JP2009256095A - Printer and printing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printer capable of finely controlling tension generated when a medium is carried between a first motor and a second motor, and a printing method. <P>SOLUTION: The printer comprises the first motor giving driving force for rotating a rolling body around which the medium is wound; a second motor giving the driving force for driving a carrying drive roller which is provided in a supplying direction of the medium on a downstream side to the rolling body and carries the medium; and a control portion controlling the first motor to make the tension generated in the medium between the rolling body and the carrying drive roller become not more than a predetermined value, when the first motor and the second motor are driven together to carry the medium. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a printing apparatus and a printing method.

Among the ink jet printers, there is a type that uses a large paper having a paper size of A2 or larger. In such large-format ink jet printers, so-called roll paper (hereinafter, a so-called roll paper around which the paper is wound is used as a roll body and a portion pulled out from the roll body is used as paper) is used in addition to the cut paper. There are many cases. At present, the paper is drawn from the roll body by a paper feed motor (PF motor). At this time, the PF motor is controlled and driven by PID control. As a printer using such a roll body, there is one disclosed in Patent Document 1. Further, there are printers that perform PID control as shown in Patent Documents 2 to 4.
JP 2007-290866 A JP 2006-240212 A JP 2003-79177 A JP 2003-48351 A

  The roll body in a large-format printer is heavy, so that the load when pulling out the paper from the roll body is large. Therefore, there is a possibility that the paper breaks only by driving from the PF motor. Therefore, a model has been developed in which a roll motor for rotating the roll body is provided, and the roll motor is driven together with the PF motor to pull out the paper.

  Here, since the large-sized roll body has a large width dimension, as the paper is pulled out, a so-called skew tends to be generated in which the longitudinal direction of the paper is gradually inclined with respect to the original drawing direction. Therefore, it is necessary to eliminate the skew as appropriate. On the other hand, it has been studied that the PF motor and the roll motor are driven simultaneously and the skew is eliminated by the simultaneous driving. However, in the simultaneous driving, the tension between the PF motor and the roll motor is reduced. When it becomes large, there is a problem that the paper breaks.

  The present invention has been made based on the above circumstances, and its object is to satisfactorily control the tension generated when a medium such as roll paper is conveyed between the first motor and the second motor. It is an object of the present invention to provide a printing apparatus and a printing method that can be used.

The main invention for achieving the above object is:
A first motor for providing a driving force for rotating a roll body around which a medium is wound;
A second motor for supplying a driving force for driving a transport driving roller for transporting the medium, which is a transport driving roller provided on the downstream side of the roll body along the supply direction of the medium;
When the medium is transported by driving both the first motor and the second motor, the first tension is applied to the medium between the roll body and the transport driving roller so as to be not more than a predetermined value. A control unit for controlling the motor;
Is a printing apparatus.

  Other features of the present invention will become apparent from the present specification and the accompanying drawings.

  At least the following matters will become clear from the description of the present specification and the accompanying drawings.

A first motor for providing a driving force for rotating a roll body around which a medium is wound;
A second motor for supplying a driving force for driving a transport driving roller for transporting the medium, which is a transport driving roller provided on the downstream side of the roll body along the supply direction of the medium;
When the medium is transported by driving both the first motor and the second motor, the first tension is applied to the medium between the roll body and the transport driving roller so as to be not more than a predetermined value. A control unit for controlling the motor;
A printing apparatus comprising:
By doing in this way, the first motor and the second motor are both driven by the control unit, and the medium transport operation is realized. In addition, the control unit controls the first motor so that the tension applied to the medium between the roll body and the conveyance driving roller is equal to or less than a predetermined value. And it can prevent that a big tension acts on a medium, and can prevent malfunctions, such as a medium fracture. In addition, the medium can be prevented from being skewed by being transported in a state where tension is applied to the medium.

The controller may control the first motor and the second motor so that the medium is conveyed in a direction opposite to the supply direction in order to wind the medium around the roll body. desirable.
By doing so, it is possible to realize the operation of winding the medium with the roll body, and it is possible to satisfactorily eliminate the skew generated in the medium by this winding operation.

Further, the control unit compares a control value output from an integration element in PID control with a speed fluctuation threshold that varies according to the conveyance speed of the medium and that gives a predetermined tension. When the control value exceeds the speed fluctuation threshold value, it is desirable to perform correction for changing the control value to the speed fluctuation threshold value.
By doing in this way, the final output value in PID control is calculated | required in the state in which the control value output from an integral element does not exceed the speed fluctuation | variation threshold value which provides predetermined tension. And it can prevent that a big tension acts on a medium, and can prevent that a medium breaks.

The control unit is a speed fluctuation threshold that varies according to a total value of control values output from a proportional element, an integral element, and a derivative element in PID control, and a conveyance speed of the medium. It is desirable to compare with a given speed fluctuation threshold value, and to correct the total value to the speed fluctuation threshold value when the total value exceeds the speed fluctuation threshold value.
By doing in this way, the total value which totaled each control value will be in the state which does not exceed the speed fluctuation | variation threshold value which provides predetermined tension | tensile_strength. And it can prevent that a big tension acts on a medium, and can prevent that a medium breaks.

The controller may start driving the first motor and the second motor simultaneously, or start driving the first motor before driving the second motor.
By doing so, it is possible to satisfactorily prevent the slack from occurring at the time when the first motor is driven.

