JP2009025131A - Method and device for inspecting pinhole of can - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and device for inspecting a pinhole of a can capable of enhancing the reliability of inspection. <P>SOLUTION: The output of a light detecting sensor 1 for measuring the quantity of light within a can 15 in the ON-OFF timing of light sources 16 and 18 is detected during a period when the opening part of the can 15 passes the light detection surface of the light detecting sensor 1 by controlling the light sources 16 and 18 to alternately repeat the ON-OFF operation of the light sources 16 and 18 and, when the presence of the pinhole and the inspection abnormality of the pinhole are detected, abnormality is determined in the case where the lighting of the light sources 16 and 18 is not detected by the lighting confirming sensor 6 provided outside the can 15 when a control signal for bringing the light sources 16 and 18 to an ON state is sent out. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pinhole inspection method for a can, wherein in the step of manufacturing a can by forming an aluminum (alloy) plate or the like, a defective can is detected by detecting a pinhole in the formed can and an abnormality of the pinhole inspection is detected. And an inspection apparatus.

The pinhole inspection device uses a method of irradiating the can with light from the outside, detecting the light leaking inside with a sensor facing the opening of the can, and determining the presence or absence of the pinhole based on the detected amount It has been. For example, the pinhole inspection apparatus described in Patent Document 1 controls the light source that irradiates the can while the opening of the can passes through the inspection region of the sensor, and the light inside the can when the light source is on and off. The measurement is performed a plurality of times, and the presence or absence of a pinhole and the abnormality of the pinhole inspection are detected by a combination of determination results as to whether or not the measured value exceeds the threshold value. On the other hand, light generated by a light emitting diode is used as light that can be easily detected. The life of the light emitting diode is shortened by Joule heat generated by its own resistance, but this pinhole inspection device suppresses heat generation and extends the life by blinking the light emitting diode.
JP 2004-294369 A

  By the way, in the above-mentioned pin pole inspection device, in the case of a defective can having a pinhole, the light from the light source passes through the pinhole and enters the inside of the can, and is detected by a sensor. Judging. Therefore, if no light can be detected inside the can, it is determined that the can is good without a pinhole. Therefore, if the light source stops emitting light due to a failure, etc. Even if a defective can having a hole is an object to be inspected, there is a problem that light is not detected in the inside of the can, so that it is erroneously determined as a good can.

  In view of such circumstances, the present invention does not determine that a defective can is a good can because the light does not reach the interior when the light source breaks down, and can improve the reliability of inspection. An object is to provide a hole inspection method and an inspection apparatus.

In order to solve the above-described problems, the present invention proposes the following means.
That is, in the pinhole inspection method for a can according to the present invention, the light source is controlled to be turned on and off alternately, and the light source is turned on while the can opening passes through the light receiving surface of the light detection sensor. In the can pinhole inspection method for detecting the presence or absence of pinholes and pinhole inspection abnormalities by detecting the output of the light detection sensor that measures the amount of light inside the can at the OFF timing, and turning on the light source When the control signal to be transmitted is transmitted, if the lighting of the light source cannot be detected by a lighting confirmation sensor provided outside the can, it is determined that an abnormality has occurred.

  Even though a lighting confirmation sensor is provided outside the can that directly receives irradiation from the light source, and the control signal for turning on the light source is sent to turn on the light source, When it is not possible to detect the lighting of the light source, the light source is determined to be abnormal. As a result, it is possible to prevent a defective can from being misjudged as a good can when the light source fails and does not light up, and when the light detection sensor does not detect light inside the can, this is a failure of the light source. It is possible to quickly detect that it is caused by

  Further, the pin hole inspection method of the can according to the present invention includes ON and OFF of the light source detected by a lighting confirmation sensor provided outside the can, ON of the light source inside the can by the light detection sensor, It is characterized in that it is determined that the pinhole inspection is abnormal when there is a deviation in the timing of detection of the amount of light corresponding to OFF.

  If there is a difference between the light source ON / OFF timing and the sensor output detection timing and the light does not reach the inside through the pinhole, it is detected that it is due to the timing difference, so there is a pinhole Judgment of non-defective cans as good products is suppressed, and the reliability of inspection can be improved.

  The can pinhole inspection apparatus according to the present invention includes a light source that is alternately turned ON and OFF, and a light amount inside the can at the ON and OFF timing of the light source while the opening of the can passes through the light receiving surface. In the can pinhole inspection apparatus that detects the presence or absence of a pinhole based on the output of the light detection sensor, when sending a control signal to turn on the light source, It is characterized in that lighting confirmation means for judging that the light source is not turned on is abnormal.

  In addition, the pinhole inspection apparatus according to the present invention detects a timing difference between ON and OFF of the light source and detection of the amount of light corresponding to ON and OFF of the light source inside the can by the light detection sensor. A timing abnormality detection unit, the timing abnormality detection unit sending a light source ON / OFF timing, a lighting control circuit for lighting the light source based on the timing from the timing circuit, and the lighting confirmation unit; And a discrimination circuit for discriminating a difference between the lighting timing of the light source detected by the sensor and the timing transmitted from the timing circuit.

  According to the pinhole inspection method and inspection apparatus for a can according to the present invention, when the light source is detected by a lighting confirmation sensor provided outside the can, the light does not reach the inside when the light source fails. Therefore, it is possible to avoid a mistake in inspection when the light source fails, and to improve the reliability of the inspection.

  Embodiments of a can pinhole inspection method and inspection apparatus according to the present invention will be described below with reference to the drawings. 1 is a schematic diagram of a longitudinal section of a pinhole inspection apparatus according to the present invention, FIG. 2 is a diagram showing a configuration of a pinhole inspection method according to the present embodiment, and FIG. 3 is a diagram for explaining the flow of pinhole detection processing, FIG. 4 is a diagram for explaining the output waveform and output level detection of the sensor. The can to be inspected is inspected by, for example, a pinhole inspection apparatus as shown in FIG.

  As shown in FIG. 1, a can 15 to be inspected is placed on can fixing portions of star wheels (conveying mechanisms) 19 and 20, and the bottom of the can is held by a spindle 17. The turret 13 and the star wheels 19 and 20 convey a plurality of cans while being rotated by the shaft 21. The star wheel 19, 20 rotates to convey the can 15, and the light detection sensor 1 detects the light inside the can 15 during the time when the opening of the can 15 passes the light receiving surface of the light detection sensor 1.

    The light source 16 is provided so as to extend parallel to the shaft 21 and irradiates the upper outer peripheral surface of the can 15. The light source 18 is provided so as to extend in a direction perpendicular to the shaft 21 and the lower outer peripheral surface of the can 15. Is being irradiated. In addition, the light sources 16 and 18 are formed by arranging LEDs connected in series and having a high response speed, and are configured so that the outer peripheral surface of the can 15 can be irradiated with light uniformly. Further, a lighting confirmation sensor 6 is provided at a position that does not block the irradiation of the can 15 by the light sources 16 and 18 and is irradiated with light from the light sources 16 and 18 outside the can 15. In addition, in order to increase the light detection accuracy inside the can 15, a seal 14 attached to the turret 13 and a seal 12 attached to the support portion 11 of the light detection sensor 1 are provided, whereby the seal 12 and the turret are arranged. The light is prevented from leaking from the sliding portion between the two.

  As the light detection sensor 1, an optical sensor such as a photomultiplier tube is used. The light detection sensor 1 is inserted into a can from a pinhole generated in a can formed by deep drawing or squeezing and squeezing a metal plate. It detects weak light that has passed through and light leakage from the light detection part. Then, the detected signal is amplified, and after the high frequency component is removed through the time constant circuit, it is output to the discrimination circuit 2 shown in FIG.

  The discrimination circuit 2 has a role of discriminating whether or not the output level of the light detection sensor 1 exceeds a preset threshold value. The discriminating circuit 2 detects the output of the light detection sensor 1 a plurality of times in response to a timing command of a timing circuit 3 to be described later within the time when the opening of the can to be inspected passes through the light receiving surface of the light detection sensor 1. Comparison with the threshold is performed. The light sources 16 and 18 are also controlled to repeat the ON and OFF states with the same time width based on the timing command of the timing circuit 3, and the discrimination circuit 2 is in each of the ON and OFF states. A timing command is received from the timing circuit 3 so as to detect the output of the light detection sensor 1 at the center of the time width, for example. The timing for detecting the output of the light detection sensor 1 in this way is not limited to the center but may be anywhere as long as it is within the time width ranges of ON and OFF. Further, the ON / OFF time width is appropriately set according to the speed of the star wheels 19 and 20 that hold and transport the can 15 and the section in which the can 15 is transported.

  The timing circuit 3 detects the output of the light detection sensor 1 in the discrimination circuit 2 and sends a timing command for determining the timing for comparing the output level with the threshold value, and controls the light sources 16 and 18 to the illumination control circuit 4. A timing command is sent. That is, the timing circuit 3 sends a timing command for repeatedly turning on and off the light sources 16 and 18 to the illumination control circuit 4 at a certain timing, and the light sources 16 and 18 are turned on to the discrimination circuit 2. For example, at the center of each time width in the OFF state, a timing command for operating the output detection of the light detection sensor 1 and comparing with the threshold value is transmitted.

  The illumination control circuit 4 outputs a control signal for controlling ON and OFF to the light sources 16 and 18 according to a signal input from the timing circuit 3, and is controlled so that the light sources 16 and 18 are turned on or off. A signal indicating that the lighting is on is sent to the lighting lighting confirmation circuit 5.

  As the light detection sensor 1, an optical sensor such as a photomultiplier tube is used as the lighting confirmation sensor 6. The lighting confirmation sensor 6 is arranged corresponding to each of the light sources 16 and 18 outside the can to be inspected. Is output to the lighting lighting confirmation circuit 5. The lighting lighting confirmation circuit 5 compares the signal indicating that the light sources 16 and 18 sent from the lighting control circuit 4 are controlled to be in the ON state or the OFF state and the output of the lighting confirmation sensor 6. Thus, the light sources 16 and 18 have a role of confirming whether the light sources 16 and 18 are normally turned on or off so as to correspond to the control signal from the illumination control circuit 4. At this time, the output level of the lighting check sensor 6 does not reach the output level when the light source is turned on, even though the illumination control circuit 4 sends a control signal to be turned on to the plateaus 16 and 18. In this case, it is determined that an abnormality has occurred in the light sources 16 and 18, and the illumination lighting confirmation circuit 5 issues a device stop signal.

  Further, the illumination lighting confirmation circuit 5 is configured so that the light sources 16 and 18 are normally lit based on the control signal of the illumination control circuit 4, that is, the lighting confirmation sensor 6 is activated according to the signal from the illumination control circuit 4. When the output level is appropriate, a signal indicating the ON or OFF state of the light sources 16 and 18 is sent to the discrimination circuit 2 based on the output of the lighting confirmation sensor 6. The lighting lighting confirmation circuit 5 and the lighting confirmation sensor 6 constitute a lighting confirmation means 9.

  In addition to the above-described role, the discrimination circuit 2 detects the output from the light detection sensor 1 based on a signal indicating the ON state or OFF state of the light sources 16 and 18 from the illumination lighting confirmation circuit 5, and detects the detected value and the threshold value. It is judged whether the time of the total of three detection / comparison operations is within the time widths of the respective states corresponding to ON, OFF, ON of the light sources 16, 18, and either detection / comparison is performed. If it is recognized that the operation is not within the time width of the ON or OFF state of the corresponding light source 16, 18, the three operations of the discrimination circuit 2 and the ON, OFF, ON state of the light source 16, 18 Is judged to be abnormal, and an abnormal signal is output. The discrimination circuit 2, the timing circuit 3, the illumination control circuit 4, and the lighting confirmation means 9 constitute a timing abnormality detection means 10.

    In addition, when the operation of the discriminating circuit 3 and the timing of ON, OFF, ON of the light sources 16 and 18 are normal, the memory circuit 7 compares the detected value of the discriminating circuit 2 with the threshold value. Is stored, and the storage processing circuit 8 outputs a control signal for processing the can based on the determination result read from the storage circuit 7.

  FIG. 4 is a diagram showing an output signal of the light detection sensor 1 attached to the above-described pinhole inspection apparatus. The light detection sensor 1 is highly sensitive, has dark current and residual noise, and outputs a signal 30 shown in FIG. 4A when there is no light input. P is a threshold value for determining whether or not there is light from a pinhole. The time Ta-Tb is the time until the can 15 moves and enters the inspection region of the light detection sensor 1, and Tb-Te is the time that the can 15 is within the inspection region of the light detection sensor 1. Te-Tf is the time until the can 15 leaves the inspection area of the light detection sensor 1 and the next can enters the inspection area.

  When the can 15 has a pinhole, the output signal of the light detection sensor 1 has a waveform 31 shown in FIG. As shown in the figure, the output level of the light detection sensor 1 exceeds the threshold P at times Tb-Tc and Td-Te when the light sources 16 and 18 are ON. At the time Tc-Td when the light sources 16 and 18 are turned off, the output level becomes equal to or less than the threshold value P. The determination circuit 2 detects the output level of the light detection sensor 1 at times Tb-Tc, Tc-Td, and Td-Te at times t1, t2, and t3 and compares it with a threshold value P. When the output level exceeds the threshold value P, the signal “1” is output. When the output level is equal to or lower than the threshold value P, the signal “0” is output.

