JPH06243989A - Elimination of static electricity for electrified travel body - Google Patents

Abstract

PURPOSE:To provide a static electricity eliminating method for an electrified travel body by which bipolar electrification at small pitch or even a microscopic discharge scar can be eliminated. CONSTITUTION:A static electricity eliminating method for an electrified travel body is to eliminate static electricity of the electrified travel body by generating corona discharge between it and an earth electrode 2 arranged on the opposite side of the electrified travel body while impressing AC voltage on a discharge electrode 3 arranged in a noncontact condition on one side of a web shape electrified travel body 1. Assuming that a distance between the discharge electrode and the electrified travel body when it is measured on the shortest passage connecting between the discharge electrode and the earth electrode is [[d1 (mm)], and thicknesses of air and a dielectric layer interposed between the electrified travel body and the earth electrode are [d2 and 3 (mm)] respectively, and a specific dielectric constant of the dielectric layer is (epsilon), the positional relationship between the discharge electrode, the electrified travel body and the earth electrode, the thickness of the dielectric layer and a construction material are regulated so as to fall withing a range of [[8<=d1+d2+d3/epsilon<=25 and 1<=d2+d3/epsilon<=5]. At the same time, assuming that travel speed of the electrified travel body is V (m/min.), and a width of static electricity in which the static electricity of a stationary object can be eliminated is W (mm), AC voltage having a frequency of 1-10 times a frequency (f0) found by [f0=(1000.V)/(60.W)] is impressed on the discharge electrode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing static electricity from a web-shaped running body such as a plastic film or paper which is continuously produced and processed, or a charged running body such as copying paper used in an electrostatic copying machine.

[0002]

2. Description of the Related Art Insulators such as plastic films and papers are easily charged during traveling due to friction caused by conveyance by conveyance rolls, etc., and if electrified, wrinkles or discharges occur when wound. There was a safety issue as well as the quality of the. In addition, when a roll-shaped film or paper wound in a charged state is rewound for use or processing, various problems such as discharge during peeling and meandering of the film or paper during the rewinding process may occur. Occurs.

Further, in the electrostatic copying machine, the paper is charged in the copying process, and if the charged paper is not properly discharged, there is a problem in that the paper is attracted to the transport roll or the paper is attracted to each other. It was happening. In order to solve these problems associated with electrification, conventionally, a thin grounded brush-shaped conductor is brought close to the charged body that is the object of static elimination, and a corona discharge is generated at the tip of the brush to eliminate static electricity. Electric appliances and voltage application type static eliminators that apply high-voltage commercial frequency AC voltage or DC voltage to needle-shaped electrodes to generate corona discharge and eliminate static electricity have been used.

Further, in the high-frequency static eliminator disclosed in Japanese Patent Laid-Open No. 63-301495, a needle-shaped electrode and a ground are provided on both sides of the running body to be neutralized in order to neutralize the web-shaped running body that runs at high speed. A roll was provided, and a high-frequency voltage was applied to the needle-shaped electrode to remove static electricity from the running body.

[0005]

By the way, the static elimination principle of the conventional static eliminator utilizing corona discharge is that positive and negative ions are generated by the corona discharge in the electrode regardless of the self-discharge type or the voltage application type. Then, the electric field of the charged body attracts ions having a polarity opposite to the static electricity of the charged body to neutralize the static electricity of the charged body.

However, in the case of uneven charging generated on the charged body, that is, bipolar charging or a minute discharge mark, which is a positive and negative repeated bipolar pattern generated at a fine pitch on the charged body, the electric field of the charged body is very weak. In addition, since the electric field is closed on the surface of the charged body, necessary ions cannot be attracted, and there is a problem that the charge cannot be removed. On the other hand, in the high-frequency static eliminator disclosed in the above-mentioned Japanese Patent Laid-Open No. 63-301495, although a part of the above-mentioned minute charge can be neutralized, an appropriate static elimination condition has not been established because the static elimination mechanism has not been clarified.
For this reason, there are problems that the charge removal of the charged body is unstable and complete charge removal cannot be performed, or conversely new discharge marks are generated.

The object of the present invention is to solve the above problems,
It is an object of the present invention to provide a method of removing charge from a charged running body, which can remove charge even from a finely charged bipolar charge or a minute discharge mark.

[0008]

Means and Actions for Solving the Problems The present inventors have
As a result of repeated intensive studies on the charge removal of the charged body,
The present invention has been completed by elucidating the charge removal mechanism for bipolar charging with a fine pitch and minute discharge marks. That is, according to the present invention, in order to achieve the above object, an AC voltage is applied to a discharge electrode provided in a non-contact state on one side of a web-shaped charging running body, and an earth electrode provided on the opposite side of the charging running body. In the method of destaticizing a charging traveling body for generating a corona discharge between the discharging electrode and the charging traveling body, the discharging electrode and the charging when measured on the shortest path connecting the discharging electrode and the ground electrode. The distance to the running body is d
₁ (mm), the thickness of the air and the dielectric layer interposed between the charging traveling body and the ground electrode are d ₂ and d ₃ (m), respectively.
m), where ε is the relative permittivity of the dielectric layer, the discharge electrode is set to satisfy the following range: 8 ≦ d ₁ + d ₂ + d ₃ / ε ≦ 25 1 ≦ d ₂ + d ₃ / ε ≦ 5 , By adjusting the positional relationship between the charging traveling body and the ground electrode and the thickness and material of the dielectric layer, and applying a traveling speed of the charging traveling body of V (m / min.) And a half cycle of an AC voltage. When the static elimination width for static elimination of a stationary object is W (mm), an AC voltage having a frequency 1 to 10 times the frequency f ₀ obtained by f ₀ = (1000 · V) / (60 · W) is applied to the discharge electrode. It is the method of applying the electric charge to and removing the charge.

Here, when the ground electrode is provided in direct contact with the charging running body, the discharge electrode is not arranged directly above the ground electrode. When the discharge electrode is arranged directly above the ground electrode, the ions generated by the corona discharge collide with the charged running body violently, which is not preferable for static elimination. On the other hand, when the ground electrode is provided in contact with the dielectric layer, or when the ground electrode is provided directly or in the non-contact state with the charging traveling body via the dielectric layer, the discharge electrode is placed directly above the ground electrode. You may.

Further, in the present invention, the discharge electrode is not particularly limited as long as it satisfies the above conditions, for example, needle electrodes or a diameter of 0. A wire electrode having a corona wire of about 1 mm can be used. The method for removing charge from a charged running body according to the present invention includes a voltage application type discharge electrode on one side of the charged running body to be removed and a ground electrode on the opposite side, and positive and negative ions generated by corona discharge are charged and run on the charged running body. It is not an electric field generated by the body, but is forcibly driven into the charging running body by the electric field connecting the discharge electrode and the ground electrode, and is forcibly charged to neutralize bipolar charging or minute discharge traces having a minute pitch. is there.

Therefore, in the method of the present invention, preferably, the discharge electrode has a charged charge density on the surface of the charging traveling body of 2 to 20 μm when an AC voltage half cycle is applied.
C / m ² . More preferably, the earth electrode is on the same side as the discharge electrode with respect to the charging traveling body, in a non-contact state in a range of 5 to 25 mm upstream or / and downstream of the discharge electrode with reference to the traveling direction of the charging traveling body. To eliminate electricity.

Hereinafter, a method of removing the static electricity of the charged running body as the static elimination target by the static elimination method of the present invention will be described. Figure 1
FIG. 3 is a configuration diagram showing a device arrangement in the case of removing charge from the charging traveling body 1 based on the method of the present invention, in which the earth roll 2 is below the charging traveling body 1 traveling at a predetermined traveling speed and the discharging is above. An electrode 3 is arranged, and the discharge electrode 3 is connected to a variable frequency high voltage power source (hereinafter referred to as “high voltage power source”) 4.

