JPH0560180B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a tape speed reference circuit in a tape winding device such as a cassette tape.

[Technical Background of the Invention] When producing video cassettes and audio cassettes, a tape winding device is used that winds a long tape that has been previously wound around a supply reel onto a small-diameter take-up reel. .

Such a tape winding device needs to accurately manage the running speed of the tape in order to prevent the tape from winding irregularly and to wind the tape as fast as possible. A conventional example of a device for managing the running speed of the tape will be explained with reference to FIG.

A supply reel 2 on which a long magnetic tape 1 is wound is attached to the supply reel stand 3 in advance, and the magnetic tape 1 is fed in the direction of the arrow X shown in the figure and is attached to the take-up reel stand 5. Take-up reel 6
It is designed so that it can be wound up. When this magnetic tape 1 is wound onto a take-up reel 6 for a certain length, it is cut by a cutting device (not shown) and subsequently wound onto another new take-up reel.

A drive motor 7 that drives the take-up reel stand 5 is controlled by a tension control circuit 8 to maintain a constant tension when winding the magnetic tape 1.

A tacho roller 9 is disposed along the running path of the magnetic tape 1 and rotates as the magnetic tape 1 slides on the outer periphery of the magnetic tape 1. A large number of small holes 10 are formed in a circular shape coaxially with the tacho roller 9. A perforated disc 11 is attached. A detector 12 placed close to the small hole 10 of the disc 11 outputs a detection pulse signal corresponding to the running state of the magnetic tape 1.

The output of this detector 12 is converted by a speed detection circuit 14 into a voltage proportional to the running speed of the magnetic tape 1, and then sent to a drive circuit 13. Also,
A reference voltage serving as a reference for the running speed of the magnetic tape 1 is inputted to the drive circuit 13 from a reference voltage generating circuit 15. The drive circuit 13 is
The rotation speed of the supply reel motor 16 is controlled so that the reference voltage from the reference voltage generation circuit 15 and the output voltage of the speed detection circuit 14 match, and
The running status of
-Refer to No. 63851).

[Problems with Background Art] The conventional apparatus described above has a problem in that the actual running speed of the magnetic tape 1 is different from the preset running speed. This problem will be explained in further detail with reference to FIG.

This figure is a graph showing changes in the running speed of one roll of the magnetic tape 1 wound on the take-up reel 6, with the vertical axis representing the running speed of the magnetic tape 1 and the horizontal axis representing time t.

Now, the winding end time when one roll of magnetic tape 1 is wound at the set running speed V ₀ is T ₀ ,
The diameter of the magnetic tape 1 wound on the supply reel 2 at this time is assumed to be D ₀ .

When the diameter of the magnetic tape 1 is D ₁ (>D ₀ ),
The running speed V ₁ of the magnetic tape 1 is faster than the set running speed V ₀ as shown by the dashed line in FIG. 5, and as a result, the winding end time T ₁ is
The value is smaller than T ₀ .

On the other hand, when the diameter of the magnetic tape 1 is D ₂ (<D ₀ ), the running speed V ₂ of the magnetic tape 1 at this time is equal to the set running speed V ₀ as shown by the broken line in FIG.
As a result, the winding end time
T ₂ becomes a value larger than the above-mentioned T ₀ .

In this way, if the running speed of the magnetic tape 1 is too fast or too slow than the set running speed V ₀ ,
This is because the gain of the speed control system of the device shown in FIG. 4 is finite.

In order to solve these problems with conventional equipment,
For example, the ratio between the running speed of the magnetic tape 1 and the rotational speed of the supply reel 2 is detected, the diameter of the supply reel 2 is calculated from the result, the output voltage of the speed detection circuit 14 is corrected, and this correction result and the reference voltage are calculated. Generation circuit 15
There is also known a means for controlling the running speed of the magnetic tape 1 by adding the reference voltage (see Utility Model Application No. 59-63851).

However, in this means, the output voltage and the reference voltage generation circuit 15 correspond to the diameter of the supply reel 2.
In order to determine how to add the reference voltage of There were flaws.

[Object of the Invention] The present invention has been made in view of the above circumstances, and it is possible to match the set traveling speed with the actual traveling speed, and to adjust the set traveling speed without making complicated adjustments. It is an object of the present invention to provide a variable tape speed reference circuit.

[Summary of the Invention] The outline of the present invention for achieving the above object is to detect a tape drive system based on a detection pulse signal corresponding to the running speed of the tape wound around a supply reel and taken up by a take-up reel. in the tape speed reference circuit that controls the tape and maintains the tape at a predetermined running speed, a running speed setting means that sends out a set value signal corresponding to the set running speed, and a running speed setting means that counts the detected pulse signal and uses the counting result as the set value. a detection and counting means that sends out a counting end signal when the counting end signal matches the signal; and a detection and counting means that sends out a speed voltage signal that accelerates or decelerates the drive system until the counting end signal is input, and when the counting end signal is input, the setting It is equipped with a speed voltage generation circuit that sends a speed voltage signal corresponding to the running speed to the drive system, and detects the actual running speed of the tape.When the detected running speed matches a preset set running speed, the state is determined. It is characterized by maintaining the

[Embodiments of the Invention] Examples of the present invention will be described below with reference to FIG. In the apparatus shown in the figure, parts having the same functions as those shown in FIG. 4 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

The device shown in FIG. 1 is different from the device shown in FIG. 4 in that the reference voltage generation circuit 15 is omitted and the speed detection circuit 14 is replaced by
A running speed setting means 33 that sends out a set value signal for setting the running speed of the vehicle to a set running speed, a timing circuit 32 that sends out a timing signal b of a constant period, and a timing circuit 32 that sends out a timing signal b of a fixed period, and detects while being reset periodically by the timing signal b. a detection and counting means 30 comprising a count value comparison circuit 31 that counts the detection pulse signal a from the device 12 and sends out a count end signal c when the count value matches the set value signal; and the count end signal c The speed voltage generation circuit 40 sends a predetermined speed voltage signal e to the drive circuit 13 based on the speed voltage signal e. the traveling speed setting means 33;
The detection and counting means 30 and the speed voltage generation circuit 40 constitute a tape speed reference circuit. The counted value comparison circuit 31 includes a first counting circuit 41 which inputs the timing signal b and the detection pulse signal a and counts the detection pulse signal a, as shown in FIG.
It has a comparison circuit 42 which inputs the counting result of the first counting circuit 41 and the set value signal and sends out a counting end signal c when the two values match.

The speed voltage generation circuit 40 receives a counting end signal c
and a control circuit 34 which sends out a control signal based on this input, and a clock signal d which is controlled by this control signal and has a constant period when the magnetic tape 1 starts running.
a second counting circuit 36 that is controlled by the control signal and adds or subtracts the clock signal d and sends out the counted value; D/A conversion circuit 37 that converts the speed voltage signal (analog signal) and sends it to the drive circuit 13 as a speed voltage signal (analog signal) e.
It has

Next, the operation of the device with the above configuration will be explained with reference to a timing chart showing the relationship among the detection pulse signal a, timing signal b, counting end signal c, clock signal d, and speed voltage signal e shown in FIG. .

In FIG. 3, the horizontal axis of each signal indicates time, and this time is divided into three time zones: low speed zone M1, medium speed zone M2, and high speed zone M3. The period of the detection pulse signal a becomes shorter from the low speed zone M1 to the high speed zone M3, which indicates that the running speed of the magnetic tape 1 is gradually increasing.

Further, the timing signal b sent from the timing circuit 32 is a repetitive signal held at a constant period, and has time widths S ₁ -S ₂ , S ₃ -S ₄ , S ₅ - belonging to each of the above-mentioned time zones. S ₆ is the same, and the first counting circuit 41 starts counting at each instant of time S ₁ , S ₃ , and S ₅ and is reset at each instant of time S ₂ , S ₄ , and S ₆ . It's getting old.

Now, when the set value signal from the traveling speed setting means 33 and the counting result of the five detection pulse signals a by the first counting circuit 41 match, the comparison circuit 42
It is assumed that the setting is made in advance so that the counting end signal c is sent from.

