JPS63100480A - Corona discharger - Google Patents

Abstract

PURPOSE:To correspond to an operation for a long time, by providing a means which moves at least either a discharge electrode, or a discharge element in a direction orthogonal to the longitudinal direction of the discharge element, and also to set a distance between the discharge electrode and the surface of a dielectric at a constant length. CONSTITUTION:The means is provided which moves either at least the discharge element 1 or the discharge electrode 2 in the direction orthogonal to the longitudinal direction of the discharge element, and also to hold the distance between the surface of the dielectric 4 and the discharge electrode 2 in constant invariably. In other words, by arranging the discharge electrode 2 evading a part of the surface of the dielectric impaired by spattering, the influence of deterioration in the surface of the dielectric can be prevented. Also, for the deterioration in the discharge electrode, a discharge electrode winding means consisting of a pulley 21 on which the discharge electrode 2 is wound, a pulley 22 to wind a deteriorated discharge electrode, and a driving means (for example, a motor) 20 to drive the winding pulley 22, is provided.

Description

Detailed Description of the Invention (Technical Field) The present invention comprises a discharge element comprising a dielectric and an internal electrode covered with the dielectric, and a discharge electrode installed apart from the surface of the dielectric. This invention relates to a corona discharge device. This type of corona discharge device is used as a charging removal device for electrostatic recording devices, electrophotographic devices, etc., and can also be applied to various fields as a discharge device and an ion source.

(Prior Art) Conventionally, in electrophotographic devices and other electrostatic image devices, corona discharge devices that apply a high voltage to a wire electrode to cause corona discharge have been widely used.

However, in the corona discharge device, the wire electrode is contaminated with paper powder, toner, etc., or the electrode surface is oxidized.
The problem was uneven discharge due to scratches.

Further, since a metal casing is required, it is difficult to downsize the device.

In order to solve this problem, solid state discharge devices are being put into practical use that are superior in terms of miniaturization, ease of maintenance, and the like.

The solid state discharge device is composed of an internal electrode covered with a dielectric and a discharge electrode disposed in contact with the surface of the dielectric, and an alternating current voltage is applied between the internal electrode and the discharge electrode. This causes creeping corona discharge.
Because the alternating current electric field causes paper powder, toner, etc. near the t pole to be charged and repelled! It is characterized by the fact that uneven discharge occurs due to dirt on the electrode. However, since the discharge electrode is in contact with the dielectric surface, if moisture is adsorbed on the dielectric surface, uneven discharge occurs, and the environment, especially the relative The problem is that it is easily affected by humidity.

In order to improve this problem, the present applicant has already proposed a corona discharge device having a structure in which the discharge electrode is installed apart from the dielectric surface. According to this structure, uniform discharge that is not affected by changes in the environment can be obtained without impairing the feature of miniaturization of the discharge device. However, the problem of deterioration of the dielectric surface of the discharge electrode and the discharge region over time due to oxidation, sputtering, etc. due to discharge has not yet been resolved.

(Objective) It is an object of the present invention to provide a solid-state discharge device that eliminates the above-mentioned problems and provides stable discharge characteristics over a long period of time.

(Structure) For this purpose, the present invention provides a discharge element consisting of a dielectric and an internal electrode covered with the dielectric, and at least one of the discharge electrodes, which is perpendicular to the longitudinal direction of the discharge element and parallel to the dielectric surface. It is characterized by having means for moving in a direction in which the distance from the discharge electrode is constant.

Hereinafter, the present invention will be specifically explained based on examples.

FIG. 1 is a diagram for explaining one embodiment of the present invention.

In the figure, a discharge element 1 is composed of an internal electrode 3, a dielectric 4, and an insulating substrate 5, and a discharge electrode 2 is arranged at a certain distance from the surface of the dielectric 4. Further, the discharge electrode 2 and the charged object 6 are arranged in parallel with each other at a predetermined distance as shown in the figure.

Further, the drive circuit of the corona discharge device is shown as an example composed of a high-voltage AC power supply 10 and a double voltage rectifier circuit 13, and the high-voltage AC power supply 10 is further composed of a low-voltage drive circuit 11 and a step-up transformer 12.

The output terminals of the high voltage AC power supply 10 are connected to the discharge electrode 2 and the internal electrode 3, respectively, and similarly, the double voltage rectifier circuit 1
3 are also connected as shown in the figure.

