Printing apparatus, tension adjustment method, and conveying apparatus

Abstract

To improve the transport of media in a printing apparatus. [Solution] The printing apparatus 10 comprises a print head 12, a transport unit 16, a rotary drive unit 202, a tension application unit 204, a state detection unit 206, and a control unit 30. The tension application unit 204 has a tension bar 212 and a bar holding unit 214. The state detection unit 206 detects the position of the tension bar 212 in its movement path. The control unit 30 detects the movement time required for the tension bar 212 to move from a preset first position to a second position based on the position of the tension bar 212 detected by the state detection unit 206, and changes the core rotation speed at which the rotary drive unit 202 rotates the core 150 based on the above movement time.

Description

Technical Field

[0001] The present invention relates to a printing apparatus, a tension adjustment method, and a conveyance apparatus.

Background Art

[0002] Conventionally, printing apparatuses such as inkjet printers have been widely used. Regarding the configuration of a printing apparatus, a configuration including a printing mechanism that performs printing on a long medium is known (see, for example, Patent Document 1).

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] In a printing apparatus, when a long medium is used, for example, a medium wound in a roll shape is sequentially fed out to perform printing, and the medium on which printing has been completed is sequentially wound up. In this case, if there is a difference between the conveyance speed at which the medium is conveyed at the position of the print head and the moving speed of the medium on the feeding side or the winding side of the medium, for example, a problem such as sagging of the medium caused by gravity occurs. Therefore, in this case, for example, a tension bar serving as a weight is brought into contact with the medium to apply tension to the medium and eliminate the sagging. Further, in this case, for example, a multi-stage sensor (such as a pseudo encoder) that detects the depth of sag of the medium is used to detect that sag has occurred in the medium, and the feeding and winding speeds of the medium are controlled according to the detection result. With this configuration, for example, by performing feeding and winding of the medium in a configuration asynchronous with the operation of the conveyance unit that conveys the medium at the position of the print head, the medium can be appropriately conveyed with a simple configuration.

[0005] However, in such a configuration, if the media is transported continuously, for example, the amount of media fed out or rewound in the transport unit may not keep up with the amount of media transported in the transport unit, making it impossible to use the tension bar properly. More specifically, for example, if the media is transported intermittently in the transport unit, as in normal printing, there is sufficient time for the amount of media fed out or rewound in the transport unit to keep up with the amount of media being fed. Therefore, in such cases, even when transporting the media with the above configuration, the media can usually be transported while the tension bar is in contact with the media at the appropriate position.

[0006] In contrast, when transporting media suddenly and continuously according to user instructions, for example, it may not be possible to secure sufficient time for the amount of media fed out and wound up in the transport section to keep up with the amount of media being transported. As a result, for example, the tension bar may spring up on the media feeding side, or the tension may become too loose on the winding side. Therefore, when transporting media using the above method, for example, the transport operation may become unstable. Thus, the present invention aims to provide a printing apparatus, a tension adjustment method, and a transport apparatus that can solve the above problems. [Means for solving the problem]

[0007] The inventors of this invention have diligently researched methods for more appropriately transporting a medium under various conditions. They considered detecting the travel time of a tension bar as it moves within a predetermined range and changing the speed of unwinding and winding the medium based on this travel time. Through various experiments, they found that this method allows for more appropriate transport of the medium, even in situations where the medium is transported suddenly and continuously. Furthermore, through further diligent research, the inventors of this invention identified the features necessary to achieve this effect, leading to the present invention.

[0008] To solve the above problems, the present invention provides a printing apparatus for printing on a medium, comprising: a print head for attaching colorant to the medium; a transport unit for transporting the medium in a predetermined transport direction such that the medium passes a position opposite the print head; a rotation drive unit for rotating a core around which the medium is wound at a position upstream or downstream of the transport unit in the transport path on which the medium is transported; a tension applying unit for applying tension to the medium between the medium roll around which the medium is wound and the transport unit; a state detection unit for detecting the state of the tension applying unit; and a control unit for controlling the operation of the rotation drive unit, wherein the tension applying unit is The device comprises a tension bar, which is a rod-shaped member that contacts the medium with its longitudinal direction parallel to the axial direction, and a bar holding part that holds the tension bar so as to be movable along a predetermined movement path. The state detection unit detects the position of the tension bar in the movement path, and the control unit detects the movement time, which is the time required for the tension bar to move from a preset first position to a second position different from the first position in the movement path, based on the position of the tension bar detected by the state detection unit, and changes the winding core rotation speed, which is the rotation speed at which the rotation drive unit rotates the winding core, based on the movement time.

[0009] With this configuration, for example, the core rotation speed can be appropriately changed to match the actual movement of the tension bar during media transport by changing the core rotation speed based on the travel time of the tension bar moving between the first and second positions. Furthermore, this allows for appropriate stabilization of the media transport operation under various conditions, such as when transporting media suddenly and continuously. Therefore, with this configuration, media transport can be performed more appropriately in a printing apparatus, for example.

[0010] In this configuration, the printing apparatus further includes, for example, a main scanning drive unit that causes the print head to perform a main scanning operation, moving the print head in a main scanning direction perpendicular to the media transport direction at the transport unit's position, and an operation reception unit that receives instructions from the user to feed the media. In this case, during printing to attach colorants to the media, the transport unit, for example, stops feeding the media while the main scanning operation is being performed and feeds the media in between the main scanning operations. As a result, during printing, the transport unit transports the media intermittently. In this case, for example, at times other than printing, the control unit causes the transport unit to transport the media based on instructions received from the user by the operation reception unit. In this case, for example, the control unit makes the control it performs on the core rotation speed differently during instruction transport and during printing. More specifically, during instruction transport, for example, the control unit detects the travel time and changes the core rotation speed based on the travel time. In this case, the operation of the control unit during instruction transport can be considered as controlling the operation of the rotation drive unit based on the travel time. Furthermore, in this case, during printing, the control unit controls the operation of the rotary drive unit, for example, without relying on travel time. With this configuration, for example, during printing, the transport of the media can be appropriately controlled with simpler control. Also, during instructed transport, for example, by controlling the operation of the rotary drive unit based on travel time, the transport of the media can be controlled more appropriately, even when transporting media continuously.

[0011] Furthermore, in this configuration, if the direction in which the transport unit rotates the core in accordance with the direction in which the medium is fed is defined as the forward direction, then in the forward rotation direction around the core's axis, the second position is a position upstream of the first position. Then, during printing and instruction transport, when the tension bar moves from the second position to the first position, the control unit rotates the core in the forward direction to move the tension bar toward the second position. With this configuration, for example, the direction of movement of the tension bar can be appropriately reversed for a tension bar that has reached the first position. Also, during printing, when the tension bar moves from the first position to the second position, the control unit moves the tension bar toward the first position, for example, by stopping the rotation of the core in the rotation drive unit. With this configuration, for example, during printing, the direction of movement of the tension bar that has reached the second position can be appropriately reversed with simple control. In contrast, when the tension bar moves from the first position to the second position during instruction transport, the control unit, for example, causes the rotation drive unit to rotate the core at the rotational speed at which the tension bar moves toward the first position, without stopping the rotation of the core. With this configuration, for example, when transporting the medium continuously during instruction transport, the direction of movement of the tension bar can be appropriately reversed for the tension bar that has reached the second position.

[0012] Furthermore, if the speed at which the medium moves at the position of the transport unit is defined as the transport speed, and the speed at which the medium moves at the outermost position of the medium wound on the core in accordance with the rotation of the core is defined as the roll position speed, then during printing, when the tension bar moves from the second position to the first position, the control unit moves the tension bar toward the second position by, for example, rotating the core in the rotation drive unit so that the roll position speed is faster than the transport speed. With this configuration, for example, during printing, the direction of movement of the tension bar that has reached the first position can be appropriately reversed with simple control. Also, during instruction transport, when the tension bar moves from the second position to the first position, the control unit moves the tension bar toward the second position by, for example, rotating the core at a rotation speed determined based on the movement time detected when the tension bar immediately reached the second position. With this configuration, for example, even during instruction transport, the direction of movement of the tension bar that has reached the first position can be appropriately reversed. Furthermore, in this case, by rotating the core at a rotational speed determined based on the travel time, the core rotational speed can be appropriately changed to match the actual movement that occurs in the tension bar during medium transport. Therefore, with this configuration, medium transport can be performed more appropriately, for example, when continuously transporting medium during instructed transport.

