JP2016142670A - Laser type checkup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent or restrain checkup errors caused by abnormality of the radiating point of a laser beam.SOLUTION: A laser type checkup device is so configured that two laser type displacement sensors 13a and 13b are arranged in a direction orthogonal to a relative shifting direction at equal distances from a checkup object 1, sets of distance data in a same position in the shifting direction obtained by the laser type displacement sensors 13a and 13b are compared with each other and, if a deviation between the compared sets of distance data surpasses a prescribed reference value, the greater set of distance data is replaced with compensation data.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an apparatus for inspecting deformation or displacement of an inspection object by irradiating the inspection object with laser light and capturing reflected light.

  Measuring the distance to the object using laser light, processing the measured value to determine the amount of displacement or deformation, and further integrating the amount of displacement from the reference position to determine the area, etc. Conventionally known. As an example, laser light is used for the internal pressure inspection of a sealed can. The sealed container that is the object to be inspected is, for example, a canned food containing a lot of water or a beverage can filled with a beverage. In these sealed containers, the contents are filled in the container. Thereafter, it is known that the inside of the container is sealed in an airtight state. However, even if it is a metal sealed container, there is a possibility that outside air may enter the container due to the occurrence of a container abnormality such as a pinhole or winding failure. In addition, gas may be generated in the sealed container due to abnormal contents such as rot and deterioration of food. Such abnormalities may cause a situation in which the degree of vacuum in the container is reduced, or the internal pressure of the container is reduced due to leakage of internal gas. Therefore, in order to eliminate so-called defective products from the production line, laser beam irradiation is performed to inspect the deformation of the sealed container and the internal pressure that causes the deformation.

  The present applicant has already proposed an apparatus and a method for inspecting the internal pressure of a sealed container using laser light according to Japanese Patent Application Laid-Open No. H10-228707. The invention irradiates the lid with laser light, receives the reflected light with a displacement sensor, measures the amount of displacement in the container axial direction in a predetermined section of the lid, integrates the amount of displacement, and the bottom lid This is an internal pressure inspection device and method for a sealed container that calculates the cross-sectional area in the container axial direction in the predetermined section and determines the quality of the internal pressure based on the cross-sectional area.

JP 2013-96709 A

  The above-described inspection apparatus or method that uses laser light measures the distance, position, and the like to the object by receiving the laser light reflected by the object. Therefore, since the reflectance varies depending on the color and cleanliness of the surface irradiated with the laser light, the inspection accuracy is affected by the color and cleanliness of the surface. On the other hand, a character, a pattern, etc. may be attached | subjected to the surface of test objects, such as the sealed container mentioned above. In such an inspection object, when the irradiation point of the laser beam crosses a character or a pattern, the amount of light received by the sensor changes, which becomes an error or greatly affects the inspection result.

  For example, on the bottom lid of the above-described sealed container, the production number, the expiration date, and the expiration date are printed as a small set of dots with an ink jet printer or the like in black ink. It is customary to be implemented later. On the other hand, a red semiconductor laser of 650 nm is mainly used as the laser light, and this laser light has a property of being absorbed by black ink, and the laser light irradiated during the internal pressure inspection process is irradiated to the black ink portion. Then, it is absorbed here, and the reflected light quantity of the laser light decreases. FIG. 3 shows the results of an experiment conducted by the present inventors. Characters are printed with black ink on the bottom lid of the metal can, and the metal can is moved below the laser sensor at a constant speed. In this example, laser light reflected from the lid is received and a voltage corresponding to the amount of reflected light is output. The portion indicated by the symbol “E” in FIG. 3 is the portion of the character made of black ink, and appears as a deep valley on the graph representing the measurement result. Therefore, since this portion has a large amount of displacement from the reference position, the cross-sectional area of the space portion generated with the deformation has a large value. For this reason, in the case of a negative pressure container, it is determined that the internal pressure in the sealed container is lower than the actual pressure, and partial absorption of the laser light causes an erroneous inspection.

