JP2020158292A - Media transfer device, recording device, and media transfer method - Google Patents

Abstract

To provide a media transfer device, a recording device, and a media transfer method with improved transfer accuracy by a transfer roller of media drawn from a roll body.SOLUTION: A recording device 10 includes: a transfer roller 21; an intermediate roller 41 that transfers media M drawn out from a roll body 36 to the transfer roller 21; and a control unit 50 that controls a drive of the transfer roller 21 and a drive of the intermediate roller 41. The control unit 50 performs a transfer operation for transferring the media M by driving the transfer roller 21 and the intermediate roller 41 after forming a slack in the media M between the transfer roller 21 and the intermediate roller 41 by driving the intermediate roller 41, and performs an intermediate slack elimination operation to eliminate the slack in the media M between the transfer roller 21 and the intermediate roller 41 by driving the intermediate roller 41 after the end of the transfer operation.SELECTED DRAWING: Figure 1

Description

The present invention relates to a media transport device for transporting media drawn from a roll body, a recording device provided with the media transport device, and a media transport method for transporting media drawn from a roll body.

Conventionally, a recording device that rotatably holds a roll body around which a medium such as paper is wound and discharges a liquid from a recording head to the medium drawn out from the roll body to record the medium. Is well known. Further, as a recording method of such a recording device, a serial recording method in which a recording operation of ejecting a liquid from a recording head to a medium and a conveying operation of conveying a medium to a recording area in which the recording head ejects a liquid are alternately repeated is well known. Is. In such a recording device, if the roll body is eccentric or tilted, a transfer error in which the transfer amount differs in the width direction of the medium occurs, and the transfer accuracy deteriorates. In Patent Document 1, the media is conveyed to the discharge region by using the conveying roller and the intermediate roller, and the eccentricity and inclination of the roll body are conveyed by loosening the media located between the conveying roller and the intermediate roller. A recording device that suppresses the influence on the transfer accuracy of the rollers is disclosed.

Japanese Unexamined Patent Publication No. 2017-170750

However, a decrease in transfer accuracy due to eccentricity or inclination of the roll body also occurs in the intermediate roller. Therefore, if the transfer operation is repeated with the media located between the transfer roller and the intermediate roller loosened, the transfer error in the intermediate roller is accumulated every time the transfer operation is performed, and as a result, the transfer accuracy of the transfer roller is improved. There was a risk that it would drop.

The media transport device that solves the above problems is a media transport device that transports the media drawn from the roll body, and the transport roller that transports the media and the media drawn from the roll body are transferred to the transport roller. An intermediate roller to be conveyed and a control unit for controlling the drive of the transfer roller and the drive of the intermediate roller are provided, and the control unit is provided between the transfer roller and the intermediate roller by the drive of the intermediate roller. After forming the slack of the media, the transport operation of transporting the media by driving the transport roller and the intermediate roller, and the period from the end of the transport operation to the start of the next transport operation are executed. The operation is an intermediate slack eliminating operation of eliminating the slack of the media between the transport roller and the intermediate roller by driving the intermediate roller.

The recording device that solves the above problems includes a media transfer device that conveys the media drawn from the roll body and a recording unit that records by ejecting a liquid to the media conveyed by the media transfer device. The media transport device includes a transport roller for transporting the media, an intermediate roller for transporting the media pulled out from the roll body to the transport roller, and driving of the transport roller and the intermediate. The control unit includes a control unit that controls the drive of the rollers, and the control unit forms a slack in the media between the transfer roller and the intermediate roller by driving the intermediate roller, and then the transfer roller and the intermediate. The transport operation of transporting the media by driving the rollers and the operation executed during the period from the end of the transport operation to the start of the next transport operation, the transport roller being driven by the intermediate roller. An intermediate slack relieving operation for relieving the slack of the media between the and the intermediate roller is executed.

The media transfer method for solving the above problems is a control method for a media transfer device that conveys the media drawn from the roll body in the transfer direction. The media transfer device includes a transfer roller that conveys the media and the roll. A control unit including an intermediate roller for transporting the media drawn from the body to the transport roller and controlling the drive of the transport roller and the drive of the intermediate roller is driven by the intermediate roller to drive the transport roller and the intermediate roller. After forming a slack in the media between the intermediate roller and the media, the media is conveyed by driving the transfer roller and the intermediate roller, and after the transfer process is completed, the intermediate roller is driven to drive the transfer roller. An intermediate slack relieving step of relieving the slack of the media between the and the intermediate roller is executed.

The figure which shows the schematic structure of the recording apparatus which carries out one Embodiment of a media transfer apparatus. The figure which shows typically the positional relationship of a roll body, an intermediate roller, a transport roller, and a recording head in a recording apparatus. A block diagram showing a part of the electrical configuration of a recording device. A functional block diagram showing the functional configuration of the feedback section. The figure which shows typically the tension acting on the media. A graph showing the relationship between the rotation speed and the intermediate roll load. A functional block diagram showing the functional configuration of the tension control unit. The figure which shows typically the rotational speed of a transfer motor, an intermediate motor, and a roll motor in a transfer operation and a preparatory operation. The figure which shows typically the state of the media located between the transport roller and the intermediate roller at the end of a transport operation. The figure which shows typically the state of the media located between the transport roller and the intermediate roller at the end of the intermediate slack elimination operation. The figure which shows typically the state of the media located between the intermediate roller and the roll holding part at the end of a roll loosening elimination operation. The figure which shows typically the state of the media located between the intermediate roller and the roll holding part at the end of a roll slack forming operation.

An embodiment of a media transfer device, a recording device, and a media transfer method will be described with reference to the drawings.
The recording device rotatably holds a roll body in which a medium is wound around a core member, and discharges a liquid from a recording head onto the surface of the media drawn from the roll body to record an image or the like on the media. To do. For example, a recording device is an inkjet large-format printer that prints on a medium such as paper by ejecting ink, which is an example of a liquid. A large format printer is a printer capable of printing on a medium M having an A3 short side width (297 mm) or more.

In FIG. 1, Y indicates a conveying direction in which the media is conveyed in the recording device, and X indicates a scanning direction which is orthogonal to the conveying direction Y and is a direction in which the recording head scans. The roll body is set so that the width direction of the media is along the scanning direction X.

As shown in FIGS. 1 and 2, the recording device 10 includes a recording unit 11 that records on the media M, and a transport unit 12 that transports the media M to the recording unit 11 in the transport direction Y. ing. The recording device 10 is a serial recording type recording device in which a recording operation by the recording unit 11 and a transfer operation by the transfer unit 12 are alternately performed.

The recording unit 11 includes a support base 13, a guide shaft 14, a carriage 15, a recording head 16, and a carriage drive mechanism 17.
The support base 13 extends in the scanning direction X. The support base 13 supports the media M transported to the discharge region set directly below the recording head 16 by the transport unit 12. The guide shaft 14 extends above the support base 13 in the scanning direction X. The guide shaft 14 supports the carriage 15 so as to be movable along the guide shaft 14. The carriage 15 is configured to be reciprocally movable along the guide shaft 14 by driving the carriage drive mechanism 17. A recording head 16 is mounted on the carriage 15. The recording head 16 is located on the support base 13 side with respect to the carriage 15. The recording head 16 records the media M by discharging the liquid to the media M supported by the support base 13. The recording unit 11 performs a recording operation by discharging a liquid from the recording head 16 while moving the carriage 15 along the guide shaft 14 by the carriage drive mechanism 17.

The transport unit 12 has a feed mechanism 20, a roll body drive mechanism 30, and an intermediate transport mechanism 40.
The feed mechanism 20 has a transfer roller 21 and a transfer roller drive unit 22.

The transport roller 21 is a nip roller composed of a transport drive roller 21a and a transport driven roller 21b that are rotatably supported with the scanning direction X as the rotation axis direction. The transport roller 21 is supported by being sandwiched between the transport drive roller 21a and the transport driven roller 21b from both the front and back sides of the media M. The transport roller 21 transports the media M in the transport direction Y by rotationally driving the transport drive roller 21a by the transport roller drive unit 22.

