JP2002296622A - Manufacturing method for reversible image display medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a reversible image display medium capable of displaying an image of high contrast and good quality with a developer moving smoothly in each container cell as well as a method for the medium of which two substrates are easily removable so as to use repeatedly. SOLUTION: The manufacturing method for a reversible image display medium of which dry process developer DL including at least two kinds of dry process developing particles having triboelectric property, different electrostatic charge polarities and different optical reflection densities from each other is put in cells 16 between two substrates 11 and 12 is as follows; one side of the first substrate 11 is prepared to have projecting and recessing surface including recesses for the cells 16; After the developer DL is put in the recesses on the one side of the first substrate, the second substrate 12 is glued to the one side of the first substrate 11; the adhesion is performed by decompressing the inside of the cell 16 so as to contact the two substrates tightly to each other or by gluing them with a hot-melt adhesive of which appearing temperature of adhesiveness is lower than softening temperature of the developer or with a reactive hot-melt adhesive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display medium, and more particularly to a method for manufacturing a reusable reversible image display medium.

[0002]

2. Description of the Related Art Today's image displays include pencils, pens,
Write characters, graphics, etc. manually on an image display medium, such as paper, using paints, etc., display documents, graphics, etc., created by a computer, word processor, etc. on a display such as a CRT display, or print on a paper, etc. This is done by, for example, displaying an output on a medium.

Further, a document, a figure, or the like, which is manually created on a medium such as paper, or a document, a figure, or the like on a medium such as paper output by a printer is printed on another medium such as paper using a copying machine or the like. In some cases, a copy is made, or transmitted by a facsimile machine or the like, and copied and output on a medium such as paper at a transmission destination.

[0004]

Among these image displays, characters, characters and the like are displayed on an image display medium such as paper using a pencil, a pen or the like.
Image display for displaying figures, etc., and image display for displaying characters, figures, etc. on an image display medium such as paper by an image forming apparatus such as an electrophotographic system, an ink spraying system, a thermal transfer system, etc., such as a printer, a copying machine, or a facsimile machine. Then, a clear image can be displayed at a high resolution, and the image is easy to see when viewing the image.

However, it is not possible to repeat image display and image deletion on an image display medium such as paper. When writing letters and the like with a pencil, the letters and the like can be erased to some extent with an eraser, but if the letters etc. are thinly written, they will be completely erased if they are written with normal darkness. It is difficult to leave, and it is difficult to reuse a medium, such as paper, on which an image has been displayed, unless the image is also displayed on the back side of the medium on which an image has not been displayed.

[0006] Therefore, a medium such as paper on which an image is displayed is discarded or incinerated after it has been used up, and a lot of resources are consumed. In printers and copiers, consumables such as toner and ink are also consumed. Further, in order to obtain a display medium such as new paper, toner, ink, and the like, resources such as a medium and energy for manufacturing the medium are further required. This is contrary to the demand for environmental load reduction required today.

In this regard, in the image display on a display such as a CRT display, image display and image deletion can be repeated. However, the image displayed on the display has a lower resolution than the image displayed on a paper or the like by a printer or the like, and there is a limit to obtaining a clear and fine image. Since the resolution is low, it is not suitable for displaying a text document mainly composed of characters. A sentence or the like that fits into about one screen is still good, but a sentence or the like that continues over a plurality of screens is difficult to read and sometimes difficult to understand. In addition, eyes are very apt to be tired in long-term visual work due to relatively low resolution and light emission from the display.

As an image display method capable of repeating image display and image deletion, electrophoretic display (EP
D) and twisted ball type display (TBD) have been proposed. More recently, "Japan Hardcopy '99
PP249-252 "has been proposed.

In the electrophoretic display method, a sealed space is formed by arranging two substrates, at least one of which is transparent, at an interval with a spacer interposed therebetween to form a sealed space, in which particles having electrophoretic ability are formed. It is filled with a display liquid dispersed in a dispersion medium of a different color, and displays images in the color of the particles or the color of the dispersion medium by migrating particles in the display liquid in an electrostatic field. is there.

Such a display liquid is usually composed of a dispersion medium such as isoparaffin, fine particles such as titanium dioxide, a dye for imparting color contrast with the fine particles, a dispersant such as a surfactant, and additives such as a charge imparting agent. Is done.

However, in this electrophoretic display,
Since the contrast between the high refractive index particles (inorganic pigment) such as titanium dioxide and the insulating colored liquid is displayed, the degree of concealment of the colored liquid is inevitably low, and the contrast is reduced.

Furthermore, the types of dyes that can be dissolved in a high-concentration nonpolar solvent at a high concentration so as to enable electrophoresis of particles are limited. No black dye is known. Therefore, the background part is inevitably colored, and it is difficult to make the background part white and improve the contrast. When white particles for image formation are placed in the colored liquid, the colored liquid may enter between the white particle layer and the substrate that has moved to the image observation side substrate, or the colored liquid may be mixed between the white particles. And the contrast is reduced. Also, the resolution of the electrophoretic particles is low because it is difficult for the particles to be uniformly attached to the image observation side substrate.

Further, since the specific gravity difference between the particles and the dispersion medium in the display liquid is very large, and the particles are likely to settle and agglomerate,
The display contrast tends to decrease, and it is difficult to display images stably for a long period of time, and the previous display afterimage tends to occur. Further, the charging of the particles in the liquid greatly changes with time, and in this respect, the image display stability is also poor.

In the twisting ball type display method, a large number of microcapsules in which microspheres treated so that the half and the other half of the surface exhibit mutually different colors or optical densities together with an insulating liquid are held inside. Using an image display medium, a microsphere in the microcapsule is rotated by an electric field or a magnetic force to display an image in a predetermined color.

However, in this twisted ball type display, it is difficult to obtain a good contrast because an image is displayed by microspheres in an insulating liquid in a microcapsule, and in particular, a resolution is lowered because a gap is always formed between the microcapsules. . It is difficult to reduce the size of the microcapsule in order to improve the resolution in manufacturing the capsule.

"Japan Hardcopy '99 Transactions PP249-
252 ", an image display method is disclosed in which a sealed space is formed by opposing two substrates, each having an electrode and a charge transport layer, at a predetermined interval, and a conductive toner and a color therewith are formed therein. Insulating particles of different types are charged, an electrostatic field is applied to charge and charge the conductive toner, and the conductive toner is moved by Coulomb force to display an image.

However, in the image display method utilizing the charge injection phenomenon, when the charge-injected conductive toner moves,
Insulating particles (for example, white particles that are put together to obtain the background color) hinder the movement of the conductive toner, and some toners stop moving. As a result, sufficient image density and contrast cannot be obtained, and the image display speed decreases. In order to solve this problem, high voltage driving is required. Also, the resolution is limited to the resolution determined by the electrodes. In addition, it is essential to employ an electrode, a charge injection layer, and a conductive toner, and there is a limitation in manufacturing.

According to the inventor's knowledge, in order to solve the above-mentioned problems, (1) image display and image erasure can be repeatedly performed as compared with the conventional image display medium. It is possible to reduce the use of image display media such as paper and consumables such as developer and ink related to image formation, and to respond to the reduction of environmental load today. (2) High contrast and correspondingly high High quality images can be displayed. (3) High resolution, high quality images can be displayed. (4) Images can be displayed stably for a long time. (5) Afterimages are unlikely to occur, and therefore, good reversibility. The following reversible image display medium having the following basic configuration is proposed with the aim of displaying high quality images, (6) displaying images at high speed, (7) requiring a low driving voltage for image display, and the like. Is There. That is, two substrates facing each other with a predetermined gap, one or two or more developer storage cells formed between the two substrates and surrounded by a partition wall, and included in each of the cells. Having a dry developer, wherein the dry developers have different charging polarities from each other,
In addition, it is a reversible image display medium containing at least two types of dry-developed particles having triboelectric charging properties, which have different optical reflection densities.

This reversible image display medium forms an electrostatic field corresponding to an image to be displayed on the developing particles in a state where the developing particles contained in each cell in the image display medium are triboelectrically charged. Thereby, the developing can be performed by moving the developing particles by Coulomb force, and an image can be displayed.

The electrostatic field corresponding to the image to be formed can be obtained by providing electrodes on each of the medium constituting substrates, applying a voltage corresponding to the image to be formed between the electrodes, or applying an image to be formed on one of the substrates. Can be formed by forming an electrostatic latent image corresponding to.

