JP7738495B2 - Corona discharge treatment device, corona discharge treatment method, film manufacturing system, and film manufacturing method - Google Patents

Description

The present invention relates to a corona discharge treatment device, a corona discharge treatment method, a film production system, and a film production method.

There is a technology for treating the surface of a film by subjecting it to a corona discharge treatment (see, for example, Patent Document 1). Furthermore, Patent Document 2 describes a test device and test method for evaluating surface treatment devices that utilize corona discharge.

Japanese Patent Application Laid-Open No. 2017-197766 Japanese Patent Application Laid-Open No. 2021-135173

In corona discharge treatment devices that use corona discharge for surface treatment, corona discharges are repeatedly generated between a roll and an electrode that are positioned opposite each other across the surface treatment target, such as a film. However, the inventors' research has revealed that repeated corona discharges can cause electrolytic corrosion in the bearings that support the shafts that are integrally formed with the rolls.

Due to the above circumstances, there is a need for technology to suppress electrolytic corrosion of bearings that support shafts formed integrally with rolls in corona discharge treatment devices.

One embodiment of the corona discharge treatment device disclosed in this application is a corona discharge treatment device that performs surface treatment on an object to be treated by generating a corona discharge on the surface of the object, and includes: a conductive roll that is rotatable about a first axis; a conductive shaft that is formed integrally with the roll and is rotatable about the first axis; a bearing that supports the shaft in a rotatable state; an electrode that is positioned opposite the roll and spaced apart from the roll; a high-frequency power supply that is connected to the electrode and generates a corona discharge between the electrode and the roll; and an AC/DC converter that converts an alternating current (AC) based on an electric charge generated on the roll by generating a corona discharge between the electrode and the roll into a direct current.

One embodiment of the corona discharge treatment method disclosed in this application is a corona discharge treatment method in a corona discharge treatment device that performs surface treatment on a treatment object by generating a corona discharge on the surface of the treatment object. The corona discharge treatment device includes: a conductive roll that is rotatable about a first axis; a conductive shaft that is integral with the roll and rotatable about the first axis; a bearing that rotatably supports the shaft; an electrode that is positioned opposite the roll but spaced apart from the roll; and a high-frequency power supply that is connected to the electrode and generates a corona discharge between the electrode and the roll. This corona discharge treatment method converts an alternating current (AC current) based on an electric charge generated on the roll by generating a corona discharge between the electrode and the roll into a direct current (DC current) using an AC/DC converter.

One embodiment of the film production system disclosed in this application is a film production system that includes an extrusion device that kneads and extrudes raw materials into a film, a stretching device that stretches the film, a corona discharge treatment device that is one embodiment of the above that applies a surface treatment to the stretched film, and a winding device that winds up the surface-treated film.

One embodiment of the film manufacturing method disclosed in this application is a film manufacturing method that includes kneading and extruding raw materials into a film, stretching the film, applying a surface treatment to the stretched film using a corona discharge treatment device that is one embodiment of the method, and winding up the surface-treated film.

One embodiment disclosed in this application makes it possible to suppress electrolytic corrosion of bearings that support shafts formed integrally with rolls in a corona discharge treatment device.

1 is a diagram schematically illustrating a configuration of a film production system according to a first embodiment. 1 is a flowchart illustrating a film manufacturing method according to embodiment 1. 1 is a diagram showing a configuration example of a main part of a surface treatment apparatus according to a first embodiment; 1 is a diagram showing a cross section of a main part of a surface treatment device and a power storage device connected to the main part; FIG. 2 is a diagram schematically illustrating the structure of a bearing. 4 is a flowchart showing the operation of the surface treatment apparatus according to the first embodiment. 10 is a flowchart showing the operation of a surface treatment apparatus according to a modified example of the first embodiment. FIG. 10 is a diagram schematically illustrating the configuration of a surface treatment apparatus according to a second embodiment. 10 is a flowchart showing the operation of the surface treatment apparatus according to the second embodiment. FIG. 10 is a diagram schematically illustrating the configuration of a surface treatment apparatus according to a third embodiment. 10 is a flowchart showing the operation of the surface treatment apparatus according to the third embodiment. FIG. 10 is a diagram schematically illustrating the configuration of a surface treatment apparatus according to a fourth embodiment. 10 is a flowchart showing the operation of a surface treatment apparatus according to a fourth embodiment. FIG. 10 is a diagram schematically illustrating the configuration of a surface treatment apparatus according to a fifth embodiment. 10 is a flowchart showing the operation of a surface treatment apparatus according to a fifth embodiment. FIG. 10 is a diagram schematically illustrating the configuration of a surface treatment apparatus according to a sixth embodiment. 13 is a flowchart showing the operation of a surface treatment apparatus according to a sixth embodiment.

Embodiments will be described in detail below based on examples and drawings. Note that in all drawings used to explain the embodiments, components having the same functions will be assigned the same reference numerals, and repeated explanations will be omitted.

(Embodiment 1)
<Film manufacturing system>
Fig. 1 is a schematic diagram showing the configuration of a film production system according to embodiment 1. Fig. 2 is a flowchart showing a film production method according to embodiment 1.

The film production system 1 of this embodiment shown in Figure 1 includes an extrusion device 2, a T-die 3, a cooling device 4, a stretching device 5, a surface treatment device 6, a static elimination device 7, and a winding device 8. The surface treatment device 6 is an example of a corona discharge treatment device in this application. The cooling device 4 is also called a raw semi-cooling device, a cast roll, etc.

In the example shown in Figure 1, first, resin material (pellets), additives, etc. are supplied to the raw material supply section 2A of the extrusion device 2. The extrusion device 2 transports the supplied resin material while mixing it. The T-die 3 extrudes the kneaded material (molten resin) kneaded by the extrusion device 2 through a slit (S1). The kneaded material extruded from the T-die 3 is cooled in the cooling device 4 and becomes a film 9 (S2).