  The present invention has been made by paying attention to the above technical problem, and can avoid or suppress erroneous inspection caused by variation in optical properties or vibration of the surface irradiated with laser light. The object is to provide an inspection device.

  In order to achieve the above object, the present invention provides a laser beam that is reflected by irradiating the inspection object from the laser displacement sensor while moving the inspection object relative to the laser displacement sensor. Is a laser type inspection apparatus that acquires data of a distance between the laser type displacement sensor and the inspection object, and inspects the inspection object based on the acquired distance data, Two laser displacement sensors are arranged at the same distance from the object to be inspected in a direction orthogonal to the relative movement direction, and in the movement direction obtained by these laser displacement sensors. When the distance data at the same position are compared with each other and the deviation of the compared distance data exceeds a predetermined reference value, the compared distance data And it is characterized in that it is configured to replace the distance data showing a larger value of the data to the correction data.

  In the inspection apparatus of the present invention, the correction data may be distance data indicating a small value among the compared distance data or distance data prepared in advance as a normal value.

  In the inspection apparatus of the present invention, the inspection object is a sealed container in which at least one of an upper end portion and a lower end portion of the trunk portion is closed by a lid portion, and the distance data is the two distance data. The displacement measured by a laser displacement sensor is a displacement amount of a portion of the lid portion on the center side of the coupling portion integrating the lid portion with the body portion, and the correction data includes the deviation. For the measurement point that is larger than the reference value, a displacement value indicating a small value or a displacement value prepared in advance as a normal value, the displacement amount obtained by one laser displacement sensor and the other laser displacement The integrated value obtained by integrating the average value with the displacement obtained by the sensor, or the integrated value of the displacement obtained by one of the laser displacement sensors and the other laser. It may be configured to determine the acceptability of the internal pressure of the sealed container based on the average value of the integral values of the obtained displacement amount by Formula displacement sensor.

  According to the inspection apparatus of the present invention, when optical properties are partially changed, such as ink that absorbs laser light is attached, two distance data are acquired, and the distance between them is acquired. Since it is determined whether or not the deviation of the data exceeds the reference value, it is possible to determine the abnormality of one of the distance data. In that case, the partial data is not adopted and replaced with correction data. Data acquisition and erroneous inspection based on it can be avoided or suppressed.

It is the side view which showed typically an example which applied this invention to the internal pressure test | inspection apparatus of a sealed container. It is the top view which showed typically the internal pressure test | inspection apparatus in FIG. It is the graph which showed the amount of reflected light (displacement amount) in the measurement point of a horizontal axis with the voltage.

  The present invention is an apparatus that acquires distance data using laser light and inspects an object based on the distance data, and the inspection object is not particularly limited. The method of inspection based on the distance data is arbitrary. For example, any distance data is used as a reference value, a displacement amount is obtained by comparing the reference value with other distance data, and the absolute value of the displacement amount is large or small. It may be configured to perform inspection or determination based on the above, or may be configured to perform numerical processing such as integration on the distance data and perform inspection or determination based on the processed result Good.

  The present invention can be applied to the internal pressure inspection of a sealed container, and a specific example thereof will be described. The target sealed container is a container in which a body portion filled with contents is sealed in an airtight state by a lid portion. It's okay. More specifically, a so-called three-piece type container in which a canopy is attached to the upper end of the trunk and a bottom lid is attached to the lower end, a so-called two-piece type in which a canopy is attached to the upper end of the trunk formed integrally with the bottom. The container may be a bottle-type container in which a bottom lid is attached to the lower end portion of the body portion and a mouth neck portion having a screw portion at the upper end portion is integrally formed and a cap is screwed to the mouth neck portion. . The material of the container is not particularly limited, and may be aluminum, an alloy thereof, steel, or the like. The present invention can be applied to an internal pressure inspection for metal cans made of these metals. Further, the sealed container may be a negative pressure container whose internal pressure is lower than atmospheric pressure, or a positive pressure container whose internal pressure is higher than atmospheric pressure.

  FIG. 1 shows an example in which the internal pressure of the bottle-type can 1 is inspected. In the example shown here, the bottle-type can 1 filled with contents is inverted with its cap 2 on the lower side. It installs on the conveyor 3 in a state, and it is comprised so that an internal pressure test | inspection may be performed, conveying in the state. The bottle-shaped can 1 will be described more specifically. A bottom lid 5 is attached to one end portion (upper end portion in FIG. 1) of the metal barrel portion 4. The bottom cover 5 is formed in a substantially disk shape, and is attached to the body portion 4 by winding the outer peripheral flange portion 6 around the opening end of the body portion 4. This winding portion is a connecting portion between the body portion 4 and the bottom lid 5. An annular groove portion 7 called a counter sink is formed on the inner peripheral side of the flange portion 6 in the bottom cover 5, and the inner peripheral edge of the annular groove portion 7, that is, the protrusion of the inner peripheral inclined wall 8 in the annular groove portion 7. A portion that continues from the end (projecting end toward the bottom side of the bottle-shaped can 1) 9 to the inner peripheral side is a panel portion 10. In the example shown in FIG. 1, the panel portion 10 is bent in a dome shape toward the inside of the bottle-shaped can 1 with the protruding end 9 as a starting point. In addition, the bottle type can 1 in the example shown in FIG. 1 is configured as a negative pressure container whose internal pressure is lower than atmospheric pressure. Further, the other end portion (lower end portion in FIG. 1) of the body portion 4 is formed with a mouth neck portion 11 having a screw portion on the outer peripheral surface, and the cap 2 is screwed to the mouth neck portion 11. Yes.

  The conveyor 3 continuously conveys the bottle-shaped can 1 in an inverted state, and for example, a belt conveyor can be adopted. The conveyance speed can be set as appropriate, and may be, for example, about 70 m / min. A rotary encoder (not shown) is attached to the driving side or driven side roller or driving motor shaft of the conveyor 3, and the rotary encoder can detect the traveling speed and the traveling position of the conveyor 3. . Therefore, it is comprised so that the bottle-type can 1 on the conveyor 3 can be specified based on the traveling position information.

  Above the conveyor 3, above the pass line (passing position) of the bottom lid 5 in the bottle-shaped can 1 that is placed and conveyed in an inverted state on the conveyor 3, more specifically, on a plane parallel to the bottom lid 5 In addition, two laser displacement sensors (hereinafter simply referred to as displacement sensors) 13a and 13b are arranged. The displacement sensors 13a and 13b are configured to irradiate a laser beam toward the bottom lid 5 of the bottle-shaped can 1 being conveyed by the conveyor 3, capture the reflected light, and measure the distance. It is a thing of composition. The diameter on the laser light irradiation surface, that is, the spot diameter is preferably 30 μm or a diameter close thereto. Further, the laser light is repeatedly irradiated at a high speed. Therefore, each laser displacement sensor 13a, 13b is configured to continuously measure the distances to a number of positions (a number of points) on the bottom cover 5. That is, the displacement sensors 13a and 13b are configured to output laser pulses, and the repetition rate (pulse interval) is 500 times or more while the bottom cover 5 passes under the displacement sensors 13a and 13b. As described above, the speed is set so that the bottom lid 5 can be irradiated with laser light. Further, as shown in the schematic plan view of FIG. 2, the displacement sensors 13a and 13b are separated from the straight line passing through the center of the bottom lid 5 by a width B when the bottle-shaped can 1 passes below the displacement sensors 13a and 13b. Along the straight lines 16a and 16b, the laser beams are arranged in parallel at positions Da and Db (see FIG. 2). Since the ink used for printing a part of the bottom cover 5 is a very small point, the width B is set to 0.5 mm in this example.

