JPS62127853A - Image forming method - Google Patents

Abstract

PURPOSE:To form easily a digital image by forming a toner as a thin layer on a picture element electrode, and flying it at every picture element in accordance with image information. CONSTITUTION:When a developer 12 is held on the surface of a sleeve 11, and moved successively onto a picture element electrode plate 1 by a rotation of the sleeve 11, and also the picture element electrode plate 1 and the sleeve 11 are moved relatively, a uniform toner thin layer 13 can be formed. To a gate electrode of a field effect transistor 4, a picture element signal corresponding to image information is inputted, and in a position where a cylindrical electrode 18 and the picture element electrode plate 1 go to the most adjacent to each other, the cylindrical electrode 18 rotates so as to maintain a confronted position, and also it is provided so as to move horizontally and relatively against the picture element electrode plate 1. By moving said electrode so that a relative speed is not generated between both of them, an electric field can be scanned to the whole surface of the picture element electrode plate 1, and from a toner thin layer on the picture element electrode plate, a toner can be flown in accordance with image information.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a new image forming method using a powder developer (toner), and more specifically to a method for forming a digital image by using pixel electrodes. Regarding how it can be done.

(Prior Art) As methods for recording images using toner, electrophotographic methods such as Carlson process and NP process, and electrostatic recording methods using multi-stylus electrodes are known.

In the former method, an electrostatic charge is uniformly applied to the surface of the photoreceptor, and then image exposure is performed to eliminate charges in bright areas, thereby forming an electrostatic latent image corresponding to the original image. Then, this latent image is developed with toner to make it visible.

In addition, the latter uses multi-stylus electrodes on the dielectric surface and applies voltage to a specific stylus according to an image signal to form an electrostatic latent image.

This latent image is visualized by developing it with toner.

(Objective) The object of the present invention is to form a toner image by a method completely different from these known image forming methods.

In other words, a thin toner layer formed on a pixel electrode is transferred (flighted) onto a recording medium for each pixel electrode in response to an image signal.
The purpose of this invention is to provide a method for forming digital images based on a completely new idea of creating digital images.

(Structure) According to the present invention, a thin toner layer is formed on the pixel electrode plate,
A counter electrode is placed opposite to the toner thin layer via an insulating layer, and an electric field is applied between the pixel electrode plate and the counter electrode according to image information to inject charges into the toner particles. A method can be provided that achieves the above object by selectively flying toner to form a toner image on an insulator.

(Example) The image forming method of the present invention will be explained below based on the drawings.

The image forming method of the present invention is characterized in that a toner image is formed by causing toner particles to fly according to image information.

For this reason, when forming a toner image, a method is used in which a thin toner layer is once formed on the pixel electrode using a pixel electrode, and a voltage is applied to a specific pixel electrode to selectively fly the toner from this thin toner layer. is adopted.

FIG. 1 shows an example of a pixel electrode used in the image forming method of the present invention, which is in the form of an electrode plate. In the pixel electrode plate 1, a pixel electrode 3 arranged in a matrix and a field effect transistor (FET) generally indicated by 4 are provided on the surface of the base 2. This field effect transistor 4 includes, for example, a gate electrode 5 provided on a substrate 2, a gate insulating film 6, such as aSi3Na:H, covering the substrate 2 and the gate electrode 5 thereon, and It consists of a semiconductor 7, for example a-3i:H, provided on a gate insulating film, a source electrode 8 connected to one end of this semiconductor 7, and a drain electrode 9 connected to the other end of the semiconductor 7. . A pixel electrode 3 is provided on the insulating film 6 so as to be connected to the drain electrode 9. The source electrode 8 is grounded, and the field effect transistor 4 is interposed between the pixel electrode 3 and the ground. It is connected to a circuit (driver circuit).Furthermore, it is preferable that an insulating material is filled over the field effect transistors 4 between the pixel electrodes 3 so that the surface of the pixel electrode plate 1 is flat.

Image formation begins with uniformly forming a thin toner layer on this pixel electrode plate 1. As the toner forming means, a method as shown in FIG. 2 is suitably employed. That is, this method uses a magnetic brush. According to this method, sleeve 1
A uniform toner thin layer 13 is formed by holding the developer 12 on the surface of the sleeve 1 and moving it sequentially onto the pixel electrode plate l by rotating the sleeve 11, and by moving the pixel electrode plate l and the sleeve 11 relatively. can be formed. The sleeve 11 is a non-magnetic cylinder and constitutes the magnetic sleeve 10 by enclosing the magnet roll 14 therein.

The toner particles are retained on the magnetic sleeve 10 using a two-component developer in which toner particles are mixed with magnetic particles such as ferrite particles or iron powder, or a one-component developer in which a magnetic material is contained in the toner. This can be done by magnetically attracting it as a developer.

In FIG. 2, the field effect transistor 4 is represented as a switching element. The formation of a uniform toner thin layer 12 on the pixel electrode plate 1 is carried out after the signal input from the driver circuit so that all the pixel electrodes 3 are grounded.

In forming the toner thin layer 13 using the magnetic sleeve IO, in addition to the method of rotating the sleeve as described above, it is also possible to rotate only the magnet or to rotate both. Further, it is desirable to form a thin toner layer on the pixel electrode plate 1 by applying a bias voltage between the sleeve 11 and the pixel electrode plate l. In this case, an applied voltage of about 500 V can form a thin layer of several layers of toner particles.

Next, a flying method for forming a toner image from a thin toner layer will be described.

The toner is caused to fly by placing a counter electrode facing the thin toner layer, applying a voltage depending on image information between the pixel electrode plate and the counter electrode, and using an electric field generated between the two electrodes. This will be explained based on FIG.

A pixel signal corresponding to image information from the driver circuit is input to the gate electrode of the field effect transistor 4, and the pixel electrode 3 is grounded.

In the specific example shown in this figure, a cylindrical electrode is used as the other electrode (the counter electrode 18 facing the pixel electrode) for forming the electric field necessary for the toner to fly.

An appropriate bias voltage is applied to the cylindrical electrode 18. The cylindrical electrode 18 is rotated so as to maintain the facing position at the position where the cylindrical electrode I8 and the pixel electrode plate 1 are closest to each other, and is provided so as to move horizontally relative to the pixel electrode plate 1. It is being By moving the two so that no relative velocity occurs between them, the pixel electrode plate l
The electric field can be scanned over the entire surface, and the toner can be ejected from the thin toner layer on the pixel electrode plate in accordance with image information. If relative speed is provided,
An enlarged or reduced image biased in the moving direction of the electrode plate l is formed.

Further, the cylindrical electrode needs the function of receiving the flying toner and retaining it on its surface. Therefore, it is necessary to prevent the flying toner from flying toward the pixel electrode again. In the present invention, this objective is achieved by forming an insulating layer 19 on the surface of the cylindrical electrode.

Here, to explain the toner flying phenomenon, when an image signal is input to the driver circuit, a bias voltage is applied between the pixel electrode 3 and the counter electrode 18. Due to this application, an electric field is formed between the counter electrode and the pixel electrode, and at the same time,
Charge is injected into the toner particles 15 on the pixel electrode 3. Since this injected charge has a polarity opposite to that of the counter electrode 18,
A Coulomb force is generated between the toner particles 15 and the counter electrode 8, and this Coulomb force acts as a driving force for the flight of the toner particles. The toner particles can then fly in the electric field.

When the thus-flying toner reaches the counter electrode, if there is no insulating layer, charges with a polarity opposite to that on the pixel electrode side are injected from the counter electrode again, so that the toner starts flying again. Therefore, in the present invention, by providing an insulating layer on the opposing electrode side, injection of charges from the opposing electrode is prevented and re-flying is prevented.

Any known insulating layer can be used as the insulating layer, and an insulating thermoplastic resin or thermosetting resin may be coated on the surface of the conductive counter electrode to a thickness of 0.5 to 50 μm. When the electrode is a conductive metal, it can be oxidized to form an oxide film of 0.2 to 20 μm to form an insulating layer.

The toner image thus formed on the surface of the insulating layer of the counter electrode is transferred onto recording paper by known means such as corona transfer, electrode roller transfer, etc., and then fixed to obtain a hard copy.

Further, the residual toner on the surface of the insulating layer of the counter electrode is cleaned by a known cleaning means such as blade cleaning, fur brush cleaning, etc., and one process is completed.

In the specific example described above, a cylindrical counter electrode was used, but it goes without saying that a plate-shaped electrode similar to the pixel electrode plate may be used as long as it has an insulating layer.

Furthermore, when providing the insulating layer on the surface of the counter electrode as described above, the recording paper itself can also be used as the insulating layer. In this case, it is also desirable that the step of transferring the toner image formed on the surface of the insulating layer of the counter electrode onto the recording paper can be omitted, and the image forming process can be simplified. When using this recording paper as an insulating layer, it can be used for normal thin (tsubo 140 g/m) or thick (tsubo 140 g/m)
og/m) Any plain paper can be used, but it is insulated to have a volume resistance of 1013 Ωcm or more so that the toner particles flying onto the paper and being retained can completely prevent charge injection from the counter electrode. It may also be recording paper. In this case, the insulation processing may be a processing method that is known per se. For example, resin such as styrene-acrylic copolymer, styrene resin, acrylic resin, polyethylene resin, polyester resin, etc. is used together with clay, silica, etc. This can be done by coating on one or both sides.

As described above, the present invention performs image formation using the toner particle flying phenomenon. As described above, carrier charges are injected from the pixel electrode, and this flight is caused by the Coulomb force caused by the resulting carrier injection charges.

Therefore, as toner particles, carriers are efficiently injected from the pixel electrode, and the injected carriers are
It is desirable to have toner particles only on a specific pixel in order to form a good image. For this reason, in the present invention, it is desirable to use a toner containing a high concentration of a charge transport substance. Specifically, it varies depending on the type of charge transporting substance and binder resin used, but generally 30 to 10 parts per 100 parts by weight of binder resin.
It is desirable to use it with a 0 heavy view type O amount ratio. When the charge transporting substance is used in such a high concentration ratio, the mobility of the charge carriers in the toner is high, and charge injection from the pixel electrode to the toner can be performed satisfactorily. Moreover, since the mobility tends to increase in the direction in which the electric field is formed, charge injection between toner particles becomes possible, and this also applies when toner particles are held in multiple layers on the pixel electrode surface. Charge can be injected into all toner particles on the electrode. Then, the mobility of the toner particles still acts as an injection barrier between the toner particles in the direction other than the direction in which the electric field is formed, suppressing the injection of charge, and as a result, the toner particles fly faithfully to the pixel electrode signal. It becomes possible.

As the charge transport material suitably used in the toner of the present invention, any material capable of transporting holes or transporting electrons can be used. Specifically, hole transfer types such as hydrazone derivatives, pyrazoline derivatives, oxadiazole derivatives, triphenylamine derivatives, and styryl derivatives, and electron transfer types such as nitro-substituted fluorenone derivatives, naphthoquinone derivatives, and anthraquinone derivatives are suitable. used for.

Of course, both of these types are selected depending on the polarity of the voltage applied to the pixel electrode; the hole transfer type is used when a voltage of 10 is applied, and the electron transfer type is used when a voltage of - is applied. Ru.

As the fixing binder resin used in the toner, those known per se can be used, and for example, styrene-acrylic copolymers, styrene resins, acrylic resins, polyester resins, etc. can be suitably used.

The toner is prepared in a manner known per se, for example, by adding an appropriate amount of charge transport material to a resin and kneading, grinding, or classifying, or by uniformly dispersing or dissolving the resin and charge transport material during dissolution. can be prepared by dissolving and spraying.

It is preferable that the toner particles generally have a particle size of 5 to 50 μm, and it is of course possible to add silica as a toner modifier and a coloring agent in necessary amounts as necessary.

(Effects) According to the present invention, completely different from conventional image forming methods,
By using a method in which toner is formed as a thin layer on the pixel electrode and is ejected from pixel to pixel according to image information,
Digital images can be easily formed. Moreover, if the insulating layer formed on the counter electrode is made of recording paper, a toner image can be formed as if using a thermal transfer method.

[Brief explanation of drawings]

Figure 1 is a diagram showing the entire electrode plate used in the present invention, Figure 2 is a diagram showing the entire electrode plate used in the present invention.
and FIG. 3 are diagrams for explaining the image forming method of the present invention. l...Pixel electrode plate 3...Pixel electrode 10...Magnetic sleeve 12...Developer 13...Toner thin layer 15...Toner particles 18...Counter electrode 19...Insulating layer

Claims (2)

[Claims] (1) A thin toner layer is formed on a pixel electrode plate, a counter electrode is placed opposite to the thin toner layer via an insulating layer, and an electric field is generated between the pixel electrode plate and the counter electrode according to image information. 1. An image forming method comprising applying a voltage to inject charges into toner particles, and selectively flying the toner particles to form a toner image on an insulator. (2) The method according to claim 1, wherein the toner contains a charge transport substance in a binder at a high concentration.