JP2003075412A - Method and apparatus for detection of defect in film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and surely detect whether a defect exists in a multilayer film comprising a metal film layer which is generated in an injection-port molding and working operation or the like. SOLUTION: The apparatus used to detect the defect in the multilayer film 1 comprising the metal film layer is provided with a high-voltage power supply 21 and a pair of electrodes 22a, 22b which apply a voltage to the thickness direction of the multilayer film 1, an ammeter 23 which detects a current flowing when the voltage is applied by the power supply 21 and a quality judgment means 24 by which the current detected by the ammeter 23 is compared with a preset prescribed judgment reference value and by which the multilayer film 1 is judged to be containing the defect when the detected current is larger than the judgment reference value. The apparatus is constituted in such a way that the power supply 21 applies the voltage while the rise time to the multilayer film 1 is being delayed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting defects such as cracks and pinholes in a film, particularly a multilayer film having a metal film layer as an inner layer, and more particularly to delaying the rise time of an applied voltage, By determining the integral value of the charging current and the amount of voltage drop, the presence or absence of film defects can be detected and judged easily and reliably without being affected by the increase in charging current or air discharge. The present invention relates to a film defect detection method and a film defect detection device suitable for defect determination of a film to be molded.

[0002]

2. Description of the Related Art Generally, a nylon layer or PET which is a surface layer
A multilayer film in which a metal film layer made of an inner metal foil layer or a metal vapor deposition layer is formed between resin layers made of (polyethylene terephthalate) layer, PE (polyethylene) layer, etc. is excellent in light weight, flexibility and durability. Since it is easy to process and can be manufactured at low cost, it is widely used as containers and packaging materials for various products.

Recently, containers made of such a multilayer film have been used, for example, in kitchen detergents, laundry detergents, sizing agents, bleaching agents,
It has come to be used as a refill container for various liquid products such as hair wash detergent and face wash detergent. For kitchen and laundry detergents used at home etc., the container body made of plastic resin can be used semi-permanently even if the detergent inside the container is used up, so only the detergent inside can be refilled. As a container for such a refilling detergent or the like, a container made of a multi-layer film that is lightweight, has excellent durability and water resistance, and is easy to dispose of is used.

In such a multi-layered liquid container, a so-called spout molding process is performed on the surface of the container in order to improve the ease and convenience of transferring the liquid content to another container. May be given. The advantage of the multi-layered film container is that it is flexible and flexible, and the container easily bends when refilling liquid, etc., and when used as a large-capacity liquid container, it can be placed in a desired direction or location. It was also a disadvantage that it became difficult to drain the liquid. Therefore, spout molding has been developed as a means for complementing the flexibility and flexibility of such a container made of a multilayer film.

FIG. 8 is an external view of a multi-layered film container that has been subjected to this type of spout molding process. FIG. 8 (a) shows the state before bonding the containers, and FIG. 8 (b) shows the container. Shows the completed state of. As shown in FIGS. 8 (a) and 8 (b), the spout molding process is performed by pouring the liquid pouring portion 3a (see FIG. 8) of the container 3 formed by laminating and cutting the multilayer film 1.
A groove is formed in the vicinity of (upper left part of the container in (b)). In the container 3 shown in FIG. 8, two injection molding parts 2 are formed along the liquid outflow direction by a molding machine. It is designed to be bulged on the outer (front) surface side. By performing such a spout molding process, the bending of the multilayer film container is regulated and the liquid flows out along the spout molding portion, so that the refilling of the liquid can be easily and reliably performed. Therefore, it has come to be adopted as a complementing means for a container made of a multi-layered film which is rich in flexibility.

By the way, when such a spout molding process is pressure-molded on a multilayer film, a thin nylon layer or PET is formed.
When a foreign matter or the like in which the dusting agent of the film is solidified is caught in a multilayer film composed of layers, PE layers, etc., during processing, cracks or pinholes may occur. Therefore, for a multilayer film forming such a spout molding, after the spout molding processing, before the multilayer film is laminated to form a container, is there a defect such as a crack in the multilayer film? It was necessary to carry out some inspection.

As a method for detecting such cracks in the multilayer film, the present inventor first applies a high voltage in the thickness direction of the multilayer film, and detects and analyzes the current flowing at this time to detect cracks. The present invention has been devised to detect the presence or absence of such a phenomenon (hereinafter referred to as "basic invention"). This basic invention is an application of the fact that electrodes and a film form a kind of capacitor by applying a high voltage in the thickness direction of the film.

When a high voltage is applied to the multilayer film, a charging current flows through the capacitor composed of the electrode and the multilayer film. However, if the multilayer film has a defect such as a crack, the capacitor is parallel to the capacitor due to the impedance related to the size of the hole. This means that a connection circuit has been formed in the, and a kind of discharge occurs. This discharge current causes a larger current to flow when the multilayer film has a defect than when there is no defect. That is, since the current value that flows depends on the presence or absence of a defect on the multilayer film, it is possible to detect the presence or absence of a defect on the film by detecting and determining the peak value of this current. It was

[0009]

However, in the basic invention for detecting defects in a film by applying such a high voltage, accurate detection and determination of defects can be performed particularly in a multilayer film having a metal film layer. There was the problem of not having. In a multilayer film having a metal film layer such as a metal foil layer or an aluminum vapor deposition layer, since the metal film layer is formed on the entire film, the area of the metal film layer becomes large and the static electricity of the capacitor composed of the electrode and the multilayer film is reduced. The electric capacity increases and the charging current also increases. For this reason, there arises a problem that it is impossible to distinguish the charging current in a normal case from the discharging current generated by a crack or the like.

Further, in the basic invention for applying a high voltage to the film as described above, a high voltage is induced particularly when a metal layer is present in the inner layer, and the film is applied to, for example, a frame of a bag-making machine for laminating films. In the meantime, air discharge may occur. When such an air discharge occurs, even when a high voltage is applied to a normal film without defects, the detected current value becomes large, and it can be distinguished from the discharge current that flows when there are defects such as cracks. It became difficult. In this way, in the basic invention in which a high voltage is applied to compare the peak value of the current, there is a limit in detecting defects on the film,
In particular, with respect to a multi-layer film having a metal film layer, there arises a problem that accurate defect determination cannot be performed.

