Patent Publication Number: US-11654702-B2

Title: Recording device

Description:
The present application is based on and claims priority from JP Application Serial Number 2020-106784, filed Jun. 22, 2020, the disclosure of which is hereby incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a recording device. 
     2. Related Art 
     In the related art, as indicated in JP-A-2018-197167, a recording device has been known that includes a recording head configured to perform recording on a transported sheet, a discharge roller pair disposed downstream of the recording head in a first transport direction, and configured to transport the sheet in the first transport direction, and a reverse roller pair disposed downstream of the discharge roller pair in the first transport direction, and configured to be able to transport the sheet in a second transport direction different from the first transport direction. 
     In the recording device described above, since the discharge roller pair and the reverse roller pair are driven by the same power source, another new sheet cannot be supplied until reverse transport processing of the reverse roller pair ends even after the transport of the sheet by the discharge roller pair ends, for example, and throughput of printing is reduced. 
     Thus, it is conceivable that the discharge roller pair and the reverse roller pair are configured to be separately driven. With such a configuration, while the sheet is transported in the second transport direction by driving the reverse roller pair in a reverse direction, another new sheet can be transported in the first transport direction by driving the discharge roller pair in a normal direction, and a speed of processing of double-sided printing can be increased. 
     However, in a case of this configuration, when the discharge roller pair and the reverse roller pair are driven in the normal direction and sandwich the same sheet to perform transport processing, there is a problem in that a variation occurs in transport amount of the sheet unless the discharge roller pair and the reverse roller pair are reliably driven in synchronization, and image quality decreases. 
     SUMMARY 
     A recording device includes a recording unit configured to perform recording on a recording medium, a first transport path in which the recording medium is transported in a first direction during recording by the recording unit, a second transport path that is coupled to the first transport path in a position downstream of the recording unit in the first direction, and in which the recording medium on which recording was performed by the recording unit is transported in a second direction different from the first direction in a path different from the first transport path, a first discharge roller pair disposed in a position upstream in the first direction from a coupling position of the first transport path with the second transport path, and configured to sandwich a recording medium on which recording was performed by the recording unit, and transport the recording medium in the first direction, a second discharge roller pair disposed in the coupling position or disposed downstream of the coupling position in the first direction, configured to sandwich the recording medium, and apply a transport force in the first direction to the recording medium in the first transport path and a transport force in the second direction to the recording medium in the second transport path, and formed of a second discharge driving roller and a second discharge driven roller, a first driving motor configured to drive the first discharge driving roller, a second driving motor configured to drive the second discharge driving roller, and a movement mechanism configured to move the second discharge roller pair between a sandwiching state where the second discharge driving roller and the second discharge driven roller sandwich the recording medium, and a separated state where the second discharge driving roller and the second discharge driven roller are separated, wherein the second discharge roller pair is in the separated state in a part of a period in which the recording medium is transported. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is an external perspective view illustrating a configuration of a recording device. 
         FIG.  2    is a side cross-sectional view illustrating the configuration of the recording device. 
         FIG.  3 A  is a perspective view illustrating a configuration of a movement mechanism. 
         FIG.  3 B  is a schematic view illustrating an operation of the movement mechanism. 
         FIG.  3 C  is a schematic view illustrating an operation of the movement mechanism. 
         FIG.  4    is a block diagram illustrating a configuration of a control unit. 
         FIG.  5 A  is a schematic view illustrating a control method of the recording device. 
         FIG.  5 B  is a schematic view illustrating the control method of the recording device. 
         FIG.  5 C  is a schematic view illustrating the control method of the recording device. 
         FIG.  5 D  is a schematic view illustrating the control method of the recording device. 
         FIG.  5 E  is a schematic view illustrating the control method of the recording device. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     A configuration of a recording device  1  will be described.  FIG.  1    is an external perspective view illustrating the configuration of the recording device  1 , and  FIG.  2    is a side cross-sectional view illustrating the configuration of the recording device  1 . 
