JP3240815B2 - Tape tension control method and tape tension control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a tape drive mechanism using a two-reel motor for independently driving a reel on a supply side and a reel on a take-up side. The present invention relates to a tape tension control method and a tape tension control device for controlling a back tension of a tape wound on a tape.

[0002]

2. Description of the Related Art Conventionally, in a recording / reproducing apparatus using a tape-shaped recording medium such as a tape recorder or a video tape recorder, during recording / reproducing (hereinafter referred to as "playing"), the recording medium is fed by a capstan and a pinch roller. The tape is wound on the take-up reel without slack, and the tape is wound at high speed by rotating the take-up reel at high speed to take up the tape. Back tension, which is a tensile force in the opposite direction to that of the tape, is applied to the tape.

If the operation is switched from the stop state to the play state without the back tension during the play, the reel instantaneously rotates to feed the tape faster than the running speed of the tape by its inertia, and the tape sags. I do. After that, the reel gradually decreases its rotation, and when the rotation speed is lower than the tape sending speed, the reel intermittently rotates again and again as if the tape is suddenly pulled. This is hunting and causes irregular wows. For this reason, a back tension that is sufficiently smaller than the tape driving force of the capstan is required so that the tape does not sag during play and that the tape is sufficiently adhered to the head. This back tension is given by frictional resistance in the reel mechanism or a rotational force in a direction opposite to the tape feeding direction, and is expressed by a rotational torque (gram-cm, g-cm).

[0004] If the back tension is uneven, wow
This causes flutter and level fluctuations. In particular, in the case of a mechanism using a rotary head that performs helical scanning such that there is no pad and the head is in close contact only by the tension of the tape, the effect is further increased. On the other hand, if the back tension is too strong, the tape is strongly stretched between the tape and the capstan, causing a slip at the capstan or stretching the tape. If a slip occurs due to an increase in the back tension, the tape speed naturally decreases, and the wow and flutter increase.

[0005] The back tension is controlled by a mechanical method and an electric method. In a tape drive mechanism using a two-reel motor that independently drives the reel on the supply side and the reel on the take-up side, an electric motor that controls the back tension by applying the rotational force of the reel motor in a direction opposite to the direction in which the tape is fed out. Method is adopted. Actually, the motor drive voltage of the supply-side reel motor is increased or decreased according to the tension value detected by the tension sensor as the tension detecting means. That is, when the back tension is to be controlled by the supply-side reel motor, the supply-side reel motor is turned to the opposite side,
The generated torque was used. Hereinafter, the device for controlling the back tension by this electrical method will be described as a conventional back tension control device.

The back tension control of this conventional back tension control device is effective only when the tape traveling speed is low, and when the tape speed is high, the back electromotive force of the supply reel motor causes an influence. No matter how low the voltage, the tension cannot be reduced.

For this reason, it has been considered that when the tape speed becomes high, the supply-side reel motor is switched in the normal rotation direction and turned to control the back tension by the generated torque.

[0008]

In the conventional back tension control device, the back tension is controlled by rotating the supply-side reel motor in only one of the reverse direction and the normal direction. Is relatively easy because it is only necessary to increase or decrease the forward drive voltage. However, when the above-described switching is performed, the back tension cannot be controlled only by increasing or decreasing the drive voltage in the area near the switching point.

[0009] This is because in the area near the switching point, if the motor is reversed, the tension increases,
This is because if the rotation is normal, the tension becomes too small and the worst-case tape sags.

Hereinafter, the reason why the back tension cannot be controlled in the area near the switching point in the conventional back tension control device will be described with reference to FIGS. FIGS. 7 and 8 both show a state in which the back tension is controlled near the tape end EOT when the magnetic signal recording / reproducing apparatus using the rotary head is running the tape forward at 30 times speed. In this back tension control device, the drive voltage of the reel motor is controlled so that the output voltage of the tension sensor becomes constant at 1.6 V.

FIG. 7 shows a state in which the conventional back tension control device controls the back tension by rotating the supply side reel motor only in the reverse direction opposite to the tape running direction. FIG. 7A shows a change in the output voltage of the tension sensor. FIG. 7B shows a change in the drive voltage of the reel motor. In both cases, the horizontal axis indicates time.

The tension output voltage of the tape sent out from the supply reel of the magnetic signal recording / reproducing apparatus tends to be increased because the winding diameter of the supply reel decreases toward the tape end point EOT. Therefore, from the vicinity of the point P _a shown in FIG. 7 (B) at time t _1, the conventional back tension control device lowers the driving voltage of the supply-side reel motor, when you suppress tension output. However, tension output voltage shown in FIG. 7 (A) past the time t ₂ begins to rise from the vicinity of the point P _b. Therefore, this conventional back tension control device, the driving voltage of the supply-side reel motor, it is performed to further lower the point P _c at time t _2. However, the tension output voltage continues to rise as shown in FIG.

