JPH028383B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tape winding device.

In magnetic tape winding devices such as tape recorders, so-called reel-to-reel direct tape winding devices do not use a capstan and run the tape by directly driving the reel. The driving motor (hereinafter referred to as the reel motor) is subjected to servo or speed control. FIG. 1 is a schematic diagram of a conventional tape winding device, in which 1 is a magnetic tape, 2 is a supply reel,
3 is a take-up reel; 4 is a tape speed detection roller with an extremely small inertia force that rotates in response to the running force of the magnetic tape 1; 5 is a tape speed detection roller attached to the rotating shaft of the tape speed detection roller 4 and spaced at equal intervals on its circumference; A rotary encoder is provided with notches or shading, 6 is a photo interrupter for obtaining pulse signals from the rotating rotary encoder 5, and 7 is a reel motor for driving the take-up reel 3. In FIG. 1, a magnetic tape 1 (hereinafter simply referred to as tape) is
The tape travels in the direction of the arrow, travels from the supply reel 2 to a head device (not shown), passes through the tape speed detection roller 4, and is wound onto the take-up reel 3. At this time, the running speed of the tape 1 is determined by the rotation of a rotary encoder attached to a tape speed detection roller 4 whose rotational speed changes in proportion to the speed of the tape 1.
It is detected as the frequency of the pulse signal obtained from. The pulse signal passes through the waveform shaping circuit 10 and is given to the speed control circuit 11 as a speed detection signal, and the error signal is used as the motor drive circuit 12.
is controlled to drive the reel motor 7 to keep the tape speed constant.

However, in this conventional method, in order to increase the tape speed during the transition period until the tape speed reaches a predetermined speed, especially during acceleration, regardless of the size of the winding diameter R of the tape 1 wound on the take-up reel 3,
Output from the speed control circuit 11 and sent to the motor drive circuit 1
The speed error signal, which is a DC voltage input to 2, is
Because the reel motor 7 swings throughout its operating range, it generates the maximum torque determined by the motor drive circuit 12. Also, even when some disturbance occurs during steady running and the tape speed momentarily decreases,
A similar situation occurs because the speed control circuit 11 attempts to keep the tape speed constant. This maximum torque is set to a value that allows the tape speed to rise quickly even when the tape winding diameter R of the take-up reel 3 is large, for example near the maximum diameter.

Therefore, even when the tape winding diameter R is small, such as at the beginning of winding the tape 1, as mentioned above, this maximum torque is generated in the reel motor 7, which causes abnormal tension to be applied to the tape 1, causing tape damage. . (Tape tension Te is Te=
τ/Rτ: determined by motor torque). As a countermeasure to this problem, a method of lowering the maximum torque value may be considered, but with this method, as the winding diameter R becomes larger, the tape speed rise time becomes slower, and depending on the environmental conditions, it may not be possible to start up the tape speed. Moreover, as the difference between the maximum values of the tape winding diameters R becomes larger, this measure becomes impossible, and there is a drawback that abnormal tension cannot be avoided when the winding diameter R is small.

The present invention eliminates these drawbacks and provides a tape winding device that does not apply abnormal tension to the tape regardless of the size of the tape winding diameter.

An embodiment of the present invention will be described below with reference to FIGS. 2 and 3.

FIG. 2 is a schematic diagram of a tape winding device according to an embodiment of the present invention. 8 is reel motor 7
9 is a rotary encoder similar to rotary encoder 5, and 9 is a rotary encoder 8.
This photo interrupter is similar to the photo interrupter 6 for obtaining a pulse signal by rotation of the photo interrupter 6.

In FIG. 2, the tape speed is detected by a photointerrupter 6 as in FIG. 1, and the detection signal is input to a speed control circuit 11 via a waveform shaping circuit 10. The speed control circuit 11 internally generates a speed error signal in the form of a DC voltage using the speed reference signal and the speed detection signal, and inputs the speed error signal to the torque limiting circuit 15 .

