JPH11212501A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a satisfactory image in a short time. SOLUTION: Plural ITO electrodes 4, 4N, 5 and 5N are respectively arranged on the front side and the rear side of a color developing sheet where many black and white bicolor rotating globular particles 1 are rotatably stored in a planar state. When black faces of bicolor rotating globular particles 1 are directed to the front side of the color developing sheet, a positive voltage pulse having the polarity opposite to that of a negative voltage pulse 7 is applied just before the negative voltage pulse 7 to direct the black faces to the front side of the color developing sheet is applied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly, to an image forming apparatus that forms an image using a plurality of rotating bodies each of which is painted in two colors.

[0002]

2. Description of the Related Art Conventionally, half of a sphere is divided into two colors, such as white and the other half is black, and rotating sphere particles having different surface charges in an electric field are converted into a sheet-like elastomer such as silicone resin. A display device which is laid inside and forms an image by selective rotation of these two-color rotating spherical particles is disclosed by Xerox Corporation in, for example, U.S. Pat. No. 4,143,103. The method of driving these rotating spherical particles, which is introduced in the present invention, uses a sheet on which the rotating spherical particles are arranged,
There is suggested a driving method in which the electrodes are arranged between electrodes arranged in parallel in the vertical direction and an electric field generated by these electrodes is used.

[0003]

In a display using such two-color rotating sphere particles, experiments conducted by the present inventors have shown that the two-color rotating sphere particles do not rotate with high accuracy in the conventional method, or that two-color rotating spherical particles do not rotate. It was found that the application speed of the rotating sphere particles was low, and that an image could not be formed in a short time.

In the above experiment, it has been found that halftone display cannot be performed because the threshold characteristics of the two-color rotating spherical particles in the rotating operation are uniform.

Further, in the above experiment, it was found that the two-color rotating sphere particles in the non-selected state slightly rotated, and a good image could not be obtained.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to propose an image forming apparatus capable of forming a good image in a short time and capable of displaying a density gradation.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention comprises a first surface of a first color and a second surface of a second color different from the first color. A first surface and the second
A plurality of rotating bodies having electric charges or magnetic charges having different sizes from each other, a sheet accommodating the plurality of rotating bodies so as to be rotatable in a planar shape, and a predetermined area in the sheet for forming an image Applying means for selectively applying an electric field or a magnetic field for directing the first surface or the second surface to the surface of the sheet based on the image data, to a plurality of rotating bodies disposed in The image forming apparatus, wherein the applying unit is configured to direct the first surface or the second surface of the rotator disposed in the region to the sheet surface, and to apply the first surface or the second surface to the sheet surface. Immediately before applying the first electric field or magnetic field for directing the second surface to the surface of the sheet, a second electric field or magnetic field having a polarity opposite to that of the first electric field or magnetic field is applied.

That is, each of the plurality of rotating bodies according to the present invention comprises:
A charge or magnetic field having a first surface of a first color and a second surface of a second color different from the first color and having different sizes on the first surface and the second surface; Have a load. It should be noted that the surface of the rotator is separately painted into a first color and a second color, a pigment is mixed with the material of the rotator, and the first surface and the second surface are formed by the color of the material itself. You may do so. The plurality of rotating bodies are rotatably stored in a sheet in a planar manner. Note that the first color and the second color may be a single color or a plurality of colors.

The applying means applies a first surface or a second surface of the sheet to a plurality of rotating bodies which are predetermined in the sheet and are arranged in an area where an image is formed, based on the image data. An electric or magnetic field for directing to the surface is selectively applied.

Here, when an electric field or a magnetic field is applied to the rotating body, the rotating body rotates in a direction corresponding to the direction of the electric field or the magnetic field. Therefore, based on the image data,
When an electric field or a magnetic field for directing the first surface or the second surface to the surface of the sheet is selectively applied, an image can be formed using a plurality of rotating bodies.

[0011] In the present invention, the applying means is arranged so that the first surface or the second surface of the rotating body disposed in the area is directed to the sheet surface. Immediately before applying the first electric field or magnetic field for directing the surface to the surface of the sheet, a second electric field or magnetic field having a polarity opposite to that of the first electric field or magnetic field is applied.

