JPS61117751A - Correcting method of loose winding of magnetic tape - Google Patents

Abstract

PURPOSE:To easily correct the loose winding of the magnetic tape by performing the tape-running starting control with a speed slower than the specific speed, and the halting control with a speed faster than the specific speed if a loose winding of the magnetic tape is detected by means of the output of a tension sensor. CONSTITUTION:A tape (a) on the part of tape reel 2 tends to continue its rotation in clockwise direction by its own inertia moment. But the reel 2 itself stops as demanded because it is directly connected with the DC motor. Therefore, the tape (a) inclines to cause a layer-discrepancy in the direction to tighten itself. If the winding of the tape (a) is loose,the atmost outer layer of the tape (a) on the reel 2 stops slightly later than the reel 2, and enlarges the difference between the length of winding by a reel 1 and the length of feeding by the reel 2, by which the swinging angle of a tension arm 6-2 becomes larger. The angle of this swinging of the arm 6-2 that largely exceeds the specified angle of swinging is detected by a detector 7, and an output signal is transferred to a controlling part 10 via a loose-winding detector 13. The controlling part 10 performs the tape-running starting control slower than the specified speed, and does the halting control with a deceleration larger than the specified one.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention inspects the magnetic tape for the presence or absence of slack before controlling the running of the Tlt1 tape, and when one tape is detected to be loose, the magnetic tape corrects it. This invention relates to a method for correcting tape winding loosening.

When starting and stopping a magnetic tape, in order to accurately record/reproduce information at a predetermined position on the magnetic tape, it is necessary to start and stop the magnetic tape accurately within a predetermined range and to stop accurately within a predetermined position. One of the conditions for realizing the above requirements is that the magnetic tape be wound around the tape reel with a predetermined tension.

On the other hand, recently, as the recording density on magnetic tape has improved, a reel-to-reel system in which the tape reel is directly driven by a motor to run the magnetic tape has come into practical use.

This reel-to-reel method is used in cassette-type external storage devices for information processing systems, but it has been empirically confirmed that tape winding loosens more frequently due to carrying the cassette than with large tape reels. There is.

It is desirable that such tape winding loosening be detected and corrected in advance.

[Prior art and problems to be solved by the invention] As a conventional technology, a cassette type magnetic tape device will be explained as an example.

FIG. 3 shows a block diagram of a cassette-type magnetic tape device, and FIG. 4 shows a configuration diagram of a tension sensor used in the cassette-type magnetic tape device.

The running speed of the magnetic tape a is detected and controlled by an output signal from a tachometer (not shown) installed in each DC motor (not shown) driving the tape reel 1.2.

That is, the radius ratio detector 8 detects the radius ratio information of the winding radii R1 and R2 of the magnetic tape a wound on the tape reel 1.2 based on the output signal from the nine tachometers (not shown).
The running speed information of the magnetic tape a is counted by the speed counter 9 based on the output signal from the tachometer for the tape reel 1 (not shown) and sent to the control section 10.

The control unit 1O includes a detector 8. Based on the information from the counter 9, the amount of winding of the magnetic tape a onto the tape reel l.

The load of the DC motor (not shown) is calculated so that the amount of feed from the tape reel 2 is the same, and the current corresponding to the load is determined.

Further, when controlling the running of the magnetic tape a, a constant tension is applied to the magnetic tape a, and this control is also determined by the current flowing through the DC motor (not shown).
The control unit 10 receives information regarding tension from the detector 7 via the tension sensor 6.

The comprehensive control current value is determined.

The tension of the spring d of the tension sensor 6 is set to be 1, for example, 100 g when the angle of the tension arm 6-2, which is determined by the tension of the magnetic tape a, is at the center C.

Further, the potentiometer 6-1 is a sensor for detecting the angle of the arm 6-2, and the detection result is sent to the detector 7. This output is adjusted so that zero volts are generated when the arm 6-2 is at the center C, a positive voltage is generated in the direction of the angle θ', and a negative voltage is generated in the direction of the angle θ'.

The control unit 10 determines the current to be applied to the DC motor (not shown) and controls the DC motor (not shown) via the respective motor driver 11.12. ) variation.

There is a difference in the amount of winding/feeding out of tape a due to tape friction and the like.

As a result, the tape tension cannot maintain the predetermined 100g, and the sensor 6 detects this from the angle of the arm 6-2.
Feedback is applied to the control unit IO so as to return to the center C. Therefore, if the winding/feeding amount of tape a is balanced, the swing of arm 6-2 during tape running, including rising/falling, will be kept to the necessary minimum (for example, within θ' to θ"). ing.

On the other hand, during the winding/feeding operation of tape a in the above state,
That is, it has been found that during a write/read control operation, the winding layer of tape a suddenly shifts, causing an abnormality in the subsequent processing operation of tape a.

This occurs when the winding of tape a is loose, and conventionally, to prevent this in advance, tape a
The entire process is re-wound at a slow acceleration, and then the write/read control operation is performed, but this method requires a long setup time before starting the normal processing operation.

