JP2017075041A - Printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printer which can suppress deterioration in the printing quality in a case where printing is performed to a medium undone from a roll body.SOLUTION: A control unit of a printer 10 causes a printing operation for performing printing to a conveyed medium M after causing an initial conveyance operation for conveying the medium M so that the tip of the medium M is located at a reference position P4 on the downstream side with respect to a first conveyance unit 31 in the conveyance direction F. When causing the printing operation, the control unit reduces the tension that acts on the medium M conveyed between the first conveyance unit 31 and a delivery unit 20 in comparison to a case of causing the initial conveyance operation.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a printing apparatus such as an ink jet printer.

  Conventionally, a medium that has been provided with a feeding unit that feeds out the medium from a roll body on which a medium such as paper is wound, and a conveyance unit that conveys the medium drawn out from the feeding unit, and that is conveyed in a state in which tension is applied. A printing apparatus that performs printing is known (for example, Patent Document 1).

JP 2014-28700 A

  By the way, in the above printing apparatus, when printing on a medium, the medium may be skewed due to variations in the tension acting on the medium in the width direction intersecting the medium conveyance direction. As a result, printing is performed on the skewed medium, which may reduce the print quality.

  The present invention has been made in view of the above circumstances. An object of the present invention is to provide a printing apparatus that can suppress a decrease in print quality when printing is performed on a medium unrolled from a roll body.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
A printing apparatus that solves the above problems includes a feeding unit that feeds the medium by rotating a roll body on which the medium is wound, a transport unit that transports the medium fed by the feeding unit in a transport direction, and the transport unit includes: The printing unit that performs printing on the transported medium, the transport amount of the medium of the transport unit, and the feeding amount of the medium of the feeding unit, and the transported between the transport unit and the feeding unit A control unit that adjusts a tension acting on the medium, and the control unit transports the medium so that a leading end of the medium is positioned at a reference position downstream of the transport unit in the transport direction. A printing operation for performing printing on the medium to be transported is performed after the transporting operation. When the printing operation is performed, the transporting unit and the feeding unit are performed more than when the initial transporting operation is performed. Carry between departments To reduce the tension applied to the medium to be.

  At the start of the initial transport operation, the length of the medium located downstream from the transport unit in the transport direction tends to be short. For this reason, since the length from the transport unit to the leading edge of the medium is short, the posture of the medium located downstream from the transport unit is likely to change, and tension is applied to the medium transported between the transport unit and the feeding unit. If the medium is transported without being wrinkled, wrinkles are likely to occur in the portion of the medium transported by the transport unit.

  Further, when performing a printing operation, the length of the medium located downstream of the transport unit in the transport direction tends to be long. For this reason, since the length from the transport unit to the front end of the medium is long, the posture of the medium located on the downstream side of the transport unit is hardly changed, and even if the medium is transported without applying tension in the transport direction, the medium The wrinkles are less likely to occur in the parts conveyed by the conveying unit.

  According to the above configuration, when the initial transport operation is performed, the tension acting on the medium transported between the transport unit and the feeding unit is relatively increased. For this reason, even when the medium is transported in a state where the length in the transport direction of the medium positioned downstream from the transport unit is short, wrinkles are suppressed from being generated in the portion of the medium transported by the transport unit. .

  Further, when performing the printing operation, the tension acting on the medium conveyed between the conveying unit and the feeding unit is made relatively small. For this reason, the variation in the width direction of the conveyance amount of the medium based on the variation in the width direction of the tension acting on the medium conveyed between the conveyance unit and the feeding unit is suppressed, and the medium conveyed by the conveyance unit is skewed. It is suppressed.

  Thus, when the initial transport operation is performed, the generation of wrinkles is suppressed, and it is possible to prevent the print quality from being deteriorated due to the wrinkles generated on the medium before the start of the printing operation. Further, when performing a printing operation, it is possible to suppress the skew of the medium accompanying the conveyance of the medium, and to suppress a decrease in print quality due to the skew of the medium. Therefore, when printing is performed on a medium unrolled from the roll body, it is possible to suppress a decrease in print quality.

  In the printing apparatus, when the transport unit is a first transport unit, the medium that is provided between the first transport unit and the feeding unit and is fed from the feeding unit is the first transport unit. A second transport unit that transports toward the first transport unit, wherein the control unit transports the medium in the first transport unit, transports the medium in the second transport unit, and the feeding unit. It controls the feeding amount of the medium to adjust the tension acting on the medium conveyed between the first conveying unit, the second conveying unit, and the feeding unit, and performs the printing operation. The medium transported between the first transport unit and the second transport unit by applying tension acting on the medium transported between the second transport unit and the feeding unit. It is desirable that the tension be larger than the tension acting on the.

  According to the above configuration, when the printing operation is performed, the tension applied to the medium transported between the first transport unit and the second transport unit is relatively reduced, so that the medium transported by the transport unit is reduced. The skew can be suppressed. In addition, when performing a printing operation, the tension applied to the medium conveyed between the second conveyance unit and the feeding unit is relatively increased, so that the medium wound around the roll body is unintentionally wound by its own weight. Unraveling can be suppressed.

  In the printing apparatus, the second transport unit includes a second drive roller that applies a transport force to the medium, a second driven roller that sandwiches the medium together with the second drive roller, and the second A second adjusting unit that adjusts an interval between the driving roller and the second driven roller, and the interval when the second driving roller and the second driven roller sandwich the medium. When the control unit causes the printing operation to be performed when the first interval is set to the second interval when the second driving roller and the second driven roller do not sandwich the medium. In the case where the interval in the second transfer unit is set to the first interval, and the initial transfer operation is performed, the interval in the second transfer unit is set as the second interval. Hope is .

  When performing the initial transport operation, if the distance between the second drive roller and the second driven roller is the first distance that can sandwich the medium, the transport amount of the medium of the first transport unit and the medium of the feeding unit In addition to the feed amount, it is necessary to control the transport amount of the medium in the second transport unit. That is, if the transport amount corresponding to the transport amount of the medium of the first transport unit and the transport amount of the feeding unit medium is not transported by the second transport unit, it is between the first transport unit and the second transport unit or the second transport unit. There is a possibility that tension does not act on the medium conveyed between the two conveying units and the feeding unit.

  In this regard, according to the above configuration, when the initial transport operation is performed, the interval between the second drive roller and the second driven roller is the second interval where the medium cannot be sandwiched. When the tension is applied to the medium conveyed between the feeding units, it is only necessary to control the medium conveyance amount of the first conveyance unit and the medium feeding amount of the feeding unit. Therefore, when the initial transport operation is performed, the control configuration can be simplified because the amount of transport of the medium in the second transport unit need not be controlled.