The transfer roller drive unit 22 includes a transfer motor 23, a transfer transmission mechanism 24, and a transfer rotation detection unit 25. The transfer motor 23 is, for example, a DC motor, and generates a transfer drive torque that rotationally drives the transfer roller 21.

The transport transmission mechanism 24 transmits the transport drive torque generated by the transport motor 23 to the transport roller 21 at a predetermined reduction ratio. In the transport roller 21, the transport drive roller 21a rotates when the transport drive torque is transmitted from the transport transmission mechanism 24, and the transport driven roller 21b rotates with the rotation of the transport drive roller 21a. The transport roller 21 is rotationally driven in the forward rotation direction in which the media M is conveyed toward the support base 13 by the forward rotation drive of the transfer motor 23, and the media M is driven in the reverse direction by the reverse rotation drive of the transfer motor 23. It is rotationally driven in the reverse direction of transportation toward 41.

The transfer rotation detection unit 25 detects the rotation position and rotation direction of the transfer output shaft 23a of the transfer motor 23. The transfer rotation detection unit 25 is composed of, for example, a rotary encoder composed of a disk-shaped scale provided on the transfer output shaft 23a of the transfer motor 23 and a photo interrupter.

The roll body driving mechanism 30 has a roll holding unit 31 and a roll driving unit 32.
The roll holding portion 31 rotatably holds the roll body 36 about an axis along the scanning direction X as a rotation axis. The roll holding portion 31 has a pair of holders 31a for holding the end portions of the roll body 36. Each of the pair of holders 31a has a rotating shaft portion (not shown) that is inserted into the core member of the roll body 36 from the outside in the scanning direction X.

The roll drive unit 32 includes a roll motor 33, a roll transmission mechanism 34, and a roll rotation detection unit 35.
The roll motor 33 is, for example, a DC motor, and generates a roll drive torque for rotationally driving the roll body 36.

The roll body drive mechanism 30 may be detachable from the recording device 10. Specifically, the roll motor 33 of the roll body drive mechanism 30 may be electrically connectable to the control unit 50 described later via a cable or the like.

The roll transmission mechanism 34 transmits the roll drive torque generated by the roll motor 33 to the roll holding unit 31 at a predetermined reduction ratio. In the roll holding portion 31, one holder 31a rotates when the roll drive torque is transmitted from the roll transmission mechanism 34, and the other holder 31a rotates with the rotation of the one holder 31a. As a result, the roll body 36 is rotationally driven with the scanning direction X as the rotation axis direction. The roll holding portion 31 is rotationally driven in the forward rotation direction in which the media M is pulled out from the roll body 36 by the forward rotation drive of the roll motor 33, and the media M is brought into the roll body 36 by the reverse rotation drive of the roll motor 33. It is rotationally driven in the reverse direction of winding.

The roll rotation detection unit 35 detects the rotation position and rotation direction of the roll output shaft 33a of the roll motor 33. The roll rotation detection unit 35 is composed of, for example, a rotary encoder composed of a disk-shaped scale provided on the roll output shaft 33a and a photo interrupter.

The intermediate transfer mechanism 40 has an intermediate roller 41 and an intermediate roller driving unit 42. The intermediate roller 41 is a nip roller composed of an intermediate drive roller 41a and an intermediate driven roller 41b rotatably supported with the scanning direction X as the rotation axis direction. The intermediate roller 41 is supported by being sandwiched between the intermediate drive roller 41a and the intermediate driven roller 41b from both the front and back surfaces of the media M. The intermediate roller 41 sandwiches the media M with a larger distance between the driving roller and the driven roller than the transport roller 21, for example, and a smaller holding force than the transport roller 21.

The intermediate roller drive unit 42 includes an intermediate motor 43, an intermediate transmission mechanism 44, and an intermediate rotation detection unit 45. The intermediate motor 43 is, for example, a DC motor, and generates an intermediate drive torque for driving the intermediate roller 41. The intermediate transmission mechanism 44 transmits the intermediate drive torque generated by the intermediate motor 43 to the intermediate roller 41 at a predetermined reduction ratio. In the intermediate roller 41, the intermediate drive roller 41a rotates by transmitting the intermediate drive torque from the intermediate transmission mechanism 44, and the intermediate driven roller 41b rotates with the rotation of the intermediate drive roller 41a. The intermediate roller 41 is rotationally driven in the forward rotation direction in which the media M is conveyed toward the transfer roller 21 by the forward rotation drive of the intermediate motor 43, and the media M is rolled by the reverse rotation drive of the intermediate motor 43. It is rotationally driven in the reverse direction of transporting toward 36.

The intermediate rotation detection unit 45 detects the rotation position and rotation direction of the intermediate output shaft 43a of the intermediate motor 43. The intermediate rotation detection unit 45 is composed of, for example, a rotary encoder composed of a disk-shaped scale provided on the intermediate output shaft 43a of the intermediate motor 43 and a photo interrupter.

The recording device 10 includes a control unit 50 that controls the recording device 10 in an integrated manner.
The control unit 50 includes a CPU (Central Processing Unit) 51, a ROM (Read Only Memory) 52, a RAM (Random Access Memory) 53, a PROM (Programmable ROM) 54, an ASIC (Application Technology), and an ASIC (Application) Technology). It includes a driver 56 and a bus 57. Further, each pulse signal is input to the control unit 50 from the transport rotation detection unit 25, the roll rotation detection unit 35, and the intermediate rotation detection unit 45.

The control unit 50 is communicably connected to, for example, a host device (not shown), and when it receives a recording job including recording data from the host device, it starts recording on the media M. The control unit 50 controls the recording unit 11 to move the carriage 15 in the scanning direction X while discharging the liquid from the recording head 16, and controls the transport unit 12 to record only the amount recorded by the recording unit 11. Recording is performed on the media M by alternately repeating the transport operation of feeding the media M in the transport direction Y. In the recording device 10, the media transfer device is composed of a transfer unit 12 and a control unit 50.

(Functional configuration of control unit 50)
The functional configuration of the control unit 50 will be described with reference to FIGS. 3 to 7.
The control unit 50 has various functional units embodied in collaboration with the hardware constituting the control unit 50 and the software stored in the ROM 52 or the like. The control unit 50 has a main control unit 61, a transfer motor control unit 62, a roll motor control unit 63, and an intermediate motor control unit 64 as various functional units related to the transfer of the media M.

The main control unit 61 issues various commands to the transfer motor control unit 62, the roll motor control unit 63, and the intermediate motor control unit 64. The main control unit 61 is configured to be able to issue a command so that each of the transfer motor 23, the roll motor 33, and the intermediate motor 43 is driven independently. Further, the main control unit 61 is configured to be able to issue a command so that the transfer motor 23, the roll motor 33, and the intermediate motor 43 are selectively and synchronously driven.

In the control unit 50, the main control unit 61, the transfer motor control unit 62, the roll motor control unit 63, and the intermediate motor control unit 64 control the motors 23, 33, 43, and various detection units 25, 35, 45. Based on the detected rotation position and rotation direction, various operations related to the transfer of the media M are performed.

Specifically, the control unit 50 performs a transfer operation of sending the media M to the region where the recording head 16 discharges the liquid, a period between the transfer operation and the transfer operation, that is, a preparatory operation during the execution of the recording operation. Further, the control unit 50 is intermediate when the intermediate motor 43 is driven at the same rotation speed and drive time as the load acquisition operation and the transfer operation that enable the acquisition of the intermediate roller load N for an arbitrary rotation speed V of the intermediate drive roller 41a. A reference current acquisition operation for acquiring the current flowing through the motor 43 is performed. When performing the transfer operation, the control unit 50 controls the tension T acting on the media M located between the transfer roller 21 and the intermediate roller 41 based on the information obtained through the load acquisition operation and the reference current acquisition operation.