That is, the present inventors have obtained a number of experiments,
When an electric field or the like having the opposite polarity to that of the electric field or the like is applied just before applying an electric field or the like for causing the predetermined surface of the rotating body to face the sheet surface just before applying the electric field or the like to the predetermined surface of the rotating body, The inventors have found that the surface faces the sheet surface at a high speed and with high accuracy, and arrived at the present invention.

[0013] As described above, when the first surface or the second surface of the rotating body disposed in the area is directed to the sheet surface, the first surface or the second surface is set to the sheet surface. Immediately before applying the first electric field or magnetic field for directing, a second electric field or magnetic field having a polarity opposite to that of the first electric field or magnetic field is applied, so that a high-contrast image can be formed in a short time. .

Here, the application means includes a plurality of first electrodes arranged in a predetermined direction on the sheet surface side of a predetermined region where an image of the sheet is formed, and a predetermined electrode for forming an image of the sheet. A plurality of second electrodes disposed in a direction intersecting a predetermined direction on the back side of the sheet in a region provided, and the first surface of the rotating body disposed in the region facing the sheet surface. Immediately before applying a first voltage to the first electrode and the second electrode corresponding to the rotator to cause the first surface to face the surface of the sheet, the first electrode and the second electrode have a polarity opposite to that of the first voltage. And voltage applying means for applying the second voltage.

Note that a matrix structure is formed by the plurality of first electrodes and the plurality of second electrodes. Further, the first electrode may be an electrode plate whose longitudinal direction is a predetermined direction, or may be an electrode row in which a plurality of electrodes are arranged in a predetermined direction. The second electrode may be an electrode plate whose longitudinal direction intersects a predetermined direction, or may be an electrode row in which a plurality of electrodes are arranged in a direction intersecting the predetermined direction.

According to a second aspect of the present invention, an image forming apparatus includes a first surface of a first color and a second surface of a second color different from the first color.
A plurality of rotators having electric charges or magnetic charges having different sizes on the first surface and the second surface, and a sheet accommodating the plurality of rotators so as to be rotatable in a plane. When,
A plurality of rotating bodies that are predetermined in the sheet and are arranged in an area where an image is formed; and a first surface or a second surface facing the surface of the sheet based on data of the image. Application means for selectively applying an electric or magnetic field of
It has.

In the second aspect of the present invention, the plurality of rotators disposed in the region are divided into a plurality of rotator groups having different electric or magnetic fields for starting rotation, and belong to each rotator group. The rotating body is disposed over the area.

[0018] In this case, the application means includes a first unit for turning the first surface of the rotating body disposed in the region toward the sheet surface, and a first surface for turning the first surface toward the sheet surface. Immediately before applying the electric or magnetic field, a second electric or magnetic field having a polarity opposite to that of the first electric or magnetic field is applied, and the magnitude of the second electric or magnetic field and the magnitude of the second electric or magnetic field are determined based on the data. At least one of the time for applying the magnetic field may be controlled.

As described above, according to the present invention, the plurality of rotators are divided into a plurality of rotator groups having different electric or magnetic fields for starting rotation, and the rotators belonging to each rotator group are arranged over the region. doing. Further, a first surface or a second surface of the rotating body disposed in the region is directed to the sheet surface, and a first surface or the second surface of the rotating body is directed to the sheet surface. Immediately before applying the electric or magnetic field, a second electric or magnetic field having a polarity opposite to that of the first electric or magnetic field is applied.
At this time, at least one of the magnitude of the second electric field or magnetic field and the time for applying the second electric field or magnetic field is controlled based on the image data. Therefore, the rotator of the rotator group rotates according to at least one of the controlled magnitude of the second electric field or magnetic field and the time for applying the second electric field or magnetic field. Therefore, halftone display can be performed.

The application means may be configured such that, after an image is formed in the area, the magnitude of the second electric field or magnetic field and the time for applying the second electric field or magnetic field when another image is overwritten on the area. May be different from the value when the image is formed.

[0021]

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

First, an outline of the image forming apparatus according to the present embodiment will be described. FIGS. 1 to 3 show two-color rotating sphere particles having a black first surface and a white second surface, wherein the first surface and the second surface have different surface charges in an electric field. The basic operation in the case of using is shown.

