JP2017170752A - Control method for medium feeder, medium feeder, and medium processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow heat generation of a drive motor to be reduced as small as possible.SOLUTION: A control method for medium feeders 11 and 13 comprising a feed roller 31 feeding a printing medium P and a feed motor 41 driving the feed roller 31 executes a stop control step for performing control of the feed motor 41 such that a rotational position of the feed roller 31 is maintained at a target position after determining the rotational position of the feed roller 31 to reach the target position, and, in the stop control step, switches an upper limit value of a motor output value between a first threshold value and a second threshold value lower than the first threshold value and performs the control of the feed motor 41.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a control method for a medium feeding device for feeding a medium such as a print medium, a medium feeding device, and a medium processing device.

  Conventionally, as a printer, a PF roller pair that conveys a print medium, a carriage drive mechanism that mounts a print head and performs printing on a print medium that is fed by the PF roller pair, and a feed motor that drives the PF roller pair ( A device having a PF motor) and a control unit that controls a feed motor is known (see Patent Document 1). In this printer, PID control is performed to control the feed motor so that the rotational position of the PF roller pair reaches the target position.

JP 2009-73181 A

By the way, in the conventional printer, the PID control is continuously performed even after the rotational position of the PF roller pair reaches the target position. That is, even after the rotational position of the PF roller pair reaches the target position, the rotational position of the PF roller pair is maintained at the target position by continuing to input current to the PF motor at a level where the PF roller pair does not rotate. ing.
However, in the above conventional configuration, as shown in FIG. 7, the input current is gradually decreased by the PID control, so that it is necessary to maintain the rotational position of the PF roller pair at the target position. It becomes the structure which continues inputting an electric current exceeding an electric current. As a result, a current more than necessary was continuously input, and there was a problem that the feed motor generated more heat.

  An object of the present invention is to provide a control method of a medium feeding device, a medium feeding device, and a medium processing device that can reduce heat generation of a drive motor as much as possible.

  A method for controlling a medium feeding device according to the present invention is a method for controlling a medium feeding device including a roller for feeding a medium and a drive motor for driving the roller, and determines that the rotational position of the roller has reached a target position. After that, a stop control step for controlling the drive motor is executed so that the rotational position of the roller is maintained at the target position. In the stop control step, the upper limit value of the motor output value is set to the first threshold value and the first threshold value. The drive motor is controlled by switching between a second threshold value lower than the threshold value.

  The medium feeding device of the present invention includes a roller that feeds a medium, a drive motor that drives the roller, and a control unit that controls the drive motor, and the control unit determines that the rotational position of the roller has reached the target position. After that, a stop control step for controlling the drive motor is executed so that the rotational position of the roller is maintained at the target position. In the stop control step, the upper limit value of the motor output value is set to the first threshold value and the first threshold value. The drive motor is controlled by switching between a second threshold value lower than the threshold value.

  A medium processing apparatus according to the present invention includes the medium feeding device described above and a medium processing unit that performs predetermined processing on the medium during execution of the stop control step.

  In this case, the predetermined process is preferably a printing process.

  According to these configurations, as shown in FIG. 6, by appropriately switching the upper limit value of the motor output value to the second threshold value and controlling the drive motor, it is possible to avoid the input of more current than necessary. be able to. As a result, the heat generation of the drive motor can be minimized.

  In the control method for the medium feeding device, in the stop control step, the upper limit value of the motor output value is switched to the first threshold value until a predetermined time elapses, and the drive motor is controlled. It is preferable to control the drive motor by switching the upper limit value to the second threshold value.

  According to this configuration, since the upper limit value of the motor output value is switched to the second threshold value after a certain period of time has elapsed and the rotational position of the roller has been stabilized, Heat generation can be reduced.

  In this case, in the stop control step, the driving motor is subjected to PI control or PID control, and when the upper limit value of the motor output value is switched to the first threshold value, the upper limit value of the integrated output value in the PI control or PID control is set to the first value. When switching to the threshold value and switching the upper limit value of the motor output value to the second threshold value, it is preferable to switch the upper limit value of the integrated output value to the second threshold value.

