JPS58208954A - Tape tension control system - Google Patents

Abstract

PURPOSE:To keep the tape tension to an optimum state at all times, by controlling the speed of a supply capstan with a tension control so that the tape tension is a preset optimum value. CONSTITUTION:The magnitude of a tension of a magnetic tape 6 being a tape recording medium between a tape supply capstan 31 and a tape rewinding capstan 32 is detected, and a tension control signal in response to the magnitude is obtained with a sensing sensor 1 and a sensing post 5. The rotating speed of the supply capstan 31 is controlled by applying the tension control signal to an electromagnetic brake 22 being a brake means provided to the tape supply capstan 31 so that the tension is the preset optimum tension.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tape tension control system, and uses a brake means provided on the supply side capstan to optimize the tape tension using a signal corresponding to the magnitude of the tape tension. It is an object of the present invention to provide a method that can control the rotation speed and maintain tape tension in an optimal state at all times.

Magnetic recording and reproducing devices that use magnetic tape as a recording medium include
Conventionally, a two-capstan type is sometimes used, which is effective in stabilizing tape tension, suppressing vibration components from the reel motor, and suppressing longitudinal vibration components of the tape. In this case, it is necessary to run the tape with an appropriate tension between the two capstans, but generally the circumferential speed of the capstan motor on the supply side is smaller than that of the capstan motor on the take-up side. drive the motor.

There are two types of devices of this type, one in which two capstans are driven by one drive motor, and the other in which each capstan is driven by two drive motors. Either use an elastic belt for the belt that wraps around the capstan, or use flywheels with different driving capacities for each capstan, or use an inelastic belt and use different diameters for each capstan or flywheel. The circumferential speed of each capstan motor is made different depending on the method used. For this reason, this product cannot maintain a predetermined capstan circumferential speed due to unevenness of the belt or elongation due to aging.
This method has drawbacks such as easy occurrence of wow and flutter.

On the other hand, in the latter case, there is no problem with the belt as in the method using a single drive motor, but due to the large mechanical impedance of the capstan, if the tape tension deviates from the set value due to some external cause, There was a drawback that it took a long time to return to the set value.

In addition, both methods have the disadvantage that it takes a long time from when the pinch roller is pressed to when the tape tension is stabilized.Furthermore, it is necessary to configure the tape tension to be set variably according to the thickness of the magnetic tape, food, etc. There were disadvantages such as difficulty in

The present invention eliminates the above-mentioned drawbacks, and an embodiment thereof will be described below with reference to the drawings.

1 and 2 respectively show a schematic plan view and a schematic circuit diagram of the main parts of a magnetic recording/reproducing apparatus to which an embodiment of the tape tension control method according to the present invention can be applied. The same number is given to the parts with . In the figure, 1 is a tension sensor, which includes a supply side pinch roller 21, a supply side capstan 31, and a supply side guide roller 4! It is fixed between. A sensing post 5 is supported on the upper surface of the tension sensor 1 so as to be movable in the directions of arrows a and b according to the tension of the magnetic tape 6.

The sensing post 5 is set so that when the Dave tension is at the optimum value, it is located at the center of the range that is off to the tension sensor 1.
If the tape tension becomes thicker than the optimum value against the elastic force of the spring installed inside, it is set to move toward the arrow a side, and when it is smaller than that, it moves toward the arrow b 911j. ing. The tension sensor 1 is configured to take out a voltage of a magnitude corresponding to the displacement of the sensing post 5 in the directions of arrows a and b with reference to the case where the tension is at an optimum value.

Reference numeral 22 denotes a magnetic brake, which has a U-shape and is attached to the outer peripheral side of the supply side flywheel 101 so as to face its upper and lower end surfaces. This device is operated by the output voltage from an amplifier 181, which will be described later, and the flywheel 10
It is configured to apply a brake to 1.

First, in the tape stop mode, the movable contacts of the switch 7, which coarsely move the supply side capstan 31 and the winding capstan 32 at a constant speed by phase control, are connected to the terminal (2). The supply-side capstan drive motor 81 is driven by an output from a drive circuit (not shown), and its rotation is transmitted via a belt 91 to the supply-side flywheel 10. A pulse proportional to the rotation speed of the motor 81 is extracted by opposing the pulse wheel 111 provided on the flywheel 101 and the F'G head 121.

This pulse is amplified by an amplifier 131 and then a discreet circuit 14. The voltage is converted into a voltage having a thickness corresponding to the frequency and is supplied to the servo amplifier 171, and is also supplied to the phase comparator 151.

