JP2004117103A - Label tear inspection device of vessel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect accurately label tear independently of a design even in the case where a label mounted on the vessel surface is transparent. <P>SOLUTION: This device is equipped with an illumination device 4 for irradiating the label 3 mounted on the vessel surface with light, and an imaging device 5 for imaging reflected light from the label 3 surface illuminated by the illumination device 4. A tear part 33 is detected by the difference of reflection characteristics between a normal part 32 and the tear part 33 of the label 3. The illumination device 4 has a constitution for irradiating the label 3 obliquely with diffused light, and the imaging device 5 has a constitution for imaging regularly reflected light from the label surface. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an apparatus for inspecting the breakage of a label attached to a transparent container such as a PET container.
[0002]
[Prior art]
In a conventional container breakage inspection device, light is emitted from the rear side of a transparent container, and an image of a label silhouette is captured by an imaging device and converted into an electric signal. The image pickup apparatus uses an image pickup device such as a CCD, for example, and divides an inspection area on a label surface into a predetermined number of pixels, and recognizes light and dark in each pixel area with a predetermined number of gradations. I have.
In the photographed label image, the normal part is dark because the light is blocked, and the torn part is lightened by transmitting the light. By performing the binarization process, the broken portion is determined by setting only the broken portion as a white image and the normal portion as a black image.
[0003]
However, this type of lighting from behind is effective for opaque labels, but for transparent or translucent labels, the light from behind passes through the label, and the part other than the torn part The normal part is also brightened similarly to the part to which light is transmitted and broken, so that it is difficult to determine whether the part is broken or a normal part.
Therefore, for example, as described in Patent Literature 1 and Patent Literature 2, it is conceivable to image reflected light from a label.
[Patent Document 1] JP-A-4-138306 [Patent Document 2] JP-A-2001-174236
[Problems to be solved by the invention]
However, since transparent and printed opaque parts are mixed on the label surface, there are torn spots and confusing gradation steps in the normal part of the imaged label. Cannot distinguish between a broken part and a normal part by the binarization processing. If the design is constant, it is conceivable to ignore the design part at the gradation level that is confusing as a broken part, but it is impossible to determine if the design changes.
[0005]
The present invention has been made to solve the above-mentioned conventional problems, and even if the transparency of the label attached to the surface of the container is high, the label of the container can be detected with high accuracy regardless of the design regardless of the design. An object of the present invention is to provide a tear inspection device.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention, an illuminating unit that irradiates light to a label attached to the surface of a container, and an imaging unit that captures reflected light from the label surface illuminated by the illuminating unit In a label breakage inspection device for a container that detects a broken portion by a difference in reflection characteristics between a normal portion and a broken portion of the label,
The illumination unit is configured to irradiate the diffused light to the label surface obliquely, and the imaging unit is configured to image the regular reflection light from the label surface.
[0007]
Further, two sets of inspection units are provided as one set of the illuminating means and the imaging means, and the two sets of inspection units are arranged on opposite sides of the transport path of the container to detect label breakage on both front and back surfaces of the container. It is characterized in that the configuration is such that:
[0008]
It is preferable that the two inspection units are arranged so that the positional relationship between the illumination unit and the imaging unit is opposite to each other.
It is effective that the inspection area of the label is in the vicinity of the fold that has been attached to the label before being attached to the container.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described based on the illustrated embodiments.
FIG. 1 shows a label break inspection apparatus for a container according to an embodiment of the present invention.
The label breakage inspection apparatus 1 for a container is installed on a conveyor 11 at a palletizer entrance (not shown) and includes two inspection units 10 and 10 for inspecting both front and rear surfaces of a label 3 attached to a container 2. ing.
[0010]
The container 2 is a transparent container such as a PET bottle as shown in FIG. 2. In this embodiment, the container 2 has a cylindrical body 21 extending in a tubular shape and a bottom 22 closing a lower end of the body 21. And a shoulder 23 extending obliquely from the upper end of the body 21 upward so as to gradually decrease in diameter, and a mouth and neck 24 projecting upward from the shoulder 23. At this stage, the cap is not attached with an empty container. The cross-sectional shape of the body 21 is such that four rectangular corners are cut in a straight line, and the whole is an octagon.
[0011]
The label 3 is made of a shrink film on which various information such as a product name is printed, and is adhered to the surface of the body 21 by heat shrinkage of the film. The upper end of the label 3 extends to the shoulder 23. The label 3 is provided with a fold 31 before being attached to the container. Since the fold 31 is most often torn, the inspection area 12 by the inspection unit 10 is limited to the vicinity of the fold 31. . In the present embodiment, the folds 31, 31 are located near the center of the front surface and the rear surface of the container 2.
The label 3 is formed from a long film 100 formed in a cylindrical shape, and is wound in a roll shape in a state of being folded flat, and as shown in FIGS. 3 (A) and 3 (B). Are fed out along the feeding guides 101, 101, cut at predetermined lengths, spread out as shown in FIG. 3C, and mounted on the container 2 by a mounting machine (not shown). At the time of the above-mentioned feeding, the left and right folds 31, 31 of the label may be rubbed by the feeding guide 100 or the like, resulting in small scratches. When the label 3 is subjected to thermal shrinkage after mounting on the container, the damage spreads as if melted by heat and breaks.
[0012]
The container 2 is transported by the transport conveyor 11 so that the front and rear surfaces thereof are parallel to the transport direction. The two sets of inspection units 10 and 10 are opposed to each other across the transport conveyor 11 which is the transport path of the container 2. Is located on the side.
[0013]
Each inspection unit 10 serves as an illuminating device 4 for illuminating the label 3 attached to the surface of the container 2 with light, and an imaging device for imaging reflected light from the surface of the label 3 illuminated by the illuminating device 4. And an imaging device 5. Each imaging device 5 is connected to a computer (not shown), the image is binarized by the computer, and the broken portion 33 is determined based on the difference in the reflection characteristics between the normal portion 32 and the broken portion 33 of the label 3. .
[0014]
The illuminating device 4 and the imaging device 5 are spaced apart from each other by a predetermined distance in the direction in which the container is transported. Is configured to capture the specularly reflected light from the camera.
That is, as shown in FIG. 1C, the light is specularly reflected at a reflection angle θ equal to the incident angle θ of the incident light from the illumination device 4 with respect to a normal Y passing through the center of the inspection area 12 of the label 3. The imaging device 5 is arranged on the optical axis of the regular reflection light. Since the light from the illuminating device 4 has weak directivity and is emitted in a diffused manner, the directions of the illuminating device 4 and the imaging device 5 may be slightly shifted.
[0015]
The inspection units 10 and 10 are arranged at predetermined intervals in the transport direction, and the positional relationship between the illumination device 4 and the imaging device 5 of each inspection unit 10 and 10 is opposite to each other. The light from the lighting device 4 of the unit 10 is not affected by the inspection by the other inspection unit 10. That is, the image pickup device 5 of the other inspection unit 10 is arranged so as not to be located on an extension of the light emitted from the illumination device 4 of the one inspection unit 10, and the light that has passed through the container 2 and leaked behind is the other. The inspection unit 10 is designed so as not to enter the imaging device 5 of the inspection unit 10, and both sides of the container 2 can be inspected.
[0016]
The illumination device 4 can use various light sources such as a fluorescent lamp, an LED, and a halogen lamp, and diffuses light from the light source by a diffusion plate or the like. The shape of the light source may be a point light source, a linear light source, or a light source arranged in a ring shape.
The imaging device 5 uses, for example, a CCD imaging device or the like, and divides the inspection area on the label surface into a predetermined number of pixels, and recognizes light and dark in a predetermined number of gradations for each pixel area.
