JPS63275065A - Magnetic tape device - Google Patents

Abstract

PURPOSE:To quickly obtain the necessary tape position by deciding the speed reducing characteristic line conforming to a tape winding state in pair of reels based on the signal obtd. from a tape amt. detection device, and braking a tape traveling at the time when the speed of the tape under traveling is coincided with that on the speed reducing characteristic line. CONSTITUTION:The device is equipped with a pair of reels 1, 2 on which a recording medium tape 5 is wound, the reel motors 3, 4 combined with the reel, the magnetic head 6 converting a signal relating to the tape, tape amt. detection devices 13, 14 for detecting the tape amt. of the reel and a tape traveling amt. detection device 9 for obtaining the output corresponding to the tape traveling amt. The speed reducing characteristic line conforming to the tape winding state in a pair of the reels 1, 2 based on the signal obtd. from the tape amt. detection device is then decided and a pair of reel motors 3, 4 are controlled so as to brake the tape traveling at the time coincident with the speed on the speed reducing characteristic line of the tape under traveling. The necessary tape position is thus obtd. quickly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic tape device that can quickly run a tape to a desired tape position.

[Prior Art] In order to bring the magnetic tape to a desired position facing the magnetic head, the magnetic tape is fed at high speed, and when the magnetic tape is near the desired position, a pair of reel motors are energized in opposite directions. It has already been done to run the tape at a constant low speed to the desired position W1 after reducing the tape speed to a predetermined value without entering the electromagnetic brake state.

[Problems to be Solved by the Invention] By the way, when a large reel such as a No. 14 reel is used, the inertia is large, and the inertia varies depending on the tape winding diameter. Therefore, conventionally, the deceleration point at which the electromagnetic brake is applied has been determined by taking into account the maximum speed of the tape and the maximum braking time.

That is, the deceleration point had to be determined with sufficient margin so that the desired position would not pass the head during high-speed feeding. To explain in more detail, when the tape winding diameter on the take-up reel is small, since the take-up reel is rotating at high speed, the time from the start of deceleration to the predetermined low speed or stop state is long; When the tape winding diameter on the take-up reel is large, the take-up reel is in a low speed rotation state, so the time from the deceleration start point to the predetermined low speed or stop state is short. Because the deceleration time changes in this way, in conventional devices, the deceleration start point is determined according to the maximum deceleration time. Therefore, the desired tape position could not be quickly obtained.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a magnetic tape device that can quickly obtain a desired tape position.

[Means for Solving the Problems] The present invention for solving the above problems and achieving the above objects includes: a pair of reels around which a recording medium tape is wound;
a pair of reel motors coupled to the pair of reels;
a magnetic head for converting signals in relation to the tape; a tape amount detection device for detecting the amount of tape on at least one of the pair of reels; and obtaining an output corresponding to the amount of travel of the tape. a tape running amount detecting device for detecting a tape running amount; and by running the tape and then decelerating it, the tape moves from a first state in which the first position of the tape faces the head to a second position of the tape. When transitioning to the second state facing the head, a deceleration characteristic line matching the tape winding state on the pair of reels is determined based on a signal obtained from the tape amount detection device, and and a circuit for controlling the pair of reel motors so as to apply a brake to the tape running when the tape matches or almost matches the speed on the deceleration characteristic line of the running tape in order to obtain a position. It is.

[Operations] The tape l detection device in the above invention can be comprised of a speed detector such as an optical encoder coupled to a pair of reels or a motor, for example.

The signal obtained from the tape amount detection device or the signal corresponding thereto is used as tape winding diameter (tape amount) information on the reel. If you know the tape winding diameter from this signal,
It is possible to know or predict the deceleration characteristics when applying the brakes. 'fIf the ideal or near-ideal deceleration characteristic in the vicinity of the 4th speed opening time point is determined, it becomes possible to control the pair of reel motors to follow this deceleration characteristic. This allows the desired tape position to be quickly obtained.

[Embodiment] Next, a reel-to-reel magnetic tape device according to an embodiment of the present invention will be described with reference to the drawings. The magnetic tape device shown in FIG. 1 has a pair of No. 14 reels 1.2, to which are coupled a pair of reel motors 3.4. The traveling path of the magnetic tape 5 wound around a pair of reels 1.2 includes a recording/reproducing head 6, a capstan 7, and a pinch roller 8.
, a tape running amount detection roller 9 is arranged.

The left reel motor 3 is connected to the control drive circuit 10 so as to bias it clockwise as shown by the arrow, and the right reel motor 4 is connected to the control drive circuit 10 so as to bias it counterclockwise. ing. By energizing the right reel motor 4, the tape 5 runs in the forward direction from left to right, and by energizing the left reel motor 3, the tape 5 runs in the reverse direction from right to left. Note that when the tape is running, a voltage is applied to the supply reel motor to apply pack tension as necessary. Although not shown, a device for detecting the tension of the tape 5 is provided, and the pair of reel motors 3.4 are controlled so that the tension of the tape 5 is constant.

The capstan 7 is for running the tape 5 at a constant low speed, and a capstan motor 11 is coupled thereto, and this motor 11 is connected to a control drive circuit 10.

The roller 9 is in rolling contact with the tape 9 so that the number of rotations corresponds to the amount of tape travel. A pulse generator 12 consisting of a speed detector in the form of an optical encoder is connected to this roller 9 . The pulse generator 12 includes an optical slit connected to the roller 9, a light emitting element, and a light receiving element that generates a pulse each time the optical slit passes, and generates a number of pulses corresponding to the amount of tape travel. The roller 9 and the pulse generator 12 function as a tape travel amount detection device and a tape speed detection device.

A speed detector 13.14 is coupled to the pair of reel motors 3.4. The speed detectors 13,14 also consist of optical encoders. That is, the speed detectors 13.14 are connected to the reel 1.
It is composed of an optical slit plate that rotates in accordance with the rotation of 2, a light emitting element, and a light receiving element, and is configured so that the light receiving element detects passage of the optical slit and generates a pulse.

The microcomputer 15 is provided to perform various signal processing and control, and the pulse generator 12, speed detectors 13, 14, and control drive circuit 10 are connected here. This microcomputer 15 has a built-in counter that counts the pulses given from the pulse generator 12.

It also has a function of detecting the tape winding diameter based on the speed information given from the speed detectors 13 and 14 and determining the time point at which deceleration starts during a search. The microcomputer 15 includes a line 16 for providing desired tape position information during a search, a line 17 for resetting a tape running amount counter, and a line 18 for inputting various mode setting signals.
is connected. Well, ゛Microcomputer 1
5 and the control drive circuit 10 are provided with fast forward, rewind, play and stop lines 19, 20, 21 and 22.

[Operation] Mode settings such as play, fast forward, and rewind are done exactly the same as with a general tape recorder.When the tape 5 is run,
The pulse generator 12 generates a number of pulses corresponding to the traveling distance at a frequency corresponding to the tape speed. This pulse is counted by a counter within the microcomputer 15. The counter can be reset at any position by applying a reset signal from line 17. Therefore, the amount of tape travel is counted based on the reset position. An arbitrary tape position after running the tape 5 arbitrarily (
When the tape 5 is quickly run to the desired value W (second position) at the first position) and then stopped, the line 1
6 to the desired position (second position). The desired value W (second position) may be a position other than the position where the value of the counter that counts the amount of tape travel is zero, but here, for ease of explanation, we will assume the position where the counter is zero. This will be explained as the stop target position (second position).

(first position of the tape currently facing the head 6)
The tape length between the first position and the second position at which the tape is desired to be stopped can be determined by the value of the counter. Furthermore, when tape running is started, output pulses are obtained from the first and second speed detectors 13.14, so the winding diameter (winding amount) of the tape on the reel 1.2 can be known.

Information on the tape winding diameter on the reel 1.2 is obtained by noting that the number of revolutions of the reel 1.2 changes as the tape winding diameter changes. When traveling in the forward direction, a high rotational speed of the take-up reel 2 means that the winding diameter is small, and a low rotational speed of the winding-side reel 2 means that the winding diameter is large. Also, when traveling in the forward direction, the supply side reel 1
A small rotational speed means that the winding diameter is large, and a large rotational speed means that the winding diameter is small.

Each speed detector 13.14 generates pulses with a period proportional to the rotational speed of each reel 1.2.

Therefore, the repetition frequency of the output pulses of each speed detector 13.14 contains the rolling speed information and the tape winding diameter information of each reel 1.2.

When a command is given to the microcomputer 15 to make the desired position (second position) of the tape 5 face the head 6, the tape 5 enters a high speed running (fast forward) state. This causes the speed detectors 13, 14 to generate speed detection pulses at a frequency that is inversely proportional to the tape winding diameter. The microcomputer 15 counts the speed detection pulses generated per unit time (1 second), and calculates the output frequency F1 of the first speed detector 13 and the output frequency F2 of the second speed detector 14 using the microcomputer 15. The computer 15 performs the following calculation to determine the winding diameter value K.

(F2)/C-(Fl)/C= Here, C does not indicate the frequency of the output of the pulse generator 12.

When Fl = F2, where K is zero, the tape 5 is wound in half on the pair of reels 1.2.

This means that as the winding diameter value K increases in the positive direction, the winding diameter of the take-up reel 2 becomes larger than 50%, and as the winding diameter value K increases in the negative direction, the winding diameter of the take-up reel 2 increases. This means that the winding diameter is small.

The microcomputer 15 stores in advance a large number of deceleration characteristic lines in its memory. The deceleration characteristic lines are characteristic lines such as 20x, 24x, 28x, etc. that do not show a decrease in speed as shown in FIG.

In this example, X indicates the value of a counter that counts the amount of tape travel; the steeper the slope of this characteristic line, the faster the desired deceleration will be completed. The characteristic line 24x shows the characteristic when the tape winding diameter of the take-up reel 2 is 50% (Fl = F2 and = 0), and the characteristic line 20x shows the characteristic when the tape winding diameter of the take-up reel 2 is smaller than 50%. It is clear from this that it shows the characteristics when the tape winding diameter of the take-up reel 2 is larger than 50% (F2 < Fl and = positive value). As shown, the deceleration time changes depending on the change in the tape winding diameter of the take-up reel 2. Therefore, the microcomputer 15 selects a deceleration characteristic line that matches the tape winding diameter value K. Although three characteristic lines are shown in FIG. 2, in reality, there are many more characteristic lines that have the following relationship with the winding diameter value, for example.

K=-4...20x K=-3... 21x K=-2... 22x K=-1... 23x K= O... 24x K=+1...・ 25x K=+2 ・ ・ ・ ・ 26x K=+3 ・ ・ ・ ・ 27x The determination of the deceleration characteristic line is performed every 250 m5ec, for example. As the tape continues to run steadily, the winding diameter changes, so the ideal or near-ideal deceleration characteristic line also changes. now,
If the winding diameter value K is -4 in the vicinity of the target stop position (second position), the microcomputer 15 follows the characteristic line 2. Select Ox.

Then, the intersection point A1 between the high-speed tape speed (for example, v5=speed corresponding to the frequency 500H2 of the speed detection pulse) and the characteristic line 20x is determined. That is, the point where the tape running speed is higher than the speed on the line of the selected characteristic 11120x is determined.

When point A1 is detected, the microcomputer 15 generates a deceleration command, and if it has been outputting a fast forward mode signal until now, it outputs a rewind mode signal. As a result, the pair of reel motors 3.4 are energized in opposite directions (rewind mode), the electromagnetic brake is activated, and the tape speed decreases along the deceleration characteristic line 20x. A low speed (for example, 100 am) stored in the microcomputer 15
/SeC) and the tape speed detected based on the output of the pulse generator 12 are compared in the microcomputer 15, and at the time t1 when both match, the electromagnetic brake control (rewind control) is released and the playback is started. A mode signal is generated and the tape 5 moves at a low constant speed (7 Eica
/5f3C) until the target position tPo.

When the target position WIPo is reached, the counter value also becomes 1G (zero), and the microcomputer 15 generates a stop signal.

When characteristic 1128x in Fig. 2 is selected because the tape winding diameter of the take-up reel 2 is large near the start of deceleration, the high feed speed (F5 = 50OH2 equivalent speed)
The intersection with the equivalence line 28x is determined as the deceleration start point A2, and the deceleration mode using the electromagnetic brake starts from the counter value t2 (position P2).

The deceleration start point A2 is later than A1 by t4-t2,
Because the tape winding diameter of the take-up reel 2 is large, a large braking effect can be obtained, and the time it takes to reach the deceleration target speed ■1 is short. Therefore, the time width from t1 to t10 is independent of changes in the tape winding diameter. becomes constant. If the deceleration control is started at A1, which is the same as in the case of the deceleration characteristic line 20x, even though the tape winding diameter of the take-up reel 2 is large, the characteristic line as shown by the chain line 23 in FIG. and lower speed (76w
/5eC), which increases the running time and makes quick searches impossible.

Even when the tape 5 is run to a predetermined position and stopped in the rewind mode, it operates on the same principle as in the fast forward mode. However, in this case, the winding diameter value K is determined by the following formula.

(Fl)/C-(F2)/C=K [Modifications] The present invention is not limited to the above-described embodiments, and, for example, the following modifications are possible.

(1) Instead of the microcomputer 15 in FIG.
An lltllll circuit shown in FIG. 3 may be provided.

In FIG. 3, an up/down counter 31 is provided which counts the output of the pulse generator 12, which is the same as in FIG. This counter 31 is reset by a reset signal and outputs a value compared with the amount of tape travel from the reset position. Note that when driving in the forward direction, the count is up, and when driving in the reverse direction, the count is down. The output of the counter 31 is sent to an arithmetic circuit 32 and a first comparator 33. The tape winding diameter signal forming circuit 34 is the same speed detector 13 as shown in FIG.
．． Based on the signal from 14, a signal indicating the tape winding diameter of reel 1.2 is given to arithmetic circuit 32.

In the calculation circuit 832, a signal indicating the stop target position is sent to the line 35.
is input. When the arithmetic circuit 32 is given the stop target position, it calculates the difference □ (tape length) between the current position and the stop target position based on the output of the counter 31 indicating the current tape position and the signal indicating the tape running stop target position. Find 0
, based on the signal indicating the current winding diameter of reel 1.2 and the tape length at the target stop position Wt, the target stop position f is determined.
! ! Calculate the winding diameter of glue 1.2 when the tape is run up to Then, the optimum deceleration characteristic line at the target stop position is selected from the memory 36, and the counter value of the deceleration start point is set. The deceleration start counter value obtained from the arithmetic circuit 32 is input to the first comparator 33 and compared with the actual counter output given from the counter 31, and when they match, a deceleration command signal is generated.

□Execution of deceleration by the deceleration command signal is the same as in FIG.

The output of the pulse generator 12 is converted into a speed voltage by a frequency-voltage converter 37, and this and a voltage indicating the deceleration end point speed (100 am/5ec) given from a reference voltage circuit 38 are converted by a second comparator 39. be compared.

When the speed voltage becomes equal to the reference voltage, the deceleration control by the electromagnetic brake ends, and the tape is fed to the target position at a constant speed.

(2) Instead of detecting the tape winding diameter on the reel 1.2 using the speed detector 13.14, the tape winding diameter may be detected directly optically or magnetically.

(3) The speed detectors 13 and 14 and the pulse generator 12 may be configured as magnetic speed detectors using magnetoelectric conversion elements or the like.

(4) It is also applicable to the case where the tape is stopped without providing a constant speed mode from tl to to.

[Effects of the Invention] As is clear from the above, according to the present invention, a desired tape position can be quickly obtained in various tape winding diameter states.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a magnetic tape device according to an embodiment of the present invention, Fig. 2 is a characteristic diagram showing a deceleration characteristic line, and Fig. 31! 1 is a block diagram showing a control circuit of a modified example. 1.2... Reel, 3.4... Reel motor, 5... Tape, 6... Head, 12... Pulse generator, 13.14... Speed detector, 15...・Microcomputer.

Claims (1)

[Scope of Claims] [1] A pair of reels around which a recording medium tape is wound, a pair of reel motors coupled to the pair of reels, and a magnetic head that exchanges signals in relation to the tape. , a tape amount detection device for detecting the tape amount of at least one of the pair of reels; a tape running amount detection device for obtaining an output corresponding to the running amount of the tape; and then decelerate, thereby transitioning from a first state in which the first position of the tape faces the head to a second state in which a second position of the tape faces the head. In this case, a deceleration characteristic line suitable for the tape winding state on the pair of reels is determined based on the signal obtained from the tape amount detection device, and the speed of the running tape is reduced in order to obtain the second position. and a circuit for controlling the pair of reel motors so as to apply a brake to tape running when the speed matches or almost matches the speed on the deceleration characteristic line.