  According to this configuration, not only the motor output value but also the integral output value, the integral output value that is originally accumulated is suppressed to the second threshold value by setting the upper limit value as the second threshold value. As a result, it is possible to avoid a situation in which the motor output value jumps up due to the accumulated integrated output value at the timing when the upper limit value of the motor output value is switched from the second threshold value to the first threshold value.

1 is a plan view showing a schematic configuration of a large format printer according to an embodiment of the present invention. It is the side view which showed schematic structure of the large format printer. It is the block diagram which showed the function structure of the controller. It is a graph which shows the relationship between the arbitrary rotation speeds of a roll body, and a duty value required in order to rotate a roll body. It is the block diagram which showed the structure of the feed motor control part. It is the graph which showed control of the feed motor at the time of line feed operation and printing operation. It is the graph which showed control of the feed motor at the time of line feed operation and printing operation in the conventional composition.

  Hereinafter, a method for controlling a medium feeding apparatus, a medium feeding apparatus, and a medium processing apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings. In the embodiment, a large format printer to which the method for controlling a medium feeding device, the medium feeding device, and the medium processing device of the present invention are applied is illustrated. This large format printer (medium processing apparatus) performs printing on a large format print medium that is being sent by an inkjet method while pulling out and feeding a large format print medium (medium) from a roll body. The roll body set in this large format printer is obtained by winding a long print medium around a cylindrical core in a roll shape. The print medium is recording paper, film, cloth, or the like.

  As shown in FIGS. 1 and 2, the large format printer 1 includes a medium feeding mechanism 11 that sends the printing medium P in the paper feeding direction, and a printing mechanism 12 that performs printing on the printing medium P that is sent by the medium feeding mechanism 11. (Medium processing unit) and a controller 13 (control unit) for controlling them. The large-format printer 1 performs printing on the print medium P by a serial printing method by repeating a line feed operation by the medium feed mechanism 11 and a print operation (print process) by the printing mechanism 12. The “medium feeding device” includes the medium feeding mechanism 11 and the controller 13.

  The printing mechanism 12 performs printing on a printing medium P that is fed by a feed roller 31 described later. The inkjet printing head 21, a carriage 22 that mounts the printing head 21, and the carriage 22 A reciprocating mechanism 23 that reciprocates the print head 21 and a platen 24 that faces the print head 21 are provided. The printing mechanism 12 may be configured to include a plurality of print heads 21 or may be configured to include only one print head 21.

  The print head 21 has a nozzle row (not shown) extending in the paper feed direction of the print medium P by the medium feed mechanism 11 and discharges ink from a plurality of discharge nozzles of the nozzle row. On the other hand, the reciprocating mechanism 23 reciprocates the print head 21 in a direction intersecting the paper feeding direction. Then, the printing mechanism 12 performs a printing operation on the printing medium P by driving the printing head 21 by the reciprocating mechanism 23 while moving the printing head 21 forward or backward.

  On the other hand, a plurality of suction holes 26 penetrating vertically are formed in the platen 24. A suction fan 27 is provided below the platen 24. Then, when the suction fan 27 is operated, the inside of the suction hole 26 is set to a negative pressure, and the print medium P on the platen 24 is sucked and held. In the present embodiment, a printing operation is performed on the print medium P while the print medium P is sucked and held on the platen 24.

  The medium feeding mechanism 11 includes a roll holding unit 32 that holds the roll body R around which the printing medium P is wound, and a feeding roller 31 (roller) that feeds the printing medium P while pulling out the printing medium P from the roll body R. Further, the medium feeding mechanism 11 includes a roll driving unit 38 that rotationally drives the roll body R, and a feeding roller driving unit 36 that drives the feeding roller 31.

  The feed roller 31 is composed of a nip roller composed of a drive roller 31a and a driven roller 31b. That is, the driving roller 31a and the driven roller 31b rotate and feed the print medium P while being sandwiched between them. The driving roller 31a and the driven roller 31b also serve to hold the print medium P when the print medium P is not being rotationally fed. The drive roller 31 a has a feed input gear 31 c that receives power from the feed roller drive unit 36.