FIG. 8 shows a state in which the conventional back tension control device controls the back tension by rotating the supply-side reel motor only in the same forward direction as the tape running direction. FIG. 8A shows a change in the output voltage of the tension sensor. FIG. 8B shows a change in the drive voltage of the reel motor. In both cases, the horizontal axis indicates time.

[0014] The tape of the output voltage of the tension sensor is fed from the supply reel of the magnetic signal recording and reproducing apparatus reaches 1.6V is near time t _3. At time t ₃ the past, by forward the supply-side reel motor, gone slack tape, it does not increase the output voltage of the tension sensor. At time t ₃ , FIG.
Rapidly raising the tension output voltage as a point P _d shown in (A). Then, the back tension control device changes the drive voltage of the supply-side reel motor to the state shown in FIG.
Increase as the point P _e shown in.

Accordingly, at time t in FIG.
_In the region between _{1 and} t ₃ -t ₁ from time t ₃ in FIG. 8B, it is impossible to control the bakutension.

For this reason, when the tape speed changes from a low speed to a high speed, it is not possible to clarify a point at which the supply side reel motor is switched from the reverse rotation to the normal rotation, and it is not possible to perform tension control with high accuracy and resistance to disturbance.

In the vicinity of the switching point, the motor drive voltage is at a considerably low value, and in that state, even if the voltage is reduced, there is almost no effect and disturbance cannot be suppressed effectively.

Further, even if the switching is simply switched from inversion to normal rotation near the switching point, there is no point where the tension becomes flat before and after the switching.

The present invention has been made in view of the above circumstances, and realizes a highly accurate back tension control that is resistant to disturbances at any tape speed such as low speed or high speed, and provides a good head output. A control method and an apparatus are provided.

[0020]

A tape tension control method according to the present invention is used in a tape drive mechanism using a two-reel motor for independently driving a reel on a supply side and a reel on a take-up side. In a tape tension control method for controlling a back tension of a tape sent out from a reel and wound on a take-up reel, a tape tension detecting step of detecting a tension of the tape, and a tape tension detection detected in the tape tension detecting step Signal and reference
A position error detection signal for detecting a position error detection signal at the time of tape running from a difference from the tape position signal, an integration processing step of performing integration processing on the position error detection signal detected in the position error detection step, and the tape Detected in the tension detection process
Differential processing step of performing differential processing on the detected tape tension detection signal
And the differential processing output from the differential processing step and the position
An adding step of adding at least the error detection signal;
The supply reel motor feeds the tape from the supply reel.
Detects the tape tension when it is reversed with respect to the rotation direction.
When the tape tension detection signal detected in the process is
And the addition output of the addition step is the supply side
Smaller than the lower limit value of the stabilization drive voltage of the reel motor.
In addition, the output signal of the integration processing step is
The above supply reel motor rotates forward when
When the supply reel motor is rotating forward.
The tape tension detection signal detected in the tape tension detection process
Smaller than a predetermined reference value and
The force is the lower limit of the stabilized drive voltage of the supply reel motor.
Smaller, and the output signal of the integration processing step is
When the voltage is smaller than the lower limit of the stabilized drive voltage,
Of the supply side reel motor so that the
Control process for switching the direction of rotation.
Solve the problem.

The tape tension control device according to the present invention is used in a tape drive mechanism using a two-reel motor that independently drives the supply-side and take-up-side reels. In a tape tension control device for controlling a back tension of a tape wound on a side reel, a tape tension detecting means for detecting a tension of the tape, a tape tension detection signal detected by the tape tension detecting means, and a reference tape position signal When
Position error detection means for detecting a position error detection signal at the time of tape running from the difference between the two, an integration processing means for integrating the position error detection signal detected by the position error detection means, and a detection by the tape tension detection means Tape tension
A differential processing means for differentiating the detection signal;
Differential processing output from the processing means and the position error detection signal
Adding means for adding at least
Data in the direction of tape feed rotation of the supply side reel.
Is detected by the above-mentioned tape tension detection means when
The tape tension detection signal is larger than the specified reference value.
The addition output of the addition means is
Smaller than the lower limit value of the stabilized drive voltage, and
Output signal of the control means is smaller than the lower limit value of the stabilized drive voltage.
In this case, rotate the supply reel motor forward to
Tape tension detection when the side reel motor is rotating forward
The tape tension detection signal detected by the
And the addition output of the addition means is on the supply side.
Smaller than the lower limit value of the stabilization drive voltage of the reel motor.
Further, the output signal of the integration processing means is equal to the stabilized drive voltage.
The above-mentioned supply reel motor is reversed when it is smaller than the lower limit of
Cut the rotation direction of the supply-side reel motor
To solve the above problem by having
You.

