JPH0818479B2 - Magnetic recording sheet erasing device - Google Patents

Description

The present invention relates to a magnetic sheet erasing device, in particular, a microcapsule is applied to a sheet substrate, and the microcapsule is sensitive to a magnetic field in a state of being suspended in a liquid. The present invention relates to a simple and reliable erasing device for a magnetic sheet in which a sensitive magnetic piece that changes its direction is sealed.

[Prior Art] A magnetic sheet coated with magnetic powder on a substrate to perform magnetic writing recording is widely used as a recording tape, a video tape, a magnetic card, or the like. However,
These magnetically recorded data must be read using a magnetic head or the like, and the contents cannot be directly visually inspected.

In order to meet such a conventional demand for visible display, a magnetic recording medium that magnetically performs a visible display has been proposed. For example, Japanese Patent Publication No. 40-19226 and U.S. Pat. No. 3,320,523.
No. 3221315 or No. 3013206.

As shown in FIG. 5, transparent or translucent microcapsules 11 are coated on a sheet substrate 10 such as a film or paper, and the inside of the microcapsules is filled with a transparent liquid 12. A sensitive magnetic piece 13 that floats in the liquid 12 and is sensitive to a magnetic field is enclosed in the inside thereof.

Therefore, when a vertical magnetic field φv is applied to this magnetic sheet as shown in FIG. 6, the sensitive magnetic piece 13 is vertically aligned with the sheet substrate 10 in the microcapsule 11 as shown in FIG. Incident light Li reaches the surface of the sheet and is reflected here, producing reflected light Lo.

Therefore, in this state, the color of the reflection surface of the sheet substrate 10 is visually observed from the outside.

On the other hand, when a parallel magnetic flux φp is applied to the sheet substrate 10 as shown in FIG.
Are aligned as shown, and the incident light Li from the outside is
It is reflected by 13 and becomes reflected light Lo, and the sensitive magnetic piece 13
The reflected light will be visually observed.

Therefore, if the state of FIG. 7 is set to the erased state, at this time, from the outside, the magnetic sheet presents the bright metallic color of the sensitive magnetic piece 13, while the vertical magnetic flux φv causes a predetermined portion to be partially projected as shown in FIG. If the writing state is set, this portion is visually recognized as a reflective surface of the sheet substrate 10, for example, black. If only a predetermined portion is written by the writing head as shown in FIG. 6, it can be easily visually recognized from the outside. The display can be read.

Therefore, according to such a magnetic sheet, it is possible to obtain a display sheet which can be repeatedly written and erased.

FIG. 8 shows the erasing action of the above-mentioned conventional magnetic sheet.

In FIG. 8 (a), the sensitive magnetic piece 13 in the microcapsule 11 has the typical directionality shown by the six types in the figure.

FIG. 8 (b) shows the erasing magnetic flux φp2 parallel to the plane of the drawing as shown.
Is added, at this time, the direction of the sensitive magnetic piece is changed as shown in the drawing.

However, in this state, some of the sensitive magnetic pieces 13 still have a direction in which the incident light passes therethrough, and the reflection action thereof is incomplete.

Therefore, as shown in FIG. 8 (c), an erasing magnetic flux φp1 perpendicular to the paper surface is required, and as a result, all the sensitive magnetic pieces are aligned so as to reflect the incident light.

Therefore, in the prior art, at least two separately provided erasing magnets or magnetic coils for erasing are required to give such erasing magnetic fluxes in two directions, which makes the erasing device large and There is a problem that a large amount of power for erasing is required.

In particular, conventionally, there has been a problem that it is not possible to obtain a small and simple erasing device because separate erasing devices are required for both side surfaces and upper surface of the magnetic sheet.

The present invention has been made in view of the above conventional problems,
It is an object of the present invention to provide an improved erasing device capable of surely performing an erasing operation with a simple structure.

[Means for Solving the Problems] In order to achieve the above object, the present invention applies a microcapsule, which is suspended in a liquid and has a magnetic field sensitive to a magnetic field sealed therein, to a sheet substrate to provide the above-mentioned A magnetic sheet erasing device that changes reflection characteristics according to the orientation of a magnetic piece, the path for transporting the magnetic sheet, and a pair of erasing magnets fixed respectively on both sides along the path,
The erasing magnet has a magnetic pole that is orthogonal to the transfer direction and parallel to the sheet surface, and the permanent magnets on both sides directly or through the yoke so that the orthogonal magnetic flux penetrates the magnetic sheet across the passage. The pair of permanent magnets on each side are characterized in that different magnetic poles are formed so as to form parallel magnetic flux substantially along the transfer direction and the parallel magnetic flux penetrates the magnetic sheet.

