JPH06124792A - Static eliminating electrode - Google Patents

Abstract

PURPOSE:To reduce cost, and also improve static eliminating or electrifying performance while facilitating manufacture by reduction of the number of part items and simplification of a structure. CONSTITUTION:Plural electrode pieces 20 are implanted at prescribed intervals in a printed board 21, and are connected respectively electrically to electrically conductive patterns 22 on the printed board, and the printed board and an electrical conductor 23 upon which voltage is impressed are buried oppositely in resin 24 mixed with fine powder while holding a prescribed interval. When an electrostatic capacity coupling type is formed, an electrostrictive material having a specific dielectric constant larger than a specific dielectric constant of the resin is used as the fine powder, and when a resistance coupling type is formed, metallic fine power or carbon fine powder or the like having resistivity smaller than resistivity of the resin is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a destaticizing electrode used for destaticizing or charging.

[0002]

2. Description of the Related Art FIGS. 1 and 2 show an example of a conventional electrostatic capacity coupling type static eliminating electrode. This static elimination electrode is a high voltage cable 1
On the outer circumference of the insulation coating 3 covering the core wire 2 of
Attach a large number of conductive rings 5 to which
The conductive ring 5 and the base ends of the electrode needles 4 are embedded in an insulating resin 7 such as urethane in the insulating body 6 in order to prevent a creeping discharge or the like generated when a high voltage is applied. The tip of 4 is projected from the insulating body 6. In addition, 8 is a supporter, 9 is the supporter 8
This is a ground plate held by the insulating body 6 at a constant distance. According to this static elimination electrode, the electrode needle 4
In addition to the problems that the conductive ring 5 is required for each one, the number of assembling steps is large, and the miniaturization is difficult, there are also the following problems.

That is, the static elimination electrode having such a structure can be represented by an equivalent circuit as shown in FIG. Here, the core wire 2 and the electrode needle 4 of the high-voltage cable 1 are connected by the insulating coating 3 to obtain a relative permittivity necessary for static elimination performance, and the conductive ring 5 to obtain an area necessary for capacitive coupling. A capacitance Cp is formed between the electrode 2 and the electrode needle 4. This coupling capacitance Cp (pF) has a relative permittivity of the insulating coating 3 of ε, a length of the conductive ring 5 of L (mm), and an outer diameter of D.
(Mm) and the inner diameter are d (mm), they are given by the following equation. Cp = (241 ・ L ・ ε) / (F ・ 10000) where F = log (D / d)

In this static elimination electrode, an insulating coating 3 is applied to the outer circumferences of the core wire 2 and the conductive ring 5, but the electrode needle 4
There is a capacitance Cg between the ground and the ground, and an insulation resistance Rg between the electrode needle 4 and the ground. These Cg and Rg have elements that reduce the static elimination performance.

That is, when the static elimination electrode is used for a long time, dust adheres to the insulating body 6. This dust deteriorates the insulation resistance Rg under the influence of the adhered state and temperature. This deterioration is the same as when the conductive ring is further wound around the outer periphery of the insulating resin 7 (in addition to the conductive ring 5 on the inner side, a virtual conductive ring is formed on the outer side of the insulating body 6). And the electrostatic capacitance Cg between the grounds increases. In such a state, the impedance between the electrode needle 4 and the ground is a parallel impedance of Cg and Rg, and therefore decreases as Cg increases, and the voltage Vp applied to the electrode needle 4 also decreases. Therefore, the electrode needle 4
If the high voltage Hv to be applied to is constant, the effective static elimination current also decreases.

The static elimination electrode shown in FIGS. 4 and 5 is disclosed in Japanese Patent Application Laid-Open No. 2-123698.
In order to solve the above-mentioned problems of the static elimination electrode having the structure shown in FIGS. 1 and 2, the present applicant has previously proposed.
The static elimination electrode has a ceramic dielectric element 11 fitted in a mounting hole of a conductive substrate 10,
The base end portion of the electrode needle 12 is implanted in the hole of, and the base end portions of the conductive substrate 10, the ceramic dielectric element 11 and the electrode needle 12 are generated when a high voltage is applied in the same manner as above. In order to prevent creeping discharge and the like, it is embedded in an insulating resin 7 such as urethane or epoxy in the insulating body 6.

