Optical sorting machine

Abstract

To improve control related to involvement removal in a multistage optical sorter.SOLUTION: An optical sorter includes: a light source configured to apply light to a target object for sorting being transferred; an optical sensor configured to detect light applied from the light source and associated with the target object; and a sorter which has a nozzle for injecting fluid and is configured to sort a target object by injecting fluid from the nozzle to a specific target object which is determined based on a signal acquired by the optical sensor. The optical sorter has N-th order sorting systems (N is an integer of 2 or greater) each configured to perform optical sorting with the light source, the optical sensor and the sorter. At least two sorting systems of the N-th order sorting systems are operably configured to be different from each other in settings that affect an injection range of fluid to the specific sorting object by the sorter.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a sorting technique in an optical sorting machine. [Background technology]

[0002] Optical sorting machines (hereinafter simply referred to as sorters) have been known for some time. These machines use optical information obtained by an optical sensor when light is irradiated onto the objects to be sorted from a light source to identify and remove defective items from the objects. In these types of sorting machines, the optical information (e.g., color gradation values) obtained by the optical sensor is compared with a threshold value, and based on the comparison results, the objects are determined to be good or defective. Air is then sprayed onto either the objects determined to be good or defective. This separates the objects into good and defective.

[0003] Such a sorting machine may be configured to be capable of performing multi-stage sorting (hereinafter also referred to as a multi-stage sorting machine). For example, Patent Document 1 listed below discloses a sorting machine capable of performing two-stage sorting. Specifically, in a primary sorting system, air is sprayed onto objects to be sorted that have been determined to be defective, and objects discharged from the primary sorting system as non-defective are collected as non-defective, and objects discharged from the primary sorting system as defective are input into a secondary sorting system. In the secondary sorting system, air is sprayed onto objects to be sorted that have been determined to be defective, and objects discharged from the secondary sorting system as non-defective are collected as non-defective, and objects discharged from the secondary sorting system as defective are collected as defective.

[0004] With this sorting machine, even if objects to be collected as non-defective products are mixed in with defective products due to collateral removal in the primary sorting system, the non-defective products can ultimately be collected as non-defective products by re-sorting in the secondary sorting system. Therefore, compared to a sorting machine with only a single sorting system, the yield can be improved without reducing the purity of non-defective products. Note that collateral removal refers to the removal of objects adjacent to the objects to be removed when air is sprayed onto the objects to be removed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 60-241979 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the technology of Patent Document 1, non-defective products that are removed together with defective products in the secondary sorting system are collected as defective products. Therefore, further improvement in the control of the removal of non-defective products is still required. [Means for solving the problem]

[0007] The present invention has been made to solve at least part of the above-mentioned problems, and can be realized, for example, in the following forms.

[0008] According to a first aspect of the present invention, there is provided an optical sorting machine. The optical sorting machine includes a light source configured to irradiate light onto objects being transported, an optical sensor configured to detect light irradiated from the light source and associated with the objects, and a sorting device having a nozzle for spraying a fluid and configured to spray air from the fluid toward specific objects to be sorted, which are determined based on a signal acquired by the optical sensor, to sort the objects. The optical sorting machine includes N-th (N is an integer of 2 or greater) sorting systems, each configured to perform optical sorting using the light source, the optical sensor, and the sorting device. At least two of the N-th sorting systems are configured to be operable so that settings affecting the spray range of the fluid toward specific objects by the sorting device are different from each other.

[0009] "Light associated with the objects to be sorted" may be reflected light that is light reflected by the objects to be sorted, transmitted light that is light that is transmitted through the objects to be sorted, or both reflected light and transmitted light. Alternatively, instead of or in addition to reflected light and / or transmitted light, "light associated with the objects to be sorted" may include light that is generated by fluorescence when light is irradiated onto objects to be sorted that contain a fluorescent substance.

[0010] The "spray range" of a fluid for a specific object to be sorted is not limited to the range into which the fluid is sprayed at a given moment, but refers to the range in a coordinate system that moves along with the object being transported. For example, the relative positional relationship between the object being transported and the area into which the fluid is sprayed changes from moment to moment as the object is transported, but the entire coordinate area in which the fluid hits, even for just an instant, in the coordinate system that moves along with the object can be the "spray range" of the fluid for the object to be sorted.

[0011] This optical sorter can operate with different settings affecting the fluid injection range between at least two of the N-th sorting system. Because the wider the fluid injection range, the greater the probability of collateral removal. This operation means that the probability of collateral removal in the flow of sorted objects through each sorting system can be appropriately controlled for each sorting system. Therefore, it is easier to achieve the desired sorting accuracy and yield. For example, when sorting objects into non-defective and defective, setting the fluid injection range for the sorting system that has the final step of spraying fluid on defective objects in the flow of sorted objects through each sorting system relatively narrow prevents non-defective objects from being collaterally removed along with defective objects in that sorting system. In other words, this prevents non-defective objects from being mixed in with the objects ultimately collected as defective. Therefore, compared to conventional optical sorters in which the settings affecting the fluid injection range are the same for each sorting system, the optical sorter as a whole can further reduce the amount of non-defective objects being collaterally removed, thereby improving yield.

[0012] According to a second aspect of the present invention, in the first aspect, the settings that affect the fluid injection range include setting the fluid injection pressure. The higher the fluid injection pressure, the wider the area of ​​the injected fluid spreads. In other words, the higher the fluid injection pressure, the wider the area of ​​influence of the fluid (the area over which the force of the injected fluid can act on the objects to the extent that the trajectory of the objects can be changed). Therefore, according to this aspect, the fluid injection range can be easily controlled.

[0013] According to a third aspect of the present invention, in the second aspect, the sorting device is provided with a pressure regulating valve configured to regulate the pressure of the fluid supplied to the nozzle for each of the Nth sorting systems. According to this aspect, since a pressure regulating valve is provided individually for each of the Nth sorting systems, the injection pressure of the fluid for each of the Nth sorting systems can be easily controlled to a desired value.

[0014] According to a fourth aspect of the present invention, in any one of the first to third aspects, the settings that affect the fluid spray range include setting the fluid spray duration. The longer the fluid spray duration, the wider the fluid spray range in the coordinate system that moves with the objects being transported becomes in the direction of transport of the objects. Therefore, according to this aspect, the fluid spray range can be easily controlled.

[0015] According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the nozzle includes a plurality of openings capable of selectively ejecting fluid. The plurality of openings are arranged in an intersecting direction, which is a direction intersecting the transport direction of the objects. Each of the plurality of openings is associated with a corresponding ejection range for each detection position of the objects in the intersecting direction. The setting that affects the fluid ejection range includes setting the ejection range. Such an ejection range may be set, for example, so that adjacent openings in one of at least two sorting systems overlap, and so that adjacent openings in the other system do not overlap. With this setting, when a specific object is detected in an overlapping ejection range, a larger number of openings will eject fluid toward the specific object compared to when the specific object is detected in a non-overlapping ejection range. This means that the fluid ejection range is expanded in the intersecting direction. Alternatively, the spray coverage area may be set so that adjacent openings overlap in one of the at least two sorting systems, and so that adjacent openings overlap to a smaller extent in the other sorting system. According to these exemplary settings, the probability (frequency) of an event in which fluid is sprayed from a larger number of openings (in other words, an event in which the fluid spray coverage area is expanded) differs between the at least two sorting systems. Expanding the fluid spray coverage area means that the probability of collateral removal increases. Therefore, this embodiment also makes it possible to control the probability of collateral removal.

[0016] According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the optical sorter includes a controller configured to be able to change settings that affect the fluid spray range. According to this aspect, a user can change the settings that affect the fluid spray range according to the properties (e.g., specific gravity) of the objects to be sorted, or according to the required sorting accuracy and / or yield. This improves user convenience and the versatility of the optical sorter.

[0017] According to a seventh aspect of the present invention, in any one of the first to sixth aspects, the settings that affect the fluid ejection range include the nozzle structure. According to this aspect, the fluid ejection range can be easily controlled.