  In the above-described printing apparatus, the feeding unit can take up the medium by rotating the roll body in the reverse direction to the feeding of the medium, and the control unit, before the initial transport operation, A forward transporting operation of transporting the medium in the transporting direction as the medium is fed out by the feeding unit, and a transporting of the medium in a direction opposite to the transporting direction as the medium is wound up by the feeding unit. In the case of performing the skew feeding operation including the reverse transport operation, it is preferable that the interval in the second transport unit is the second interval. .

  According to the above configuration, the skew feeding operation including the forward transport operation of feeding the medium and transporting the medium in the transport direction, and the reverse transport operation of winding the medium and transporting the medium in the direction opposite to the transport direction is performed. By doing so, the skew of the medium can be eliminated.

  In the above configuration, when the skew feeding operation is performed, the interval between the second driving roller and the second driven roller is the second space where the medium cannot be sandwiched. It is not necessary to control the amount of medium transported by the second transport unit, and the control configuration can be simplified.

In the printing apparatus, it is preferable that the control unit loosens the medium conveyed between the first conveyance unit and the second conveyance unit when the printing operation is performed.
According to the above configuration, when performing a printing operation, tension hardly acts on the medium transported between the first transport unit and the second transport unit. For this reason, when performing a printing operation, the variation in the conveyance direction of the medium in the width direction is further suppressed, and the skew of the medium can be further suppressed.

1 is a side sectional view of a printing apparatus according to an embodiment. The partial top view of the said printing apparatus. FIG. 2 is a block diagram showing an electrical configuration of the printing apparatus. FIG. 3 is a schematic diagram illustrating the operation of the printing apparatus. FIG. 3 is a schematic diagram illustrating the operation of the printing apparatus. FIG. 3 is a schematic diagram illustrating the operation of the printing apparatus. FIG. 3 is a schematic diagram illustrating the operation of the printing apparatus. FIG. 3 is a schematic diagram illustrating the operation of the printing apparatus. FIG. 3 is a schematic diagram illustrating the operation of the printing apparatus. FIG. 3 is a schematic diagram illustrating the operation of the printing apparatus.

  Hereinafter, an embodiment of a printing apparatus will be described with reference to the drawings. The printing apparatus according to the present embodiment is an ink jet large format printer that forms characters and images by ejecting ink onto a long medium.

  As illustrated in FIG. 1, the printing apparatus 10 includes a feeding unit 20 that feeds out the medium M wound around the roll body R along a conveyance direction of the medium M, a conveyance unit 30 that conveys the medium M, and a medium M. Are provided, a support unit 40 that supports the printing medium 50, a printing unit 50 that performs printing on the medium M, and a cutting unit 60 that cuts the printed medium M.

  In the following description, the width direction of the printing apparatus 10 is “width direction X”, the transport direction of the medium M is “transport direction F”, and the upstream side and the downstream side along the transport direction F are referred to. . Further, the width direction X and the conveyance direction F are directions that intersect (orthogonal) each other.

  As shown in FIGS. 1 and 2, the feeding unit 20 includes a holding unit 21 that holds the roll body R on which the medium M is wound, a feeding motor 22 that rotates the roll body R held by the holding unit 21, and It has. The holding unit 21 cannot move the roll body R in the width direction X, and holds the roll body R so that the width direction X can be rotated about the rotation axis direction. The feeding unit 20 drives the feeding motor 22 to rotate the roll body R in the first rotation direction R1 to feed the medium M from the roll body R, while the roll body R is moved in the second rotation direction R2. By rotating, the medium M is wound around the roll body R.

  As shown in FIGS. 1 and 2, the transport unit 30 includes a first transport unit 31 that transports the medium M, and a medium M that has been fed from the feed unit 20 upstream of the first transport unit 31. A second transport unit 32 that transports toward one transport unit 31, and a relay unit 33 that relays transport of the medium M between the first transport unit 31 and the second transport unit 32. . Further, the transport unit 30 includes a first medium detection unit 34 and a second medium detection unit 35 that detect the presence or absence of the medium M.

  As shown in FIG. 2, the first transport unit 31 sandwiches (supports by sandwiching) the medium M together with the first drive roller 311 that imparts transport force to the medium M and the first drive roller 311. 1 driven roller 312 and a first transport motor 313 that drives the first drive roller 311. The first transport unit 31 includes a first adjustment unit 314 that adjusts the distance between the first drive roller 311 and the first driven roller 312. The first driving roller 311 and the first driven roller 312 are rotatably supported with the width direction X as the rotation axis direction. The first drive roller 311 is provided so as to be able to contact the back surface of the medium M, and the first driven roller 312 is provided so as to be able to contact the surface of the medium M.

  The second transport unit 32 includes a second drive roller 321 that applies a transport force to the medium M, a second driven roller 322 that sandwiches the medium M together with the second drive roller 321, and a second drive roller 321. And a second adjustment unit 324 that adjusts the distance between the second drive roller 321 and the second driven roller 322. The second driving roller 321 and the second driven roller 322 are rotatably supported with the width direction X as the rotation axis direction. The second driving roller 321 is provided so as to be able to contact the back surface of the medium M, and the second driven roller 322 is provided so as to be able to contact the surface of the medium M.

  Note that the first adjustment unit 314 of the first transport unit 31 may be realized by a cam mechanism or the like, for example. As an example, in the 1st conveyance part 31, the 1st with respect to the 1st drive roller 311 is pushed up and pushed down by rotating the rotating shaft of the 1st driven roller 312 of the 1st conveyance part 31 with the surrounding surface of a cam. The relative position of the driven roller 312 may be changed. The same applies to the second transport unit 32.

  In the following description, the first driving roller 311, the first driven roller 312, the second driving roller 321, and the second driven roller 322 can sandwich the medium M. The interval between 311 and the first driven roller 312 and the interval between the second drive roller 321 and the second driven roller 322 are referred to as “first interval D1”.

  In addition, the first driving roller 311 and the first driven roller 312, and the second driving roller 321 and the second driven roller 322 when the medium M cannot be held between the first driving roller 311 and the first driven roller 311. The interval between the driven rollers 312 and the interval between the second drive roller 321 and the second driven roller 322 are referred to as a “second interval D2”.

  The relay unit 33 includes a first relay roller 331 provided on the first transport unit 31 side in the transport direction F, and a second relay roller 332 provided on the second transport unit 32 side in the transport direction F. Have. The first relay roller 331 and the second relay roller 332 are rotatably supported with the width direction X as the rotation axis direction. Further, the first relay roller 331 and the second relay roller 332 are provided between the first transport unit 31 and the second transport unit 32 so that the path for transporting the medium M is a curved path. Yes.

  When the transport unit 30 transports the medium M, the transport unit 30 drives the first transport motor 313 while holding the medium M between the first drive roller 311 and the first driven roller 312, The second transport motor 323 is driven in a state where the medium M is sandwiched between the second drive roller 321 and the second driven roller 322.

  The first rotation direction R1, which is the rotation direction of the roll body R when the feeding unit 20 feeds the medium M, is such that the first transport unit 31 and the second transport unit 32 transport the medium M in the transport direction F. It is also the rotation direction of the first drive roller 311 and the second drive roller 321 when The second rotation direction R2, which is the rotation direction of the roll body R when the feeding unit 20 winds up the medium M, is the first conveyance unit 31 and the second conveyance unit 32 in the conveyance direction F. Is also the rotational direction of the first drive roller 311 and the second drive roller 321 when transported in the opposite direction.

  As shown in FIGS. 1 and 2, the first medium detection unit 34 is provided between the relay unit 33 and the second transport unit 32 in the transport direction F, and the second medium detection unit 35 is transported. In the direction F, it is provided between the first transport unit 31 and the relay unit 33. The first medium detection unit 34 detects whether or not the leading end of the medium M has reached the first position P1 between the relay unit 33 and the second transport unit 32, or the medium at the first position P1. Or whether M is present or not. In addition, the second medium detection unit 35 detects whether or not the leading end of the medium M has reached the second position P2 between the first transport unit 31 and the relay unit 33, or the second position P2. It is detected whether or not the medium M is present. The first position P1 and the second position P2 are positions on the conveyance path of the medium M.

  Note that the first medium detection unit 34 and the second medium detection unit 35 may be, for example, reflective optical sensors. According to this, the first position P1 or the second position P2 is irradiated with light, the intensity of the reflected light is detected, and the first position P1 or the second position is detected based on the intensity of the reflected light. It is possible to determine whether or not the medium M exists in P2.

  As shown in FIG. 1, the support unit 40 includes a support base 41 that supports the medium M, a gas chamber 42 that is formed using the support base 41 as a part of a wall, and a negative pressure chamber 43 that communicates with the gas chamber 42. And a suction fan 44 for sucking gas from the negative pressure chamber 43.

  As shown in FIG. 2, the support base 41 has a plate shape in which the width direction X is the longitudinal direction and the transport direction F is the short direction. A plurality of suction holes 45 communicating with the gas chamber 42 are formed through the support base 41. The plurality of suction holes 45 are provided so as to be aligned in the longitudinal direction and the short direction of the support base 41.

  The support unit 40 drives the suction fan 44 to suck the gas from the negative pressure chamber 43 and set the pressure in the negative pressure chamber 43 to a negative pressure. Then, the pressure of the gas chamber 42 communicating with the negative pressure chamber 43 also becomes a negative pressure. As a result, as the gas flows into the gas chamber 42 through the suction hole 45 communicating with the gas chamber 42, an adsorption force that adsorbs the medium M to the support base 41 acts. Thus, the support unit 40 stabilizes the posture of the medium M supported on the support base 41. Note that when the suction fan 44 is driven, gas flows through the support portion 40 as indicated by a two-dot chain line arrow in FIG.

  As shown in FIGS. 1 and 2, the printing unit 50 includes an ejection unit 51 that ejects ink, a third medium detection unit 52 that detects the presence or absence of the medium M, a carriage 53 that holds the ejection unit 51, And a guide shaft 54 that supports the carriage 53 so as to be reciprocally movable in the width direction X. As shown in FIG. 3, the printing unit 50 includes a carriage motor 55 serving as a drive source when the carriage 53 is moved in the width direction X.

  The ejection unit 51 is a so-called ejection head in which a plurality of nozzles that eject ink are formed. In the printing unit 50, the reciprocating area of the carriage 53 in the width direction X is an area facing the support base 41. Further, the third medium detection unit 52 may be a reflective optical sensor, for example, similarly to the first medium detection unit 34 and the second medium detection unit 35.

  Although not shown, the carriage 53 and the carriage motor 55 are connected by a conversion mechanism that converts the rotational movement of the output shaft of the carriage motor 55 into a linear movement in the width direction X of the carriage 53. . As an example, the conversion mechanism may be realized by connecting the carriage 53 to a part of a belt wound around a pulley that is rotationally driven by the carriage motor 55.

  Then, the printing unit 50 performs a discharge operation for discharging ink from the discharge unit 51 toward the surface of the medium M supported by the support base 41 while moving the carriage 53 in the width direction X. Print.

Next, the electrical configuration of the printing apparatus 10 will be described with reference to FIG.
As shown in FIG. 3, the printing apparatus 10 includes a control unit 70 that controls the apparatus in an integrated manner. The control unit 70 is a so-called microcomputer having a CPU, a ROM, a RAM, and the like. Further, the input side interface of the control unit 70 includes a feeding motor 22, a first transport motor 313, a second transport motor 323, a first medium detection unit 34, a second medium detection unit 35, and a third medium. A detection unit 52 is connected. On the other hand, the output side interface of the control unit 70 includes a feeding motor 22, a first transport motor 313, a first adjustment unit 314, a second transport motor 323, a second adjustment unit 324, a suction fan 44, and a discharge unit. 51, the carriage motor 55 and the cutting part 60 are connected.

  Then, the control unit 70 controls driving of the feeding motor 22, the first transport motor 313, and the second transport motor 323, thereby controlling the direction in which the medium M is transported and the transport amount of the medium M. Further, in the present embodiment, the control unit 70 controls the transport amount of the medium M of the first transport unit 31, the transport amount of the medium M of the second transport unit 32, and the feed amount of the medium M of the feeding unit 20. Thus, the tension acting along the transport direction F on the medium M transported between the first transport unit 31, the second transport unit 32, and the feeding unit 20 is adjusted. Specifically, the control unit 70 adjusts the tension by controlling the rotation amounts (rotation angles) of the first transport motor 313, the second transport motor 323, and the feeding motor 22.

  For example, the control unit 70 reduces the transport amount of the medium M of the first transport unit 31 to be smaller than the transport amount of the medium M of the second transport unit 32, so that the first transport unit 31 and the second transport are performed. The tension acting in the transport direction F on the medium M transported between the units 32 is gradually reduced. Further, the control unit 70 conveys between the second conveyance unit 32 and the feeding unit 20 by making the conveyance amount of the medium M of the second conveyance unit 32 larger than the feeding amount of the medium M of the feeding unit 20. The tension acting on the medium M in the transport direction F is gradually increased.

  In addition, the control unit 70 equalizes the transport amount of the medium M of the first transport unit 31 and the transport amount of the medium M of the second transport unit 32, so that the first transport unit 31 and the second transport unit 32. The tension acting in the transport direction F on the medium M transported between the sections 32 is kept constant. In the following description, the tension acting on the medium M in the transport direction F means that the description of the direction in which the tension acts is omitted and the tension acts on the medium M simply.

  Incidentally, the magnitude of the tension acting on the medium M may be estimated based on the loads applied to the first transport motor 313, the second transport motor 323, and the feeding motor 22. For this reason, when it is desired to increase the tension applied to the medium M, the rotation of the first transport motor 313 is performed so that the load applied to the first transport motor 313, the second transport motor 323, and the feeding motor 22 is increased. The amount, the rotation amount of the second transport motor 323, and the rotation amount of the feeding motor 22 may be adjusted.

  By the way, in the delivery part 20, when the outer diameter of the roll body R is small, compared with the case where the outer diameter of the roll body R is large, the roll body R is changed to the first rotational direction R1 or the second rotational direction R2. The amount of feeding or winding of the medium M when it is rotated once is reduced. For this reason, when the outer diameter of the roll body R is small, the control unit 70 increases the amount of rotation of the roll body R as compared with the case where the outer diameter of the roll body R is large. A change in the feeding amount or winding amount of the medium M accompanying a change in the outer diameter is suppressed.

  Further, the transport amount of the medium M is calculated based on the rotation amount of the first drive roller 311 (first transport motor 313) and the outer diameter of the first drive roller 311, or the second drive roller 321 ( Calculation may be performed based on the rotation amount of the first transport motor 323) and the outer diameter of the second drive roller 321. Further, the feeding amount of the medium M may be calculated based on the rotation amount of the roll body R (feeding motor 22) of the feeding unit 20 and the outer diameter of the roll body R. Note that when the medium M is not slack between the first transport unit 31, the second transport unit 32, and the feeding unit 20, the transport amount and the feed amount are equal.

  The control unit 70 alternately performs a unit transport operation for transporting the medium M in the transport direction F by a unit transport amount and a discharge operation for discharging the ink to the discharge unit 51 while moving the carriage 53 in the width direction X. The printing operation to be performed is performed. Here, the unit transport amount is the length in the transport direction F of the discharge unit 51, more precisely, the length not more than the length in the transport direction F of the nozzle row formed in the discharge unit 51 across the transport direction F. That's it.

  In the present embodiment, the control unit 70 sets a state in which the roll M can be printed on the medium M unrolled from the roll R before the roll unit R is newly set in the feeding unit 20 and before the printing operation is performed. Accordingly, various configurations of the printing apparatus 10 are caused to perform an “initialization operation” and an “initial conveyance operation”.

  In the initialization operation, for example, when the remaining amount of the medium M wound around the roll body R newly set in the feeding unit 20, the length of the medium M in the width direction X, and the roll body R are rotated. A “detection estimation operation” for detecting and estimating a load applied to the feeding motor 22 is included. Further, the initialization operation includes a “skew take-off operation” for eliminating the skew feed in which the medium M unwound from the roll body R is transported obliquely with respect to the transport direction F.

  On the other hand, the initial transport operation is an operation of transporting the medium M so that the front end of the medium M is positioned at the reference position P4 on the downstream side of the second transport unit 32. The reference position P4 is a position that serves as a reference for positioning the medium M when printing on the medium M is started.

  Next, the operation of the printing apparatus 10 according to the present embodiment will be described with reference to FIGS. In the following description of the operation of the printing apparatus 10, it is assumed that only the skew feeding operation is performed as an example of the initialization operation for easy understanding of the description. 4 to 10, the moving direction of the medium M is expressed by a white arrow.

  Now, as shown in FIG. 4, when printing on the medium M in the printing apparatus 10, the roll body R is set in the feeding unit 20 by the user. Subsequently, the interval between the first drive roller 311 and the first driven roller 312 is a first interval D1 that can sandwich the medium M, and the interval between the second drive roller 321 and the second driven roller 322 is the medium. The second interval D2 is such that M cannot be clamped. Then, the second drive roller 321 is rotated in the first rotation direction R1.

  Thereafter, the medium M is pulled out from the roll body R until the second position P2 is reached in a state where the leading end of the medium M passes between the second driving roller 321 and the second driven roller 322 by the user's work. It is. Then, based on the detection result of the first medium detection unit 34, it is detected that the front end of the medium M has been pulled out to the first position P1, and the second drive roller 321 in the second rotation direction R2 is detected. The rotation is stopped.

  After that, as shown in FIG. 5, the interval between the second driving roller 321 and the second driven roller 322 is set to a first interval D <b> 1 at which the medium M can be sandwiched based on a user operation. Furthermore, driving of the suction fan 44 of the support portion 40 is started, and a force for attracting the medium M to the support base 41 acts through the suction hole 45.

  Subsequently, the first drive roller 311, the second drive roller 321, and the roll body R are rotated in the first rotation direction R <b> 1. As a result, the medium M is fed out from the feeding unit 20 and the medium M is transported by the second transport unit 32. Then, the leading edge of the medium M enters between the first driving roller 311 and the first driven roller 312, and the medium M is positioned so that the leading edge of the medium M is located downstream of the first transport unit 31. Be transported.

  As shown in FIG. 5, when the leading edge of the medium M reaches the third position P3 on the downstream side of the first transport unit 31 and on the upstream side of the reference position P4, the first drive is performed. The rotation of the roller 311, the second drive roller 321, and the roll body R is stopped. Note that whether or not the front end of the medium M is located at the third position P3 may be determined based on the detection result of the second medium detection unit 35. That is, based on the detection result of the second medium detection unit 35, the timing at which the leading edge of the medium M passes the second position P2 is detected, and the amount of feeding of the medium M from the timing is the second position P2. The determination may be made based on whether or not the distance from the first to the third position P3 has been reached.

  Subsequently, in order to eliminate the skew of the medium M, a forward transport operation for transporting the medium M in the transport direction F by a reference transport amount, and a reference of the medium M in the direction opposite to the transport direction F after the forward transport operation. A skew feeding operation (an example of an initialization operation) including a reverse transport operation for transporting only the transport amount is performed. Increasing the reference transport amount tends to increase the effect of eliminating the skew of the medium M, and shortening the reference transport amount shortens the time required for the skew feeding operation. Therefore, it is desirable to obtain an ideal numerical value for the reference transport amount in advance by experiments or the like. The reference transport amount may be changed according to the type of the medium M, such as the material of the medium M, the thickness of the medium M, or the length of the medium M in the width direction X.

