JPS60217383A - Image display unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an image forming powder (hereinafter referred to as toner) that applies an electric charge to one side of an image display device, particularly a recording medium, in response to an image signal, and has magnetism and conductivity to the opposite side. The present invention relates to an image display device that forms and displays a visible image by giving

Conventionally, this type of image forming method is generally known as a contrast method. This uses a film with high resistance as a recording medium, and a recording electrode is placed on the back side of the film, and a developing device with conductive magnetic toner is placed on the surface. Toner is applied to a recording medium to make it visible by applying a recording signal to the recording medium.

This image forming method will be explained with reference to FIG.

In FIG. 1, reference numeral 1 denotes a recording medium, and recording electrodes 2 made up of a large number of needle electrodes arranged side by side are arranged on the back surface of the recording medium with a small gap therebetween. A signal voltage corresponding to an image pattern is independently applied to each needle electrode of the recording electrode 2 by a character signal generator 3. A developing device 4 is disposed facing the recording electrode 2. The developing device A includes conductive magnetic toner T and a sleeve 5 made of a hollow cylinder made of a non-magnetic conductor. It has a magnet 6 fixed within the sleeve 5, and these are housed in a toner holder.

The recording medium 1 moves in the direction of arrow A, and the character signal generator 3 applies a recording voltage to the recording electrode 2 according to the multi-image pattern. The sleeve 5 is rotated in the direction of arrow B, whereby the toner T is conveyed on the sleeve by the action of the magnet and stone 6, and when it comes into contact with the recording medium 1, this toner T becomes the opposite electrode of the recording electrode 2, and the recording voltage is applied. A discharge occurs between the recording medium 1 and the tip of the recording electrode 2 to which is applied, and at the same time an electric charge is generated on the back surface of the recording medium 1, the toner is passed from the sleeve 5 to the recording medium 1.
-, a charge of opposite polarity to the charge is injected into the toner T, and due to the attractive force between the charge of the toner and the charge on the back surface of the recording medium, the toner T resists the magnetic force of the magnet 6 and reaches the surface of the recording medium. A visible image is obtained. Such an image forming method has a problem in that a minute gap (several μm to several tens of μm) must be created between the recording electrode 2 and the recording medium 1. 57-105
There is also a method of roughening the surface of the recording medium 1 as described in No. 758.

However, in such a method, since the thickness of the recording medium 1 governs the resolution, it must normally be as thin as 10 to 30 microns. However, there are many difficulties in circulating and transporting such films. Furthermore, since a conductive layer is not laminated on the recording medium, it is difficult to uniformly erase the latent image, and even if an attempt is made to clean the previous image, it is still difficult because a large force cannot be applied to the thin recording medium.

As an improved version of such an image forming method, the method described with reference to FIG. 2 has been proposed.

In FIG. 2, parts similar to those shown in FIG. 1 are designated by the same reference numerals.

In the image forming method shown in FIG. 2, a charge applying means generally indicated by 2' is provided in place of the recording electrode 2 shown in FIG. The charge donor, stage 2', is connected to the first electrode 8.
Second electrode9. Third electrode 10. A first dielectric 11 insulating these electrodes. It is made of the second dielectric 12 and extends in a direction perpendicular to the moving direction of the recording medium 1 (width direction). Second electrode9. Second dielectric 12. The third electrode 10 is penetrated by a large number of openings 13 arranged in the width direction. Second. A signal voltage is applied to each electrode 9 from the character signal generator 3 independently by the number of openings 13. When an AC voltage is applied between the first electrode 8 and the second electrode 9 from the AC power supply 14, the first dielectric 1
Corona discharge occurs between the electrode 1 and the second electrode 9, and positive ions and negative ions are generated inside the opening 13. At this time, the second electrode 9. If a potential gradient is created between the third electrode 10° and the sleeve 5, ions will adhere to the recording medium 1. These processes are described in Japanese Unexamined Patent Application Publication No. 1973-
78134.

(5) Charges of opposite polarity to the charged particles (ions) attached to the back surface of the recording medium 1 are applied to the toner T that comes into contact with the surface of the recording medium through the sleeve 5, and the toner adheres to the surface of the recording medium 1. Produces a visible image. This point is explained in the first section.
Same as the description of the figure.

Conversely, when removing the adhered toner T from the recording medium, the charge on the back surface of the recording medium 1 is eliminated (electrostatic discharge).
There is a need. In this case, it is necessary to eliminate static electricity while grounding the surface of the recording medium, but in the apparatus shown in Fig. 2, the charge applying means 2' can be used to eliminate static electricity from the back surface of the recording medium, and at the same time The surface of the body 1 is automatically grounded, and the toner adhering to the surface is also removed. Note that it is also possible to use a static eliminator separate from the charge applying means 2', and in this case, it is preferable to switch the positions of the charge applying means 2' and the static eliminator only when erasing an image. When the charge applying means 2' is used for the purpose of static elimination, the second electrode 9. Third electrode 10. If the sleeve 5 is made to have the same potential, out of the positive ions or negative ions in the opening 13,
Ions of opposite polarity to the charge on the back surface of the recording medium 1 (6) are attracted to the charge, and the back surface of the recording medium 1 is neutralized, and at the same time, the charge held by the toner on the surface of the recording electrode 1 is also removed from the sleeve. Returning to , there is no longer any adhesion between the recording medium 1 and the toner, and the toner T is attracted to the magnet 6 and collected into the toner hopper T.

