JP2735719B2 - Image display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display apparatus for forming an image by ejecting toner onto a display medium.

[0002]

2. Description of the Related Art Conventionally, as this type of image display device,
For example, there was one shown in FIG. In the figure, 1 is a photosensitive member, 2 is a display medium, 3 is a driving roller, 4 is a freely rotatable pulling roller, 5 is a charging device having a corona wire stretched perpendicular to the longitudinal direction of the photosensitive member 1, 6 In the figure, light-emitting diodes (hereinafter simply abbreviated as LEDs), which are not shown, are arranged in a substantially straight line toward the surface of the photoreceptor 1 in a direction perpendicular to the longitudinal direction of the photoreceptor 1, that is, in the figure, perpendicular to the paper surface. Exposure device, 7 is a developing device, 8 is a toner carrier having a built-in permanent magnet, 9 is toner, 10 is a bias power supply, 11 is glass, 12 is a neutralization lamp, 13 is a cleaning blade, and 14 is a display unit. The toner carrier 8 is pressed against the photoconductor 1 with the display medium 2 interposed therebetween.

The photoconductor 1 is a cylindrical component having a photoconductor on the surface. The photoconductor on the surface of the photoconductor 1 is charged to a positive polarity by a charging device 5 at a potential of about several thousand volts, and at the same time, the drive roller 3 rotates clockwise at a predetermined speed in the drawing. For this reason, the photoconductor 1 is rotated via the display medium 2, and the entire surface is uniformly charged to a predetermined polarity. At this time, the display medium 2 is always given a predetermined tension by the pulling roller 4 so as not to bend.

Along with this, the exposure device 6 receives a drive signal corresponding to an image to be displayed from a drive circuit (not shown), and a part of the LEDs arranged substantially linearly in a direction perpendicular to the rotation direction of the photoconductor 1. Alternatively, all of them are selectively made to emit light. By this light emission, a predetermined portion of the surface of the photoconductor 1
Upon selective exposure, the surface photoconductor is neutralized. In this way, an unillustrated electrostatic latent image is formed on the surface of the photoconductor 1 by the charge distribution.

After the electrostatic latent image is formed on the surface of the photosensitive member 1 in this manner, the developing device 7 causes the toner 9 to adhere to the surface of the display medium 2. Specifically, for example, the toner 9 is positively charged to about several tens of volts, and is then attached to the surface of the toner carrier 8 having a built-in permanent magnet. after that,
The toner 9 is pressed against the photoconductor 1 by the toner carrier 8.

At this time, the toner 9 does not adhere to the charged portion of the display medium 2, that is, the portion overlapping the portion of the photosensitive member 1 where the charge has not been removed, and is immediately peeled off. This is because the potential of the toner 9 and the potential of the display medium 2 have the same polarity. On the other hand, the toner 9 remains attached to the uncharged portion of the display medium 2. Thus, a toner image is formed on the surface of the display medium 2.

Thereafter, when the display medium 2 is further moved, the toner image moves to the vicinity of the display window 14. Thus, the toner image can be viewed from the outside through the display window 14. As the display medium 2 moves, the photoconductor 1 further rotates. Since the electrostatic latent image on the photoconductor 1 is no longer needed after the electrostatic latent image is formed on the display medium 2,
The image is erased by a static elimination lamp 12 provided near the photoconductor 1. Specifically, the photosensitive member 1 is exposed to light over the entire region in the longitudinal direction by the charge removing lamp 12, and the charge is removed from the photosensitive member 1.

When the display of the toner image on the display medium 2 becomes unnecessary, the toner image is sent to the cleaning blade 13 by the movement of the display medium 2. The tip of the cleaning blade 13 is in contact with the display medium 2 and forcibly peels off the toner 9 having formed the toner image from the surface of the display medium 2. The toner 9 thus peeled is collected by the developing device 7 and reused.

[0009]

However, the above-described display device has the following problems. First, it takes time to form an image. The above-described toner image forming process is obtained by omitting the heat fixing process from the generally known electrophotographic printing process. Therefore, continuous charging by the charging device 5 and pressure bonding of the toner by the toner carrier 8 necessarily require some time.

Second, the toner itself is unstable. In the above-described display device, variations in the charge capacity of the toner, aging, and the like affect the finish of the toner image, particularly, the contrast and the like. The display medium itself has the same problem.

