JPS6190356A - Magnetic tape tension control device - Google Patents

Abstract

PURPOSE:To control the tape tension at low tension, by providing a brake means to a reel motor and controlling the load torque of reel motor of sending side by changing the load fed to the reel by the brake means according to the tension of the magnetic tape at rapid traverse/rewinding. CONSTITUTION:The FG output from a reel motor 1 of winding side is supplied to a trapezoidal waveform formation circuit 32 and a sample pulse generating circuit 33 through a switch 37 and after amplified by an FG amplifier 31. The trapezoidal wave output of the trapezoidal waveform formation circuit 32 and the sample pulse output of the sample pulse generating circuit 33 are supplied to a sample hold circuit 34, and the sample hold output is supplied to a motor drive circuit 20. Hereafter, the same action is attained at the reel motor 2 of supplying side, and the reel motor 1 of winding side is controlled in its rotation speed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is an apparatus for recording and reproducing television signals on a magnetic tape, and the tape tension control of the magnetic tape during fast forwarding or rewinding of the magnetic tape is performed on the forwarding and unwinding sides. The present invention relates to a magnetic recording/reproducing device configured to perform operations by changing the load (braking force) on the reel.

Conventional configuration and its problems In magnetic recording and reproducing devices, magnetic tape fast forwarding (hereinafter referred to as F
When rewinding (hereinafter referred to as "F") or rewinding (hereinafter referred to as "REW"), the capstan motor and pinch roller are usually not used, but tape running and tape tension are controlled by a reel motor (hereinafter referred to as reel servo). . Figures 1 and 2 show the feeding system (tape path) and block diagram of a conventional reel servo system.
The EW time is illustrated a).

The operation of the tape running control and tension control system of the conventional glue servo system will be described using FIG. 1 and FIG. 2 (the phase control system is omitted in FIG. 2a). The operation of the traveling control thread will be explained. 1 is a take-up side reel motor, and 2 is a supply side reel motor. The tape running system changes from stop mode to REW mode (
mode mechanism is not shown), the magnetic tape 6 runs in the direction of the arrow. At this time, the timer roller 4 in contact with the magnetic tape 5 rotates. The timer roller 4 is constituted by a photo encoder or a magnetic type, and is configured to generate pulses (frequency) corresponding to the running speed of the magnetic tape (its structure is not shown). The pulses obtained from the timer roller 4 according to the running speed of the magnetic tape 5 are amplified by a pulse amplifier 6, and the outputs thereof are supplied to a trapezoidal wave forming circuit 7 and a sample pulse generating circuit 8, respectively. The output of the trapezoidal wave forming circuit 7 and the output of the sample pulse generating circuit 8 are supplied to a sample hold circuit 9 to obtain a sample hold output, and the output is supplied to a motor drive circuit 10.

The output of the motor drive circuit 1o is supplied to the supply reel motor 2, and the rotation speed of the supply reel motor 2 is controlled so that the pulses (revolution speed) of the timer roller 4 are constant.

On the other hand, for tension; (The configuration is not shown) is amplified by an amplifier 11, the tension is set by a tension setting circuit 12, and the output is supplied to a motor drive circuit 13 to control the number of rotations of the reel motor 10 on the winding side. In this case, as shown in FIG. 1, the rotation direction of the supply side reel motor 2 is configured to change the magnitude of the bank tension, and the tension is controlled by controlling the rotation speed of the take-up side reel motor 1. can be done. In the case of conventional coated magnetic tape, the tension at the entrance side of cylinder 3 (Fig. 1A) is 3Q±.
The reel motor part (B and C in Figure 1) should be set to about 5gr, and therefore the reel motor part (B and C in Figure 1) should be about 10 to 20gr, although it differs depending on the configuration of the tape running path, and even with the tension control method described above, tension control is sufficient. I can do it. However, if the thickness of the magnetic tape becomes thinner or
In the case of vapor-deposited tape, it is not possible to apply a large tape tension, and the above-mentioned cylinder entry side (Fig. 1A)
), and therefore the reel motor portion (FIG. 1B, C) has a pressure of about 0 to -10 gr, making it impossible to control the tension using the above-mentioned tension control method.

