Conveyance device, printer, control method, and program

Abstract

Provided are a conveyance device, a printer, a control method, and a program which are capable of reducing time and effort in adjusting tension applied to a medium.　The printer has a delivery part, a winding part, and a conveyance part. The printer performs an initial operation (S4, S6). The printer measures the amount of elongation of fabric in the initial operation on the basis of a rotational position detected by an encoder of the conveyance part. The printer measures the tension applied to the fabric in the initial operation on the basis of the displacement of a roller detected by a displacement sensor and the elastic modulus of a compression coil spring. The printer determines an optimal value of the tension at the time of conveying the fabric on the basis of the relationship between the elongation amount of the fabric and the tension applied to the fabric measured in the initial operation (S9).

Description

Conveyance device, printer, control method, and program

[0001] The present invention relates to a conveying device, a printer, a control method, and a program.

[0002] Patent Literature 1 discloses a load adjustment mechanism capable of adjusting the tension applied to a fabric, which is a printing medium. The load adjustment mechanism includes a tension bar that is disposed in the fabric transport path and presses against the fabric. The tension bar is supported by supports disposed on the left and right sides of the printing device main body. The supports support the tension bar so that it can be raised and lowered. One of the supports is provided with a weight that acts in a direction to reduce the weight of the tension bar, and a first connecting member that connects the weight to one end of the tension bar so that they move together in the vertical direction. The other support is provided with an adjustment member and a second connecting member that connects the adjustment member to the other end of the tension bar so that they move together in the vertical direction. The adjustment member can be selectively coupled to multiple weights. The user selects a weight from the multiple weights according to the desired tension load and couples the selected weight to the adjustment member to adjust the tension.

[0003] JP 2016-190689 A

[0004] The optimum tension varies depending on the type of fabric (such as the type of fiber or weave). However, with the load adjustment mechanism of Patent Document 1, the user must select an appropriate weight to adjust the optimum tension applied to the fabric. Therefore, with the load adjustment mechanism, adjusting the tension is time-consuming.

[0005] An object of the present invention is to provide a conveying device, a printer, a control method, and a program that can reduce the effort required to adjust the tension applied to the medium.

[0006] A conveying device according to a first aspect of the present invention comprises a feed section that feeds out a medium, a take-up section that takes up the medium fed out by the feed section, a conveying section that is provided on a conveying path between the feed section and the take-up section and conveys the medium, a tension detection section that detects the magnitude of tension applied to the medium conveyed between the feed section and the take-up section, a conveying amount detection section that detects the conveying amount of the medium conveyed between the feed section and the take-up section, and a control section, wherein the control section performs an initial operation process that conveys the medium by driving at least one of the feed section, the take-up section, and the conveying section, and a determination process that determines an optimal value of the tension based on the magnitude of the tension detected by the tension detection section and the conveying amount detected by the conveying amount detection section during the execution of the initial operation process.

[0007] The conveying device according to the first aspect performs an initial operation to convey the medium by driving at least one of the delivery unit, the winding unit, and the conveying unit, and determines the tension to be applied to the medium based on the tension and conveyance amount detected during the initial operation. In this way, the conveying device automatically determines the tension to be applied to the medium by performing the initial operation. Therefore, the conveying device can reduce the effort required to adjust the tension applied to the medium compared to when the tension is adjusted manually by a user.

[0008] A printer according to a second aspect of the present invention is characterized by comprising the conveying device described in claim 1 and a printing unit that prints on the medium conveyed between the delivery unit and the winding unit.

[0009] A control method according to a third aspect of the present invention is a control method for a conveying device comprising a feed section that feeds out a medium, a take-up section that takes up the medium fed out by the feed section, a conveying section that is provided on a conveying path between the feed section and the take-up section and conveys the medium, a tension detection section that detects the magnitude of tension applied to the medium conveyed between the feed section and the take-up section, and a conveying amount detection section that detects the conveying amount of the medium conveyed between the feed section and the take-up section, and is characterized in that the control method includes an initial operation step of driving at least one of the feed section, the take-up section, and the conveying section to convey the medium, and a determination step of determining an optimal value of the tension based on the magnitude of the tension detected by the tension detection section and the conveying amount detected by the conveying amount detection section during the execution of the initial operation step.

[0010] A fourth aspect of the present invention provides a program for execution by a computer that controls a conveying device including a feed section that feeds out a medium, a take-up section that takes up the medium fed out by the feed section, a conveying section that is provided on a conveying path between the feed section and the take-up section and conveys the medium, a tension detection section that detects the magnitude of tension applied to the medium conveyed between the feed section and the take-up section, and a conveying amount detection section that detects the conveying amount of the medium conveyed between the feed section and the take-up section, and is characterized in that the program causes the computer to execute an initial operation step of driving at least one of the feed section, the take-up section, and the conveying section to convey the medium, and a determination step of determining an optimal value of the tension based on the magnitude of the tension detected by the tension detection section and the conveying amount detected by the conveying amount detection section during execution of the initial operation step.

[0011] The printer according to the second aspect, the control method according to the third aspect, and the program according to the fourth aspect have the same effects as the conveying device according to the first aspect.

[0012] 1 is a diagram showing the configuration of a printer 100 and a conveying device 1. FIG. 2 is a block diagram showing the electrical configuration of the printer 100. FIG. 3 is a conceptual diagram of a table 91. FIG. 4 is a diagram showing the relationship between conveyance amount and tension in an initial operation. FIG. 5 is a flowchart of main processing. FIG. 6 is a conceptual diagram of a table 92.

[0013] An embodiment of the present invention will be described below with reference to the drawings. The drawings are used to explain technical features that can be adopted by the present invention. In other words, the configurations and the like shown in the drawings are merely illustrative examples and are not intended to limit the present invention.

[0014] <Configuration of Printer 100> The configuration of the printer 100 will be described with reference to Fig. 1. Hereinafter, the front side, rear side, right side, left side, top side, and bottom side of the paper in Fig. 1 will be referred to as the left side, right side, front side, rear side, top side, and bottom side of the printer 100, respectively. Note that in this embodiment, the up-down direction is used for convenience of explanation and is not limited to the vertical direction.