Third, the cost is high. For example, the photoreceptor 1, which greatly affects the finish of the toner image, has a high component cost, and if the surface is scratched, the electrostatic latent image has a great adverse effect. Furthermore, periodic parts replacement was required due to surface wear and the like. Also, the exposure apparatus 6 itself has been a factor that increases the cost of the entire apparatus.

[0012]

In order to solve the above problems, the present invention adopts the following configuration. That is, in the image forming unit inside the display device, the number of nozzles corresponding to the resolution required for the toner image is provided on the toner image forming surface side of the display medium. A chargeable toner is supplied to the nozzle. In addition, an independent electrode corresponding to each nozzle is provided near the nozzle, and a flat electrode is provided on the opposite side of the nozzle with respect to the display medium.

An electric field is generated by applying potentials of opposite polarities to the nozzle side electrode and the plane electrode. Fine irregularities are provided on the surface of the display medium, and the toner enters between the irregularities so that a stable image is maintained without depending on static electricity.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic explanatory view showing the configuration of one embodiment of the present invention. In the figure, reference numeral 15 denotes a display medium, which is made of a flat white plastic plate. 1
6 is a foil-shaped aluminum flat electrode, 17 is a protection resistor, 18 is a high-voltage power supply for generating a DC high voltage, 19 is a toner print head which is a characteristic part of the present invention, and 20 is a display surface 15a of the display medium 15 A cleaner 21 for collecting the toner 9 is a pipe for sending the toner 9 collected by the cleaner 20 to the toner print head 19.

In this embodiment, the display medium 15 is
It is a white plastic plate having a thickness of about 10 μm, and its surface constitutes a display surface 15a. This display surface 15a
Are formed with fine irregularities by embossing. A flat electrode 16 is provided on the back side of the display medium 15.
Is affixed. The flat electrode 16 is made of a conductor such as aluminum, and is entirely provided with a high-voltage power supply 18.
, A DC voltage of about 1900 to 3000 V (volt) is applied through a protection resistor 17.

The toner print head 19 can freely move on the display surface 15a integrally with the cleaner 20 by a head drive mechanism (not shown). This drive mechanism may be of a type used for a normal serial printer.

FIG. 2 is a sectional view showing the outline of the configuration of the toner print head 19 and the cleaner 20. In the figure, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted. Hereinafter, the same applies to each drawing.

In the figure, 22 is a charging roller, 23 is a feeding roller, 24 is a pressure roller, and 25 is a nozzle. The feed roller 23 and the pressure roller 24 are rotated in directions indicated by arrows A and B, respectively, by driving means (not shown). Further, the nozzles 25 are arranged at a predetermined interval from each other and are arranged in a row or in a staggered manner as shown in FIG. When the nozzles 25 are arranged in a line, it is desirable that eight nozzles 25 be arranged within one millimeter from the viewpoint of required resolution. 26 is an electrode. The electrode 26 has a cylindrical shape and is provided so as to surround the nozzle 25. The hollow portion of the core of the electrode 26 is for the passage of the toner 9. The toner 9 is a black spherical insulating toner, and may be the same as that used in a normal electrophotographic process. Feeding roller 23 and pressure roller 24
Is made of an insulator, while the inside is formed by a conductor, and the potential is always set to 0 by a grounding means (not shown).
It is kept at V.

The toner 9 deposited inside the toner print head 5 is appropriately stirred by a charging roller 22 provided at the bottom of the toner print head 19, and charged at the same time. Through the nozzle 25. Nozzle 25 has toner 9
A cylindrical electrode 26 is provided around the holes arranged in a predetermined shape so as to let the air pass therethrough. The electrode 26 is applied with a potential having the same polarity as that of the toner 9. The electrode 26 and the toner 9 generate an electric repulsive force, thereby preventing the toner 9 from jumping out of the nozzle 25. In this case, the potential of the electrode 25 is suitably, for example, about −10 V.

On the other hand, when the toner 9 is ejected from the nozzle 25, the polarity of the electrode 26 is reversed, that is, plus three.
A potential of about 0 V is applied. Then, an electric field is generated between the electrode 26 and the plane electrode 16 in the direction from the electrode 25 to the plane electrode 16, and the positively charged toner 9 in the electric field
5 jumps out toward the display medium 15.

The display surface 15a of the display medium 15 is embossed as described above, and fine irregularities are uniformly distributed. The toner 9 enters this portion and is fixed. By utilizing this, while appropriately controlling the potential of the electrode 25, the toner print head 19 is moved relative to the display surface 15a in synchronization with this control, whereby the display surface 15
A visible toner image (not shown) is formed on a.

When it is necessary to erase or rewrite the toner image on the display surface 15a, the cleaner 20 moves together with the toner print head 19 inside the cleaner 20.
A negative pressure is generated by intake means (not shown), and the display surface 1
By sucking the toner 9 on 5a into the cleaner 20, the toner image can be erased. At this time, as in the case of forming the toner image, if the cleaner 9 is moved by the above-described driving means with respect to the display surface 15a and the toner 9 is sucked, the toner image can be erased over the entire display surface 15a. Will be possible. Further, since the cleaner 20 moves together with the toner print head 19, it is possible to form a new toner image at the same time that the toner image is erased by the cleaner 20.

The toner 9 thus sucked into the cleaner 20 is sent again to the toner print head 19 through the pipe 21 and reused. In order to reuse the toner 9 in this way, the durability of the toner 9 itself is required. However, at present, the toner removed from the photosensitive drum at the time of development is collected and reused in an electrophotographic printer. Since the so-called toner recycling technology has been put to practical use, the use of this technology does not cause any trouble in the present invention.

When a toner image is erased by sucking the toner 9 into the cleaner 20, a high voltage having the same polarity as the toner 9 is applied to the flat electrode 15, not only depending on the negative pressure of the cleaner 20. Alternatively, the toner 9 may be easily separated from the display surface 2a by utilizing the electric repulsion generated between the flat electrode 15 and the toner 9.

Further, the color of the display medium 15 is not necessarily limited to white depending on the use. For example, the display surface 15a is divided into a large number of fine block-shaped portions in advance, each of which is appropriately colored red, blue, green, or the like. By doing so, color display can be performed. This method is intended to obtain the same effect as that of a color television using the toner print head 19, and as long as a resolution of about 8 nozzles per millimeter can be realized as described above, it is sufficient for practical use. It is expected that color display will be possible. In this case, it is desirable that a concave portion (hereinafter, simply referred to as a concave portion) of the unevenness provided on the display surface 15a be a square, a circle, or the like having the same size.

Further, since it is necessary to surely mask the concave portions one by one, the toner print head 19 and the display medium 15
It is necessary to provide a means that can adjust the relative position between them with an accuracy corresponding to at least the size of one recess.
For this purpose, for example, a pinhole is provided on the display medium 15 side, and a light source is provided on the flat electrode 16 side of the pinhole.
A method of detecting the light emitted from the light source and passing through the pinhole by a light receiving element provided on the toner print head 19 side is conceivable. Also, depending on the driving mechanism of the toner print head 19, the accumulated error of the position detection of the toner print head 19 may affect the color reproducibility. Therefore, measures such as providing a plurality of pinholes and light sources are necessary. It is also conceivable.

[0027]

As described above, according to the present invention, there is an effect that a toner image can be formed on a display medium at high speed and erasable without using an electrophotographic process. . Further, in the configuration of the present invention, the structure of the display medium is simple, and the display medium does not have a mechanically movable part, so that there is little trouble and large-screen display can be performed at an overwhelmingly low cost. It has the effect of becoming.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a configuration of an embodiment of the present invention.

FIG. 2 is a sectional view showing a configuration of a toner print head and a cleaner.

FIG. 3 is an explanatory view showing an example of an arrangement of nozzles.

FIG. 4 is an explanatory view showing an example of a conventional apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photoconductor 2 display medium 5 charging device 6 exposure device 7 developing device 8 toner carrier 9 toner 10 bias power supply 11 glass 12 static elimination lamp 13 cleaning blade 14 display unit 15 display medium 16 flat electrode 19 toner print head 25 nozzle 26 electrode

Claims (1)

(57) [Claims] 1. A toner print head having a portion for storing toner, a nozzle provided in a part of a print head, and a first electrode provided around the nozzle, facing the toner print head. A display medium having fine irregularities on the surface on the side facing the toner print head,
The display medium includes a flat electrode provided on a surface opposite to the surface having the fine irregularities, at least at a position facing the print head, and ejects the toner onto the surface of the display medium from the nozzle. Forming an image with the toner.