JP4339271B2 - Metal detector - Google Patents

Description

  The present invention relates to a metal detection device that determines whether or not a material having metal properties such as an oxygen scavenger and silica gel is contained in an article being conveyed.

  2. Description of the Related Art Conventionally, a metal detection apparatus has been used that continuously conveys a plurality of articles that are inspection objects by a conveyor or the like, and detects a substance having a metal property contained in each article.

  For example, Patent Document 1 discloses an oxygen scavenger forgetting detection device that inspects an object in which a oxygen scavenger is encapsulated using a metal detector using the fact that the oxygen scavenger has a metal property. It is disclosed.

Patent Document 2 discloses a metal detection device that reduces the frequency of occurrence of malfunctions in a metal detection device by limiting the operation time for detecting a substance having a metal property to only during the passage of an article. .
Japanese Utility Model Publication Sho 62-111572 (published July 16, 1987) JP-A-8-211160 (released on August 20, 1996)

  However, the conventional metal detection apparatus has the following problems.

  That is, in the metal detector disclosed in the above publication, the interval between articles conveyed continuously is narrower than a predetermined interval, and the article being conveyed does not contain an oxygen scavenger and is close to the article. If the back article being transported contains an oxygen scavenger, the article being transported earlier will be erroneously determined to contain the oxygen scavenger due to the influence of the oxygen scavenger contained in the back article. There is a fear. On the other hand, even when the interval between articles conveyed continuously is equal to or less than a predetermined interval, the article being conveyed first contains oxygen scavenger, and the article behind does not contain oxygen scavenger. Under the influence of detecting the oxygen scavenger of the previous article, there is a risk that the back article will be erroneously determined to contain the oxygen scavenger.

  An object of the present invention is to provide a metal detection device capable of preventing an erroneously determined article from flowing downstream as it is when a plurality of articles that are continuously conveyed are conveyed close to each other. It is to provide.

  A metal detection device according to a first aspect of the present invention includes a transport unit, a metal detection unit, a determination unit, a storage unit, a distance detection unit, and a control unit. The transport unit continuously transports a plurality of articles to be inspected. A metal detection part detects the substance which has the property of the metal contained in the articles | goods conveyed by the conveyance part. The determination unit determines whether or not the article contains a substance having a metal property based on the detection result in the metal detection unit. The storage unit stores an appropriate interval between the articles conveyed in the conveyance unit. The interval detection unit detects the interval between the articles conveyed in the conveyance unit. A control part makes invalid the determination result in a determination part, when the detection result in an interval detection part is below the suitable space | interval memorize | stored in the memory | storage part.

  Here, in a metal detection device that inspects the presence or absence of a substance having a metal property for a plurality of articles that are continuously conveyed, the articles that have been conveyed within a preset appropriate interval are conveyed first. The determination of at least one of the received article and the article on the back side is invalidated.

  Here, the metal or the substance having a metal property includes a substance such as an oxygen scavenger and silica gel in addition to the metal itself. In addition, plastic bags filled with metal or substances with metal properties, soup in a bag made of aluminum foil (metal, one layer in a multilayer) or aluminum vapor deposition (metal) film, metal This includes small boxes with made bonuses. The interval between the articles means a distance between the rear end of the article conveyed first in the conveyance direction and the front end of the subsequent article. And the appropriate interval memorize | stored in a memory | storage part is an interval required in order to test | inspect the next article | item appropriately after inspecting the goods conveyed previously.

  Usually, a metal detection device that inspects the presence or absence of a substance having metallic properties while continuously conveying a plurality of articles performs a good inspection when each article is being conveyed while maintaining a predetermined interval. However, there is a possibility that an accurate inspection cannot be performed on the articles before and after being conveyed close to each other at a predetermined interval or less due to the mutual detection.

  Therefore, the metal detection device of the present invention includes a storage unit that stores in advance an appropriate interval between articles that can be accurately inspected, and an interval detection unit that detects an interval between articles being conveyed. And when the detection result in the interval detection unit is equal to or less than the appropriate interval, among the items conveyed in close proximity by the control unit at an appropriate interval or less, either of the front and rear items or both of the items The judgment result is invalid.

  Thereby, it is possible to prevent articles conveyed close to each other from flowing downstream while being erroneously determined. As a result, the accuracy of the inspection can be improved by re-inspecting the article for which the determination is invalid with a proper interval.