  As shown in FIG. 6, in the forward transport operation, when the leading end of the medium M is located downstream of the first transport unit 31, the first transport unit 31 transports the medium M fed out by the feeding unit 20. Therefore, since the medium M can be transported in the transport direction F, it is not necessary to transport the medium M by the second transport unit 32. Therefore, in the present embodiment, when the skew feeding operation is performed, the interval between the second drive roller 321 and the second driven roller 322 is set so that the second transport unit 32 does not transport the medium M. Is the second interval D2 that cannot be clamped. Then, the medium M is transported in the transport direction F by rotating the first drive roller 311, the second drive roller 321, and the roll body R in the first rotation direction R <b> 1.

  By the way, if the rotation of the second drive roller 321 is stopped in the forward transport operation, the medium M transported in the transport direction F and the non-rotating second drive roller 321 are in sliding contact with each other, so that the back surface of the medium M May be damaged. In this regard, in the present embodiment, the second driving roller 321 is rotated in the first rotation direction R1 when the forward conveyance operation is performed, so that the back surface of the medium M is suppressed from being damaged. Thereafter, when the transport amount of the medium M in the transport direction F becomes the reference transport amount, the rotation of the first drive roller 311, the second drive roller 321, and the roll body R is stopped, and the forward transport operation ends.

  Subsequently, as shown in FIG. 7, in the reverse conveyance operation, the interval between the first drive roller 311 and the first driven roller 312 and the interval between the second drive roller 321 and the second driven roller 322 are set to the second value. The first drive roller 311, the second drive roller 321, and the roll body R are rotated in the second rotation direction R <b> 2 with the interval D <b> 2. Thus, in the reverse transport operation, the medium M is transported in the direction opposite to the transport direction F.

  In the reverse transport operation, the portion of the medium M transported downstream from the first transport unit 31 that is supported by the support base 41 is attracted to the support base 41 by the suction force acting on the support base 41. Will be. In other words, the medium M is only adsorbed to the support base 41 without being sandwiched between the first driving roller 311 and the first driven roller 312, and thus is allowed to move in the width direction X. For this reason, when the medium M is skewed, the position of the medium M in the width direction X follows the roll body R supported by the feeding unit 20 as the reverse conveyance operation is performed. M skew is eliminated.

  As shown in FIG. 7, when the transport amount of the medium M in the direction opposite to the transport direction F becomes the reference transport amount, the first drive roller 311, the second drive roller 321, and the roll body R are rotated. The reverse conveyance operation (skew taking operation) is completed. Note that, in the state where the reverse transport operation is completed, the leading edge of the medium M is located at the third position P3.

  Further, as shown in FIG. 7, during the reverse conveyance operation, the distance between the first driving roller 311 and the first driven roller 312, and the second driving roller 321 and the second driven roller 322. Although the interval is the second interval D2 where the medium M cannot be clamped, the first drive roller 311 and the second drive roller 321 are rotated. For this reason, it is suppressed that the back surface of the medium M is damaged similarly to the case where the forward transport operation is performed.

  As shown in FIG. 8, in the initial transport operation that is performed after the skew feeding operation is finished, the interval between the first drive roller 311 and the first driven roller 312 is the first interval D1 that can sandwich the medium M. The interval between the second drive roller 321 and the second driven roller 322 is set to a second interval D2 at which the medium M cannot be sandwiched. In order to transport the medium M in the transport direction F, the first drive roller 311, the second drive roller 321, and the roll body R are rotated in the first rotation direction R <b> 1.

  Further, in the initial transport operation, the tension acting on the medium M transported between the first transport unit 31 and the feeding unit 20 is controlled by controlling the rotation amounts of the first drive roller 311 and the roll body R. Increased. Here, when the length of the medium M transported downstream from the first transport unit 31 is short, that is, the length from the first transport unit 31 holding the medium M to the leading end of the medium M is short. When the length is short, the leading edge of the medium M is easy to move, and wrinkles are likely to occur in the medium M that is transported downstream from the first transport unit 31. In this regard, in the initial transport operation, the tension acting on the medium M transported between the first transport unit 31 and the feeding unit 20 is increased, so that the transport is performed downstream of the first transport unit 31. Generation of wrinkles on the medium M is suppressed.

Also, when the initial transport operation is performed, the second drive roller 321 is rotated as in the case of performing the forward transport operation, so that the back surface of the medium M is suppressed from being damaged.
Then, as shown in FIG. 8, when the leading end of the medium M reaches the reference position P4 on the downstream side of the third position P3, the rotation of the first driving roller 311, the second driving roller 321 and the roll body R is performed. Is stopped, and the initial transfer operation is completed.

Subsequently, as illustrated in FIG. 9, a printing operation is performed in which a unit transport operation for transporting the medium M by a unit transport amount and an ejection operation for ejecting ink toward the medium M are repeated.
In the unit transport operation, the interval between the first driving roller 311 and the first driven roller 312 and the interval between the second driving roller 321 and the second driven roller 322 are set as the first interval D1 at which the medium M can be sandwiched. The first drive roller 311, the second drive roller 321 and the roll body R are rotated in the first rotation direction R1.

  Further, in the unit transport operation (printing operation), the rotation amounts of the first drive roller 311 and the second drive roller 321 are controlled, so that the first transport unit 31 and the second transport unit 32 are controlled. A slack is formed in the conveyed medium M. As a result, the tension does not substantially act on the medium M transported between the first transport unit 31 and the second transport unit 32. In other words, when performing the unit transport operation (printing operation), the tension acting on the medium M transported between the first transport unit 31 and the second transport unit 32 is determined when performing the initial transport operation. It becomes smaller than the tension acting on the medium M transported between the first transport unit 31 and the feeding unit 20.

  Thereby, the variation in the transport amount of the medium M in the width direction X is suppressed by the variation in the width direction X of the tension acting on the medium M transported between the first transport unit 31 and the second transport unit 32. When the unit transport operation is performed, a decrease in the transport accuracy of the medium M is suppressed.

  Further, when performing the unit transport operation, the rotation amount of the second drive roller 321 and the roll body R is controlled, so that the medium M transported between the second transport unit 32 and the feeding unit 20 is controlled. The acting tension is increased. That is, when the unit transport operation (printing operation) is performed, the tension acting on the medium M transported between the second transport unit 32 and the feeding unit 20 is the first transport unit 31 and the second transport. It becomes larger than the tension acting on the medium M conveyed between the sections 32.