[0018] According to an eighth aspect of the present invention, in any one of the first to seventh aspects, the optical sorting machine includes at least a primary sorting system and a secondary sorting system as an N-th sorting system. The optical sorting machine is configured to sort the objects into first-quality objects having a first quality and second-quality objects having a second quality different from the first quality. The optical sorting machine is further configured to spray a fluid onto the objects determined to be second-quality objects based on the signal in the primary sorting system, thereby sorting the objects into a first group of objects that have not been sprayed with the fluid and a second group of objects that have been sprayed with the fluid, and to discharge the first group of objects from the primary sorting system as first-quality objects and input the second group of objects to the secondary sorting system. The optical sorting machine is further configured to spray the fluid onto the objects determined to be of second quality based on the signal in the secondary sorting system, thereby separating the second group of objects into a third group of objects that have not been sprayed with the fluid and a fourth group of objects that have been sprayed with the fluid, and to re-introduce the third group of objects into the primary sorting system. The settings affecting the fluid spray range in the primary sorting system are configured so that the fluid spray range is wider than the fluid spray range in the secondary sorting system, or the frequency with which the range becomes wider increases. This configuration makes it possible to easily achieve both desired sorting accuracy and yield. Here, "quality" may refer to the degree of superiority or inferiority of desirable (or undesirable) properties of each object. Such "quality" may include the severity of the defect and the size of the defective portion. The second quality may be inferior to the first quality. For example, if the first quality product is a good product and the second quality product is a defective product, the range of fluid sprayed on the defective product in the primary sorting system is relatively wide, or the frequency with which it becomes wide is relatively high, so the defective product can be reliably removed and the purity of the good products discharged from the primary sorting system is high.Furthermore, since the third group of sorted objects (in other words, objects discharged as non-defective from the secondary sorting system) is re-introduced into the primary sorting system, even if objects to be recovered as non-defective are mixed into the second group of sorted objects (in other words, objects discharged as defective from the primary sorting system) due to collateral removal in the primary sorting system, the non-defective objects removed as collateral can ultimately be recovered as non-defective by re-sorting in the secondary sorting system. This improves the yield of the optical sorting machine as a whole. Moreover, in the secondary sorting system, the fluid spray range for defective objects is relatively narrow or the frequency with which it widens is relatively low, preventing non-defective objects from being caught up in and removed along with the defective objects. This increases the amount of non-defective objects contained in the third group of sorted objects re-introduced into the primary sorting system, further improving the yield. Furthermore, although the reliability of removing defective products in the secondary sorting system is lower than in the primary sorting system (the probability of defective products being mixed into the third group of sorted objects is higher), the third group of sorted objects is re-introduced into the primary sorting system, which can recover high-purity non-defective products, so the optical sorting machine as a whole can ensure a good purity of non-defective products. Therefore, it is possible to achieve both an improvement in the purity of non-defective products and an improvement in yield.

[0019] According to a ninth aspect of the present invention, in the eighth aspect, the optical sorter further includes a tertiary sorting system as an N-th sorting system. The optical sorter is configured so that a fourth group of objects to be sorted is input into the tertiary sorting system. The optical sorter is further configured so that, in the tertiary sorting system, a fluid is sprayed onto objects determined to be first-quality objects based on a signal, so that the fourth group of objects to be sorted is sorted into a fifth group of objects to which the fluid is not sprayed and a sixth group of objects to which the fluid is sprayed, the fifth group of objects to be sorted is discharged from the tertiary sorting system as second-quality objects, and the sixth group of objects to be sorted is re-input into the second sorting system. Settings that influence the fluid spray range in the first sorting system are configured so that the fluid spray range in the first sorting system is wider than the fluid spray ranges in the second and tertiary sorting systems, or so that the wider range becomes more frequently. According to this embodiment, it is possible to achieve both improved sorting accuracy and improved yield at an even higher level. Specifically, for example, if the second quality is inferior to the first quality, the first-quality items are good products, and the second-quality items are defective products, the sixth group of sorted items (in other words, the sorted items discharged as good products from the tertiary sorting system) is re-introduced into the second sorting system and ultimately recovered as good products from the primary sorting system, thereby further improving yield. Furthermore, in the tertiary sorting system, the fluid spray range on the defective products is relatively narrow or the frequency with which it widens is relatively low, thereby preventing the defective products from being removed together with the good products. This allows the purity of the good products to be increased. Moreover, it is possible to prevent the defective products from being removed together with the good products and re-introduced into the second sorting system, thereby preventing a loop between the second and third sorting systems.

[0020] According to a tenth aspect of the present invention, in the eighth aspect, the optical sorting machine is configured so that the fourth group of objects to be sorted is discharged as second-quality objects from the secondary sorting line. This aspect can obtain the same effect as the eighth aspect with a simple configuration. [Brief explanation of the drawings]

[0021] [Figure 1]FIG. 2 is a block diagram showing an example of the flow of objects to be sorted in the optical sorting machine according to the first embodiment when the rate of defective items mixed in is low. [Figure 2] FIG. 2 is a schematic diagram showing the general configuration of the primary to tertiary sorting systems. [Figure 3] 1 is a schematic diagram showing the positional relationship of the chute, light source, optical sensor, and nozzle in a direction intersecting the rice transport direction. FIG. [Figure 4] FIG. 1 is a block diagram showing an example of a schematic configuration of a sorting device. [Figure 5] FIG. 2 is a block diagram showing an example of the flow of objects to be sorted in the optical sorting machine according to the first embodiment when the rate of defective products mixed in is medium. [Figure 6] FIG. 2 is a block diagram showing an example of the flow of objects to be sorted in the optical sorting machine according to the first embodiment when the rate of defective items mixed in is high. [Figure 7] 10A and 10B are schematic diagrams showing an example of setting of the ejection coverage area of ​​each nozzle opening. [Figure 8] 10A and 10B are schematic diagrams showing an example of setting of the ejection coverage area of ​​each nozzle opening. [Figure 9] FIG. 10 is a block diagram showing an example of the flow of objects to be sorted in the optical sorting machine according to the second embodiment when the rate of defective products is low. [Figure 10] FIG. 10 is a block diagram showing an example of the flow of objects to be sorted in the optical sorting machine according to the second embodiment when the rate of defective products mixed in is medium. [Figure 11] FIG. 10 is a block diagram showing an example of the flow of objects to be sorted in the optical sorting machine according to the second embodiment when the rate of defective items mixed in is high. DETAILED DESCRIPTION OF THE INVENTION

[0022] FIG. 1 is a block diagram illustrating an example of the flow of objects 90 through an optical sorter (hereinafter simply referred to as a sorter) 10 according to a first embodiment when the rate of defective items is low (e.g., 10% or less). In this embodiment, the sorter 10 is used to sort defective items from rice grains (more specifically, brown rice) as an example of the objects 90. Here, the term "defective items" refers to low-quality rice (e.g., immature grains, discolored grains, etc.) that are undesirable as products and foreign objects (e.g., other grains, pebbles, mud, glass fragments, etc.). The sorter 10 may be used to sort only low-quality rice or foreign objects. Furthermore, the objects 90 are not limited to brown rice or polished rice, but may be any granular object. For example, the objects 90 may be unhulled rice, wheat grains, pulses (e.g., soybeans, chickpeas, edamame), resin (e.g., pellets), rubber fragments, etc.

[0023] As shown in Fig. 1, the sorting machine 10 according to the first embodiment includes a primary sorting system 20a (hereinafter simply referred to as the primary system 20a), a secondary sorting system 20b (hereinafter simply referred to as the secondary system 20b), a tertiary sorting system 20c (hereinafter simply referred to as the tertiary system 20c), switching valves 21-26, a controller 27, a non-defective product hopper 28, and a defective product container 29. As will be described later, each of the primary to tertiary systems 20a-20c sorts the objects 90 to be sorted into non-defective products and defective products by spraying air 52. The switching valves 21-26 switch the discharge destinations of the objects 90 to be sorted (the objects 90 to be discharged as non-defective products and the objects 90 to be discharged as defective products) sorted in each of the primary to tertiary systems 20a-20c. The discharge destination of each of the switching valves 21-26 can be set via a user interface of the sorter 10. The controller 27 controls the overall operation of the sorter 10. The functions of the controller 27 may be realized by a CPU executing a predetermined program, by a dedicated circuit, or by a combination of these. The functions of the controller 27 may be realized by a single integrated device. For example, the functions of the controller 27 may be realized by a single CPU. Alternatively, the functions of the controller 27 may be distributed and arranged in at least two devices. The non-defective product hopper 28 stores the objects 90 to be sorted that have been finally sorted as non-defective products (i.e., products). The defective product container 29 stores the objects 90 to be sorted that have been finally sorted as defective products.

