JP4508838B2 - Container mouth inspection device - Google Patents

Description

  The present invention relates to an inspection device for inspecting a defect (a scratch or a foreign object) in a mouth portion of a container.

A transmitted light method is known as a method for inspecting the mouth of containers such as PET bottles and preforms. The transmitted light method is a method in which light is emitted from the lighting device to the mouth, and the transmitted light transmitted through the mouth is received and inspected by an imaging device provided on the side opposite to the lighting device. As one form of the transmitted light system, a method is also known in which a convex bush is inserted into the mouth and the convex bush is lit to inspect (see, for example, Patent Document 1).
JP 2001-289790 A

  Since the mouth is provided with uneven parts such as threads, in the inspection using the transmitted light method, the shadow of the back side uneven part is reflected in the captured image on the inspection target side (front side) of the mouth, and the inspection accuracy is improved. Adverse effects. Further, since the captured image is distorted due to the shadow of the uneven portion present in the inspection target region or the difference in the thickness of the container due to the uneven portion, this also adversely affects the inspection accuracy. In the inspection method of Patent Document 1, since it is necessary to insert a convex bush into the mouth portion of each container, the inspection efficiency may be deteriorated.

  Therefore, the present invention suppresses the influence of the shape feature of the mouth such as the mouth of the container or the uneven portion behind it and the difference in thickness on the inspection accuracy, and inspects the mouth of the container with high accuracy and high efficiency. An object of the present invention is to provide an inspection device that can be used. In the present invention, the term “container” is a concept including not only a finished product container placed in the distribution process but also an intermediate product such as a preform as long as the mouth is formed.

The mouth inspection device (4) of the present invention is arranged along at least a part of the mouth (5) of the container (2) and emits illumination light (14) including a wavelength for exciting the mouth. An illumination device (6) for irradiating a part, an imaging means (10) for receiving excitation light (16) generated at the mouth part and acquiring an image of the mouth part formed by the excitation light; and the excitation part Filter means (9) for eliminating the influence of at least a part of wavelength band components other than the wavelength of light on the image, and the imaging means is arranged with the photographing direction opposite to the mouth. An optical system for guiding excitation light from the mouth to the imaging unit is disposed between the imaging unit and the illumination device, thereby solving the above-described problem.

According to the mouth inspection apparatus of the present invention, excitation light is generated at the mouth by irradiation of illumination light, and the excitation light is received by the imaging means, and an image of the mouth is taken. Unless there is a defect such as a scratch or a foreign object on the surface of the mouth or in the vicinity thereof, excitation light can be generated almost uniformly on the surface of the container, and the excitation light has a shadow like reflected light with respect to illumination light. Hard to make. On the other hand, if there is a defect on or near the surface of the container, the excited state changes, and the effect appears clearly in the image formed by the excitation light. In addition, since the frequencies of the illumination light causing excitation and the excitation light are different, the influence of at least a part of the wavelength region component of the illumination light on the image can be eliminated by using the difference in frequency. . By such an action, the mouth image based on the excitation light is suppressed while suppressing the shadow created by the uneven portion on the surface of the container, the difference in thickness of the uneven portion of the mouth portion, or the influence of the uneven portion behind the region to be inspected. The container can be inspected with high accuracy. Further, since it is not necessary to insert an inspection jig such as a bush into the mouth portion and hide the back of the mouth portion, the inspection efficiency can be increased. In addition, since the image pickup means is directed in the opposite direction with respect to the illumination device, there is no possibility that the illumination light from the illumination device is directly incident on the image pickup means, and the mouth inspection based on the excitation light can be performed more easily. Become.

  In one aspect of the present invention, the filter means may include an optical filter (9) that transmits the excitation light and absorbs at least a part of a wavelength band component other than the wavelength of the excitation light. According to such an aspect, the image of the mouth based on the excitation light is reliably acquired by the imaging unit while removing at least a part of the wavelength region components other than the wavelength of the excitation light before the light enters the imaging unit. can do. However, the filter unit in the present invention is not limited to an optical filter, and may be a filter unit that electrically removes at least a part of a wavelength region component other than the wavelength of excitation light from an image signal output from an imaging unit, for example. Good.