The functional configurations of the transfer motor control unit 62, the roll motor control unit 63, and the intermediate motor control unit 64 will be described.
The transfer motor control unit 62 controls the drive of the transfer motor 23 via the driver 56. Specifically, the transfer motor control unit 62 controls the drive of the transfer motor 23 by controlling the supply of the constant pressure power supply to the transfer motor 23 by PWM (Pulse Width Modulation) control. For example, the transfer motor control unit 62 acquires the rotation position and rotation direction of the transfer output shaft 23a detected by the transfer rotation detection unit 25, and based on the acquired rotation position and rotation direction, the rotation position of the transfer drive roller 21a and the like. Get the rotation speed. The transfer motor control unit 62 generates a control signal by feedback control based on the rotation position and rotation speed of the transfer drive roller 21a, and outputs the generated control signal to the driver 56. The transfer motor control unit 62 has a feedback unit 652 that executes such feedback control.

The roll motor control unit 63 controls the drive of the roll motor 33 via the driver 56. Specifically, the roll motor control unit 63 controls the drive of the roll motor 33 by controlling the supply of the constant pressure power supply to the roll motor 33 by PWM control. The roll motor control unit 63 acquires the rotation position and rotation direction of the roll output shaft 33a detected by the roll rotation detection unit 35, and acquires the rotation position and rotation speed of the holder 31a based on the acquired rotation position and rotation direction. To do. The roll motor control unit 63 generates a control signal by feedback control based on the rotation position and rotation speed of the holder 31a, and outputs the generated control signal to the driver 56. The roll motor control unit 63 has a feedback unit 653 that executes such feedback control.

The intermediate motor control unit 64 controls the drive of the intermediate motor 43 via the driver 56. Specifically, the intermediate motor control unit 64 controls the drive of the intermediate motor 43 by controlling the supply of the constant pressure power supply to the intermediate motor 43 by PWM control. The intermediate motor control unit 64 acquires the rotation position and rotation direction of the intermediate output shaft 43a detected by the intermediate rotation detection unit 45, and based on the acquired rotation position and rotation direction, the rotation position and rotation speed of the intermediate drive roller 41a. To get. The intermediate motor control unit 64 generates a control signal by feedback control based on the rotation position and rotation speed of the intermediate drive roller 41a, and outputs the generated control signal to the driver 56. The intermediate motor control unit 64 has a feedback unit 654 that executes such feedback control.

Further, the intermediate motor control unit 64 generates a control signal by tension control for controlling the tension T acting on the media M located between the transfer roller 21 and the intermediate roller 41, and outputs the generated control signal to the driver 56. To do. The intermediate motor control unit 64 has a tension control unit 80 that executes such tension control.

(About the feedback section)
The feedback unit 652, 653, 654 will be described with reference to FIG. The feedback units 652, 653, 654 have the same basic configuration. Therefore, in the following, the configuration of the feedback unit will be described by taking the feedback unit 652 as an example, and the description of the feedback units 652 and 654 will be omitted. FIG. 4 is a block diagram functionally showing the feedback unit 652.

As shown in FIG. 4, the feedback unit 652 can execute position feedback control which is PID control regarding the rotation position of the transfer drive roller 21a and speed feedback control which is PID control regarding the rotation speed of the transfer drive roller 21a. It is configured. In the feedback unit 652, a target value for the rotation position or rotation speed of the transport drive roller 21a is input from the main control unit 61. The feedback unit 652 executes the position feedback control when the rotation position is input as the target value, and executes the speed feedback control when the rotation speed is input as the target value. The feedback unit 652 is not limited to the configuration for executing PID control, and may perform feedback control by PI control.

In the position feedback control, the feedback unit 652 has a position subtraction unit 66 in which a target position, which is a target value of the rotation position of the transport drive roller 21a, is input. The position subtraction unit 66 calculates a position deviation which is the difference between the target position and the rotation position calculated by the position calculation unit 67, and outputs the calculated position deviation to the target speed calculation unit 68. The position calculation unit 67 calculates the rotation position of the transfer drive roller 21a based on the pulse signal from the transfer rotation detection unit 25. The position subtraction unit 66 calculates a position deviation which is the difference between the target position input from the main control unit 61 and the rotation position calculated by the position calculation unit 67, and outputs the calculated position deviation to the target speed calculation unit 68. To do. The target speed calculation unit 68 calculates the target speed according to the position deviation calculated by the position subtraction unit 66 based on the table in which the position deviation and the target speed are associated, and the calculated target speed is calculated by the speed subtraction unit 69. Output to. The table is stored in advance in ROM 52 or the like.

The speed subtraction unit 69 calculates the speed deviation ΔV, which is the difference between the target speed and the rotation speed calculated by the rotation speed calculation unit 70. The rotation speed calculation unit 70 calculates the rotation speed of the transfer drive roller 21a based on the pulse signal from the transfer rotation detection unit 25 and the time measured by the timer 71.

The proportional term calculation unit 72 calculates the proportional term Qp by multiplying the velocity deviation ΔV by the proportional gain Kp as shown in the equation (1). The integral term calculation unit 73 calculates the integral term Qi by multiplying the integrated value of the velocity deviation ΔV by the integral gain Ki as shown in the equation (2). The differential term calculation unit 74 calculates the differential term Qd by multiplying the differential value of the velocity deviation ΔV by the differential gain Kd as shown in the equation (3).

Qp (j) = ΔV (j) × Kp ... (1)
Qi (j) = Q (j-1) + ΔV (j) × Ki ... (2)
Qd (j) = {ΔV (j) −ΔV (j-1)} × Kd… (3)
The addition unit 75 calculates the control instruction value Q of the transfer motor 23 by adding the proportional term Qp, the integration term Qi, and the differential term Qd, and outputs the calculated control instruction value Q to the PWM output unit 76.

The PWM output unit 76 outputs a PWM signal having a duty value corresponding to the input control instruction value Q to the driver 56 as a control signal. The PWM signal is, for example, a rectangular pulse signal having a predetermined period C. Based on the input PWM signal, the driver 56 controls the transfer motor 23 by PWM control so that the rotation speed of the transfer drive roller 21a becomes the target speed. The duty value is the ratio of the period during which the rectangular pulse is on to the predetermined period C. The larger the duty value, the larger the output value of the PWM signal, and the larger the value output to the driver 56.

In the speed feedback control, the target speed of the transport drive roller 21a calculated by the main control unit 61 is directly input to the speed subtraction unit 69. The feedback unit 652 executes speed feedback control, which is feedback control based on the speed deviation between the target speed and the rotation speed calculated by the rotation speed calculation unit 70, by directly inputting the target speed to the speed subtraction unit 69.

(About the tension working on media M)
In describing the tension control unit 80 that controls the tension acting on the media M located between the transfer roller 21 and the intermediate roller 41 with reference to FIGS. 5 to 7, between the transfer roller 21 and the intermediate roller 41. The various tensions that work on the media will be explained. First, with reference to FIG. 5, the tension T0 that works when the media M supported by the transfer roller 21 and the intermediate roller 41 is conveyed only by the transfer roller 21 will be described.

As shown in FIG. 5, in the above case, the media M is pulled by the transport drive roller 21a, so that the intermediate drive roller 41a is driven to rotate in the forward rotation direction. As a result, an intermediate roller load N, which is a load required to rotate the intermediate roller 41, is generated around the rotation axis of the intermediate roller 41. At this time, the tension T0 acting on the media M located between the intermediate drive roller 41a and the transport drive roller 21a is expressed by the following equation (4) by balancing the moments around the rotation axis of the intermediate drive roller 41a. The proportionality constant k1 is a constant set based on the results of experiments and simulations performed in advance, and R is the radius of the intermediate drive roller 41a.

T0 = k1 × N / R… (4)
Next, the tension T, which is the tension when the media M is fed by using the transport roller 21 and the intermediate roller 41, will be described. In this case, the intermediate drive roller 41a generates an output torque Tq that rotates the intermediate drive roller 41a in the forward rotation direction. As a result, a torque obtained by subtracting the output torque Tq from the intermediate roller load N acts around the rotation axis of the intermediate drive roller 41a. The tension T at this time can be expressed by the equation (5).