     As illustrated in  FIG.  1   , the recording device (for example, an inkjet printer)  1  includes a device main body  2 , and a scanner unit  3  provided on an upper portion of the device main body  2 . The recording device  1  is a so-called multifunctional machine. The device main body  2  has a recording function of performing recording on a recording medium S (for example, recording paper). The scanner unit  3  has a function of reading a document. The scanner unit  3  includes an automatic document feeding mechanism (ADF: auto document feeder) that automatically feeds a set document. 
     The device main body  2  includes a transport unit  17  that transports the recording paper, a recording unit  14  being an example of a recoding means, and the like. Further, a cassette  21  that accommodates the recording medium S is provided. In the present embodiment, two cassettes  21  are provided. 
     The device main body  2  includes a cover  7  that opens and closes, and is configured to be able to set and feed the recording medium S with the cover  7  in an open state. 
     The device main body  2  includes an operation unit  5  that performs various operations of the recording device  1  on a front face (surface in a +Y direction) of the device. The operation unit  5  includes a display unit and a plurality of operation buttons, and is provided so as to be able to be tilted. 
     A discharge port  10  through which the recording medium S on which recording is performed is discharged is provided on a lower side of the operation unit  5 , and a discharge tray  6  that receives the discharged recording medium S is provided on the lower side of the discharge port  10 . The discharge tray  6  is provided such that the discharge tray  6  can be in a state of being accommodated inside the device main body  2  and a state of being pulled out from the device main body  2 . 
     As illustrated in  FIG.  2   , the device main body  2  includes an accommodation portion  13 , the recording unit  14 , a support portion  15 , a transport path  16 , the transport unit  17 , and the like. 
     The accommodation portion  13  is configured so as to accommodate the recording medium S. The accommodation portion  13  according to the present embodiment is configured so as to be able to accommodate the cassette  21  that accommodates the recording medium S. The cassette  21  is configured to be detachable from the device main body  2 . The recording device  1  includes a supply mechanism (not illustrated) capable of supplying the recording medium S accommodated in the accommodation portion  13  toward the recording unit  14 . Note that, in  FIG.  2   , a part of the cassette  21  is omitted. 
     The recording unit  14  is configured so as to perform recording on the recording medium S. The recording unit  14  includes a head  22  and a carriage  23 . The head  22  discharges liquid toward the recording medium S. The carriage  23  is equipped with the head  22 , and scans the recording medium S in a direction along an X axis. In other words, the recording device  1  according to the present embodiment is a serial type printer. Note that the recording device  1  may be a line type printer capable of performing recording all at once in a width direction (the direction along the X axis) of the recording medium S. The recording unit  14  performs recording on the recording medium S from above. 
     The support portion  15  faces the recording unit  14 . The support portion  15  supports the recording medium S supplied from the accommodation portion  13 . The support portion  15  supports a portion of the recording medium S recorded by the recording unit  14 . The support portion  15  supports the recording medium S from below. 
     The transport path  16  is a path in which the recording medium S is transported. The transport path  16  includes a first transport path  24  and a second transport path  25 . In  FIG.  2   , a path indicated by a dashed line is the first transport path  24 , and a path indicated by a dot-dash line is the second transport path  25 . 
     The first transport path  24  includes a path in which the recording medium S is transported in a direction corresponding to the +Y direction as a first direction during recording by the recording unit  14 . The first transport path  24  extends from the accommodation portion  13  via the recording unit  14 . The first transport path  24  according to the present embodiment extends between the recording unit  14  and the support portion  15 . Thus, the recording medium S is recorded by the recording unit  14  while being transported in the first transport path  24 . In other words, the recording unit  14  performs recording on the recording medium S in the first transport path  24 . The recorded recording medium S is discharged to the outside of the device main body  2  by being transported in the first transport path  24 . 
     The first transport path  24  according to the present embodiment extends upward from the accommodation portion  13 , and then extends forward (+Y direction) toward the recording unit  14 . Thus, the first transport path  24  according to the present embodiment includes a curved portion  26  being curved. The curved portion  26  is located between the accommodation portion  13  and the recording unit  14  in the first transport path  24 . The recording medium S is transported through the curved portion  26 , and thus a posture of the recording medium S is vertically reversed when being accommodated in the accommodation portion  13  and when facing the recording unit  14 . 