The torque limiting circuit 15 determines the maximum torque of the reel motor 7 that can be generated by the motor drive circuit 12 based on the information from the winding diameter detection circuit 14 even if the error signal swings throughout the operating range. It is changed according to the size of the tape winding diameter R of the take-up reel 3, and the maximum torque value is controlled to increase as the tape winding diameter R becomes larger. The value of this constantly changing maximum torque is determined from the rise time of the tape speed and the tension allowed by the tape 1, that is, the tension that does not cause damage to the tape.

Here, the winding diameter detection circuit 14 in this embodiment will be described. Pulse signals are obtained from the rotary encoder 8 and the photo interrupter 9 in accordance with the rotation of the take-up reel 3. This pulse signal passes through the waveform shaping circuit 13 and is input to the winding diameter detection circuit 14. On the other hand, a pulse signal is obtained from the speed detection roller 4 as the tape 1 runs, and this pulse signal is also input to the winding diameter detection circuit 14 via the waveform shaping circuit 10. The winding diameter detection circuit 14 obtains information on the tape winding diameter R of the take-up reel 3 based on these two signals. Count the number of pulses obtained from step 5 and find the tape winding diameter value R from the following relational expression.

R=n/N×R' N: Number of slits in rotary encoder 5 R': Radius of speed detection roller n: Number of count pulses Figure 3 shows the torque limiting circuit 15 in this embodiment.
It is a circuit diagram showing a specific example, and switches SW1, SW2,...
...SWm is closed sequentially and changed. In other words, even if the error signal, which is a DC voltage, swings throughout the operating range during a transition period when the tape speed changes, the dividing resistance ratio is changed according to the tape winding diameter R, and the voltage is divided into motor drive circuits 12. is input. In this way, since the upper limit value of the error signal is limited, the maximum torque that can be generated by the reel motor 7 is limited by the winding diameter. At the beginning of winding tape 1, switch SW ₁ ,
SW ₂ , . . . SW _n are all in an open state, the upper limit value of the error signal, that is, the maximum torque value of the reel motor 7 is reduced, and as the tape winding diameter R increases, the switches SW ₁ , SW ₂ , . As SW _n gradually closes, its upper limit value, ie, the maximum torque value of the reel motor 7, changes to a larger value. Therefore, it is no longer possible to damage the tape due to abnormal tension during a transition period of the tape speed when the tape winding diameter R is small as in the prior art.

In addition, in this embodiment, the upper limit of the torque that the reel motor 7 can output is changed in stages,
There is no problem in continuously changing this upper limit by using a so-called voltage-controlled amplifier (VCA) that converts the winding diameter value into a DC voltage and changes the amplifier gain depending on the DC voltage.

As described above, according to the present invention, the ever-changing value of the tape winding diameter is detected, and the maximum torque value that the reel motor can produce at any given time is changed in consideration of the allowable value of the tape tension and the rise time. Therefore, even during the transition period when the tape speed reaches a certain speed or due to disturbances that reduce the tape speed,
Abnormal tension is not applied to the tape, preventing tape damage, and the rise time to the specified tape speed can be made almost constant regardless of the tape winding diameter, ensuring stable tape running at all times. can be realized.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a reel drive system of a conventional reel-driven tape winding device, FIG. 2 is a schematic configuration diagram of main parts of a tape winding device according to an embodiment of the present invention, and FIG. 3 is a diagram of the same device. FIG. 3 is a circuit diagram showing a specific example of the torque limiting circuit of FIG. 1...magnetic tape, 2...supply reel, 3...
Take-up reel, 4...Speed detection roller, 5, 8...
...Rotary encoder, 6,9...Photo interrupter, 7...Reel mork.

Claims (1)

[Claims] 1. A reel motor that rotates a tape take-up reel, a winding diameter detection means that detects the winding diameter of the tape wound on the take-up reel, and a tape that is wound from the supply reel onto the take-up reel by the reel motor. a tape winding device having a tape speed control means for controlling a tape speed of the tape winding device, wherein the upper limit value of the reel motor torque, which changes according to the output of the tape speed control means, corresponds to the output of the reel diameter detection means. A tape winding device characterized in that it has a reel motor torque limiting means that changes the upper limit value continuously or stepwise and increases the upper limit value as the winding diameter of the tape wound on the take-up reel increases. Device.