JP6478474B2 - Granule inspection device - Google Patents

Description

  The present invention relates to a granular material inspection apparatus that detects light from a granular material that is an object to be inspected and that passes through a passage in a predetermined passing direction and evaluates the granular material based on the detection result. .

  In Patent Document 1, light sources are arranged on both sides of a pellet passage that is a granular material, light from the pellets illuminated by the light source is detected by a light receiving means (line sensor), and based on the detected light amount. A granular material inspection apparatus for evaluating pellets is disclosed. In this granular material inspection apparatus, each light source includes a linear light source (fluorescent lamp) as a component, a diffusion transmission plate that diffuses light from the light source, and a transmission window adjacent to the pellet. The central optical axis and the optical axes of the line sensors on both sides (front and rear sides) are all set to intersect at one point (actually a straight line because it is a line light source) when viewed from the transverse direction of the passage path. In such a configuration, the components of the light source on the other side are included in the background of the pellet reflected in the line sensor on the one side. Therefore, if there is unevenness in brightness between the component and other background areas, for example, if there is a shadow part or overexposed part, the unevenness in brightness may be reflected on the pellet, and light from the pellet will be reflected. This will adversely affect the light quantity evaluation of the line sensor. In particular, in the case where a slit for light receiving means is formed in the illumination light path by the light source, since the inside of the slit becomes a dark part, the pellet is received by the line sensor on the side facing the light source. Shadows due to dark areas appear and cause evaluation errors.

  In the passage of beans that are granular bodies, a first detection position and a second detection position are provided at intervals in the passage direction, and quality evaluation by independent first and second optical detection devices is performed in Patent Literature. 2. The first and second optical detection devices include an illumination lamp and a photodetector that are independent from each other, and an optical influence between them is avoided. However, in this inspection apparatus, the first optical detection device is configured to detect diffuse / transmitted light from the beans, and the second optical detection device is configured to detect reflected light from the beans. Both use illumination light that is irradiated only from one side. In addition, the types of defects to be detected are different between the first and second optical detection devices. That is, in this inspection apparatus, only two optical detection apparatuses are independently arranged in order to detect different defects. In addition, since the beans that are the object to be inspected are irradiated with illumination light from only one direction, a shadow is generated on the surface of the object to be inspected that faces the light detection sensor. May give.

JP 2001-264256 A JP-A-7-96253

  In view of the above circumstances, there is a demand for a granular material inspection apparatus having a configuration of an illumination system and a light receiving system that can obtain a more appropriate light detection result.

The granular material inspection apparatus according to the present invention includes a passage that allows a granular material that is an inspection object to pass in a predetermined passage direction, a first inspection region that is defined in the passage route, and the first inspection region that is defined in the passage route. A first inspection region having a second inspection region defined with a gap in the passage direction and an optical axis extending in a transverse direction with respect to the passage direction and optically aiming at the first inspection region A unit, a first front illumination unit that illuminates the first inspection area with the back facing the first light reception unit, and a first back illumination unit that illuminates the first inspection area facing the first light reception unit; The optical axis extending in a direction transverse to the passage direction, and optically aiming the second inspection area from the opposite side of the first light receiving unit with respect to the passage path. Two light-receiving units, a second front illumination unit that illuminates the second inspection area with its back to the second light-receiving unit, and a second backlight that illuminates the second inspection area facing the second light-receiving unit A unit and an evaluation unit that evaluates the state of the object to be inspected based on signals from the first light receiving unit and the second light receiving unit, and in front of the first front illumination unit, the first front surface. A curved diffusion member bulging toward the lighting unit side is provided, and a curved diffusion member bulging toward the second front lighting unit side in front of the second front lighting unit And a slit through which the optical axis of the corresponding light receiving unit passes is formed in the diffusing member, and the first back lighting unit and the second back lighting unit Karadadea is, the distance between the optical axis of the second light receiving unit and the optical axis of the first light receiving unit, the first light receiving unit and the passage path is an optical aiming point of the second light receiving unit A value obtained by dividing each of the separation distances from the center to the illumination surfaces of the first backlight unit and the second backlight unit is 1.5 or more .