[0015] The printer 100 shown in FIG. 1 prints on a long print medium. In this embodiment, the print medium is fabric M, but it may be, for example, paper, plastic film, etc. The fabric M may be, for example, woven fabric, knitted fabric, nonwoven fabric, etc. The printer 100 has a conveying device 1, a housing 2, a platen 3, and a printing unit 4. The conveying device 1 conveys the fabric M inside the housing 2. In this embodiment, the conveying path R of the fabric M is entirely inside the housing 2, but part or all of the conveying path R of the fabric M may be outside the housing 2. Details of the conveying device 1 will be described later.

[0016] The housing 2 houses the conveying device 1, a platen 3, and a printing unit 4. The platen 3 is housed in the upper part of the housing 2 and is located between the center of the housing 2 in the front-to-rear direction and the front end of the housing 2. The platen 3 is a plate that has a thickness in the vertical direction. The platen 3 is provided on the conveying path R of the fabric M conveyed by the conveying device 1 and supports the fabric M from below. The printing unit 4 is located above the platen 3. In this embodiment, the printing unit 4 is an inkjet head that performs printing by ejecting ink toward the fabric M supported by the platen 3. The printing unit 4 may be, for example, a thermal head that prints by thermal transfer, or an electrophotographic printing system that uses toner.

[0017] <Configuration of conveying device 1> The conveying device 1 has a let-off section 10, a winding section 20, a conveying section 50, dancer rollers 6 and 7, and rollers 81 to 84. The let-off section 10 is housed in the lower rear part of the housing 2. The let-off section 10 has a shaft 12 and a let-off motor 13 (see Figure 2). The shaft 12 is rod-shaped extending in the left-right direction and is rotatable around its axis. The shaft 12 holds a roll 11 around which the fabric M is wound. The let-off motor 13 rotates the shaft 12. The fabric M is let out from the let-off section 10 by driving the let-off motor 13. In this embodiment, "feeding out" does not only mean that the feed-out unit 10 is connected to a drive source such as the feed-out motor 13 and actively "feeds out" the fabric M, but also means that the feed-out unit 10 is not connected to a drive source and "feeds out" the fabric M by rotating freely due to winding by the winding unit 20.

[0018] The winding unit 20 is housed in the lower front part of the housing 2. The winding unit 20 has a shaft 22 and a winding motor 23 (see Figure 2). The shaft 22 is rod-shaped extending in the left-right direction and is rotatable around its axis. The shaft 22 holds a roll 21 around which the fabric M is wound. The winding motor 23 rotates the shaft 22. The fabric M sent out from the sending unit 10 is wound onto the winding unit 20 by driving the winding motor 23. Hereinafter, the path of the fabric M transported from the sending unit 10 to the winding unit 20 will be referred to as the transport path R. In this embodiment, "winding" does not only mean that the winding unit 20 is connected to a driving source such as the winding motor 23 and actively "winds" the fabric M, but also means that the winding unit 20 is not connected to a driving source and "winds" the fabric M by rotating freely due to the feeding by the feeding unit 10.

[0019] The conveying unit 50 is provided on the conveying path R of the fabric M. The conveying unit 50 is housed in the upper part of the housing 2 and is located behind the platen 3. The conveying unit 50 has a conveying roller 51, a pinch roller 52, and a conveying motor 53 (see Figure 2). The conveying unit 50 and the platen 3 are at approximately the same position in the vertical direction. The conveying roller 51 and the pinch roller 52 are cylindrical with axes extending in the left-right direction and are rotatable around the axes. The pinch roller 52 faces the conveying roller 51 in the vertical direction. The conveying motor 53 rotates the conveying roller 51. The conveying unit 50 performs nip conveyance by sandwiching the fabric M between the conveying roller 51 and the pinch roller 52.

[0020] The dancer roller 6 is located between the feed unit 10 and the conveying unit 50 in the front-rear direction. The dancer roller 6 has a support unit 61, a compression coil spring 62, a roller 63, and a displacement sensor 64 (see FIG. 2 ). The support unit 61 is a plate that has a thickness in the vertical direction and is fixed to the housing 2. The compression coil spring 62 extends in the vertical direction. The upper end of the compression coil spring 62 is connected to the support unit 61, and the lower end of the compression coil spring 62 is connected to the roller 63.

[0021] The roller 63 is provided on the transport path R of the fabric M. The roller 63 is cylindrical with an axis extending in the left-right direction and is rotatable around the axis. The roller 63 is movable in the up-down direction and is constantly biased downward by a compression coil spring 62. The displacement sensor 64 detects the vertical displacement of the roller 63 from a reference position. In this embodiment, the reference position of the roller 63 is the vertical position of the roller 63 when no tension is applied to the fabric M.

[0022] The dancer roller 7 is located between the platen 3 and the winding unit 20 in the front-to-rear direction. The dancer roller 7 has a support portion 71, a compression coil spring 72, a roller 73, and a displacement sensor 74 (see FIG. 2 ). The support portion 71 is a plate that has a thickness in the vertical direction and is fixed to the housing 2. The compression coil spring 72 extends in the vertical direction. The upper end of the compression coil spring 72 is connected to the support portion 71, and the lower end of the compression coil spring 72 is connected to the roller 73.

[0023] The roller 73 is provided on the transport path R of the fabric M. The roller 73 is cylindrical with an axis extending in the left-right direction and is rotatable around the axis. The roller 73 is movable in the up-down direction and is constantly biased downward by a compression coil spring 72. The displacement sensor 74 detects the vertical displacement of the roller 73 from a reference position. In this embodiment, the reference position of the roller 73 is the vertical position of the roller 73 when no tension is applied to the fabric M.

[0024] Rollers 81 to 84 are provided on the transport path R of the fabric M. Rollers 81 to 84 are cylindrical with axes extending in the left-right direction and are rotatable around their axes. Roller 81 is provided above and in front of dancer roller 6 and below and behind transport section 50. Roller 82 is provided above and behind roller 81, and is positioned lower than transport roller 51 in the vertical direction. Roller 84 is provided above and behind dancer roller 7 and below and in front of platen 3. Roller 83 is provided above and in front of roller 84, and is at approximately the same position as platen 3 in the vertical direction.

