JP2545451B2 - Magnetic tape erasing device - Google Patents

Description

The present invention relates to a magnetic tape for erasing a magnetic tape on which information is recorded such as an analog tape such as a video tape and an audio tape, and a digital tape used for a computer and the like. Regarding the erasing device.

[Conventional technology]

7 to 9 show a conventional magnetic tape erasing device disclosed in JP-A-61-170904. In these figures, 1 is a coil, and has a space 2 in the center. A roller 4 is arranged in the space 2, and the magnetic tape 3 wound around a reel is vertically inserted into the space 2 so as to come into contact with the roller 4.

Then, when a ringing current whose envelope gradually attenuates is passed through the coil 2, magnetic flux is generated in the space 2 in the vertical direction in the figure. This magnetic flux erases the information recorded in the portion of the magnetic tape 3 substantially parallel to this magnetic flux.
When the roller 4 is rotated, the magnetic tape 3 rotates,
The erased portion (the portion parallel to the magnetic flux) is sequentially changed, and eventually the entire portion can be erased.

[Problems to be solved by the invention]

In the conventional device, the coil 1 is thus wound so that the entire magnetic tape 3 is arranged in the space 2. Therefore, the coil 1 becomes long, the resistance increases, and an extremely large value of current has to be passed in order to generate a strong magnetic flux, resulting in a large power consumption and a large size of the device.

Therefore, the present invention reduces power consumption and enables the device to be downsized.

[Means for solving problems]

The magnetic tape erasing device of the present invention is wound such that a space is formed in the center and has a coil having a length and a width smaller than the winding diameter of the magnetic tape to be erased, and a partial area of the magnetic tape is a coil. Located inside the space of the magnetic tape and moving the magnetic tape so as to face the coil so as to move the magnetic tape in and out of the space of the coil, and the moving means so as to sequentially change the area of the magnetic tape facing the coil. The control means includes a control means, a generation circuit that generates a ringing signal when a part of the magnetic tape stops at a predetermined position facing the coil and supplies the ringing signal to the coil, and a detection means that detects the diameter of the magnetic tape. Calculates the number of areas from the detected diameter and coil width.

[Action]

When the coil is energized, a strong magnetic flux is generated in the space. When the magnetic tape is moved into the space of the coil by the moving means and stopped at a predetermined position, the recorded information on the magnetic tape is erased by the gradually decreasing magnetic flux generated by the coil. This operation is repeated for each area of the magnetic tape divided into a plurality of areas.

Therefore, power consumption can be saved and the device can be downsized.

〔Example〕

FIG. 2 shows the configuration of the magnetic tape erasing device of the present invention. In the figure, reference numeral 11 denotes a coil portion whose perspective view is shown in FIG. 3, which includes a coil 12 wound so as to form a space 14 in the center and a transparent member arranged outside the coil 12. And a core 13 made of a magnetic material.
The length of the coil 12 (space portion 14) is longer than the diameter of the magnetic tape to be erased, and its width is sufficiently smaller than the diameter of the magnetic tape.
Therefore, it is possible to insert the magnetic tape into the space 14.

Reference numeral 21 is a slider, which can be inserted into the space 14 of the coil 12. A motor 22 drives a roller 23 to move the slider 21 in the left-right direction in FIG. Reference numeral 24 is an encoder as a position detecting means of the slider 21, which outputs a signal corresponding to the moving position of the slider 21. Reference numeral 25 denotes, for example, a detection means composed of a pair of a light emitting element and a light receiving element, which irradiates the hole 26 formed in the slider 21 with light, receives the reflected light, and has the size of the magnetic tape 27 arranged on the slider 21. (Diameter) is detected.

