JPH0483658A - Toner jet-type image forming device - Google Patents

Abstract

PURPOSE:To prevent the adhesion of a toner on the rear surface of an aperture electrode body to stably obtain a high image quality for a long time by providing an electrode arrangement consisting of reference electrodes alternating with alternating electrodes and a means for applying an alternating voltage to the reference electrodes and the alternating electrodes. CONSTITUTION:A positively electrified toner from a toner cloud supply device 14 is held in a space on the rear surface of an aperture electrode body 1 in the vicinity of the aperture out of contact with the aperture by the balance between the diffusion force of the toner and an inhibiting force from the rear surface of the aperture electrode body 1. In the aperture 6 provided in a control electrode 5, an electric line of force is formed from the rear surface to the top surface. The positively electrified toner is led out from the rear surface to the top surface to fly onto a substrate by an electric field formed by a back electrode 11. The toner is held thereon to form an image. A fly electric field by the back electrode 11. is shieled by applying the same electric potential as a reference electrode 3 or a positive voltage to the control electrode 5 of the aperture 6 corresponding to a non-image part, or an electric line of force from top surface to the rear surface is formed in the aperture 6. In this manner, the toner is prevented from passing through the aperture 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a toner jet image forming apparatus that forms an image by depositing toner on a recording medium.

[Prior Art] Conventionally, an image recording apparatus that controls passage of toner particles through an aperture and obtains an image on a support by applying an image signal to an electrode having an aperture is disclosed in U.S. Pat. No. 3,689,935.
proposed in the specification.

This proposal consists of a continuous conductor layer (reference electrode) on one side with an insulator layer in between, and multiple conductive layers (control electrodes) insulated from each other on the other side. an aperture electrode body having at least one row of apertures extending through the three layers for each control electrode; means for selectively applying a potential between the control electrode and the reference electrode; and means for moving the support and the aperture electrode relative to each other to position the support in the particle flow path.

[Problems to be Solved by the Invention] However, in the above configuration, some of the charged toner particles supplied near the aperture do not pass through the aperture and adhere to and accumulate on the reference electrode due to image force, eventually blocking the aperture. The electric charge disturbs the electric field,
As a result, it has been difficult to stably output high-quality images over a long period of time.

The present invention has been made to solve the above-mentioned problems, and its purpose is to form an image that can stably obtain high image quality over a long period of time by preventing toner from adhering to the back surface of the aperture electrode body. The goal is to provide equipment.

[Means for Solving the Problems] The toner jet image forming apparatus of the present invention includes a plurality of control electrodes arranged on a surface, and a surface on the toner supply side of the control electrodes that is insulated from the control electrodes and arranged with the control electrodes. A toner jet image forming apparatus that is composed of reference electrodes arranged in parallel, and that each control electrode has an aperture electrode body having an aperture that penetrates the control electrode and the reference electrode, and that forms an image by depositing toner on a recording medium. In this embodiment, the structure includes an electrode array in which alternating current electrodes are arranged alternately with the reference electrode, and means for applying an alternating current voltage to the reference electrode and the alternating current electrode.

[Function] According to the present invention having the above configuration, by applying an AC electrode between the reference electrode and the AC electrode, periodic inequalities are created both spatially and temporally on the back surface of the aperture electrode body. An alternating electric field is formed. As a result, the charged l·ner as a whole receives a force that moves it away from the back surface of the aperture electrode body, and is prevented from adhering and depositing on the back surface of the aperture electrode by this so-called electric field curtain.

[Example] Hereinafter, an example embodying the present invention will be described with reference to the drawings.

As shown in FIGS. 1 and 2, the aperture electrode body 1 has a reference electrode 3 and an AC electrode 4 on the toner supply source side of the insulating layer 2, and a control electrode 5 on the support side. 3. Apertures 6 penetrating the control electrode 5 are formed in multiple rows corresponding to the width of the support.

In FIG. 1, on the reference electrode 3 side of the aperture electrode body 1, there is a toner cloud supply device 14 that supplies charged toner to the vicinity of the aperture 6. A back electrode 11 is disposed on the control electrode 5 side of the aperture electrode body 1 and is conveyed while being in contact with the support 10 .
is located.

