium P, the paddle  81  is stopped in stacking the medium P (step S 33 ). 
     Although the medium P stacked in the stack portion  71  is easy to move toward the alignment portion  76  by its own weight when the number of stacked media previously stacked in the stack portion is small and is difficult to move when the number of stacked media increases, the number of stacked media that makes it difficult for the medium P to move by its own weight changes according to the frictional resistance between the media. The frictional resistance between the media changes according to the discharge amount of ink to the medium P. When the discharge amount of ink to the medium P is large, that is, the recording density is high, the frictional resistance between the media tends to be large, and when the discharge amount of ink to the medium P is small, that is, the recording density is low, the frictional resistance between the media tends to be small. 
     In this embodiment, as illustrated in the flowchart of  FIG. 11 , the control unit  80  switches driving and stopping of the paddle  81  using the threshold value t of the number of stacked media in consideration of the discharge amount of ink to the medium P, and thus the medium P can be more reliably aligned with the alignment portion  76 . 
     The threshold value t of the number of stacked media according to the discharge amount of ink to the medium P is set lower as the discharge amount of ink to the medium P increases. That is, in Table 2, t1&gt;t2&gt;t3. 
     Since the frictional resistance between the media increases as the discharge amount of the ink to the medium P increases, even if the number of stacked media in the stack portion  71  is small, the medium P with the discharge amount of ink to the medium P is large is difficult to move toward the alignment portion  76  by its own weight. By setting the threshold value t to be lower as the discharge amount of ink to the medium P increases, the possibility of the abutment failure of the medium P against the alignment portion  76  can be suppressed more reliably. 
     When the medium P to be stacked is in a state of being susceptible to curling, the threshold value t of the number of stacked media according to the ink discharge amount may be set to a low value. For example, if there is a difference between the discharge amount of ink to the first surface and the opposite second surface of the medium, the medium tends to curl. Accordingly, when there is a difference between the discharge amount of ink to the first surface and the second surface of the medium, the threshold value t may be set low. 
     The control unit  80  can make the rotation speed of the paddle  81  when the discharge amount of ink to the medium P is the first discharge amount faster than the rotation speed of the paddle  81  when the discharge amount of ink to the medium P is the second discharge amount smaller than the first discharge amount. 
     As described above, as the discharge amount of ink to the medium P increases, the frictional resistance between the media increases. Accordingly, by making the rotation speed of the paddle  81  when the discharge amount of ink to the medium P is the first discharge amount faster than the rotation speed of the paddle  81  when the discharge amount of ink to the medium P is the second discharge amount smaller than the first discharge amount, it is possible to reliably move the medium P, which is difficult to move due to a large amount of ink discharge, by the paddle  81 . 
     The control unit  80  can control the paddle  81  and the feed roller pair  75  so as to make the circumferential speed of the paddle  81  faster than the circumferential speed of the driving roller  75   a  of the feed roller pair  75 . 
     When it is necessary to rotate the paddle  81  in a state where the medium P is nipped by the feed roller pair  75 , if the circumferential speed of the paddle  81  is slower than the circumferential speed of the feed roller pair  75 , there is a possibility of the medium P being buckled between the paddle  81  and the feed roller pair  75 . By making the circumferential speed of the paddle  81  faster than the circumferential speed of the driving roller, the possibility of the medium P being buckled between the paddle  81  and the feed roller pair  75  can be reduced. 
     The control unit  80  drives the paddle  81  after the upstream end E 2  of the stacked medium P passes the position where the stacked medium receives a feeding force from the feed roller pair  75  illustrated in  FIG. 3 , that is, drives the paddle  81  after the upstream end E 2  of the medium P comes out of the nip of the feed roller pair  75 , thereby capable of avoiding the possibility of the medium P being buckled between the feed roller pair  75  and the paddle  81 . 
     Next, description will be made on control of the paddle  81 , which is performed by the control unit  80  using the type of medium, the temperature and humidity in the installation environment of the apparatus, the discharge amount of ink to the medium P, and the number of stacked media in the stack portion  71 , as the plurality of conditions. 
     For each of a first paper type, a second paper type, and a third paper type having different basis weights as media types, the control unit  80  includes three control tables (first to third tables) according to the discharge amount of ink (recording density), temperature in a dry environment, humidity in a dry environment, and the number of stacked media in the stack portion  71 . The basis weights of the first paper type, the second paper type, and the third paper type are, for example, 60 g/m 2  or more and less than 80 g/m 2  for the first paper type, 80 g/m 2  or more and less than 100 g/m 2 , for the second paper type, and 100 g/m 2  or more for the third paper type. 
     As the temperature and humidity of the installation environment of the apparatus, the temperature and humidity of the room where the recording system  1  is installed can be used. A humidity measurement unit and a temperature measurement unit (not illustrated) may be provided in the recording unit  2  and the measurement results of the measurement units may be used. Although either one of temperature and humidity may be used, in this embodiment, the installation environment of the apparatus is divided into nine sections K 1  to K 9  as illustrated in  FIG. 12  according to the relationship between temperature and humidity in a temperature and humidity environment. 
     Table 3 illustrates an example of a first table which is a control table for the first paper type. Table 4 illustrates an example of a second table which is a control table for the second paper type. Table 5 illustrates an example of a third table which is a control table for the paper type. 
     The first table (Table 3), the second table (Table 4), and the third table (Table 5) represent threshold values for the number of stacked media for determining whether to drive the paddle  81 , which are determined according to classification of the installation environment of the apparatus and the discharge amount of ink (recording density), and the rotation speed of the paddle  81  when driving the paddle  81 . 
     In the first table (Table 3), the second table (Table 4), and the third table (Table 5), the rotation speed of the paddle is divided into, for example, three stages of low speed, medium speed, and high speed. The low speed is a rotation speed slower than the rotation speed of the feed roller pair  75 , the medium speed is equal to the rotation speed of the feed roller pair  75 , and the high speed is a rotation speed faster than the rotation speed of the feed roller pair  75 . The degree of low speed and high speed can be further finely divided and controlled. 
     
