JP6481160B2 - Static eliminator - Google Patents

Description

  The present invention relates to a static eliminator for neutralizing the surface of a sheet-like charged object that moves in a certain direction.

Conventionally, a static eliminator shown in Patent Document 1 using an AC discharge electrode and an auxiliary electrode opposed to the surface of a sheet charged with a mixture of fine and negative charges is known.
As shown in FIG. 5, the conventional static eliminator is applied with a plurality of positive and negative discharge electrodes 2 that alternately discharge positive ions and negative ions from the upstream side along the moving direction of the sheet 1, and a negative voltage is applied. The 1st static elimination electrode 3, the 2nd static elimination electrode 4 to which a positive voltage is applied, and the alternating current static elimination electrode 5 are provided in order.
The positive / negative discharge electrodes 2, the static elimination electrodes 3 and 4, and the AC static elimination electrode 5 are bar-shaped electrodes each having a length across the width of the sheet 1, and a plurality of electrode needles (not shown) are arranged on a straight line. .

A plate-like auxiliary electrode 6 is provided at a position facing the plurality of positive and negative discharge electrodes 2 with the sheet 1 interposed therebetween. The auxiliary electrode 6 has a width facing all of the plurality of positive and negative discharge electrodes 2.
An AC voltage is applied to the discharge electrode 2 to alternately release positive and negative ions, and an AC voltage having a polarity opposite to that of the discharge electrode 2 is applied to the auxiliary electrode.

  On the other hand, positive and negative charges are mixed in a complicated manner on the surface of the sheet 1 which is a charge removal target. For example, as shown in FIG. 6, when positive charges and negative charges are alternately arranged, the electric field is closed between these adjacent charges, and the overall surface potential is zero, that is, apparently charged. It will not be like that. In such a state, even if positive ions or negative ions are emitted using a normal static eliminator, the ions that reach the sheet surface do not work because the sheet surface does not have an attractive force to attract ions emitted from the static eliminator. In some cases, the concentration was low and the charge could not be removed sufficiently.

Therefore, in the conventional static eliminator, as shown in FIG. 5, by providing the auxiliary electrode 6 facing the positive and negative discharge electrodes 2 on the back side of the sheet 1, the polarity of the surface potential of the sheet 1 is caused by electrostatic induction phenomenon. The polarity is opposite to that of the positive and negative discharge electrodes 2, and ions emitted from the positive and negative discharge electrodes 2 are attracted to the surface of the sheet 1.
By providing the auxiliary electrode 6 as described above, it is possible to forcibly irradiate the surface of the sheet 1 that is almost neutralized macroscopically with positive and negative ions, and neutralize the complicated charge of positive and negative. , The fine charged pattern can be erased. Note that the fine charge pattern that is, from the pattern corresponding to the positive and negative charge distribution positive and negative charges are formed complexly mixed, e.g., visualized by attaching the like charged preparative toner positively or negatively can do.

As described above, the fine charged pattern disappears from the surface of the sheet 1 that has passed through the facing distance between the positive and negative discharge electrodes 2 and the auxiliary electrode 6, but by forcibly irradiating positive ions and negative ions, the sheet surface In FIG. 1, a striped charged pattern perpendicular to the sheet moving direction is formed as shown in the schematic diagram of FIG. This striped charging pattern is also not visible, and as shown in FIG. 8, a positive charging area a where positive charges are concentrated and a negative charging area b where negative charges are concentrated. Are formed alternately. Such a striped charged pattern can also be visualized by attaching a positively or negatively charged toner, for example.
Note that the sine curve s shown in FIG. 7 shows the surface potential formed by the alternating voltage applied to the discharge electrode 2 and the auxiliary electrode 6, and the surface of the sheet 1 has a charge corresponding to the curve s. Will exist.

  In this conventional apparatus, negative ions are emitted from the first static elimination electrode 3 and positive ions are emitted from the second static elimination electrode 4 toward the surface of the sheet 1 on which the striped charged pattern is formed. Positive and negative ions are neutralized. The AC static eliminator 5 provided on the downstream side in the moving direction of the sheet 1 is for neutralizing the remaining charge on the sheet surface even after passing through the positions of the first and second static elimination electrodes 3 and 4. .