  Above the conveyor 3, a sensor for detecting that the bottle-shaped can 1 has reached the internal pressure inspection start position is disposed. In the example shown in FIG. 1 and FIG. 2, two sets of photoelectric sensors 14a and 14b that detect the bottle-shaped can 1 in a non-contact manner are arranged on the sides of the region through which the body 4 passes, and each of them is irradiated. When the bottle-shaped can 1 blocks the light, it is detected that the bottle-shaped can 1 has reached the internal pressure test start position, and a detection signal is output. The relative positions of the photoelectric sensors 14a and 14b and the displacement sensors 13a and 13b described above are the positions where the body 4 first blocks the irradiation light of the photoelectric sensors 14a and 14b, and the tightening portion in the bottle-type can 1 The position is set at a position where the laser beam is irradiated to the front end in the transport direction or slightly outside. That is, the photoelectric sensors 14a and 14b are configured to detect the bottle-shaped can 1 and at the same time start measuring the distance from the displacement sensors 13a and 13b at the position of the front end side in the transport direction of the bottle-shaped can 1. Yes. The two displacement sensors 13a and 13b are shifted by a width C in the transport direction so that the reflected light of the laser light emitted from the displacement sensors 13a and 13b does not enter the respective displacement sensors 13a and 13b. Has been. In the case of this example, the width C is set to 2.6 mm, and accordingly, the photoelectric sensors 14 a and 14 b are also shifted by 2.6 mm from each other in the transport direction. The bottle-shaped can 1 on the conveyor 3 can be specified by the detection signals of the photoelectric sensors 14a and 14b and the detection signal of the rotary encoder.

  The rotary encoder and displacement sensors 13 a and 13 b and the photoelectric sensors 14 a and 14 b are connected to the controller 15. The controller 15 is mainly composed of a microcomputer, outputs a control signal to the rotary encoders and displacement sensors 13a and 13b and the photoelectric sensors 14a and 14b, receives a detection signal, and based on the detection signal. It is configured to perform a predetermined calculation and to control whether the internal pressure of each bottle-type can 1 is good or not, and to specify the bottle-type can 1 that has been determined to have poor internal pressure. An example of the control will be described below.

  The bottle-type cans 1 to be inspected are continuously placed on the conveyor 3 in the inverted state shown in FIG. 1, and are conveyed by the conveyor 3 with a predetermined interval between the bottle-type cans 1. When the predetermined bottle-shaped can 1 advances to the installation position of the photoelectric sensor 14a described above, the distance to the bottom lid 5 detected by the displacement sensor 13a is captured. Further, when the bottle-type can 1 advances to the installation position of the second set of photoelectric sensors 14b, the distance to the bottom lid 5 detected by the displacement sensor 13b is similarly taken. Thereafter, the bottle-shaped can 1 is conveyed at a constant speed, and each displacement sensor 13a, 13b intermittently outputs a laser pulse to measure the distance to measure the distance in two rows on the bottom lid 5 (each 500 points). The above distance is measured. And among these measured values, the deviation (relative displacement amount) of the distance between the predetermined reference location and other locations is calculated.

  In the embodiment described here, the reference location is the projecting end 9 which is the base point of the deformation of the panel unit 10 described above, and the measured value of the projecting end 9 and each of the center side from the measured value. The deviation from the measured value of the point is calculated. For such a reference location, for example, the distance in the transport direction between the forward end in the transport direction and the protruding end 9 in the transport direction in the body part 4 to which the photoelectric sensors 14a and 14b are sensitive is obtained in advance. The time from when the detection signal is output until the protruding end 9 reaches the position measured by the displacement sensors 13a and 13b may be obtained, and the measurement value at the time when the time has elapsed may be set as a location. Or since the measured value about the annular groove part 7 mentioned above becomes maximum, after that, a measured value becomes small and becomes the minimum in the protrusion end 9, It is good also considering the location which produces a minimum value in this way as a reference | standard location.