       
         
           
               
             
               
                 TABLE 3 
               
               
                   
               
               
                 First table 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
            
               
                   
                 Environment 
               
            
           
           
               
               
               
               
            
               
                   
                 Classification K1 
                 Classification K2 
                 Classification K3 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 Threshold value 
                   
                 Threshold value 
                   
                 Threshold value 
                   
               
               
                   
                 for the number of 
                 Paddle 
                 for the number of 
                 Paddle 
                 for the number of 
                 Paddle 
               
               
                 Recording density (%) 
                 stacked media 
                 speed 
                 stacked media 
                 speed 
                 stacked media 
                 speed 
               
               
                   
               
               
                 0 or more, less than 10 
                 20 secs 
                 low 
                 18 
                 low 
                 16 
                 low 
               
               
                 10 or more, less than 20 
                 18 
                 low 
                 16 
                 low 
                 14 
                 low 
               
               
                 20 or more, less than 30 
                 16 
                 low 
                 14 
                 medium 
                 12 
                 medium 
               
               
                 30 or more, less than 40 
                 14 
                 medium 
                 12 
                 medium 
                 10 
                 medium 
               
               
                 40 or more, less than 50 
                 12 
                 medium 
                 10 
                 medium 
                 5 
                 medium 
               
               
                 50 or more, less than 60 
                 10 
                 medium 
                 5 
                 high 
                 0 
                 high 
               
               
                 60 or more, less than 70 
                 5 
                 high 
                 0 
                 high 
                 0 
                 high 
               
               
                 70 or more, less than 80 
                 0 
                 high 
                 0 
                 high 
                 0 
                 high 
               
               
                 80 or more, less than 90 
                 0 
                 high 
                 0 
                 high 
                 0 
                 high 
               