[Operation] Therefore, according to the present invention, the erasing magnetic flux in different directions can be applied to the magnetic sheet only by the erasing magnets provided on both sides of the passage through which the magnetic sheet is transported. That is, when the magnetic sheet passes through the erasing magnet, an erasing magnetic flux in the different direction is applied to the magnetic sheet by utilizing the relative position change between the sheet and the magnet, which ensures a reliable erasing action with an extremely simple structure. It can be performed.

[Embodiment] A preferred embodiment of the present invention will be described below with reference to the drawings.

 FIG. 1 shows a first embodiment of the present invention.

In the figure, the magnetic sheet 20 is transported as indicated by arrow A along a path 21 indicated by a chain line.

The magnetic sheet 20 in the drawing has the shape of a magnetic card or a data tag, but in the present invention, such a magnetic sheet 20 can also be used as a device for erasing while winding a long sheet in a roll shape. A feature of the present invention is that a pair of erasing magnets 22, 23 and 24, 25 are fixedly arranged on both sides of the passage 21. And each of these erasing magnets 22 to
25 has magnetic poles that are orthogonal to the transport direction A and parallel to the sheet surface of the magnetic sheet 20, so that the magnetic poles of each erasing magnet 22-25 are transverse to the magnetic sheet 20 transporting the passage 21. It becomes a penetrating pole.

Further, in the present embodiment, the erasing magnets 22 to 25 are arranged directly opposite to each other across the passage 21 so that the orthogonal magnetic flux penetrates the magnetic sheet 20.

Therefore, in FIG. 1, the erasing magnets 22 and 24 are arranged to face each other, and the erasing magnets 23 and 25 are arranged to face each other.

Therefore, the orthogonal magnetic flux φp1 generated between these facing magnet pairs
Applies a first reversing action to the sensitive magnetic piece 26 of the magnetic sheet 20.

Further, in the present invention, the permanent magnet pairs 22, 23 and 24, 25 arranged on each side of the passage 21 generate a parallel magnetic flux substantially along the transfer direction A, and the parallel magnetic flux penetrates the magnetic sheet 20. It is considered to be a heterogeneous pair.

As is clear from FIG. 1, the magnet pairs on each side are magnets.
The magnetic flux from 22 to 23 and the magnetic flux from the erasing magnets 25 to 24 respectively form a parallel magnetic flux φp2, which causes the erasing magnet group to perform a second direction changing action on the sensitive magnetic piece 26 of the magnetic sheet 20. give.

Therefore, according to the present invention, only the erasing magnets arranged on both sides of the passage 21 generate erasing magnetic fluxes in different directions.
It can be applied to 20 and enables reliable magnetic erasing with an extremely simple structure.

In FIG. 1, the magnetic sheet 20 has fine microcapsules coated on its surface as in the conventional case, and the sensitive magnetic pieces 26 suspended in a liquid are sealed in these capsules.

However, in FIG. 1, the sensitive magnetic piece 26 is shown in an extremely exaggerated and large size, and the erasing action of the sensitive magnetic piece 26 thus shown in the present invention will be described below.

The magnetic sheet 20 of FIG. 1 shows a state in which the display contents are written, and the sensitive magnetic pieces 26 are all standing in the direction perpendicular to the magnetic sheet 20, and as a result, the incident light is the surface color of the sheet substrate. It is reflected and gives a black display surface, for example as described above.

Of course, the direction of the sensitive magnetic piece 26 is different in each direction, but in the figure, it is shown in four typical directions.

FIG. 2 shows a state where the magnetic sheet 20 is partially erased by the orthogonal magnetic flux φp1, and the right half of the magnetic sheet 20 is used for the first erasing.

As shown in the drawing, each of the sensitive magnetic pieces 26 is rotationally driven by the orthogonal magnetic flux φp1 with its direction oriented in the width direction of the magnetic sheet 20.

Then, as shown in FIG. 3, when the magnetic sheet 20 is exposed to the parallel magnetic flux φp2, each sensitive magnetic piece 26 is given a second direction rotating action as shown in the figure, and as a result, the magnetic sheet 20 is rotated. All the sensitive magnetic pieces are parallel to the sheet surface, and the surface of the sensitive magnetic piece 26 forms an anti-slope with respect to the incident light.

As described above, according to the present invention, the orthogonal magnetic flux φp1 and the parallel magnetic flux φp2 can be created by using the spread of the magnetic flux with a simple magnet arrangement, and thereby the magnetic sheet 20 can be erased extremely easily. It will be possible.

In FIGS. 1 to 3, the actual vertical magnetic flux φp1 and the parallel magnetic flux φp2 have some inclination, but in the present invention,
Since the magnetic sheet 20 receives a magnetic force in different directions determined by such magnetic flux distribution while moving relative to the erasing magnet, the sensitive magnetic piece sequentially moves in that direction, and then passes through the erasing area. Can be rotated in a plane parallel to the magnetic sheet 20 with almost no leakage.

