JPH10203512A - Method and apparatus for inspecting sealed state of container mouth, sealing structure of container mouth, synthetic resin container, screw cap and preform of the synthetic resin container suitable for the inspecting method and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a container to be evaluated in its sealability without unplugging the container by placing markers having a certain positional relation with a screw end of each threaded part of the container and a screw cap and determining whether or more screwing is appropriate from the positional relation of a pair of markers after the screw cap is mounted. SOLUTION: A container is equipped with a male screw 11 to be screwed with a screw cap 20 on an outer periphery of a mouth 10, and a cap locking ring 12 and a support ring 13 are formed below it. In this case, markers M1, M2 provided along an outer periphery of the support ring 13 and an outer periphery of the screw cap 20 are provided to be in a line at a predetermined distance in an axial X-direction of the mouth 10 when the screw cap 20 is screwed into the male screw 11 by a predetermined amount to have the mouth 10 sealed. When a screwed amount of the screw cap 20 is inappropriate, since the marker M2 is shifted in a peripheral direction with respect to the marker M1, it is determined that the screw cap has been appropriately mounted by a size of this shift.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in inspection of a sealed state between a screw cap and a synthetic resin container such as a beverage bottle.

[0002]

2. Description of the Related Art As a synthetic resin container for beverages and the like, a container in which a container mouth is sealed with a screw cap is well known.
In this type of container sealing process, several containers are extracted as samples after screw caps are attached, and the opening torque of the screw caps for these containers is measured to check whether the mouth is properly sealed. I was

[0003]

In the conventional inspection method,
The sample opened after filling the contents loses commercial value. Therefore, the loss increases as the number of inspections increases, and the production cost is reduced.

The present invention relates to an inspection method and an inspection apparatus capable of evaluating the sealing performance of a container without opening the container, a sealing structure of a container opening suitable for carrying out the inspection method and the inspection apparatus, and a synthetic resin container. , A screw cap and a preform of a synthetic resin container.

[0005]

Hereinafter, the present invention will be described with reference to the drawings showing embodiments of the present invention. However, the present invention is not limited to the illustrated embodiment.

According to the first aspect of the present invention, a screw cap 2 screwed into an outer periphery of a container 2 and an opening 10 of the container 2 is provided.
0 and the screw ends 1 of the respective screw portions 11 and 22
Marker M having a fixed positional relationship with respect to 1a and 22a
1, M2 is provided, and after the screw cap 20 is mounted, the above-described method is used to determine whether or not the screw state of the screw cap 20 is appropriate based on the positional relationship between the pair of marks M1 and M2. Achieve the goal. According to the second aspect of the present invention, in the inspection method of the first aspect, the pair of markers M in the circumferential direction of the container mouth portion 10 are provided.
1. The suitability of the screwed state of the screw cap 20 is determined based on the deviation amount θ (or Y) of M2. further,
According to the third aspect of the present invention, in the inspection method of the first aspect, the screw cap 20 is set based on the shift amount θ (or Y) and Lx of the pair of markers M1 and M2 in the circumferential direction and the axial direction of the container opening 10 respectively. It is determined whether the screwed state is appropriate.

According to a fourth aspect of the present invention, a screw cap 2 is provided.
A pair of markers M1 provided on an outer periphery of the container 2 and an outer surface of a screw cap 20 screwed into the opening 10 of the container 2; A relative position detecting means 33 for detecting a mutual positional relationship of M2 based on image information acquired by the photographing means 31 and a relative position of a pair of markers M1 and M2 detected by the relative position detecting means 33. The above-described object is achieved by a device for inspecting the sealed state of a container mouth provided with a judging means 33 for judging whether the screwed state of the screw cap 20 is proper or not.

