Conveying device

Abstract

To provide a conveying device that can stably transport media. [Solution] The system comprises a media transport unit 23 for transporting a medium 15, a first drive unit 22 for driving the media transport unit 23, a media supply unit 29 for supplying the medium 15 toward the media transport unit 23, a second drive unit 28 for driving the media supply unit 29, a tension bar 31 positioned in the transport path between the media transport unit 23 and the media supply unit 29, swinging in a first direction D1 and a second direction D2 to apply tension to the transported medium 15, a third drive unit 38 for swinging the tension bar 31, a measuring unit 33 for measuring the output of the third drive unit 38 when moving the tension bar 31, and a control unit 26. The measuring unit 33 measures the first output of the third drive unit 38 when moving the tension bar 31 in the first direction D1 and the second output of the third drive unit 38 when moving the tension bar 31 in the second direction D2. The control unit 26 controls the third drive unit 38 based on the measurement results of the measuring unit 33.

Description

Technical Field

[0001] The present invention relates to a conveying device for conveying a medium.

Background Art

[0002] For example, as in Patent Document 1, there is a printer which is an example of a conveying device for conveying a medium. The printer includes a medium roll support shaft which is an example of a medium supply unit, a medium roll drive mechanism which is an example of a second drive unit, a supply bar member which is an example of a tension bar, a supply bar drive mechanism which is an example of a third drive unit, and a pair of conveying rollers which is an example of a medium conveying unit. The printer includes a load detection sensor and a control unit.

[0003] The medium roll support shaft supports the medium roll. The medium roll drive mechanism feeds out the medium from the medium roll by rotating the medium roll support shaft. The supply bar mechanism adjusts the tension applied to the medium by swinging as the medium is conveyed. The supply bar drive mechanism adjusts the driving force applied to the supply bar member. The pair of conveying rollers conveys the medium by rotating while sandwiching the medium. The load detection sensor detects the load applied to the pair of conveying rollers.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The control unit described in Patent Document 1 controls the driving force of the supply bar drive mechanism based on the load detected by the load detection sensor. The way the load is applied to the transport roller pair also changes depending on the direction in which the supply bar member moves. However, Patent Document 1 does not consider the case where the load changes depending on the direction in which the supply bar member moves. Therefore, there are difficulties in ensuring the stability of the transport of the medium. [Means for solving the problem]

[0006] A transport device that solves the above problems comprises a medium transport unit for transporting a medium, a first drive unit for driving the medium transport unit, a medium supply unit for supplying the medium to the medium transport unit, a second drive unit for driving the medium supply unit, a tension bar arranged in the transport path between the medium transport unit and the medium supply unit and swinging in a first direction and a second direction opposite to the first direction to apply tension to the transported medium, a third drive unit for swinging the tension bar, a measuring unit for measuring the output of the third drive unit when the tension bar is moved, and a control unit, wherein the measuring unit measures the first output of the third drive unit when the tension bar is moved in the first direction and the second output of the third drive unit when the tension bar is moved in the second direction, and the control unit controls the third drive unit based on the measurement results of the measuring unit. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic diagram of one embodiment of a printing apparatus equipped with a transport device. [Figure 2] Figure 2 shows graphs illustrating the first and second linear equations. [Modes for carrying out the invention]

[0008] [Embodiment] The printing apparatus equipped with a transport device will be described below with reference to the drawings. The printing apparatus is an inkjet printer that prints by ejecting ink, which is an example of a liquid, onto a medium such as paper, cloth, or vinyl. In the drawings, the direction of gravity is indicated by the Z axis, assuming that the printing apparatus 11 is placed on a horizontal plane, and the directions along the horizontal plane are indicated by the X and Y axes. The X, Y, and Z axes are orthogonal to each other.

[0009] <Printing device> As shown in Figure 1, the printing apparatus 11 may include a printing unit 12 and a transport device 13.