Japanese Patent No. 2651478

In the above-described conventional apparatus, a microscopic charging pattern in which positive and negative are mixed in a complicated manner is removed and a macroscopic striped charging pattern as shown in FIG. 7 is formed, and then a positive charging area a and a negative charging area are formed. b is neutralized. However, in the above-described conventional apparatus, the striped charged pattern may not be sufficiently removed. The reason is considered as follows.
On the surface of the sheet 1 on which the stripe charging pattern is formed, as shown in FIG. 8, a positive charging area a where positive charges are concentrated and a negative charging area b where negative charges are concentrated alternately. Is formed.
When, for example, the ions e1 are emitted from the first static elimination electrode 3 above the sheet 1, the negative ions e1 are attracted to the positive charges in the positive charging area a as shown in FIG. Neutralize. In the central portion of the positive charging area a, positive charges are particularly concentrated, and since the potential is high, the attractive force for the negative ions e1 increases, and the amount of the negative ions e1 reaching the surface of the sheet 1 increases. Will increase.

On the other hand, a repulsive force acts between the negative charging area b and the negative ion e1, and the negative ion e1 does not reach the negative charging area b of the sheet 1.
Similarly, the positive ions e2 released from the second static elimination electrode are attracted to the negative charges in the negative charging region b, but repel between the positive charging regions a. Also in this negative charged region b, since negative charges are concentrated in the central portion as compared with the boundary portion c with the positive charged region a, more positive ions e2 reach the central portion. .
However, in the boundary portion c between the positive and negative charging regions a and b, the adjacent charges form an electric field that is closed, so that the negative ions e1 and positive ions e2 emitted from the first and second static elimination electrodes 3 and 4 No attractive force acts between them, and these ions e1 and e2 hardly reach the boundary c. For this reason, the boundary portion c is not neutralized and surface charges may remain in a narrow portion. Although the charged portion left in this way is slight, for example, the wettability of the portion on the sheet surface may be deteriorated, which may cause uneven coating.

  It is an object of the present invention to include surface charges of a sheet-like charged object in which positive and negative charging areas are alternately arranged and a striped charging pattern is formed, including the boundary between the positive and negative charging areas. It is another object of the present invention to provide a static eliminator capable of reliably eliminating static electricity over the entire surface.

The present invention provides a discharge electrode that alternately discharges positive ions and negative ions toward one surface of a sheet-like charged object that is continuous in the moving direction, and a position that faces the discharge electrode across the charged object. A plate-like auxiliary electrode that attracts ions discharged from the discharge electrode to the charged object side, and crosses the moving direction on one surface of the charged object that has passed between the discharge electrode and the auxiliary electrode. An electric field in which a positive charge area in which positive charges are concentrated and a negative charge area in which negative charges are concentrated is alternately repeated in a stripe pattern, and adjacent positive and negative charges are closed. It is premised on a static eliminator in which a stripe-shaped charged pattern having a boundary portion for forming a pattern is formed.

Assumes the neutralization apparatus, this invention is in the downstream side in the moving direction of the charged objects than between opposing portions of the discharge electrodes and the auxiliary electrode is provided with a length of at least the width of the above charged object A bar-shaped first static elimination electrode that maintains a positional relationship that intersects the moving direction of the charged object and that is applied with either a positive or negative DC voltage and emits ions toward the one surface of the charged object; A bar-shaped first ion attracting electrode having at least the same length as the first charge eliminating electrode and to which a voltage having a polarity opposite to that of the first charge eliminating electrode is applied is disposed opposite to the charged object.

Further, a position that is at least the width of the charged object and that crosses the moving direction of the charged object is maintained downstream of the first static elimination electrode in the moving direction of the charged object, and the first object. A bar-shaped second static elimination electrode that applies a DC voltage having a polarity opposite to that of the static elimination electrode and emits ions toward the one surface of the charged object, and has at least the same length as the second static elimination electrode, (2) A charge-removing electrode and a bar-shaped second ion-sucking electrode to which a reverse polarity voltage is applied are arranged opposite to each other with the charged object interposed therebetween. A plurality of electrode needles are arranged on a straight line, and the electrode needles of the first and second static elimination electrodes and the electrode needles of the first and second suction electrodes facing each other through the charged object are substantially facing each other .

Further, on the downstream side than the second neutralizing electrode along the movement direction of the charging object is connected to an AC power source, a third neutralizing electrode that emits positive ions and negative ions alternately on one side the The boundary portion of the striped charged pattern formed on one surface of the charged object is formed by opposing the ions discharged from the first and second static elimination electrodes and attracted to the first and second ion suction electrodes. And the third charge removal electrode emits positive and negative ions toward the one surface.