The reference electrode 3 and the AC electrode 4 are connected to an AC power source 7 that applies an AC voltage. Each control electrode 4 is connected to a control voltage drive circuit 8 that generates a voltage based on an image signal. The back electrode 11 is connected to a negative high voltage power source 12 .

When an alternating current voltage is applied between the alternating current electrode 4 and the reference electrode 3 in the above configuration, an unequal alternating electric field is formed on the surface (back surface) of the aperture electrode body 1 on the toner cloud supply source side. The charged toner particles existing in this surface space vibrate along the curved lines of electric force 9, and are subjected to centrifugal force in the convex direction of the lines of electric force every half cycle.

Furthermore, due to the phase lag in their vibrations, toner particles receive a repulsive force from the electrode in areas where the electric field is large near the electrode.
Areas far from the electrode where the electric field is weak receive an attractive force towards the electrode. When averaged over time, this force is applied in a direction tangent to the line of force and away from the electrode, and is called a gradient force. Therefore, the positively charged toner supplied from the toner cloud supply device 14 is brought into contact with the space above the back surface of the aperture electrode body 1 in the vicinity of the aperture due to the balance between its spreading force and the blocking force from the back surface of the aperture electrode body 1. is held in

At this time, when a negative voltage is applied to the control electrode 5 in accordance with the image signal, lines of electric force are formed in the aperture 6 of the applied control electrode 5 from the back surface to the front surface, and the positively charged toner is is pulled out from the back surface to the front surface, and further flies onto the support and is held by the flying electric field formed by the back electrode 11 to form an image.

By applying the same potential as the reference electrode 3 or a positive voltage to the control electrode 5 of the aperture 6 corresponding to the non-image area, the flying electric field caused by the back electrode 11 can be shielded, or the electric field flowing from the front surface to the back surface can be applied to the control electrode 5 of the aperture 6 corresponding to the non-image area. By forming lines of force, toner is prevented from passing through the aperture 6.

By repeating this process while transporting the support 10, a toner image is formed on the entire surface of the support 10, and finally, by fixing it with the fixing device 13, an image can be obtained on the support 10.

In the above embodiments, a positively charged toner is used, but the toner may be negatively charged. However, in that case, the signs of the voltages applied to the control electrode 5 and the back electrode 11 will also be reversed.

Furthermore, the arrangement of the reference electrode 3 and AC electrode 4 for generating an electric field curtain on the back surface of the aperture electrode body 1 is not limited to that shown in FIG. The reference voltage is placed! Any configuration may be used as long as the AC electrodes 3 and 4 are arranged alternately.

[Effects of the Invention] As is clear from the detailed description above, according to the present invention, in a toner jet image forming apparatus that forms an image by depositing toner on a recording medium, alternating current electrodes are arranged alternately with reference electrodes. Since the electrode array and means for applying an AC voltage to the reference electrode and the AC electrode are provided, charged toner does not adhere to or accumulate on the back surface of the aperture electrode body, thereby preventing the aperture from clogging.
It is possible to output stable images over a long period of time without causing disturbances in the electric field.

[Brief explanation of the drawing]

1 to 4 show embodiments embodying the present invention, FIG. 1 is a schematic diagram showing the configuration of a toner jet image forming apparatus, and FIG. 2(a) shows an aperture electrode. 2(b) is a sectional view of the same, FIG. 2(e) is a back view of the same, and FIGS. 3 and 4 show other embodiments of the electrode array. It is a diagram. In the figure, 1 is an aperture electrode body, 2 is an insulating layer, 3 is a reference electrode, 4 is an AC electrode, 5 is a control electrode, 6 is an aperture, and 7
14 is an AC power supply, and 14 is a toner cloud supply device.

Claims (1)

[Claims] 1. Consisting of a plurality of control electrodes arranged in one plane and a reference electrode on the toner supply side of the control electrodes, insulated from the control electrodes and arranged parallel to the plane on which the control electrodes are arranged, In a toner jet image forming apparatus that is provided with an aperture electrode body having an aperture that penetrates the control electrode and a reference electrode for each control electrode and forms an image by depositing toner on a recording medium, alternating current electrodes are arranged alternately with the reference electrode. What is claimed is: 1. A toner jet image forming apparatus comprising: an electrode array; and means for applying an alternating current voltage to a reference electrode and an alternating current electrode.