JPH05264488A - Method and device for detecting thermal welding state of film - Google Patents

Abstract

PURPOSE:To improve accuracy in judgment by positioning a polarizing plate near a detection part and then observing a discolored part and a non-discolored one within the detection part through the polarizing plate for judging the ratio value of each area. CONSTITUTION:When a paper material 1 where polyethylene film 2 is thermally welded is moved and an eye marker 5 is detected by a photo sensor 18 for synchronization output, traveling of the paper material 1 is stopped by a control unit and the thermally welded state is observed by a detection device 10. When thermal welding is performed properly. observation of an opening 4a through a polarizing plate 16 allows the opening to be observed as a same tint as other parts. Otherwise, it is observed to be different. The result is input to the control unit and an area ratio of the discolored part to the non-discolored part at the thermally welded region of the opening 4a is obtained. When the ratio is smaller than a specified value, it is judged to be proper and the line operation continues. When the ratio is larger than a specified value, it is judged that the polyethylene film is not thermally welded properly, thus stopping the machine automatically.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to whether or not a synthetic resin film is properly heat-welded to a metal coating layer (the surface coated with a synthetic resin film) of a paper material used for a beverage container or the like. The present invention relates to a method and apparatus for detecting a heat-welded state of a film.

[0002]

2. Description of the Related Art A paper material constituting a beverage container is constructed, for example, by coating a metal coating layer obtained by coating paper with a metal and further coating a synthetic resin film such as polyethylene. Here, so-called "liquid leakage" in which the beverage as the content leaks out may occur due to various causes such as the presence of pinholes in the paper material. In order to detect this liquid leak at an early stage and take necessary measures, the applicant of the present invention has recently filed Japanese Patent Application No. 3-2.
No. 74110, a liquid leakage inspection device is provided.

This liquid leakage inspection device utilizes the fact that the beverage is an electrolyte solution and therefore has conductivity.
In the case where liquid leakage occurs, the leaked beverage is configured so that electrodes adjacent to each other are brought into conduction and an electric current flows.

[0004]

As a result of continuing research, the applicant has found that most of the liquid leakage is caused by poor sealing of the opening formed as the mouth of the beverage container. discovered. Here, the sealing of the drinking mouth or the like of the beverage container is performed by heat-sealing a synthetic resin film on the opening which is the drinking mouth. Therefore, most of the cause of liquid leakage is that the synthetic resin film is properly applied to the surface of the paper material (more specifically, the synthetic resin film covered with the metal coating layer of the paper material) used for the beverage container or the like. It is not heat welded. In other words, it is extremely easy to detect liquid leakage by determining whether or not the synthetic resin film is properly heat-welded to the paper material used for beverage containers, etc., especially the opening formed as a drinking mouth. It is very convenient because it will be held at.

However, in the prior art, it is necessary to determine whether or not the synthetic resin film is properly heat-welded on the surface of the paper material, because a very large-scale equipment is required and the operation is complicated. There is the problem that a great deal of effort must be spent. For this reason, the cost becomes enormous and the economical efficiency is extremely deteriorated.

The present invention has been proposed in view of the above-mentioned problems of the prior art, and can easily and accurately determine whether or not the synthetic resin film is properly heat-welded to the surface of the paper material as described above. An object of the present invention is to provide a method and an apparatus for detecting a heat-welded state of a film that can be judged.

[0007]

A method for detecting the heat-welded state of a film of the present invention is a method for detecting the heat-welded state of a film, which comprises determining whether or not a synthetic resin film is properly heat-welded. Positioning a polarizing plate in the vicinity of the detection location to detect the welding state, observing the discolored location and the non-discolored location in the detection location through the polarizing plate, the discolored location with respect to the area of the non-discolored location Judge whether the area ratio is larger or smaller than a predetermined value, and if the area ratio of the discolored portion is larger than a predetermined value, it is determined that the synthetic resin film is not properly heat-welded, while If the area ratio is smaller than a predetermined value, it is determined that the area is properly heat-welded.

Here, the polarizing plate refers to one having a function of observing polarized light on an adhesive surface, such as a plate processed with glass, synthetic resin, liquid crystal or the like (a liquid having a polarization property) as a component.

In carrying out the present invention, the steps of arranging the above-mentioned polarizing plate, the step of observing the discolored portion and the non-discolored portion, and the determination step may be performed manually by an operator. It may be done automatically by.