[0013] In this configuration, the range between the first position and the second position in the movement path can be considered, for example, as a target range for the position of the tension bar. When the tension bar moves outside the target range, the control unit changes the core rotation speed, for example, in the direction that brings the tension bar back into the target range. With this configuration, for example, the position of the tension bar can be appropriately controlled to match the target range. Also, for example, during instructed transport, when the tension bar moves outside the target range from the side of the first position, the control unit changes the core rotation speed based, for example, the movement time detected at the moment the tension bar reached the second position immediately before. With this configuration, for example, the core rotation speed can be appropriately controlled based on the movement time.

[0014] In this configuration, the transport unit transports the medium at a constant transport speed. The rotation drive unit rotates, for example, the winding core on the winding side and the winding core on the unwinding side. In this case, the winding core on the winding side can be considered, for example, a winding core that winds the medium downstream of the transport unit in the transport path. The winding core on the unwinding side can be considered, for example, a winding core that unwinds the medium upstream of the transport unit in the transport path. In these cases, when the tension bar moves outside the target range from the first position, the control unit increases the winding core rotation speed so that the roll position speed becomes faster than the transport speed. When the tension bar moves outside the target range from the second position, the control unit decreases the winding core rotation speed so that the roll position speed becomes slower than the transport speed. With this configuration, for example, on both the winding and unwinding sides, the winding core rotation speed can be appropriately changed to the speed at which the tension bar returns to the target range when the tension bar reaches the edge of the target range. Furthermore, as an example of the present invention, we can also consider configurations for tension adjustment methods and conveying devices having the same characteristics as described above. In these cases as well, for example, the same effects as described above can be obtained. [Effects of the Invention]

[0015] According to the present invention, for example, the transport of the medium can be performed more appropriately in a printing apparatus. [Brief explanation of the drawing]

[0016] [Figure 1] This figure illustrates a printing apparatus 10 according to one embodiment of the present invention. Figure 1(a) shows an example of the configuration of the main parts of the printing apparatus 10. Figure 1(b) is a diagram that further explains the features of the winding section 22 and the feeding section 24 in the printing apparatus 10. [Figure 2] This flowchart shows a simplified example of the control performed by the control unit 30 on the rotary drive unit 202 during printing. [Figure 3] This flowchart shows a simplified example of the control performed by the control unit 30 on the rotary drive unit 202 during instructed transport. [Figure 4] This flowchart simplifies an example of the control performed by the control unit 30 during instruction transport, focusing on the overall operation of the printing device 10. [Figure 5] This diagram illustrates the multiple states that are distinguished according to the position of the tension bar 212 during instruction transport. [Figure 6] This table shows an example of the control performed by the control unit 30 during instructed transport. [Modes for carrying out the invention]

[0017] Hereinafter, embodiments according to the present invention will be described with reference to the drawings. FIG. 1 is a diagram explaining a printing apparatus 10 according to an embodiment of the present invention. FIG. 1(a) shows an example of the configuration of a main part of the printing apparatus 10. FIG. 1(b) is a diagram explaining the features of a winding unit 22 and a feeding unit 24 in the printing apparatus 10 in further detail. Except for the points described below, the printing apparatus 10 and each part of the printing apparatus 10 may have the same or similar features as known printing apparatuses and their respective parts. Further, the printing apparatus 10 may further have, for example, the same or similar configuration as known printing apparatuses in addition to the illustrated configuration. In this example, the printing apparatus 10 is a roll-to-roll type inkjet printer that performs printing on a medium 50 to be printed, and includes a print head 12, a platen 14, a conveyance unit 16, a main scanning driving unit 18, an operation reception unit 20, a winding unit 22, a feeding unit 24, and a control unit 30. The fact that the printing apparatus 10 is of a roll-to-roll type can be understood as, for example, feeding out the medium 50 wound in a roll shape to perform printing, and winding the printed medium 50 into a roll shape.

[0018] Further, among these configurations, the print head 12 is a component for adhering printing color material to the medium 50. In this example, the print head 12 is an inkjet head that ejects ink, which is a color material, by an inkjet method, and adheres ink to the medium 50 by ejecting ink in accordance with instructions from the control unit 30. Further, the printing apparatus 10 may include a plurality of print heads 12. In this case, the plurality of print heads 12 eject inks of different colors from each other, for example. The platen 14 is a table-shaped member that holds the medium 50 at a position facing the print head 12. In this example, the platen 14 is disposed at a position facing the print head 12 between the winding unit 22 and the feeding unit 24, and holds the medium 50 fed by the conveyance unit 16 on its upper surface. The fact that the platen 14 holds the medium 50 on its upper surface can be understood as, for example, holding a portion of the medium 50 that is located on the platen 14.

[0019] The transport unit 16 is configured to transport the medium 50 in a predetermined transport direction so that the medium 50 passes a position opposite the print head 12. In this example, the transport unit 16 has a drive roller 102, an opposing roller 104, a transport drive unit 106, and a driven roller 108. The drive roller 102 is a roller that rotates in accordance with the driving force it receives from the transport drive unit 106, and transports the medium 50 that is fed out from the feed unit 24 toward the winding unit 22 between the winding unit 22 and the feed unit 24. In this example, the drive roller 102 is also positioned between the platen 14 and the feed unit 24. The opposing roller 104 is a roller that sandwiches the medium 50 between itself and the drive roller 102, and rotates together with the drive roller 102 in accordance with the rotation of the drive roller 102. The transport drive unit 106 is a drive unit that rotates the drive roller 102 in accordance with the instructions of the control unit 30. In this example, the transport drive unit 106 has a motor that rotates the drive roller 102, and rotates the drive roller 102 so that the moving speed of the medium 50 at the position of the transport unit 16 becomes a preset constant transport speed. In this way, the transport drive unit 106 causes the transport unit 16 to transport the medium 50 at a constant transport speed, as shown as speed V1 in the figure. The transport speed of the medium 50 at the position of the transport unit 16 can be considered, for example, the speed of the medium 50 at the position where the drive roller 102 contacts the medium 50. To ensure that the transport speed is constant, for example, the operation of the transport drive unit 106 can be controlled by the control unit 30 to make the transport speed substantially constant according to the accuracy required for transport. The driven roller 108 is a roller for adjusting the transport path of the medium 50. In this example, the driven roller 108 is disposed, for example, between the platen 14 and the winding unit 22. The transport unit 16 may have further driven rollers 108 at other positions, for example.

[0020] Also, in the present example, when performing a sub-scanning operation or when receiving a user instruction at the operation reception unit 20, the conveyance unit 16 rotates the drive roller 102 to convey the medium 50. In this case, the sub-scanning operation can be considered, for example, as an operation of moving the print head 12 in a predetermined sub-scanning direction relative to the medium 50. In the present example, the sub-scanning direction is a direction parallel to the conveyance direction of the medium 50 at the position of the conveyance unit 16. Also, during printing for applying ink to the medium 50, the conveyance unit 16 rotates the drive roller 102 between main scanning operations to feed the medium 50, thereby causing the print head 12 to perform the sub-scanning operation. In this case, the main scanning operation can be considered, for example, as an operation of moving the print head 12 in the main scanning direction orthogonal to the sub-scanning direction.

[0021] The main scanning drive unit 18 is a drive unit that causes the print head 12 to perform a main scanning operation. During the main scanning operation in the present example, the main scanning drive unit 18 causes the print head 12 to perform an operation of ejecting ink while moving in the main scanning direction. Accordingly, the main scanning drive unit 18 causes the print head 12 to perform an operation of applying ink to the medium 50. The operation reception unit 20 is configured to receive a user's operation on the printing apparatus 10. In the present example, the operation reception unit 20 receives an instruction to feed the medium 50 from the user based on, for example, the user's operation on an input means such as a jog key. In this case, the instruction received by the operation reception unit 20 for feeding the medium 50 can be considered, for example, as an instruction conveyance instruction that causes the conveyance unit 16 to feed the medium 50 at a timing other than during printing.

[0022] The winding unit 22 is configured to wind the medium 50 at a position downstream of the transport unit 16 in the transport path where the medium 50 is transported in the printing device 10, and winds up the medium 50 from which ink has been ejected by the print head 12. In this example, the winding unit 22 has a rotary drive unit 202, a tension application unit 204, and a state detection unit 206. The rotary drive unit 202 is a drive unit that rotates the winding core 150 around which the medium 50 is wound. In this case, the winding core 150 in the winding unit 22 can be considered, for example, as a winding core that winds the medium 50 downstream of the transport unit 16 in the transport path. In this example, the rotary drive unit 202 has a motor that rotates the winding core 150, and while holding both ends of the winding core 150, rotates the winding core 150 around which the medium 50 is wound in a predetermined direction, thereby sequentially winding up the medium 50 that has passed the position facing the print head 12. In this case, the portion of the medium 50 that has passed the position facing the print head 12 can be considered, for example, the portion of a long, continuous piece of medium 50 that has passed the position facing the print head 12. In this example, the rotary drive unit 202 adjusts the linear velocity of the medium 50 based on the control of the control unit 30, for example, as shown as velocity V2 in the figure. In this case, the linear velocity can be considered, for example, the speed at which the medium 50 moves at the outermost position of the medium roll around which the medium 50 is wound on the core 150. In this example, this linear velocity is an example of roll position velocity. The roll position velocity can be considered, for example, the speed at which the medium 50 moves in accordance with the rotation of the core 150 at the outermost position of the medium 50 wound on the core 150.