[0022]

In the control step of the tape tension control method according to the present invention, the supply-side reel motor is controlled by the supply-side reel motor.
When the tape is reversed with respect to the
The tape tension detection signal detected in the
Addition output of the above addition process that is larger than the fixed reference value
Is lower than the lower limit of the stabilized drive voltage of the supply reel motor.
And the output signal of the integration processing step is
Supply reel when the lower than the lower limit value of the stabilized drive voltage
The motor rotates forward, and the supply side reel motor rotates forward.
The tape tension detected in the tape tension detection process
If the force detection signal is smaller than the predetermined reference value and
The added output of the process is the stabilization drive of the supply side reel motor.
It is smaller than the lower limit of the voltage and
When the force signal is smaller than the lower limit of the stabilized drive voltage
Reverse the supply reel motor so that the supply reel motor reverses.
Switch the rotation direction of the ruler motor.

The control means of the tape tension control device according to the present invention is characterized in that the supply-side reel motor includes a supply-side reel motor.
Up when it is reversed with respect to the
Tape tension detection signal detected by the tape tension detection means
Is larger than a predetermined reference value, and
Output is the lower limit of the stabilized drive voltage of the supply reel motor.
Value and the output signal of the integration processing means
If the supply voltage is smaller than the lower limit of the
Of the supply reel motor.
The tape detected by the tape tension detection means
The tension detection signal is smaller than the predetermined reference value and
The addition output of the addition means stabilizes the supply reel motor.
Smaller than the lower limit value of the drive voltage, and
Is smaller than the lower limit of the stabilized drive voltage.
The supply reel motor to reverse the supply
Switches the rotation direction of the side reel motor.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment to which a tape tension control method and a tape tension control device according to the present invention can be applied will be described below with reference to the drawings.

This embodiment is, as shown in FIG. 1, a back tension control device for controlling the back tension of the magnetic tape 3 sent out from the supply reel 1 and wound on the take-up reel 2.

The magnetic tape 3 is wound around the rotating drum 4 at an angle and is pressed against the rotating capstan 6 by the pinch roller 5 and travels in the forward direction F at a predetermined speed.
It is taken up by the take-up reel 2.

The take-up reel 2 is rotated by a driving force of a take-up reel motor (not shown). When the magnetic tape is run in the reverse direction R, the supply-side reel 1 is rotated by the driving force of the supply-side reel motor 7 in the direction of the arrow a in the figure. That is, the tape tension control device is used in a tape drive mechanism using a two-reel motor that independently drives the supply-side and take-up-side reels.

This back tension control device uses a tape
A tape tension detector 8 as tension detecting means is provided.
I have. One end 8a of the tape tension detector 8 is fixed.
And a tension spring provided with a detection pin 8c at the other end.
8b. Magnetic tape runs in forward direction F
In other words, when the magnetic tape 3 is
When the magnetic tape 3 is wound around the
If the position is large, the detection pin 8c moves in the direction indicated by the arrow Y in FIG.
That is, it moves in the direction in which the extension spring 8b is extended. Ma
If the tension of the magnetic tape 3 is small, the detection pin 8c
Is moved by the tension spring 8b in the direction of arrow X in the figure.
I do.

As described above, the tape tension detector 8
The tape tension in the vicinity of the supply reel 1 is transferred to the detection pin 8c.
It can be detected based on information about movement. This detection
Information on the movement of the pin 8c is provided by the pin of the tension detector.
This is the position information of the
Signal (position signal of the detection pin of the tension detector)
The signal is supplied to the signal processing unit 10 via the amplifier 9.

The signal processing section 10 has a circuit configuration as shown in FIG. That is, the signal processing unit 10 detects the signal by the tension detector 8 and outputs the signal to the amplifier 9 and the input terminal 2.
1 the position of the detection pin of the tension detector supplied via
The difference between the position signal and the reference tape position signal
Position error detection circuit 22 for detecting as a color error detection signal
And the reference tape position signal to the position error detection circuit 22.
Obtaining a reference tape position signal generator generating circuit 23, an integration processing circuit 24 that the integration process is performed on the position error detection signal detected by the position error detection circuit 22, the tension detector
Processing circuit 2 for differentiating the position signal of the detection pin
7, an adder 28 described later, and a control circuit 30 for controlling the rotation direction of the supply-side reel motor 7 and the magnitude of the drive voltage.
And

The position error detection circuit 22 calculates a difference between the position signal of the detection pin of the tension detector detected by the tension detector 8 and the reference tape position signal from the reference tape position signal generation circuit 23. Multiplied by an appropriate constant to output a position error detection signal.

The integration processing circuit 24 outputs the position error detection signal output from the position error detection circuit 22 to the switch 2
5 is closed and subjected to integration processing. By the integration processing of the integration processing circuit 24 , the DC component of the position error detection signal is obtained.
Correction is performed. That is, integration calculation is performed by taking the sum of the position error detection signals, and the center voltage of the output voltage corresponding to the position error detection signal is corrected.