Purpose of the Invention The present invention uses a reel servo system to control the tension of the magnetic tape during fast forwarding or rewinding by controlling the load on the reel on the feed side and the reel, thereby providing a stable magnetic tape tension control system even when the tension is low. The purpose is to provide

Structure of the Invention In order to achieve the above object, the present invention provides a reel motor with a brake means, and when driving fast forward or rewind, the load of the brake means applied to the reel is changed according to the tension of the magnetic tape, thereby reducing the load on the reel on the sending side. By controlling the load torque of the motor, a tape tension control tube can be created at low tension.

Description of examples An embodiment of the present invention will be shown and its operation will be explained.

Among the embodiments of the present invention, those that perform the same operations as those shown in the conventional example are given the same numbers as in the conventional example. Fig. 3 is a diagram showing a magnetic tape running system (tape path) according to an embodiment of the present invention, and Fig. 4 is a diagram showing a magnetic tape running system (tape path) according to an embodiment of the present invention. Figure 5 is a block diagram showing the configuration of this embodiment, and Figures 6 and 7 are diagrams showing the principle of torque generation using a motor. The operation of the control system will be explained (the phase system will be omitted). When the tape running system enters the stop mode J:REW mode (the mode switching mechanism is not shown), the operation will be explained as described in the conventional example. The magnetic tape 5 runs in the direction of the arrow. At this time, the pulse obtained from the timer roller 4 in contact with the magnetic chill processor according to the running speed of the magnetic tape 6 is amplified by the pulse amplifier 6, and its output is sent to the trapezoidal waveforming circuit 7 and the sample pulse, respectively. The signal is supplied to the generating circuit 8. The trapezoidal wave output of the trapezoidal wave forming circuit 7 and the sample pulse output of the sample pulse generating circuit 8 are supplied to the sample hold circuit 9, and the sample hold output is sent to the switch 36.
is supplied to one input terminal of the comparator 25 of the motor 1 drive circuit 2Q.

The reel motor used in the present invention is a DD brushless motor, and its driving method is to detect the rotational position with a position detector 21, apply its output to a 3-differential switching circuit 22, and apply it to a current amplification circuit 23 and It is a three-phase drive blade type in which the output stages of the motor drive circuit 24 are sequentially switched to drive one rotation of the brushless motor. The motor load current detected as a voltage by the current detection resistor 26 is applied to the other input terminal of the comparator 25, and the motor load current detected as a voltage by the current detection resistor 26 is applied to the other input terminal of the comparator 25.
is compared with the output from . The running speed of the magnetic tape can be controlled to be constant by performing torque control based on the comparison result and controlling the rotational speed of the supply side reel motor 2.

On the other hand, the reel motor 1 on the take-up side is rotated at an appropriate rotation speed so that its rotation direction is the feed-out direction.

In FIG. 6, the FG ratio output from the take-up reel motor 1 is amplified by the FG amplifier 31 via the switch 37, and is supplied to the trapezoidal wave forming circuit 32 and the sample pulse generating circuit 33, respectively.

The trapezoidal wave output of the trapezoidal wave forming circuit 32 and the sample pulse output of the sample pulse generating circuit 33 are supplied to the sample hold circuit 34, and the sample hold output is supplied to the motor drive circuit 20 via the switch 36, and the subsequent operation is performed on the supply side. It operates in the same manner as the reel motor 2, and the rotational speed of the take-up reel motor 1 is controlled. At this time, torque T2 is generated in the feeding direction (FIG. 8).