In addition, the control unit controls the first motor and the second motor so that the medium conveyance speed by driving the first motor is faster than the medium conveyance speed by driving the second motor. It is desirable to control.
By doing in this way, the tension | tensile_strength resulting from the difference in the feeding amount between a 1st motor and a 2nd motor is provided to a medium. Therefore, it is possible to satisfactorily eliminate the skew generated in the medium when the medium is wound.

The relationship between the control value for driving the first motor and the rotational speed of the first motor with respect to the control value is expressed by a linear expression, and the primary expression rotates the first motor at the first rotational speed. It is desirable to obtain the first control value when the rotation is performed and the second control value when the rotation is performed at the second rotation speed.
By doing so, it becomes possible to obtain a control value that realizes a desired rotational speed by removing individual differences between motors.

In addition, the primary expression is the first control value when the first control value is a value within a first predetermined range when the first rotation value is rotated at the first rotation speed, and the second rotation speed. It is desirable that the second control value is obtained based on the second control value when the second control value is a value within the second predetermined range.
By doing in this way, it becomes possible to obtain a linear expression excluding the case where the first control value and the second control value are abnormal values.

Further, the first predetermined range is a control value for the first motor when the roll body at the first weight and the roll body at the minimum weight and the roll body at the maximum weight are rotated. And the second predetermined range is relative to the first motor when rotating the roll body at the second rotation speed and the minimum weight and the roll body at the maximum weight. It is desirable to be obtained based on the control value.
By doing so, the first predetermined range and the second predetermined range can be obtained, and the abnormal first control value and second control value can be excluded.

Further, the linear expression is obtained based on the first control value and the second control value when the difference between the second control value and the first control value is within a predetermined range. Is desirable.
By doing in this way, it becomes possible to obtain a linear expression excluding the case where the first control value and the second control value are abnormal values.

A first motor for providing a driving force for rotating the roll body around which the medium is wound;
A second motor for supplying a driving force for driving a transport driving roller for transporting the medium, which is a transport driving roller provided on the downstream side of the roll body along the supply direction of the medium;
When the first motor and the second motor are driven together to transport the medium, the control of the first motor is performed so that the tension generated between the roll body and the transport driving roller is less than a predetermined value. A control unit for performing
A fluid ejecting head that ejects fluid to the medium;
A printing apparatus comprising:
By doing so, in a printing apparatus of a type in which the medium is pulled out from the roll body, it is possible to prevent a large tension from acting on the medium, and it is possible to prevent problems such as breakage of the medium. In addition, the medium can be prevented from being skewed by being transported in a state where tension is applied to the medium.

A first motor that applies a driving force for rotating the roll body around which the medium is wound; and a conveyance driving roller that is provided on the downstream side in the medium supply direction and conveys the medium. And driving a second motor that gives a driving force of
Controlling the first motor so that the tension generated between the roll body and the transport drive roller is below a predetermined level;
Including printing method.
By doing in this way, both the 1st motor and the 2nd motor are driven, and the conveyance operation of a medium is realized. In addition, the first motor is controlled so that the tension applied to the medium between the roll body and the transport driving roller is equal to or less than a predetermined value. And it can prevent that a big tension acts on a medium, and can prevent malfunctions, such as a medium fracture. In addition, the medium can be prevented from being skewed by being transported in a state where tension is applied to the medium.

=== Embodiment ===
Hereinafter, a printer 10 as a printing apparatus according to an embodiment and a drive control method will be described with reference to FIGS. 1 to 11. Note that the printer 10 according to the present embodiment is a printer for printing large-sized paper having a size of, for example, JIS standard A2 or larger. The printer in this embodiment is an ink jet printer. However, the ink jet printer may be an apparatus that employs any ejection method as long as the apparatus is capable of printing by ejecting ink.

  In the following description, the lower side refers to the side where the printer 10 is installed, and the upper side refers to the side away from the installed side. Further, the side on which the paper P is supplied will be described as a feeding side (rear end side), and the side on which the paper P is discharged will be described as a paper discharge side (front side).

<Schematic Configuration of Printer 10>
As shown in FIG. 1, the printer 10 includes a pair of leg portions 11 and a main body portion 20 supported by the leg portions 11. The leg portion 11 is provided with a support column 12, and a rotatable caster 13 is attached to the caster support portion 14. Therefore, the printer 10 can be moved freely by the user.

  Various types of internal devices are mounted on the main body 20 in a state of being supported by a chassis (not shown), and these are covered with an external case 21. As shown in FIG. 2, the main body 20 is provided with a roll drive mechanism 30, a carriage drive mechanism 40, and a paper transport mechanism 50 as a drive system using a DC motor. Among these, the roll drive mechanism 30 is provided in the roll mounting part 22 present in the main body part 20. As shown in FIG. 1, the roll mounting portion 22 is provided on the back side and the upper side of the main body portion 20, and by opening an opening / closing lid 23 that is one element constituting the outer case 21 described above, A roll body RP is mounted inside the roll body RP, and the roll body RP can be rotationally driven by the roll drive mechanism 30.

  Moreover, the roll drive mechanism 30 for rotating the roll body RP has a rotation holder 31, a gear wheel train 32, a roll motor 33, and a rotation detector 34, as shown in FIGS. ing. Among these, the rotation holders 31 are inserted from both ends of the hollow hole RP1 provided in the roll body RP, and a pair of rotation holders 31 are provided to support the roll body RP from both ends. The roll motor 33 corresponds to the first motor. The roll motor 33 applies a driving force (rotational force) via a gear train 32 to a rotary holder 31 a located on one end side of the pair of rotary holders 31. Furthermore, the rotation detection unit 34 uses a rotary encoder in the present embodiment. Therefore, the rotation detection unit 34 includes a disk-shaped scale 34a and a rotary sensor 34b. The disk-shaped scale 34a has a light-transmitting part that transmits light and a light-shielding part that blocks light transmission at regular intervals along the circumferential direction. The rotary sensor 34b includes a light emitting element (not shown), a light receiving element (not shown), and a signal processing circuit (not shown) as main components.

