Ion generator

Provided is an ion generator that sends out air ions generated by applying high voltage between a discharge electrode and a counter electrode, the ion generator including: an air discharge port provided in a housing of the ion generator to send ejected air toward a region between the discharge electrode and the counter electrode; and an opening portion configured to discharge the generated air ions by the ejected air, in which the counter electrode is positioned on an upstream side of the flow of the ejected air with respect to the discharge electrode.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is entitled to the benefit of and incorporates by reference subject matter disclosed in International Patent Application No. PCT/JP2014/079858 filed on Nov. 11, 2014 and Japanese Patent Application No. 2013-240173 filed on Nov. 20, 2013, the contents of which are hereby incorporated by reference into this application.

TECHNICAL FIELD

The present invention relates to an ion generator that blows positive air ions and negative air ions generated by corona discharge to a charged object (hereinafter, referred to as “target”), thereby neutralizing the charge of the target.

BACKGROUND ART

In order to discharge the target by blowing the air ions to the target charged with static electricity, an ion generator also referred to as an ionizer or a static eliminator is used. The ion generator used in a production line configured to perform manufacturing and assembly of electronic components is used to remove the static electricity charged to a target such as an electronic component and a manufacturing assembly jig. By removing the charged static electricity, foreign matters are prevented from adhering to the electronic component, the jig or the like due to the static electricity, or the electronic component is prevented from being destroyed by the static electricity.

As such an ion generator, there is an ion generator formed with an oblong blow-off opening with an object of discharging the wide target. For example, there is an ion generator that blows out air ions from a blow-off opening (for example, see Japan Unexamined Patent Application Publication No. H06-208898 and Japan Unexamined Patent Application Publication No. H06-275366). In Japan Unexamined Patent Application Publication No. H06-208898 and Japan Unexamined Patent Application Publication No. H06-275366, a plurality of discharge electrodes (discharge needles) is disposed along a longitudinal direction of the oblong blow-off opening at intervals. The air ions are generated between a counter electrode disposed on an outer periphery of the discharge electrode and the discharge electrode. And, compressed air is sent to the entire oblong blow-off opening from a compressor, and is ejected toward a protruding direction of the discharge electrode.

SUMMARY OF THE INVENTION

As a potential difference between the discharge electrode and the counter electrode is large, the corona discharge occurs easily. And, as a distance between the discharge electrode and the counter electrode is short, the corona discharge is liable to occur. For that reason, in the ion generator of the related art, the counter electrode is disposed on the outer periphery near a tip of the discharge electrode or a part of the outer periphery.

There is a technique of grounding the counter electrode via high resistance so that the air ions generated by the discharge electrode are not captured by the counter electrode. In this configuration, when voltage is applied to the discharge electrode, the air ions are generated by the discharge. At the same time, the capture of the air ions to the counter electrode starts. Electric current is generated by flowing of the adsorbed air ions to the counter electrode. For that reason, the potential of the counter electrode rises. As a result, the electric field intensity between the discharge electrode and the counter electrode decreases. Moreover, the air ions generated by the discharge are separated from the discharge electrode, and are easily conveyed to the target.

However, in this configuration, since the electric field intensity between the discharge electrode and the counter electrode decreases along with the adsorption of the air ions to the counter electrode, a generation amount of air ions decreases. In some cases, a balance between negative air ions and positive air ions to be generated, that is, an ion balance is degraded, which makes it difficult to sufficiently discharge the target. When the generation amount of air ions is changed, for example, in some cases, one of the positive charge or the negative charge remains even after neutralization.

The present invention is made in view of the above-described circumstances, and an object thereof is to provide an ion generator that is able to increase a conveyance amount of ion without affecting the generation amount of air ions.

In order to solve the above-described problems, according to the present invention, there is provided an ion generator that sends out air ions generated by applying high voltage between a discharge electrode and a counter electrode, the ion generator including: an air discharge port provided in a housing of the ion generator to send ejected air toward the discharge electrode, and an opening portion provided on a surface of the housing to discharge the generated air ions by the ejected air, in which the counter electrode is positioned on an upstream side of the flow of the ejected air with respect to a discharge tip of the discharge electrode.

It is preferred that the counter electrode be covered with an insulating material. Otherwise, it is preferred that the counter electrode be covered with an insulating film.

It is preferred that the discharge electrode and the counter electrode be incorporated into a discharge electrode unit, and the discharge electrode unit be freely attachable to and detachable from the housing.

It is preferred that the counter electrode be in a strip shape.

It is preferred that an air supply portion be provided in a rear side of the housing to take in outside air into a region where the air ions are generated between the discharge electrode and the counter electrode.

It is preferred that the housing be provided with a cover configured to regulate the flow of outside air incorporated between the discharge electrode and the counter electrode.

It is preferred to provide an air guide member that covers an upper front side of the air discharge port so as to send the ejected air into the opening portion.

In the ion generator according to the present invention, since the counter electrode is located on the rear side by a predetermined distance from the discharge tip of the discharge electrode, an amount of the generated air ions being adsorbed to the counter electrode decreases, therefore the discharge becomes stable and a conveyance amount of air ions also increases. In addition, the balance between positive air ions and negative air ions to be generated is satisfactory. Therefore, neutralization efficiency is improved.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Hereinafter, one embodiment of an ion generator according to the present invention will be described in detail with reference to the drawings. In addition, a vertical direction, a lateral direction (width direction), and a depth direction used in the following description refer to directions as viewed from the front side, when a front side ofFIG. 1is assumed to be a front (surface side). In the embodiment described below, as an example of the ion generator, a wide type product that blows out the generated air ions from an oblong blow-off opening will be described. However, the present invention is not limited thereto.

In the description of the present specification, there is air of three different types. In other words, one is “ejected air”. Another is “outside air”. The other is “assist air”. The “ejected air” is air that is supplied to an air supply port13A (seeFIG. 8) of an ion generator1from a compressor and is discharged from a first air discharge port16(seeFIG. 10). The “outside air” is air that is taken from the periphery of the ion generator1. The “assist air” is air that is discharged from a second air discharge port31(seeFIG. 16). And, the “ion-conveying air” is air that is blown out from a blow-off opening11(seeFIG. 1). The ion-conveying air is air obtained by mixing the ejected air and the outside air.

For example, as illustrated inFIG. 1, the ion generator1is formed by a housing10and a discharge electrode unit20. The discharge electrode unit20is detachably mounted to the housing10from the blow-off opening11.

The housing10is formed in a substantially rectangular shape that is long in the lateral direction. As illustrated inFIGS. 1 and 3, the blow-off opening11is formed on the upper portion of the front surface of the front side of the housing10. The blow-off opening11laterally extends in the longitudinal direction of the housing10.

As illustrated inFIG. 9, a discharge-electrode-unit mounting-portion12is formed in the blow-off opening11. The discharge electrode unit mounting portion12has a recessed square shape in the depth direction, and has the same length as that of the blow-off opening11. The whole discharge electrode unit20illustrated inFIG. 11is fitted into the discharge electrode unit mounting portion12formed in a recessed square shape. In addition, as will be described below, the discharge electrode unit20has a substantially rectangular shape.

Referring again toFIG. 9, a first air supply passage13is provided behind the discharge electrode unit mounting portion12. The first air supply passage13is formed over the entire length in the lateral direction of the blow-off opening11.

As illustrated inFIGS. 1 and 2, the compressed air passes through a tube13B and is supplied to the first air supply passage13from the air supply port13A.

As illustrated inFIG. 9, a first air discharge port16is provided on the upper front side of the first air supply passage13. The first air discharge port16discharges the air toward the rear part of the discharge electrode unit mounting portion12from the first air supply passage13. As illustrated inFIGS. 13 and 14, the first air discharge ports16are provided on the both left and right sides of the respective discharge electrodes21as viewed from the blow-off opening11side. The ejected air is ejected forward from the first air discharge port16at a high speed. The working effect obtained by providing the first air discharge port16will be described below in detail.

Referring back oFIG. 9, an air guide member17is located at the upper part of the first air discharge port16to cover the upper front side of the first air discharge port16. The air guide member17increases straightness of the ejected air blown from the first air discharge port16. The ejected air guided by the air guide member17is ejected toward opening portions22formed in a groove shape on the periphery of the discharge electrode21. The working effects of the ejected air guided by the air guide member17will be described below in detail.

Referring again toFIG. 9, a cover14is provided at the top of the housing10. The cover14is provided above the first air supply passage13and the discharge electrode unit mounting portion12, that is, on an opposite side of the discharge electrode21with the counter electrode23interposed therebetween.

As illustrated inFIG. 10, an air flow path15is formed among the cover14, the first air supply passage13, and the discharge electrode unit mounting portion12. The air flow path15penetrates from the rear surface to the front surface of the housing10, and is formed to be substantially parallel to the direction in which the air guide member17guides the ejected air. That is, the direction of the ejected air flow discharged from the first air discharge port16is the same as the direction of air flow flowing through the air flow path15. The air flow path15abuts against the upper surface of the discharge electrode unit20assembled to the housing10. As illustrated inFIGS. 2 and 5, an intermediate portion of the cover14is reinforced by reinforcing ribs14A that are disposed in the housing10at intervals in the width direction.

As illustrated inFIGS. 2, 5, and 9, an inlet-hole15A on the back side of the air flow path15is formed in a curved shape by the upper portion of the air guide member17. Thus, the inlet-hole15A on the back side of the air flow path15extends rearward. As a result, the outside air in the rear of the ion generator1is easily taken into the air flow path15.

In addition, an opening area of the blow-off opening11of the ion generator1is the gross area of an opening area of the front surface of the air flow path15, and an opening area of the opening portion22.

As illustrated inFIG. 11, a plurality of discharge electrodes21is disposed side by side in the discharge electrode unit20at intervals in the lateral direction (width direction). Here, the four discharge electrodes21are illustrated inFIG. 11, but the number of the discharge electrodes21is not limited thereto. The discharge electrode21is formed in a thin linear shape or in a needle shape. In the state of mounting the discharge electrode unit20to the discharge electrode unit mounting portion12, the discharge tip21P of the discharge electrode21linearly extends toward the blow-off opening11on the front side. Moreover, groove-like opening portions22are formed on an upper portion of a counter electrode support220, at positions corresponding to the positions of each of the discharge electrodes21. The opening portion22penetrates in a front-to-back direction, and the top thereof is opened. Each of the discharge electrodes21is exposed to the outside from the upper surface of the counter electrode support220via the opening portion22.

As illustrated inFIGS. 9, 11 and 12, the counter electrode23is mounted to the discharge electrode unit20, on the upper side of the position spaced rearward from the discharge tip21P of the discharge electrode21by a predetermined distance. The counter electrode23is formed in a strip shape that is continuous in the longitudinal direction of the discharge electrode unit20.

As illustrated inFIG. 12, the discharge electrode unit20has a discharge electrode support210, and a counter electrode support220. And, the counter electrode23is able to mount without difficulty on the counter electrode support220of the discharge electrode unit20. The counter electrode23is mounted on the upper side of the position spaced rearward from the discharge tip21P of the discharge electrode21by a predetermined distance.

The discharge electrode support210is formed by a rectangular printed circuit board. A discharge electrode holder211configured to hold the discharge electrode21is fixed to the upper surface of the printed circuit board, at a predetermined interval in the longitudinal direction. A pattern212provided on the printed circuit board is connected to each discharge electrode21.

The counter electrode support220has approximately the same length as that of the discharge electrode support210, and is formed of an insulating material such as synthetic resin. At both longitudinal ends of the counter electrode support220, recesses221into which both longitudinal ends of the counter electrode23to be described later can be fitted are formed. An air guide opening portion222forming at least a part of the opening portion22is formed at positions corresponding to each of the discharge electrodes21of the discharge electrode support210. The air guide opening portion222is formed by an opening edge223. The opening edge223is an annular shape and formed as the lower side open. A flat roof-like spacer224covering the rear part of the upper surface of the air guide opening portion222is formed at the rear part of the opening edge223. Recesses224aare formed on the upper surface of the spacer224, and the counter electrode23can be fitted to the recesses224a. The spacer225has a thin rib shape and is provided between the spacers224adjacent to each other. Moreover, the height of the spacer225from the upper surface of the counter electrode support220is the same as the height of the spacer224from the upper surface of the counter electrode support220. Recesses225aare formed in the upper end portion of the spacer225. The counter electrode23can be fitted to the recesses225a. The recesses221, the recesses224a, and the recesses225aare positioned on the common horizontal plane.

The counter electrode23is formed of a metal plate having conductivity. The surface of the counter electrode23is covered with an insulating material or an insulating film. As illustrated inFIGS. 11 and 12, fixing portions231are formed at both ends in the longitudinal direction of the counter electrode23and are extended in a direction perpendicular to the longitudinal direction.

The discharge electrode unit20having the above-described configuration can be assembled in the following manner. First, the discharge electrode support210is brought close to the lower side of the counter electrode support220, while making the discharge electrode support210and the counter electrode support220in a parallel state. Subsequently, at least one of the discharge electrode support210and the counter electrode support220is moved in the parallel direction such that each of the discharge electrodes21is positioned at the center of each air guide opening portion222of the counter electrode support220. Then, the upper surface of the discharge electrode support210is caused to abut against the lower surface of the counter electrode support220, thereby positioning the discharge electrode21at a predetermined position.