    Next, the operation of the present embodiment will be described with reference to FIGS. FIG. 2 is a diagram showing a flow of processing of the pinhole inspection of the can. First, the timing circuit 3 controls the illumination control circuit 4 so that the can 15 is in the inspection area of the light detection sensor 1 for the time Tb-Tc, and the light sources 16 and 18 are turned on and turned off at Tc. Sends a timing command to perform Further, a timing command for turning Td ON and Td-Te ON is sent, and the illumination control circuit 4 sends a control signal for turning on and off the light sources 16 and 18 based on this timing command (step 10). ).

  The illumination control circuit 4 sends a signal indicating that the light sources 16 and 18 are controlled to be in an ON state or an OFF state to the illumination lighting confirmation circuit 5 simultaneously with the control signals to the light sources 16 and 18. Based on this signal, the illumination lighting confirmation circuit 5 confirms the lighting of the light sources 16 and 18 which are inspection illuminations (step S11). That is, when the output level of the lighting confirmation sensor 6 has not reached the output level at the time of lighting the light source even though the signal indicating that the light sources 16 and 18 are controlled to be turned on is received. Determines that the light sources 16 and 18 are abnormal, sends a device stop signal, and stops the operation of the device (step S12). On the other hand, when there is no abnormality in the light sources 16 and 18 and the light sources 16 and 18 are normally lit by the control signal of the illumination control circuit 4, the apparatus is not stopped and the illumination lighting confirmation circuit 5 determines. A signal indicating that the light sources 16 and 18 are in an ON state or an OFF state is sent to the circuit 2 based on the output of the lighting confirmation sensor 6.

  The light detection sensor 1 detects and amplifies the light inside the can 15 in a state where the light sources 16 and 18 are controlled, and outputs the light after removing the high frequency component (step S13). Then, the determination circuit 2 detects the output of the light detection sensor 1 at times t1, t2, and t3 based on the timing signal supplied from the timing circuit 3 (step S14). At this time, the determination circuit 2 detects the output of the light detection sensor 1 based on the timing command as compared with a signal from the illumination lighting confirmation circuit 5 indicating that the light sources 16 and 18 are in the ON state or the OFF state. It is determined whether the times t1, t2, and t3 are within the time widths in the three states of ON, OFF, and ON, respectively (step 15). That is, the determination circuit 2 determines whether or not the timing of detection of the output of the light detection sensor 1 and the timing of ON, OFF, and ON of the light sources 16 and 18 are normal.

  For example, in the case shown in FIG. 4C, there is a deviation in the lighting timing of the light sources 16 and 18, and the output of the light detection sensor 1 is usually output while the light sources 16 and 18 are lit in the ON state. Since the light sources 16 and 18 are not lit at the detection timings t1 and t3, the illumination lighting check circuit 5 receives a signal indicating that the light sources 16 and 18 are in the OFF state. At this time, the discriminating circuit 2 outputs an abnormal signal because there is a difference between the detection timing of the output of the light detection sensor 1 and the timing when the light sources 16 and 18 are turned ON, OFF, and ON, and proper inspection cannot be performed. Then, a process in the case of an abnormal inspection is performed (step S16).

  On the other hand, when the output of the light detection sensor 1 is detected and the timings when the light sources 16 and 18 are turned on and off are normal, the detected values of the output of the light detection sensor 1 at times t1, t2, and t3 are set as threshold values. Compare with Po (step S17). When there is no pinhole in the can, the output of the light detection sensor 1 becomes the waveform 30 shown in FIG. 4A, the comparison result becomes “0” at time t1, t2, and t3, and the signal “000” is output. The When the can has a pinhole, the output of the light detection sensor 1 has a waveform 31 shown in FIG. 4B, and a signal “101” is output.

  The storage circuit 7 stores the output signal of the determination circuit 2 (step S18). The memory processing circuit 8 reads out the discrimination results at the times tb, Te, t1, t2, and t3 stored in the memory circuit 7 (step S19), and discriminates the presence / absence of a pinhole based on the combination of the read signals (step S20). . If two or more of the read signals are “0”, it is determined that there is no pinhole in the can (step S20: YES), and a control signal for processing as a good can is output (step S21).

  On the other hand, when “1” is two or more, it is determined that the pin has a pinhole or that there is an abnormality in the inspection (step S20: NO), and the process proceeds to step S22. In step S22, when the signal read from the memory circuit 7 is “101”, it is determined that there is a pinhole in the can and not an inspection abnormality (step S22: NO), and the control signal is processed as a defective can in step S19. Output.