[0017]
In the container label breakage inspection apparatus of the present embodiment, when the container 2 flowing on the conveyor 1 reaches the inspection position, the inspection units 10 and 10 inspect the presence or absence of a broken portion. That is, the label 3 of the container 2 is illuminated by the illumination device 4 of each inspection unit 10, and is imaged by the imaging device 5. The captured image is sent to a computer (not shown), and the computer performs a binarization process on the inspection region 12 of the captured image based on a predetermined threshold. Since there is no regular reflection of light, the torn portion 33 can be extracted as a black image.
[0018]
In an actual test, it was possible to detect a hole with a diameter of 3 mm or more in a label of a 2-liter PET container with the width of 70 mm × 30 mm at the center of the label as the inspection area 12. Although the entire label is not inspected, the breakage of the label is 80% or more in the vicinity of the fold, and the effect is great.
When the torn portion 33 is extracted, the container 3 is automatically rejected as a label defect, and the occurrence time is displayed, the number of inspections, the number of defect inspections, and the like are counted and managed.
[0019]
【The invention's effect】
As described above, according to the first aspect of the present invention, the illuminating unit irradiates the diffused light obliquely to the label surface, and the imaging unit captures the specularly reflected light from the label surface. Therefore, the light incident on the image pickup means is reflected light depending on the gloss of the label surface, so that an image with almost uniform brightness can be obtained regardless of the label design. Further, the broken portion becomes reflected light from the surface of the container having a different reflection characteristic from the label surface, and the broken portion can be accurately determined.
Further, since the light is diffuse light, the brightness of the specularly reflected light incident on the imaging means does not change even if the direction of the container slightly varies.
[0020]
According to the second aspect of the present invention, the two inspection units are arranged on opposite sides of the transport path of the container to detect tearing of the labels on both the front and back sides of the container. Can be detected.
According to the third aspect of the present invention, the two inspection units are arranged so that the positional relationship between the illumination unit and the imaging unit is opposite to each other, so that the illumination light from the illumination unit of one inspection unit is used for the other inspection unit. Not affected by inspection by the inspection unit.
According to the fourth aspect of the present invention, since the inspection range is set near the fold attached to the label before the container is attached to the container, it is possible to inspect the tear most efficiently.
[Brief description of the drawings]
FIG. 1A is a schematic configuration diagram showing a container label breakage inspection device according to an embodiment of the present invention, FIG. 1B is a schematic diagram of an inspection region, and FIG. FIG. 4 is a diagram illustrating an arrangement relationship between the image forming apparatus and the imaging apparatus.
FIG. 2 is a front view showing an example of a container inspected by the apparatus of FIG.
3A and 3B are explanatory views of a label mounting procedure. FIG. 3A is a plan view of a feed guide portion, FIG. 3B is a sectional view taken along line BB of FIG. 3A, and FIG. (C) is a diagram showing the relationship between the fold and the container when the label is attached.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Inspection apparatus 2 Container 21 Body part, 22 Bottom part, 23 Shoulder part, 24 Neck and neck part 3 Label, 31 Fold, 32 Normal part 33 Breakage part 4 Lighting device 5 Imaging device 10 Inspection unit 11 Conveyor 100 Film 101 Feed guide

Claims (4)

Illuminating means for irradiating a label mounted on the surface of the container with light, and imaging means for imaging reflected light from the label surface illuminated by the illuminating means, and a reflection characteristic of a normal part and a broken part of the label In a container label breakage inspection device that detects a broken part due to the difference in
The label breaking inspection apparatus for a container, wherein the illuminating means is configured to irradiate diffuse light to the label surface obliquely, and the imaging means is configured to capture specularly reflected light from the label surface. A configuration in which two sets of inspection units are provided as one set of the illuminating unit and the imaging unit, and the two sets of inspection units are arranged on opposite sides of the transport path of the container to detect tearing of labels on both front and back surfaces of the container. The container label tearing inspection device according to claim 1, wherein: 3. The container label breakage inspection device according to claim 2, wherein the two sets of inspection units are arranged such that the positional relationship between the illumination unit and the imaging unit is opposite to each other. 4. The container label breakage inspection apparatus according to any one of claims 1 to 3, wherein the label inspection region is near a fold that has been applied to the label before the label is attached to the container.

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