     The second transport path  25  is a path that is coupled to the first transport path  24  in a position downstream of the recording unit  14 , and in which the recording medium S recorded by the recording unit  14  is transported in a direction corresponding to a −Y direction as a second direction different from the direction corresponding to the +Y direction in a path different from the first transport path  24 . Specifically, the second transport path  25  branches in a branch position A 1  (coupling position) from the first transport path  24 . The second transport path  25  according to the present embodiment branches downstream of the recording unit  14  in the first transport path  24 . In other words, the branch position A 1  of the first transport path  24  and the second transport path  25  is located downstream of the recording unit  14  in the first transport path  24 . A flap  39  is provided upstream of the branch position A 1 . When the recording medium S is transported into the second transport path  25 , the recording medium S is fed into the second transport path  25  by raising an end portion in the +Y direction of the flap  39  upward. Note that the flap  39  is driven by a flap drive source (not illustrated) controlled by a control unit  100  (see  FIG.  4   ). 
     The second transport path  25  and the first transport path  24  merge in a merging position A 2  upstream of the recording unit  14 . In other words, the merging position A 2  of the first transport path  24  and the second transport path  25  is located upstream of the recording unit  14  in the first transport path  24 . More specifically, the merging position A 2  is located upstream of the curved portion  26  in the first transport path  24 . 
     The second transport path  25  extends from the branch position A 1  toward the merging position A 2 . The second transport path  25  according to the present embodiment extends below the first transport path  24 . When recording is performed on both sides (in a case of double-sided printing), the recording medium S is transported to the second transport path  25 . 
     The transport unit  17  is configured so as to transport the recording medium S along the transport path  16 . The transport unit  17  according to the present embodiment includes a first transport roller  31 , a second transport roller pair  32 , a first discharge roller pair  33 , a second discharge roller pair  34 , and a relay roller pair  35 . The first transport roller  31 , the second transport roller pair  32 , the first discharge roller pair  33 , the second discharge roller pair  34 , and the relay roller pair  35  rotate to apply a transport force to the recording medium S, and the recording medium S is transported. 
     The first transport roller  31 , the second transport roller pair  32 , the first discharge roller pair  33 , and the second discharge roller pair  34  are located along the first transport path  24 . The first transport roller  31 , the second transport roller pair  32 , the first discharge roller pair  33 , and the second discharge roller pair  34  are located in this order from upstream to downstream in the first transport path  24 . 
     The first transport roller  31  is located upstream of the recording unit  14  in the first transport path  24 . Specifically, the first transport roller  31  is located between the recording unit  14  and the merging position A 2  in the first transport path  24 . The first transport roller  31  transports the recording medium S supplied from the accommodation portion  13  and the recording medium S transported in the second transport path  25 . A circumferential surface of the first transport roller  31  is located along the curved portion  26  in the first transport path  24 . Thus, the curved portion  26  in the first transport path  24  is a portion extending along the circumferential surface of the first transport roller  31 . A plurality of driven rollers  31   b  are disposed on the circumferential surface of the first transport roller  31 , and a transport force is applied to the recording medium S by sandwiching the recording medium S between the first transport roller  31  and the driven roller  31   b.    
     The second transport roller pair  32  is located upstream of the recording unit  14  in the first transport path  24 . The second transport roller pair  32  is located between the recording unit  14  and the first transport roller  31  in the first transport path  24 . The second transport roller pair  32  transports the recording medium S transported by the first transport roller  31  to the recording unit  14  side. The second transport roller pair  32  is formed of a second transport driving roller  32   a  that is driven in rotation, and a second transport driven roller  32   b  that is driven by rotation. A transport force is applied to the recording medium S by sandwiching the recording medium S between the second transport driving roller  32   a  and the second transport driven roller  32   b.    
     The first discharge roller pair  33  is located downstream of the recording unit  14  in the first transport path  24 . Specifically, the first discharge roller pair  33  is located between the recording unit  14  and the branch position A 1  in the first transport path  24 . The first discharge roller pair  33  transports, to the downstream side, the recording medium S transported by the second transport roller pair  32 . The first discharge roller pair  33  is formed of a first discharge driven roller  33   a  that is driven in rotation, and a first discharge driven roller  33   b  that is driven by rotation. A transport force is applied to the recording medium S by sandwiching the recording medium S between the first discharge driving roller  33   a  and the first discharge driven roller  33   b.    