[0010] The printing unit 12 prints on the medium 15. The printing unit 12 may also include a liquid discharge unit 16 and a carriage 17. The liquid dispensing unit 16 has a plurality of nozzles 19. The liquid dispensing unit 16 is configured to dispense liquid from the plurality of nozzles 19.

[0011] The carriage 17 is equipped with a liquid dispensing unit 16. The carriage 17 is configured to scan the medium 15. The liquid dispensing unit 16 prints an image on the medium 15 by dispensing liquid while scanning. The liquid dispensing unit 16 prints on the surface of the medium 15. In this embodiment, the liquid dispensing unit 16 is a serial type that scans the medium 15. The liquid dispensing unit 16 may also be a line type that is provided in a length relative to the width of the medium 15.

[0012] <Conveying device> The conveying device 13 is configured to convey the medium 15. The conveying device 13 may include a support unit 21, a first drive unit 22, a medium conveying unit 23, a winding unit 24, a feeding mechanism 25, and a control unit 26.

[0013] The conveying device 13 may include a plurality of support parts 21. The support parts 21 are configured to support the medium 15. The support parts 21 are in contact with the back surface of the medium 15. The first drive unit 22 drives the medium transport unit 23. The first drive unit 22 is, for example, a motor.

[0014] The media transport unit 23 transports the media 15. The media transport unit 23 may transport the media 15 by rotating a pair of rollers that hold the media 15 between them. The media 15 is transported along the support unit 21 in the transport direction Dc. The media transport unit 23 may intermittently transport the media 15 in accordance with the timing of printing on the media 15 by the printing unit 12.

[0015] The winding unit 24 transports the printed medium 15 by winding it up. Specifically, the winding unit 24 pulls the roll-shaped medium 15 towards it by rotating it counterclockwise in Figure 1.

[0016] <Dispensing mechanism> The feeding mechanism 25 may include a second drive unit 28, a medium supply unit 29, a driven roller 30, a tension bar 31, and a swinging unit 32. The feeding mechanism 25 may also include a measuring unit 33 and a detection unit 34.

[0017] The second drive unit 28 drives the medium supply unit 29. The second drive unit 28 is, for example, a motor. The media supply unit 29 supplies the media 15 to the media transport unit 23. The media supply unit 29 feeds out a long piece of media 15. The media supply unit 29 rotatably supports the rolled-up media 15 before printing. The media supply unit 29 transports the media 15 by rotating. Specifically, the media supply unit 29 unwinds the rolled-up media 15 by rotating it counterclockwise in Figure 1. The unwinded media 15 is wound onto the driven roller 30, tension bar 31, and media transport unit 23 in that order.

[0018] The driven roller 30 may rotate in a manner driven by the medium 15 being conveyed. The driven roller 30 may slide against the medium 15. The driven roller 30 may be in contact with the back surface of the medium 15.

[0019] The tension bar 31 is disposed in the conveyance path between the medium conveyance unit 23 and the medium supply unit 29. The tension bar 31 swings in the first direction D1 and the second direction D2. The second direction D2 is the direction opposite to the first direction D1. The first direction D1 in the present embodiment is the upward direction. The second direction D2 in the present embodiment is the downward direction. The tension bar 31 may be rotatable bidirectionally between the lower position Pd and the upper position Pu shown by the two-dot chain line in FIG. 1. Rotation means rotation around an axis, and rotation with a rotatable angle of less than 360 degrees. The tension bar 31 may contact the surface of the medium 15. The tension bar 31 applies tension to the conveyed medium 15.

[0020] The swing unit 32 may include an arm unit 36, a rotation shaft 37, and a third drive unit 38. The swing unit 32 may include a pair of arm units 36. The pair of arm units 36 may support both ends of the tension bar 31. The arm unit 36 supports the tension bar 31. The arm unit 36 may support the tension bar 31 at its tip. The arm unit 36 may be fixed to the rotation shaft 37. The arm unit 36 is rotatable around the rotation shaft 37. The arm unit 36 displaces the tension bar 31 by rotating.

