JP2019067733A - Static elimination method and apparatus - Google Patents

Abstract

To completely remove a charge even from a removal target that is difficult to remove charges because the charges are easily accumulated inside such as a multilayer sheet in a short time without causing damage.SOLUTION: A static elimination apparatus includes a vacuum chamber 5, transport means 14 for transporting a static elimination object 1 in a vacuum chamber 5, ion irradiation means 17 and 18 for irradiating the static elimination object 1 with ions, and discharge means 21 and 22 provided on the downstream side of the ion irradiation means 17 and 18 in the transport direction of the static elimination object 1, and the discharge means 21 and 22 are brought into contact with or close to the static elimination object 1 to cause the charge of the static elimination object 1 to flow to the ground side.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a static elimination method and apparatus for static elimination of a static charge target, such as a sheet subjected to digital printing and charged, to the inside.

Conventionally, there is a printing system which performs printing on a sheet-like print target using digital technology without creating a printing plate (see Patent Document 1). The sheet printed by this type of printing machine is charged.
When one sheet is charged, the positive and negative charges on both sides form a closed electric field, so there is no problem. However, when the sheet is discharged from the printing machine and stacked on the tray T, as shown in FIG. 4, the charges on both sides of the sheet 1 are not closed via the thickness of one sheet 1 but are stacked. Combine the upper and lower sheets 1 and 1 together. This is because the distance between the upper and lower sheets 1 and 1 in contact with each other is smaller than the thickness of the sheet 1.

Therefore, a strong suction force is generated between the stacked sheets 1 and 1 due to the coulomb force, and the sheets 1 and 1 are stuck to each other.
In FIG. 4, the thickness of the sheet 1 is shown to be large for the sake of explanation, but in practice, the thickness of the sheet 1 is about several tens of [μm] to 1 [mm].
As a result, it becomes difficult to peel off the sheet 1 one by one, which causes a problem that the subsequent processes such as folding, cutting, bookbinding and the like do not proceed smoothly.
Therefore, it is necessary to provide a diselectrification step in the post-process of digital printing.
As the charge removal method, a method of neutralizing the surface charge by irradiating positive and negative ions generated by corona discharge on the surface of the sheet 1 is often used.

International Publication No. 2016/013436 gazette JP, 2008-004397, A

As described above, it has been conventionally known to provide a charge removal step as a post-process of digital printing, but when the charge amount of the sheet 1 is high or the charge is accumulated to the inside of the sheet 1, the above Such an existing charge removal method takes a long time for charge removal or fails to completely remove the charge.
In the case of a multilayer sheet, in particular, charges tend to be accumulated at the boundaries of different materials, and it has been difficult to remove them.

For example, as shown in FIG. 5, in the case where the sheet 1 is a multilayer composed of a paper layer 1a, an aluminum vapor deposition layer 1b and a resin layer 1c, the aluminum vapor deposition layer when charged internally due to the influence of a strong electric field in a digital printing machine. 1b polarizes and attracts the charges of the upper and lower resin layers 1c and the paper layer 1a. Such internal charge was difficult to remove even when the surface was irradiated with ions.
Therefore, the charge amount of the sheet 1 can not be reduced, and when the sheet 1 in such a charged state is stacked, the sheets 1 are electrostatically attracted as shown in FIG.

In order to discharge such a sheet 1 that is difficult to discharge, it is necessary to take time and effort, such as repeating ion irradiation many times, and processing efficiency is deteriorated.
In addition, there is also a problem that the size of the charge removal apparatus is increased because the charge removal process is repeated.
As described above, even when ion irradiation was repeated, practically complete elimination was hardly possible.

On the other hand, as described above, as a method of removing the charge which is difficult to be discharged by accumulating inside, the ground electrode is brought close to the charged sheet 1 under a dischargeable vacuum, and the charge inside from the end face of the sheet 1 is grounded. There is a conceivable way to discharge the And according to this method, not only the charge in the sheet 1 charged to a high potential, but also the charge on the surface can be removed.
However, when the entire charge amount of the sheet 1 is very high, a large amount of electric charge flows at once with the ground electrode to generate a discharge, and even if the charge can be eliminated, the sheet 1 is damaged by the discharge. Sometimes. Specifically, a hole or a crack is formed in the sheet 1.
An object of the present invention is to provide a static elimination method and static elimination apparatus capable of complete static elimination in a short time without giving damage to a static elimination target such as a multilayer sheet in which charges are easily accumulated and hard to be eliminated. It is.