  A metal detection device according to a second aspect of the present invention is the metal detection device according to the first aspect of the present invention, wherein the determination unit determines that the product is a non-defective product when a substance having a metal property is included in the article.

  Here, the metal detection device of the present invention includes a substance having a metal property, such as an article containing an oxygen scavenger, in an inspection for detecting the presence or absence of mixing of a substance having a metal property. We use for inspection to confirm thing.

  In other words, in the inspection for confirming that the substance having the metal property is not mixed, the articles conveyed close to each other are both discharged as defective products mixed with the substance having the metal property. It doesn't matter. However, in an inspection for confirming that a substance having a metal property is mixed, there is a possibility that it is erroneously determined as a good product even though a substance having a metal property is not mixed.

  For this reason, by using a substance with a metal property as a non-defective product, it is invalidated for items that may be misjudged due to close transportation, and a re-inspection is carried out at an appropriate interval. Can do.

  A metal detection device according to a third aspect of the present invention is the metal detection device according to the first or second aspect of the present invention, wherein the control unit is configured to detect an article that has been transported first among articles that have been transported within an appropriate interval. When a substance having a metallic property is detected, the determination result of the subsequent article is invalidated.

  Here, when a substance having a metallic property is detected in an article that has been transported earlier with the interval of the article detected by the interval detection unit being equal to or less than a predetermined interval, the article is transported close to the article. Since the rear article may be affected by the detection of a metal substance contained in the previous article and cannot be accurately inspected, the determination result of the rear article is invalidated.

  As a result, when a material having a metal property is contained in a previous article that is transported in close proximity at an appropriate interval or less, a substance having a metal property remains erroneously detected in the subsequent article. Can be prevented. Therefore, highly accurate inspection can be performed by performing re-inspection in a state where an appropriate interval is provided.

  Note that the influence of detecting a substance having a metal property contained in an article conveyed in advance is, for example, a reaction of a detection signal that detects a substance having a metal property in a receiving coil constituting a metal detection unit. This is because a certain amount of time is required for the to return to the initial state. In other words, it was impossible to perform an accurate inspection even if the inspection of the back article was performed before the response of the detection signal that detected the metal property was returned, so the inspection was performed at an appropriate interval. The judgment result is assumed to be trusted only for the goods.

  A metal detection device according to a fourth aspect of the invention is the metal detection device according to the first or second aspect of the invention, in which the control unit determines the nature of the metal in the rear article among the articles conveyed within an appropriate interval. When a substance is detected, the determination result of the article conveyed first is invalidated.

  Here, in the case where the interval between the articles detected by the interval detection unit is equal to or less than the predetermined interval and a substance having a metal property is detected in the subsequent article, the substance having the metal property contained in the subsequent article is detected. Since there is a possibility that the inspection of the previous article cannot be accurately performed due to the detected influence, the determination result of the previous article is invalidated.

  This avoids the risk of false detection of a substance having a metal property in the previous article when a substance having a metal property is contained in a rear article that is transported in close proximity at an appropriate interval or less. it can. Therefore, a high-precision inspection can be performed by re-inspecting the previous article with a proper interval.

  A metal detection device according to a fifth invention is the metal detection device according to any one of the first to fourth inventions, wherein the metal detection unit includes a transmission coil that generates an alternating magnetic field and an alternating magnetic field. And a receiving coil arranged.

  Here, the detection signal in the receiving coil arranged in the alternating magnetic field generated by the transmitting coil is read to detect the substance having the property of metal contained in the article being conveyed.

  Thereby, it is possible to detect a substance having a metal property with a simple configuration.

  A metal detection device according to a sixth aspect of the present invention is the metal detection device according to the fifth aspect of the present invention, wherein the appropriate interval stored in the storage unit is the length of the receiving coil in the article conveyance direction.

  Here, the appropriate interval is determined based on the length of the receiving coil of the metal detection unit in the conveyance direction of the article.

  Thus, it is possible to inspect the next conveyed article while ensuring the time until the noise of the detection signal disappears after the detection of the substance having a metal property in the receiving coil and returns to the initial state. it can.

  A metal detection device according to a seventh aspect of the invention is the metal detection device according to any one of the first to sixth aspects of the invention, wherein an appropriate interval is detected after a substance having a metal property is detected in the metal detection unit. This is determined based on the time required for the receiving coil to return to the initial state.

  Here, the appropriate interval between articles is determined so that the next article is inspected after the receiving coil of the metal detector returns to the initial state.