  Note that the end of the measurement may be determined by the passage of time determined from the distance between the protruding ends 9 before and after the panel portion 10 and the conveyance speed by the conveyor 3, or the data at the protruding ends 9 is minimal. Since it appears as a value, the measurement or the data capture may be terminated by detecting this minimum value.

  An example of the graph obtained by measuring as described above is shown in FIG. FIG. 3 is a graph in which the horizontal axis indicates 500 measurement points, and the vertical axis indicates the reflected light amount (displacement amount) as a measurement result at the measurement points with a voltage at which 20 scales indicate 1V. In this graph, the two rows of waveforms are shifted up and down for easy understanding.

  The obtained graph is overlapped within the controller 15 by being moved by 2.6 mm of the distance of the width C, which is a displacement between the displacement sensors 13a and 13b, and between the two protruding rows 9 at the front and rear. The displacement amounts are compared at corresponding measurement points, the displacement amounts (distance data of the present invention) are different from each other, and the deviation of the displacement amount exceeds a predetermined judgment reference value (for example, 0.1 V). In this case, the large displacement amount is deleted, and the displacement amount indicating the smaller value or the displacement amount set in advance as a normal value (correction data in the present invention) is used as the displacement amount of the measurement point. Integrate the average value of the displacement amount in the two rows, or find the integral value that averaged the integral value of the displacement amount in each row, and compare the integral value with the preset integral value (judgment reference value) The internal pressure of the bottle-type container 1 A constant. The correction data may be distance data obtained by the other displacement sensor or data obtained by processing the distance data, in addition to the distance data prepared in advance.

  As described above, the distance (displacement amount) measurement points by the displacement sensors 13a and 13b are a large number of points along the straight lines 16a and 16b parallel to the straight line passing through the center of the bottom cover 5, and therefore, the deviation of the measured value is different. The integrated value or the integrated value is a panel that is recessed inside the bottle-shaped can 1 and a straight line 16a, 16b that connects two points facing each other across the width B and a straight line (diameter) passing through the center of the protruding end 9. The area of the portion surrounded by the surface of the portion 10 is substantially meant. If the internal pressure of the bottle-type can 1 is within a normal range, the area value obtained in this manner falls within a predetermined range according to the internal pressure. On the other hand, if the internal pressure is high due to the generation of gas due to pinholes or deterioration of contents (if the negative pressure is insufficient), the amount of deformation of the panel section 10 will be reduced, so that the measurement is performed. The area value is smaller than the lower limit value defining the normal range. On the other hand, if the internal pressure of the bottle-type can 1 is excessively low, the amount of deformation of the panel portion 10 increases and the measured area value becomes larger than the upper limit value defining the normal range.

  Therefore, in the present invention, the area obtained as described above is compared with predetermined upper and lower limit values, and if it exceeds the normal range, it is determined that the internal pressure is poor. As described above, since the bottle-shaped can 1 on the conveyor 3 is specified by the detection value of the rotary encoder and the detection signals of the photoelectric sensors 14a and 14b, the bottle-shaped can determined as having an internal pressure failure as described above. Therefore, the bottle-shaped can 1 with poor internal pressure is removed from the conveyance line by a predetermined exclusion mechanism (not shown) on the downstream side in the conveyance direction on the conveyor 3.