  In the charge removal method according to the first aspect of the present invention, an ion irradiation step of irradiating ions in a vacuum chamber, and after the ion irradiation, the discharge means and the charge removal object are brought into contact or close to each other to charge the charge removal object. And a discharge step of flowing to the ground side through the

According to a second aspect of the present invention, there is provided a charge removal apparatus comprising: a vacuum chamber; a transfer means for transferring a charge removal object in the vacuum chamber; an ion irradiation means for irradiating ions to the charge removal object; Discharge means provided on the downstream side of the conveyance direction of the object;
The discharge means and the object to be neutralized are brought into contact with or in proximity to each other so that the charge of the object to be neutralized flows to the ground side.
In addition, the vacuum in the said vacuum chamber is a vacuum degree with which discharge is most likely to occur, for example, a pressure of about 1 to 5000 [Pa].

  According to a third aspect of the present invention, the discharge means comprises a ground electrode in contact with or in proximity to the object to be discharged in the transport path of the object to be discharged.

  In a fourth aspect of the invention, the ground electrode constituting the discharge means comprises a pair of ground rollers sandwiching the object to be discharged, and charges the charge from the object to be discharged passing between the pair of ground rollers to the ground side I have a configuration.

  According to a fifth aspect of the invention, the pair of ground rollers have a length equal to or greater than the width of the object to be neutralized.

  According to a sixth aspect of the present invention, the outer peripheral portion of the pair of ground rollers excluding the portion contacting the transport path of the object to be neutralized is covered with an electrically insulating material.

  According to a seventh aspect of the present invention, the above-mentioned ion irradiation means is disposed opposite to each other via the transport path of the charge removal object, and includes a pair of discharge electrodes to which a voltage of reverse polarity is applied. The rest is covered with electrical insulation.

  An eighth aspect of the invention relates to a supply port for supplying the charge removal target object to the vacuum chamber, a discharge port for discharging the charge removal target object, and transport means for transferring the charge removal target object from the supply port to the discharge port. The supply port and the discharge port are provided with a seal mechanism which enables the movement of the object of static elimination while preventing the entry of the outside air.

  In a ninth aspect of the invention, the vacuum chamber is a main chamber, and at least one sub-chamber is disposed in series upstream and downstream of the main chamber with respect to the transport direction of the charge removal target. A transfer means is provided for transferring the object of charge removal from the most upstream sub-chamber to the most downstream sub-chamber, and a vacuum realization means is connected to each sub-chamber, and a supply port and an outlet for the charge removal object. The supply port and the discharge port are provided with a seal mechanism which enables the movement of the object of static elimination while preventing the entry of the outside air.

  In a tenth aspect of the invention, the seal mechanism provided at the supply port and the discharge port of the main chamber and sub chamber comprises a pair of seal rollers at least the surface of which is formed of an elastic member, and the seal rollers rotate The drive mechanism is connected.

  In an eleventh aspect of the invention, a guide member formed of an electrically insulating material is provided in the vacuum chamber along the transport path of the object to be neutralized.

According to the present invention, the surface charge is neutralized by irradiating the ions generated in the vacuum chamber to reduce the charge amount of the entire object to be neutralized to some extent, and then the charge remaining by the discharging means is grounded. It can be drained almost completely.
Moreover, since the total charge amount of the object to be eliminated is decreased by neutralization with ions before discharging by the discharge means, the amount of current flowing at once in the discharge is not so large and the object to be eliminated is damaged by the discharge There is no such thing.
In particular, since the inside of the vacuum chamber is easily discharged, a large number of ions are generated in the ion irradiation step, and neutralization by the ion irradiation is rapidly performed.
In addition, since the environment between the object to be neutralized and the discharging means is likely to occur, complete neutralization can be performed in a short time.

  In the third invention, since the ground electrode is provided under a vacuum, discharge from the object to be eliminated tends to occur, and the elimination of electricity in a short time becomes possible.

According to the fourth aspect of the present invention, since the ground roller, which is the ground electrode, is rotated, the distance between the object to be neutralized and the ground electrode can be minimized with the object to be transported being interposed. Since the distance between the object of charge removal and the ground electrode is minimized, the charge removal effect is enhanced.
If the non-rotating ground electrode is brought into contact with the object to be neutralized under vacuum, the frictional resistance is too large to transport the object to be neutralized. On the other hand, if it is attempted to maintain a slight gap between the transported static elimination target and the ground electrode, gap management becomes difficult.
Therefore, a rotating ground roller is most suitable as the discharging means for discharging while conveying the object to be discharged.
As described above, since the charge can be removed while conveying the charge removal target, the charge removal processing speed is increased.

