Inspection Equipment

Abstract

To provide an inspection device with an improved accuracy.SOLUTION: Provided is an inspection device having at least two sensors 23 and at least two optical systems 22, the inspection device including: a sending device 10 capable of sending an inspection target object G to inspection routes R arranged in parallel in a reference plane PL through the inspection region IA; a first sensor 23A and a second sensor 23D as sensors 23 for detecting light from the inspection region IA; a first optical system 22A as an optical system 22 for guiding an inspection light from the inspection region IA to the first sensor 23A; a second optical system 22D as an optical system 22 for guiding an inspection light from the inspection region IA to the second sensor 23D; and a quality determination unit for determining whether the inspection target object G has a defect. The first optical system 22A and the second optical system 22D are arranged in the same side of the reference plane PL so that their respective optical axes 24 intersect with each other. The quality determination unit determines whether the inspection target object G has a defect on the basis of the sum or the product of the outputs of the first sensor 23A and the second sensors 23D.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an inspection device. [Background technology]

[0002] Patent Document 1 discloses a granular material inspection device. In this device, a transport means (vibration feeder, chute, etc.) transports an inspection object (resin pellets) so that it passes through a detection point. A light receiving means receives light from the detection point. A discrimination means discriminates whether the inspection object is normal or abnormal based on the amount of light received by the light receiving means. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-089119 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the device of Patent Document 1, the presence of an abnormality is detected based on the amount of light received by the light receiving device. Specifically, when there are black spots or contaminated spots on the surface of the pellet, the amount of light received by the unit light receiving unit that receives the reflected light from the abnormal spot falls outside the appropriate light amount range. When the amount of light received falls outside the appropriate light amount range, the object to be inspected is determined to be abnormal.

[0005] When the color of a normal portion is similar to the color of an abnormal portion, the difference in the amount of light received by the light receiving device becomes small, making it difficult to detect the abnormality (distinguish between normal and abnormal products), and reducing the inspection accuracy.

[0006] Thus, there is room for improvement in the inspection accuracy of conventional particle inspection devices.

[0007] An object of the present invention is to provide an inspection apparatus with improved inspection accuracy. [Means for solving the problem]

[0008] As a means for solving the above-mentioned problems, the inspection device of the present invention is an inspection device having two or more sensors and two or more optical systems, and is equipped with a sending device capable of sending an object to be inspected to multiple parallel inspection paths in a reference plane so as to pass through an inspection area, a first sensor and a second sensor as the sensors that detect light from the inspection area, a first optical system as the optical system that guides inspection light from the inspection area to the first sensor, a second optical system as the optical system that guides inspection light from the inspection area to the second sensor, and a pass / fail judgment unit that judges the pass / fail of the object to be inspected, wherein the first optical system and the second optical system are arranged on the same side of the reference plane with their respective optical axes intersecting, and the pass / fail judgment unit judges the pass / fail of the object to be inspected based on the sum or product of the output of the first sensor and the output of the second sensor.

[0009] The difference in brightness in the sum or product of the output of the first sensor and the output of the second sensor is greater than the difference in brightness in the output of the first sensor and the difference in brightness in the output of the second sensor. Therefore, with this configuration, even if the colors of the normal and abnormal areas are similar, it is easy to distinguish between them, and the inspection accuracy can be improved.

[0010] In the present invention, it is preferable that the output of the first sensor and the output of the second sensor are divided into a plurality of channels corresponding to a plurality of the inspection paths, and the pass / fail judgment unit calculates the sum or product of the output of the first sensor and the output of the second sensor so that outputs belonging to the channels corresponding to the same inspection path are added together.

[0011] According to this configuration, it is possible to appropriately judge the quality of the object to be inspected for each inspection path.

[0012] In the present invention, it is preferable that an illumination device is provided which irradiates light onto the inspection area, and the illumination device is configured such that light reflected from a surface of the object to be inspected is guided as the inspection light to the first sensor and the second sensor by the first optical system and the second optical system.

[0013] According to this configuration, inspection can be suitably performed when the object to be inspected is opaque or translucent.

[0014] In the present invention, it is preferable that an illumination device is provided which irradiates light onto the inspection area, and the illumination device is configured such that light transmitted through the inside of the object to be inspected is guided as the inspection light to the first sensor and the second sensor by the first optical system and the second optical system.

[0015] According to this configuration, inspection can be suitably performed when the object to be inspected is transparent or semi-transparent.