In the granular material inspection apparatus having the above-described configuration, two inspection areas are set with a gap in the passage of the granular material that is the object to be inspected, and an independent optical inspection unit is allocated and arranged in each inspection area. One optical unit includes a first front illumination unit and a first back illumination unit that illuminate the granular material in the first inspection region, and a first light receiving unit that receives light from the granular material illuminated by these. ing. Since the first light receiving unit is optically aimed at the first inspection area, the granular material to be inspected can be accurately captured in the first inspection area. For example, if the first light receiving unit is a camera unit, it is possible to accurately photograph the granular material in the light illuminated by the front light and the backlight. Since the first front illumination unit is arranged to irradiate the granular material from the first light receiving unit side and the first back lighting unit is irradiated to irradiate the granular material from the opposite side, the granular material to be inspected is the first Illuminated from various angles including secondary light reflected in the inspection area and received on the light-receiving surface of the first light-receiving unit that receives light from the granular material, that is, a light-receiving image of the granular material that is the inspection object (photographing) It is unlikely that shadows or dark areas due to ambient lightness unevenness will occur in the image. Similarly, the other optical unit includes a second front illumination unit and a second back illumination unit that illuminate the granular material in the second inspection region, and a second light receiving unit that receives light from the granular material illuminated by these. Since the second light receiving unit is configured to optically aim at the second inspection area, the granular object to be inspected is light illuminated by the front light and the backlight in the second inspection area. There is a low possibility that light from the granular body located in the light enters the light-receiving surface of the second light-receiving unit, and a shadow or dark part due to uneven brightness in the light-receiving image (photographed image) occurs. In addition, since the first inspection region and the second inspection region are spaced apart from each other, the light and dark portions created by the members forming the second inspection region and the components of the optical unit for the second inspection region are the first. There is an advantage that the possibility of entering the first light receiving unit that is optically aimed at the inspection area is small. Similarly, light and dark unevenness created by the members forming the first inspection region and the components of the optical unit for the first inspection region enter the second light receiving unit that is optically aimed at the second inspection region. There is an advantage that the possibility is small. As a result, the obtained light reception information becomes high quality information as compared with the prior art, and the reliability of the evaluation is also high.
Here, the illumination light from the front illumination unit (first and second) that illuminates the front surface of the inspection object (granular body) with respect to the light receiving surface (imaging surface) of the light receiving unit has a uniform light amount distribution. Although it is preferable, if the illumination light is too diffused for uniformity, the amount of light that illuminates the object to be inspected decreases. That is, the illumination light from the front illumination unit has a contradictory problem that it is desired to give a sufficient amount of light to the inspection object while diffusing. Moreover, since the light which goes to a light reception unit from a to-be-inspected object must pass a front illumination unit, the passage route is required for a front illumination unit. However, according to the above configuration, it is possible to receive light from the inspection object in a state where illumination light having a uniform and sufficient amount of light is applied to the front surface of the inspection object, and a high-quality captured image can be obtained. Moreover, the slit provided in the diffusing member serves as a light passage path from the inspection object to the light receiving unit.
At this time, since the first inspection area and the second area are spaced apart from each other in the passage path, the slit formed in the diffusion member of the first front illumination unit becomes a dark part when viewed from the second light receiving unit. This eliminates the inconvenience of casting a shadow on the inspection object. Similarly, the inconvenience that the slit formed in the diffusion member of the second front illumination unit becomes a dark part when viewed from the first light receiving unit and casts a shadow on the inspection object is also eliminated.
In photographing illumination for an object to be inspected, not only illumination from the front but also illumination from the background is important. However, if a reflex plate that simply reflects light is arranged behind the object to be inspected as in normal product photography, the surrounding dark area may be reflected from the reflex plate, resulting in undesirable back lighting. . In addition, since the backlight is backlit for the light receiving unit, the uniformity of the light amount distribution is important. According to the above configuration, since the surface light emitter is used as the back illumination, the uniformity of the light amount distribution and a stable light amount can be obtained.

  Furthermore, with regard to the arrangement of the first light receiving unit and the second light receiving unit, in one of the preferred embodiments of the present invention, the second light receiving unit is located on the passage path from the opposite side to the first light receiving unit. An optical aim is aligned with the second inspection region. In this configuration, since one optical unit and the other optical unit are arranged on the opposite sides with respect to the passage path, the granular material can be inspected from one surface by one optical unit, and the other With this optical unit, the granular material can be inspected from the other surface.

In one preferred embodiment of the present invention, the first backlight unit and the second backlight unit are configured as a surface light emitter using a light guide member. Further, in one preferred embodiment, a light transmission protection plate is disposed between the light guide member and the passage path, and an antireflection film is formed on a surface of the light transmission protection plate facing the passage path. ing. The light transmission protection plate prevents the light guide member made of resin such as acrylic from being adversely affected by the inspection object.
Further, the antireflection film suppresses that the reflected light reflected locally on the surface of the light transmission protection plate enters the light receiving unit and adversely affects the detection result.

  The light intensity balance between the front illumination and the back illumination has a large effect on the light detection result (light-receiving value or photographed image) from the object to be inspected, so fine adjustment is required depending on the type of object to be inspected and the type of defect to be inspected. Is preferred. This is because an optimum light detection result is obtained by optimal adjustment of the type of inspection object and the type of defect to be inspected. In addition, when uneven illumination occurs due to the geometric conditions of the constituent members constituting each inspection region, it may be solved by changing the light quantity balance between the front illumination and the back illumination. Therefore, in one of the preferred embodiments of the present invention, the light amounts of the first front lighting unit, the first back lighting unit, the second front lighting unit, and the second back lighting unit can be adjusted, respectively. It is configured.

  Furthermore, as described above, a curved diffusing member is used in front illumination, and a surface light emitter is used for back illumination, so that the amount of light from the back of the object to be inspected increases, and the front of the object to be inspected has various directions. By irradiating with the light from, the occurrence of overexposure due to specular reflection at the flat inspection object is also suppressed.

  Since the first inspection area and the second inspection area are spaced from each other in the passage path, an optical unit for the first inspection area (first optical unit) and an optical unit for the second inspection area ( Since there is a low possibility of interference with the second optical unit), there is a high degree of freedom in their arrangement. For example, when the passage path is linear, the structurally simple ones are the optical axis of the first optical unit (the optical axis serving as the illumination center and the light receiving (camera) optical axis) and the second optical unit. In this arrangement, the optical axis is orthogonal to the passage path. Accordingly, in one preferred embodiment of the present invention, the optical axis of the first light receiving unit, the optical axis serving as the illumination center of the first front illumination unit, and the illumination center of the first back illumination unit are provided. The optical axis is orthogonal to the passage path and coincides with the passage path, and the optical axis of the second light receiving unit, the optical axis serving as the illumination center of the second front illumination unit, and the second back surface An optical axis serving as an illumination center of the illumination unit is configured to be orthogonal to the passage route and coincide with the passage route.

  At this time, the optical axis of the first optical unit and the optical axis of the second optical unit need to be separated to the extent that they are not affected by the dark portions such as the above-described slits. Further, it is preferable that the background illumination unit is as close to the passage route as possible so that surrounding dark portions and highlight portions are not reflected. In this regard, according to the knowledge of the present inventor, the distance between the optical axis of the first optical unit and the optical axis of the second optical unit is P, and the distance from the center of the passage path to the illumination surface of the rear illumination unit When D is D, it has become clear that P / D is preferably 1.5 or more. Further, when it is desired to suppress the size in the transverse direction of the passage path as a whole apparatus, the optical axis of the first optical unit and the optical axis of the second optical unit may be inclined with respect to the passage path.

It is a typical side view for demonstrating the fundamental structure of this invention. It is a typical top view for demonstrating the fundamental structure of this invention. It is a typical side view which shows the modification of the basic composition of this invention shown in FIG. It is a typical side view which shows another modification of the basic composition of this invention shown in FIG. It is explanatory drawing for demonstrating the optical test | inspection by this invention. It is explanatory drawing for demonstrating the determination criterion of normal and abnormality in the optical test | inspection by this invention. It is the whole resin pellet test | inspection apparatus which is one of the concrete embodiment of the granular material test | inspection apparatus by this invention. It is a vertical side view of the resin pellet inspection apparatus in the 1st inspection field and the 2nd inspection field. It is a perspective view which shows a 1st optical unit and a 2nd optical unit. It is a cross-sectional perspective view which shows the optical axis of a 1st optical unit and a 2nd optical unit. It is a functional block diagram of a control system centering on an inspection controller.

Before describing a specific embodiment of the granular material inspection apparatus according to the present invention, a basic configuration characterizing the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic side view for explaining a basic configuration of a granular material inspection apparatus, and FIG. 2 is a schematic plan view.
In this granular material inspection apparatus, the granular material which is an object to be inspected falling along a passing path G extending linearly in the up-down direction from above is divided into two locations, a first inspection area TA1 and a second inspection area TA2. Perform an optical inspection at The first inspection area TA1 and the second inspection area TA2 are spaced apart from each other in the passage direction of the granular material. The inspection results in the first inspection area TA1 and the second inspection area TA2 are evaluated by the evaluation unit 70 of the inspection controller 7, and are classified into acceptable products and unacceptable products by the sorting mechanism SD controlled based on the evaluation results. Collected.

  The granular material inspection apparatus includes a first optical unit 1A that optically inspects the granular material in the first inspection area TA1, and a second optical unit 1B that optically inspects the granular material in the second inspection area TA2. Yes. The first optical unit 1A includes a first front illumination unit 4A, a first rear illumination unit 5A, and a first light receiving unit 6A. The second optical unit 1B includes a second front illumination unit 4B, Two back lighting units 5B and a second light receiving unit 6B are provided. The optical axis OA1 of the illumination system and the imaging (light reception) system of the first optical unit 1A is common and extends in the transverse direction of the passage path G and passes through the center of the first inspection area TA1. The optical axis OA2 of the illumination system and the imaging system of the second optical unit 1B is also common and extends in the transverse direction of the passage route G and passes through the center of the second inspection area TA2. With this arrangement, the first light receiving unit 6A is optically aimed at the center of the first inspection area TA1, and the first light receiving unit 6A receives light from the granular material located in the first inspection area TA1. The first front illumination unit 4A illuminates the first inspection area TA1 with the back facing the first light receiving unit 6A. The first back lighting unit 5A faces the first light receiving unit 6A and illuminates the first inspection area TA1.