[0024] The primary to tertiary systems 20a to 20c have the same device configuration. Therefore, the following will describe the schematic configuration of the primary system 20a, which represents the primary to tertiary systems 20a to 20c, with reference to Fig. 2. As shown in Fig. 2, the primary system 20a includes light sources 31 and 32, optical sensors 41 and 42, a sorting device 50, a storage tank 71, a feeder 72, a chute 73, a first discharge gutter 76, and a second discharge gutter 77.

[0025] The storage tank 71 temporarily stores the objects to be sorted 90. The feeder 72 supplies the objects to be sorted 90 stored in the storage tank 71 onto a chute 73, which is an example of an object transfer means. The objects to be sorted 90 supplied onto the chute 73 slide downward on the chute 73 and fall from the lower end of the chute 73. The chute 73 has a predetermined width that allows a large number of objects to be sorted 90 to fall simultaneously. In the following description, the direction in which the objects to be sorted 90 are transferred after falling from the chute 73 (in other words, the direction in which the objects to be sorted 90 fall) is also referred to as the transfer direction D1. A direction intersecting the transfer direction D1 is also referred to as the intersecting direction D2. The intersecting direction D2 may be a direction perpendicular to the transfer direction D1.

[0026] The light source 31 is disposed on one side (also referred to as the front side) of a transfer path 95 for the objects 90 to be sorted (in other words, the falling trajectory of the objects 90 to be sorted), and the light source 32 is disposed on the other side (also referred to as the rear side) of the transfer path 95 for the objects 90 to be sorted. The light sources 31 and 32 irradiate the objects 90 to be sorted (i.e., the objects 90 that have slid down the chute 73) with light beams 33 and 34, respectively. In this embodiment, the light sources 31 and 32 each include a plurality of LEDs that emit red light, a plurality of LEDs that emit green light, a plurality of LEDs that emit blue light, and a plurality of LEDs that emit near-infrared light. However, the specifications of the light sources 31 and 32 (e.g., the number, light emission type, wavelength range of the light beams 33 and 34, etc.) are not particularly limited. For example, the light sources 31 and 32 may each include only LEDs that emit visible light or only LEDs that emit near-infrared light. Alternatively, the LEDs that emit near-infrared light may be arranged on only one of the front side and the rear side, or one of the light sources 31 and 32 may be omitted.

[0027] The optical sensor 41 is disposed on the front side, and the optical sensor 42 is disposed on the rear side. The optical sensors 41, 42 detect light emitted from the light sources 31, 32 and associated with the objects 90 to be sorted. Specifically, the front-side optical sensor 41 can detect light 33 emitted from the front-side light source 31 and reflected by the objects 90 to be sorted, and light 34 emitted from the rear-side light source 32 and transmitted through the objects 90 to be sorted. The rear-side optical sensor 42 can detect light 34 emitted from the rear-side light source 32 and reflected by the objects 90 to be sorted, and light 33 emitted from the front-side light source 31 and transmitted through the objects 90 to be sorted.

[0028] In this embodiment, the optical sensors 41, 42 are each a color CCD sensor and a near-infrared sensor, and each include a plurality of linearly arranged light-receiving elements 43, 44 (see FIG. 3). The plurality of light-receiving elements 43, 44 are arranged in the intersecting direction D2. This allows the optical sensors 41, 42 to simultaneously capture images of a large number of objects 90 being transported across a predetermined width of the chute 73. The specifications of the optical sensors 41, 42 are not particularly limited and can be determined arbitrarily depending on the specifications of the light sources 31, 32. Alternatively, one of the optical sensors 41, 42 may be omitted.

[0029] The outputs from the optical sensors 41 and 42, i.e., analog signals representing the intensity of the detected light, are amplified by an AC / DC converter (not shown) at a predetermined gain and then converted into digital signals. These digital signals (in other words, gradation values ​​corresponding to the analog signals) are input to the controller 27 (see FIG. 1). The controller 27 determines whether the object 90 is a good product or a defective product based on the detection results of the input light (i.e., the image). Specifically, the controller 27 compares the gradation values ​​of the image corresponding to a color (wavelength) predetermined for each type of defective product with a threshold value predetermined for each type of defective product, and determines whether the object 90 is a good product or a defective product based on the magnitude relationship between the gradation values. This determination may be made using an image based on at least one of the reflected light 33, the transmitted light 34, and the light obtained by combining the reflected light 33 and the transmitted light 34 detected by the optical sensor 41, and the reflected light 34, the transmitted light 33, and the light obtained by combining the reflected light 33 and the transmitted light 34 detected by the optical sensor 42. Furthermore, for a specific type of defective product, it may be determined whether the object to be sorted 90 is a good product or a defective product based on the size of the defective portion (pixel representing the defect).

[0030] The sorting device 50 includes a plurality of nozzles 51 for spraying air 52. The plurality of nozzles 51 are arranged in the cross direction D2 (see FIG. 3). Each of the nozzles 51 includes a plurality of openings 53 for spraying air 52. The plurality of openings 53 are arranged in the cross direction D2 (see FIG. 3). In this embodiment, the openings 53 have a rectangular shape with the transfer direction D1 as the short side direction and a direction perpendicular to the transfer direction D1 as the long side direction. In this embodiment, a plurality of nozzles 51 having a plurality of openings 53 are used, but in an alternative embodiment, a single nozzle 51 having a plurality of openings 53 may be used. In a further alternative embodiment, a plurality of nozzles 51 having a single opening 53 may be used.

[0031] The sorting device 50 selectively sprays air 52 toward a specific object 90 from any of the openings 53 of any of the nozzles 51. As will be described in detail later, an air tank is connected to each of the openings 53 of each nozzle 51 via a valve. At least one valve is selectively opened in response to a control signal from the controller 27, whereby air 52 is selectively sprayed toward the object 90 from the opening 53 corresponding to the at least one valve. More specifically, each of the openings 53 is assigned a spray range for each detection position of the object 90 in the cross direction D2. Each of the openings 53 sprays air 52 when the specific object 90 is located within the corresponding spray range or when a predetermined position (e.g., the center) of the specific object 90 is located within the corresponding spray range. In this way, each of the multiple openings 53 is assigned a range for spraying air 52 for each detection position of the object 90 in the cross direction D2. In practice, the ejection coverage area is defined by the position on the image in the cross direction D2 input to the controller 27.

[0032] The "specific objects 90" to which air 52 should be sprayed are either objects 90 judged to be good or objects 90 judged to be defective, and it is set in advance which objects 90 to spray air 52 on. The operating mode in which air is sprayed on objects 90 judged to be defective is also called the normal mode. The operating mode in which air is sprayed on objects 90 judged to be good is also called the reverse blow mode.

[0033] The specific objects 90 to which the air 52 is sprayed (for example, objects 90 determined to be defective) are blown away by the air 52, deviate from the falling trajectory from the chute 73 (i.e., transfer path 95), and are guided to the second discharge gutter 77 (shown as objects 91 in FIG. 2). On the other hand, the air 52 is not sprayed to objects 90 other than the specific objects 90 (if the specific objects 90 are objects 90 determined to be defective, they are objects 90 determined to be non-defective, hereinafter also referred to as "other objects 90"). Therefore, the other objects 90 are guided to the first discharge gutter 76 without changing their falling trajectory (shown as objects 92 in FIG. 2). In this way, the objects 90 introduced into the storage tank 71 are sorted into objects 90 determined to be non-defective and objects 90 determined to be defective. In such a sorting process, the jet of air 52 may blow away other objects 90 around a particular object 90 to be sorted, resulting in the objects being removed as a result.

[0034] Note that instead of the configuration in which air 52 is sprayed toward the objects 90 after they have fallen from the chute 73, air 52 may be sprayed toward the objects 90 sliding on the chute 73, thereby changing the transport path of the objects 90. Also, a belt conveyor may be used as the object transport means instead of the chute 73. In this case, air 52 may be sprayed toward the objects 90 dropping from one end of the belt conveyor. Alternatively, air 52 may be sprayed toward the objects 90 being transported on the belt conveyor.

