JPS6243861A - Rotary magnetic sheet device - Google Patents

Abstract

PURPOSE:To prevent almost the effect of leakage magnetic flux onto recording or reproduction by arranging a magnet directing a magnetic pole in a direction opposite to the direction of magnetic pole of an adsorbing magnet so as to cancel nearly the magnetic flux at the magnetic head position. CONSTITUTION:A spindle 6, a permanent magnet 7 and a magnetic head 5 are provided turnably and movably n radially to a main body 10 of a rotary magnetic sheet device, and a positioning pin 13 of a jacket 1 and a lower guide plate 11 having a head moving hole 12 are provided. A canceling magnet 14 to cancel the leakage magnetic flux of the adsorbing permanent magnet 7 is provided to the main body 10 by a mounting base 15 at a position nearly opposite to the permanent magnet 7 while clipping the magnetic head 5. The direction of magnet poles of each magnet is arranged to be opposed to each other and the leakage magnetic flux affected on the magnetic head 5 is canceled by two magnets.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a rotating magnetic sheet device in which a magnetic sheet is attracted and positioned on a rotating table by a permanent magnet.

[Background of the invention]

As a method for positioning the magnetic sheet at a predetermined position on the rotary drive shaft, for example, the method described in the magazine Nikkei Electronics 1984
．． As seen in the electronic still camera standards of 7-2 P and 80, there is a system in which the attraction yoke on the back surface of the sheet is attracted by a permanent magnet. In this case, the attraction force of the magnet must be such that it does not affect signal recording or reproduction of this rotating magnetic sheet device. However, in order to obtain reliable positioning, it is necessary to increase the adsorption force, and in this case, there is a risk that adverse effects such as an increase in distortion and a decrease in the reproduction level may occur during recording or reproduction.

FIG. 4 is a perspective view showing the main parts of a conventional rotating magnetic sheet device.

In the figure, reference numeral 1 indicates a magnetic sheet jacket, in which a rotating magnetic sheet 2 is rotatably housed. At the center of the magnetic sheet 2, a center core 5 made of a magnetic ring-shaped attraction yoke (not shown) and synthetic resin is provided integrally with the magnetic sheet 2. A part of the jacket 1 is provided with openings 4 on the top and bottom sides, and a guide plate (not shown) for stabilizing the rotation of the magnetic sheet 2 can be inserted from above and below. .

Further, 8 is a positioning hole for positioning the jacket on the device.

Then, the magnetic head 5 is inserted into the magnetic sheet 2 from the opening on the lower surface side.
is brought into contact with. This is a spindle for rotationally driving the 6-piece magnetic sheet 2. A permanent magnet 7 is provided near the outer periphery, and when the center core 5 of the magnetic sheet 2 is fully inserted, the attraction yoke of the center core 6 is attracted to the magnetic sheet 2. The magnetic sheet 2 is positioned with respect to one end surface 6α.

As a result, the magnetic sheet 2 and spindle 6 are integrally coupled and rotated, and the magnetic head 5 records/reproduces signals.

Here, the spindle 6 is made of a non-magnetic material to prevent dust such as iron powder from adhering to the reference end face because it is necessary to accurately position the center core 3. If a strong magnet is used, leakage magnetic flux magnetizes the magnetic head 5, causing deterioration in recording and reproducing performance.

[Purpose of the invention]

The present invention was proposed in view of the above-mentioned circumstances, and provides a rotating magnetic sheet device that has almost no influence of leakage magnetic flux on recording or reproduction even when the adsorption force of the magnetic sheet is sufficiently secured. The purpose is to provide.

[Summary of the invention]

In order to achieve the above-mentioned object, the magnetic sheet device of the present invention has a magnetic pole facing in a direction opposite to the magnetic pole direction of the attracting magnet at a position opposite to the attracting permanent magnet with the recording or reproducing magnetic head in between. By arranging the magnets, the magnetic flux at the position of the magnetic head is almost canceled out, so that the influence on recording or reproduction can be ignored.

[Embodiments of the invention]

The present invention will now be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of the present invention. In the figure, the main body of the 10-digit rotating magnetic sheet device is shown, and the main body includes the above-mentioned spindle.

6. A permanent magnet 7 and a magnetic head 5 are each provided rotatably and movably in the radial direction of rotation, and a lower guide plate 1 having a positioning pin 13 for positioning the jacket 1 and a hole 12 for moving the head is provided. It is being Furthermore, in order to cancel the leakage magnetic flux of the permanent magnet 7 for attraction, a canceling magnet 14 is mounted on the base 15 of the main body 10 and placed at a position almost facing the permanent magnet 7 with the magnetic head 5 in between. It is provided. FIG. 2 shows these structures in cross section along line A-A'.

In FIG. 2, 21 is an upper guide plate for stably rotating the magnetic sheet 2. Further, 3α indicates a suction yoke that is integrated with the center core 3. As shown in the figure, the canceling magnet 14 is provided on a line connecting the permanent magnet 7 and the magnetic head 5 at a position facing the permanent magnet 7 with the magnetic head 5 in between.

Here, the direction of the magnetic poles of each magnet is as shown in Figure 4, so that the magnetic poles are arranged in opposite directions between each magnet.
Leakage on magnetic head 5, 4.

As shown by the dotted line, the magnetic flux acts on the two magnets so as to cancel each other out, and as a result, the influence on the magnetic head can be ignored and suppressed.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to obtain a rotating magnetic sheet device in which the influence of leakage magnetic flux of the attracting magnet can be made almost negligible, and a stable positioning attracting force can be obtained. .

[Brief explanation of drawings]

FIG. 1 is a perspective view showing one embodiment of the present invention, and FIG. 2 is a perspective view showing one embodiment of the present invention.
FIG. 5 is a schematic diagram showing the operating situation in the case of the present invention, and FIG. 3 is a perspective view showing the main parts of a conventional rotating magnetic sheet device. Explanation of symbols

Claims (1)

[Claims] A rotating magnetic sheet device comprising a sheet rotating table having a first permanent magnet for adsorbing and fixing a center core of a magnetic sheet, and a magnetic head for recording and reproducing data in sliding contact with the magnetic sheet, in which the magnetic head is sandwiched. A second permanent magnet is attached to the sheet rotating table at a position substantially opposite to the first permanent magnet.
A rotating magnetic sheet device characterized in that a permanent magnet is provided, and each leakage magnetic flux caused by the first permanent magnet and the second permanent magnet cancels each other out in the magnetic head.