Here, the charging traveling body 1 is a web-shaped traveling body made of an insulating material such as a plastic film or paper conveyed by a conveyance roll (not shown). The earth roll 2 is a metal roller that serves as an earth electrode, has a surface covered with a dielectric layer 2 a, and is arranged in contact with the charging traveling body 1. This earth roll 2 has a discharge electrode directly or via a dielectric layer and directly above the discharge electrode when it is placed in a non-contact state with the charging traveling body 1, while it has a discharge electrode when placed in a direct contact state. They are arranged in the vicinity of the downstream side in the traveling direction and arranged respectively.

The discharge electrode 3 is arranged in a non-contact state with the charging traveling body 1, generates corona discharge by an AC voltage applied from the high voltage power source 4, and discharges the ions generated by the corona discharge to the discharge electrode 3 and the ground. The charging traveling body 1 is forcibly driven by the electric field connecting the rolls 2 to be forcibly charged. As a result, the charging traveling body 1 is neutralized by removing bipolar charges and minute discharge marks having a minute pitch.

An example of such a discharge electrode 3 will be described with reference to FIGS. 2 and 3. The discharge electrode 3 has a core wire 30.
A high voltage cable 30 in which a is covered with an insulating material 30b, a plurality of conductive rings 31 having electrode needles 31a protrudingly provided on the outer periphery thereof and fitted on the high voltage cable 30 at regular intervals, and a plurality of conductive rings on the outer periphery of the high voltage cable 30. An insulating coating 32 that covers the property ring 31 and holders 33 and 33 that support the high-voltage cable 30 from the outside of the insulating coating 32 and plate-shaped ground electrodes 34 and 34 that are attached to both lower sides of the holders 33 and 33 are provided.

Here, each conductive ring 31 has an electrode needle 3
The electrode needle 31a is fitted to the high voltage cable 30 so that the electrode 1a projects from the insulating coating 32 and is located between the ground electrodes 34, 34. Also, the illustrated ground electrode 3
Although 4 is plate-shaped, it goes without saying that it may be rod-shaped. The high-voltage power supply 4 applies an AC voltage to the discharge electrode 3 with an oscillator (not shown) whose oscillation frequency can be controlled.

The charging traveling body 1 is guided to travel by the guide roller 5 arranged on the downstream side, and the generation of vibration accompanying the traveling is suppressed. According to the method of the present invention, an alternating voltage is applied from the high voltage power source 4 to the discharge electrode 3, and the ions generated by the corona discharge are forcibly driven into the charging traveling body 1 by the electric field connecting the discharge electrode 3 and the earth roll 2 to force charging. To do. As a result, the electrified traveling body 1 conveyed by the conveyance rolls (not shown) is neutralized by the bipolar charging having a minute pitch and the minute discharge mark, thereby eliminating the charge.

An important factor in the method of the present invention is the apparent distance d _AD between the discharge electrode and the ground electrode and the apparent distance d _AS between the charging traveling body and the ground electrode. Here, in general, considering the case where a ground electrode is provided via a dielectric layer, the distance between the discharge electrode and the charging traveling body when measured on the shortest path connecting the discharge electrode and the ground electrode. Where d ₁ (mm) is the thickness of the air interposed between the charging traveling body and the surface of the dielectric layer, that is, the distance between the charging traveling body and the surface of the dielectric layer is d ₂ (mm), Where d ₃ (mm) is the thickness of the dielectric layer and ε is the relative permittivity of the dielectric layer, the apparent distance d _AD (mm) between the discharge electrode and the ground electrode is d ₁ ,
If it is omitted because it is sufficiently smaller than d ₂ and d ₃ , it is defined by the following equation. If there is no dielectric layer, d ₂
Is the thickness (mm) of the air present between the charging traveling body and the ground electrode.

D _AD = d ₁ + d ₂ + d ₃ / ε This apparent distance d _AD is an important factor that determines the discharge state between the discharge electrode and the ground electrode. If the distance d _AD is large, no discharge occurs. On the other hand, when the distance d _AD is small, spark discharge is generated, and in order to perform stable discharge, the apparent distance d _AD between the discharge electrode and the ground electrode is limited.