  1 aspect of this invention WHEREIN: The back surface reflecting plate (7) which reflects the said illumination light toward the said mouth part is provided in the back side of this mouth part with respect to the test | inspection area | region of the said mouth part by the said imaging means, The filter means eliminates the influence of wavelength region components other than the wavelength of the excitation light on the image within a range in which a part of the transmitted light reflected by the back reflector and transmitted through the mouth is reflected in the image. May be. According to this aspect, the illumination light reflected on the back reflector is guided from the back of the inspection target region to the mouth and transmitted through the mouth, and the transmitted light is also captured by the imaging unit. Imaging means for detecting the influence of defects existing in the mouth and on the inner peripheral surface on the transmitted light while reliably grasping the surface state of the inspection target area of the mouth using excitation light generated at or near the surface Can be reflected in the image acquired. Thereby, the inspection accuracy of defects other than the surface can be improved, and the reliability of the inspection can be further increased.

  In one aspect of the present invention, the distance between the mouth and the back reflector may be adjustable. According to this aspect, the influence of the transmitted light on the image acquired by the imaging unit can be changed by adjusting the distance between the back reflector and the mouth.

  In addition, in the above description, in order to make an understanding of this invention easy, the reference sign of the accompanying drawing was attached in parenthesis, but this invention is not limited to the form of illustration by it.

  As described above, according to the mouth inspection apparatus of the present invention, an image of the mouth is generated on or near the surface while suppressing the influence of the shape feature such as the uneven portion of the mouth on the inspection accuracy. It can be clearly obtained based on the excitation light. Further, it is not necessary to insert an inspection jig such as a bush into the mouth portion and hide the back of the mouth portion. Therefore, the mouth can be inspected with high accuracy and high efficiency.

  FIG. 1 shows a plan view of an inspection system including a mouth inspection device according to the present invention. The inspection system 1 includes a pair of mouth inspection devices 4 disposed on both sides of a conveyance line 3 that linearly conveys the containers 2 at regular intervals. The container 2 is a preform for forming a PET bottle. However, the inspection apparatus 4 of the present invention is not limited to a preform and can be applied to various containers having a mouth portion. The mouth portion 5 of the container 2 is provided with a thread as an uneven portion for attaching a screw type cap. The pair of mouth inspection devices 4 are installed away from each other in the conveyance direction of the container 2 (the direction of arrow A in FIG. 1). Each mouth inspection device 4 inspects the mouth 5 of the container 2 transported by the transport line 3 by a half turn to the left and right with the transport line 3 as a boundary. The mouth inspection devices 4 have the same configuration. Hereinafter, the details of one mouth inspection device 4 will be described.

  FIG. 2 shows an enlarged view of the mouth inspection device 4. FIG. 3 shows a state in which the mouth inspection device 4 of FIG. 2 is viewed in the transport direction. The mouth inspection device 4 is emitted from the illumination device 6 that illuminates the mouth 5 of the container 2, the back reflector 7 that reflects the light emitted by the illumination device 6 toward the mouth 5, and the mouth 5. An optical system 8 that guides light along a predetermined optical path, an optical filter 9 as filter means that selectively transmits or absorbs the light guided by the optical system 8, and a light that passes through the filter 9 and receives the light. And an imaging device 10 as imaging means for capturing an image of the unit 5. The inspection target area 5a of the mouth 5 to be inspected by the mouth inspection device 4 is a half circumference on the right side (right side in FIG. 2) with respect to the transport line 3.