[0035] Returning to FIG. 1 for further explanation, the primary system 20a is operated in normal mode. That is, in the primary system 20a, objects 90 determined to be non-defective are discharged into the first discharge gutter 76 without receiving the jet of air 52. On the other hand, objects 90 determined to be defective are discharged into the second discharge gutter 77 after receiving the jet of air 52. FIG. 1 illustrates whether the "non-defective" and "defective" objects discharged from each of the primary to tertiary systems 20a to 20c are discharged into either the first discharge gutter 76 or the second discharge gutter 77, depending on whether they are in normal mode or reverse striking mode. Specifically, of the objects 90 discharged from each of the first to third systems 20a to 20c, the objects 90 discharged into the first discharge gutter 76 without receiving the jet of air 52 (for example, "good products" discharged from the first system 20a) are shown on the left, and the objects 90 discharged into the second discharge gutter 77 after receiving the jet of air 52 (for example, "defective products" discharged from the first system 20a) are shown on the right. This also applies to Figures 5, 6, and 9 to 11, which will be described later.

[0036] The objects to be sorted 90 discharged as non-defective products from the primary system 20a via the first discharge gutter 76 are discharged into the non-defective product hopper 28 via the switching valve 21. The objects to be sorted 90 stored in the non-defective product hopper 28 are then supplied to equipment (e.g., a weighing and packaging device) installed in the subsequent process. The objects to be sorted 90 discharged as defective products from the primary system 20a via the second discharge gutter 77 are fed into the secondary system 20b via the switching valve 22.

[0037] The secondary system 20b operates in normal mode. Accordingly, in the secondary system 20b, the objects 90 determined to be non-defective are discharged into the first discharge conduit 76 without receiving the air 52. On the other hand, the objects 90 determined to be defective are discharged into the second discharge conduit 77 with the air 52. The objects 90 discharged from the first discharge conduit 76 as non-defective are then re-introduced into the primary system 20a via the switching valve 23. In other words, non-defective items included in the objects 90 discharged from the primary system 20a as defective items are given the opportunity to be re-sorted in the primary system 20a and ultimately collected as non-defective items in the non-defective item hopper 28 from the primary system 20a. This improves the yield of non-defective items. The objects 90 discharged from the second discharge conduit 77 as defective are then input into the tertiary system 20c via the switching valve 24.

[0038] The tertiary system 20c is operated in reverse blow mode. Therefore, in the tertiary system 20c, the objects 90 determined to be defective are discharged into the first discharge conduit 76 without receiving the air 52. On the other hand, the objects 90 determined to be non-defective are discharged into the second discharge conduit 77 with the air 52. The objects 90 discharged as defective from the first discharge conduit 76 are then discharged into the defective product container 29 via the switching valve 25. The objects 90 discharged as non-defective from the second discharge conduit 77 are then re-introduced into the secondary system 20b via the switching valve 26. In other words, non-defective items included in the objects 90 discharged as defective from the secondary sorting system 20b are re-sorted in the secondary system 20b, re-introduced into the primary system 20a, and finally given the opportunity to be collected as non-defective items from the primary system 20a. This further improves the yield of non-defective items.

[0039] In the present embodiment of the above-described sorter 10, the first to third systems 20a to 20c are configured to share the chute 73, the light sources 31, 32, and the optical sensors 41, 42. Specifically, as shown in Fig. 3, the single chute 73 is divided by partition walls 74, 75 extending in the transfer direction D1 into a first system area 73a for the first system 20a, a second system area 73b for the second system 20b, and a third system area 73c for the third system 20c.

[0040] The light source 31 is a light source unit in which a plurality of light-emitting elements 35 are arranged in the intersecting direction D2 on a single substrate. The light-emitting elements 35 are arranged throughout the primary to tertiary system regions 73a to 73c and can irradiate light 33 onto any of the objects 90 dropping from each of the primary to tertiary system regions 73a to 73c. ​​Similarly, the light source 32 is a light source unit in which a plurality of light-emitting elements 36 are arranged in the intersecting direction D2 on a single substrate. The light-emitting elements 36 are arranged throughout the primary to tertiary system regions 73a to 73c.

[0041] As described above, the optical sensors 41 and 42 are line sensors in which a plurality of light receiving elements 43 and 44 are arranged in the intersecting direction D2. The light receiving elements 43 and 44 are arranged across the entire first to third system regions 73a to 73c. ​​Therefore, the light receiving elements 43 and 44 can detect the light 33 and 44 associated with any of the objects 90 falling from each of the first to third system regions 73a to 73c.

[0042] As described above, the sorting device 50 is equipped with a plurality of nozzles 51 arranged in the intersecting direction D2. The nozzles 51 are arranged throughout the first to third system regions 73a to 73c. ​​Therefore, the sorting device 50 can spray air 52 onto any of the objects to be sorted 90 dropping from each of the first to third system regions 73a to 73c.

[0043] This configuration in which the chute 73, the light sources 31, 32, and the optical sensors 41, 42 are shared can simplify and downsize the device configuration of the sorter 10. However, at least some of the chute 73, the light sources 31, 32, and the optical sensors 41, 42 may be individually provided for each of the first to third systems 20a to 20c.

[0044] 4, the sorting device 50 includes, in addition to the nozzle 51 described above, an air tank 54, a pressure regulating valve (regulator) 55, a manifold 56, a first pipe 57, a second pipe 58, and a third pipe 59. The air tank 54 is connected to the nozzle 51 so as to be fluidically connected thereto via the first pipe 57, the pressure regulating valve 55, the second pipe 58, the manifold 56, and the third pipe 59.

[0045] The air tank 54 stores air compressed by a compressor (not shown). The pressure regulating valve 55 regulates (decreases or increases) the pressure of the air 52 supplied from the air tank 54 to the nozzle 51 to a set pressure value. The controller 27 is configured to send a control signal to the pressure regulating valve 55 based on an input to a user interface (not shown) of the sorting machine 10, thereby changing the set pressure value of the pressure regulating valve 55. The air tank 54 and the pressure regulating valve 55 are connected to each other by a first pipe 57.

[0046] A plurality of manifolds 56 are connected to one pressure regulating valve 55 via a plurality of second pipes 58. Each of the manifolds 56 has one inlet, a plurality of outlets, and passages that branch downstream of the one inlet and are connected to the plurality of outlets (none of which are shown). Each of the branched passages is provided with a valve (not shown in FIG. 4; shown as valves 591 to 593 in FIGS. 7 and 8) for opening and closing the passage in response to a control signal from the controller 27.

[0047] A plurality of manifolds 56 are connected to one nozzle 51 via third pipes 59 connected to each of the outlets of the manifolds 56. The total number of outlets of the plurality of manifolds 56 connected to one nozzle 51 is equal to the number of openings 53 of the one nozzle 51. In other words, downstream The portions on the nozzle 51 side form flow paths that are independent of each other.

[0048] Each of the primary to tertiary systems 20a to 20c includes the respective components of the sorting device 50. Specifically, the air tank 54 includes a primary system air tank 54a, a secondary system air tank 54b, and a tertiary system air tank 54c. Similarly, the pressure regulating valve 55 includes a primary system pressure regulating valve 55a, a secondary system pressure regulating valve 55b, and a tertiary system pressure regulating valve 55c, the manifold 56 includes a primary system manifold 56a, a secondary system manifold 56b, and a tertiary system manifold 56c, and the nozzle 51 includes a primary system nozzle 51a, a secondary system nozzle 51b, and a tertiary system nozzle 51c.

[0049] By providing a pressure regulating valve 55 for each of the primary, secondary, and tertiary systems 20a to 20c as in this embodiment, the injection pressure of the air 52 can be easily controlled to a desired value for each of the primary, secondary, and tertiary systems 20a to 20c. However, if the injection pressure may be fixed, different injection pressures may be achieved by, for example, varying the cross-sectional area of ​​the flow path. Furthermore, by providing an air tank 54 for each of the primary, secondary, and tertiary systems 20a to 20c as in this embodiment, even if the air consumption varies among the primary, secondary, and tertiary systems 20a to 20c, the air 52 can be stably injected at an appropriate injection pressure in each of the primary, secondary, and tertiary systems 20a to 20c. This reduces sorting errors and improves sorting accuracy. However, a single air tank 54 may be shared by the primary, secondary, and tertiary systems 20a to 20c.

[0050] In the above-described sorting machine 10, at least two of the first to third systems 20a to 20c are configured to be operable so that settings (hereinafter also referred to as spray settings) that affect the spray range of air 52 against specific objects 90 (i.e., objects 90 to which air 52 should be sprayed) are different from each other. Such a configuration will be described below.

[0051] In this embodiment, the injection setting includes setting the injection pressure of the air 52. The higher the injection pressure of the air 52, the wider the spatial range in which the trajectory of the specific object 90 can be changed to such an extent that the specific object 90 reaches the second discharge gutter 77, in any direction intersecting the injection direction of the air 52. In other words, even when the air 52 is injected from openings 53 of the same size, the higher the injection pressure of the air 52, the wider the injection range of the air 52 against the specific object 90. When the injection range of the air 52 is wider, the specific object 90 can be more reliably removed (i.e., guided to the second discharge gutter 77) and the purity of the other objects 90 discharged to the first discharge gutter 76 can be increased (the mixing rate of the specific object 90 can be reduced). On the other hand, when the spray range of the air 52 is widened, the probability that other objects 90 adjacent to the specific object 90 will be removed as a result increases, and the amount of other objects 90 discharged into the first discharge gutter 76 (if the other objects 90 are objects 90 determined to be non-defective, the yield) decreases. In other words, when the spray range of the air 52 is widened, the amount of other objects 90 discharged decreases but the purity increases, and when the spray range of the air 52 is narrowed, the purity of the other objects 90 decreases but the amount of other objects 90 discharged increases.

[0052] In the sorting machine 10, attention is paid to such a correlation between the spray range of the air 52 (which is controlled by the spray pressure in this embodiment) and the purity and amount of the other objects to be sorted 90, and the spray pressure of the air 52 is appropriately set for each of the first to third systems 20a to 20c. Specifically, in a system where it is desired to prioritize the purity of the other objects to be sorted 90, the spray pressure of the air 52 is set relatively high, and in a system where it is desired to prioritize the discharge amount of the other objects to be sorted 90, the spray pressure of the air 52 is set relatively low.

[0053] For example, when the flow of objects 90 in the sorter 10 is as shown in Fig. 1, the spray pressure of the air 52 in the primary line 20a may be set higher than the spray pressure of the air 52 in the secondary line 20b and the tertiary line 20c. In other words, the spray settings may be set so that the spray range of the air 52 in the primary line 20a is wider than the spray range of the air 52 in the secondary line 20b and the tertiary line 20c. The spray pressures in the secondary line 20b and the tertiary line 20c may be the same or different.

[0054] According to this setting, in the primary system 20a operated in the normal mode, defective products are reliably removed by the relatively high injection pressure of the air 52, and high-purity non-defective products can be collected in the non-defective product hopper 28. Furthermore, in the secondary system 20b operated in the normal mode, the relatively low injection pressure prevents non-defective products from being removed along with the defective products. This increases the number of non-defective products included in the objects 90 discharged as non-defective products, further improving yield. Note that in the secondary system 20b, the relatively low injection pressure increases the possibility of defective products being mixed in with the objects 90 discharged as non-defective products. However, the objects 90 discharged as non-defective products from the secondary system 20b are re-introduced into the primary system 20a, which can recover non-defective products with high purity. This ensures high purity of non-defective products throughout the sorting machine 10.

[0055] Furthermore, in the tertiary system 20c operated in the reverse blow mode, the relatively low injection pressure prevents defective products from being removed along with non-defective products. This increases the purity of the objects 90 discharged as non-defective from the secondary system 20b, ensuring a high purity of non-defective products throughout the sorting machine 10. Furthermore, this prevents defective products from being removed along with non-defective products and reintroduced into the secondary system 20b, resulting in a loop between the secondary system 20b and the tertiary system 20c. While the relatively low injection pressure in the tertiary system 20c increases the probability of non-defective products being mixed in with the objects 90 recovered as defective, the number of non-defective products contained in the objects 90 that are sorted twice as defective in the primary system 20a and the secondary system 20b and then input into the tertiary system 20c is small. Therefore, this problem does not significantly affect the yield of the sorting machine 10 as a whole.

[0056] FIG. 5 is a block diagram showing an example of the flow of the objects 90 in the sorting machine 10 when the defective product inclusion rate is moderate (e.g., 60% or less). This flow of the objects 90 is achieved by the controller 27 sending control signals to the switching valves 21-26, which in turn switch the discharge destinations of the objects 90 discharged into the first discharge conduit 76 and the second discharge conduit 77. In the example of FIG. 5, similar to the example of FIG. 1, the primary system 20a and the secondary system 20b are operated in normal mode, and the tertiary system 20c is operated in reverse mode. The objects 90 discharged as non-defective products from the primary system 20a via the first discharge conduit 76 are fed into the secondary system 20b via the switching valve 21. The objects 90 discharged as defective products from the primary system 20a via the second discharge conduit 77 are fed into the tertiary system 20c via the switching valve 22.

[0057] The objects to be sorted 90 discharged as non-defective products from the secondary system 20b via the first discharge conduit 76 are discharged into the non-defective product hopper 28 via the switching valve 23. The objects to be sorted 90 discharged as defective products from the secondary system 20b via the second discharge conduit 77 are re-introduced into the primary system 20a via the switching valve 24. The objects to be sorted 90 discharged as defective products from the tertiary system 20c via the first discharge conduit 76 are discharged into the defective product container 29 via the switching valve 25. The objects to be sorted 90 discharged as non-defective products from the tertiary system 20c via the second discharge conduit 77 are re-introduced into the primary system 20a via the switching valve 26. According to this flow of the objects to be sorted 90, non-defective products included in the objects to be sorted 90 that are discharged as defective products from the secondary system 20b, and non-defective products included in the objects to be sorted 90 that are discharged as non-defective products from the tertiary system 20c, are given the opportunity to be re-introduced into the primary system 20a and ultimately collected as non-defective products from the secondary system 20b into the non-defective product hopper 28. This makes it possible to improve the yield of non-defective products.

[0058] In the example shown in FIG. 5 , the injection pressure of the air 52 in the secondary system 20b may be set higher than the injection pressure of the air 52 in the primary system 20a and the tertiary system 20c. The injection pressures of the primary system 20a and the tertiary system 20c may be the same or different. With this setting, in the primary system 20a operating in normal mode, the relatively low injection pressure prevents non-defective products from being removed along with defective products. This increases the number of non-defective products included in the sorted objects 90 that are discharged as non-defective products. Since the non-defective products included in the sorted objects 90 that are discharged as non-defective products are re-sorted in the secondary system 20b and then recovered as non-defective products, increasing the number of non-defective products included in the sorted objects 90 that are discharged as non-defective products from the primary system 20a further improves the yield.

[0059] Furthermore, in the secondary system 20b operated in normal mode, defective products can be reliably removed by the relatively high injection pressure of air 52, allowing high-purity non-defective products to be recovered. Although the relatively low injection pressure of the primary system 20a increases the likelihood of defective products being mixed in with the objects 90 discharged as non-defective from the primary system 20a, the objects 90 discharged as non-defective from the primary system 20a are fed into the secondary system 20b, which can recover high-purity non-defective products, ensuring high purity for the sorting machine 10 as a whole. Furthermore, the relatively high injection pressure of the secondary system 20b increases the likelihood of non-defective products being removed along with defective products. However, the objects 90 discharged as non-defective from the secondary system 20b are re-introduced into the primary system 20a, where non-defective products are prevented from being removed along with the defective products. Therefore, the relatively high injection pressure of the secondary system 20b does not result in a decrease in the yield of the sorting machine 10 as a whole.