The apparent distance d _AD between the discharge electrode and the ground electrode varies depending on the structure of the discharge electrode, but the charged charge density on the surface of the charged running body when the AC voltage half cycle is applied to the discharge electrode is 2 to 20 μC. / M ² , preferably 5 to 15
When μC / m ² , it is 8 ≦ d _AD ≦ 25 (mm), and more preferably 8 ≦ d _AD ≦ 20 (mm). On the other hand, the apparent distance d between the charging traveling body and the ground electrode
_AS is defined by the following equation in the same manner as described above.

D _AS = d ₂ + d ₃ / ε As described above, an AC voltage having a frequency of f ₀ or more is applied to the discharge electrode, and the apparent distance d _AD between the discharge electrode and the ground electrode and the charged traveling body When the apparent distance d _AS from the ground electrode is determined, the ions generated by the corona discharge at the discharge electrode move toward the ground electrode,
The surface of the charging running body is charged to neutralize uneven charging.

At this time, assuming that the equivalent electrostatic capacitance between the charging running body and the ground electrode is C and the surface charge of the charging running body being charged is Q, the surface potential E of the charging running body is expressed by the following equation. To be done. E = Q / C (1) Here, the equivalent capacitance C is almost inversely proportional to the apparent distance d _AS between the charging traveling body and the ground electrode.

Therefore, even if the equivalent capacitance C is small, that is, the apparent distance d _AS is large and the surface charge Q is in a state where the uneven charging on the surface of the charging traveling body is not sufficiently neutralized, the charging traveling body is The surface potential E of the element rises and the electric field directed to the ground electrode is blocked. As a result, the ions generated at the discharge electrode cannot reach the surface of the charging traveling body, and it becomes impossible to completely neutralize the uneven charging on the surface of the charging traveling body and eliminate the charge.

On the other hand, when the equivalent capacitance C is large, that is, when the apparent distance d _AS is small, the surface potential E of the charging traveling body is
Does not rise, and excessive ions are charged on the surface of the charged running body. As a result, when the charging traveling body separates from the static elimination section and moves away from the ground electrode, the charging traveling body becomes in a state of being charged to a high potential, and not only the original purpose of static elimination is not achieved, but also discharge occurs on the surface of the charging traveling body. This will leave discharge marks on the surface.

From the above, the equivalent capacitance C, that is, the apparent distance d _AS is preferably 1 ≦ d _AS ≦ 5 (mm), and more preferably 1 ≦ d _AS ≦ 3 ( m
m). It should be noted that the charging traveling body must be in a non-contact state in which one side is separated from the discharge electrode, but the other side may be in contact with the ground electrode or the dielectric layer or may be in a non-contact state. Here, when the charging traveling body and the ground electrode are arranged in direct contact with each other, the discharge electrode is not arranged directly above the ground electrode.

However, when the charging traveling body is caused to travel without contact with the ground electrode or the dielectric layer, the apparent distance d _AS between the charging traveling body and the ground electrode changes due to the vibration accompanying the traveling. Therefore, as is clear from the equation (1),
As a result of the fluctuation of the surface potential E of the charging traveling body, that is, the equivalent electrostatic capacitance C, the static elimination effect of the charging traveling body changes.
Therefore, in order to suppress the change in the apparent distance d _AS and keep the apparent distance d _AS constant, the charging traveling body is caused to travel via a supporting means such as a roller, and a static eliminator is provided above it.

In this case, the roller surface must be covered with a dielectric material such as rubber or ceramic instead of a conductor such as metal. At this time, the dielectric has an apparent distance d _AS of 1 ≦ d
_It is necessary to determine the material and thickness from the dielectric constant, surface resistance, and structure so that _AS ≤ 5 (mm). Here, it is not known whether the electrified running object to be destaticized is charged positively or negatively, and it is necessary to apply an AC voltage to the discharge electrode in order to destaticize the bipolar charging. In this case, in the method of the present invention, the frequency of the applied AC voltage is the next most important factor.