  This prevents the next article from being conveyed while the noise of the detection signal remains after detecting a substance having a metal property in the receiving coil, and after the receiving coil returns to the initial state. The next item can be inspected. Therefore, it is possible to ensure an appropriate interval at which a highly accurate inspection can always be performed.

  A metal detection device according to an eighth invention is the metal detection device according to any one of the first to seventh inventions, wherein the interval detection unit includes a photoelectric sensor that detects passage of an article, and a photoelectric sensor. And a timer for measuring a time after the article is detected.

  Here, by measuring the time after the article is detected by the photoelectric sensor that detects the passage of the article with a timer, it is detected whether or not the article is being conveyed at an appropriate interval.

  Thereby, the length of the proper interval can be managed by the parameter of time. It is assumed that the time managed in this timer changes according to the transport speed in the transport unit.

  A metal detection device according to a ninth invention is the metal detection device according to any one of the first to eighth inventions, and distributes articles whose determination is invalidated by the control unit from the conveyance path in the conveyance unit. A distribution unit is further provided.

  Here, a distribution unit is further provided that distributes articles determined to be defective in the determination unit and articles determined to be invalid in the control unit in a predetermined direction from the conveyance path.

  Thereby, the articles determined to be defective can be discarded, and the articles whose determination is invalid can be re-inspected with a proper interval. The distribution unit is configured not only to distribute normal articles and other articles, but also to distribute other articles to articles that are determined to be defective and articles that are determined to be invalid. It may be.

  According to the metal detection device of the present invention, it is possible to prevent articles conveyed close to each other from flowing to the downstream side while being erroneously determined. By performing the re-inspection, the accuracy of the inspection can be improved.

  A metal detection apparatus according to an embodiment of the present invention will be described below with reference to FIGS.

[Configuration of Metal Detector 10]
As shown in FIG. 1, the metal detection apparatus 10 according to the present embodiment is mixed with a substance having a metal property such as metal or oxygen scavenger while continuously conveying a plurality of inspection objects (articles) P. It is an inspection device that inspects whether or not it is. Further, the metal detection device 10 includes a transfer conveyor (transfer unit) 11, a metal detection unit 12, a setting input unit 15, a photoelectric sensor (interval detection unit) 16 (see FIG. 2), a distribution unit 18, and a control unit (determination unit). , Control unit) 40 (see FIG. 3).

  The conveyor 11 continuously conveys the inspection object P placed on the belt in a predetermined direction while rotating the endless belt by the driving roller.

  The metal detection unit 12 is an apparatus for detecting the oxygen scavenger M contained in the inspection object P conveyed by the conveyor 11 and includes an upper head 21 and a lower head 22.

  The upper head 21 is arranged so as to sandwich the central portion of the conveyor 11 together with the lower head 22. As shown in FIG. 4, the upper head 21 includes a transmission coil 21a constituting the metal detector 12, and an alternating magnetic field is applied to a region including the lower head 22 (reception coil 22a) by the transmission coil 21a. generate.

  As shown in FIG. 4, the lower head 22 includes two receiving coils 22 a and 22 b in an area of an alternating magnetic field formed by the transmitting coil 21 a of the upper head 21. Then, by calculating the difference between the detection signals in the two receiving coils 22a and 22b, it is detected whether or not the oxygen scavenger M has passed over the conveyor 11 included in the alternating magnetic field.

  In the metal detection device 10 of the present embodiment, when the inspection object P including the oxygen scavenger M having a metal property passes through the alternating magnetic field formed by the transmission coil 21a of the upper head 21, the reception of the lower head 22 is performed. The waveform of the metal detection signal indicating the current flowing through the coils 22a and 22b changes. For this reason, by taking the difference between the detection signal waveforms in the receiving coils 22a and 22b when a substance having a metallic property passes through the alternating magnetic field, the oxygen is removed in the inspection object P transported by the transport conveyor 11. Whether or not the agent M is contained can be easily determined.

  The setting input unit 15 performs various settings such as a conveyance speed of the conveyor 11, an appropriate interval between inspection objects P described later, and a time limit setting by a timer 17.