  The feed roller drive unit 36 includes a feed motor 41 (drive motor) serving as a power source (drive source), a feed gear train 42 that transmits the power of the feed motor 41 to the feed roller 31, and the rotation position and rotation of the feed roller 31. A feed rotation detection unit 43 that detects a direction. The feed motor 41 is, for example, a DC motor. The feed gear train 42 is connected to a feed input gear 31c provided on the drive roller 31a. Then, the power from the feed motor 41 is transmitted to the feed input gear 31c via the feed gear train 42, whereby the drive roller 31a rotates and the driven roller 31b rotates accordingly. Thus, the feed roller 31 is rotationally driven by the power of the feed motor 41.

  The feed rotation detector 43 detects the rotation position and rotation direction of the drive roller 31a. Specifically, the feed rotation detection unit 43 is configured by a rotary encoder provided with a disk-like scale provided on the output shaft of the feed motor 41 and a photo interrupter. That is, the feed rotation detection unit 43 detects the rotation position and the rotation direction of the drive roller 31a by detecting the rotation position and the rotation direction of the output shaft of the feed motor 41.

  The roll holding part 32 includes a pair of rotation holders 32a that hold the roll body R, and holder support parts (not shown) that rotatably support the pair of rotation holders 32a. The pair of rotation holders 32a are respectively inserted into both ends of the core of the roll body R, and hold the roll body R from both sides. One of the pair of rotation holders 32 a has a roll input gear 32 b that receives power from the roll drive unit 38.

  The roll drive unit 38 includes a roll motor 51 serving as a power source, a roll gear train 52 that transmits the power of the roll motor 51 to the rotation holder 32a, and a roll rotation detection unit 53 that detects a rotation position and a rotation direction of the roll body R. . The roll motor 51 is, for example, a DC motor. The roll gear train 52 is connected to the roll input gear 32b of the rotation holder 32a that holds the roll body R. Then, the power from the roll motor 51 is transmitted to the roll input gear 32b via the roll gear train 52, whereby the rotation holder 32a provided with the roll input gear 32b rotates, and the roll held by this The body R rotates. Thus, the roll body R is rotationally driven by the power of the roll motor 51.

  The roll rotation detection unit 53 detects the rotation position and rotation direction of the roll body R. Specifically, the roll rotation detection unit 53 is configured by a rotary encoder including a disc scale provided on the output shaft of the roll motor 51 and a photo interrupter. That is, the roll rotation detection unit 53 detects the rotation position and rotation direction of the roll body R by detecting the rotation position and rotation direction of the output shaft of the roll motor 51.

  The controller 13 controls each part of the large format printer 1. Specifically, the controller 13 includes a CPU (Central Processing Unit) 71, a ROM (Read Only Memory) 72, a RAM (Random Access Memory) 73, a PROM (Programmable ROM) 74, and an ASIC (Application Specific Integrated Circuit). ) 75, a motor driver 76, and a bus 77. Each pulse signal from the feed rotation detection unit 43 and the roll rotation detection unit 53 is input to the controller 13.

  In the large-format printer 1 configured as described above, when a print job execution command is received, the printing medium P is printed by the printing mechanism 12 by the printing operation (main scanning) and the medium feeding mechanism 11 by the printing width of the printing mechanism 12. A print image is formed by alternately and repeatedly performing a line feed operation (sub-scanning). During the printing operation, the medium feeding mechanism 11 (mainly the feeding roller 31) holds the printing medium P so as not to be displaced in the medium feeding direction. That is, a printing operation is performed on the print medium P while the print medium P is held by the medium feeding mechanism 11. Although details will be described later, the present embodiment has a configuration that reduces the heat generation of the feed motor 41 when the print medium P is held.

  Next, the functional configuration of the controller 13 will be described with reference to FIG. As shown in FIG. 3, the controller 13 includes a main control unit 81, a feed motor control unit 82, and a roll motor control unit 84. Each of these functional units is realized by cooperation of hardware configuring the controller 13 and software stored in a memory such as the ROM 72.

  The main control unit 81 gives a command to the feed motor control unit 82 and the roll motor control unit 84. The main control unit 81 drives the feed motor 41 and the roll motor 51 independently, or the feed motor control unit 82 and the roll motor control unit 84 so as to drive the feed motor 41 and the roll motor 51 synchronously. Can be given a command.

