JP6454913B2 - Inspection method for cap having bridge and inspection device for the cap - Google Patents

Description

  The present invention relates to a method and apparatus for inspecting the quality of a bridge in a cap attached to a container.

  A cap called a pilfer-proof cap is frequently used as a cap that is attached to the mouth of a container such as a beverage container. In a beverage container filling line in which this type of cap is used, it is determined whether or not the bridge connecting the skirt and the proof band is broken in order to prove that the cap after filling is not opened. Bridge break inspection has been carried out. As an inspection apparatus used for such a bridge inspection, for example, an inspection apparatus having a configuration in which a cap is illuminated with a mirror box camera while illuminating the cap from the top side (for example, a patent) Reference 1). In addition to the illumination on the top surface side, while illuminating the cap with a plurality of illumination units arranged around it, the peripheral surface of the cap is shared by a plurality of cameras arranged substantially at the same position as each illumination unit. In some cases, an inspection apparatus configured to take a picture is used.

JP 2005-189167 A

  Conventional caps are colored in various colors such as red and blue, and the materials used are highly light-shielding resins, so they are connected via the cap bridge by using the inspection device described above. Accurately inspects the quality of the bridge by acquiring an image with a sufficient contrast between the gap between the skirt and the proof band (hereinafter sometimes referred to as the gap near the bridge). It was possible to do. However, in recent years, there are increasing examples of adopting a transparent cap that is thin and translucently colored or non-colored and has a relatively high diffusibility of illumination light. When this type of cap bridge is to be inspected using conventional methods, the illumination light incident on the cap from the top side of the cap or the back side of the camera is diffused in the cap, and the gap between the peripheral surface of the cap and the vicinity of the bridge The difference in brightness from the part is reduced. Therefore, there is a possibility that the inspection accuracy cannot be sufficiently increased.

  Therefore, an object of the present invention is to provide an inspection method or the like that can accurately inspect the quality of a bridge of a cap having transparency.

  The inspection method for a cap according to one aspect of the present invention includes a procedure for illuminating the cap (5) attached to the mouth (4) of the container (3) and a procedure for photographing the peripheral surface of the illuminated cap. A method for inspecting the quality of a bridge in the cap based on an image obtained in the photographing procedure, wherein the illumination procedure is performed from the same side as the side on which the cap is photographed. Illumination light is irradiated on the cap, and the cap is not irradiated with illumination light from a side different from the side where the cap is photographed, or illumination whose illumination is limited to be lower than illumination light from the same side The illumination for the cap is set so that light is illuminated.

  According to the inspection method of the above aspect, the cap is illuminated from the same side as the side where the cap is photographed, and the cap is not illuminated from a different side, or the illuminance of the illumination light is limited to be low. In the case of photographing a cap having a cap, it is possible to suppress the influence of the illumination light that is incident on the cap from the top side of the cap or from the back side when viewed from the photographing direction in the cap. As a result, a sufficient difference in brightness between the peripheral surface of the cap and the gap near the bridge can be secured, and the quality of the bridge can be inspected with high accuracy.

  In one form of the inspection method according to the above aspect, the photographing procedure is repeated a plurality of times while sequentially changing the photographing direction (arrows D1 to D4 in FIG. 1) with respect to the cap, and the illuminating procedure is the photographing direction. Depending on the change, the direction in which the illumination light from the same side is irradiated may be sequentially changed a plurality of times. According to this, it is possible to shoot by dividing the peripheral surface of the cap into a plurality of times.

  In the above embodiment, the photographing procedure and the illuminating procedure may be repeated a plurality of times while the container is being conveyed. According to this, the peripheral surface of the cap can be photographed in a plurality of times without stopping the container.