That is, the traveling speed of the charging traveling body is V (m
/ Min.), And the width of static elimination capable of eliminating static objects by applying an AC voltage is W. At this time, the frequency f calculated by the following equation
_{If the} frequency is not higher than ₀ , the entire surface of the charging traveling body cannot be effectively discharged. f ₀ = (1000 · V) / (60 · W) (2) That is, positive and negative repetitive bipolar patterns generated in the charging traveling body by applying an AC voltage of frequency f ₀ or more to the discharge electrode. It is possible to neutralize the bipolar charging and the discharge traces. The AC voltage may be any frequency as long as the frequency is f ₀ or higher, but the load on the power source increases when the frequency is increased, so it is usually 1 to 10 times f ₀ .

It is more effective to charge the ions from the discharge electrode for a plurality of cycles for bipolar charging having a minute pitch and minute discharge traces, and preferably 2 to 6 times f _0. To adjust the power supply frequency. Here, when a half cycle of the AC voltage is applied to the discharge electrode, the static elimination width W capable of static elimination of a stationary object is such that the electrification traveling body of the static elimination target is made stationary,
After the high-voltage power supply is operated for a half cycle by an oscillator whose oscillation cycle can be controlled, the toner used in the electrostatic copying machine is sprinkled on the surface of the charging traveling body to make it visible, which facilitates measurement. The static elimination width W varies depending on the structure of the discharge electrode used and the installation position, but is usually about 5 to 20 mm.

When the method according to the present invention eliminates static charge unevenness on the charging running body, a small amount of charge may remain on the charging running body. This charging is performed by an AC static eliminator using a normal commercial frequency. Alternatively, since it can be easily removed by a DC static eliminator, a static eliminator or the like is installed on the downstream side of the discharge electrode as necessary. Furthermore, in the method for removing static electricity of the charged running body of the present invention, when the charged running body is charged with ions, the surface potential of the charged running body rises, and as a result, the electric field between the discharge electrode and the ground electrode is disturbed and the corona discharge is stopped. . For this reason, even if it is possible to eliminate the charge unevenness at a fine pitch, the charge running body does not reach zero potential, and it is necessary to add a conventional type charge remover on the downstream side in the running direction of the charge running body.

On the other hand, with reference to the traveling direction of the charging traveling body, at least 5 or 2 upstream or downstream of the discharge electrode.
If you add a ground electrode in a non-contact state within a range of 5 mm,
Corona discharge occurs not only between the discharge electrode and the ground electrode, but also between the discharge electrode and the additional ground electrode. Therefore, as a result of stable corona discharge, the discharge electrode can be operated at a slightly lower voltage than in the case where the ground electrode is not added.

Moreover, even if the charged running body is charged with ions and the surface potential rises and the corona discharge between the discharge electrode and the ground electrode is stopped, the corona discharge between the discharge electrode and the additional ground electrode is generated. Continues. Therefore, the ions generated by the continuous corona discharge are attracted to the surface potential of the charging traveling body to neutralize the surface charge, so that the surface potential of the charging traveling body becomes almost zero, and a new static eliminator is provided on the downstream side. Is not necessary, which is preferable.

The charged charge density D on the surface of the charging traveling body when an AC voltage half cycle is applied to the discharge electrode is
Calculate as follows. First, the charging running body is stopped, and the surface potential E ₁ of the charging running body is measured with a known surface electrometer. Next, a high-voltage power supply is operated for half a period by an oscillator whose oscillation frequency can be controlled, corona discharge is generated at the discharge electrode to charge the charged running body with ions, and then the surface potential E ₂ of the charged running body is measured again. To do. At this time, if the air and the thickness d ₂ and d ₃ (mm) of the dielectric layer and the dielectric constant ε of the dielectric layer interposed between the charging traveling body and the ground electrode are also measured, the charge The charge density D is given by the following equation.

D = | E ₁ −E ₂ | / (d ₂ + d ₃ / ε)

[0035]

【Example】

Example 1 In FIG. 1, the charging traveling body 1 has a thickness of 7 μm and a width of 200
A metal roll having a diameter of 200 mm, the surface of which is a chrome-plated polyester film (Lumirror manufactured by Toray Industries, Inc., product number: 7YN394), the surface of which is plated with chrome, and the discharge electrodes 3 are ground electrodes 34, 34. Using the discharge electrodes 3 shown in FIG. 2 and FIG. 3 without the above, the charging running body 1 was run at a speed of 90 m / min.