  As shown in FIG. 2, the photoelectric sensor 16 is arranged on the upstream side of the metal detection unit 12 and on the side of the conveyor 11 and includes a light emitting element 16 a and a light receiving element 16 b. The light emitting element 16 a irradiates light parallel to the transport path in a direction perpendicular to the transport direction of the transport conveyor 11 at a position lower than the inspection object P. The light receiving element 16b receives the light emitted from the light emitting element 16a. That is, the time during which the light irradiated from the light emitting element 16a in the photoelectric sensor 16 is not blocked by the inspection object P is measured, and the interval between the inspection objects P is determined based on the conveyance speed in the conveyance conveyor 11 and the measurement time. The interval X can be measured. In addition, the photoelectric sensor 16 has a detection region of the metal detection unit 12 whose rear end passes through the front of the photoelectric sensor 16 in the conveyance direction in the inspection object P managed by the timer 17 described later. The start timing for measuring the time until passing through is determined.

  The timer 17 manages the time from when the inspection object P transported by the transport conveyor 11 is detected by the photoelectric sensor 16 until it passes through the detection region by the metal detection unit 12. Specifically, the inspection object P is in an alternating magnetic field formed by the metal detection unit 12 (transmission coil 21a) after the photoelectric sensor 16 (light receiving element 16b) starts to be shielded from light by the inspection object P conveyed first. The time taken to pass through is managed for each inspection object P. When the photoelectric sensor 16 is shielded from light by the next inspection object P before the timer 17 expires, the control unit 40 invalidates the determination of the rear inspection object P.

  The distribution unit 18 is disposed on the downstream side of the metal detection unit 12 in the conveyor 11. Then, the inspection object P that is invalidated by the control unit 40 and the inspection object P detected as a defective product in which the oxygen scavenger M is not mixed are shaken off from the conveyance path as shown in FIG. Rotate for.

  Next, a control unit 40 that reads various programs stored in a RAM (storage unit) 35 and the like provided in the metal detection device 10 of the present embodiment and executes operation control of each unit will be described with reference to FIG. If it is as follows.

  As shown in FIG. 3, the control unit 40 includes a bus line 30, a CPU 31, a clock oscillation circuit 32, an I / O interface 33, a ROM 34, a RAM 35, a detection / filter circuit 36, an oscillation circuit 37, and an A / D conversion circuit 38. It has.

  The metal detection unit 12 (transmission coil 21 a and reception coils 22 a and 22 b) is connected to an oscillation / filter circuit 36 and an oscillation circuit 37 included in the control unit 40. The detection / filter circuit 36 is connected to the bus line 30 via the A / D conversion circuit 38. For this reason, the metal detection signals from the receiving coils 22 a and 22 b are subjected to various processes, are A / D converted, and are supplied to each unit via the bus line 30.

  The bus line 30 is connected to a CPU 31, a ROM 34, and a RAM 35 to which a clock oscillation circuit 32 is connected. The bus line 30 is further connected to the transport conveyor 11, the setting input unit 15, the photoelectric sensor 16, the timer 17, and the distribution unit 18 via the I / O interface 33.

  In the RAM 35, good determination is made when the speed data (transport speed data) of the transport conveyor 11, the length in the transport direction of the inspection object (product) P, and a plurality of inspection objects P are transported continuously. Data such as an appropriate interval between inspection objects P (hereinafter simply referred to as “appropriate interval”) and various programs for controlling the operation of each part are stored. In addition, the data of the appropriate interval stored in the RAM 35 are data set based on the length Y (see FIG. 4) in the transport direction of the receiving coils 22a and 22b of the metal detector 12, and the data Data including a margin for ensuring a time for the metal reaction in the detection unit 12 to disappear and return to the initial state can be used.

  In the metal detection device 10 of the present embodiment, the control unit 40 having the above-described configuration causes the control unit 40 to read the determination program out of various programs stored in the RAM 35 and execute it. It functions as a determination unit that determines the presence or absence of the oxygen scavenger M contained in the test object P. Further, whether or not the control unit 40 invalidates the determination regarding the inspection object P conveyed at an interval narrower than the appropriate interval by the CPU 31 reading and executing the appropriate interval determining program stored in the RAM 35. It functions as a controller for determining.

[Inspection Method in Metal Detector 10]
In the metal detection device 10 of the present embodiment, the inspection for confirming that the oxygen scavenger M is included in each inspection object P will be described below with reference to the flowcharts shown in FIGS. 5 and 7. It is as follows.