[0016] In the present invention, the inspection system further includes a third sensor and a fourth sensor that detect light from the inspection area, a third optical system that guides the inspection light from the inspection area to the third sensor, and a fourth optical system that guides the inspection light from the inspection area to the fourth sensor, wherein the third optical system and the fourth optical system are arranged on the opposite side of the reference plane to the first optical system and the second optical system, with their respective optical axes intersecting, and it is preferable that the pass / fail judgment unit judges the pass / fail of the inspected object based on the sum or product of the output of the third sensor and the output of the fourth sensor.

[0017] According to this configuration, the pass / fail judgment section judges the pass / fail of the object to be inspected based on the sum or product of the output of the third sensor and the output of the fourth sensor in addition to the sum or product of the output of the first sensor and the output of the second sensor, thereby further improving the inspection accuracy.

[0018] In the present invention, it is preferable that the optical system is configured so as to be optically aimed at approximately the same point within the inspection region.

[0019] According to this configuration, the optical system is configured so that the optical sights are aligned at approximately the same point, so that when the object passes the point, the object is simultaneously inspected by the multiple sensors in a state where the optical sights are aligned, thereby further improving the inspection accuracy of the inspection device. [Brief description of the drawings]

[0020] [Figure 1] FIG. 2 is a right side view of the particulate material inspection device. [Diagram 2] FIG. 4 is a right side view showing a main part of the inspection unit. [Diagram 3] FIG. 2 is a functional block diagram showing a control system of the granular material inspection device. [Figure 4] FIG. 1 is a diagram showing an overview of optical inspection performed by a particle inspection device. [Diagram 5] FIG. 4 is a diagram illustrating an example of an output of a sensor. [Figure 6] FIG. 13 is a diagram illustrating an example of a composite output. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] A granular material inspection device according to an embodiment of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the following embodiment, and various modifications are possible without departing from the gist of the present invention.

[0022] In each figure, the direction indicated by the symbol (FR) is the front side of the device, the direction indicated by the symbol (BK) is the rear side of the device, the direction indicated by the symbol (LH) is the left side of the device, the direction indicated by the symbol (RH) is the right side of the device, the direction indicated by the symbol (UP) is the top side, and the direction indicated by the symbol (DW) is the bottom side.

[0023] The granular material inspection device is a device that optically inspects whether an input granular material (inspection object) is normal or defective, and then sorts and discharges the normal and defective products. In this embodiment, the granular material is an opaque or translucent resin pellet. The granular material may also be grains such as brown rice or polished rice.

[0024] As shown in FIG. 1, the granular material inspection device includes a storage hopper 3, an inspection unit 4, an operation and display device 6, and a control device 7 (FIG. 3).

[0025] The storage hopper 3 stores the granular material supplied from the outside, and supplies the granular material to the inspection unit 4 .

[0026] The inspection unit 4 inspects the granular material supplied from the storage hopper 3, detects defective products, and separates the granular material into normal products and defective products and discharges them. In this embodiment, the granular material inspection device includes two inspection units 4 arranged in the left-right direction of the machine body. The number of inspection units 4 may be one, or three or more.

[0027] The operation and display device 6 is provided in the center of the front part of the device. The operation and display device 6 receives manual operations from an operator and transmits them to the control device 7. The operation and display device 6 also displays various screens under the control of the control device 7. In this embodiment, the operation and display device 6 is a liquid crystal display with a touch panel. The operation and display device 6 may be a device that combines push buttons and a liquid crystal display.

[0028] The control device 7 controls the overall operation of the particle inspection device.

[0029] [Inspection unit] An overview of the configuration and operation of the inspection unit 4 will be described with reference to Fig. 2. Hereinafter, as shown in each figure, the moving direction of the granular material G is referred to as the Z direction, the upstream side of the moving direction of the granular material G is referred to as the Z1 side, the downstream side of the moving direction of the granular material G is referred to as the Z2 side, the direction perpendicular to the Z direction in a plane perpendicular to the left-right direction of the device is referred to as the Y direction, the front side of the device in the Y direction is referred to as the Y1 side, and the rear side of the device in the Y direction is referred to as the Y2 side.

[0030] Granular material G to be inspected falls from the chute 12 to the Z2 side and is sent to an inspection area IA. The inspection area IA is illuminated by an illumination device 21. Light (inspection light) from the inspection area IA is guided to a sensor 23 by an optical system 22. The sensor 23 detects the light from the inspection area IA.

[0031] The output of the sensor 23 is transmitted to the control device 7. The control device 7 judges whether the granular material G is normal or defective based on the output of the sensor 23. The control device 7 activates the air blowing device 31 at the timing when the granular material G judged to be defective falls to the front of the air blowing device 31. The granular material G blown with air is pushed toward the Y1 side and falls into the defective product recovery section 41. The other granular materials G fall into the normal product recovery section 42.

[0032] [Configuration of the inspection unit] The inspection unit 4 includes a sending device 10 , a detecting device 20 , and a rejecting device 30 .

[0033] The sending device 10 is a device that sends out multiple granular materials G in parallel (in the left-right direction of the device, perpendicular to the paper surface of FIG. 2) to an inspection area IA. The sending device 10 is configured to be able to send the granular materials G to multiple parallel inspection paths R in a reference plane PL so as to pass through the inspection area IA. The reference plane PL is a plane that passes through the inspection area IA, and its normal extends along the Y direction.

[0034] [Delivery device] The delivery device 10 includes a vibrating feeder 11 and a chute 12 .

[0035] The vibrating feeder 11 receives the granular material G that has flowed down from the storage hopper 3 in a trough 11a, and vibrates the trough 11a to send the granular material G to a chute 12. The operation of the vibrating feeder 11 is controlled by a control device 7.

[0036] The chute 12 is a plate-like member. On the upper surface of the chute 12, multiple linear grooves are formed in a state of being aligned in parallel in the left-right direction. The width of the grooves is set to a size that allows the granular material G to flow down in a single line. The granular material G that falls from the trough 11a of the vibrating feeder 11 to the chute 12 is guided by the grooves of the chute 12, flows down in multiple parallel rows on the chute 12, and is sent to the inspection area IA. The chute 12 is arranged so that the bottom of the groove is located on the reference plane PL.

[0037] [Detection device] The detection device 20 comprises an illumination device 21, an optical system 22, and a sensor 23.

[0038] [Lighting device] The illumination device 21 includes diffuse transmission members 21A and 21B, illumination units 21C and 21D, optical axis passing portions 21E, 21F, 21G, and 21H, and background illumination units 21L, 21M, 21P, and 21Q.

[0039] The diffuse transmission members 21A and 21B are members that diffuse and transmit light from the illumination units 21C and 21D and the background illumination units 21L, 21M, 21P, and 21Q. The diffuse transmission members 21A and 21B are substantially semi-cylindrical members that extend along the left-right direction of the body and curve while protruding outward in the Y direction.

[0040] The lighting units 21C and 21D are linear light sources extending along the left-right direction of the machine body. The lighting units 21C and 21D are equipped with LED packages whose light emission intensity is controlled by the control device 7, and illuminate the inspection area IA. The lighting units 21C and 21D are disposed outside the diffuse transmitting members 21A and 21B in the Y direction. More specifically, the four lighting units 21C are disposed on the Y1 side of the diffuse transmitting member 21A. The four lighting units 21D are disposed on the Y2 side of the diffuse transmitting member 21B.

[0041] The optical axis passing portions 21E, 21F, 21G, and 21H are portions of the diffusely transmitting members 21A and 21B through which the optical axis 24 passes. The optical axis passing portions 21E, 21F, 21G, and 21H are, for example, slits extending along the left-right direction of the aircraft body. The front-upper optical axis 24A passes through the optical axis passing portion 21E. The rear-upper optical axis 24B passes through the optical axis passing portion 21F. The rear-lower optical axis 24C passes through the optical axis passing portion 21G. The front-lower optical axis 24D passes through the optical axis passing portion 21H.

[0042] The background lighting units 21L, 21M, 21P, and 21Q are linear light sources extending in the left-right direction of the machine body. The background lighting units 21L, 21M, 21P, and 21Q are equipped with LED packages whose light emission intensities are controlled by the control device 7, and illuminate the inspection area IA.

[0043] Background illumination units 21L and 21Q are disposed on the Y2 side of diffusive transmission member 21B. Background illumination units 21M and 21P are disposed on the Y1 side of diffusive transmission member 21A.

[0044] The background illumination unit 21L is disposed on the upper front optical axis 24A, and irradiates light in a direction along the upper front optical axis 24A. That is, the background illumination unit 21L supplies background light for inspection by the upper front sensor 23A.