  In the present embodiment, pulse signals (A-phase ENC signal and B-phase ENC signal) whose phases are different from each other by 90 degrees as shown in FIG. 4 are input to the control unit 100 by the output from the rotary sensor 34b. Is done. Therefore, it is possible to detect whether the roll motor 33 is in the normal rotation state or the reverse rotation state by the progress / delay of the phase.

  The main body 20 is provided with a carriage drive mechanism 40. The carriage drive mechanism 40 includes a carriage 41 that is a part of components of the ink supply / ejection mechanism, a carriage shaft 42, and other carriage motors and belts (not shown).

  Among these, the carriage 41 includes an ink tank 43 for storing ink of each color (corresponding to fluid). The ink tank 43 is connected to the front side of the main body 20 via a tube (not shown). Ink can be supplied from an ink cartridge (not shown) fixedly provided on the printer. Further, as shown in FIG. 2, a print head 44 (corresponding to a fluid ejecting head) capable of ejecting ink droplets is provided on the lower surface of the carriage 41. The print head 44 is provided with a nozzle row (not shown) associated with each ink, and a piezo element (not shown) is arranged in the nozzle constituting the nozzle row. By operating the piezo element, it is possible to eject ink droplets from the nozzles at the end of the ink passage.

  The carriage 41, the ink tank 43, a tube (not shown), the ink cartridge, and the print head 44 constitute an ink supply / ejection mechanism. The print head 44 is not limited to a piezo drive system using a piezo element. For example, a heater system that heats ink with a heater and uses the generated foam force, a magnetostriction system that uses a magnetostrictive element, and a mist that is controlled by an electric field. A mist method or the like may be employed. The ink filled in the ink cartridge / ink tank 43 may be mounted with any kind of ink such as dye-based ink / pigment-based ink.

As shown in FIGS. 2, 5, and the like, the sheet transport mechanism 50 includes a transport roller pair 51, a gear wheel train 52, a PF motor 53, and a rotation detection unit 54. The conveyance roller pair 51 includes a conveyance driving roller 51a and a conveyance driven roller 51b, and a roll body RP is interposed between them.
A sheet P (corresponding to a roll sheet) drawn from the sheet can be held. Further, the PF motor 53 applies a driving force (rotational force) to the transport driving roller 51a via the gear wheel train 52. Furthermore, the rotation detection unit 54 uses a rotary encoder in the present embodiment, and includes a disk-like scale 54a and a rotary sensor 54b, as shown in the above-described rotation detection unit 34, as shown in FIG. A pulse signal can be output.

  Further, a platen 55 is provided on the downstream side (sheet discharge side) of the pair of conveying rollers 51, and the sheet P is guided on the platen 55. Further, the print head 44 is disposed on the platen 55 so as to face the platen 55. A suction hole 55 a is formed in the platen 55. On the other hand, the suction hole 55a is provided so as to be able to communicate with the suction fan 56, and when the suction fan 56 is operated, air is sucked from the print head 44 side through the suction hole 55a. As a result, when the sheet P exists on the platen 55, the sheet P can be sucked and held. In addition, the printer 10 includes other various sensors such as a paper width detection sensor that detects the width of the paper P.

<Regarding the control unit>
Next, the control unit 100 will be described with reference to FIGS. The control unit 100 is a part that performs various controls. The control unit 100 is a part for realizing PID control as described later. The control unit 100 includes outputs such as the above-described rotary sensors 34b and 54b, a linear sensor (not shown), a paper width detection sensor (not shown), a gap detection sensor (not shown), and a power switch for turning on / off the printer 10. A signal is input.

  As shown in FIG. 2, the control unit 100 includes a CPU 101, a ROM 102, a RAM 103, a PROM 104, an ASIC 105, a motor driver 106, and the like, and these are connected via a transmission path 107 such as a bus. The control unit 100 is connected to the computer COM. The hardware and software and / or data stored in the ROM 102 or PROM 104 cooperate with each other, or a circuit or component for performing a specific process is added, as shown in the block diagram of FIG. The main control unit 110, the roll motor control unit 120, and the PF motor control unit 130 are realized.

  Of these, the main control unit 110 provides both the roll motor control unit 120 and the PF motor control unit 130 to realize synchronous drive (synchronous drive) of the roll motor 33 and the PF motor 53 as will be described later. Give a command to it. Further, both the roll motor control unit 120 and the PF motor control unit 130 have PID calculation units 140a and 140b (hereinafter simply referred to as the PID calculation unit 140 when it is not necessary to distinguish between the two). Is realized. Further, the roll motor control unit 120 is provided with an output correction unit 121 in addition to the above-described PID calculation unit 140a. In the following description, since the two PID calculation units 140a and 140b are basically common, the block diagram of these PID calculation units 140a and 140b will be described first based on FIG. The relationship between the PID calculation unit 140a and the output correction unit 121 in the roll motor control unit 120 will also be described. Note that the portion surrounded by the broken line in FIG. 7 (which forms part of the output correction unit 121) is realized only by the roll motor control unit 120 as described above.

