JP3517079B2 - Non-contact inspection method of high frequency aluminum seal - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact inspection method for high-frequency aluminum seals, and more particularly, when a container inner lid made of at least an aluminum foil and a synthetic resin molding member is sealed with an aluminum foil by high-frequency induction heating. The present invention relates to a non-contact inspection method for a high-frequency aluminum seal, in which the quality of the seal is judged directly from an infrared thermal image obtained from the upper surface of the outer lid or from a histogram obtained by data processing such an infrared thermal image.

[0002]

2. Description of the Related Art Conventionally, as an inspection method using infrared rays, for example, Japanese Patent Laid-Open No. 62-28650 "Inspection method for presence / absence of foreign matter" and Japanese Patent Application Laid-Open No. 7-101423 "Packing container adhesion inspection device" are known. . More specifically, the former is a blister of food by measuring the temperature difference caused by the heat change from the outside to the inspection object and the difference in the heat capacity of the foreign matter adhering portion of the inspection object from the other parts with the infrared detector. The indirect automatic determination of the adhesion of the filler to the inner surface of the container top lid of the packaged product, and the latter is the infrared rays emitted from the upper surface and both side surfaces of the packaging container having the hot melt adhesive site. By detecting with a radiation thermometer, it is possible to inspect non-contact from the outside of the packaging container for the adhesion failure of the adhesion part of the packaging container. Although these are common to the present invention in that they use an infrared thermal image, the object of the inspection (inspection location) and the difference in the infrared rays (source) to be captured, etc. It is completely different from the invention.

Liquid, powdery or granular seasonings such as mayonnaise, dressing, tomato ketchup, soy sauce and sauce have a large volume of up to 1 kg or more and a small volume of 10.
Resin container (bottle) made of non-metallic material with a small capacity of 0 g or less
The container opening is placed in a circulation state in which it is covered with a screw-type resin cap (outer lid) made of the same non-metallic material. It is desired that these products have an inner lid in the distribution process from the viewpoint of safety and the hygiene of consumers.

As such an inner lid, there is a sealing method by heating a high frequency induction aluminum foil. That is,
For example, an aluminum foil laminated with a heat-fusible resin film such as a polyethylene film through an adhesive layer (hereinafter also referred to as an aluminum seal laminated material) may be used as a donut-shaped upper edge of the opening of a container filled with contents. A circular shape that is slightly larger than the outer diameter of the upper edge of the donut shape (preferably, a tab is attached so that it can be easily removed when opening the lid later when opening) to cover it, and this cut piece is a heat-fusible resin film The container opening with the surface of the container facing downward, and from above (preferably, a donut-shaped ridge is provided on the inner bottom so that the aluminum foil can be pressed well against the upper edge of the container opening).
Screw the resin outer lid (cap) and pass the high frequency induction heating sealer in this state. FIG. 1 shows a conceptual diagram of the relationship between each part.

Thus, when passing through the high-frequency sealer,
Eddy current flows inside the outer edge of the circular cut piece of aluminum foil, and the aluminum foil is heated by this eddy current.
The cut piece of aluminum foil (aluminum seal) is pressed against the donut-shaped upper edge of the bottle (container) opening by the outer lid (cap) (the ridge provided on the inner bottom of the outer lid).
The heat generated by the aluminum seal melts the resin in the bottle in the portion where the aluminum seal is in contact (portion A in FIG. 2),
Later, the resin that has melted solidifies due to natural cooling. by this,
An aluminum seal (inner lid) is bonded to the bottle opening, and the outer lid is tightened to complete the product.

However, the high-frequency induction heating sealing performed in this manner is not always performed satisfactorily, and the cap (upper lid) is loose, the diagonal cap and the aluminum seal are overlapped, and the heating temperature is too low. An incomplete defective seal may occur due to the reason that the heating temperature is too high, the contents (contents) are attached to the seal portion, the seal surface is notched, or the aluminum seal is not present.

Therefore, for example, by using a belt conveyor, the contents (contents) are filled in a resin container, and a circular inner lid made of aluminum foil is placed on the donut-shaped upper edge of the container opening,
This is pressed against the upper edge of the container opening with a screw-in type outer lid (cap), and is subjected to high-frequency induction heating in this state to fuse the aluminum foil to the upper edge of the container opening by high-frequency heating. It is strongly possible to easily detect products with imperfect seals as described above on a production line that continuously manufactures products with tight stoppers, and to eliminate such products (defective products). Is desired.

[0008]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a method for simply detecting a defect in a high frequency aluminum seal as described above in the background of the prior art described in the preceding paragraph. .

[0009]

Means for Solving the Problems As a result of earnest research to achieve the object described in the preceding paragraph, the present inventor has a lid (outer lid) in which a donut-shaped upper edge of a resin container opening has an aluminum seal inner lid.
It was attached to the aluminum seal foil part when passing through under the high frequency sealer and non-contact heating the aluminum seal laminated material and fusing the lower layer of the heat-fusible resin to the donut shape upper edge of the container mouth part. Heat is transferred to the outer surface of the donut-shaped melted portion, that is, the sealing state through the outer lid, but the state of heat conduction is captured by an infrared camera as a thermal image of infrared rays in a non-contact manner, and this is taken by an image inspection processing device. The temperature distribution on the outer surface of the top lid was reproduced in color, and it was found that it was possible to easily determine whether or not the aluminum seal was adhered in a good condition from this shape and the analyzed data, and the present invention was completed based on such knowledge. Came to do.

That is, according to the present invention, at least the synthetic resin molding member is placed on the upper edge of the donut shape of the opening of the resin container, and the inner lid of the metal piece such as aluminum foil is placed on the upper portion, and this is made into a screw type resin outer lid. Pressed against the upper edge of the container opening, and in this state, subjected to high-frequency induction heating to generate heat of the metal piece, so that the synthetic resin molding member pressed against the lower surface is partially melted to form a donut-shaped upper edge of the container opening. When heat fusion is performed, the upper surface of the cap is photographed with an infrared thermal image camera following the high frequency induction heating process, and the quality of the aluminum seal is determined based on the shape and / or data analysis of the obtained infrared thermal image. This is a non-contact inspection method for high frequency aluminum seals.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

A synthetic resin molding member and an inner lid of a metal piece (aluminum seal laminated material) such as aluminum foil on the synthetic resin molding member are placed on the upper edge of the doughnut-shaped opening of the resin container, and the screw-type resin outer lid ( Cap) to press-contact the upper edge of the container opening, subject to high-frequency induction heating in this state, and subject the synthetic resin molding member located on the lower surface of the aluminum foil to high-frequency heating fusion bonding to the upper edge of the container opening. The method itself can be appropriately determined by a conventional method.

The surface of the object is photographed by an infrared thermal image camera, and the obtained thermal image is data-processed to display the temperature distribution on the surface of the object, for example, in color (high temperature part is red, low temperature part is blue, and Displaying with a histogram in the middle part (yellow, etc.) or with a histogram can use a commercially available infrared camera, data processing, display, etc. as appropriate (for example, NEC Corporation infrared radiation). Thermometer "Thermotracer", Mitsubishi Electric Corp. high-speed thermal image analyzer "Mitsubishi Thermal Imager", Japan Avionics Co., Ltd. infrared thermal imager (TVS series),
JEOL Ltd. infrared temperature analyzer "Thermoviewer"
(JTG-6000 series), etc.).

As the high frequency oscillator used in the present invention, a commercially available device can be used. For example, "High-frequency oscillator SST-20" manufactured by Shimada Rika Co., Ltd. is preferably used.

The feature of the present invention is that the heat generated in the metal piece (aluminum foil) by the high frequency oscillation melts a part of the synthetic resin molding member laminated on the lower surface of the metal piece, and the donut shape of the mouth of the resin container is formed. The heat generated when the upper edge is sealed is transferred to the outer top surface of the outer lid through the back surface of the outer lid, the heat distribution is captured from the top with an infrared thermal image camera, and the infrared thermal image data obtained is processed. The temperature distribution on the outer upper surface of the outer lid is displayed in color, or the histogram is analyzed (by the way,
It is well known that these display by data processing can be performed in real time.) Based on these displays or analysis, if they match with those in the case of a well sealed product, a good seal is obtained. If there is no match, it is judged that the seal is defective, and the reference data is set to detect an abnormal value to inspect the seal property in a non-contact manner.

This will be described more specifically with reference to FIG. FIG. 2 shows heat conduction to the upper surface of the cap (outer lid) when the aluminum seal is heated and a histograph captured by an infrared thermal image camera from the top toward the cap. The heat generated by the aluminum seal is also transmitted to the cap portion (portion A in FIG. 2), and it can be seen from the upper part of the cap that the temperature of the donut-shaped portion is higher than the temperature inside the donut. The adhesiveness of the sealing properties can be determined fairly accurately in the form of temperature distribution.

In other words, when a clean donut shape as shown in FIG. 2 is observed (however, when the inner lid of the aluminum foil has a tab, the outer edge of the donut-shaped image is slightly chipped due to it. If it can be judged that a good aluminum seal has been applied, and other shapes are observed, (1) the cap (outer lid) is not sufficiently tightened depending on the shape, and the aluminum seal (inner lid) ) Was not pressed well against the upper edge of the donut shape of the bottle (container) opening, (2) There was a part where the aluminum seal floated due to the diagonal cap tightening, so (3) Bottle (above the donut shape of the opening) (4) The temperature did not rise sufficiently because the aluminum seal adhesive surface of the edge was not flat and did not contact the aluminum seal properly. (4) The contents adhered to the aluminum seal adhesive surface. Therefore, (5) because the output of the high frequency sealer was too large and the temperature rose too much, (6) because the output of the high frequency sealer was too small and the temperature did not rise sufficiently, (7) because there was no heating by the high frequency sealer , (8) Since the aluminum seal was not attached,
(9) Since the aluminum seals are mounted so as to overlap each other, it is possible to infer various causes of problems such as. Therefore, by using this result, it is possible to inspect all of the bottles (containers) filled with the contents flowing on the conveyor on-line for the quality judgment of the adhesion of the aluminum seal.

Although the shape of the donut is circular in the mouth of the resin container, when the present invention is carried out in the actual production process, the donut appears as an ellipse on the screen. This is because the heat-sealing of the resin container is performed on a belt conveyor that operates. That is, since the resin container is constantly moving at a constant speed, it appears on the screen as an elliptical donut having a shape crushed in the moving direction. However, even this elliptical image does not hinder analysis or visual judgment.

The quality of the aluminum seal can be determined based on the histogram obtained by the data processing of the infrared image. Similarly, the histogram when the seal is good and the histogram of the inspection object are compared, and the degree of coincidence between the two The quality of the seal is judged by whether or not to do it.

For removing a product (defective product) determined to have a defective seal (defective product) from the manufacturing line of the belt conveyor because the image or histogram does not match the image or histogram of the product (good product) which is well sealed. Is monitoring the image on the display and if a defective seal image appears, or if the above verification is performed mechanically and automatically, and if it is a defective product, No Good is displayed on the display. When Good is displayed, the defective product can be manually removed from the line, but it is also possible to convert the verification result mechanically and automatically into a drive signal for the defective product removing device. It is also possible to automatically exclude defective products.

On the other hand, in the temperature distribution data analysis of the image displayed on the screen, 1) (abnormal high temperature) detection of a high temperature value above a certain level among all measured temperatures, 2) (abnormal shape of seal part) ) Detection of the donut shape of the synthetic resin molded member welded to the upper edge of the donut shape of the opening of the resin container by detecting the ratio of the major axis and uniaxial length of the donut shape or the shape abnormality, 3) (seal temperature distribution) resin container Thermally welded part formed on the upper edge of the donut shape of the opening Detecting the temperature distribution of the center line in the flow direction of the resin container of the donut shape, 4) (Rate of seal temperature change) On the upper edge of the donut shape of the resin container It is possible to use at least one of the temperature distribution detection of the doughnut-shaped center line of the doughnut-shaped of the welded synthetic resin molding member, or to use a plurality of them in combination.

The above 1): (abnormally high temperature) Among the measured total temperatures, the standard for detecting a high temperature value above a certain level is determined by the combination of the material of the resin container and the synthetic resin forming member used for the aluminum seal member. To be done. Generally, when high density polyethylene is used for the synthetic resin forming member,
Each melting point varies depending on the manufacturer, but is generally 120
~ 140 ℃, 107 ~ 120 ℃, so the maximum temperature is 1
40 ° C. On the other hand, the heat generated by the heating by the high frequency oscillation is transferred from the top surface inside the cap to the top surface outside the cap.
Since the infrared thermal imaging camera measures the temperature of the upper surface of the cap, the melting temperature will be measured through heat conduction to the cap. Therefore, the measured temperature is much lower than the melting temperature. Actually, how much the apparent temperature outside the cap is detected to be lower than the melting temperature depends on the cap material, structure, and high-frequency aluminum sealing conditions (room temperature, high-frequency oscillation time, resin container moving speed, etc.). Therefore, it is necessary to consider and decide how often the abnormal high temperature value is set.

