JP2850503B2 - Toner jet type image forming apparatus - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner jet type image forming apparatus for forming an image by attaching toner to a recording medium.

2. Description of the Related Art Conventionally, an image recording apparatus that controls the passage of toner particles through an aperture by applying an image signal to an electrode having an aperture to obtain an image on a support has been proposed in US Pat. No. 3,689,935. I have. In this proposal, a conductor layer (reference electrode) which is continuous on one side with an insulator layer interposed therebetween and a plurality of conductive layers (control electrodes) which are insulated from each other on the other side are provided. An aperture electrode body having at least one row of apertures penetrating three layers for each control electrode, means for selectively applying a potential between the control electrode and the reference electrode, and an aperture provided by the applied potential And means for projecting charged particles so as to modulate the flow of the toner particles passing therethrough, and means for positioning the support in the particle flow path by relatively moving the support and the aperture electrode body.

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

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an image forming apparatus capable of stably obtaining high image quality for a long time by preventing toner adhesion on the back surface of an aperture electrode body. It is to provide a device.

Means for Solving the Problems A toner jet image forming apparatus according to the present invention includes a plurality of control electrodes arranged on one surface and a surface on which the control electrodes are insulated from the control electrodes on the toner supply side of the control electrodes. A toner jet type image forming apparatus, comprising: a reference electrode arranged in parallel; an aperture electrode body having an aperture penetrating the control electrode and the reference electrode for each control electrode; and adhering toner to a recording medium to form an image. In the above structure, there is provided an electrode array in which AC electrodes are alternately arranged with the reference electrodes, and means for applying an AC voltage to the reference electrodes and the AC electrodes.

[Action] According to the present invention having the above-described configuration, by applying an AC electrode between the reference electrode and the AC electrode, the spatial and temporal periodic inequality is formed on the back surface of the aperture electrode body. An alternating electric field is formed. As a result, the charged toner is subjected to a force to keep it away from the rear surface of the aperture electrode body as a whole, and does not adhere to and accumulate on the rear surface of the aperture electrode due to the so-called electric field curtain.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 and 2, the aperture electrode body 1 has a reference electrode 3, an AC electrode 4,
A control electrode 5 is provided on the side of the support, and a large number of apertures 6 penetrating the insulating layer 2, the reference electrode 3, and the control electrode 5 are formed in a line in the width of the support.

In FIG. 1, a toner cloud supply device 14 for supplying charged toner to the vicinity of the aperture 6 is provided on the reference electrode 3 side of the aperture electrode body 1. On the control electrode 5 side of the aperture electrode body 1, a back electrode 11 which is transported while being in contact with the support 10
Is disposed, and a fixing device 13 is disposed at the destination of the support 10.

The reference electrode 3 and the AC electrode 4 are connected to an AC power supply 7 for applying an AC voltage. Each control electrode 4 is connected to a control voltage drive circuit 8 that generates a voltage according to an image signal. The back electrode 11 is connected to a negative high-voltage power supply 12.

When an AC voltage is applied between the AC electrode 4 and the reference electrode 3 in the above configuration, an uneven 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 the space on the surface vibrate along the curved lines of electric force 9 and receive a centrifugal force in the convex direction of the line of electric force every half cycle.

Further, the toner particles receive a repulsive force from the electrode where the electric field is large near the electrode due to the phase delay of the vibration, and receive an attractive force to the electrode where the electric field is far away from the electrode and where the electric field is weak. When this force is averaged over time, the force comes into contact with the force line and moves away from the electrode, and is called a so-called gradient force. Therefore, the positively charged toner supplied from the toner cloud supply device 14 is brought into non-contact with the vicinity of the aperture in the space on the back surface of the aperture electrode body 1 due to the balance between the force to spread and the stopping force from the back surface of the aperture electrode body 1. Is held.

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

Applying the same potential or a positive voltage to the control electrode 5 of the aperture 6 corresponding to the non-image portion to shield the flying electric field by the back electrode 11 by applying the same potential or a positive voltage to the control electrode 5 By forming the force lines, the 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, an image can be obtained on the support 10 by being fixed by the fixing device 13.

In the above embodiment, the example of the positively charged toner is used, but the toner may be negative. However, in this case, the signs of the voltages applied to the control electrode 5 and the back electrode 11 are also opposite to the above.

Further, the arrangement of the reference electrode 3 and the AC electrode 4 for generating an electric field curtain on the back surface of the aperture electrode body 1 is not limited to FIG. 2, but the reference electrode 3 around the aperture 6 as shown in FIGS. And the reference electrode 3 and the AC electrode 4 may be arranged alternately.

[Effects of the Invention] As is clear from the above, according to the present invention, in a toner jet type image forming apparatus for forming an image by attaching toner to a recording medium, an AC electrode is alternately arranged with a reference electrode. Since the electrode array and the means for applying an AC voltage to the reference electrode and the AC electrode are provided, the charged toner does not adhere and accumulate on the back surface of the aperture electrode body, the aperture is not clogged, and the electric field is not disturbed for a long time. It is possible to continuously output a stable image.

[Brief description of the drawings]

FIGS. 1 to 4 show an embodiment embodying the present invention. FIG. 1 is a schematic view showing a configuration of a toner jet type image forming apparatus, and FIG. 2 (a) is an aperture electrode. FIG. 2 (b) is a cross-sectional view of the body, FIG. 2 (c) is a rear view thereof, and FIGS. 3 and 4 show another embodiment of an electrode array. FIG. 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, 7
Is an AC power supply, and 14 is a toner cloud supply device.

Claims (1)

(57) [Claims] 1. A control electrode comprising: a plurality of control electrodes arranged on one surface; and a reference electrode disposed on a toner supply side of the control electrode and insulated from the control electrode and arranged in parallel with the surface on which the control electrodes are arranged. A toner jet type image forming apparatus comprising an aperture electrode body having an aperture penetrating a control electrode and a reference electrode for each, and forming an image by attaching toner to a recording medium, wherein an electrode array in which alternating current electrodes are alternately arranged with the reference electrode And a means for applying an AC voltage to the reference electrode and the AC electrode.