JP3105560B2 - Tape tension control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape tension control device, and more particularly to a tape tension control device suitable for a tape traveling device such as a tape recorder or a magnetic tape winding device for winding a magnetic tape around a hub at a high speed. Related to the device.

[0002]

2. Description of the Related Art Conventionally, when a magnetic tape (hereinafter referred to as "tape") is run by a tape running device such as a tape recorder, a tape tension control device is used for the purpose of stabilizing the running of the tape.

In this type of conventional device, a tension arm supported rotatably and urged in one direction by a spring or the like, and a rotation shaft are arranged so as to interlock with the rotation of the tension arm. An output voltage is determined by the rotation position of the tension arm, for example, a potentiometer, a guide roller provided on the tension arm and facing the running area of the tape, and a motor as a drive source for running the tape. And a take-up reel rotated by this motor.

In this conventional device, the tape is
It is driven to run by a motor and is wound on a take-up reel while contacting a guide roller on a tension arm. Then, the tension arm rotates by increasing or decreasing the tension of the tape, and the potentiometer sends out an output voltage corresponding to the rotation position, and controls the rotation speed of the motor by applying the output voltage to the motor. That is, the tension of the tape is controlled.

By the way, in a tape recorder or the like,
When sudden acceleration / deceleration or a large force due to disturbance is applied to the tape traveling system, the voltage for controlling the motor changes greatly, and the tape may be damaged. Therefore, conventionally, by adding the output voltage of the potentiometer of the tape tension control device and a voltage obtained by differentiating the output voltage, when a large change occurs, the gain of the control system is increased so that a sudden change is made. The motor was configured to be compatible.

[0006]

When the tension of the tape set in the above-described conventional tape tension control device is large to some extent, stable tape running can be obtained by this tape tension control device.

However, when the tension arm rotates, it is necessary to run the tape with a weak tension whose mass cannot be ignored. For example, when a thin tape such as an audio cassette tape is run. Therefore, it is difficult to obtain stable tape running with the above-described conventional apparatus. This is because the tension arm moves in the direction opposite to the biasing force of the spring when the tension of the tape is increased, so that the tension arm has good followability, but when the tape tension is weakened, the tension arm Moves in the direction of the biasing force of the spring, so that the followability is deteriorated. That is, when the tension of the tape becomes weak, the tension arm rotates with a delay with respect to the looseness of the tape. In other words, when the tape is in the loosening direction, the rotation of the tension arm depends only on the urging force of the spring, so that the followability is deteriorated.

In the case of a device in which the tension setting of the tape is particularly weak, the force of the spring must also be set to a low value corresponding to the tension, and in such a case, the influence of the inertia force of the tension arm is required. become. As a result, the control of the tape tension is delayed, so that the tape tension becomes too weak before the tension arm follows, or the motor rotates in the reverse direction. Further, in order to avoid such a phenomenon, if the differential correction amount of the differential correction circuit is increased or the gain of the control system is increased, a problem such as hunting is likely to occur.

SUMMARY OF THE INVENTION An object of the present invention is to provide a tape tension control device capable of obtaining a stable tape running regardless of the strength of the tension.

[Structure of the Invention]

[0011]

A tape tension control device according to the present invention includes a displacement member which is displaced in response to a change in the tension of a tape driven by a drive source, and an output signal corresponding to the displacement position of the displacement member. A position detecting means for transmitting, and a differential for taking in an output signal from the position detecting means and transmitting a small output signal which is small when the tension of the tape is increased and large when the tension of the tape is decreased. And a correction circuit, wherein a signal obtained by superimposing the output signal and the differential output signal is supplied as a drive signal to the drive source to control the tension of the tape.

[0012]

The operation of the above-described tape tension control device will be described below.

The displacement member in the tape tension control device is displaced in accordance with a change in the tension of the tape driven by the drive source. At this time, the position detecting means sends an output signal corresponding to the displacement position of the displacement member. Further, differential correction circuit receives the output signal from said position detecting means, before small when the increase in the tension of the Kite-loop and sends a large differential output signal at the time of reduction of the tape tension.

As a result, the differential output signal corresponding to the increase or decrease of the tape tension is superimposed on the output signal of the position detecting means, and this is supplied to the drive source as a drive signal. Appropriately controlled accordingly.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a tape tension control device 1 according to an embodiment of the present invention.

A tape tension control device 1 shown in FIG. 1 is formed in a substantially rectangular parallelepiped shape, and has a tension arm 21 as a displacement member whose one end is rotatably supported by a bearing or the like (not shown). A guide roller 3 rotatably arranged at the other end and facing the running area of the tape 4, a spring 5 for applying a biasing force in the direction of arrow a to the tension arm 21, and one end of the tension arm 21 And a shaft 2a that rotates in conjunction with the rotation of the tension arm 21, and detects a rotation state of the tension arm 21, that is, a position that outputs a linear (linear) output voltage according to the displacement position of the tension arm 21. A potentiometer 2 as a means,
A first amplifying output voltage from the potentiometer 2
, An output voltage amplified by the first amplifier 8, a differential correction circuit 9 for performing a differentiation process and sending out a differential output voltage, and transmitting the output voltage amplified by the first amplifier 8. And a second amplifier 11 for superimposing and amplifying the output voltage and the differential output voltage and applying the amplified result as a drive voltage (drive signal) to a motor 7 as a drive source for driving the tape 4. Is provided. The take-up reel 6 shown in FIG. 1 is attached to the motor 7 and takes up the tape 4 as the motor 7 rotates.