The recording medium 1 is a dielectric film such as polyester, polyethylene, f! It is desirable to use a material such as vinyl chloride that has a resistance value equal to or higher than that of a 100-sub-plate and has high tensile strength. The thickness may be 1 μm to 100 μm, but it is desirable to be thin in order to increase resolution, and thick in order to increase tensile strength. In addition, in order to make the recording medium white for reflective display, a white pigment is mixed in before film formation.
Alternatively, a mixture of white pigment and binder resin may be applied to the surface. In the experimental example, polyester having a thickness of 25 μm was used.

The thickness of the first dielectric 11 is related to the output voltage of the AC power supply 14, and the thinner the first dielectric 11, the lower the applied voltage. In the experimental example, mica with a thickness of 20 μm was used. First electrode8. Second electrode9. Third electrode 1
0 uses 20 μm thick stainless steel foil, and the second
Although the dielectric 12 is related to the diameter of the opening 13, in the experimental example, a dielectric 12 having a thickness of 100 μm was used, and the diameter of the opening 13 was 130 μm. The apertures 13 are usually arranged in a line perpendicular to the direction of movement of the recording medium 1, and the second electrode 9 can independently control the voltage as many as the number of apertures 13. but,
Normally, in order to increase the recording density, the apertures 13 are staggered or arranged diagonally in several rows, and the combination of the first electrode 8 and the second electrode 9 is arranged in a matrix shape, forming intersections and driving them separately. Good too.

The distance between the third electrode 10 and the recording medium 1 was set to 0.2 ttan.

The sleeve 5 facing the recording electrode 2 is made of stainless steel and has a diameter of 2.
The internal magnetic force 6 had four poles magnetized evenly and the magnetic flux density on the sleeve surface was 460 Gauss. The sleeve is rotated in the direction of arrow B at 64 revolutions per minute by a drive source (not shown). The gap between the recording medium '1 and the sleeve is set to 0.5 mm, and a non-magnetic doctor blade 15 is attached to the toner hole AI-L7 to uniformly apply toner.

The toner T may be a conductive magnetic toner having a resistance value of 1010 Ω on a sub-plate, and 3M Company's 355 Imaging No+Wooder was used.

With the above configuration, the recording medium was moved in the direction of arrow A at a speed of 180 m/s, the frequency was 500 kHz, and the applied voltage was 2.
．． 5 kV vp-p is applied to the first electrode 8 from the AC power source 14.
．． A voltage of -700V is applied to the second electrode 9 when there is an image signal from the character signal generator 3, and a voltage of -400V is applied when there is no image signal. The third electrode 10 is connected to the DC power supply 16! D-600V is constantly applied. In this state, when the character signal generator 3 supplies a recording signal corresponding to the shoal pattern □ as explained in FIG. 2, negative ions adhere to the recording medium 2. At this time, positive charges are injected into the toner T on the opposite side from the surface of the sleeve 5, the negative ions adhering to the recording medium 1 and the toner T attract each other, and the toner T adheres to the recording medium 1. When there is no recording signal, the second electrode 9 is maintained at -300V, and the second electrode 9 and the third electrode 10 inside the aperture 13 create a reverse electric field that does not allow ions (9) to pass through. Since ions do not adhere to 1, toner T does not adhere to it. When this is done continuously, a visible image appears on the recording medium 1. On the other hand, when removing the toner T adhering to the recording medium 1, the first electrode 8. An AC voltage is applied to the second electrode 9 from the AC power source 14, and the second electrode 9. By grounding the third electrode 10 and the sleeve 5, the ions obtained by AC corona discharge between the first electrode 8 and the second electrode 9 are attracted by ions of opposite polarity due to the charge attached to the recording medium 1. Hole. In this experiment, since the recording medium 1 is negatively charged, positive ions are attracted to it, and these cancel each other out, causing the charge on the recording medium 1 to disappear. At the same time, the charges injected into the toner T flow into the sleeve 5, so that no adhesion force is generated between the recording medium 1 and the toner T. This toner T is collected by the toner hole /4'-7 by the magnetic force generated by the magnet 6. Also, as mentioned above, the second electrode 9. Although the explanation has been given in which the third electrode 10 is grounded, an AC voltage having the same phase as the AC (10) power source 13 may be applied to the second electrode. However, in this case, it is better to increase the voltage of the AC power supply 13.

