JP2502966B2 - Tape transfer device - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a tape transfer device for transferring a tape from reel to reel.

[Conventional technology]

Conventionally, as one configuration of a magnetic storage device, there is one in which a supply reel and a take-up reel are driven by separate motors, respectively, and a magnetic tape wound around these reels is transferred to a head portion. An example of this apparatus is disclosed in Japanese Patent Laid-Open No. 52-6200.
It is described in Japanese Patent No. 4 publication.

[Problems to be Solved by the Invention]

The reel-to-reel type tape transfer device in this type of magnetic storage device is provided with a derivation means for calculating reel inertial load in order to control the movement of the tape. However, no consideration was given to the correction of the tape acceleration caused by the error in deriving the reel inertial load or the constant error of the device parts.

Therefore, in the tape transfer device, when the tape is started up to a predetermined speed with high acceleration, the time required to reach the predetermined speed, in other words, the access time is changed. Even if the drive current that supplies the same acceleration of the tape to the respective motors for driving the two reels is supplied to the respective reels, the weight of the tapes, the shape of the tapes, the variations in the shape of the motors, and the fluctuations in the access time. This is caused by a difference in the tape acceleration at the reel outlets because the motor load due to the manufacturing error such as the torque constant is different.

Since the tape transfer device targeted by the present invention forms a two-mass vibration system in which reel systems driven by respective motors are connected via an elastic body called a tape,
When driving from a stationary state, tape tension fluctuations occur unless the tape accelerations of both reel systems are almost the same. That is, the tape expands and contracts. The tape vibrates as the tape expands and contracts.

Particularly when accelerated at a high speed, the tape acceleration error of the two reel system increases due to the increase of the absolute value of the acceleration, and the vibration, that is, the fluctuation of the tension increases.

The present invention has been made in view of the above situation,
Even when the constants of the parts that make up the device change, the change in access time can be reduced, and high-speed access tape running that does not cause large tension changes can be performed. An object of the present invention is to provide a tape transfer device that can perform recording or reproduction accurately.

[Means for solving the problem]

The present invention relates to a reel-to-reel type tape transfer device in which, when a tape is started at high speed, due to variations in mechanical parts such as a motor and electric circuit parts such as a power amplifier, acceleration time (up to a switching speed Vc) We focused on the fact that the tape tension changes due to the change in the switching time tc).

In the tape transfer device that has two reel driving means and transfers the tape from one reel to the other reel, the time detection means detects the time until the speed of the tape reaches a predetermined speed at the time of starting the tape. And an acceleration error deriving means for calculating an actual acceleration from the detection time and deriving an acceleration error from a preset reference tape acceleration, and a reel driving means for reducing the acceleration error by the output of the acceleration error deriving means. Means for generating a signal for correcting the signal for driving the motor provided,
This is achieved by including a correction signal storage means for storing this correction signal, and a control means for driving the motor provided in the reel drive means by the drive signal corrected by the stored correction signal at the next tape startup. .

[Action]

When the tape is recorded or played back, the time (switching time tc) until the tape reaches the predetermined tape speed (switching speed Vc) is measured, and the acceleration error is calculated using the relationship between the switching time and the tape acceleration that was obtained in advance. To detect. Next, the currents of the two motors are corrected in a direction to reduce the detected acceleration error so as to eliminate the fluctuation of the tape acceleration time, and the correction values of the motor currents are stored, and the tape acceleration for the next time and thereafter is accelerated. Sometimes used and can be corrected.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram showing an embodiment of a tape transfer device according to the present invention, in which 1 is a magnetic tape, 2 and 3 are reels around which the magnetic tape 1 is wound, and these reels 2 and 3 are motors 4 respectively. , 5 driven by. The magnetic tape 1 is driven by the motors 4 and 5 from one reel 3 to the tension sensor 6,
It is transferred to the other reel 2 via the magnetic head 7 and the speed tachometer 8.

At this time, the magnetic head 7 records a data signal on the magnetic tape 1 or reproduces a signal from the magnetic tape 1.

Here, since the magnetic tape 1 is an elastic body made of polyester film or the like and having low rigidity, a plurality of vibrations are caused by the moment of inertia of the reels 2, 3, the speed tachometer 8, the tension sensor 6 and the spring property of the magnetic tape 1. Mode occurs. These vibration modes are likely to occur when the magnetic tape 1 is accelerated at maximum acceleration. The control circuit 9 controls the movement of the magnetic tape 1 by driving signals S1, to the motors 4 and 5.
S2 is generated, and the power amplifiers 10 and 11 convert the power of these signals S1 and S2 to drive the motors 4 and 5. The control circuit 9 controls the tape speed by correcting the acceleration error.