Here, a switch 25 inserted between the integration processing circuit 24 and the position error detection circuit 22 prevents the position error detection signal of the position error detection circuit 22 from being subjected to integration processing for a predetermined time. Control circuit 3 described later
Switching to 0 is controlled.

The differential processing circuit 27 includes the tension detector 8
Differentiation processing is performed on the position signal of the detection pin of the tension detector detected in step (1) . More specifically, the difference between the value sampled one time ago and the current sampled value is obtained, the kinetic energy of the tension detector 8 is suppressed, and the tension spring 8
It works to suppress the vibration of b. That is, it functions to compensate for the integral element of the extension spring 8b.

The adder 28 separates the position detection error signal from the position error detection circuit 22, the integration processing signal from the integration processing circuit 24, and the differentiation processing signal from the differentiation processing circuit 27 into two cases as described later. And add.

The control circuit 30 includes a position error detection circuit 22
And the processing output of the integration processing circuit 24, the detection output of the position error detection circuit 22, the processing output of the differentiation processing circuit 27, and the addition output of the processing output of the integration processing circuit 24. The rotation direction of the side reel motor 7 and the addition output are controlled.

That is, when the supply-side reel motor 7 is reversed with respect to the tape-feeding rotation direction F of the supply-side reel 1 (in the direction of arrow a in the figure),
The position error detection signal output by the position error detection circuit 22 is larger than a predetermined reference value, the output signal of the integration processing circuit 24 is smaller than the lower limit value of the stabilized drive voltage, and the output signal of the adder 28 is a predetermined value. If the rotation speed is smaller than the rotation speed, the rotation of the supply-side reel motor 7 is switched in the forward direction indicated by an arrow b in the drawing. When the supply-side reel motor 7 is rotating forward with respect to the tape-feeding rotation direction F of the supply-side reel 1 (in the direction of the arrow b in the drawing), the control circuit 30 controls the position error detection circuit 22 to operate. When the output position error detection signal is smaller than a predetermined reference value,
4 is smaller than the lower limit value of the stabilization drive voltage, and when the output signal of the adder 28 is smaller than a predetermined value, the rotation of the supply-side reel motor 7 is reversed in the reverse direction indicated by the arrow a in the figure. Switching.

When the control circuit 30 actually reverses or rotates the supply-side reel motor 7, the motor driver 1
5 and a control signal is supplied to the reel-on and reel-forward terminals.

The control circuit 30 includes a switch 29
, And the addition output from the adder 28, that is, P
The switching of the WM output signal is controlled. By opening and closing the switch 29, the PWM output signal is supplied to the LPF 11 or fed back to the differential processing circuit 27 and the position error detection circuit 22.

The PWM output signal supplied to the LPF 11 is band-limited by the LPF 11, amplified by the amplifier 12, and then supplied to the motor driver 15 via the switching transistor 13. The motor driver 15 includes:
The reel-on and reel-forward control signals are also supplied from the control circuit 30 of the signal processing unit 10, and the rotation direction and the drive timing of the supply-side reel motor 7 are determined.
For this reason, the supply-side reel motor 7 includes the motor driver 1
5, the rotation direction, drive timing and power are changed, and the supply-side reel 1 is rotated in the direction of the arrow a or b to apply back tension to the magnetic tape 3.

Here, the switch 25 does not supply the position error detection signal of the position error detection circuit 22 to the integration processing circuit 24 for a predetermined time as described above.
That is, the integration process is not performed. Immediately after the rotation of the supply-side reel motor 7 is switched by the control circuit 30, a position error has occurred, and the integration error increases in both cases of reversal to normal rotation or normal rotation to reversal. Further, the position error at this time is in an unstable state immediately after switching. As the integration error increases, the apparent DC potential rises, and in order for the output voltage to fall below a predetermined voltage, switching will not be performed unless the position error, which is an AC component, becomes large. That is, allowing the calculation of the integration error promotes oscillation. Therefore, immediately after the switching, for example, for 500 msec, the integration process is prohibited.

The overall operation of the back tension control device of this embodiment described above will be described with reference to FIGS. 1, 2 and 3. FIG. 3 is a flowchart showing the operation of the back tension control device.

The magnetic tape 3 sent out from the supply side reel 1 is wound around the rotating drum 4 at a slant, is pressed against the rotating capstan 6 by the pinch roller 5 and travels in the forward direction F at a predetermined speed. It is assumed that it is wound on the take-up reel 2.

First, as shown in step S1, the tape tension detector 8 detects the tension detector by moving a detection pin 8c provided at the other end of the tension spring 8b.
Detects the moving position of the output pin and detects the tension detector
A pin position signal is supplied to the amplifier 9.

Next, in step S2, it is determined whether or not the current rotation direction of the supply-side reel motor 7 is the reverse direction. If the result of this determination is that the supply-side reel is reversed, YES is selected and the process proceeds to step S3, and if it is normal rotation, NO is selected and the process proceeds to step S4.