In the above-described image forming method, the recording medium must be thin, but when a thin film is used as the recording medium, defects such as film misalignment and wrinkles occur, making it difficult to obtain stable image display. Further, especially in the method shown in FIG. 1, it is difficult to erase the image.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image display device that eliminates the above-mentioned drawbacks, has a simple configuration, can display images stably, and can also erase images conveniently.

An image display device according to the present invention applies a charge corresponding to an image signal to one side of an insulating or high-resistance recording medium, and applies image forming powder to the opposite side to form and display a visible image. , having an image forming position where image forming powder is applied to form a visible image, and an image display position where the recording medium on which the image is formed is stopped and the visible image is displayed,
The present invention is characterized in that winding means capable of reciprocatingly winding the recording medium are provided at both ends of the recording medium.

FIG. 3 shows an embodiment of the invention.

The image recording medium 17 is mounted on a guide roller 2 with a first winding roller 18 and a second winding roller 19 at both ends.
0.21.22 so that it can reciprocate in both directions. In the figure, A indicates an image forming position where a visible image is formed using toner, and B indicates an image display position where the recording medium is stopped and the visible image is displayed. During image formation, it is driven in the direction of the arrow 24, and the charge applying means 2' and the developing device 4 explained in FIG.
The toner image is formed by passing through the image forming position A, which is configured as follows. At image display position B, recording medium 1, which is a thin film, is placed.
A back plate 23 is provided for holding 7 flat. This has a surface with a low coefficient of friction or contacts with very low force so as not to damage the recording medium 17. Image Display At position B, the recording medium 17 on which the necessary screen has been formed is stopped and used for display.

After the display is finished, the recording medium 17 is driven in the direction of the arrow 25, and unnecessary images are erased by the image recording means. The film after the toner image has been erased heads toward the first winding roller 18, but it is difficult to completely erase the toner image microscopically, and if the toner image erased surface is wound up, the recording medium will not last for a long time. 1
The toner is attached to the charge-applying surface of No. 7. Therefore, it is desirable that the length of the recording medium 17 from the first winding sheet roller to the image recording position be equal to the length of the displayed image.

Although not shown, the visible image obtained on the recording medium may be transferred to another recording paper using pressure transfer, heat transfer, corona transfer, etc., or if the recording medium 1 is transparent. If this is the case, we can make it possible to irradiate light with it fixed or unfixed by heating, and create a projection display that can function as an overhead flow projector.
It can also be used as Further, as the image forming means on the recording medium, the method described in FIG. 2 is suitable, but the method described in FIG. 1 and other ion flow modulation methods can also be applied.

(13) Conventionally, this type of image display device has been configured such that the film is made into an endless shape and is rotated by a plurality of rollers. The film position shifts to one side or the other due to the difference in position, and this shift accumulates over time of rotation. Therefore, it is necessary to provide a □ lateral deviation prevention mechanism to restore this deviation, but if such a lateral deviation prevention mechanism is activated, it will cause wrinkles. However, since the apparatus of the present invention is configured so that the film moves back and forth, the deviations that occur during the forward movement are returned to their original positions during the backward movement, and the deviations do not accumulate. Therefore, according to the configuration of the present invention, even when a thin film is used as a recording medium, misalignment of the film, occurrence of wrinkles, etc. can be prevented, and a stable image display device can be realized. Furthermore, since images can be erased when the recording medium is moved back, a device with a very simple configuration can be realized.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an example of a conventional image forming method, (14
) FIG. 2 is an explanatory diagram showing another example of the image forming method, and FIG. 3 is a diagram showing an embodiment of the image display device according to the present invention. DESCRIPTION OF SYMBOLS 1... Recording medium, 2... Recording electrode, 2'... Charge applying means, 3... Character signal generator, 5... Sleeve, 6... Magnet, 7... Hopper, 8...first electrode, 9...second electrode
electrode, 10... third electrode, 11... first dielectric,
12... Second dielectric, 13... Opening, 14...
・AC power supply, 15...Doctor blade, 16...DC power supply, 17...Recording medium, 18...
- First winding roller, 19... Second winding roller, 20.21.22... Guide roller, 23... Back plate. (15) Figure 1, (1 in Figure 2 Figure 3 ■ 10) 43 Lβ1

Claims (3)

[Claims] (1) In an image display device that applies a charge corresponding to an image signal to one side of an insulating or high-resistance recording medium and applies image-forming powder to the opposite side to form and display a visible image,
It has an image forming position where image forming powder is applied to form a visible image, and an image display position where the recording medium on which the image has been formed is stopped and the visible image is displayed. 1. An image display device comprising a winding means capable of movably winding the image. (2) The image display device according to claim (1), wherein the image is erased at the image forming position when the recording medium is moved backward. (3) The means for applying a charge corresponding to the image signal is the first,
Second. The first electrode has a third electrode. An AC voltage is applied between the second electrodes, an image signal is applied to the second electrode, and a DC voltage is applied to the third electrode. The image display device according to claim (1), wherein an AC voltage is applied between the second electrodes, the third electrode is grounded, and the second electrode is grounded or applies an AC voltage having the same phase as the first electrode. .