The above 2): (Abnormal shape of seal portion) Ratio of the major axis and the uniaxial length of the donut shape of the synthetic resin molding member welded to the upper edge of the donut shape of the resin container opening, or the shape abnormality. The detection by will be described more specifically. Since the resin container placed on the hakama is moving on the belt conveyor, the image displayed on the infrared image analysis CRT screen for detecting the sealing property is the moving direction X axis which is perpendicular to the moving direction.
Shorter than the shaft. Therefore, it is possible to perform an inspection in which the X / Y ratio is set within a certain range or the upper and lower limits of the X and Y values are set.

The above 3): (Seal temperature distribution) The heat-welded portion formed on the upper edge of the doughnut-shaped resin container opening. The temperature distribution of the center line in the flow direction of the doughnut-shaped resin container is detected as a donut shape. Since the temperature distribution differs between the meat part and the hollow part, if the temperature distribution of the center line in the flow direction of the resin container is plotted on the horizontal axis and the vertical axis is frequency, a curve with two maximum values is obtained. It can be detected by storing the pattern in the memory and comparing it with the measured value.

4) above: (Rate of change in seal temperature) The temperature distribution of the donut-shaped center line of the donut shape of the synthetic resin molding member welded to the upper edge of the donut shape of the resin container opening is mainly detected by the donut shape. This is convenient for detecting disconnection, that is, a broken portion that is not heat-welded. On the CRT screen, the X-axis is 0 to 360 degrees along the donut-shaped center line, and the Y-axis records the temperature. If the curve shows a straight line parallel to the X axis or a gentle curve, it can be considered that there is no abrupt temperature change (break zone).

An example of the inspection system according to the present invention is shown in FIG.

When the conveyor moves fast and the line speed (bottle / minute) is high, it is advisable to employ the high-speed thermal image analysis device that can well catch the temperature distribution on the upper surface of the upper lid described above even at such speed. Needless to say.

Further, when the moving speed of the conveyor is high and the moving speed of the container is high, the front surface of the container lid in the traveling direction is cooled, and the infrared thermal image obtained as a result does not have a clean donut shape even when the seal is good. Needless to say, it is possible to judge the quality of the seal by comparing the thermal image of the good seal with the thermal image of the inspection target product.

[0029]

EXAMPLES The present invention will be further described below with reference to examples.

(Preparation and installation of resin container and high-frequency sealing member) Aluminum seal laminated material (total thickness) in which synthetic resin molding member / adhesive / aluminum foil / cellophane thin film is laminated on the donut-shaped upper edge of the resin container opening. 30 μm)
Was used as an inner lid, and this was wrapped around the upper edge of the container opening portion with a screw-type red resin outer lid and pressed with a torque of 7.5 kg / cm to obtain a test sample. Resin container has a capacity of 250
5000 containers each containing g, 400 g, 600 g, and 1000 g and filled with mayonnaise were prepared. Other resin lids were prepared in yellow, orange and white.

(High-frequency seal and photographing of the sealed state) The prepared resin container was placed on a hakama for stabilizing it on a belt conveyor, moved at 530 cm / s, and a high-frequency oscillator (Shimada Rika Co., Ltd.) was used. Manufactured "SST-20") was moved in the water direction while maintaining a fixed position under the coil. In this state, the output of 89 to 106 V and 55 to 75 A was applied to the high frequency induction heating, and the heat generated from the aluminum foil partially melted the synthetic resin molding member pressed against the lower surface to heat the upper edge of the donut shape of the container opening. Fused. Following the high-frequency induction heating treatment, the upper surface of the cap was photographed with an infrared thermal image camera, and a donut-shaped temperature distribution image was displayed on the obtained TV screen.

(Analysis items) 1) (Abnormally high temperature) Detection of a high temperature value above a certain level among all measured temperatures, 2) (Abnormal shape of seal part) Welded to the donut shape upper edge of the resin container opening Of a synthetic resin molded member by detecting the ratio of the donut-shaped long axis and the uniaxial length of the molded article, or the shape abnormality, 3) (seal temperature distribution) The heat-welded portion formed on the upper edge of the donut shape of the resin container opening. Detecting the temperature distribution of the center line of the doughnut-shaped resin container in the flow direction, 4) (Rate of change in seal temperature) Donut-shaped center of the donut-shaped synthetic resin molded member welded to the upper edge of the donut-shaped opening of the resin container The temperature distribution detection of the line was performed simultaneously with 1) to 4).

(Analysis result) It was possible to visualize a donut-shaped temperature distribution colorfully with the naked eye from the image on the CRT screen. This made it possible to make an instant judgment with the naked eye.
In order to further improve accuracy, the above analysis items were detected for all samples and data were stored. In the actual process analysis, when an abnormal value is detected in the light of the above analysis items, the data stored in the computer is extracted from the sample, the cause of the abnormality is analyzed, and the subsequent measures can be taken immediately. Analysis item 1): The example detected at an abnormally high temperature was detected when high frequency sealing was performed and then high frequency sealing was intentionally performed again. An abnormal high temperature was detected in a state where part of the aluminum foil and part of the upper edge of the mouth of the resin container were loosened, and there was partial point contact due to the cap or diagonal cap. Analysis item 2): The abnormal shape of the seal part is an abnormality in the feeding speed and moving speed of the resin container. Analysis item 3):
From the (seal temperature distribution), an abnormal low temperature was detected when the aluminum seal laminated material was not set and when the aluminum seal laminated material was double set. Analysis item 4): (Rate of change in seal temperature) was detected when a part of the seal portion was not sealed.

[0034]

According to the present invention, a resin container (bottle)
Fill the contents with aluminum seal laminated material (inner lid) in contact with the top surface of the outer lid and attach it to it, let it pass under the output of the high-frequency sealer, and the synthetic resin forming member under the aluminum seal laminated material and the container. When the fusion seal is fused to the upper edge of the opening, the quality of the fusion seal can be easily and completely checked, and the quality control can be performed very efficiently and effectively.

[Brief description of drawings]

FIG. 1 is a cutaway view showing a seal portion of a high frequency seal of the present invention.

FIG. 2 shows heat conduction to the upper surface of a cap (outer lid) when heating an aluminum seal and its infrared image histogram.

FIG. 3 shows an example of an inspection system according to the present invention.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shu Zhou Arahari 2-12-1, Shimonoge, Takatsu-ku, Kawasaki-shi, Kanagawa Knorr Foods Co., Ltd. (72) Takeo Kumada 2-12- Shigenoge, Takatsu-ku, Kawasaki-shi, Kanagawa 1 Knorr Foods Co., Ltd. (72) Inventor Masao Ichiki 1-1, Suzuki-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Inside Ajinomoto Co., Inc., Production Technology Laboratory (56) Reference: JP-A-62-28650 (JP, A) JP-A-7-101423 (JP, A) JP-A-4-19139 (JP, A) JP-A-8-11922 (JP, A) JP-A-7-137059 (JP, A) Actual development Sho-62-69440 (JP, U) Actual Kaihei 7-44197 (JP, U) Japanese Patent Sho 50-12358 (JP, B1) Japanese Public Sho 58-44555 (JP, B2) Japanese Sho 53-2350 (JP, B2) Japanese Public Sho 52-47352 (JP, B2) Special Public Sho 57 46021 (JP, B2) Japanese Patent Publication Sho 53-20863 (JP, B2) Japanese Patent Publication 2-16993 (JP, B2) Japanese Patent Publication 7-64357 (JP, B2) Patent 2629530 (JP, B2) (58) Survey Fields (Int.Cl. ⁷ , DB name) G01N 25/00-25/72 B65D 35/44-35/54 B65D 39/00-55/16 JISST file (JOIS)

Claims (2)

(57) [Claims] 1. A donut-shaped upper edge of a resin container opening, at least a synthetic resin molding member, and an inner lid of a metal piece such as aluminum foil placed on the synthetic resin molding member, which is opened by a screw-type resin outer lid. The upper surface of the container is pressure-welded, and in this state, it is subjected to high-frequency induction heating, and the heat generated by the metal piece causes the synthetic resin molding member pressed to the lower surface to partially melt and heat-bond to the upper edge of the container opening donut shape. In this case, following the high-frequency induction heating treatment, the cap upper surface is photographed with an infrared thermal image camera, and the quality of the aluminum seal is determined based on the shape and / or data analysis of the infrared thermal image obtained. A non-contact inspection method for high-frequency aluminum seals. 2. The high-frequency aluminum seal non-contact according to claim 1, wherein the inner lid is at least a synthetic resin molded member and a metal piece such as an aluminum foil adhered on the synthetic resin member with an adhesive. Inspection method.