  As shown in FIG. 4, the lighting device 6 includes a housing 11 installed above the outer periphery of the mouth 5 (upper side in FIG. 4), a light source 12 provided on the inner peripheral surface 11 a of the housing 11, And a top reflector 13 that covers the upper end 11b. The housing 11 has a ring shape larger than the mouth portion 5, and the inner peripheral surface 11 a is formed in a tapered surface shape that gradually increases in diameter from the upper end 11 b to the lower end 11 c of the housing 11. The light source 12 emits illumination light 14 having a wavelength for exciting the outer peripheral surface of the mouth portion 5 toward the mouth portion 5. For example, when the mouth portion 5 is formed of polyethylene terephthalate, which is a raw material for PET bottles, the illumination light from the light source 12 only needs to include a wavelength of 405 nm. A black light can be used as the light source 12 having such a wavelength. The top reflector 13 reflects the illumination light 14 emitted from the light source 12 toward the mouth 5. Therefore, the illuminating device 6 functions as direct illumination that irradiates the mouth portion 5 with the illumination light 14 from the light source 12 and indirect illumination that irradiates the mouth portion 5 with the reflected light of the illumination light 14 from the top reflector 13. Have

  The back reflector 7 is provided on the opposite side of the mouth 5 with respect to the inspection target region 5a, that is, on the back 5b (the left half of the conveyance line 3 in FIG. 2). The back reflector 7 includes an arcuate portion 7a that curves along the back surface 5b of the mouth portion 5, and a flat plate-like holding portion 7b that projects laterally from both ends of the arcuate portion 7a. The inner peripheral surface of the arc-shaped portion 7 a is formed as a mirror surface that reflects the illumination light of the illumination device 6. That is, the illumination light 14 emitted from the light source 12 is folded back by the back reflector 7 and enters the mouth part 5 as transmitted light 15 from the back surface 5b side with respect to the mouth part 5. The holding part 7 b is connected to the movable part 30 a of the holding mechanism 30 for the back reflector 7. The movable part 30a of the holding mechanism 30 incorporates a screw mechanism, for example, and moves the movable part 30a in a direction orthogonal to the transport direction of the transport line 3 by a predetermined operation. Thereby, the back reflector 7 is supported by the holding mechanism 30 in a state where the distance to the mouth portion 5 can be adjusted.

  The optical system 8 has a pair of side reflectors 17 that reflect the excitation excitation light 16 at the mouth 5 in the optical axis direction of the imaging device 10, and the excitation light 16 reflected by each side reflector 17 toward the imaging device 10. A pair of front reflectors 18 that are folded back, and a front reflection that is disposed on the optical axis of the imaging device 10 and that folds the transmitted light 15 transmitted through the mouth 5 and the excitation light 16 excited at the mouth 5 toward the imaging device 10. And a plate 19. The pair of side reflectors 17 are arranged on the inspection object region 5a side of the container 2 (see FIG. 2) and away from the container 2 in the transport direction (the direction of arrow B in FIG. 2). The pair of front reflectors 18 are disposed at positions farther from the container 2 toward the inspection object region 5 a than the side reflectors 17. The front reflector 19 is disposed opposite to the inspection object area 5a and at a position further away from the container 2 toward the inspection object area 5a than each front reflector 18.

  The filter 9 is provided between the container 2 and the front reflector 19 so as to face the front reflector 19. The filter 9 transmits the excitation light 16 excited at the mouth portion 5 and absorbs at least a part of wavelength region components other than the wavelength of the excitation light 16. The wavelength range absorbed by the filter 9 is the wavelength range itself (405 nm in the above example) of the illumination light 14 emitted from the illumination device 6 to the mouth 5. That is, the wavelength range of the illumination light 14 and the excitation light 16 excited by the illumination light 14 have different wavelength ranges, and the filter 9 absorbs the wavelength range of the illumination light 14 while exciting the excitation light 16. Is transmitted to the imaging device 10 through a wavelength range unique to the imaging device 10. However, the degree of absorption of the illumination light 14 by the filter 9 is set so that at least a part of the transmitted light 15 passes through the filter 9.

  The imaging device 10 is provided between the filter 9 and the container 2. The distal end 10 a of the imaging device 10 faces the filter 9. That is, the imaging device 10 is arranged with the shooting direction facing away from the container 5. On the distal end 10 a side of the imaging device 10, a light receiving unit 20 that receives the excitation light 16 and the transmitted light 15 that have passed through the filter 9 is provided. The imaging device 10 guides the excitation light 16 and the transmitted light 15 incident on the light receiving unit 20 to a CCD area sensor (not shown) disposed on a predetermined focal plane, and the inspection target region 5a of the mouth 5 is placed on the area sensor. An image is formed, and an image signal corresponding to the luminance distribution of the image is output.

  Next, the operation of the imaging apparatus 10 configured as described above will be described. The mouth 5 of the container 2 transported by the transport line 3 emits excitation light 16 and transmitted light 15 by the illumination light 14 from the illumination device 6. Excitation light 16 and transmitted light 15 emitted from the inspection target region 5 a of the mouth 5 enter the filter 9 via the optical system 8. The excitation light 16 and a part of the transmitted light 15 pass through the filter 9 and are received by the imaging device 10 to form an image of the entire inspection target region 5a. The imaging device 10 outputs an image signal corresponding to the brightness of the image. The inspection area 5a is inspected based on the captured image obtained from the image signal. After completion of the inspection, the container 2 is transported to the other mouth inspection device 4 by the transport line 3, and is similarly inspected using the back surface 5b of the mouth 5 as the inspection target region.

  According to the above mouth inspection device 4, the excitation light 16 generated at the mouth 5 is guided to the imaging device 10 while the filter 9 absorbs the wavelength band component of the illumination light 14 itself. The image of the inspection target region 5a of the mouth portion 5 obtained in (1) best represents the intensity distribution of the excitation light 16. When the specularly reflected light component of the mouth portion 5 with respect to the illumination light 14 is guided to the imaging device 10 as it is, even if the illumination light 14 is uniformly applied to the thread existing in the inspection target region 5a, the unevenness of the thread The specular reflection light is disturbed by the influence, and the shadow of the thread appears strongly in the image. However, regarding the excitation light 16, the excitation light 16 is emitted almost uniformly regardless of the concave portion or the convex portion and guided to the imaging device 10 as long as the unevenness of the thread is evenly illuminated by the illumination light 14. Therefore, the image acquired by the imaging apparatus 10 has no effect of the screw thread or even if it appears, the effect is considerably small. Moreover, the influence of the screw thread behind the inspection target area 5a does not appear as well. Accordingly, the filter 9 transmits the excitation light 16 while absorbing the specular reflection component from the mouth 5, thereby obtaining an image of the mouth 5 in which the influence of the screw thread existing in the mouth 5 is suppressed. Can do. In addition, when a defect such as a scratch or a foreign object exists on the surface of the inspection target region 5a, the excitation state of the excitation light changes due to the defect, and the influence appears in the image acquired by the imaging device 10. As a result, it is possible to clearly distinguish between a normal part and a defective part on the surface of the inspection target area 5a, and the mouth part 5 can be inspected with high accuracy. Further, since it is not necessary to insert an inspection jig such as a bush into the container 2, there is no need to temporarily stop or decelerate the conveyance line 3 at every inspection. Therefore, the mouth portion 5 of the container 2 can be efficiently inspected without affecting the transport efficiency of the transport line 3.

  Further, when a defect exists in the inside of the mouth part 5 or the inner peripheral surface, the transmitted light 15 is disturbed by the defect. Since the image acquired by the imaging device 10 also reflects the influence of the transmitted light 15, it is possible to detect these defects and foreign matters without overlooking them.