               
                 90 or more, less than 100 
                 0 
                 high 
                 0 
                 high 
                 0 
                 high 
               
               
                 100 or more 
                 0 
                 high 
                 0 
                 high 
                 0 
                 high 
               
               
                   
               
            
           
           
               
               
            
               
                   
                 Environment 
               
            
           
           
               
               
               
               
            
               
                   
                 Classification K4 
                 Classification K5 
                 Classification K6 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 Threshold value 
                   
                 Threshold value 
                   
                 Threshold value 
                   
               
               
                   
                 for the number of 
                 Paddle 
                 for the number of 
                 Paddle 
                 for the number of 
                 Paddle 
               
               
                 Recording density (%) 
                 stacked media 
                 speed 
                 stacked media 
                 speed 
                 stacked media 
                 speed 
               
               
                   
               
               
                 0 or more, less than 10 
                 20 secs 
                 low 
                 20 secs 
                 low 
                 20 secs 
                 low 
               
               
                 10 or more, less than 20 
                 20 secs 
                 low 
                 20 secs 
                 low 
                 20 secs 
                 low 
               
               
                 20 or more, less than 30 
                 18 
                 low 
                 20 secs 
                 low 
                 20 secs 
                 low 
               
               
                 30 or more, less than 40 
                 16 
                 low 
                 18 
                 low 
                 20 secs 
                 low 
               
               
                 40 or more, less than 50 
                 14 
                 medium 
                 16 
                 low 
                 18 
                 low 
               
               
                 50 or more, less than 60 
                 12 
                 medium 
                 14 
                 medium 
                 16 
                 low 
               
               
                 60 or more, less than 70 
                 10 
                 medium 
                 12 
                 medium 
                 14 
                 medium 
               
               
                 70 or more, less than 80 
                 5 
                 high 
                 10 
                 medium 
                 12 
                 medium 
               
               
                 80 or more, less than 90 
                 0 
                 high 
                 5 
                 high 
                 10 
                 medium 
               
               
                 90 or more, less than 100 
                 0 
                 high 
                 0 
                 high 
                 5 
                 high 
               
               
                 100 or more 
                 0 
                 high 
                 0 
                 high 
                 0 
                 high 
               
               
                   
               
            
           
           
               
               
            
               
                   
                 Environment 
               
            
           
           
               
               
               
               
            
               
                   
                 Classification K7 
                 Classification K8 
                 Classification K9 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 Threshold value 
                   
                 Threshold value 
                   
                 Threshold value 
                   
               
               
                   
                 for the number of 
                 Paddle 
                 for the number of 
                 Paddle 
                 for the number of 
                 Paddle 
               
               
                 Recording density (%) 
                 stacked media 
                 speed 
                 stacked media 
                 speed 
                 stacked media 
                 speed 
               
               
                   
               
               
                 0 or more, less than 10 
                 20 secs 
                 low 
                 20 secs 
                 low 
                 20 secs 
                 low 
               
               
                 10 or more, less than 20 
                 20 secs 
                 low 
                 20 secs 
                 low 
                 20 secs 
                 low 
               
               
                 20 or more, less than 30 
                 20 secs 
                 low 
                 20 secs 
                 low 
                 20 secs 
                 low 
               
               
                 30 or more, less than 40 
                 20 secs 
                 low 
                 20 secs 
                 low 
                 20 secs 
                 low 
               
               
                 40 or more, less than 50 
                 18 
                 low 
                 18 
                 low 
                 18 
                 low 
               
               
                 50 or more, less than 60 
                 16 
                 low 
                 16 
                 low 
                 16 
                 low 
               
               
                 60 or more, less than 70 
                 14 
                 medium 
                 14 
                 low 
                 14 
                 low 
               
               
                 70 or more, less than 80 
                 12 
                 medium 
                 12 
                 medium 
                 12 
                 low 
               