     The second discharge roller pair  34  is disposed in the branch position A 1  downstream of the first discharge roller pair  33  or disposed downstream of the branch position A 1 . In the present embodiment, the second discharge roller pair  34  is disposed downstream of the branch position A 1 . The second discharge roller pair  34  is formed of a second discharge driving roller  34   a  that is driven in rotation, and a second discharge driven roller  34   b  that is driven by rotation. A transport force is applied to the recording medium S by sandwiching the recording medium S between the second discharge driving roller  34   a  and the second discharge driven roller  34   b . The second discharge driven roller  34   b  is, for example, a spurred jagged roller. 
     The second discharge roller pair  34  is configured to sandwich the recording medium S, and be able to apply a transport force in the direction corresponding to the +Y direction to the recording medium S in the first transport path  24 , and a transport force in the direction corresponding to the −Y direction to the recording medium S in the second transport path  25 . 
     Specifically, the second discharge driving roller  34   a  is configured so as to rotate in both directions of a normal direction and a reverse direction. When the second discharge roller pair  34  transports the recording medium S in the direction corresponding to the +Y direction from upstream to downstream in the first transport path  24 , the second discharge driving roller  34   a  rotates in the normal direction. On the other hand, when the transport direction of the recording medium S transported downstream of the first transport path  24  is reversed and the recording medium S is transported in the direction corresponding to the −Y direction in the second transport path  25 , the second discharge driving roller  34   a  rotates in the reverse direction. Note that a counterclockwise direction in  FIG.  2    is the normal direction, and a clockwise direction is the reverse direction. 
     The relay roller pair  35  is located midway along the second transport path  25 . The relay roller pair  35  transports the recording medium S along the second transport path  25  in the direction corresponding to the −Y direction. In other words, the relay roller pair  35  transports the recording medium S from the branch position A 1  toward the merging position A 2  in the second transport path  25 . The relay roller pair  35  is formed of a relay driving roller  35   a  that is driven in rotation, and a relay driven roller  35   b  that is driven by rotation. A transport force is applied to the recording medium S by sandwiching the recording medium S between the relay driving roller  35   a  and the relay driven roller  35   b.    
     In recording (double-sided printing) on both sides of the recording medium S using the first transport path  24  and the second transport path  25 , when recording is performed on a second surface on an opposite side to a first surface of the recording medium S having the first surface being recorded, after recording on the first surface is completed, an upstream end in the transport direction of the recording medium S is transported to the branch position A 1  exceeding a tip portion in the +Y direction of the flap  39  in the direction corresponding to the +Y direction in the first transport path  24 , and is then reversed at the second discharge driving roller  34   a . In this way, the recording medium S is fed into the second transport path  25 . The recording medium S fed into the second transport path  25  is transported to the merging position A 2 , has a surface of the recording medium S reversed by the first transport roller  31 , and is transported such that second surface faces the head  22 . In this way, the liquid is discharged from the head  22  onto the second surface, and double-sided printing of the recording medium S is performed. 
     In the recording device  1  according to the present embodiment, the first discharge driving roller  33   a  and the second discharge driving roller  34   a  are driven by power sources different from each other. 
     Specifically, the first discharge driving roller  33   a  is driven by a first driving motor  111 , and the second discharge driving roller  34   a  is driven by a second driving motor  112  (see  FIG.  4   ). 
     More specifically, the first discharge driving roller  33   a  and the second transport driving roller  32   a  are driven by the first driving motor  111 , and the second discharge driving roller  34   a  and the relay driving roller  35   a  are driven by the second driving motor  112 . The first transport roller  31  is driven by a fourth driving motor  114 . 
     The first discharge driving roller  33   a  and the second discharge driving roller  34   a  are driven by different power sources, and thus the first discharge driving roller  33   a  can be rotated in the normal direction to transport the recording medium S along the first transport path  24 , and the second discharge driving roller  34   a  can also be rotated in the reverse direction to transport the previously recorded recording medium S along the second transport path  25 . In other words, the first discharge driving roller  33   a  and the second discharge driving roller  34   a  are separately driven, and thus a speed of processing of the double-sided printing can be increased. 