According to the present invention, a macroscopic lens formed by alternately and repeatedly forcibly irradiating positive and negative ions for a certain period of time on a sheet-like charged object that is charged and moved with a mixture of fine and negative charges. Positive and negative ions can be forcibly made to reach the boundary between the positive charging area and the negative charging area of the striped charged pattern by the first and second ion attracting electrodes. As a result, the charges on the entire surface including not only the central portion of the positive and negative charging regions constituting the stripe-shaped charging pattern but also the boundary portion can be reliably removed.
In the case where there are still slightly charges the surface of the charging object can also be a third neutralizing electrode in a short time repeatedly positive and negative ion irradiation on one side above, removing charge was Tsu remaining .

FIG. 1 is an overall configuration diagram of a static eliminator according to an embodiment of the present invention. FIG. 2 is a diagram showing the relationship between the first and second static elimination electrodes and the first and second ion attraction electrodes according to the embodiment. FIG. 3 is a cross-sectional view of the sheet 1 in the first static elimination electrode portion on a plane orthogonal to the moving direction. FIG. 4 is a schematic diagram for explaining the state of charge on the sheet surface when the stripe-shaped charging pattern is formed, and the static elimination mechanism in the embodiment. FIG. 5 is a configuration diagram of a conventional static eliminator. FIG. 6 is a schematic diagram showing a state of the sheet surface on which a fine charged pattern is formed. FIG. 7 is a plan view of a sheet on which a striped charged pattern is formed. FIG. 8 is a schematic diagram for explaining the state of electric charge on the sheet surface when the stripe-shaped charging pattern is formed and the static elimination mechanism in the conventional static eliminator.

An embodiment of the present invention will be described with reference to FIGS.
The neutralization device of this embodiment is a device for neutralizing the surface of the sheet 1 that moves in one direction. As shown in FIG. 1, the neutralization device of the sheet 1 that is on the side facing the surface that is one surface of the sheet 1. A plurality of positive and negative discharge electrodes 2 that are connected to an alternating current power source and alternately discharge positive ions and negative ions in order from the upstream side along the moving direction of the sheet 1, a first static elimination to which a negative voltage is applied An electrode 3, a second static elimination electrode 4 to which a positive voltage is applied, and an AC static elimination electrode 5 that is a third static elimination electrode of the present invention to which an alternating voltage is applied are provided in this order.
The positive and negative discharge electrodes 2, the first, second and third static elimination electrodes 3 and 4 and the AC static elimination electrode 5 are bar-shaped electrodes each having a length straddling the width of the sheet 1, and a plurality of electrode needles are arranged on a straight line. These are the same as the conventional electrodes 2, 3, 4 and 5 shown in FIG.

FIG. 3 shows the arrangement of the electrode needle 3a of the first static elimination electrode 3 and the electrode needle 7a of the first ion attracting electrode 7 to be described later. A plurality of electrode needles (not shown) are provided on a straight line.
In addition, a plate-like auxiliary electrode 6 disposed opposite to the positive and negative discharge electrodes 2 is provided on the lower surface side of the sheet 1, and an AC voltage having a polarity opposite to that of the positive and negative discharge electrodes 2 is applied to the auxiliary electrode 6. By doing so, ions emitted from the positive and negative discharge electrodes 2 are attracted to the surface of the sheet 1 as in the conventional case.

However, in this embodiment, a first ion attracting electrode 7 is provided on the downstream side of the auxiliary electrode 6 in the moving direction of the sheet 1 at a position almost directly facing the first neutralizing electrode 3, and the second neutralizing electrode 4 The second ion attracting electrode 8 is provided at a position almost directly opposite.
As shown in FIG. 3, the first ion attracting electrode 7 includes a plurality of electrode needles 7 a installed at predetermined intervals in the width direction of the sheet 1, and each of these electrode needles 7 a includes the first charge eliminating electrode. The electrode 3 faces the electrode needle 3a.
A positive voltage is applied to the first ion attraction electrode 7 to form an electric field as indicated by a broken line from the electrode needle 7a of the first ion attraction electrode 7 toward the electrode needle 3a of the first charge elimination electrode 3. I try to do it.

A second ion attracting electrode 8 is provided downstream of the first ion attracting electrode 7 in the moving direction of the sheet 1. Similar to the first ion attraction electrode 7, the second ion attraction electrode 8 includes a plurality of electrode beams 8 a that are directly opposed to the electrode beam 4 a of the first charge removal electrode 4.
Then, a negative voltage is applied to the second ion attracting electrode 8 so that an electric field from the electrode needle 4a to 8a is formed (see FIG. 2).

The effect | action in which the static elimination apparatus of this embodiment described above neutralizes the surface of the sheet | seat 1 is demonstrated below.
When the sheet 1 in which positive and negative charges are mixedly mixed on the surface and a fine charged pattern is formed passes between the positive and negative discharge electrodes 2 and the auxiliary electrode 6, as described above, as shown in FIG. A striped charged pattern is formed. When the sheet 1 in this state moves and enters between the first static elimination electrode 3 and the first ion attraction electrode 7, the negative ions e1 emitted from the first static elimination electrode 3 cause stripes on the surface of the sheet 1. The positive charge in the positive charging area a forming the charged pattern is removed. Since a lot of positive charges are collected in the positive charging area a, the positive charge mass attracts the negative ions e1. As a result, the negative ion e1 reaches the positive charge in the positive charging area a and neutralizes it.

In addition, at the boundary c between the positive charging area a and the negative charging area b, the positive charge and the negative charge are adjacent to each other, and an electric field in the direction of the arrow is formed as shown in FIG. Originally, the positive charge at the boundary c does not exert almost all the attractive force that attracts the negative ions e1. However, in this embodiment, the ion attracting electrode 7 is provided and an electric field is formed between the electrode needles 7a and 3a so that the negative ions e1 reach the boundary c. Therefore, the positive charge at the boundary portion c can be easily neutralized by the negative ions e1 (see FIG. 4) .

On the other hand, since a negative charge lump is formed inside the negative charging region b, the negative ions e1 released from the first static elimination electrode 3 repel the negative charge lump and the sheet 1 It hardly reaches the surface.
As described above, the negative ions e1 reach the boundary portion c as described above by the ion attracting electrode 7 and neutralize the positive charges at the boundary portion c, but the adjacent positive charges are in the middle. The negative charge of the summed boundary portion c repels the negative ions e1 in the same manner as the negative charge of portions other than the boundary portion c.
As described above, most of the positive charges are removed from the surface of the sheet 1 which has moved between the opposing surfaces of the negative ion e1 and the first discharging electrode 3 and the first ion attracting electrode 7, and only the negative charge remains. It will be. That is, the surface of the sheet 1 has a striped shape in which the negatively charged regions b and the neutralized regions are alternately arranged.

Next, when the sheet 1 reaches between the second static elimination electrode 4 and the second ion suction electrode 8, the positive ions e2 released from the second static elimination electrode 4 are left on the sheet 1 this time. The negative charge on the negative charging region b is attracted to the second ion attracting electrode 8 to which a negative voltage and a negative voltage are applied, and the negative charge on the sheet 1 is neutralized.
Since the positive charge is almost neutralized by the first static elimination electrode 3 in the sheet 1, the surface of the sheet 1 is almost the same if the negative charge is neutralized by the positive ions e2 emitted from the second static elimination electrode 4. It will be completely neutralized.

As described above, by providing the first ion attracting electrode 7, the negative ions e1 are forced to reach the boundary c where the positive and negative ions are difficult to reach to neutralize the positive charges. Even if the first ion attraction electrode 7 is provided, a slight positive charge may remain at the boundary c on the sheet 1.
In this way, at the boundary c where the positive charge remains, the force to attract the positive ions e2 emitted from the second static elimination electrode 4 is weak, but in this embodiment, the second ion attraction electrode facing the second static elimination electrode 4 Since the negative voltage is applied to 8, the positive ions e2 can be forcibly moved to the sheet 1 side (see FIG. 2). As a result, the negative charges on the sheet 1 are almost completely neutralized by the positive ions e2 from the second static elimination electrode 4.
Since the amount of positive charge remaining after passing between the first static elimination electrode 3 and the first ion attraction electrode 7 is small, the attraction force that attracts the positive ions e2 by the second ion attraction electrode 8 is the first ion attraction electrode. It does not have to be as strong as 7.