  First, as shown in FIG. 6, the oxygen scavenger M is mixed on the inspection object P side that is transported first among the plurality of inspection objects P that are transported continuously, and is transported later. A case where the oxygen absorber M is not mixed in the inspection object P will be described. In this case, when the distance X between the previous inspection object P and the rear inspection object P is equal to or less than the appropriate distance stored in the RAM 35, the oxygen scavenger M contained in the previous inspection object P is detected. Under the influence of the noise remaining in the receiving coils 22a and 22b for a predetermined time, there is a possibility that the oxygen to be detected is erroneously detected in the object P to be inspected later. And when such a misjudgment arises, it will be conveyed as it is, without being distributed as a normal article about the to-be-inspected object P in which the oxygen absorber M is not mixed.

  In the metal detection device 10 according to the present embodiment, in consideration of the fact that the plurality of objects to be inspected P are transported close to each other so that the determination of metal contamination cannot be performed accurately, a predetermined appropriate interval or less. With respect to the inspection object P transported in the above, the determination result of the rear object P is invalidated.

  Specifically, as shown in FIG. 5, in step S <b> 1, it is determined based on detection signals in the receiving coils 22 a and 22 b of the metal detector 12 whether or not the oxygen scavenger M is mixed in the inspection object P. To do. Here, when the oxygen scavenger M is not mixed, the process proceeds to step S4, and as shown in FIG. 9, the sorting unit 18 determines a defective product from the transport conveyor 11 in a predetermined direction (two points in FIG. 9). (See the dashed arrows).

  On the other hand, when it is determined in step S1 that the oxygen scavenger M is mixed in the inspection object P, the process proceeds to step S2 where the distance from the previous inspection object P is an appropriate interval stored in the RAM 35. It is determined whether or not: Here, if it is equal to or less than the appropriate interval, the process proceeds to step S5, the determination in step S1 is invalidated, and in step S6, the redistribution product is distributed from the transport path by the distribution unit 18 (see FIG. 9).

  If it is determined in step S2 that the sheet is transported at a sufficient interval and not at an appropriate interval, the process proceeds to step S3 and is transported downstream as a normal product without being sorted by the sorting unit 18. Is done.

  Next, as shown in FIG. 8, the oxygen scavenger M is not mixed in the inspection object P that is transported first among the plurality of inspection objects P that are continuously transported. A case where the oxygen absorber M is mixed in the inspection object P to be inspected will be described. In this case, when the distance X between the front inspection object P and the rear inspection object P is equal to or less than the appropriate distance stored in the RAM 35, the previous inspection object P passes through the detection region in the metal detection unit 12. The oxygen scavenger M detected by detecting the oxygen scavenger M contained in the back inspection object P before the inspection is included in the object under inspection P or included in the object under inspection P. You will not know if you are. And when such a misjudgment arises, it will be conveyed as it is, without being distributed by the distribution part 18 as a normal article about the to-be-inspected object P in which the oxygen absorber M is not mixed.

  In the present embodiment, in consideration of the fact that determination of metal contamination cannot be made accurately because a plurality of inspection objects P are transported close to each other in this way, the object to be transported at a predetermined appropriate interval or less. For the inspection object P, the determination result of the previous object P is invalidated.

  Specifically, as shown in FIG. 7, in step S <b> 11, it is determined based on detection signals in the receiving coils 22 a and 22 b of the metal detection unit 12 whether or not the oxygen scavenger M is mixed in the inspection object P. To do. Here, if the oxygen scavenger M is not mixed, the process proceeds to step S14, and as shown in FIG. 9, the sorting unit 18 determines a defective product from the transport conveyor 11 in a predetermined direction (two points in FIG. 9). (See the dashed arrows).

  On the other hand, if it is determined in step S11 that the oxygen scavenger M is mixed in the inspection object P, the process proceeds to step S12, and the interval between the inspection object P and the rear inspection object P is an appropriate interval stored in the RAM 35. It is determined whether or not: Here, if it is equal to or less than the appropriate interval, the process proceeds to step S15 to invalidate the determination in step S11, and in step S16, the redistribution product is distributed from the conveyance path by the distribution unit 18 (see FIG. 9).

  If it is determined in step S12 that the sheet is transported at a sufficient interval and not at an appropriate interval, the process proceeds to step S13, and is transported downstream as a normal product without being sorted by the sorting unit 18. Is done.

  In the case shown in FIG. 8, not only the inspection object P transported earlier but also the inspection result of the rear inspection object P may be erroneous, so that both are spaced at an appropriate interval. More preferably, a retest is performed above.