[0045] The background illumination unit 21M is disposed on the rear-upper optical axis 24B, and emits light in a direction along the rear-upper optical axis 24B. That is, the background illumination unit 21M supplies background light for inspection by the rear-upper sensor 23B.

[0046] Background illumination unit 21P is disposed on rear-lower optical axis 24C and irradiates light in a direction along rear-lower optical axis 24C. That is, background illumination unit 21P supplies background light for inspection by rear-lower sensor 23C.

[0047] Background illumination unit 21Q is disposed on lower-front optical axis 24D and irradiates light in a direction along lower-front optical axis 24D. That is, background illumination unit 21Q supplies background light for inspection by lower-front sensor 23D.

[0048] In this embodiment, light from illumination units 21C and 21D is diffused while passing through diffuse transmission members 21A and 21B, and is illuminated into inspection area IA. When granular material G passes through inspection area IA, light from diffuse transmission members 21A and 21B is reflected by the surface of granular material G, and the light traveling along optical axis 24 is guided to optical system 22 and enters sensor 23. That is, illumination device 21 is configured such that light reflected by the surface of the granular material is guided to sensor 23 by optical system 22 as inspection light.

[0049] In the reflected light inspection of this embodiment, the background illumination units 21L, 21M, 21P, and 21Q may be turned on or off. For example, these background illumination units may be turned on to detect defective products that are darker than normal granular bodies. For example, these background illumination units may be turned off to detect defective products that are brighter than normal granular bodies.

[0050] [Optical systems and sensors] In this embodiment, the inspection unit 4 includes four optical systems 22, that is, a front-upper optical system 22A, a rear-upper optical system 22B, a rear-lower optical system 22C, and a front-lower optical system 22D.

[0051] The optical axes 24 of the optical systems 22 are referred to as follows. The optical axis of the front-upper optical system 22A is referred to as the front-upper optical axis 24A. The optical axis of the rear-upper optical system 22B is referred to as the rear-upper optical axis 24B. The optical axis of the rear-lower optical system 22C is referred to as the rear-lower optical axis 24C. The optical axis of the front-lower optical system 22D is referred to as the front-lower optical axis 24D.

[0052] In this embodiment, the inspection unit 4 includes four sensors 23, that is, a front upper sensor 23A, a rear upper sensor 23B, a rear lower sensor 23C, and a front lower sensor 23D.

[0053] Light (inspection light) emitted from the inspection area IA and traveling along the front-upper optical axis 24A is guided to the front-upper optical system 22A and enters the front-upper sensor 23A. Light (inspection light) traveling along the front-lower optical axis 24D is guided to the front-lower optical system 22D and enters the front-lower sensor 23D.

[0054] Light (inspection light) emitted from the inspection area IA and traveling along the rear-upper optical axis 24B is guided to the rear-upper optical system 22B and enters the rear-upper sensor 23B. Light (inspection light) traveling along the rear-lower optical axis 24C is guided to the rear-lower optical system 22C and enters the rear-lower sensor 23C.

[0055] In this embodiment, the optical systems 22 are configured so that the optical axes of the optical systems 22 intersect with each other. Specifically, the four optical systems 22 are configured so that the optical axes 24 intersect at approximately the same point inside the inspection area IA. Specifically, the front-upper optical system 22A, the rear-upper optical system 22B, the rear-lower optical system 22C, and the front-lower optical system 22D are configured (adjusted) so that the front-upper optical axis 24A, the rear-upper optical axis 24B, the rear-lower optical axis 24C, and the front-lower optical axis 24D intersect at one point on the inspection path R.

[0056] The upper front optical system 22A includes an upper front mirror 25A and an upper front lens device 26A. The upper front lens device 26A is adjusted so as to be focused on the inspection area IA.

[0057] The rear upper optical system 22B includes a rear upper mirror 25B and a rear upper lens device 26B. The rear upper lens device 26B is adjusted so as to be focused on the inspection area IA.

[0058] The rear-lower optical system 22C includes a rear-lower mirror 25C and a rear-lower lens device 26C. The rear-lower lens device 26C is adjusted so as to be focused on the inspection area IA.

[0059] The front-lower optical system 22D includes a front-lower mirror 25D and a front-lower lens device 26D. The front-lower lens device 26D is adjusted so as to be focused on the inspection area IA.

