JPH0818480B2 - 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. 10, a transparent or semi-transparent microcapsule 11 is coated on a sheet substrate 10 such as a film or paper, and the inside of the microcapsule 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. 11, the sensitive magnetic piece 13 is vertically aligned with the sheet 10 in the microcapsule 11 as shown in FIG. The light Li reaches the surface of the sheet and is reflected here to generate 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, as shown in FIG.
When p is applied, the sensitive magnetic pieces 13 in the microcapsule 11 are aligned as shown in the figure, and the incident light Li from the outside is reflected by each of the sensitive magnetic pieces 13 to become a reflected light Lo, and the sensitive magnetic pieces 13 from the outside are reflected. The reflected light will be visually observed.

Therefore, if the state of FIG. 12 is set to the erased state, at this time, from the outside, the magnetic sheet takes on the bright metallic color of the sensitive magnetic piece 13, while as shown in FIG. When the writing state is set, this portion is visually recognized as a reflection surface of the sheet substrate 10, for example, black, and if only a predetermined portion is written by the writing head as shown in FIG. 11, it can be easily visually observed 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. 13 shows the erasing action of the above-mentioned conventional magnetic sheet.

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

As shown in FIG. 13 (b), the erasing magnetic flux φp2 parallel to the paper surface is 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. 13 (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.

Further, conventionally, there has been a problem that a uniform erasing magnetic flux cannot be applied to a magnetic sheet having a large display area, which limits the size 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 which can surely perform an erasing operation with a simple structure and which has no restriction on the size of a magnetic sheet to be erased.

[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 the reflection characteristics according to the orientation of magnetic pieces, comprising a path for transporting the magnetic sheet, and a plurality of erasing means having an upper surface or a lower surface of the path and a magnetic pole on a surface perpendicular to the magnetic sheet surface. A magnet is provided with a predetermined gap from the passage surface,
The erasing magnets are arranged at substantially equal intervals in the width direction of the magnetic sheet and sequentially shifted in a predetermined direction with respect to the moving direction of the magnetic sheet, and the sensitive magnetic pieces of the magnetic sheet are arranged along the magnetic sheet surface of the erasing magnet. The parallel magnetic flux is aligned in the surface direction of the magnetic sheet, and the next erasing magnet sequentially erases the erasure remaining area of the preceding erasing magnet as the magnetic sheet is moved.

[Operation] Therefore, according to the present invention, the magnetic sheet is partially erased by using the magnetic flux penetrating the magnetic sheet in parallel in the magnetic flux distribution of the erasing magnet, and such partial erasure is transferred to the magnetic sheet. The entire magnetic sheet can be reliably erased by sequentially erasing the erase tracks defined by the plurality of erasing magnets, which are sequentially displaced along the direction.

Therefore, according to the present invention, since the erasing magnets are sequentially aligned in the width direction of the magnetic sheet, when the sheet width is large, it is possible to surely erase a wide sheet surface only by increasing the number of permanent magnets.

Further, in the present invention, the magnetic poles of the erasing magnet are arranged in the direction perpendicular to the magnetic sheet surface or along the transfer direction. In the former case, the parallel radiating magnetic flux parallel to the magnetic sheet surface in the magnetic flux distribution contributes to the erasing, and in the latter case. In, the side magnetic flux penetrating the magnetic sheet surface in the magnetic flux distribution contributes to the erasing.

[Embodiment] FIG. 1 shows a first embodiment of an erasing device according to the present invention.

In the figure, the magnetic sheet 21 is guided along the passage 20,
In the present invention, a sheet guide 22 is provided to guide the magnetic sheet 21 through the passage 20 to the erasing section properly. As shown in FIGS. 1 and 2, the sheet guide 22 has guide walls 22a and 22b whose both side surfaces receive side surfaces of the magnetic sheet 21.
A guide groove 22c for transferring the magnetic sheet 21 is formed between a and 22b.

The sheet guide 22 is preferably made of, for example, Teflon resin or the like in order to transfer the magnetic sheet 21 with low frictional resistance.

A plurality of erasing magnets are embedded and fixed in the sheet guide 22 on one surface of the magnetic sheet 21 at a predetermined interval, and these magnets are denoted by reference numerals 31 to 37 in FIG. .

FIG. 2 shows the II-II cross section of FIG. 1, and as is clear from the figure, the erasing magnet, for example 33, is inserted into the through hole 40 formed in the sheet guide 22, and the erasing magnet 33 is placed above the erasing magnet 33. A predetermined gap is provided between the end face and the surface of the guide groove 22c, and the gap 41 is filled with Teflon resin or the like. Therefore, when the magnetic sheet 21 slides in the guide groove 22c and is transported, the erasing magnets 31 to 37 do not interfere with the sheet 21.

Further, in the present invention, if the through hole 41 is formed as a blind hole, there is an advantage that it is not necessary to fill the space between the magnet and the guide groove surface.

As is apparent from FIG. 1, the erasing magnets 31 to 37 are arranged so as to be sequentially displaced with respect to the transport direction A of the magnetic sheet 21.

The magnets 31 to 37 are provided at substantially equal intervals in the width direction of the magnetic sheet 21, that is, in the direction orthogonal to the transfer direction A.

As will be described later, the tilted arrangement of the magnets is necessary for the next magnet to erase the remainder of the erase of the preceding magnet, and for this reason, depending on the arrangement pattern of the magnets, the erasure of the magnetic sheet 21 may be directional. However, according to the arrangement pattern inclined toward one direction as shown in FIG. 1, even if the magnetic sheet 21 is fed in the direction A of FIG. The erasing action can be performed over the entire width of the sheet 21.

As is apparent from FIG. 1, since the next magnet erases the erase remainder of the preceding erase magnet, the arrangement of both ends of the magnet must exist outside the magnetic sheet 21, and the erase magnet 31, 37 is arranged outside the seat 21.

FIG. 3 is an explanatory view showing an erasing principle of an erasing magnet, for example, 31 in which magnetic poles in this embodiment are arranged perpendicularly to the magnetic sheet 21.

The illustrated magnet 31 has a magnetic flux distribution as shown by the arrow, but by providing an appropriate gap G between the magnet 31 and the magnetic sheet 21, a part of the distributed magnetic flux is distributed along the surface of the magnetic sheet 21 to the sheet 21. Is understood to pass through, and this magnetic flux is indicated by φp in FIG.

Therefore, as shown in the principle of the conventional magnetic sheet, if the sensitive magnetic pieces are aligned along the surface of the magnetic sheet 21, it can be erased, and φp in FIG. It is understood that it has an erasing effect.

In FIG. 3, the hatched portion indicated by the symbol E shows the region almost completely used for the erasing action.

FIG. 4 shows a state in which such an erasing action is viewed from the magnetic pole direction, and the area indicated by the ring E ₁ in the figure is an erasing area given to the magnetic sheet 21 with the erasing magnet 31 stationary.

In the present invention, since the erasing magnetic flux φp acts while the erasing magnet and the magnetic sheet move relative to each other, each sensitive magnetic piece of the magnetic sheet 21 moves in different directions as the magnetic sheet 21 is moved. It is affected by the erase magnetic flux φp.

Therefore, when the magnetic sheet 21 advances in the direction of arrow A in FIG.
Are sequentially applied in the direction along the surface of the magnetic sheet 21, and as a result, strip-shaped erased portions indicated by E ₂ and E ₃ are formed on the recording surface of the magnetic sheet 21.

The area indicated by the symbol H in FIG. 4 is erased by the erase ring area E ₁ that acts when the erase magnet is stationary, but when the erase magnet 31 and the magnetic sheet 21 move relative to each other. The portion written by the vertical magnetic flux in the vicinity of the magnetic pole of the magnet 31 is not erased and remains. in this way,
With a single erasing magnet, such an unerased area H is inevitably generated. In the present invention, in order to remove such an unerased area, a plurality of erasing magnets are arranged in a pattern staggered in the transfer direction. Is characterized by.

FIG. 5 shows the erased area of such a combined magnet, and it is understood that the next magnet sequentially erases the erased area by the preceding erased magnet, which is effective for the entire width of the magnetic sheet 21. Erasure is performed.

Further, according to the present invention, no matter how much the width of the sheet 21 increases, it is sufficient to sequentially increase the erasing magnets 31. Therefore, there is an advantage that the magnetic sheet width is not limited.

Further, FIG. 6 shows another arrangement pattern of the erasing magnets according to the present invention. The erasing magnets 13 are opened on both sides along the transfer direction A with respect to the erasing magnet 131 placed at the center of the passage 20.
2,133,134 and erase magnets 135,136,137 are arranged.

In this embodiment as well, the same erasing action as in the first embodiment described above is performed, but the erasing area along the transport direction A can be reduced to about half of that in the first embodiment, and when the sheet width is large. It is extremely effective.

Of course, in the second embodiment, when the magnetic sheet 21 is transferred in the direction opposite to the transfer direction A, the erasing magnet 31 provided at the center causes an unerased portion, so the transfer direction of the magnetic sheet is restricted to A. The need to do so arises.

FIG. 7 shows a third embodiment of the present invention, which has substantially the same structure and operation as the other embodiments described above, but in this embodiment, each erasing magnet 231 to 237 moves in its magnetic pole direction. It is characterized in that it is arranged parallel to the direction A.

FIG. 8 shows a cross section of the erasing magnet 233 as seen from the magnetic pole direction, and the side magnetic flux φp shown by the magnetic flux distribution in FIG. 9 is used for erasing.

That is, in the magnetic flux distribution, the magnetic flux φp penetrating through the side surface of the magnet is exactly parallel to the magnetic sheet 21 from the relationship between the erasing magnet 233 and the magnetic sheet 21 shown in FIGS. 7 and 8. And the areas E10 and E11 in FIG. 8 become erased areas.

Therefore, by comparing FIG. 9 with FIG. 3 of the first embodiment described above, it is understood that the erase area having a predetermined width can be selected as in the first embodiment.

Therefore, also in this second embodiment, a plurality of erase magnets are used.
By arranging 231 to 237 while sequentially shifting the positions with respect to the transport direction of the magnetic sheet 21, it is possible to perform a wide erasing action as in the first embodiment.

[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.

Further, according to the present invention, by increasing or decreasing the number of erasing magnets according to the width of the magnetic sheet, it becomes possible to perform a uniform erasing action on a magnetic sheet having an arbitrary width.

[Brief description of drawings]

FIG. 1 is a plan view showing a first embodiment of an erasing device according to the present invention, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG. 3 is a main part for explaining an erasing operation in the first embodiment. FIG. 4 is a sectional view, FIG. 4 is an explanatory view of an erasing region by a single erasing magnet showing an erasing action of the first embodiment, FIG. 5 is an explanatory diagram showing an entire erasing region of the first embodiment, and FIG. Is an explanatory view showing an erasing magnet arrangement pattern of the second embodiment of the present invention, FIG. 7 is a plan view showing the structure of the third embodiment of the present invention, and FIGS. 8 and 9 show the erasing action of the second embodiment. Explanatory diagram showing, FIG. 10 is an enlarged cross-sectional view of a magnetic sheet used for the present invention to perform a visible display, FIG. 11 is an explanatory diagram showing a writing state of the magnetic sheet, FIG. 12 is erasing of the magnetic sheet FIG. 13 is an explanatory diagram showing a state, and FIG. 13 is an explanatory diagram showing a general erasing action of the magnetic sheet. 20 …… Passage 21 …… Magnetic sheet 31-37,131-137,231-237 …… Erase magnet A …… Transfer direction Φp …… 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 an upper surface or a lower surface of the passage, which is perpendicular to the magnetic sheet surface. A plurality of erasing magnets each having a magnetic pole on its surface are provided with a predetermined gap from the passage surface. The erasing magnets are substantially evenly spaced in the width direction of the magnetic sheet and are sequentially shifted in a predetermined direction with respect to the transport direction of the magnetic sheet. The magnetic sensitive sheets of the magnetic sheet are aligned in the direction of the magnetic sheet surface by the parallel magnetic flux along the magnetic sheet surface of the erasing magnet. A magnetic recording sheet erasing device characterized by sequentially erasing.