In this state, the first counting circuit 41 sends out the counting end signal c when the time _S6 belonging to the high speed zone M3 has elapsed, as shown in FIG. That is,
Detected pulse signal a has the time width S ₅ of timing signal b
- _S6 , the first counting circuit 41 counts five times, and the counting result is input to the comparator circuit 42, so the comparator circuit 42 sends out a count end signal c.

On the other hand, the control circuit 34 of the speed voltage generation circuit 40
Simultaneously with the start of operation of this device, the clock generating circuit 35 is set to the operating state to generate the clock signal d, and the second counting circuit 36 is set to the addition counting state.

As a result, the second counting circuit 36 starts adding and counting the clock signal d, and sequentially sends the addition results to the D/A converter circuit 37. The D/A conversion circuit 37 sequentially D/A converts the addition results of the second counting circuit 36 and sends a speed voltage signal e to the drive circuit 13. The level of this speed voltage signal e increases with the passage of time as shown in FIG. The degree of this increase corresponds to the increase in the running speed of the magnetic tape 1.

Then, when the counting end signal c is input to the control circuit 34 at the instant of time _S6 in the high speed zone M3, the control circuit 34 sends a control signal to the clock generation circuit 35 to stop the generation of the clock signal d. At the same time, a control signal is also sent to the second counting circuit 36 to hold the counting result.

As a result, a constant count result value is sent from the second counting circuit 36 to the D/A converter circuit 37, and the D/A converter circuit 37 outputs a constant speed voltage signal e to the drive circuit 13. Therefore, drive circuit 1
The supply reel motor 16 controlled by the supply reel motor 3 rotates at a constant rotation speed, and as a result, the magnetic tape 1 is maintained at the set running speed set by the running speed setting means 33.

It goes without saying that the present invention is not limited to the embodiments described above, and that various modifications can be made within the scope of the invention.

For example, in the embodiment described above, control of the running speed when the magnetic tape 1 is gradually accelerated has been described. By decreasing the count value of the clock signal d from the clock signal 35 over time, the present invention can also be applied to the case where the running speed of the magnetic tape 1 is gradually reduced.

Furthermore, in order to change the running speed of the magnetic tape 1, it is only necessary to change the set value signal from the running speed setting means 33, change the set value of the count value comparison circuit 31, and change the generation timing of the count end signal c. .

Furthermore, the present invention can also be applied to devices for winding various types of tapes other than magnetic tapes in the same manner as in the above-mentioned embodiments.

[Effects of the Invention] According to the present invention detailed above, even if the gain of the tape speed control system is finite, the tape speed can match the set value of the tape running speed with the actual running speed. A reference circuit can be provided.

Furthermore, it is possible to provide a tape speed reference circuit that allows the set running speed to be easily changed without making particularly complicated adjustments.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing details of the count value comparison circuit in the circuit shown in FIG. 1, and FIG. 3 is a block diagram showing the details of the count value comparison circuit in the circuit shown in FIG. A timing chart showing the relationship; FIG. 4 is a block diagram showing the configuration of a conventional tape winding device and tape speed reference circuit; FIG. 5 shows the relationship between tape running speed and winding time using the device shown in FIG. 4. This is a graph showing. DESCRIPTION OF SYMBOLS 1... Magnetic tape, 2... Supply reel, 6... Take-up reel, 30... Detection and counting means, 33... Running speed setting means, 40... Speed voltage generation circuit.

Claims (1)

[Claims] 1. A tape speed reference circuit that controls the tape drive system based on a detection pulse signal corresponding to the running speed of the tape wound around the supply reel and taken up by the take-up reel, and maintains the tape at a predetermined running speed. a traveling speed setting means for transmitting a set value signal corresponding to the set traveling speed; a detection and counting means for counting the detection pulse signal and transmitting a counting end signal when the counting result matches the set value signal; A speed voltage generator that sends a speed voltage signal that accelerates or decelerates the drive system until the counting end signal is input, and also sends a speed voltage signal corresponding to the set traveling speed to the drive system when the counting end signal is input. A tape speed reference circuit comprising a circuit.