JP2002350905A - Image display medium and image display method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the holding property of electrostatic latent image charges existing on a medium in displaying an image in an electric field-driven rewritable image display medium and to display the image in a stable state in which the image is hardly influenced by changes in ambient environment at a low cost while using a low voltage source. SOLUTION: This image display medium 1 includes a pair of substrates 11, 12, cells 16 which are formed between the substrates and image display materials which are hold in the cells and which can display an image by application of an electric field. Float electrodes 14 for forming the electric field are formed at least on one of the substrates.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an image display medium and an image display method.

[0002]

BACKGROUND OF THE INVENTION 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, an image display for displaying characters, figures, and the like on an image display medium such as paper using a pencil, a pen, or the like, a printer using an electrophotographic system, an ink spraying system, a thermal transfer system, etc. In the image display in which characters, graphics, and the like are displayed on an image display medium such as paper by an image forming apparatus such as an image forming machine or a facsimile machine, the images can be clearly displayed at a high resolution, and the images are easy for human eyes to see.

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.

For this reason, it replaces image display media such as paper.
Various rewritable image display media have been proposed.

A typical example is a pair of substrates facing each other with a predetermined gap, one or more cells formed between the substrates, and an image display material contained in each of the cells. An electric field drive type image display medium capable of displaying an image by applying an electric field corresponding to an image to the image display material.

Examples of this type of image display medium include a liquid crystal image display medium using the image display material as a liquid crystal material, an image display medium using the image display material as an electric field-driven dry developer, and An electrophoretic image display medium as a display liquid including particles having electrophoretic ability and a dispersion medium in which the particles are dispersed, and a capsule portion having particles capable of rotating the image display material by applying an electric field, and holding the dispersed therein capsule portions A twist ball type image display medium as a medium can be given.

In the rewritable electric field drive type image display medium described above, an electric field for image display must be applied to the image display material when displaying an image. Such an electric field or electrostatic field can be formed by various methods. For example, an electrostatic latent image corresponding to an image to be displayed is formed on one of the pair of substrates (for example, the substrate on the image observation side). Alternatively, it is conceivable to form an electrostatic latent image in close proximity to the electrostatic latent image based on the electrostatic latent image. Such an electrostatic latent image may be formed directly on the medium surface (substrate surface) using, for example, a direct electrostatic latent image forming apparatus, or formed outside the medium using an external electrostatic latent image forming apparatus. The electrostatic latent image may be transferred or brought close to the medium surface (substrate surface).

[0011]

An image is displayed on the image display medium in this manner. However, in the image display medium, the electrostatic latent image charge on the surface is hardly retained, and the image is disturbed in the display image. And the like are likely to occur.

When an image is displayed as a conductive substrate by providing a conductive layer on the outer surface of the medium substrate on the side opposite to the electrostatic latent image forming side for bias application (including grounding). The electrostatic latent image charge may leak from the conductive substrate to an operator who may touch a medium transport system or the like or an image display medium in the middle of being discharged, which may cause inconvenience such as disturbance of an image. May occur.

Regardless of which method is used to form an electrostatic latent image, the formation of the electrostatic latent image usually involves a discharge phenomenon, requiring a high voltage power supply for the discharge, and Since the discharge phenomenon is used, the formation of an electrostatic latent image is easily affected by fluctuations in the surrounding environment such as temperature and humidity, and there is also a problem that an obtained image is difficult to stabilize.

Accordingly, the present invention provides an electric field drive type rewritable image display medium and an image display method using the image display medium, wherein an image is displayed based on an electrostatic latent image corresponding to an image to be displayed. An object of the present invention is to provide an image display medium and an image display method that can improve the retention of electrostatic latent image charges on an image display medium and maintain a good image.

The present invention also relates to an electric field drive type rewritable image display medium and an image display method using the image display medium. The method uses a low-voltage power supply, is low-cost, and is stable without being affected by changes in the surrounding environment. It is an object to provide an image display medium and an image display method capable of displaying an image in a state where the image is displayed.

[0016]

The present invention provides the following image display medium and image display method. (1) Image display medium (1-1) First type image display medium A pair of substrates facing each other with a predetermined gap, one or more cells formed between the substrates, An image display medium capable of displaying an image by applying an electric field corresponding to an image to be displayed on the image display material, the image display medium comprising: a float for forming the electric field on at least one substrate; An image display medium in which electrodes are formed at a predetermined distribution density (in other words, resolution).

