JPS58208953A - Tape tension control system - Google Patents

Abstract

PURPOSE:To select an optimum value of tension arbitrarily with a simple constitution, by setting a position of a fixed end of a spring and a reference voltage of an amplifier variably respectively. 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 winding 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 tape tension is controlled by applying the tension control signal to a tape supply side capstan driving motor 81 to control the rotating speed of the motor 81 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, which directly controls the rotation speed of a capstan drive motor on the supply side so that the tape tension is optimized 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 always maintain tape tension in an optimal state.

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 IJ'+ 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 made smaller than that of the capstan motor on the take-up side. Drive each 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 body for the belt that wraps around the capstan, use flywheels with different driving powers for each capstan, or use a non-repulsory belt to create diameter differences between each capstan or flywheel. The circumferential speed of Tenju's capstan motors is varied depending on the method, such as whether different types are used. For this reason, this belt has disadvantages in that it tends to cause wow and flutter when maintaining a predetermined capstan circumferential speed due to non-uniformity of the belt and elongation due to aging.

On the other hand, the latter method does not have the problem of the bell HC like the method using one drive motor mentioned above, but if the tape tension deviates from the set value for some reason due to the large mechanical impedance of the capstan, the set value The disadvantage was that it took a long time to return to normal.

In addition, both methods have drawbacks such as the long time it takes from when the pinch roller is crimped to when the tape tension stabilizes, and furthermore, it is difficult to configure the tape tension to be set variably in accordance with the thickness and type of magnetic tape. There were drawbacks such as difficulty.

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 part that covers the shoulder is given the same number. In the same figure, IF
The i tension sensor connects the % supply via fo-ra 21, the supply side capstan 31, and the supply side guide roller 4I.
It is fixed between. A sensing post 5 is supported on the upper surface of the tension sensor 1 so as to be able to move in the directions of arrows a and b according to the tension of the magnetic tape 6.
There is.

When the tape tension is at the optimum value, the sensing post 5 is set to be located at the center of the displacement range of the tension sensor 1, and resists the elastic force of the spring provided in the tension sensor 1. When the tape tension is larger than the optimum value by υ, it is set to move to the arrow a side, and when it is smaller than that, it is set to move to the arrow b II+.

The tension sensor 1 is constructed so that a voltage of a magnitude corresponding to the displacement of the sensing post 5 in the directions of arrows a and b is extracted based on the case where the tension is at an optimum value.

First, in the tape stop mode, the supply side *
When driving the Yapstan 31 and the winding-side capstan 32 at a constant speed by phase control, the movable contact piece of the switch 7 is connected to the terminal (2). The supply side capstan drive motor 81 is driven to rotate at its rotation speed 9. The supply side flywheel l0IK is transmitted through the flywheel]0
Pulses proportional to the rotational speed of the motor 81 are extracted by opposing the pulse wheel 111 and the FG head 121 provided in the motor 81 . This pulse is amplified by an amplifier 131 and sent to the edge discreet circuit 14. The signal is converted into a loud voltage according to the frequency and supplied to the servo amplifier 171, and is also supplied to the phase comparator 151.

-The reference pulse of the oscillator 16 is the phase comparator 15.
1, the phase comparison error voltage corresponding to the phase difference between the two pulses is taken out from the phase comparator 51 and applied to the servo amplifier 171 via the switch 7. In the servo amplifier 171, the voltage corresponding to the rotational speed of the motor 81 from the discretization circuit 141 and the phase comparison error voltage from the phase comparator 151 are mixed and applied to the motor 8 via the drive amplifier 181. be done. Here, the capstan 31 is connected to the drive amplifier 181.
It rotates at a constant speed under phase control using a phase error voltage.

- The take-up side capstan 32 also rotates at a constant speed under phase control in the same way as the supply side capstan 31. j! !
The rotation of the winding motor 82 is controlled by the belt 9.
2 through the flywheel 10. The pulse wheel 112 and the FG head 12! The pulses thus obtained are supplied to the discretization circuit 142 and the phase comparator 15 via the amplifier 132. Phase comparator 15! The output voltage from the servo amplifier 172 and the output voltage from the discret circuit 142 are mixed by the servo amplifier 172 and then the output voltage from the HA amplifier 182.
Motor 8 through! is applied to the capstan 32, thereby controlling the phase of the capstan 32.

Here, the movable contact piece of the switch 7 is connected to the terminal (b) to set the tape running mode, for example, the recording mode.

In this case, a voltage corresponding to the position of the sensing post 5 is taken out from the tension sensor 1, and is applied to the tension servo preamplifier 9 and then applied to the tension adjustment variable resistor 2.
is compared to a reference voltage applied via o. Amplifier 1
The voltage corresponding to the position of the sensing post 5 taken out from the sensor post 9 is applied to the servo amplifier 171 together with the output voltage of the discreet circuit 141 via the switch 7 and mixed, and is applied to the motor 81 via the drive amplifier 181. The rotation speed of the capstan 31 is controlled so that the tape tension is at an optimum value.

When the tension of the tape 6 is smaller (larger) than the optimum value when the running mode is set, the sensing post 5 moves from the center of the tension sensor 1 as shown by arrow b (a).
in the direction. As a result, a voltage corresponding to this position is extracted from the amplifier 19, and the motor 81 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 32, and the tape 6 is run toward the take-up side by the take-up side capstan 32 until the tape 6 reaches the optimum tension. By connecting the movable contact piece to the terminal @.