               
                 80 or more, less than 90 
                 10 
                 medium 
                 10 
                 medium 
                 10 
                 medium 
               
               
                 90 or more, less than 100 
                 5 
                 high 
                 5 
                 medium 
                 5 
                 medium 
               
               
                 100 or more 
                 0 
                 high 
                 0 
                 high 
                 0 
                 medium 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 4 
               
               
                   
               
               
                 Second table 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
            
               
                   
                 Environment 
               
            
           
           
               
               
               
               
            
               
                   
                 Classification K1 
                 Classification K2 
                 Classification K3 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 Threshold value 
                   
                 Threshold value 
                   
                 Threshold value 
                   
               
               
                   
                 for the number of 
                 Paddle 
                 for the number of 
                 Paddle 
                 for the number of 
                 Paddle 
               
               
                 Recording density (%) 
                 stacked media 
                 speed 
                 stacked media 
                 speed 
                 stacked media 
                 speed 
               
               
                   
               
               
                 0 or more, less than 10 
                 18 
                 low 
                 16 
                 low 
                 14 
                 low 
               
               
                 10 or more, less than 20 
                 16 
                 low 
                 14 
                 low 
                 12 
                 low 
               
               
                 20 or more, less than 30 
                 14 
                 medium 
                 12 
                 low 
                 10 
                 low 
               
               
                 30 or more, less than 40 
                 12 
                 medium 
                 10 
                 medium 
                 5 
                 low 
               
               
                 40 or more, less than 50 
                 10 
                 medium 
                 5 
                 medium 
                 0 
                 medium 
               
               
                 50 or more, less than 60 
                 5 
                 high 
                 0 
                 medium 
                 0 
                 medium 
               
               
                 60 or more, less than 70 
                 0 
                 high 
                 0 
                 high 
                 0 
                 medium 
               
               
                 70 or more, less than 80 
                 0 
                 high 
                 0 
                 high 
                 0 
                 high 
               
               
                 80 or more, less than 90 
                 0 
                 high 
                 0 
                 high 
                 0 
                 high 
               
               
                 90 or more, less than 100 
                 0 
                 high 
                 0 
                 high 
                 0 
                 high 
               
               
                 100 or more 
                 0 
                 high 
                 0 
                 high 
                 0 
                 high 
               
               
                   
               
            
           
           
               
               
            
               
                   
                 Environment 
               
            
           
           
               
               
               
               
            
               
                   
                 Classification K4 
                 Classification K5 
                 Classification K6 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 Threshold value 
                   
                 Threshold value 
                   
                 Threshold value 
                   
               
               
                   
                 for the number of 
                 Paddle 
                 for the number of 
                 Paddle 
                 for the number of 
                 Paddle 
               
               
                 Recording density (%) 
                 stacked media 
                 speed 
                 stacked media 
                 speed 
                 stacked media 
                 speed 
               
               
                   
               
               
                 0 or more, less than 10 
                 20 secs 
                 low 
                 20 secs 
                 low 
                 20 secs 
                 low 
               
               
                 10 or more, less than 20 
                 18 
                 low 
                 20 secs 
                 low 
                 20 secs 
                 low 
               
               
                 20 or more, less than 30 
                 16 
                 low 
                 18 
                 low 
                 20 secs 
                 low 
               
               
                 30 or more, less than 40 
                 14 
                 medium 
                 16 
                 low 
                 18 
                 low 
               
               
                 40 or more, less than 50 
                 12 
                 medium 
                 14 
                 medium 
                 16 
                 low 
               
               
                 50 or more, less than 60 
                 10 
                 medium 
                 12 
                 medium 
                 14 
                 medium 
               
               
                 60 or more, less than 70 
                 5 
                 high 
                 10 
                 medium 
                 12 
                 medium 
               
               
                 70 or more, less than 80 
                 0 
                 high 
                 5 
                 high 
                 10 
                 medium 
               
               
                 80 or more, less than 90 
                 0 
                 high 
                 0 
                 high 
                 5 
                 high 
               