[0021] The rotation shaft 37 may rotate the arm unit 36. The rotation shaft may be segmented. The rotation shaft 37 of one arm unit 36 and the rotation shaft 37 of the other arm unit 36 may be integrated, or a pair of rotation shafts 37 may be provided coaxially. The rotation shaft 37 may move the tension bar 31 in the first direction D1 by rotating forward. The rotation shaft 37 may move the tension bar 3 in the second direction D2 by rotating backward.

[0022] The third drive unit 38 swings the tension bar 31. Specifically, the third drive unit 38 drives the rotation shaft 37. The third drive unit 38 swings the tension bar 31 by rotating the rotation shaft 37 and the arm unit 36. The third drive unit 38 is, for example, a motor.

[0023] The measuring unit 33 measures the output of the third drive unit 38 when the tension bar 31 is moved. The measuring unit 33 may also measure the current value when the third drive unit 38 is being driven, for example. The measuring unit 33 may also measure the voltage value when the third drive unit 38 is being driven, for example.

[0024] The detection unit 34 may also detect the speed at which the tension bar 31 moves, the direction in which the tension bar 31 moves, and the position of the tension bar 31. The detection unit 34 may directly or indirectly detect the speed, direction, and position of the tension bar 31.

[0025] The detection unit 34 in this embodiment is a rotary encoder. The scale of the rotary encoder may be provided on the rotating shaft 37. The control unit 26 may calculate the speed, direction, and position of the tension bar 31 based on the rotational speed and direction of rotation of the rotating shaft 37.

[0026] Specifically, the detection unit 34 may output A-phase and B-phase pulse signals that are in different phases from each other. The phases of the two types of pulse signals may differ by, for example, 90 degrees. For example, when the pivot shaft 37 rotates forward, the A-phase leads the B-phase. When the pivot shaft 37 rotates in reverse, the B-phase leads the A-phase. Therefore, the control unit 26 may determine the rotation direction of the pivot shaft 37 based on whether the A-phase leads or lags behind the B-phase. The control unit 26 may calculate the rotation speed of the pivot shaft 37 based on the number of pulses per unit time. The control unit 26 may calculate the position of the tension bar 31 from the amount and direction of rotation of the pivot shaft 37, for example, with respect to the lower position Pd.

[0027] The control unit 26 comprehensively controls the driving of each mechanism in the transport device 13 and controls the various operations performed by the transport device 13. The control unit 26 may also control the driving of each mechanism and various operations in the printing device 11.

[0028] The control unit 26 may be configured as a circuit including α: one or more processors that perform various processes according to a computer program, β: one or more dedicated hardware circuits that perform at least some of the various processes, or γ: a combination thereof. The hardware circuit is, for example, an application-specific integrated circuit. The processor includes a CPU and memory such as RAM and ROM, and the memory stores program code or instructions configured to cause the CPU to perform the processes. Memory, or computer-readable media, includes any readable media that can be accessed by a general-purpose or dedicated computer.

[0029] <Measurement operation> The control unit 26 performs a measurement operation before printing on the medium 15. The measurement operation may be performed by the manufacturer before the printing device 11 is shipped. The measurement operation may also be performed by the user before printing. The measurement operation is performed without the medium 15 being wrapped around the tension bar 31. That is, the tension bar 31 does not come into contact with the medium 15 during the measurement operation.

[0030] When the measurement operation starts, the control unit 26 positions the tension bar 31 to the lower position Pd. The control unit 26 may also position the tension bar 31 to the lower position Pd by driving the third drive unit 38 in the reverse direction for a certain period of time. Subsequently, the control unit 26 may drive the third drive unit 38 to move the tension bar 31 back and forth twice. The measuring unit 33 measures the first output of the third drive unit 38 when the tension bar 31 is moved in the first direction D1, and the second output of the third drive unit 38 when the tension bar 31 is moved in the second direction D2.

[0031] Specifically, the control unit 26 drives the third drive unit 38 in the forward direction at high speed, and causes the measuring unit 33 to measure the output of the third drive unit 38. That is, the control unit 26 moves the tension bar 31 in a first direction D1 at a first speed V1. The measurement result of the measuring unit 33 at this time is defined as the first high-speed output TiH1. The first high-speed output TiH1 is an example of a first output. In other words, the first high-speed output TiH1 is the first output of the third drive unit 38 when the tension bar 31 is moved in a first direction D1 at a first speed V1. The control unit 26 may also move the tension bar 31 to an upper position Pu. The first high-speed output TiH1 may be the average value from the start of driving the third drive unit 38 until the stop of driving.

[0032] Next, the control unit 26 drives the third drive unit 38 in reverse at high speed and has the measuring unit 33 measure the output of the third drive unit 38. That is, the control unit 26 moves the tension bar 31 in the second direction D2 at a third speed V3. The measurement result of the measuring unit 33 at this time is defined as the second high-speed output TiH2. The second high-speed output TiH2 is an example of a second output. In other words, the second high-speed output TiH2 is the second output of the third drive unit 38 when the tension bar 31 is moved in the second direction D2 at a third speed V3. The control unit 26 may also move the tension bar 31 to the lower position Pd. The second high-speed output TiH2 may also be the average value from when the third drive unit 38 is started to when it is stopped.

[0033] Next, the control unit 26 drives the third drive unit 38 in the forward direction at a low speed, and has the measuring unit 33 measure the output of the third drive unit 38. That is, the control unit 26 moves the tension bar 31 in the first direction D1 at a second speed V2. The measurement result of the measuring unit 33 at this time is defined as the first low-speed output TiL1. The second speed V2 is slower than the first speed V1. The first low-speed output TiL1 is an example of the first output. In other words, the first low-speed output TiL1 is the first output of the third drive unit 38 when the tension bar 31 is moved in the first direction D1 at a second speed V2. The first output may include the first high-speed output TiH1 and the first low-speed output TiL1. The control unit 26 may move the tension bar 31 to the upper position Pu. The first low-speed output TiL1 may be the average value from the start of driving the third drive unit 38 until the stop of driving.

[0034] The control unit 26 drives the third drive unit 38 in reverse at a low speed and has the measuring unit 33 measure the output of the third drive unit 38. That is, the control unit 26 moves the tension bar 31 in the second direction D2 at a fourth speed V4. The measurement result of the measuring unit 33 at this time is defined as the second low-speed output TiL2. The fourth speed V4 is slower than the third speed V3. The second low-speed output TiL2 is an example of a second output. In other words, the second low-speed output TiL2 is the second output of the third drive unit 38 when the tension bar 31 is moved in the second direction D2 at a fourth speed V4. The second output may include a second high-speed output TiH2 and a second low-speed output TiL2. The control unit 26 may move the tension bar 31 to a lower position Pd. The second low-speed output TiL2 may be the average value from the start of driving the third drive unit 38 until the stop of driving.

[0035] As shown in Figure 2, the control unit 26 creates equation (1), an example of a first-order linear equation, based on the measurement results of the measurement unit 33. In Figure 2, the graph of equation (1) is shown with the velocity moving in the first direction D1 as positive. The first-order linear equation is based on the first velocity V1, the second velocity V2, the first high-speed output TiH1, and the first low-speed output TiL1. Specifically, the control unit 26 determines coefficient a based on equation (2). The control unit 26 determines coefficient b based on equation (3). The control unit 26 reflects coefficients a and b into equation (1).

[0036]

number

[0037] The control unit 26 creates equation (4), an example of a second-order linear equation, based on the measurement results from the measurement unit 33. Figure 2 shows a graph of equation (4) with the velocity moving in the second direction D2 being negative. The second-order linear equation is based on the third velocity V3, the fourth velocity V4, the second high-speed output TiH2, and the second low-speed output TiL2. Specifically, the control unit 26 determines the coefficient a' based on equation (5). The control unit 26 determines the coefficient b' based on equation (6). The control unit 26 reflects the coefficients a' and b' into equation (4).

