JP4925178B2 - Container seal defect inspection method - Google Patents

Description

  The present invention relates to a container in which a flange portion of a container body and a sheet-like lid are integrally bonded by heat sealing or the like, and a method for inspecting a defect in a seal portion between the container body and the lid In particular, the present invention relates to a method for inspecting a sealing failure of a container so that all of the continuously conveyed containers can be inspected in a non-contact manner.

A cup-shaped container in which the flange part of the container body and the sheet-like lid are bonded together by heat sealing, etc., and seal failure due to pinholes etc. in the seal part between the container body and the lid As a technique for inspecting, Patent Document 1 below inspects a sealing failure of a cup packaging container in which an upper lid (sheet-like lid) is hermetically sealed on a flange (flange) of the container. The technology about the pinhole inspection machine is described, the amorphous metal fiber electrode is brought into contact with the lower side of the seal part, the disk-like electrode is brought into contact with the center part of the upper lid, and the current is passed between the two electrodes. There is disclosed a method for inspecting a container for sealing failure such that if there is a discharge phenomenon, it is determined that the sealing is defective.
JP 2002-39907 A

  By the way, according to the conventionally known methods for inspecting a seal of a container as described above, even if residual water adheres to a container cooled with cooling water, it is surely subjected to a distinction process so that a seal failure at the seal portion is not achieved. However, the inspection method is a contact type that requires that each container be installed between both electrodes. When inspecting, there is a problem that it takes a lot of time.

  An object of the present invention is to solve the above-described problems. Specifically, for a container in which a flange portion of a container body and a sheet-like lid are integrally bonded, a large number of containers are provided. It is an object of the present invention to be able to inspect all the defective seals in each container in a non-contact manner while being conveyed by a conveyor or the like.

  In order to solve the above-described problems, the present invention provides a method for inspecting a defect in a seal portion in which a flange portion of a container body and a sheet-like lid are bonded to each other with a predetermined electric circuit constant. A wireless tag including a holding antenna coil and a capacitor and having a resonance circuit capable of obtaining a predetermined resonance frequency is provided in a seal portion between the flange portion and the lid of the container body, and the wireless tag has a predetermined By transmitting an electromagnetic wave having a resonance frequency and detecting a return electromagnetic wave having a predetermined resonance frequency returned from the wireless tag according to the transmitted electromagnetic wave, if the return electromagnetic wave cannot be detected, it is determined that the seal portion is defective. It is characterized by doing so.

  According to the sealing failure inspection method for a container of the present invention as described above, when there is no problem in the sealing part between the flange part of the container body and the sheet-like lid, the wireless tag has a predetermined resonance. When an electromagnetic wave having a frequency is transmitted, the antenna coil generates an amount of electric charge corresponding to the resonance frequency, the capacitor stores the electric charge, and an electromagnetic wave having a predetermined resonance frequency received by the antenna coil is returned with the energy.

  On the other hand, when there is a problem with the seal part between the flange part of the container body and the sheet-like lid, foreign matter such as content liquid contacts the antenna coil, the inductance of the antenna coil changes, and the predetermined As a result, the wireless tag cannot resonate with an electromagnetic wave having a predetermined resonance frequency, and accordingly, a return electromagnetic wave having a predetermined resonance frequency is not transmitted.

  Therefore, an electromagnetic wave having a predetermined resonance frequency is transmitted to each of the wireless tags of a large number of containers being conveyed by a conveyor, and a response electromagnetic wave having a predetermined resonance frequency returned from the wireless tag in response to the transmitted electromagnetic waves is detected. Thus, when the return magnetic wave cannot be detected, it can be determined that the seal portion between the flange portion of the container body and the sheet-like lid is defective. As a result, while a large number of containers are being conveyed by a conveyor or the like, it is possible to easily inspect all the defective seals in each container in a non-contact manner.

  Furthermore, when there is a problem with the seal part and a return electromagnetic wave with a predetermined resonance frequency cannot be detected, there are various types of resonance circuits for wireless tags whose impedance has changed due to contact with foreign matter such as liquid contents. By transmitting an electromagnetic wave having a frequency to cause the wireless tag to resonate, the degree of failure at the seal portion can be determined by the magnitude of the frequency of the transmitted electromagnetic wave from which the resonance is obtained.

  In addition, about the antenna coil and capacitor | condenser which comprise a wireless tag, by forming thinly by printing, it does not affect the sealing performance in a seal part, but can maintain a favorable seal part. Further, by extending the antenna coil to the center side of the sheet-like lid, a capacitor having a large capacity can be formed, and the inspection can be satisfactorily performed with a highly sensitive wireless tag.

  For containers in which the flange part of the container body and the sheet-like lid are integrally bonded, while a large number of containers are being transported by a conveyor, etc., defective seals in each container can be detected without contact. The objective of enabling 100% inspection, as specifically shown in the following embodiment as the best mode, is a resonant circuit comprising an antenna coil and a capacitor having a predetermined electric circuit constant to obtain a predetermined resonance frequency. The wireless tag formed with is provided in the seal portion between the flange portion of the container body and the lid, and an electromagnetic wave having a predetermined resonance frequency is transmitted to the wireless tag, and the wireless tag returns in response to the transmitted electromagnetic wave. This is realized by detecting a return electromagnetic wave having a predetermined resonance frequency and determining that the seal portion is defective when the return electromagnetic wave cannot be detected.

  For the container to which the container seal failure inspection method of the present invention is applied, for example, as a container body, a single-layer or multilayer synthetic resin sheet is pressed against a mold by a pressure forming method or a vacuum forming method. Cup-shaped containers and cup-shaped containers molded by injecting synthetic resin between molds, etc., and such cup-shaped containers extend horizontally outward from the upper end of the container body opening. After the contents are filled in the container body, the sheet-like lid is integrally bonded to the flange part of the container body by heat bonding or the like by heat sealing. It will be sealed.

  The material of the container body is not particularly limited as long as heat sealing at the flange is possible, but olefin-based resins and polyester-based resins are generally used, and the layer structure is A single layer structure may be used, and a multilayer structure in which an EVOH resin and a polyamide resin excellent in gas barrier properties are sandwiched may be used.

  One embodiment of the container sealing failure inspection method of the present invention applied to the cup-shaped container as described above will be described below. In addition, regarding the cup-shaped container to which the present invention is applied, the cross-sectional shape of the container main body and the planar shape of the flange portion may be circular, substantially square, or substantially rectangular, but in this embodiment, are substantially rectangular. .

  In such a cup-shaped container, as shown in FIG. 1, a sheet-like lid 4 is integrally heat-bonded to the flange portion 3 of the container body 2 by heat sealing. The body 4 is a sheet having a thickness of about 100 μm made of a material that can be heat-sealed. As described above, the antenna coil 5 is printed with a conductive ink made of synthetic resin in which metal powder that is harmless to the human body such as iron powder, silver powder, and gold powder is mixed.

  In the present embodiment, the antenna coil 5 is printed on an eight-fold coil, the coil line width is about 0.4 mm, and the interval between the coil lines is about 0.8 mm. The length on the short side is about 74 mm, the length on the long side is about 116 mm, and the inductance thereof has a value of 17.6 μH.

  In order to make such an antenna coil 5 into a resonant circuit, as shown in FIG. 2, in the vicinity of the coil wire end portion on the outer edge side of the antenna coil 5, one line end portion of the eight-fold coil wire is left. Further, the insulating chip 6 is formed by printing with resin ink so as to cover the seven lines with a small area. The coil full width of the antenna coil 5 is smaller than the insulating chip 6 from above the insulating chip 6. The conductive plate portion 7 is formed by printing with conductive ink so as to cover, and the conductive plate portion 7 is connected to the coil wire end portion on the outer edge side of the antenna coil 5, thereby forming the capacitor 8. ing. In this embodiment, the capacitance of the capacitor 8 has a value of 10.7 pf.

  That is, in the sealing failure inspection method for a container according to the present embodiment, the resonance circuit composed of the antenna coil 5 and the capacitor 8 is previously formed on the sheet-like lid body 4 by printing, as described above. After the contents are filled, when the sheet-like lid 4 is heat-sealed to the flange 3 of the container body 2, as shown in FIG. 3, the gap between the flange 3 and the lid 4 of the container body 2 A wireless tag including a resonance circuit including the antenna coil 5 and the capacitor 8 (the antenna coil 5, the insulating chip 6, and the conductive plate portion 7) is provided on the seal portion.

  Then, an electromagnetic wave having a predetermined resonance frequency is transmitted to the container provided with the wireless tag as described above, and a return electromagnetic wave having a predetermined resonance frequency returned from the wireless tag according to the transmitted electromagnetic wave is detected. When the return magnetic wave is detected, it is determined that there is no problem in the seal portion. Specifically, in this embodiment, an electromagnetic wave having a resonance frequency of about 13.56 MHz is transmitted to the wireless tag with a dip meter, and an amount of electric charge corresponding to the resonance frequency is generated in the antenna coil 5, and the capacitor 8 transfers the electric charge. When the electromagnetic wave having a resonance frequency of about 13.56 MHz received by the antenna coil 5 is returned with the energy stored therein, and the returned electromagnetic wave is received by the dip meter, it is determined that there is no problem in the seal portion. is doing.

  On the other hand, if there is a problem in the seal portion and foreign matter such as content liquid is in contact with the antenna coil 5, the inductance of the antenna coil 5 of the wireless tag changes and the impedance changes accordingly. Since the resonance circuit of the tag does not respond to the electromagnetic wave of the resonance frequency and the electromagnetic wave of the predetermined resonance frequency is not detected even if the electromagnetic wave of the predetermined resonance frequency is transmitted, the seal part is defective in that case. Judging that there is.

  According to the container sealing failure inspection method of the present embodiment as described above, first, any of the antenna coil 5 and the capacitor 8 (insulating chip 6 and conductive plate portion 7) constituting the wireless tag provided in the container is used. Since they are thinly formed by printing, the sealability at the seal portion can be satisfactorily maintained without substantially affecting the sealability at the seal portion.

  And for each of a large number of containers transported by a conveyor or the like, an electromagnetic wave of a predetermined resonance frequency is transmitted to the wireless tag of each container, and the return electromagnetic wave is detected, so that the seal part of each container Since defects are being inspected, it is possible to easily inspect all the sealing defects at the seal portion of each container in a non-contact manner while many containers are being conveyed by a conveyor or the like.

  In addition, when there is a problem with the seal part and it is not possible to detect a return electromagnetic wave with a predetermined resonance frequency, and if you want to separate the level of defects (defects) in the seal part, about the container rejected as a seal defect by inspection, Transmission with resonance obtained by transmitting electromagnetic waves of various frequencies to cause resonance in the wireless tag to the resonance circuit of the wireless tag whose impedance has changed due to contact with foreign matter such as liquid content The degree of failure at the seal portion can be easily determined by the magnitude of the frequency of the electromagnetic wave.

  That is, when the number of shorts due to the contact of foreign matter such as liquid contents among a plurality of (8 in this embodiment) coil wires in the width direction of the antenna coil 5 increases, the frequency of electromagnetic waves that resonate and return increases. Therefore, it can be determined that the higher the frequency of the electromagnetic wave that is resonated and returned, the greater the degree of defects (seal failure) at the seal portion due to contact with foreign matter such as the content liquid. Specifically, when the resonance frequency is slightly higher than the predetermined resonance frequency, it can be determined that the degree of failure at the seal portion is light, while the resonance is about five times higher than the predetermined resonance frequency. In the case of frequency, about 5 out of 8 in the width direction of the antenna coil 5 are short-circuited, so that it can be determined that there is a serious defect that the content liquid is likely to leak from the seal portion.

  As described above, one embodiment of the method for inspecting a seal failure of a container according to the present invention has been described. However, the present invention is not limited to the above embodiment, and can be changed as appropriate. In the above embodiment, the wireless tag having the resonance circuit composed of the antenna coil 5 and the capacitor 8 is formed on the sheet-like lid 4 side. 3 and the number of coil wires in the width direction of the antenna coil 5 (how many coils are used) are the eight shown in the above embodiment ( The number is not limited to eight), and may be an appropriate number.

  Further, when a wireless tag having a resonance circuit composed of the antenna coil 5 and the capacitor 8 is formed on the sheet-like lid body 4, as shown in FIGS. 4 and 5, the coil wire end portion inside the antenna coil 5. The antenna coil 5 and the inner conductive portion 5a are formed by printing with a conductive ink so that is extended to the center side of the lid 4 to become a plate-like inner conductive portion 5a, and the coil wire of the antenna coil 5 is formed. An insulating chip 6 is formed by printing with resin ink so as to cover the entire coil width of the antenna coil 5 and the inner conductive portion 5a with the outer coil wire end portion remaining in the vicinity of the end portion. The conductive plate portion 7 is formed by printing with conductive ink so as to cover the entire coil width of the antenna coil 5 and the inner conductive portion 5a from above the insulating chip 6 with a smaller area than the conductive plate portion 6. May be formed by connecting to the end of the coil wire outside the antenna coil, and the antenna coil 5 is extended to the center side of the lid 4 to form the inner conductive portion 5a. By doing so, the capacitor 8 having a large capacitance can be formed, and the inspection can be satisfactorily performed by the wireless tag having high sensitivity.

The partial cross section side view which shows the right half with a cross section about an example of the container to which the inspection method of this invention is applied. The bottom view of the cover body which shows the state by which the wireless tag was formed in the lower surface of a cover body about one specific example of the wireless tag used with the test | inspection method of this invention. The partial enlarged sectional view which shows the state by which the wireless tag (capacitor part) was provided in the seal part between a container main body and a cover body about the wireless tag shown in FIG. The bottom view of the cover body which shows the state by which the wireless tag was formed in the lower surface of a cover body about the other specific example of the wireless tag used with the test | inspection method of this invention. The partial expanded sectional view which shows the part of the capacitor | condenser of the wireless tag formed in the cover body about the wireless tag shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Container 2 Container main body 3 Flange part 4 Cover body 5 Antenna coil 5a Inner electroconductive part 6 Insulating chip 7 Conductive plate part 8 Capacitor

Claims (4)

  In a method for inspecting a defect in a seal portion in which a flange portion of a container body and a sheet-like lid are bonded, an antenna coil having a predetermined electric circuit constant and a capacitor are used to obtain a predetermined resonance frequency. A wireless tag having a resonance circuit formed is provided in a seal portion between the flange portion and the lid of the container body, and an electromagnetic wave having a predetermined resonance frequency is transmitted to the wireless tag, and the wireless tag is wirelessly transmitted according to the transmitted electromagnetic wave. By detecting a return electromagnetic wave having a predetermined resonance frequency returned from a tag, if the return electromagnetic wave cannot be detected, it is determined that the seal portion is defective. .   When an electromagnetic wave having a predetermined resonance frequency is transmitted to the wireless tag and a response electromagnetic wave having a predetermined resonance frequency returned from the wireless tag according to the transmitted electromagnetic wave is detected, The resonance circuit is searched for a transmission electromagnetic wave from which resonance is obtained, and the degree of failure in the seal portion is determined by the magnitude of the frequency of the transmission electromagnetic wave from which resonance is obtained. The container sealing failure inspection method according to claim 1.   An antenna coil is formed by printing with conductive ink on either the flange portion of the container body or the sheet-like lid, and one coil is formed near the coil wire end portion of the antenna coil. An insulating chip is formed by printing with resin ink so as to cover the entire coil width of the antenna coil leaving the wire end portion, and the coil of the antenna coil is formed on the insulating chip with a smaller area than the insulating chip. A conductive plate portion is formed by printing with conductive ink so as to cover the entire width, and the conductive plate portion is connected to one coil wire end portion of the antenna coil, thereby forming a capacitor. The method for inspecting a sealing failure of a container according to claim 1 or 2.   The antenna coil and the inner side are printed with conductive ink so that the coil wire end portion inside the antenna coil is extended toward the center side of the lid to form a plate-like inner conductive portion with respect to the sheet-like lid. Printed with resin ink so that the conductive coil is formed and the coil width of the antenna coil and the inner conductive part of the antenna coil are covered in the vicinity of the coil coil end of the antenna coil. An insulating chip is formed by printing with conductive ink so as to cover the entire coil width of the antenna coil and the inner conductive part from above the insulating chip in a smaller area than the insulating chip. 3. The container seal failure detection according to claim 1, wherein a capacitor is formed by connecting the conductive plate portion to a coil wire end portion outside the antenna coil. Method.

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