FIG. 4 is a block diagram of the magnetic tape erasing device of the present invention. In the figure, reference numeral 32 denotes a control circuit including, for example, a microcomputer, which controls each circuit, means and the like in response to an input from the input means 31 including switches, buttons and the like. A drive circuit 33 drives the motor 22. Reference numeral 34 denotes a generator circuit, which, as shown in FIG. 5, generates an AC signal (ringing signal) whose envelope is gradually attenuated and supplies the AC signal to the coil 12. Reference numerals 35 and 36 denote a drive circuit and display means driven by the drive circuit, which are provided as necessary.

Then, the operation will be described. First, the magnetic tape 27 is placed at a predetermined position on the slider 21. Next, when the input means 31 is operated to command the start of the erasing operation, the control circuit 32 drives the motor 22 via the drive circuit 33, and the slider 21 is coiled.
Move to 12 space 14. The encoder 24 outputs a signal corresponding to the moving position of the slider 24 to the control circuit 32. When the slider 21 reaches a predetermined position, the control circuit
32 stops driving the motor 22 and stops the slider 21. At this time, as shown in FIG. 1, for example, approximately 1/3 of the magnetic tape 27 is the space of the coil 12 (coil 12c in FIG. 1).
It is inserted into the coil 14 and faces the coil 12 (12c). Next, the control circuit 32 controls the generation circuit 34 to generate a ringing signal and supply it to the coil 12. As a result, the recorded information in the area of the magnetic tape 27 inserted in the coil 12 (12c) is erased by the magnetic flux generated by the coil 12. The ringing signal is generated once or more times a predetermined number of times.

After generating the ringing signal a predetermined number of times, the control circuit 32 drives the motor 22 again to further move the slider 21 to the right in FIG. 2 and stop it at a predetermined position. At this time, the relative position between the magnetic tape 27 and the coil 12 is
In the figure, the coil 12a and the magnetic tape 27 are shown. That is, the approximately central third of the magnetic tape 27 faces the coil 12 (12c). In this state, the ringing signal is again generated from the generating circuit 34 a predetermined number of times.

When the control circuit 32 further moves the slider 21 and the positional relationship between the magnetic tape 27 and the coil 12 becomes the positional relationship shown by the magnetic tape 27 and the coil 12b in FIG. 1 when the second erasing operation is completed. Stop. That is, the last 1/3 area of the magnetic tape 27 faces the coil 12 (12b). At this position, the ringing signal is generated again a predetermined number of times.

When the third erasing operation is completed, the control circuit 32 rotates the motor 22 in the reverse direction to disengage the slider 21 from the space 14 and stop it at the initial position.

When information is recorded by magnetizing the magnetic tape 27 in the longitudinal direction, the most efficient erasing operation is performed when the direction of the magnetic flux generated by the coil 12 is made parallel to the magnetization direction of the magnetic tape 27. Done. Therefore the first
In the figure, the regions facing the coil 12a are the coils 12b and 12
It is erased better than the area facing c. However, the region facing the coils 12b and 12c can be erased to a practically sufficient level as long as the holding force is sufficiently smaller than the magnetic force generated by the coil 12.

If it cannot be erased enough, coil 12
In b and 12c, the number of times the ringing signal is generated can be increased or the current value thereof can be increased as compared with the case of the coil 12a. Further, when the above-described operation is regarded as one cycle, when the erasing operation of one cycle is completed, the magnetic tape 27 may be automatically or manually rotated by a predetermined angle, and then the above cycle may be repeated several times. When the erasing operation is repeated for a plurality of cycles, the number of cycles can be displayed on the display means 36, and the displayed value can be sequentially decreased each time the erasing cycle is repeated.

Also, the sixth tape is placed on the surface of the slider 21 on which the magnetic tape 27 is placed.
As shown in the figure, it is possible to display a mark 41 for judging the angle when the magnetic tape 27 is placed. In the case of this embodiment, it is assumed that the erase operation is performed for three cycles, and the direction in which the magnetic tape 27 is directed in each cycle is represented by three numbers 1, 2, and 3.

