JPH0363955A - tension control device - Google Patents

Abstract

PURPOSE:To always obtain stable tape tension by controlling the tape tension to be kept constant by a driving means by using the output signal of a winding diameter detector and the addition output signal of a variation detector. CONSTITUTION:The position information of a magnet 4 fitted to a tension lever 2 are converted to a voltage by a magnetic sensor 5 and applied to a differential amplifier 8 and the voltage proportional to the change part per unit time of the tape tension is outputted. The signal of a frequency proportional to the tape velocity is detected by a timer roller 12 and a photocoupler 13 and applied as a timer roller FGb to a winding diameter control circuit 11. A reel FGa as the signal of a frequency proportional to the rotating speed of a motor 10 is also applied to the winding diameter control circuit 11. In the winding diameter control circuit 11, according to the ratio of the frequencies between the timer roller FGb and reel FGa, the tape winding diameter is decided and the voltage corresponding to the winding diameter is outputted and added with the output signal of the differential amplifier 8. Then, the driving force of the motor 10 is controlled through a driving circuit 9. Thus, the stable tape tension always is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a tension control device that is used in magnetic recording and reproducing devices and the like and keeps the tension of a tape constant.

BACKGROUND OF THE INVENTION FIG. 2 is a schematic diagram of a tension control device used in a conventional magnetic recording/reproducing device.

Depending on the tension of the tape 1, the tension lever 2 is balanced with the spring 3! Move with. At this time, the magnetic sensor 5 receives the position information of the magnet 4 attached to the tension lever 2.
The voltage is converted into a voltage and applied to an integrating amplifier 7 and a differential amplifier 8. Output of integral amplifier 7 and differential amplifier 8
The outputs of are added together to control the driving force of the motor 10 via the driving circuit 9. The above series of operations keeps the tape tension constant. The integral amplifier 7 amplifies the DC variation of the magnetic sensor 5 so that the tape tension does not change depending on the diameter of the tape wound on the tape 6. Further, the differential amplifier 8 amplifies the alternating current variation of the magnetic sensor 6 to prevent the tape tension from changing when changing the tape speed, running direction, etc.

Problems to be Solved by the Invention However, since this type of tension control device has an integral amplifier, the characteristics of the magnetic sensor 6 may change over time, or if the temperature changes, the tape during normal running may change. There was a practical disadvantage in that the tension tended to change significantly.

The present invention solves these conventional problems and provides a tension control device that can always maintain stable tape tension even if the characteristics of the magnetic sensor 5 change over time or change due to temperature. This is what we provide.

Means for Solving the Problems The present invention provides a winding diameter detecting device for detecting the winding diameter of a tape wound on a reel, a change amount detecting device for detecting a change in tape tension, the winding diameter detecting device and the change. It is characterized by comprising a driving means for controlling the rotational driving force of -1V based on the addition output of the amount detecting device, and controlling the tension of the tape wound on the reel to be kept constant. be.

Function As described above, the tension control device of the present invention detects the tape winding diameter and the change in tape tension, respectively, and controls the tape tension to be kept constant based on the added output. .

EXAMPLE Hereinafter, a tension control device according to an example of the present invention will be explained with reference to the drawings.

FIG. 1 shows a schematic diagram of a tension control device according to an embodiment of the present invention. In Figure 1b, 1 is a tape, 2 is a tension lever, 3 is a spring, 4 is a magnet, 6 is a magnetic sensor, 6 is a beam 1μ, 8 is a differential amplifier, 9 is a drive circuit, 1
o is a motor, 11 is a winding diameter control circuit, 12 is a timer roller, 13 is a photocoupler, a is a beam FG, and b is a timer roller 12.

The operation of the tension control device configured as described above will be explained below.

Depending on the tension of the tape e1, the tension lever 2 is moved by the spring 3.
Move to the equilibrium point with At this time, the positional information of the magnet 4 attached to the tension lever 2 is converted into voltage by the magnetic sensor 5 and applied to the differential amplifier 8.

The differential amplifier 8 outputs a voltage proportional to the change in tape tension per unit time.

Timer roller 12. The photocoupler 13 detects a signal with a frequency proportional to the tape speed and activates the timer roller FGb.
It is added to the winding diameter control circuit 11 as a winding diameter control circuit 11. Also, motor 1
Reel F, which is a signal with a frequency proportional to the rotational speed of o
G a is also added to the winding diameter control circuit 11 . In the winding diameter control circuit 11, the timer roller FGb and ') -17F Ga
The tape winding diameter is determined by the ratio of the frequencies, and a voltage corresponding to the winding diameter is output.

This is added to the output signal of the differential amplifier 8, and the drive circuit 9
The driving force of the motor 10 is controlled through. The differential amplifier 8 is used to amplify the alternating current change of the magnetic sensor 5 and to prevent the tape tension from changing when changing the tape speed, running direction, etc. The winding diameter control circuit 11 prevents the tape tension from changing depending on the winding diameter of the tape. The above configuration ensures that a stable tape tension is maintained at all times.

Effects of the Invention As described above, the tension control device of the present invention includes a winding diameter detecting device for detecting a tape winding diameter in a cassette, a change amount detecting device for detecting a change in tape tension, and a winding diameter detecting device for detecting a change in tape tension. Using the output signal and the added output signal of the change amount detection device,
The tape tension is controlled to be kept constant by the driving means. Therefore, even if the characteristics of the magnetic sensor in the tension detection section change over time or with temperature, a stable tape tension can always be obtained, which is extremely advantageous in practice.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a tension control device according to an embodiment of the present invention, and FIG. 2 is a schematic diagram of a conventional tension control device. 1... Tape, 2... Tension lever, 3... Spring, 4... Magnet, 6...
...magnetic sensor, 6...leaf, 7.
... Integral amplifier, 8 ... Differential amplifier, 9
... Drive circuit, 10 ... Motor, 11
...°... Winding diameter control circuit, 12. Old timer roller, 13... Photo coupler, a... Lee zI/FG, b... Timer roller. 120

Claims (1)

[Claims] a winding diameter detection device that detects a tape winding diameter wound on a reel; a change amount detection device that detects a change in tape tension;
and a driving means for controlling the rotational driving force of the reel based on the summed outputs of the winding diameter detecting device and the change amount detecting device, and controlling the tension of the tape wound on the reel to be kept constant. Tension control device.