JP3046212B2 - Magnetic display eraser - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic display erasing apparatus for a magnetic display medium such as a magnetic display sheet for performing a magnetic display by countless microcapsules in which a sensitive magnetic piece is inserted together with a dispersion medium. The present invention relates to a magnetic display erasing device for erasing a magnetic display obtained by the action of the above by a horizontal magnetic field.

[0002]

2. Description of the Related Art Magnetic display sheets which can be printed or erased by magnetism have been put to practical use. For example, as shown in FIG. 8A, countless microcapsules 104 are applied as magnetic display sheets 102 on the surface of a substrate 100 formed of a film, a sheet, or the like. Dispersion medium 1 such as liquid
With 06, sensitive magnetic piece 108 is enclosed which is sensitive to magnetic fields and floating Yu in the dispersion medium 106.

When a vertical magnetic field φv is applied to the microcapsules 104 of the magnetic display sheet 102 as shown in FIG.
(B), the sensitive magnetic piece 108 is magnetized and aligned in the vertical direction, the incident light Li reaches the surface of the substrate 100, and the reflected light Lo is obtained. In other words, the sensitive magnetic piece 10
As a result, the surface of the substrate 100 can be seen through the magnetic display sheet 102. Assuming that this state is a magnetic display, the perpendicular magnetic field φv is selectively acted on the magnetic display sheet 102, so that the sensitive magnetic piece 10
Desired characters, figures and the like can be displayed on the magnetic display sheet 102 by the verticalization of 8.

When a horizontal magnetic field φh is applied to the magnetic display sheet 102 on which such a magnetic display is obtained, the sensitive magnetic pieces 108 are aligned in the horizontal direction as shown in FIG. And the incident light Li is
8, and the reflected light Lo is obtained. As a result, coloring of the sensitive magnetic piece 108 appears on the magnetic display sheet 102, and at this time, the surface of the substrate 100 is hidden by the sensitive magnetic piece 108. When this is set to the erased state, the magnetic display generated by the vertical magnetic field φv is erased by the horizontal magnetic field φh.

[0005] As such a magnetic display erasing device for a magnetic display sheet, JP-A-4-174090, "Magnetic display erasing device for magnetic recording sheet" and JP-A-4-174,091 "Magnetic display erasing device for magnetic recording sheet", etc. There is.

[0006]

By the way, Japanese Patent Application Laid-Open No.
No. 174090 “Magnetic display erasing device for magnetic recording sheet”
For example, as shown in FIG. 9, the substrate 100 provided with the magnetic display sheet 102 to be erased is moved in a width direction orthogonal to the moving direction A by a plurality of magnets 112, 114, 116, 118.
And a horizontal magnetic field φh is applied. In this case, a parallel horizontal magnetic field φh can act on the magnetic display sheet 102. In such a magnetic display erasing device, a horizontal magnetic field must be applied to the entire width direction of the substrate 100 even when the magnetic display sheet 102 which is relatively small with respect to the outer shape of the substrate 100 such as a card is installed. This is inefficient, such as requiring an excessively large magnet to erase the magnetic display.

In Japanese Patent Application Laid-Open No. 4-174091, "magnetic display erasing apparatus for magnetic recording sheets", as shown in FIG. 10, a plurality of magnetic display sheets or the like are provided on one of the upper surface and the lower surface of a substrate 100. Magnets 120, 122, 124,
The substrates 126, 128, 130, and 132 are arranged so as to be shifted stepwise in the moving direction B of the substrate 100 at a certain interval. Further, as shown in FIG. 11, the N and S poles of the plurality of magnets 134, 136, 138, and 140 are oriented in the horizontal direction, and the magnets 134 to 140 are arranged on one side of the substrate 100.
Has been arranged.

As shown in FIG. 12, the erasing state of each magnet in such a magnetic display erasing apparatus is such that a non-erasable area H corresponds to the magnets 120 to 1 with respect to an erasing portion E indicated by oblique lines.
Regardless of the shape of 40, the magnetic display sheet 102 and the magnet 12
0 to 140 are present for the magnet width overlapping. In order to eliminate such an area H, a plurality of magnets 120 to 14
0 is displaced while being displaced. However, each magnet 120-
Magnets 120 to 14 to enlarge the erased portion E of 140
Increasing 0 has disadvantages such as an increase in the unerased portion H, and as a result, it has been difficult to reduce the size of the device. Further, when the magnets 120 to 140 are displaced and arranged in this manner, the magnets 120 to 140 displace the magnetic display sheet 102.
Are not strictly parallel magnetic fields. For this reason, a vertical magnetic field component similar to the magnetic field for display is generated outside the erasing area E, and this rotates the sensitive magnetic piece 108, so that that part cannot be used as the erasing area. For this reason, only a small part of the erasing ability of the magnets 120 to 140 can be used, which is inefficient.