The raw film formed by the T-die 3 is continuously supplied to the stretching device 5 via the cooling device 4. In the stretching device 5, the film 9 is stretched, for example, in the direction in which the film 9 is discharged (hereinafter referred to as the longitudinal direction), and then stretched in the transverse direction intersecting the longitudinal direction (S3). The stretched film 9 is subjected to a surface treatment using corona discharge by the surface treatment device 6 (S4). This embodiment is characterized by the use of a power storage device in this surface treatment. This characteristic will be described later. The surface-treated film 9 is then subjected to a static elimination treatment by the static eliminator 7 to remove any charge stored on the film 9 (S5). The static eliminator-treated film 9 is then taken up by the winding device 8 (S6).

In the case of the film production system 1 shown as an example in Figure 1, the film 9 is produced as described above. The film production system 1 shown in Figure 1 can be modified in various ways depending on the characteristics of the film 9 to be formed. For example, in the example shown in Figure 1, the film 9 is stretched in the longitudinal direction and then stretched in the transverse direction. However, the method of stretching the film 9 is not particularly limited, and for example, it may be configured to stretch the film 9 in both the longitudinal and transverse directions simultaneously.

Furthermore, film 9 can also be referred to as a film sheet, meaning a film stretched into a sheet. In this embodiment, the object to be treated with corona discharge treatment is a film, but this film includes films made from various materials, including plastics such as polyethylene. Here, plastic refers to thermoplastic resins, thermosetting resins, photocurable resins, etc. Furthermore, the object to be treated is not limited to film, and can also be other sheet-like objects such as paper, cloth including nonwoven fabric, metal foil, etc.

The cooling device 4 and cooling process (S2) may be omitted depending on the type or material of the film. The static eliminator 7 and static elimination process (S5) may also be omitted depending on the type or material of the film.

<Surface treatment equipment>
Fig. 3 is a diagram showing an example of the configuration of the main parts of the surface treatment device according to embodiment 1. Fig. 4 is a diagram showing a cross section of the main parts of the surface treatment device and a power storage device connected to the main parts. The cross section of the main parts of the surface treatment device shown in Fig. 4 is a cross section showing the main parts as viewed along the film traveling direction.

The surface treatment device 6 modifies the surface condition of the film 9 by generating a corona discharge on the surface of the film 9. When a corona discharge is generated on the surface of the film 9, the surface roughness of the film 9 increases and polar groups such as carboxyl groups and hydroxyl groups are introduced, resulting in surface modification. As a result, the "wettability" of the film 9 can be improved. Improving the wettability of the surface of the film 9 can improve the printing characteristics or adhesive properties of the film 9.

The surface treatment device 6 has a roll 61 that transports the film 9 and an electrode 62 that is positioned opposite the roll 61 across the film 9. As shown in FIG. 4, the roll 61 rotates around an axis 61R (first axis). The roll 61 is also formed integrally with a shaft 65 that rotates around the axis 61R. The shaft 65 is supported by a bearing 66.

Figure 5 is a schematic diagram showing the structure of a bearing. As shown in Figure 5, bearing 66 has balls 67, which are rolling elements made of a conductive material, insulating grease 68, an inner ring 691, and an outer ring 692. Inner ring 691 and outer ring 692 are raceways. Inner ring 691 is fixed to shaft 65, and outer ring 692 is fixed to casing 50, shown in Figure 4, via a housing (not shown). When shaft 65 rotates, inner ring 691 rotates in tandem with shaft 65, but balls 67, which are rolling elements, are not fixed to inner ring 691 or outer ring 692 and therefore can freely rotate within the orbit defined by inner ring 691 and outer ring 692.

In addition, insulating grease 68 is interposed between the inner ring 691 and the ball 67, and the ball 67 is insulated from the inner ring 691. In other words, insulating grease 68 is interposed between the ball 67 and the shaft 65, and the ball 67 and the shaft 65 are electrically insulated. Note that cylindrical members (rollers) (not shown) may also be used as rolling elements instead of the balls 67.

In the example shown in Figure 3, a roll 61A for the upper surface and a roll 61B for the lower surface are provided to perform surface treatment on both the upper and lower surfaces of the film 9.

In the example shown in FIG. 3, multiple electrodes 62 are disposed opposite the upper surface roll 61A and the lower surface roll 61B. Each of the multiple electrodes 62 is electrically connected to a high-frequency power supply 63. When a high-frequency voltage is applied from the high-frequency power supply 63 to each of the multiple electrodes 62, a corona discharge occurs between each of the multiple electrodes 62 and the roll 61. In the surface treatment device 6, high power is supplied from the high-frequency power supply 63 to generate a corona discharge with the film 9 interposed therebetween. For example, a high-frequency voltage with a rated output of approximately 20 kW to 70 kW and a frequency of approximately 10 kHz to 100 kHz is applied. Note that the voltages listed above are merely examples, and various variations are possible.

Furthermore, the surface treatment device 6 must continuously perform surface treatment on the film 9. In the case of the surface treatment device 6, a high-frequency power supply 63 is used as the power source for generating corona discharge, and continuous surface treatment is achieved by repeatedly generating corona discharge.

When corona discharges are repeatedly generated, if the charge generated within the roll 61 by the discharge is not discharged to the outside, the charge will accumulate within the roll 61, causing the potential difference between the electrode 62 and the roll 61 to become unstable. For this reason, the roll 61 is generally connected to a member at ground potential and is equipped with a charge eliminator 64 that removes the charge generated on the roll 61. An example of the charge eliminator 64 is a method in which a charge eliminator made of a conductive material, such as a carbon brush, is pressed against a shaft 65 formed integrally with the roll 61. This method makes it possible to stabilize the potential difference between the electrode 62 and the roll 61, allowing corona discharges to be generated repeatedly and stably.

However, the inventors' investigations have revealed that electrolytic corrosion can occur in the bearing 66 that supports the shaft 65 of the surface treatment device 6. It has been found that electrolytic corrosion of the bearing 66 can occur even when the surface treatment device 6 is operated with the charge remover 64 installed.

Further investigation by the inventors has revealed that the progression of electrolytic corrosion in bearing 66 can be slowed by at least temporarily storing the charge generated in roll 61, i.e., the AC power generated in roll 61, rather than attempting to remove the charge generated in roll 61 by dissipating it to the outside.

In this embodiment, therefore, a storage device 70 is provided that can at least temporarily store the charge generated in the roll 61.

<Electricity storage device>
4, the power storage device 70 includes a slip ring 71, a conductive member 72, a power conditioner 73, a backflow prevention unit 74, a changeover switch 75, a resistor 76, a power storage device 77, a switch 78, a first load 79, a second load 80, and a control circuit 81. The control circuit 81 is an example of the control device of the present application.

The slip ring 71 is attached to the shaft 65 so as to be electrically conductive with the shaft 65.

The conductive member 72 is supported so as to contact the slip conductive surface of the slip ring 71. The conductive member 72 may be, for example, a carbon brush or an air gap. The slip conductive surface of the slip ring 71 is generally made of a material such as carbon, but it is more preferable to use carbon impregnated with a highly conductive material such as silver or copper.

Power conditioner 73 converts the input AC current into DC current and outputs it by increasing or decreasing the voltage as necessary. Power conditioner 73 has two input terminals: one input terminal is connected to conductive member 72, and the other input terminal is grounded or connected to a member at ground potential. With this connection configuration, AC current based on randomly generated charges on roll 61 passes through shaft 65, slip ring 71, and conductive member 72, is input to power conditioner 73, and is converted to DC current. Note that power based on this AC current can have, for example, a voltage (effective value) of approximately 0.5 V to 5 V and an average frequency of approximately 10 kHz to 100 kHz.

When converting AC current to DC current, the power conditioner 73 operates to temporarily store the input charge, i.e., the charge generated in the roll 61. This operation of temporarily storing the charge generated in the roll 61 allows the charge generated in the roll 61 to be quickly absorbed, reducing the amplitude of the AC current or AC voltage generated in the roll 61. As a result, the momentum of the charge passing through the bearing 66 is reduced, which is thought to slow the progression of electrolytic corrosion in the bearing 66. Note that "temporarily storing charge" here means that charge is temporarily taken in and absorbed by a smoothing capacitor or the like during the process of converting AC current to DC current. Therefore, "temporarily storing charge" does not limit the amount of time the charge is stored.

The power conditioner 73 includes, for example, an AC/DC converter and a step-up/step-down circuit. The AC/DC converter is configured to have, for example, a rectifier circuit such as a diode bridge and a smoothing capacitor. The power conditioner 73 may be a discrete circuit constructed using semiconductor elements, passive elements, etc., or a circuit constructed using a dedicated IC.

The backflow prevention unit 74 has its input terminal connected to the output terminal of the power conditioner 73. The backflow prevention unit 74 serves to prevent current from flowing back into the power conditioner 73 and damaging the power conditioner 73. The backflow prevention unit 74 is, for example, a diode.

The changeover switch 75 has one input terminal T0, a changeover terminal S connected to the input terminal T0, and two output terminals, the first output terminal T1 and the second output terminal T2, which are selectively connected to the changeover terminal S. That is, the changeover switch 75 is configured to be able to either have its changeover terminal S connected to the first output terminal T1, or have its changeover terminal S connected to the second output terminal T2. The input terminal T0 of the changeover switch 75 is connected to the output terminal of the backflow prevention unit 74. The changeover switch 75 is, for example, a relay switch or a semiconductor switch such as a MOSFET.

A circuit consisting of a resistor 76, a capacitor 77, a switch 78, and a first load 79 connected in series is connected to the first output terminal T1 of the changeover switch 75. A second load 80 is connected to the second output terminal T2 of the changeover switch 75. The output terminals of the first load 79 and the second load 80 are each grounded or connected to a component at ground potential.

Resistor 76 is an element that converts input power into heat and consumes it. Resistor 76 serves to prevent inrush current from flowing to capacitor 77.

The capacitor 77 stores power based on the DC current output from the power conditioner 73. The capacitor 77 is configured to include, for example, a capacitor or a secondary battery such as a nickel-metal hydride battery or a lithium-ion battery. The capacitor 77 may also include a control circuit that controls charging or power supply. The capacitor 77 is configured to be detachable, and a charged capacitor 77 can be removed and used as a power source for an external device. Note that there are two types of capacitors 77: one that can supply power while being charged, and one that cannot supply power while being charged. This embodiment can accommodate both types of capacitors, but in this example, the capacitor 77 is assumed to be a type that cannot supply power while being charged.

Switch 78 is a switch used to switch whether or not the capacitor 77 and the first load 79 are connected. When switch 78 is closed, the capacitor 77 is connected to the first load 79, and the power stored in the capacitor 77 is supplied to the first load 79. On the other hand, when switch 78 is opened, the connection between the capacitor 77 and the first load 79 is cut off. Switch 78 is composed of, for example, a transistor, MOSFET, relay switch, etc.

The first load 79 is, for example, an electronic circuit that operates when supplied with power. This electronic circuit may be a circuit that constitutes the surface treatment device 6 or a circuit that constitutes the film production system 1, or it may be a circuit that constitutes another device or system, or a circuit that operates independently.

If the capacitor 77 is of a type that cannot supply power while it is being charged, the first load 79 is normally supplied with power from a main power source (not shown) and uses the capacitor 77 as a secondary power source only when power is stored in the capacitor 77. On the other hand, if the capacitor 77 is of a type that can supply power even while it is being charged, the first load 79 uses the capacitor 77 as a power source.

In this embodiment, the first load 79 is assumed to be an electronic circuit, but it may also be, for example, something that converts electricity into heat, light, or power. In this case, the first load 79 may be, for example, a resistor, a light-emitting element, or a motor.

The second load 80 is, for example, a device that converts electricity into heat, light, or motive power. In this case, the second load 80 is, for example, a resistor, a light-emitting element, a motor, etc.

In the initial state, the input terminal and the first output terminal of the selector switch 75 are connected, and the switch 78 is open. This means that the power generated by the charge on the roll 61 is temporarily stored in the power conditioner 73 and then charged into the capacitor 77 via the backflow prevention unit 74, the selector switch 75, and the resistor 76.

The control circuit 81 has the function of detecting the state of the capacitor 77. Based on the detection result of the state of the capacitor 77, the control circuit 81 controls the switching of the selector switch 75 and the opening and closing of the switch 78.

The control circuit 81 continuously or periodically detects the charging current and charging voltage (amount of stored electricity) of the capacitor 77. When the control circuit 81 detects that the detected charging voltage of the capacitor 77 has risen to a set upper voltage V1 (first level), it switches the connection destination of the switching terminal S of the changeover switch 75 to the second output terminal T2, i.e., the second load 80 side, and controls the switch 78 to close. The upper voltage V1 is, for example, the voltage corresponding to a fully charged capacitor 77, or the upper limit voltage that can be supplied by the first load 79 if the first load 79 is a circuit.

This control electrically connects the capacitor 77 and the first load 79, causing the capacitor 77 to supply power to the first load 79. While the capacitor 77 is supplying power to the first load 79, power based on the charge generated in the roll 61 is supplied to the second load 80 via the power conditioner 73, backflow prevention unit 74, and selector switch 75.

When the control circuit 81 detects that the detected charging voltage (amount of stored electricity) of the capacitor 77 has dropped to the set lower voltage V2 (second level), it switches the connection of the switching terminal S of the changeover switch 75 to the first output terminal T1, i.e., the capacitor 77 side, and controls the switch 78 to open. The lower voltage V2 is, for example, a voltage corresponding to the lower discharge limit of the capacitor 77, or the lower limit voltage that the first load 79 can supply if it is a circuit. This control electrically disconnects the capacitor 77 from the first load 79, and the capacitor 77 is charged.

The control circuit 81 has the function of detecting abnormalities in the capacitor 77. The control circuit 81 detects an abnormality when the detected charging current or charging voltage of the capacitor 77 exceeds a set upper limit level. That is, the control circuit 81 detects an overvoltage or overcurrent of the capacitor 77 as an abnormality. When the control circuit 81 detects an abnormality in the capacitor 77, it switches the switching terminal S of the changeover switch 75 to the second output terminal T2, i.e., the second load 80 side, stopping charging of the capacitor 77 and preventing damage to the capacitor 77. Furthermore, when the control circuit 81 detects an abnormality in the capacitor 77, it opens the switch 78 to disconnect the capacitor 77 from the first load 79 and prevent damage to the first load 79.

The control circuit 81 is composed of, for example, a circuit using a dedicated IC, a PLC, a microcomputer, etc.

<Operation of Surface Treatment Device>
The operation of the surface treatment device 6 will now be described.

Figure 6 is a flowchart showing the operation of the surface treatment device according to embodiment 1. As shown in Figure 6, first, corona discharge is initiated (S11). Specifically, while the drive source rotates the roll 61 to transport the film 9, the high-frequency power supply 63 repeatedly generates corona discharge between the roll 61 and the electrode 62.

Next, the power conditioner 73 temporarily stores the AC current generated by the charge on the roll 61 and converts it to DC current (S12). At this point, the selector switch 75 and switch 78 are in their initial states. That is, the selector terminal S of the selector switch 75 is connected to the first output terminal T1, and the switch 78 is open. Therefore, the DC current output from the power conditioner 73 is stored in the capacitor 77.

Next, the control circuit 81 detects the state of the capacitor 77 and determines whether or not an abnormality exists based on the detection results (S13). If the control circuit 81 determines that an abnormality exists (S13: Yes), it switches the connection destination of the switching terminal S of the changeover switch 75 to the second output terminal T2, i.e., the second load 80 side, and stops charging of the capacitor 77 (S14). Furthermore, the control circuit 81 opens the switch 78 to disconnect the capacitor 77 from the first load 79, protecting the first load 79 (S15), and ends the process.

On the other hand, if the control circuit 81 determines that there is no abnormality (S13: No), it determines whether the charging voltage V of the capacitor 77 has reached voltage V1, which corresponds to full charge (S16). If the control circuit 81 determines that the charging voltage V has reached voltage V1 (S16: Yes), it switches the connection destination of the switching terminal S of the changeover switch 75 to the second output terminal T2, i.e., the second load 80 side, and stops charging of the capacitor 77 (S17). Furthermore, the control circuit 81 closes switch 78 to connect the capacitor 77 to the first load 79, and the capacitor 77 begins supplying power to the first load 79 (S18). Then, it proceeds to step S19.

On the other hand, if the control circuit 81 determines that the charging voltage V of the capacitor 77 has not reached voltage V1 (S16: No), the process proceeds to step S19, where it determines whether the charging voltage V of the capacitor 77 has dropped to voltage V2, which corresponds to insufficient charging (S19). If the control circuit 81 determines that the charging voltage V has dropped to voltage V2 (S19: Yes), it opens switch 78 to disconnect the capacitor 77 from the first load 79 (S20). Furthermore, the control circuit 81 switches the connection destination of the switching terminal S of the changeover switch 75 to the first output terminal T1, i.e., the capacitor 77 side, and begins charging the capacitor 77 (S21). Then, the process proceeds to step S22.

If the control circuit 81 determines in step S19 that the charging voltage V of the capacitor 77 has not dropped to voltage V2 (S19: No), the control circuit 81 proceeds to step S22, where it continues charging the capacitor 77 (S22). Then, the control circuit 81 proceeds to step S23.

In step S23, the control circuit 81 determines whether the processing should be terminated based on a user operation or the occurrence of an event that requires termination (S23). If the control circuit 81 determines that the processing should be terminated (S23: Yes), it terminates the processing. If the control circuit 81 determines that the processing should not be terminated (S23: No), it returns to step S13 and continues processing.

According to the above-described first embodiment, the electric charge generated in the roll 61 is temporarily stored in the power conditioner 73, thereby suppressing electrolytic corrosion of the bearing 66, i.e., slowing the progression of electrolytic corrosion. Furthermore, the direct current output from the power conditioner 73 is charged to the capacitor 77. The charged capacitor 77 can be used as a power source for the first load 79 or an external device. This function allows the electric charge generated in the roll 61, which would otherwise be unnecessary, to be used as a power source, contributing to energy savings.

This embodiment is an example in which a surface treatment device using corona discharge is applied to a film production system that produces plastic film. However, it can also be applied to film production systems that produce materials other than plastic film. For example, surface treatment using corona discharge may also be performed in the process of producing paper, fabrics including nonwoven fabrics, metal foil, etc. Therefore, the surface treatment device disclosed herein can similarly be applied to film production systems that produce such paper, fabrics, metal foil, etc.

<Variation 1>
In the above embodiment, the capacitor 77 is of a type that cannot supply power while being charged. In this modified example, the capacitor 77 is of a type that can supply power while being charged. In this case, it is not necessary to stop charging the capacitor 77 even when the capacitor 77 is fully charged or insufficiently charged.

Figure 7 is a flowchart showing the operation of a surface treatment device according to a modified example of embodiment 1. The following describes the changes from the above example. As shown in Figure 7, if it is determined that the charging voltage V of the capacitor 77 has reached voltage V1, which corresponds to a full charge (S16: Yes), the changeover switch 75 is not switched to the second load 80 side (S17). Furthermore, if it is determined that the charging voltage V of the capacitor 77 has dropped to voltage V2, which corresponds to an insufficient charge (S19: Yes), the changeover switch 75 is not switched to the capacitor 77 side (S21).

In this variant 1, the capacitor 77 is of a type that can supply power while being charged, so there is no need to stop charging the capacitor 77 even if the capacitor 77 is fully charged or insufficiently charged.

<Variation 2>
In the above embodiment, insulating grease 68 is interposed between the ball 67 inserted in the bearing 66 and the shaft 65. In this modified example, the insulating grease 68 is changed to conductive grease. This configuration intentionally brings the bearing 66 closer to the potential of the roll 61, preventing electrical shock to the bearing 66 that would be expected to occur if the insulating grease were to break down.

In this variant, conductive grease is used between the ball 67 inserted in the bearing 66 and the shaft 65, preventing electrical shock to the bearing 66 that would otherwise occur if the grease were to break down.

In addition, the inventor's research has revealed that if insulating grease 68 is interposed between the ball 67 inserted in the bearing 66 and the shaft 65, the amount of power input to the power conditioner 73 may be relatively high. In order to simultaneously suppress electrolytic corrosion of the bearing 66 and save energy by supplying power to the capacitor 77, first load 79, or second load 80, it may be better to interpose insulating grease 68 between the ball 67 and the shaft 65.

(Embodiment 2)
A surface treatment apparatus according to a second embodiment will be described.

Figure 8 is a diagram schematically illustrating the configuration of a surface treatment device according to embodiment 2. As shown in Figure 8, the surface treatment device 6a according to embodiment 2 differs from embodiment 1 in the configuration of the power storage device. In the surface treatment device 6a, the power storage device 70a is configured so that a second load is not connected, and power from the power conditioner 73 is used to charge the capacitor 77 and supply power to the first load 79.

As shown in FIG. 8, the power storage device 70a has a configuration in which the selector switch 75, switch 78, second load 80, and control circuit 81 are omitted compared to embodiment 1. That is, a backflow prevention unit 74, resistor 76, power storage device 77, and first load 79 are connected in series to the output terminal of the power conditioner 73. Furthermore, the power storage device 77 is a type that can supply power while being charged.

Figure 9 is a flowchart showing the operation of the surface treatment device according to embodiment 2. As shown in Figure 9, first, the high-frequency power supply 63 initiates corona discharge (S41). Next, the power conditioner 73 temporarily stores the charge generated on the roll 61 and converts the AC current based on that charge into DC current (S42). The capacitor 77 is charged by the DC current (S43). The capacitor 77 supplies power to the first load 79 (S44).

With the surface treatment device 6a according to this second embodiment, as with the first embodiment, the charge generated in the roll 61 can be temporarily stored in the power conditioner 73, thereby suppressing electrolytic corrosion of the bearing 66. Furthermore, with the surface treatment device 6a according to the second embodiment, the control circuit 81 is not required, which simplifies the configuration and reduces the risk of failure and costs. Furthermore, if the first load 79 is an electronic circuit, the charge generated in the roll 61 can be used as power to supply to the electronic circuit, contributing to energy savings.

(Embodiment 3)
A surface treatment apparatus according to a third embodiment will be described.

Figure 10 is a diagram schematically illustrating the configuration of a surface treatment device according to embodiment 3. As shown in Figure 10, the surface treatment device 6b according to embodiment 3 differs from embodiment 1 in the configuration of the power storage device. In the surface treatment device 6b, the power storage device 70b is configured so that no load is connected, and power from the power conditioner is used to charge the capacitor 77.

As shown in FIG. 10, the power storage device 70b has a configuration in which the selector switch 75, switch 78, first load 79, second load 80, and control circuit 81 are omitted compared to embodiment 1. That is, a backflow prevention unit 74, resistor 76, and power storage device 77 are connected in series to the output terminal of the power conditioner 73. The power storage device 77 is configured to be detachable.

Figure 11 is a flowchart showing the operation of the surface treatment device according to embodiment 3. As shown in Figure 11, first, the high-frequency power supply 63 initiates corona discharge (S51). Next, the power conditioner 73 temporarily stores the charge generated on the roll 61 and converts the AC current based on that charge into DC current (S52). The capacitor 77 is charged by that DC current (S53).

With the surface treatment device 6b according to embodiment 3, as with embodiment 1, the charge generated in the roll 61 is temporarily stored in the power conditioner 73, thereby suppressing electrolytic corrosion of the bearing 66. Furthermore, with the surface treatment device 6a according to embodiment 3, the control circuit 81 is not required, which simplifies the configuration and reduces the risk of failure and costs. Furthermore, the charge generated in the roll 61 can be stored in a capacitor 77, which can be used as a power source for other circuits, etc. Furthermore, if the capacitor 77 has a large storage capacity, it is possible to eliminate the need for complicated work such as replacing the capacitor when it becomes fully charged.

(Embodiment 4)
A surface treatment apparatus according to a fourth embodiment will be described.

Figure 12 is a diagram schematically illustrating the configuration of a surface treatment device according to embodiment 4. As shown in Figure 12, the surface treatment device 6c according to embodiment 4 differs from embodiment 1 in the configuration of the power storage device. The surface treatment device 6c is configured so that the power storage device 70c can sequentially charge multiple capacitors.

As shown in FIG. 12, compared to embodiment 1, power storage device 70c has a changeover switch 75a instead of changeover switch 75. Furthermore, power storage device 70c has a resistor 76a and a first capacitor 77a, and a resistor 76b and a second capacitor 77b instead of resistor 76 and capacitor 77. Switch 78 and first load 79 are omitted.

As shown in FIG. 12, a backflow prevention unit 74 is connected to the output terminal of the power conditioner 73, and the input terminal T0 of the selector switch 75a is connected to the output terminal of the backflow prevention unit 74. The selector switch 75a has three output terminals.

A resistor 76a and a first capacitor 77a are connected in series to the first output terminal T1. A resistor 76b and a second capacitor 77b are connected in series to the third output terminal T3. A second load 80 is connected to the second output terminal T2. The first capacitor 77a and the second capacitor 77b are configured to be detachable. A control circuit 81 detects the states of the first capacitor 77a and the second capacitor 77b and controls the selector switch 75a based on the detection results.

Figure 13 is a flowchart showing the operation of the surface treatment device according to embodiment 4. As shown in Figure 13, first, the high-frequency power supply 63 initiates corona discharge (S61). Next, the power conditioner 73 temporarily stores AC current based on the charge generated on the roll 61 and converts it to DC current (S62). The control circuit 81 first switches the connection destination of the switching terminal S of the changeover switch 75 to the first output terminal T1, i.e., the first capacitor 77a (S63). The power output from the power conditioner 73 is configured to be stored in the first capacitor 77a.

Next, the control circuit 81 detects the state of the first capacitor 77a and determines whether or not an abnormality exists based on the detection result (S64). If the control circuit 81 determines that an abnormality exists (S64: Yes), it switches the connection destination of the switching terminal S of the changeover switch 75 to the second output terminal T2, i.e., the second load 80 side, stops charging the first capacitor 77a (S65), and ends the process.

On the other hand, if the control circuit 81 determines that there is no abnormality (S64: No), it determines whether the charging voltage Va of the first capacitor 77a has reached voltage V1, which corresponds to full charge (S66). If the control circuit 81 determines that the charging voltage Va has not reached voltage V1 (S66: No), it continues charging the first capacitor 77a (S67). Then, the control circuit 81 determines whether the processing should be terminated based on a user operation or the occurrence of an event that requires termination (S68). If the control circuit 81 determines that the processing should be terminated (S68: Yes), it terminates the processing. If the control circuit 81 determines that the processing should not be terminated (S68: No), it returns to step S64 and continues processing.

In step S66, if the control circuit 81 determines that the charging voltage Va has reached voltage V1 (S66: Yes), it switches the connection destination of the switching terminal S of the changeover switch 75 to the third output terminal T3, i.e., the second capacitor 77b side, and starts charging the second capacitor 77b (S69). At this time, the fully charged first capacitor 77a is replaced by the user with another uncharged capacitor.

Furthermore, the control circuit 81 detects the state of the second capacitor 77b and determines whether or not an abnormality has occurred based on the detection result (S70). If the control circuit 81 determines that an abnormality has occurred (S70: Yes), it proceeds to step S65, switches the connection destination of the switching terminal S of the changeover switch 75 to the second output terminal T2, i.e., the second load 80 side, stops charging the second capacitor 77b (S65), and ends the process.

On the other hand, if the control circuit 81 determines in step S70 that there is no abnormality (S70: No), it determines whether the charging voltage Vb of the second capacitor 77b has reached voltage V1, which corresponds to full charge (S71). If the control circuit 81 determines in step S71 that the charging voltage Vb has reached voltage V1 (S71: Yes), it returns to step S63, switches the connection destination of the switching terminal S of the changeover switch 75 to the first output terminal T1, i.e., the first capacitor 77a side, and resumes charging of the uncharged first capacitor 77a (S63). At this time, the fully charged second capacitor 77b is replaced by another uncharged capacitor by the user.

In step S71, if the control circuit 81 determines that the charging voltage Vb has not reached voltage V1 (S71: No), it continues charging the second capacitor 77b. The control circuit 81 then determines whether or not to terminate the process based on a user operation or the occurrence of an event that requires termination (S73). If the control circuit 81 determines that the process should be terminated (S73: Yes), it terminates the process. If the control circuit 81 determines that the process should not be terminated (S73: No), it returns to step S70 and continues the process.

With the surface treatment device 6c according to embodiment 4, as with embodiment 1, the charge generated in the roll 61 can be temporarily stored in the power conditioner 73, thereby suppressing electrolytic corrosion of the bearing 66. Furthermore, with the surface treatment device 6a according to embodiment 4, the charge generated in the roll 61 can be efficiently stored in multiple capacitors, contributing to energy savings.

(Embodiment 5)
A surface treatment apparatus according to a fifth embodiment will be described.

Figure 14 is a diagram schematically illustrating the configuration of a surface treatment device according to embodiment 5. As shown in Figure 14, the surface treatment device 6d according to embodiment 5 differs from embodiment 1 in the configuration of the power storage device. The surface treatment device 6d does not include a capacitor in its power storage device 70d, and is configured so that power from a power conditioner 73 that temporarily stores the charge generated in the roll 61 is supplied to a first load 79 composed of an electronic circuit or the like.

As shown in FIG. 14, the power storage device 70d has a configuration in which the selector switch 75, resistor 76, power storage device 77, switch 78, second load 80, and control circuit 81 are omitted compared to embodiment 1. That is, a backflow prevention unit 74 and a first load 79 are connected in series to the output terminal of the power conditioner 73. The first load 79 is, for example, an electronic circuit, such as a circuit constituting the surface treatment device 6d or the film production system 1, or an external device. The first load 79 may use the power conditioner 73 as the main power source, or may have a separate main power source and use the power conditioner 73 as a secondary power source.

Figure 15 is a flowchart showing the operation of the surface treatment device according to embodiment 5. As shown in Figure 15, first, the high-frequency power supply 63 initiates corona discharge (S81). Next, the power conditioner 73 temporarily stores the charge generated on the roll 61 and converts the AC current based on that charge into DC current (S82). The first load 79 receives power from that DC current (S83).

With the surface treatment device 6d according to this fifth embodiment, as with the first embodiment, the charge generated in the roll 61 is temporarily stored in the power conditioner 73, thereby suppressing electrolytic corrosion of the bearing 66. Furthermore, with the surface treatment device 6a according to the fifth embodiment, a control circuit and a capacitor are not required, which simplifies the configuration and reduces the risk of breakdowns and costs. Furthermore, if the first load 79 is an electronic circuit, the charge generated in the roll 61 can be used as power to supply to the electronic circuit, contributing to energy savings.

(Embodiment 6)
A surface treatment device according to a sixth embodiment will be described.

Figure 16 is a diagram schematically illustrating the configuration of a surface treatment device according to embodiment 6. As shown in Figure 16, the surface treatment device 6e according to embodiment 6 differs from embodiment 1 in the configuration of the power storage device. The surface treatment device 6e does not include a capacitor in its power storage device 70e, and is configured so that power from a power conditioner 73, which temporarily stores the charge generated in the roll 61, is supplied to a second load 80 composed of a resistor or the like.

As shown in FIG. 16, the power storage device 70e has a configuration in which the selector switch 75, resistor 76, power storage device 77, switch 78, first load 79, and control circuit 81 are omitted compared to embodiment 1. That is, a backflow prevention unit 74 and a second load 80 are connected in series to the output terminal of the power conditioner 73. The second load 80 is a passive element such as a resistor or a light-emitting element.

Figure 17 is a flowchart showing the operation of the surface treatment device according to embodiment 6. As shown in Figure 17, first, the high-frequency power supply 63 initiates corona discharge (S91). Next, the power conditioner 73 temporarily stores the charge generated in the roll 61 and converts the AC current based on that charge into DC current (S92). The second load 80 receives a supply of power based on that DC current (S83). The second load 80 converts that power into heat, light, or the like and consumes it.

With the surface treatment device 6e according to this sixth embodiment, as with the first embodiment, the charge generated in the roll 61 is temporarily stored in the power conditioner 73, thereby slowing the progression of electrolytic corrosion of the bearing 66. Furthermore, with the surface treatment device 6e according to the sixth embodiment, a control circuit is not required, which simplifies the structure and reduces the risk of failure and costs. Furthermore, if the second load 80 is a resistor, the resistor can be used as a heater. If the second load 80 is a light-emitting element, the light-emitting element can be used as lighting.

(Embodiment 7)
A surface treatment method according to a seventh embodiment will be described. The surface treatment method according to the seventh embodiment is a corona discharge treatment method in a corona discharge treatment apparatus that performs surface treatment on a treatment object by generating a corona discharge on the surface of the treatment object. The corona discharge treatment apparatus includes a conductive roll that is rotatable about a first axis, a conductive shaft that is integrally formed with the roll and is rotatable about the first axis, a bearing that rotatably supports the shaft, an electrode that is positioned opposite the roll and spaced apart from the roll, and a high-frequency power source that is connected to the electrode and generates a corona discharge between the electrode and the roll. In this surface treatment method, an electric charge generated on the roll by generating a corona discharge between the electrode and the roll is at least temporarily stored in a power conditioner including an AC/DC converter.

According to the surface treatment method of embodiment 7, the electric charge generated in the roll is temporarily stored in the power conditioner, thereby suppressing electrolytic corrosion of the bearings.

(Embodiment 8)
A film production system according to embodiment 8 will be described. The film production system according to embodiment 8 includes an extrusion device that kneads and extrudes raw materials into a film, a stretching device that stretches the film, a surface treatment device according to any one of embodiments 1 to 6 that applies a surface treatment to the stretched film, and a winding device that winds up the film that has been subjected to the surface treatment.

Note that if the raw material is metal, it may be cooled naturally and ready for stretching, but if the raw material is plastic resin, it may be necessary to cool the raw material in preparation for stretching. Therefore, the film production system may be equipped with a cooling device that cools the film extruded by the extrusion device, and the stretching device may stretch the cooled film.

Furthermore, if the raw material has physical properties that make it easy to become charged, it may be necessary to remove the charge remaining on the surface-treated film to prevent the films from sticking together and make it easier to wind. Therefore, the film production system may be equipped with a static eliminator that eliminates the charge generated on the film that has been surface-treated by the surface treatment device, and the winding device may wind up the film that has been neutralized by the static eliminator.

In the film production system according to embodiment 8, the electric charge generated in the roll is temporarily stored in a power conditioner including an AC/DC converter, thereby suppressing electrolytic corrosion of the bearings.

(Embodiment 9)
A film production method according to embodiment 9 will be described. The film production method according to embodiment 9 is a method of kneading and extruding raw materials into a film, stretching the film, subjecting the stretched film to a surface treatment using a surface treatment device according to any one of embodiments 1 to 6, and winding up the surface-treated film.

In this film manufacturing method according to embodiment 9, the electric charge generated in the roll is temporarily stored in a power conditioner including an AC/DC converter, thereby suppressing electrolytic corrosion of the bearings.

Although various embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and includes various modifications. Furthermore, the above-described embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those that include all of the configurations described. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, the numerical values, messages, etc. contained in the text and figures are merely examples, and the use of different ones does not impair the effects of the present invention.

Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations. Furthermore, the above-mentioned configurations, functions, processing units, processing means, etc. may be implemented in hardware, in part or in whole, by designing them as integrated circuits, for example. Furthermore, at least one of the above-mentioned components, functions, etc. may be implemented in software by a processor such as an MPU or CPU interpreting and executing a program that implements the respective function. Furthermore, the range of functions implemented by software is not limited, and hardware and software may be used together. Information such as programs, tables, and files that implement each function can be stored in memory, a recording device such as a hard disk or SSD, or a recording medium such as an IC card, SD card, or DVD.

1...Film manufacturing system 2...Extrusion device 3...T-die 4...Cooling device 5...Stretching device 6, 6a to 6e...Surface treatment device (corona discharge treatment device)
7... static eliminator 8... winding device 9... films 61, 61A, 61B... roll 61R... shaft (first shaft)
62, 62A, 62B...electrodes 63...high frequency power supply 64...charge remover 65...shaft 66...bearing 67...ball 68...insulating grease 70, 70a to 70e...electricity storage device 71...slip ring 72...conductive member 73...power conditioner (AC/DC converter)
74... Backflow prevention unit 75, 75a... Changeover switches 76, 76a, 76b... Resistors 77, 77a, 77b... Storage device 78... Switch 79... First load 80... Second load 81... Control circuit (control device)

Claims (19)

1. A corona discharge treatment device for treating a surface of a treatment object by generating a corona discharge on the surface of the treatment object, comprising:
a conductive roll that is rotatable about a first axis;
a shaft that is electrically conductive, is formed integrally with the roll, and is rotatable about the first axis;
a bearing that supports the shaft in a rotatable state;
an electrode disposed at a position facing the roll and spaced apart from the roll;
a high frequency power supply connected to the electrode and generating a corona discharge between the electrode and the roll;
an AC/DC converter that converts an AC current based on charges generated on the roll by generating a corona discharge between the electrode and the roll into a DC current.
Corona discharge treatment equipment. 2. The corona discharge treatment device according to claim 1,
a capacitor that stores power based on the DC current output from the AC/DC converter;
Corona discharge treatment equipment. 3. The corona discharge treatment device according to claim 2,
a load connected to the capacitor;
Corona discharge treatment equipment. 4. The corona discharge treatment device according to claim 3,
a switch interposed between the capacitor and the load;
and a control device that detects the state of the capacitor and controls opening and closing of the switch based on the detection result.
Corona discharge treatment equipment. 2. The corona discharge treatment device according to claim 1,
a changeover switch connected to an output terminal of the AC/DC converter;
a capacitor connected to a first output terminal of the changeover switch;
a switch connected to the capacitor;
a first load connected to the switch;
a second load connected to a second output terminal of the changeover switch;
Corona discharge treatment equipment. 6. The corona discharge treatment device according to claim 5,
and a control device that detects the state of the capacitor and controls the switching of the changeover switch and the opening and closing of the switch based on the detection result.
Corona discharge treatment equipment. 7. The corona discharge treatment device according to claim 6,
the first load is a circuit constituting the corona discharge treatment device;
Corona discharge treatment equipment. 7. The corona discharge treatment device according to claim 6,
the control device detects the amount of charge stored in the capacitor, and controls the switch to close when the detected amount of charge rises to an upper first level, and to open when the detected amount of charge falls to a lower second level.
Corona discharge treatment equipment. The corona discharge treatment device according to any one of claims 6 to 8,
the control device has a function of detecting an abnormality in the capacitor, and controls the changeover terminal of the changeover switch to connect to the first output terminal when no abnormality is detected, and to connect to the second output terminal when an abnormality is detected;
Corona discharge treatment equipment. The corona discharge treatment device according to any one of claims 2 to 9,
The capacitor is configured to be detachable.
Corona discharge treatment equipment. 2. The corona discharge treatment device according to claim 1,
a load that consumes power based on the DC current output from the AC/DC converter;
Corona discharge treatment equipment. The corona discharge treatment device according to claim 11,
The load is an electronic circuit.
Corona discharge treatment equipment. The corona discharge treatment device according to claim 11,
The load is a resistor or a light-emitting element.
Corona discharge treatment equipment. 2. The corona discharge treatment device according to claim 1,
An insulating grease or a conductive grease is provided between the shaft and the bearing.
Corona discharge treatment equipment. 2. The corona discharge treatment device according to claim 1,
a charge remover that releases charge generated on the roll to the outside;
Corona discharge treatment equipment. 2. The corona discharge treatment device according to claim 1,
The object to be treated is a plastic film, paper, cloth, or metal foil.
Corona discharge treatment equipment. 1. A corona discharge treatment method in a corona discharge treatment apparatus for treating a surface of an object to be treated by generating a corona discharge on the surface of the object, comprising:
The corona discharge treatment device comprises:
a conductive roll that is rotatable about a first axis;
a shaft that is electrically conductive, is formed integrally with the roll, and is rotatable about the first axis;
a bearing that supports the shaft in a rotatable state;
an electrode disposed at a position facing the roll and spaced apart from the roll;
a high-frequency power supply connected to the electrode and generating a corona discharge between the electrode and the roll,
an AC current based on charges generated on the roll by generating a corona discharge between the electrode and the roll is converted into a DC current by an AC/DC converter;
Corona discharge treatment method. An extrusion device that mixes and extrudes raw materials into film;
a stretching device for stretching the film;
The corona discharge treatment device according to any one of claims 1 to 16, which performs a surface treatment on the stretched film;
a winding device that winds up the film that has been subjected to the surface treatment. The raw materials are mixed and extruded into a film,
stretching the film;
The stretched film is subjected to a surface treatment by the corona discharge treatment device according to any one of claims 1 to 16,
winding up the surface-treated film;
Film manufacturing method.