[0025] <Conveyance of fabric M by conveying device 1> The conveying device 1 conveys the fabric M by driving the let-off section 10, the winding section 20, and the conveying section 50. In the conveying device 1, the fabric M is let-off from the roll 11 of the let-off section 10 and wound onto the roll 21 of the winding section 20. More specifically, when the fabric M is let-off from the let-off section 10, the fabric M is conveyed in the following order: let-off section 10, roller 63, rollers 81 and 82, the conveying section 50, the platen 3, rollers 83 and 84, roller 73, and the winding section 20.

[0026] The printer 100 uses the printing unit 4 to print on the fabric M transported between the delivery unit 10 and the winding unit 20. Hereinafter, the direction in which the fabric M is transported from the delivery unit 10 to the winding unit 20 along the transport path R will be referred to as the forward direction F. The direction opposite to the forward direction F, in which the fabric M is wound from the winding unit 20 onto the delivery unit 10 along the transport path R, will be referred to as the reverse direction B. The section of the transport path R from the delivery unit 10 to the transport unit 50 will be referred to as section R1. The section of the transport path R from the transport unit 50 to the winding unit 20 will be referred to as section R2.

[0027] The fabric M transported through section R1 is subjected to tension by the let-off section 10, the conveying section 50, the dancer roller 6, etc. In this embodiment, the magnitude of the tension applied to the fabric M transported through section R1 is determined by the difference in speed between the speed at which the let-off section 10 sends out the fabric M and the speed at which the conveying section 50 conveys the fabric M. The roller 63 of the dancer roller 6 is displaced upward from a reference position in accordance with the tension applied to the fabric M in section R1, and adjusts the magnitude of the tension applied to the fabric M transported through section R1.

[0028] The fabric M transported through section R2 is subjected to tension by the transport unit 50, the winding unit 20, the dancer roller 7, etc. In this embodiment, the magnitude of the tension applied to the fabric M transported through section R2 is determined by the difference in speed between the speed at which the transport unit 50 transports the fabric M and the speed at which the winding unit 20 winds up the fabric M. The roller 73 of the dancer roller 7 is displaced upward from the reference position in accordance with the tension applied to the fabric M transported through section R2, and adjusts the magnitude of the tension applied to the fabric M transported through section R1.

[0029] 2, the electrical configuration of the printer 100 will be described. The printer 100 has a CPU 31, a ROM 32, a RAM 33, a storage device , drive circuits 41 to 44, an input unit , and a display unit .

[0030] The CPU 31 controls the printer 100. The ROM 32 stores a table 91 (see FIG. 3) described later, the elastic modulus of the compression coil springs 62 and 72 (see FIG. 1), and various setting information. The RAM 33 temporarily stores various information. The storage device 34 is nonvolatile and stores a control program for executing the main processing (see FIG. 5) described later.

[0031] The CPU 31 inputs and outputs various signals to and from the ROM 32, RAM 33, storage device 34, drive circuits 41 to 44, encoders 14, 24, 54, displacement sensors 64, 74, input unit 35, and display unit 36. The input unit 35 accepts input of various information, instructions, etc. by the user and outputs them to the CPU 31. The display unit 36 ​​displays various screens based on instructions from the CPU 31.

[0032] The drive circuit 41 is connected to the let-off motor 13. The drive circuit 42 is connected to the take-up motor 23. The drive circuit 43 is connected to the transport motor 53. The drive circuit 44 is connected to the printing unit 4. The let-off motor 13, the take-up motor 23, and the transport motor 53 are, for example, stepping motors. The drive circuits 41, 42, 43, and 44 control the driving of the let-off motor 13, the take-up motor 23, the transport motor 53, and the printing unit 4 in response to instructions input from the CPU 31.

[0033] The encoders 14, 24, and 54 detect the rotational positions of the let-off motor 13, the take-up motor 23, and the conveying motor 53. The encoders 14, 24, and 54 are, for example, absolute value encoders. The encoders 14, 24, and 54 output signals indicating the detected rotational positions to the CPU 31. In this embodiment, the conveyance amount (m) of the fabric M is measured based on the rotational position detected by the encoder 54 and the diameter of the conveying roller 51.

[0034] The displacement sensors 64, 74 output signals indicating the displacement of the rollers 63, 73 from their reference positions to the CPU 31. The tension applied to the fabric M in section R1 is detected based on the displacement of the roller 63 detected by the displacement sensor 64 and the elastic modulus of the compression coil spring 62 stored in ROM 32. The tension applied to the fabric M in section R2 is detected based on the displacement of the roller 73 specified by the displacement sensor 74 and the elastic modulus of the compression coil spring 72 stored in ROM 32. In other words, the dancer rollers 6, 7 are configured to detect the tension applied to the fabric M in sections R1 and R2.

[0035] <Young's Modulus and Optimal Tension of Fabric M> Table 91 shown in FIG. 3 shows the relationship between the Young's modulus of fabric M and the optimal tension value when conveying fabric M. As shown in table 91, the optimal tension value of fabric M and the Young's modulus of fabric M have a one-to-one relationship according to Hooke's law. Therefore, the optimal tension value of fabric M can be determined by estimating the Young's modulus of fabric M. The Young's modulus of fabric M varies depending on the medium type of fabric M and the cross-sectional area of ​​fabric M. In this embodiment, the medium type of fabric M is a combination of the fiber type and the weave type. Examples of fiber types include cotton, polyester, and blended fibers of cotton and polyester. Examples of weave types include plain weave, twill weave, and satin weave. The cross-sectional area of ​​fabric M is the cross-sectional area of ​​fabric M when cut in a plane perpendicular to the forward direction F or the reverse direction B.

[0036] <Estimating Young's modulus of fabric M and determining optimal tension value through initial operation> In order to optimize the tension when transporting fabric M using table 91, it is necessary to estimate the Young's modulus of fabric M, which differs depending on the medium type and cross-sectional area of ​​fabric M. In printer 100, the Young's modulus of fabric M is estimated by executing initial operation. In initial operation, printer 100 transports fabric M in each of sections R1 and R2. In this embodiment, transport in section R1 and transport in section R2 in initial operation are similar, so the following description will focus on transport in section R1 in initial operation, and briefly describe transport in section R2.