Further, such a reversible image display medium is provided with two substrates facing each other with a predetermined gap therebetween, and one or two substrates formed between the two substrates and surrounded by a partition wall.
It has the above-mentioned developer accommodating cells and a dry developer contained in each of the cells, and the dry developers have different charging polarities and different optical reflection densities (another wording). In this case, at least two types of dry-developed particles having a triboelectric property are included.

Therefore, even after displaying an image once, the image can be erased by applying a different electrostatic field, by applying an alternating electric field, or by applying an oscillating magnetic field when magnetic developing particles are contained, An image can be rewritten by applying a different electrostatic field. Therefore, there is no need to discard the image display medium on which the image has been displayed. Further, the developing particles are contained in the cell, and therefore, there is no need to supply the developer from outside. As a result, the use of conventional image display media, such as paper, related to image display, and consumables such as developers can be significantly reduced.

Further, unlike the conventional electrophotographic image formation, it is not necessary to dissolve and fix the toner on a sheet such as paper by heat, and the image forming energy required for this type of conventional image formation is unnecessary. Can save most.

Thus, it is possible to respond to today's environmental load reduction.

According to the reversible image display medium, the developer contained in the cell contains at least two types of developing particles having different optical reflection densities, and the developing particles are dry developing particles. Since the degree of hiding of the other type of developing particles by one type of developing particles is good, an image can be displayed with good contrast.

The developer contained in the cell contains at least two kinds of mutually frictionally chargeable dry developing particles having mutually different charging polarities. When an image is displayed, the developer is charged to the opposite polarity by friction charging. Since the particles move under the Coulomb force, the particles are easy to move, and in this respect, the image can be displayed with good contrast, the afterimage of the previous display hardly occurs, the image can be displayed at a high speed, and further, low voltage driving is possible. .

Dry developing particles are less likely to settle and agglomerate because they do not involve a liquid, as compared with, for example, electrophoretic particles in a display liquid used for electrophoretic image display as described above. A decrease in contrast is unlikely to occur, and a long-term stable image display can be performed. Since the sedimentation and aggregation of the developing particles hardly occur, the afterimage of the previous display hardly occurs. Further, since dry development particles have less change over time in charging performance than particles in a liquid, stable image display can be performed for a long time in this respect as well.

In addition, compared to the conventional image display using a CRT display or the like, an image can be displayed with high resolution and easily to the eyes.

As for the production of such a reversible image display medium, as a generally conceivable method, a substrate having a concave portion for forming the developer accommodating cell is formed on one surface, and a predetermined amount of the concave portion is formed in the concave portion of the substrate. After containing the dry developer, another substrate with an adhesive is placed thereon and bonded with the adhesive, or the substrate coated with the adhesive is placed before the adhesive has not dried yet. To form a cell having a dry developer therein.

However, in such a method, a large amount of the developing particles adhere to the pressure-sensitive adhesive or uncured adhesive used for bonding the substrates, and the adhered developing particles can no longer move. Because of the stopped developing particles, it becomes difficult for other developing particles to move, and as a result, a decrease in contrast and image quality in image formation is caused.

Accordingly, the present invention provides two substrates facing each other with a predetermined gap therebetween, and is formed between the two substrates.
It has one or more developer storage cells surrounded by a partition wall, and a dry developer contained in each of the cells, and the dry developers have different charging polarities, and
A method for producing a reversible image display medium comprising at least two kinds of dry developing particles having triboelectric charging properties having different optical reflection densities, wherein the developer contained in each developer containing cell is smoothly dispersed. An object of the present invention is to provide a method for manufacturing a reversible image display medium which is easy to move, has high contrast, and can display an image with good quality.

Further, according to the present invention, the two substrates are hardly peeled off,
It is an object to provide a method for manufacturing a reversible image display medium that can withstand repeated use.

[0033]

The present invention provides a method for manufacturing a reversible image display medium based on the following to solve the above-mentioned problems. That is, two substrates facing each other at a predetermined gap, and one or more developer storage cells formed between the two substrates and surrounded by a partition wall,
A dry developer encapsulated in each of the cells, wherein the dry developer has at least two types of dry development having different charging polarities and different optical reflection densities, and having frictional charging properties. A method for producing a reversible image display medium containing particles, wherein a first substrate preparing step of preparing a first substrate having a concave and convex shape including a recess for forming a developer accommodating cell on one side; A developer accommodating step of accommodating a developer in a concave portion on one surface of the first substrate, and the first substrate accommodating the developer in the concave portion so as to form a developer accommodating cell accommodating the developer; And a second substrate attaching step of attaching a second substrate to one side of the reversible image display medium.

Then, any one of the following is adopted as the second substrate attaching step. (A) depressurizing the inside of the developer accommodating cell to reduce the first
And the second substrate are brought into close contact with each other. (B) bonding the first and second substrates together using a hot melt adhesive having a temperature at which adhesiveness is lower than the softening temperature of the developer; (C) bonding the first and second substrates together using a reactive hot melt adhesive;

Regardless of the method of applying the second substrate, the reversible image display medium that allows the developer contained in each developer containing cell to move smoothly and to display images with high contrast and good quality. Can be obtained.

As for the close contact between the two substrates due to the reduced pressure in the cell, an adhesive is sandwiched between the two substrates at the peripheral portion of the substrate before the pressure is reduced in the cell, and before the adhesive is cured. The pressure inside the cell may be reduced. In this way, the two substrates are easily adhered to each other, and the adhered state can be maintained for a long time thereafter.

Also, the hot melt adhesive (b),
When using the reactive hot melt adhesive of (c),
It is possible to obtain a reversible image display medium in which the two substrates are hardly peeled off and can withstand repeated use.

The hot melt adhesive (b),
When the reactive hot-melt adhesive (c) is used, a small amount of developing particles may adhere to the adhesive, but the amount of the adhesive may be the above-mentioned conventional adhesive or uncured adhesive. As compared with the case where the reversible image display medium is used, it is suppressed to such an extent that there is no practical problem.

[0039]

Embodiments of the present invention will be described below with reference to the drawings.

First, an example of a reversible image display medium will be described with reference to FIGS.

The reversible image display medium 1 shown in FIG. 1A includes a first substrate 11 and a second substrate 12. The substrates 11 and 12 face each other with a predetermined gap therebetween. A partition 13 is provided between the substrates 11 and 12, and the partition 13 ensures a predetermined gap between the two substrates. That is, the partition 13 is formed on both substrates 1.
Also serves as a spacer between 1 and 12. Also, both substrates 11,
Numeral 12 is adhered with a partition wall 13 therebetween, for example, by bonding with an adhesive. The partition 13 is the first in the illustrated example.
It is formed integrally with the substrate 11.

The first substrate 11 is, but not limited to, a transparent substrate here, and is formed of an insulating material. For example, it is formed of a light transmitting plate such as a transparent glass, a transparent resin film, or the like.

The partition 13 is also a partition wall forming the developer accommodating cell 16. That is, the partition 13 is formed as shown in FIG.
As shown in (A), a plurality of partition walls 13a extending in parallel with the longitudinal side of the medium 1 and partition outer walls 11 on both side ends.
In this case, a partition made of a and 11b is employed. A developer storage cell 16 is provided between each adjacent partition wall. Each cell 16 contains mutually triboelectrically charged white developer particles W.
A developer DL containing P (negative charge) and black developing particles BP (positive charge) is stored. Here, the white developing particles WP
Is negatively charged and the black developing particles are positively charged.

Each partition wall 13a has a width α and a height h, and the interval between adjacent partition walls is pt. Cell 1
The number, shape, etc. of 6 need not be limited to those shown.

The second substrate 12 is not limited to that,
For example, it is formed of a light transmitting plate such as a transparent glass, a resin film, or the like.

At least one of the first and second substrates (at least the substrate on the image observation side) is a light-transmitting substrate,
More preferably, it is a transparent substrate.

In order to close both ends in the longitudinal direction of the cell, both ends of the first and second substrates 11 and 12 are sealed by an appropriate method (see FIG. 2A).

In the case of the medium 1 shown in FIG.
Before the cells 1 and 12 are brought into close contact with each other,
Numeral 6 is open at both ends in the longitudinal direction. However, each cell 16 may be provided with an outer wall at both ends in the longitudinal direction. The medium 1 using the substrate 11 thus formed is shown in FIG.
It is shown in (B). In the medium 1 shown in FIG.
An outer peripheral wall 11 'surrounding all of the upper plurality of cells 16 is formed. The second substrate 12 is added to each partition wall 13a,
It is also made to adhere to the partition outer peripheral wall 11 '. In addition,
It is also possible to provide no wall 11 'at one end or both ends in the cell longitudinal direction, and seal that portion later.

In any case, each cell is finally sealed, so that the developer DL does not leak from the cell.

According to the reversible image display medium 1, for example, a) an electrostatic latent image corresponding to an image to be formed is directly formed on the first substrate 11, and b) an electrostatic latent image corresponding to an image to be formed. Contact the formed image carrier with the first substrate 11 (including proximity)
For example, by applying a developing particle driving electric field to the developer DL on the basis thereof, an image can be displayed as illustrated in FIG. 1B. If necessary, the second substrate 12
May be set to a ground potential or the like.

According to the reversible image display medium 1, each cell 1
In a state where the developing particles WP and BP contained in the toner particles 6 are triboelectrically charged, an electrostatic field is formed corresponding to an image to be displayed on the developing particles, so that the developing particles are moved by Coulomb force. To develop and display an image.

The reversible image display medium 1 applies a different electrostatic field or an alternating electric field even after an image is displayed, and determines whether at least one type of developing particles, for example, black developing particles BP are magnetic image particles. For example, the image can be erased by applying an oscillating magnetic field, or the image can be rewritten by applying a different electrostatic field. Therefore, there is no need to discard the image display medium on which the image has been displayed. Further, there is no need to supply a developer from outside. As a result, the use of conventional image display media, such as paper, related to image display, and consumables such as developers can be significantly reduced.

Further, unlike the conventional electrophotographic image formation, it is not necessary to dissolve and fix the toner on a sheet such as paper by heat, and the image forming energy required for this type of conventional image formation is unnecessary. Can save most.

Thus, it is possible to respond to today's environmental load reduction.

According to the image display medium 1, the cell 16
Contains at least two types of developing particles WP and BP having different optical reflection densities (in other words, “different in contrast” or “different in color”). The developing particles are dry developing particles, and the degree of hiding of the other type of developing particles by one type of developing particles is good, so that an image can be displayed with good contrast. Since the developing particles charged to the opposite polarities due to the triboelectric charging included in the cell 16 move under the Coulomb force, the particles are easy to move, and in this respect, an image can be displayed with good contrast and an afterimage of the previous display occurs. It is difficult, it can display images at high speed, and can be driven at low voltage.

Dry developing particles are less likely to settle and agglomerate because they do not involve a liquid, as compared with, for example, electrophoretic particles in a display liquid used for electrophoretic image display as described above. A decrease in contrast is unlikely to occur, and stable image display can be performed for a long period of time.
Since the sedimentation and aggregation of the developing particles hardly occur, the afterimage of the previous display hardly occurs. Further, since dry development particles have less change over time in charging performance than particles in a liquid, stable image display can be performed for a long time in this respect as well.

Further, as compared with the conventional image display using a CRT display or the like, an image can be displayed with high resolution and easily to the eyes.

Next, an example of manufacturing a reversible image display medium will be described with reference to FIG. A comparative example is also described. Example 1 As shown in FIG. 3 (A), a width α = 50 μm and a height h = 1 on one surface of a 25 μm-thick polyethylene terephthalate (PET) film f1 for a partition wall.
A large number of 50 μm plate-like members p1 were stuck in parallel at a pitch PT = 350 μm, and this was used as a first substrate. Using a rubber blade (not shown), a predetermined amount of the developer DL was stored in the groove-shaped recess of the first substrate for forming the developer storage cell, as shown in FIG. 3B.

Thereafter, as shown in FIG. 3C, a 25 μm-thick PET film f2 was adopted as the second substrate.
An epoxy-based adhesive Ad1 is applied to the peripheral portion, and the second adhesive is applied to the first substrate with the adhesive interposed before the adhesive is cured.
The substrates were temporarily bonded, and at the same time, the inside of each developer accommodating cell was depressurized by vacuum suction from a nozzle NZ disposed between the two substrates, thereby bringing the two substrates into close contact with each other. The nozzle NZ is pulled out in a state where both substrates are brought into close contact with each other, and at the same time as the pulling-out, the adhesive Ad1 that has not been cured yet is removed.
The part after the drawing was sealed by using. Thus, a reversible image display medium capable of repeatedly and stably displaying an image can be obtained by bringing both substrates into close contact with each other.

Incidentally, in order to facilitate the decompression from each cell, if necessary, an air passage such as a minute notch may be formed in the partition wall (p1) between the cells. (Example 2) As shown in FIG. 3A, a width α = 50 μm and a height h = 1 on one surface of a 25 μm-thick polyethylene terephthalate (PET) film f1 for a partition wall.
A large number of 50 μm plate-like members p1 were stuck in parallel at a pitch PT = 350 μm, and this was used as a first substrate. Using a rubber blade (not shown), a predetermined amount of the developer DL was stored in the groove-shaped recess of the first substrate for forming the developer storage cell, as shown in FIG. 3B.

Thereafter, as shown in FIG.
A 25 μm-thick PET film f2 is used as a substrate, and a hot-melt adhesive Ad2 (Vylon 200 manufactured by Toyobo Co., Ltd.) is applied to the periphery of the PET film f2. Then, the second substrate was temporarily bonded, and at the same time, the inside of each developer accommodating cell was depressurized by vacuum suction from the nozzle NZ disposed between the two substrates, thereby bringing the two substrates into close contact with each other. As described above, the nozzle NZ was pulled out in a state where both substrates were brought into close contact with each other, and simultaneously with the pulling out, the portion after the drawing was sealed with the adhesive Ad2 that had not been cured yet. Thus, a reversible image display medium capable of repeatedly and stably displaying an image can be obtained by bringing both substrates into close contact with each other.

In the case of the second embodiment as well, in order to facilitate decompression from each cell, if necessary, partition walls (p
In 1), an air passage such as a minute notch may be formed.

Developer DL used in Example 2
The developing particles P1 made of a polyester resin having a lower softening point, which will be described in detail later, had a softening point of 150 ° C. In addition, the hot melt adhesive Ad2 had an adhesiveness developing temperature of 120 ° C. (Embodiment 3) As shown in FIG. 3 (A), on one side of a 25 μm thick polyethylene terephthalate (PET) film f1, a width α = 50 μm and a height h = 1 for a partition wall.
A large number of 50 μm plate-like members p1 were stuck in parallel at a pitch PT = 350 μm, and this was used as a first substrate. Using a rubber blade (not shown), a predetermined amount of the developer DL was stored in the groove-shaped recess of the first substrate for forming the developer storage cell, as shown in FIG. 3B.

Then, as shown in FIG. 3D, a hot-melt adhesive A having a thickness of 10 μm was formed on one side as a second substrate.
d2 (Toyobo Co. Byron 200) applied thickness 2
A 5 μm PET film f2 was placed on the first substrate with the adhesive interposed therebetween, and was subjected to a hot press treatment at 120 ° C. for 30 seconds. Thus, a reversible image display medium capable of repeatedly and stably displaying an image was obtained.

Developer D used in Example 3
The developing particles having a lower softening point in L are particles P1 described above.
And the softening point was 150 ° C. (Example 4) A stable image display is repeatedly performed in the same manner as in Example 3 except that a reactive hot-melt adhesive (here, a moisture-curable hot-melt adhesive) is used instead of the hot-melt adhesive Ad2. A reversible image display medium that can be obtained can be obtained.

The following are examples of reactive (reactive) hot melt adhesives.

1) KUM2000 (manufactured by Konishi Co., Ltd.) polyurethane-based operating temperature 110 ° C. to 120 ° C. 2) UM3000 (manufactured by Konishi Co., Ltd.) polyurethane-based operating temperature 100 ° C. to 120 ° C. (Comparative Example) As shown in FIG. Thus, on one side of a 25 μm-thick polyethylene terephthalate (PET) film f1, a width α = 50 μm and a height h = 15 for a partition wall.
A large number of 0 μm plate-like bodies p1 were stuck in parallel at a pitch PT = 350 μm, and this was used as a first substrate. Using a rubber blade (not shown), a predetermined amount of the developer DL was stored in the groove-shaped recess of the first substrate for forming the developer storage cell, as shown in FIG. 3B.

Thereafter, as shown in FIG. 3D, a hot-melt adhesive A having a thickness of 10 μm was formed on one side as a second substrate.
d2 (Toyobo Co. Byron 200) applied thickness 2
A 5 μm PET film f2 was placed on the first substrate with the adhesive interposed therebetween, and was subjected to a hot press treatment at 120 ° C. for 30 seconds.

In this comparative example, the developer D
In L, the developing particles P2 of the polyester resin having a lower softening point, which will be described in detail later, had a softening point of 110 ° C.

In the obtained reversible image display medium, the developer particles were aggregated by heat, and only an image having a low contrast was obtained.

The above-mentioned polyester resin developing particles P1,
P2 is as follows. (Polyether-based resin developing particles P1) Styrene and 2-
Ethylhexyl acrylate was adjusted to a weight ratio of 17: 3.2, and put into a dropping funnel together with digmyl peroxide as a polymerization initiator. On the other hand, polyoxypropylene (2,2) -2,2 was placed in a glass four-necked flask equipped with a thermometer, a stirrer, a falling condenser, and a nitrogen inlet tube.
2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, isododecenyl succinic anhydride,
Terephthalic acid, 1,2,4-benzenetricarboxylic anhydride and acrylic acid in a weight ratio of 42: 11: 11: 11.
It was adjusted to 8: 1 and charged together with dibutyltin oxide as a polymerization initiator. This was stirred in a mantle heater under a nitrogen atmosphere at 135 ° C. while styrene and the like were dropped from a dropping funnel, and then heated to 230 ° C. for reaction. The softening point of the obtained polyester resin was 150 ° C. (Polyether-based resin developing particles P2) thermometer, stirrer,
Polyoxypropylene (2.2) was placed in a glass four-necked flask equipped with a falling condenser and a nitrogen inlet tube.
-2,2-bis (4-hydroxyphenyl) propane,
Polyoxyethylene (2,2) -2,2-bis (4-
(Hydroxyphenyl) propane, isododecenyl succinic anhydride, terephthalic acid and fumaric acid in a weight ratio of 82: 7.
The mixture was adjusted to 7: 16: 32: 30 and charged together with dibutyltin oxide as a polymerization initiator. This was reacted in a mantle heater under a nitrogen atmosphere at 220 ° C. with stirring. The softening point of the obtained polyester resin is 11
It was 0 ° C. (Measurement of Softening Point of Resin) The softening point of the resin was measured using a flow tester (CFT-500: manufactured by Shimadzu Corporation), using a fine die (diameter 1 mm, length 1 mm), pressurization 20 kg /
cm ^2, the temperature corresponding to 1/2 of the height of the flow ending point from the flow starting point for a sample of 1 cm ² were melted runoff under the conditions of heating rate 6 ° C. / min and the softening point.

[0072]

As described above, according to the present invention, two substrates facing each other with a predetermined gap therebetween, and one or two substrates formed between the two substrates and surrounded by a partition wall. It has the above-mentioned developer containing cell and a dry developer contained in each of the cells, and the dry developer has at least two types of charge polarities different from each other and different optical reflection densities from each other. A method for producing a reversible image display medium containing dry developing particles having triboelectricity, in which the developer contained in each developer containing cell is easily moved smoothly,
It is possible to provide a method for manufacturing a reversible image display medium capable of displaying images with high contrast and good quality.

Further, according to the present invention, it is possible to provide a method for producing a reversible image display medium in which two substrates are hardly peeled off and can withstand repeated use.

[Brief description of the drawings]

FIGS. 1A and 1B show an example of a reversible image display medium, in which FIG. 1A is a cross-sectional view of the reversible image display medium before displaying an image, and FIG. FIG.

FIG. 2A is a perspective view of a first substrate having recesses arranged in a grid pattern in the medium shown in FIG. 1, and FIG.
Is a plan view thereof.

FIG. 3A is a cross-sectional view of a part of a substrate having a recess for forming a developer accommodating cell, and FIG. 3B is a cross-sectional view of a state where the developer is put in the recess of the substrate; FIG. 2C is a diagram showing a state in which the two substrates are brought into close contact by vacuum suction, and FIG. 2D is a diagram showing a state in which the two substrates are bonded together with a hot melt adhesive or the like.

[Description of Signs] 1 Reversible image display medium 11 First substrate 12 Second substrate 13 Partition wall 13a Partition wall 14a Seal 111a, 11b Partition outer wall 11 'Outer peripheral wall 16 Developer storage cell DL Developer WP White developing particles BP Black developing Particle 2 Initial resin substrate 20 Resin molded substrate 21 Resin material layer having higher softening point 22 Resin material layer having lower softening point 23 Groove-shaped recess 24 Partition wall f1, f2 PET film Ad1 Epoxy adhesive Ad2 Hot Melt adhesive NZ vacuum suction nozzle

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[Procedure amendment]

[Submission date] January 21, 2002 (2002.1.2
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2A is a cutaway view of a part of the medium shown in FIG.
FIG. 2B is a plan view showing the first substrate in the medium .
Media using an outer peripheral wall surrounding the cell
It is a top view which cuts out and shows a part .

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kenji Otokawa 2-3-1-13 Azuchicho, Chuo-ku, Osaka-shi, Osaka Inside Osaka International Building Minolta Co., Ltd. (72) Inventor Denji Noda, Chuo-ku, Osaka-shi 2-3-13 Azuchicho Osaka International Building Minolta Co., Ltd. (72) Inventor Ryuji Kurita 5-2232-3-2-11-1 Sayama, Sayama City, Osaka, Osaka

Claims (3)

[Claims] A plurality of developer storage cells formed between the two substrates and having a predetermined gap therebetween, and one or more developer storage cells formed between the two substrates and surrounded by a partition wall; A dry developer encapsulated in a cell, wherein the dry developer has at least two types of dry developing particles having different charging polarities and different optical reflection densities, and having triboelectric charging properties. A method for producing a reversible image display medium, comprising: a first substrate preparing step of preparing a first substrate having a concave and convex shape including a concave portion for forming a developer accommodating cell; A developer accommodating step of accommodating the developer in a recess on one side of the first substrate; and a one side of the first substrate accommodating the developer in the recess so as to form a developer accommodating cell containing a developer. Second
A second substrate attaching step of attaching a substrate, wherein in the second substrate attaching step, the first and second substrates are brought into close contact with each other by reducing the pressure in the developer accommodating cell. A method for producing a reversible image display medium. 2. A method according to claim 1, further comprising: two substrates facing each other with a predetermined gap therebetween; one or more developer storage cells formed between the two substrates and surrounded by a partition wall; A dry developer encapsulated in a cell, wherein the dry developer has at least two types of dry developing particles having different charging polarities and different optical reflection densities, and having triboelectric charging properties. A method for producing a reversible image display medium, comprising: a first substrate preparing step of preparing a first substrate having a concave and convex shape including a concave portion for forming a developer accommodating cell; A developer accommodating step of accommodating the developer in a recess on one side of the first substrate; and a one side of the first substrate accommodating the developer in the recess so as to form a developer accommodating cell containing a developer. Second
And a second substrate attaching step of attaching a substrate. In the second substrate attaching step, the first and second substrates are bonded using a hot melt adhesive having an adhesiveness developing temperature lower than a softening temperature of the developer. A method for producing a reversible image display medium, comprising: bonding a substrate. 3. Two or more substrates facing each other at a predetermined gap, one or more developer storage cells formed between the two substrates, and surrounded by partition walls, A dry developer encapsulated in a cell, wherein the dry developer has at least two types of dry developing particles having different charging polarities and different optical reflection densities, and having triboelectric charging properties. A method for producing a reversible image display medium, comprising: a first substrate preparing step of preparing a first substrate having a concave and convex shape including a concave portion for forming a developer accommodating cell; A developer accommodating step of accommodating the developer in a recess on one side of the first substrate; and a one side of the first substrate accommodating the developer in the recess so as to form a developer accommodating cell containing a developer. Second
A second substrate attaching step of attaching a substrate, wherein in the second substrate attaching step, the first and second substrates are attached to each other using a reactive hot melt adhesive. Of producing a neutral image display medium.