Accordingly, an object of the present invention is to provide a magnetic display erasing device which is small in size and has improved erasing efficiency of a magnetic display.

[0010]

According to the magnetic erasing apparatus of the present invention, a horizontal magnetic field (φ) is applied to a magnetic display obtained by applying a vertical magnetic field to a magnetic display medium (magnetic display sheet 4).
By the action of h), a magnetic erasing apparatus for performing the erasing, the magnetic display magnet pairs are opposed to the pole at a position sandwiching the medium (6A and 6B, 6C and 6D, the electromagnet 6E
And 6F) are arranged, and the center point O of the magnet pair is
It is characterized by being located outside .

Further, the magnetic display is erased by moving a relative position between the magnet pair and the magnetic display medium.

The magnetic field formed by the pair of magnets is a planar magnetic field parallel to the magnetic display medium.

[0013]

In the magnetic erasing apparatus of the present invention, since the magnetic poles have the same polarity with the front and back surfaces of the magnetic display medium interposed therebetween, the lines of magnetic force coming out of the facing magnetic pole faces of the magnet pair repel each other, As a result, a plane magnetic field parallel to the magnetic display medium, that is, a horizontal magnetic field is formed. At this time, the center point O of the magnet pair
An unerased area occurs due to a blank area,
By setting the center point O, complete erasure becomes possible. The magnetic display formed by the vertical magnetic field is erased by the horizontal magnetic field formed by the magnet pair by changing the relative positional relationship between the magnet pair and the magnetic display medium. The erasing range is determined by a relative moving range between the two.

The pair of magnets installed on the front and back surfaces of the magnetic display medium can apply a strict horizontal magnetic field to the magnetic display medium, and a vertical magnetic field component orthogonal to the display surface of the magnetic display medium as in the prior art. Can be suppressed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments shown in the drawings.

FIGS. 1A and 1B show a first embodiment of a magnetic display erasing device according to the present invention. A magnetic display sheet 4 serving as a magnetic display unit is attached to a substrate 2 made of a plastic card or the like as a magnetic display medium for performing a magnetic display. The magnetic display sheet 4 includes, for example, an infinite number of microcapsules, as shown in FIG. 8A, and each microcapsule floats in the dispersion medium together with a dispersion medium such as a transparent liquid. In this manner, a sensitive magnetic piece sensitive to a magnetic field is sealed.

Magnets 6A and 6B are provided as magnet pairs as means for erasing the magnetic display on the magnetic display sheet 4 of the substrate 2 with the same poles facing each other. Magnets 6A, 6B
Are magnets of the same shape and the same strength. In the case of this embodiment, the shape is a disk, and the distance D between them is constant and the opposite side is N.
The magnetic display sheet 4 moves on the equidistant plane W within the interval D as shown by an arrow a, and the magnetic display sheet 4 moves relative to the magnets 6A and 6B.

The magnet 6 having the same poles disposed opposite to each other as described above
The magnetic field φh generated by A and 6B is a magnetic field having only in-plane components anywhere except the center point O on the equidistant plane W from the magnets 6A and 6B, that is, a plane magnetic field. At the center point O projected on the W plane from the center point O 'of the magnets 6A and 6B facing each other on the W plane, there is no magnetic field component offset by the sum of the facing magnetic fields. Thus, by arranging the magnetic sheet on a plane magnetic field formed by the magnet pairs, the magnetic sheet
So that the action of the horizontal magnetic field over and.

FIGS. 2A and 2B show the lines of magnetic force, FIG. 2A shows the lines of magnetic force in a section perpendicular to the W plane, and FIG. 2B shows the lines of magnetic force on the W plane. The line of magnetic force on the W plane is the center point O, that is, the center point O of the circle in the case of a circular magnet.
Is emitted on the radiation from the point where ′ is projected on the W surface, and a planar magnetic field φh is formed. When the polarities N and S are to be reversed, the directions of the lines of magnetic force may be reversed.