     However, when the first discharge roller pair  33  and the second discharge roller pair  34  transport the same recording medium S along the first transport path  24  while sandwiching the recording medium S, there is a problem in that a variation occurs in transport amount of the recording medium S unless the first discharge roller pair  33  and the second discharge roller pair  34  are reliably driven in synchronization, and image quality decreases. 
     Specifically, in a state where the same recording medium S in the first transport path  24  is sandwiched between the second transport roller pair  32 , the first discharge roller pair  33 , and the second discharge roller pair  34 , a transport force of the second transport roller pair  32  to the recording medium S is set higher than a transport force of the other first discharge roller pair  33  and second discharge roller pair  34  to the recording medium S, and thus the transport force of the second transport roller pair  32  becomes dominant, and the recording medium S can be sequentially transported downstream. In other words, in this state, the state of synchronization between the first discharge roller pair  33  and the second discharge roller pair  34  does not affect a transport property of the recording medium S, and the image quality is secured. 
     On the other hand, in a state where the recording medium S is further transported and the same recording medium S is sandwiched between the first discharge roller pair  33  and the second discharge roller pair  34 , the image quality is affected by the synchronization state of the first discharge roller pair  33  and the second discharge roller pair  34 . For example, when a transport speed of the recording medium S by the second discharge roller pair  34  is slower than a transport speed by the first discharge roller pair  33 , a transport amount of the recording medium S is smaller than a theoretical transport amount. Further, when a transport speed of the recording medium S by the second discharge roller pair  34  is faster than a transport speed by the first discharge roller pair  33 , a transport amount of the recording medium S is greater than the theoretical transport amount. Thus, when a variation occurs in transport amount of the recording medium S during recording processing by the recording unit  14 , the image quality decreases. 
     Thus, the recording device  1  according to the present embodiment includes a movement mechanism  60  capable of moving the second discharge roller pair  34  between a sandwiching state where the second discharge driving roller  34   a  and the second discharge driven roller  34   b  sandwich the recording medium S, and a separated state where the second discharge driving roller  34   a  and the second discharge driven roller  34   b  are separated. Then, in a part of a period, the second discharge roller pair  34  is configured to be movable into the separated state. In this way, for example, during the transport of the recording medium S, the second discharge roller pair  34  is movable into the separated state in a part of a period in which the image quality is considered to be affected. In this way, the first discharge roller pair  33  and the second discharge roller pair  34  do not interfere with each other in the transport of the recording medium S. In other words, synchronization is disabled. Therefore, a transport failure of the recording medium S can be reduced, and the image quality can be improved. 
     Next, a configuration of the movement mechanism  60  will be described. 
       FIG.  3 A  is a perspective view illustrating a configuration of the movement mechanism  60 .  FIGS.  3 B and  3 C  are schematic views each illustrating an operation of the movement mechanism  60 .  FIG.  3 B  illustrates a sandwiching state of the second discharge roller pair  34 .  FIG.  3 C  illustrates a separated state of the second discharge roller pair  34 . 
     As illustrated in  FIG.  3 A , the movement mechanism  60  includes an eccentric cam  61 , and a slide cam  63  that interlocks with the eccentric cam  61 . 
     The eccentric cam  61  includes a cylindrical portion  61   a  having a cylindrical shape, and a rotary shaft  61   b  provided in a position shifted from a center point of the cylindrical portion  61   a  in a side view. By rotating the rotary shaft  61   b , an outer peripheral surface of the cylindrical portion  61   a  eccentrically moves about the rotary shaft  61   b . The rotary shaft  61   b  is driven in rotation by a third driving motor  113  (see  FIG.  4   ) as a driving motor. 
     The outer peripheral surface of the cylindrical portion  61   a  is held in contact with the slide cam  63 . The slide cam  63  is biased toward the cylindrical portion  61   a  by a spring (not illustrated). 
     Then, the slide cam  63  is movable in the direction along the Y-axis by the eccentric movement of the eccentric cam  61 . 