FIG. 6 shows an equivalent circuit of the static elimination electrode shown in FIGS. 4 and 5. The conductive substrate 10 and the electrode needle 12 are capacitively coupled by the ceramic dielectric element 11, and the ceramic dielectric element 11 obtains the relative permittivity and the coupling area necessary for the static elimination performance to obtain the conductive substrate 10 and the electrode needle 12. A capacitance Cp is formed between the and. This coupling capacitance Cp (pF)
Is the dielectric constant of the ceramic dielectric element 11 is ε, the thickness of the conductive substrate 10 is L (mm), the ceramic dielectric element 1
When the outer dimension of 1 is D (mm) and the inner dimension is d (mm), it is given by the following equation as in the above. Cp = (L ・ 241 ・ ε) / (F ・ 10000) where F = log (D / d)

However, the respective electrode needles 12 of this static elimination electrode
Has a structure in which it is individually implanted in the ceramic dielectric element 11 and is surrounded by it. Therefore, the coupling capacitance C due to the ceramic dielectric element 11 is provided between the electrode needle 12 and the ground.
An electrostatic capacitance Cg is formed via p, that is, this electrostatic capacitance Cg is generated between the conductive substrate 10 supporting the ceramic dielectric element 11 and the ground, and therefore does not directly affect the electrode needle 12. Therefore, when the insulation resistance of the electrode needle 12 deteriorates, the electrode needle 12 receives only the amount of resistance decrease due to the deterioration and is not affected by the capacitance Cg.
The tendency that the effective static elimination current decreases due to the contamination of 2 and its surroundings decreases. However, despite these advantages,
About each electrode needle 12 Ceramic dielectric element 1
1 is prepared, and the electrode needles 12 are planted one by one, and the ceramic dielectric element 11 is further attached to the conductive substrate 1.
Since it must be fitted in the mounting hole of 0, the use of the ceramic dielectric element 11 makes it relatively expensive, and
Many man-hours for assembly.

Further, in the conventional resistance-coupling type static eliminator or charging electrode, each of a plurality of electrode needles is connected in parallel to a common electric conductor via a resistance element. Was time-consuming and the workability in manufacturing was poor.

[0010]

SUMMARY OF THE INVENTION In view of the above-mentioned problems caused by the conventional static elimination or charging electrodes, an object of the present invention is to reduce the number of parts and simplify the structure to facilitate the manufacture and reduce the cost. Another object is to provide a destaticizing electrode having high static elimination or charging performance.

[0011]

According to the present invention, in the case of a capacitive coupling type destaticizing electrode, these are capacitively coupled between an electrode element and an electric conductor to which a voltage is applied. A resin is interposed to maintain a constant interval, and a large number of fine powders having a relative dielectric constant larger than the relative dielectric constant are mixed into this resin to increase the relative dielectric constant of the resin. For example, the relative permittivity of urethane resin, epoxy resin or the like which is usually used is about 3 to 5, but it is set to 10 to 200. As the fine powder to be mixed, for example, fine powder of an electrostrictive material such as barium titanate, zircon / lead titanate, and lead niobate is used.

In the case of a resistance-coupling type destaticizing electrode, a constant distance is maintained between the electrode element and the electric conductor to which a voltage is applied by interposing a resin for resistance-coupling them. A large number of fine powders having a resistivity smaller than that resistivity are mixed in this resin. For example, the resistivity of urethane resin, epoxy resin, etc. is on the order of 10 ¹² Ω / cm, but this is greatly reduced to about 20 MΩ / cm to 500 MΩ / cm. Fine powders to be mixed include gold, silver,
In addition to fine metal powders such as copper, fine carbon powders are also conceivable.

In both of the capacitance type and the resistance coupling type, a plurality of electrode elements are arranged at regular intervals to face one electric conductor, and the electric conductor and a part of the electrode element are made into fine powder. It is possible to form an integrated structure in which the resin is mixed and embedded at a predetermined interval. As a preferred specific form thereof, as in the embodiment shown in FIGS. 7 to 9, a plurality of electrode elements 20 are planted in a printed circuit board 21 at a predetermined interval, and each electrode element 20 is printed. 21. The printed circuit board 21 and the electric conductor 23 to which a voltage is applied are electrically connected to the conductive patterns 22 formed on the printed circuit board 21 and are opposed to each other in a resin 24 mixed with fine powder with a predetermined interval. The structure is such that it is embedded and a part of the electrode element 20 is projected from the resin 24. In this case, by selecting the material of the fine powder to be mixed from the above, it is possible to decide whether to use the capacitance type or the resistance coupling type structure. For either the capacitance type or the resistance coupling type structure, However, the manufacturing method is the same, the structure of the finished product can be the same, and the charge removal performance or the charging performance can be adjusted arbitrarily depending on the mixing amount.