According to this image display medium, an electrostatic latent image charge is injected into a float electrode formed on the one substrate according to an image to be formed from an appropriate charge injection device, thereby displaying an image inside the medium. An image can be displayed by applying an electric field corresponding to the image to be formed on the material. In addition,
In displaying an image, a bias may be applied to the substrate on the side opposite to the charge injection side, if necessary (including grounding).

Since the electrostatic latent image can be formed by injecting the electric charge into the float electrode without using the discharge phenomenon, the electrostatic latent image charge on the image display medium is stably formed. The image is easily formed on the float electrode, and a good image is stably maintained.

Since the electrostatic latent image can be formed by injecting charges into the float electrode without using the discharge phenomenon, the electrostatic latent image can be formed at low cost by using a low voltage power supply. It is possible to form the image stably with little influence of the surrounding environment (mainly temperature and humidity), and to display a stable and good image at low cost. (1-2) Second type image display medium A pair of substrates facing each other with a predetermined gap, one or more cells formed between the substrates, and an image display material accommodated in each of the cells It is an image display medium capable of image display by applying an electric field according to the image to be displayed on the image display material, one of the substrates as a conductive substrate,
A float electrode layer for forming the electric field is formed on the conductive substrate, and when a predetermined pressing force is applied from the outside toward the conductive substrate, the float electrode layer has the conductive layer in the pressing region. Shows conductivity to conduct to the conductive substrate,
An image display medium, which is an anisotropic conductive layer showing an insulating property to the conductive substrate when the pressing force is released.

Examples of the conductive substrate include: (1) a substrate in which a conductive material is dispersed in an insulating material; and (2) an insulating layer and an outer surface of the insulating layer facing the float electrode layer. And a conductive layer formed on the substrate.

According to this image display medium, for example, an external electrostatic latent image forming apparatus (for example, an electrostatic latent image forming apparatus using an electrostatic latent image carrier such as a photosensitive member used in an electrophotographic image forming apparatus) An electrostatic latent image corresponding to an image to be formed outside the medium by using the apparatus, and transferring the electrostatic latent image to a substrate (substrate surface) opposite to the conductive substrate provided with the float electrode layer. The float electrode layer is locally connected to the conductive substrate by, for example, a pressing member for bias application (including grounding), and is adapted to an image to be formed on the image display material inside the medium. An image can be displayed by applying an electric field.

Each part of the float electrode layer is electrically connected to the conductive substrate only locally and temporarily for image formation, and is not connected to the conductive substrate except when locally pressed toward the conductive substrate. Shows insulating properties. Therefore, the electrostatic latent image charge on the medium is prevented from leaking from the conductive substrate to an operator who may touch the medium transport system or the like or the image display medium in the middle of being discharged. Image can be maintained.

For the first and second types of image display media, for example, a liquid crystal image display medium using the image display material as a liquid crystal material and an electric field drive type dry developer as the image display material are used. An image display medium, an electrophoretic image display medium in which the image display material is a display liquid including particles having electrophoretic ability and a dispersion medium in which the particles are dispersed, and the image display material is rotatable by applying an electric field. Any of a twist ball type image display medium as a holding medium in which a capsule portion having particles is dispersed may be used.

The liquid crystal image display medium controls the arrangement of liquid crystal molecules by applying an electric field to the liquid crystal, modulates external light incident on the liquid crystal, and displays a target image.

As an image display medium in which an image display material is an electric field driven dry developer, an image display medium introduced in "Japan Hardcopy '99 Transactions PP249-252" can be exemplified. In this medium, two substrates each having an electrode and a charge transport layer laminated thereon are opposed to each other at a predetermined interval to form a sealed space, in which a conductive toner and insulating particles of a different color are sealed. Then, 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.

In addition, the image display material is an electric field drive type dry developer, and the dry developers have different charging polarities.
In addition, an image display medium containing at least two types of dry-developed particles having triboelectricity, which have different optical reflection densities (in other words, "different contrast" or "different colors"), is also available. is there.

This image display medium can (1) repeatedly perform image display and image erasure. Therefore, use of conventional image display media such as paper, and consumables such as developer and ink related to image formation. (2) High-contrast, high-quality images can be displayed, (3) High-resolution, high-quality images can be displayed, There are advantages such as a low drive voltage for image display.

The electrophoretic image display medium is described in more detail. A sealed space is formed by arranging two substrates facing each other with a space therebetween via a spacer, in which particles having an 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.

As a twist ball type image display medium,
For example, an image display medium holding a large number of microcapsules in which microspheres treated so that a half of the surface and the other half exhibit different colors or optical densities together with the insulating liquid together with the insulating liquid therein is held. . In this medium, an image is displayed in a predetermined color by rotating microspheres in the microcapsules by electric field force or the like. (2) Image display method (2-1) First type image display method The image display medium according to (1-1) is used, and the float electrode is formed on the pair of substrates of the image display medium. An image display method including a step of injecting an electrostatic latent image charge according to an image to be formed on the float electrode of one substrate.

According to the first type of image display method, by using the image display medium described in the above (1-1), it is possible to improve the retention of electrostatic latent image charges on the image display medium and obtain a good image. Can be displayed and maintained.

Further, an image can be displayed at low cost by using a low-voltage power supply and in a stable state which is hardly influenced by changes in the surrounding environment.

The image display method of the first type is, for example, the same as that described in the above “(1) Image display medium”.
A liquid crystal image display medium using the image display material as a liquid crystal material,
An image display medium using the image display material as an electric field drive type dry developer, an electrophoretic image display medium using the image display material as a display liquid including particles having electrophoretic ability and a dispersion medium in which the particles are dispersed, Further, the present invention can be applied to a twist ball type image display medium in which the image display material is a holding medium in which capsule portions having particles rotatable by application of an electric field are dispersed.

As a further specific example of the image display method of the first type, the image display medium according to the above (1-1),
Preparing an image display medium in which the image display material is an electric field driven dry developer containing magnetic particles; and providing the float of one of the pair of substrates of the image display medium on which the float electrode is formed. An image including a step of injecting an electrostatic latent image charge according to an image to be formed on an electrode, and a step of applying a stirring force by a magnetic field to the dry developer simultaneously with and / or after the charge injection. A display method can be given.

The stirring force by the magnetic field may be applied before the charge injection.

According to this image display method, a stirring force by a magnetic field is applied to the dry developer simultaneously with and / or after the charge injection into the float electrode, so that the developer is applied for image formation. It is easy to move under an electric field, and an image can be displayed smoothly and with good contrast. (2-2) Second type image display method A step of preparing the image display medium according to (1-2),
Forming an electrostatic latent image corresponding to an image to be formed on an electrostatic latent image carrier, and applying the image display medium to the electrostatic substrate on the side opposite to the conductive substrate on which the float electrode layer is formed; The electrostatic latent image carrier is conveyed toward the latent image carrier while being brought into contact with the electrostatic latent image carrier, and a bias (including grounding) is caused by conducting a part of the float electrode layer to the conductive substrate by a bias applying pressing member. Applying the image.

According to the second type of image display method, by using the image display medium described in the above (1-2), it is possible to improve the holding property of the electrostatic latent image charge on the image display medium and obtain a good image. Can be displayed and maintained.

As for the second type of image display method, for example, a liquid crystal image display medium using the image display material as a liquid crystal material and the image display material similar to those described in the above “(1) Image display medium” , An image display medium using an electric field-driven dry developer, an electrophoretic image display medium using the image display material as a display liquid containing particles having electrophoretic ability and a dispersion medium in which the particles are dispersed, and the image display. The present invention can be applied to a twisting ball type image display medium as a holding medium in which a capsule material having particles rotatable by application of an electric field is dispersed.

As a further specific example of the image display method of the second type, the image display medium according to the above (1-2),
A step of preparing an image display medium, which is an electric field driven dry developer containing magnetic particles, and a step of forming an electrostatic latent image corresponding to an image to be formed on an electrostatic latent image carrier, The image display medium is transported toward the electrostatic latent image carrier on the opposite side of the conductive substrate on which the float electrode layer is formed, and on the upstream and downstream sides in the image display medium transport direction. Along with transporting the image display medium portion between the two members with the magnetic field stirring member and the bias application pressing member arranged in contact with the electrostatic latent image carrier,
Applying a bias (including grounding) by conducting a part of the float electrode layer to the conductive substrate by the bias applying pressing member.

According to this image display method, the stirring force of the magnetic field acts on the developer by the magnetic field stirring member to facilitate the movement of the developer, and the contact area between the medium and the electrostatic latent image carrier is widened. As a result, the application of an electric field for image formation to the developer is sufficient, and the magnetic field stirring force gradually decreases as the medium portion moves away from the magnetic field stirring member when viewed from each part of the image display medium.
Unnecessary developer agitation force is suppressed from acting on the developer forever, whereby images can be displayed smoothly and with good contrast.

[0040]

Embodiments of the present invention will be described below with reference to the drawings. <Image Display Medium of Dry Type Charged Particle Inclusion Type> (Regarding Image Display Medium shown in FIG. 1) FIG. 1 shows a schematic configuration of an example of an image display medium of an electric field drive type dry developer inclusion type.

The image display medium 1 shown in FIG. 1 has a pair of substrates 11 and 12 facing each other with a predetermined gap, one or more cells 16 formed between the substrates, Substrate 11 containing the dried electric field driven dry developer DL
Above is an image display medium on which float electrodes 14 for forming an electric field corresponding to an image to be formed are formed at a predetermined distribution density.

The medium 1 is a rectangular medium as a whole although its plan view is omitted.

Each of the first substrate 11 and the second substrate 12 is made of a transparent polyethylene terephthalate (PET) film having a thickness of 25 μm.

After a transparent ITO film is formed on the outer surface of the first substrate 11, this is etched to form a large number of minute float electrodes 14 with a predetermined distribution density (desired resolution). Here, each float electrode 14 is 20 μm.
Square electrodes with m squares, and the distance between adjacent electrodes is 10μ.
m. The float electrode may be formed by embedding conductive particles in the substrate.

On the outer surface of the second substrate 12, an aluminum deposited film 15 is formed as a conductive layer.

The inner surface of the first substrate 11 has a width of 50 μm.
m, a plurality of transparent PET band members having a height of 150 μm are attached to form a partition 13, and a predetermined amount of the developer DL is stored in each of the formed developer storage cells 16, and then the second substrate The image display medium 1 is formed by adhering the inner surface of 12 to the top of the partition 13.

Here, the developer DL is composed of white developing particles W
P and black developing particles BP. Without limitation, those details here are as follows: White developing particles WP 100 parts by weight of a thermoplastic polyester resin (softening point 121 ° C., glass transition point 67 ° C.), 40 parts by weight of titanium oxide (CR-50, manufactured by Ishihara Sangyo Co., Ltd.), and zinc salicylate as a negative charge control agent Complex (Orient Chemical: Bontron E)
-84) was sufficiently mixed with 5 parts by weight with a Henschel mixer, kneaded with a twin-screw extruder, and cooled. The kneaded material was coarsely pulverized, then pulverized by a jet pulverizer, and classified by air to obtain a white fine powder having a volume average particle size of 10.1 μm. Thereafter, 0.3 parts by weight of hydrophobic silica particles (manufactured by Nippon Aerosil Co., Ltd .: Aerosil R-972) were added, and the mixture was mixed with a Henschel mixer to obtain white developed particles WP. Black developing particles BP Styrene-n-butyl methacrylate resin (softening point 13
100 parts by weight at 2 ° C., glass transition point 65 ° C.) and carbon black (Ketjen Black E, manufactured by Lion Yushi Co., Ltd.)
C) and 4 parts by weight of silica (Nippon Aerosil Co., Ltd.
00) and 1.5 parts by weight of magnetite magnetic powder (RB).
-BL Titanium Industry Co., Ltd.) and 500 parts by weight with a Henschel mixer, and then kneaded with a vented biaxial kneader.

The kneaded product was cooled, coarsely pulverized by a feather mill, finely pulverized by a jet mill, and classified by an air classifier to obtain black particles BP having a volume average particle diameter of 25 μm. Developer DL The white particles WP and the black particles BP are placed in a polyethylene bottle at a ratio of 12 g of white particles and 88 g of black particles,
The mixture was stirred and mixed for 30 minutes while being rotated on a ball mill base to obtain a developer DL. The white particles were negatively charged and the black particles were positively charged. This developer DL was used.

In displaying an image, the image display medium 1 is conveyed along the medium conveyance path in the direction indicated by the arrow X in FIG. 1 while an electrostatic latent image charge corresponding to an image to be formed above the medium 1 is floated. The charge injection device 2 capable of injecting into the electrode 14 is disposed, and the charge injection needle 21 is brought into contact with the float electrode 14, and the medium 1 is placed facing the charge injection device 12.
The magnet plate 3 is arranged below the.

The charge injection device 2 has a predetermined resolution (for example, 6
(About 00 dpi) so that a large number of charge injection needles 2 can be injected in the direction perpendicular to the medium transport direction.
1 is arranged.

The magnet plate 3 has N poles and S poles alternately arranged along the medium transport direction X, and is reciprocated in parallel with the medium transport direction X by a driving device (not shown).

The conductive layer 15 of the medium substrate 12 is grounded.

Thus, while the white developing particles WP move to the float electrode 14 into which the positive charges have been injected, the black developing particles BP move to the float electrode 14 into which the negative charges have been injected, whereby a smooth image is formed. At this time, the image display surface is on the float electrode side using the transparent electrode, but the conductive layer 15 may be used as the image display surface by making the conductive layer 15 a transparent electrode layer. (Regarding the image display medium of FIG. 2) The image display medium 1 'of FIG. 2 differs from the medium 1 of FIG. Thus, a floating electrode 14 'is formed.
Other configurations are the same as those of the medium 1 in FIG. 1 are given the same reference numerals as in FIG.

In displaying an image, the image display medium 1 ′ is transported along the medium transport path in the direction of arrow X in FIG. 2, while the charge injection device 2 is applied to the float electrode 14 on the substrate 11 in the same manner as in FIG. And a rotatable roller electrode (here, a ground electrode) 41 is brought into contact with the float electrode 14 ′ on the lower substrate 12, and the roller electrode 41 is contacted clockwise or counterclockwise in the drawing, or the reciprocating direction thereof. Has a built-in magnet roller 42 that is driven to rotate by a drive device (not shown). The roller electrode 41 and the magnet roller 42 are arranged to face the charge injection needle 21 of the charge injection device 2.

Thus, an image is smoothly formed as in the case of the medium 1 shown in FIG.

According to the medium 1, the electric charge injected into the float electrode 14 is easily held there, and the medium 1 '
According to this, the electric charge injected into the float electrode 14 and the electric charge of the float electrode 14 'are easily held there, and a good image is stably maintained accordingly. In addition, a low voltage power supply is sufficient as a power supply for the charge injection device 2, and an image can be formed at a low cost. In addition, since charge injection is used, an image can be stably formed with little influence of the surrounding environment (mainly temperature and humidity). The image is formed by applying a magnetic field stirring force to the developer DL in the medium by the magnet plate 3 for the medium 1 and the magnet roller 42 for the medium 1 ', so that the image can be formed smoothly.

In order to suppress the occurrence of image disturbance or the like due to electric leakage, the entire medium 1 or the floating electrode 14, or the floating electrode 14, 14 ', or the like, at which there is a possibility of electric leakage after image formation is insulated. It may be covered with a film. (Regarding Image Display Medium in FIG. 3) Image Display Medium 5 in FIG.
Is the float electrode 1 on the substrate 11 in the medium 1 of FIG.
4 is not provided, and a float electrode layer (anisotropic conductive layer) 17 is provided on the conductive layer 15 of the substrate 12. Otherwise, it has the same configuration as the medium 1 in FIG. 1 are given the same reference numerals as in FIG.

Although the float electrode layer 17 is not limited to this, it is formed here as follows. That is, as illustrated in FIG. 4, an inner diameter 1 for filling an insulating sheet 171 such as a resin sheet or a rubber sheet with a conductive material is used.
The center distance between adjacent through holes 172 is about 3 mm.
mm, and formed in a zigzag pattern as a whole. In each through-hole 172, liquid silicon rubber, liquid epoxy resin, liquid urethane resin, liquid phenol resin, hot-melt resin, solvent-soluble resin, etc. A conductive material in which a conductive material such as aluminum nitride, boron carbide, graphite, aluminum oxide, and various metal particles is dispersed is filled and cured to form a conductive portion 173. Further, for example, a screen is provided on one surface of the insulating sheet 171 An insulating material projection 174 that can be deformed under pressure as a spacer by printing or the like is formed, and is adhered to the substrate conductive layer 15 with the projection 174.

In FIG. 4, reference numeral 13 denotes a partition wall of the medium 5 and the distance between the walls is exemplified as 10 mm.

An image can be formed on the image display medium 5 using, for example, an external electrostatic latent image forming apparatus as shown in FIG.

The external electrostatic latent image forming device 6 shown in FIG. 5 is a photosensitive drum PC which is driven to rotate in the direction of arrow CCW in the figure.
And a charging device C sequentially disposed around the photosensitive drum
H and an image exposing device EX.

Here, the surface of the photosensitive drum PC is charged to about -900 [V] by the charging device CH, and the charged area is image-exposed by the image exposing device EX to form an electrostatic latent image corresponding to an image to be formed. Is formed on the surface of the drum PC, and can be conveyed to the image forming area Z.

The image forming area Z is an area through which the medium 5 passes, and in this area, a magnet roller 7 and a bias application pressing roller 8 located on the upstream side and the downstream side in the medium conveying path are arranged. Magnet roller 7
Is built in a rotatable roller 70, and is rotationally driven by a driving device (not shown). These rollers 70 and 8
Is opposed to the photosensitive drum PC with a gap through which the medium 5 passes. At the time of displaying an image, the roller 8 is supplied with -4 from the power supply Vb.
A bias voltage of 50 [V] is applied. The roller 8 is driven to rotate in the medium transport direction by a drive device (not shown), and also serves as a transport roller.

In forming an image on the medium 5, the medium 5 is transported in the direction of arrow X in FIG. 5 with the substrate 11 on which the float electrode layer 17 is not formed facing the photosensitive drum PC. It is fed into the image forming area Z in synchronization with the electrostatic latent image formed thereon. The medium 5 passes between the photosensitive drum PC and the roller 70, and the photosensitive drum PC
It is curved by the surface, passes between the next roller 8 and the photosensitive drum PC while contacting the surface of the photosensitive drum PC, and is released thereafter. Thus, an image is formed.

In forming the image, the roller 70 applies the conductive portion 173 of the float electrode layer 17 to the substrate 12.
The medium 5 is pressed against the photosensitive drum PC to such an extent that the medium 5 is not brought into contact with the upper conductive layer 15.
Disposes the medium 5 so that the float electrode layer 17 and the protrusion 174 are locally deformed in a region where the roller 8 contacts, and the conductive portion 173 in that region is brought into contact with the conductive layer 15 of the substrate 12. It is pressed against the photosensitive drum PC. FIG. 6 shows this state. In FIG. 6, illustration of the developer DL in the medium 5 is omitted. Press roller 8
As a result, the conductive portion 173 pressed against the conductive layer 15 comes into contact with the conductive layer 15. As a result, a bias for image formation is applied from the power supply Vb to the entire conductive layer 15 of the medium 5 via the roller 8.

In this manner, an image can be displayed by applying an electric field corresponding to an image to be formed on the medium 5 based on the electrostatic latent image on the photosensitive drum PC.

As described above, in the image formation, each part of the float electrode layer 17 is electrically connected to the conductive layer 15 only locally and temporarily for image formation.
Except when it is locally pressed toward the conductive layer 15, the conductive layer 15 is insulative. Therefore, the leakage of the electrostatic latent image charge on the medium 5 from the conductive layer 15 to the medium transport system or the like or an operator who may touch the image display medium being discharged is suppressed, A good image can be maintained accordingly. After the image is formed, the float electrode layer 17 is in a state of being insulative to the conductive layer 15, so that a good image can be maintained in this regard.

In the image formation described above, the stirring force of the magnetic field acts on the developer DL by the magnet roller 7 to facilitate the movement of the developer, and the contact area between the medium 5 and the photosensitive drum PC is widened. Accordingly, the application of an electric field for image formation to the developer DL is sufficient, and the magnetic field agitation force of each part of the medium gradually decreases as the medium part moves away from the magnet roller 7, so that unnecessary development is not performed. It is possible to prevent the developer stirring force from acting on the developer DL forever, thereby forming an image smoothly and with good contrast.

When the developer DL does not contain magnetic particles, the magnet roller 7 can be replaced with a simple roller or can be omitted. <Electrophoretic Image Display Medium> FIG. 7 shows a structural example of an electrophoretic image display medium 1400.

The medium 1400 shown in FIG. 7 has an electric field coloring layer 140 supported on a transparent support substrate 146. The electric field coloring layer 140 converts the charged coloring particles 141 into the insulating liquid 14.
2, a developer 143 dispersed in the transparent conductive layer 144 and the insulating substrate 145 are sealed. Substrate 145
Has a floating electrode P1 with a predetermined distribution density. A high-purity petroleum (for example, Isopar (trade name, manufactured by Esso Corporation)) is used as the insulating liquid 142. The insulating liquid 142 contains an ionic surfactant and a dye, and organic particles 141 are mixed to form a developer 143. The ionic surfactant is adsorbed on the pigmented organic coloring particles 141 and the particles are electrochemically stably charged. The charged colored particles 14
1 is dispersed in the liquid 142 and exhibits electrophoretic properties.

When no electric field is applied to the medium 1400 or when an electric field opposite to a predetermined electric field is applied, the color of the dye in the insulating liquid 142 is visible, but an electrostatic latent image is written. And the charged colored particles 141 form the transparent conductive layer 14.
Moving toward 4, the pigment is visible.

This medium 1400 is the insulating liquid 1 in the medium.
An image can be displayed by forming an electrostatic field corresponding to the image to be displayed on the charged developing particles (here, charged colored particles) 141 dispersed in 42.

The electric or electric field is, for example, the medium 1 shown in FIG.
In the same manner as described above, it can be formed by injecting an electrostatic latent image charge into the float electrode P1. <Twistball-Type Image Display Medium> FIG. 8 shows a structural example of a twistball-type image display medium 1500.