According to a fifth aspect of the present invention, there is provided a structure in which a screw cap 20 is screwed into a container mouth portion 10 to seal the mouth portion 10, and a pair of screws having a fixed positional relationship when the screw cap 20 is screwed in a predetermined amount. The above-mentioned object is achieved by the sealing structure of the container mouth portion provided with the marks M1 and M2 on the outer surfaces of the container 10 and the screw cap 20, respectively. According to the invention of claim 6, in the sealed structure of claim 5, when the screw cap 20 is screwed into the mouth 10 by a predetermined amount, the pair of markers M1, M2
Are aligned in the axis X direction of the container opening 10.

The invention according to claim 7 is a screw cap 2
A male screw part 11 for screwing with the female screw part 22 and a screw end 11a of the screw part 11 are provided outside the area covered by the screw cap 20 on the outer surface of the container so as to maintain a fixed positional relationship. Resin container 2 provided with marked M1
Thereby, the above-described object is achieved. According to the invention of claim 8, in the synthetic resin container 2 of claim 7, a ring portion 13 is provided below the male screw portion 11, and a mark M1 is provided on an outer periphery of the ring portion 13.

According to the ninth aspect of the present invention, the external thread portion 1 of the container 2 is provided.
The screw cap 20 has a female screw portion 22 for screwing with the screw member 1 and is provided with a sign M2 on its outer surface so as to maintain a fixed positional relationship with the screw end 22a of the female screw portion 22 to achieve the above-mentioned purpose. To achieve.

According to the tenth aspect of the present invention, a preform of a synthetic resin container having a mouth portion 10 provided with an external thread portion 11 for screwing with a screw cap 20 and a body portion 4 expanded by blow molding. In the body 1, outside the area covered by the screw cap 20 on the outer periphery of the mouth,
The above-described object is achieved by providing the mark M1 so as to maintain a fixed positional relationship with the first screw end 11a.

[0012]

FIG. 4 shows a synthetic resin container 2 for beverages to which the present invention is applied, and FIG. 5 shows a preform (also called a parison) 1 of the container 2.
The preform 1 is manufactured by injection molding using a synthetic resin as a raw material, and the container 2 is manufactured by blow molding the preform 1. The preform 1 has a mouth portion 10 and a hollow cylindrical body portion 4 following the mouth portion 10.
Expands to form the body 5 of the container 2. Preform 1
The mouth 10 is restrained in the mold during blow molding and does not expand. Therefore, the mouth of the container 2 is the mouth 1 of the preform 1.
Equal to zero shape. Therefore, hereinafter, the same reference numerals are used for the mouths of the preform 1 and the container 2.

A screw cap 2 is provided on the outer periphery of the mouth 10.
0 (see FIG. 1) is provided with a male screw portion 11, and a cap locking ring 12 and a support ring 13 are formed below the male screw portion 11. The cap locking ring 12 engages with a separable proof ring 21 (see FIG. 1) provided at the lower end of the screw cap 20 when the screw cap 20 is loosened with respect to the screw portion 11. Between the locking ring 12 and the support ring 13.

As shown in detail in FIG. 1A, a pair of markers M1 and M2 are provided on the outer periphery of the support ring 13 and the outer periphery of the screw cap 20, respectively.
These marks M1 and M2 indicate that when the screw cap 20 is screwed into the male screw portion 11 (for example, equivalent to 1.5 rotations of the screw cap 20) and the mouth portion 10 is sealed with a specified torque, It is provided so as to be aligned at a predetermined distance Lr in the X axis direction of ten.

If the screwing amount of the screw cap 20 is inappropriate, as shown in FIGS. 1B and 1C,
The marker M2 is shifted in the circumferential direction with respect to the marker M1. It is possible to determine whether or not the screw cap 20 is correctly mounted based on the magnitude of the deviation amount. Note that the amount of deviation in the circumferential direction may be represented by either the deviation angle θ with respect to the axis of the mouth 10 or the distance Y of the mouth 10 in the radial direction. Also, due to the displacement of the screw cap 20, the distance Lx in the axial direction of the marks M1 and M2 becomes the reference distance Lr.
Changes from. When it is determined whether or not the screwing amount of the screw cap 20 (the sealing property of the mouth portion 10) is appropriate based on only the circumferential deviation amount θ or Y, the state in which the screw cap 20 is loosened by a predetermined number of 360 ° from the position where the screw cap 20 is screwed in is determined. Although indistinguishable, such inconvenience can be eliminated by comparing the magnitudes of the distances Lx and Lr.