               
                 90 or more, less than 100 
                 0 
                 high 
                 0 
                 high 
                 0 
                 high 
               
               
                 100 or more 
                 0 
                 high 
                 0 
                 high 
                 0 
                 high 
               
               
                   
               
            
           
           
               
               
            
               
                   
                 Environment 
               
            
           
           
               
               
               
               
            
               
                   
                 Classification K7 
                 Classification K8 
                 Classification K9 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 Threshold value 
                   
                 Threshold value 
                   
                 Threshold value 
                   
               
               
                   
                 for the number of 
                 Paddle 
                 for the number of 
                 Paddle 
                 for the number of 
                 Paddle 
               
               
                 Recording density (%) 
                 stacked media 
                 speed 
                 stacked media 
                 speed 
                 stacked media 
                 speed 
               
               
                   
               
               
                 0 or more, less than 10 
                 20 secs 
                 low 
                 20 secs 
                 low 
                 20 secs 
                 low 
               
               
                 10 or more, less than 20 
                 20 secs 
                 low 
                 20 secs 
                 low 
                 20 secs 
                 low 
               
               
                 20 or more, less than 30 
                 20 secs 
                 low 
                 20 secs 
                 low 
                 20 secs 
                 low 
               
               
                 30 or more, less than 40 
                 18 
                 low 
                 20 secs 
                 low 
                 20 secs 
                 low 
               
               
                 40 or more, less than 50 
                 16 
                 medium 
                 18 
                 low 
                 18 
                 low 
               
               
                 50 or more, less than 60 
                 14 
                 medium 
                 16 
                 medium 
                 16 
                 low 
               
               
                 60 or more, less than 70 
                 12 
                 medium 
                 14 
                 medium 
                 14 
                 medium 
               
               
                 70 or more, less than 80 
                 10 
                 high 
                 12 
                 medium 
                 12 
                 medium 
               
               
                 80 or more, less than 90 
                 5 
                 high 
                 10 
                 high 
                 10 
                 medium 
               
               
                 90 or more, less than 100 
                 0 
                 high 
                 5 
                 high 
                 5 
                 high 
               
               
                 100 or more 
                 0 
                 high 
                 0 
                 high 
                 0 
                 high 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 5 
               
               
                   
               
               
                 Third table 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
            
               
                   
                 Environment 
               
            
           
           
               
               
               
               
            
               
                   
                 Classification K1 
                 Classification K2 
                 Classification K3 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 Threshold value 
                   
                 Threshold value 
                   
                 Threshold value 
                   
               
               
                   
                 for the number of 
                 Paddle 
                 for the number of 
                 Paddle 
                 for the number of 
                 Paddle 
               
               
                 Recording density (%) 
                 stacked media 
                 speed 
                 stacked media 
                 speed 
                 stacked media 
                 speed 
               
               
                   
               
               
                 0 or more, less than 10 
                 20 secs 
                 low 
                 20 secs 
                 low 
                 20 secs 
                 low 
               
               
                 10 or more, less than 20 
                 20 secs 
                 medium 
                 20 secs 
                 low 
                 20 secs 
                 low 
               
               
                 20 or more, less than 30 
                 18 
                 medium 
                 20 secs 
                 medium 
                 18 
                 low 
               
               
                 30 or more, less than 40 
                 16 
                 medium 
                 18 
                 medium 
                 16 
                 medium 
               
               
                 40 or more, less than 50 
                 14 
                 high 
                 16 
                 medium 
                 14 
                 medium 
               
               
                 50 or more, less than 60 
                 12 
                 high 
                 14 
                 high 
                 12 
                 medium 
               
               
                 60 or more, less than 70 
                 10 
                 high 
                 12 
                 high 
                 10 
                 high 
               
               
                 70 or more, less than 80 
                 5 
                 high 
                 10 
                 high 
                 5 
                 high 
               