The present invention has been proposed in order to improve the basic invention made by the present inventor as described above and to perform accurate defect detection for all films. The rise time of the applied voltage to the film is delayed. In addition, by obtaining the integral value of the charging current and the amount of voltage drop, it is possible to easily and surely detect and determine the presence or absence of a film defect without being affected by the increase of the charging current or the air discharge. In particular, it is an object of the present invention to provide a film defect detection method and a film defect detection device suitable for defect determination of a film to which spout molding is applied.

[0012]

In order to achieve the above object, the method for detecting a defect in a film according to claim 1 of the present invention is a method for detecting a defect in a film, which comprises standing in the thickness direction of the film. This is a method of applying a voltage while delaying the raising time and determining that the film has a defect when the current flowing at this time exceeds a predetermined value.

Particularly, in the second aspect, the predetermined value is a value of a current flowing when there is no defect in the film.

According to the film defect detecting method of the present invention having such a method, the rise time to the maximum value of the high voltage applied to the film, for example, the applied voltage of 2000 V is usually raised for 50 ms. Place to raise 10
The delay is set to 0 to 150 ms, which can reduce the charging current of the film. Since the charging current when a DC voltage is applied to a capacitor is proportional to the time derivative of the voltage with the capacitance being a proportional constant (i = C · dv / dt), the voltage application means raises the applied voltage. By delaying, the charging current of the film forming the capacitor can be reduced.

As a result, the peak value of the charging current of the multilayer film having the metal film layer can be lowered, and the peak value of the charging current when there is no defect and the discharge current which occurs when there is a defect such as a crack. The difference in peak value can be increased, and the two can be clearly distinguished. Therefore,
By setting the current value of the charging current when there is no defect in the film as a reference value for determining the quality of the film, it is possible to determine that the film has a defect when a current exceeding this reference value is detected. Therefore, it is possible to easily and accurately detect a film defect caused by a spout molding process or the like.

On the other hand, the film defect detection method according to claim 3 is a method for detecting a film defect, wherein a voltage is applied in the thickness direction of the film and an integral value of the current flowing at this time is calculated. Then, when the calculated integrated value of the current exceeds a predetermined value, it is determined that the film has a defect.

In particular, the fourth aspect is a method of calculating an integral value of the current after a predetermined time has elapsed after the current flowing when a voltage was applied to the film reached the maximum value.

According to the film defect detecting apparatus of the present invention having such a method, the integrated value of the charging current and the discharging current for a certain period is calculated, and the presence or absence of a defect on the film is judged based on the integrated value. Therefore, the quality of the film can be determined by comparing the integral value of the current, not by simply comparing the peak value of the charging current. If there is no defect in the film, the charging current will be smaller after the end of charging, as with a normal capacitor, whereas the discharge current that occurs when there is a defect such as a crack on the film is
The current will flow for a longer time than the charging current in the normal case. Therefore, the integral value of the current when there is a defect in the film becomes larger than the integral value of the current when there is no defect, so by comparing this integral value with a predetermined judgment reference value, the film is The quality of can be clearly discriminated.

Thus, even when it becomes difficult to distinguish the peak value of the charging current from the peak value of the discharging current due to an increase in the charging current due to the metal film layer of the multi-layer film or an aerial or accidental air discharge. By comparing and judging the integrated value of the current, the two can be clearly distinguished,
It is possible to reliably detect defects on the film caused by the injection molding process or the like. In particular, after the charging current reaches the maximum value and the charging is completed, the integrated current value after a lapse of a certain time is calculated and determined, thereby ignoring the influence of the aerial or accidental air discharge. Therefore, the quality of the film can be determined more reliably and accurately.

On the other hand, the film defect detection method according to claim 5 is a method for detecting a film defect, wherein a voltage is applied in the thickness direction of the film, and a decrease amount of the applied voltage is calculated. This is a method of determining that the film has a defect when the calculated voltage decrease amount exceeds a predetermined value.

In particular, as a method for calculating the integrated value of the voltage drop amount and determining that the film has a defect when the integrated value of the calculated voltage drop amount exceeds a predetermined value. is there.

According to the film defect detecting apparatus of the present invention having such a method, the decrease amount of the voltage applied to the film is detected, and the decrease amount of the applied voltage or the integrated value of the decrease amount is used. It is designed to determine the presence or absence of film defects, regardless of the peak value of the charging current,
Whether the film is good or bad can be determined by whether or not the amount of voltage drop of the applied voltage exceeds a predetermined value. The voltage applied to the film rises and falls with a constant slope in the normal case where there are no defects on the film. On the other hand, if there is a defect such as a crack on the film, a large discharge current flows, the applied voltage drops, and as a result, the discharge stops and the voltage rises again and the discharge current flows. As a result, repeated discharges occur violently. Therefore, the amount of voltage drop when there is a defect in the film is larger than the amount of voltage drop when there is no defect. Therefore, by detecting and determining the amount of decrease in the applied voltage, the presence or absence of defects on the film Can be reliably detected.

As a result, by comparing and determining the amount of decrease in the applied voltage without being affected by the magnitude of the charging current or the peak value of the current due to accidental air discharge, it occurs in the spout molding process or the like. Film defects can be detected, and the quality of the film can be reliably and accurately determined. In particular, when the integrated value of the amount of decrease in the applied voltage is calculated, the integral of the amount of voltage decrease when there is a defect on the film at the time of a defect in which the voltage repeatedly rises and falls The value becomes larger than the integrated value of the voltage drop amount when there is no defect. Therefore, by calculating and determining the integrated value of this voltage drop amount, the difference between the integrated values increases depending on the presence or absence of a defect in the film, so that the two can be clearly distinguished, and a more accurate determination of the quality of the film can be made. Will be able to.

The film defect detection method according to claim 7 is a method of applying a voltage to the film while delaying the start-up time.

According to the film defect detection method of the present invention having such a method, when the high voltage is applied to the film, the start-up time to the maximum value of the applied voltage is delayed. In particular, the charging current of a multi-layer film having a metal film layer can be reduced. This allows
When the presence or absence of a defect in the film is determined based on the integrated value of the charging current, or when the determination is based on the voltage drop amount of the applied voltage, the peak value of the charging current is lowered, so that there is no defect in the film. In this case, the current value in the case can be made smaller than the current value in the case where there is a defect, so that the presence or absence of a defect on the film caused by spout molding processing can be more clearly distinguished, and a more accurate pass / fail judgment can be made. It becomes possible to do.

On the other hand, the film defect detection device according to claim 8 is a device for detecting a film defect, and a voltage application means for applying a voltage in the thickness direction of the film while delaying the rise time. , Comparing the current detected by the current detecting means for detecting a current flowing when a voltage is applied by the voltage applying means with a predetermined reference value set in advance, and detecting the detected current as a predetermined value. When it is larger than the judgment reference value, the film is judged to be defective.

According to the film defect detecting apparatus of the present invention having such a structure, by providing the film with voltage applying means for applying a high voltage, the rise time to the maximum value of the applied voltage is delayed. The film charging current can be reduced. Thereby, by using the existing voltage applying means such as a high-voltage power supply, the peak value of the charging current of the multi-layer film having the metal film layer is lowered, and the peak value of the charging current in the absence of defects and cracks, etc. Since it is possible to clearly distinguish the peak value of the discharge current that occurs when there is a defect, it is easy to determine whether there is a defect on the film caused by spout molding processing without separately providing special equipment or complicated means. Further, it is possible to provide a defect detection device that can detect and judge accurately.

A film defect detecting device according to claim 9 is a device for detecting a film defect, and a voltage applying means for applying a voltage in a thickness direction of the film,
A current detection unit that detects a current flowing when a voltage is applied by the voltage application unit, and an integrated value of the current detected by the current detection unit are calculated, and the integrated value is set to a preset predetermined reference value. And a quality determination unit that determines that the film has a defect when the integrated value is larger than the determination reference value.

According to the film defect detection apparatus of the present invention having such a structure, by providing the quality judgment means for calculating and judging the integrated value of the charging current and the discharging current in a certain period, the defect on the film can be detected. The presence / absence can be determined by comparing the integrated value of the current, not by simply comparing the peak value of the charging current. As a result, even if it is difficult to distinguish the peak values of the charging current and the discharging current due to an increase in the charging current due to the metal film layer of the film, or an aerial discharge that occurs sporadically or accidentally, existing integration current determination circuits, etc. By including the circuit etc. of, it is possible to judge the quality of the film by using the integrated value of the current, and without the need for special equipment or complicated means, defects on the film caused by spout molding processing etc. It is possible to realize a defect detection device capable of surely detecting the defect and accurately determining the quality.

On the other hand, a film defect detecting device according to a tenth aspect is a device for detecting a film defect, which comprises a voltage applying means for applying a voltage in the thickness direction of the film and the voltage applying means for applying the voltage. In addition to detecting the amount of voltage decrease, the detected amount of voltage decrease is compared with a preset predetermined reference value, and when the amount of voltage decrease is larger than the reference value, the film is defective. And a pass / fail determination means for determining.

Particularly, in the eleventh aspect, the pass / fail judgment means calculates an integrated value of the detected amount of decrease in the voltage and compares the integrated value with a predetermined judgment reference value set in advance, and the integrated value is determined. When the value is larger than the judgment reference value, it is judged that the film has a defect.

According to the film defect detecting apparatus of the present invention having such a structure, by providing the quality determining means for detecting and determining the amount of decrease in the voltage applied by the voltage applying means, it is possible to determine whether or not there is a defect on the film. It can be determined by the voltage drop amount of the applied voltage regardless of the peak value of the charging current. Therefore, by using the existing circuit such as the voltage drop judgment circuit, it is possible to detect the film defect caused by the spout molding process by comparing the applied voltage drop amount. It is possible to provide a defect detection apparatus capable of surely and accurately determining the quality of a film without being affected by the peak value of the current due to aerial air discharge.

Further, in the film defect detecting device of the twelfth aspect, the voltage applying means applies the voltage in the thickness direction of the film while delaying the rising time.

According to the film defect detecting apparatus of the present invention having such a structure, the voltage applying means for applying a high voltage to the film delays the rising time to the maximum value of the applied voltage, The charging current of the multilayer film having the metal film layer can be reduced. Thereby, even if the integrated current determination circuit that determines the integral value of the charging current to determine the presence or absence of a defect in the film, and the voltage drop determination circuit that determines the amount of voltage drop of the applied voltage, by providing the voltage applying means, The peak value of the charging current can be lowered, the presence or absence of defects on the film caused by spout molding processing can be detected more reliably without requiring special equipment or means, and a more accurate pass / fail judgment can be performed. A possible defect detecting device can be realized.

Further, in the film defect detecting device of the thirteenth aspect, at least one of the pair of electrodes provided in the voltage applying means is a conductive brush electrode.

According to the film defect detecting apparatus of the present invention having such a structure, the electrode of the voltage applying means is constituted by the conductive brush electrode having a needle-like tip,
The electric field strength at the electrode tip can be increased, and the detectability of defects such as cracks and pinholes generated on the film can be improved without increasing the applied voltage. It is suitable as an electrode when inspecting for defects such as a spout molding portion that is formed and has a height difference from other film surfaces.

[0037]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a film defect detection method and a film defect detection apparatus according to the present invention will be described below with reference to the drawings. First Embodiment First, with reference to FIGS. 1 and 2, a first embodiment of a film defect detection method and a film defect detection apparatus according to the present invention will be described. FIG. 1 is an explanatory view showing a film defect detection apparatus according to the first embodiment of the present invention, and FIG. 1A is a schematic view showing a film spout molding processing apparatus equipped with the defect detection apparatus according to the present embodiment. In plan view,
(B) is a schematic front view which shows typically the defect detection apparatus in (a). FIG. 2 is a schematic front view schematically showing the electrode portion of the defect detection device according to the present embodiment,
(A) shows the case where there is no defect in the film, and (b) shows the case where there is a defect.

First, an outline of a film spout molding apparatus equipped with the defect detection apparatus according to this embodiment will be described. The film spout molding processing apparatus according to the present embodiment is an apparatus for forming the spout molding section 2 on the multilayer film 1 by swell molding in the manufacturing process of the multilayer film container 3 shown in FIG. , As shown in FIG.
It is equipped with a spout molding machine 10, a defect detection device 20, a static eliminator 30, and a bag making machine 40. As shown in FIG. 2, the multilayer film 1 includes a nylon layer 1a serving as a surface layer, a PET layer 1b and a PE layer 1c, and a nylon layer 1a and a PET layer 1b.
And a metal film layer 1d which is an inner layer. The metal film layer 1d is formed of a metal foil layer such as aluminum or a metal vapor deposition layer.

The spout molding machine 10 is a molding means for bulging the spout molding part 2 on the multilayer film 1. As shown in FIG. 8, the spout molding portion 2 formed by the spout molding machine 10 is a groove portion formed in the multilayer film 1 forming the container 3, and the liquid is injected from the vicinity of the pouring port 3 a of the container 3. Two spout molding parts 2 are bulged and molded along the outflow direction. By forming the spout molding part 2, the bending of the multilayer film container is regulated, and the liquid serving as the content of the container is discharged along the spout molding part 2, which is highly flexible. It is designed to function as a complement to a multi-layer film container. Then, due to the injection molding process in the injection molding machine 10, defects 1e such as cracks and pinholes as shown in FIG. 2B may occur in the multilayer film 1.

The defect detection device 20 applies a high voltage to the spout molding part 2 of the multilayer film 1 formed by the spout molding machine 10 to determine whether or not defects such as cracks are generated in the multi-layer film 1. This is a device for detecting and judging, and is shown in FIG.
As shown in FIG. Details of the defect detection device 20 will be described later.

The charge removing unit 30 is a charge removing unit that removes the electric charges charged in the multilayer film 1 by the high voltage applied by the defect detection device 20. In this embodiment, the charge removing unit 30 is a conductive member that contacts the surface of the multilayer film 1. It is composed of a static elimination brush. By using such an antistatic brush, it is possible to surely eliminate the electric charges charged in the multilayer film 1. As the charge eliminating means, not only the charge eliminating brush but also a charge eliminating ribbon or a charge eliminating bar can be used.

The bag-making machine 40 has at least a sealing means and a cutting means for laminating the multilayer film 1 which has undergone the spout molding step, the defect detection step and the static elimination step, into a bag shape and cutting it into a container. There is. In this bag-making machine 40, as shown in FIG. 1, two multi-layer films 1 processed and conveyed on the upper side and the lower side, respectively, are stuck together in a bag shape, and this is formed into a predetermined shape and size. The container 3 made of a multilayer film as shown in FIG.
Will be formed. Therefore, although not shown, the spout molding machine 10 for processing and conveying the multilayer film 1, the defect detection device 20, and the static eliminator 30 are provided for the upper and lower multilayer films 1, respectively. There is.

The spout molding apparatus having the above-described structure has the same structure as that of the existing spout molding apparatus or multilayer film container forming apparatus, except that it is provided with a defect detection apparatus described later. , Has become a function. Therefore, in this embodiment, detailed description of the same components as those of the existing device will be omitted.

Next, the structure and operation of the defect detection apparatus 20 of this embodiment will be described. The defect detection device 20 is a device that detects defects (defects 1e shown in FIG. 2B) such as cracks and pinholes generated in the multilayer film 1 by performing the injection molding process, and FIG. As shown in FIG.
And an ammeter 23 and a pass / fail judgment circuit 24.

The high-voltage power supply 21 applies a high voltage to the spout molding part 2 formed in the multilayer film 1 via a pair of electrodes 22 (22a, 22b) arranged in the thickness direction of the multilayer film 1. It is supposed to do. In the present embodiment, the power source applies a high voltage of about 1000 to 10000 V, preferably 2000 to 8000 V to the spout molding unit 2. The multilayer film 1 is a surface nylon layer 1
Since a is as thin as about 15 μm, it may be destroyed if the applied voltage is too high. Therefore, in the present embodiment, the applied voltage of the high voltage power supply 21 is set to about 1000 to 10000 volts.

As shown in FIGS. 1B and 2, the pair of electrodes 22 is a conductive brush electrode 22 in which one has a high potential.
a, a metal electrode 2 in which the other has a low potential (earth potential)
2b. Specifically, the conductive brush electrode 22a has a slightly larger area than the spout molding portion 2,
The metal electrode 22b is formed in a rectangular shape having a size to cover the spout molding part 2. Since the conductive brush electrode 22a has a needle-shaped tip, the electric field strength at the tip is increased, and it is possible to improve the detectability of cracks, pinholes, etc. without increasing the applied voltage. In particular, it is suitable as an electrode of the defect detection device 20 for inspecting the spout molding portion 2 which is formed in a groove shape and has a height difference from other film surfaces.

When the electrode 22 is composed of a conductive brush, the dusting agent of the multilayer film 1 may collect in the electrode. Therefore, in order to prevent this, the applied voltage should be intermittently applied or intermittently contacted. Is preferred. Also, this electrode 2
The shape of 2 may be a conductive brush electrode or a metal electrode, and another electrode may be adopted as long as it can evenly contact the surface of the spout molding portion 2.

The ammeter 23, as shown in FIG.
The current detecting means connected in series to the high-voltage power supply 21 detects the current generated by the applied voltage of the high-voltage power supply 21. When a high voltage is applied from the high voltage power source 21 in the thickness direction of the multilayer film 1, the pair of electrodes 22
The multilayer film 1 constitutes a capacitor and a charging current flows, and the current value is detected by the ammeter 23. Here, if the multilayer film 1 has a defect such as a crack, it means that the connection circuit is formed in parallel with the capacitor due to the impedance related to the size of the hole, and the discharge current is generated. A total of 23 will be detected.

In this embodiment, the high voltage power source 21 serving as voltage applying means delays the rise time of voltage application to the multilayer film. The charging current when a DC voltage is applied to a capacitor is proportional to the time derivative of the voltage with the capacitance being a proportional constant (i = C · dv / dt). Therefore, by delaying the rise time of the voltage applied by the high-voltage power supply 21, the generated charging current can be reduced.

Up to now, in the multilayer film 1 having the metal film layer 1d made of an aluminum vapor deposition layer or the like, the capacitance is increased by the metal film layer 1d formed on the entire film, and the charging current generated by the applied voltage is increased. As a result, it cannot be distinguished from the discharge current caused by defects such as cracks, and accurate defect determination cannot be performed. Therefore, in the present embodiment, the charging current generated is reduced by delaying the rise time of the voltage applied by the high-voltage power supply 21.

Specifically, in this embodiment, the rise time to the maximum value of the applied voltage from the high voltage power source 21 is 100 to 150 ms when the applied voltage of 2000 V is normally raised to 50 ms. It is designed to be delayed. When the rise time of the applied voltage is delayed in this way, the time derivative (dv / dt) of the voltage becomes small, so that the charging current (i = C · dv) that makes the capacitance a proportional constant and the time derivative of the voltage a proportional constant. The value of / dt) can be reduced. Then, the current value detected by the ammeter 23 is input to the quality determination circuit 24, and the presence / absence of a defect in the multilayer film 1 is determined based on the detected current value.

As shown in FIG. 1B, the quality determination circuit 24 includes a setting section 24a and a comparison section 24b. The setting unit 24a is preset with a predetermined determination reference value that is compared with the current value detected by the ammeter 23, and in the present embodiment, determines the charging current value that flows when there is no defect in the multilayer film 1. It is set as a reference value. In the present embodiment, as described above, the peak value of the charging current of the multilayer film 1 can be lowered, so that the difference between the peak value of the discharging current generated when there is a defect such as a crack can be increased. , The two can be clearly distinguished. Thus, the current value of the charging current when the multilayer film 1 has no defect can be set as the determination reference value for acceptability, and it can be determined that there is a defect when a current exceeding the determination reference value is detected.

The comparing section 24b is adapted to input the current value detected by the ammeter 23 and the preset value set in the setting section 24a. It is a determining means for determining the presence or absence of. Specifically, first, when the multilayer film 1 is normal and has no defect, the rise time of the applied voltage is delayed, so that the value of the charging current becomes small and the wave of the current detected by the ammeter 23 is reduced. High price also becomes small. Since this peak value is the same value as the determination reference value set in the setting unit 24a, the comparison unit 24b determines that the multilayer film 1 has no defect.

On the other hand, when the multilayer film 1 has a defect such as a crack (see the defective portion 1d in FIG. 2B), a discharge current is generated by the applied voltage, and a large current flows momentarily, and the ammeter 23 The peak value of the electric current detected at is also larger than the peak value when there is no defect. Therefore, this crest value becomes larger than the determination reference value set in the setting unit 24a, so that the comparison unit 24b determines that the multilayer film 1 has a defect. As a result, the presence or absence of defects in the multilayer film 1 is detected, and in particular, the presence of the metal film layer 1d increases the charging current, making it impossible to distinguish from the discharge current caused by defects such as cracks. It can be resolved.

The comparison result in the comparison section 24b is as follows.
It is output as a signal and displayed externally, for example, via a display or the like not shown. Further, as a quality determination means for determining the presence / absence of a defect in the multilayer film 1 based on the peak value of the current thus detected, the quality determination is performed by manually monitoring the monitor of the ammeter 23 for detecting the current value. It is also possible to do

As described above, according to the film defect detecting method and the defect detecting apparatus of the present embodiment, the high voltage power source 21 serving as a voltage applying means for applying a high voltage to the multilayer film 1 has the maximum applied voltage. Multilayer film 1 having metal film layer 1d by delaying the start-up time to the value
The charging current can be reduced. As a result, the peak value of the charging current of the multilayer film 1 having the metal film layer 1d can be reduced, so that the peak value of the charging current when there is no defect and the discharge current that occurs when there is a defect such as a crack. The difference between the peak value and the peak value can be increased so that they can be clearly distinguished, and the presence or absence of a defect on the multilayer film 1 can be easily and accurately detected and determined. Moreover, in this embodiment, since the rising time of the applied voltage is delayed in the high voltage power source 21, the existing device can be used without requiring a special device or a complicated means separately. The quality of the multilayer film 1 can be accurately determined.

[Second Embodiment] Next, a film defect detecting method and a film defect detecting apparatus according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a schematic front view schematically showing the defect detecting device according to the second embodiment of the present invention. FIG. 4 is a graph part showing applied voltage, charge current, discharge current and integrated current values detected by the defect detecting method and apparatus according to the present embodiment. Further, FIG. 5 is a graph diagram schematically showing the relationship among the applied voltage, the charging current, the discharging current, and the integrated current value shown in FIG.

The defect detecting method and apparatus according to the present embodiment shown in these figures are modified embodiments of the above-described first embodiment, and the defect detecting apparatus in the first embodiment detects the presence or absence of a film defect. By providing an integrator, a gate pulse circuit, and an integrated current determination circuit, which are the quality determination means for determination, the quality of the film is determined by calculating and determining the integrated value of the charging current. Therefore, the other components are the same as those in the first embodiment, and the same components are designated by the same reference numerals as those in the first embodiment in the drawings, and detailed description thereof will be omitted.

As shown in FIG. 3, the defect detecting apparatus 20 of the present embodiment has an integrator 25a serving as a pass / fail judgment means 25 for judging the presence / absence of a film defect, and a gate pulse circuit 2.
5b and an integrated current determination circuit 25c. The pass / fail judgment unit 25 including the integrator 25a, the gate pulse circuit 25b, and the integrated current judgment circuit 25c calculates the integrated current value of the charging current and the discharging current based on the current value detected by the ammeter 23, and The quality of the film is judged by comparing the integrated current value with a predetermined judgment reference value. Specifically, the integrated current determination circuit 25c includes a calculation unit that calculates an integrated value of the current value input from the ammeter 23, a setting unit that sets a predetermined determination reference value, and a calculated reference value of the integrated current value. A comparison unit for comparing with the value is provided (not shown). Then, when the integrated value of the calculated current is larger than a preset predetermined determination reference value, it is determined that the film has a defect. The integrated current determination circuit 25
The determination result by c is externally displayed in a predetermined manner.

Hereinafter, the film quality judgment method using the integrated current value in the present embodiment will be described with reference to FIGS. 4 and 5 as an example in which a high voltage of 4000 V is applied to the multilayer film 1. Yes (Figs. 4 and 5
(See (a)). When a high voltage of 4000 V is applied, first, in the case where the multilayer film 1 has no defect,
As shown in, a maximum current of about 2 mA flows as the charging current, and the current value decreases in a short time after the charging is completed (see FIG. 5B). On the other hand, the multilayer film 1
When there is a defect such as a crack in the battery, a discharge occurs between the electrodes due to the crack or the like, and as shown in FIGS. 4 and 5, the maximum discharge current of about 2 mA, which is almost equal to the charging current, is normal. The current flows for a longer time than the charging current (see FIG. 5 (c)).

In this case, the peak value of the current detected by the ammeter 23 is about 2 mA both in the normal state and in the abnormal state, and it is not possible to discriminate between the peak values alone. On the other hand, the integrated current determination circuit 25c of the quality determination unit 25 is configured to calculate an integrated value of a current exceeding a predetermined threshold value for a certain period for the charging current and the discharging current detected by the ammeter 23, As shown in FIGS. 4 and 5, the calculated integrated value is larger in the abnormal state than in the normal state (see FIG. 5D). By comparing this integrated value with a predetermined judgment reference value, it is judged that the multilayer film 1 has a defect when the integrated value is larger than the judgment reference value, whereby the presence or absence of the defect 1e on the multilayer film 1 is determined. Will be detected.

By thus judging the quality of the multilayer film 1 using the integrated value of the current, the influence of the instantaneous discharge can be neglected. As described above, in the case of detecting a defect of the multilayer film 1 by applying a voltage, in addition to the discharge generated by the defect such as a crack,
The metal film layer 1d of the multilayer film 1 serves as a conductor to induce a high voltage, and an air discharge may occur between the multilayer film 1 and a frame of a bag-making machine for laminating the multilayer film 1. When such an air discharge occurs, even if a high voltage is applied to a normal part with no defect, the detected current value becomes large. It may be indistinguishable from the flowing discharge current.

Therefore, by calculating the integral value of the current flowing between the electrodes for a certain period and determining the presence / absence of a defect based on this integral value, the influence of the instantaneously flowing current can be ignored. . As a result, in the defect detection device 20 of the present embodiment, even if the charging current of the multilayer film 1 is increased, or even if a single or accidental air discharge occurs due to the high voltage application, the integrated current determination circuit. By calculating the integrated value of the current at 25c and comparing this with a predetermined judgment reference value, it becomes possible to reliably detect the defect of the multilayer film 1.

Furthermore, the integrated current judging circuit 2 of the present embodiment
In 5c, after the current detected by the ammeter 23 reaches the maximum value, the integrated value of the current after a lapse of a predetermined time is calculated, and the presence or absence of a defect in the multilayer film 1 is determined by this. As shown in FIG. 5, the time when the current reaches the maximum value is almost the same when there is no defect in the multilayer film 1 and the time when the defect is abnormal, and there is almost no difference. On the other hand, after the current reaches the maximum value, if it is normal, the current value decreases in a short time after the end of charging, whereas if there is a defect, the current continues at the maximum value for a certain period. .

Therefore, the integrated current determination circuit 2 of this embodiment
5, as shown in FIG. 5, after the charging current and the discharging current have reached the maximum values and the charging has been completed, for a certain period of time, for example,
The integrated current value after 10 msec has elapsed is calculated. As a result, the difference between the integrated values in the normal state and the abnormal state can be increased, and the two can be discriminated from each other more easily and clearly. As a result, FIG.
As shown in (d), a predetermined judgment reference value is set in advance, and when the judgment reference value is exceeded, it is determined as abnormal, that is, the multilayer film 1 is defective, and when the judgment reference value is not exceeded. Therefore, it can be determined that the multilayer film 1 is normal, that is, the multilayer film 1 has no defect.

As described above, in the film defect detecting method and the defect detecting apparatus according to the present embodiment, by providing the integrated current judging circuit 25c as the quality judging means 25, the presence / absence of the defect on the multilayer film 1 can be simply judged. Instead of comparing the peak values of the charging current, the integrated value of the current for a certain period is calculated and compared to make the determination. That is, when the multilayer film 1 has a defect, the integrated value of the current flowing between the electrodes for a certain period becomes larger than that in the normal case where there is no defect. Therefore, by comparing and determining the integrated value. The presence or absence of defects in the multilayer film 1 can be accurately detected regardless of the peak value of the current.

As a result, it is difficult to distinguish the peak value of the current detected by the ammeter 23 due to the increase of the charging current due to the metal film layer 1d of the multilayer film 1 and the aerial and accidental air discharge. Even in such a case, the defects of the multilayer film 1 can be reliably detected by comparing the integrated values of the currents, and accurate pass / fail determination can be performed. Especially, after the charging current reaches the maximum value and charging is completed, the integrated current value after a lapse of a certain time is calculated to make a determination, thereby ignoring the influence of air discharge, etc. that occurs sporadically or accidentally. Therefore, the quality of the multilayer film 1 can be determined more reliably and accurately. Moreover, in the present embodiment, since the integral value of the charging current is calculated and determined by the integral current determining circuit 25 having the same configuration as the existing circuit, a special device, a complicated means, etc. are separately required. Without doing so, the quality of the multilayer film 1 can be accurately determined using the existing device.

In the defect detecting apparatus 20 of this embodiment, as in the case of the first embodiment, the rise time of voltage application to the multilayer film 1 is delayed for the high voltage power supply 21 which is the voltage applying means. It can also be configured.
In this way, the high-voltage power supply 21 delays the rise time of the applied voltage up to the maximum value, so that the charging current of the multilayer film 1 having the metal film layer 1d can be particularly reduced, and the multilayer film 1 Also in the present embodiment, which determines the presence or absence of a defect based on the integrated value of the charging current, the peak value of the charging current can be lowered to clarify the difference between the discharge current and the peak value. It is possible to make a more accurate pass / fail judgment.

[Third Embodiment] A third embodiment of the film defect detection method and the film defect detection apparatus according to the present invention will be described with reference to FIGS. 6 and 7. Figure 6
FIG. 4 is a schematic front view schematically showing a defect detection device according to a third embodiment of the present invention. FIG. 7 is a graph part showing the applied voltage value and the integrated value of the applied voltage decrease amount detected by the defect detecting method and apparatus according to the present embodiment.

As shown in FIG. 6, the film defect detecting method and apparatus according to the present embodiment is a modification of the above-described first embodiment. As the defect detecting apparatus 20, a high voltage power source 21 and an electrode are used. By providing a high withstand voltage resistor 28 connected in series between them, a voltage dividing resistor 26a that detects the amount of decrease in the voltage applied to the electrodes, and a voltage drop determination circuit 26 that determines the detected amount of voltage drop, The quality of the film is determined by calculating and determining the amount of voltage decrease and the integral value. This is a high breakdown voltage resistor 28 between the high voltage applying device 21 which is a high voltage power source and the electrode 22.
It is utilized that the voltage applied to the electrode 22 is reduced when a charging current or a discharging current flows by connecting in series.

The voltage drop determination circuit 26 is connected to the voltage dividing resistor 26a connected in parallel to the electrode 22, and the voltage applied to the electrode 22 is lowered by detecting the voltage of the voltage dividing resistor 26a. The amount is detected, and the integrated value of the detected amount of decrease in the applied voltage is calculated. Specifically, the voltage drop determination circuit 26 includes an input unit for detecting a drop amount of a voltage applied to an electrode, a calculation unit for calculating an integrated value of a drop amount of an electrode applied voltage, a setting unit for setting a predetermined determination reference value, A comparison unit (not shown) that compares the calculated voltage decrease amount and / or the integrated value thereof with the determination reference value is provided. Then, when the amount of voltage decrease and / or the integrated value thereof is larger than a predetermined determination reference value set in advance, it is determined that the multilayer film 1 has a defect. The determination result of the voltage drop determining circuit 26 is also displayed outside in a predetermined manner.

The film quality determination method in this embodiment using the amount of decrease in the applied voltage will be described below with reference to FIGS. 6 and 7. As shown in FIG. 7, when a voltage is applied to the multilayer film 1, the applied voltage rises and falls with a certain slope in a normal state where there is no defect on the film. On the other hand, if there are defects such as cracks on the multilayer film 1, a large discharge current will flow, and this will reduce the applied voltage. As a result, the discharge stops, the voltage rises again, and the discharge current flows, so that the discharge is repeatedly repeated (see "abnormality" shown in FIG. 7). Therefore, in the voltage drop determination circuit 26, the presence or absence of a defect on the multilayer film 1 can be reliably detected by calculating the amount of decrease in the applied voltage and / or the integrated value thereof.

Specifically, first, the voltage drop determination circuit 26
Then, the amount of decrease in the voltage applied to the electrode 22 and its integrated value are calculated via the voltage dividing resistor 26a. As shown in FIG.
In an abnormal case where the voltage rises and falls repeatedly, the integrated value becomes larger than in the normal state where the voltage does not rise and fall. Therefore,
Both can be clearly discriminated by comparing and determining the calculated integral values of the voltage drop amount. In the present embodiment, as shown in FIG. 7, a predetermined determination reference value is set in a setting unit (not shown) of the voltage drop determination circuit 26, and the detected and calculated voltage drop amount and its integrated value are not shown. The comparison unit compares the judgment reference value. Then, as a result of the comparison, if the judgment reference value is exceeded, it is judged as "abnormal", that is, the multilayer film 1 has a defect, and if it does not exceed the judgment reference, "normal", that is, it is judged that the multilayer film 1 has no defect. It has become so.

As described above, the voltage drop amount and the integrated value thereof when the multilayer film 1 has a defect are larger than the voltage drop amount and the integrated value when the multilayer film 1 has no defect. It becomes possible to determine the presence or absence of defects. As a result, even when the charging current increases or the air discharge occurs, the voltage drop determination circuit 26 calculates and compares the amount of decrease in the applied voltage and its integrated value,
It is possible to reliably detect a defect in the multilayer film 1.

As described above, according to the film defect detecting method and the defect detecting apparatus of the present embodiment, the voltage drop determining circuit 26 for detecting and calculating the amount of decrease in the applied voltage.
By providing the above, it is possible to determine the presence or absence of a defect on the film by the amount of voltage drop of the applied voltage, not by the peak value of the charging current. In particular, the metal film layer 1 of the multilayer film 1 can be determined.
Accurate quality determination can be performed without being affected by the increase in charging current due to d. As a result, the quality of the film can be reliably and accurately determined by comparing the amount of decrease in the applied voltage without being affected by the magnitude of the charging current and the peak value of the current due to accidental air discharge.

In particular, in this embodiment, since the integrated value of the amount of decrease in the applied voltage is calculated and compared, a defective portion in which the voltage repeatedly rises and falls and a normal portion in which such voltage rise and fall do not occur. And can be reliably distinguished, and a more accurate film quality determination can be performed. Moreover,
In the present embodiment, the voltage drop determination circuit 26 having the same configuration as the existing circuit is used to calculate and determine the amount of reduction of the applied voltage and the integrated value, so that a special device or complicated means is required separately. The quality of the film can be accurately determined using the existing device. In the present embodiment, in the voltage drop determination circuit 26,
Both the detection of the amount of decrease in applied voltage and the calculation of its integrated value are performed.If the peak value of the amount of decrease in applied voltage is compared to distinguish between normal and abnormal conditions, the integration is performed. The calculation of the value can be omitted.

Further, in the defect detecting apparatus 20 of the present embodiment, as in the case of the first embodiment, the high voltage power supply 21 as the voltage applying means delays the rise time of voltage application to the film. You can also do it. In this way, the high voltage power supply 21 delays the rise time of the applied voltage up to the maximum value, so that the charging current of the multilayer film 1 having the metal film layer 1d can be particularly reduced, and the multilayer film 1 Also in the present embodiment in which the presence or absence of a defect is determined based on the amount of voltage drop of the applied voltage, the peak value of the charging current can be lowered to clarify the difference between the discharge current and the peak value. It is preferable as a defect detection device that can detect defects from both sides of the voltage value and the voltage value and can perform more accurate defect determination.

It is needless to say that the film defect detection method and apparatus of the present invention are not limited to the above-mentioned embodiments, and various modifications can be made within the scope of the present invention. For example, in each of the above-described embodiments, the defect detection device when the film is subjected to the spout molding process has been described as an example, but the invention is not particularly limited to the case where the spout molding process is performed. Further, in each of the above-described embodiments, as the inspection target, a multilayer film having a metal film layer as an inner layer has been described as an example, but the defect detection method and the defect detection device according to the present invention are applicable to a film having no metal film layer. As a matter of course, the presence / absence of a defect on the film can be detected easily and surely, and the quality can be accurately determined.

[0079]

As described above, according to the film defect detecting method and the defect detecting apparatus of the present invention, the rise time of the applied voltage is delayed and the integral value of the charging current and the voltage drop amount is obtained. As a result, it is possible to eliminate the increase in charging current due to the metal film layer of the inner layer of the multilayer film and the influence of air discharge. This makes it possible to easily and surely detect and determine the presence / absence of a defect in the multilayer film having the metal film layer, which is particularly suitable for determining the defect in the multilayer film to be spout-molded.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a film defect detection apparatus according to a first embodiment of the present invention, and FIG. 1A is a schematic view showing a film spout molding processing apparatus including the defect detection apparatus according to the present embodiment. In a plan view, (b) is a schematic front view schematically showing the defect detection device in (a).

FIG. 2 is a schematic front view schematically showing an electrode portion of the defect detection device according to the first embodiment of the present invention, where (a) shows a case where the film has no defect and (b) shows a case where there is a defect. is there.

FIG. 3 is a schematic front view schematically showing a defect detection device according to a second embodiment of the present invention.

FIG. 4 is a graph part showing applied voltage, charge current, discharge current and integrated current values detected by the defect detecting method and apparatus according to the second embodiment of the present invention.

5 is a graph diagram schematically showing the relationship among the applied voltage, the charging current, the discharging current, and the integrated current value shown in FIG.

FIG. 6 is a schematic front view schematically showing the defect detection device according to the third embodiment of the present invention.

FIG. 7 is a graph part showing an applied voltage value and an integrated value of an applied voltage decrease amount detected by the defect detecting method and apparatus according to the third embodiment of the present invention.

FIG. 8 is an external view of a multi-layer film container that has been subjected to a spout molding process. FIG. 8 (a) shows a state before laminating the container, and FIG. 8 (b) shows a completed state of the container. There is.

9 is a cross-sectional view taken along the line AA shown in FIG.

[Explanation of symbols]

1 Multi-layer film 2 Injection molding part 3 containers 10 spout molding machine 20 Defect detection device 21 High voltage power supply 22 electrodes 22a Conductive brush electrode 22b metal electrode 23 Ammeter 24 Pass / fail judgment circuit 25 Pass / fail judgment means 25c Integrated current judgment circuit 26 Voltage drop determination circuit 30 Static eliminator 40 bag making machine

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2G060 AA08 AA20 AE01 AF02 AF10                       AG11 EA07 EB05 EB06 HC07                       HC12 KA11

Claims (13)

[Claims] 1. A method for detecting a defect in a film, which comprises applying a voltage in a thickness direction of the film while delaying a rise time, and when a current flowing at this time exceeds a predetermined value, A method for detecting a defect in a film, comprising determining that the film has a defect. 2. The film defect detecting method according to claim 1, wherein the predetermined value is a current value flowing when the film has no defect. 3. A method of detecting a defect in a film, comprising applying a voltage in a thickness direction of the film, calculating an integral value of a current flowing at this time, and calculating an integral value of the current to a predetermined value. A method for detecting a defect in a multilayer film, comprising determining that the film has a defect when exceeding the limit. 4. The film defect detection method according to claim 3, wherein an integrated value of the current after a predetermined time has elapsed is calculated after the current flowing when a voltage is applied to the film reaches a maximum value. 5. A method for detecting a defect in a film, wherein a voltage is applied in a thickness direction of the film, and a decrease amount of the applied voltage is calculated, and when the calculated voltage decrease amount exceeds a predetermined value. In addition, a method for detecting a film defect is characterized in that the film is determined to have a defect. 6. The film according to claim 5, wherein the integrated value of the voltage drop amount is calculated, and when the calculated integrated value of the voltage drop amount exceeds a predetermined value, it is determined that the film has a defect. Defect detection method. 7. The film defect detection method according to claim 3, 4, 5 or 6, wherein a voltage is applied to the film while delaying the start-up time. 8. An apparatus for detecting defects in a film, comprising voltage applying means for applying a voltage in the thickness direction of the film while delaying a rise time, and a voltage applying means for applying a voltage. The current detection means for detecting the flowing current and the current detected by the current detection means are compared with a predetermined determination reference value, and when the detected current is larger than the determination reference value, the film has a defect. A defect detecting apparatus for a film, comprising: a quality determining unit that determines that the film is defective. 9. An apparatus for detecting defects in a film, comprising voltage applying means for applying a voltage in the thickness direction of the film, and current detecting means for detecting a current flowing when the voltage is applied by the voltage applying means. And calculating an integral value of the current detected by the current detecting means, comparing this integral value with a preset predetermined judgment reference value, and when the integral value is larger than the judgment reference value,
A defect detecting device for a film, comprising: a quality determining unit that determines that the film has a defect. 10. An apparatus for detecting a defect in a film, comprising: voltage applying means for applying a voltage in the thickness direction of the film; and a decrease amount of the voltage applied by the voltage applying means, and detected. Comparing the amount of decrease in voltage with a predetermined determination reference value set in advance, when the amount of decrease in voltage is larger than the determination reference value, it is determined whether the film has a defect determination means, Characteristic film defect detection device. 11. The quality determining means calculates an integrated value of the detected voltage drop amount and compares the integrated value with a preset predetermined determination reference value, and the integrated value is larger than the determination reference value. 11. The film defect detection device according to claim 10, wherein it is sometimes determined that the film has a defect. 12. The film defect detection device according to claim 9, 10 or 11, wherein said voltage application means applies a voltage in the thickness direction of said film while delaying the rise time. 13. The film defect detection device according to claim 8, 9, 10, 11 or 12, wherein at least one of the pair of electrodes provided in the voltage applying means is a conductive brush electrode.