[0023] The tension-applying unit 204 is configured to apply tension to the medium 50 being wound onto the core 150. In this example, the tension-applying unit 204 has a tension bar 212 and a bar-holding unit 214, and applies tension to the medium 50 between the medium roll and the conveying unit 16 by bringing the tension bar 212 into contact with the medium 50. The tension bar 212 is a rod-shaped member that contacts the medium 50 with its longitudinal direction parallel to the axial direction of the core 150. The bar-holding unit 214 is configured to hold the tension bar 212 so that it can move along a predetermined movement path. In this example, the bar-holding unit 214 adjusts the tension applied to the medium 50 by the tension bar 212 using a counterweight or spring, and holds the tension bar 212 so that it can move along a movement path that rotates the tension bar 212 around the central axis of the core 150 with the longitudinal direction of the tension bar 212 parallel to the central axis of the core 150.

[0024] More specifically, in the winding section 22 of this example, the bar holding section 214 holds the tension bar 212 such that its movement path is between a lower limit position P0 and an upper limit position P3, as shown in the left diagram in Figure 1(b), for example. In this case, the lower limit position P0 can be considered, for example, as the position where the height of the tension bar 212 (height in the direction of gravity) is at its minimum along the movement path of the tension bar 212. The upper limit position P3 can be considered, for example, as the position where the height of the tension bar 212 is at its maximum along the movement path of the tension bar 212. In this case, the lower limit position P0 and the upper limit position P3 can also be considered, for example, as the lower and upper limits of the range in which the position of the tension bar 212 can be adjusted by the operation of the rotation drive section 202. The lower limit position P0 and the upper limit position P3 can also be considered, for example, as the positions where the tension bar 212 will no longer function properly once it reaches those positions. Furthermore, in the movement path of the tension bar 212 in the winding section 22 of this example, an operation start trigger position P1 and an operation stop trigger position P2 are further set between the lower limit position P0 and the upper limit position P3, as shown in the figure. In this case, the operation start trigger position P1 is an example of a first position that is set in advance in the movement path. The operation stop trigger position P2 is an example of a second position that is different from the first position.

[0025] Furthermore, in the winding unit 22, the start trigger position P1 is closer to the lower limit position P0 than the stop trigger position P2. The stop trigger position P2 is closer to the upper limit position P3 than the start trigger position P1. In this case, if we consider the direction in which the transport unit 16 rotates the winding core 150 in accordance with the direction in which the medium 50 is fed as the forward direction, then in the forward rotation direction around the axis of the winding core 150, the stop trigger position P2 can be considered to be, for example, a position upstream of the start trigger position P1. In the winding unit 22, the fact that the stop trigger position P2 is upstream of the start trigger position P1 in the forward rotation direction can be considered, for example, that the stop trigger position P2 is at a higher position than the start trigger position P1.

[0026] The state detection unit 206 is configured to detect the state used to control the operation of the rotation drive unit 202. In this example, the state detection unit 206 detects at least the roll diameter (winding diameter), which is the diameter of the medium 50 wound on the core 150, and the state of the tension application unit 204. In this case, the roll diameter can be considered, for example, the diameter of the medium roll at the outermost circumference of the medium 50 wound on the core 150. The state detection unit 206 also detects, for example, at least the position of the tension bar 212 in the movement path of the tension bar 212 as the state of the tension application unit 204. More specifically, in this example, the state detection unit 206 acquires the positional relationship of the tension bar 212 with respect to the lower limit position P0, the operation start trigger position P1, the operation stop trigger position P2, and the upper limit position P3 as the position of the tension bar 212 in the movement path. In this case, the state detection unit 206 detecting the position of the tension bar 212 can be considered to correspond to, for example, detecting the depth of the deflection of the medium 50. Alternatively, the state detection unit 206 may detect the position of the tension bar 212 based on the output of a known multi-stage sensor, such as a pseudo-encoder or a rotary encoder.

[0027] The feeding unit 24 is configured to feed the medium 50 at a position upstream of the transport unit 16 in the transport path of the medium 50, and feeds the medium 50 toward a position facing the print head 12. In this example, the feeding unit 24 has a rotary drive unit 202, a tension application unit 204, and a state detection unit 206. Except for the points described below, the rotary drive unit 202, tension application unit 204, and state detection unit 206 in the feeding unit 24 have the same or similar characteristics as the rotary drive unit 202, tension application unit 204, and state detection unit 206 in the winding unit 22. In the feeding unit 24 of this example, the rotary drive unit 202 rotates the winding core 150 around which the medium 50 is wound in a predetermined direction, thereby sequentially feeding the medium 50 toward a position facing the print head 12. In this case, the core 150 in the feeding unit 24 can be considered, for example, as a core that feeds the medium 50 upstream of the transport unit 16 in the transport path. In the feeding unit 24, the rotary drive unit 202 adjusts the linear speed of the medium 50, for example, as shown as speed V3 in the figure, based on the control of the control unit 30. In the feeding unit 24, the bar holding unit 214 holds the tension bar 212 such that the movement path is between the lower limit position P0 and the upper limit position P3, for example, as shown in the right-hand figure in Figure 1(b). In the movement path of the drive roller 102 in the feeding unit 24, between the lower limit position P0 and the upper limit position P3, an operation start trigger position P1 and an operation stop trigger position P2 are set, for example, as shown in the figure, in a different order than that of the winding unit 22.

[0028] More specifically, in the feeding unit 24, the start trigger position P1 is closer to the upper limit position P3 than the stop trigger position P2. The stop trigger position P2 is closer to the lower limit position P0 than the start trigger position P1. In this case as well, in the forward rotational direction around the axis of the winding core 150, the stop trigger position P2 can be considered to be, for example, a position upstream of the start trigger position P1. In the feeding unit 24, the fact that the stop trigger position P2 is upstream of the start trigger position P1 in the forward rotational direction can be considered, for example, that the stop trigger position P2 is lower than the start trigger position P1. Also, in the feeding unit 24 of this example, the state detection unit 206 acquires the positional relationship of the tension bar 212 with respect to the lower limit position P0, the start trigger position P1, the stop trigger position P2, and the upper limit position P3 as the position of the tension bar 212 in the movement path.

[0029] The control unit 30 is, for example, the part of the printing device 10 that includes the CPU, and controls the operation of each part of the printing device 10. More specifically, in this example, the control unit 30 controls the operation of each part of the printing device 10 based on user instructions received based on user operations to the operation reception unit 20. The control unit 30 also controls the transport of the medium 50 by, for example, controlling the operation of the transport drive unit 106 in the transport unit 16 and the operation of the rotary drive unit 202 in the winding unit 22 and the feed unit 24. Furthermore, regarding the control of the transport of the medium 50, in this example, the control unit 30 makes the control performed on the rotary drive unit 202 in the winding unit 22 and the feed unit 24 different during printing and during instruction transport. In this case, during printing, for example, it can be considered the timing when printing is performed by having the print head 12 repeat the main scanning operation and the sub-scanning operation. During instruction transport, for example, it can be considered the timing when the medium 50 is sent based on instructions received by the operation reception unit 20 from the user at times other than printing. Furthermore, in this case, during the execution of the main scanning operation during printing, the control unit 30 stops the operation of feeding the medium 50 to the transport unit 16. Therefore, the operation of transporting the medium 50 during printing can be considered to be, for example, an operation of transporting the medium 50 intermittently. In contrast, during instructed transport, it is conceivable that, for example, the medium 50 may be transported continuously for a longer period of time based on the user's instructions. Therefore, the control performed by the control unit 30 in this example regarding the transport of the medium 50 can be considered to differ, for example, between intermittent transport of the medium 50 and continuous transport of the medium 50. More specifically, in this example, the control unit 30 performs control of the rotary drive unit 202 during printing and instructed transport, for example, as shown in Figures 2 and 3.

[0030] Figure 2 is a simplified flowchart showing an example of the control performed by the control unit 30 on the rotary drive unit 202 during printing. Regarding control during printing, in this example, the control unit 30 controls the rotary drive units 202 of the winding unit 22 and the feeding unit 24 asynchronously with the operation of the transport unit 16. Regarding the linear velocity of the medium 50 during the rotational drive that drives the winding core 150 with the rotary drive unit 202, a constant speed that is larger than the transport speed V1 at the transport unit 16 is used as the linear velocity V2 of the medium 50 in the winding unit 22. Similarly, a constant speed that is larger than the transport speed V1 at the transport unit 16 is used as the linear velocity V3 of the medium 50 in the feeding unit 24. With this configuration, for example, the implementation of control for the rotary drive unit 202 during printing can be easily and appropriately carried out.

[0031] More specifically, in this case, at the start of the printing operation, the tension bar 212 is raised to the operation stop trigger position P2 by an initialization operation performed, for example, when the power of the printing device 10 is turned on. At this point, the control unit 30 controls the operation of the rotary drive unit 202 so as to hold the winding core 150 without rotating it. In this case, it can be considered that the control unit 30 controls the rotary drive unit 202 so as to stop the rotation of the winding core 150. Also, in this case, once the printing operation starts, the medium 50 is transported intermittently by sub-scanning operations performed between main scanning operations, causing the tension bar 212 to gradually move from the operation stop trigger position P2 to the operation start trigger position P1 in both the winding unit 22 and the unwinding unit 24. In this case, based on the position of the tension bar 212 detected by the state detection unit 206, the control unit 30 maintains a state in which the rotation of the winding core 150 is stopped until the tension bar 212 reaches the operation start trigger position P1 (S102, No). When the tension bar 212 reaches the operation start trigger position P1 (S102, Yes), the control unit 30 causes the rotation drive unit 202 to perform rotational drive to rotate the winding core 150 in the forward direction (S104). In this case, as explained above, the rotation drive unit 202 rotates the winding core 150 based on the control of the control unit 30 such that the linear speed V2 in the winding unit 22 and the linear speed V3 in the unwinding unit 24 are faster than the transport speed V1 at the transport unit 16. In this case, the tension bar 212 moves in the direction from the operation start trigger position P1 to the operation stop trigger position P2.

[0032] In this case, the control unit 30 maintains the state in which the rotation drive unit 202 rotates the core 150 until the tension bar 212 reaches the operation stop trigger position P2, based on the position of the tension bar 212 detected by the state detection unit 206 (S106, No). When the tension bar 212 reaches the operation stop trigger position P2 (S106, Yes), the control unit 30 stops the rotation of the core 150 by the rotation drive unit 202 (S108), returns to the operation of step S102, and repeats the subsequent operations. With this configuration, for example, the winding unit 22 and the unwinding unit 24 can easily and appropriately wind and unwind the medium 50 in accordance with the operation of the transport unit 16 to intermittently transport the medium 50. Furthermore, this enables appropriate transport of the medium 50 during printing, for example.

[0033] However, when controlling the transport operation of the medium 50 with such asynchronous control, if the transport of the medium 50 is performed suddenly and continuously, for example, there may not be enough time for the winding amount and unwinding amount of the medium 50 in the winding unit 22 and unwinding unit 24 to keep up with the amount of the medium 50 transported in the transport unit 16. Therefore, in this example, as explained above, the control unit 30 performs different controls on the rotary drive unit 202 in the winding unit 22 and unwinding unit 24 during printing and during instruction transport. In this case, the control unit 30 controls the operation of the rotary drive unit 202 by, for example, the operation shown in Figure 3.

[0034] Figure 3 is a simplified flowchart showing an example of the control performed by the control unit 30 on the rotary drive unit 202 during instruction transport. As explained above, in the case of control during printing, at certain timings, the control unit 30 causes the rotary drive unit 202 to stop the rotation of the winding core 150. In contrast, in the instruction transport control in this example, the control unit 30 causes the rotary drive unit 202 to perform rotational driving to rotate the winding core 150 without stopping its rotation. In this case, the control unit 30 also changes the rotational speed (angular velocity) of the winding core 150 so that the linear velocity of the medium 50 changes based on the position of the tension bar 212. More specifically, in this case as well, at the start of the printing operation (just before the start), the tension bar 212 is raised to the operation stop trigger position P2 by an initialization operation performed, for example, when the power of the printing device 10 is turned on. Furthermore, at this point, the control unit 30 controls the operation of the rotation drive unit 202, for example, to hold the winding core 150 without rotating it.

[0035] In the case of instructed transport, the control unit 30 starts controlling the transport operation based on user instructions received, for example, by the operation reception unit 20. In this case, at the start of the operation to start transporting the medium to the transport unit 16, the control unit 30 starts the rotational drive of the winding core 150 by the rotational drive units 202 in the winding unit 22 and the unwinding unit 24. In this case, the control unit 30 causes the rotational drive units 202 to rotate the winding core 150 at a preset speed so that the winding core 150 rotates in the forward direction at a speed such that the tension bar 212 moves from the operation stop trigger position P2 to the operation start trigger position P1. More specifically, in this case, the control unit 30 causes the rotational drive units 202 in the winding unit 22 and the unwinding unit 24 to rotate the winding core 150 so that the linear velocities (V2, V3) of the medium 50 in the winding unit 22 and the unwinding unit 24 are smaller than the transport speed V1 of the medium 50 at the position of the transport unit 16.

[0036] In this case, based on the position of the tension bar 212 subsequently detected by the state detection unit 206, the control unit 202 controls the operation of the rotation drive unit 202 to maintain a constant linear velocity of the medium 50 until the tension bar 212 reaches the operation start trigger position P1 (S202, No). In this example, maintaining a constant linear velocity can be considered as maintaining a substantially constant linear velocity according to the accuracy required to properly transport the medium 50. Furthermore, if the tension bar 212 does not move in the expected direction, for example, while maintaining a constant linear velocity, the control unit 30 may, for example, adjust the linear velocity. In this case, the control unit 30 maintains a constant linear velocity by, for example, maintaining the adjusted linear velocity.

[0037] Then, when the tension bar 212 reaches the operation start trigger position P1 (S202, Yes), the control unit 30 instructs the rotation drive unit 202 to change the rotation speed of the winding core 150 (increase speed) so that the linear velocity increases (S204). In this case, the rotation drive unit 202 changes the rotation speed of the winding core 150 so that the linear velocity of the tension bar 212 moves in the direction from the operation start trigger position P1 to the operation stop trigger position P2, based on the control of the control unit 30. More specifically, in this case, the control unit 30 instructs the rotation drive unit 202 to change the rotation speed of the winding core 150 so that the linear velocity (V2, V3) is greater than the transport speed V1 of the medium 50 at the position of the transport unit 16. Also, in step S204 of this example, the control unit 30 acquires and records (stores) the timing (current time) when the tension bar 212 reaches the operation start trigger position P1 as part of the parameters used in the feedback control which will be explained in detail later. The control unit 30 then determines the linear velocity after the speed increase using this feedback control. The feedback control for determining the linear velocity will be explained in more detail later.

[0038] In this case, the control unit 30 maintains a constant linear velocity of the medium 50 based on the position of the tension bar 212 detected by the state detection unit 206 until the tension bar 212 reaches the operation stop trigger position P2 (S206, No). When the tension bar 212 reaches the operation stop trigger position P2 (S206, Yes), the control unit 30 causes the rotation drive unit 202 to change the rotation speed of the winding core 150 (speed down) so that the linear velocity decreases (S208). In this case, the rotation drive unit 202 changes the rotation speed of the winding core 150 based on the control of the control unit 30 so that the linear velocity of the tension bar 212 moves in the direction from the operation stop trigger position P2 to the operation start trigger position P1. More specifically, in this case, the control unit 30 causes the rotation drive unit 202 to change the rotation speed of the winding core 150 so that the linear velocity (V2, V3) is smaller than the transport speed V1 of the medium 50 at the position of the transport unit 16. In this example, for example, a predetermined constant linear velocity is used as the linear velocity. Furthermore, in step S208 of this example, the control unit 30 acquires and records (stores) the timing (current time) when the tension bar 212 reaches the operation stop trigger position P2 as a parameter to be used in the above-mentioned feedback control.

[0039] Furthermore, following the operation in step S208, the control unit 30 returns to the operation in step S202 and repeats the subsequent operations. Even with this configuration, for example, the winding and unwinding operations of the medium 50 in the winding unit 22 and the unwinding unit 24 can be appropriately controlled. In this case, for example, by using control that starts the rotation of the winding core 150 in the winding unit 22 and the unwinding unit 24 in conjunction with the start of transport in the transport unit 16 and does not stop the rotation of the winding core 150, transport can be controlled more appropriately even when transporting the medium 50 continuously. In this case, the control performed by the control unit 30 during instructed transport can be considered as, for example, a semi-synchronous operation in which the operation of the winding unit 22 and the unwinding unit 24 is started in conjunction with the start of operation of the transport unit 16. In addition, in this example, for example, by determining the linear velocity of the medium 50 by feedback control based on the timing when the tension bar 212 reaches the operation start trigger position P1 and the operation stop trigger position P2, the linear velocity of the medium 50 in the winding unit 22 and the unwinding unit 24 can be adjusted more appropriately. In this case, in step S204, the control unit 30 determines the linear velocity such that, for example, the travel time for the tension bar 212 to move from the operation start trigger position P1 to the operation stop trigger position P2 is longer.