[0060] Furthermore, in the tertiary system 20c operated in the reverse blow mode, the relatively low injection pressure prevents defective products from being removed along with non-defective products. This prevents defective products from being removed along with non-defective products and re-introduced into the primary system 20a, resulting in a loop between the primary system 20a and the tertiary system 20c via the secondary system 20b. Note that the relatively low injection pressure in the tertiary system 20c increases the probability that non-defective products will be mixed in with the objects 90 to be sorted and recovered as defective. However, non-defective products are less likely to be mixed in with the objects 90 to be sorted and input into the tertiary system 20c, i.e., the objects 90 to be sorted and discharged as defective from the primary system 20a. Therefore, the number of non-defective products contained in the objects 90 to be sorted and input into the tertiary system 20c is small. Therefore, this problem does not significantly affect the yield of the sorter 10 as a whole.

[0061] FIG. 6 is a block diagram showing an example of the flow of the objects 90 in the sorting machine 10 when the defective product mix rate is high (e.g., 60% or more). This flow of the objects 90 is achieved by the controller 27 sending control signals to the switching valves 21-26, which in turn switch the discharge destinations of the objects 90 discharged into the first discharge conduit 76 and the second discharge conduit 77. In the example shown in FIG. 6, the primary system 20a operates in reverse mode, and the secondary system 20b and the tertiary system 20c operate in normal mode. The objects 90 discharged as defective products from the primary system 20a via the first discharge conduit 76 are discharged into the defective product container 29 via the switching valve 21. The objects 90 discharged as non-defective products from the primary system 20a via the second discharge conduit 77 are fed into the secondary system 20b via the switching valve 22.

[0062] The objects to be sorted 90 discharged as non-defective products from the secondary system 20b via the first discharge gutter 76 are input into the tertiary system 20c via the switching valve 23. The objects to be sorted 90 discharged as defective products from the secondary system 20b via the second discharge gutter 77 are re-input into the primary system 20a via the switching valve 24. The objects to be sorted 90 discharged as non-defective products from the tertiary system 20c via the first discharge gutter 76 are discharged into the non-defective product hopper 28 via the switching valve 25. The objects to be sorted 90 discharged as defective products from the tertiary system 20c via the second discharge gutter 77 are re-input into the secondary system 20b via the switching valve 26. According to this flow of the objects to be sorted 90, non-defective products included in the objects to be sorted 90 that are discharged as defective products from the secondary system 20b, and non-defective products included in the objects to be sorted 90 that are discharged as defective products from the tertiary system 20c are given the opportunity to be re-introduced into the primary system 20a and the secondary system 20b, respectively, and finally collected as non-defective products from the tertiary system 20c into the non-defective product hopper 28. This makes it possible to improve the yield of non-defective products.

[0063] In the example shown in FIG. 6, the injection pressure of the air 52 in the tertiary system 20c may be set higher than the injection pressure of the air 52 in the primary system 20a and the secondary system 20b. The injection pressures of the primary system 20a and the secondary system 20b may be the same or different. With this setting, in the primary system 20a operating in the reverse impact mode, the relatively low injection pressure prevents defective products from being removed along with non-defective products. Therefore, even if a high proportion of defective products are input into the primary system 20a, the purity of the non-defective products among the objects 90 to be sorted can be suitably ensured. In addition, since the possibility of defective products being mixed in with the sorted items 90 that are discharged as good products is reduced, the defective products are removed along with the good products and re-introduced into the secondary system 20b, which prevents looping between the primary system 20a and the secondary system 20b, or between the primary system 20a and the tertiary system 20c via the secondary system 20b.

[0064] Furthermore, in the secondary system 20b operated in the normal mode, the relatively low injection pressure prevents non-defective products from being removed together with defective products, which increases the amount of non-defective products fed into the tertiary system 20c, which ultimately collects the non-defective products in the non-defective product hopper 28, further improving the yield.

[0065] Furthermore, in the tertiary system 20c, which is operated in normal mode and ultimately collects non-defective products, defective products are reliably removed by the relatively high-pressure air 52, allowing highly pure non-defective products to be collected in the non-defective product hopper 28. Furthermore, due to the relatively high injection pressure of the tertiary system 20c, there is an increased possibility that non-defective products will be mixed in with the objects 90 to be sorted and discharged as defective products from the tertiary system 20c. However, non-defective products included in the objects 90 to be sorted and discharged as defective products from the tertiary system 20c are re-introduced into the secondary system 20b, giving them another opportunity to be finally collected as non-defective products from the tertiary system 20c. Therefore, this problem does not result in a decrease in the yield of the sorter 10 as a whole.

[0066] According to the above-described sorting machine 10, the probability of the objects 90 being entrained and removed in the flow of the objects 90 passing through the primary to tertiary systems 20a to 20c can be appropriately controlled for each of the primary to tertiary systems 20a to 20c. Therefore, the desired sorting accuracy and yield can be easily achieved. Furthermore, it is also possible to achieve both a high level of purity and a high yield of non-defective products.

[0067] Furthermore, according to the sorting machine 10, the controller 27 is configured to be able to change the injection settings of each of the primary to tertiary systems 20a to 20c, i.e., the setting of the injection pressure of the air 52, by controlling the pressure adjustment valve 55. Therefore, as described above, the user can appropriately change the injection pressure setting for each of the primary to tertiary systems 20a to 20c depending on the rate of defective products in the objects to be sorted 90. The injection pressure setting can be changed as appropriate not only depending on the rate of defective products in the objects to be sorted 90 but also depending on the properties of the objects to be sorted 90 (for example, specific gravity), or the required sorting accuracy and / or yield. This improves user convenience and the versatility of the sorting machine 10.

[0068] In an alternative embodiment, the jetting settings for each of the primary to tertiary systems 20a to 20c include a setting for the jetting period of the air 52 (i.e., the duration of jetting). The longer the jetting period, the wider the jetting range of the air 52 in the transfer direction D1 relative to the objects 90 in a coordinate system that moves together with the objects 90 being transferred. A wider jetting range in the transfer direction D1 can more reliably remove specific objects 90 (objects 90 to which the air 52 should be jetted), while increasing the probability that other objects 90 (objects 90 to which the air 52 should not be jetted) will be removed as a result. For example, in the example shown in FIG. 1 , the jetting period of the air 52 in the primary system 20a may be set longer than the jetting period of the air 52 in the secondary system 20b and the tertiary system 20c in order to make the jetting range of the air 52 in the primary system 20a wider than the jetting range of the air 52 in the secondary system 20b and the tertiary system 20c. The injection periods of the secondary system 20b and the tertiary system 20c may be the same or different. Even with this configuration, it is possible to control the injection range of the air 52 for each of the primary to tertiary systems 20a to 20c, and therefore the probability of collateral removal. Although detailed explanation will be omitted, even in the example shown in FIG. 5 or 6, it is possible to control the injection range of the air 52 based on the injection period for each of the primary to tertiary systems 20a to 20c. The controller 27 may be configured to be able to change the setting of the injection period for each of the primary to tertiary systems 20a to 20c.

[0069] In a further alternative embodiment, the jetting settings set for each of the primary to tertiary systems 20a to 20c include a setting of a jetting coverage area, i.e., a correspondence between each detection position of a specific object 90 in the cross direction D2 and the openings 53 that should jet air 52 toward the specific object 90. Specifically, the setting of such jetting coverage areas can be, for example, a setting of whether or not the jetting coverage areas of adjacent openings 53 overlap. When the jetting coverage areas overlap, there may be cases where air 52 is jetted from a predetermined number of openings 53 (e.g., one) and cases where air 52 is jetted from a greater number of openings 53 (e.g., two). However, when the jetting coverage areas do not overlap, there is no change in the number of openings 53 that jet air 52 toward one specific object 90. This point will be described in detail below. In the following explanation, it is assumed that when the center of a defective part of a defective product is located at a predetermined detection position, air 52 is sprayed from an opening 53 whose spray range includes the detection position.

[0070] 7 and 8 are schematic diagrams showing an example of setting allocation of ejection coverage areas. For convenience of explanation, in FIGS. 7 and 8, it is assumed that one nozzle 51 has three openings 531-533. Three valves 591-593 arranged in a manifold 56 are connected to the three openings 531-533, respectively. In FIGS. 7 and 8, each grid represents a pixel that constitutes an image 80 input to the controller 27.

