JP5796996B2 - Seal inspection method - Google Patents

Description

The present invention relates to a seal inspection method for inspecting a sealed state of a packaging bag for packaging contents such as foods, pharmaceuticals, plant seeds, and dried plants in a sealed state.

  For example, a shaving knot made by thinly cutting knots such as bonito is generally packed in a small packaging bag every predetermined amount, packed with an inert gas and sealed in a sealed state with the bag mouth sealed, It is distributed in the market. Patent Document 1 below discloses a packaging bag having a shaving node as a content.

  By the way, in this sealing process, there may occur a sealing failure that is sealed while the contents are sandwiched between the sealing portions. In the worst case, the inert gas escapes from the defective portion, and the quality of the contents deteriorates. There is a risk that the product will be on the market.

  For this reason, at the manufacturing site, immediately after the sealing process, a seal inspection is performed to check whether or not a sealing failure has occurred due to biting or the like in which the contents are sandwiched between the sealing portions. And what was certified as a non-defective product through the seal inspection is shipped, and the patent document 1 below also discloses a seal inspection method.

  When the packaging bag is a transparent bag, the seal inspection is performed by a person visually inspecting the seal portion or automatically by recognizing the seal portion with a seal inspection device including a light source and an imaging device. It has been implemented.

  With such a transparent packaging bag, the seal inspection is easy, but there are problems such as deterioration in appearance due to the contents being visible from the outside and deterioration of the contents due to light irradiation. For this reason, the packaging bag using the light shielding packaging film which has an aluminum layer is provided conventionally. If such a light-shielding packaging film is used, the contents cannot be seen from the outside of the packaging bag, and a high-grade feeling can be obtained by glossiness due to high reflectivity.

JP 2005-47547 A

  However, when a light-shielding packaging film is used, it is difficult to inspect a sealing failure due to biting because the seal portion that becomes the boundary of the packaging film to be bonded cannot be seen from the outside.

This invention is made | formed in view of such a subject, and it aims at providing the seal | sticker test | inspection method which can recognize reliably the sealing defect by biting also in the packaging bag using a light shielding packaging film. .

In order to solve the above-described problems, a seal inspection method according to the present invention seals a peripheral portion by overlapping two light shielding packaging films having at least a transparent sealant layer and a barrier layer including a light shielding metal layer. it was packaging bag which is formed by, the extending throughout substantially in the longitudinal direction the bag mouth seal region to be sealed after filling of the contents, a transparent window in which the metal layer is not present, the one In the seal inspection method for inspecting a seal failure in a bag mouth seal region of a packaging bag formed only on the light-shielding packaging film, the side on which the transparent window is formed of the packaging bag conveyed to an inspection place after sealing An irradiation step of irradiating collimated light at an incident angle of 50 ° or more and 80 ° or less with respect to the surface of the bag mouth seal region, and the bag mouth seal region of the packaging bag located at an inspection place The imaging step of sequentially photographing the bag mouth seal area including the transparent window by a line sensor installed at a position facing the surface in the vertical direction, the line sandwiching the packaging bag located at the inspection location Based on the imaging process in which the bag mouth seal region receives light from the backlight installed on the side opposite to the sensor and the captured image captured in the imaging process, the control device uses the light from the backlight. A seal failure determination step for determining whether a seal failure due to biting has occurred in the bag mouth seal region while detecting an edge of the packaging bag by being shielded from light by the packaging bag. To do.

According to the seal inspection method according to the present onset bright, it is possible to reliably detect the seal of the packaging bag defects using a light-shielding packaging film with high accuracy.

Drawing 1 is a figure showing the composition before sealing of the packaging bag concerning the embodiment of the present invention. FIG. 2 is a diagram illustrating a configuration after sealing the packaging bag according to the embodiment of the present invention. FIG. 3 is a perspective view of the packaging bag according to the embodiment of the present invention. FIG. 4 is a schematic view schematically showing a seal inspection apparatus for a packaging bag according to an embodiment of the present invention. FIG. 5 is a schematic diagram for explaining the principle of seal inspection according to the embodiment of the present invention. FIG. 6 is a diagram illustrating an image captured by the line sensor according to the embodiment of the present invention.

  First, a packaging bag according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating a configuration of a packaging bag according to the present embodiment before sealing. FIG. 1 (a) is a rear view, and FIG. 1 (b) is an AA line in FIG. 1 (a). A cross-sectional view is shown. 2A and 2B are diagrams illustrating a configuration after sealing of the packaging bag according to the present embodiment, in which FIG. 2A is a rear view, and FIG. 2B is a cross-sectional view taken along line BB in FIG. The figure is shown.

  FIG. 3 is an enlarged perspective view showing a bag mouth portion of the packaging bag according to the present embodiment. FIG. 3 (a) shows the packaging bag before sealing, and FIG. 3 (b) shows the packaging bag after sealing. Show. In the present embodiment, a packaging bag made of a glossy light-shielding packaging film having a metal layer and packaging a shaving manufactured by thinly cutting a knot will be described as an example.

  As shown in FIGS. 1-3, the packaging bag 10 is comprised by bonding together the 1st packaging film 11 and the 2nd packaging film 12 which are light shielding multilayer films with light-shielding property, and the 1st packaging film 11 is comprised. The front side of the bag, the second packaging film 12 is located on the back side of the bag.

  The packaging films 11 and 12 have a structure in which a sealant layer 19, a metal layer 17, a transparent layer 16, and a base material layer 13 are laminated in order from the inside of the bag, except for the ink layer and the like by printing. Is a transparent layer. In addition, sectional drawing of FIG.1 (b) and FIG.2 (b) has expanded and showed the thickness direction of the packaging films 11 and 12. FIG.

  The sealant layer 19 is located on the innermost surface in contact with the filler, and exhibits a function of being welded mainly by heat sealing. The metal layer 17 and the transparent layer 16 constitute a barrier layer 15, and the barrier layer 15 exhibits functions such as moisture proofing, waterproofing, air proofing, aroma retaining property, heat insulating property, light shielding property, and ultraviolet absorbing property. .

  In the present embodiment, the metal layer 17 has a light shielding property, whereas the transparent layer 16 is a transmissive layer that transmits light. The base material layer 13 is located on the outermost surface and functions as a film layer on which printing is mainly performed.

  In the packaging bag 10 before filling the shaving node to become the contents 30, the first packaging film 11 and the second packaging film 12 are formed along the left and right side edges in the figure, the vertical seal region 21 in the figure. In the horizontal sealing region 22 formed along the lower edge, the packaging bag (three-sided bag) 10 that has been welded in advance by heat sealing and in which only the bag opening 20 at the upper edge in the figure is opened is a shaving node. Provided to the filling section.

  The packaging bag 10 after filling the shavings 30 to be the contents 30 is sealed in a state in which the bag mouth sealing region 23 of the bag mouth 20 is welded by heat sealing, and the shavings are filled inside the packaging bag 10. Is done. Here, in the present embodiment, a seal inspection is performed to check whether foreign matter is sandwiched in the heat seal portion of the bag mouth 20 in the bag mouth seal region 23 of the second packaging film 12 located on the back side of the packaging bag 10. A transparent window 25 is formed.

  As shown in FIG. 1B and the like, the transparent window 25 is formed by removing the metal layer 17 in the region where the transparent window 25 is formed, and the barrier layer 15 in the region of the transparent window 25 is The metal layer 17 which is a light shielding layer does not exist and is formed only from the transparent layer 16. Therefore, the second wrapping film 12 is a light-shielding film that gives high gloss in areas other than the transparent window 25 without reflecting light and transmits light only through the transparent window 25.

  In addition, the metal layer 17 is formed over the whole 1st packaging film 11, and the transparent window is not formed. In the sealed packaging bag 10, the transparent window 25 portion of the second packaging film 12 is welded and integrated with the first packaging film 11 having no transparent window. Therefore, after sealing, when the portion of the transparent window 25 is viewed from the back side of the packaging bag 10, only the inner surface of the metal layer 17 of the first packaging film 11 can be seen and can be seen through to the front side of the packaging bag 10. There is no.

  Thereby, after heat sealing the bag mouth sealing region 23, the metal layer which is a light shielding layer even when the portion where the transparent window 25 is formed is viewed from either the front side or the back side of the packaging bag 10 Since 17 can be seen, it is possible to maintain a glossy and high-grade appearance in the entire packaging bag 10 and to prevent deterioration due to light irradiating the contents.

  On the other hand, when a sealing failure occurs such that a shaving node is bitten into the bag mouth seal region 23 when the bag mouth 20 is sealed, the first packaging film can be seen through the transparent window 25 when viewed from the back side of the packaging bag 10. It becomes possible to see the foreign matter pinched | interposed into the seal | sticker part between 11 and the 2nd packaging film 12 from the outside.