T = k1 × (N-Tq) / R ... (5)
According to the formula (5) and the above formula (4), the output torque Tq of the intermediate drive roller 41a can be expressed by the formula (6).

Tq = N- {(R / k1) x T} ... (6)
Here, it has been found from the results of experiments and simulations performed in advance that the intermediate roller load N has a linear relationship with the rotation speed V of the intermediate drive roller 41a. Therefore, when the roll body 36 is mounted, the control unit 50 executes a load acquisition operation that makes it possible to calculate the intermediate roller load N with respect to an arbitrary rotation speed V of the intermediate drive roller 41a. The load acquisition operation will be described later.

From the above, among the parameters included in the equation (6), the proportionality constant k1, the radius R of the intermediate drive roller 41a, and the intermediate roller load N are known values. Therefore, by inputting the target tension Ta into the equation (6), the output torque Tq of the intermediate drive roller 41a required to generate the target tension Ta in the media M conveyed by the transfer roller 21 and the intermediate roller 41 can be obtained. It becomes possible to calculate. Then, when the output torque Tq is calculated, the intermediate drive torque of the intermediate motor 43 can be calculated.

The target tension Ta is set to a value that prevents the media M transported by the transport roller 21 and the intermediate roller 41 from skewing and maintains a good state without breaking. The target tension Ta is set according to the characteristics of the media M based on the results of experiments and simulations performed in advance. The set target tension Ta is stored in the ROM 52 of the control unit 50 or the like in association with the characteristics of the media M. Information about the characteristics of the media M is input to the control unit 50 through an operation by the user through an operation unit (not shown) or through an operation by the user of a host device (not shown). The main control unit 61 selects a target tension Ta based on the input information regarding the characteristics of the media M, and outputs the selected target tension Ta to the tension control unit 80.

(About intermediate roller load N)
The above-mentioned intermediate roller load N will be described in more detail with reference to FIG. As described above, it is known that the intermediate roller load N has a linear relationship with the rotation speed V of the intermediate drive roller 41a. The control unit 50 executes a load acquisition operation that enables acquisition of the intermediate roller load N with respect to an arbitrary rotation speed V of the intermediate drive roller 41a.

As shown in FIG. 6, in the load acquisition operation, the first intermediate roller load N1 corresponding to the first rotation speed V1 and the second intermediate roller load corresponding to the second rotation speed V2 larger than the first rotation speed V1. N2 and are acquired. As a result, the relational expression N = a × V + b of the linear function shown based on the first rotation speed V1, the first intermediate roller load N1, the second rotation speed V2, and the second intermediate roller load N2 can be derived. Therefore, the intermediate roller load N at an arbitrary rotation speed V of the intermediate drive roller 41a is linear interpolation using the first rotation speed V1, the first intermediate roller load N1, the second rotation speed V2, and the second intermediate roller load N2. It becomes possible to calculate by.

In the load acquisition operation, the main control unit 61 inputs the first rotation speed V1 as the target speed to the intermediate motor control unit 64. The intermediate motor control unit 64 drives the intermediate motor 43 so that the intermediate drive roller 41a rotates at the first rotation speed V1 in the forward rotation direction by speed feedback control with the first rotation speed V1 as the target speed. When the rotation speed V of the intermediate drive roller 41a stabilizes at the first rotation speed V1, the main control unit 61 acquires the duty value based on the PWM signal at that time as the first intermediate roller load N1. The main control unit 61 stores the acquired first intermediate roller load N1 in the RAM 53 or PROM 54 in association with the first rotation speed V1.

When the first intermediate roller load N1 is acquired, the main control unit 61 inputs the second rotation speed V2 as the target speed to the intermediate motor control unit 64. The intermediate motor control unit 64 drives the intermediate motor 43 so that the intermediate drive roller 41a rotates at the second rotation speed V2 in the forward rotation direction by speed feedback control with the second rotation speed V2 as the target speed. When the rotation speed V of the intermediate drive roller 41a stabilizes at the second rotation speed V2, the main control unit 61 acquires the duty value based on the PWM signal at that time as the second intermediate roller load N2. The main control unit 61 stores the acquired second intermediate roller load N2 in the RAM 53 or PROM 54 in association with the second rotation speed V2.

The main control unit 61 makes it possible to acquire the intermediate roller load N with respect to an arbitrary rotation speed V of the intermediate drive roller 41a through such a load acquisition operation. The main control unit 61 can also acquire the intermediate drive roller 41a based on the value of the integration term at the time when the rotation speed V becomes stable at the first rotation speed V1. Further, the main control unit 61 can also acquire the intermediate drive roller 41a based on the value of the integration term at the time when the rotation speed V becomes stable at the second rotation speed V2.

By the way, the intermediate roller load N may fluctuate even if the intermediate drive roller 41a is driven at a constant rotation speed V. For example, the intermediate roller load N varies depending on the inclination of the media M with respect to the transport direction Y, the fluctuation of the frictional force between the media M and the intermediate roller 41, the fluctuation of the Young's modulus of the media M, and the like. When the intermediate roller load N fluctuates, the tension fluctuates if the output torque Tq of the intermediate drive roller 41a is kept constant. In this case, the tension fluctuates with each transfer operation, and the transfer amount fluctuates with each transfer operation, resulting in defects such as banding in the image recorded on the media M. In view of these circumstances, the tension control unit 80 calculates the correction target tension Tb corrected for the target tension Ta, and calculates the control instruction value of the intermediate motor 43 using the calculated correction target tension Tb. In other words, the tension control unit 80 corrects the target tension Ta so that the transport amount for each transport operation is constant.

(About tension control unit 80)
FIG. 7 is a block diagram showing a functional configuration of the tension control unit 80.
As shown in FIG. 7, the tension control unit 80 includes a drive current calculation unit 81, a reference current calculation unit 82, a low-pass filter 83, 84, a current subtraction unit 85, a conversion unit 86, and a deviation calculation unit 87. A correction amount calculation unit 88, a correction unit 89, and a PWM output unit 76 are provided.

The drive current calculation unit 81 calculates the drive current Ia (k), which is the current flowing through the intermediate motor 43 during the transfer operation, in a predetermined calculation cycle, for example, a 1 msec cycle. Ia (k) indicates the drive current I calculated at the kth time in a predetermined calculation cycle. The drive current calculation unit 81 inputs the calculated drive current Ia (k) to the current subtraction unit 85 via the low-pass filter 83.

The reference current calculation unit 82 calculates the reference current Ib (k), which is the current flowing through the intermediate motor 43 during the reference current acquisition operation, in the same calculation cycle as the drive current calculation unit 81. In the reference current acquisition operation, the drive current of the intermediate motor 43 is acquired when the intermediate drive roller 41a is driven at the same rotation speed and the same drive time as during the transfer operation with the media M loosened on both sides of the intermediate roller 41. It is an operation.

In the reference current acquisition operation, the main control unit 61 loosens the media M on both sides of the intermediate roller 41 through the transfer motor control unit 62 and the roll motor control unit 63, and then rotates the same as during the transfer operation through the intermediate motor control unit 64. The intermediate drive roller 41a is driven at a speed and the same drive time. The main control unit 61 executes the reference current acquisition operation, for example, before the start of each recording job. The main control unit 61 may perform the reference current acquisition operation a plurality of times for each recording job, and the reference current calculation unit 82 may acquire the average value as the reference current Ib (k). The main control unit 61 stores the reference current Ib (k) calculated by the reference current calculation unit 82 in the RAM 53, and ends the reference current acquisition operation. The reference current calculation unit 82 inputs the reference current Ib (k) calculated in this way to the current subtraction unit 85 via the low-pass filter 84.

Here, the current I flowing through the intermediate motor 43 is calculated by the following equation (7).
I = (E × D-Ke × ω) / Rr… (7)
In the formula (7), E is the voltage of the power supply, and D is the duty value output to the intermediate motor 43. Ke is the counter electromotive force constant of the intermediate motor 43, ω is the rotation speed of the intermediate motor 43, and Rr is the resistance of the intermediate motor 43. The counter electromotive force constant Ke and the resistance Rr of the intermediate motor 43 vary depending on the temperature. Therefore, the counter electromotive force constant Ke and the resistor Rr may be corrected based on the detection signal from the temperature detection unit that detects the temperature of the intermediate motor 43.

The current subtraction unit 85 calculates the tension current Ic (k) by subtracting the reference current Ib (k) from the drive current Ia (k). Then, the current subtraction unit 85 calculates the average tension current Iave, which is the average value of the calculated plurality of tension currents Ic (k), and the maximum tension current Imax, which is the maximum value of the plurality of tension currents Ic (k). .. The current subtraction unit 85 inputs the calculated average tension current Iave and the maximum tension current Imax to the conversion unit 86.

The conversion unit 86 calculates the average tension Tave based on the average tension current Iave and the maximum tension Tmax based on the maximum tension current Imax. The conversion unit 86 calculates the detection tension Tc obtained by weighting the calculated average tension Tave and the maximum tension Tmax, and outputs the calculated detection tension Tc to the deviation calculation unit 87.

The conversion unit 86 calculates the average tension Tave and the maximum tension Tmax by the following equations (8) and (9), respectively. In equations (8) and (9), Kt is the torque constant of the intermediate motor 43, Z is the reduction ratio of the intermediate transmission mechanism 44, and R is the radius of the intermediate drive roller 41a.

Tave = Iave x Kt x Z / R ... (8)
Tmax = Imax x Kt x Z / R ... (9)
The conversion unit 86 calculates the detection tension Tc by the formula (10) shown below.

Tc = {Ka × Tave / (Ka + Km)}
+ {Km × Tmax / (Ka + Km)}… (10)
Ka and Km are arbitrary weight coefficients indicating the weights of the average tension Tave and the maximum tension Tmax in the calculation of the detection tension Tc.

The values of Ka and Km are set from the viewpoint of how the detected tension Tc correlating with the transport amount can be calculated from the tension current Ic (k) that fluctuates in a complicated manner during one transport operation. Since the waveform of the tension current Ic (k) changes depending on, for example, the feed rate of the media M and the transport amount of the media M in one transport operation, a plurality of patterns of Ka and Km values corresponding to these are prepared. Is preferable. The pattern of Ka and Km values includes a pattern in which one of them is 0. That is, the detected tension Tc may be equal to the average tension Tave, and the detected tension Tc may be equal to the maximum tension Tmax. For example, when the transport amount of the media M in one transport operation is relatively small, the maximum tension Tmax has a large influence on the transport amount, so that the detection tension Tc may be calculated only by the maximum tension Tmax.

Further, for example, when the feed rate of the media M is high, the difference between the average tension Tave and the maximum tension Tmax may fluctuate depending on the specific gravity of the media M and the like. Therefore, both the average tension Tave and the maximum tension Tmax are used for detection. The tension Tc may be calculated. When calculating the detected tension Tc using both the average tension Tave and the maximum tension Tmax, the values of Ka and Km are adjusted according to the fluctuation amount of the difference between the average tension Tave and the maximum tension Tmax to adjust the average tension Tave and the maximum tension Tc. The weighting of the tension Tmax may be changed. If the difference between the average tension Tave and the maximum tension Tmax is stable without much fluctuation, the detection tension Tc may be obtained only from the average tension Tave.

The deviation calculation unit 87 calculates the tension deviation ΔT (n), which is the deviation of the detection tension Tc (n-1) output by the conversion unit 86 with respect to the target tension Ta (n) input from the main control unit 61. The calculated tension deviation ΔT (n) is output to the correction amount calculation unit 88.

The value in parentheses means the number of transfer operations. For example, the detection tension Tc (n-1) indicates the (n-1) th time, that is, the detection tension Tc based on the previous transfer operation. Ta (n) means the nth time, that is, the target tension Ta at the time of the current transfer operation. The same applies hereinafter.

The correction amount calculation unit 88 calculates the deviation integrated value ΔTg (n) obtained by integrating the tension deviation ΔT (n) output by the deviation calculation unit 87 by the following equation (11), and the calculated deviation integrated value ΔTg. The tension correction amount Th (n) is calculated by the equation (12) based on (n).

ΔTg (n) = ΔTg (n-1) + ΔT (n)… (11)
Th (n) = ΔTg (n) × G ... (12)
In the equation (12), G is a gain. Further, the deviation integral value ΔTg is reset when any one of the attachment of the roll body 36, the change of the target tension Ta, and the change of the feed rate of the media M is made.

The correction unit 89 adds a value obtained by adding the target tension Ta (n) input from the main control unit 61 and the tension correction amount Th (n) output from the correction amount calculation unit 88 to the correction target tension Tb (n). Is output to the PWM output unit 76.

The PWM output unit 76 calculates the output torque Tq of the intermediate drive roller 41a by substituting the correction target tension Tb (n) output from the correction unit 89 into the above equation (6). The PWM output unit 76 outputs a PWM signal having a duty value proportional to the output torque Tq to the driver 56. The driver 56 drives the intermediate drive torque of the intermediate motor 43 by PWM control based on the PWM signal output from the PWM output unit 76. As a result, the intermediate motor control unit 64 can perform control for realizing the correction target tension Tb (n).

(Transporting method of media M)
An example of a method of transporting the media M by the control unit 50 will be described with reference to FIGS. 8 to 12. In FIG. 8, the horizontal axis represents the time, and the vertical axis represents the rotation speeds of the transport roller 21, the intermediate roller 41, and the roll holding portion 31. The + rotation speed indicates the rotation speed during the forward rotation drive, and the-rotation speed indicates the rotation speed during the reverse rotation drive.

As shown in FIG. 8, when the transfer operation is started at time t1, the control unit 50 first sends the media M toward the transfer roller 21 while performing tension control by the intermediate motor control unit 64. The intermediate roller 41 is driven to rotate in the forward direction. Specifically, the intermediate roller 41 is driven in the forward rotation while the drive of the transport roller 21 is stopped. In other words, the drive start timing t1 of the transport roller 21 is set earlier than the drive start timing t2 of the intermediate roller 41.

That is, as shown in FIG. 9, the control unit 50 forms a small slack 95 between the transport roller 21 and the intermediate roller 41, and then media M located between the transport roller 21 and the intermediate roller 41. The intermediate motor 43 is driven in the forward rotation so that the state in which the predetermined tension T is applied is maintained.

At the next time t2, the control unit 50 performs a predetermined transfer amount toward the discharge region of the recording head 16 while performing position feedback control by the transfer motor control unit 62 while maintaining the tension control by the intermediate motor control unit 64. The conveyor motor 23 is driven in the forward rotation so as to feed the media M only. At this time, since the above-mentioned slack 95 is formed between the transport roller 21 and the intermediate roller 41, the transport of the media M by the transport roller 21 can be smoothly started. Further, the intermediate roller 41, which has been driven to rotate in the normal direction in advance, can rotate in the normal direction without delaying the acceleration of the transport roller 21 due to its own inertia or the like. When the transport operation is completed at the time t3 when the media M is transported by a predetermined transport amount, the recording operation is executed by the recording unit 11 until the time t8 when the next transport operation is started.

As shown in FIG. 8, the control unit 50 executes the preparatory operation during the execution of the recording operation. The preparatory operation is an operation for improving the transfer accuracy of the transfer roller 21 in the next transfer operation.
Immediately after the time t3 when the transfer operation ends, the control unit 50 executes an intermediate slack elimination operation for eliminating the slack of the media M located between the transfer roller 21 and the intermediate roller 41.

In the intermediate slack elimination operation, the control unit 50 reversely drives the intermediate roller 41 through the intermediate motor control unit 64 by speed feedback control with the intermediate slack elimination speed as the target speed. The intermediate slack elimination speed is set according to the characteristics of the media M based on the results of experiments and simulations performed in advance. The control unit 50 selects the target speed based on the intermediate slack elimination speed table in which the elapsed time from the start of the intermediate slack elimination operation and the intermediate slack elimination speed at each elapsed time are defined. In the intermediate slack elimination speed table, the intermediate slack elimination speed that increases monotonically up to a predetermined time is specified, and after that time, the upper limit of the intermediate slack elimination speed is specified. The intermediate slack elimination speed table is a table in which the intermediate slack elimination speed is associated with each characteristic of the media M, and is stored in the ROM 52 in advance.

In addition to the speed feedback control, torque feedback control with the intermediate slack elimination torque as the target torque may be performed at the same time. The intermediate slack eliminating torque is set according to the characteristics of the media M based on the results of experiments and simulations performed in advance, similarly to the intermediate slack eliminating speed. As a result, it is possible to further suppress that the impact force when the slack 95 of the media M between the transport roller 21 and the intermediate roller 41 is eliminated becomes excessively large.

In the intermediate slack eliminating operation, the control unit 50 substitutes the duty value output by the PWM output unit 76 and the rotation speed based on the rotation position detected by the intermediate rotation detection unit 45 into the above equation (7), thereby causing the intermediate motor 43. Calculate the intermediate slack elimination current that has flowed to. At this time, the intermediate slack eliminating current is a drive current value indicating the drive torque, and the control unit 50 functions as a drive torque acquisition unit. Then, the control unit 50 intermediates when the intermediate slack elimination current reaches a predetermined intermediate slack elimination value, that is, when the tension T acting on the media M located between the transport roller 21 and the intermediate roller 41 reaches a predetermined value. The slack elimination operation is terminated. The intermediate slack elimination value is a value defined for each characteristic of the media M based on the results of predetermined experiments and simulations. The intermediate slack elimination value is a value at which the media M does not slip in the transport roller 21. The intermediate slack elimination value is associated with the characteristics of the media M and is stored in the ROM 52 in advance. The method by which the control unit 50 acquires the drive torque of the intermediate motor 43 is not limited to the method of measuring the intermediate slack eliminating current flowing through the intermediate motor 43. For example, a method of acquiring the duty value D output by the PWM output unit 76 in the equation (7) as it is may be used.

As shown in FIG. 10, when the intermediate slack eliminating operation is completed at time t4, the media M located between the transport roller 21 and the intermediate roller 41 is in a state in which an appropriate tension is applied. As described above, the intermediate slack eliminating operation is an operation of eliminating the transport error caused by the transport operation of the media M located between the transport roller 21 and the intermediate roller 41. The transport error is a difference in the transport amount at both ends of the media M in the width direction. In the process of eliminating the intermediate slack, the transport error is eliminated by causing a partial slip between the media M and the intermediate roller 41 at one end where the tension is increased at both ends in the width direction of the media M. .. As a result, in the next transfer operation, the difference in tension at both ends in the width direction of the media M and the difference in the amount of transfer at both ends in the width direction due to the difference in tension are eliminated. As a result, it is possible to reduce the influence of the transfer error caused by the current transfer operation on the next transfer operation.

As shown in FIG. 8, in the preparatory operation, the control unit 50 eliminates the slack of the media M located between the intermediate roller 41 and the roll holding unit 31 immediately after the time t3 when the transfer operation is completed. Perform the resolution operation.

In the roll slack elimination operation, the control unit 50 reversely drives the roll holding unit 31 through the roll motor control unit 63 by speed feedback control with the roll slack elimination speed as the target speed. The control unit 50 selects a target speed based on a roll slack eliminating speed table in which the elapsed time from the start of the roll slack eliminating operation and the roll slack eliminating speed at each elapsed time are defined. In the roll slack elimination speed table, the roll slack elimination speed that increases monotonically up to a predetermined time is specified, and after that time, the upper limit of the roll slack elimination speed is specified.

In addition to the speed feedback control, torque feedback control with the roll slack eliminating torque as the target torque may be performed at the same time. The roll slack eliminating torque is set according to the characteristics of the media M based on the results of experiments and simulations performed in advance, similar to the roll slack eliminating speed. As a result, it is possible to further suppress that the impact force when the slack of the media M between the intermediate roller 41 and the roll holding portion 31 is eliminated becomes excessively large.

The roll slack elimination speed table is a table in which the roll slack elimination speed is associated with each characteristic of the media M, and is stored in the ROM 52 in advance. Further, the rate of increase of the roll slack elimination speed is often smaller than the intermediate slack elimination speed, and the upper limit of the roll slack elimination speed is preferably larger than the upper limit of the intermediate slack elimination speed. According to such a configuration, when the roll slack eliminating operation and the intermediate slack eliminating operation are performed at the same time, the intermediate slack eliminating current is suppressed from being affected by the roll slack eliminating operation.

In the roll slack eliminating operation, the control unit 50 substitutes the duty value output by the PWM output unit 76 and the rotation speed based on the rotation position detected by the roll rotation detection unit 35 into the above equation (7), thereby causing the roll motor 33. Calculate the roll slack elimination current that has flowed to. Then, when the roll slack elimination current reaches a predetermined roll slack elimination value, the main control unit 61 reaches a predetermined value of the tension T acting on the media M located between the intermediate roller 41 and the roll holding unit 31. Then, the roll slack eliminating operation is completed. The roll slack elimination value is a value defined for each characteristic of the media M based on the results of predetermined experiments and simulations. The roll slack elimination value is a value at which the media M does not slip in the intermediate roller 41. The roll slack elimination value is associated with the characteristics of the media M and is stored in the ROM 52 in advance.

As shown in FIG. 11, when the roll slack eliminating operation is completed at time t5, the media M located between the intermediate roller 41 and the roll holding portion 31 is in a state in which an appropriate tension is applied. The moderate tension is a tension such that the quality of the image formed on the media M reaches a desired quality. The roll slack eliminating operation eliminates the transport error occurring in the media M located between the intermediate roller 41 and the roll holding portion 31. The roll slack eliminating operation eliminates or alleviates the influence of the eccentricity and inclination of the roll body 36, that is, a state in which the amount of slack is large at one of both ends in the width direction of the media M. In the process of removing the roll slack, when the tension on one of both ends of the width of the media M becomes larger than that on the other, the roll body 36 partially and slightly slides with respect to the roll holding portion 31, and thereafter. The difference in the amount of slack at both ends of the width of the media M after the roll slack forming operation is eliminated or alleviated. In this way, the accumulation of differences in the amount of slack at both ends of the width of the media M is eliminated.

As shown in FIG. 8, in the preparatory operation, the control unit 50 executes the roll slack forming operation at time t6 after the intermediate slack eliminating operation and the roll slack eliminating operation are completed.
In the roll slack forming operation, the control unit 50 drives the roll motor 33 in the forward rotation by position feedback control with the slack forming position as the target position through the roll motor control unit 63. The slack forming position is a rotation position where the media M is pulled out from the roll body 36 by a predetermined amount of slack. This slack amount is set to a value larger than the transport amount of the media M in the transport operation. The amount of slack is set to a value that is about 8 mm larger than the amount of transportation, for example. The control unit 50 ends the roll slack forming operation when the rotation position based on the pulse signal from the roll rotation detecting unit 35 reaches the slack forming position.

As shown in FIG. 12, when the roll slack forming operation is completed at time t7, an initial slack 96 having a slack amount larger than the amount conveyed by the transfer operation is formed between the intermediate roller 41 and the roll holding portion 31. .. As a result, the media M located between the intermediate roller 41 and the roll holding portion 31 is configured so that tension is not applied during the transport operation. In the roll slack forming operation, the initial slack 96 is formed on the media M located between the intermediate roller 41 and the roll holding portion 31, so that the roll body 36 is eccentric with respect to the transfer accuracy of the intermediate roller 41 during the transfer operation. And tilt to prevent direct action. The roll slack relieving operation described above is also an operation of relieving the initial slack 96 formed in such a preparatory movement. Then, the control unit 50 starts the transport operation again at the time t8 when the recording operation ends.

The effect of the above embodiment will be described.
(1) In the transport operation, the control unit 50 starts transporting the media M only by the intermediate roller 41 prior to the transport of the media M by the transport roller 21 and the intermediate roller 41. Further, the control unit 50 performs an intermediate slack elimination operation for eliminating the slack caused by the preceding drive of the intermediate roller 41 between the current transfer operation and the next transfer operation.

By starting the transfer of the media M by the intermediate roller 41 in advance, a small slack 95 is formed between the transfer roller 21 and the intermediate roller 41. As a result, the transfer of the media M by the transfer roller 21 can be started smoothly. Further, since the intermediate roller 41 is driven in the forward rotation in advance, the intermediate roller 41 can be driven in the forward rotation without delaying the acceleration of the transport roller 21 due to the inertia of the intermediate roller 41 or the like. Further, since the transport of the media M by the transport roller 21 is less affected by the eccentricity and inclination of the roll body 36, the transport accuracy by the transport roller 21 can be improved.

Further, by the intermediate slack eliminating operation, it is possible to eliminate the transport error caused by the transport error of the media M located between the transport roller 21 and the intermediate roller 41 due to the transport of the media M to the transport roller 21 by the intermediate roller 41. it can. As a result, with respect to the media M located between the transport roller 21 and the intermediate roller 41, the influence of the transport error caused by the current transport operation on the next transport operation can be reduced.

That is, the transfer by the transfer roller 21 is not easily affected by the eccentricity and inclination of the roll body 36, and the intermediate roller 41 generated in the previous transfer operation on the media M located between the transfer roller 21 and the intermediate roller 41. The influence of the transfer error on the next transfer operation is reduced. As a result, the transfer by the transfer roller 21 can be performed with high accuracy.

(2) In the intermediate slack elimination operation, the control unit 50 acquires the intermediate slack elimination current, which is the current flowing through the intermediate motor 43, as the drive torque, and when the acquired intermediate slack elimination current reaches the intermediate slack elimination value, it is intermediate. The slack elimination operation is terminated. According to such a configuration, the tension T acting on the media M located between the intermediate roller 41 and the transport roller 21 can be grasped more accurately. As a result, in the intermediate slack eliminating operation, it is possible to prevent the media M located between the intermediate roller 41 and the transport roller 21 from being subjected to excessive tension such that the media M slips on the transport roller 21, for example.

(3) The holding force of the intermediate roller 41 is smaller than the holding force of the transport roller. That is, the intermediate roller 41 supports the media M with a smaller holding force than the transport roller 21. Therefore, it is possible to prevent the media M from being indented or otherwise scratched by the intermediate slack eliminating operation.

(4) In the preparatory operation, the control unit 50 performs a roll slack forming operation so that the transport operation is started with a slack formed between the intermediate roller 41 and the roll holding unit 31. According to such a configuration, the intermediate roller 41 is less likely to be affected by the eccentricity and inclination of the roll body 36. As a result, it is possible to suppress a decrease in the transfer accuracy of the intermediate roller 41 and, by extension, a decrease in the transfer accuracy of the transfer roller 21.

(5) In the preparatory operation, the control unit 50 executes a roll slack eliminating operation for eliminating the slack of the media M located between the intermediate roller 41 and the roll holding unit 31 before executing the roll slack forming operation. .. According to such a configuration, the slack of the media M located between the intermediate roller 41 and the roll holding portion 31 is eliminated by the roll slack eliminating operation after the transfer operation is completed. As a result, the initial slack 96 formed by the roll slack forming operation can be made less susceptible to the eccentricity and inclination of the roll body 36 during the previous roll slack forming operation. Further, by the roll slack eliminating operation, it is possible to reset the accumulation of the transport error and the accumulation of the slack amount error in the width direction for the media M located between the intermediate roller 41 and the roll holding portion 31.

The above embodiment can be modified and implemented as follows. The above-described embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
In the preparatory operation, the control unit 50 may execute the roll slack forming operation without executing the roll slack eliminating operation. In the roll slack forming operation in such a configuration, a slack amount larger than the transfer amount may be set in the preparatory operation immediately after the start of recording, and the slack amount may be the same as the transfer amount in the subsequent preparatory operation.

The control unit 50 is not limited to a configuration that determines the end of the roll slack elimination operation based on the roll slack elimination current in the roll slack elimination operation, for example, the roll slack is based on the amount of change in the rotation position of the roll holding unit 31. The end of the resolution operation may be determined.

In the preparatory operation, the control unit 50 may execute only the intermediate slack eliminating operation without executing the roll slack eliminating operation or the roll slack forming operation.
The control unit 50 may perform the roll slack forming operation in parallel with the transfer operation, or may perform the roll slack forming operation so as to straddle the preparatory operation and the transfer operation.

The holding force of the intermediate roller 41 may be the same holding force as the holding force of the transport roller 21, or may be a holding force larger than the holding force of the transport roller 21.
The holding force of the intermediate roller 41 may be variable. For example, a relative position changing mechanism capable of changing the relative position between the intermediate driving roller 41a and the intermediate driven roller 41b is provided, and the holding force of the intermediate roller 41 is variably configured by controlling the relative position changing mechanism by the control unit 50. May be done.

The control unit 50 is not limited to a configuration that determines the end of the intermediate slack elimination operation based on the intermediate slack elimination current, and determines, for example, the end of the intermediate slack elimination operation based on the amount of change in the rotation position of the intermediate drive roller 41a. You may.

The recording device 10 may be a recording device that ejects or ejects a liquid other than ink. The state of the liquid discharged as a minute amount of droplets from the recording device shall include those having a granular, tear-like, or thread-like tail. The liquid referred to here may be any material that can be ejected from the recording device. For example, the liquid may be in the state when the substance is in the liquid phase, and is a highly viscous or low-viscosity liquid, sol, gel water, other inorganic solvents, organic solvents, solutions, liquid resins, liquid metals, etc. It shall contain a fluid such as a metal melt. The liquid includes not only a liquid as a state of a substance but also a liquid in which particles of a functional material made of a solid substance such as a pigment or a metal particle are dissolved, dispersed or mixed in a solvent. Typical examples of the liquid include ink, liquid crystal, and the like as described in the above embodiment. Here, the ink includes general water-based inks, oil-based inks, and various liquid compositions such as gel inks and hot melt inks. Specific examples of the recording device include a device that injects a liquid containing materials such as electrode materials and color materials used in the manufacture of liquid crystal displays, electroluminescence displays, surface emitting displays, color filters, etc. in the form of dispersion or dissolution. There is. The recording device may be a device for injecting a bioorganic substance used for producing a biochip, a device for injecting a liquid as a sample used as a precision pipette, a printing device, a micro dispenser, or the like. The recording device is a transparent resin liquid such as an ultraviolet curable resin for forming a device that injects lubricating oil pinpointly into a precision machine such as a watch or a camera, a micro hemispherical lens used for an optical communication element, an optical lens, or the like. May be a device for injecting light onto a substrate. The recording device may be a device that injects an etching solution such as an acid or an alkali in order to etch a substrate or the like.

The recording device 10 is not limited to the serial recording method, and is a long line head in which the recording head 16 is arranged over the entire width of the media M, and droplets are simultaneously ejected over the entire width of the media M. It may be a line recording method capable of discharging.

The contents derived from the above-described embodiment and modification will be described.
The media transport device is a media transport device that transports the media drawn from the roll body, and includes a transport roller that transports the media and an intermediate roller that transports the media drawn from the roll body to the transport roller. The control unit includes a control unit that controls the drive of the transport roller and the drive of the intermediate roller, and the control unit causes the media to loosen between the transport roller and the intermediate roller by driving the intermediate roller. A transport operation of transporting the media by driving the transport roller and the intermediate roller after the formation, and an operation executed during a period from the end of the transport operation to the start of the next transport operation. By driving the intermediate roller, an intermediate slack eliminating operation of eliminating the slack of the media between the transport roller and the intermediate roller is executed.