[0071] In the example shown in FIG. 7, there is an overlapping region where the jetting ranges overlap. Specifically, as shown in FIG. 7, jetting ranges 831 to 833 are respectively associated with the openings 531 to 533. In FIG. 7, the correspondence between the openings 531 and 533 and the associated jetting ranges 831 and 833 is indicated by a dashed-dotted line, and the correspondence between the opening 532 and the associated jetting range 832 is indicated by a dotted line. As shown in FIG. 7, the two jetting ranges 831 and 832 corresponding to the two adjacent openings 531 and 532, respectively, overlap each other in an overlapping region 841. Similarly, the two jetting ranges 832 and 833 corresponding to the two adjacent openings 532 and 533, respectively, overlap each other in an overlapping region 842.

[0072] When the center of the defective part is located at pixel 82, pixel 82 belongs only to assigned jetting range 832, and therefore air 52 is ejected only from opening 532 corresponding to assigned jetting range 832. On the other hand, when the center of the defective part is located at pixel 81, pixel 81 belongs to overlapping region 841 (that is, it belongs to both assigned jetting ranges 831 and 832), and therefore air 52 is ejected from two openings 531 and 532 corresponding to assigned jetting ranges 831 and 832, respectively. In this way, when the assigned jetting ranges are set to overlap, the number of openings 53 that eject air 52 onto one specific object 90 to be sorted varies.

[0073] On the other hand, in the example shown in FIG. 8, there is no overlapping area. Specifically, as shown in FIG. 8, spraying ranges 861 to 863 are assigned to openings 531 to 533, respectively. The spraying ranges 861 to 863 are set so as not to overlap one another. In this case, regardless of which detection position the center of a defective part is located at, the detected position of the center of the defective part belongs to only one spraying range. For example, when the center of the defective part is located at pixel 84, pixel 84 belongs only to spraying range 862, and therefore air 52 is sprayed only from openings 532 corresponding to spraying range 862. Note that while FIGS. 7 and 8 illustrate cases in which air 52 is sprayed from only one opening 53 and cases in which air 52 is sprayed from two openings 53, the number of openings 53 spraying air 52 against one specific object 90 can be set as desired depending on the setting of the overlapping areas. For example, a case in which the air 52 is jetted from two openings 53 and a case in which the air 52 is jetted from three openings 53 may be set.

[0074] As the number of openings 53 that spray air 52 at one specific object 90 increases, the spray range of air 52 becomes wider in the cross direction D2. Therefore, when a spray area is set where an overlapping area exists, the frequency with which the air spray area becomes wider increases compared to when a spray area is set where no overlapping area exists. This means that while there is a higher probability of more reliably removing a specific object 90 (an object 90 to which air 52 should be sprayed), there is also a higher probability of other objects 90 (objects 90 to which air 52 should not be sprayed) being removed as a result.

[0075] For example, in the example shown in FIG. 1 , to increase the frequency with which the spray range of the air 52 in the primary system 20a is wider than the spray ranges of the air 52 in the secondary system 20b and the tertiary system 20c, the spray range of the primary system 20a may be set so that there is an overlapping area, and the spray ranges of the secondary system 20b and the tertiary system 20c may be set so that there is no overlapping area. Alternatively, the spray range of the primary system 20a may be set so that there is an overlapping area, and the spray ranges of the secondary system 20b and the tertiary system 20c may be set so that there is an overlapping area that is narrower than the primary system 20a. The sizes of the overlapping areas in the secondary system 20b and the tertiary system 20c may be the same or different. This also increases the frequency with which the spray range of the air 52 in the primary system 20a is wider than the spray ranges of the air 52 in the secondary system 20b and the tertiary system 20c. As is clear from this explanation, the injection setting set for each of the primary to tertiary systems 20a to 20c may be a setting related to increasing or decreasing the frequency at which the air injection range widens. Although detailed explanation will be omitted, even in the example shown in Fig. 5 or 6, it is possible to control the frequency at which the injection range of the air 52 widens for each of the primary to tertiary systems 20a to 20c based on the injection range assigned to each system. The controller 27 may be configured to be able to change the setting of the injection range assigned to each of the primary to tertiary systems 20a to 20c.

[0076] In a further alternative embodiment, the spray settings set for each of the primary to tertiary systems 20a to 20c include the structure of the nozzle 51. The spray range of the air 52 can also be controlled by the structure of the nozzle 51. For example, a nozzle structure in which the cross-sectional area of ​​the nozzle 51 gradually decreases from the inlet (connection port to the third pipe 59) of the nozzle 51 toward the outlet (opening 53) of the nozzle 51 can increase the spray pressure of the air 52. Alternatively, the spray range of the air 52 can be widened by increasing the pressure of the air 52 supplied to the nozzle 51 and enlarging the opening 53 of the nozzle 51. Alternatively, the spray period can be extended by reducing the cross-sectional area of ​​the flow path from the inlet to the outlet of the nozzle 51. For example, in the example shown in FIG. 1, the nozzle 51 in the primary system 20a may have a structure that widens the spray range of the air 52 compared to the nozzles 51 in the secondary system 20b and the tertiary system 20c. The structures of the nozzles 51 in the secondary system 20b and the tertiary system 20c may be the same or different. Although detailed description will be omitted, even in the example shown in FIG. 5 or 6, the spray range of the air 52 can be controlled based on the structure of the nozzle 51 for each of the primary to tertiary systems 20a to 20c.

[0077] In a further alternative embodiment, the injection settings set for each of the primary to tertiary systems 20a to 20c may be a combination of any two or more of the above-mentioned settings of the injection pressure based on the control of the controller 27, the settings of the injection period based on the control of the controller 27, the settings of the injection coverage range based on the control of the controller 27, and the structure of the nozzle 51.

[0078] Fig. 9 is a block diagram showing an example of the flow of objects 90 to be sorted in a sorter 110 according to the second embodiment when the rate of defective products is low (for example, 10% or less). The example of Fig. 9 differs from the example of Fig. 1 in that the sorter 110 has a primary system 20a and a secondary system 20b, but does not have a tertiary system 20c, and in that objects 90 to be sorted that are discharged as defective products from the secondary system 20b are discharged into a defective product container 29. In other respects, the example of Fig. 9 is the same as the example of Fig. 1.

[0079] 9, similarly to the example of Fig. 1, the injection settings may be set so that the injection range of the air 52 in the primary system 20a is wider than the injection range of the air 52 in the secondary system 20b. Even in this way, the effect (improvement in the purity and yield of non-defective products) obtained due to the difference in the injection range of the air 52 between the primary system 20a and the secondary system 20b, as described in the example of Fig. 1, can be obtained.

[0080] 10 is a block diagram showing an example of the flow of objects 90 to be sorted in the sorter 110 when the rate of defective products is moderate (for example, 60% or less). This flow of objects 90 to be sorted is achieved by the controller 27 sending control signals to the switching valves 21-24, and in response to this, the discharge destinations of the objects 90 to be sorted discharged to the first discharge conduit 76 and the objects 90 to be sorted discharged to the second discharge conduit 77 are switched. The example in FIG. 10 differs from the example in that the sorter 110 is equipped with a primary system 20a and a secondary system 20b, but does not have a tertiary system 20c, and Primary system 20a 5 in that the objects to be sorted 90 that are discharged as defective products from the container 21 are discharged into a defective product container 29. In other respects, the example of FIG. 10 is the same as the example of FIG.

[0081] 10, similarly to the example of Fig. 5, the injection settings may be set so that the injection range of the air 52 in the secondary system 20b is wider than the injection range of the air 52 in the primary system 20a. Even in this case, the effect (improvement in the purity and yield of non-defective products) obtained due to the difference in the injection range of the air 52 between the primary system 20a and the secondary system 20b, as described in the example of Fig. 5, can be obtained.

[0082] FIG. 11 is a block diagram showing an example of the flow of objects 90 in the sorter 110 when the rate of defective products is high (e.g., 60% or more). This flow of objects 90 is achieved by the controller 27 sending control signals to the switching valves 21-24, which in turn switch the discharge destinations of the objects 90 discharged into the first discharge conduit 76 and the second discharge conduit 77. The example of FIG. 11 differs from the example of FIG. 6 in that the sorter 110 includes a primary system 20a and a secondary system 20b, but does not include a tertiary system 20c, and in that objects 90 discharged as non-defective products from the secondary system 20b are discharged into a non-defective product hopper 28. In other respects, the example of FIG. 11 is the same as the example of FIG. 6.