FIG. 1A is a top view of a scanning electrode.
FIG. 1B is a cross-sectional view in which the scanning electrodes are arranged on the left side, and is a diagram illustrating a state where the two-color rotating spherical particles in the selected state are rotated from white to black by 180 °. FIG. 2 is a diagram showing the shape of a voltage pulse applied to a scanning electrode and the shape of a voltage pulse applied to a data electrode in a selected pixel in the above operation state. FIG. 3 is a diagram showing a state when the image is rotated 180 ° from black to white under the same observation conditions.

As shown in FIG. 1, a colorless and transparent elastomer 2 rotatably holds two-color rotating spherical particles 1 in a cavity 3. The cavity 3 is filled with a liquid formed for the two-color rotating spherical particles 1 to move freely. These are arranged between the upper scanning electrodes 4 and 4N and the lower data electrodes 5 and 5N to form a simple matrix configuration.

The scanning electrodes 4 in this simple matrix configuration
Will be described with reference to the shaded portion 6 which is a selected pixel. The two-color rotating spherical particles 1 are operated by an electric field generated between the upper scanning electrode 4 and the lower data electrode 5. The electric field required for rotating the two-color rotating sphere particles 1 is generated between the voltage pulse 7 applied to the scanning electrode 4 and the data voltage 8 applied to the lower data electrode 5. When the threshold voltage in the rotation operation of the color rotating sphere particles is exceeded, rotation starts.

In the present embodiment, a two-color rotating pulse is applied by applying a voltage pulse 9 of the opposite polarity corresponding to the threshold characteristic of each two-color rotating spherical particle immediately before applying the voltage pulse 7 of the scanning electrode. 18 spherical particles 1
It is designed to rotate by 0 °. In this way, by applying the voltage pulse 9 of the opposite polarity suitable for the rotating operation of each two-color rotating sphere particle, the two-color rotating sphere particle 1 is quickly rotated by 180 ° to a state shown by reference numeral 1N, When this movement is observed from the upper scanning electrode side, the white color is well inverted from white.

The timing of the voltage pulse applied to the lower data electrode and the voltage pulse applied to the upper scan electrode at this time will be described with reference to a second example. The pulse 10 applied to the lower data electrode in the selected pixel in the shaded area 6
Is a Low output during a period 11 in which a reverse polarity voltage pulse is applied to the scan electrode, and a Hi output only during a period 12 in which a drive voltage pulse is applied to the scan electrode. Thus, the effect of the reverse polarity application pulse is made effective by setting the period of the pulse applied to the lower data electrode to only the drive voltage pulse application period. With the above pulse application,
By sequentially applying this scanning voltage pulse to all the upper scanning electrodes, a good image can be obtained in a short time. Then, as shown in the figure, the rotated two-color rotating spherical particles contact the inner wall of the cavity to maintain the state, and thus the written image has a memory property to retain the current position. Become.

FIG. 3 illustrates a voltage pulse applied to the upper scanning electrode when the two-color rotating spherical particles are rotated by 180 ° from black to white, contrary to FIG. In the hatched portion 13 in FIG.
When observed from the side, a black surface (first surface) is visible. In this state, the application of the voltage pulse 16 causes the two-color rotating spherical particles 14 to be inverted. Here, as in FIG. 1, the opposite polarity voltage pulse 17 suitable for the rotating operation of each two-color rotating spherical particle. Is applied immediately before the voltage pulse 16 to rotate more favorably, and the state shown by reference numeral 14N is obtained.
At this time, the voltage pulse applied to the lower data electrode in the selected pixel in the hatched portion 13 is the output Lo which is opposite to that in FIG.
w.

The difference between FIG. 1 and FIG. 3 lies in the polarity of the voltage pulse applied to the scanning electrode. That is, it is necessary to change the polarity of the voltage pulse applied to the scanning electrode depending on whether the initial state of the two-color rotating sphere particles is white or black as viewed from the scanning electrode. Further, since the drawn image has a memory property, in order to rotate from the white surface (the second surface) to the black surface or from the black surface to the white surface, a voltage equal to or higher than the rotation operation start voltage is applied in each state. There is a need to. Further, since the threshold characteristics of the two-color rotating sphere particles in the rotating operation vary depending on the diameter and the charge control material included in the material, it is necessary to set the reverse polarity applied pulse voltage value corresponding to the rotation in order to rotate 180 °. There is.