Step S3 shows the operation of the position error detection circuit 22 in the signal processing unit 10. That is, the position error detection circuit 22, Teng tension detector 8 detects
The difference between the pin position signal of the position detector and the reference tape position signal from the reference tape position signal generation circuit 23 is obtained, and the difference is multiplied by an appropriate constant to output a position error detection signal.

Step S5 shows the operation of the differential processing circuit 27 in the signal processing section 10. That is, the differential processing circuit 2
7 is the tension detection detected by the tension detector 8
Differential processing is applied to the position signal of the pin of the container, and the difference between the value sampled one time ago and the currently sampled value is obtained.
It functions to suppress the kinetic energy of the tension detector 8 and to suppress the vibration of the tension spring 8b. That is, it functions to compensate for the integral element of the extension spring 8b.

Next, in step S6, before the execution of the integration process shown in step S7, it is determined whether or not the time period is suitable for performing the integration process. That is, immediately after the rotation direction of the supply-side reel motor 7 is switched, a position error occurs, and the integration error increases in both cases from inversion to normal rotation or from normal rotation to inversion. Further, the position error at this time is in an unstable state. Therefore, since the integration process immediately after the switching promotes oscillation, the control circuit 30 needs to inhibit the integration process immediately after the switching, for example, for 500 msec.
It is determined whether it is 00 msec. Where 5
If it is determined that the time is within 00 msec, YES is selected, the switch 25 is turned off, and the process proceeds to step S8 by skipping the integration process of step S7. If it is determined that it is not within 500 msec, NO is selected, the switch 25 is turned on, and the process proceeds to step S7.

Step S7 is performed in response to the result of selecting NO in step S6. That is, the integration processing circuit 24 receives the position error detection signal output from the position error detection circuit 22 when the switch 25 whose switching is controlled by the control circuit 30 is closed, and performs integration processing. The integration processing circuit 24 corrects the DC component of the position error detection signal. That is, the integral calculation is performed by taking the sum of the position error detection signals, and the center voltage of the output voltage corresponding to the position error detection signal is corrected.

Step S8 is an addition process performed after the integration process in step S7 or after YES is determined in the determination in step S6. When the processing is performed after the integration processing, the position detection error signal from the position error detection circuit 22, the integration processing signal from the integration processing circuit 24, and the differentiation processing signal from the differentiation processing circuit 27 are added by the adder 28. You. The result of the addition process becomes a PWM output signal and is supplied to the selection terminal a of the switch 29 and the control circuit 30. If the determination is made after YES is selected in step S6, only the position detection error signal from the position error detection circuit 22 and the differentiation processing signal from the differentiation processing circuit 27 are output for the reason described in step S6. The addition process is performed by the adder 28. The result of this addition is P
A WM output signal is supplied to the selection terminal a of the switch 29 and the control circuit 30.

The operations up to here, that is, the operations shown in steps S3 to S8 are the same as the operations from step S4 to step S12 performed after NO is selected in step S2. The description of the operation from S4 to step S12 is omitted.

The operations of steps S13, S14, and S15 described below are determinations made in the control circuit 30.

First, in step S13, it is determined whether or not the position error detection signal detected in step S3 is larger than a predetermined reference value. Here, when it is determined that the position error detection signal is larger than the predetermined reference value, YES is selected and the process proceeds to step S14. On the other hand, if it is determined that the position error detection signal is smaller than the predetermined reference value, NO is selected, and the rotation direction of the supply-side reel motor 7 is not switched, and the addition output obtained in step S8, that is, PWM is output.
Only the output signal is supplied to the LPF 11 as shown in step S21.
Supplied to

Next, in step S14, it is determined whether the added output detected in step S8, that is, the PWM output signal is smaller than a predetermined voltage value. Here, if it is determined that the addition output is smaller than the predetermined voltage value, YES
Is selected and the process proceeds to step S15. On the other hand, when it is determined that the addition output is larger than the predetermined voltage value, NO is selected, and
The rotation direction of the supply-side reel motor 7 is not switched, and only the addition output obtained in step S8, that is, the PWM output signal is supplied to the LPF 11 as shown in step S21.

The operation shown in step S15 is controlled in accordance with the result of the determination in step S6. That is, the operation of step S15 is performed immediately after switching.
It is not performed within 00 msec, but after 500 msec. After 500 msec immediately after switching, it is determined whether or not the integration error signal, which is the integration processing output detected in step S7, is smaller than a predetermined value. Here, if it is determined that the integration error signal is smaller than the predetermined value, YES is selected and the process proceeds to step S16. On the other hand, if it is determined that the integration error is larger than the predetermined value, NO
Is selected, and the added output obtained in step S8, that is, P
As shown in step S21, only the WM output signal is LPF
11 is supplied.

In step S16, in response to the selection of YES in step S15, the rotation direction of the supply-side reel motor 7 is switched from the current inversion to the normal rotation. The operation in step S16 is performed only when YES is selected in steps S13, S14, and S15, and is naturally performed within 500 msec immediately after the switching shown in step S6. Not something.