The magnets 6A and 6B may be triangular as shown in FIGS. 3A and 3B, or square as shown in FIGS. 4A and 4B. In this case, the lines of magnetic force radially emitted from the center point O vary in density according to the shape. However, when the magnets 6A and 6B are arranged in parallel, the center point O This corresponds to the projection point of the center of gravity O 'of 6A, 6B.

FIG. 5 shows that, by applying a perpendicular magnetic field to the magnetic display sheet 4, the sensitive magnetic piece is set up vertically to perform magnetic display, and then the magnets 6A and 6A are sandwiched by the magnetic display sheet 4.
B is arranged and the substrate 2 is moved in the direction of arrow a. FIG. 5A shows an erased state in the case of circular magnets 6A and 6B, and FIG. 5B shows a triangular magnet 6A and 6B.
FIG. 5C shows the erased state in the case of B, and FIG. 5C shows the erased state in the case of the magnets 6A and 6B having a rectangular shape. 8 is a magnetic display and 10 is an erased portion. In the case of erasure of these magnetic displays, since the center point O moves while being hung on the magnetic display sheet 4, the base line 12 indicating an unerased region due to the effect of the blank portion of the magnetic field at the center point O is set. Occurs. And
The base line 12 can also be used as a mark indicating a state in which erasing has been performed.

Since the portion where the base line 12 is formed passes through the center point O and is parallel to the moving direction of the magnetic sheet, as shown in FIGS. 1, 3 and 4, the magnets 6A, 6B
By setting the erasure area of the magnets 6A and 6B outside the range of the magnetic display sheet 4, that is, outside the range in which the base line 12 is generated, the center point O 'of the magnetic display sheet 4 is erased.
By applying a horizontal magnetic field φh to the magnetic display sheet 4 without generating the base line 12, the magnetic display can be completely erased. Even when the erasing area is set in this manner, the area other than the base line 12 can be set as the erasing area even in the portion where the magnet pair and the display sheet overlap, as compared with the conventional erasing apparatus, so that the erasing area is increased. In addition, since an ideal horizontal magnetic field can act on the magnetic display sheet 4, the erasing efficiency can be improved. Moreover,
Since a minimum number of magnet pairs, such as a pair of magnets 6A and 6B, need only be installed in the vicinity of the magnetic display sheet 4, it is not necessary to install magnets that apply a magnetic field to portions other than the magnetic display sheet 4, and erasing is performed. The size of the device can be reduced.

FIG. 6A shows a magnetic display erasing apparatus according to a second embodiment of the present invention. In this embodiment, the magnets 6C and 6D on the disk are arranged symmetrically with respect to the plane W at an angle of less than 90 degrees. Thus, the magnets 6C, 6D
Is arranged, as shown in FIG. 6B, the magnetic center point O is a position where the solid angle ω is maximum on the W plane,
No magnetic field component is generated at this position. The magnetic field in this case is
As compared with the cases shown in FIGS. 2A and 2B, the plane becomes flatter, but the magnetic field having only in-plane components, that is, the plane magnetic field φh, on the W plane other than the point O is the same as in the first embodiment. Will be formed. By disposing the display sheet on the W surface, a horizontal magnetic field can be applied to the magnetic sheet.

As described above, the magnets 6A and 6B of the first embodiment
As is clear from the magnetic field distribution due to the arrangement of the magnets 6C and 6D of the second embodiment, in order to form a horizontal magnetic field with respect to the magnetic display sheet 4 on the W surface, the magnetic field generated by each magnet It is understood that it is only necessary to be plane-symmetric with respect to the W plane.
Then, when the magnetic display sheet 4 is moved on the W surface having a magnetic field strength capable of rotating the sensitive magnetic piece in the magnetic display sheet 4, a horizontal magnetic field can be applied to the magnetic display sheet 4, and characters such as characters can be applied. The magnetic display can be erased.

FIGS. 7A and 7B show a third embodiment of the magnetic display erasing device according to the present invention. Magnets 6A and 6B of the first embodiment, magnets 6C and 6D of the second embodiment
May be an electromagnet as shown in FIG. In this embodiment, the electromagnets 6E and 6F are configured by winding a coil 62 around a disk-shaped magnetic core 60 similar to the first embodiment. In this case, the magnetic core 60 is exposed from the end face of the coil 62 in order to avoid contact between the coil 62 and the magnetic display sheet 4. When the electromagnets 6E and 6F are used, the magnetization can be stopped by canceling the exciting current of the coil 62.
Since it is not necessary to take measures such as retracting the magnet when the magnetic display is not erased from the magnetic display sheet 4, the structure can be simplified. Further, the electromagnet can generate a horizontal magnetic field by applying an exciting current to the coil 62, so that the magnetic display can be erased without any relative movement with respect to the magnetic display sheet.

