JP4405850B2 - Seal inspection method and seal inspection apparatus - Google Patents

Description

  The present invention relates to a seal inspection method and a seal inspection apparatus for inspecting a seal state of a paper container used for milk, soft drinks, and the like.

  Conventionally, when manufacturing paper containers filled with liquid foods such as milk and soft drinks, web-like packaging materials, carton blank-like packaging materials, etc. are used. Sealing is performed by a method such as sealing, whereby a paper container is formed. For example, when using a web-like packaging material, the packaging material is first formed into a tube shape, sealed in the longitudinal direction, and then filled with liquid food in the tube-shaped packaging material at a predetermined interval, this time in the lateral direction. The container is sealed and cut to form an original container, and this original container is further formed to complete the brick-shaped paper container.

    However, in order to seal the packaging material, the packaging material is sandwiched from both sides with a predetermined clamping pressure, and heat is applied to melt the resin on the surface of the packaging material, so that the packaging material is fused. If the clamping pressure is too high, the molten resin escapes from the seal portion due to the clamping pressure, the amount of resin remaining in the seal portion is insufficient, and a sealing failure may occur. As the sealing failure occurs, liquid food in the paper container may leak, or air may enter the paper container and the quality of the liquid food may deteriorate.

  Therefore, conventionally, a seal state inspection device for inspecting the seal state of a paper container has been used. A conceptual diagram of this seal state inspection apparatus is shown in FIG. As shown in the figure, a conventional seal state inspection apparatus 100 includes two electrodes 101 and 102 arranged to face each other so as to sandwich a seal portion S of a paper container to be inspected. An inspection device 103 that detects a capacitance by applying a voltage to 102 and inspects the seal state of the seal portion is configured.

  Here, the seal portion S to be inspected is one in which the two packaging materials 105 are heated or fused by being vibrated by ultrasonic waves. A paper base 107, an adhesive polyethylene layer 108, an aluminum foil layer 109, and an inner surface polyethylene layer 110 are formed.

  The seal portion S forms an equivalent circuit as shown in FIG. 6B. When a predetermined measurement result is obtained by applying a voltage to the electrodes 101 and 102 and measuring the capacitance. Has determined that the sealing state is good, and when a predetermined measurement result is not obtained, it has been determined that the sealing state is poor.

  However, in the above-described conventional seal state inspection device, since the electrostatic capacity of the entire seal portion S in which both of the two packaging materials 105 are overlapped and fused is measured, the outer surface not related to the quality of the seal state. There has been a problem that the electrostatic capacitance due to layers such as the polyethylene layer 106, the paper base 107, and the polyethylene layer 108 for adhesion is measured as noise.

  The present invention has been made to solve such a conventional problem, and the object of the present invention is to measure the capacitance by energizing the aluminum foil layer inside the packaging material. An object of the present invention is to provide a seal inspection method and a seal inspection apparatus that can perform measurement without being affected by the material outside the aluminum foil layer, and thereby can accurately inspect the seal state of the seal portion.

In order to achieve the above object, the invention described in claim 1 is a seal inspection method for inspecting a seal portion of a paper container formed by a packaging material formed by laminating a dielectric material and a conductive material. An incision step of cutting the paper container so as to be divided into two regions partitioned by the seal portion formed on the top portion and the bottom portion of the paper container, and the conductive material of the two regions A capacitance detection step of detecting a capacitance of the seal portion by energization; and a seal state determination step of determining a seal state of the seal portion based on the capacitance, the capacitance detection step Is characterized in that each of the two regions is immersed in a conductive liquid that electrically insulates, and the conductive material is energized through the conductive liquid to detect the capacitance of the seal portion.

According to a second aspect of the present invention, in the capacitance detection step of the seal inspection method according to the first aspect, the conductive material is energized by piercing each of the two regions with a needle-like electrode. It is characterized by detecting the electrostatic capacity of the seal portion.

According to a third aspect of the present invention, in the incision step of the seal inspection method according to the first or second aspect , the paper container is cut so that the upper and lower sides of the paper container are separated, and the left and right ends of the cut paper container are cut. It is characterized by separating.

According to a fourth aspect of the present invention, there is provided a seal inspection apparatus for inspecting a seal portion of a paper container formed by a packaging material formed by laminating a dielectric material and a conductive material, the top of the paper container The two electrolytically insulated electrodes are cut open so as to be divided into two regions separated by the seal portion formed in the bottom portion and the bottom portion, and the two regions of the paper container are separately immersed A liquid tank, an electrode for energizing each conductive material in each of the two regions via a conductive liquid filled in the two electrolyte tanks, and detecting the capacitance of the seal portion by energizing the electrode And a seal state determination unit that determines a seal state of the seal portion based on the capacitance detected by the capacitance detection unit.