[0038]

number

[0039] <Transportation Operation> As shown in Figure 1, the conveying device 13 conveys the medium 15 from the dispensing mechanism 25 to the winding section 24. When the medium conveying section 23 conveys the medium 15, the tension on the medium 15 upstream of the medium conveying section 23 in the conveying direction Dc increases. As a result, the medium 15 pushes up the tension bar 31. That is, the tension bar 31 moves in the first direction D1.

[0040] The detection unit 34 detects the speed, direction, and position of the tension bar 31 as it moves. The control unit 26 drives the second drive unit 28 according to the position of the tension bar 31. When the tension bar 31 is on the first direction D1 side of the reference position Pr shown by the solid line in Figure 1, the control unit 26 may rotate the medium supply unit 29 counterclockwise in Figure 1. That is, when the tension bar 31 is above the reference position Pr, the medium 15 is supplied from the medium supply unit 29. As a result, the tension bar 31 moves downward due to its own weight. The tension bar 31 moves in the second direction D2.

[0041] When the tension bar 31 is located on the second direction D2 side of the reference position Pr, the control unit 26 may rotate the medium supply unit 29 clockwise in Figure 1. That is, when the tension bar 31 is below the reference position Pr, the medium supply unit 29 winds up the medium 15. Therefore, the tension bar 31 moves in the first direction D1.

[0042] <Auxiliary actions> The control unit 26 performs auxiliary operations in parallel with the transport operation. When the detection unit 34 detects the movement of the tension bar 31, the control unit 26 performs auxiliary operations.

[0043] When the tension bar 31 moves in the first direction D1, the control unit 26 controls the third drive unit 38 using equation (1), which is a first-order linear equation. The control unit 26 calculates y by substituting the speed detected by the detection unit 34 for x in the first-order linear equation. This y is the output of the third drive unit 38 required to move the tension bar 31 in the first direction D1 at the speed detected by the detection unit 34. The control unit 26 drives the third drive unit 38 with an output obtained by subtracting the tension required for transporting the medium 15 from the calculated y.

[0044] When the tension bar 31 moves in the second direction D2, the control unit 26 controls the third drive unit 38 using equation (4), which is a second linear equation. The control unit 26 calculates y by substituting the speed detected by the detection unit 34 for x in the second linear equation. This y is the output of the third drive unit 38 required to move the tension bar 31 in the second direction D2 at the speed detected by the detection unit 34. The control unit 26 drives the third drive unit 38 with an output obtained by subtracting the tension required for transporting the medium 15 from the calculated y.

[0045] <Operation of this embodiment> The operation of this embodiment will now be described. The control unit 26 controls the third drive unit 38 based on the measurement results of the measuring unit 33. When the conveyed medium 15 moves the tension bar 31 in the first direction D1, the control unit 26 causes the third drive unit 38 to assist in the movement of the tension bar 31 based on the first linear equation and the speed at which the tension bar 31 moves. When the conveyed medium 15 moves the tension bar 31 in the second direction D2, the control unit 26 causes the third drive unit 38 to assist in the movement of the tension bar 31 based on the second linear equation and the speed at which the tension bar 31 moves.

[0046] <Effects of this embodiment> The effects of this embodiment will now be explained. (1-1) The control unit 26 controls the third drive unit 38 based on the first output when the tension bar 31 is moved in the first direction D1 and the second output when the tension bar 31 is moved in the second direction D2. Therefore, the third drive unit 38 is controlled taking into account the direction in which the tension bar 31 moves, so that the medium 15 can be transported stably.

[0047] (1-2) The load that moves the tension bar 31 changes not only in the direction of movement but also in the speed of movement. In this respect, the measuring unit 33 measures by changing the speed at which the tension bar 31 is moved. Therefore, the reliability of the first and second linear equations can be improved.