Next, in step S4 after it is determined in step S2 that the supply-side reel motor 7 is rotating forward,
Steps S17 and S18 following steps S9, S10, S11 and S12.
The operation of step S19 will be described below. These steps S17, S18 and S
The operation 19 is also a determination made in the control circuit 30.

First, in step S17, it is determined whether or not the position error detection signal detected in step S4 is smaller than a predetermined reference value. Here, if it is determined that the position error detection signal is smaller than the predetermined reference value, YES is selected and the process proceeds to step S18. On the other hand, if it is determined that the position error detection signal is greater than the predetermined reference value, NO is selected, and the rotation direction of the supply-side reel motor 7 is not switched, and the addition output obtained in step S12, that is, PW
Only the M output signal is supplied to the LPF1 as shown in step S21.
1 is supplied.

Next, at step S18, it is determined whether the added output detected at step S12, that is, the PWM output signal is smaller than a predetermined voltage value. here,
When it is determined that the addition output is smaller than the predetermined voltage value, YE
S is selected and the process proceeds to step S19. On the other hand, if it is determined that the addition output is larger than the predetermined voltage value, NO is selected, and the rotation direction of the supply-side reel motor 7 is not switched, and only the addition output obtained in step S12, that is, the PWM output signal is changed to step S21. Is supplied to the LPF 11 as shown in FIG.

[0060] The operation shown in step S19 is executed according to the determination result at Step S1 0 is controlled. That is, the operation of step S19 is performed immediately after switching.
It is not performed within 00 msec, but after 500 msec. After 500 msec immediately after switching, it is determined whether or not the integration error signal, which is the integration processing output detected in step S11, is smaller than a predetermined value. Here, if it is determined that the integration error signal is smaller than the predetermined value, YES is selected and the process proceeds to step S20. On the other hand, if it is determined that the integration error is larger than the predetermined value, NO
Is selected, and the rotation direction of the supply-side reel motor 7 is not switched, and only the addition output obtained in step S12, that is, the PWM output signal is LP as shown in step S21.
It is supplied to F11.

In step S20, in response to the selection of YES in step S19, the rotation direction of the supply-side reel motor 7 is switched from the current normal rotation to the reverse rotation. The operation in step S20 is performed only when YES is selected in all of steps S17, S18, and S19, and is naturally performed within 500 msec immediately after switching shown in step S10. Not something.

The case where the back tension of the magnetic tape of the magnetic signal recording / reproducing apparatus which is actually running at 30 × speed is controlled by using the back tension control apparatus of this embodiment described above is shown in FIGS. This will be described with reference to FIG.

Initially, while the supply-side reel motor 7 is being subjected to reverse control, that is, a reverse control period CN _R
By controlling the back tension by gradually lowering the voltage for driving the supply-side reel motor 7, the tension output obtained via the tension detector 8 could be kept constant. However, by that past the time t ₁ approaching tape end EOT is, to come up the tape running speed, it becomes necessary to switch control the supply-side reel motor 7. FIG. 5 shows the control of the rotation direction and the drive voltage of the supply-side reel motor 7 performed by the control circuit 30 of the signal processing unit 10 of the back tension control device during the period CN _SW in which the switching control is performed. In this figure, F indicates a normal rotation control period, and R indicates a reverse control period. And FIG.
In further rises tape travel speed past the time t _2, the control circuit 30, by going up the driving voltage of the supply-side reel motor 7 causes forward rotation of the supply reel motor 7, a constant tension output can do. FIG this section as the forward control period CN _F.

The control circuit 30 of the signal processing unit 10
Then, the determinations in steps S13 to S15 and steps S17 to S19 shown in FIG. 3 are performed, and the predetermined voltages used in step S14 and step S18 among these determinations, and steps S15 to S19
What is the desired value of the predetermined value used in? This will be described below.

First, steps S14 and S18
The predetermined voltage used in will be described. The back tension control device of the present embodiment is made for the fact that the back tension cannot be controlled only by increasing or decreasing the drive voltage of the supply-side reel motor, and the rotation direction of the reel motor is reversed or corrected. The above-mentioned drive voltage was controlled mainly by switching such that the driving voltage was reversed. For this reason, the switching voltage at the time of performing the above-mentioned switching becomes important. When the switching voltage is too high, the difference in force at the time of switching is too large to cause an oscillation state, and when it is too low, a sufficient effect cannot be obtained. This switching voltage is determined in comparison with the predetermined voltage. The value of the predetermined voltage is preferably a lower limit value of the stabilizing drive voltage of the supply-side reel motor 7. For this reason, a stabilized drive voltage at which the forward rotation control and the reverse control generate almost the same force and the operation of the supply-side reel motor 7 is stabilized was obtained by a method as shown in FIG. That is, as shown in FIG.
Pass over an endless tape T _E between the take-up reel 42 and the motor of the take-up reel 42 in advance by rotating at a constant voltage, while varying the motor drive voltage (not shown) of the supply reel 41 The normal / reverse switching is performed via the driver 40, and the fluctuation of the rotation cycle due to the load of the supply-side reel 41 is checked to obtain the predetermined voltage value. Now, let this predetermined voltage value be _VRS . This predetermined voltage value V _RS is used in steps S14 and S18, and is compared with the addition output, that is, the magnitude of the PWM output signal. The predetermined voltage value is, for example, 1.
It is desirable that 1 <V _RS <1.3 (unit V). In particular, when the voltage was set to 1.2 V, the tension output was excellent in convergence and did not oscillate.