     A part of the slide cam  63  is provided with an inclined surface  63   a . The surface  63   a  is configured to be able to contact a rotary shaft  34   c  of the second discharge driven roller  34   b  as the slide cam  63  moves in the direction along the Y-axis. Note that the rotary shaft  34   c  of the second discharge driven roller  34   b  is biased in a −Z direction by a compression spring  69  installed on a top plate  68  provided above the second discharge driven roller  34   b.    
     Then, the slide cam  63  moves in the +Y direction, and the surface  63   a  of the slide cam  63  slidably moves in contact with the rotary shaft  34   c  of the second discharge driven roller  34   b , and thus, as illustrated in  FIG.  3 C , the second discharge driven roller  34   b  enters the separated state of being separated from the second discharge driving roller  34   a . In the separated state, the second discharge driven roller  34   b  and the second discharge driving roller  34   a  are in a state of being separated by, for example, 1 mm to several mm. 
     On the other hand, the slide cam  63  moves in the −Y direction, and thus the surface  63   a  of the slide cam  63  is separated from the rotary shaft  34   c . Thus, as illustrated in  FIG.  3 B , the second discharge driven roller  34   b  contacts the second discharge driving roller  34   a  and enters the sandwiching state. The movement mechanism  60  is disposed on both ends of the rotary shaft  34   c  extending in a direction along the X-axis, for example. 
     In this way, the movement mechanism  60  can achieve the sandwiching sate and the separated state with a relatively easy structure. 
     Note that the eccentric cam  61  may have a configuration in which a solenoid is used instead of the third driving motor  114 . Furthermore, the eccentric cam  61  may be configured to vertically move the rotary shaft  34   c  by a solenoid. 
     Next, a configuration of the control unit  100  of the recording device  1  will be described.  FIG.  4    is a block diagram illustrating the configuration of the control unit  100  of the recording device  1 . 
     As illustrated in  FIG.  4   , the control unit  100  includes a CPU  101 , a memory  102 , a control circuit  103 , and an I/F (interface)  104 . The CPU  101  is an arithmetic processing device. The memory  102  is a storage device that secures a region for storing a program of the CPU  101 , a working region, or the like, and includes a storage element such as a RAM and an EEPROM. When a print job is acquired from the outside via the I/F  104 , the CPU  101  controls, via the control circuit  103 , the recording unit  14 , the first driving motor  111  (the second transport driving roller  32   a  and the first discharge driving roller  33   a ), the second driving motor  112  (the second discharge driving roller  34   a  and the relay driving roller  35   a ), the third driving motor  113  (the eccentric cam  61 ), and the fourth driving motor  114  (the first transport roller  31 ) according to a program stored in the memory  102 . 
     In the present embodiment, the control unit  100  causes the second discharge roller pair  34  to be in the separated state in a part of a period with, as the part of period, a period in which recording is performed on the recording medium S by the recording unit  14 . For example, the control unit  100  recognizes, as a part of a period, a processing period by the recording unit  14  included in a print job, and performs control. In this way, during the recording processing on the recording medium S by the recording unit  14 , the second transport roller pair  32  and the first discharge roller pair  33  transports the recording medium S. In other words, during the recording processing on the recording medium S, the second discharge roller pair  34  does not take part in the transport of the recording medium S. In this way, a transport failure of the recording medium S during the recording processing can be reduced, and the image quality can be improved. 
     Furthermore, the control unit  100  moves the second discharge roller pair  34  from the separated state to the sandwiching state after the recording processing on the recording medium S by the recording unit  14  ends. At this time, the second discharge driving roller  34   a  is rotated in the normal direction. In this way, the second discharge roller pair  34  sandwiches the recording medium S, and applies a transport force in the direction corresponding to the +Y direction. 
     Further, in a case of double-sided printing, the control unit  100  rotates the second discharge driving roller  34   a  in the reverse direction when the upstream end in the transport direction of the recording medium S exceeds the branch position A 1 . The determination of whether the branch position A 1  is exceeded is performed on the basis of, for example, a detection result from a sensor that detects presence or absence of the recording medium S on the downstream side of the branch position A 1 . In this way, a transport force in the direction corresponding to the −Y direction along the second transport path  25  is applied to the recording medium S. In other words, the second discharge roller pair  34  is in the sandwiching state in a period that does not affect the image quality in the transport of the recording medium S, and can reliably transport the recording medium S. 