In the above, the magnetic tape 27 is divided into three areas,
The demagnetization is performed for each area, but the number of this section changes depending on the width of the coil 12 and the diameter of the magnetic tape 27.
Therefore, the number of divisions can be set automatically. At this time, the light emitting element of the detection means 25
The holes 26 of 21 are irradiated with light, and the magnetic tape 27
A plurality of detecting means 25 are arranged to receive the reflected light from and the amount of reflected light changes between the portion where the magnetic tape 27 does not exist and the portion where the magnetic tape 27 exists. Therefore, the control circuit 32 can determine the diameter of the magnetic tape 27 from the change in the light amount.
The control circuit 32 divides the diameter (diameter) of the magnetic tape 27 by the width of the coil 12 and automatically sets the number of sections from the quotient.

Alternatively, the number of categories can be manually input by the input means 31. At this time, the control circuit 32 displays the input value on the display means 36 via the drive circuit 35, and drives the slider 21 to be divided and driven by the input number of times in one cycle.

The core 13 serves to reduce the magnetic flux leaking to the outside and concentrate the magnetic flux in the space 14, but it may be omitted in some cases.

〔The invention's effect〕

As described above, according to the present invention, the magnetic tape is divided according to the diameter and width of the coil, and the erasing operation is performed for each area. Therefore, the length of the coil is shortened (and therefore the resistance is reduced). And reduce power consumption,
The device can be downsized.

[Brief description of drawings]

1 is a plan view showing the arrangement of a coil and a magnetic tape in a magnetic tape erasing device of the present invention, FIG. 2 is a side view of the magnetic tape erasing device of the present invention, and FIG. 3 is a coil of the magnetic tape erasing device. FIG. 4 is a perspective view, FIG. 4 is a block diagram of the magnetic tape erasing device, FIG. 5 is a waveform diagram of a driving current of a coil of the magnetic tape erasing device, and FIG. 6 is a plane of a mark on a slider of the magnetic tape erasing device. FIG. 7 is a perspective view of a conventional magnetic tape erasing device, FIG. 8 is a front view thereof, and FIG. 9 is a side view thereof. 1 …… Coil 2 …… Space 3 …… Magnetic tape 4 …… Roller 11 …… Coil part 12 …… Coil 13 …… Core 14 …… Space 21 …… Slider 22 …… Motor 23 …… Roller 24 …… Encoder 25 …… Detecting means 26 …… Hole 27 …… Magnetic tape 31 …… Input means 32 …… Control circuit 33 …… Drive circuit 34 …… Generating circuit 35 …… Drive circuit 36 …… Display means 41 …… Mark

Claims (5)

(57) [Claims] 1. Wound so that a space is formed in the center,
A coil having a length larger than the winding diameter of the magnetic tape to be erased and a width smaller than that of the magnetic tape, and the magnetic tape is placed in the space of the coil so that a part of the area of the magnetic tape is located inside the space of the coil and faces the coil. Moving means for moving in and out, control means for controlling the moving means so that the area of the magnetic tape facing the coil changes sequentially, and ringing when a part of the magnetic tape is stopped at a predetermined position facing the coil. A magnetic tape erasing device is provided with a generation circuit for generating a signal and supplying it to a coil, and a detection means for detecting the diameter of the magnetic tape, wherein the control means calculates the number of the areas from the detected diameter and the width of the coil. apparatus. 2. The magnetic tape erasing apparatus according to claim 1, further comprising input means for manually inputting the number of the areas. 3. The magnetic tape erasing device according to claim 1, wherein the magnetic tape erasing device further comprises display means for displaying the number of the areas. 4. A magnetic tape erasing apparatus according to claim 3, wherein the number displayed on said display means is sequentially reduced for each erasing operation of one cycle. 5. The magnetic tape according to claim 1, wherein a mark for determining an angle at which the magnetic tape is placed is displayed on a surface of the moving means on which the magnetic tape is placed. Erase device.