Further, the film heat-welding state detecting device of the present invention detects the heat-welding state in the film heat-welding state detecting device for judging whether or not the synthetic resin film is properly heat-welded. Measurement of observing a color-changed part and a non-color-changed part in the detection part and measuring the area of the non-color-changed part and the area of the color-changed part, which is located in the vicinity of the detection part to be detected Means, it is determined that the synthetic resin film is not properly heat-welded when the area ratio of the discolored portion is larger than a predetermined value, while it is appropriate when the area ratio is smaller than the predetermined value. And a determining means for determining that they are heat-welded.

Here, a known sensor may be used as the measuring means, or an operator may work as the measuring means. Similarly, various types of control devices such as a CPU may be used as the determination means, or an operator may be used as the determination means.

In carrying out the present invention, the synthetic resin coated on the surface of the paper material and the synthetic resin to be heat-welded need not be the same material. It is only necessary that they are heat-welded.

When observing the discolored part and the non-discolored part in the detection part, it is possible to use, for example, a fiberscope.

The method and apparatus for detecting the heat-welded state of the film of the present invention are preferably combined with the automatic sorting apparatus described in JP-A-1-115484.

[0015]

According to the method and apparatus for detecting the heat-welded state of the film of the present invention having the above-mentioned structure, the polarizing plate is placed in the vicinity of the detection position where the heat-welded state is to be detected, When the detection location is observed through the plate, the detection location is observed as the same color as the other areas when the thermal welding is performed well, while the detection location is observed when the thermal welding is defective. Is observed in a different color from the rest.

Therefore, by observing the discolored spots and the non-discolored spots in the detection spot, that is, the heat-sealed region, and obtaining the ratio of the area of the discolored spot to the area of the non-discolored spot, it can be determined whether the heat-welding was successful. Is determined. That is,
If the area ratio of the discolored portion is larger than the predetermined value, it is determined that the synthetic resin film is not properly heat-welded, while if the area ratio is smaller than the predetermined value, proper heat-welding is performed. It is determined that it has been done.

Here, there are the following two cases where the heat welding is not performed properly. The first is the case where the heat welding is lost due to the thermal denaturation of the film or the object to be welded because the elapsed time of the heat welding is long or the temperature has risen too much. The second is a case where the transparent film tape is not welded, a distance is formed between the transparent film tape and the object to be welded, and a discolored portion appears largely. In either case, the area of the discolored portion is large, or the ratio of the area of the discolored portion to the area of the non-discolored portion is large.

According to the present invention, the determination as to whether or not the thermal welding has been performed satisfactorily is carried out by the above-mentioned polarizing plate, means for positioning the polarizing plate in the vicinity of the detection location, the measuring means, and the judging means. Since it can be carried out only by preparing, it does not require a large-scale facility like the conventional one. When making a distinction, the polarizing plate is positioned, and the discolored and non-discolored spots in the detection spot are observed through the polarizing plate, and whether heat welding is appropriate according to the ratio of the area of the discolored spot to the area of the non-discolored spot. This is an extremely simple work of determining whether or not there is no need for a complicated process as in the past. As a result, the labor required for determining the suitability of heat welding is significantly reduced. It is also possible to perform such work manually by a worker.

[0019]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an outline of the present invention. A paper material 1 traveling in the direction of arrow M is a member which is a raw material for a beverage container, and has a metal coating layer and a polyethylene film coating layer on its surface. is doing. Then, a polyethylene film (synthetic resin film) 2 is heat-welded to the paper material 1 by the heat seal portion 3. Here paper material 1
., Which are drinking holes, are perforated, and timing eye marks 5 ... Are provided on the right edge of the paper material 1 in the figure. Instead of providing the eye marks 5, ..., Means (not shown) for generating a timing clock or clock pulse may be provided.

The polyethylene film 2 is stored in the reel 6, is arranged so as to cover the opening 4 via the rollers 7 and 8, and is heat-welded in the heat seal portion 3.

The heat-welding state detecting device 10 of the present invention is provided on the downstream side (above the heat-sealing part 3 in FIG. 1) in the traveling direction M of the heat-sealing part 3. here,
The opening (detection location) where the thermal welding state is detected by the detection device 10 is represented by reference numeral 4a. The edge portion of the opening 4a, which is indicated by hatching in FIG. 1, is the heat seal portion 9 for which the detection device 10 determines whether the heat welding state is appropriate.