               
                 80 or more, less than 90 
                 0 
                 high 
                 5 
                 high 
                 0 
                 high 
               
               
                 90 or more, less than 100 
                 0 
                 high 
                 0 
                 high 
                 0 
                 high 
               
               
                 100 or more 
                 0 
                 high 
                 0 
                 high 
                 0 
                 high 
               
               
                   
               
            
           
           
               
               
            
               
                   
                 Environment 
               
            
           
           
               
               
               
               
            
               
                   
                 Classification K4 
                 Classification K5 
                 Classification K6 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 Threshold value 
                   
                 Threshold value 
                   
                 Threshold value 
                   
               
               
                   
                 for the number of 
                 Paddle 
                 for the number of 
                 Paddle 
                 for the number of 
                 Paddle 
               
               
                 Recording density (%) 
                 stacked media 
                 speed 
                 stacked media 
                 speed 
                 stacked media 
                 speed 
               
               
                   
               
               
                 0 or more, less than 10 
                 20 secs 
                 low 
                 20 secs 
                 low 
                 20 secs 
                 low 
               
               
                 10 or more, less than 20 
                 20 secs 
                 low 
                 20 secs 
                 low 
                 20 secs 
                 low 
               
               
                 20 or more, less than 30 
                 20 secs 
                 low 
                 20 secs 
                 low 
                 20 secs 
                 low 
               
               
                 30 or more, less than 40 
                 18 
                 medium 
                 18 
                 low 
                 18 
                 low 
               
               
                 40 or more, less than 50 
                 16 
                 medium 
                 16 
                 medium 
                 16 
                 low 
               
               
                 50 or more, less than 60 
                 14 
                 medium 
                 14 
                 medium 
                 14 
                 medium 
               
               
                 60 or more, less than 70 
                 12 
                 high 
                 12 
                 medium 
                 12 
                 medium 
               
               
                 70 or more, less than 80 
                 10 
                 high 
                 10 
                 high 
                 10 
                 medium 
               
               
                 80 or more, less than 90 
                 5 
                 high 
                 5 
                 high 
                 5 
                 high 
               
               
                 90 or more, less than 100 
                 0 
                 high 
                 0 
                 high 
                 0 
                 high 
               
               
                 100 or more 
                 0 
                 high 
                 0 
                 high 
                 0 
                 high 
               
               
                   
               
            
           
           
               
               
            
               
                   
                 Environment 
               
            
           
           
               
               
               
               
            
               
                   
                 Classification K7 
                 Classification K8 
                 Classification K9 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 Threshold value 
                   
                 Threshold value 
                   
                 Threshold value 
                   
               
               
                   
                 for the number of 
                 Paddle 
                 for the number of 
                 Paddle 
                 for the number of 
                 Paddle 
               
               
                 Recording density (%) 
                 stacked media 
                 speed 
                 stacked media 
                 speed 
                 stacked media 
                 speed 
               
               
                   
               
               
                 0 or more, less than 10 
                 20 secs 
                 low 
                 20 secs 
                 low 
                 20 secs 
                 low 
               
               
                 10 or more, less than 20 
                 20 secs 
                 low 
                 20 secs 
                 low 
                 20 secs 
                 low 
               
               
                 20 or more, less than 30 
                 20 secs 
                 low 
                 20 secs 
                 low 
                 20 secs 
                 low 
               
               
                 30 or more, less than 40 
                 18 
                 low 
                 18 
                 low 
                 18 
                 low 
               
               
                 40 or more, less than 50 
                 16 
                 medium 
                 16 
                 low 
                 16 
                 low 
               
               
                 50 or more, less than 60 
                 14 
                 medium 
                 14 
                 medium 
                 14 
                 low 
               
               
                 60 or more, less than 70 
                 12 
                 medium 
                 12 
                 medium 
                 12 
                 medium 
               
               
                 70 or more, less than 80 
                 10 
                 high 
                 10 
                 medium 
                 10 
                 medium 
               