[0037] In the initial operation, when the fabric M is conveyed in section R1, the conveying motor 53 is driven with the drive of the let-off motor 13 stopped, to convey the fabric M in the forward direction F. At this time, the conveyance amount (m) of the fabric M in section R1 and the tension (N) applied to the fabric M in section R1 are measured multiple times. Since the drive of the let-off motor 13 is stopped, the conveyance amount of the fabric M measured in section R1 is the elongation amount of the fabric M in section R1. In this embodiment, the elongation amount of the fabric M in section R1 is measured when the tension applied to the fabric M is 1 N, 2 N, 3 N, 4 N, and 5 N.

[0038] The relationship between the tension applied to the fabric M during the initial operation and the amount of stretch of the fabric M is as shown in Figure 4. Here, the Young's modulus E of the fabric M satisfies the relationship of the following equation 1 according to Hooke's law: E = f x L / (S x ΔL) ... (Equation 1) In equation 1, f is the magnitude (N) of the tension applied to the fabric M. L is the path length (m) of the section on the conveying path R. In conveying in section R1, L is the path length of section R1. S is the cross-sectional area (m2) of the fabric M. The cross-sectional area S of the fabric M is determined by the width and thickness of the fabric M. ΔL is the amount of stretch (m) in the section on the conveying path R. In conveying in section R1, ΔL is the amount of stretch in section R1.

[0039] Transforming Equation 1 yields Equation 2: f = (E × S / L) × ΔL (Equation 2) As shown in Equation 2, the magnitude of the tension f applied to the fabric M and the amount of stretch ΔL of the fabric M in section R1 are proportional to the proportionality constant (E × S / L). In other words, if the cross-sectional area S of the fabric M and the path length L1 of section R1 are known, the proportionality constant can be determined from the relationship between the tension applied to the fabric M in the initial operation and the amount of stretch of the fabric M, and the Young's modulus ER1 of the fabric M in section R1 can be estimated.

[0040] During conveyance in section R2 in the initial operation, the conveying motor 53 is driven with the take-up motor 23 stopped, to convey the fabric M in the opposite direction B. As with conveyance in section R1 in the initial operation, the conveyance amount (stretch amount) of the fabric M in section R2 and the tension applied to the fabric M in section R2 are measured. In the relationship in equation 1, L is the path length of section R2, and ΔL is the stretch amount in section R1. A proportionality constant is determined from the relationship between the tension applied to the fabric M in the initial operation and the stretch amount of the fabric M, and the Young's modulus ER2 of the fabric M in section R2 can be estimated from the known cross-sectional area S of the fabric M and the path length L2 of section R2.

[0041] In this embodiment, the arithmetic mean value of the Young's modulus ER1 of the fabric M in the section R1 and the Young's modulus ER2 of the fabric M in the section R2 is defined as the Young's modulus E of the fabric M (E = (ER1 + ER2) / 2). In the conveying device 1, the optimal value of the tension when conveying the fabric M is determined based on the estimated Young's modulus E of the fabric M and a table 91 (see FIG. 3).

[0042] <Main Processing> The main processing executed by the CPU 31 will be described with reference to Figure 5. In the main processing, the optimum value of tension applied to the fabric M is determined, and the fabric M is transported based on the determined optimum value. The program for the main processing is read from the ROM 32 when the printer 100 is powered on. This causes the CPU 31 to start the main processing. When the main processing starts, information on the medium type, width, and thickness of the fabric M is stored in the storage device 34.

[0043] When the main processing starts, the CPU 31 determines whether or not a change input signal has been received from the input unit 35 (S1). When changing the fabric M, the user inputs the change input signal using the input unit 35. The change of the fabric M is at least one of changing the medium type of the fabric M or changing the cross-sectional area of ​​the fabric M. The change input signal includes the change content of the fabric M.

[0044] When the CPU 31 determines that it has received a change input signal from the input unit 35 (S1: YES), it stores information on the medium type, width, and thickness of the fabric M after the change and information on the medium type, width, and thickness of the fabric M before the change in the memory device 34 based on the change contents of the fabric M contained in the change input signal (S2).

[0045] The CPU 31 determines whether the change in the fabric M includes a change in the medium type of the fabric M (S3). If the CPU 31 determines that the change in the fabric M includes a change in the medium type of the fabric M (S3: YES), it performs an initial operation in section R1 to determine the optimal value of the tension applied to the fabric M for the changed medium type (S4). In the initial operation in section R1, the CPU 31 drives the conveying motor 53 while stopping the drive of the delivery motor 13, and measures the amount of elongation of the fabric M in section R1 and the tension applied to the fabric M in section R1 multiple times. The amount of elongation of the fabric M in section R1 is measured based on the rotation position detected by the encoder 54. The tension applied to the fabric M in section R1 is measured based on the displacement of the roller 63 detected by the displacement sensor 64 of the dancer roller 6 and the elastic modulus of the compression coil spring 62.

[0046] The CPU 31 estimates the Young's modulus ER1 of the fabric M in section R1 based on the relationship between the elongation amount of the fabric M measured during the initial operation in section R1 and the tension applied to the fabric M (S5). The CPU 31 performs the initial operation in section R2 (S6). During the initial operation in section R2, the CPU 31 drives the feed motor 53 while stopping the winding motor 23, and measures the elongation amount of the fabric M in section R2 and the tension applied to the fabric M in section R2 multiple times. The CPU 31 estimates the Young's modulus ER2 of the fabric M in section R2 based on the relationship between the elongation amount of the fabric M measured during the initial operation in section R2 and the tension applied to the fabric M (S7).

[0047] The CPU 31 calculates the arithmetic mean value of the Young's modulus ER1 of the fabric M in the section R1 and the Young's modulus ER2 of the fabric M in the section R2 to estimate the Young's modulus E of the fabric M and stores this in the RAM 33 (S8). The CPU 31 determines the optimal value of the tension when conveying the fabric M based on the estimated Young's modulus E of the fabric M and the table 91 stored in the ROM 32 and stores this in the RAM 33 (S9). The CPU 31 returns the process to S1.