[0048] (1-3) When the tension bar 31 moves in the first direction D1, the control unit 26 controls the third drive unit 38 according to the first linear equation and the speed at which the tension bar 31 moves. When the tension bar 31 moves in the second direction D2, the control unit 26 controls the third drive unit 38 according to the second linear equation and the speed at which the tension bar 31 moves. In other words, the control unit 26 causes the third drive unit 38 to assist in the movement of the tension bar 31 according to the direction and speed at which the tension bar 31 moves. As a result, the medium 15 can be conveyed more stably.

[0049] (1-4) The arm portion 36 supports the tension bar 31. The arm portion 36 rotates in conjunction with the rotation of the pivot shaft 37. Therefore, by driving the pivot shaft 37 with the third drive unit 38, the tension bar 31 can be easily swung.

[0050] (1-5) Gravity acts on the tension bar 31. Therefore, for example, when the tension bar 31 is swung vertically, the difference between the load when moving in the first direction D1 and the load when moving in the second direction D2 tends to be larger than when it is swung horizontally. In this regard, the control unit 26 drives the third drive unit 38 taking into consideration the direction in which the tension bar 31 is moved. Therefore, even when the tension bar 31 is swung upwards and downwards, the movement of the tension bar 31 can be appropriately assisted.

[0051] (1-6) The load required to rotate the media supply unit 29 varies depending on the amount of media 15 supported by the media supply unit 29. The media 15 wound in a roll is also called a roll body. For example, a roll body with a large diameter takes longer to start and stop than a roll body with a small diameter. When using a large roll body, it is difficult to feed the media 15 with the appropriate tension. In this regard, the media transport unit 23 is equipped with a tension bar 31 provided between the media supply unit 29 and the media transport unit 23. Therefore, the tension applied to the media 15 can be quickly adjusted.

[0052] (1-7) The output of the third drive unit 38 when moving the tension bar 31 may change depending on, for example, the period of time the conveying device 13 is used or the environment in which the conveying device 13 is used. In this regard, the conveying device 13 is equipped with a measuring unit 33. By having the measuring unit 33 measure the first output and the second output before conveying the medium 15, the third drive unit 38 can be controlled with greater precision.

[0053] [Example of changes] This embodiment can be implemented with the following modifications. This embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0054] The detection unit 34 may separately include a speed detection unit for detecting the speed at which the tension bar 31 moves, a direction detection unit for detecting the direction in which the tension bar 31 moves, and a position detection unit for detecting the position of the tension bar 31.

[0055] The tension bar 31 may be located in the transport path between the media transport unit 23 and the winding unit 24. The tension bar 31 may apply tension to the printed media 15. The oscillating unit 32 may assist in the movement of the tension bar 31 located downstream of the printing unit 12.

[0056] The control unit 26 may acquire measurement results measured by a measuring unit 33, which is a separate device from the conveying device 13, and create a first-order and a second-order equation. The first-order and the second-order equation may be created by a separate device from the conveying device 13. The control unit 26 may acquire the first-order and the second-order equation created by the separate device.

[0057] The tension bar 31 may move back and forth in a straight line. The first direction D1 and the second direction D2 may be directions along the horizontal plane. The first direction D1 may be a vertical direction perpendicular to the horizontal plane, or it may be a direction that intersects the horizontal plane at an angle.

[0058] During the measurement operation, the control unit 26 may move the tension bar 31 back and forth once. The control unit 26 may change the speed of the tension bar 31 as it moves in the first direction D1 or the second direction D2. For example, the control unit 26 may move the tension bar 31 from the lower position Pd to the reference position Pr at a second speed V2, and then move it from the reference position Pr to the upper position Pu at a first speed V1. The control unit 26 may move the tension bar 31 from the upper position Pu to the reference position Pr at a fourth speed V4, and then move it from the reference position Pr to the lower position Pd at a third speed V3.