  As shown in FIG. 7, the PID calculation unit 140 includes a position calculation unit 141, a speed calculation unit 142, a first subtraction unit 143, a target speed generation unit 144, a second subtraction unit 145, and a proportional element 146. , Integral element 147, differential element 148, integral correction unit 149 (implemented if necessary), addition unit 150, final output correction unit 151 (realized if necessary), PWM signal output unit 152, And a timer 153.

  Among these components, the integral correction unit 149 and the final output correction unit 151 are components corresponding to some elements of the output correction unit 121 described above, and are realized only by the roll motor control unit 120. . Further, it is sufficient that either one of the integration correction unit 149 and the final output correction unit 151 is selectively realized. That is, in the block diagram of FIG. 6, when the integral correction unit 149 is realized, the final output correction unit 151 is not necessary, and when the final output correction unit 151 is realized, the integration correction unit 149 is not necessary. . However, a configuration including both the integral correction unit 149 and the final output correction unit 151 may be employed.

  Among these, the position calculator 141 calculates the feed amount of the paper P by counting the edges of the output signal (see FIG. 4) that is a rectangular wave input from the rotary sensors 34b and 54b. Further, the speed calculation unit 142 counts the edges of the output signal that is a rectangular wave input from the rotary sensors 34b and 54b, and also receives a signal related to the time (cycle) measured by the timer 153. Then, the feeding speed of the paper P is calculated based on the counted edge and time (cycle).

  Further, the first subtraction unit 143 is based on the information on the feed amount (current position) output from the position calculation unit 141 and the information on the target position (target stop position) output from the memory such as the ROM 102 or the PROM 104. The position deviation is calculated by subtracting the current position from the target position (target stop position). Information on the positional deviation output from the first subtraction unit 143 is input to the target speed generation unit 144. Then, the target speed generation unit 144 outputs information regarding the target speed according to the position deviation. Note that the information regarding the target speed relates to a speed table as shown in FIG. As shown in FIG. 8, there are two speed tables, a speed table Roll for the roll motor 33 and a speed table PF for the PF motor 53.

The second subtracting unit 145 subtracts the feed speed (current speed) of the current motor (roll motor 33 or PF motor 53) from the target speed to calculate the speed deviation ΔV, and the proportional element 146, the integral element 147, and the derivative. Each is output to element 148. The proportional element 146, the integral element 147, and the derivative element 148 calculate the following proportional control value QP, integral control value QI, and differential control value QD based on the input speed deviation ΔV.
QP (j) = ΔV (j) × Kp (Expression 1)
QI (j) = QI (j−1) + ΔV (j) × Ki (Expression 2)
QD (j) = {ΔV (j) −ΔV (j−1)} × Kd (Formula 3)
Here, j is time, Kp is a proportional gain, Ki is an integral gain, and Kd is a differential gain.

  In the present embodiment, the integral correction unit 149 compares the integral control value QI output from the integral element 147 with the speed variation threshold value Dx. If the result of this comparison is | QI | <Dx, the output from the integration correction unit 149 to the addition unit 150 is set to QI which is an integration control value. If the result of the above comparison is | QI | ≧ Dx, the output from the integral correction unit 149 to the addition unit 150 is set to Dx which is a speed fluctuation threshold value. | QI | is the absolute value of QI.

  When the integration correction unit 149 is not realized, the output from the integration element 147 is input to the addition unit 150.

  When the integration correction unit 149 is not realized, the addition unit 150 adds the control values output from the proportional element 146, the integration element 147, and the differentiation element 148, and sums the control values obtained by the addition (total) Value; Qpid) is output to the PWM signal output unit 152 (or the final output correction unit 151). Further, when the integration correction unit 149 is realized, the addition unit 150 adds each control value output from the proportional element 146 and the differentiation element 148 and the control value output from the integration correction unit 149, The sum (Qpid) of the control values obtained by the addition is output to the PWM signal output unit 152.

  In the present embodiment, final output correction unit 151 compares control value Qpid output from addition unit 150 with speed fluctuation threshold value Dx. If the result of this comparison is | Qpid | <Dx, the output from the adder 150 to the PWM signal output unit 152 is set to Qpid which is an integral control value. Further, if the result of the above comparison is | Qpid | ≧ Dx, the output from the adding unit 150 to the PWM signal output unit 152 is set to Dx which is a speed fluctuation threshold value. Note that | Qpid | is the absolute value of Qpid.

  When the final output correction unit 151 is not realized, the PWM signal output unit 152 receives the control value Qpid output from the addition unit 150. Conversely, when the final output correction unit 151 is realized, the control value that has passed through the final output correction unit 151 is input. The PWM signal output unit 152 outputs a PWM signal having a duty value obtained by converting the supplied control value. The timer 153 receives a signal from a clock (not shown). When a predetermined PID calculation period such as 100 μsec arrives, a timer signal is output to the speed calculation unit 142 for each PID calculation period.

  The motor driver 106 controls and drives the roll motor 33 or the PF motor 53 by PWM control based on the PWM signal output from the PWM signal output unit 152.

Next, the output correction unit 121 will be described. As described above, the output correction unit 121 executes calculation for obtaining the speed fluctuation threshold Dx described below, in addition to being realized as the integration correction unit 149 and the final output correction unit 151. As shown in (Equation 4), the calculation of the speed fluctuation threshold Dx is basically a Duty value that is a duty value necessary to give a prescribed tension F that gives a tension that prevents the paper P from being torn. f) and addition of Duty (ro), which is a duty value required to drive the roll motor 33 at a certain speed Vn.
Dx = Duty (f) + Duty (ro) = F * r * Duty (max) / (Kt * E) + aVn + b (Formula 4)
Here, r is the radius of the roll body RP, Duty (max) is the maximum value of the Duty value, Kt is the motor constant of the roll motor 33, E is the power supply voltage value supplied to the roll motor 33, and the coefficients a and b are It is a value defined by the following (formula 6) and (formula 7). The above (formula 4) is obtained as follows.