Prior to the charge removal treatment, the toner of an electrostatic copying machine was sprinkled on the polyester film to visualize the charged state. As a result, minute bipolar charge irregularities of about 2 mm pitch generated in the manufacturing process were observed on the film. Was seen. At this time, the discharge electrode 3 is arranged at a position slightly offset to the downstream side from the earth roll 2 as shown in FIG. 1, and the distance d ₁ between the discharge electrode 3 and the charging traveling body 1 is 11 m.
m, the charging electrode 1 and the earth roll 2 on the shortest path connecting the discharge electrode 3 and the earth roll 2 caused by disposing the discharge electrode 3 at a position slightly deviated from just above the earth roll 2 to the downstream side. The gap distance d ₂ between and was set to 1 mm.

In this state, the charging traveling body 1 was stopped, the AC voltage of 180 Hz was applied to the discharge electrode 3 from the high voltage power source 4 for a half cycle, and the static elimination width W was measured to be 17 mm. Therefore, the frequency to be applied to the discharge electrode (2)
From the formula, f ₀ = (1000 · V) / (60 · W) = (1000 · 90) / (60 · 17) = 88.2 (Hz).

Therefore, 180 H which is about twice the frequency f ₀
The high-voltage power supply 4 is set with z as the power supply frequency, a 10-KV 0-Peak AC voltage is applied from the high-voltage power supply 4 to the discharge electrode 3, and the charging traveling body 1 is run at a speed of 90 m / min. Then, the static elimination effect was judged by sprinkling the toner of the electrostatic copying machine on the charged running body 1 after the static elimination to make it visible.

As a result, minute bipolar charging unevenness of about 2 mm pitch and other discharge marks which were originally present on the polyester film were not seen, and pale positive and negative charging patterns of 8 mm pitch were observed. This pale positive and negative electrification pattern is due to the fact that the AC voltage applied to the discharge electrode 3 was 180 Hz and the polyester film to be neutralized was run at a speed of 90 m / min. It is the one with the charging marks left.

The pale positive and negative electrification patterns do not deteriorate the quality of the polyester film as a product because the electrification level is low. Example 2 Ground electrodes 34, 34 were attached to the discharge electrode 3 of Example 1, and this discharge electrode 3 was arranged at the same position as in Example 1,
The polyester film is run at a speed of 90 m / min.
A 9 KV 0-Peak AC voltage is applied to remove electricity,
The static elimination effect was determined in the same manner as described above.

As a result, the minute bipolar electrification irregularities of about 2 mm pitch originally present on the polyester film were not observed, and the pale positive and negative electrification patterns generated in Example 1 were not observed. Was determined to be almost completely discharged. Example 3 Instead of the metal roll having a diameter of 200 mm used in Example 1,
N with a thickness of 15 mm and a relative permittivity ε of about 5 on a core metal with a diameter of 70 mm
The earth roll 2 coated with BR (acrylonitrile-butadiene rubber) is arranged in contact with the charging traveling body 1, and the discharge electrode 3 having the ground electrodes 34, 34 is mounted directly above the earth roll 2 and the ground electrode 2. The distance from the roll 2, that is, the distance d ₁ between the discharge electrode 3 and the charging traveling body ₁ was set to 11 mm.

At this time, the apparent distance d _AD between the discharge electrode 3 and the earth roll 2 and the apparent distance d _AS between the charging traveling body 1 and the earth roll 2 are d _AD = 14 m, respectively.
m, d _AS = 3 (= _15/5 ) mm. Under such conditions, the polyester film of Example 1 was treated at 60 m / mi.
While running at a speed of n., a high-voltage power supply 4 applied a 0-Peak AC voltage of 120 Hz and 9 KV to the discharge electrode 3 to perform static elimination, and the static elimination effect was determined in the same manner as described above.