In order to enable the above-described discrimination, the markers M1 and M2 are provided on the container 2 and the screw cap 20 as follows.

First, as shown in FIG. 2, the mark M1 is provided with a screw end 11a of the male thread 11 in the direction of the axis X of the mouth 10.
And the axial distance A between them is kept constant with respect to the large number of preforms 1 and the containers 2. Then, the position of the marker M2 is determined so as to align with the marker M1 in the axis X direction when the screw cap 20 is screwed into the mouth portion 10 by a predetermined amount. Screw end 22a of female screw portion 22 of screw cap 20 (see FIG. 3A)
The distances B and C in the circumferential direction and the axial direction between the screw cap 20 and the marker M2 are always kept constant for a large number of screw caps 20. The screw ends 11a and 22a here are ends on the screwing start side of the screw portions 11 and 22 with respect to the mating side. That is, the screw end 11a of the male screw portion 11 is
The screw end 22 a of the female screw portion 22 is on the opening side of the screw cap 20.

The mouth portion 10 is formed by injection molding using resin as a material, and the screw cap 20 is formed by compression molding, injection molding or the like using resin as a material. If the marks M1 and M2 are formed at the time of molding, the respective screw ends 11
a and 22a and the markers M1 and M2 can be maintained in a fixed positional relationship. In this case, the marks M1 and M2 can be formed as concave portions or convex portions.

The method of manufacturing the preform 1 into the synthetic resin container 2 includes a cold parison method in which the preform 1 is removed from the mold and blow-molded into the synthetic resin container 2 in a separate step. There are two types, a hot parison method, in which the molded article 1 is molded and then blow-molded in a heated state. In the former method, the preform 1
Even if the mark M1 is provided on the body 4 at the molding stage of
The relationship between 1 and the screw end 11a cannot be kept constant by blow molding. Therefore, it is necessary to provide the mark M1 in an area where the mark M1 does not deform during blow molding, that is, on or above the support ring 13 and not covered with the screw cap 20. On the other hand, in the latter hot parison method, the sign M1 can be provided on the body 5. Marks M1 and M2 may be printed after molding of container 2 and screw cap 20, respectively.

In the illustrated example, the markers M1 and M2 are both formed in a rectangular shape. However, the markers M1 and M2 may be formed in various shapes such as a star-shaped marker M2 as shown in FIG. However, a shape that can be distinguished at a glance is desirable. As for the sign M2, as shown in FIG. 3C, the sign M2 may be configured by omitting a part of the multiple ridges 23 formed on the outer periphery of the screw cap 20. Markers M1, M2
Is desirably about 0.3 mm to 1.0 mm. When the marks M1 and M2 are formed by printing, they may be colored in a conspicuous color.

FIG. 6 shows an outline of an apparatus for inspecting the sealed state of the container mouth using the above-mentioned markers M1 and M2. The inspection device 30 takes an image of the vicinity of the mouth of the container 2 sealed with the screw cap 20 with an imaging unit 31 such as a CCD camera, and converts an image signal output from the imaging unit 31 into an A / D converter 32. The digital signal is converted into a digital signal and taken into a central processing controller (hereinafter referred to as a CPU) 33.
The signal is subjected to necessary processing and stored in the memory 34.
The CPU 33 has an input device (for example, a keyboard) 36 and a monitor 37 via an input / output interface 35.
Is connected. The CPU 33 is configured by combining, for example, a microprocessor, various peripheral circuits necessary for the operation thereof, a temporary storage element, and the like, and performs various calculations and processes required for inspection of a sealing state in accordance with an instruction from the input device 36.