<Calculation method of (Formula 4)>
In order to determine the duty value required to drive the roll motor 33 at a certain speed Vn, the measurement operation (measured the output value of the motor when the motor is rotated at a predetermined rotational speed in order to know the motor load) ) Is running. In this measurement operation, as shown in FIG. 9, the roll body RP is driven to rotate at a low speed VL and a high speed VH. Then, a measurement value ave TiL required to drive the roll motor 33 at the low speed VL and a measurement value ave TiH required to drive the roll motor 33 at the high speed VH are calculated. Note that the measurement value ave TiL and the measurement value ave TiH are averages of control values output from the integration element 127 when PID control is performed at each speed.

From the relationship of the linear expression as shown in FIG. 9, the duty (ro) for driving the roll motor 33 at a certain speed Vn can be easily obtained using the coefficients a and b.
Duty (ro) = aVn + b (Formula 5)
a = (ave TiH−ave TiL) / (VH−VL) (Formula 6)
b = ave TiH− (ave TiH−ave TiL) × VL / (VH−VL) (Expression 7)

Also, consider a case where the roll motor 33 is driven at a certain speed Vn and tension F is applied to the paper P at that time. At that time, the current value Io required to drive the roll motor 33 is as follows, assuming that the radius of the roll body RP is r, the torque required to drive the roll motor 33 is Tro, and the motor constant is Kt. It is calculated by the following formula.
Io = (F × r + Tro) / Kt (Equation 8)

Here, the duty value Dx (speed fluctuation threshold) required when the roll motor 33 is driven while applying the tension F at a certain speed Vn is the power supply voltage E, the internal resistance R of the roll motor 33, and the back electromotive force of the roll motor 33. Assuming that the power constant is Ke, the following is obtained.
Io = (E * Dx / Duty (max) -KeVn) / R (Formula 9)

Further, assuming that the torque Tro required to drive the roll motor 33 at a certain speed Vn and the duty value at that time is Duty (ro), the torque Tro is obtained from the product of the current value I1 and the motor constant.
Tro = Kt × I1 = Kt × (E × Duty (ro) / Duty (max) −Ke × Vn)
... (Formula 10)

(Equation 8) and (Equation 9) are the same. Further, when (Equation 10) is substituted into Tro of (Equation 8) and both sides are arranged, the following is obtained.
(F × r / Kt) + (E × Duty (ro) / Duty (max) −Ke × Vn) / R
= (E * Dx / Duty (max) -Ke * Vn) / R
∴Dx = F × r × Duty (max) / (Kt × E) + Duty (ro) (Equation 11)
Duty (f) = F × r × Duty (max) / (Kt × E) (Equation 12)

  From (Equation 11) and (Equation 5), the duty value Dx corresponding to the speed fluctuation threshold is eventually expressed as the following equation.

  Dx = F * r * Duty (max) / (Kt * E) + aVn + b (Formula 4)

<Verification of measurement value>
As described above, the measurement values ave TiL and ave TiH necessary for driving the roll motor 33 at the speed VL and the speed VH were obtained using (Expression 6) and (Expression 7). The measurement value is an average value of the control values output from the integration element 127 as described above.

  However, the measurement value ave TiL for obtaining the speed VL and the measurement value ave TiH for obtaining the speed VH may be obtained inaccurately for some reason. If the above-described coefficients a and b are obtained based on such an inaccurate measurement value, it becomes impossible to obtain an accurate duty using the above-described (Equation 5), causing a problem in motor control. .

  Therefore, here, it is possible to verify whether or not the obtained measurement values ave TiL and ave TiH are abnormal values by the following method.

The measurement value ave TiL required to drive the roll motor 33 at the low speed VL and the measurement value ave TiH required to drive the roll motor 33 at the high speed VH by the above-described method. Is obtained, it is determined whether or not the obtained measurement value satisfies the following inequality.
Amin <ave TiH <Amax
Bmin <ave TiL <Bmax

  If the above inequality is not satisfied, the acquired measurement value is regarded as an abnormal value, and the above-described coefficients a and b are not calculated using such a measurement value. In such a case, the measurement values ave TiH and ave TiL are obtained again. On the other hand, when the upper inequality is satisfied, the coefficients a and b are obtained using the acquired measurement values ave TiH and ave TiL.

  By the way, Amin, Amax, Bmin, and Bmax that define the range of each measurement value in the above inequality can be obtained as follows.

  In this embodiment, Amin that defines the range of the measurement value is the measurement value when the roll motor 33 is driven at the low speed VL when the roll paper has the minimum weight. As Amax for defining the measurement value range, the measurement value when the roll motor 33 is driven at the low speed VL when the roll paper has the maximum weight is employed. Note that the weight of the roll body in the present embodiment is a minimum of 0.5 kg and a maximum of 15 kg.

  For example, Amin may be obtained by actually measuring the measurement value at that time by driving the roll motor 33 at the speed VL when the roll paper at the minimum weight is set. Similarly, Amax can be obtained by actually measuring the measurement value at that time by driving the roll motor 33 at the speed VH when the roll paper at the maximum weight is set. The values Amin and Amax obtained in this way may be slightly different depending on individual differences of individual motors. Therefore, the values obtained when a plurality of motors are used as the roll motor 33. An average value can also be adopted.