According to the above configuration, the media is transported by the transport roller in a state where slack is formed in the media located between the transport roller and the intermediate roller. Therefore, the transport by the transport roller causes eccentricity, inclination, etc. of the roll body. It becomes less affected by. In addition, since the slack of the media located between the transfer rollers and the intermediate rollers is eliminated by the intermediate slack elimination operation after the transfer operation is completed, the transfer error generated in the intermediate rollers during the current transfer operation can be eliminated. it can. That is, according to the above configuration, the transfer by the transfer roller is not easily affected by the eccentricity and inclination of the roll body, and the intermediate roller generated in the previous transfer operation on the media located between the transfer roller and the intermediate roller. Since the influence of the transfer error on the next transfer operation is small, the transfer by the transfer roller can be performed with high accuracy.

The media transfer device includes an intermediate roller drive unit that drives the intermediate roller, and the control unit includes a drive torque acquisition unit that acquires the drive torque of the intermediate roller drive unit, and in the intermediate slack eliminating operation, the media transfer device includes a drive torque acquisition unit. When the drive torque acquired by the drive torque acquisition unit reaches the target value, the intermediate slack eliminating operation may be terminated.

According to the above configuration, it is possible to prevent excessive tension from acting on the media located between the transport roller and the intermediate roller.
In the media transfer device, the holding force of the intermediate roller may be smaller than the holding force of the transfer roller.

According to the above configuration, deformation such as indentation is less likely to occur on the media due to the drive of the intermediate roller such as the operation of eliminating the intermediate slack.
The media transfer device includes a roll drive unit that drives a roll holding unit that rotatably holds the roll body, and the control unit starts the next transfer operation after the intermediate slack eliminating operation is completed. In the period up to, the roll slack forming operation of driving the roll driving unit to form slack in the media located between the intermediate roller and the roll holding unit may be executed.

According to the above configuration, the media is conveyed by the intermediate roller in a state where slack is formed in the media located between the intermediate roller and the roll body, so that the intermediate roller is affected by the eccentricity and inclination of the roll body. It becomes difficult to receive. As a result, the accuracy of media transfer by the intermediate roller can be improved.

In the media transfer device, the control unit drives the roll drive unit between the intermediate roller and the roll holding unit after the transfer operation is completed and before the roll slack forming operation is executed. A roll slack eliminating operation for eliminating slack in the media may be executed.

According to the above configuration, the slack of the media located between the intermediate roller and the roll holding portion is eliminated by the roll slack eliminating operation after the transfer operation is completed. As a result, the slack formed by the roll slack forming operation can be made less susceptible to the eccentricity and inclination of the roll body during the previous roll slack forming operation.

The recording device includes the above-mentioned media transfer device and a recording unit that records by ejecting a liquid to the media transported by the media transfer device. According to such a configuration, the same effect as that of the above-mentioned media transfer device can be obtained.

The media transport method is a control method of a media transport device that transports the media drawn from the roll body in the transport direction, and the media transport device is drawn from the transport roller that transports the media and the roll body. An intermediate roller that conveys the media to the transfer roller is provided, and a control unit that controls the drive of the transfer roller and the drive of the intermediate roller is between the transfer roller and the intermediate roller by the drive of the intermediate roller. After forming the slack in the media, the media is transported by driving the transport roller and the intermediate roller, and the media is executed during a period from the end of the transport process to the start of the next transport process. The intermediate slack eliminating step of driving the intermediate roller to eliminate the slack of the media between the transport roller and the intermediate roller is executed. According to such a configuration, the same effect as that of the above-mentioned media transfer device can be obtained.

M ... media, 10 ... recording device, 11 ... recording unit, 12 ... transport unit, 13 ... support base, 14 ... guide shaft, 15 ... carriage, 16 ... recording head, 17 ... carriage drive mechanism, 20 ... feed mechanism, 21 ... Transfer roller, 21a ... Transfer drive roller, 21b ... Transfer driven roller, 22 ... Transfer roller drive unit, 23 ... Transfer motor, 23a ... Transfer output shaft, 24 ... Transfer transmission mechanism, 25 ... Transfer rotation detection unit, 30 ... Roll Body drive mechanism, 31 ... Roll holding unit, 31a ... Holder, 32 ... Roll drive unit, 33 ... Roll motor, 33a ... Roll output shaft, 34 ... Roll transmission mechanism, 35 ... Roll rotation detection unit, 36 ... Roll body, 40 ... Intermediate transport mechanism, 41 ... Intermediate roller, 41a ... Intermediate drive roller, 41b ... Intermediate driven roller, 42 ... Intermediate roller drive unit, 43 ... Intermediate motor, 43a ... Intermediate output shaft, 44 ... Intermediate transmission mechanism, 45 ... Intermediate rotation Detection unit, 50 ... Control unit, 51 ... CPU, 52 ... ROM, 53 ... RAM, 54 ... PROM, 55 ... ASIC, 56 ... Driver, 57 ... Bus, 61 ... Main control unit, 62 ... Conveyor motor control unit, 63 ... Roll motor control unit, 64 ... Intermediate motor control unit, 66 ... Position subtraction unit, 67 ... Position calculation unit, 68 ... Target speed calculation unit, 69 ... Speed subtraction unit, 70 ... Rotation speed calculation unit, 71 ... Timer, 72 ... Proportional term calculation unit, 73 ... Integration term calculation unit, 74 ... Differential term calculation unit, 75 ... Addition unit, 76 ... PWM output unit, 80 ... Tension control unit, 81 ... Drive current calculation unit, 82 ... Reference current calculation unit , 83 ... low pass filter, 84 ... low pass filter, 85 ... current subtraction unit, 86 ... conversion unit, 87 ... deviation calculation unit, 88 ... correction amount calculation unit, 89 ... correction unit, 95 ... slack, 96 ... initial slack, 652 , 653,654 ... Feedback section.

Claims (7)

A media transfer device that conveys media drawn from a roll body.
A transport roller that transports the media and
An intermediate roller that conveys the media drawn from the roll body to the conveying roller, and
A control unit that controls the drive of the transport roller and the drive of the intermediate roller is provided.
The control unit
A transport operation in which the media is transported by driving the transport roller and the intermediate roller after forming a slack in the media between the transport roller and the intermediate roller by driving the intermediate roller.
This operation is executed during the period from the end of the transfer operation to the start of the next transfer operation, in which the media is slackened between the transfer roller and the intermediate roller by driving the intermediate roller. A media transfer device characterized by performing an intermediate slack eliminating operation to eliminate. An intermediate roller drive unit for driving the intermediate roller is provided.
The control unit
In addition to including a drive torque acquisition unit that acquires the drive torque of the intermediate roller drive unit,
The media transfer device according to claim 1, wherein in the intermediate slack elimination operation, the intermediate slack elimination operation is terminated when the drive torque acquired by the drive torque acquisition unit reaches a target value. The media transfer device according to claim 1 or 2, wherein the holding force of the intermediate roller is smaller than the holding force of the transfer roller. A roll driving unit for driving a roll holding unit that rotatably holds the roll body is provided.
The control unit
During the period from the end of the intermediate slack eliminating operation to the start of the next conveying operation, the roll driving unit is driven to cause slack in the media located between the intermediate roller and the roll holding unit. The media transport device according to any one of claims 1 to 3, wherein the roll slack forming operation to be formed is executed. The control unit
After the transfer operation is completed, before executing the roll slack forming operation, a roll slack eliminating operation for driving the roll driving unit to eliminate the slack of the media between the intermediate roller and the roll holding unit is performed. The media transfer device according to claim 4, wherein the media transfer device is to be executed. The media transfer device according to any one of claims 1 to 5.
A recording device including a recording unit that records by ejecting a liquid to the media conveyed by the media transfer device. It is a control method of a media transfer device that conveys the media drawn from the roll body in the transfer direction.
The media transfer device is
A transport roller that transports the media and
An intermediate roller for transporting the media drawn from the roll body to the transport roller is provided.
The control unit that controls the drive of the transport roller and the drive of the intermediate roller
A transfer step of forming a slack in the media between the transfer roller and the intermediate roller by driving the intermediate roller and then transporting the media by driving the transfer roller and the intermediate roller.
A step executed during the period from the end of the transfer step to the start of the next transfer step, in which the intermediate roller is driven to loosen the media between the transfer roller and the intermediate roller. A media transfer method characterized by performing an intermediate slack elimination process and performing.