     Next, a control method of the recording device  1  will be described. Specifically, a control method of the first discharge roller pair  33  and the second discharge roller pair  34  in double-sided printing processing will be described. 
       FIGS.  5 A to  5 E  are schematic views each illustrating the control method of the recording device  1 . 
     As illustrated in  FIG.  5 A , when the control unit  100  acquires a print job, the control unit  100  transports a recording medium S 1  (S) along the first transport path  24 . Then, recording processing is performed by the recording unit  14 . 
     When the recording processing by the recording unit  14  starts, the movement mechanism  60  is driven, and the second discharge roller pair  34  is moved into the separated state. 
     Next, as illustrated in  FIG.  5 B , the recording medium S 1  is further transported downstream while recording is performed. In a recording processing period (a part of a period) by the recording unit  14 , the second discharge roller pair  34  is in the separated state, and the recording medium S 1  passes between the second discharge driving roller  34   a  and the second discharge driven roller  34   b . Note that, even when the second discharge roller pair  34  is in the separated state, the second discharge driving roller  34   a  is driven in rotation in the normal direction. The reason is to reduce a transport load on the recording medium S 1  when the second discharge roller pair  34  moves from the separated state to the sandwiching state. 
     Next, as illustrated in  FIG.  5 C , when the processing period (the part of the period) by the recording unit  14  included in the print job ends, the control unit  100  moves the second discharge roller pair  34  from the separated state to the sandwiching state. 
     In this way, the first discharge roller pair  33  and the second discharge roller pair  34  transport the recording medium S 1  downstream. 
     Next, as illustrated in  FIG.  5 D , when the control unit  100  determines that an upstream end in the transport direction of the recording medium S 1  exceeds the branch position A 1 , the control unit  100  rotates the second discharge driving roller  34   a  in the reverse direction. The recording medium S 1  is drawn into the second transport path  25  and transported in the direction corresponding to the −Y direction. 
     Further, the control unit  100  transports a new recording medium S 2  (second recording medium) along the first transport path  24  on the basis of a next print job. Then, the recording processing is performed by the recording unit  14 . 
     When the control unit  100  performs transport driving on the recording medium S 1  to the second transport path  25  in the second discharge roller pair  34 , the control unit  100  prioritizes the transport driving of the recording medium S 1  even at timing at which the recording processing on the new recording medium S 2  starts. In other words, the sandwiching state is held. 
     Next, as illustrated in  FIG.  5 E , when the recording medium S 1  deviates from the second discharge roller pair  34 , the control unit  100  moves the second discharge roller pair  34  from the sandwiching state to the separated state. Then, the second discharge driving roller  34   a  is rotated in the normal direction. 
     Note that the recording medium S 1  drawn into the second transport path  25  is transported toward the merging position A 2  by the relay roller pair  35 . 
     Subsequently, the recording medium S 1  is transported in the first transport path  24  with the front and back surfaces being inverted by the first transport roller  31 , and is recorded by the recording unit  14 . In this way, double-sided printing of the recording medium S 1  is performed. 
     As described above, according to the control method of the recording device  1 , in a recording processing period of the recording medium S 1 , the second discharge roller pair  34  is moved into the separated state, and does not take part in transport of the recording medium S 1 . In this way, the recording medium S 1  is transported by a fixed amount, and the image quality can be improved. 
     Further, the first discharge roller pair  33  and the second discharge roller pair  34  are driven by different driving sources, and thus a speed of double-sided printing can be increased. 
     Note that, in the description above, the movement mechanism  60  is driven on the basis of a print job, and the second discharge roller pair  34  is moved between the sandwiching state and the separated state, but the present disclosure is not limited thereto. For example, a sensor that detects presence or absence of the recording medium S may be provided between the head  22  above the first transport path  24  and the first discharge roller pair  33 , and the movement mechanism  60  may be driven according to acquisition information of the sensor. Even with this configuration, similar advantages as described above can be obtained.