  The feed motor control unit 82 drives and controls the feed motor 41 through PWM (Pulse Width Modulation) control via the motor driver 76. The feed motor control unit 82 outputs the PID-controlled duty value to the motor driver 76 based on the rotation speed and rotation position of the drive roller 31 a detected by the feed rotation detection unit 43.

  The roll motor control unit 84 drives and controls the roll motor 51 by PWM control via the motor driver 76. The roll motor control unit 84 performs arithmetic processing for obtaining the motor output value, and outputs the calculated motor output value to the motor driver 76.

ここで、ｒはロール体Ｒの半径、Ｍはロールギア列５２による減速比、Duty(max)はデューティ値の最大値、Ｔｓはロールモーター５１の起動トルク、ａおよびｂは後述するメジャーメント動作により算出される係数である。 In this calculation process, as shown in the equation (1), basically, the feed roller 31 and the roll body R are derived from Duty (ro) which is a duty value required to rotate the roll body R at the rotation speed V. The motor output value Dx is obtained by subtracting Duty (f) which is a duty value (hereinafter referred to as “tension control value”) necessary for applying a predetermined tension F to the print medium P between the two.

Here, r is the radius of the roll body R, M is the reduction ratio by the roll gear train 52, Duty (max) is the maximum duty value, Ts is the starting torque of the roll motor 51, and a and b are the measurement operations described later. This is a calculated coefficient.

  Here, the measurement operation will be described with reference to FIG. As shown in FIG. 4, in the measurement operation, first, the controller 13 drives the roll motor 51 so that the roll body R rotates at a low rotation speed Vl with the feed motor 41 stopped driving. Then, when the rotational speed of the roll body R is stabilized at the rotational speed Vl, the controller 13 acquires the duty value output to the roll motor 51 at that time as Duty (ro) _l. Next, the controller 13 drives the roll motor 51 so as to rotate to the roll body R at a high rotational speed Vh in a state where the driving of the feed motor 41 is stopped. Then, the controller 13 acquires the duty value Duty (ro) _h corresponding to the high-speed rotation speed Vh in the same manner as when acquiring the duty value Duty (ro) _l corresponding to the low-speed rotation speed Vl.

By substituting these values into equation (2), simultaneous equations relating to coefficients a and b can be obtained.
Duty (ro) = a × V + b (2)
By solving the obtained simultaneous equations, the coefficients a and b are determined and reflected in the equation (1).

  Next, the configuration of the feed motor control unit 82 will be described with reference to FIG. As shown in FIG. 5, the feed motor control unit 82 includes a speed PID control unit 101, a position PID control unit 102, a control switching unit 103, and an upper limit switching unit 104.

The speed PID control unit 101 performs PID control of the feed motor 41 so that the rotation speed of the drive roller 31a becomes the target speed input from the main control unit 81 (speed PID control). Specifically, the speed PID control unit 101 first calculates a speed error ΔV between the current rotation speed detected by the feed rotation detection unit 43 and the target speed input from the main control unit 81. Then, based on the calculated speed error ΔV, each control value Q is calculated by the following equations (3) to (5).
QP (j) = ΔV (j) × Kp (3)
QI (j) = QI (j−1) + ΔV (j) × Ki (4)
QD (j) = {ΔV (j) −ΔV (j−1)} × Kd (5)
Here, j is time, Kp is a proportional gain, Ki is an integral gain, and Kd is a differential gain.

  When each control value is calculated, the calculated control values are summed, and the summed control value Qpid is set as a motor output value. That is, a PWM signal having a duty value corresponding to the control value Qpid is output to the motor driver 76. The motor driver 76 drives the feed motor 41 by PWM control based on this PWM signal.