Next, step S15 and step S19
The predetermined value used in will be described. If only the magnitude of the PWM output signal is compared with the predetermined voltage value V _RS , the PWM output signal includes the position error detection signal and the differential processing signal, which are AC components, and thus lacks reliability. For this reason, it is necessary that the integration processing signal is also compared with the predetermined voltage value _VRS . In the back tension control device of the present embodiment, only the integration processing signal is to be compared.
In order to obtain a DC component with less variation, a biased integration processing signal may be used. It is desirable that the predetermined value also satisfies, for example, 1.1 <V _RS <1.3 (unit V). In particular, when the voltage was set to 1.2 V, the tension output was excellent in convergence and did not oscillate.

Further, the back tension control device of the present embodiment further adds to the above-mentioned determination whether or not the position error detection signal is larger than the reference value. This is because, for example, at the time of the inversion control, even if the added output voltage is smaller than the predetermined voltage value _VRS and the integration processing signal is smaller than the predetermined voltage value _VRS , but the position error detection signal is larger than the reference value, the reel motor is no longer used. Since the drive voltage of the reel motor 7 has no effect, the rotation direction of the reel motor 7 must be switched from reverse to normal to lower the tension. Then, during forward rotation control is similar, addition output voltage is less than the predetermined voltage V _RS,
Even if the integration processing signal is smaller than the predetermined voltage _VRS , if the position error detection signal is smaller than the reference value, the drive voltage of the reel motor 7 can be further reduced because there is no effect. It indicates that the tension must be increased by switching from to inversion.

It should be noted that the tape tension control method and the tape tension control device according to the present invention are not limited to the above-described embodiment, and that the tape tension detection signal is set to a predetermined reference value when the supply reel motor is reversed. The supply reel motor is rotated forward when the integration processing signal is larger than the lower limit value of the stabilization drive voltage, and the tape tension detection signal is output when the supply reel motor is rotating forward. Is smaller than a predetermined reference value, and the rotation direction of the supply-side reel motor may be switched so that the supply reel motor is reversed when the integration processing signal is smaller than the lower limit value of the stabilized drive voltage. .

[0069]

According to the tape tension control method of the present invention, in the control step, the supply side reel motor is controlled by the supply side reel motor.
Reversed with respect to the reel feeding direction
Sometimes, the tape tension detection
The output signal is greater than a predetermined reference value and
Is the stabilized drive voltage of the supply-side reel motor.
Is smaller than the lower limit value of
Signal is smaller than the lower limit of the stabilized drive voltage.
Rotate the supply reel motor forward and rotate the supply reel motor.
Is detected in the above tape tension detection process when
The tape tension detection signal is smaller than the specified reference value.
The addition output of the addition step is
Smaller than the lower limit value of the stabilized drive voltage, and
Output signal of the process is smaller than the lower limit of the stabilized drive voltage.
The supply reel motor above.
Since the rotation direction of the supply-side reel motor is switched, back tension control that is resistant to disturbance and highly accurate at any tape speed such as low speed or high speed can be realized, and a good head output can be obtained.

In the tape tension control device according to the present invention, the control means controls the supply side reel motor to
Reversed with respect to the reel feeding direction
Sometimes the tape tension detection means
The output signal is greater than a predetermined reference value and
Is the stabilized drive voltage of the supply-side reel motor.
Smaller than the lower limit value of
Signal is smaller than the lower limit of the stabilized drive voltage.
Rotate the supply reel motor forward and rotate the supply reel motor.
Is detected by the tape tension detecting means when
The tape tension detection signal is smaller than the specified reference value.
The addition output of the addition means is
Smaller than the lower limit value of the stabilized drive voltage, and
Output signal of the control means is smaller than the lower limit value of the stabilized drive voltage.
The supply reel motor above.
Since the rotation direction of the supply-side reel motor is switched, back tension control that is resistant to disturbance and highly accurate at any tape speed such as low speed or high speed can be realized, and a good head output can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a back tension control device according to an embodiment of the present invention.

FIG. 2 is a block circuit diagram of a signal processing unit of the back tension control device shown in FIG.