  Here, the size of the transparent window 25 will be described. First, since foreign matter on the seal portion may be bitten over the entire bag mouth seal region 23, the transparent window 25 also needs to be formed over substantially the entire longitudinal direction of the bag mouth seal region 23. There is.

  Further, as the width of the transparent window 25 in the short direction of the bag mouth seal region 23 is larger, it becomes easier to detect foreign matters in the seal portion. However, the transparent window 25 protrudes from the bag mouth seal region 23 in the width direction. If this happens, the content 30 becomes visible from the outside, or the content 30 is deteriorated by light irradiation, which is not desirable. Therefore, the transparent window 25 needs to be located in the bag mouth seal region 23 in the width direction.

  In addition, when the packaging bag 10 is manufactured, printing deviation and front / back bonding deviation occur to some extent. For example, in the case of a packaging bag with a cut section, a printing deviation of ± 0.3 mm and a bonding deviation of ± 0.5 to 1 mm are assumed. Therefore, since it is necessary to have a certain margin, it is desirable that the transparent window 25 be formed in a region separated from the both ends of the bag mouth seal region 23 by 0.6 mm or more in the width direction. It is desirable to form a region separated by 1.5 mm or more.

  On the other hand, if the width of the transparent window 25 is small, it cannot be recognized when a foreign object exists outside the area of the transparent window 25. Further, since the area of the transparent window 25 is narrowed, even if there is a very small foreign object, it is determined that the seal is defective, and the seal defect determination rate may be increased.

  Therefore, the width of the transparent window 25 is desirably 1 mm or more. Further, in order to secure an effective heat seal width of 3 mm or more for enhancing the sealing performance, it is desirable that the width of the transparent window 25 be 3 mm or more. In consideration of such points, in the present embodiment, the length of the bag seal region 23 in the short direction is 9 mm, whereas the transparent window 25 is formed with a width of 3 mm at the center. The margins on both sides of the transparent window 25 are 3 mm each.

  Subsequently, as the sealant layer 19, low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), linear low density polyethylene (L-LDEPE), ethylene vinyl acetate copolymer (EVA) ) And thermoplastic resins such as unstretched polypropylene (CPP).

  As the transparent layer 16, the barrier layer 15 is made of polyethylene terephthalate (PET), ethylene vinyl alcohol copolymer (EVOH), polyvinylidene chloride (PVDC), biaxially oriented polypropylene (OPP), nylon (NY), or the like. The film is formed by depositing aluminum or the like as the metal layer 17 on the film surface of the transparent layer 16 or attaching an aluminum foil or the like.

  The transparent window 25 can be formed by peeling only the region of the transparent window 25 from the metal layer 17 deposited on the surface of the transparent layer 16. Of course, the transparent window 25 may be formed by other methods such as masking during vapor deposition. Moreover, as the base material layer 13, resins such as stretched polypropylene (OPP), polyethylene terephthalate (PET), and nylon (NY) can be used.

  Next, a seal inspection method for inspecting whether heat sealing after filling the contents 30 is performed well in the packaging bag 10 described above will be described. First, the packaging bag 10 having the above-described configuration is provided as a three-sided bag making in which the vertical seal region 21 and the horizontal seal region 22 are sealed in advance, and is provided to a bagging production line for shavings.

  In the bagging production line, the packaging bag 10 is transported with the bag mouth 20 facing up, and the shaving nodes are filled into the bag by a certain amount from above with the bag mouth 20 widened. After filling the contents 30, a push rod is inserted from the bag mouth 20, and the shaving node is pushed inward so as not to stay near the bag mouth 20. Thereafter, after an inert gas injection nozzle is inserted into the packaging bag 10 and the inert gas is injected into the bag, the bag mouth seal region 23 of the packaging bag 10 is thermally welded by the heat seal member, and the packaging bag 10 Is sealed.

  The packaging bag 10 thus sealed is transported to a seal inspection place in order to inspect whether or not the heat seal is satisfactorily performed, and a seal inspection is performed by a seal inspection device. FIG. 4 is a schematic diagram schematically showing the configuration of the seal inspection apparatus according to the present embodiment. As shown in the figure, the seal inspection device 50 includes a collimate light source 51, a line sensor 52, a backlight 53, a chuck member 55, a guide member 56, and a control device 58.

  The collimated light source 51 is a light source that emits collimated light, and includes a light source such as a laser light source, a fiber light source, and an LED light source, and a lens for making the light from the light source into parallel light. In the present embodiment, the collimated light source 51 is installed at a position where the incident angle is 50 to 80 ° with respect to the surface of the bag mouth seal region 23 to be inspected.

  The line sensor 52 that is an imaging device is located at a position that is substantially perpendicular to the surface of the bag mouth seal area 23 and that faces the bag mouth seal area 23 located at the inspection location. The line sensor 52 has an imaging area set so that the vicinity of the bag mouth 20 including the bag mouth seal region 23 of the packaging bag 10 passing through the inspection place can be photographed.

  The backlight 53 has a surface light source of LED, and is located at a position facing the bag mouth seal area 23 located at the inspection place, on the opposite side of the line sensor 52 with the packaging bag 10 in between. Has been.

  The chuck member 55 and the guide member 56 are members constituting a transport device for transporting the packaging bag 10 in the production line. The chuck member 55 conveys the packaging bag 10 from the left side to the right side in the drawing in a state where both ends of the packaging bag 10 are sandwiched from both sides.

  The guide member 56 is a member for guiding the transport bag 10 to be correctly transported to the inspection place, and has two guide plates installed in parallel. The packaging bag 10 is guided between the two guide plates to the inspection place. The packaging bag 10 is conveyed while being sandwiched between the chuck members 55 such that the second packaging film 12 in which the transparent window 25 is formed is on the line sensor 52 side.

  The control device 58 is connected to the line sensor 52 and has a function of determining whether or not heat sealing is satisfactorily performed based on a captured image captured by the line sensor 52.

  In such a configuration, when the packaging bag 10 after the bag mouth seal region 23 is heat-sealed is conveyed to the inspection place, the packaging bag 10 passes through the imaging area of the line sensor 52 and the bag of the packaging bag 10. The vicinity of the mouth 20 is photographed while receiving light from the collimated light source 51 and the backlight 53.

  Since the line sensor 52 is a line camera, as the packaging bag 10 moves, images of the bag mouth seal area 23 are sequentially taken into the line sensor 52 and the captured images are sent to the control device 58. Since the light of the backlight 53 is shielded when the packaging bag 10 is conveyed, the control device 58 detects the edge of the packaging bag 10, so that the region corresponding to the bag mouth sealing region 23 including the transparent window 25. Can be recognized.

  Subsequently, the control device 58 determines a heat seal failure based on a photographed image corresponding to the bag mouth seal region 23. This determination process will be described with reference to FIGS. FIG. 5 is a schematic diagram for explaining the principle of seal inspection according to the present embodiment. FIG. 5A is a diagram showing a state when heat sealing is normally performed, and FIG. It is a figure which shows the state at the time of the seal | sticker failure by the biting of a foreign material having occurred.

  FIG. 6 is a view showing a photographed image by the line sensor according to the present embodiment, FIG. 6A is a photographed image when heat sealing is normally performed, and FIG. 6B is a foreign object bite. The photographed image at the time of the seal | sticker defect resulting from being included is shown.

  First, as shown in FIG. 5A, when heat sealing is performed well, the irradiation light from the collimating light source 51 is collimated light with little diffusion, so that the incident light irradiated to the area of the transparent window 25 is irradiated. Most of the light 60 is composed of the transparent base layer 13, the transparent layer 16, and the sealant layer 19, and is transmitted through the second packaging film 12 where the metal layer 17 is not present. The incident light 60 transmitted through the second packaging film 12 subsequently passes through the transparent base material layer 13 of the first packaging film 11 and reaches the metal layer 17.

  Since the metal layer 17 formed by aluminum deposition is a flat surface having a high reflectance such as a mirror surface, most of the incident light 60 that reaches the metal layer 17 is regularly reflected to become reflected light 61. The reflected light 61 does not reach the line sensor 52 and is not captured by the line sensor 52. Therefore, as shown in FIG. 6A, the photographed image when the heat sealing is performed well becomes dark in the entire bag mouth sealing region 23 including the area of the transparent window 25.

  On the other hand, as shown in FIG. 5B, a foreign matter is sandwiched between the first packaging film 11 and the second packaging film 12 at the time of sealing, resulting in a sealing failure. The incident light 60 from the collimated light source 51 irradiated to the area of the transparent window 25 passes through the transparent second packaging film 12 without the metal layer 17 and reaches the foreign material 31.

  The surface of the foreign material 31 such as a shaving node is a rough tissue, and the reflected light on the surface of the foreign material 31 becomes scattered light 62 that is diffusely reflected at a wide angle. For this reason, the scattered light 62 is captured by the line sensor 52, and the photographed image when a seal failure occurs due to biting is present in the area of the transparent window 25 as shown in FIG. 6B. The part to be brightened.

  Therefore, when there is a bright area of a predetermined value or more in the area of the transparent window 25, the control device 58 can determine the occurrence of a seal failure, assuming that a seal failure has occurred due to foreign matter being caught.

  In the above, the seal failure determination process due to the biting by the control device 58 has been described. However, the seal failure determination based on the photographed image of the line sensor 52 is not limited to the biting seal failure, but the seal due to generation of wrinkles in the bag mouth seal region 23. It is also possible to determine a seal failure due to a defect, skew, fold, misalignment, or the like.

  Moreover, in this embodiment, while using collimated light as a light source for a seal | sticker test | inspection, while installing the collimate light source 51 so that the incident angle to the bag mouth seal | sticker area | region 23 which is a test object may be 50-80 degrees. Since the line sensor 52 is disposed in the normal direction so as to face the surface of the bag mouth seal region 23, it is possible to perform a highly reliable defective seal determination with few determination errors.

  When the irradiation light is not collimated light but is easily diffused, or when the incident angle of the irradiation light to the bag mouth seal region 23 is small, even if there is no foreign matter 31, both the packaging films 11 and 12 Although the light reflected by the metal layer 17 reaches the line sensor 52 and becomes noise, the light reflected by the metal layer 17 is made incident by collimated light incident at a large angle of 50 ° or more as in this embodiment. Can be largely suppressed from reaching the line sensor 52.

  On the other hand, when the incident angle of the collimated light becomes larger than 80 ° and becomes parallel to the surface of the bag seal region 23, the light incident on the foreign matter from the transparent window 25 is reduced. Detection of 31 becomes difficult. Therefore, in this embodiment, the incident angle of collimated light is set to 50 ° or more and 80 ° or less.

  As mentioned above, although embodiment of this invention was described in detail, this invention is not limited to embodiment mentioned above, A various deformation | transformation is possible within the range which does not deviate from the main point of this invention. For example, it is needless to say that the contents of the packaging bag are not limited to shavings but may be other foods, medicines, plant seeds, dried plants and the like.

  Moreover, the structure and raw material of the packaging film which comprises a packaging bag can also be changed suitably. For example, when there is no need to print on the surface of the packaging bag, the base material layer may be omitted, and the light-shielding packaging film may be composed of the sealant layer and the barrier layer.

DESCRIPTION OF SYMBOLS 10 Packaging bag 11 1st packaging film 12 2nd packaging film 13 Base material layer 15 Barrier layer 16 Transparent layer 17 Metal layer 19 Sealant layer 20 Bag mouth 21 Vertical seal area 22 Horizontal seal area 23 Bag mouth seal area 25 Transparent window 30 Contents Object 31 Foreign matter 50 Seal inspection device 51 Collimated light source 52 Line sensor 53 Backlight 55 Chuck member 56 Guide member 60 Incident light 61 Reflected light 62 Scattered light

Claims (1)

And the sealant layer of transparent, a packaging bag formed by sealing the peripheral portion and the barrier layer comprising a metal layer having a light shielding property, the combined two-ply light shielding packaging film having at least, sealed after filling of the contents The bag mouth sealing region of the packaging bag in which the transparent window extending substantially over the entire length in the bag mouth sealing region and having no metal layer is formed only on one of the light shielding packaging films. In the seal inspection method for inspecting the seal failure of
An irradiation step of irradiating collimated light at an incident angle of 50 ° or more and 80 ° or less with respect to the surface of the bag mouth seal region on the side where the transparent window of the packaging bag is transferred to the inspection place after sealing,
An imaging step of sequentially photographing the bag mouth seal area including the transparent window by a line sensor installed at a position facing the bag mouth seal area of the packaging bag located at the inspection place in the vertical direction of the surface thereof. And an imaging step of taking an image while receiving light from the backlight installed on the opposite side of the line sensor across the packaging bag located at the inspection place,
Based on the photographed image photographed in the imaging step, the control device bites in the bag mouth seal region while detecting the edge of the packaging bag by the light from the backlight being shielded by the packaging bag. And a seal failure determination step for determining whether or not a seal failure has occurred.