[0040] Here, the operation of the control unit 30 during instruction transport as described above can be considered as, for example, detecting the movement time required for the tension bar 212 to move from the operation start trigger position P1 to the operation stop trigger position P2 based on the position of the tension bar 212 detected by the state detection unit 206, and changing the core rotation speed, which is the rotation speed at which the rotation drive unit 202 rotates the core 150, based on this movement time. In this case, the operation of the control unit 30 during instruction transport can also be considered as, for example, controlling the operation of the rotation drive unit 202 based on the movement time. Furthermore, during instruction transport, the control unit 30 detects the movement time of the tension bar 212 based on the current time acquired in steps S204 and S208, for example. Then, the control unit 30 changes the core rotation speed based on this movement time. In this case, by changing the core rotation speed based on this movement time, the core rotation speed can be appropriately changed to match the actual movement of the tension bar 212 that occurs when the medium 50 is transported, for example.

[0041] Therefore, according to this example, the transport operation of the medium 50 can be appropriately stabilized when transporting the medium under various conditions, such as when transporting the medium 50 suddenly and continuously. Furthermore, this allows for more appropriate transport of the medium 50 in the printing apparatus 10. In this example, the range between the start trigger position P1 and the stop trigger position P2 in the movement path of the tension bar 212 can be considered, for example, as a target range for the position of the tension bar 212. In this case, the operation of the control unit 30 when the tension bar 212 moves outside the target range can be considered, for example, as an operation to change the winding core rotation speed in the direction that brings the tension bar 212 back into the target range. More specifically, regarding the relationship between the target range and the position of the tension bar 212, in the winding unit 22 and the unwinding unit 24, if the tension bar 212 moves outside the target range from the side of the operation start trigger position P1, the control unit 30 increases the winding core rotation speed so that the linear velocity (V2, V3) of the medium 50 becomes faster than the transport speed V1 at the position of the transport unit 16. Conversely, if the tension bar 212 moves outside the target range from the side of the operation stop trigger position P2, the control unit 30 decreases the winding core rotation speed so that the linear velocity (V2, V3) of the medium 50 becomes slower than the transport speed V1 at the position of the transport unit 16. With this configuration, for example, in the winding unit 22 and the unwinding unit 24, the winding core rotation speed can be appropriately changed to the speed at which the tension bar 212 returns to within the target range when the tension bar 212 reaches the edge of the target range. Furthermore, this allows for appropriate control of the position of the tension bar 212 in accordance with the target range.

[0042] Furthermore, when comparing the operation of the control unit 30 during printing and instruction transport as explained using Figures 2 and 3, it can be considered that there is a difference in whether or not control is performed based on the movement time of the tension bar 212 (the movement time it takes for the tension bar 212 to move from the operation start trigger position P1 to the operation stop trigger position P2). In this case, during printing in this example, the control unit 30 controls the operation of the rotary drive unit 202 without relying on the movement time. With this configuration, during printing, for example, the transport of the medium 50 can be appropriately controlled with simpler control. In contrast, during instruction transport in this example, the control unit 30 controls the operation of the rotary drive unit 202 based on the movement time, as explained above. With this configuration, it can be considered that the transport of the medium 50 can be controlled more appropriately, for example, when the medium 50 is transported continuously.

[0043] Furthermore, regarding the control of the control unit 30 during printing and instruction transport, it can be considered that there are differences in more specific operations. In this regard, in both cases, during printing and instruction transport, regarding the operation of the control unit 30 when the tension bar 212 moves from the operation stop trigger position P2 to the operation start trigger position P1 (operation after the tension bar 212 reaches the operation start trigger position P1), it can be considered that, for example, the tension bar 212 is moved toward the operation stop trigger position P2 by rotating the winding core 150 in the forward direction. With this configuration, for example, the direction of movement of the tension bar 212 can be appropriately reversed when the tension bar 212 reaches the operation start trigger position P1. However, even in this case, if we focus on more specific control, it can be considered that there are differences in the operation of the control unit 30 between printing and instruction transport.

[0044] More specifically, during printing, when the tension bar 212 moves from the operation stop trigger position P2 to the operation start trigger position P1, the control unit 30 moves the tension bar 212 toward the operation stop trigger position P2 by rotating the core 150 in the rotary drive unit 202 so that the linear velocity (V1, V2) of the medium 50 becomes faster than the transport speed V1 at the position of the transport unit 16. In this case, the control unit 30 rotates the core 150 in the rotary drive unit 202 to achieve a preset linear velocity, regardless of the movement time of the tension bar 212. With this configuration, for example, during printing, the direction of movement of the tension bar 212 that has reached the operation start trigger position P1 can be appropriately reversed with simple control. In contrast, during instruction transport, if the tension bar 212 moves from the operation stop trigger position P2 to the operation start trigger position P1, the control unit 30 moves the tension bar 212 toward the operation stop trigger position P2 by rotating the winding core 150 at a rotational speed determined by feedback control, which will be explained in more detail later, based on the movement time of the tension bar 212. With this configuration, for example, even during instruction transport, the direction of movement of the tension bar 212 can be appropriately reversed for the tension bar 212 that has reached the operation start trigger position P1.

[0045] Furthermore, the operation of the control unit 30 when the tension bar 212 moves from the start trigger position P1 to the stop trigger position P2 (the operation after the tension bar 212 reaches the stop trigger position P2) can also be considered to differ, for example, between printing and instruction transport. More specifically, as explained above, in the printing phase of this example, when the tension bar 212 moves from the start trigger position P1 to the stop trigger position P2, the control unit 30 stops the rotation of the core 150 by the rotation drive unit 202, thereby moving the tension bar 212 toward the start trigger position P1. With this configuration, for example, during printing, the direction of movement of the tension bar 212 that has reached the stop trigger position P2 can be appropriately reversed with simple control. In contrast, when the tension bar 212 moves from the start trigger position P1 to the stop trigger position P2 during instruction transport, the control unit 30, for example, causes the rotation drive unit 202 to perform a rotation drive that rotates the winding core 150 at the rotation speed at which the tension bar 212 moves toward the start trigger position P1, without stopping the rotation of the winding core 150. With this configuration, for example, when transporting the medium continuously during instruction transport, the direction of movement of the tension bar 212 that has reached the stop trigger position P2 can be reversed more appropriately.

[0046] Next, focusing on the overall operation of the printing device 10, we will explain in more detail the control performed by the control unit 30 during instructed transport. Figure 4 is a simplified flowchart showing an example of the control performed by the control unit 30 during instructed transport, focusing on the overall operation of the printing device 10. When instructed transport is performed, the control unit 30, for example, based on the user's instruction received at the operation reception unit 20, turns on the motor in the transport drive unit 106 of the transport unit 16 to start transporting the medium 50 to the transport unit 16 (S302). In this example, the control unit 30 also turns on the motors of the rotary drive unit 202 in the feed unit 24 and the rotary drive unit 202 in the winding unit 22 in conjunction with the start of transport of the medium 50 in the transport unit 16 (S304, S306). Furthermore, this causes the control unit 30 to start the rotational drive of the winding core 150 in the rotational drive units 202 in the winding unit 22 and the unwinding unit 24 at the timing when the instruction transport operation begins.

[0047] In this case, while the motor of the transport drive unit 106 in the transport unit 16 is on (S308, Yes), the control unit 30 continues to monitor and control the unwinding unit 24 and the winding unit 22 (S310, S312). More specifically, in this example, the control unit 30 performs, for example, the operation during instructed transport as described with reference to Figure 3, as monitoring and control of the winding unit 22 and the unwinding unit 24. In this case, for example, if the operation reception unit 20 receives an instruction to end instructed transport, the control unit 30 turns off the motor of the transport drive unit 106 in the transport unit 16 (S308, No), and ends the operation during instructed transport. With this configuration, the control unit 30 can appropriately control during instructed transport.