The slight charge that cannot be removed by the first and second neutralization electrodes 3 and 4 and the first and second ion attracting electrodes 7 and 8 can be eliminated by the AC neutralization electrode 5 provided further downstream. .
However, by optimally adjusting the voltages of the electrodes 3, 4, 7, and 8, the distance between the first charge eliminating electrode 3 and the first ion attracting electrode 7, and the second charge eliminating electrode 4 and the second ion attracting electrode 8 are set. The charge remaining on the sheet 1 that has passed between them can be almost eliminated. In that case, the AC neutralizing electrode 5 may not be provided.
As described above, according to the static eliminator of this embodiment, the positive and negative of the sheet 1 in which the positive and negative charging areas a and b constituting the striped charging pattern are alternately formed by the positive and negative discharge electrodes 2 and the auxiliary electrode 6. The entire region including the boundary portion c between the charged regions a and b can be completely neutralized.
As described above, if the surface of the sheet 1 can be completely neutralized, for example, the wettability can be varied by the remaining charged portion, and coating unevenness does not occur.

Contact name in the above embodiment, the electrode needle 3a of the first and second charge removing electrodes 3, 4, 4a and the electrode needles 7a of the first and second ion attracting electrode 7,8, and an 8a is confronting.

  In the above embodiment, a negative voltage is applied to the first static elimination electrode 3 and a positive voltage is applied to the second static elimination electrode 4. However, a positive voltage is applied to the first static elimination electrode 3. A negative voltage may be applied to the second static elimination electrode 4. In that case, the negative charging area b on the sheet 1 is neutralized by positive ions released from the second static elimination electrode 4, and then the positive charging area a by negative ions emitted from the second static elimination electrode 4. Will be neutralized. In short, the voltage applied to the first and second static elimination electrodes 3 and 4 may be either positive or negative as long as they have opposite polarities. The polarities of the first and second ion attracting electrodes 7 and 8 may be opposite to those of the first and second neutralizing electrodes 3 and 4.

  The present invention is suitable for discharging a sheet-like charged object that is easily charged, such as a resin film.

DESCRIPTION OF SYMBOLS 1 Sheet 2 Positive / negative discharge electrode 3 1st static elimination electrode 4 2nd static elimination electrode 5 AC neutralization electrode 6 (it is the 3rd static elimination electrode) Auxiliary electrode 7 1st ion attraction electrode 8 2nd ion attraction electrode a Positive charging area b Negative Charging range e1 Negative ion e2 Positive ion

Claims (1)

A discharge electrode that alternately emits positive ions and negative ions toward one surface of a sheet-like charged object continuous in the moving direction;
A plate-like auxiliary electrode provided at a position facing the discharge electrode across the charged object, and attracting ions emitted from the discharge electrode to the charged object side;
On one surface of the charged object that has passed between the discharge electrode and the auxiliary electrode, there are a positive charging area where positive charges are concentrated and a negative charging area where negative charges are concentrated. In the static eliminator in which a stripe-shaped charging pattern having a boundary portion that forms an electric field in which adjacent positive charges and negative charges are closed is alternately repeated in a stripe pattern,
On the downstream side in the moving direction of the charged object than between the opposed portions of the discharge electrode and the auxiliary electrode,
The charged object has a length corresponding to at least the width of the charged object and maintains a positional relationship that intersects the moving direction of the charged object, and a positive or negative DC voltage is applied toward the one surface of the charged object. A bar-shaped first discharging electrode that emits ions, and a bar-shaped first ion-sucking electrode that has at least the same length as the first discharging electrode and is applied with a voltage of a polarity opposite to that of the first discharging electrode. , Oppositely placed across the charged object,
On the downstream side in the moving direction of the charged object from the first static elimination electrode,
The charged object has a length corresponding to at least the width of the charged object and maintains a positional relationship that intersects the moving direction of the charged object, and a DC voltage having a polarity opposite to that of the first charge eliminating electrode is applied to the one surface of the charged object. A bar-shaped second static elimination electrode that emits ions toward the surface, and a bar-shaped second ion attraction electrode that has at least the same length as the second static elimination electrode and is applied with a voltage having a polarity opposite to that of the second static elimination electrode And facing each other across the charged object,
The first and second static elimination electrodes and the first and second ion attraction electrodes are each formed by arranging a plurality of electrode needles on a straight line, the electrode needles of the first and second static elimination electrodes facing each other through the charged object, The electrode needles of the first and second suction electrodes are almost directly facing,
Further, a third static elimination electrode connected to an AC power source and emitting positive ions and negative ions alternately on the one surface is provided downstream of the second static elimination electrode along the moving direction of the charged object. Provided facing each other,
Ions discharged from the first and second static elimination electrodes and attracted to the first and second ion attraction electrodes neutralize the charges at the boundary portions of the striped charged pattern formed on one surface of the charged object. In addition, a static eliminator configured such that the third static elimination electrode emits positive and negative ions toward the one surface .

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