[0060] In this embodiment, the four optical systems 22 are configured to be optically aimed at approximately the same location within the inspection area IA. Specifically, the front-upper optical system 22A, the rear-upper optical system 22B, the rear-lower optical system 22C, and the front-lower optical system 22D are adjusted to be in focus on the inspection path R. The range in which the lens device is in focus (depth of field) varies depending on the aperture. It is preferable that the front-upper optical system 22A, the rear-upper optical system 22B, the rear-lower optical system 22C, and the front-lower optical system 22D are adjusted so that the inspection path R is included in the range in which they are in focus.

[0061] In this embodiment, the four optical systems 22 are arranged, when viewed along the Z direction (the direction of movement of the granular material G (inspection object) in the inspection area IA), with the front-upper optical system 22A and the front-lower optical system 22D (two of the optical systems 22) and the rear-upper optical system 22B and the rear-lower optical system 22C (the remaining two of the optical systems 22) sandwiching the inspection area IA therebetween.

[0062] In this embodiment, the front upper optical system 22A is disposed on the Y1 side of the reference plane PL, and the rear upper optical system 22B is disposed on the Y2 side of the reference plane PL. That is, two of the optical systems 22 are disposed on one side and the other side of the reference plane PL.

[0063] The sensor 23 detects light over time and transmits output data to the control device 7 every predetermined time.

[0064] The rejecting device 30 is a device that rejects granular material G that has been determined to be defective. The rejecting device 30 is composed of an air blowing device 31. The air blowing device 31 has a plurality of injection ports S arranged in the left-right direction of the device. The injection ports S are arranged at positions corresponding to the granular material G that falls from the plurality of grooves of the chute 12.

[0065] [Control device] The control device 7 is an ECU, and includes a pass / fail judgment unit 7a, a storage unit 7f, and a rejection control unit 7j, as shown in Fig. 3. The control device 7 is connected to the inspection unit 4 and the operation and display device 6, and is configured to be able to control them. The control device 7 includes a memory (such as a HDD or non-volatile RAM, not shown) that stores programs and control parameters corresponding to the above-mentioned functional units, and a CPU (not shown) that executes the programs. The functions of each functional unit are realized by the CPU executing the programs. The control device 7 may be configured of multiple ECUs that can communicate with each other.

[0066] The quality determination unit 7a determines whether the granular material G is normal or defective based on the output of the sensor 23 received by the control device 7. Details of the operation of the quality determination unit 7a and other functional units will be described later with reference to Figs.

[0067] The storage unit 7f stores, for example, operation parameters of the inspection unit 4, threshold values ​​used to determine whether the granular body G is good or bad, and the like.

[0068] The removal control unit 7j controls the operation timing of the removal device 30 (air blowing device 31).

[0069] [Determining whether granular material is good or bad] The quality judgment of granular materials and the removal of defective products performed by the inspection unit 4 will be described with reference to Figures 4 and 5. Figure 4 is a schematic diagram of the inspection area IA viewed from the front of the device in a direction perpendicular to the left-right direction of the body and the Z direction, with the right side of the figure corresponding to the right side of the device and the top of the figure corresponding to the Z1 side.

[0070] The granular material discharged from the grooves of the chute 12 falls in the Z2 direction, passes through the inspection area IA, and passes in front of the air blowing device 31. The paths along which the granular material moves are referred to as paths R1, R2, R3, ... Rn from the left. n is the same as the number of grooves in the chute 12.

[0071] The nozzles S of the air blowing device 31 are arranged to correspond to each of the routes R1 to Rn. The nozzles S corresponding to the routes R1, R2, ... Rn are referred to as nozzles S1, S2, S3, ... Sn. In other words, the granular material falling along the route R1 passes in front of the nozzle S1.

[0072] As described above, the light from the inspection area IA travels along the optical axis 24 and reaches the surface of the sensor 23. In this embodiment, the sensor 23 is a line sensor and has a number of pixels E1, E2, ... Em arranged in a row. m is the total number of pixels the sensor 23 has. The light detected by the sensor 23 is the light that is emitted from the inspection area IA, travels along the optical axis 24, and passes through the optical axis passing parts 21E, 21F, 21G, and 21H. The light is emitted from a long and narrow area extending in the left-right direction of the device in the inspection area IA. This area is referred to as the detection area DU. In the following description, the light from the detection area DU is assumed to be incident on the front upper sensor 23A. The multiple pixels E1, E2, ... Em of the front upper sensor 23A are arranged along a direction corresponding to the parallel direction (the left-right direction of the device) of the granular material in the inspection area IA (detection area DU).

[0073] An example of the output of the front upper sensor 23A is shown in the lower part of Fig. 4. In the illustrated example, a drop in output is observed at two points in the output of the front upper sensor 23A. This is because the granular material G1 falling along the path R2 and the granular material G2 falling along the path R4 are located in the detection area DU, and light from the granular material G1 and the granular material G2 is incident on the front upper sensor 23A. In other words, the intensity of the light reflected from (or transmitted through) the granular material and incident on the front upper sensor 23A is smaller than the intensity of the background light (light from the diffuse transmission member 21B). In this way, when a granular material passes through the detection area DU, a change occurs in the output of the sensor 23.

[0074] FIG. 5 shows an example in which the granular material G1 is a defective product. In the illustrated example, the granular material G1 is a resin pellet, and has a normal area A1, a colored area A2, and a black area A3. The color of the colored area A2 is darker than the color of the normal area A1. Therefore, the intensity of light from the colored area A2 is less than the intensity of light from the normal area A1. The color of the black area A3 is darker than the color of the colored area A2. Therefore, the intensity of light from the black area A3 is less than the intensity of light from the colored area A2. When the granular material G1 is in the position of FIG. 5 relative to the detection area DU, the output of the front upper sensor 23A has an area where the output is reduced due to the normal area A1, the colored area A2, and the black area A3.

[0075] Specifically, background light (light from the diffuse transparent member 21B) is incident on pixels E41-E44. The outputs of pixels E41-E44 are smaller than the upper second threshold SU2 and larger than the granular material detection threshold SH. Light from the normal region A1 is incident on pixels E45-47, E53-54, and E57-58. The outputs of these pixels are smaller than the granular material detection threshold SH and larger than the lower second threshold SL2. Light from the colored region A2 is incident on pixels E48-52. The outputs of these pixels are smaller than the lower second threshold SL2 and larger than the lower first threshold SL1. Light from the black region A3 is incident on pixels E55-56. The outputs of these pixels are smaller than the lower first threshold SL1.

[0076] The quality determination unit 7a determines that the granular body is defective when there is a pixel in the output of the front upper sensor 23A whose output is smaller than the lower first threshold value SL1 or the lower second threshold value SL2. In detail, the quality determination unit 7a determines that the granular body is defective related to the lower first defect when there is a pixel in the output of the front upper sensor 23A whose output is smaller than the lower first threshold value SL1. The lower first defect is, for example, a "black color abnormality." The quality determination unit 7a determines that the granular body is defective related to the lower second defect when there is a pixel in the output of the front upper sensor 23A whose output is smaller than the lower second threshold value SL2. The lower second defect is, for example, a "coloring abnormality."

[0077] In addition, the quality determination unit 7a determines that the granular material is defective when there is a pixel in the output of the front upper sensor 23A whose output is greater than the upper first threshold value SU1 or the upper second threshold value SU2. In detail, the quality determination unit 7a determines that the granular material is defective related to the upper first defect when there is a pixel in the output of the front upper sensor 23A whose output is greater than the upper first threshold value SU1. The upper first defect is, for example, "glass." The quality determination unit 7a determines that the granular material is defective related to the upper second defect when there is a pixel in the output of the front upper sensor 23A whose output is greater than the upper second threshold value SU2.

[0078] Here, the quality determination unit 7a may perform quality determination based on the number of pixels whose output is below the threshold in addition to the magnitude of the output relative to the threshold. For example, the quality determination unit 7a determines that the granular body is a defective product related to the lower first defect when the output of the front upper sensor 23A includes pixels whose output is smaller than the lower first threshold SL1 and the number of such pixels is greater than the lower first quantity threshold. The quality determination unit 7a determines that the granular body is a defective product related to the lower second defect when the output of the front upper sensor 23A includes pixels whose output is smaller than the lower second threshold SL2 and the number of such pixels is greater than the lower second quantity threshold. The quality determination unit 7a determines that the granular body is a defective product related to the upper first defect when the output of the front upper sensor 23A includes pixels whose output is larger than the upper first threshold SU1 and the number of such pixels is greater than the upper first quantity threshold. The pass / fail judgment unit 7a judges that the granular material is a defective product related to the upper side second defect when there is a pixel in the output of the front upper sensor 23A whose output is greater than the upper side second threshold value SU2 and the number of such pixels is greater than the upper side second quantity threshold value.

