JPH05298778A - Tape loosening detection apparatus - Google Patents

Abstract

PURPOSE:To provide a tape loosening detection apparatus which quickly and reliably detects loosening of tape utilizing capastan and reel velocity detecting pulse even if tape supply speed is lower. CONSTITUTION:The CPU 81 of a controller 8 compares, within the period where two reel velocity detection pulses 200 corresponding to the rotating velocity of reel 3 are generated, the number of capstan velocity detection pulses 100 corresponding to the rotating velocity of capstan 1 with a specified number preset in the ROM 82. In the case of detecting the loosening of tape 2 on the basis of such comparison, control is effectuated so that the capstan motor 6 and reel motor 7 are stopped through a capstan motor circuit and reel motor drive circuit 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus, and more particularly to a tape slack detecting device for detecting tape slack.

[0002]

2. Description of the Related Art FIG. 5 is a diagram showing a conventional example of a tape slack detecting device mounted on a magnetic recording / reproducing device. The tape 2 transported by the capstan 1 is wound by the reel 3. At this time, a capstan speed detection pulse 100 corresponding to the rotation speed of the capstan motor 6 that rotates the capstan 1 is generated from the FG pulse generator 4, and the reel motor 7 that rotates the reel 3 is also generated.
A reel speed detection pulse 200 corresponding to the rotation speed of the reel pulse generator 5 is generated from the reel pulse generator 5.
0 and 200 are input to the controller 8. In such a tape traveling system, for example, when the reel motor 7 does not rotate or the capstan motor 6 runs out of control, the tape 2 sent by the capstan 1 may not be able to be wound on the reel 3. Occurs. For this reason, the tape 2 is loosened as shown by the dotted line in FIG. 5A, and if left unattended, the tape 2 will wind around the pinch roller 9, resulting in irrecoverable tape damage. Therefore, the pulse 200 from the reel pulse generator 5 is input to the controller 8 including a control circuit or a microcomputer, and if the reel speed detection pulse 200 does not come within a predetermined time, the reel 7 stops. If it is, the control is performed to stop the operation. Alternatively, as shown in FIG. 6, a method of directly detecting the slack of the tape 2 is employed by using a detection unit that is generally called a slack sensor and that specially detects the slack of the tape. An example is shown in FIG. 6, in which a light emitting body 10 such as a light emitting diode is placed at one end, and a phototransistor 11 for detecting the light of the light emitting body 10 is arranged at a position facing the light emitting body 10. There is. When the tape 2 comes loose, the tape 2 enters the point B indicated by the dotted line, so that the light emitted from the light emitting diode 10 is blocked by the tape 2 and cannot reach the phototransistor 11, so that the tape 2 becomes loose. Is detected.

[0003]

In the method of counting the reel speed detection pulse as described above when detecting the slack of the tape in the conventional magnetic recording / reproducing apparatus as described above, particularly the intermittent reproduction or the slow reproduction. If the tape advances slowly like in the mode, the interval of generation of the reel speed detection pulse becomes very long. Therefore, the reel pulse generation interval setting time for detecting the slack of the tape must be lengthened correspondingly, and therefore, when the capstan motor runs out, the tape is driven by the above method. There is a drawback that the slack cannot be detected. Moreover, the generation interval time of the reel speed detection pulse set to detect the occurrence of slack of the tape must be set for each mode according to the tape feed speed. There was a drawback that it put a considerable load on the computer program. On the other hand, when the method of installing the slack sensor to detect the slack of the tape is adopted, it is possible to avoid the above drawbacks, but since a sensor dedicated to the tape slack detection is required, the cost of the device is reduced. There was a drawback that the cost would be high.

Therefore, the present invention eliminates the above-mentioned drawbacks by using a speed detection pulse of a capstan or reel,
An object of the present invention is to provide a tape slack detecting device capable of detecting tape slack quickly and reliably even when the tape is fed slowly.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a tape slack detecting device for detecting slack of a tape in a device having a tape running system in which a reel rotates and winds a tape sent by rotation of a capstan. A capstan speed detection means for generating a first speed detection pulse corresponding to the rotation speed of the capstan, a reel speed detection means for generating a second speed detection pulse corresponding to the rotation speed of the reel, and the reel speed. Comparison means for comparing the number of the first speed detection pulses input from the capstan speed detection means with a prescribed number in a period in which the second speed detection pulse input from the detection means is generated n times, and this comparison And a judging means for judging whether the running of the tape is normal or abnormal based on the comparison result by the means.