The detection device 10 includes a sensor 12, which includes an adapter 14 attached to the end of the opening 4a and a polarizing plate 16 provided at the tip of the adapter 14. As the sensor 12, for example, a general-purpose mark sensor can be used. Here, since the general-purpose mark sensor is for recognizing the color and for identifying the presence or absence of the color, it is necessary to perform alignment in order to observe the color of the heat-sealed portion 9. Therefore, a photo sensor 18 for synchronous output is provided, and the photo sensor 18 causes the eye mark 5
Is configured to detect. That is, regarding the positional relationship between the eye mark 5 and the opening 4 (4a), the general-purpose mark sensor 12 can observe the color of the heat seal portion 9 at the time when the synchronous output photosensor 18 detects the eye mark 5. It is configured to be in a state. In other words, when the synchronous output photosensor 18 detects the eye mark 5, the fact is input to the control unit (reference numeral 20 in FIG. 2) (indicated by arrow U). Then, the unit 20 stops the line to stop the progress of the paper material 1, and thereby causes the general-purpose mark sensor 12 to observe the color of the heat-sealed portion 9 to perform necessary measurement. The specific content of the measurement will be described later.

In place of the general-purpose mark sensor, a full-color mark sensor capable of measuring the reflectance of a predetermined area (for example, trade name "S" manufactured by Izumi Electric Co., Ltd.)
A1K ", etc.) can also be used.

Further, a so-called image processing system can be adopted instead of the above-mentioned sensor.

FIG. 2 is a block diagram for explaining the control mode of the detection apparatus 10. The output of the mark sensor 12 is from the line L1 and the photo sensor 18 for synchronous output.
Output of the control unit (CPU) 20 via line L2.
Has been entered in. As described above, when the synchronous output photosensor 18 detects the eye mark 5, the control unit 2
0 outputs a signal instructing to stop the progress of the paper material 1 via the line L3. In FIG. 2, reference numeral 22 is a power supply and reference numeral 24 is a noise filter.

FIGS. 3 to 5 show details of the adapter indicated by reference numeral 14 and the polarizing plate indicated by reference numeral 16 in FIG. In FIG. 3, an adapter indicated by reference numeral 14 is attached to the sensor tip portion 12e via a sensor attachment bracket 28. Here, in addition to the sensor mounting bracket 28, the adapter 14 includes the first and second polarizing plates 30, 3
2, a first polarizing plate mounting bracket 34, and a second polarizing plate mounting bracket 36 are included. The polarizing plate 16 is composed of first and second polarizing plates 30 and 32.

The first polarizing plate 30 can be adjusted by 90 degrees in the clockwise direction, as shown by the arrow CW in FIG. On the other hand, the second polarizing plate 32 can be adjusted 90 degrees counterclockwise as indicated by the arrow CCW in FIG.

Next, a specific example of the measurement of the present invention will be described mainly with reference to FIGS.

In FIG. 1, the paper material 1 advances in the direction of arrow M, and the polyethylene film 2 is unwound from the reel 6 in synchronization with this. The film 2 is heat-welded onto the paper material 1 by the heat seal portion 3. Then, color detection (combining polarizing plates for easy identification) is performed (step S1 in FIG. 6).

When the paper material 1 to which the polyethylene film 2 has been heat-welded moves and the eye mark 5 is detected by the synchronous output photosensor 18, a synchronous signal is output from the sensor (step S2).

This synchronization signal is transmitted to the control unit 20 (FIG. 2).
The movement of the paper material 1 is stopped by a signal from the unit, and the thermal welding state is observed by the detection device 10. As described above, when the thermal welding is performed well, when the opening (detection point) 4a is observed through the polarizing plate 16, the opening 4a is observed as the same color as the other portions. .. On the other hand, if the heat welding is not good, the opening 4
The color of e is observed differently than the other parts. This observation result is input to the control unit 20 (FIG. 2), and the area ratio between the discolored portion and the non-discolored portion in the heat-welded region of the opening 4e is obtained (step S3). And
When the ratio of the area of the discolored portion is smaller than the predetermined value, it is determined that the heat welding is properly performed (O in step S3).
K), the operation of the line is continued (step S4).

It is considered effective to set the empirical value to 5% as the predetermined value. However, this numerical value (predetermined value of 5%) may vary on a case-by-case basis depending on the type of product, the load applied in the shipping or distribution process, and other conditions.