The medium 1500 shown in FIG. 8 has an electric field coloring layer 150 supported on a transparent support substrate 156. The electric field coloring layer 150 surrounds a single-sided colored sphere 151 colored on one side 151a with an insulating liquid 152 so as to float therein.
The liquid is embedded in an insulating holding medium 153 and the medium 1
53, a transparent conductive layer 154 is formed on one side and an insulating substrate 155 is formed on the other side. On the substrate 155, the floating electrodes P2 are formed with a predetermined distribution density.

The single-sided colored sphere 151 is produced, for example, by uniformly disposing a white sphere of glass mainly composed of TiO ₂ on a suitable table and depositing chromium or the like from the upper surface. The size may be in the range of 30 μm to 100 μm, but 10 μm
If the following is set, the resolution will be higher.

The single-sided colored spheres 151 are dispersed in, for example, an insulating holding medium 153 such as an elastomer, and the medium 153 is immersed in a solution in which an ionic surfactant is dissolved in an organic solvent such as toluene. Swell, thereby causing the insulating liquid 152 to collect around the single-sided colored sphere 151. Thus, the single-sided colored sphere 151 is made of the insulating liquid layer 15.
2, the liquid is embedded in the insulating holding medium 153 together with the liquid in a rotatable state.

Since the one-sided colored sphere 151 has different properties on one hemisphere and the other hemisphere, the amount of adsorbed ions is different on both surfaces. Therefore, when an electric field is applied to the medium 15, the direction of the surface of the single-sided colored particles 151 changes depending on the direction of the electric field. Accordingly, an image is displayed by seeing the colored surface of the single-sided colored sphere 151 or an uncolored surface.

In displaying an image, for example, the medium 1 shown in FIG.
In the same manner as described above, it can be formed by injecting an electrostatic latent image charge into the float electrode P2.

Although illustration is omitted, the liquid crystal image display medium described above or “Japan Hardcopy '99 Transactions PP249-252”
The above-mentioned image display medium introduced in the above-mentioned is also provided with a float electrode in the same manner as the medium shown in FIG. 1 or FIG. 2, or by providing a float electrode layer in the same manner as the medium shown in FIG. It is also possible to form an image in the same way as with the medium 5 and the medium 5.

[0080]

As described above, according to the present invention, there are provided an electric field drive type rewritable image display medium and an image display method using the image display medium, wherein an electrostatic latent image corresponding to an image to be displayed is formed. In displaying an image based on the above, it is possible to provide an image display medium and an image display method that can improve the retention of electrostatic latent image charges on the image display medium and maintain a good image accordingly.

Further, according to the present invention, there is provided an electric field drive type rewritable image display medium and an image display method using the image display medium, which are low-cost using a low-voltage power supply and are hardly influenced by ambient environmental fluctuations. An image display medium and an image display method capable of displaying an image in a stable state can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of an image display medium according to the present invention and an image display method using the same.

FIG. 2 is a diagram showing another example of the image display medium according to the present invention and an image display method using the same.

FIG. 3 is a diagram showing still another example of the image display medium according to the present invention.

FIG. 4 is a diagram showing an example of distribution of conductive portions of a float electrode layer in the image display medium of FIG. 3;

5 is a diagram showing an image display method using the image display medium shown in FIG.

6 is a diagram showing a deformation state of a float electrode layer of an image display medium in the image display shown in FIG.

FIG. 7 is a diagram showing still another example of the image display medium according to the present invention.

FIG. 8 is a diagram showing still another example of the image display medium according to the present invention.

[Explanation of symbols]

 1, 1 ', 5 Dry-type charged particle-encapsulated image display medium> 11 First substrate 12 Second substrate 13 Partition wall 15 Conductive layer (aluminum deposited film) 16 Developer storage cell 14, 14' Float electrode DL Electric field drive type Dry developer WP White developing particles BP Black developing particles 2 Charge injection device 21 Charge injection needle 3 Magnet plate 41 Roller electrode 42 Magnet roller 17 Float electrode layer (anisotropic conductive layer) 171 Insulating sheet 172 Through hole 173 Conductive part 174 Insulating material projection 6 External electrostatic latent image forming device PC Photoreceptor drum CH charging device EX Image exposing device Z Image forming area 70 Roller 7 Magnet roller 8 Bias applying pressing roller Vb Bias power supply 1400 Electrophoretic image display medium 140 Electric field coloring layer 141 Charged colored particles 142 Insulating liquid 143 Developer 144 Transparent conductive layer 145 Insulating substrate 146 Transparent support substrate P1 Float electrode 1500 Twist ball type image display medium 150 Electric field coloring layer 151 One side 151a Colored sphere 152 Insulating liquid 153 Insulating holding medium 154 Transparent conductive layer 155 Insulating substrate 156 Transparent Support substrate P2 Float electrode

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G09G 3/36 G09G 3/36

Claims (11)

[Claims] An image display device comprising: a pair of substrates facing each other with a predetermined gap therebetween; one or more cells formed between the substrates; and an image display material accommodated in each of the cells. An image display medium capable of displaying an image by applying an electric field corresponding to an image to be displayed on a material, wherein a float electrode for forming the electric field is formed on at least one substrate with a predetermined distribution density. Characteristic image display medium. 2. An image display comprising: a pair of substrates facing each other with a predetermined gap therebetween; one or more cells formed between the substrates; and an image display material accommodated in each of the cells. An image display medium capable of displaying an image by applying an electric field corresponding to an image to be displayed on a material, wherein one of the substrates is a conductive substrate, and a float electrode layer for forming the electric field is formed on the conductive substrate. The float electrode layer is formed, and when a predetermined pressing force is applied from the outside toward the conductive substrate, the floating electrode layer exhibits conductivity to be conducted to the conductive substrate in the pressing region, and the pressing force is released. The image display medium is an anisotropic conductive layer having an insulating property with respect to the conductive substrate. 3. The image display medium according to claim 2, wherein the conductive substrate is a substrate including an insulating layer and a conductive layer formed on an outer surface of the insulating layer facing the float electrode layer. . 4. A liquid crystal image display medium using the image display material as a liquid crystal material, an image display medium using the image display material as an electric field drive type dry developer, and electrophoretic particles of the image display material. An electrophoretic image display medium as a display liquid containing a dispersion medium dispersed therein, and a twist ball as a holding medium in which a capsule portion having image display particles rotatable by applying an electric field is dispersed in the image display material. 4. The image display medium according to claim 1, wherein the image display medium is one of a type image display medium. 5. The image display material is an electric field driven dry developer, wherein the dry developer has at least two kinds of dry-type triboelectrically-chargeable toners having different charging polarities and different optical reflection densities. 4. The image display medium according to claim 1, comprising a developing particle. 6. An image display medium according to claim 1, wherein said one of said pair of substrates of said image display medium has a static electrode according to an image to be formed on said float electrode on one of said substrates on which said float electrode is formed. An image display method comprising a step of injecting an electrostatic latent image charge. 7. The image display medium, a liquid crystal image display medium using the image display material as a liquid crystal material, an image display medium using the image display material as an electric field driven dry developer, and an electrophoretic device using the image display material. Electrophoretic image display medium as a display liquid containing particles having particles and a dispersion medium in which the particles are dispersed, and a capsule portion having image display particles rotatable by applying an electric field to the image display material. 7. The image display method according to claim 6, wherein the holding medium is any one of a twisted ball type image display medium. 8. The image display medium according to claim 1, wherein said image display material is an electric field drive type dry developer containing magnetic particles, and said pair of said image display media is provided. Injecting an electrostatic latent image charge according to an image to be formed on the float electrode of one of the substrates on which the float electrode is formed, and simultaneously or (and) after the charge injection Applying a stirring force by a magnetic field to the dry developer. 9. A step of preparing the image display medium according to claim 2 or 3, a step of forming an electrostatic latent image corresponding to an image to be formed on an electrostatic latent image carrier, and A substrate opposite to the conductive substrate on which the float electrode layer is formed is conveyed toward the electrostatic latent image carrier while being in contact with the electrostatic latent image carrier, and the float is pressed by a bias applying pressing member. Applying a bias by conducting a part of the electrode layer to the conductive substrate. 10. The image display medium, a liquid crystal image display medium using the image display material as a liquid crystal material, an image display medium using the image display material as an electric field-driven dry developer, and an electrophoretic device using the image display material. Electrophoretic image display medium as a display liquid containing particles having particles and a dispersion medium in which the particles are dispersed, and a capsule portion having image display particles rotatable by applying an electric field to the image display material. The image display method according to claim 9, which is any one of a twisted ball type image display medium serving as a holding medium. 11. An image display medium according to claim 2 or 3, wherein said image display material is an electric field driven dry developer containing magnetic particles, and a step of preparing an image display medium. Forming a corresponding electrostatic latent image on the electrostatic latent image carrier; and forming the image display medium on the opposite side of the conductive substrate on which the float electrode layer is formed on the electrostatic latent image carrier. And a bias applying pressing member disposed on the upstream side and the downstream side in the image display medium conveying direction, and the image display medium portion between the two members is carried by the electrostatic latent image holding member. Transporting the body while making contact with the body, and applying a bias by conducting a part of the float electrode layer to the conductive substrate by the bias applying / pressing member.