[0048] If the CPU 31 determines that the change in the fabric M does not include a change in the medium type of the fabric M (S2: NO), it determines that the change in the fabric M is the width or thickness of the fabric M and calculates the rate of change ε ​​of the cross-sectional area S of the fabric M (S11). The CPU 31 calculates the rate of change ε ​​of the cross-sectional area S of the fabric M based on the information on the width and thickness of the fabric M before and after the change stored in the storage device 34 in the processing of S2.

[0049] The CPU 31 updates the Young's modulus of the fabric M after the change (S12). The CPU 31 derives the Young's modulus E of the fabric M after the change by multiplying the Young's modulus E of the fabric M before the change, E0, by the rate of change ε ​​of the cross-sectional area S of the fabric M (E = E0 × ε), and stores this in the RAM 33, thereby updating the Young's modulus of the fabric M after the change. The CPU 31 determines the optimal value of the tension when conveying the fabric M based on the Young's modulus of the fabric M after the change and the table 91 stored in the ROM 32, and stores this in the RAM 33 (S13). The CPU 31 returns the process to S1.

[0050] When the CPU 31 determines that a change input signal has not been received from the input unit 35 (S1: NO), it determines (S21) whether a print instruction has been received from the input unit 35. When printing the fabric M, the user inputs a print instruction using the input unit 35. When the CPU 31 determines that a print instruction has not been received from the input unit 35 (S21: NO), it returns the process to S1.

[0051] When the CPU 31 determines that a print execution instruction has been received from the input unit 35 (S21: YES), it acquires the optimum tension value stored in the RAM 33 (S22). The CPU 31 drives the let-off motor 13, the take-up motor 23, and the transport motor 53 to start transporting the fabric M (S23). During transport of the fabric M, the CPU 31 controls the let-off motor 13, the take-up motor 23, and the transport motor 53 so that the tension of the fabric M becomes the optimum value acquired in S22.

[0052] The CPU 31 controls the driving of the printing unit 4 to print on the fabric M being transported along the transport path R (S24). The CPU 31 stops the driving of the printing unit 4 to stop printing on the fabric M, and stops the driving of the delivery motor 13, the take-up motor 23, and the transport motor 53 to stop transport of the fabric M (S25). The CPU 31 returns the process to S1.

[0053] <Operations and Effects of the Present Embodiment> As described above, the conveying device 1 of the printer 100 includes the sending unit 10, the winding unit 20, and the conveying unit 50. The CPU 31 of the printer 100 performs an initial operation (S4, S6). During the initial operation, the CPU 31 measures the elongation of the fabric M based on the rotational position detected by the encoder 54, and measures the tension applied to the fabric M based on the displacement of the roller 63 detected by the displacement sensor 64 and the elastic modulus of the compression coil spring 62. Based on the relationship between the elongation of the fabric M measured during the initial operation and the tension applied to the fabric M, the CPU 31 determines the optimal tension value for conveying the fabric M (S9). In this way, the printer 100 automatically determines the tension applied to the fabric M by performing the initial operation. Therefore, the printer 100 can reduce the effort required to adjust the tension applied to the fabric M compared to when the tension is adjusted manually by the user.

[0054] In the printer 100, the CPU 31 estimates the Young's modulus E based on the relationship between the amount of stretch of the fabric M measured during the initial operation and the tension applied to the fabric M (S8). Based on the estimated Young's modulus of the fabric M, the CPU 31 determines the optimal value of the tension when conveying the fabric M (S9). According to this, the optimal value of the tension of the fabric M and the Young's modulus of the fabric M have a one-to-one relationship according to Hooke's law, and the printer 100 can easily determine the optimal value of the tension of the fabric M by estimating the Young's modulus of the fabric M.

[0055] The conveying device 1 of the printer 100 has dancer rollers 6 and 7. The rollers 63 and 73 of the dancer rollers 6 and 7 are displaced in accordance with the tension applied to the fabric M being conveyed along the conveying path R. Therefore, the conveying device 1 can easily adjust the tension applied to the fabric M using the rollers 63 and 73.

[0056] When printing on the fabric M, the CPU 31 of the printer 100 controls the delivery motor 13, the take-up motor 23, and the transport motor 53 so that the tension of the fabric M is the optimum value determined based on the initial operation. This allows the printer 100 to transport the fabric M suitably without the fabric M stretching in the transport direction or causing wrinkles in the fabric M.

[0057] In the printer 100, the displacement sensors 64, 74 of the dancer rollers 6, 7 detect the displacement of the rollers 63, 73 from their reference positions. The dancer rollers 6, 7 detect the tension applied to the fabric M based on the displacement of the rollers 63, 73. In this way, the dancer rollers 6, 7 can detect the tension applied to the fabric M with a simple configuration.

[0058] In the printer 100, a proportionality constant is determined based on the relationship between the tension applied to the fabric M during the initial operation and the amount of stretch of the fabric M. The printer 100 estimates the Young's modulus of the fabric M in section R1 or section R2 from the relationship in equation 1, the determined proportionality constant, the cross-sectional area S of the fabric M, and the path length L of section R1 or section R2. This allows the printer 100 to easily estimate the Young's modulus using the relationship in equation 1.

[0059] The printer 100 has a ROM 32 that stores a table 91 that indicates the relationship between the Young's modulus E of the fabric M and the optimal value of the tension of the fabric M. As shown in Equation 1, the Young's modulus E of the fabric M is determined by a combination of the magnitude of the tension applied to the fabric M and the amount of stretch of the fabric M. The CPU 31 determines the optimal value of the tension applied to the fabric M based on the Young's modulus estimated by the initial operation and the table 91. This allows the printer 100 to perform the initial operation and easily determine the optimal value of the tension applied to the fabric M based on the magnitude of the tension applied to the fabric M and the amount of stretch of the fabric M measured during the initial operation.

[0060] In the printer 100, the dancer roller 6 is located between the delivery section 10 and the conveying section 50 on the conveying path R. This allows the printer 100 to easily adjust the tension of the fabric M conveyed through the section R1.

[0061] During the initial operation of conveying the fabric M in section R1, the CPU 31 of the printer 100 drives the conveying motor 53 while stopping the drive of the delivery motor 13, to convey the fabric M in the forward direction F. This allows the printer 100 to easily apply tension to the fabric M while conveying the fabric M in section R1 during the initial operation.

[0062] In the printer 100, the dancer roller 7 is located between the conveying section 50 and the winding section 20 on the conveying path R. This allows the printer 100 to easily adjust the tension of the fabric M conveyed through the section R2.

[0063] During the initial operation of conveying the fabric M in section R2, the CPU 31 of the printer 100 drives the conveying motor 53 while stopping the driving of the take-up motor 23, to convey the fabric M in the opposite direction B. This allows the printer 100 to easily apply tension to the fabric M while conveying the fabric M in section R2 during the initial operation.

[0064] In the printer 100, the dancer rollers 6, 7 have compression coil springs 62, 72 connected to rollers 63, 73. The dancer rollers 6, 7 detect the tension applied to the fabric M based on the displacement of the rollers 63, 73 and the elastic modulus of the compression coil springs 62, 72. In this way, the dancer rollers 6, 7 can detect the tension applied to the fabric M with a simple configuration.

[0065] In the printer 100, when the cross-sectional area S of the fabric M is changed, the CPU 31 derives the Young's modulus of the fabric M after the change by multiplying the Young's modulus of the fabric M before the change by the rate of change in the cross-sectional area S of the fabric M (S12). The CPU 31 changes the optimal value of the tension when conveying the fabric M based on the Young's modulus of the fabric M after the change and the table 91 stored in the ROM 32 (S13). According to this, when the medium type of the fabric M is not changed and the cross-sectional area S is changed, the printer 100 changes the optimal value of the tension of the fabric M without performing an initial operation. Therefore, the printer 100 can easily change the optimal value of the tension when the cross-sectional area S is changed.

[0066] <Modifications> The present invention can be modified in various ways from the above-described embodiment. The various modifications described below can be combined with each other as long as no contradiction occurs.

[0067] In the above embodiment, the printer 100 includes the conveying device 1 and the printing unit 4, but the printing unit 4 may be provided externally to the conveying device 1. In this case, the printing-related process in the main process (S24) and other processes may be distributed and processed by multiple CPUs 31. The conveying device 1 may not be provided with the printing unit 4, and only conveyance of the fabric M may be performed. In this case, the process of S24 may be omitted.

[0068] The printer 100 may use, for example, a microcomputer, an ASIC (Application Specific Integrated Circuits), an FPGA (Field Programmable Gate Array), etc. for control instead of the CPU 31. The main processing may be distributed processing using multiple CPUs 31, or may be processed by combining the CPU 31 with an ASIC, etc.

[0069] Non-transitory storage media such as the ROM 32 and the storage device 34 may be any storage media capable of retaining information regardless of the period for which the information is stored. Non-transitory storage media do not necessarily include temporary storage media (e.g., transmitted signals). The program for executing the main processing, the table 91, etc. may be downloaded (i.e., transmitted as a transmission signal) from a server connected to the network and stored in the storage device 34, etc. In this case, the program, etc. may be stored in a non-transitory storage medium such as an HDD provided in the server.

[0070] In the above embodiment, the dancer rollers 6, 7 detected the tension applied to the fabric M based on the displacement of the rollers 63, 73 detected by the displacement sensors 64, 74 and the elastic modulus of the compression coil springs 62, 72. However, the dancer rollers 6, 7 do not have to have the compression coil springs 62, 72. In this case, the rollers 63, 73 may be connected to a weight, for example, so that the rollers 63, 73 are displaced against the gravity of the weight due to the tension of the medium. In this case, the dancer rollers 6, 7 can also detect the tension applied to the fabric M based on the displacement of the rollers 63, 73 detected by the displacement sensors 64, 74.

[0071] The tension on the fabric M may be detected by a configuration other than the dancer rollers 6 and 7. For example, the conveying device 1 may have load cells in contact with the rollers 63 and 73 instead of the dancer rollers 6 and 7. In this case, the rollers 63 and 73 do not displace according to the tension on the fabric M, but the pressing force on the load cell changes. The load cell outputs an electrical signal according to the pressing force from the rollers 63 and 73, thereby detecting the tension on the fabric M. The conveying device 1 may also have blowers that blow air toward the fabric M from the rollers 63 and 73. In this case, the tension on the fabric M is detected in a non-contact manner based on the pressure between the rollers 63 and 73 and the fabric M. During initial operation, the conveying device 1 may estimate the tension on the fabric M from the torque and rotation amount applied to the let-off motor 13, the take-up motor 23, and the conveying motor 53.

[0072] In the above embodiment, the transport amount of the fabric M is measured based on the rotational position detected by the encoder 54 and the diameter of the transport roller 51. However, the transport amount of the fabric M may be measured based on the rotational position detected by the encoders 14 and 24 and the diameter of the rolls 11 and 21. The transport device 1 may have an encoder that detects the rotational positions of the rollers 81 to 84, and the transport amount of the fabric M may be measured based on the rotational position detected by this encoder and the diameter of the rollers 81 to 84.

[0073] In the above embodiment, the printer 100 estimated the Young's modulus and determined the optimal tension value of the fabric M based on the estimated Young's modulus. Here, since there is a one-to-one relationship between the Young's modulus and the optimal tension value, the printer 100 may determine the optimal tension value based on a combination of the tension f applied to the fabric M during the initial operation, the path length L of a section of the conveying path R, the cross-sectional area S of the fabric M, and the stretch ΔL during the initial operation in that section of the conveying path R. By defining the section of the conveying path R as a predetermined section, the path length L is uniquely determined. The predetermined section may be, for example, sections R1, R2, or the entire conveying path R. The ROM 32 stores a table 92 shown in FIG. 6 instead of table 91. Table 92 indicates the relationship between the optimal tension value and the combination of the tension f applied to the fabric M during the initial operation, the stretch ΔL during the initial operation, and the cross-sectional area S of the fabric M. In the initial operation, the printer 100 measures the tension f applied to the fabric M and the stretch amount ΔL of the fabric M, and can determine the optimum value of tension by referring to table 92. When determining the optimum value of tension by estimating Young's modulus as in the above embodiment, fewer components are required for the optimum value of tension, so the capacity of table 91 can be reduced compared to table 92. On the other hand, when determining the optimum value of tension without estimating Young's modulus, the processing can be simplified because Young's modulus is not estimated.

[0074] In the above embodiment, when printing on the fabric M, the CPU 31 of the printer 100 controls the let-off motor 13, the take-up motor 23, and the conveyance motor 53 so that the tension of the fabric M is the optimal tension value determined based on the initial operation. In contrast, the CPU 31 may control at least one of the let-off motor 13, the take-up motor 23, and the conveyance motor 53 so that the tension is the optimal value. For example, the CPU 31 may control the let-off motor 13 so that the tension is the optimal value. The CPU 31 may control the take-up motor 23 so that the tension is the optimal value. The CPU 31 may control the conveyance motor 53 so that the tension is the optimal value. The CPU 31 may control the let-off motor 13 and the take-up motor 23 so that the tension is the optimal value. The CPU 31 may control the let-off motor 13 and the conveyance motor 53 so that the tension is the optimal value. The CPU 31 may control the take-up motor 23 and the conveyance motor 53 so that the tension is the optimal value.

[0075] In the above embodiment, the printer 100 measures the tension applied to the fabric M and the amount of stretch of the fabric M multiple times during initial operation, and estimates the Young's modulus based on the proportionality constant determined by the relationship (see FIG. 4) between the tension applied to the fabric M and the amount of stretch of the fabric M. In contrast, the printer 100 may measure the tension applied to the fabric M and the amount of stretch of the fabric M once during initial operation, and estimate the Young's modulus of the fabric M using the relationship in Equation 1.

[0076] In the above embodiment, the printer 100 determines the optimal tension value based on the estimated Young's modulus and table 91. However, the printer 100 may determine the optimal tension value without using table 91. The Young's modulus E of the fabric M and the optimal tension value T satisfy the relationship of Equation 3 according to Hooke's law: T = E × S × ΔK / K (Equation 3) In Equation 3, K is the path length (m) of a predetermined section on the conveying path R. The predetermined section may be, for example, sections R1, R2, or the entire conveying path R. ΔK is the amount of stretch (m) of the fabric M conveyed through the predetermined section. By making the predetermined section and the initial operation section the same in Equation 3, the printer 100 can determine the optimal tension value without using table 91.

[0077] The transport device 1 may not have the dancer rollers 6. The transport device 1 may not have the dancer rollers 7.

[0078] In the above embodiment, the printer 100 performed both transport in section R1 and transport in section R2 during the initial operation. However, the printer 100 may perform either transport in section R1 or transport in section R2 during the initial operation. When the printer 100 performs both transport in section R1 and transport in section R2 during the initial operation, the Young's modulus E of the fabric M may be a value derived by another calculation method, such as the geometric mean value of the Young's modulus ER1 of the fabric M in section R1 and the Young's modulus ER2 of the fabric M in section R2.

[0079] The printer 100 performed the transport in section R1 in the initial operation by driving the feed motor 53 while stopping the drive of the let-off motor 13 and transporting the fabric M in the reverse direction F. In contrast, the printer 100 may perform the transport in section R1 in the initial operation by driving the let-off motor 13 while stopping the drive of the transport motor 53 and transporting the fabric M in the reverse direction B. The printer 100 may perform the transport in section R1 in the initial operation by driving the let-off motor 13 and the transport motor 53 and transporting the fabric M in the forward direction F or the reverse direction B. In this case, in order to apply tension to the fabric M, the speed at which the let-off unit 10 feeds out the fabric M by the let-off motor 13 and the speed at which the transport unit 50 transports the fabric M by the transport motor 53 may be different.

[0080] The printer 100 performed the transport in section R2 in the initial operation by driving the transport motor 53 with the take-up motor 23 stopped and transporting the fabric M in the reverse direction B. In contrast, the printer 100 may perform the transport in section R2 in the initial operation by driving the take-up motor 23 with the transport motor 53 stopped and transporting the fabric M in the forward direction F. The printer 100 may perform the transport in section R2 in the initial operation by driving the transport motor 53 and the take-up motor 23 and transporting the fabric M in the forward direction F or the reverse direction B. In this case, in order to apply tension to the fabric M, the speed at which the take-up motor 23 winds up the fabric M in the winding unit 20 and the speed at which the transport motor 53 transports the fabric M may be different.

[0081] In the above embodiment, when the medium type of the fabric M is not changed and the cross-sectional area S is changed, the optimal value of the tension of the fabric M is changed without performing the initial operation. In contrast, even when the medium type of the fabric M is not changed and the cross-sectional area S is changed, the printer 100 may perform the initial operation and change the optimal value of the tension of the fabric M based on the tension of the fabric M in the initial operation and the amount of stretch of the fabric M.

[0082] In the above embodiment, the platen 3 is plate-shaped, but is not limited to this. The platen 3 may be, for example, a belt conveyor having an endless belt that transports the fabric M. In this case, the driving of the belt conveyor may be controlled based on the determined optimal value of tension. A roller different from rollers 81 and 82 may be provided in section R1. Either roller 81 or 82 may not be provided in section R1. A roller different from rollers 83 and 84 may be provided in section R2. Either roller 83 or 84 may not be provided in section R2.

[0083] <Others> The dancer rollers 6 and 7 are an example of a "tension detection unit" of the present invention. The encoder 54 is an example of a "conveyance amount detection unit" of the present invention. The CPU 31 is an example of a "control unit" of the present invention. The processes of S4 and S6 are an example of an "initial operation process," "initial operation process," or "initial operation step" of the present invention. The process of S9 is an example of a "determination process," "determination process," or "determination step" of the present invention. The processes of S5, S7, and S8 are an example of an "estimation process" of the present invention. The rollers 63 and 73 are an example of a "displacement unit" of the present invention. Section R1 is an example of a "section between the delivery unit and the conveying unit on the conveying path." Section R2 is an example of a "section between the conveying unit and the winding unit on the conveying path." The ROM 32 is an example of a "memory" of the present invention. The compression coil springs 62 and 72 are an example of an "elastic body" of the present invention. The process of S13 is an example of a "change process" of the present invention.