  According to the invention of claim 1, since the capacitance is measured by energizing the conductive material inside the packaging material, the capacitance is measured without being affected by the material outside the conductive material. Thus, the seal state of the seal portion can be inspected with high accuracy.

Also, by energizing the cut paper container by immersing it in a conductive liquid, it is possible to easily energize the conductive material inside the packaging material, thereby easily detecting the capacitance of the seal portion. .

According to the second aspect of the present invention, the electrostatic capacity of the seal portion can be easily detected without preparing other materials such as an electrolytic solution by directly piercing the needle-like electrode and energizing it.

According to the invention of claim 3 , the paper container to be inspected can be opened and inspected, thereby enabling a state in which the seal inspection by the seal inspection method of the present invention can be performed. .

According to the invention of claim 4, since the capacitance is measured by energizing the conductive material inside the packaging material, the capacitance is measured without being influenced by the material outside the conductive material. Thus, the seal state of the seal portion can be inspected with high accuracy.

  Furthermore, by energizing the opened paper container by immersing it in a conductive liquid, it is possible to easily energize the conductive material inside the packaging material, thereby easily detecting the capacitance of the seal portion. .

  Examples of the conductive liquid in the present invention include an electrolyte, a liquid electrolyte, a conductive fluid polymer, and the like. Examples of the electrolyte include sodium chloride, inorganic salts such as potassium chloride and sodium sulfate, and organic salts such as lime acid. Solvents include solvents such as water, alcohol, ketone, and amine. In the following embodiment, an electrolyte solution of sodium chloride will be described.

  The conductive material in the present invention is a layer of the laminated packaging material forming the container, and includes, for example, a metal layer such as a steel foil, an aluminum foil, and an aluminum vapor deposition layer. In the following embodiments, the aluminum foil will be described.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings. FIG. 1 is a flowchart showing a seal inspection method according to the present invention.

  As shown in the figure, in the seal inspection method of the present embodiment, first, an incision step is performed to open a paper container to be inspected so that it can be inspected (S101).

  Here, this incision process will be described with reference to FIG. As shown in the figure, in the incision step, first, the flap of the paper container (S201) formed in a brick shape is peeled off (S202), and the contents are cut in the middle between the top and bottom parts of the paper container Is discharged (S203). However, in FIG. 2, it is shown that the paper container is cut in the vicinity of the middle of the top and bottom of the paper container. It may not be near the upper and lower middle of the container.

  Next, the left and right ends of the paper container are longitudinally cut by about 1 mm (S204). And it isolate | separates into a top part and a bottom part (S205), it bends at right angle with a LS seal part and a crease line (S206), and an incision process is complete | finished. Here, as shown in step S <b> 206 of FIG. 2, the paper container after the incision process is divided into two regions X and Y partitioned by the seal portion S. The region X and the region Y are regions used for energization by immersing in an electrolytic solution or piercing a needle-like electrode as will be described later. Moreover, if the seal | sticker part S does not partition the area | region X and the area | region Y, an electric current will flow, when it supplies with electricity, and the electrostatic capacitance of the seal | sticker part S cannot be measured.

  As described above, since the paper container to be inspected is cut open by the incision process so as to be inspected, the seal inspection by the seal inspection method of the present embodiment can be performed.

  Next, a capacitance detection step of detecting the capacitance of the seal portion S using the cut paper container is performed (S102).

  Here, the packaging material forming the paper container will be described with reference to FIG. The packaging material 31 is directed from the inside to the outside, for example, a first resin layer 32 formed as an inner layer by a resin such as polyethylene, an aluminum foil layer 33 formed as a barrier layer, a paper base material 34, a resin such as polyethylene, etc. Has a laminated structure composed of the second resin layer 35 formed as an outer layer. In the seal portion S, the first resin layers 32 of the two packaging materials 31 are overlapped with each other, and a resin constituting the first resin layer 32 by heating or ultrasonic vibration, for example, polyethylene is fused at the fusion portion 36. It is fused.

  In this seal portion S, the first resin layer 32 disposed therebetween is formed by a dielectric material by energizing the aluminum foil layer 33 formed of a conductive material. Function as.

  Therefore, in the capacitance detection step (S102), the capacitance of the seal portion S is detected by energizing the aluminum foil layers 33 in the two regions X and Y of the cut paper container.

  As a method for detecting this capacitance, as shown in FIG. 4, the two regions X and Y are immersed in different electrolytic solutions, and the aluminum foil layer 33 is energized through the electrolytic solution using the LCR meter 41 or the like. As a result, the capacitance of the seal portion S can be detected.

  Thus, by energizing the cut paper container by immersing it in the electrolytic solution, the aluminum foil layer 33 inside the packaging material can be easily energized, and the electrostatic capacity of the seal portion S can be detected.

  Alternatively, the electrostatic capacity of the seal portion S can be detected by inserting needle-like electrodes directly into the two regions X and Y and energizing the aluminum foil layer 33.

  In this way, by directly inserting the needle-like electrode and energizing it, the electrostatic capacity of the seal portion S can be easily detected without preparing other materials such as an electrolytic solution.

  When the electrostatic capacity of the seal portion S is detected in this way, a seal state determination step for determining the seal state of the seal portion S based on the detected electrostatic capacity is performed (S103).

The capacitance C detected in the capacitance detection step (S102) is defined as s for the area of the aluminum foil layer 33 in the seal portion S, and ε, 2 for the dielectric constant of the material sandwiched between the aluminum foil layers 33. If the distance between the two aluminum foil layers 33 is d,
C = ε · s / d (1)
It is represented by

  Here, as for the capacitance C, when the material, thickness, etc. of the first resin layer 32 are different, the dielectric constant ε changes and the capacitance C changes. Further, when the sealing conditions for sealing the seal portion S, for example, the melting temperature of the resin, the clamping pressure for sealing, and the like are different, the distance d between the aluminum foil layers 33 changes, and the capacitance C changes. For example, the higher the melting temperature or the higher the clamping pressure, the greater the amount of the resin melted in the seal portion S that escapes to both sides of the seal portion S, and the thickness of the fused portion 36 decreases accordingly. Therefore, the distance d between the aluminum foil layers 33 is shortened, and the capacitance C is increased accordingly.

  If the method for sealing the seal portion S is different, the degree of fusion of the fusion portion 36 changes, and the capacitance C changes. In this case, there are two sealing methods for the sealing portion S: a block sealing method and a sealing sealing method. For example, when sealing is performed by the block sealing method, the resins of the first resin layers 32 are not fused. Therefore, the fusion part 36 is hardly formed, and the first resin layers 32 are merely attached to each other. Therefore, the amount of resin in the seal part S is not reduced, and the space between the aluminum foil layers 33 is reduced. The distance d does not change, and the capacitance C does not change. On the other hand, when sealing is performed by a hermetic sealing method, the resins of the first resin layers 32 are fused, and the packaging materials 31 are fused. In this case, the amount of resin in the seal portion S is reduced, the distance d between the aluminum foil layers 33 is shortened, and the capacitance C is increased accordingly.

  Thus, since the electrostatic capacitance C changes with the attribute of the 1st resin layer 32, sealing conditions, a sealing method, etc., the quality of a sealing state is determined by detecting the electrostatic capacitance C of the seal | sticker part S. Can do.

Therefore, in the seal state determination step (S103), the reference capacitance Cr is set in consideration of the above-described factors, and the absolute difference between the reference capacitance Cr and the detected capacitance C is absolute. The value is compared with a predetermined threshold value ΔC. | C−Cr | <ΔC (2)
When it becomes smaller than the threshold value ΔC, it is determined that the seal state of the seal portion S is good. On the contrary, when the threshold value ΔC is exceeded, it is determined that the seal state of the seal portion S is defective, and the inspection by the seal inspection method of the present embodiment ends.

  As described above, in the seal inspection method according to the present embodiment, since the capacitance is measured by energizing the aluminum foil layer 33 inside the packaging material 31, the influence of the material outside the aluminum foil layer 33 is affected. The electrostatic capacity can be measured without receiving, so that the seal state of the seal portion S can be accurately inspected.

  The seal inspection method of the present invention has been described based on the illustrated embodiment. However, the present invention is not limited to this, and each process can be replaced with any process having the same function.

  Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 5 is a block diagram showing a configuration of a seal inspection apparatus according to the second embodiment of the present invention. As shown in the figure, the seal inspection apparatus 51 of the present embodiment includes two electrolytic solution containers 52 and 53 for immersing a previously opened paper container, and an electrolytic solution filled in the electrolytic solution containers 52 and 53. Electrodes 54 and 55 for energizing the conductive material of the paper container via the electrode, and a capacitance detection unit (capacitance detection means) 56 for detecting the capacitance of the seal S by energization of the electrodes 54 and 55. The seal state determination unit (seal state determination means) 57 determines the seal state of the seal portion S based on the capacitance detected by the capacitance detection unit.

  Here, the paper container to be inspected by the seal inspection device 51 is cut and opened in advance, and the cut and opened paper container is cut and opened so as to be divided into two regions X and Y separated by the seal portion S. .

  However, since the paper container is cut and opened by the same method as the cutting step (S101) in the seal inspection method of the first embodiment described above, detailed description thereof is omitted.

  When the two regions X and Y of the cut paper container are separately immersed in the two electrolytic solution containers 52 and 53 and a voltage is applied from the electrodes 54 and 55, the aluminum foil layer 33 is energized through the electrolytic solution. The seal portion S functions as a capacitor in which the first resin layer 32 is sandwiched between the aluminum foil layers 33.

  The electrostatic capacitance detection unit 56 detects the electrostatic capacitance C of the seal portion S, and the seal state determination unit 57 determines the quality of the seal state of the seal portion S based on the detected electrostatic capacitance C.

  However, since the seal state determination method is determined by the same method as the seal state determination step (S103) in the seal inspection method of the first embodiment described above, detailed description thereof is omitted.

  As described above, in the seal inspection apparatus 51 according to the present embodiment, since the capacitance is measured by energizing the aluminum foil layer 33 inside the packaging material 31, the material is outside the aluminum foil layer 33. Capacitance C can be measured without being affected, and thus the seal state of the seal portion S can be accurately inspected.

  Further, in the seal inspection apparatus 51 according to the present embodiment, the aluminum foil layer 33 inside the packaging material 31 can be easily energized by immersing the cut paper container in the electrolytic solution and energizing it. It becomes possible to detect the capacitance C of the seal portion S.

  The seal inspection apparatus of the present invention has been described based on the illustrated embodiment. However, the present invention is not limited to this, and the configuration of each part is replaced with an arbitrary configuration having the same function. Can do.

  This is a seal inspection method for inspecting a seal portion of a paper container, and inspecting the seal state of the seal portion with high accuracy by energizing the aluminum foil layer inside the packaging material for forming the paper container and measuring the capacitance. It is extremely useful as a technique for this purpose.

It is a flowchart for demonstrating the seal | sticker test | inspection method which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating the incision process in the seal | sticker test | inspection method of this invention. It is sectional drawing which shows the paper container cut open by the incision process of the seal | sticker test | inspection method of this invention. It is a figure for demonstrating the electrostatic capacitance detection process in the seal | sticker test | inspection method of this invention. It is a block diagram which shows the seal | sticker inspection apparatus which concerns on the 2nd Embodiment of this invention. It is a conceptual diagram which shows the structure of the conventional seal state inspection apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 31 Packaging material 32 1st resin layer 33 Aluminum foil layer 34 Paper base material 35 2nd resin layer 36 Fusion part 41 LCR meter 51 Seal test | inspection apparatus 52, 53 Electrolyte tank 54, 55 Electrode 56 Electrostatic capacity detection part (Capacitance detection means)
57 Seal state determination unit (seal state determination means)
DESCRIPTION OF SYMBOLS 100 Seal state inspection apparatus 101,102 Electrode 103 Inspection apparatus 105 Packaging material 106 Outer surface polyethylene layer 107 Paper base material 108 Adhesive polyethylene layer 109 Aluminum foil layer 110 Inner surface polyethylene layer

Claims (4)

A seal inspection method for inspecting a seal portion of a paper container formed by a packaging material formed by laminating a dielectric material and a conductive material,
An incision step of cutting the paper container so as to be divided into two regions partitioned by the seal part formed on the top part and the bottom part of the paper container,
A capacitance detection step of energizing the conductive material of the two regions to detect the capacitance of the seal portion;
A seal state determination step of determining a seal state of the seal portion based on the capacitance ;
In the capacitance detection step, the two regions are respectively immersed in a conductive liquid that electrically insulates, and the conductive material is energized through the conductive liquid to detect the capacitance of the seal portion. A seal inspection method characterized by the above. The capacitance detection step detects the capacitance of the seal portion by energizing the conductive material by inserting a needle-shaped electrode into each of the two regions. The seal inspection method described. 3. The seal inspection method according to claim 1, wherein in the cutting step, the paper container is cut so that the top and bottom of the paper container are separated from each other, and both left and right ends of the cut paper container are cut and separated. A seal inspection device for inspecting a seal portion of a paper container formed by a packaging material formed by laminating a dielectric material and a conductive material,
The paper container is cut open so as to be divided into two regions separated by a seal portion formed at the top and bottom of the paper container, and the two regions of the paper container are immersed separately and electrically insulated Two electrolyte baths to
An electrode for energizing each conductive material in the two regions via a conductive liquid filled in the two electrolyte baths;
  A capacitance detecting means for detecting a capacitance of the seal portion by energization of the electrode;
  Seal state determination means for determining a seal state of the seal portion based on the capacitance detected by the capacitance detection means;
A seal inspection apparatus comprising:

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