  In the inspection method according to the above aspect, illumination means including a plurality of side illumination units (12A to 12D) arranged so that the cap can be illuminated from mutually different sides in the circumferential direction is installed to illuminate the cap. In the procedure, among the plurality of side illumination units (12A to 12D), an illumination unit (12A as an example) that can irradiate illumination light from the same side as the side where the cap is photographed is turned on. The illuminating means is arranged so that the illumination light is not irradiated on the cap from a side different from the illumination light by the illumination unit, or illumination light whose illuminance is limited to be lower than illumination light from the same side. You may control. According to this, the side illumination unit that can irradiate illumination light from the side where the cap is photographed is turned on, and the other illumination units are turned off, or the illumination means is limited so that the illuminance of the illumination light is limited to be low. By performing the control, the above-described shooting procedure and illumination procedure can be repeated a plurality of times.

  In the inspection method according to the above aspect, the illuminating unit is installed so as to further include an upper illumination unit (10) capable of illuminating the cap from the top surface (5a) side in addition to the plurality of side illumination units, In the illuminating procedure, a side illumination unit (12A as an example) that can irradiate illumination light from the same side as the side where the cap is photographed is turned on, and from a side different from the illumination light by the side illumination unit. A first illumination state that controls the illumination means such that illumination light is not irradiated on the cap or illumination light whose illumination intensity is limited to be lower than illumination light from the same side is illuminated (for example, FIG. 3A), the upper illumination unit is turned on, and the cap is not irradiated with illumination light from the side different from the illumination light from the upper illumination unit, or the upper illumination unit is not illuminated. The second illumination state (for example, the state of FIG. 3B) for controlling the illumination means is switched according to the transparency of the cap so that illumination light whose illumination intensity is limited to be lower than illumination light by the unit is illuminated. You may do it. According to this aspect, when inspecting a transparent cap that may reduce accuracy in the conventional inspection method, the first illumination state is selected, and the peripheral surface of the transparent cap and the vicinity of the bridge It is possible to ensure a sufficient difference in brightness from the gap portion and to inspect the quality of the bridge with high accuracy. On the other hand, when inspecting a cap with high light shielding properties, the quality of the bridge can be inspected with the same accuracy as in the past by selecting the second illumination state.

  In the inspection method according to the above aspect, in the illuminating procedure, illumination light from the same side as the side where the cap is imaged is used as the imaging optical axis when the cap is imaged (dashed line L1 in FIG. 1). To L4) may be irradiated in a direction inclined obliquely toward the cap from a position biased toward the top surface (5a) or the lower edge (5c) of the cap. According to this, the illumination light is incident obliquely from the top surface side or the lower edge side of the cap, so that the illumination light can be more effectively blocked from entering the gap near the bridge. Therefore, the difference in brightness between the peripheral surface of the cap and the gap near the bridge is enlarged, and the inspection accuracy can be further increased.

  The inspection apparatus (1) for a cap according to one aspect of the present invention includes a plurality of caps (5) arranged so as to photograph the peripheral surfaces of the cap (5) attached to the mouth (4) of the container (3) from different directions. The photographing units (11A to 11D) and the respective photographing units can be irradiated with illumination light from the same side as the side where the cap is photographed, and are associated with each of the plurality of photographing units. The lighting means including the plurality of side lighting units (12A to 12D) arranged and the shooting timing of each of the plurality of shooting units are controlled so that the peripheral surfaces of the cap are sequentially shot from different directions. When the cap is photographed by any one photographing unit (11A as an example), from the same side as the side where the cap is photographed by the one photographing unit. A side illumination unit that can irradiate bright light (12A as an example) is turned on, so that illumination light is not irradiated to the cap from a side different from the illumination light by the side illumination unit, or from the same side And a control means (15) for controlling illumination by the illumination means so that illumination light whose illuminance is lower than that of the illumination light is limited.

  According to the inspection apparatus of the above aspect, when the cap is photographed by one photographing unit, the side illumination unit on the same side as the photographing unit photographing the cap is turned on, and the other illumination units are The light is turned off or the illumination intensity of the illumination light is limited to be low. Therefore, illuminate the cap from the same side as the image is taken, and do not illuminate the cap from a different side, or set the relationship between the shooting direction and the illumination direction so that the illuminance of the illumination light is limited low However, the peripheral surface of the cap can be photographed in multiple steps. Therefore, a sufficient difference in brightness between the peripheral surface of the cap and the gap in the vicinity of the bridge in the image acquired in each shooting can be ensured, and thereby the quality of the bridge can be accurately inspected.

  In the inspection apparatus according to the above aspect, each of the plurality of imaging units may shoot the cap at different imaging positions (P1 to P4) set at intervals on the conveyance path of the container. It may be arranged. According to this, by photographing the cap with the photographing unit every time the container reaches the photographing position, it is possible to photograph the peripheral surface of the cap in multiple times without stopping the container.

  In the inspection apparatus according to the above aspect, the illumination unit further includes an upper illumination unit (10) capable of illuminating the cap from the top surface (5a) side in addition to the plurality of side illumination units, and the control unit The side illumination unit (12A as an example) that can irradiate illumination light from the same side as the side where the cap is photographed is turned on, and the cap is applied to the cap from a side different from the illumination light by the side illumination unit. A first illumination state (for example, the state of FIG. 3A) in which the illumination means is controlled such that illumination light is not irradiated or illumination light whose illuminance is limited to be lower than illumination light from the same side is illuminated. And the upper illumination unit is turned on, and the cap is not illuminated with illumination light from a side different from the illumination light from the upper illumination unit, or illumination light by the upper illumination unit The (state of e.g., FIG. 3B) a second illumination condition for controlling the illuminating means and may be provided to switchably as illumination light remote illumination is limited to a low is illuminated. According to this aspect, when inspecting a permeable cap that may reduce accuracy in the conventional inspection apparatus, the first illumination state is selected, and the peripheral surface of the permeable cap and the vicinity of the bridge It is possible to ensure a sufficient difference in brightness from the gap portion and to inspect the quality of the bridge with high accuracy. On the other hand, when inspecting a cap with high light shielding properties, the quality of the bridge can be inspected with the same accuracy as in the past by selecting the second illumination state.

  In the inspection apparatus according to the above aspect, each of the plurality of side illumination units may be arranged on the top surface (5a) side of the cap with respect to the photographing optical axis of the photographing unit (dashed lines L1 to L4 in FIG. 1). You may provide at least 1 illuminating lamp (14a, 14b) arrange | positioned so that the said illumination light may be irradiated in the direction inclined diagonally toward the said cap from the position biased to the lower edge (5c) side. According to this, it is possible to make the illumination light incident obliquely from the top surface side or the lower edge side of the cap, thereby more effectively blocking the illumination light from entering the gap near the bridge. Therefore, the difference in brightness between the peripheral surface of the cap and the gap near the bridge is enlarged, and the inspection accuracy can be further increased.

  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 inspection method of the present invention, the cap is illuminated from the same side as the side where the cap is photographed, and the cap is not illuminated from a different side, or from the same side. Since the illumination for the cap is set so that illumination light whose illumination intensity is lower than that of the illumination light is illuminated, even if the cap has transparency, the peripheral surface and the gap portion near the bridge It is possible to ensure a sufficient difference in brightness and to accurately inspect the quality of the bridge. Further, according to the inspection apparatus of the present invention, the peripheral surface of the cap can be imaged in a plurality of times while setting the relationship between the imaging direction and the illumination direction in accordance with the above inspection method. A sufficient difference in brightness between the peripheral surface of the cap and the gap in the vicinity of the bridge in the image to be captured can be ensured, thereby accurately inspecting the quality of the bridge.

The top view of the inspection apparatus used with the inspection method concerning one form of the present invention. The figure which shows the positional relationship of the container opening part in an inspection apparatus, an illumination unit, and an imaging | photography unit. The timing chart which shows the imaging | photography time in each imaging | photography unit and the illumination timing of an illumination unit in the case of test | inspecting the cap which has permeability | transmittance. The timing chart which shows the imaging | photography time in each imaging | photography unit in the case of test | inspecting the cap which has light-shielding property, and the illumination time of an illumination unit. The top view of the inspection apparatus which concerns on a modification. FIG. 6 shows an example of an image acquired by an inspection method according to one embodiment of the present invention. The figure which shows an example of the image acquired with the test | inspection method which concerns on a comparative example.

  Hereinafter, an inspection method according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2 show an example of an inspection apparatus applicable to a bridge inspection method. The inspection device 1 is provided on a transport path by the transport conveyor 2. The conveyor 2 conveys PET bottles (hereinafter abbreviated as bottles) 3 as an example of containers to be inspected in a predetermined direction (arrow A direction) at equal intervals. The bottle 3 is not rotated and is transported in a state of being placed in a fixed posture. In FIG. 1, the conveyance direction is set linearly, but a curved section may be set in the conveyance path of the conveyor 2, and the inspection apparatus 1 may be arranged in the curved section.

  The bottle 3 carried into the inspection apparatus 1 is filled with contents such as beverages. As apparent from FIG. 2, a cap 5 is attached to the mouth 4 of the bottle 3. The cap 5 includes a top surface 5a, a substantially cylindrical skirt 5b extending downward from the outer periphery of the top surface 5a, and a proof band 5c disposed below the skirt 5b. This is a so-called pilfer-proof type cap having a configuration in which a plurality of bridges (not shown) are connected to the band 5c. The cap 5 may be formed of an appropriate material, but in the following, the cap 5 is formed as a transparent cap that is semi-transparent colored or non-colored and has a relatively high diffusibility to illumination light. Continue the explanation as if Here, the transparency refers to the property of transmitting illumination light in the visible wavelength range. Whether the cap 5 is transmissive or not can be determined by using a cap having a light-shielding property to obtain a sufficient image for the bridge inspection by the conventional illumination method, and for the bridge inspection by the conventional illumination method by diffusion of illumination light. What does not provide a sufficient image may be distinguished as a transparent cap.

  As shown in FIG. 1, the inspection apparatus 1 includes a ring-shaped upper illumination unit 10 arranged to illuminate the inspection area S on the conveyor 2 from directly above, and the inspection area S laterally with respect to the conveyance direction. The four photographing units 11A, 11B, 11C, and 11D arranged on the side of the conveyance path so as to be sandwiched between them, and the four side illumination units arranged in alignment with the photographing units 11A to 11D 12A-12D. Each of the upper illumination unit 10 and the side illumination units 12 </ b> A to 12 </ b> D is provided as illumination means for the cap 5. The photographing units 11A to 11D include a camera including a solid-state image sensor such as a CCD or a CMOS. Each of the imaging units 11A to 11D shoots by sharing approximately 1/4 each of the entire circumference of the cap 5 attached to the bottle 3, and converts the obtained optical image into an image signal and outputs the image signal.

  When the inspection units 1 are viewed from above, the imaging units 11 </ b> A to 11 </ b> D are configured such that each imaging optical axis (indicated by the alternate long and short dash lines L <b> 1 to L <b> 4 in FIG. Is arranged. However, the photographing positions P <b> 1 to P <b> 4 of the photographing units 11 </ b> A to 11 </ b> D are shifted at equal intervals with respect to the transport direction of the transport conveyor 2. Hereinafter, the photographing units 11A to 11D are referred to as first to fourth photographing units 11A to 11D according to the numbers attached to the corresponding photographing positions P1 to P4, and the photographing units 11A to 11D are distinguished from each other. When there is no need to do this, it may be referred to as the photographing unit 11. Similarly, the side lighting units 12A to 12D may be referred to as first to fourth lighting units 12A to 12D, or may be referred to as lighting units 12.

  The first photographing unit 11A photographs the cap 5 when the center of the bottle 3 reaches the photographing position P1, and the second photographing unit 11B photographs the cap 5 when the center of the bottle 3 reaches the photographing position P2. The third photographing unit 11C photographs the cap 5 when the center of the bottle 3 reaches the photographing position P3, and the fourth photographing unit 11D performs the cap 5 when the center of the bottle 3 reaches the photographing position P4. Shoot. The photographing directions of the photographing units 11A to 11D are parallel to the optical axes L1 to L4 as indicated by arrows D1 to D4 in FIG. Until the first photographing unit 11A starts photographing and the fourth photographing unit 11D finishes photographing, the bottle 3 is continuously conveyed at a predetermined speed without stopping. The intervals between the shooting positions P1 to P4 are set such that the time length required for the bottle 3 to move between adjacent shooting positions is longer than the time length required for shooting the cap 5 by one shooting unit 11. Is set. That is, the intervals between the photographing positions P1 to P4 are set so that the periods during which the caps 5 are photographed by the photographing units 11 do not overlap each other. In FIG. 1, the intervals of the photographing positions P1 to P4 are exaggerated, and the actual interval may be about several mm.

  As shown in FIG. 2, the illumination unit 12 includes an upper illumination lamp 14a and a lower illumination lamp 14b. Each of the upper illumination lamp 14a and the lower illumination lamp 14b is a cap from the same side as the side where the cap 5 is imaged by the corresponding imaging unit 11 when the inspection apparatus 1 is viewed from above (the state of FIG. 1). 5 is arranged so that illumination light can be irradiated. For example, when the cap 5 is used as a reference, the illuminating lights 14a and 14b of the first illumination unit 12A associated with the first imaging unit 11A are from the same side as the side where the first imaging unit 11A is provided. It arrange | positions so that illumination light may be irradiated toward. The illumination light is visible light. For example, the illumination lamps 14a and 14b irradiate white light using a white LED as a light source as illumination light. The same applies to the wavelength range of the illumination light and the light source of the upper illumination unit 10.

  As is clear from FIG. 2, when the inspection apparatus 1 is viewed from the side of the cap 5, the upper illumination lamp 14 a is on the top surface 5 a side of the cap 5 with respect to the photographing optical axes L <b> 1 to L <b> 4 by the photographing unit 11. It arrange | positions so that illumination light may be irradiated in the direction which inclined diagonally downward toward the cap 5 from the position biased to. On the other hand, the lower illumination lamp 14b is inclined obliquely upward toward the cap 5 from a position deviated toward the lower edge of the cap 5, that is, the proof band 5c side with respect to the photographing optical axes L1 to L4 by the photographing unit 11. It arrange | positions so that illumination light may be irradiated. 2 shows the relationship between the first photographing unit 11A and the fourth photographing unit 11D and the corresponding first illumination unit 12A and fourth illumination unit 12B, the second photographing unit 11B and the third photographing unit. The relationship between the unit 11C and the second lighting unit 12B and the third lighting unit 12C corresponding to them is the same as that in FIG.

  As shown in FIG. 1, the inspection apparatus 1 is provided with a control unit 15 that controls the imaging operation of the imaging unit 11 and the illumination operations of the illumination units 10 and 12. The control unit 15 controls the photographing operation of the photographing unit 11 so that the cap 5 is photographed sequentially at the photographing positions P1 to P4. In addition, when any one of the photographing units 11 is in the photographing period, the control unit 15 turns on only the illumination lamps 14 a and 14 b of the illumination unit 12 associated with the photographing unit 11 and turns on the other photographing units 11. The illumination timing of the illumination unit 12 is controlled so that all the illumination lamps 14a and 14b of the associated illumination unit 12 are extinguished. For example, the control unit 15 starts photographing by the first photographing unit 11A when the bottle 3 reaches the photographing position P1, and only the lighting lamps 14a and 14b of the first lighting unit 12A are lit, The operation of the illumination unit 12 is controlled so that the illumination lamps 14a and 14b of the four units 12B to 12D are all turned off. Further, while the cap 5 is sequentially photographed at the photographing positions P1 to P4, the control unit 15 keeps the upper illumination unit 10 in an extinguished state.

  FIG. 3A is a timing chart showing an example of on / off switching control for the operations of the upper illumination unit 10, the photographing unit 11, and the illumination unit 12 by the control unit 15 when the cap 5 having transparency is inspected. In FIG. 3A, “unit 1” corresponds to the first imaging unit 11A and the first illumination unit 12A, “unit 2” corresponds to the second imaging unit 11B and the second illumination unit 12B, and “unit 3” corresponds to the first The “unit 4” corresponds to the fourth photographing unit 11D and the fourth lighting unit 12D, corresponding to the third photographing unit 11C and the third lighting unit 12C. “On” means that the photographing unit 11 performs photographing and the lighting lamps 14 a and 14 b of the lighting unit 12 are turned on. “Off” means that photographing by the photographing unit 11 is stopped and the lighting unit 12 is turned on. This means that the illumination lamps 14a and 14b are turned off. The time t1 is the time when the bottle 3 has reached the photographing position P1, the time t2 is the time when the bottle 3 has reached the photographing position P2, the time t3 is the time when the bottle 3 has reached the photographing position P3, and the time t4 is the bottle 3 Indicates the time at which the shooting position P4 is reached.

  As apparent from FIG. 3A, during the period from time t1 to t2, the first imaging unit 11A performs imaging while only the illumination light from the first illumination unit 12A is applied to the cap 5, and the time t2 to t3. Is taken with the second photographing unit 11B in a state where only the illumination light from the second illumination unit 12B is applied to the cap 5, and between the times t3 and t4, the illumination light from the third illumination unit 12C is taken. Is taken by the third photographing unit 11C in a state where only the cap 5 is irradiated, and after the time t4, the fourth photographing unit 11D is in a state where only the illumination light from the fourth illumination unit 12D is irradiated to the cap 5. Shooting is performed. That is, the control unit 15 repeats photographing by the photographing unit 11 a plurality of times while sequentially changing the photographing direction with respect to the cap 5, and sequentially changes the direction in which the illumination light is irradiated according to the change of the photographing direction. The operations of the photographing unit 11 and the illumination unit 12 are controlled so that the illumination by 12 is repeated a plurality of times. In addition, the upper illumination unit 10 is maintained in the extinguished state at every photographing of the cap 5. That is, at each photographing in FIG. 3A, the illumination by the illumination unit is controlled to the first state in which the cap 5 is illuminated only from the same side as the side where the cap 5 is photographed.

  The image signal output from each photographing unit 11 is provided to a predetermined image processing apparatus, and is subjected to necessary image processing and is used for determining whether the bridge is good or bad. For example, it is determined whether or not the bridge image is identified and cut. In that case, if the bridge is broken, the portion where the bridge should be present is displayed as a gap, and therefore, whether or not the bridge is broken is determined based on the state of the gap. For example, the total area of the gap portions (dark portions) in the obtained image is calculated, and if the area exceeds a predetermined reference value, it is determined that a bridge break has occurred. Note that the processing of the image signal output from the photographing unit 11 and the quality determination of the bridge may be executed by the control unit 15 or a computer device different from the control unit 15. The determination of the quality of the bridge may be performed by a method of simply determining the presence or absence of a gap or determining the size of the gap in the vertical direction (axial direction). In addition, the quality of the bridge may be inspected using an appropriate method.

  According to the above form, the illumination light of the illumination unit 12 is irradiated only from the same side as the side where the cap 5 is photographed, and the illumination light is not irradiated from other different sides. Therefore, when inspecting the bridge of the cap having transparency, the possibility that the illumination light enters from the top surface 5a side of the cap 5 and the back side of the cap 5 when viewed from the photographing unit 11 and diffuses inside the cap 5 is eliminated. can do. Therefore, a sufficient difference in brightness between the peripheral surface of the cap 5 and the gap near the bridge can be ensured, and the quality of the bridge can be inspected with high accuracy.

  When the cap 5 is formed of a colored material having high light shielding properties, the side illumination units 12A to 12D are turned off, and the cap 5 is photographed by the photographing unit 11 while the upper illumination unit 10 is turned on. do it. An example is shown in FIG. 3B. In the example of FIG. 3B, the photographing by the photographing unit 11 is sequentially performed. During that time, all the side illumination units 12 are turned off, and the illumination unit is controlled so that the upper illumination unit 10 is turned on at every photographing. . That is, at each photographing in FIG. 3B, the illumination by the illumination unit is controlled to the second state in which the cap 5 is illuminated only by the illumination light of the upper illumination unit 10. However, the upper illumination unit 10 may be continuously lit from the start of shooting by the first shooting unit 11A to the end of shooting by the fourth shooting unit 11D. Note that when shooting a light-shielding cap, it is not always necessary to sequentially change the shooting timing of the shooting units 11, and the caps 5 may be shot simultaneously by the four shooting units 11. In this way, by appropriately switching the lighting units 10 and 12 on and off according to the light shielding properties of the caps, both the transmissive cap and the light shielding cap can be inspected by the same inspection apparatus.

  This invention is not limited to the form mentioned above, You may implement in the form to which various changes or deformation | transformation were given. For example, in the above embodiment, when inspecting the cap 5 having transparency, only the side illumination unit 12 disposed on the same side as the side where the cap 5 is photographed by the photographing unit 11 is turned on, and the other Although the side illumination unit 12 and the upper illumination unit 10 are turned off, the side illumination arranged on the same side as the side where the cap 5 is photographed is provided as long as the brightness difference necessary for the bridge inspection is ensured. Illumination light whose illuminance is limited to be lower than the illumination light from the unit 12 may be emitted from at least one of the other side illumination units 12 and the upper illumination unit 10. As an example, when illuminating the cap 5 with illumination light from the side illumination unit 12 disposed on the same side as the side where the cap 5 is photographed by the photographing unit 11, the upper illumination unit 10 is turned on with low illuminance. You may let them. The inclination of the cap 5 can be inspected. Further, when inspecting the light-shielding cap, it is not limited to only the illumination from the upper illumination unit 10, as long as at least one of the side illumination units 12 is ensured to have a brightness difference necessary for bridge inspection, You may light up so that illumination intensity may be restrict | limited lower than the illumination light from the upper illumination unit 10. FIG.

  When only the cap 5 having transparency is to be inspected, the upper illumination unit 10 may be omitted. The number of the photographing units and the lighting units can be changed as appropriate, not limited to the example in which the four photographing units 11 and the lighting unit 12 are used to share the peripheral surface of the cap 5 for photographing. For example, as illustrated in FIG. 4, the inspection apparatus 1 may be configured so as to share and photograph the peripheral surface of the cap 5 using three imaging units 11A to 11C and illumination units 12A to 12C.

  In the inspection apparatus 1, each of the photographing unit 11 and the illumination unit 12 is disposed at a position other than that illustrated, and a mirror, a prism, and other optical members are appropriately disposed between the units 11 and 12 and the photographing positions P1 to P4. 1, the shooting direction and illumination direction of the cap 5 at each of the shooting positions P <b> 1 to P <b> 4 may be set to have a relationship as shown in FIG. 1.

  An example of an image obtained by photographing a translucent cap having transparency with the inspection apparatus 1 having the above-described configuration is shown in FIG. However, the image of FIG. 5 is a part of an image acquired by turning off the upper illumination unit 10 and operating the photographing units 11A to 11D and the side illumination units 12A to 12D according to the timing chart of FIG. 3A. In this example, a bridge break occurs at the location indicated by the arrow. In the example of FIG. 5, the cap skirt and the surface of the proof band are projected as bright portions, while the gap between them is projected as a dark portion, so that a bridge break can be detected relatively easily. On the other hand, as a comparative example, FIG. 6 shows an example of an image obtained by photographing the same cap with only the upper illumination unit 10 of the inspection apparatus 1 turned on and the side illumination units 12A to 12D turned off. In the image of FIG. 6, the brightness of the gap between the skirt and the proof band increases due to the diffusion of the illumination light, and the brightness difference between the peripheral surface of the cap and the gap near the bridge is considerably larger than that of FIG. It is shrinking. Therefore, it is difficult to detect even if a bridge break occurs in the arrow portion. A comparison between FIG. 5 and FIG. 6 shows that if the relationship between the photographing direction and the illumination direction is set according to the present invention, the quality of the bridge of the cap having transparency can be accurately inspected.

DESCRIPTION OF SYMBOLS 1 Inspection apparatus 2 Conveyor 3 Bottle (container)
5 cap 5a top surface of cap 5b skirt 5c proof band 10 upper illumination unit (illumination means)
11A, 11B, 11C, 11D Imaging unit 12A, 12B, 12C, 12D Side illumination unit (illumination means)
14a, 14b Illumination lamp 15 Control unit (control means)

Claims (4)

Including a procedure of illuminating a cap having transparency and attached to the mouth of the container, and a procedure of photographing the peripheral surface of the illuminated cap, based on the image obtained by the photographing procedure A cap inspection method for inspecting the quality of a bridge in a cap,
A plurality of photographing units are arranged so that the peripheral surface of the cap can be photographed from different directions, and illumination light can be irradiated to the cap from the same side where the cap is photographed in each photographing unit. Installing lighting means including a plurality of side illumination units arranged in association with each of the plurality of photographing units,
The imaging procedure is repeated a plurality of times by controlling the imaging time of each of the plurality of imaging units so that the peripheral surfaces of the cap are sequentially imaged from different directions, and at any one imaging unit When the cap is photographed, a side illumination unit capable of irradiating illumination light from the same side as the side where the cap is photographed by the one photographing unit is turned on, and the illumination light by the side illumination unit is By controlling the illumination by the illumination means so that illumination light is not irradiated on the cap from a different side, or illumination light with a lower illuminance than the illumination light from the same side is illuminated. A method for inspecting a cap that repeats the illumination procedure.   The cap inspection method according to claim 1, wherein the photographing procedure and the illuminating procedure are repeated a plurality of times while the container is being conveyed. In addition to the plurality of side illumination units, the illumination means is installed so as to further include an upper illumination unit capable of illuminating the cap from the top surface side,
In the illuminating procedure, a side illumination unit capable of irradiating illumination light from the same side as the side where the cap is photographed is turned on, and the cap is illuminated from a side different from the illumination light by the side illumination unit. A first illumination state in which the illumination means is controlled so that illumination light that is not irradiated with light or is limited in illumination intensity lower than illumination light from the same side is illuminated, and the upper illumination unit is turned on The illumination light is not irradiated on the cap from the side different from the illumination light by the upper illumination unit, or the illumination light with a lower illuminance than the illumination light by the upper illumination unit is illuminated. The cap inspection method according to claim 1, wherein the second illumination state for controlling the illumination unit is switched according to the permeability of the cap.   In the step of illuminating, a position where illumination light from the same side as the side where the cap is imaged is biased toward the top surface side or the lower edge side of the cap with respect to the imaging optical axis when the cap is imaged The method for inspecting a cap according to any one of claims 1 to 3, wherein irradiation is performed in a direction inclined obliquely toward the cap.