As described above, according to the present invention, the erasing flux can be generated in various directions with a small number of erasing magnets while utilizing the divergence of the magnetic flux, and the extremely efficient erasing action can be obtained.

FIG. 4 shows a second embodiment of the erasing device according to the present invention. The same members as those in FIG. 1 are designated by the same reference numerals, and corresponding members are designated by the reference numeral 100 in FIG. In addition, it is shown.

A feature of the second embodiment is that the pair of erasing magnets 122, 123 and 124, 125 arranged on both sides of the passage 21 do not directly oppose each other across the passage 21 in the width direction, but the transfer direction A
It is shifted along.

Further, in order to obtain a good orthogonal magnetic flux even with such a dislocated arrangement, yokes 130 and 131 are provided on each magnet pair 122, 123 and 124, 125.

The yoke 130 is in close contact with the erase magnet pair 122, 123, and the left end thereof is bent so as to be close to the passage 21, and extends to a position facing the erase magnet pair 124, 125 on the opposite side.

Similarly, the yoke 131 is also in close contact with the erasing magnet pair 124, 125, the central portion thereof is bent to be close to the passage 21, and extends to a position facing the erasing magnet pair 122, 123 on the opposite side.

Therefore, as shown in the drawing, the orthogonal magnetic flux φp1 extends from the erasing magnet 125 toward the yoke 130, and the orthogonal magnetic flux φp1 returns to the erasing magnet 124 again through the yoke 130.

Similarly, a reciprocal orthogonal magnetic flux φp1 is formed from the erasing magnet 123 toward the erasing magnet 122 via the yoke 131.

Further, the permanent magnet pairs 122, 123 and 124, 125 on both sides respectively form a parallel magnetic flux φp2 as in the first embodiment, and a parallel magnetic flux φp2 is also generated from the erasing magnet 123 to the magnet 124.

As described above, according to the second embodiment, the numbers of the orthogonal magnetic fluxes and the parallel magnetic fluxes can be reduced by shifting the arrangement on both sides of the passage 21 and compensating for the deviation by the yoke without increasing the number of erasing magnets. Magnetic flux is repeatedly applied to the sensitive magnetic pieces in different directions, and a reliable direction changing action is applied to the slow-moving sensitive magnetic pieces, and erasing can be performed reliably.

Increasing the frequency of direction change due to such repetitive rotation can give an effective erasing action even to a sensitive magnetic piece that is difficult to move, and it is also possible to write or erase the sensitive magnetic piece within the microcapsule. There is an advantage that the position can be easily maintained.

That is, such a holding action can be achieved by increasing the viscosity of the liquid in which the sensitive magnetic piece floats, and the difficulty of movement at this time can be eliminated by the repeated change in the rotation direction as in the second embodiment. it can.

In the embodiment, the erase magnet pairs arranged on both sides are shown as one set, but it is also preferable to provide a plurality of such sets in the present invention.

[Effects of the Invention] As described above, according to the present invention, it is possible to give a reliable erasing action to a magnetic sheet with an extremely simple structure, and in particular, downsizing and power saving of a magnetic sheet writing / erasing apparatus. It greatly contributes to.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a first preferred embodiment of a magnetic sheet erasing apparatus according to the present invention, FIGS. 2 and 3 are explanatory views of the erasing action in the first embodiment, and FIG. 4 is the present invention. FIG. 5 is an enlarged cross-sectional view of a magnetic sheet for performing a visible display used in the present invention, and FIG. 6 is an explanatory view showing a written state of the magnetic sheet. FIG. 7 is an explanatory view showing the erased state of the magnetic sheet, and FIG. 8 is an explanatory view showing the general erase operation of the magnetic sheet. 20 ...... Magnetic sheet 21 ...... Passage (22,23), (24,25) (122,123), (124,125) …… Erase magnet 130,131 …… Yoke A …… Transfer direction Φp1 …… Orthogonal magnetic flux Φp2 …… Parallel magnetic flux

Claims (1)

[Claims] 1. A sheet substrate coated with microcapsules encapsulating a sensitive magnetic piece floating in a liquid and sensitive to a magnetic field,
A device for erasing a magnetic recording sheet (hereinafter, referred to as a magnetic sheet) that changes a reflection characteristic depending on a direction of the sensitive magnetic piece, comprising: a passage for transporting the magnetic sheet; and a passage fixed along both sides of the passage. A pair of erasing magnets, the erasing magnet having magnetic poles orthogonal to the transport direction and parallel to the sheet surface, and permanent magnets on both sides so that orthogonal magnetic flux penetrates the magnetic sheet across the passage. Are opposed to each other directly or via a yoke, and the permanent magnet pairs on each side are formed as parallel magnetic fluxes substantially along the transfer direction and are formed as different pole pairs so that the parallel magnetic flux penetrates the magnetic sheet. An apparatus for erasing a magnetic recording sheet, characterized by: