JP2009085803A - Quality inspection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a quality inspection method capable of setting a clear standard for judging good or bad quality of a seal that can measure rapidly and easily in a short time without relying on the experience and hunch of an examiner and without permitting the judgment standard to vary depending on an examiner. <P>SOLUTION: The quality inspection method includes a step of forming a packaging layer material into a tubular shape, a step of filling a food product and a step of inspecting the quality of a container obtained by cross-sealing the packaging material in a horizontal direction, wherein the quality of an area to be inspected is determined by preparing a sample to be tested 41, pre-heating the area to be inspected in the cross-seal area 23, peeling off the pre-heated area to be tested and measuring the peeled off face by a detection means consisting of a circularly polarizing plate. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to an inspection method for inspecting the quality of a container filled with a liquid food such as juice or milk.

In paper containers filled with liquid foods such as juice and milk, a web-like packaging laminate material that has a crease line and laminates the polyolefin heat seal innermost layer is formed into a tube shape, and the longitudinal direction of the tube is vertical. Seal, fill the tube-shaped packaging material with food, seal the polyolefin-type heat seal innermost layer of the tube-shaped packaging material in the transverse direction at predetermined intervals, and cut in the middle of the transverse seal zone to make a pillow-shaped preform And the flap formed by folding along the crease line is sealed to the container side wall and the container bottom to obtain a final shaped container.

An outline of an example of the paper container filling and packaging machine is shown in FIG. In the filling machine shown in this example, the packaging material web 1 which has a thermoplastic material layer such as polyethylene as inner and outer layers and is wound in a roll shape is unwound, and the inside of the filling machine is conveyed by a roller. The strip tape 2 is joined to one end of the packaging material web by the strip tape applicator 3, the packaging material web passes through the sterilant tank 4 and sterilized, and the sterilizing agent is removed by the air knife 5. A tubular web is formed by the forming roller 6, and both ends of the packaging material are overlapped to form an overlap, and the overlap is sealed in the vertical direction of the tube by the vertical seal element 8 in the vertical line direction. The tube is filled with liquid food from the filling pipe 7. While this tube is fed downward, it is sandwiched between the sealing jaw 10 and the opposing jaw 11 and laterally sealed in the transverse direction to form two lateral sealing zones. At the same time, the pillow-shaped preforms 12 are continuously molded, and the middle of the seal band of the connected pillow-shaped preforms is cut with a knife or the like to obtain individual pillow-shaped preforms 13. The upper and lower flaps of the pillow-shaped preform that has been cut off in the final folder 15 are folded and formed into a final package filling container 14.

A mode in which the pillow-shaped preform 13 is folded at the final folder 15 is shown in FIG. The pillow-shaped preform 13 is sealed with two horizontal (horizontal line) seal zones 23 and vertical seal zones 26, and has side walls 22, 22b and 22a separated by crease lines. (See Fig. 2 (a))
As shown in FIG. 2 (b), the body portion of the pillow-shaped preform is formed in a rectangular parallelepiped shape along the crease line, and the lateral seal band 23 and the flaps 24 and 25 are formed on the end portion of the instrument wall. It is formed to stand upright. The lateral seal zone 23 stands upright from the bottom surface 22b and the top surface 22a, and the flaps 24, 25 communicate integrally with the container wall via the ridges 25a, 24a.
Next, as shown in FIG. 2 (c), after folding the transverse seal zone 23, the flap is rotated around the ridge, the container top side flap 24 is on the side wall 22, and the container bottom side flap 25 is Folded into the bottom surface 22b.

  In FIG. 3, the external appearance perspective view of a rectangular parallelepiped liquid food filling paper container is shown. The container 14 has a folded horizontal sealing zone 23, container walls 22 and 22a, a vertical sealing zone 26 extending from the top wall 22a through the back wall to the bottom, and is folded through a ridge 24a. 24.