On the other hand, the reference pulse from the oscillator 16 is transmitted to the phase comparator 151.
The phase is compared with the pulse from the amplifier 131 at the phase comparator 15. A phase comparison error voltage corresponding to the phase difference between both pulses is extracted and sent to the servo amplifier 1 via the switch 7.
71. In the servo amplifier 171, the discreet circuit 14. The voltage corresponding to the rotation speed of the motor 81 and the phase comparison error voltage from the phase comparator 151 are mixed and applied to the electromagnetic brake 22 via the drive amplifier 181. Here, from the electromagnetic brake 22, the amplifier 18
．． A braking force is generated according to the magnitude of the phase error voltage from the supply side flywheel 10. is braked, and as a result, the capstan 31 is phase-controlled by the phase error voltage from the drive amplifier 181 and rotates at a constant speed.

On the other hand, the winding side capstan 3! is different from the supply side capstan 31, and the motor 8. It is directly phase controlled and rotates at a constant speed. That is, the rotation of the take-up drive motor 82 is transmitted to the flywheel 10° via the belt 92, and the pulses obtained by the pulse wheel 112 and the FG head 122 are transmitted via the amplifier 132 to the discreet circuit 14.
2 and the phase comparator 152. Phase comparator 15
The output voltage from □ and the output voltage from the discretization circuit 142 are mixed by the servo amplifier 172 and then applied to the motor 82 via the drive amplifier 182, thereby controlling the phase of the capstan 32.

Here, when entering a tape running mode such as a recording mode, for example, the movable contact piece of the switch 7 is connected to the terminal @. In this case, a voltage corresponding to the position of the sensing post 5 is extracted from the tension sensor 1, applied to the tension servo preamplifier 19, and compared with a reference voltage applied via the tension adjustment variable resistor 20. The voltage corresponding to the position of the sensing post 5 taken out from the amplifier 19 is applied to the servo amplifier 171 together with the output voltage of the discreet circuit 141 via the switch 7 and mixed, and then applied to the TI brake 22 via the drive amplifier 181. The rotation speed of the capstan 31 is controlled so that the tape tension is at an optimum value.

That is, when the running mode is set, if the tension of the tape 6 is smaller than the optimum value, the sensing host 5 is located in the direction of arrow b (a) from the center of the tension sensor 1. Accordingly, a voltage corresponding to this position is extracted from the amplifier 19, and the flywheel 101 is controlled to rotate slower (faster) than the rotational speed at the optimum tension. Therefore, the rotation of the capstan 31 is made slower (faster) than the rotation of the capstan 3z, and the tape 6 is rotated by the take-up side capstan 32 until the optimum tension is reached.
It runs in the direction of winding @11.

By connecting the movable contact piece of the switch 7 to the terminal @, the capstan 3 was rotated at a constant speed under phase control based on the output of the phase comparator 151 and the output of the discretization circuit 141.
1 is switched to rotate at a constant speed by tension control using the output of the amplifier 19 and the output of the discreet circuit 141.

On the other hand, even after the movable contact piece of the switch 7 is connected to the terminal @, the winding side capstan 32 is phase-controlled by the phase error voltage from the phase comparator 152 and rotates at a constant speed.

In this way, in this embodiment, the supply side capstan 3□ is
The speed is controlled using tension control so that the tape tension reaches a preset optimum value, and the speed of the capstan 32 on the first take-up side is controlled using phase control. Wealth can be kept in optimal condition. In addition, since the supply side capstan 31 is switched from the phase control mode to the tension control mode by switching the switch 7, the
When the tape tension is deviated from the set value due to some reason during crimping with the chiller roller, the time until the tension stabilizes can be shortened compared to the conventional method.

Next, a case will be described in which the tape tension is variably set depending on the thickness, type, etc. of the tape.

For example, as shown in FIG. 3, by setting the position of the fixed end P of the spring 21 provided in the tension sensor 1 to be displaced in the direction of the arrow C or the direction of the arrow d, the optimum value is given to the sensing post 5 of the spring 21. Variable tension bias force. In this case, the tension can be controlled to the optimum tension by the above-mentioned tension control so that the sensing post 5 is at the center position of the tension sensor 1, so when the position of the fixed end P is shifted in the direction of the arrow C, the tension is Moreover, it becomes small in the direction of arrow d.

Alternatively, as shown in FIG. 2, the optimum tension position of the sensing post 5 can be changed by variably setting the reference voltage of the amplifier 190 using the variable resistor 20, and the optimum tension position of the spring 21 applied to the sensing post 5 can be changed. Allows tension bias force. In this case, the tension control described above is performed so that the sensing post 5 is at the optimum tension/jon position.

As described above, in this embodiment, the fixed end P of the spring 21
Since the position of the spring 21 and the reference voltage of the amplifier 19 can be set to 8, the effective bias 7 applied to the sensing post 5 of the spring 21 at the optimum tension position can be varied with a simple force configuration, depending on the thickness of the tape, rice variety, etc. The optimum tension value can be selected arbitrarily.

Note that the capstan 31+3m shown in FIG. 2 may be a direct drive or a rim drive in addition to a belt drive.

When applied to a device capable of recording and reproducing in both the forward and backward directions, the tension sensor 1, the sensing post 5, and associated circuits are provided on both the supply side and the winding side, and In mode, capstan 31 is tension controlled, capstan 3
In the bank word direction mode, the capstan 31 is controlled in phase and the tension 32 is controlled in tension, so that these circuits are switched according to the respective modes.

The above embodiment has a configuration in which the two capstans 31 and 32 are driven by the respective motors 8+ and 82.
Next, a configuration in which two capstans 31+32 are driven by one motor will be described. In FIG. 4, 8 is a capstan drive motor, and between the motor 8 and the supply side flywheel 101 there is a relatively large slippage of the belt 231%, and between the motor 8 and the take-up side flywheel 102 there is no slippage. Relatively small belts 23 are wrapped with snow. The motor 8 has a configuration to which a phase error voltage is applied from a drive amplifier 183 provided on the winding side, and the other configurations are the same as that shown in the second figure.

This motor rotates the motor 8 under phase control based on a signal from the winding side applied via the drive amplifier 188, and the drive amplifier 18. The rotation of the flywheel 101 is controlled by a tension control signal applied from the supply side via the brake belt 231, and slippage occurs in the belt 231 due to the braking action of the electromagnetic brake 4. The other operations are the same as those shown in the second figure, so their explanation will be omitted.

On the other hand, the one shown in FIG.
2 is directly driven by a drive motor 8. In the figure, reference numeral 24 denotes a relatively large sliding belt, which is wound between the flywheel 101 and the flywheel 10. The other configurations are similar to those shown in the second figure.

This one has a drive amplifier of 18! The foam-containing side flywheel 102 is directly driven with phase control by the IMM applied from the extractor via the drive amplifier 18.
The rotation of the flywheel 101 is controlled by a tension control signal from the supply side which is input through the Km brake 22, and slippage occurs in the seatbelt 24 due to the braking action of the Km brake 22. The other operations are the same as those shown in the second figure, so their explanation will be omitted.

In each of the above embodiments, the switch 7 is provided on the supply side to perform phase control and tension control in the tape stop mode and the tape running mode, respectively, but if the accuracy of the running speed is not required to be so high, the switch 7,
Oscillator 16, phase comparator 151, 15. It is also possible to omit the above and simply perform speed control and tension control.

Further, the tension sensor 1 and the sensing host 5 are not limited to the configuration provided on the supply side, but may be provided on the winding side.

As described above, the tape tension control method according to the present invention detects the increase in the tension of the tape-shaped recording medium between the tape supply side capstan and the tape winding side capstan, and adjusts the tension accordingly. Obtain the tension control signal
Since the tension control signal is supplied to the brake means provided on the tape supply capstan so that the tension becomes a preset optimum tension, the rotation speed of the supply capstan is controlled. When applied to a capstan type magnetic recording/reproducing device, the tape tension can always be maintained at an optimal state compared to conventional devices that do not perform such tension control, and can be applied to, for example, belt drive type devices. In this case, even if the belt is uneven or changes over time, there is no risk of the tension deviating from the optimal state and causing wow or black as with conventional devices, and it can record and play back with high precision. has.

[Brief explanation of the drawing]

1 and 2 are a schematic plan view and a schematic circuit diagram of the main parts of a magnetic recording/reproducing device to which an embodiment of the present invention can be applied, respectively, and FIG. 3 is a schematic plan view of a magnetic recording/reproducing device to which an embodiment of the present invention can be applied, and FIG. Schematic diagrams for explaining the case of bias force 't I=J variable setting, Figures 4 and 5
The figure is a schematic circuit diagram for explaining another embodiment of the system of the present invention. 1... Tension sensor b 31... Supply side capstan, 32... Winding side capstan, 5... Sensing post, 6... Magnetic tape, 81... Supply side capstan motor, 82... Take-up side capstan motor, 101... Supply side flywheel, 12. ．． 1
22...FG head, 14, ,14. ...Discri circuit, 15. , 152...Phase ratio softener, 1
6... Oscillator, 19... Tension servo preamplifier, 21... Spring, 22... Electromagnetic brake.

Claims (1)

[Claims] Detecting the magnitude of tension in a tape-shaped recording medium between a tape supply capstan and a tape winding capstan, and obtaining a tension control signal corresponding to the magnitude;
A tape characterized in that the tension control signal is supplied to a brake means provided on the tape supply side capstan to control the rotational speed of the supply side capstan so that the tension becomes a preset optimum tension. Tension control method.