FIG. 3 is a flowchart for explaining the operation of the back tension control device shown in FIG. 1;

FIG. 4 shows a back tension control device shown in FIG.
FIG. 8 is a diagram used to explain a case where the back tension of the magnetic tape of the magnetic signal recording / reproducing apparatus that is performing double speed forward traveling is controlled.

FIG. 5 is an enlarged view of the switching control period shown in FIG. 4;

FIG. 6 is a diagram illustrating a method of obtaining a stabilized drive voltage of a supply-side reel motor.

FIG. 7 is a diagram for explaining control of a reverse direction of a conventional back tension control device.

FIG. 8 is a diagram for explaining control in a normal rotation direction of a conventional back tension control device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 supply reel 2 take-up reel 3 magnetic tape 4 rotating drum 8 tension detector 10 signal processing unit 11 low-pass filter 15 motor driver 22 position error detection circuit 23 reference tape position signal generation circuit 24 integration processing circuit 25 switch 27 differentiation processing Circuit 28 Adder 30 Control circuit

Claims (6)

(57) [Claims] 1. A tape drive mechanism using a two-reel motor for independently driving a reel on a supply side and a reel on a take-up side. In a tape tension control method for controlling a back tension, a tape tension detecting step of detecting a tension of the tape ; and A position error detection step of detecting a position error detection signal; an integration processing step of integrating the position error detection signal detected in the position error detection step; and a tape tension detection signal detected in the tape tension detection step.
A differential processing step for performing differential processing on the item, differential processing output and the position error from the differential processing step
An adding step of adding at least a detection signal, and the supply-side reel motor feeding the tape to the supply-side reel.
When the tape tension is reversed with respect to the
The tape tension detection signal detected in the detection process
Value and the addition output of the addition step is
It is smaller than the lower limit of the stabilized drive voltage of the supply reel motor.
In addition, the output signal of the integration processing step is
When the supply voltage is smaller than the lower limit of the dynamic voltage,
And the tape is rotated when the supply reel motor is rotating forward.
The tape tension detection signal detected in the tension detection process
It is smaller than the reference value and the addition output of the above addition process is
It is smaller than the lower limit of the stabilized drive voltage of the supply side reel motor.
In addition, the output signal of the integration process is stabilized.
When the drive voltage is lower than the lower limit,
Rotation of the supply-side reel motor so that the
And a control step of switching the direction.
Control method. 2. The method according to claim 1, wherein the control step includes:
Switch from reverse to normal or from normal to reverse
Within a predetermined time thereafter, the integration Prohibition
The tape tension according to claim 1, wherein
Control method. 3. The method according to claim 1, wherein the adding step includes controlling the control step.
From the reversing of the supply side reel motor to the forward rotation or
After a predetermined time immediately after switching from forward rotation to reverse
Is the sum of the differential processing output and the position error detection signal
Add the integration output of the above integration process to the output
The tape tension according to claim 1, wherein
Control method. 4. A tape drive mechanism using a two-reel motor for independently driving a reel on a supply side and a reel on a take-up side. In a tape tension control device for controlling back tension, a tape tension detecting means for detecting the tension of the tape, and a tape tension detecting signal detected by the tape tension detecting means and a difference between a reference tape position signal and a tape tension detecting signal during tape running. Position error detection means for detecting a position error detection signal; integration processing means for performing integration processing on the position error detection signal detected by the position error detection means; and tape tension detection signal detected by the tape tension detection means.
A differential processing means for performing a differential processing on the item, differential processing output and the position error from the differential processing unit
An adding means for adding at least the detection signal; and the supply-side reel motor for feeding the tape to the supply-side reel.
When the tape tension is reversed with respect to the
The tape tension detection signal detected by the detection means
Value and the addition output of the addition means is
It is smaller than the lower limit of the stabilized drive voltage of the supply reel motor.
And the output signal of the integration processing means is
When the supply voltage is smaller than the lower limit of the dynamic voltage,
And the tape is rotated when the supply reel motor is rotating forward.
The tape tension detection signal detected by the tension detection means
It is smaller than the reference value and the addition output of the addition means is higher
It is smaller than the lower limit of the stabilized drive voltage of the supply side reel motor.
Fence, and the output signal is the stabilization of the upper Symbol integrating unit
When the drive voltage is lower than the lower limit,
Rotation of the supply-side reel motor so that the
Control means for switching the direction.
Tension control device. 5. The control device according to claim 1, wherein the control unit controls the supply-side reel mode.
Switch from reverse to normal or from normal to reverse
Integral processing of the above-mentioned integral processing step is prohibited within a predetermined period of time
The tape tension according to claim 4, wherein
Control device. 6. The control device according to claim 1, wherein the adding means controls the control means.
From the reversing of the supply side reel motor to the forward rotation or
After a predetermined time immediately after switching from forward rotation to reverse
Is the sum of the differential processing output and the position error detection signal
In addition to the output, add the integration processing output of the integration processing means.
The tape tension according to claim 4, wherein
Control device.