The position PID control unit 102 performs PID control of the feed motor 41 so that the rotation position of the drive roller 31a becomes the target position (target rotation amount) input from the main control unit 81 (position PID control). Specifically, the position PID control unit 102 first calculates a position error between the current rotation position of the feed roller 31 detected by the feed rotation detection unit 43 and the target position commanded from the main control unit 81. . Next, the deviation ΔH is calculated by multiplying the calculated position error by a predetermined position gain and subtracting the current rotation speed detected by the feed rotation detection unit 43. Then, based on the calculated deviation ΔH, each control value Q is calculated by the following equations (6) to (8).
QP (j) = ΔH (j) × Kp (6)
QI (j) = QI (j−1) + ΔH (j) × Ki (7)
QD (j) = {ΔH (j) −ΔH (j−1)} × Kd (8)

When each control value is calculated, the calculated control values are summed, and a current value corresponding to the summed control value Qpid is set as a motor output value. That is, a PWM signal having a duty value corresponding to the current value is output to the motor driver 76. The motor driver 76 drives the feed motor 41 by PWM control based on this PWM signal.
In the position PID control unit 102, an upper limit value is set for each of the motor output value and the integral output value (current value corresponding to the control value QI (j)). That is, when the absolute value of the calculated motor output value exceeds the upper limit value, the motor output value is set as the upper limit value. When the absolute value of the calculated integral output value exceeds the upper limit value, the control value corresponding to the upper limit value is set as the control value QI (j).

  In response to a command from the main control unit 81, the control switching unit 103 controls the feed motor 41 by speed PID control by the speed PID control unit 101 or position PID control by the position PID control unit 102. Switch.

  Upon receiving a command from the main control unit 81, the upper limit switching unit 104 switches the upper limit value of the motor output value and the integral output value in the position PID control unit 102 between the first threshold value and the second threshold value. The first threshold is a default threshold. In this example, the first threshold is set to a value of 500 mA or more and 600 mA or less. On the other hand, the second threshold value is a predetermined low value that is lower than the first threshold value and necessary for maintaining the rotational position of the feed roller 31 at the current position. In this example, the second threshold is set to a value between 200 mA and 300 mA.

  Next, with reference to FIG. 6, the control of the feed motor 41 during the line feed operation and the printing operation will be described. The line feed operation is composed of an acceleration section, a constant speed section, and a deceleration section. In this embodiment, at the time of a line feed operation, speed PID control is performed halfway through the deceleration section, and thereafter, position PID control is performed. (See FIG. 6). That is, the main control unit 81 controls the feed motor 41 by switching to the speed PID control by the speed PID control unit 101 by the control switching unit 103 until the middle of the deceleration section. Further, the main control unit 81 thereafter switches to the position PID control by the position PID control unit 102 by the control switching unit 103 and controls the feed motor 41 so that the rotational position of the feed roller 31 reaches the target position.

  On the other hand, position PID control is performed during the printing operation. That is, the main control unit 81 switches to the position PID control by the position PID control unit 102 by the control switching unit 103 and controls the feed motor 41 so that the rotation position of the feed roller 31 is maintained at the target position (stop control). Step). That is, after determining that the rotational position of the feed roller 31 has reached the target position by the line feed operation, the feed motor 41 is controlled by the position PID control so that the rotational position of the feed roller 31 is maintained at the target position. . Note that the position PID control during the printing operation uses gain values (position gain, proportional gain, integral gain, and differential gain) that are different from the position PID control during the line feed operation.

At this time, the upper limit value of the motor output value and the integral output value is switched to the first threshold value until a predetermined time t has elapsed since it is determined that the rotational position of the feed roller 31 has reached the target position. Then, the upper limit value of the integral output value is switched to the second threshold value to control the feed motor 41 (see FIG. 6). The fixed time t is the time from when the rotational position of the feed roller 31 reaches the target position until the rotational position is stabilized. That is, the main control unit 81 switches the upper limit value of the motor output value and the integral output value to the first threshold value until the rotation position of the feed roller 31 is stabilized by the upper limit switching unit 104, and the feed motor 41 is changed. After the rotational position of the feed roller 31 is stabilized, the upper limit value of the motor output value and the integral output value is switched to the second threshold value, and the feed motor 41 is controlled.
By such control, the printing medium P is held by the feed roller 31 so as not to be displaced in the medium feeding direction during the printing operation. That is, during such control of the feed roller 31 (during execution of the stop control step), a printing operation is performed on the print medium P held by the feed roller 31.

  As described above, according to the above-described embodiment, it is possible to avoid the input of more current than necessary by controlling the drive motor by switching the upper limit value of the motor output value to the second threshold value. Thereby, the heat generation of the feed motor 41 can be reduced as much as possible.