[0059] During the measurement operation, the control unit 26 may change the speed of the tension bar 31 to make it move back and forth three or more times. The control unit 26 may create an equation to assist the tension bar 31 moving in the first direction D1 from three or more combinations of speed and the first output. The control unit 26 may create an equation to assist the tension bar 31 moving in the second direction D2 from three or more combinations of speed and the second output.

[0060] The conveying device 13 may be provided in a device different from the printing device 11. The conveying device 13 may be configured without a winding unit 24. The conveying device 13 may supply the medium 15 to other devices. For example, the conveying device 13 may supply the medium 15 to a cutting device that cuts the medium 15.

[0061] The printing device 11 is not limited to an inkjet printer; it may also be a laser printer, thermal printer, dot matrix printer, digital printing press, etc. The printing device 11 is a device that prints characters, pictures, photographs, and other images by attaching liquids such as ink or fluids such as toner to a medium 15, and may be a serial printer, lateral printer, line printer, page printer, etc. The printing device 11 may also be an offset printing device, a textile printing device, etc.

[0062] [Definition] As used herein, the expression "at least one" means "one or more" of the desired options. For example, as used herein, if there are two options, the expression "at least one" means "only one option" or "both of the two options." As another example, as used herein, the expression "at least one" means "only one option," "a combination of two arbitrary options," or "a combination of three or more arbitrary options" if there are three or more options.

[0063] [Note] The technical concepts and their effects that can be understood from the embodiments and modifications described above are described below.

[0064] [1] The transport device comprises a medium transport unit for transporting a medium, a first drive unit for driving the medium transport unit, a medium supply unit for supplying the medium to the medium transport unit, a second drive unit for driving the medium supply unit, a tension bar positioned in the transport path between the medium transport unit and the medium supply unit and swinging in a first direction and a second direction opposite to the first direction to apply tension to the transported medium, a third drive unit for swinging the tension bar, a measuring unit for measuring the output of the third drive unit when the tension bar is moved, and a control unit, wherein the measuring unit measures the first output of the third drive unit when the tension bar is moved in the first direction and the second output of the third drive unit when the tension bar is moved in the second direction, and the control unit controls the third drive unit based on the measurement results of the measuring unit.

[0065] In this configuration, the control unit controls the third drive unit based on a first output when the tension bar is moved in a first direction and a second output when the tension bar is moved in a second direction. Therefore, because the third drive unit is controlled considering the direction in which the tension bar moves, the medium can be transported stably.

[0066] [2] In the conveying device described in [1] above, the first output includes a first high-speed output when the tension bar is moved in the first direction at a first speed and a first low-speed output when the tension bar is moved in the first direction at a second speed slower than the first speed, the second output includes a second high-speed output when the tension bar is moved in the second direction at a third speed and a second low-speed output when the tension bar is moved in the second direction at a fourth speed slower than the third speed, and the control unit may control the third drive unit using a first linear equation based on the first speed, the second speed, the first high-speed output and the first low-speed output and a second linear equation based on the third speed, the fourth speed, the second high-speed output and the second low-speed output.

[0067] The load that moves the tension bar changes not only with the direction of movement but also with the speed of movement. In this configuration, the measuring unit measures by changing the speed at which the tension bar is moved. Therefore, the reliability of the first and second linear equations can be improved.

[0068] [3] In the conveying device described in [2] above, the control unit may cause the third drive unit to assist the movement of the tension bar based on the first linear equation and the speed at which the tension bar moves when the conveyed medium moves the tension bar in the first direction, and may cause the third drive unit to assist the movement of the tension bar based on the second linear equation and the speed at which the tension bar moves when the conveyed medium moves the tension bar in the second direction.