  In the sealing zone, sufficient sealing must be performed so that the liquid food contained in the container does not leak or come into contact with the outside air. However, if the temperature and pressure of the transverse seal are not appropriate, the molten thermoplastic material of the packaging laminate material may protrude into the container filled with the contents. The molten material comes into direct contact with the liquid food or the like of the contents, becomes rapidly fragile and becomes brittle, and the laminated material may be broken from the protruding portion. At the time of sealing, the packaging laminate materials must be sufficiently bonded together.

Therefore, liquid food containers that have been commercialized with a filling and packaging machine are periodically extracted by an operator of the machine at the time of inspection, and with respect to the extracted containers, the method is substantially opposite to the final shape of the container, that is, The specimen is prepared by peeling off the flap from the instrument wall by the reverse method in which the flap is folded in the final folder of the filling and packaging machine.
Regarding the inspection of the vertical seal / horizontal seal, a method of measuring the seal width by melting unnecessary layers such as aluminum foil with hydrochloric acid, sodium hydroxide or the like is adopted. However, it takes at least one hour, and since it uses powerful drugs, it is hard to say that it is a simple method when considering use at the manufacturing site.
JP 2003-194661 A

For a container that has been extracted by an operator, a time-consuming and simple measurement is determined based on the experience and intuition of the inspector, and there is a problem in that the criteria for the determination vary depending on the inspector.
Even if measured electrically or optically, there is no clear standard for determining the quality of a seal, and a quality inspection method capable of establishing a standard value for determining the quality of a seal is required.
The purpose of the present invention is to be able to measure quickly and easily in a short time, without relying on the experience of the inspector and its intuition, and to determine the quality of the seal without the criteria of the judgment being varied by the inspector. It is to provide a quality inspection method that enables standards.

In the quality inspection method of the present invention, a web-like packaging laminate material having a predetermined crease line and laminating the polyolefin heat seal innermost layer is formed into a tube shape, the packaging material is vertically sealed in the vertical line direction, and the tube-like packaging Formed by filling food in the material, transversely sealing the packaging material at predetermined intervals, cutting in the middle of the transverse seal zone to obtain a pillow-shaped preform, and folding along the crease line A method for inspecting the quality of a container obtained by bonding a flap to a container side wall and / or a container bottom,
Peel off the flap that is adhered to the container and return it to the shape of the pillow-shaped preform,
Remove the filled food from the container to prepare the specimen,
Preheat the area to be inspected in the horizontal seal zone,
The preheated area to be inspected is peeled off, and the peeled surface is measured with a detection means comprising a circularly polarizing plate,
The quality of the inspected area is determined based on the measured value from the detecting means.

In the quality inspection method according to a preferred aspect of the present invention, the visual inspection is performed from the detection means.

In the quality inspection method according to a preferred aspect of the present invention, measurement is performed from the detection means by image processing.

In the quality inspection method according to a preferred aspect of the present invention, the inspection area is preheated by the line condensing near infrared heater.

The quality inspection method according to the present invention can measure quickly and easily in a short time, and does not rely on the inspector's experience and its intuition, and the quality of the determination is determined without the judgment standard being varied by the inspector. Enable clear standards.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
As shown in FIG. 1, the object of the quality inspection method of this embodiment is that a roll-shaped packaging material web 1 having a crease line is unwound, formed into a tube shape by a forming roller 6, and both ends of the packaging material are overlapped. An overlap is formed, and the overlap is longitudinally sealed by the vertical seal element 8 in the vertical line direction, the food is filled from the filling pipe 7 into the tube-shaped packaging material, and the tube has a length corresponding to one packaging container. While being fed only downward, it is sandwiched between the sealing jaw 10 and the opposing jaw 11 and is transversely sealed in the transverse direction to form two transverse sealing zones, and the middle of the sealing zone of the connected pillow-shaped preforms with a knife or the like Cut into individual pillow-shaped preforms 13 and fold the upper and lower flaps of the pillow-shaped preforms separated in the final folder 15 to finish. A container obtained by molding the packaging filling container 14 of the state.

FIG. 4 shows a detailed partial cross-sectional view of the horizontal sealing device. In this embodiment, the tube-shaped packaging material 1 filled with food is formed into an approximate container shape by being sandwiched between two pairs of molded flaps 41 while being sent downward by a length corresponding to one packaging container. Two pairs of sealing jaws 10 and opposing jaws 11 are sandwiched and transversely sealed in the transverse direction to form two transverse sealing zones, and the middle of the sealing zone of the connected pillow-shaped preform is cut with a knife 42. To separate individual pillow-shaped preforms 13.
As shown in FIG. 3, the obtained container is a rectangular parallelepiped liquid food-filled paper container 14. The container 14 has a folded horizontal sealing zone 23, container walls 22 and 22a, a vertical sealing zone 26 extending from the top wall 22a through the back wall to the bottom surface, and a flap 24 folded through a ridge 24a. Is provided.

In an embodiment of the present invention, the container is pre-processed by the preprocessing means in a manner substantially opposite to the final shape forming of the container in which the flap is folded at the final folder of the filling and packaging machine shown in FIG. The flap sealed on the container wall is rotated around the edge that communicates integrally with the container wall, and is peeled off from the container wall to return to the shape of the pillow-shaped preform.

Next, the container wall is cut entirely or partially by cutting means to take out the filled food, and the pillow-shaped preform is formed into a plate shape. As shown in FIG. 5, the lateral side portion of the plate-shaped preform is cut and the center of the one-sided container wall 22 is cut in the transverse direction. With the preparation means, the cut container is developed into a substantially flat shape or a predetermined shape. 61 specimens as shown in FIG. 6 are prepared.

In the embodiment of the present invention, the inspection area of the lateral seal zone 23 is preheated.
FIG. 7 shows a mode in which the horizontal seal zone 23 of the subject 41 is preheated from above by the line condensing near infrared heater 71. The focal length of the heater 71 is adjusted according to the seal width of the horizontal seal zone 23 of the subject 41. The seal surface of the horizontal seal 23 of the subject 41 is uniformly heated by the heater 71.
If necessary, the horizontal seal zone 23 of the subject 41 can be preheated from below by another line condensing near infrared heater 72 from below.

A subject 41 as shown in FIG. 7 is held by a roller and a holding device. Furthermore, as shown in FIG. 7, the horizontal seal zone 23 is slowly peeled off in the direction of the arrow while being heated in a short time with a line condensing heater. That is, peel off while applying a load

The near-infrared heater used in this embodiment energizes a coiled metal filament made of tungsten or the like enclosed with a gas in a quartz tube or the like, and heats this part to a high temperature of about 2000 ° C. to generate near-infrared rays emitted from the incandescent state. Use through a quartz tube. Unlike the far infrared ray, the near infrared ray is absorbed deeper than the far infrared ray in the absorption inside the object.

In the quality inspection method according to a preferred aspect of the present invention, the amount of preheating is adjusted.
The output of the heater 71 is adjusted, and in one reference example, the sealed portion of the subject is not broken by hand immediately after heating, and the resin in the sealed portion is peeled off without any trouble. The output of the heater 71 is adjusted by the wattage and the heating time.

In the quality inspection method according to a preferred aspect of the present invention, the preheated area to be inspected is measured by the detection means.
In this aspect of the quality inspection method, the preheated area to be inspected is peeled off, and the peeled surface is measured by a detecting means comprising a circularly polarizing plate, and the quality of the inspected area is determined based on the measurement value from the detecting means. judge.
When the horizontal seal zone 23 is slowly peeled off in the direction of the arrow while heating with a line-condensing heater in a short period of time, the sealed portion is peeled off under load (stress). Load history remains compared to the unsealed part.

This load history can be confirmed through the polarizing plate. In particular, when observed using a circularly polarizing plate, the seal width can be remarkably confirmed as shown in FIG. When the horizontal seal width is viewed through the circularly polarizing plate, it can be confirmed as a line with clear contrast as shown by the two arrow lines in FIG.
Circularly polarized light is a polarized light having an angular momentum that draws a circle as the vibration of the electric field (and magnetic field) propagates, and has a right circular polarization and a left circular polarization depending on the rotation direction.
In order to easily obtain circularly polarized light, a circularly polarizing plate is used, and the circularly polarizing plate is obtained by superimposing a polarizing plate and a quarter wavelength plate with their main axes shifted by 45 degrees. When non-polarized light enters the circularly polarizing plate, only the linearly polarized light component is extracted by the polarizing plate and converted to circularly polarized light by the wave plate.