[Features of the metal detection apparatus 10]
(1)
In the metal detection device 10 of the present embodiment, when the control unit 40 detects the detection result in the metal detection unit 12, the interval between the objects P measured by the photoelectric sensor 16 is equal to or less than the appropriate interval stored in the RAM 35. The control for invalidating the detection result is performed.

  Thereby, about the to-be-inspected object P conveyed adjacently, the other to-be-inspected object P was not correctly test | inspected by the influence which detected the deoxidation agent M contained in one to-be-inspected object P. Even in this case, it is possible to prevent the sheet from being conveyed while being erroneously detected. Therefore, the inspection accuracy can be improved by carrying out a re-inspection at an appropriate interval with respect to the inspection object P which is transported close to each other and there is a possibility that an accurate inspection result cannot be obtained. .

(2)
In the metal detection device 10 of the present embodiment, the control unit 40 determines that the inspection object P mixed with the oxygen scavenger M is a non-defective product. That is, the objects to be weighed P that do not contain the oxygen scavenger M are distributed as defective products.

  On the other hand, in a metal detection apparatus that determines that an object to be inspected that does not contain the oxygen scavenger M is a non-defective product and that the object to be inspected is a defective product, both of the objects to be inspected that are transported close to each other are not acceptable. It is not a big problem because it is judged as a non-defective product and distributed.

  On the other hand, as in the present embodiment, in the metal detection device 10 that sorts the inspection object P that does not contain the oxygen scavenger M as a defective product, the inspection object P that is transported close to each other is determined as a non-defective product. Therefore, there is a possibility that the erroneously detected inspection object P is conveyed as it is as a non-defective product.

  However, in the metal detection apparatus 10 of the present embodiment, the inspection object P to be transported close to each other is invalidated as one or both of the determination results, so that it is transported as a non-defective product as it is. Can be prevented.

(3)
In the metal detection device 10 of the present embodiment, as shown in FIG. 6, the oxygen scavenger M is mixed into the inspection object P that is transported first among the plurality of inspection objects P that are continuously transported. In the case where the oxygen scavenger M is not mixed in the object P to be transported later, and the objects P that are transported closer to each other than the proper interval, The determination on the object P is invalidated.

  Thereby, even if the determination of the rear inspection object P is wrong due to the detection of the oxygen scavenger M mixed in the previous inspection object P, the rear inspection object P is appropriate. Can be sent to a re-examination at intervals. As a result, the accuracy of inspection can be improved.

(4)
In the metal detection device 10 of the present embodiment, as shown in FIG. 8, the oxygen scavenger M is mixed into the inspection object P that is conveyed behind among the plurality of inspection objects P that are continuously conveyed. In the case where the oxygen scavenger M is not mixed in the object P to be transported first, and the objects P that are transported closer to each other than the appropriate distance, The determination on the object P is invalidated.

  Thereby, due to the influence of detecting the oxygen scavenger M mixed in the back inspection object P before the inspection object P transported first is not yet completely out of the detection region of the metal detection unit 12, Even if the determination of the previous inspection object P is incorrect, the previous inspection object P can be sent to a re-inspection with an appropriate interval. As a result, the accuracy of inspection can be improved.

(5)
In the metal detection device 10 of this embodiment, as shown in FIG. 4, the metal detection unit 12 includes a transmission coil 21 a in the upper head 21 and reception coils 22 a and 22 b in the lower head 22.

  As a result, when a substance such as oxygen scavenger M having metallic properties passes through an alternating magnetic field formed by the transmission coil 21a, a change in the waveform of the metal detection signal appearing in the reception coils 22a and 22b is observed. By doing so, it can be easily inspected whether or not a substance having a metal property is contained.

(6)
In the metal detector 10 of this embodiment, the length Y in the conveyance direction of the receiving coils 22a and 22b is used as a reference for setting an appropriate interval stored in the RAM 35 (see FIG. 4).

  As a result, the inspection object P transported first and the inspection object P behind enter at the same time immediately above the reception coils 22a and 22b (detection region) where the alternating magnetic field is formed by the transmission coil 21a. Can be prevented. As a result, it is possible to prevent the other inspection object P from being erroneously detected due to the influence of detecting the oxygen scavenger M contained in the one inspection object P.

(7)
In the metal detection device 10 of the present embodiment, the reception coils 22a and 22b detect the oxygen scavenger M in addition to the length Y in the conveyance direction of the reception coils 22a and 22b described above for the appropriate interval stored in the RAM 35. After that, an appropriate interval is set in consideration of a margin time until the initial state is restored.