The tension circuit 12 receives a signal from the tension sensor 6, detects a tape tension error when the tape is running, generates a correction signal for reducing the tension error, and outputs the correction signal to the power amplifier 11. As a result, the tape tension during tape running is controlled via the motor 5 and the reel 3.

FIG. 2 is a block diagram showing details of the control circuit 9. In FIG. 2, the switching circuit 9d is a speed detector.
9b and the output of the arithmetic circuit 9a, while the detected tape speed is smaller than the target speed, the output of the arithmetic circuit 9a (maximum acceleration signal S3) is selected, and after reaching the switching speed, Select the speed error signal of. The arithmetic circuit 9a determines the state of the magnetic tape 1 wound on the reels 2 and 3 (tape radius,
Receiving a signal from a circuit (not shown) for measuring the reel inertia moment), the maximum acceleration signal S3 is output to the switching circuit 9d. In addition, the first correction signal S4, S for the reel load
Output 5 to the adders 9j and 9k.

On the other hand, the speed detector 9b is a circuit for performing speed detection by counting the pulse width of the speed tachometer signal S6 using the clock of the reference clock generator 9c. Switching circuit
The output signal of 9d is multiplied and corrected by the first correction signals S4 and S5 in the multipliers 9e and 9f, and the motor current command values S1 and S2 are output to the power amplifiers 10 and 11. The power amplifiers 10 and 11 supply currents to the motors 4 and 5 according to the motor current command values S1 and S2 to drive the reels 2 and 3. As described above, the control circuit 9 outputs the optimum motor current command value for starting or running the tape.

Here, the acceleration process of the magnetic tape 1 will be described with reference to FIG.

If the tape speed up to the switching speed Vc is smaller than the target speed, a constant acceleration signal (maximum acceleration signal S3) is generated by the switching circuit 9d. This constant acceleration signal is a constant value peculiar to the apparatus, and acceleration by this acceleration is always required. The value of this acceleration is determined as the tape acceleration required to satisfy the access time (the time from when the tape is stopped until the tape speed at which recording and reproduction is possible) as the specifications of the apparatus.

The output signal (constant acceleration signal S3) of the switching circuit 9d is multiplied and corrected by the first correction signals S4 and S5 in the multipliers 9e and 9f, respectively, so that the tape acceleration of each reel motor matches the constant acceleration signal S3. Current commands S1 and S2 are output. Here, the constant acceleration signal S3 has a constant value, and the current command values S1 and S2 also have constant values. As a result, each motor is driven with a constant torque, the rotation speed of each reel motor increases constantly, and the tape speed increases linearly. At this time, the first
The correction signals S4 and S5 are calculated by the arithmetic circuit 9a in accordance with the tape radius in that state, the reel inertia moment, etc., and the constant acceleration signal S3 matches the tape acceleration of each reel motor with the constant acceleration signal S3. Current command for S1, S
Convert to 2.

Next, when the tape speed exceeds the switching speed Vc, this time the switching circuit 9d switches to the speed control mode.
A current proportional to the speed error is supplied to each motor, and the target speed V0 is gradually approached.

When the predetermined torque is not output from each reel due to variations in mechanical parts such as a motor or electric circuit parts such as a power amplifier, an error occurs in each reel acceleration, and the tape acceleration changes. When an acceleration error occurs on the tape, the switching time tc, which is the time required to reach the switching speed Vc, changes from t1 to t2.

Further, due to this influence, the access time from the tape activation to the target speed also changes. Letting b be a speed curve when the tape acceleration is normal, a speed curve a shows a case where the tape acceleration is shifted in the plus direction, and a speed curve c is a case where the tape acceleration is shifted in the minus direction. Thus, the acceleration error generated on the tape can be detected by measuring the switching time.

In FIG. 2, the time counter 9g receives the clock signal of the reference clock generator 9c and the signal of the speed detector 9b,
The time until the speed of the magnetic tape 1 reaches the switching speed Vc (switching time tc) is detected.

Next, the conversion table 9h converts the switching time into tape acceleration based on the relationship obtained in advance and outputs it. The correspondence relationship between the switching time (ti) and the tape acceleration (αi) is as shown in FIG. The correction circuit 9i receives the acceleration signal converted (detected) by the conversion table 9h, calculates and stores the second correction value for eliminating the acceleration error, and outputs it. The output of the correction circuit 9i is added to the first correction signals S4 and S5 by the adders 9j and 9k to add and correct the drive signals of the motors 4 and 5. Here, the correction circuit 9i stores the second correction value obtained from the tape operation error when the tape is started, and is used when the tape is started next time. As a result, each time the tape accelerating operation is repeated, the tape acceleration error is eliminated and the change in the switching time is also eliminated. At the same time, fluctuations in access time are eliminated.

The case of the velocity curve c in FIG. 3 will be described as an example. The speed curve c has a smaller tape acceleration than the normal speed curve b. That is, the tape acceleration is small because the torque generated by each reel motor is smaller than the predetermined torque due to variations in mechanical parts such as a motor or electric circuit parts such as a power amplifier. At this time, the two reels do not always have the same influence due to the variations in the mechanical components and the electric circuit components, and the tension variation occurs due to the difference in the tape acceleration at the two reel outlet portions at the start of tape acceleration.

However, as shown in FIG.
The tension is controlled by the tension circuit 12, and the torque of the reel 3 is compensated by the tension error signal. That is,
It can be seen from the tension error signal generated by the tension fluctuation that the tape acceleration at the reel 3 outlet operates so as to match the tape acceleration at the reel 2 outlet. That is,
The tape will be accelerated while the fluctuation in tension occurring at the start of tape acceleration gradually decreases.

In this case, in order to increase the tape acceleration, the second correction is performed only on the reel 2 to increase the torque of the reel 2, that is, when the output of the correction circuit 9i is added only to S5, the tape acceleration 2 The tape acceleration error at the one reel outlet becomes large and the tension fluctuation becomes large. Therefore, as shown in FIG.
By adding it to one reel, the tape acceleration, that is, the tape switching time, can be adjusted tc without increasing the tension fluctuation. According to this embodiment, it is possible to eliminate the change in the switching time and the access time without increasing the change in the tape tension.

FIG. 5 is a block diagram showing another embodiment of the device of the present invention. In this example, the speed tachometer 8 is configured to measure the outermost peripheral speed of the reel. With such a configuration, the tape speed of the reel 2 can be detected by the speed tachometer 8. Also in this case, the same effect can be obtained by the same operation as that of the above-described embodiment. That is, the present invention shows that the position of the speed tachometer 8 is not limited to the embodiment shown in FIG.

〔The invention's effect〕

As described above, according to the present invention, in the tape transfer device, the tape acceleration can be corrected, and the access time fluctuation can be reduced without increasing the tape tension fluctuation.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the device of the present invention, and FIG.
FIG. 3 is a block diagram showing the details of the control circuit in the figure, FIGS. 3 and 4 are diagrams for explaining the operation of the device of the present invention, and FIG. 5 is a diagram showing another embodiment of the device of the present invention. 1 ... Magnetic tape, 2, 3 ... Reel, 4,5 ... Motor, 6 ... Tension sensor, 8 ... Speed tachometer, 9 ... Control circuit, 9a ... Arithmetic circuit, 9b ... Speed detector, 9c ... Reference clock generator, 9d ...
Switching circuit, 9e, 9f ... Multiplier, 9g ... Time counter, 9h ... Conversion table, 9i ... Correction circuit, 9j, 9k ... Adder, 10, 11 ... Power amplifier.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-55-25839 (JP, A) JP-A-52-62004 (JP, A) JP-B-59-22300 (JP, B2)

Claims (1)

(57) [Claims] 1. A tape transfer device comprising two reel drive means for transferring a tape from one reel to another reel, wherein time detection is performed to detect a time until a tape speed reaches a predetermined speed at the time of starting the tape. Means, an acceleration error deriving means for calculating an actual acceleration from the detection time and deriving an acceleration error from a preset reference tape acceleration, and a reel driving means for reducing the acceleration error by the output of the acceleration error deriving means. A means for generating a signal for compensating the signal for driving the motor provided in, and a correction signal storage means for storing the correction signal are provided, and the drive signal corrected by the stored correction signal at the next tape start-up. A tape transfer device comprising: a control means for driving a motor provided in the reel drive means.