[0006]

In the tape slack detecting device of the present invention, the capstan speed detecting means generates the first speed detecting pulse corresponding to the rotational speed of the capstan. The reel speed detection means generates a second speed detection pulse corresponding to the rotation speed of the reel. The comparing means, during the period in which the second speed detection pulse input from the reel speed detecting means is generated n times,
The number of first speed detection pulses input from the capstan speed detection means is compared with a prescribed number. The determining means determines whether the running of the tape is normal or abnormal based on the comparison result by the comparing means.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a tape slack detecting device of the present invention. 1 is a capstan for running a tape sandwiched between a pinch roller 9 in a predetermined pattern, 2 is a tape on which image information is recorded by a video head on a cylinder (not shown), and 3 is a reel for winding the tape 2 4 is an FG pulse generator that generates a capstan speed detection pulse 100 corresponding to the rotation speed of the capstan motor 6, and 5 is a reel pulse generator that generates a reel speed detection pulse 200 corresponding to the rotation speed of the reel motor 7. , 6 is a capstan motor for rotating the capstan 1, 7 is a reel motor for rotating the reel 3, 8 is a capstan motor 6 for detecting looseness of the tape.
And a controller for controlling the reel motor 7 to stop, a pinch roller 9 for pressing the tape 2 against the capstan 1 side to stably run the tape 2, and a reference numeral 10 for starting / stopping the capstan motor 6 and rotating it in a predetermined pattern. A capstan motor servo circuit for controlling and a reel motor drive circuit for driving / stopping the reel motor 7. Further, the controller 8 determines the CPU 81 for determining an abnormality including slack of the tape 2, a program for operating the CPU 81, and the normal number of the capstan speed detection pulse 100 generated between two reel speed detection pulses 200 ( ROM 82 that stores a specified number), a counter 83 that counts the number of capstan speed detection pulses 100 generated from the FG pulse generator 4, and a reel speed detection pulse 20 that is generated from the reel pulse generator 5.
Counter 84 and CPU 81 for counting the number of occurrences of 0
The tape slack detecting device comprises an FG pulse generator 4, a reel pulse generator 5 and a controller 8.

Next, the operation of this embodiment will be described. Since the tape 2 is pressed against the capstan 1 side by the pinch roller 9, when the capstan 1 is rotated by the capstan motor 6, the tape 2 is sent to the reel 3 side. At this time, the reel motor 7 drives the reel 3
Rotates, the fed tape is wound on the reel 3. In the case of normal operation, the tape 2 is wound around the reel 3 while holding a predetermined tension. The FG pulse generator 4 generates a capstan speed detection pulse 100 corresponding to the rotation speed of the capstan motor 6, and outputs this to the counter 83 of the controller 8. Therefore, the counter 83 receives the input capstan velocity detection pulse 1
The number of occurrences of 00 is counted, and the count value is calculated by the CPU 8
Output to 1. The reel pulse generator 5 is a reel motor 7
The reel speed detection pulse 200 corresponding to the rotation speed is generated and output to the counter 84 of the controller 8. Therefore, the counter 84 counts the number of input reel speed detection pulses 200 and outputs the count value to the CPU 81.

The CPU 81 uses the reel speed detection pulse 200
Capstan speed detection pulse 1 while 2 are counted
The number of inputs of 00 (same as the number of occurrences) is detected, and the number of inputs of the capstan speed detection pulse 100 is compared with the number of occurrences (specified number) set in the ROM 82. As a result,
When the number of the capstan speed detection pulses 100 input while the reel speed detection pulse 200 has generated two pulses is larger than the specified number, the CPU 81 has caused the runaway of the capstan motor 6 or the reel 3 to stop. It is determined that the tape 2 has become slack as shown in FIG. 1B, and a command to stop the capstan motor 6 and the reel motor 7 is issued to the capstan motor servo circuit and the reel motor drive circuit 10 via the interface 85. Give out. As a result, the capstan motor servo circuit and the reel motor drive circuit 10 stop the rotation of the capstan motor 6 and the reel motor 7. Further, when the number of the capstan speed detection pulses 100 input while the reel speed detection pulse 200 is generated by two pulses is smaller than the specified number, the CPU 81 determines that the tape 2 is cut, and the interface 81 is used. And issues a motor stop command to the capstan motor servo circuit and the reel motor drive circuit 10. As a result, the capstan motor servo circuit and the reel motor drive circuit 10 stop the rotation of the capstan motor 6 and the reel motor 7.

Next, the principle of the above-mentioned CPU 81 for judging abnormality of tape running will be described. The number of rotations of both the capstan 1 and the reel 3 has a fixed relationship for each winding position of the tape around the reel 3. For example, if the frequency of the capstan speed detection pulse 100 corresponding to the rotation speed of the capstan 1 is a and the frequency of the reel speed detection pulse 200 corresponding to the rotation speed of the reel is b, then a / b = c is the tape 2 Is a constant depending on the winding position of the reel 3 around the reel 3. FIG. 2 shows the number of capstan speed detection pulses 100 indicating the amount of tape movement and the rotation speed of the capstan 1 during intermittent feeding, and the number of reel speed detection pulses 200 corresponding to the reel rotation speed. Shows the relationship. Here, the value of c is often set to about 500 to 2000. Therefore, when the value of c is set to this level, a pulse generation relationship as shown in FIG. 2 occurs between the two. ..