  According to the fifth aspect of the present invention, the entire width of the static elimination target contacts the ground roller, so discharge from the end face of the static elimination target tends to occur, and the static elimination processing speed is increased.

According to the sixth invention, it is possible to prevent the ions generated by the ion irradiation means from being absorbed by the ground roller. Therefore, the generated ions are efficiently irradiated to the static elimination target, and the charge can be neutralized.
Also, if the ground roller is exposed in the transport path of the object to be discharged, the charged object to be discharged may be attracted and stuck to the surface of the ground roller by the charge. If the object to be neutralized is stuck to the surface of the ground roller, it may not be held between the pair of ground rollers, and it may also be possible to transport and neutralize. However, according to the present invention, it is possible to prevent the static elimination object with remaining charge from sticking to the ground roller before being pinched by the ground roller.

  According to the seventh invention, the discharge between the opposing discharge electrodes can be concentrated in the direction toward the charge removal target, and the ion generation region can be made to correspond to the transport path of the charge removal target. Therefore, the generated ions are efficiently irradiated to the static elimination target.

  According to the eighth aspect of the invention, since the object to be neutralized can be supplied or discharged while maintaining the degree of vacuum in the vacuum chamber, continuous static elimination processing can be performed.

According to the ninth aspect, the object to be neutralized is supplied to the main chamber through the subchamber and discharged to the outside through the subchamber, so outside air intrudes from the most upstream supply port and the most downstream outlet. Even if it has little influence on the degree of vacuum of the main chamber. Therefore, the inside of the main chamber can be maintained at an optimal degree of vacuum for discharge.
In particular, the faster the transport speed of the object to be neutralized, the greater the amount of outside air invading from the supply port and the discharge port. However, by providing the sub-chamber, the degree of vacuum of the main chamber can be maintained. You can increase the speed.

  According to the tenth aspect of the invention, the elastic member on the surface of the seal roller is deformed according to the thickness of the object to be discharged and exhibits a sealing function, and the rotating seal roller also functions as a transport means for the object to be discharged.

The guide member of the eleventh invention guides the direction of movement of the static elimination target supplied into the vacuum chamber, and is smoothly transported to the discharge port along the ion irradiation means and the discharge means.
In addition, since the transport path of the object to be neutralized is surrounded by the guide member made of an electrically insulating material, the object to be neutralized can be removed even when there is a grounded body around the transport path such as the discharge means or the inner wall of the chamber. Does not stick to the ground.

It is a block diagram of the static elimination apparatus of embodiment of this invention. It is an enlarged view of the grounding roller vicinity of an embodiment. It is the elements on larger scale showing the state where the sheet was pinched by the grounding roller of an embodiment. FIG. 6 is an explanatory view showing a state in which a charged sheet is stacked on a tray. FIG. 2 is an end view of a charged multilayer sheet.

In one embodiment of the present invention shown in FIGS. 1 to 3, a multilayer sheet 1 as shown in FIG. 5 printed by a digital printing machine is supplied in the arrow x direction in a grounded metal chamber body 2. It is an apparatus which processes continuously.
The inside of the metal chamber body 2 is divided by the partition walls 3 and 4, the center of which is the main chamber 5 which is the vacuum chamber of the present invention, the partition 3 side is the front chamber 6, and the partition 4 side is the rear chamber 7. There is. The front chamber 6 and the rear chamber 7 are sub-chambers of the present invention.
Then, the inside of the main chamber 5 is evacuated by the vacuum pump P1 so that a degree of vacuum of several hundred [Pa] is maintained.
The interiors of the front chamber 6 and the rear chamber 7 are evacuated by a vacuum pump P2 so that the degree of vacuum equal to or lower than that of the main chamber 5 can be maintained.