[0048] Next, we will explain in more detail the control performed by the control unit 30 during instruction transport, and the feedback control for determining the linear velocity of the medium 50 during instruction transport. Figure 5 is a diagram illustrating the multiple states that are distinguished according to the position of the tension bar 212 during instruction transport. As explained above, during instruction transport, the control unit 30 controls the linear velocity of the medium 50 in the winding unit 22 and the feeding unit 24, for example, by setting the range between the operation start trigger position P1 and the operation stop trigger position P2 in the movement path of the tension bar 212 as the target range for the position of the tension bar 212. However, in the actual operation of the printing device 10, the position of the tension bar 212 may deviate significantly from the target range due to various factors. Therefore, in this example, the control unit 30 controls the operation of the rotary drive unit 202, etc. in the winding unit 22 and the feeding unit 24, including controls other than those explained above using Figure 3, etc. Furthermore, in this example, the control unit 30 distinguishes between multiple states according to the position of the tension bar 212, such as states a to e shown in the figure, and controls the rotation drive unit 202 based on a predetermined criterion for each state.

[0049] In this regard, as explained above, in the winding unit 22 and the unwinding unit 24 of this example, the bar holding unit 214 holds the tension bar 212 such that the movement path is between the lower limit position P0 and the upper limit position P3. Also, in this example, the operation start trigger position P1 and the operation stop trigger position P2 are set between the lower limit position P0 and the upper limit position P3. In this case, the state of the medium 50 at the position of the tension bar 212 will differ due to the influence of the tension applied to the tension bar 212, etc., depending on the position of the tension bar 212 in the movement path. In this case, the state detection unit 206 in the winding unit 22 and the unwinding unit 24 can be considered to detect, for example, the presence or absence of deflection of the medium 50 and the state of deflection based on the position of the tension bar 212.

[0050] More specifically, for example, as shown in state c in the figure, if the tension bar 212 is between the target range, which is the start trigger position P1 and the stop trigger position P2, then the state of the medium 50 can be considered appropriate. In this case, the control unit 30 controls the operation of the rotary drive unit 202 to maintain the linear velocity of the medium 50 until the tension bar 212 reaches the start trigger position P1 or the stop trigger position P2, for example, by performing the control described above using Figure 3. However, in this case, the linear velocity is proportional to the roll diameter. In this case, for example, it is necessary to appropriately adjust the rotational speed (angular velocity) of the winding core 150 in accordance with the change in roll diameter caused by the progress of conveying. For this reason, the control unit 30 appropriately reduces the rotational speed of the winding core 150 in accordance with the increase in roll diameter caused by the progress of winding, for example, for the winding unit 22. Also, the control unit 30 appropriately accelerates the rotational speed of the winding core 150 in accordance with the decrease in roll diameter caused by the progress of unwinding, for example, for the unwinding unit 24.

[0051] Furthermore, as shown in state b in the figure, when the tension bar 212 is located closer to the lower limit position P0 than the target range, the state of the medium 50 can be considered to be, for example, loose due to flexing. In this case, the control unit 30 controls the operation of the rotation drive unit 202 so that, for example, the rotation speed of the winding core 150 changes in a direction that eliminates the flexing of the medium 50. More specifically, in this case, the control unit 30 accelerates the rotation speed of the winding core 150 with respect to the winding unit 22. Also, the control unit 30 decelerates the rotation speed of the winding core 150 with respect to the unwinding unit 24. With this configuration, for example, the tension bar 212 can be appropriately returned to the target range. Furthermore, as shown in state d in the figure, when the tension bar 212 is located closer to the upper limit position P3 than the target range, the state of the medium 50 can be considered to be tight. In this case, the control unit 30 controls the operation of the rotation drive unit 202 so that, for example, the rotation speed of the winding core 150 changes in a direction that loosens the tension of the medium 50. More specifically, in this case, the control unit 30 reduces the rotational speed of the winding core 150 relative to the winding unit 22. Conversely, the control unit 30 accelerates the rotational speed of the winding core 150 relative to the unwinding unit 24. With this configuration, for example, the tension bar 212 can be appropriately returned to the target range.

[0052] Furthermore, as shown in states a and e in the figure, if the tension bar 212 reaches the lower limit position P0 or the upper limit position P3, or a position beyond these, it can be considered that some kind of abnormality has occurred. For example, if the tension bar 212 reaches the lower limit position P0, it can be considered that the medium 50 is in an excessively loose state. In this case, the control unit 30 controls the operation of the rotation drive unit 202 so that, for example, the rotation speed of the winding core 150 changes in a direction that eliminates the deflection of the medium 50. Also, in this case, for example, if the position of the tension bar 212 does not return to a position higher than the lower limit position P0 even after a certain period of time has elapsed, appropriate error processing is performed. As for error processing, for example, all motors used to transport the medium 50 may be stopped to terminate the operation abnormally. More specifically, in this case, the control unit 30 may, for example, set the rotation speed of the winding core 150 to the maximum speed for the winding unit 22. If the tension bar 212 does not rise after a certain period of time, the control unit 30 determines, for example, that winding is not being performed properly and performs error processing. The control unit 30 also stops the rotation of the winding core 150 in the dispensing unit 24. If the tension bar 212 does not rise after a certain period of time, the control unit 30 determines, for example, that the dispensing of the medium 50 is not being performed properly due to excessive dispensing, and performs error processing. Furthermore, if the tension bar 212 reaches the upper limit position P3, it is possible that the position of the tension bar 212 cannot be controlled. For this reason, it is preferable that the control unit 30 immediately stops the transport operation by performing error processing when the tension bar 212 reaches the upper limit position P3.

[0053] Furthermore, when performing continuous transport, the position of the tension bar 212 at the start of the operation may change depending on the operation performed immediately before. Therefore, in this case, it is preferable to start the control according to each of the above conditions, for example, in accordance with the position of the tension bar 212 at the start of the operation. Also, for example, if the medium 50 was being transported intermittently by an operation such as printing immediately before starting continuous transport, the tension bar 212 can usually be considered to be at a position somewhere between the operation start trigger position P1 and the operation stop trigger position P2. In this case, for example, it can be considered that there is a high probability that the tension bar 212 is near the operation stop trigger position P2.

[0054] Furthermore, as control performed by the control unit 30 in response to each state, for example, the control shown in Figure 6 can be considered. Figure 6 is a table showing an example of control performed by the control unit 30 during instruction transport. In this table, the upper table shows an example of control performed by the control unit 30 on the winding unit 22. The lower table shows an example of control performed by the control unit 30 on the unwinding unit 24. The processes shown in the ENTRY column are processes executed when a change in state occurs for states a to e. The processes shown in the TIMERCALL column are processes executed periodically by timer processing while the current state continues. More specifically, in this example, the control unit 30 periodically checks, for example, by timer processing whether a change has occurred in the current state for states a to e shown in Figure 5. If a change in state has occurred, the control unit 30 executes the process shown in the ENTRY column for the new state after the change. If no change has occurred in the current state, the control unit 30 executes the process shown in the TIMERCALL column for the current state. With this configuration, for example, the control unit 30 can appropriately execute the processing corresponding to each state shown in Figure 5.

[0055] Here, the flowchart in Figure 3 described above can be considered as a simplified representation of the operation, focusing on, for example, a part of the process shown in Figure 6. In this case, regarding the operation of the winding unit 22 (winding side), the operation in step 202 of Figure 3 can be considered to correspond to, for example, the operation of detecting a transition from state c to state b. The speed-up operation and the operation of recording the current time performed in step S204 of Figure 3 can be considered to correspond to, for example, the processing of the ENTRY item in state b. Furthermore, the operation in step 206 of Figure 3 can be considered to correspond to, for example, the operation of detecting a transition from state c to state d. The speed-down operation performed in step S208 of Figure 3 can be considered to correspond to, for example, the processing of the ENTRY item in state d. In this case, the operation of recording the current time in step S208 of Figure 3 can be considered to correspond to, for example, the processing performed when the current location matches the operation stop trigger position P2 in the TIMERCALL item of state c.

[0056] Similarly, regarding the operation of the feeding unit 24 (feeding side), the operation in step 202 in Figure 3 can be considered to correspond to, for example, the operation of detecting a transition from state c to state d. The speed-up operation and the operation of recording the current time performed in step S204 in Figure 3 can be considered to correspond to, for example, the processing of the ENTRY item in state d. The operation in step 206 in Figure 3 can be considered to correspond to, for example, the operation of detecting a transition from state c to state b. The speed-down operation performed in step S208 in Figure 3 can be considered to correspond to, for example, the processing of the ENTRY item in state b. In this case, the operation of recording the current time in step S208 in Figure 3 can be considered to correspond to, for example, the processing performed when the current location matches the operation stop trigger position P2 in the TIMERCALL item of state c. Furthermore, in the table in Figure 6, the processing other than those mentioned above can be considered to be, for example, processing to deal with unexpected movements of the tension bar 212.

[0057] Furthermore, as explained above, in this example, the control unit 30 adjusts the linear velocity of the medium 50 by determining the linear velocity of the medium 50 through feedback control based on the timing when the tension bar 212 reaches the operation start trigger position P1 and the operation stop trigger position P2. In this case, in step S204 of Figure 3, the control unit 30 determines the linear velocity after the speed increase through this feedback control, for example. Also, in this case, in Figure 6, for example, the operation of updating the reference velocity in the winding side state b and the unwinding side state d can be considered to correspond to the operation of determining the linear velocity after the speed increase. And in this case, for example, it is preferable to determine the linear velocity such that the travel time of the tension bar 212 moving from the operation start trigger position P1 to the operation stop trigger position P2 is as long as possible. Therefore, in this example, the control unit 30 calculates the travel time Tr required for the tension bar 212 to move from the start trigger position P1 to the stop trigger position P2, based on the current time recorded when the tension bar 212 reaches the start trigger position P1 and the stop trigger position P2, and determines the changed linear velocity based on the travel time Tr. In this case, for example, the control unit 30 calculates the travel time Tr by the difference in current time detected at the start trigger position P1 and the stop trigger position P2 at the timing when the tension bar 212 moved from the start trigger position P1 to the stop trigger position P2 immediately before.

[0058] More specifically, in this example, the control unit 30 updates the linear velocity shown as the reference velocity in the table in Figure 6, based on a preset finite constant value, the target time Tt, and the transport speed V1 of the medium 50 at the position of the transport unit 16. In this case, if the linear velocity before the change due to the feedback process is V and the linear velocity after the change is V', then N = Tt / Tr, and the control unit 30 uses, for example, the following equation V'={(N-1)V1+V} / N The modified linear velocity V' is calculated using this formula. In this formula, V and V' correspond, for example, to the reference velocity V20 shown in the winding side state b and the reference velocity V30 shown in the unwinding side state d in the table in Figure 6. Furthermore, these reference velocity V20 and V30 can be considered as corresponding to, for example, the linear velocities V2 and V3 shown in Figure 1.

[0059] In this case, the initial values ​​of the reference speeds V20 and V30 could be set to speeds that are preset so that the tension bar 212 moves from the start trigger position P1 to the stop trigger position P2 while the transport unit 16 is transporting the medium 50 at transport speed V1. As initial values ​​for such reference speeds V20 and V30, it is conceivable to use speeds that are set considering the linear velocity of the medium 50 used in the winding unit 22 and the feeding unit 24 during printing operations in which the medium 50 is transported intermittently.

[0060] More specifically, in this case, for example, consider a state in which the winding core 150 is held without rotation in the winding unit 22 and the unwinding unit 24, and in that state the medium 50 is transported in the transport unit 16 at a transport speed V1, and the time required for the tension bar 212 to move from the operation stop trigger position P2 to the operation start trigger position P1 is defined as T21. Also, regarding the winding side, let V2 be the linear speed of the medium 50 used in the winding unit 22 during printing, and consider a state in which the medium 50 is wound at a linear speed of V2 without transporting the medium 50 in the transport unit 16, and in that state the time required for the tension bar 212 to move from the operation start trigger position P1 to the operation stop trigger position P2 is defined as T12. In this case, the initial value of the reference speed V20 on the winding side can be, for example, a speed calculated as V20 = (T21 / T12) × V2. Similarly, with respect to the unwinding side, let V3 be the linear velocity of the medium 50 used in the winding unit 22 during printing. Consider a state where the medium 50 is unwinded at a linear velocity of V3 without the medium 50 being transported by the transport unit 16, and let T12 be the time required for the tension bar 212 to move from the start trigger position P1 to the stop trigger position P2 in that state. In this case, the initial value of the reference speed V30 on the unwinding side can be set to a speed calculated as, for example, V30 = (T21 / T12) × V3. With this configuration, for example, the initial values ​​of the linear velocity (reference speed) on the winding side and the unwinding side can be appropriately set.

[0061] Furthermore, as explained above, in this example, the above-described feedback processing is performed to increase the travel time of the tension bar 212 as it moves from the start trigger position P1 to the stop trigger position P2. For this reason, the control unit 30 may only perform the change in linear velocity due to the feedback processing if, for example, the travel time Tr is longer than the previous time. In this case, the control unit 30 compares the newly detected travel time Tr with the previous Tr based on the history of travel time Tr. Then, at the timing of a transition to winding state b or unwinding state d, if, for example, the most recent travel time Tr is longer than the previous travel time Tr, the control unit 30 changes the linear velocity using the feedback processing described above. Conversely, if, for example, the most recent travel time Tr is longer than the previous travel time Tr, the control unit 30 does not perform the above-described feedback processing and returns the linear velocity to, for example, the previous linear velocity. With this configuration, for example, the feedback processing to increase the travel time Tr can be performed more appropriately.

[0062] Furthermore, the feedback processing operation described above can be considered, for example, as the operation when the tension bar moves outside the target range from the operation start trigger position P1. In this case, the operation of the control unit 30 can be considered as changing the rotational speed of the winding core 150 in the winding unit 22 and the unwinding unit 24 based on the movement time Tr detected when the tension bar 212 immediately reached the operation stop trigger position P2, thereby moving the tension bar 212 toward the operation stop trigger position P2. With this configuration, for example, the linear velocity of the medium 50 and the rotational speed of the winding core 150 in the winding unit 22 and the unwinding unit 24 can be appropriately changed in accordance with the actual movement of the tension bar 212 when the medium 50 is transported. In addition, this makes it possible to transport the medium 50 more appropriately, for example, when the medium 50 is transported continuously during instructed transport.

[0063] Furthermore, in this case, the state detection unit 206 can appropriately acquire information necessary for control during instruction transport by using only the same or similar sensors as those used when transporting the medium 50 in asynchronous operation, such as during printing. Therefore, according to this example, continuous transport of the medium 50 can be performed more appropriately without increasing the cost of the hardware configuration of the printing device 10. In addition, in this case, the feedback processing described above makes it possible to implement the system with simple and low-load calculations, for example.

[0064] Next, we will provide supplementary explanations regarding the configuration described above, as well as explanations of modified examples. As explained above, during instructed transport, the control unit 30 of this example adjusts the linear speed in the winding unit 22 and the unwinding unit 24 through feedback processing. At first glance, it might seem that even without such feedback processing, if the linear speed in the winding unit 22 and the unwinding unit 24 is the same as the transport speed in the transport unit 16, continuous transport over long periods of time would be easier. However, in the winding unit 22 and the unwinding unit 24, the linear speed changes according to the roll diameter of the media roll and the angular velocity of the rotation of the winding core 150. This roll diameter gradually changes as the winding and unwinding of the media 50 progresses in the winding unit 22 and the unwinding unit 24. Therefore, it is usually difficult to reliably match the linear speed in the winding unit 22 and the unwinding unit 24 with the transport speed in the transport unit 16. In contrast, according to this example, continuous transport over long periods of time can be performed more appropriately with simpler control.

[0065] Furthermore, as explained above, in the feedback control of this example, a finite constant value is used as the target time Tt. In this regard, from the perspective of making the travel time Tr longer, it might seem preferable to make the target time infinite. However, in this case, the calculations performed in the feedback process may become more complex. In contrast, in this example, by using a finite value for the target time Tt, the feedback process can be performed more easily and appropriately.

[0066] As explained above, in this example, the state detection unit 206 detects at least the roll diameter of the media roll and the state of the tension application unit 204. In this case, the control unit 30 can appropriately change the rotation speed of the winding core 150 in accordance with the linear speed determined by the feedback process, for example, based on the roll diameter. In this case, it is preferable that the control unit 30 further changes the winding core 150 in accordance with the linear speed based on the thickness of the media 50. With this configuration, for example, the linear speed of the media 50 can be adjusted more appropriately. In this case, by having the control unit 30 perform control based on the roll diameter, for example, the fluctuation range of the change in linear speed in the initial stage of transport (start of movement) can be reduced, and more stable control can be achieved. In contrast, in a modified operation of the control unit 30, for example, the operation of the winding unit 22 and the unwinding unit 24 may be controlled without considering the roll diameter. In this case as well, for example, the operation of the winding unit 22 and the unwinding unit 24 can be appropriately controlled by adjusting the rotational speed of the winding core 150 using feedback processing based on the travel time Tr described above.

[0067] As explained above, in this example, the control unit 30 controls the operation of the rotary drive unit 202 based on the movement time of the tension bar 212 as it moves from the start trigger position P1 to the stop trigger position P2. In contrast, a specific modification of the operation of the control unit 30 could be, for example, to detect the movement time of the tension bar 212 as it moves from the stop trigger position P2 to the start trigger position P1, and to control the operation of the rotary drive unit 202 based on this movement time. Even with this configuration, for example, the operation of the rotary drive unit 202 can be appropriately controlled in accordance with the actual movement of the tension bar 212 when the medium 50 is transported. In this case, for example, the stop trigger position P2 can be considered as an example of a first position in the movement path of the tension bar 212. Also, for example, the start trigger position P1 can be considered as an example of a second position different from the first position.

[0068] Furthermore, the printing apparatus 10 in this example can also be considered as an example of a conveying device that conveys the medium 50 while adjusting the tension of the medium 50. In this case, the medium 50 can be considered as an example of a thin film sheet conveyed by the conveying device. The medium roll, in which the medium 50 is wound around the core 150, can be considered as an example of a sheet roll. In this case, the conveying device can also be considered as a device that adjusts the tension of the sheet using a tension bar on at least one of the winding side or the unwinding side. In this case as well, by performing the same or similar feedback control as described above, the conveying of the sheet can be made more appropriate. Furthermore, the control of this feedback process can also be considered as a control that can be applied to a configuration in which the operation of the winding section 22 and the unwinding section 24 is asynchronously controlled in relation to the operation of the configuration corresponding to the conveying section 16. [Industrial applicability]

[0069] The present invention can be suitably used, for example, in printing devices and the like. [Explanation of symbols]

[0070] 10...Printing device, 102...Drive roller, 104...Opposite roller, 106...Transport drive unit, 108...Driven roller, 12...Print head, 14...Platen, 150...Core, 16...Transport unit, 18...Main scanning drive unit, 20...Operation reception unit, 202...Rotation drive unit, 204...Tension application unit, 206...State detection unit, 212...Tension bar, 214...Bar holding unit, 22...Winding unit, 24...Feeding unit, 30...Control unit, 50...Medium

Claims

1. A printing apparatus that performs printing on a medium, A print head that applies colorant to the aforementioned medium, A transport unit that transports the medium in a predetermined transport direction so that the medium passes a position opposite the print head, A rotational drive unit that rotates the core around which the medium is wound at a position upstream or downstream of the transport unit in the transport path through which the medium is transported, A tension-applying unit is provided between the media roll, in which the media is wound around the core, and the conveying unit, which applies tension to the media. A state detection unit for detecting the state of the tension application unit, A control unit that controls the operation of the rotary drive unit and Equipped with, The tension-applying unit is, A tension bar, which is a rod-shaped member that contacts the medium with its longitudinal direction parallel to the axial direction of the winding core, A bar holding part that holds the tension bar so as to be movable along a predetermined movement path, It has, The state detection unit detects the position of the tension bar in the movement path, The printing apparatus is characterized in that the control unit detects the movement time, which is the time required for the tension bar to move from a preset first position to a second position different from the first position in the movement path, based on the position of the tension bar detected by the state detection unit, and changes the core rotation speed, which is the rotation speed at which the rotation drive unit rotates the core, based on the movement time.

2. A main scanning drive unit causes the print head to perform a main scanning operation, which moves the print head in a main scanning direction perpendicular to the transport direction of the medium at the position of the transport unit. An operation reception unit that receives instructions from the user to send the aforementioned medium. Furthermore, During printing in which the colorant is applied to the medium, the transport unit feeds the medium between the main scanning operations. The printing apparatus according to claim 1, wherein the control unit controls the winding core rotation speed differently during instruction transport, when the medium is sent based on an instruction received from the user by the operation reception unit at a time other than printing, and during printing, and during instruction transport, the control unit detects the travel time and changes the winding core rotation speed based on the travel time.

3. If the direction in which the transport unit rotates the core in accordance with the direction in which the medium is fed is defined as the forward direction, then in the forward rotation direction with respect to the axis of the core, the second position is a position that is upstream of the first position. During printing and instruction transport, if the tension bar moves from the second position to the first position, the control unit rotates the winding core in the forward direction to move the tension bar toward the second position. During the printing process, if the tension bar moves from the first position to the second position, the control unit stops the rotation of the core in the rotation drive unit, thereby moving the tension bar toward the first position. The printing apparatus according to claim 2, characterized in that, when the tension bar moves from the first position to the second position during the instruction transport, the control unit causes the rotation drive unit to perform a rotation drive that rotates the winding core at the rotation speed at which the tension bar moves toward the first position, without stopping the rotation of the winding core.

4. If the speed at which the medium moves at the position of the transport section is defined as the transport speed, and the speed at which the medium moves at the outermost position of the medium wound on the core in accordance with the rotation of the core is defined as the roll position speed, During the printing process, if the tension bar moves from the second position to the first position, the control unit rotates the core in the rotary drive unit so that the roll position speed is faster than the transport speed, thereby moving the tension bar toward the second position. The printing apparatus according to claim 3, characterized in that, when the tension bar moves from the second position to the first position during the instructed transport, the control unit rotates the core at the rotational speed determined based on the movement time detected at the timing when the tension bar reached the second position immediately before, thereby moving the tension bar toward the second position.

5. If the tension bar moves outside the target range, which is the range between the first position and the second position in the movement path, the control unit changes the winding core rotation speed in the direction that brings the tension bar back into the target range. Furthermore, the printing apparatus according to claim 1, characterized in that when the tension bar moves from the side of the first position to outside the target range, the control unit changes the core rotation speed based on the movement time detected at the timing when the tension bar immediately reached the second position.

6. The rotational drive unit rotates the winding core that winds the medium downstream of the transport unit in the transport path, If the speed at which the medium moves at the position of the transport section is defined as the transport speed, and the speed at which the medium moves at the outermost position of the medium wound on the core in accordance with the rotation of the core is defined as the roll position speed, The transport unit transports the medium at a constant transport speed, If the tension bar moves from the first position to outside the target range, the control unit increases the core rotation speed so that the roll position speed becomes faster than the transport speed. The printing apparatus according to claim 5, characterized in that when the tension bar moves from the side of the second position out of the target range, the control unit reduces the core rotation speed so that the roll position speed becomes slower than the transport speed.

7. The rotational drive unit rotates the winding core that dispenses the medium upstream of the transport unit in the transport path, If the speed at which the medium moves at the position of the transport section is defined as the transport speed, and the speed at which the medium moves at the outermost position of the medium wound on the core in accordance with the rotation of the core is defined as the roll position speed, The transport unit transports the medium at a constant transport speed, If the tension bar moves from the first position to outside the target range, the control unit increases the core rotation speed so that the roll position speed becomes faster than the transport speed. The printing apparatus according to claim 5, characterized in that when the tension bar moves from the side of the second position out of the target range, the control unit reduces the core rotation speed so that the roll position speed becomes slower than the transport speed.

8. A tension adjustment method for adjusting the tension of a medium used in a printing apparatus, The transport unit feeds the medium in a predetermined transport direction such that the medium passes through a position opposite to the print head that applies colorant to the medium. The core around which the medium is wound is rotated by a rotational drive unit at a position upstream or downstream of the transport unit in the transport path through which the medium is transported. Between the media roll in which the medium is wound around the core and the transport unit, tension is applied to the medium by the tension-applying unit, while the state of the tension-applying unit is detected by the state detection unit. The tension-applying unit is, A tension bar, which is a rod-shaped member that contacts the medium with its longitudinal direction parallel to the axial direction of the winding core, A bar holding part that holds the tension bar so as to be movable along a predetermined movement path, It has, The state detection unit detects the position of the tension bar in the movement path, A tension adjustment method characterized by detecting the movement time, which is the time required for the tension bar to move from a preset first position to a second position different from the first position in the movement path, based on the position of the tension bar detected by the state detection unit, and changing the winding core rotation speed, which is the rotation speed at which the rotation drive unit rotates the winding core, based on the movement time.

9. A conveying device for transporting thin film sheets, A conveying unit that sends the sheet in a predetermined conveying direction so that the sheet passes through a predetermined position, A rotational drive unit that rotates the core around which the sheet is wound at a position upstream or downstream of the conveying unit in the conveying path through which the sheet is conveyed, A tension-applying unit is provided between the sheet roll, in which the sheet is wound around the core, and the conveying unit, which applies tension to the sheet. A state detection unit for detecting the state of the tension application unit, A control unit that controls the operation of the rotary drive unit and Equipped with, The tension-applying unit is, A tension bar, which is a rod-shaped member that contacts the sheet with its longitudinal direction parallel to the axial direction of the winding core, A bar holding part that holds the tension bar so as to be movable along a predetermined movement path, It has, The state detection unit detects the position of the tension bar in the movement path, The conveying device is characterized in that the control unit detects the movement time, which is the time required for the tension bar to move from a preset first position to a second position different from the first position in the movement path, based on the position of the tension bar detected by the state detection unit, and changes the core rotation speed, which is the rotation speed at which the rotation drive unit rotates the core, based on the movement time.

Images