  Alternatively, Amin and Amax may be obtained by estimation. For example, when the roll body is rotated at a constant speed, the torque necessary for the roll motor 33 to maintain the constant speed rotation supports the roll body and transmits a driving force (torque) from the roll motor 33 to the roll body. Torque corresponding to the friction loss consumed by the transmission mechanism. Therefore, the total friction coefficient of the transmission mechanism is obtained in the design stage in advance, and the torque for the friction loss when the roll body is 0.5 kg, the torque for the friction loss when the roll body is 15 kg, and the like. Based on this, it is possible to estimate the range of measurement values Amin to Amax that can be taken.

  Similarly, the measurement value at the time when the roll motor 33 is driven at the high speed VH when the roll paper has the minimum weight is adopted as Bmin for defining the measurement value range. As Bmax that defines the range of the measurement value, the measurement value when the roll motor 33 is driven at the high speed VH when the roll paper has the maximum weight is employed.

The measurement value can be verified based on whether or not the difference between the measurement values aveTiH and aveTiL is within a predetermined range. At this time, it is determined whether or not the following inequality is satisfied.
SAmin <ave TiH-ave TiL <SAmax

If the above inequality is not satisfied, the acquired measurement value is regarded as an abnormal value, and the above-described coefficients a and b are not calculated using such a measurement value. In such a case, the measurement values ave TiH and ave TiL are obtained again. On the other hand, when the upper inequality is satisfied, the coefficients a and b are obtained using the acquired measurement values ave TiH and ave TiL.
The values of SAmin and SAmax are
SAmin = Amin + Bmin
SAmax = Amax + Bmax
You can ask for it.

  In this way, it can be determined whether or not the measurement value is an abnormal value. Then, it is possible to prevent the coefficients a and b from being obtained using the measurement value when the value is an abnormal value.

  The measurement operation and the verification of the measurement value as described above are naturally applicable to motors other than the roll motor 33. For example, the present invention can also be applied to the PF motor 53.

<Control Method for Roll Motor 33 and PF Motor 53>
A method of synchro drive control (skew removal) of the roll motor 33 and the PF motor in the printer 10 having the above configuration will be described below with reference to the processing flow of FIG.

  First, prior to driving for carrying out skew removal, a measurement operation is executed (S01). In the measurement operation, the roll motor 33 is driven at two speeds VL and VH on the low speed side and the high speed side on the basis of a command from the main control unit 110, and thereby the coefficient a in the above-described (Equation 4) , B are obtained.

Subsequently, the feed amount by driving the roll motor 33 is calculated (S02). The calculation of the feed amount is based on the pulse number count in the rotary sensors 34b and 54b. The feed amount Lroll (the count number of the ENC signal) is counted when the transport driving roller 51a makes one round. The count number of the ENC signal is Cpf, the count number of the ENC signal counted when the roll body RP makes one round is Croll, the diameter of the transport drive roller is Dpf, the diameter of the roll body RP is Droll, and the feed amount of the transport drive roller If the count number of the ENC signal corresponding to is Lpf, it is obtained by the following equation.
Lroll = (Dpf × π × Lpf / Cpf) / (Droll × π) × Croll (Formula 13)

  Here, since the diameter Droll of the roll body RP changes as the paper P is pulled out, it is necessary to obtain the diameter Droll. As a method for calculating the diameter Droll, only one of the roll motor 33 and the PF motor 53 is energized, and the other is not energized, and the ENC signal output from the rotary sensors 34b and 54b is counted. Some are calculated based on the number relationship. Further, from the relationship between the detected value from the direct detection (not shown) existing between the roll body RP and the conveying roller pair 51 and the count number of the ENC signal output from one of the rotary sensors 34b and 54b. The diameter Droll may be calculated.

  When the feed amount is calculated in S02, driving of the roll motor 33 and the PF motor 53 is started based on a command from the main control unit 110 (S03). At this time, the roll motor 33 and the PF motor 53 are driven according to a drive table as shown in FIG. In the drive table shown in FIG. 8, the feeding speed of the paper P driven by the roll motor 33 is set to be larger than the feeding speed driven by the PF motor 53 to prevent the paper P from slackening. . Note that “sagging” refers to a case where there is a portion where no tension in the transport direction is generated in any portion of the sheet between the roll body RP and the transport roller pair 51. In other words, “sag” means that the sheet P is maintained in a straight line state and is not curved when the roll body RP and the transport roller pair 51 are viewed from the side as shown in FIG. That means.

  Further, when the roll motor 33 and the PF motor 53 are driven, if the paper P is loosened between the roll body RP and the transport roller pair 51, the skew generated in the paper P cannot be eliminated. Therefore, whether the roll motor 33 and the PF motor 53 are driven simultaneously, or the roll motor 33 is driven first, and then the PF motor 53 is driven when the roll motor 33 is rotationally driven by a predetermined amount. Either driving method is employed.

  Further, when the roll motor 33 and the PF motor 53 are driven in S03, the roll motor 33 and the PF motor 53 are driven while controlling the tension F acting on the paper P. In the control of the tension F, as described above, either the integral correction unit 149 or the final output correction unit 151 compares the magnitude relationship with the speed fluctuation threshold Dx. That is, when using the integral correction unit 149, the absolute value of the integral control value QI output from the integral element 147 is compared with the speed fluctuation threshold value Dx. If the comparison result is | QI | <Dx, the integral correction is performed. The output from the unit 149 to the adding unit 150 is set as QI which is an integral control value. If the result of the above comparison is | QI | ≧ Dx, the output from the integral correction unit 149 to the addition unit 150 is set to Dx which is a speed fluctuation threshold value.