Next, the circuit configuration of the differential correction circuit 9 will be described.

The variable resistor 12 in the differential correction circuit 9
Adjusts the output voltage from the first amplifier 8. The capacitor 13 and the resistor 14 and the capacitor 15 and the resistor 16 connected to the variable resistor 12 differentiate the output voltage from the variable resistor 12, respectively. At this time, these time constants are set so that the differential output voltage by the capacitor 15 and the resistor 16 becomes smaller in accordance with the linear output voltage corresponding to the displacement position of the tension arm 21 accompanying the increase in the tension of the tape 4. Is set. In addition, these time constants are set so that the differential output voltage by the capacitor 13 and the resistor 14 increases in accordance with the linear output voltage corresponding to the displacement position of the tension arm 21 due to the decrease in the tension of the tape 4. Have been.

The diode 18 connected to the capacitor 15 passes a positive component of the differential output voltage by the capacitor 15 and the resistor 16. The diode 17 connected to the capacitor 13
Pass through the negative component of the differential output voltage by the capacitor 13 and the resistor 17.

Next, the tape tension control device 1 having the above-described configuration.
Will be described.

The tape 4 driven by the motor 7
Runs while contacting the guide roller 3 provided on the tension arm 21, and is wound by the winding reel 6. At this time, if the tension of the tape 4 increases due to disturbance or the like, the tension arm 2
1 rotates in a direction (b direction) opposite to the urging force of the spring 5. Conversely, when the tension of the tape 4 decreases, the tension arm 21 rotates in the direction of the urging force of the spring 5 (direction a) due to the decrease in the tension.

With the rotation of the tension arm 21, the shaft 2 a of the potentiometer 2 also rotates, whereby the potentiometer 2 sends out a linear output voltage according to the displacement position of the tension arm 21.

The first amplifier 8 amplifies the output voltage from the potentiometer 2 to a level that can be electrically processed, and sends the amplified voltage to the resistor 10 and the differential correction circuit 9.

The differential correction circuit 9 takes in the output voltage from the first amplifier 8, and as described above, the differential output voltage decreases as the tension of the tape 4 increases, and the differential output voltage decreases. When the tension decreases, the differential processing is executed so that the differential output voltage increases.

Then, the output voltage from the first amplifier 8 via the resistor 10 and the differential output voltage from the differential correction circuit 9 are superimposed and amplified by the second amplifier 11, and the amplification result is the driving voltage. Is applied to the motor 7.

In this manner, when the tension of the tape increases, a small differential output voltage obtained by differentiating the output voltage is superimposed on the output voltage from the potentiometer 2 for detecting the rotation stop position of the tension arm 21. When the tension of the motor 7 decreases, a large differential output voltage obtained by differentiating the output voltage is superimposed, and these are applied as drive voltages to the motor 7 to control the rotation of the motor 7.

Accordingly, even when the tension arm 21 cannot sufficiently follow the change in the tension of the tape 4, the magnitude of the acceleration of the tension arm 21, ie, the output voltage of the potentiometer 2, even when the set value of the tension of the tape 4 is small. Is added to correct the portion where the tension arm 21 cannot follow, and the rotation of the motor 7 corresponding to the actual tension of the tape 4 can be controlled. As a result, in a tape traveling device such as a tape recorder or a magnetic tape winding device, it is possible to realize a stable tape traveling state regardless of the strength of the tape 4.

In this embodiment, the capacitor 1
Since the circuit element that differentiates by the resistance 5 and the resistor 16 and allows the positive voltage to pass through the diode 18 performs correction when the tension of the tape 4 increases, the circuit element is configured by the capacitor 13 and the resistor 14 that allow the negative voltage to pass. Also, the time constant is set so that the correction amount is small.
5 and the resistor 16 can be eliminated. This is because when the tension of the tape 4 increases, the tension arm 21 follows the change in the tension irrespective of the magnitude of the set value of the tension, so that little correction is required.

Further, the tape tension control device 1 of the present embodiment
Is applicable not only when the tension setting of the tape 4 is weak, but also when the tape 4 runs at high speed.

The present invention is not limited to the embodiment described above, and various modifications can be made within the scope of the present invention.

For example, in the present embodiment, the amount of correction of the output voltage is changed between when the tension increases and when the tension decreases by making the time constant in the differential correction circuit 9 different. The correction amount may be changed by providing a variable resistor at a stage subsequent to each of the diodes 17 and 18.

[0033]

According to the present invention described in detail above, with the above-described configuration, a tape capable of performing appropriate tension control according to a change in the tension of the tape regardless of the strength of the tape. A tension control device can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram of a tape tension control device according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tape tension control device 2 Potentiometer 7 Motor 9 Differential correction circuit 21 Tension arm

Claims (1)

(57) [Claims] 1. A displacement member that is displaced in response to a change in the tension of a tape driven by a drive source, a position detection unit that sends an output signal corresponding to a displacement position of the displacement member, and a signal from the position detection unit. The output signal is captured, and it is small when the tape tension increases, and large when the tape tension decreases.
; And a differential correction circuit for delivering heard differential output signal,
A tape tension control device, wherein a signal obtained by superimposing the output signal and the differential output signal is supplied to the drive source as a drive signal to control the tension of the tape.