[0083] 11, similarly to the example of Fig. 6, the injection settings may be set so that the injection range of the air 52 in the secondary system 20b is wider than the injection range of the air 52 in the primary system 20a. Even in this case, the effect (improvement in the purity and yield of non-defective products) obtained due to the difference in the injection range of the air 52 between the primary system 20a and the secondary system 20b, as described in the example of Fig. 6, can be obtained.

[0084] Although the embodiments have been described above, the above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention may be modified or improved without departing from the spirit thereof, and the present invention includes equivalents thereof. Furthermore, any combination or omission of the components described in the claims and specification is possible within the scope of solving at least part of the above-described problems or achieving at least part of the effects.

[0085] For example, the number of sorting systems of the sorter is not limited to three as exemplified in the first embodiment or two as exemplified in the second embodiment, but may be four or more. In this case, different injection settings may be set between at least two of the four or more sorting systems.

[0086] Furthermore, the injection settings for each sorting system are not limited to the above example, and can be set arbitrarily depending on the balance between the required sorting accuracy and yield and the properties (e.g., specific gravity) of the objects to be sorted 90. For example, when using a sorting machine with three sorting systems to process objects to be sorted 90 containing foreign matter with a relatively high specific gravity (e.g., stones), the injection settings may be set so that the sorting machine has a sorting system with a first injection range, a sorting system with a second injection range narrower than the first range, and a sorting system with a third injection range narrower than the second range. In this case, the sorting system with a second injection range can more reliably remove foreign matter with a relatively high specific gravity than the sorting system with a third injection range.

[0087] Furthermore, the fluid sprayed onto the objects 90 for sorting is not limited to the air 52 exemplified in the above embodiment, but may be any fluid. For example, the fluid may be a gas other than air (for example, an inert gas such as nitrogen) or a liquid.

[0088] Furthermore, sorting by the sorting machine 10 is not limited to sorting the objects 90 into non-defective and defective products, but may also sort the objects 90 into first-quality objects having a first quality and second-quality objects having a second quality different from the first quality. For example, the objects 90 may be sorted into non-defective products of relatively high quality and non-defective products of relatively low quality. Alternatively, the objects 90 may be sorted into defective products of relatively high quality and defective products of relatively low quality. [Explanation of symbols]

[0089] 10,110...Optical sorting machine 20a...First selection line 20b...Secondary selection line 20c...Third selection system 21~26...Switching valve 27...Controller 28...Good product hopper 29...defective container 31,32...light source 33,34...light 35,36...Light emitting element 41,42...Optical sensors 43, 44...Photodetector 50...Sorting device 51, 51a, 51b, 51c...Nozzles 52...Air 53...Aperture 54, 54a, 54b, 54c...Air tank 55, 55a, 55b, 55c...Pressure regulating valve 56, 56a, 56b, 56c...Manifold 57...First pipe 58...Second piping 59...Third Pipe 71...Storage tank 72...Feeder 73...Shoot 73a...Primary lineage area 73b...Secondary system area 73c...Tertiary system area 74,75...bulkhead 76...First discharge trough 77...Second discharge trough 80...Images 81, 82, 84... pixels 90, 91, 92...Items to be sorted 95...Transportation route 531,532,533...Aperture 591,592,593... Valves 831,832,833,861,862,863...Injection range 841,842...overlap area D1...transfer direction D2...Cross direction

Claims

1. An optical sorting machine, a light source configured to irradiate the objects to be sorted with light during transportation; an optical sensor configured to detect light emitted from the light source and associated with the objects to be sorted; a sorting device having a nozzle for ejecting a fluid, the sorting device being configured to eject the fluid from the nozzle onto a specific object to be sorted, the specific object being determined based on a signal acquired by the optical sensor, thereby sorting the object; Equipped with the optical sorting machine includes N-th (N is an integer of 2 or more) sorting systems each configured to perform optical sorting using the light source, the optical sensor, and the sorting device; At least two of the N-th sorting systems are configured to be operable such that settings that affect the spray range of the fluid by the sorting device against the specific object to be sorted are different from each other; (i) the setting that affects the spray range of the fluid includes setting the spray pressure of the fluid; (ii) the setting that affects the fluid ejection range includes setting the fluid ejection period; (iii) the settings that affect the fluid jetting range include the structure of the nozzle; Satisfy at least one of the following: Optical sorting machine.

2. An optical sorting machine, a light source configured to irradiate the objects to be sorted with light during transportation; an optical sensor configured to detect light emitted from the light source and associated with the objects to be sorted; a sorting device having a nozzle for ejecting a fluid, the sorting device being configured to eject the fluid from the nozzle onto a specific object to be sorted, the specific object being determined based on a signal acquired by the optical sensor, thereby sorting the object; Equipped with the optical sorting machine includes N-th (N is an integer of 2 or more) sorting systems each configured to perform optical sorting using the light source, the optical sensor, and the sorting device; At least two of the N-th sorting systems are configured to be operable such that settings that affect the spray range of the fluid by the sorting device against the specific object to be sorted are different from each other; The setting that affects the injection range of the fluid includes setting an injection pressure of the fluid, The sorting device includes a pressure regulating valve configured to regulate the pressure of the fluid supplied to the nozzle, for each of the N sorting systems. Optical sorting machine.

3. An optical sorting machine, a light source configured to irradiate the objects to be sorted with light during transportation; an optical sensor configured to detect light emitted from the light source and associated with the objects to be sorted; a sorting device having a nozzle for ejecting a fluid, the sorting device being configured to eject the fluid from the nozzle onto a specific object to be sorted, the specific object being determined based on a signal acquired by the optical sensor, thereby sorting the object; Equipped with the optical sorting machine includes N-th (N is an integer of 2 or more) sorting systems each configured to perform optical sorting using the light source, the optical sensor, and the sorting device; At least two of the N-th sorting systems are configured to be operable such that settings that affect the spray range of the fluid by the sorting device against the specific object to be sorted are different from each other; The optical sorting machine includes at least a first sorting system and a second sorting system as the N-th sorting system, the optical sorting machine is configured to sort the objects to be sorted into first-quality objects having a first quality and second-quality objects having a second quality different from the first quality; The optical sorter further comprises: In the primary sorting system, the fluid is sprayed onto the objects to be sorted that have been determined to be the second-quality objects based on the signal, so that the objects are sorted into a first group of objects to which the fluid has not been sprayed and a second group of objects to which the fluid has been sprayed, and the first group of objects to be sorted is discharged from the primary sorting system as the first-quality objects, and the second group of objects to be sorted is input into the secondary sorting system. In the secondary sorting system, the fluid is sprayed onto the objects determined to be the second quality objects based on the signal, so that the second group of objects is sorted into a third group of objects that have not been sprayed with the fluid and a fourth group of objects that have been sprayed with the fluid, and the third group of objects is re-introduced into the primary sorting system. It is configured as follows: A setting that influences the spray range of the fluid in the first sorting system is set so that the spray range of the fluid in the first sorting system is wider than the spray range of the fluid in the second sorting system, or the frequency at which the spray range becomes wider increases. Optical sorting machine.

4. 4. The optical sorting machine according to claim 3, The optical sorting machine further includes a third sorting system as the Nth sorting system, The optical sorting machine comprises: The fourth group of objects to be sorted is input into the third sorting system, In the tertiary sorting system, the fluid is sprayed onto the objects determined to be the first quality objects based on the signal, so that the fourth group of objects is sorted into a fifth group of objects that have not been sprayed with the fluid and a sixth group of objects that have been sprayed with the fluid, and the fifth group of objects is discharged from the tertiary sorting system as the second quality objects, and the sixth group of objects is re-introduced into the secondary sorting system. It is configured as follows: A setting that influences the spray range of the fluid in the first sorting system is set so that the spray range of the fluid in the first sorting system is wider than the spray ranges of the fluid in the second sorting system and the third sorting system, or the frequency at which the spray range becomes wider increases. Optical sorting machine.

5. 4. The optical sorting machine according to claim 3, The optical sorting machine is configured so that the fourth group of objects to be sorted is discharged as the second quality objects from the secondary sorting system. Optical sorting machine.

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