  When the final output correcting unit 151 is used, the control value Qpid output from the adding unit 150 is compared with the speed fluctuation threshold value Dx. If the result of this comparison is | Qpid | <Dx, the adding unit 150 The output to the PWM signal output unit 152 is Qpid which is an integral control value. Further, if the result of the above comparison is | Qpid | ≧ Dx, the output from the adding unit 150 to the PWM signal output unit 152 is set to Dx which is a speed fluctuation threshold value. In S02, the tension control for preventing the paper P from being damaged as described above (control to prevent the integrated output or the final output from exceeding the speed fluctuation threshold value Dx) is performed in S02.

  When the driving while controlling the tension in S03 as described above proceeds, the paper P is wound around the roll body RP in a state where the tension F is applied. Here, when the paper P is skewed, as shown in FIG. 11, when the paper P proceeds from one end side to the other end side in the width direction of the paper P (main scanning direction in which the carriage 41 scans), one end side However, there is no slack, but the slack amount of the paper P gradually increases toward the other end. Therefore, when the paper P is wound around the roll body RP while applying tension as in S03, in the slack portion of the paper P, at the stage where the slack portion is not wound, it is further downstream. The sheet P existing at the side portion is not sent toward the upstream side. Therefore, if the paper P is wound around the roll body RP while applying tension, the skew generated in the paper P can be eliminated.

  During the process of S03 as described above, the main control unit 110 determines whether or not a predetermined feed amount has been sent at every predetermined timing (S04). The feed amount here is the feed amount Lpf and the feed amount Lroll in S01 described above. The determination in S04 may be made based on only one of the feed amount Lpf and the feed amount Lroll.

  In S04 described above, when it is determined that a predetermined feed amount has been sent (in the case of Yes), the driving of the roll motor 33 and the PF motor 53 is stopped (S05). At this time, according to the drive table shown in FIG. 8, the PF motor 53 is stopped first, and then the roll motor 33 is stopped. However, the PF motor 53 and the roll motor 33 may be stopped simultaneously.

  If it is determined in S04 that the predetermined amount of feed is not sent (No), the process returns to S03 and the process is continued.

<Effects of application of this embodiment>
According to the printer 10 configured as described above, the tension applied to the paper P is controlled to be equal to or less than the tension F. Accordingly, it is possible to prevent a large tension from acting on the paper P, and it is possible to prevent problems such as the paper P breaking. In particular, as shown in FIG. 11, when the paper P is skewed, the amount of slackness of the paper P gradually increases from the one end side to the other end side of the paper P. For this reason, it is possible to satisfactorily prevent the paper P from being broken when the tension is applied to only one end side of the paper P where no slack occurs.

  In addition, the skew generated in the paper P can be satisfactorily eliminated by winding the paper P around the roll body RP while controlling the tension.

  Furthermore, as shown in FIG. 7, when the integral correction unit 149 is provided, the control value output from the integral element 147 passes through the integral correction unit 147, thereby providing a speed fluctuation threshold value Dx that gives a predetermined tension F. Is output to the addition unit 150 side, and the final output value in the PID control is calculated thereafter. By providing such an integral correction unit 149, it is possible to prevent a large tension from acting on the paper P, and it is possible to prevent the paper P from breaking.

  Further, as shown in FIG. 7, when the final output correction unit 151 is provided, the total value of the control values from the proportional element 146, the integral element 147, and the differential element 148 is obtained through the final output correction unit 151. The control value is output to the PWM signal output unit 152 in a state where the speed fluctuation threshold value Dx that gives the predetermined tension F is not exceeded. Therefore, it is possible to prevent a large tension from acting on the paper P, and it is possible to prevent the paper P from breaking.

  Furthermore, as shown in FIG. 8, the control unit 100 drives the roll motor 33 before the PF motor 53, or drives both at the same time. Therefore, it is possible to satisfactorily prevent the paper P from becoming slack when the PF motor 53 is driven.

  In this embodiment, the drive of the roll motor 33 and the PF motor 53 is controlled in a state where the feed amount of the paper P by the roll motor 33 is larger than the feed amount of the paper P by the PF motor 53. Therefore, the tension caused by the difference in the amount of feed between them is applied to the paper P, and the skew generated in the paper P when the paper P is taken up can be satisfactorily eliminated.

<Modification>
Although one embodiment has been described above, the present embodiment can be variously modified. This will be described below. In the above-described embodiment, the case where the motor control device is provided in the printer 10 has been described. However, the motor control device is not limited to being provided in the printer 10, and may be applied to a fax machine using a roll body (roll paper). In the embodiment described above, the paper P is a roll paper, but other than the paper P, a film-like member, a resin sheet, an aluminum foil, or the like may be used.

  In the above-described embodiment, when detecting a level change of the output signal (ENC signal), two ENC signals of A phase and B phase are used. However, when detecting a level change of the output signal, only one ENC signal or three or more ENC signals having different phases may be used.

  The control unit 100 is not limited to the above-described embodiment, and may be configured to control the roll motor 33 and the PF motor 53 using only the ASIC 105, for example. The control unit 100 may be configured by combining a one-chip microcomputer or the like in which a device is incorporated.

  Furthermore, in the above-described embodiment, the PID control in the control unit 100 is performed with respect to the speed, but PID control regarding the position may be performed. Further, the control of the roll motor 33 and the PF motor 53 is not limited to PID control, and the present embodiment may be applied to PI control. Further, when the integral correction unit 149 is not provided, the present embodiment may be applied to PD control, P control, and the like.

  The printer 10 in the above-described embodiment may be a part of a complex device such as a scanner device or a copy device. Furthermore, in the above-described embodiment, the ink jet printer 10 has been described. However, the printer 10 is not limited to an ink jet printer as long as it can eject fluid. For example, the present embodiment can be applied to various printers such as a gel jet printer, a toner printer, and a dot impact printer.

1 is a perspective view illustrating a configuration of a printer according to an embodiment. It is a figure which shows schematic structure of the printer of FIG. It is a perspective view which shows the structure of the rotation holder holding a roll body. It is a figure which shows an ENC signal. It is a figure which shows the positional relationship of a roll body, a conveyance roller pair, and a print head. It is a block diagram which shows an example of a structure of a control part. It is a block diagram which shows schematic structure of a PID calculating part. It is a figure which shows an example of a speed table. It is a figure which shows the relationship between the Duty value and speed | velocity | rate in measurement operation | movement. It is a figure which shows the operation | movement flow in synchro drive control. FIG. 6 is a perspective view illustrating a state where a skew is generated in a sheet.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Printer, 20 ... Main-body part, 30 ... Roll drive mechanism,
33 ... Roll motor (corresponding to the first motor, 34, 54 ... rotation detector,
34b, 54b ... linear sensor, 40 ... carriage drive mechanism,
44... Print head (corresponding to fluid ejecting head), 50... Paper transport mechanism,
51 ... pair of conveyance rollers, 53 ... PF motor (corresponding to the second motor),
100 ... control unit,
110 ... Main control unit, 120 ... Roll motor control unit, 121 ... Output correction unit,
130 ... PF motor control unit, 140a, 140b ... PID calculation unit,
149 ... Integral correction unit, 151 ... Final output correction unit, RP ... Roll body,
P ... paper (supports roll paper)

Claims (12)

A first motor for providing a driving force for rotating a roll body around which a medium is wound;
A second motor for supplying a driving force for driving a transport driving roller for transporting the medium, which is a transport driving roller provided on the downstream side of the roll body along the supply direction of the medium;
When the medium is transported by driving both the first motor and the second motor, the first tension is applied to the medium between the roll body and the transport driving roller so as to be not more than a predetermined value. A control unit for controlling the motor;
A printing apparatus comprising:   The control unit controls the first motor and the second motor so that the medium is conveyed in a direction opposite to the supply direction in order to wind the medium around the roll body. The printing apparatus as described.   The control unit compares a control value output from an integration element in PID control with a speed fluctuation threshold that varies according to the conveyance speed of the medium and gives a predetermined tension, and performs the control The printing apparatus according to claim 2, wherein when the value exceeds the speed fluctuation threshold, correction is performed to change the control value to the speed fluctuation threshold.   The control unit is a speed fluctuation threshold that varies according to a total value of control values output from a proportional element, an integral element, and a differential element in PID control, and a speed at which the predetermined tension is applied according to the conveyance speed of the medium. The printing apparatus according to claim 2, wherein a correction is performed by comparing with a fluctuation threshold, and when the total value exceeds the speed fluctuation threshold, the total value is changed to the speed fluctuation threshold.   5. The control unit according to claim 2, wherein the controller starts driving the first motor and the second motor simultaneously, or starts driving the first motor before driving the second motor. The printing apparatus in any one.   The control unit controls the first motor and the second motor such that a conveyance speed of the medium driven by the first motor is faster than a conveyance speed of the medium driven by the second motor. The printing apparatus according to claim 2.   The relationship between the control value for driving the first motor and the rotation speed of the first motor with respect to the control value is expressed by a linear expression, and the primary expression rotates the first motor at the first rotation speed. The printing apparatus according to claim 1, wherein the printing apparatus is obtained based on a first control value at the time and a second control value at the time of rotation at the second rotation speed.   The primary equation is rotated at the first control value when the first control value is a value within a first predetermined range when rotating at the first rotation speed, and at the second rotation speed. The printing apparatus according to claim 7, wherein the second control value is obtained based on the second control value when the second control value is a value within a second predetermined range. The first predetermined range is based on a control value for the first motor when rotating the roll body at the minimum weight at the first rotation speed and the roll body at the maximum weight. Sought after,
The second predetermined range is based on a control value for the first motor when rotating the roll body at the minimum weight at the second rotational speed and the roll body at the maximum weight. The printing apparatus according to claim 8, which is required.   The linear expression is obtained based on the first control value and the second control value when a difference between the second control value and the first control value is within a predetermined range. The printing apparatus according to 7 to 9. A first motor for providing a driving force for rotating a roll body around which a medium is wound;
A second motor for supplying a driving force for driving a transport driving roller for transporting the medium, which is a transport driving roller provided on the downstream side of the roll body along the supply direction of the medium;
When the first motor and the second motor are driven together to transport the medium, the control of the first motor is performed so that the tension generated between the roll body and the transport driving roller is less than a predetermined value. A control unit for performing
A fluid ejecting head that ejects fluid to the medium;
A printing apparatus comprising: A first motor for providing a driving force for rotating the roll body around which the medium is wound, and a drive for driving a conveyance driving roller provided on the downstream side in the medium supply direction for conveying the medium. Driving the second motor for applying force together to convey the medium;
Controlling the first motor so that the tension generated between the roll body and the transport drive roller is below a predetermined level;
Including printing method.

Images