  Further, since the upper limit value of the motor output value is switched to the second threshold value after the fixed time t has elapsed and the rotational position of the feed roller 31 is stabilized, the feed motor is not reduced without reducing the stop accuracy of the feed roller 31. The heat generation of 41 can be reduced. For example, when the rotational position of the feed roller 31 is not stable due to a load from the print medium P, the upper limit value of the motor output value is switched to the second threshold value, and when the rotational position of the feed roller 31 is stabilized, the upper limit value of the motor output value By switching to the second threshold value, it is possible to avoid a situation where the stopping accuracy of the feed roller 31 is lowered.

  Further, when the upper limit value of the motor output value is switched to the first threshold value, the upper limit value of the integrated output value is switched to the first threshold value, and when the upper limit value of the motor output value is switched to the second threshold value, the upper limit value of the integrated output value is changed. Since the configuration is switched to the second threshold value, the accumulated integrated output value can be suppressed to the second threshold value. As a result, it is possible to avoid a situation in which the motor output value jumps up due to the accumulated integrated output value at the timing when the upper limit value of the motor output value is switched from the second threshold value to the first threshold value.

  In the above embodiment, the feed motor 41 is PID-controlled, but the feed motor 41 may be PI-controlled. As a result, the feed motor 41 may be configured to perform feedback control other than PID control and PI control.

Moreover, in the said embodiment, although this invention was applied to the structure which controls the feed motor 41, it is not restricted to this. For example, the medium feeding mechanism 11 further includes an intermediate roller disposed between the feeding roller 31 and the roll body R and an intermediate motor that drives the intermediate roller, and the present invention is configured to control this intermediate motor. May be applied.
As a result, you may apply this invention to the structure which controls the roll motor 51 and the carriage motor (illustration omitted) which drives the reciprocating mechanism 23. FIG.

  In the above embodiment, the present invention is applied to the large format printer 1 having the printing mechanism 12 that performs the printing process on the printing medium P. However, the medium processing unit that performs a predetermined process other than the printing process is provided on the medium. The present invention may be applied to a medium processing apparatus.

  DESCRIPTION OF SYMBOLS 1 ... Large format printer, 11 ... Medium feed mechanism, 12 ... Printing mechanism, 13 ... Controller, 31 ... Feed roller, 41 ... Feed motor, P ... Print medium.

Claims (6)

A roller for feeding the medium;
A control method of a medium feeding device comprising a drive motor for driving the roller,
After determining that the rotational position of the roller has reached the target position, a stop control step is performed to control the drive motor so that the rotational position of the roller is maintained at the target position.
In the stop control step, the drive motor is controlled by switching the upper limit value of the motor output value between a first threshold value and a second threshold value lower than the first threshold value. Control method of the device. In the stop control step,
Until an elapse of a certain time, the upper limit value of the motor output value is switched to the first threshold value to control the drive motor,
2. The method of controlling a medium feeding device according to claim 1, wherein after the predetermined time elapses, an upper limit value of the motor output value is switched to the second threshold value to control the drive motor. In the stop control step,
In addition to PI control or PID control of the drive motor,
When switching the upper limit value of the motor output value to the first threshold value, the upper limit value of the integral output value in the PI control or the PID control is switched to the first threshold value,
3. The medium feeding device control according to claim 1, wherein when the upper limit value of the motor output value is switched to the second threshold value, the upper limit value of the integral output value is switched to the second threshold value. Method. A roller for feeding the medium;
A drive motor for driving the roller;
A control unit for controlling the drive motor,
The control unit is
After determining that the rotational position of the roller has reached the target position, a stop control step is performed to control the drive motor so that the rotational position of the roller is maintained at the target position.
In the stop control step, the drive motor is controlled by switching the upper limit value of the motor output value between a first threshold value and a second threshold value lower than the first threshold value. apparatus. A medium feeding device according to claim 4;
A medium processing apparatus comprising: a medium processing unit that performs predetermined processing on the medium during execution of the stop control step.   The medium processing apparatus according to claim 5, wherein the predetermined process is a printing process.

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