Furthermore, a charging current detection circuit 14 is connected between the illustrated point A and the ground.
is connected, and the configuration signal is sent to the constant current control circuit 15.
By applying feedback to the low voltage drive circuit 11, the charging current is controlled so that a constant charging current is always obtained.

When the corona discharge device is driven with the above-described configuration, uniform discharge can be obtained without being affected by environmental changes, but if the surfaces of the discharge electrode 2 and dielectric 4 deteriorate over time, local discharge may occur. Streamer discharge occurs and uniformity is lost.

The deterioration of the dielectric surface is thought to be mainly caused by sputtering during discharge, and when the surface is roughened by sputtering, discharge tends to concentrate locally, causing a transition from glow discharge to streamer discharge.

Therefore, the discharge becomes non-uniform and the amount of ozone generated also increases. In addition, since moisture tends to adhere to the dielectric surface,
It is greatly affected by the surrounding environment, especially relative humidity, and stable discharge cannot be obtained.

Therefore, according to the present invention, the discharge element 1 and the discharge electrode 2
This problem can be solved by providing means for moving at least one of the discharge electrodes in a direction perpendicular to the longitudinal direction of the discharge element and in a direction that keeps the distance between the surface of the dielectric 4 and the discharge electrode 2 constant.

That is, if the discharge electrode 2 is arranged avoiding a part of the dielectric surface damaged by sputtering, it will not be affected by the deterioration of the dielectric surface.

Further, deterioration of the discharge electrode can be solved by means as shown in FIG.

That is, the discharge electrode winding is composed of a pulley 21 around which the discharge electrode 2 is wound, a pulley 22 for winding up the deteriorated discharge electrode, and a driving means (for example, a motor) 20 for driving the winding pulley 22. This is achieved by taking measures.

The driving means 20 receives the winding instruction signal and winds up the discharge electrode by a necessary length in accordance with the longitudinal length of the discharge element 1. Thereby, there is no need to clean or replace the discharge electrode 2, and service costs can be significantly reduced.

FIG. 3 shows another embodiment of the present invention, in which the discharging element 1 is disposed perpendicularly to the object 6 to be charged. In this case as well, the above-mentioned means can be applied in the same manner.

Figure 4 shows the results of experiments conducted to confirm the effects of the present invention. The straight line ■ shows the characteristics. A corona discharge device whose discharge electrodes and dielectric material have deteriorated due to continuous operation is the same as a new one! It is clear from the figure that a large amount of ozone is generated to obtain current.

Here, when the discharge element was moved and a dielectric surface that had not deteriorated was used, the characteristics improved as shown by the straight line (■). Furthermore, when the dielectric remained deteriorated and the discharge electrode was wound up and a new tfM was used, it became like a straight line (■).

When I replaced both, the characteristics returned to their original state.

As is clear from the above, in order to eliminate deterioration due to discharge, it is necessary to renew both the discharge electrode and the dielectric, and the present invention has made it possible to achieve this.

(Effects) The present invention is as described above, and according to the present invention, long-term operation can be achieved, maintenance-free operation can be achieved, and there is no need to clean or replace the discharge electrode, so service costs can be reduced. .

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the entire corona discharge device according to one embodiment of the present invention, Fig. 2 is a diagram showing a winding mechanism of a discharge electrode, Fig. 3 is a schematic diagram according to another embodiment, and Fig. 4 These are characteristic diagrams showing the relationship between the charging current and the amount of ozone generated under various conditions. DESCRIPTION OF SYMBOLS 1... Discharge element, 2... Discharge electrode, 4... Dielectric, 20.21.22... Discharge electrode winding means. 1st diagram Wharf 2nd section 3rd section 4th factor charging f-shin Ic -

Claims (2)

[Claims] (1) In a corona discharge device configured with a discharge element consisting of a dielectric and an internal electrode covered with the dielectric, and a discharge electrode installed apart from the surface of the dielectric, the discharge electrode and the discharge A corona discharge device comprising means for moving at least one of the elements in a direction perpendicular to the longitudinal direction of the discharge element and in which the distance between the discharge electrode and the dielectric surface is constant. (2) Claim (1) characterized in that it has a reel on which the discharge electrode is wound, a reel for winding up the used discharge electrode, and a reel driving means for winding up the discharge electrode. ) The corona discharge device described in item 2.