  Thereby, even when the to-be-measured object P before and behind conveyed close to each other does not enter into the detection region immediately above the receiving coils 22a and 22b, the receiving coils 22a and 22b detect the oxygen scavenger M. In consideration of the margin time from the start to the return to the initial state, the appropriate interval can be further widened. As a result, the inspection accuracy can be improved more reliably.

(8)
In the metal detection device 10 of the present embodiment, the timer 17 manages the time after the photoelectric sensor 16 detects the front end of the inspection object P in the transport direction.

  As a result, when the next inspection object P passes before the time required for opening an appropriate interval that changes according to the conveyance speed of the conveyance conveyor 11 has passed, the control unit 40 causes the object to be detected before and after the inspection object P to pass. The determination of one or both of the weighing objects P can be invalidated.

(9)
In the metal detection device 10 of the present embodiment, a distribution unit that distributes the inspection object P determined to be invalid by the control unit 40 or the inspection object P determined to be defective from the conveyance conveyor 11 to the outside of the conveyance path. 18 is further provided.

  As a result, the inspection object P that needs to be reinspected or the inspection object P to be discarded as a defective product can be prevented from being transported downstream as it is, and only good products can be transported downstream. it can.

[Other Embodiments]
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the summary of invention.

(A)
In the said embodiment, the metal detection apparatus 10 which performs the test | inspection for confirming that the oxygen scavenger M was mixed was mentioned as an example, and was demonstrated. However, the present invention is not limited to this.

  For example, on the contrary, the present invention may be applied to a metal detection device that performs an inspection for confirming that a metal piece or the like is not mixed in a product. In this case as well, the inspection accuracy can be improved by invalidating the determination of one or both of the objects to be inspected and transported in close proximity to each other and performing a re-inspection. The effect of can be obtained.

  However, in the inspection to confirm that the substance having the metal property is not mixed, the articles conveyed in close proximity to each other are discharged as defective products mixed with the substance having the metal property. It doesn't matter. On the other hand, as in the above embodiment, applying the present invention to the metal detection device 10 that performs an inspection for confirming that the oxygen scavenger M is mixed is that a substance having a metal property is used. It is more preferable in that the problem of being erroneously determined as a good product even though it is not mixed can be solved.

(B)
In the said embodiment, the metal detection apparatus 10 which performs the test | inspection regarding the presence or absence of mixing of the oxygen absorber M which has the property of the metal contained in the to-be-inspected object P was mentioned as an example, and was demonstrated. However, the present invention is not limited to the oxygen scavenger M as an object to be inspected.

  For example, it may be a metal detection device that performs an inspection regarding the presence or absence of silica gel as a substance having metal properties other than the oxygen scavenger. Furthermore, the metal detection apparatus which performs the test | inspection regarding mixing with goods, such as a metal piece, as a substance which has a metal property may be sufficient. Also, a plastic bag with oxygen scavenger, a soup (eg instant noodle soup sachet) in a bag made of aluminum foil or aluminum deposited film, and a small box with metal bonus It may be a metal detection device that performs an inspection for confirming that etc. are contained.

(C)
In the above-described embodiment, an example in which an appropriate distance is set based on the distance X between the rear end of the inspection object P conveyed first and the front end of the inspection object P conveyed rearward has been described. However, the present invention is not limited to this.

  For example, instead of the distance between the rear end and the front end of the inspection object P, the product pitch (the distance between the front end of the inspection object P conveyed first and the front end of the inspection object P conveyed rearward). ) May be used as a reference to measure the appropriate distance. The appropriate distance in this case may be, for example, (length in the transport direction of the inspection object P) + (length in the transport direction of the receiving coil).

(D)
In the said embodiment, the example which detects the passage of the to-be-inspected object P by the presence or absence of light shielding in the photoelectric sensor 16 was given and demonstrated. However, the present invention is not limited to this.

  For example, in addition to the photoelectric sensor, other detection means such as an infrared sensor can be used.

(E)
In the above embodiment, the metal detection apparatus 10 that shakes off the inspection object P whose determination is invalidated by the distribution unit 18 or the defective inspection object P in which the oxygen scavenger M is not mixed is taken as an example. As explained above. However, the present invention is not limited to this.