FIG. 7 is a flow chart showing the procedure of the inspection process of the sealed state of the container mouth portion executed by the CPU 33. When an inspection start is instructed from the input device 36, C
The PU 33 reads the image signal from the photographing unit 31 and stores the image signal in the memory 34 as needed (Step S1). In the next step S2, a process of detecting an image corresponding to the markers M1 and M2 from the read image is performed.
For this processing, various known image processing methods such as binarization, edge extraction, and pattern matching may be used. When the detection is completed, it is determined in a step S3 whether or not the markers M1 and M2 have been detected, and if not detected, the process proceeds to a step S10 to display on the monitor 37 that the determination is impossible and the process is terminated. In this case, for example, the container 2 does not exist,
There are various factors such as signs M1 and M2 not being predetermined.

If the markers M1 and M2 have been detected, the process proceeds to step S4, where the distances L related to the markers M1 and M2 are determined.
x and Y (see FIG. 1) are calculated. In a succeeding step S5, it is determined whether or not the calculated distances Lx, Y are within an allowable range. If it is within the allowable range, the fact that the sealing state is good is displayed on the monitor 37 in step S7. If it is outside the allowable range, the fact that the sealing state is bad is displayed on the monitor 37 in step S8, and the process is terminated. Various countermeasures such as sounding an alarm when a defect is detected, stopping the filling line of the container 2, and removing the container 2 determined to be defective from the line may be added.

When there is no possibility that the screwed amount of the screw cap 20 deviates from the specified amount by 360 ° or more, only the distance Lx may be determined in the above processing. When the screwed amount of the screw cap 20 reaches a predetermined amount, the markers M1 and M2 do not have to be aligned in the axial direction of the mouth portion 10, and even if the markers M1 and M2 are shifted by a certain angle in the circumferential direction as a reference. Good.

[0025]

EXAMPLE In the above embodiment, 13 containers 2 having an external diameter of the external thread 11 set to 28 mm and corresponding screw caps 20 were prepared, and the signs M1, M
2, angle L, distance Lx, Y, and screw cap 20
Table 1 shows the results of measurement of the relationship between the torque required for opening and the sealing property of the mouth portion 10.

[0026]

[Table 1] From this result, a clear correlation was recognized between the angle θ, the distance Lx, Y, the opening torque, and the sealing performance, and the sealing performance was ensured for all the containers 2 without opening the screw cap 20 according to the present invention. It was proved that it can be evaluated.

[0027]

As described above, according to the inspection method of claims 1 to 3, the mouth portion is sealed by the screw cap according to the relative positions of the pair of markers provided on both the container and the screw cap. Since the state can be evaluated, it is not necessary to extract a part of the containers after filling the contents and measure the opening torque as in the related art. Therefore, the sealing property can be inspected nondestructively for all the containers, and the reliability of the product can be remarkably increased while the inspection cost is kept low. In particular, according to the second aspect of the present invention, it is possible to accurately determine whether the screwed state is good or bad by using the amount of displacement of the pair of signs in the circumferential direction. By doing so, the quality of the screwed state can be more accurately determined.

According to the inspection device of the fourth aspect, the relative position of the pair of markers can be detected from the image information acquired by the photographing means to determine whether the screw cap is screwed properly. The method can be easily implemented. For example, by installing the inspection device of the present invention in the container filling line, it is possible to non-destructively inspect the sealing properties of all containers, while increasing the reliability of the production process while suppressing an increase in inspection costs, and If any abnormality occurs in the cap mounting process, it is possible to quickly cope with the abnormality.

According to the sealing structure of the fifth and sixth aspects, it is possible to easily determine whether the screwed state of the screw cap is appropriate or not by the pair of markers provided on the container and the screw cap. Therefore, by using the sealing structure of the present invention, it is possible to increase the reliability while suppressing an increase in the cost required for the sealing test. In particular, according to the sealing structure of the sixth aspect, the appropriateness of the screwed state can be immediately determined based on how much the pair of markers deviates from the aligned state, and the labor required for the inspection can be greatly reduced.

According to the synthetic resin containers of claims 7 and 8, and the screw cap of claim 9, the inspection method and the sealing structure of the present invention can be easily implemented by combining the respective labels. In particular, according to the synthetic resin container of the eighth aspect, a marker can be provided at a position suitable for the so-called cold parison method in which the molding of the preformed body and the blow molding to the container are performed in separate steps.

According to the tenth aspect of the present invention, since the marker can be formed at the stage of forming the screw portion, the positional relationship between the screw end of the screw portion and the marker can be reliably maintained constant. Therefore, the synthetic resin container according to claims 7 and 8 can be easily manufactured.

[Brief description of the drawings]

FIG. 1 is a view showing a sealed state of a container mouth portion according to an embodiment of the present invention, wherein (a) shows a sealed state as prescribed;
(B) shows a state where the screwing amount of the screw cap is shifted, and (c) shows a state as seen from above (b).

FIG. 2 is an enlarged view showing a part II in FIG. 4;

FIG. 3 is an enlarged view showing a screw cap according to one embodiment of the present invention.

FIG. 4 is a view showing the appearance of a synthetic resin container according to one embodiment of the present invention.

FIG. 5 is a view showing a preform for manufacturing the synthetic resin container of FIG. 4;

FIG. 6 is a block diagram of an inspection device according to an embodiment of the present invention.

FIG. 7 is a flowchart showing an inspection procedure executed by the apparatus shown in FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Preformed body 2 Synthetic resin container 4,5 Body 10 Mouth part 11 Male thread part 11a Screw end of male thread part 13 Support ring 20 Screw cap 22 Female thread part 22a Female thread part screw end 30 Inspection device 31 Imaging part 33 CPU M1, M2 sign

Claims (10)

[Claims] 1. A sign having a fixed positional relationship with a screw end of each screw portion is provided on an outer periphery of a container and an outer surface of a screw cap screwed into a mouth portion of the container. Determining whether the screw cap is properly screwed or not based on the positional relationship between the pair of markers after mounting the seal. 2. The screw cap according to claim 1, wherein the screw cap is properly screwed in on the basis of a displacement of the pair of markers in a circumferential direction of the container opening.
Inspection method of the sealing state of the container mouth part described in the above. 3. The container according to claim 1, wherein whether the screwed state of the screw cap is screwed or not is determined based on a shift amount of the pair of markers in each of a circumferential direction and an axial direction of the container opening. Inspection method for sealing of the mouth. 4. A photographing means for photographing a mouth portion of a container into which a screw cap is screwed, a pair of markers provided on an outer periphery of the container and an outer surface of a screw cap screwed into the mouth portion of the container. A relative position detecting unit that detects a mutual positional relationship based on image information obtained by the photographing unit; and the screw cap based on a relative position of the pair of markers detected by the relative position detecting unit. Determining means for determining whether the screwed state of the container is proper or not. 5. A structure in which a screw cap is screwed into a container mouth to seal the mouth, wherein a pair of markers having a fixed positional relationship when the screw cap is screwed in a predetermined amount include the container and the mark. A container mouth sealing structure, which is provided on an outer surface of a screw cap. 6. The container according to claim 5, wherein when the screw cap is screwed into the mouth by the predetermined amount, the pair of markers are aligned in an axial direction of the mouth of the container. Mouth sealing structure. 7. A male screw part for screwing with a female screw part of a screw cap, and a fixed positional relationship with a screw end of the male screw part outside an area covered by the screw cap on an outer surface of the container. A synthetic resin container comprising: 8. The synthetic resin container according to claim 7, wherein a ring portion is provided below the male screw portion, and the mark is provided on an outer periphery of the ring portion. 9. A container having a female screw portion for screwing with a male screw portion of a container, and a mark provided on an outer surface thereof so as to maintain a fixed positional relationship with a screw end of the female screw portion. A screw cap characterized by the following. 10. A preform of a synthetic resin container having a mouth portion provided with a male screw portion for screwing with a screw cap and a body portion expanded by blow molding, wherein: A preform of a synthetic resin container, characterized in that a mark is provided outside a region covered by a screw cap so as to maintain a fixed positional relationship with a screw end of the male screw portion.