If fine powders having different particle sizes are mixed in the resin,
A fine resin molding structure can be formed, and electrical characteristics in the resin are more stable.

[0015]

According to the decharging electrode of the present invention, when the electrostatic charge type is used in the form shown in FIGS. 7 to 9, it can be represented by the same equivalent circuit as in FIG. There is little tendency to decrease. Here, the relative permittivity of the resin (dielectric) 24 mixed with fine powder is ε, the area of the conductive pattern 22 facing the electric conductor 23 is E (mm ² ), and the thickness of the resin 24 is t (mm ), The coupling capacitance Cp (p
F) is given by the following equation. Cp = (0.0885 · ε · E) / (t · 10)

One trial calculation according to this formula is that a urethane resin having a relative permittivity of about 3 to 5 is used as the resin 24, and barium titanate powder is mixed into the urethane resin to raise the relative permittivity ε to 50. The area E of the conductive pattern 22 is 3
6 (mm ² ) and the thickness of the resin 24 is 3 (mm), Cp = (0.0885 · 50 · 36) / 3 · 10 = 5.
It becomes 31 (PF), and it is possible to obtain a sufficient coupling electrostatic capacity as static elimination performance.

In the case of the resistance coupling type shown in FIGS. 7 to 9, the resistivity of the resin 24 mixed with fine powder is ρ, and the area of the conductive pattern 22 facing the electric conductor 23 is E ( mm ² ), and the distance between the electric conductor 23 and the conductive pattern 22 is L, the coupling resistance R can be expressed by the following equation. R = ρ ・ (L / E)

Therefore, in both of the capacitance coupling type and the resistance coupling type, the resin 24 can prevent creeping discharge at the time of applying a high voltage, and the resin 24 itself can provide the coupling capacitance necessary for the static elimination performance. Alternatively, the resistivity can be secured.

[0019]

EXAMPLES Next, examples of the present invention will be described. Figure 7
9 to FIG. 9 show examples embodied as static elimination electrodes. This static elimination electrode includes a plurality of needle-shaped electrode elements 20 on the printed circuit board 2
1 at a predetermined interval to electrically connect the base end portion of each electrode element 20 to a circular conductive pattern 22 such as a copper foil formed on the back surface of the printed board 21. The printed board 21 and the plate-shaped electric conductor 23 are connected to the spacer 2
After being assembled in an insulating body 26 having a U-shaped cross section while being opposed to each other at a predetermined interval with 5, a resin 24 such as urethane or epoxy mixed with a large number of fine powder is filled in the insulating body 26. , The printed circuit board 21 and the plate-shaped electric conductor 23 are embedded in a resin 24.
The pointed tip of 0 projects from the surface of the resin 24.

When the static elimination electrode itself is provided with a ground electrode, a pair of ground plates 28 are fixed in parallel to each other on the outer side of the insulating body 26 with a supporter 27 interposed between the tip of the electrode body 20 and the ground plate 28. To generate a discharge.

When the static elimination electrode is of the capacitive coupling type, an electrostrictive material having a relative dielectric constant larger than the relative dielectric constant (3 to 5) of the resin 24 as fine powder mixed in the resin 24, For example, fine powder of barium titanate, zircon / lead titanate, lead niobate, etc. is used and the relative permittivity is 10 to 10.
Increase to 200.

When the resistance coupling type is used, the resin 2 is used.
As a fine powder mixed in 4, the resistivity of the resin 24 (10
Gold with much lower resistivity than the order of ¹² Ω / cm),
By using fine metal powder such as silver and copper or fine carbon powder, the resistivity is significantly reduced to about 20 MΩ / cm to 500 MΩ / cm.

Although the above example has been embodied as a static elimination electrode, the present invention can be used as a charging electrode with the same structure.

[0024]

The effects of the present invention are listed below. In both cases of capacitance coupling type and resistance coupling type, the resin can prevent creeping discharge at the time of applying a high voltage, and the resin itself can increase the coupling capacity or resistivity necessary for the static elimination performance or the charging performance. Since it can be secured, a conductive ring, a ceramic dielectric element, a resistance element, etc., which are conventionally required for each electrode element, are unnecessary (for example, 1 m
With 66 electrodes arranged in the length of, the need for 66 conductive rings, ceramic dielectric elements, and resistance elements per 1 m is eliminated). Significant cost reduction can be achieved.

By selecting the material of the fine powder to be mixed, it is possible to decide whether to use the capacitance type or the resistance coupling type structure, and for both the capacitance type and the resistance coupling type structure, the manufacturing method is used. Since they are the same and the structure of the finished product can be made the same, the manufacturing efficiency is good, the electrostatic capacity type electrode manufacturing apparatus and the resistance coupling type electrode manufacturing apparatus can be shared, and the factory facilities can be rationalized.

The resin itself can secure the binding capacity or the resistivity necessary for the static elimination performance or the charging performance, and the static elimination performance or the charging performance can be arbitrarily adjusted by the amount of the fine powder mixed in the resin. It is possible to provide a stable and optimal electrode that is suitable for the intended use and usage conditions.

The size can be reduced by reducing the number of parts. Even if dust or the like adheres to the electrode element and its surroundings, the effective static elimination current is less attenuated and the static elimination performance can be maintained.

If electrode needles are implanted in a printed circuit board on which a conductive pattern is formed and this printed circuit board is embedded in a resin together with an electric conductor, mass production is easy, and at the same time, the distance between the electrode elements is small. Can be small and constant.

When fine powders having different particle sizes are mixed in the resin, a fine resin molding structure can be formed and the electrical characteristics in the resin become more stable.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view of a conventional electrostatic discharge electrode using a high voltage cable.

FIG. 2 is a transverse sectional view of the above.

FIG. 3 is an equivalent circuit diagram of the static elimination electrode.

FIG. 4 is a partially cutaway front view of a conventional electrostatic discharge electrode using a ceramic dielectric element.

FIG. 5 is a transverse sectional view of the above.

FIG. 6 is an equivalent circuit diagram of the static elimination electrode.

FIG. 7 is a vertical cross-sectional view of a static elimination electrode according to an example of the present invention.

FIG. 8 is a transverse sectional view of the above.

FIG. 9 is a back view of the printed circuit board in the static elimination electrode.

[Explanation of symbols]

 20 Electrode 21 Printed Circuit Board 22 Conductive Pattern 23 Electric Conductor 24 Resin

Claims (8)

[Claims] 1. A resin is interposed between the electrode element and an electric conductor to which a voltage is applied so as to capacitively couple them to each other so that a certain distance is maintained, and the resin has a relative dielectric constant larger than that. A destaticizing electrode, characterized in that a large number of fine powders having a relative dielectric constant are mixed. 2. The destaticizing electrode according to claim 1, wherein the dielectric constant of the resin for capacitive coupling is set to 10 to 200 by mixing the fine powder. 3. The decharged electrode according to claim 1, wherein the fine powder is a fine powder of an electrostrictive material such as barium titanate, zircon / lead titanate, and lead niobate. 4. A resin is interposed between the electrode element and an electric conductor to which a voltage is applied by resistance-coupling them to maintain a constant distance, and the resin has a resistivity smaller than the resistivity. A destaticizing electrode, characterized in that a large number of fine powders thereof are mixed. 5. The destaticizing electrode according to claim 4, wherein the resistivity of the resin for resistance coupling is set to 20 MΩ / cm to 500 MΩ / cm by mixing the fine powder. 6. A plurality of the electrode elements are arranged at regular intervals so as to face one of the electric conductors, and the electric conductors and a part of the electrode elements are arranged at a predetermined interval in a resin mixed with the fine powder. The destaticizing electrode according to claim 1 or 4, wherein the destaticizing electrode is embedded while being held. 7. A printed circuit board, wherein a plurality of the electrode elements are planted on a printed circuit board at a predetermined interval, and each electrode element is electrically connected to a conductive pattern formed on the printed circuit board. 7. The electrode according to claim 6, wherein the electric conductor and the electric conductor are oppositely embedded in a resin mixed with the fine powder at a predetermined interval, and a part of the electrode element is projected from the resin. Charging electrode. 8. The destaticizing electrode according to claim 1, wherein fine powders having different particle sizes are mixed in the resin.