JP2009059590A - Static eliminator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a static eliminator capable of suppressing fluctuations in ionic balance while enabling a long-term use. <P>SOLUTION: The static eliminator 10 is equipped with a plurality of discharge electrodes 13, a positive polarity voltage circuit 22, a negative polarity voltage circuit 24, and a control means 44 in which a positive polarity voltage from the positive voltage circuit 22 and a negative polarity voltage from the negative polarity voltage circuit 24 are applied to the respective discharge electrodes 13 at different periods of time. In the control means 44, at the same period of time, the positive polarity voltage is applied to a part of the discharge electrodes 13 among the plurality of the discharge electrodes 13, and the negative polarity voltage is applied to another part of the discharge electrodes 13. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a static eliminator.

  The static eliminator is intended to neutralize the charge removal object by spraying positive and negative ions onto the charge removal object, in other words, neutralize the charge of the charge removal object. There is.

  The direct current type includes a positive discharge electrode that always generates positive ions when a positive voltage is applied, and a negative discharge electrode that generates only negative ions when a negative voltage is always applied. Yes. For this reason, in the DC type, since positive ions and negative ions can be sprayed on the static elimination object at the same time, there is an advantage that the static elimination speed (the time required to neutralize a charged body of a predetermined potential) is fast. On the other hand, the DC type has a demerit that the positive / negative ion balance is lost by long-term use. That is, the discharge electrode varies in the degree of wear over time depending on the polarity of the applied voltage. In the direct current type, as described above, the voltage of the same polarity is always applied to each discharge electrode, so that a difference occurs in the degree of wear between the positive discharge electrode and the negative discharge electrode due to long-term use. The positive and negative ion balance is lost, and the static elimination performance is lowered.

On the other hand, the AC type is a configuration in which positive and negative voltages are alternately applied to the same discharge electrode, and positive and negative ions are alternately generated from the same discharge electrode (Patent Document). 1 and 2). Here, some AC-type static eliminators include a plurality of the discharge electrodes in order to eliminate static charges over a wide range. However, as described above, the AC type has a configuration in which a positive voltage and a negative voltage are alternately applied to the same discharge electrode, so that the ion balance is less likely to be lost after a long period of use compared to the DC type. There is.
JP 2000-58290 A JP 2004-63431 A

  However, the conventional AC-type static eliminator including a plurality of discharge electrodes is configured to apply a voltage of the same polarity to all the discharge electrodes at the same time. For this reason, only one of positive ions and negative ions is sprayed on the static elimination object at the same time, and the ion balance changes greatly with time. There was a problem that the static elimination performance was inferior to that.

  The present invention has been completed based on the above circumstances, and an object of the present invention is to provide a static eliminator capable of suppressing fluctuations in ion balance while enabling long-term use.

As a means for achieving the above object, a static eliminator according to a first invention includes a plurality of discharge electrodes, a positive voltage circuit that outputs a positive voltage, and a negative voltage circuit that outputs a negative voltage. A control means for applying the positive voltage from the positive voltage circuit and the negative voltage from the negative voltage circuit at different times to each of the discharge electrodes, At the same time, the positive voltage from the positive voltage circuit is applied to a part of the plurality of discharge electrodes, and the negative voltage from the negative voltage circuit is applied to another part of the discharge electrodes. Is applied.
According to the present invention, since the positive voltage and the negative voltage are applied to each discharge electrode at different times, it is possible to suppress a reduction in static elimination performance due to long-term use compared to a DC type static elimination apparatus. . In addition, in the same period, the positive voltage is applied to some discharge electrodes, and the negative voltage is applied to some other discharge electrodes. Can be suppressed.

The second invention is the static eliminator according to the first invention, wherein the control means has the same number of discharge electrodes to which the positive voltage is applied as the number of discharge electrodes to which the negative voltage is applied. Control to become.
According to the present invention, it is possible to suppress ion balance fluctuations to a direct current type.

A third invention is the static eliminator of the first or second invention, wherein the plurality of discharge electrodes are divided into a plurality of unit discharge electrodes by a predetermined number, and the plurality of unit discharge electrodes are arranged in a line. And the control means alternately applies the positive voltage and the negative voltage to each of the unit discharge electrodes, and the applied voltages of the adjacent unit discharge electrodes are opposite in polarity at the same time. Control to become.
According to the present invention, a positive voltage and a negative voltage are alternately applied to each unit discharge electrode (a predetermined number of discharge electrodes), and a reverse polarity voltage is applied to adjacent unit discharge electrodes at the same time. Therefore, fluctuations in ion balance can be more reliably suppressed.

A fourth invention is the static eliminator of the first or second invention, wherein the plurality of discharge electrodes are divided into a plurality of unit discharge electrodes by a predetermined number, and the plurality of unit discharge electrodes are zigzag-shaped. And the control means alternately applies the positive voltage and the negative voltage to each of the unit discharge electrodes, and the applied voltages of the adjacent unit discharge electrodes are opposite in polarity at the same time. Control to become.
When the applied voltages between adjacent unit discharge electrodes are reversed in polarity at the same time, it is necessary to keep the distance between the unit discharge electrodes as far as possible so as not to affect each other. Therefore, by arranging a plurality of unit discharge electrodes in a zigzag shape, the total length of the static eliminator can be shortened compared to a case where the unit discharge electrodes are arranged in a line, and a plurality of units in the arrangement direction of the plurality of unit discharge electrodes. Discharge electricity can be arranged in close proximity, and high-density positive and negative ions can be generated.

A fifth invention is the static eliminator of any one of the first to fourth inventions, wherein the another partial discharge electrode excludes the partial discharge electrode among all the discharge electrodes. All of the remaining discharge electrodes.
According to the present invention, positive ions or negative ions are generated from all the discharge electrodes, so that the charge can be removed efficiently.

  According to the present invention, fluctuations in ion balance can be suppressed while enabling long-term use.

<Embodiment 1>
Embodiment 1 of the present invention will be described with reference to FIGS.
(Overall configuration of static eliminator)
As shown in FIG. 1, a static eliminator 10 according to the present embodiment includes a plurality of discharge electrodes 13 (discharge needles) arranged in a line, and a static elimination object W (for example, a wide range of substrates or liquid crystals) that requires a wide range of static elimination. It is used to remove static electricity from a wide range of workpieces such as films and packaging films.

  Specifically, the static eliminator 10 has a plurality of outlets 12 formed in a line on one side of the box-shaped case 11. A discharge electrode (discharge needle) 13 is provided in each outlet 12. A cross flow fan (not shown) is disposed behind each discharge electrode 13, and positive ions and negative ions generated in each discharge electrode 13 are respectively flown by the air flow sent by the cross flow fan. It can be sent out from the outlet 12 to the outside.

(Electrical configuration)
FIG. 2 shows the electrical configuration of the static eliminator 10 (excluding the configuration for the cross flow fan).

  A voltage doubler rectifier circuit (an example of a positive voltage circuit) 22 that outputs a DC high voltage (positive polarity) is connected to the AC power source 20 via a transformer 21. The secondary terminal of the transformer 21 is connected to the input terminal 25 of the voltage doubler rectifier circuit 22, and when the power supply voltage of the AC power supply 20 is applied to the transformer 21, the voltage is multiplied by the turn ratio. The voltage is boosted and the secondary voltage V1 is applied to the input terminal 25A.

  In addition, a voltage doubler rectifier circuit (an example of a negative voltage circuit) 24 that outputs a DC high voltage (negative polarity) is connected to the AC power source 20 via a transformer 23. The secondary terminal of the transformer 23 is connected to the input terminal 26 of the voltage doubler rectifier circuit 24. When the power supply voltage of the AC power supply 20 is applied to the transformer 23, the voltage is multiplied by the turn ratio. The voltage is boosted and the secondary voltage V1 is applied to the input terminal 26A.

  Both voltage doubler rectifier circuits 22 and 24 are so-called Cockcroft-Walton type voltage doubler rectifier circuits. The voltage doubler rectifier circuit 22 is composed of capacitors 27 and 28 and rectifying diodes 29 and 30, and when the secondary voltage V1 of the transformer 21 is applied to the input terminals 25A and 25B, the secondary voltage V1. Of the output side terminal 31 appears at the terminal 31A on one side of the output side terminal 31 with the polarity shown in the figure.

  More specifically, when an AC voltage (secondary voltage V1) that causes the input terminal 25B of the voltage doubler rectifier circuit 22 to be positive is applied, the rectifier diode 29 is energized, so that the capacitor 27 becomes 2 The battery is charged to the voltage level of the next voltage V1.

  After that, the polarity of the secondary voltage V1 is switched, and this time, when a voltage that makes the input terminal 25A positive is applied, the secondary side of the transformer 21 and the capacitor 27 are in series, Since the diode 30 is energized, the capacitor 28 is charged and eventually reaches a voltage level twice that of the secondary voltage V1. As a result, a voltage twice the secondary voltage V1 appears at the terminal 31A on one side of the output side terminal 31 with the polarity shown in the figure. The other output terminal 31B of the voltage doubler rectifier circuit 22 is connected to the ground.

  On the other hand, the basic configuration of the voltage doubler rectifier circuit 24 is the same as that of the voltage doubler rectifier circuit 22, and includes a capacitor 35, 36 and rectifier diodes 37, 38. A voltage twice as large as V1 appears at the terminal 39A on one side of the output side terminal 39 with the polarity shown. The other output terminal 39B of the voltage doubler rectifier circuit 24 is connected to the ground.

  Here, the plurality of discharge electrodes 13 are divided into two groups (first group G1 and second group G2) of the same number, and the discharge electrodes 13 of the first group G1 (an example of some discharge electrodes) Hereinafter, the first discharge electrodes 13A) and the second group of discharge electrodes 13 (an example of another part of the discharge electrodes, hereinafter referred to as the second discharge electrodes 13B) are alternately arranged (FIG. 1, FIG. 2). In FIG. 2, only four of the plurality of discharge electrodes 13 are shown, and the other discharge electrodes 13 are omitted.

  Two sets of semiconductor switches are connected in parallel between the output terminal 31A of the voltage doubler rectifier circuit 22 and the output terminal 39A of the voltage doubler rectifier circuit 24. The first set of semiconductor switches 40, 41 are connected in series between the output terminal 31 A of the voltage doubler rectifier circuit 22 and the output terminal 39 A of the voltage doubler rectifier circuit 24, and the first switch is between the semiconductor switches 40, 41. A group of discharge electrodes 13A is connected. On the other hand, the second set of semiconductor switches 42, 43 are connected in series between the output terminal 31 A of the voltage doubler rectifier circuit 22 and the output terminal 39 A of the voltage doubler rectifier circuit 24, and the above-described semiconductor switches 42, 43 are connected with each other. The second discharge electrode 13B group is connected. Further, the static eliminator 10 is provided with a switch drive unit 44 that drives the semiconductor switches 40 to 43 on and off. The semiconductor switches 40 to 43, the switch driving unit 44, and the inverting circuit 45 are an example of control means.

  The semiconductor switches 40 to 43 are all formed of a power MOSFET (hereinafter simply referred to as an FET), but a silicon carbide semiconductor (SiC) is used as a semiconductor constituting the FET. A semiconductor containing silicon carbide as a semiconductor component has a wide band gap as a physical property. Therefore, when a switching element such as an FET is formed of such a semiconductor, there is a characteristic that electric charge hardly moves on the PN junction surface and the withstand voltage is high. If a switching element having such characteristics is used as a switch on the high voltage side, switching of high voltage can be performed with a small number of switching elements, so that the number of components can be reduced and the circuit can be miniaturized.

(Operation of the static eliminator)
The switch drive unit 44 outputs a pulse signal S1 when the static eliminator 10 is powered on. The semiconductor switches 40 and 43 receive the pulse signal S1 as it is, while the semiconductor switches 41 and 42 receive a signal obtained by inverting the high / low level of the pulse signal S1 by the inverting circuit 45.

  Thereby, as shown in FIG. 3, when the pulse signal S1 is at a high level, the semiconductor switches 40 and 43 are turned on while the semiconductor switches 41 and 42 are turned off. That is, the first discharge electrode 13A is applied with a positive high voltage from the voltage doubler rectifier circuit 22 and generates positive ions by corona discharge (refer to the period indicated by “+” in FIG. 3). At this time, a negative high voltage is applied from the voltage doubler rectifier circuit 24 to the second discharge electrode 13B, and negative ions are generated by corona discharge (refer to a period indicated by “−” in FIG. 3).

  Next, when the pulse signal S1 changes from the high level to the low level, the semiconductor switches 41 and 42 are turned on while the semiconductor switches 40 and 43 are turned off. That is, the first discharge electrode 13A is applied with a negative high voltage from the voltage doubler rectifier circuit 24, and generates negative ions by corona discharge (see the period indicated by “-” in FIG. 3). At this time, a positive high voltage is applied from the voltage doubler rectifier circuit 22 to the second discharge electrode 13B, and positive ions are generated by corona discharge (refer to the period indicated by “+” in FIG. 3).

  As described above, each discharge electrode 13 alternately generates positive ions and negative ions by applying a positive high voltage and a negative high voltage alternately. Adjacent ones (the first discharge electrode 13A and the second discharge electrode 13B) are applied with high voltages having opposite polarities at the same time to generate ions having opposite polarities.

(Effect of this embodiment)
According to this embodiment, since it is a pulse AC type configuration in which a positive voltage and a negative voltage are applied to each discharge electrode 13 at different times, the discharge electrode 13 is used for a long period of time compared to a DC type static eliminator. A reduction in static elimination performance can be suppressed. In the same period, a positive voltage is applied to a part of the discharge electrodes 13 (for example, the first discharge electrode 13A), and a negative voltage is applied to another part of the discharge electrodes 13 (for example, the second discharge electrode 13B). Since it is the structure to apply, the fluctuation | variation of ion balance can be suppressed compared with the conventional alternating current type.

  Here, in the conventional AC type, if the polarity of the voltage applied to the discharge electrode is reversed at a high speed by a pulse signal of a high frequency (for example, several tens [KHz]), the generation timing of the positive ions and the negative ions The generation time is alternately switched in a short time, and the fluctuation of the ion balance can be suppressed. However, there is a demerit that the higher the frequency, the slower the static elimination speed. On the other hand, if the conventional AC type has a low frequency (for example, several tens [Hz]), the static elimination speed can be increased compared to the high frequency. However, in the conventional AC type, the same polarity voltage is applied to all discharge electrodes at the same time, so at low frequency, only one polarity ion is generated for a long time, and the ion balance fluctuation ( There is a demerit that the fluctuation voltage) is large. On the other hand, in the present embodiment, as described above, since the positive voltage and the negative voltage are applied to the discharge electrodes 13 at different times, the pulse AC type configuration is used. It is possible to suppress ion balance fluctuations while increasing the static elimination speed as a low frequency signal.

  The plurality of discharge electrodes 13 are divided into two groups (the first group G1 and the second group G2) of the same number, and the discharge electrodes 13 to which a positive high voltage is applied and the negative electrode high The number of discharge electrodes 13 to which a voltage is applied is approximately the same at the same time. Therefore, since positive ions and negative ions can be generated in substantially the same amount during the static elimination operation, ion balance fluctuations can be suppressed to about the DC type. It should be noted that the same number in the present embodiment does not necessarily mean only the same number, and may be approximately the same number within a range that does not substantially affect the static elimination effect. There may be differences.

Further, according to the present embodiment, adjacent ones (the first discharge electrode 13A and the second discharge electrode 13B) are applied with high voltages having opposite polarities at the same time to generate ions having opposite polarities. Therefore, the static elimination object W can be uniformly eliminated.
Moreover, in this embodiment, since it is the structure which always produces | generates positive polarity ion or negative polarity ion from all the discharge electrodes 13, it can discharge efficiently.

<Embodiment 2>
FIG. 4 shows a second embodiment. The difference from the above embodiment lies in the configuration and operation of the control means, and the other points are the same as in the first embodiment. Therefore, the same reference numerals as those in the first embodiment are given and the redundant description is omitted, and only different points will be described next. In FIG. 4, only four of the plurality of discharge electrodes 13 are shown, and the other discharge electrodes 13 are omitted.

  As shown in FIG. 4, the static eliminator 10 of the present embodiment is provided with a plurality of semiconductor switches 51 to 54 corresponding to the respective discharge electrodes 13. The switch driving unit 55 can turn on / off each of the semiconductor switches 51 to 54 independently, whereby the polarity of the voltage applied to each discharge electrode 13 can be switched independently. In the first embodiment, the polarity inversion of the voltage applied to the first discharge electrode 13A and the polarity inversion of the voltage applied to the second discharge electrode 13B are set to have opposite phases (shifted by 180 degrees). It was. On the other hand, in this embodiment, the polarity inversion of the voltage applied to each discharge electrode 13 is shifted along the arrangement order by a predetermined phase (for example, 90 degrees). Thereby, the position of the discharge electrode for generating positive ions and the position of the discharge electrode for generating negative ions can be varied for each polarity inversion, and the static elimination object W can be uniformly discharged.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) As the “unit discharge electrode”, one discharge electrode 13 is used in each of the first and second embodiments. However, the present invention is not limited thereto, and two or more discharge electrode groups may be used.

  (2) In the first embodiment, a positive voltage and a negative voltage are alternately applied to each discharge electrode 13, but it is not always necessary to be alternately. In short, a positive voltage and a negative voltage May be applied at different times (see, for example, Embodiment 2).

  (3) In the above embodiment, either one of the positive voltage and the negative voltage is always applied to all the discharge electrodes 13, but the present invention is not limited thereto, and the positive voltage and the negative voltage are not limited thereto. There may be a discharge electrode to which none of these is applied.

  (4) Although the above embodiment has a configuration in which a plurality of discharge electrodes are arranged in a line, the present invention is not limited to this, and a configuration in which a plurality of discharge electrodes are two-dimensionally arranged may be used. For example, as shown in the upper part of FIG. 5, in the above embodiment, the discharge electrodes 13 are arranged in a line, and ions having opposite polarities are generated from adjacent discharge electrodes 13 at the same time. Therefore, it is necessary to keep the distance between the discharge electrodes 13 as far as possible so as not to affect each other, such as neutralization. Therefore, as shown in the lower part of FIG. 5, the first discharge electrode 13A of the first group G1 and the second discharge electrode 13B of the second group G2 may be arranged in a zigzag (alternate position). With such a configuration, it is possible to shorten the total length (the length in the left-right direction in FIG. 5) of the static elimination device 10 while securing the same distance D as in the first embodiment, and the plurality of discharge electrodes 13. In this arrangement direction (left and right direction in FIG. 5), the discharge electrodes 13 can be arranged close to each other, and high-density positive and negative ions can be generated.

The perspective view of the static elimination apparatus which concerns on Embodiment 1 of this invention. Electrical configuration diagram of static eliminator Time chart showing the polarity of ions generated at the discharge electrode Simplified electrical configuration of Embodiment 2 The schematic diagram which showed arrangement | positioning of the discharge electrode of Embodiment 1 and a modification

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Static elimination apparatus 22 ... Voltage doubler rectifier circuit (positive voltage circuit)
24 ... Voltage doubler rectifier circuit (negative voltage circuit)
40-43 ... Semiconductor switch (control means)
44 ... Switch drive unit (control means)
45. Inversion circuit (control means)
W… Static removal object

Claims (5)

A plurality of discharge electrodes;
A positive voltage circuit that outputs a positive voltage;
A negative voltage circuit for outputting a negative voltage;
Control means for applying the positive voltage from the positive voltage circuit and the negative voltage from the negative voltage circuit to each of the discharge electrodes at different times;
The control means applies the positive voltage from the positive voltage circuit to a part of the plurality of discharge electrodes at the same time, and applies the positive voltage from the negative voltage circuit to another part of the discharge electrodes. The static elimination apparatus which is the structure to which the said negative polarity voltage is applied. It is a static elimination apparatus of Claim 1, Comprising:
The control means controls so that the number of discharge electrodes to which the positive voltage is applied and the number of discharge electrodes to which the negative voltage is applied are the same in the same period. It is a static elimination apparatus of Claim 1 or Claim 2, Comprising:
The plurality of discharge electrodes are divided into a predetermined number to be a plurality of unit discharge electrodes, and the plurality of unit discharge electrodes are arranged in a line,
The control means controls the positive voltage and the negative voltage to be alternately applied to each of the unit discharge electrodes, and the applied voltages of the adjacent unit discharge electrodes have opposite polarities at the same time. To do. It is a static elimination apparatus of Claim 1 or Claim 2, Comprising:
The plurality of discharge electrodes are divided into a predetermined number to be a plurality of unit discharge electrodes, and the plurality of unit discharge electrodes are arranged in a zigzag shape,
The control means controls the positive voltage and the negative voltage to be alternately applied to each of the unit discharge electrodes, and the applied voltages of the adjacent unit discharge electrodes have opposite polarities at the same time. To do. It is a static elimination apparatus as described in any one of Claims 1-4,
The another partial discharge electrode is all the remaining discharge electrodes excluding the partial discharge electrode among all the discharge electrodes.

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