  When there is a disturbance due to light leakage from the light detection portion, a defective holding state of the can 15, and the like, the inspection abnormal state is processed as follows in steps S20 and S22. The seal 12 prevents the light leakage from the sliding portion due to the rotation of the turret 13, but light leakage may occur depending on the deterioration of the seals 12 and 14 and the holding state of the can 15. The output waveform of the light detection sensor 1 when light leakage occurs is as shown by the waveform 33 in FIG. In this case, even when the light sources 16 and 18 are OFF (Tc−Td), light exceeding the threshold Po leaks due to disturbance from the inspection environment, and the output of the determination circuit 2 becomes “111”.

  The memory processing circuit 8 reads this signal “111” from the memory circuit 7 and determines in step S20 that there is a pinhole or that there is a test abnormality. Furthermore, in step S22, since the signal is “111”, it is determined that there is a disturbance such as light leakage and the inspection is abnormal (step S22: YES), and processing in the case of the inspection abnormality is performed (step S22: YES). Step S23).

  As described above, in the pinhole inspection apparatus for cans of this embodiment, the lighting confirmation sensor 6 is provided outside the can that is directly irradiated by the light sources 16 and 18 to light the light sources 16 and 18. When the lighting control circuit 4 sends a control signal for turning on the light sources 16 and 18, the lighting confirmation sensor 6 cannot detect the lighting of the light sources 16 and 18. The light source 16 or 18 is determined to be abnormal, and the apparatus itself is stopped. Therefore, even if the light detection sensor 1 does not detect light inside the can 15 and the discrimination circuit 2 outputs the signal “000”, it can be quickly confirmed that this is due to the failure of the light sources 16 and 18. Since it is possible to detect and stop the apparatus, it is possible to prevent an increase in inspection mistakes and improve the reliability of inspection.

  Further, as shown in FIG. 4C, even when the ON and OFF timings of the light sources 16 and 18 are deviated due to, for example, a malfunction of the timing circuit 3, the determination circuit 2 operates at times 1t and t2. Since it is possible to determine that the light source 16, 18 is ON or OFF at t3, it is possible to determine that the light source is abnormal. Can improve

  As mentioned above, although the pinhole inspection method and inspection apparatus of the can which are embodiments of the present invention have been described, the present invention is not limited thereto, and can be appropriately changed without departing from the technical idea of the present invention. is there.

It is the schematic of the longitudinal cross-section of a pinhole inspection apparatus. It is a figure which shows the structure of the pinhole detection part by embodiment of this invention. It is a figure explaining the flow of a pinhole detection process. It is a figure explaining the output waveform and output level detection of a sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light detection sensor 2 Discrimination circuit 3 Timing circuit 4 Illumination control circuit 5 Illumination lighting confirmation circuit 6 Illumination confirmation sensor 9 Illumination confirmation means 10 Timing abnormality detection means 15 Can

Claims (4)

The light source is controlled to be turned ON and OFF alternately, and the amount of light inside the can at the ON and OFF timing of the light source is measured while the can opening passes through the light receiving surface of the light detection sensor. In the pinhole inspection method of the can that detects the output of the light detection sensor and detects the presence or absence of a pinhole,
When a control signal for turning on the light source is sent, if the lighting confirmation sensor provided outside the can does not detect the lighting of the light source, it is determined as abnormal. Can pinhole inspection method.   There is a difference in timing between ON / OFF of the light source detected by the lighting confirmation sensor provided outside the can and detection of the light amount corresponding to ON / OFF of the light source inside the can by the light detection sensor. 2. The can pinhole inspection method according to claim 1, wherein it is determined that the pinhole inspection is abnormal. A light source that is alternately turned ON and OFF, and the light detection sensor that measures the amount of light inside the can at the ON and OFF timing of the light source while the opening of the can passes through the light receiving surface, In a pinhole inspection device for a can that detects the presence or absence of a pinhole based on the output of a light detection sensor,
A can pinhole inspection apparatus, comprising: a lighting confirmation means for judging that the light source is not turned on when a control signal for turning on the light source is sent. Timing abnormality detection means for detecting a timing deviation between ON and OFF of the light source and detection of the amount of light corresponding to ON and OFF of the light source inside the can by the light detection sensor;
The timing abnormality detection means includes
A timing circuit for sending the light source ON / OFF timing;
An illumination control circuit for lighting the light source based on the timing from the timing circuit;
The can pin according to claim 3, further comprising: a determination circuit that determines a difference between a lighting timing of the light source detected by the lighting confirmation unit and a timing transmitted from the timing circuit. Hall inspection device.

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