At the center of the outer wall 8 on the front chamber side 6, an insulating member 10 made of an electrically insulating material such as a fluorine-based resin extending in a direction perpendicular to the paper surface of FIG. 1 is fitted. The insulating member 10 is formed with a slit-like opening 10 a through which the printed sheet 1 can pass. The opening 10 a constitutes a supply port of the front chamber 6.
Insulating members 11, 12, 13 having the same configuration as the insulating member 10 are inserted into the partition walls 3, 4 and the outer wall 9, respectively, and openings 11a, 12a, 13a are formed in each.
The opening 11 a provided in the partition 3 serves as the discharge port of the front chamber 6 and the supply port of the main chamber 5, and the opening 12 a provided in the partition 4 supplies the discharge port of the main chamber 5 and the supply of the rear chamber 7. It also serves as a mouth. Further, the opening 13 a of the outer wall 9 constitutes an exhaust port of the rear chamber 7.

Further, a sealing mechanism 14 is provided adjacent to each of the openings 10a to 13a in the chamber body 2. Among the seal mechanisms 14, the seal mechanism 14 provided adjacent to the partition walls 3 and 4 serves as the seal mechanism provided in the discharge port and the seal mechanism provided in the supply port. Although all the seal mechanisms 14 have the same configuration, the reference numerals of the respective members of the seal mechanisms 14 provided in the chamber main body 2 are omitted.
The seal mechanism 14 is composed of a holder 15 made of resin and a pair of seal rollers 16 and 16 held thereby.
The holder 15 is composed of a pair of holder members 15a and 15b, and the holder members 15a and 15b sandwich and hold the pair of seal rollers 16 and 16.

The pair of seal rollers 16 is provided with an elastic member 16 b such as fluororubber around the outer periphery of a metal rotary shaft 16 a, and is held by the holder 15 so as to be crimped to each other.
Further, in the holder 15, a slit shape having a shape and a size substantially equal to the openings 10a to 13a formed in the insulating members 10 to 13 at positions corresponding to the pressure contact portions of the pair of seal rollers 16. An opening 15c is formed. The opening 15c is continuous with the openings 10a to 13a and serves as a conveyance path of the sheet 1 which is an object of static elimination.

  Furthermore, although an arc-shaped concave portion is formed in the holder 15 in accordance with the outer periphery of the seal roller 16, the curvature of the arc on the holder 15 side is made larger than the curvature of the seal roller 16. The elastic member 16 b is configured to apply a pressing force to the holder 15. Therefore, the outer periphery of the elastic member 16 b is in close contact with the holder 15 to prevent outside air from entering the chamber from between the outer periphery of the seal roller 16 and the holder 15.

Further, a rotation drive mechanism such as a motor is connected to the end in the length direction of the rotation shaft 16a to make the seal roller 16 rotatable. Therefore, the seal mechanism 14 also functions as a transport unit that transports the sheet 1 in the arrow x direction.
When the seal roller 16 rotates, the elastic member 16b slides while pressing the holder. Therefore, the holder 15 is a material having good sliding property and excellent wear resistance, such as Delrin (registered trademark). It is preferable to form by
As described above, in this embodiment, the sealing mechanism 14 also serving as a means for transporting the charge removal object prevents outside air from entering the front and rear chambers 6 and 7 and the main chamber 5.
The distance between the seal mechanisms 14 and 14 adjacent to each other in the conveyance direction of the sheet 1 is equal to or less than the length in the conveyance direction of the sheet 1. Therefore, the sheet 1 being moved is nipped by any one of the seal rollers 16 and 16 which also serves as the conveying means at least at one place, and is conveyed in the arrow x direction.

Next, the configuration in the main chamber 5 will be described.
In the main chamber 5, a pair of discharge electrodes 17 and 18 constituting an ion irradiation unit are provided to face each other from the upstream side in the conveyance direction of the sheet 1 indicated by the arrow x. Each of the discharge electrodes 17 and 18 is formed of a rod-like member extending along the width direction of the sheet 1 or a plurality of electrode members disposed at a predetermined interval in the width direction, and the length in the width direction of the sheet 1 Are held by electrode holders 19 and 20 made of an electrically insulating material.
The discharge electrodes 17 and 18 expose only portions facing each other, and the other portions are covered with electrode holders 19 and 20. The electrode holders 19 and 20 are an electrical insulating material covering the discharge electrode in the present invention.

Then, the facing distance of the electrode holders 19 and 20 is made to coincide with the opening 11 a of the partition wall 3 so as to be a conveyance path of the sheet 1.
Further, voltages of opposite polarities are applied to the discharge electrodes 17 and 18, respectively, and a discharge is generated therebetween to generate ions. The voltages applied to the discharge electrodes 17 and 18 may be direct current or alternating current as long as they have opposite polarities to each other, but using a direct current voltage can stabilize the discharge.

Further, in the main chamber 5, a pair of ground rollers 21 and 22 are provided in the vicinity of the downstream partition 4. The ground rollers 21 and 22 are metal rollers such as stainless steel having a length equal to the width of the sheet 1 to be neutralized, and are rotated by the roller holders 23 and 24 made of an electrically insulating material. It is held possible.
The ground rollers 21 and 22 are normally in contact with each other, but when the sheet 1 is supplied between the facing rollers, the ground rollers 21 and 22 separate and maintain the facing interval according to the thickness of the sheet 1 Is configured as. Specifically, when a light spring force in the direction in which the rotating shafts approach each other is applied to a pair of rotating shafts (not shown) of both ground rollers 21 and 22, when the sheet 1 enters between the ground rollers 21 and 22, both The ground rollers 21 and 22 are movably supported according to the thickness of the sheet 1.

Further, the outer peripheral portions of the ground rollers 21 and 22 except for their contact portions are covered with the roller holders 23 and 24. The roller holders 23 and 24 are an electrically insulating material covering the grounding roller of the present invention.
Further, between the discharge electrode holders 19 and 20 and the ground rollers 21 and 22, a guide member 25 made of an electrically insulating material and having a conveyance path 25a of the sheet 1 formed therein is provided. The sheet 1 having passed through the conveyance path 25 a is guided between the ground rollers 21 and 22.

In the static eliminator of this embodiment configured as described above, the operation of static eliminating the sheet 1 charged to a high potential by digital printing will be described. The sheet 1 is a multilayer sheet of A4 size.
The sheet 1 charged and discharged by a printing machine (not shown) is conveyed from the left side of FIG. 1 by the seal rollers 16 and 16 of the seal mechanism 14 and supplied from the opening 10a of the outer wall 8 into the front chamber 6, and the next seal It is supplied into the main chamber 5 from the opening 11 a of the partition 3 through the mechanism 14.

Since the inside of the main chamber 5 is maintained at several hundred [Pa], discharge occurs even if the potential difference between the discharge electrodes 17 and 18 is not so large, and many ions are always present between the discharge electrodes 17 and 18 It is generated. In particular, since only the portion of the discharge electrodes 17 and 18 facing the transport path of the sheet 1 is exposed, the discharge direction is concentrated, and ions can be generated on the transport path of the sheet 1.
Further, as described above, since the ground rollers 21 and 22 are also covered with the roller holders 23 and 24 other than the facing portions with the roller holders 23 and 24 made of an electrically insulating material, the ions generated by the discharge electrodes 17 and 18 are the ground roller 21, 22 can be prevented from being absorbed.
Thus, since the ions are generated on the conveyance path and the ions are not absorbed by the ground rollers 21 and 22, the sheet 1 supplied from the front chamber 6 enters the region where the ions are generated. . As a result, the surface of the sheet 1 is intensively irradiated with ions, and the surface charge is efficiently neutralized.

The sheet 1 whose surface charge has been removed in the ion irradiation step is conveyed while being guided by the guide member 25 and is moved from the front end surface toward the ground rollers 21 and 22 as shown in FIG. Discharge occurs as indicated by the arrows in.
Further, when the sheet 1 moves and is nipped by the ground rollers 21 and 22, electric discharge toward the ground rollers 21 and 22 is also generated from the end surface in the width direction of the sheet 1 as shown in FIG. The charge accumulated in the current flows to the ground side. As described above, when the sheet 1 conveyed while being discharged passes between the ground rollers 21 and 22, it is supplied from the opening 12 a of the partition 4 to the rear chamber 7 in a substantially completely discharged state. It is discharged to the outside through the opening 13 a and the sealing mechanism 14.

As described above, since the degree of vacuum in the main chamber 5 is maintained at several hundred [Pa], discharge occurs easily from the charged sheet 1, and the internal charge can be removed.
Moreover, in this embodiment, ions generated by the discharge electrodes 17 and 18 are applied to the surface of the sheet 1 on the upstream side of the discharge process including the ground rollers 21 and 22, and the charge amount of the sheet 1 is reduced. Therefore, the discharge current toward the ground rollers 21 and 22 does not become a large current as in the case where the sheet 1 having a high charge amount is suddenly pinched by the ground rollers 21 and 22 and discharged, and the sheet 1 is damaged by the discharge. There is nothing to do.
That is, if the static eliminator of this embodiment is used, perfect static elimination can be performed without damaging the sheet 1.

Further, in this embodiment, the opening 10a which is the supply port of the front chamber 6, the opening 11a which is the supply port of the main chamber 5, the electrode holders 19 and 20, the guide member 25 and the roller holders 23 and 24 are electrically insulating It is made of wood.
That is, most of the transport path of the charged sheet 1 is surrounded by electrical insulation. In other words, the grounded body such as the inner wall of the chamber body 2 that is grounded is not exposed to the sheet 1.
If the sheet 1 before charge removal approaches the grounding body, the sheet 1 may be attracted to the grounding body by the charge and stuck. For example, if the front end of the sheet 1 supplied to the front chamber 6 is stuck to the metal outer wall 8, the movement of the sheet 1 may be stopped there or the sheet may be sent in a crumpled state . Such a thing happens in the main chamber 5 as well.
However, in this embodiment, since the sheet 1 and the ground contact body are not in direct contact with each other, smooth conveyance can be realized.

There is no problem that the sheet 1 passing between the ground rollers 21 and 22 and completely removed electricity is stuck to the ground as described above, but in this embodiment, the insulating property forming the opening The members 10 to 13 and the seal mechanism 14 are made common, so that the conveyance path of the sheet 1 is surrounded by the electrically insulating material on the downstream side of the ground rollers 21 and 22 as well as on the upstream side.
However, if smooth conveyance can be realized by devising the conveyance means of the sheet 1, it is not essential to surround the conveyance path with an electrical insulating material.

  Further, since the inside of the main chamber 5 is maintained at a degree of vacuum which is very easy to discharge, if the sheet 1 comes in contact with the partition 3 or the like which is a grounded body before passing through the ion irradiation step, the sheet 1 is discharged I get damage. Therefore, the insulating member 10 provided in the partition wall 3 also functions to prevent such discharge and to maintain the order of the ion irradiation step and the discharge step.

In this embodiment, the grounding rollers 21 and 22 are used as the discharging means, but the discharging means is not limited to the grounding rollers 21 and 22.
For example, a ground electrode which does not rotate with a gap between the sheet 1 and the charged sheet 1 may be provided. However, even if the degree of vacuum is likely to be discharged, the distance to the sheet 1 needs to be as small as possible in order to complete the charge removal. Providing the ground electrode at a small distance with respect to the sheet being moved by the transport means has a problem that dimensional control is difficult.
In addition, since the frictional resistance rapidly increases under vacuum, the sheet 1 can not be moved when the non-rotating ground electrode is brought into contact. Therefore, the processing speed may be slow.
The ground rollers 21 and 22 of this embodiment are optimum in that the distance to the ground electrode can be kept at a minimum while conveying the charged sheet 1 and that the space management is not complicated.

Further, in this embodiment, as shown in FIG. 3, the lengths of the ground rollers 21 and 22 are made larger than the width of the sheet 1, but the lengths of the ground rollers 21 and 22 are greater than the width of the object to be neutralized. It may be short or long.
However, if the length of the grounding rollers 21 and 22 is equal to or longer than the width of the charge eliminating exercise, it is easier to remove the charge. This is because if the lengths of the rollers are equal or long, the distance between the end of the sheet 1 from which the internal charge is discharged and the ground roller becomes short.

Further, in this embodiment, the front chamber 6 and the rear chamber 7 are provided before and after the main chamber 5 which is a vacuum chamber provided with an ion irradiation process and a discharge process for removing electricity, so that the degree of vacuum in the main chamber 5 can be increased. I try to maintain it.
Although the seal mechanism 14 is provided at the supply port and the discharge port of each chamber, when the sheet 1 passes through the seal mechanism 14, the outside air inevitably intrudes.

In particular, when the processing speed of the sheet 1 is increased, the number of sheets 1 passing between the seal rollers 16 and 16 increases per unit time, so external air from between the seal rollers 16 and 16 easily intrudes. . However, if the front and back chambers 6 and 7 whose vacuum levels are controlled are provided before and after the main chamber 5, the influence on the main chamber 5 can be reduced even if the outside air intrudes into the front and back chambers 6 and 7. In other words, by providing the front and back chambers 6, 7, the processing speed of the static elimination can also be increased.
In addition, the front and back chambers 6 and 7 are not limited to one before and after the main chamber 5. A plurality of front chambers and rear chambers may be provided to increase the degree of vacuum toward the main chamber 5 in stages.

For example, as shown in FIG. 1, the back and forth chambers 6, 7 are provided, and the degree of vacuum in the main chamber 5 is maintained at about 500 [Pa] and the inside of the front and back chambers 6, 7 is about 2000 [Pa]. The throughput was 60 per minute. On the other hand, when the sealing mechanism 14 adjacent to the outer walls 8 and 9 was omitted and the insides of the front and back chambers 6 and 7 were opened to the atmosphere, it was three sheets per minute that could be completely eliminated.
Thus, by providing the front and back chambers 6 and 7, if the degree of vacuum of the main chamber 5 is maintained, continuous processing at high speed can be enabled.
In any case, whether the front and rear chambers should be provided or not may be set according to the performance of the seal mechanism, the exhaust capacity of the vacuum pump, the target processing speed, and the like.

  It is useful when perfect charge removal is required for a sheet after digital printing.

DESCRIPTION OF SYMBOLS 1 (Electrostatic discharge object) sheet 2 chamber main body 5 main chamber 6 front chamber 7 back chamber 10a-13a opening (supply port, discharge port)
14 Seal mechanism (also serves as transport means)
Reference Signs List 15 holder 16 seal roller 16a rotary shaft 16b elastic member 17, 18 discharge electrode 10, 20 electrode holder 21, 22 ground roller 23, 24 roller holder 25 guide member P1, P2 vacuum pump

Claims (11)

In the vacuum chamber
An ion irradiation step of irradiating ions;
A discharging method comprising: discharging the ions from the discharging means and bringing the charge of the object to be discharged into contact with or close to the ground via the discharging means by bringing the discharging means into contact with or close to the discharging object. With a vacuum chamber,
Transport means for transporting the object of static elimination in the vacuum chamber;
Ion irradiation means for irradiating the ions to the object to be neutralized;
A discharge means provided downstream of the ion irradiation means in the transport direction of the object to be neutralized;
A static eliminator wherein the charge of the static charge object is caused to flow to the ground side by bringing the discharge means into contact with or close to the static charge object.   3. The static eliminator according to claim 2, wherein the discharge means comprises a ground electrode in contact with or close to the static charge object in the transport path of the static charge object. The ground electrode constituting the discharge means comprises a pair of ground rollers sandwiching the object to be neutralized.
4. The static eliminator according to claim 3, wherein the charge is made to flow from the object of static elimination passing between the pair of ground rollers to the ground side.   5. The static eliminator according to claim 4, wherein the pair of ground rollers have a length equal to or greater than the width of the static charge object. The pair of contact rollers are
The static elimination device according to claim 4, wherein an outer peripheral portion excluding a portion in contact with the transport path of the static elimination target is covered with an electrically insulating material. The ion irradiation unit is a pair of discharge electrodes disposed opposite to each other across the transport path of the object to be neutralized, to which a voltage of reverse polarity is applied.
The charge removing device according to any one of claims 2 to 5, wherein the pair of discharge electrodes is covered with an electrically insulating material except for the portions facing each other. The above vacuum chamber
A supply port for supplying the object to be neutralized;
An outlet for discharging the object to be neutralized;
Transport means for transporting the object of static elimination from the supply port to the discharge port;
The charge removal apparatus according to any one of claims 2 to 7, wherein the supply port and the discharge port are provided with a seal mechanism which enables movement of the charge removal target while preventing the entry of external air. The above vacuum chamber is the main chamber,
At least one sub-chamber is disposed in series upstream and downstream of the main chamber with respect to the transport direction of the object to be neutralized, respectively.
A transfer means is provided for transferring the object of charge removal from the most upstream sub-chamber to the most downstream sub-chamber;
Each sub-chamber
As vacuum implementation means are connected,
The supply port and the discharge port of the above-mentioned charge removal object are provided,
The charge removal apparatus according to any one of claims 2 to 8, wherein the supply port and the discharge port are provided with a seal mechanism which enables the movement of the charge removal target while preventing the entry of the outside air. The seal mechanism provided at the supply port and the discharge port of the main chamber and the sub chamber comprises a pair of seal rollers at least the surface of which is formed of an elastic member,
The static elimination device according to claim 8 or 9, wherein a rotational drive mechanism is connected to each of the seal rollers. In the vacuum chamber,
The static elimination apparatus according to any one of claims 2 to 10, further comprising a guide member formed of an electrically insulating material, along the transport path of the static elimination target.

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