  For this reason, since tension acts on the medium M conveyed between the second conveyance unit 32 and the feeding unit 20, the medium M is unintentionally unwound by its own weight from the roll body R supported by the feeding unit 20. It is suppressed. As a result, the conveyance failure of the medium M between the second conveyance unit 32 and the feeding unit 20 is suppressed.

  Further, when performing a printing operation, the length of the medium M transported downstream from the first transport unit 31 is long, and the leading end of the medium M is difficult to move. Therefore, unlike the case of performing the initial transport operation, the first transport unit 31 transports even if the tension acting on the medium M transported between the first transport unit 31 and the feeding unit 20 is reduced. Generation of wrinkles in the medium portion is suppressed.

  When the transport amount of the medium M reaches the unit transport amount, the rotation of the first drive roller 311, the second drive roller 321, and the roll body R is stopped, and the unit transport operation ends. Subsequently, while the carriage 53 is moved in the width direction X, an ejection operation for ejecting ink from the ejection unit 51 toward the medium M is performed, and printing for one pass is performed. Then, the printing operation is performed by alternately repeating the unit conveyance operation and the discharge operation.

  As shown in FIG. 10, when the printing operation is finished, the interval between the first driving roller 311 and the first driven roller 312 is set to the first interval D1, and the second driving roller 321 and the second driven roller 322 are set. The first drive roller 311, the second drive roller 321, and the roll body R are rotated in the first rotation direction R <b> 1 in a state in which the interval is set to the second interval D <b> 2. In this way, the medium M is transported so that the printed area of the medium M is located downstream of the cutting position P5.

  Subsequently, when the printed area of the medium M is positioned downstream of the cutting position P5, the rotation of the first driving roller 311, the second driving roller 321 and the roll body R is stopped, and the cutting unit 60 is driven. . As a result, a cut medium M1 is generated from the medium M as shown in FIG. When the next printing is performed after cutting the medium M, the medium M is transported so that the leading edge of the medium M is positioned at the third position P3 in the same manner as the reverse transport operation, and then the initial transport is performed. Perform the print operation. For this reason, even when the next printing is performed after the medium M is cut, it is possible to suppress the printing on the wrinkled medium M in terms of the initial carrying operation, and the printing accuracy is lowered. Is suppressed.

According to the above embodiment, the following effects can be obtained.
(1) When performing the printing operation (unit transport operation), the tension acting on the medium M transported between the first transport unit 31 and the feeding unit 20 is made smaller than when performing the initial transport operation. .

  For this reason, when the initial transport operation is performed, the tension acting on the medium M transported between the first transport unit 31 and the feeding unit 20 becomes relatively large. Therefore, even when the medium M is transported in a state where the length in the transport direction F of the medium M located on the downstream side of the first transport unit 31 is short, the medium transported by the first transport unit 31 The occurrence of wrinkles in M is suppressed.

  On the other hand, when the printing operation (unit transport operation) is performed, the tension acting on the medium M transported between the first transport unit 31 and the feeding unit 20 is relatively small. For this reason, the variation in the width direction X of the conveyance amount of the medium M based on the variation in the width direction X of the tension acting on the medium M conveyed between the first conveyance unit 31 and the feeding unit 20 is suppressed. The skew of the medium M transported by one transport unit 31 is suppressed.

  Thus, when the initial transport operation is performed, the generation of wrinkles is suppressed, so that it is possible to suppress the print quality from being deteriorated due to the wrinkles generated on the medium M before the start of the printing operation. In addition, when performing a printing operation, it is possible to suppress the skew of the medium M accompanying the conveyance of the medium M, and it is possible to suppress a decrease in print quality due to the skew of the medium M. Therefore, when printing is performed on the medium M unrolled from the roll body R, it is possible to suppress a decrease in print quality.

  (2) When performing the printing operation (initial transport operation), the tension acting on the medium M transported between the second transport unit 32 and the feeding unit 20 is applied to the first transport unit 31 and the second transport unit 20. The tension is larger than the tension acting on the medium M transported between the transport sections 32.

  Thereby, when performing a printing operation, the tension acting on the medium M transported between the first transport unit 31 and the second transport unit 32 becomes relatively small, so the medium M transported by the transport unit 30 Can be prevented from skewing. Further, when performing a printing operation, the tension acting on the medium M transported between the second transport unit 32 and the feeding unit 20 becomes relatively large, so the medium M wound around the roll body R is not intended. It is possible to suppress unwinding by its own weight.

  (3) When performing the initial transport operation, the interval between the second driving roller 321 and the second driven roller 322 is set to a second interval D2 at which the medium M cannot be sandwiched. For this reason, when the initial transport operation is performed, when tension is applied to the medium M transported between the first transport unit 31 and the feeding unit 20, the transport amount of the medium M of the first transport unit 31 and It is only necessary to control the feeding amount of the medium M of the feeding unit 20. Therefore, when the initial transport operation is performed, the control configuration can be simplified because the transport amount of the medium M of the second transport unit 32 need not be controlled.

  (4) A forward transport operation that unwinds the medium M and transports the medium M in the transport direction F by a reference transport amount, and a reverse operation that winds up the medium M and transports the medium M by a reference transport amount in a direction opposite to the transport direction F. By performing the skew feeding operation including the transport operation, the skew of the medium M can be eliminated. As a result, it is possible to prevent the initial transport operation and the printing operation from being started while the medium M is skewed.

  Further, when the skew feeding operation is performed, the interval between the second driving roller 321 and the second driven roller 322 becomes the second interval D2 in which the medium M cannot be sandwiched, so that the medium of the second transport unit 32 Since it is not necessary to control the transport amount of M, the control configuration can be simplified.

  (5) When performing the printing operation, the medium M transported between the first transport unit 31 and the second transport unit 32 is slackened so that the tension does not substantially act on the medium M. For this reason, when performing a printing operation, the variation in the conveyance amount of the medium M in the width direction X based on the variation in the width direction X of the tension acting on the medium M is suppressed, and the skew of the medium M is further suppressed. Can do.

In addition, you may change the said embodiment as shown below.
In the above embodiment, only the skew feeding operation is performed as the initialization operation. However, at least one of the following detection estimation operations may be performed as the initialization operation. In this case, the skew feeding operation may or may not be performed. Incidentally, the initialization operation is an operation performed in association with the conveyance of the medium M in at least one of the conveyance direction F and the opposite direction.

As the detection estimation operation, an operation for estimating the remaining amount of the medium M wound around the roll body R set in the feeding unit 20 (hereinafter also referred to as “remaining amount estimation operation”) may be performed. .
In the remaining amount estimation operation, the interval between the first drive roller 311 and the first driven roller 312 is set as the first interval D1 that can sandwich the medium M, and the interval between the second drive roller 321 and the second driven roller 322 is set. Is set to the second interval D2 in which the medium M cannot be clamped, and the leading end of the medium M is located downstream of the third position P3.

  Then, the first driving roller 311, the second driving roller 321, and the roll body R are moved in the first rotation direction R <b> 1 so that tension is applied to the medium M between the first transport unit 31 and the feeding unit 20. The medium M is rotated and conveyed in the conveyance direction F by a predetermined amount. Subsequently, the conveyance amount (predetermined amount) of the medium M calculated based on the rotation amount of the first drive roller 311 is divided by the rotation number of the roll body R required to feed the medium M by the conveyance amount. Thus, the feed amount per rotation of the roll body R, in other words, the outer periphery of the roll body R is calculated. Based on the outer circumference of the roll body R thus calculated, the outer diameter of the roll body R is estimated, and the remaining amount of the medium M having a correlation with the outer diameter is estimated.

  Note that the remaining amount estimation operation may not be calculated based on the transport amount of the medium M and the rotation speed of the roll body R as described above. For example, at the end of the previous printing, the remaining amount of the medium M is printed as a barcode on the medium M, and at the next printing start, the barcode is read by a barcode reading unit (for example, the third medium detection unit 52). Thus, the remaining amount may be estimated.

As the detection estimation operation, an operation for estimating the length of the medium M in the width direction X (hereinafter also referred to as “width detection operation”) may be performed.
The width detection operation is performed in a state where the medium M is transported in the transport direction F so that the leading end of the medium M is positioned downstream of the third medium detection unit 52 supported by the carriage 53. Then, while moving the carriage 53 in the width direction X, the third medium detection unit 52 is irradiated with light toward the support base 41 or the medium M supported by the support base 41 and the reflected light is received. The intensity distribution of reflected light in the width direction X is acquired. Subsequently, the width of the medium M is estimated based on the intensity distribution. As an example, when the reflectivity of the surface of the support base 41 is low and the reflectivity of the surface of the medium M is high, of the reflected light intensity distribution, the portion of the reflected light that is sandwiched between the portions where the reflected light is low. The length is the width of the medium M.

  As the detection estimation operation, the feeding unit 20 may perform an operation of detecting a load applied to the feeding motor 22 when the roll body R is rotated (hereinafter also referred to as “load detection operation”).

  The load detection operation is performed, for example, during the forward conveyance operation of the skew feeding operation. That is, the load detection operation is performed by measuring a load applied to the feeding motor 22 when the roll body R is rotated in a state where no tension is applied to the medium M. The load applied to the feeding motor 22 may be detected based on electrical characteristics such as the current value of the feeding motor 22 when the roll body R is rotated, or a torque detector is provided on the roll body R. Then, it may be detected based on the detection result of the torque detector.

  Further, the load detected by the detection estimation operation is used when adjusting the magnitude of tension acting on the medium M conveyed between the first conveyance unit 31 and the feeding unit 20 when performing the initial conveyance operation. Is done. That is, in this case, the first transport motor is set so as to be a load for applying the target tension to the medium M with reference to the load of the feeding motor 22 when no tension is applied to the medium M. The amount of rotation of the motor 313 and the feeding motor 22 is controlled.

  If it can be determined that the medium M is not skewed, the skew feeding operation may not be performed. Whether or not the medium M is skewed may be determined based on, for example, a difference in detection results of the third medium detection unit 52 when the leading end position of the medium M is different. That is, after the position of one end of the medium M is detected by the third medium detection unit 52 while the medium M is supported on the support base 41, one end of the medium M is transported in the transport direction F. The position of the part is detected. Then, if the positional deviation amount at one end of the medium M is less than the allowable amount before and after the conveyance, it is determined that the skew is not performed. You can determine that you are doing.

  When performing the unit transport operation of the printing operation, tension may be applied to the medium M transported between the first transport unit 31 and the second transport unit 32. However, when performing the unit transport operation, the tension acting on the medium M transported between the first transport unit 31 and the second transport unit 32 is between the second transport unit 32 and the feeding unit 20. It is assumed that the tension is smaller than the tension acting on the conveyed medium M. Further, the tension is smaller than the tension acting on the medium M transported between the first transport unit 31 and the feeding unit 20 when performing the initial transport operation.

  When performing the reverse conveyance operation of the skew feeding operation, the interval between the first drive roller 311 and the first driven roller 312 may be the first interval D1. In this case, when the reverse transport operation is performed, it is desirable that the force with which the first driven roller 312 presses the medium M toward the first drive roller 311 is smaller than when the forward transport operation is performed. .

  Before the reverse feeding operation of the skew feeding operation is completed, for example, the first driving roller 311 and the first driven member are moved from the leading edge of the medium M to the third position P3 after reaching the reference position P4. The interval between the rollers 312 may be the first interval D1 at which the medium M can be held. In this case, tension may be applied to the medium M transported in the direction opposite to the transport direction F between the first transport unit 31 and the feeding unit 20. In this case, the magnitude of the tension acting on the medium M is smaller than the tension acting on the medium M in the initial transport operation, and the first transport unit 31 and the second transport in the printing operation (reference transport operation). It is desirable that the tension is greater than the tension acting on the medium M conveyed between the sections 32.

  When performing the initial conveying operation, the interval between the second driving roller 321 and the second driven roller 322 may be set as the first interval D1. In this case, the tension acting on the medium M transported between the first transport unit 31 and the second transport unit 32, and the medium M transported between the second transport unit 32 and the feeding unit 20. It is desirable that the amount of rotation of the first drive roller 311, the second drive roller 321, and the roll body R is controlled so that the tension to be applied becomes equal.

  The printing apparatus 10 may not include the second transport unit 32. In this case, when the printing operation is performed, the feeding unit is configured so that the tension acting on the medium M transported between the first transport unit 31 and the feeding unit 20 is smaller than when the initial transport operation is performed. It is desirable to control the transport amount of the twenty mediums M and the feed amount of the medium M of the feeding unit 20.

The printing apparatus 10 may not include the cutting unit 60. In this case, the printing apparatus 10 preferably includes a winding unit that winds the printed medium M.
The support unit 40 may not include a mechanism for adsorbing the medium M on the support base 41.

  The feeding unit 20 may not hold the roll body R. In this case, it is desirable to provide a holding device that holds the roll body R so as to be rotatable separately from the printing apparatus 10. In this case, the feeding unit 20 may feed the medium M by indirectly rotating the roll body R held by the holding device by applying a force in the transport direction F to the medium M. The medium M may be fed out by directly rotating the roll body R held by the holding device.

The feeding unit 20 may not be able to wind up the medium M.
-In the 1st conveyance part 31, the 1st adjustment part 314 moves the 1st driving roller 311 with respect to the 1st driven roller 312, and the 1st driving roller 311 and the 1st driven roller The interval 312 may be adjusted. The same applies to the second transport unit 32.

  In the first transport unit 31, the first drive roller 311 may be a transport belt that imparts transport force to the medium M by rotating in contact with the back surface of the medium M. The same applies to the second transport unit 32.

  The printing unit 50 may be changed to a so-called line head printer that does not include the carriage 53 but includes a long fixed print head (line head) corresponding to the entire width of the medium M. In this case, the discharge head may be arranged so that the printing range covers the entire width of the medium M by arranging a plurality of unit head portions in which the nozzles are formed in parallel, or the medium M is formed on a single long head. The printing range may extend over the entire width of the medium M by arranging a large number of nozzles over the entire width.

  Recording materials used for printing include fluids other than ink (liquids, liquids in which particles of functional materials are dispersed or mixed, liquids such as gels, and solids that can be jetted as fluids. ). For example, recording is performed by ejecting a liquid material in which a material such as an electrode material or a color material (pixel material) used for manufacturing a liquid crystal display, an EL (electroluminescence) display, and a surface emitting display is dispersed or dissolved. It may be configured.

  Further, the printing apparatus 10 includes a fluid ejecting apparatus that ejects a fluid such as a gel (for example, a physical gel), and a powder ejecting apparatus that ejects a solid such as toner (powder). (For example, a toner jet recording apparatus) may be used. In the present specification, the term “fluid” is a concept that does not include a fluid consisting only of gas. Examples of the fluid include liquid (inorganic solvent, organic solvent, solution, liquid resin, liquid metal (metal melt), etc. ), Liquids, fluids, powders (including granules and powders), and the like.

  As long as the printing apparatus 10 is a printer that heats the medium M, the printing apparatus 10 is not limited to a printer that performs recording by ejecting a fluid such as ink. For example, a laser printer, an LED printer, a thermal transfer printer (including a sublimation printer), and the like Non-impact printers, or impact printers such as dot impact printers may be used.

  The medium M is not limited to paper, but may be a fabric used for a plastic film, a textile printing apparatus, or the like. Further, the length of the medium M in the axial direction is not necessarily equal to that of the roll body R. For example, a chain, tape, ribbon, string, thread, or the like having a shorter length in the axial direction than the roll body R can be used in the axial direction. The roll body R may be formed by winding while shifting the position.

  DESCRIPTION OF SYMBOLS 10 ... Printing device, 20 ... Feeding part, 21 ... Holding | maintenance part, 22 ... Feeding motor, 30 ... Conveyance part, 31 ... 1st conveyance part, 311 ... 1st drive roller, 312 ... 1st driven roller, 313 ... 1st conveyance motor, 314 ... 1st adjustment part, 32 ... 2nd conveyance part, 321 ... 2nd drive roller, 322 ... 2nd driven roller, 323 ... 2nd conveyance motor, 324 ... 1st 2 adjustment units, 33 ... relay unit, 331 ... first relay roller, 332 ... second relay roller, 34 ... first medium detection unit, 35 ... second medium detection unit, 40 ... support unit, 41 DESCRIPTION OF SYMBOLS ... Support stand, 42 ... Gas chamber, 43 ... Negative pressure chamber, 44 ... Suction fan, 45 ... Suction hole, 50 ... Printing part, 51 ... Ejection part, 52 ... Third medium detection part, 53 ... Carriage, 54 ... Guide shaft 55 ... carriage motor 60 ... cutting section 70 Control unit, D1 ... first interval, D2 ... second interval, F ... transport direction, M ... medium, M1 ... medium, P1 ... first position, P2 ... second position, P3 ... third position , P4 ... reference position, P5 ... cutting position, R ... roll body, R1 ... first rotation direction, R2 ... second rotation direction, X ... width direction.

Claims (5)

A feeding unit for feeding out the medium by rotating a roll body on which the medium is wound;
A transport unit for transporting the medium fed by the feed unit in the transport direction;
A printing unit that performs printing on the medium conveyed by the conveyance unit;
A control unit for controlling a transport amount of the medium of the transport unit and a feed amount of the medium of the feeding unit to adjust a tension acting on the medium transported between the transport unit and the feeding unit; With
The controller is
A printing operation for performing printing on the conveyed medium is performed after an initial conveying operation for conveying the medium so that the leading edge of the medium is positioned at a reference position downstream of the conveying unit in the conveying direction. And
When the printing operation is performed, a tension acting on the medium conveyed between the conveyance unit and the feeding unit is made smaller than when the initial conveyance operation is performed. . When the transport unit is a first transport unit, the medium is provided between the first transport unit and the feeding unit, and transports the medium fed from the feeding unit toward the first transport unit. A second transport unit;
The control unit controls the first conveyance unit by controlling a conveyance amount of the medium of the first conveyance unit, a conveyance amount of the medium of the second conveyance unit, and a feeding amount of the medium of the feeding unit. Part, adjusting the tension acting on the medium conveyed between the second conveying part and the feeding part,
When performing the printing operation, the tension acting on the medium conveyed between the second conveyance unit and the feeding unit is set between the first conveyance unit and the second conveyance unit. The printing apparatus according to claim 1, wherein the tension is greater than a tension acting on the conveyed medium. The second transport unit includes a second drive roller that imparts a transport force to the medium, a second driven roller that sandwiches the medium together with the second drive roller, the second drive roller, and the second drive roller. A second adjusting unit that adjusts the distance between the second driven rollers,
When the second driving roller and the second driven roller sandwich the medium as the first interval, and the second driving roller and the second driven roller do not sandwich the medium When the interval is the second interval,
When performing the printing operation, the control unit causes the interval in the second conveyance unit to be the first interval, and when performing the initial conveyance operation, the control unit performs the second conveyance. The printing apparatus according to claim 2, wherein the interval in the section is the second interval. The feeding unit is capable of winding the medium by rotating the roll body in the reverse direction to the feeding of the medium,
The control unit includes a forward transport operation for transporting the medium in the transport direction along with the feeding of the medium by the feeding unit and a winding of the medium by the feeding unit before the initial transport operation. A skew feeding operation including a reverse transport operation for transporting the medium in a direction opposite to the transport direction;
The printing apparatus according to claim 3, wherein when the skew feeding operation is performed, the interval in the second transport unit is set as the second interval. The said control part loosens the said medium conveyed between the said 1st conveyance part and the said 2nd conveyance part, when making the said printing operation. The Claims 2-4 The printing apparatus as described in any one of these.