However, for example, when an abnormality occurs in the capstan motor 6, the above-mentioned pulse generation relationship between the two is broken. That is, when the capstan motor 6 runs away, the above-mentioned c becomes large because the frequency of the capstan speed detection pulse 100 becomes high as shown in FIG. 3, and at this time, if the rotation of the reel 3 is stopped, c becomes infinite. Become big. On the other hand, when the tape is broken, the frequency of the reel speed detection pulse 200 becomes high as shown in FIG. 4, so that the above-mentioned c becomes a small value. As a method of actually determining such an abnormality of c, when the capstan speed detection pulse 100 is generated a certain number of times but the reel speed detection pulse 200 is not generated, the capstan motor 6 runs away. Alternatively, it can be determined that the reel 3 has stopped. Conversely, the reel speed detection pulse 200
Even though a certain number of times occurred, the capstan speed detection pulse 1
When the number of occurrences of 00 is less than the specified number, it can be determined that the tape is broken. Therefore, the capstan speed detection pulse 100
By comparing the number of occurrences (frequency) of the reel speed detection pulse 200 with the number of occurrences (frequency) of the reel speed detection pulse 200, the tape 2
It will be possible to judge whether or not there is slack. Specifically, while the reel speed detection pulse is generated in the memory (ROM 82) or the like by about two pulses, the number of capstan speed detection pulses 100 that should be generated during this period if normal is set. CPU8 judgment
1 can be done. In addition, the value of c is for reel 3
Although it depends on the winding position of the tape, the value of c becomes the maximum value of c, that is, the value of c when the winding diameter of the reel 3 becomes the minimum at the beginning of winding the tape 2 at all winding positions. Even if it is applied, there is no practical problem. Therefore, in the ROM 82 shown in FIG. 1, the number of generated capstan speed detection pulses 100 is set as a predetermined number while two reel speed detection pulses 200 are generated.

According to the present embodiment, the number of capstan speed detection pulses 100 corresponding to the rotation speed of the capstan 1 is generated while two reel speed detection pulses 200 corresponding to the rotation speed of the reel 3 are generated. Even when the tape 2 is fed slowly, such as in the intermittent playback mode or slow playback mode, the reel speed detection pulse 200 is compared with the preset number in the ROM 82 by the coat roller 8 and the looseness of the tape 2 is detected based on the comparison result. 2 is generated for a short time, it is possible to quickly detect the slack of the tape 2 and stop the capstan motor 6 and the reel motor 7 in any case. Moreover, the existing capstan speed detection pulse 100 is provided without providing a special sensor or the like for detecting the slack of the tape.
Since the reel speed detection pulse 200 is used, the above effect can be obtained without increasing the cost of the apparatus.

[0013]

As described above, according to the tape slack detecting device of the present invention, the slack of the tape can be swiftly and surely secured by using the speed detection pulse of the capstan or the reel even when the tape feeding is slow. Can be detected.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a tape running system of a magnetic recording / reproducing apparatus equipped with a tape slack detecting device of the present invention.

FIG. 2 is a diagram showing a relationship between a capstan speed detection pulse and a reel speed detection pulse.

FIG. 3 is a diagram showing another relationship between a capstan speed detection pulse and a reel speed detection pulse.

FIG. 4 is a diagram showing still another relationship between a capstan speed detection pulse and a reel speed detection pulse.

FIG. 5 is a diagram showing an example of a tape running system of a magnetic recording / reproducing apparatus equipped with a conventional tape slack detecting device.

FIG. 6 is a diagram showing an example of a tape slack detecting device using a conventional slack sensor.

[Explanation of symbols]

1 ... Capstan 2 ... Tape 3 ... Reel 4 ... FG pulse generator 5 ... Reel pulse generator 6 ... Capstan motor 7 ... Reel motor 8 ... Controller 9 ... Pinch roller

Claims (1)

[Claims] 1. A tape slack detecting device for detecting slack of a tape in an apparatus having a tape traveling system, wherein a reel rotates and winds a tape sent out by the rotation of a capstan, corresponding to a rotation speed of the capstan. A capstan speed detecting means for generating a first speed detecting pulse, a reel speed detecting means for generating a second speed detecting pulse corresponding to the rotation speed of the reel, and a reel speed detecting means for receiving a second speed detecting pulse. Based on the comparison result by the comparing means for comparing the number of the first speed detecting pulses input from the capstan speed detecting means with a prescribed number in a period in which the second speed detecting pulse is generated n times, A tape slack detecting device comprising: a determining unit that determines whether the running of the tape is normal or abnormal.