Since the horizontal seal width can be confirmed as a clear line through the circularly polarizing plate, the seal width (mm) can be automatically measured easily using an image processing apparatus.
In a quality inspection method according to a preferred aspect, measurement is performed from the detection means by image processing.
In the image processing for extracting some information from the image, a target image is input, a conversion process is performed on this image, and as a typical method of this conversion, “binarization” that converts a grayscale image into a binary image, There is “edge detection” that finds the boundary of the object from the density change, and then necessary information is extracted, and finally obtained information is classified.

In another aspect of the quality inspection method, measurement is performed from the detection means by visual observation.
For example, it is possible to very easily visually inspect whether the seal width is within the range by drawing a line of the seal width upper limit value, ideal value, and lower limit value on the circularly polarizing plate and using this as a template.

In the quality inspection method according to a preferred aspect of the present invention, the distinction between good seal and bad seal appears clearly. This is because a peeling phenomenon occurs on the seal surface of the defective seal portion by preheating the subject. Further, it is considered that the difference in electrical characteristics was amplified in order to reheat the specimen whose dielectric constant (loss coefficient) has changed because the recrystallized state after sealing is different.

As demonstrated in the above-described aspect, depending on the level of automation, the time required for the inspection is about 1 to 3 minutes, and the measurement time can be greatly reduced. Note that the heat peeling operation takes about 5 seconds.
Furthermore, quantitative judgment, that is, objective judgment can be made, and inspection independent of the skill of the inspector can be realized.
It can be safely inspected without using chemicals.

In addition, this invention is not limited to the said embodiment, It can change variously based on the meaning of this invention, and does not exclude them from the scope of the present invention.

The quality inspection method of this invention can be used for manufacturing packaging containers for beverages such as milk, juice and mineral water, and liquid foods.

The conceptual diagram which shows one form of the packaging filling machine which can be used for the Example of this invention. Schematic showing the final shape forming process of a container that can be used in an embodiment of the present invention The perspective view of the container which can be used for the Example of this invention Sectional drawing which shows horizontal seal formation of the packaging filling machine which can be used for the Example of this invention The perspective view which shows the subject from the container which can be used for the Example of this invention Plan view of a subject that can be used in an embodiment of the present invention The conceptual diagram which shows the preheating in the Example of this invention The plane photograph which observed the horizontal seal width through the circularly-polarizing plate in one Example of this invention.

Explanation of symbols

23 Horizontal seal band 41 Subject

Claims (4)

A web-like packaging laminate material that has a predetermined crease line and laminates the polyolefin heat seal innermost layer is formed into a tube shape, the packaging material is longitudinally sealed in the vertical direction, and the tubular packaging material is filled with food. The packaging material is transversely sealed in a transverse direction at predetermined intervals, cut in the middle of the transverse seal zone to obtain a pillow-shaped preform, and a flap formed by folding along the crease line is a container side wall. And / or a method for inspecting the quality of a container obtained by bonding to the bottom of the container,
Peel off the flap adhered to the container, return to the shape of the pillow-shaped preform,
Remove the filled food from the container to prepare the specimen,
Preheat the inspected area of the transverse seal zone;
The preheated area to be inspected is peeled off, and the peeled surface is measured with a detection means comprising a circularly polarizing plate,
A quality inspection method comprising: determining whether the inspected area is good based on a measurement value from the detection means. The quality inspection method according to claim 1, wherein the quality is measured from the detection means by visual observation. The quality inspection method according to claim 1, wherein measurement is performed from the detection means by image processing. The quality inspection method of Claim 1 which preheats this to-be-inspected area | region with a line condensing type near-infrared heater.