As a result, the polyester film was almost completely discharged as in the case of Example 2. For comparison, in FIG. 1, the discharge electrode 3 to which the ground electrodes 34, 34 are attached is separated by 120 mm on the downstream side and is separated by 20 mm from the charging traveling body 1 made of the same polyester film as in the above embodiment. While moving to the position shown and running the charging traveling body 1 at a speed of 90 m / min., A 0-Peak AC voltage of 60 Hz and 9 KV was applied to the discharge electrode 3 from the high voltage power source 4, but the charging traveling body 1 was neutralized. I couldn't.

[0044]

As is apparent from the above description, according to the method of removing static electricity of a charged running body of the present invention, charge removal of the charged running body, in particular, ambipolar charging and minute charging which are positively and negatively charged at a fine pitch. It has an excellent effect that the discharge mark can be discharged at a practical level. Also, if a second earth electrode is provided in a non-contact state at least in the range of 5 to 25 mm upstream or downstream of the discharge electrode, even if the corona discharge between the discharge electrode and the earth electrode is stopped, it will be expanded with the discharge electrode. Since the corona discharge between the second ground electrode and the second ground electrode is continued, the surface of the charged running body that is the target of static elimination can be easily controlled to almost zero potential without providing a new static eliminator on the downstream side.

[Brief description of drawings]

FIG. 1 is a configuration diagram illustrating an apparatus arrangement for explaining a method of removing static electricity from a charged traveling body according to the present invention.

FIG. 2 is a front view showing an example of a discharge electrode used in the charge eliminating method of the present invention in a partial cross section.

FIG. 3 is a side view of the discharge electrode shown in FIG.

[Explanation of symbols]

1 Charging Running Body 2 Earth Roll (Earth Electrode) 2a Dielectric Layer 3 Discharge Electrode 4 Frequency Variable High Voltage Power Supply 5 Guide Roller 30 High Voltage Cable 30a Core Wire 30b Insulation Material 31 Conductive Ring 31a Electrode Needle 32 Insulation Coating 33 Holder 34 Ground Electrode d ₁ Distance between discharge electrode and charge running body d ₂ Air thickness (intervened between charge running body and ground electrode)

Claims (4)

[Claims] 1. An AC voltage is applied to a discharge electrode provided on one side of a web-shaped charging traveling body in a non-contact state to generate corona discharge between the discharge electrode and a ground electrode provided on the opposite side of the charging traveling body. In the method for removing charge from the charging running body, the distance between the discharge electrode and the charging running body is d when measured on the shortest path connecting the discharge electrode and the ground electrode. ₁ (mm), the thickness of the air and the dielectric layer interposed between the charging traveling body and the ground electrode is d ₂ ,
d ₃ (mm), where ε is the relative permittivity of the dielectric layer, the range is 8 ≦ d ₁ + d ₂ + d ₃ / ε ≦ 25 1 ≦ d ₂ + d ₃ / ε ≦ 5. The positional relationship among the discharge electrode, the charging traveling body, and the ground electrode and the thickness and material of the dielectric layer are adjusted, and the traveling speed of the charging traveling body is V (m / min.), AC voltage half cycle. The static elimination width that can eliminate static electricity by applying
(Mm), it is characterized in that an AC voltage having a frequency of 1 to 10 times the frequency f ₀ calculated by f ₀ = (1000 · V) / (60 · W) is applied to the discharge electrode to remove electricity. A method for removing static electricity from a charged running body. 2. The method according to claim 1, wherein the discharge electrode has a charge density of ² to 20 μC / m ^{2 on} the surface of the charging traveling body when an AC voltage half cycle is applied. 3. A non-contact state on the same side as the discharge electrode with respect to the charging traveling body, in the range of 5 to 25 mm upstream or / and downstream of the discharging electrode with reference to the traveling direction of the charging traveling body. 2. A grounding electrode is provided to eliminate static electricity.
Alternatively, the method for removing static electricity from the charged running body according to item 2. 4. The method for static elimination of a charged running body according to claim 1, wherein the ground electrode is a grounded metal roll or a grounded metal roll whose surface is covered with a dielectric layer.