[0084] REFERENCE SIGNS LIST 1 Conveying device 4 Printing unit 6, 7 Dancer roller 10 Feed-out unit 20 Winding unit 31 CPU 32 ROM 50 Conveying unit 54 Encoder 62, 72 Compression coil spring 63, 73 Roller 64, 74 Displacement sensor 91, 92 Table 100 Printer

Claims

1. A conveying device comprising: a feed section that feeds out a medium; a take-up section that takes up the medium fed out by the feed section; a conveying section that is provided on a conveying path between the feed section and the take-up section and conveys the medium; a tension detection section that detects the magnitude of tension applied to the medium conveyed between the feed section and the take-up section; a conveying amount detection section that detects the conveying amount of the medium conveyed between the feed section and the take-up section; and a control section, wherein the control section performs an initial operation process that conveys the medium by driving at least one of the feed section, the take-up section, and the conveying section; and a determination process that determines an optimal value of the tension based on the magnitude of the tension detected by the tension detection section and the conveying amount detected by the conveying amount detection section during the execution of the initial operation process.

2. The control unit, during execution of the initial operation process, further executes an estimation process to estimate the Young's modulus of the medium based on the magnitude of the tension detected by the tension detection unit and the transport amount detected by the transport amount detection unit, and in the determination process, determines the optimal value of the tension based on the Young's modulus estimated by the estimation process.

3. The conveying device according to claim 1, further comprising a displacement section that is displaceable in response to the tension applied to the medium conveyed between the delivery section and the winding section.

4. The conveying device described in claim 1, characterized in that the control unit controls at least one of the feeding of the medium by the feeding unit, the winding of the medium by the winding unit, and the conveying of the medium by the conveying unit so that the tension becomes the optimal value determined in the determination process.

5. The conveying device according to claim 3, wherein the tension detection unit detects the magnitude of the tension based on the displacement of the displacement unit.

6. The conveying device according to claim 2, wherein the control unit estimates the Young's modulus E of the medium in the estimation process based on the following formula 1: E = f × L / (S × ΔL) (Formula 1) where f is the magnitude of the tension detected by the tension detection unit during execution of the initial operation process, L is the length of one of the sections of the conveying path between the delivery unit and the conveying unit or the section of the conveying path between the conveying unit and the winding unit, S is the cross-sectional area of ​​the medium when cut in a plane perpendicular to the conveying direction of the medium, and ΔL is the amount of elongation of the medium in the one section, determined by the conveyance amount detected by the conveyance amount detection unit during execution of the initial operation process.

7. A conveying device according to claim 1, further comprising a memory that stores the relationship between the combination of the magnitude of the tension and the transport amount and the optimum value of the tension, and wherein the control unit, in the determination process, determines the optimum value of the tension based on the combination of the magnitude of the tension detected by the tension detection unit and the transport amount detected by the transport amount detection unit and the memory.

8. The conveying device according to claim 2, wherein the control unit, in the determination process, determines the optimal value T of the tension based on the Young's modulus E estimated by the estimation process and the following formula 2: T = E x S x ΔK / K ... (Formula 2) where S is the cross-sectional area of ​​the medium when cut in a plane perpendicular to the medium conveyance direction, K is the length of one of the sections in the conveyance path between the delivery section and the conveyance section, or the section in the conveyance path between the conveyance section and the winding section, and ΔK is the amount of elongation of the medium determined by the conveyance amount conveyed through the one section.

9. The conveying device according to claim 3, characterized in that the displacement section is located between the delivery section and the conveying section on the conveying path.

10. The conveying device described in claim 1, characterized in that, during the initial operation processing, the control unit stops one of the feeding of the medium by the feeding unit and the transport of the medium by the transport unit, while performing the other of the feeding of the medium by the feeding unit and the transport of the medium by the transport unit.

11. The conveying device according to claim 5, wherein the displacement section is located between the conveying section and the winding section of the medium in the conveying path.

12. The conveying device described in claim 1, characterized in that, during the initial operation processing, the control unit stops one of the winding of the medium by the winding unit and the transport of the medium by the transport unit, while performing the other of the winding of the medium by the winding unit and the transport of the medium by the transport unit.

13. The conveying device according to claim 3, characterized in that the tension detection unit has an elastic body connected to the displacement unit, and detects the magnitude of the tension based on the displacement of the displacement unit and the elastic modulus of the elastic body.

14. The conveying device of claim 2, wherein when the cross-sectional area of ​​the medium is changed after the optimal value of the tension has been determined by the determination process, the control unit further executes a change process to change the optimal value based on the Young's modulus estimated by the estimation process and the rate of change of the cross-sectional area.

15. A printer comprising: the transport device according to claim 1; and a printing unit that prints on the medium transported between the delivery unit and the take-up unit.

16. A control method for a conveying device comprising a feed section that feeds out a medium, a take-up section that takes up the medium fed out by the feed section, a conveying section that is provided on a conveying path between the feed section and the take-up section and conveys the medium, a tension detection section that detects the magnitude of tension applied to the medium conveyed between the feed section and the take-up section, and a conveyance amount detection section that detects the conveyance amount of the medium conveyed between the feed section and the take-up section, the control method comprising: an initial operation step of driving at least one of the feed section, the take-up section, and the conveying section to convey the medium; and a determination step of determining an optimal value for the tension based on the magnitude of the tension detected by the tension detection section and the conveyance amount detected by the conveyance amount detection section during the execution of the initial operation step.

17. A program to be executed by a computer that controls a transport device comprising: a feed section that feeds out a medium; a take-up section that takes up the medium fed by the feed section; a transport section that is provided on a transport path between the feed section and the take-up section and transports the medium; a tension detection section that detects the magnitude of tension applied to the medium transported between the feed section and the take-up section; and a transport amount detection section that detects the transport amount of the medium transported between the feed section and the take-up section, the program causing the computer to execute an initial operation step of transporting the medium by driving at least one of the feed section, the take-up section, and the transport section; and a determination step of determining an optimal value of the tension based on the magnitude of the tension detected by the tension detection section and the transport amount detected by the transport amount detection section during the execution of the initial operation step.

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