  According to the present invention, as described above, since the integrated value or integrated value of the deformation amount of the lid portion and the internal pressure show a strong correlation, the integrated value or integrated value is compared with a reference value prepared in advance. The quality of the internal pressure can be accurately determined. In particular, since displacements at many locations are integrated or integrated, even if there is a slight deviation from the normal value at each measurement location, the amount of displacement when integrated or integrated increases, so accurate measurement of the amount of deviation is possible. Alternatively, it is possible to accurately determine the internal pressure. In addition, since the above device measures the amount of displacement using a laser beam with a small spot diameter, it is possible to accurately measure the amount of displacement at a number of locations on the lid, and in this respect also accurate internal pressure determination It can be performed. Further, since the measurement reference point of the displacement amount is the protruding end 9 described above, even if the bottle-shaped can 1 being transported is tilted and the posture is displaced, the measured point of the panel portion 10 that is deformed by the internal pressure. And the reference location are close to each other, the measurement error due to the deviation of the posture is reduced. And in this invention, since the average value of the displacement amount of 2 rows is integrated and the integration value or the average value of the integral value of each displacement amount is determined, the quality of the internal pressure of the bottle-type can 1 is determined. It has improved. Furthermore, since the two rows of displacement can be compared at each corresponding measurement point, if the laser beam is absorbed by the ink and the displacement of one side is excessively large, the large amount of displacement is deleted and a small value is set. The indicated displacement amount or a displacement amount prepared in advance as a normal value can be used as the displacement amount of the measurement point, and the determination accuracy is further improved.

  The present invention is not limited to the specific examples described above, and the sealed container to be inspected may be a canned container or a synthetic resin container other than a bottle-shaped can, and a negative pressure container in which a hollow deformation occurs due to internal pressure. It is not limited to this, and it may be a positive pressure (positive pressure) container in which expansion deformation occurs due to internal pressure. When targeting a positive pressure container, the center part of the lid part swells most and the amount of displacement associated with the expansion is obtained, so the reference part is the part of the lid part farthest from the displacement sensor. . Further, since the displacement sensor and the sealed container to be inspected need only be relatively moved when measuring the displacement, the sealed sensor may be fixed and the displacement sensor may be moved. And the reference | standard location for measuring or calculating the relative displacement amount in the test | inspection apparatus which concerns on this invention is not restricted to said protrusion end 9, The appropriate location in the said panel part 10 may be sufficient.

  DESCRIPTION OF SYMBOLS 1 ... Bottle type can, 2 ... Cap, 3 ... Conveyor, 4 ... Body part, 5 ... Bottom cover, 6 ... Flange part, 9 ... Projection end, 10 ... Panel part, 13a, 13b ... Displacement sensor, 14a, 14b ... Photoelectric sensor, 15 ... controller, 16a, 16b ... straight line, B ... width, C ... width, Da, Db ... position.

Claims (3)

The laser-type displacement sensor and the laser-type displacement sensor receive the laser light reflected from the laser-type displacement sensor and reflected from the laser-type displacement sensor. In the laser type inspection apparatus that acquires the data of the distance between the inspection object and inspects the inspection object based on the acquired distance data,
Two laser displacement sensors are arranged at the same distance from the object to be inspected in a direction orthogonal to the relative movement direction, and in the movement direction obtained by these laser displacement sensors. Comparing distance data at the same position, when the deviation of the compared distance data exceeds a predetermined reference value, the distance data showing a large value is replaced with correction data. A laser type inspection device characterized by that.   2. The laser inspection apparatus according to claim 1, wherein the correction data is distance data indicating a small value among the compared distance data or distance data prepared in advance as a normal value. The inspection object is a sealed container in which at least one of the upper end portion and the lower end portion of the trunk portion is closed by a lid portion,
The distance data is measured by the two laser displacement sensors, and is a displacement amount of a portion on a center side of the lid portion with respect to a coupling portion in which the lid portion is integrated with the trunk portion,
The correction data is a displacement amount prepared in advance as a displacement amount or a normal value indicating a small value for the measurement point where the deviation is larger than the reference value,
The integrated value obtained by integrating the average value of the displacement amount obtained by one laser displacement sensor and the displacement amount obtained by the other laser displacement sensor, or obtained by one laser displacement sensor. The internal pressure of the sealed container is determined based on an average value of an integrated value of the displacement amount obtained and an integrated value of the displacement amount obtained by the other laser displacement sensor. The laser type inspection apparatus according to claim 1.

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