Normally, the magnetic tape a is wound on the tape reel 2 side, and tape winding loosening occurs within the tape reel 2.

Further, the forward direction of the magnetic tape running is the b direction.

[Means for solving problems]

It is an object of the present invention to realize a novel method for correcting loosening of magnetic tape winding, which solves the above-mentioned problems. and when the means detects the loosening of the magnetic tape winding, a plurality of controls are provided for starting the magnetic tape running at a slower speed than a predetermined speed, and stopping the magnetic tape at a deceleration larger than the predetermined speed for the falling control. This problem is solved by the method of correcting the loosening of magnetic tape winding according to the present invention, which is repeated several times.

[Effect]

In other words, the deviation of the tape winding layer due to the loosening of the magnetic tape winding is
iffff- Occurs momentarily when the engine accelerates or decelerates.

Moreover, it has been empirically determined that if this occurs once or twice, or several times at most, it will not occur during subsequent runs of the magnetic tape.

Therefore, the present invention repeats several times the operation of slowly starting up the magnetic tape in the forward direction, running at a constant speed for a certain period of time, and then stopping it at a deceleration greater than the prescribed speed until the initial positioning for writing/reading operations. By actively causing a deviation in the tape winding layer, it becomes possible to easily correct tape winding loosening in a short period of time.

〔Example〕

The gist of the present invention will be specifically explained below with reference to embodiments shown in FIGS. 1 and 2.

FIG. 1 shows an embodiment of the cassette type magnetic tape device according to the present invention, and FIG. 2 shows a control diagram for correcting the loosening of the magnetic tape according to the present invention. The same symbols indicate the same objects throughout the figures.

In this embodiment, it is assumed that the control according to the present invention is carried out from the beginning of the magnetic tape a until it is positioned at the writing/reading position, that is, the 80T (abbreviation for beginning of tape) position.

First, positioning to the BOT position is done when traveling.

The control unit 10 performs start-up control as shown in FIG. 2(B), performs slow start-up (several times the normal start-up shown in FIG. 2(A)), accelerates running e', and firstly performs constant speed running. Perform r' (speed of writing/reading).

When the constant speed running f' is reached, the control immediately shifts to deceleration running g'. In the deceleration running g' control, a large deceleration current is applied to a DC motor (not shown) so that the motor stops rapidly at a fraction of the normal speed shown in FIG. 2(A).

At this time, the tape a of the two tape reels tries to continue rotating clockwise due to its own moment of inertia, but since the tape reel 2 itself is directly connected to a DC motor (not shown), it stops at a predetermined time. . As a result, tape a tends to cause layer displacement in the direction of tightening.

If tape a is loosely wound at this time, the outermost layer of tape a on reel 2 will stop a little later than reel 2. This increases the difference between the amount of take-up of the reel 1 and the amount of payout of the reel 2, which increases the swing of the tension arm 6-2.

The detector 7 detects this as a deflection that greatly exceeds the deflection angles θ' and θ'' of the arm 6-2, and the slack detector 13 that receives this output detects that the tape winding is loose, and controls the output signal. output to section 10.

The control unit 10 checks this output signal and determines whether to perform the above control again. If there is no output from the slack detector 13, a predetermined speed, that is, normal driving control as shown in FIG.

With initial positioning, run to the position.

The tape winding distortion can be almost completely corrected by repeating the above control operation two or three times, that is, within 1 m of tape length.

〔Effect of the invention〕

According to the present invention as described above, there is an effect that tape winding loosening can be almost completely corrected by a simple method in a short period of time before reaching the area where write/read control is performed.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of a cassette-type magnetic tape device according to the present invention. FIG. 2 is a control diagram for correcting loosening of magnetic tape winding according to the present invention. Figure 3 is a block diagram of a cassette type magnetic tape device. FIG. 4 is a configuration diagram of a tension sensor used in a cassette type magnetic tape device. are shown respectively. In fig. 1.2 is a tape reel, 5 is a magnetic head. 6 is the tension sensor. 6-1 is a potentiometer. 6-2 is the tension arm. 6-3 is a roller guide, and 7 is a detector. 8 is a radius ratio detector, 9 is a speed counter. IO is the control unit. 11.12 is the motor driver. 13 indicates the looseness detector 2, respectively. 1tl (Motor 2^) (To motor 1) Note 2 lead (,4) (To e-ta 2) (To e-ta 1) 4a θ'

Claims (1)

[Claims] A first tape reel that feeds out a magnetic tape, a second tape reel that winds up the magnetic tape that is fed out from the first tape reel, and a DC motor that directly drives each of the first and second tape reels. and a tension sensor for detecting the tension of the magnetic tape, further comprising means for detecting the loosening of the magnetic tape from the output of the tension sensor, and the means detecting the loosening of the magnetic tape. In such a case, a method for correcting loosening of magnetic tape winding, characterized in that the magnetic tape running start-up control is started at a speed slower than a predetermined speed, and the run-down control is stopped at a deceleration larger than the predetermined speed, which is repeated a plurality of times. .