  Furthermore, in said form, the illumination range of the opening part 5 by the reflected light from the back surface reflecting plate 7, and its illumination intensity are changed by adjusting the distance of the back surface reflecting plate 7, the mouth part 5, and the back surface reflecting plate 7. Thereby, the influence of the transmitted light 15 on the image acquired by the imaging apparatus 10 can be changed. For this reason, the inspection by the transmitted light 15 can be realized at the same time without hindering the detection of the defect by the excitation light 16 which is the original purpose, and the inspection accuracy and reliability of the mouth 5 can be improved.

  Further, in the above embodiment, since the mouth inspection device 4 inspects the mouth 5 half by half with the pair of inspection devices 4 arranged on both sides of the conveyance line 3, the imaging device 10 is inspected every time inspection is performed. On the other hand, it is not necessary to rotate the mouth portion 5 and position it in the circumferential direction. This also increases the inspection efficiency. Since the imaging device 10 is arranged with the photographing direction facing away from the mouth portion 5, there is no possibility that the illumination light of the illumination device 6 directly enters the imaging device 10.

This invention is not limited to the form mentioned above, It can implement with a various form. For example, the illumination device only needs to have a shape that uniformly illuminates illumination light from various directions with respect to the inspection target region of the mouth, and the housing may be formed in a bowl shape. It may not be provided on the entire outer periphery of the part. The light source does not necessarily have to be provided over the entire inner peripheral surface. A lower surface reflector that reflects illumination light from the light source from the lower side to the mouth part may be provided below the mouth part, or lower illumination that irradiates illumination light from the lower side to the mouth part. An apparatus may be provided. The number and arrangement position of the reflection plates included in the optical system can be changed as appropriate.

  In the above embodiment, wavelength band components other than the wavelength of the excitation light are excluded by the optical filter 9, but the filter means is not limited to this. For example, when the imaging device outputs an image signal corresponding to the frequency spectrum of the incident light, a wavelength band component other than the wavelength of the excitation light from the image signal output from the imaging device instead of or in addition to the filter 9 By providing an electrical filter that excludes at least a part of the above, the influence of the wavelength region components other than the wavelength of the excitation light on the image may be excluded.

1 is a plan view of an inspection system including a mouth inspection device according to one embodiment of the present invention. The top view of the mouth part inspection apparatus which concerns on one form of this invention. The figure which looked at the mouth part inspection apparatus of Drawing 2 in the conveyance direction. The figure which shows a mode that an illuminating device irradiates illumination light to a mouth part, and a mouth part inject | emits light.

Explanation of symbols

2 Container 4 Mouth Inspection Device 5 Mouth 6 Illumination Device 7 Back Reflector 8 Optical System 9 Filter 10 Imaging Device 14 Illumination Light 16 Excitation Light

Claims (4)

An illumination device that is disposed along at least a portion of the mouth of the container and that irradiates the mouth with illumination light including a wavelength that excites the mouth;
Imaging means for receiving excitation light generated at the mouth and acquiring an image of the mouth formed by the excitation light;
Filter means for eliminating the influence of at least a part of the wavelength region components other than the wavelength of the excitation light on the image;
Equipped with,
The imaging means is arranged with the imaging direction opposite to the mouth, and an optical system for guiding excitation light from the mouth to the imaging means is arranged between the imaging means and the illumination device. Mouth inspection device characterized by being. The mouth inspection apparatus according to claim 1, wherein the filter means includes an optical filter that transmits the excitation light and absorbs at least a part of a wavelength band component other than the wavelength of the excitation light.   A back reflector for reflecting the illumination light toward the mouth is provided on the back side of the mouth with respect to the inspection target area of the mouth by the imaging means, and the filter means is the back reflector. 2. The influence of wavelength components other than the wavelength of the excitation light on the image is excluded in a range in which a part of the transmitted light reflected and transmitted through the mouth is reflected in the image. The mouth inspection apparatus according to 2.   The mouth inspection apparatus according to claim 3, wherein a distance between the mouth and the back reflector is adjustable.

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