Since the first optical unit 1A and the second optical unit 1B have substantially the same structure, in the following description, when there is no need to distinguish between them, the notation of “first and second” In addition, the subscripts of the figure numbers “A and B” are removed, and the optical unit 1, the front illumination unit 4, the back illumination unit 5, and the light receiving unit 6 are simply described and described in common.
The front illumination unit 4 is a line illumination module 41 composed of an upper LED row and a lower LED row arranged above and below the optical axis OA, a curved diffusing member 42, and a light transmission protection plate. And a glass plate 44. The diffusing member 42 is disposed such that its curved surface bulges toward the line illumination module 41 side. The glass plate 44 is a boundary wall between the diffusion member 42 and the passage route G. The line illumination module 41 here is a light source in which LEDs are arranged in a straight line in one or more rows. The diffusing member 42 is a half-cracked cylinder having a curved cross section, and is arranged so that a convex surface comes to the line illumination module 41 side. A linear slit 43 through which the optical axis OA passes is formed at the center position of the diffusing member 42. The light (reflected light and transmitted light) from the granular material passes through the slit 43 and enters the light receiving unit 6. Therefore, the slit 43 has a length corresponding to the photographing width (light receiving width) of the light receiving unit 6.

  The backlight unit 5 includes four LED linear array modules 51, a light guide member 52, and a glass plate 54 as a light transmission protection plate. The light guide member 52 is an elongated rectangular resin plate having a light guide property disposed so as to face the diffusion member 42 of the front illumination unit 4, and has a light projecting surface whose rectangular surface having a large area faces the inspection area TA. It has become. The LED linear array module 51 is arranged so that LED light is incident on almost the entire area of the four side surfaces corresponding to the four sides of the light guide member 52. A glass plate 54 is attached to the light projecting surface of the light guide member 52. The longitudinal length of the light guide member 52 (the length in the particle passing direction) is longer than that of the diffusion member 42 and has a length 1.5 to 2 times longer. The lateral length of the light guide member 52 exceeds the length of the slit 43 and can uniformly illuminate a range that greatly exceeds the imaging range of the light receiving unit 6. An antireflection film 54 a is formed on the surface of the glass plate 54 that faces the passage route G.

  The light receiving unit 6 is a well-known industrial photographic camera, and includes a lens unit 61 and a line sensor unit 62 composed of a CCD or a CMOS. Of course, a line-shaped light receiving element of the rectangular sensors may be used as a line sensor by using a general photographing camera. Various filters can be attached to the front surface of the lens unit 61.

  In the above description of the basic configuration of the present invention, the optical axis OA1 of the first optical unit 1A and the optical axis OA2 of the second optical unit 1B intersect at right angles to the passage path G. As shown, it may be configured to intersect at an inclination angle θ. Accordingly, the space occupied by the first optical unit 1A and the second optical unit 1B in the transverse direction of the passage route G is reduced. At that time, the illumination optical axis of the back illumination unit 5 may remain orthogonal to the passage path G, but the illumination optical axis of the front illumination unit 4 is the optical axis OA1 of the optical unit 1, that is, the optical axis of the light receiving unit 6. It is preferable to match. Of course, the illumination optical axis of the front illumination unit 4 may remain orthogonal to the passage path G as long as the light passage path to the light receiving unit 6 can be secured. Of course, a pair of mirrors 60 may be provided between the optical axes OA1 and OA2, and the optical axes OA1 and OA2 may be bent.

  In the description of the basic configuration of the present invention described above, two inspection areas TA1 and TA2 are provided to capture (photograph) the light from one side surface (front surface) and the other side surface (back surface). Although provided, in order to further improve the inspection quality, the inspection area may be further increased. For example, in FIG. 4, four inspection areas TA1, TA2, TA3, and TA4 are provided, and the optical unit 1 is provided in each.

  Next, the principle of the optical inspection method employed in the granular material inspection apparatus according to the present invention will be described with reference to FIGS. As can be understood from the relationship between the line sensor unit 62 and the granular material shown in FIG. 5, each light receiving element of the line sensor unit 62 is a scanning line extending in the transverse direction with respect to the passing direction of the granular material. Light is detected in the micro compartment p. The light reception signals scanned at a predetermined sampling frequency and generated by the respective light receiving elements of the line sensor unit 62 are sent to the inspection controller 7, subjected to necessary preprocessing, and then evaluated by the evaluation unit 70. An example of this evaluation method is a method of comparing the amount of received light (signal amplitude value) with a threshold value. This threshold value is an upper limit threshold value THH and a lower limit threshold value THL that are set based on the amount of received light obtained in a normal granular material. An appropriate light amount range ΔE is set between the upper threshold THH and the lower threshold THL, and if the measured received light amount enters the appropriate light amount range ΔE, it is considered normal. Considered abnormal. Here, the evaluation of the granular material is not performed with the amount of light received in units of micro-partitions p, but evaluation is performed using a collection of micro-partitions p of a predetermined length as an evaluation unit. Such an evaluation unit is set according to the type and quality specification of the granular material to be inspected.