Phase comparator 15. The capstan 31, which has been rotated at a constant speed with phase control based on the output of the amplifier 19 and the output of the discreet circuit 14.
It is switched to rotate at a constant speed using tension control based on the output of .

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 ratio of 11Hjt15g and rotates at a constant speed.

In this way, in this embodiment, the supply side capstan 31 is
The speed is controlled by tension control so that the tape tension is at a preset optimum value, and the speed of the take-up capstan 32 is controlled by phase control. It can always be maintained in an optimal state. 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 tape tension may deviate from the set value due to some reason during pinch roller crimping. In some cases, the time required to stabilize the tension 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, the sensing post 5 of the spring 21 can be set by displacing the fixed end P of the spring 21 provided in the tension sensor 1 in the direction of arrow C or the direction of arrow d. The optimum tension applied to the 7-ear force is varied. In this case, the tension is controlled so that the optimal tension is achieved by the tension control described above so that the sensing post 5 is located at the center position of the tension sensor 1. Therefore, when the position of the fixed end P is moved in the direction of arrow C, the tension is and becomes smaller in the direction of arrow d.

Alternatively, as shown in FIG. 2, by variably setting the reference voltage of the amplifier 19 using the variable resistor 20, the optimum tension/position of the p1 sensing post 5 can be varied and the sensing post 5 of the spring 21 can be adjusted. Variable bias force for optimal tension. In this case, the tension is controlled by the tension control described above so that the sensing post 5 is at the optimum tension position.

As described above, in this embodiment, the fixed end P of the spring 21
The position of and the reference voltage of the amplifier 19 are set to bJK, respectively'! Sensing post 5 of the spring 21 at the optimum tension position with a simple configuration
The effective bias force applied to the tape can be varied, and the optimal tension value can be arbitrarily selected depending on the thickness and type of tape.

In addition, in FIG. 2, when the drive motor 81 is a hysteresis h sub-motor, the circuit near the servo amplifier 171 on the supply side may be configured as shown in FIG. 4.

That is, the voltage from the phase comparator 151 or the amplifier 19 is applied to the voltage controlled oscillator (VCO) 22 via the switch 7 to obtain a pulse signal with a frequency corresponding to the input voltage and supply it to the position adjuster 23. On the other hand, a voltage corresponding to the rotational speed of the motor 81 from the discreet circuit 141 is applied to the phase modulator 2.
3 to obtain a phase comparison error voltage or tension control voltage, which is applied to the motor 81 via the amplifier 24. The operation is similar to that shown in FIG.

Further, the capstans 31 and 32 shown in FIG. 2 may be of a direct drive or a rim drive in addition to a belt drive.

Further, in the embodiment shown in FIG. 2, a 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 in cases where the accuracy of the running speed is not required to be so high Alternatively, the switch 7, the oscillator 16, the phase comparators 151+152, etc. may be omitted, and the configuration may be such that simple speed control and tension control are performed.

In addition, the tension sensor 1 and sensing post 5 are supplied (
It is not limited to the configuration provided in till, and %]f
, may be provided on the side.

Also, when applied to a device capable of recording and reproducing in both forward and backward directions.

Tension sensor 1. A sensing post 5 and associated circuits are provided on both the supply side and the winding side, and in the forward direction mode, the capstan 31 tension control,
The phase of the capstan 32 is controlled, and in the backward direction mode, the capstan 3+ * phase In control,
The configuration may be such that these circuits are changed according to each mode so that the tension 3□ is controlled (tension control).

Alternatively, if the tension sensor is placed between the forward direction head and the puncture direction head, and the tension sensor is switched as described above, it is possible to use one sensor for both directions.

As described above, the tape tension control method according to the present invention detects the height of the tension of the tape-shaped recording body between the tape supply side capstan and the tape winding side 11 capstan, and controls the tape tension control method according to the present invention. A tension control signal corresponding to the tension is obtained, and the tension control signal is supplied to the tape supply side capstan drive motor to control the rotation speed of this motor so that the tension becomes the preset optimum tension. When applied to a capstan-type tape recording/playback device, the tape tension can always be maintained at an optimal state compared to conventional devices that do not perform such tension control, and for example, it is possible to maintain the tape tension at an optimal state, such as in a belt-drive type device. When applied to a belt, even if there is unevenness in the belt or changes over time, there is no risk of the tension deviating from the optimal state and causing wow or flutter, as with conventional devices, and recording and playback can be performed with high precision. It has the following features.

[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 that can be used in one embodiment of the present invention, respectively, and FIG. 3 shows a tension sensor spring attached to a sensing post. FIG. 4 is a schematic diagram for explaining the case where the applied bias force is variably set. FIG. 4 is a schematic circuit diagram for explaining another embodiment for driving and controlling the supply side capstan motor. DESCRIPTION OF SYMBOLS 1... Tension sensor, 31... Supply side capstan, 32... Winding side capstan, 5... Sensing post, 6... Magnetic tape, 81... Supply side capstan motor, 82... Winding side capstan motor 5121+122... FG head, 14. ．． 14.
... Discrete circuit, 1511152 ... Phase comparator, 16 ... Oscillator, 19 ... Tenyon servo preamplifier, 21 ... Spring. Figure 1 Figure 3 Figure 4 289-

Claims (1)

[Claims] The magnitude of the tension in the tape-shaped recording medium between the tape supply side capstan and the tape winding side capstan is detected, a tension control signal corresponding to the magnitude is obtained, and the tension is set to the optimum level in advance. A tape tension control method characterized in that the tension control signal is supplied to a tape supply side capstan drive motor to control the rotational speed of the motor so as to maintain tension.