               
                 80 or more, less than 90 
                 5 
                 high 
                 5 
                 high 
                 5 
                 medium 
               
               
                 90 or more, less than 100 
                 0 
                 high 
                 0 
                 high 
                 0 
                 high 
               
               
                 100 or more 
                 0 
                 high 
                 0 
                 high 
                 0 
                 high 
               
               
                   
               
            
           
         
       
     
     The control unit  80  controls the paddle  81  according to a flowchart illustrated in  FIG. 13 . In step S 41 , the control unit  80  acquires information on the temperature and humidity in the installation environment of the apparatus, the recording density, the number of stacked media in the stack portion  71 , and the type of medium. 
     Subsequently, the process proceeds to step S 42 , it is determined whether the type of medium is the first medium, the second medium, or the third medium. When it is determined in step S 42  that the type of medium is the first medium, the process proceeds to step S 43 , and the paddle  81  is controlled using the first table (Table 3). When it is determined in step S 42  that the type of medium is the second medium, the process proceeds to step S 44 , and the paddle  81  is controlled using the second table (Table 4). When it is determined in step S 42  that the type of medium is the third medium, the process proceeds to step S 45 , and the paddle  81  is controlled using the third table (Table 5). 
     As described above, the control unit  80  can control the paddle  81  more appropriately, and thus can move the medium P toward the alignment portion  76  more appropriately by using, as the conditions, the type of medium, the temperature and humidity in the installation environment of the apparatus, the discharge amount of ink to the medium P, and the number of stacked media in the stack portion  71  and controlling the paddle  81  based on the plurality of conditions. 
     About Paddle Configuration 
     As illustrated in  FIG. 2 , the paddle  81  is provided with a first paddle  81   a  and a second paddle  81   b  which are provided at intervals in the width direction (X-axis direction) intersecting the transport direction (+R direction). In this embodiment, two first paddles  81   a  are provided at intervals in the center in the width direction, and two second paddles  81   b  are provided on both sides of the first paddles. 
     The first paddle  81   a  and the second paddle  81   b  are disposed such that the phases in the circumferential direction of the rotation shaft  82  are different from each other as illustrated in  FIG. 3 . 
     Although the paddle  81  sends the medium P in the transport direction +R by rotating while being in contact with the medium P, a contact angle of the rotating paddle  81  with respect to the medium P changes, and thus a wave (velocity unevenness) may be generated in the transport speed of the medium P. 
     In this embodiment, since two types of paddles (first paddle  81   a  and second paddle  81   b ) whose phases in the circumferential direction of the rotation shaft  82  are different from each other are provided, the wave of the transport speed of the medium P generated by the first paddle  81   a  and the wave of the transport speed generated by the second paddle  81   b  are offset. Accordingly, the transport speed of the medium P can be made uniform as a whole. 
     For example, the first paddle  81   a  and the second paddle  81   b  may be configured such that one first paddle  81   a  is provided at the center in the width direction and the second paddle  81   b  is provided on both sides thereof. It is also possible to provide a third paddle different in phase in the circumferential direction from both of the first paddle  81   a  and the second paddle  81   b.  The third paddle can be provided, for example, further outside in the width direction with respect to the second paddle  81   b.    
     A device obtained by omitting the saddle-stitching function from the second unit  6  as a medium processing apparatus in the first embodiment can be regarded as the medium transport device  70 . Also, an apparatus obtained by omitting the recording function from the recording system  1  can be regarded as the medium transport device  70  or the medium processing apparatus that performs saddle-stitching processing on the medium. 
     The medium transport device  70  can also be employed in a medium processing apparatus that performs not only saddle-stitching processing but also end-stitching processing and punching processing on a bundle of media having aligned ends. 
     Further, it is needless to say that the present disclosure is not limited to the embodiment described above and various modifications may be made thereto within the scope of the disclosure described in the claims, and various modifications are also included in the scope of the present disclosure.