JPH09203712A - Detector of neck part of can - Google Patents

Abstract

PROBLEM TO BE SOLVED: To optically detect a defect in a neck part of a can by photographing a reflected light from a mirror by a CCD camera which is provided in the upper part of a light projecting part in concentric with the light projecting part. SOLUTION: A projected light from a ring light projecting part 5 is incident on the whole circumference of a neck part 4 of a can 1. The incident light on the neck part 4 by this projecting light is reflected here, and further reflected on a reflection face 8a of a ring mirror 8 so as to be incident on the CCD camera. When the can 1 approaches to the bottom of the ring mirror 8 so as to be concentric with the mirror 8, it is photographed by the CCD camera. A recessed part 4bL in the neck 4 which is an inwardly recessed curved surface extends in the intermediate part of a projecting curved surface 4a. Therefore, the bottom end part 4b of the recessed part 4b is formed into a curved change part changing from the recessed curved surface to the projecting curved surface so that an image of this part is reflected brighter than other parts. In a signal processing part, when a point brighter than an adjoining part is present on a circumference where the projecting curved surface 4a is reflected, it is thus detected to have a recess.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for optically inspecting the appearance of a can, and more particularly to a device for optically inspecting the neck of a can for defects.

[0002]

2. Description of the Related Art Some beverage cans have a mouth having a diameter smaller than that of a body and a tapered neck between the mouth and the body. The intersection of the neck and the body is a curved surface. There are rare cases in which the neck part is elongated and recessed. The lower end of the recess extends to the middle of the curved surface. Since the dented product is a defective product, it must be removed, and an inspection device for this purpose has been demanded.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide an apparatus for optically inspecting a neck portion of a can for defects.

[0004]

To achieve the above object, the present invention is an apparatus for inspecting a can having a tapered neck for a longitudinal recess in the neck of the can. A ring-shaped light projecting part that allows light to enter the entire outer surface of the neck from diagonally above, and concentric with the light projecting part under the light projecting part, inclined so as to reflect light reflected from the neck upward. A ring-shaped mirror having a reflecting surface, a CCD camera provided above the light projecting unit and concentrically with the light projecting unit for photographing reflected light from the mirror, and the brightness of the photographed light are compared on the circumference. It consists of a signal processing unit, and when the can comes under the ring-shaped mirror and becomes concentric with the mirror, it is photographed, and when there is a point that appears brighter than the brightness of nearby points on the circumference, it is judged that there is a dent. It is characterized by.

According to the present invention, the light that has entered the neck of the can from the ring-shaped light projecting portion is reflected by the surface of the neck portion and further reflected by the ring-shaped mirror to enter the camera. Since the lower end of the neck is a convex curved surface that bulges outward, the diffusion of reflected light is large, and the image is dazzled by the camera. The concave portion of the neck portion is a concave curved surface that is concave inward, and the concave portion extends to the middle of the convex curved surface. Therefore, the lower end of the recess is an inflection part that changes from a concave curved surface to a convex curved surface,
Since it is a small plane, the diffusion of reflected light is small,
It looks brighter than other parts. Therefore, the brightness is compared on the circumference where the convex curved surface of the lower end of the neck is reflected, and when there is a point that appears brighter than the neighboring points, it is determined that there is a depression.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a can neck inspection device according to the present invention will be described below with reference to FIGS. FIG. 1 is a cross-sectional view showing the overall structure of an inspection device for the neck of a can. In FIG. 1, reference numeral 1 is a beverage can. The can 1 has a body 2 and a mouth 3 having a diameter smaller than the diameter of the body 2.
A tapered neck portion 4 is provided between the and the body portion 2.

A ring-shaped light projecting portion 5 is arranged above the can 1, and the light projecting portion 5 is connected to a light source 7 via an optical fiber 6. The light from the light source 7 is guided to the light projecting section 5 by the optical fiber 6, and the light projecting from the light projecting section 5 enters the entire outer surface of the neck section 4 of the can 1 obliquely from above.

Below the light projecting portion 5, a ring-shaped mirror 8 having an inclined reflecting surface 8a is arranged concentrically with the light projecting portion 5. The mirror 8 is configured to reflect the reflected light from the neck portion 4 upward by the reflecting surface 8a. A CCD camera 9 is arranged above the mouth portion 3 of the can 1 so as to be concentric with the light projecting portion 5, and the reflected light from the mirror 8 is photographed. The CCD camera 9 is connected to the signal processing unit 10.

Next, the operation of the inspection device for the neck portion of the can constructed as described above will be explained with reference to FIGS. FIG.
FIG. 3 is an enlarged cross-sectional view of the main part of the inspection device for the neck of the can, and FIG. 3 is a diagram schematically showing an image of the neck 4 of the can 1 taken.

As shown in FIG. 2, the light projected from the ring-shaped light projecting portion 5 is incident on the entire circumference of the neck portion 4 of the can 1. The light that has entered the neck portion 4 by this light projection is reflected here, and further reflected by the reflecting surface 8a of the ring-shaped mirror 8 and enters the CCD camera 9. When the can 1 comes below the ring-shaped mirror 8 and becomes concentric with the mirror 8, an image is taken by the CCD camera 9. The image of the neck 4 of the can 1 taken is as shown in FIG. 3, and the parts of the neck 4 shown in FIG. 2 correspond to the parts of the image of FIG. The image of the neck portion 4 is the inside of the circumference and the outside of the circumference of the neck 4 are reversed.

FIG. 3 shows the brightness of each part. Since the lower end portion (between −) of the neck portion 4 of the can 1 has a convex curved surface 4a which bulges outward as shown in FIG. 2, diffusion of reflected light is large, and an image in this portion has a dull brightness. It is

As shown in FIG. 2, the recess 4b of the neck portion 4 is a recessed curved surface that is recessed inward, and the recess 4b extends partway into the convex curved surface 4a. Therefore, the dent 4
The lower end portion 4b _L of b is an inflection portion that changes from a concave curved surface to a convex curved surface, and since it is a small flat surface, the diffusion of reflected light is small, and as shown in FIG. It appears brighter than the part. Therefore, in the signal processing unit 10, the brightness is compared on the circumference where the convex curved surface 4a of the lower end portion of the neck 4 is reflected, and when there is a point that appears brighter than a nearby point,
It is determined that there is a dent.

[0013]

As described above, according to the present invention,
It is possible to inspect whether or not the neck portion of the can having the tapered neck portion has a vertical recess. Moreover, this inspection can be performed by one camera, and a simple device configuration can be achieved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of an inspection device for a neck portion of a can according to the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is an image of a neck portion of a can taken.

[Explanation of symbols]

 1 Can 4 Neck 4a Convex Curved Surface 4b Recess 5 Projector 7 Light Source 8 Mirror 9 CCD Camera 10 Signal Processor

Claims (1)

[Claims] 1. A device for inspecting whether or not a neck portion of a can having a tapered neck portion has a vertical recess, which is a ring-shaped projection for allowing light to be incident obliquely from above on the entire outer surface of the neck portion of the can. A light-shaped part, a ring-shaped mirror provided under the light-emitting part and concentric with the light-emitting part, and having a reflecting surface inclined so as to reflect the light reflected from the neck upward, and a light-emitting part above the light-emitting part. A CCD camera that is concentric with the light unit and captures the light reflected from the mirror;
It consists of a signal processing unit that compares the brightness of the photographed light on the circumference, and when the can comes under the ring-shaped mirror and becomes concentric with the mirror, it is photographed, and the brightness of neighboring points on the circumference Even if there is a point that appears bright, it is determined that there is a dent, the inspection device for the neck of the can.