As another embodiment, the magnets 6A and 6A
B or the magnets 6C and 6D may be arranged so as not to overlap the magnetic display sheet 4. When the area of the magnetic sheet 4 becomes large, a plurality of pairs of magnets are arranged at predetermined intervals, as in the related art, to erase the baseline 12 generated by the erasure of the magnetic display by each pair of magnets. Meanwhile, the erasing may be completed. Even with such a plurality of magnet arrangements, the erasing area of each magnet pair is enlarged as compared with the conventional erasing device, so that the number of magnets to be installed can be reduced.

The planar shapes of the magnets 6A, 6B, 6C, 6D or the electromagnets 6E, 6F may be polygons such as pentagons,
Various shapes such as a semicircle, a quarter circle, and an ellipse can be used.

[0028]

As described above, according to the present invention,
A pair of magnets having the same polarity is arranged at a position sandwiching the magnetic display medium, and the center point O of the magnet pair is positioned outside the magnetic display medium.
As a result, it is possible to apply a horizontal magnetic field to the magnetic display medium, which not only can improve the erasure efficiency with a small size than the conventional device, but also can cause an unerased area on the display medium.
No.

[Brief description of the drawings]

1A and 1B show a first embodiment of a magnetic display erasing device according to the present invention, in which FIG. 1A is a plan view and FIG. 1B is a vertical view.

FIGS. 2A and 2B show lines of magnetic force of the magnet shown in FIG. 1, wherein FIG. 2A is a diagram showing a vertical cross section, and FIG.

3A and 3B show a modification of the first embodiment of the magnetic display erasing device of the present invention, wherein FIG. 3A is a plan view and FIG. 3B is a vertical view.

FIGS. 4A and 4B show a modification of the first embodiment of the magnetic display erasing device of the present invention, wherein FIG. 4A is a plan view and FIG.

FIG. 5 shows an example of an erased state of a magnetic display of the magnetic display erasing device of the present invention, where (A) shows a case of a circular magnet;
(B) is a diagram showing a case of a triangular magnet, and (C) is a diagram showing a case of a quadrangular magnet.

6A and 6B show a second embodiment of the magnetic display erasing device of the present invention, wherein FIG. 6A is a diagram showing the magnet arrangement, FIG. 6B is a diagram showing a vertical cross section of the magnetic field, and FIG. FIG.

7A and 7B show a third embodiment of the magnetic display erasing device of the present invention, wherein FIG. 7A is a plan view and FIG. 7B is a side view.

8A and 8B show a magnetic display sheet and its operation, FIG. 8A is a cross-sectional view of the magnetic display sheet, FIG. 8B is a cross-sectional view showing the magnetic display state, and FIG. 8C is a cross-sectional view showing the magnetic erase state. is there.

FIG. 9 is a plan view showing a conventional magnetic display device.

FIG. 10 is a plan view showing another conventional magnetic display device.

FIG. 11 is a plan view showing another conventional magnetic display device.

FIG. 12 is a plan view showing an erased state of one magnet in a conventional magnetic display device.

[Explanation of symbols]

 4 Magnetic display sheet (magnetic display medium) 6A, 6B, 6C, 6D Magnet pair

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G09F 9/30-9/46

Claims (3)

(57) [Claims] 1. A magnetic display erasing apparatus for erasing a magnetic display medium by applying a horizontal magnetic field to a magnetic display obtained by applying a vertical magnetic field to the magnetic display medium, wherein the magnetic display medium has a position sandwiching the magnetic display medium. A magnet pair with the same poles facing each other , and a point at which the magnetic field strength of the magnet pair becomes zero.
The magnetic display medium is positioned outside the display surface of the magnetic display medium . 2. The magnetic display erasing device according to claim 1, wherein the magnetic display is erased by moving a relative position between the magnet pair and the magnetic display medium. 3. The magnetic field formed by the magnet pair:
2. The magnetic display erasing device according to claim 1, wherein the magnetic display medium has a plane magnetic field parallel to the magnetic display medium.