On the other hand, when the area ratio of the discolored portion is larger than the predetermined value (NG in step S3), it is determined that the synthetic resin film is not properly heat-welded, and the machine automatically stops. (Step S5), the seal portion or the portion that becomes the container, which has been poorly heat-sealed, is removed (step S6), and the cause of the defect is sought and repaired (step S7).

In the embodiments of FIGS. 1 to 6, the polarizing plate 16 is attached to the sensor 12 when observing the discolored portion and the non-discolored portion in the detection portion through the polarizing plate, but other embodiments are also possible. It is possible. For example, as shown in FIG. 7, a plate 42 made of a polarizing plate may be arranged between the paper material 1 to which the polyethylene film 2 as the detection target is heat-welded and the color sensor 40 as the detection means. The other configurations of the embodiment of FIG. 7 are substantially the same as those of the embodiments of FIGS.

FIGS. 8 and 9 show the results of observation through a polarizing plate, and the two points shown in FIG. 8 are the ones where thermal welding was performed relatively well. On the other hand, the one particularly shown on the lower side of FIG. 9 has a poor thermal welding.

In the embodiment shown in FIGS. 8 and 9, C is provided through a polarizing plate.
A frame is provided at the mouth opening for observation with a CD camera, and the quality of heat welding is determined by counting how much (number of pixels) the image in the frame is discolored. In the case of FIG. 9, the reference value was set to 100 pixels, but there were 100 or more pixels that were discolored, so it was determined to be defective.

[0038]

The effects of the present invention are listed below.

(1) Whether or not the heat welding has been favorably performed is easily and accurately determined in real time.

(2) It is possible to determine whether or not the heat welding has been favorably performed without requiring a large-scale facility as in the past.

(3) Even in the case of discrimination, an extremely simple operation is sufficient, and a complicated process as in the past is not required.

(4) The labor required for determining the suitability of heat welding is significantly reduced.

(5) Especially, if the work is carried out manually by the worker, the labor of discrimination can be further reduced.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an embodiment of the present invention.

FIG. 2 is a block diagram of a control portion of the embodiment of FIG.

3 is a side view of a polarizing plate used in the embodiment of FIG.

4 is a sectional view taken along line IV-IV in FIG.

5 is a cross-sectional view taken along line VV of FIG.

FIG. 6 is a diagram showing an operation flowchart of the embodiment of FIG.

FIG. 7 is a side view showing another embodiment of the present invention.

FIG. 8 is a view showing a result of observing, through a polarizing plate, what has been relatively well heat-welded.

FIG. 9 is a view showing a result of observing, through a polarizing plate, one having poor heat welding.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Paper material 2 ... Polyethylene film 3 ... Heat seal part 4 ... Opening part 4a ... Opening part (detection location) 5 ... Eye mark 6 ... Reel 7, 8 ... ..Roller 10 ... Detecting device 12 ... Sensor 14 ... Adapter 16 ... Polarizing plate 18 ... Synchronous output photosensor 20 ... Control unit

Claims (2)

[Claims] 1. A method for detecting a heat-welded state of a film for determining whether or not a synthetic resin film is properly heat-welded, wherein a polarizing plate is positioned in the vicinity of a detection position where the heat-welded state is to be detected. Step, observing the discolored spot and the non-discolored spot in the detection spot through the polarizing plate, and determine whether the ratio of the area of the discolored spot to the area of the non-discolored spot is larger or smaller than a predetermined value. , If the area ratio of the discolored portion is larger than a predetermined value, it is determined that the synthetic resin film is not properly heat-welded, while if the area ratio is smaller than the predetermined value, heat is appropriately applied. And a step of determining that the film has been welded, and a method for detecting a heat-welded state of a film. 2. A polarizing plate positioned in the vicinity of a detection location for detecting the heat-welded state in a film heat-welded state detecting device for determining whether or not the synthetic resin film is properly heat-welded. And a measuring means for observing the discolored part and the non-discolored part in the detection part through the polarizing plate and measuring the area of the non-discolored part and the area of the discolored part, and the ratio of the area of the discolored part from a predetermined value. If it is also large, it is determined that the synthetic resin film is not properly heat-welded, and on the other hand, if the ratio of the area is less than a predetermined value, it is determined that it is properly heat-welded, An apparatus for detecting a heat-welded state of a film, comprising: