JPS5914170A - Tape tension controller - Google Patents

Abstract

PURPOSE:To ensure a stable control of tape tension, by controlling the motor of a reel at the tape feeding side in response to the difference between the converted voltage corresponding to the tape tension and the constant voltage. CONSTITUTION:The voltage corresponding to the detected tape tension delivered via a pickup part 9, a voltage converting circuit 47, a power amplifier circuit 18, etc. is higher than the output voltage of a constant voltage circuit 19 when the load is normal. Thus the rotary power is applied as the damping power to a driving motor M2 of a reel at the tape feeding side. While the control voltage of the motor M2 is set backward to control the tape feed when the load is heavy with increase of the tape tension. This ensures a stable control of tape tension without giving any effect to the load.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a tape tension control device, and for example, to a tape tension control device in a magnetic recording/reproducing device having a take-up reel motor and a supply reel motor.

[Technical background of the invention]

To run the magnetic tape 2 in a magnetic recording/reproducing device (hereinafter referred to as a VTR) (including tape decks and magnetic tape devices for audio, video, computer, etc.), for example, as shown in FIG. 1, a take-up reel 3a and a The supply reel 3b is mounted on the take-up reel stand 4a and the supply reel stand 4b of the VTR 1, and a predetermined magnetic tape running path is established.

The take-up reel 3a and the supply reel 3b may be formed integrally with the cassette 3, or may be of an open reel type. In Figure 1! For clarity, the case of cassette 3 is shown. Take-up side reel stand 4a and supply side reel stand 4
b is a take-up side reel motor M1, a supply side reel motor M,
(Not shown. Hereinafter simply referred to as reel motor M, , M)
is driven by. The VTR 1 has running modes such as recording/playback, frame-by-frame forwarding, reverse playback, rewinding, and fast forwarding, and the reel motors Ml, M2 can be controlled by the running speed control mechanism of the pinch roller 7 and capstan 8, or by the running speed control mechanism of the pinch roller 7 and capstan 8. to rotate forward (clockwise) or reverse.

Reel motor M1 or M2 controlled as the sending side
is subjected to tape tension control so as to give an appropriate back tension to the running of the magnetic tape 20.

As shown in FIG. 2, the tape tension control device includes a pickup section 9, a voltage conversion circuit 10, and a power amplification circuit 1.
Consists of 1. The tape tension caused by the running of the magnetic tape 2 is generated by a magnet 12 provided in the pickup section 9.
is detected as the amount of displacement. This amount of displacement becomes the amount of change in the resistance value of the magnetoresistive element 13 and is converted into a voltage by the voltage conversion circuit 10. This converted voltage is power amplified by the power amplifier circuit 11 and outputted from the pin 11a as control power.

One end of the reel motors M1 and M2 is connected to a reference potential point, and the other end is connected to a rotation direction switch 28 that determines whether or not the reel motors M1 and M2 are to be controlled as feeding. Therefore, the control power is supplied to the other end of the reel motor M+ or M2, which is controlled as a feed-out. Through this tape tension control, a predetermined pack tension is applied to the m-stape 2. Therefore, the magnetic tape 2 rotates forward or backward without maintaining the correct running path. When the rotational direction switching signal S is inputted to the rotational direction switching device 28 via the terminal 6, the switching contact 28a is operated, and the take-up side reel motor M is controlled as the feeding side. In this case, the magnetic tape 2 is reversed.

If the rotation direction switching signal No. 8 is not input, the magnetic tape 2
rotates forward and the switching contact 28. is restored, and the supply side reel motor M2 is controlled as the delivery side.

[Problems with background technology]

In the conventional tape tension control device, one end of the reel motor M, which is controlled on the feeding side, is connected to a reference potential point. Further, the current direction of the reel motor Ml or M3 controlled on the feed-out side is fixed, that is, it only applies back tension to the magnetic tape 2. Therefore, if the load becomes heavier than the predetermined pack tension, control becomes impossible. and,
If the running of the magnetic tape 20 becomes pulsating, the magnet 12
Abnormal operation such as vibration may occur, which may result in an accident that may damage the magnetic tape 2.

[Purpose of the invention]

An object of the present invention is to provide a tape tension control device that can perform stable tape tension control even when the load is heavier than the back tension.

[Summary of the invention]

In the present invention, a constant voltage circuit is connected to one end of the take-up side reel motor or the supply side reel motor that is controlled as the sending side.

On the other hand, a detection signal obtained by a magnetic tape tension detection means for detecting tape tension is converted into voltage by a voltage conversion circuit connected to the other end of the motor, and control power is further obtained from this converted voltage. There is. The conversion voltage is set so that the voltage level of this control power flows into or out of the constant voltage circuit.

[Embodiments of the invention]

Hereinafter, one embodiment of the tape tension control device according to the present invention will be described in detail with reference to the drawings.

FIG. 3 is a circuit diagram of an embodiment of the control/control device according to the present invention. The Chibuchi/John control device includes a pickup section 9, a voltage conversion circuit 17, a power amplification circuit 18,
It is composed of a constant voltage circuit 19.

When the rotational direction switching signal S is input through the terminal 6, the switching contacts 24, 25, 26 of the rotational direction switching device 23
．． 27 operates, and the take-up reel motor M+ is controlled as a feed-out side and tape tension controlled.

In this case, the magnetic tape 2 is reversed. When the rotational direction switching signal s4 is not input, the rotational direction switching device 23 is restored and the magnetic tape 2 rotates in the normal direction, and the supply side reel motor M2 is controlled as a feeding side and subjected to tape tension control.

The pickup section 9 is disposed in the running path of the magnetic tape 2 with the cylinder 5 shown in FIG. 1 intervening therebetween. The pink-up section 9 is composed of a magnet 12 and a magnetoresistive element 13, and the resistance value of the magnetoresistive element 13 changes with the displacement value of the magnet 12. This change in resistance value is output to pin 17a of voltage conversion circuit 17 as detection signal SI. As shown in FIG. 4, the pickup section 9 has an arm 16 supported by a shaft 14 and biased in the direction of arrow A by a swing ring 15, and a boss 1 installed at the tip of the arm 16.
6a is in contact with the magnetic tape 2 on the running path. When the tape tension increases, the base portion 16b of the arm 16 is displaced in the direction of arrow B with the support 14 as the center. Base 16b
A magnet 12 is provided, and the displacement of the magnet 12 increases or decreases the resistance value of the magnetoresistive element 13. The increase/decrease in this resistance value is detected by the signal S! It is output to pin 17a of voltage conversion circuit 17 as .

The voltage conversion circuit 17 includes a variable resistor vR1 and an operational amplifier 20. Pin 17. When the detection signal S1 is input to the power amplifier circuit 18, a converted voltage V2 corresponding to the detection signal sI is output to the power amplifier circuit 18. The power amplifier circuit 18 is composed of an operational amplifier 21 and transistors Qs and Qt, and converts the voltage
, is outputted from pin 18a. When the tape tension increases and the base 16b of the arm 16 is displaced in the direction of arrow B, the level of the converted voltage V gradually decreases, and the voltage level of the control power S2 output from pin 1B also decreases. This control power S is applied to the reel motor M1 or M on the sending side via the rotation direction switch 23.
is supplied to the other end of l. Note that the level of the converted voltage (2) is adjusted by the variable resistor VR1.

The constant voltage circuit 19 includes a variable resistor vR2, an operational amplifier 22, and transistors Qj and Q4, and connects a constant voltage S8 to pin 19. Output via. This constant voltage S3 is supplied via the rotation direction switch 23 to one end of the reel motor M11 or M, which is controlled as a feed-out side. Note that this constant voltage S3 is adjusted by a variable resistor vR2. That is,
The maximum allowable tape tension is applied to the magnetic tape 2, and the control power S of the pin 18a is applied! When the voltage level of is set to the minimum, and the level of constant voltage S is gradually increased by operating variable resistor ■R2, the stopped reel motor M+ or M! starts to rotate, so it's about to rotate (so it doesn't rotate)
The constant voltage Ss is set to the level of the constant voltage Ss, and this is set as the reference level.

The operation of the tape tension control device of the present invention will now be described.

While the magnetic tape 2 is running (normal rotation is assumed for the sake of explanation), the take-up reel motor M+ is driven by the take-up drive voltage circuit 29, and the supply reel motor M performs tape tension control. When the load is normal, pin 18. The control power S! Since the voltage level of is higher than the constant voltage SJ, the current generated by the voltage difference between the control power S2 and the constant voltage S3 provides a rotational force that acts as a braking force to the supply side reel motor M. As the load becomes heavier, the control power S! When the voltage level decreases and the constant voltage S becomes a very low level, the current direction is reversed due to the difference voltage between the constant voltage 880 level and the voltage level of the control power St, and the supply side reel motor M is controlled to control the feeding. Become. However, as described above, the supply reel motor M2 is set not to receive voltage that would cause it to rotate independently, so accidents such as unnecessary feeding will not occur.

Although the present embodiment has been explained using a VTR as an example, the present invention is not limited to this, and can be applied to tape winding devices in general that are equipped with motors that independently drive a take-up reel and a supply reel. It is applicable. Further, the positional displacement detecting element, which is a component of the tension detecting means, does not have to be a magnetoresistive element.

〔Effect of the invention〕

The tape tension control device of the present invention includes a magnetic tape tension detection means that detects the tension of a magnetic tape and outputs a detection signal, and is connected to one end of a take-up reel motor or a supply reel motor that is controlled as a sending side. A constant current circuit connected to the other end and voltage converting means provided to allow current to flow into or out of the constant voltage circuit according to the voltage converted from the detection signal. The other end of the side reel motor or the take-up side reel motor has a feature that the potential is (+) or (-) with respect to a constant voltage. Therefore, if the load becomes heavy and the tape tension increases, appropriate control is performed immediately, and accidents such as the magnetic tape being damaged or deviating from the running route can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view illustrating a magnetic tape running path of a magnetic recording/reproducing device, FIG. 2 is a circuit diagram of a conventional tape tension control device, and FIG. 3 is an embodiment of a tape tension control device according to the present invention. FIG. 4 is a plan view schematically illustrating the pickup section provided in FIG. 3. Codes in the figure: 9 is a pickup section, 12 is a magnet, 1
3 is a magnetoresistive element, 17 is a voltage conversion circuit, 18 is a power amplifier circuit, 19 is a constant voltage circuit, 20゜21.22 is an operational amplifier, Q+, Q2, Qg, Q4 are transistors,
MI is a take-up side reel motor, and M2 is a supply side reel motor.

Claims (1)

[Claims] In a tape tension control device that includes two motors that independently drive a take-up reel and a supply reel and controls the tension of a running tape, a tape tension detection means detects the tension of the running tape and outputs a detection signal. and a constant voltage circuit connected to one end of the reel motor controlled as a feed-out side, and a constant voltage circuit connected to the other end of the reel motor, which is connected to the other end, and generates a current to the constant voltage circuit according to the voltage converted from the output signal of the detection means. 1. A tape tension control device comprising: voltage converting means provided for inflow or outflow.