In this state, the fixing portions231at both ends of the counter electrode23are fixed by being fitted into the recesses221at both ends of the counter electrode support220. Alternatively, holes232are provided at both ends of the counter electrode23, and the fixing portions231are fixed by being screwed into the counter electrode support220through the holes232. When the fixing portions231of the counter electrode23are fixedly fitted to the recesses221of the counter electrode support220, the counter electrode23is supported by the recesses224aand225ain a horizontal state. Accordingly, the shortest distances from the respective discharge electrode21to the counter electrode23are all the same, and discharge capability of each of the discharge electrodes21is the same.

After mounting the counter electrode23to the counter electrode support220, a bottom member230is fixed to the bottom surface of the counter electrode support220, and the bottom of the air guide opening portion222of the counter electrode support220is closed. When the discharge electrode support210is fixed to the counter electrode support220, it is not necessary to use the bottom member230.

As illustrated inFIG. 9, in the state in which the discharge electrode unit20is assembled to the housing10, an ejected air flow path24is formed inside the discharge electrode unit20. The ejected air flows toward the opening portion22from the front side of the first air discharge port16through the ejected air flow path24. Thus, the ejected air discharged from the first air discharge port16is sent to the opening portion22through the ejected air flow path24, flows between the counter electrode23and the discharge electrode21, and is ejected forward from the blow-off opening11. Accordingly, the air ions generated between the discharge electrode21and the counter electrode23are efficiently ejected forward by the ejected air.

Referring again toFIG. 9, a spacing portion26is provided between the front leading end portion of the air guide member17and the trailing end portion of the ejected air flow path24. As described above, the ejected air from the first air discharge port16flows through the ejected air flow path24at a high speed. Moreover, in the spacing portion26and the opening portion22, the ejected air flowing at a high speed joins the outside air in the air flow path15.

In addition, as illustrated inFIGS. 1 and 2, the ion generator1is supplied with power source from an external power source via a power cable27. And high voltage is applied between the two electrodes of the discharge electrode21and the counter electrode23incorporated in the discharge electrode unit20. Thus, a corona discharge occurs, and the air ions are generated. Since the structures of an internal wiring, a circuit configuration and the like for supplying the power source (not illustrated) are well known, the detailed description thereof will not be provided.

Next, the operation of the ion generator1according to the embodiment will be described with reference toFIGS. 9 and 10. The compressed air supplied from the air supply port13A (FIGS. 6 and 8) of the housing10flows into the first air supply passage13, and is blown out from the first air discharge port16. Moreover, the blown ejected air flows into the opening portion22in which the discharge electrode21and the counter electrode23faces each other, through the ejected air flow path24, and is blown out from the blow-off opening11, together with the air ions generated by the corona discharge.

The high-speed ejected air blown from the first air discharge port16takes in the outside air at the air flow path15or the rear part of the ion generator1via the spacing portion26, thereby generating the flow of outside air different from the flow of ejected air. More particularly, the flow of the ejected air comes into contact with the outside air in the vicinity of the opening portion22of the discharge electrode unit20. Moreover, the outside air is taken in the flow of ejected air. Thus, the outside air flows along the flow of the ejected air.

As illustrated inFIG. 15B, a counter electrode23′ is formerly disposed on the front side of or around the discharge tip of the discharge electrode21′. In contrast, in the present invention, illustrated inFIG. 15A, the counter electrode23is disposed at a position spaced rearward from a discharge tip21P of the discharge electrode21by a predetermined distance D1and upward by a predetermined distance D2. In the present invention, the electric field intensity generated between the discharge electrode21and the counter electrode23is approximately 10 to 20% low compared to the electric field intensity generated between the discharge electrode21′ and the counter electrode23′.

However, the counter electrode23is located on the upstream side of the flow of ejected air with respect to the discharge electrode21. Thus, in the total amount of air ions generated around the discharge tip21P of the discharge electrode21, the amount adsorbed to the counter electrode23is small. More specifically, the corona discharge occurs in the space between the discharge tip21P of the discharge electrode21and the counter electrode23provided behind the discharge tip21P. The air flows toward the front from the discharge tip21P of the discharge electrode21. Therefore, the air ions do not flow rearward from the discharge tip21P, that is, to the upstream side of the flow of air. As a result, in the total amount of air ions, the amount adsorbed to the counter electrode23is small.

Since the counter electrode23is covered with an insulating film, current due to air ions does not flow to the counter electrode23. And, since the counter electrode23is not grounded via a resistor, the potential of the counter electrode23does not change. As a result, since the electric field intensity between the discharge electrode21and the counter electrode23does not change so much, it is possible to suppress a change in the generation amount of air ions. Therefore, it is possible to carry the air ions to the target without disturbing the balance between the air ions. That is, it is possible to increase a conveyance amount of ion without affecting the generation amount of air ions.

As described above, the present invention can have a configuration in which air effectively flows. The outside air flowing into the ion generator1is blown off together with the air ions generated by the discharge electrode21, by coming contact with the discharge electrode21at the opening portion22of the discharge electrode unit20. At this time, the counter electrode23is disposed on the upper side of the discharge electrode21. Therefore, the taken outside air is blown out, while passing through the upper portion of the discharge electrode21, and while taking the air ions to be generated in the discharge electrode21. In this way, since the air volume of outside air is applied in addition to the air volume of the ejected air to be blown out, an amount of ion-conveying air is amplified.

The cover14of the housing10also has a function of regulating the flow of the taken outside air. That is, since the flow of outside air flowing into the air flow path15is regulated by the cover14, turbulence does not occur. If the turbulence occurs, the positive air ions and the negative air ions are neutralized each other by mixing of turbulence. However, since it is possible to prevent the occurrence of turbulence by the cover14, it is possible to reduce the neutralization of the air ions. Furthermore, when the turbulence occurs, straightness of the flow of outside air is lost. Moreover, the flow rate of the outside air is lowered. The cover14can prevent these problems.

The ion generator1has the air guide member17that guides the ejected air blown out from the first air discharge port16toward the opening portion22. Moreover, the ejected air is sent to the opening portion22while remaining at a high speed. As a result, since the outside air is easily taken by the flow of the high-speed ejected air, the ion generator1is able to blow out the ion-conveying air exceeding the flow rate of the ejected air from the blow-off opening11.

The ion generator according to the embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiments, and various modifications and alternations can be made based on the technical idea of the present invention.

For example, in this embodiment, the counter electrode23is provided above the rear part of the discharge electrode21, but the counter electrode23may be provided below the rear part of the discharge electrode21, by reversing a vertical relation between the discharge electrode21and the counter electrode23. Otherwise, the counter electrode23may be formed in an annular shape centered on a rear extension line of the axial center of the discharge electrode21.

In this embodiment, the outside air is sent to flow through the air flow path15so as to be taken into the high-speed ejected air. In contrast, for example, as illustrated inFIG. 16, it is also possible to add a second air supply portion30configured to supply the assist air on the upstream side of the first air discharge port16.

The second air discharge port31of the second air supply portion30is directed toward the air flow path15. The air spouted from the second air discharge port31flows with the outside air to a region (i.e., air ions generating space) where the air ions are generated between the discharge electrode21and the counter electrode23. The air volume of outside air flowing through the air flow path15further increases (assists), by the assist air blown out from the second air discharge port31. As a result, a larger amount of the ion-conveying air (the ejected air, the outside air, and the assist air) is obtained. Furthermore, straightness of the outside air flow is further enhanced by sending the assist air into the air flow path15.

Furthermore, in this embodiment, air, that is, air obtained by combining the ejected air with the outside air, or air obtained by combining the ejected air, the outside air, and the assist air is caused to flow between the discharge electrode21and the counter electrode23, but this flow of air is not always necessary. The flow of air is required when the voltage applied to the discharge electrode is high-frequency AC voltage, but it is not necessary to cause the air to flow when the applied voltage is low-frequency AC voltage.

The counter electrode23is further preferably provided with an insulating material that covers the same. Since the insulating film is easy to be provided, the insulating film is desirably used for the insulating material. When the counter electrode23is covered with an insulating material, since the adsorption of air ions to the counter electrode23is prevented, the electric charge is prevented from being accumulated in the counter electrode23. Erosion of the counter electrode23due to air ions also does not occur. Using the insulating material obtains an effect in which a conveyance amount of air ions generated increases without a decline in the discharge capacity.

The above-described embodiments relates to the ion generator1in which a plurality of the discharge electrodes21is provided in the longitudinal direction, but, in contrast, for example, as illustrated inFIG. 17, the ion generator may be in the form that is provided with one discharge electrode21and one counter electrode23, and blows the air ions to the target in a spot manner. InFIG. 17, members corresponding to the members of the above-described embodiment are denoted by the same reference numerals.

Although various embodiments of the present invention have been described and shown, the invention is not restricted thereto, but may also be embodied in other ways within the scope of the subject-matter defined in the following claims.