[0069] In this configuration, when the tension bar moves in the first direction, the control unit controls the third drive unit according to the first linear equation and the speed at which the tension bar moves. When the tension bar moves in the second direction, the control unit controls the third drive unit according to the second linear equation and the speed at which the tension bar moves. In other words, the control unit causes the third drive unit to assist the movement of the tension bar according to the direction and speed at which the tension bar moves. Therefore, the medium can be transported more stably.

[0070] [4] Any one of the conveying devices described in [1] to [3] above further comprises an arm portion that supports the tension bar and a pivot shaft that rotates the arm portion, and the third drive unit may drive the pivot shaft.

[0071] In this configuration, the arm supports the tension bar. The arm rotates in conjunction with the rotation of the pivot axis. Therefore, by driving the pivot axis with the third drive unit, the tension bar can be easily oscillated.

[0072] [5] In any one of the conveying devices described in [1] to [4] above, the first direction may be upward and the second direction may be downward. Gravity acts on the tension bar. Therefore, for example, when the tension bar is oscillated vertically, the difference between the load when moving in the first direction and the load when moving in the second direction tends to be larger than when it is oscillated horizontally. In this configuration, the control unit drives the third drive unit considering the direction in which the tension bar is moved. Therefore, even when the tension bar is oscillated upwards and downwards, the movement of the tension bar can be appropriately assisted. [Explanation of symbols]

[0073] 11…Printing device, 12…Printing unit, 13…Conveying device, 15…Media, 16…Liquid discharge unit, 17…Carriage, 19…Nozzle, 21…Support unit, 22…First drive unit, 23…Media conveying unit, 24…Winding unit, 25…Feeding mechanism, 26…Control unit, 28…Second drive unit, 29…Media supply unit, 30…Driven roller, 31…Tension bar, 32…Oscillating unit, 33…Measurement unit, 34…Detection unit, 36…Arm unit, 37…Rotating shaft, 38…Third drive unit, D1…First direction, D2…Second direction, Dc…Conveying direction, Pd…Downward position, Pr…Reference position, Pu…Upward position.

Claims

1. A media transport unit that transports media, A first drive unit that drives the media transport unit, A media supply unit that supplies the media toward the media transport unit, A second drive unit that drives the media supply unit, A tension bar is positioned in the transport path between the medium transport unit and the medium supply unit, swings in a first direction and a second direction opposite to the first direction, and applies tension to the transported medium. A third drive unit that swings the tension bar, A measuring unit for measuring the output of the third drive unit when the tension bar is moved, Control unit and Equipped with, The aforementioned measuring unit is The first output of the third drive unit when the tension bar is moved in the first direction, The second output of the third drive unit when the tension bar is moved in the second direction, Measure, The conveying device is characterized in that the control unit controls the third drive unit based on the measurement results of the measurement unit.

2. The first output is, The first high-speed output when the tension bar is moved in the first direction at a first speed, The first low-speed output when the tension bar is moved in the first direction at a second speed slower than the first speed, Includes, The second output is, The second high-speed output when the tension bar is moved in the second direction at a third speed, The second low-speed output when the tension bar is moved in the second direction at a fourth speed slower than the third speed, Includes, The control unit, A first linear equation based on the first speed, the second speed, the first high-speed output, and the first low-speed output, A second linear equation based on the third speed, the fourth speed, the second high-speed output, and the second low-speed output, The conveying device according to claim 1, characterized in that the third drive unit is controlled using the method described above.

3. The control unit, When the transported medium moves the tension bar in the first direction, the third drive unit assists the movement of the tension bar based on the first linear equation and the speed at which the tension bar moves. The conveying device according to claim 2, characterized in that when the conveyed medium moves the tension bar in the second direction, the third drive unit assists the movement of the tension bar based on the second linear equation and the speed at which the tension bar moves.

4. The arm portion that supports the tension bar, The pivot shaft that rotates the aforementioned arm portion, Furthermore, The conveying device according to claim 1, characterized in that the third drive unit drives the pivot shaft.

5. The conveying device according to any one of claims 1 to 4, characterized in that the first direction is upward and the second direction is downward.

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