  For example, the sorting unit 18 is provided in a plurality of stages, and the inspection object P in which the determination is invalidated due to the proximity conveyance of an appropriate interval or less and the inspection of a defective product in which the oxygen scavenger M is not mixed. The structure which distributes the thing P separately may be sufficient. In this case, since only the inspection object P that needs to be reinspected can be selected from the defective inspection object P, reinspection can be performed smoothly.

(F)
In the said embodiment, the metal detection part 12 with which the metal detection apparatus 10 is equipped is arrange | positioned in the transmission coil 21a which generates an alternating magnetic field, and the alternating magnetic field, and the substance (deoxygenating agent) which has the property of a metal is An example in which the receiving coils 22a and 22b that detect passing is provided has been described. However, the present invention is not limited to this.

  For example, it is possible to employ a detection unit other than the configuration using the transmission / reception coil as the metal detection unit.

  The metal detection device of the present invention makes it possible to invalidate an article that has been erroneously determined by invalidating the determination of the article when the interval between the articles is equal to or less than the appropriate interval for a plurality of articles that are continuously conveyed. Since it has an effect that it can be prevented from flowing downstream without being detected, it can be widely applied to various inspection apparatuses that inspect while continuously conveying a plurality of articles.

The perspective view which shows the schematic structure of the metal detection apparatus which concerns on one Embodiment of this invention. The top view which shows the metal detection apparatus of FIG. The control block diagram which the metal detection apparatus of FIG. 1 has. The front view which shows the metal detection apparatus of FIG. The flowchart which shows the flow of the test | inspection by the metal detection apparatus of FIG. The top view which shows the test | inspection Example in the metal detection apparatus of FIG. The flowchart which shows the flow of the test | inspection by the metal detection apparatus of FIG. The top view which shows the test | inspection Example in the metal detection apparatus of FIG. The top view which shows the operation | movement at the time of performing the distribution of the inferior goods in the metal detection apparatus of FIG.

Explanation of symbols

10 Metal detector 11 Conveyor (conveyance unit)
12 metal detection unit 15 setting input unit 16 photoelectric sensor 16a light emitting element 16b light receiving element 17 timer 18 distribution unit 21 upper head 21a transmission coil 22 lower head 22a reception coil 22b reception coil 30 bus line 31 CPU
32 Clock oscillation circuit 33 I / O interface 34 ROM (storage unit)
35 RAM (storage unit)
36 Detection / filter circuit 37 Oscillation circuit 38 A / D conversion circuit M Oxygen scavenger (metal or material having metal properties)
P Inspection object (article)
S step

Claims (9)

A transport unit for continuously transporting a plurality of articles to be inspected;
A metal detection unit for detecting a metal or a substance having a metal property contained in the article conveyed by the conveyance unit;
A determination unit for determining whether or not the article contains a metal or a substance having a property of metal based on a detection result in the metal detection unit;
A storage unit for storing an appropriate interval of each article conveyed in the conveyance unit;
An interval detection unit that detects an interval of each article conveyed in the conveyance unit;
When the detection result in the interval detection unit is equal to or less than the appropriate interval stored in the storage unit, a control unit invalidating the determination result in the determination unit;
A metal detection device. The determination unit determines that the article is a non-defective product when a metal or a substance having a metal property is included.
The metal detection device according to claim 1. When the control unit detects a metal or a substance having a metal property with respect to the article that has been conveyed earlier among the articles that have been conveyed within the appropriate interval or less, a determination result of the subsequent article is displayed. Invalidate,
The metal detection device according to claim 1 or 2. When the control unit detects a metal or a substance having a metal property in the rear article among the articles conveyed within the appropriate interval, the determination result of the article conveyed first Disable
The metal detection device according to claim 1 or 2. The metal detection unit includes a transmission coil that generates an alternating magnetic field and a reception coil that is disposed in the alternating magnetic field.
The metal detection apparatus of any one of Claim 1 to 4. The appropriate interval stored in the storage unit is the length of the receiving coil in the conveyance direction of the article.
The metal detection device according to claim 5. The appropriate interval is determined based on a time required for the receiving coil to return to an initial state after detecting a metal or a substance having a metal property in the metal detector.
The metal detection apparatus of any one of Claim 1 to 6. The interval detector includes a photoelectric sensor that detects passage of the article, a timer that measures time after the article is detected by the photoelectric sensor,
With
The metal detection apparatus of any one of Claim 1 to 7. A distribution unit that distributes the article whose determination is invalidated in the control unit from a conveyance path in the conveyance unit;
The metal detection apparatus of any one of Claim 1 to 8.

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