The details will be described below. The image forming apparatus according to the present embodiment has 64 simple matrix electrodes.
It has an image forming area of 0 × 480 dots (not limited to this number of dots).

As shown in FIG. 4, the surface of the image forming apparatus is divided into two colors, white and black, and has a diameter of about 1 mm.
A plurality of two-color rotating sphere particles 28 of 00 μm, a coloring sheet 27 for accommodating the plurality of two-color rotating sphere particles 28 so as to be rotatable in a plane, and a surface of the coloring sheet 27 so as to cover the coloring sheet 27; A transparent Row glass substrate 20 in which 480 ITO electrodes each having a rectangular shape arranged in a direction perpendicular to a predetermined direction (horizontal direction of the paper) at a pitch of 0.4 mm and having a predetermined length in a longitudinal direction are arranged; A transparent column in which 640 rectangular ITO electrodes arranged in a predetermined direction at a pitch of 0.4 mm in each direction and having a longitudinal direction perpendicular to the predetermined direction are arranged on the back side of the coloring sheet 27 so as to cover the A glass substrate 24.

The image forming apparatus has 480 Rows.
Upper scanning voltage output circuit board (hereinafter referred to as Row drive circuit) 18 including drive IC group 19, Row drive IC group 1
9 and a Row flexible substrate 21 for connecting 480 ITO electrodes on the Row glass substrate 18. Note that, specifically, from the Row drive IC group 19 of the Row drive circuit 18, 480 output lines are connected to each ITO electrode on the Row glass substrate 20 via the Row flexible substrate 19. The row drive circuit 18 and the ITO electrode on the row glass substrate 20 are connected to R
The ow flexible substrate 21 is connected by an anisotropic conductive sheet.

Further, the image forming apparatus has a lower data voltage output circuit (hereinafter referred to as Co) having a Column drive IC group 23.
lum driving circuit) 22 and Column driving IC group 2
3 and 640 ITO on Column glass substrate 24
Column flexible substrate 25 for connecting electrodes
And Specifically, from the column drive IC group 23 of the column drive circuit 22, 64
Zero output lines are connected to each of the ITO electrodes on the column glass substrate 24 via the column flexible substrate 25. Column drive circuit 22 and ITO electrode on Column glass substrate 24 and Column
The mn flexible substrate 25 is connected by an anisotropic conductive sheet.

The row glass substrate 20 and the column glass substrate 24 are adhered to each other with a coloring sheet 27 interposed therebetween via a sealing material 26.

A cavity 29 having a slightly larger diameter than the two-color rotating spherical particles 28 is formed in the coloring sheet 27, and the cavity 30 is filled with a liquid 30, for example, Isopar L from Exxon. The two-color rotating spherical particles 28 are arranged in the liquid, and the two-color rotating spherical particles 28 can move freely.
The two-color rotating sphere particles 31 with the cavity 29 are
It is densely arranged in a silicone rubber 31 having a thickness of about 250 μm.

Next, the operation of the present embodiment will be described. With reference to FIG. 5, a method of displaying a binary image will be described using a 5 × 5 dot matrix 32 as a part of the device display unit.

In the present image forming apparatus, a write voltage 33 is sequentially applied to the Row ITO electrode, and the
An image is formed by line-sequential scanning in which a data voltage 34 is applied to the electrodes. In FIG. 5, the staggered image is formed by forming the selected black portion, for example, 35, after whitening the entire screen once. This state will be described in more detail with reference to FIG. In the present image display device, the entire surface of the coloring sheet is temporarily turned white as indicated by reference numeral 36 by applying a scanning voltage to the Row electrode. Looking at a microscopic view 38 of a part of this coloring sheet, all the two-color rotating sphere particles have the white side facing the surface side of the coloring sheet. In this state, the reverse polarity applied pulse voltage is set so that the two-color rotating spherical particles are sufficiently rotated, and the voltage is sequentially applied to the Row electrode and the Column electrode as shown in FIG. indicate. Observing the microscopic view 41 of a part 40 of the color forming sheet on which the staggered image is formed,
As shown by reference numeral 42, the two-color rotating sphere particles of the selected pixel are rotated by 180 ° and turned black.
As indicated by reference numeral 43, the two-color rotating spherical particles of the non-selected pixels remain white. At this time, as indicated by reference numeral 41, the two-color rotating sphere particles located between the selected pixel and the non-selected pixel are rotated only by 90 °, and contribute to good pixel separation between white and black.