  For example, when there is an abnormal part having a concentration different from that of a normal object at a part of the outer periphery of the granular material, the amount of light received by the line sensor unit 62 for the evaluation unit that receives the reflected light from the abnormal part is If the appropriate light amount range ΔE is deviated, it is regarded as detecting the presence of an abnormal object. FIG. 6 schematically shows the output of the line sensor unit 62 when an abnormal object is detected. In FIG. 6, e0 is an output voltage level with respect to standard reflected light from a normal granular material. E1 and e2 at which the output voltage of the light receiving element is lower than the lower limit threshold THL indicate an abnormal body having a reflectance lower than that of a normal granular body. E3, which is an output voltage level at which the output voltage of the light receiving element is larger than the upper threshold THH, indicates an abnormal body (for example, a white granular body having a high brightness) having a higher reflectance than that of a normal granular body.

  Next, a specific embodiment of the present invention will be described with reference to FIGS. The granular material inspection apparatus according to this embodiment is an apparatus for inspecting translucent resin pellets. A large number of resin pellets are sent to an inspection area as inspection objects, and are normal (acceptable) or abnormal (invalid) A discriminating process for discriminating whether the product is an acceptable product) using an optical inspection, and a separating process between a normal product and an abnormal product.

  As shown in FIG. 7, a shooter 11 having an inclined posture is provided to guide the flow down so that the pellets pass through the first inspection region TA1 and the second inspection region TA2 spaced apart in the vertical direction in a single layer and in a wide state. ing. The pellets are vibrated and conveyed by a vibration feeder 13 from a storage hopper 12 provided on the upper side of the shooter 11 and put into the shooter 11. The charged pellets are discharged before the first inspection area TA1 while flowing down the upper surface of the shooter 11, pass through the first inspection area TA1 and the second inspection area TA2, and sorted into normal and abnormal substances. The

  As shown in FIG. 7, the storage hopper 12 to which pellets are supplied and stored from the outside is formed in a tapered shape toward the lower end side in a side view, and the vibration feeder 13 is discharged from the lower portion of the storage hopper 12. The receiving mounting part 14 which receives a pellet and the vibration generator 13A which gives a vibration to the receiving mounting part 14 are provided. By applying vibration to the receiving placement portion 14 by the vibration generator 13 </ b> A, pellets spread from one end of the receiving placement portion 14 substantially in a single layer state over the entire width in the width direction of the shooter 11. Supplied on top. The shuter 11 is configured as a flat plate-like shooter 11 that forms a flat flow guide surface over the entire width in the width direction, and forms the first half path of the pellet passage path G.

  As shown in an enlarged view in FIG. 8, the pellets guided by the shooter 11 are inspected while they are ejected from the shooter 11. Therefore, in this pop-out path, which is the inspection path of the passage path G, the first inspection area TA1 and the second inspection area TA2 are inspected for the pellets that are flowing down and spaced apart from each other in the flow-down direction. The normal pellets that have passed through the first inspection area TA1 and the second inspection area TA2 are dropped and recovered as they are in the normal object recovery unit 16 on the lower side, and the abnormal substances are sprayed by the air spraying device 15 as the sorting mechanism SD. By being changed in direction by the action, it is sorted and collected by the abnormal matter collecting unit 17.

  In this embodiment, the shooter 11 is inclined at an inclination angle α of about 15 ° to 20 ° so that the pellets flow smoothly along the flow guide surface, and the passage path G is also at the same inclination angle α. It is inclined.

  Also in this embodiment, the first optical unit 1A for inspecting the pellet at a position corresponding to the first inspection area TA1 is provided, and the second optical for inspecting the pellet at a position corresponding to the second inspection area TA2. A unit 1B is provided. Also in this embodiment, the first optical unit 1A and the second optical unit 1B have the basic structure described with reference to FIGS. In the first optical unit 1A, the first front illumination unit 4A and the first light receiving unit 6A are arranged on the right side across the passage path G in the side views shown in FIGS. The first backlight unit 5A is arranged on the left side of G, that is, on the front side of the apparatus. Since the optical axis OA1 of the first optical unit 1A is orthogonal to the passage path G, as a result, the optical axis OA1 of the first optical unit 1A is inclined at an inclination angle α with respect to the horizontal line. . Further, the second optical unit 1B has the second front illumination unit 4B and the second light receiving unit 6B on the left side across the passage path G in the side view of FIG. The 2nd back lighting unit 5B is arrange | positioned. Since the optical axis OA2 of the second optical unit 2A is also orthogonal to the passage path G, as a result, the optical axis OA2 of the second optical unit 1B is also inclined at an inclination angle α with respect to the horizontal line. .

  As shown in FIGS. 8 to 10, the first optical unit 1 </ b> A and the second optical unit 1 </ b> B are housed in a box-shaped housing case 18 so as to be surrounded almost entirely, but have a flat cross section. In order to pass through the passage route G having a slender opening, elongated openings are formed in the top plate region and the bottom plate region. Further, in order to allow good access to the first inspection area TA1 and the second inspection area TA2 in the passage route G, openings 18A are formed in the left and right side plate areas, and the first inspection area TA1 and the second inspection area TA2 are formed. It is easy to perform maintenance and inspection.

  The first optical unit 1A and the second optical unit 1B are displaced with respect to the passage route G, and are attached with a positional relationship facing diagonally with respect to the passage route G, but the structure is substantially the same. Here, only the first optical unit 1A will be described, and the second optical unit 1B will be omitted.

  Although only schematically shown in FIGS. 8 and 10, the first front illumination unit 4 </ b> A includes, as the line illumination module 41, two LED linear arrays sandwiching the optical axis OA <b> 1 that is also the illumination center line. Modules 41a and 41b are arranged and curved and plate-like diffusing members bulge toward the two LED linear array modules 41a and 41b so as to cover the irradiation side of the two LED linear array modules 41a and 41b. 42 is arranged. Each of the LED linear array modules 41a and 41b has a form in which LED elements are arranged in a length corresponding to the width of the passage path G in one or more rows. The LED linear array modules 41a and 41b and the diffusing member 42 are fixed to the mounting frame 18a. At this time, the diffusing member 42 has a posture in which the curved surface side that is convex faces the LED linear array modules 41a and 41b, and the optical axis OA1 that is also the illumination center line passes through the top of the diffusing member 42. Yes. A glass plate 44 is fitted on the concave curved surface side of the diffusing member 42, that is, on the first inspection area TA1 side in order to prevent the pellets from entering.

  The first light receiving unit 6 </ b> A is configured by a photographing camera, and includes a lens barrel 63 having a lens unit 61 and a sensor pack 64 having a line sensor unit 62. A filter 66 is disposed immediately in front of the lens barrel 63. The filter 66 is sandwiched and supported by a sandwiching frame body 67 a attached to a filter bracket 67 fixed to the storage case 18. Since the holding frame body 67a fastens and fixes the filter 66 with screws, it is more resistant to temperature load than those that are joined with an adhesive. The optical axis OA1 of the first light receiving unit 6A is refracted by a pair of elongated mirrors 60. The mirror 60 is fixed to the camera holder 18b for fixing the camera using a bracket piece 60a.

The optical axis OA1 of the first light receiving unit 6A passes between the upper and lower LED linear array modules 41a and 41b of the first front illumination unit 4A, and further, a slit 43 and a glass plate 44 formed on the top of the diffusing member 42. To reach the first inspection area TA1. The slit 43 is fitted with a light transmitting body 46 in which a divided processing film 46a is formed on the surface on the passing path G side. The light transmitting body 46 is an organic glass such as plate glass or acrylic. The divided processing film 46a is formed by plating or vapor-depositing tin or silver on the side surface of the organic glass, and incident light incident on the divided processing film 46a in the direction toward the first inspection area TA1 is converted into reflected light and transmitted light. A division process for dividing is performed. That is, when light passes through the light transmitting body 46, the divided processing film 46a performs split processing on transmitted light reaching the first inspection area TA1 and reflected light not reaching the first inspection area TA1. Thereby, the light reaching the first inspection area TA1 from the first light receiving unit 6A side becomes weak, and the shadow from the first light receiving unit 6A side is not easily reflected on the pellet.
Further, an AR coat as an antireflection film 46b is formed on the surface of the light transmitting body 46 on the first light receiving unit 6A side. Thereby, the reflected light which occurs in the state which goes to the 1st light reception unit 6A in the light transmissive body 46 can be suppressed weakly.

  The first backlight unit 5A uses a surface light emitting unit 53, the surface light emitting unit itself is well known, and is not limited to a specific form in the present invention. In this embodiment, a surface emitting unit 53 in which an LED linear array module 51 is attached to each of four side surfaces of a plate-like light guide member 52 is used. A glass plate 54 as a light transmission protection plate is disposed on the light projecting surface side of the light guide member 52. An antireflection film 54 a is formed on the surface of the glass plate 54 facing the passage route G. The surface emitting unit 53 and the glass plate 54 are fixed to the storage case 18 by a bracket 55. The length of the surface light emitting unit 53 with respect to the flow direction of the pellets in the passage route G is about 1.5 times the length of the diffusion member 42 functioning as the light emitting plate of the first front lighting unit 4A. A uniform and rich amount of light is given to the subject pellet as a backlight.

  With reference to FIG. 8, a suitable positional relationship in the passage route G between the first optical unit 1A and the second optical unit 1B will be described. As shown in FIG. 8, the distance between the optical axis of the first optical unit 1A and the optical axis of the second optical unit 1B in the passage path G is P, and the first optical unit 1A and the second optical unit 1B are P. Let D be the distance from the center of the passage path G, which is the optical sighting point, to the surface of the glass plate 54 that is the illumination surface of the first and second backlight units 5A and 5B. Here, it is clear from experimental results by the present inventor that a high-quality light reception result can be obtained if P / D is 1.5 or more.

  The LED elements used in the four LED linear array modules 51 of the first back lighting unit 5A and the two LED linear array modules 41a and 41b of the first front lighting unit 4A are white LED light emitting elements, and are white. A condensing part for condensing light emitted from the LED light emitting element and a diffusing part for diffusing the light are also provided. However, since the structure is well known, detailed description thereof is omitted here.

  As shown in FIG. 11, the light amounts of the four LED linear array modules 51 and the two LED linear array modules (line illumination modules) 41 (41 a, 41 b) can be adjusted by a control signal from the inspection controller 7. For this reason, the first front lighting unit 4A and the first front lighting unit 4A are connected to the inspection controller 7 via the front light quantity adjustment circuit 71, and the first back lighting unit 5A and the second back lighting unit 5B are The back light amount adjustment circuit 72 is connected to the inspection controller 7. An operation panel 80 (see FIG. 7) incorporating a touch panel is also connected to the inspection controller 7, and a manual operation signal for light amount adjustment is input to the inspection controller 7 via the operation panel 80. The inspection controller 7 outputs a control signal to the front light amount adjustment circuit 71 or the rear light amount adjustment circuit 72 based on the input manual operation signal. Based on the received control signal, the front light amount adjustment circuit 71 individually controls and drives the LED linear array modules 41a and 41b of the first front illumination unit 4A and the second front illumination unit 4B to adjust the light amount. Similarly, the back surface light amount adjustment circuit 72 individually drives and controls each LED linear array module 51 of the first back light unit 5A and the second back light unit 5B based on the received control signal, and adjusts the light amount thereof. .

  In adjusting the amount of illumination light, basically, a reference pellet having uniform light reflection characteristics and light transmission characteristics is used in the first inspection area TA1 and the second inspection area TA2, and the line sensor section 62 of the first light receiving unit 6A. And the line sensor unit 62 of the second light receiving unit 6B are adjusted in light quantity so as to output the same detection value. Since the detection signals from the line sensor unit 62 and the line sensor unit 62 are also input to the inspection controller 7, it is possible to build an automatic light amount adjustment program in the inspection controller 7 and automate the adjustment of the illumination light amount.

  The air spraying device 15 disposed below the second inspection area TA2 has an injection nozzle 15b that opens to the passage route G (see FIGS. 8 and 10). The inspection controller 7 outputs a drive signal to the electromagnetic valve 15a that turns on and off the air supply to the injection nozzle 15b. That is, in the air blowing device 15, pellets determined as rejected pellets (for example, pellets burned and colored in the resin processing process, pellets with different colors, etc.) pass in front of the injection nozzle 15 b. Sometimes air is blown from the injection nozzle 15 b to deflect the pellet toward the abnormal matter collecting unit 17.

  In the passage area G, a boundary area between the second inspection area TA2 and the air blowing device 15 is provided with an inclined bowl-shaped reflector 19 (see FIG. 8) extending from both sides toward the center of the passage path G. Yes. This reflector 19 has two functions. One of them is that light that attempts to escape downward from the first inspection area TA1 and the second inspection area TA2, particularly from the second inspection area TA2, is reflected on the upper surface and returned to the second inspection area TA2. is there. For this reason, it is preferable to apply a white ceramic coat to the upper surface of the reflection plate 19. Another one is that the flow cross-sectional area of the passage path G above the injection nozzle 15b of the air blowing device 15 is reduced, that is, the passage width in the air blowing direction is reduced, so that the pellets that are determined to be rejected are rejected. It is that air can be efficiently blown on.

Next, the whole support structure of the granular material inspection apparatus in this embodiment will be described.
As shown in FIG. 7, a bottom portion 21 provided with legs 20, a front vertical frame 22 erected from the bottom portion 21, a rear vertical frame 23, an oblique horizontal frame 24 connecting them at the left and right side portions, and the like. The gantry is configured. The vibration generator 13A of the vibration feeder 13 is supported by the horizontal frame 24 via an attachment member. On the bottom portion 21, a pressure adjusting device AH for adjusting the pressure of air from an air supply source (not shown) for supplying air to the air blowing device 15 is installed.

  A box-shaped support base 26 is erected on the rear part of the bottom 21, and a horizontal frame 25 extends obliquely upward from the front upper end of the support base 26 and is connected to the front vertical frame 22. A storage case 18 for storing the first optical unit 1A and the second optical unit 1B is supported by a horizontal frame 25. An operation panel 80 is installed on the front cover 27 that covers the upper oblique portion of the front vertical frame 22. An inspection controller 7, a power supply circuit, and the like are attached to the inner side surface of the rear cover 28. The front cover 27 and the rear cover 28 are configured to be openable and closable in the left-right direction so that the inside of the apparatus can be inspected.

[Other Embodiments] (1) In the above-described embodiment, the LED linear array module is used as the line illumination module 41 of the first front illumination unit 4A and the second front illumination unit 4B. Instead of this, another type of illumination lamp such as a fluorescent lamp may be used.
(2) In the above-described embodiment, the line illumination module 41 is arranged so that the illumination optical axis thereof is orthogonal to the passage path G. However, the illumination light axis of the curved diffusion surface 42 is curved. You may arrange | position so that it may become a vertical axis.
(3) In the above-described embodiment, the air blowing device 15 is used as the sorting mechanism SD, but the sorting may be performed by a direction switching mechanism such as a swing plate. Moreover, you may employ | adopt the structure which sorts a normal thing instead of sorting an abnormal thing by the classification mechanism SD.

  INDUSTRIAL APPLICABILITY The present invention can be used for a granular material inspection apparatus that uses a resin beret as an inspection target, and various granular materials such as wrinkles as an inspection target.

1A: 1st optical unit 1B: 2nd optical unit 13: Vibration feeder SD: Sorting mechanism 15: Air spraying device 16: Normal thing collection | recovery part 17: Abnormal thing collection | recovery part 18: Storage case 4A: 1st front illumination unit 4B: Second front illumination unit 41: line illumination module (LED linear array module)
42: diffusion member 43: slit 44: glass plate (light transmission protection plate)
46: light transmissive body 46a: division processing film 46b: antireflection film 5A: first back lighting unit 5B: second back lighting unit 51: LED linear array module 52: light guide member 53: surface light emitting unit 54: glass plate ( Light transmission protection plate)
54a: Antireflection film 6A: First light receiving unit (photographing camera)
6B: Second light receiving unit (photographing camera)
7: Inspection controller 70: Evaluation unit 71: Front light quantity adjustment circuit 72: Back light quantity adjustment circuit OA1: Optical axis OA2 of the first light receiving unit: Optical axis TA1: Second light receiving unit TA1: First inspection area TA2: Second inspection area G: Passage route

Claims (6)

A passage route through which the granular material that is the inspection object passes in a predetermined passage direction;
A first inspection region defined in the passage route;
A second inspection region defined in the passage direction with an interval in the passing direction with respect to the first inspection region;
A first light receiving unit having an optical axis extending in a transverse direction with respect to the passing direction and optically aiming at the first inspection region;
A first front illumination unit that illuminates the first inspection area with the back facing the first light receiving unit;
A first backlight unit that illuminates the first inspection area facing the first light receiving unit;
A second light receiving unit having an optical axis extending in a direction transverse to the passage direction and optically aiming at the second inspection region;
A second front illumination unit that illuminates the second inspection area with the back facing the second light receiving unit;
A second backlight unit that illuminates the second inspection area facing the second light receiving unit;
An evaluation unit that evaluates the state of the inspection object based on signals from the first light receiving unit and the second light receiving unit; and
A curved diffusing member bulging toward the first front illumination unit is provided in front of the first front illumination unit, and the second front is in front of the second front illumination unit. A curved diffusing member bulging toward the lighting unit side is provided, and the diffusing member is formed with a slit through which the optical axis of the corresponding light receiving unit passes,
The first backlight unit and the second backlight unit, Ri surface light emitters der,
The distance between the optical axis of the first light receiving unit and the optical axis of the second light receiving unit is set to the first distance from the center of the passage path which is an optical aiming point of the first light receiving unit and the second light receiving unit. A granular material inspection apparatus in which a value obtained by dividing each of the distance to the illumination surface of the backlight unit and the second backlight unit is 1.5 or more .   2. The granular material inspection apparatus according to claim 1, wherein the second light receiving unit is configured to optically aim the second inspection region from a side opposite to the first light receiving unit with respect to the passage path.   3. The granular material inspection apparatus according to claim 1, wherein each of the first backlight unit and the second backlight unit is a surface light emitter using a light guide member.   The granular material according to claim 3, wherein a light transmission protection plate is disposed between the light guide member and the passage path, and an antireflection film is formed on a surface of the light transmission protection plate facing the passage path. Physical examination device.   The granular material according to any one of claims 1 to 4, wherein light quantities of the first front lighting unit, the first back lighting unit, the second front lighting unit, and the second back lighting unit are adjustable. Inspection device. The passing path is a straight line;
The optical axis of the first light receiving unit, the optical axis serving as the illumination center of the first front illumination unit, and the optical axis serving as the illumination center of the first back illumination unit are orthogonal to the passage path and pass through the passage. And the optical axis of the second light receiving unit, the optical axis serving as the illumination center of the second front illumination unit, and the optical axis serving as the illumination center of the second backlight unit are the same. The granular material inspection apparatus according to any one of claims 1 to 5, wherein the granular material inspection apparatus is orthogonal to a path and coincides within the passage path.

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