Before explaining the operation of the tension control system, we will describe the generation of load (brake) torque using the motor shown in one embodiment of the present invention. (referred to as T characteristics) and motor load (winding) current. Now, when the motor is rotated by an external means as shown in Fig. 4, the motor (motor 18 or 19 in Fig. 4) has two ends of the windings.
An induced voltage (power generation) occurs at 7.28 or 29.30. This induced voltage is E, M, and the winding resistance of the motor is Ra (ω). The resistance Ra (Ω) connected to the winding terminal of the motor is
In the case of Fig. 7), the electric current flowing through the motor is I, = EM/Ra+R1...
・・・・・・・・・・・・・・・It is expressed as (1). The motor torque at this time is a torque T1 corresponding to the winding current 11 when the motor is rotated as shown in FIG.

Therefore, by varying R1 in equation (1) above, the load torque T1 of the motor can be changed, and as shown in FIG.・・・・・・・・・・・・
(21) However, it is r-tape radius, and tape tension can be controlled.

Next, the operation of the tension control system will be explained. A signal corresponding to the position of the tension arm is obtained by the tension detector 16, amplified by the amplifier 11, tension set by the tension setting circuit 12, and its output is supplied to the load control circuit 31.

The variable load resistance circuit 32 changes the load resistance connected to both ends of the brake motor 19 via the switch 36 in accordance with the output voltage of the load control circuit 31. As shown in FIG. 4, the brake motors 18 and 19 are connected to the reel motors 1 and 2 via couplings 16 and 17, and in the REW mode, the load torque of the brake motor 19 is This causes the back tension of the magnetic tape 5 to be controlled. Therefore, tape tension can be controlled.

In the case of the present invention, a motor is directly connected as a braking means, but it is also possible to provide a brake winding in the reel motor or to electrically control the braking force of the tension band by using a mechanical iCf7 tension band. The same effect can be obtained using other methods.

In addition, in the case of FF mode, switch 35, 36.37
By switching 9, tape running control and tension control can be performed in the same manner as in the REW mode. Further, the same operation can be performed even if the reel motor is a brush motor.

Effects of the Invention (1) By adopting the structure of the present invention, a stable tape running system can be achieved in running a low-tension magnetic tape.

((2) A uniform load is applied during one rotation without any change in load during one rotation, unlike in a configuration where a load is applied by mechanically pressing the bat against the reel stand.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the magnetic tape running system (C tape path), Fig. 2 is a block diagram for explaining the operation of the magnetic tape running control system and tension control system in the running system of Fig. 1, and Fig. 3 4 is a schematic diagram showing a tape running system of the present invention, FIG. 4 is a diagram showing a part of the configuration of a reel stand in an embodiment of the present invention, and FIG. 5 is a block diagram of a running control system and a tension control system of the present invention. 6, 7, and 8 are diagrams for explaining the operating principle of the embodiment of the present invention. 1... Take-up side reel motor, 2... Supply side reel motor, 14.15... Tension detector, 18.19... Brake motor . Name of agent: Patent attorney Toshio Nakao and 1 other person: jS1 Figure 2 Figure 6 6 ± kal b) Figure 3 Figure 5154

Claims (4)

[Claims] (1) A supply reel motor and a take-up reel motor for rewinding or fast-forwarding the magnetic tape, a first brake means for applying a load torque to the supply reel motor, and the take-up reel motor. a second brake means for applying a load torque to the side reel motor; a first tension detection means for detecting the tape tension of the supply side reel; and a first tension detection means for detecting the tape tension of the take-up side reel. a second tension detection means is provided, and the output of the first tension detection means is supplied to the second brake means during the rewinding drive;
During the fast-forward driving, the output of the second tension detection means is supplied to the first brake means, and the output of the second tension detection means is supplied to the first brake means.
A magnetic tape tension control device, characterized in that it is configured to control the load torque of the second braking means. (2) The magnetic tape tension control device according to claim 1, wherein the load torque of the brake means is controlled using a variable resistor. (3) The magnetic arc tension control device according to claim 1, wherein a DC motor is used as the braking means. (4) The magnetic tape tension control device according to claim 1, wherein the brake means is built into the reel drive motor.