FIG. 7 shows the effect of the reverse polarity voltage pulse applied immediately before the application of the driving voltage pulse in the driving method according to the present embodiment. In this experiment, as in the above-described image forming method, the entire surface was white and then only the selected pixels were black. As shown in FIG. 8, the two-color rotating spherical particles in the coloring sheet in FIG. 7 include a plurality of particles having different diameters in order to change the threshold characteristics in each rotating operation. On the horizontal axis of FIG. 7, when only the operating voltage pulse of the two-color rotating spherical particles is applied,
When a reverse polarity voltage pulse of half the operating voltage is applied immediately before, when the reverse polarity voltage is equal to the operating voltage, when the reverse polarity voltage is 1.5 times the operating voltage,
Shows the reflectance of both the unselected pixel (white state) and the selected pixel (black state) when the reverse polarity voltage is twice the operating voltage and each waveform pulse is applied once on the vertical axis. doing. Code 45N, 46N, 47N, 48N, 4
As shown in FIG. 9N, the amount of change from white to black varies depending on the magnitude of the reverse polarity voltage pulse. Further, as shown by reference numerals 45 to 49, even if a pulse voltage necessary for rotating the two-color rotating spherical particles is applied,
The reflectance of the non-selection part (white part) does not change.

Further, the state of these state changes will be described with reference to a microscope diagram shown in FIG. FIG. 8 illustrates only the state of FIG. 7. The coloring sheets used in this experiment were 50, 5 in descending order of diameter.
Two-color rotating spherical particles of sizes 1, 52 and 53 are arranged. When the pulse voltage shown in FIG. 7 is applied to the coloring sheet, the rotating sphere particles having the respective particle diameters become 50 particles.
N, 51N, 52N, and 53N. That is, only the rotating sphere particles 53 having a small particle diameter are inverted to black, and are in a state of 53N. Next, in the rotating spherical particle 52 having the smaller particle size,
Since the rotation operation voltage is different due to a slight variation in manufacturing, 52N that does not rotate and 54 that slightly rotates are recognized.

When the pulse voltage shown in FIG. 7 is applied,
The rotating sphere particles of each particle size are 50NN, 51NN,
52NN, 53NN, 180 ° regardless of particle size
It rotates and turns the black surface. So, for example,
When the staggered image shown in FIG. 5 is displayed by the scanning voltage pulse of FIG. 7, the staggered image is not a white / black staggered image as shown in FIG.

FIG. 10 shows the result of a conventional experiment, that is, a similar experiment when no reverse polarity pulse is applied.
Shown in In this experiment, in order to change the density of the selected pixel, the value of the applied pulse voltage is changed so as to increase in the order of. These voltages are
Are similar to those in FIG. 7, and are prepared so that the selected pixels (black portions) show the same values as in FIG. Also, as in the experiment of FIG. 7, the entire surface of the coloring sheet was first set to white, and only selected pixels were changed to black. When the reflectance of the non-selected pixel (white portion) at each applied pulse voltage is determined, the reflectance of the non-selected pixel (white portion) becomes 55, 56, 57, 58, and 59. As shown,
The reflectivity decreases. This is because the threshold characteristics in the rotating operation of the two-color rotating sphere particles having the respective particle diameters arranged in the coloring sheet vary. That is, the pulse voltage applied to the selected pixel affects the non-selected pixel, and the black surface of the non-selected pixel faces the surface of the coloring sheet according to the magnitude of the pulse voltage. As described above, even if the threshold characteristic in the rotation operation of each of the two-color rotating spherical particles is changed in order to obtain a halftone density, the reflectance of the white part is not used when the applied voltage pulse of the present embodiment is not used. When the Kuril image shown in FIG. 5 is displayed, only an image having low contrast and low image crystal quality is obtained as shown in FIG.

FIG. 12 shows an image forming apparatus which performs halftone display according to a modification of the image forming apparatus as described above.
The present image display device has a 6
An image display unit 60 of 40 × 480 dots, a control unit 61 and a signal input unit 62 are provided. Image display section 6
Character images such as alphabet characters 63 and katakana characters 64 are displayed on 0 according to a signal input from the signal input unit 62. As the halftone display, by changing the value of the reverse polarity pulse voltage and repeating the screen sequential scanning, the darkest black 65 to the lightest blacks 66, 67, 68 can be displayed. This state will be described sequentially with reference to FIG. FIG. 13 shows a state in which the character image 63 having the same density and the darkest black portion 65 are drawn.
13 (B), an image 64 is drawn with a character having the same density as the character image 63 in FIG. 13 (B). Further, FIG.
The image shown in FIG. 12 is formed by drawing the character image 63 drawn earlier and the image 67 different in density from the darkest black 65 and continuing these operations. At this time, since the present image display device has a memory property, even if, for example, the lightest black color 68 is drawn after the darkest black color 65 is drawn, the darkest black image 65 drawn first disappears. Is kept without. That is, according to the image output apparatus, it is possible to draw another image later with the same density or a different density with respect to the initially drawn image. Also, since the previously drawn image is retained unless erased by white drawing, it can be drawn only with the signal of the image to be additionally drawn, thus reducing the drawing power. Can also. Furthermore, these drawn images can be partially erased and rewritten by the white drawing method shown in FIG.

As described above, in an image display device in which a color forming layer in which two-color rotating spherical particles are arranged in a sheet shape is driven by a simple matrix electrode, the two-color rotating spherical particles can be favorably rotated. By controlling the value of the reverse polarity voltage pulse, it is also possible to display the intermediate density, and by applying this pulse voltage, the rotation of the two-color rotating sphere particles is accelerated, so that the image display time can be reduced. Become.

Conventionally, in order to obtain an image having a good contrast, two-color rotating spherical particles of the same size are selected so that the threshold characteristics during the rotating operation become uniform, thereby forming a color sheet. However, by using the image forming method of the present invention, it is not necessary to sort out the two-color rotating spherical particles, so that the manufacturing cost can be reduced.

In the example described above, an electric field or ion particles are used to charge the surface of the two-color rotating spherical particles and rotate the two-color rotating spherical particles, but the present invention is not limited to this. Instead, at least the surface of the two-color rotating sphere particles is made of a magnetic material, and a coil is arranged on the back surface of the coloring sheet corresponding to each pixel of the image forming area, and the direction of the current flowing through the coil is changed. The two-color rotating spherical particles may be rotated by using a magnetic force.

In the above-described two-color rotating sphere particles, the surfaces of the two-color rotating sphere particles are separately painted black and white, but the present invention is not limited to this. The first surface and the second surface may be formed by mixing a pigment with the material or by the color of the material itself. The two-color rotating spherical particles are not limited to black and white rotating spherical particles, and rotating spherical particles of other colors may be employed. The first color on the first surface and the second color on the second surface may be a single color or a plurality of colors.

In the above-described example, an example using a two-color rotating sphere has been described. However, the present invention is not limited to this, and a cylindrical rotating body may be used.

Further, in the above-described example, a plurality of two-color rotating spheres having different sizes are used for halftone display. However, the present invention is not limited to this, and a plurality of two-color rotating spheres having different masses are used. A spherical body may be used, and the arrangement interval of the ITO electrodes is gradually increased for each predetermined section on the front surface side of the coloring sheet, and the number of ITO electrodes to which a voltage is applied is controlled for each predetermined section. Is also good.

In the above-described example, the magnitude (amplitude) of the voltage pulse of the opposite polarity is controlled for halftone display. However, the present invention is not limited to this. The application time may be controlled.

[0050]

As described above, according to the present invention, the first surface or the second surface of the rotator disposed in the area where an image is formed is directed toward the sheet surface by using the first surface. Or the second
Immediately before applying the first electric field or magnetic field for directing the surface of the sheet to the surface of the sheet, the second voltage or magnetic field having the opposite polarity to the first voltage or magnetic field is applied, so that an image with good contrast can be shortened. This has the effect that it can be formed in time.

According to the present invention, by controlling at least one of the magnitude of the second electric or magnetic field and the time for applying the second electric or magnetic field, the magnitude of the second electric or magnetic field can be controlled. Since the rotator of the rotator group is rotated according to at least one of the application time of the electric field or the magnetic field, halftone display can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a shape of a voltage application pulse to a scanning electrode when rotating two-color rotating spherical particles from a white surface to a black surface by the image forming apparatus according to the present embodiment.

FIG. 2 is a diagram illustrating timings of a pulse voltage applied to an upper scanning electrode and a pulse voltage applied to a lower data electrode in a hatched portion in the image of FIG. 1;

FIG. 3 is a diagram showing a shape of a voltage application pulse to a scanning electrode when rotating two-color rotating spherical particles from a black surface to a white surface.

FIG. 4 is a schematic diagram of an image display device.

FIG. 5 is a diagram showing a staggered display image when a voltage pulse according to the present embodiment is applied.

FIG. 6 is an enlarged view of a part of a display image when a voltage pulse according to the present embodiment is applied, and a diagram showing an operation of the two-color rotating sphere particles before and after the application of the voltage pulse.

FIG. 7 is a diagram illustrating voltage pulse application according to the present embodiment;
FIG. 7 is a diagram illustrating a change in density according to a value of a reverse polarity pulse voltage.

FIG. 8 is a diagram showing an operation state of two-color rotating spherical particles when different densities are drawn.

FIG. 9 is a diagram showing a staggered display image when a reverse polarity pulse voltage is applied so as to develop an intermediate density.

FIG. 10 is a diagram illustrating reflectance in a white portion and a black portion when a staggered image is displayed according to the related art.

FIG. 11 shows a staggered image displayed by the conventional technique.
It is a figure showing the image.

FIG. 12 is a schematic diagram of an image forming apparatus according to a modification.

FIG. 13 is a diagram illustrating a state in which an additional image is drawn.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotating spherical particle 2 Elastomer 3 Cavity 4 Upper scanning electrode 5 Lower data electrode 7 Pulse voltage. 8 Data voltage. 9 Reverse polarity voltage pulse

Claims (4)

[Claims] A first surface having a first color and a second surface having a second color different from the first color, and having a first surface and a second surface each having a size different from the first color; A plurality of rotating bodies having different electric charges or magnetic charges; a sheet accommodating the plurality of rotating bodies so as to be rotatable in a plane; and a sheet arranged in an area which is predetermined in the sheet and forms an image. Applying means for selectively applying, to the plurality of rotating bodies, an electric field or a magnetic field for directing the first surface or the second surface to the surface of the sheet based on the data of the image; In the forming apparatus, the application unit may be configured to set the first surface or the second surface of the rotator disposed in the area to face the sheet surface. Immediately before applying the first electric or magnetic field for directing to the surface of the sheet, a first electric or magnetic field having a polarity opposite to that of the first electric or magnetic field is applied. Image forming apparatus for applying the electric or magnetic field. 2. A method according to claim 1, further comprising a first surface of a first color, a second surface of a second color different from the first color, and a size of the first surface and the second surface. A plurality of rotating bodies having different electric charges or magnetic charges; a sheet accommodating the plurality of rotating bodies so as to be rotatable in a plane; and a sheet arranged in an area which is predetermined in the sheet and forms an image. Applying means for selectively applying, to the plurality of rotating bodies, an electric field or a magnetic field for directing the first surface or the second surface to the surface of the sheet based on the data of the image; In the forming apparatus, the plurality of rotating bodies disposed in the region are divided into a plurality of rotating body groups having different electric or magnetic fields for starting rotation, and the rotating bodies belonging to each rotating body group are located in the region. Image forming apparatus arranged over the 3. The application unit includes: a first surface or a second surface of a rotating body disposed in the area, the first surface or the second surface of the rotating body facing the sheet surface. Immediately before applying the first electric field or magnetic field for directing the first electric field or the magnetic field to the surface of the second electric field or the second electric field or the magnetic field having the opposite polarity to the first electric field or the magnetic field, 3. The image forming apparatus according to claim 2, wherein at least one of a magnitude of the magnetic field and a time for applying the second electric field or the magnetic field is controlled. 4. The method according to claim 1, wherein the applying unit is configured to form an image on the area, and to apply a second electric field or magnetic field and a magnitude of a second electric field or magnetic field when another image is overwritten on the area. 4. The image forming apparatus according to claim 3, wherein at least one of the values is different from a value when the image is formed.