[0079] The quality determining unit 7a determines the quality of the granular material based on the outputs of the rear-upper sensor 23B, the rear-lower sensor 23C, and the front-lower sensor 23D, in the same manner as in the case of the output of the front-upper sensor 23A described above.

[0080] 〔channel〕 The quality judgement unit 7a judges the quality of the granular material for each of the multiple paths R1, R2, ... Rn based on the output of the sensor 23. Specifically, the quality judgement unit 7a distributes the multiple pixels E1, E2, ... Em of the sensor 23 to correspond to the multiple parallel paths R1, R2, ... Rn to set multiple channels CH1, CH2, ... CHn, and judges the quality of the granular material for each of the multiple channels. That is, the multiple channels CH1, CH2, ... CHn correspond to the multiple paths R1, R2, ... Rn and the multiple injection ports S1, S2, ... Sn of the air blowing device 31 (removal device 30).

[0081] In the example of FIG. 5, light from a portion of the detection area DU that overlaps with path R2 is incident on pixels E41-63 in the front upper sensor 23A. Therefore, pixels E41-63 corresponding to path R2 are set as channel CH2. A predetermined number of pixels up to pixel E40 corresponding to path R1 are set as channel CH1. A predetermined number of pixels from pixel E64 onwards corresponding to path R3 are set as channel CH3. The channels are initially set when the device is manufactured. Set values ​​for the distribution of pixels E1, E2, .... Em to channels CH1, CH2, .... CHn are stored in memory unit 7f.

[0082] When the above-mentioned judgment criteria are satisfied in a portion of the output of the front upper sensor 23A corresponding to a certain channel, the quality judging unit 7a judges that the granular material in the path corresponding to that channel is defective. Then, the quality judging unit 7a operates the air blowing device 31 (removal device 30) to inject air from the nozzle S corresponding to that channel. In detail, the quality judging unit 7a operates the air blowing device 31 after a predetermined time has elapsed since it judged that the granular material is defective.

[0083] Similarly, the quality determination unit 7a performs quality determination for each of the multiple paths R1, R2, ...Rn of the granular material based on the outputs of the other sensors 23. Specifically, the quality determination unit 7a distributes the multiple pixels E1, E2, ...Em of the rear-upper sensor 23B, the rear-lower sensor 23C, and the front-lower sensor 23D to correspond to the multiple parallel paths R1, R2, ...Rn, to set multiple channels CH1, CH2, ...CHn, and determines the quality of the granular material for each of the multiple channels.

[0084] That is, the channel distribution of the front upper sensor 23A, the rear upper sensor 23B, the rear lower sensor 23C, and the front lower sensor 23D is set so that channels with the same numbers correspond to the inspection paths R and the injection ports S with the same numbers. Note that the number and number of pixels E distributed to the same channel number may be different among the sensors 23.

[0085] The set values ​​of pixel distribution for the channels in each sensor 23 are stored in memory 7f. The quality determination unit 7a reads data indicating the correspondence between channels and pixels from memory 7f, and performs quality determination for each channel of the granular material based on the output of each sensor.

[0086] The pass / fail judgment unit 7a may be configured to determine that when it judges that at least one of the outputs of the four sensors 23 for a certain channel is defective, the granular material in the path corresponding to that channel is defective.

[0087] [Sensor output synthesis] In this embodiment, the front upper optical system 22A and the front lower optical system 22D are arranged on the same side (Y1 side) of the reference plane PL with their respective optical axes 24 (front upper optical axis 24A and front lower optical axis 24D) intersecting. The quality determination unit 7a determines the quality of the granular material based on the sum of the output of the front upper sensor 23A and the output of the front lower sensor 23D.

[0088] As described above, the output of the sensor 23 is divided into a plurality of channels corresponding to a plurality of inspection routes R. The quality determination unit 7a calculates the sum of the output of the front upper sensor 23A and the output of the front lower sensor 23D so as to add up the outputs belonging to the same inspection route R. Then, the quality determination unit 7a determines the quality of the granular material for each channel based on the calculated sum of the outputs.

[0089] 6 shows an example of the output of the front upper sensor 23A, the output of the front lower sensor 23D, and the sum of them. In the illustrated example, the output of the sensor 23 is shown when a normal granular material G2 and a defective granular material G3 pass through the inspection area IA.

[0090] The color of the defective granular material G3 is slightly darker than that of the normal granular material G2. In the output of the front upper sensor 23A and the output of the front lower sensor 23D, the amount of background light is about 100, the amount of inspection light from the granular material G2 (normal product light amount) is about 50, and the amount of inspection light from the granular material G3 (defective product light amount) is about 45.

[0091] In order to distinguish between normal products (granular material G2) and defective products (granular material G3) in the output of the front upper sensor 23A and the output of the front lower sensor 23D, the discrimination threshold must be set between 50 and 45, for example 48. The difference between the threshold and the amount of light for normal products is 2, and the difference between the threshold and the amount of light for defective products is 3.

[0092] Here, the output of the sensor 23 may vary due to fluctuations in the amount of light from the lighting device 21, fluctuations in the color of the granular material (individual differences), electrical noise, etc. When the discrimination threshold is 48, if the output of the sensor 23 is smaller than 48, the granular material is determined to be defective. In that case, even if the granular material is normal, if there are pixels whose output is below 48 due to the above-mentioned output fluctuations, the granular material will be determined to be defective. If the threshold is reduced (for example, 46) to suppress this false detection (determining a normal product as defective), the possibility of erroneously determining that a defective granular product is normal increases.

[0093] The sum of the output of the front upper sensor 23A and the output of the front lower sensor 23D (hereinafter referred to as the "composite output") is shown in the lower part of Fig. 6. In the composite output, the amount of background light is about 200, the amount of inspection light from the granular material G2 (amount of light for a normal product) is about 100, and the amount of inspection light from the granular material G3 (amount of light for a defective product) is about 90.

[0094] In order to distinguish between normal products (granular material G2) and defective products (granular material G3) in the composite output, the discrimination threshold must be between 100 and 90, for example 95. The difference between the threshold and the amount of light for normal products is 5, and the difference between the threshold and the amount of light for defective products is 5.

[0095] As described above, the difference between the amount of light for a normal product and the amount of light for a defective product in the output of the front upper sensor 23A and the output of the front lower sensor 23D was 5. In contrast, the difference between the amount of light for a normal product and the amount of light for a defective product in the composite output is 10. As a result, the difference (5) between the threshold value and the amount of light for a normal product and the difference (5) between the threshold value and the amount of light for a defective product in the composite output are greater than the difference (2) between the threshold value and the amount of light for a normal product and the difference (3) between the threshold value and the amount of light for a defective product in the output of the front upper sensor 23A and the output of the front lower sensor 23D. Therefore, the possibility of erroneous determination in the composite output is smaller than the possibility of erroneous determination in the output of the front upper sensor 23A and the output of the front lower sensor 23D. Therefore, the inspection accuracy of the granular material inspection device is improved.

[0096] Other Embodiments In the following description of other embodiments, the same components as those in the above-described embodiment are denoted by the same reference numerals, and the description of those components may be omitted.

[0097] (1) In the above embodiment, the quality determination unit 7a calculates the sum of the output of the front upper sensor 23A and the output of the front lower sensor 23D, and determines the quality of the granular material based on the calculated sum. The quality determination unit 7a may be configured to calculate the product (composite output) of the output of the front upper sensor 23A and the output of the front lower sensor 23D, and determine the quality of the granular material based on the calculated product. In this embodiment as well, the difference between the amount of light of a normal product and the amount of light of a defective product in the composite output is larger than the difference in the output of the sensor 23. Therefore, the inspection accuracy of the granular material inspection device is improved.

[0098] (2) In the above embodiment, a granular material inspection device has been described that includes four optical systems 22 and sensors 23. The granular material inspection device may include three or five or more optical systems 22 and sensors 23. Also, a configuration in which the granular material inspection device includes two optical systems (front upper optical system 22A and front lower optical system 22D) and two sensors (23A, 23D) is also possible.

[0099] (3) The quality determination unit 7a may be configured to calculate the sum or product (composite output) of the output of the rear-upper sensor 23B and the output of the rear-lower sensor 23C, and determine the quality of the granular material based on the calculated composite output.

[0100] (4) The quality determination unit 7a may be configured to determine the quality of the granular material based on both the combined output of the front upper sensor 23A and the front lower sensor 23D and the combined output of the rear upper sensor 23B and the rear lower sensor 23C.

[0101] (5) The quality determination unit 7a may be configured to calculate a composite output of the front upper sensor 23A and the front lower sensor 23D at different times. Since the front upper optical axis 24A and the front lower optical axis 24D are not parallel, the timing at which the falling granular material G intersects with the optical axis 24 may differ between the front upper optical axis 24A and the front lower optical axis 24D. Specifically, after the granular material G begins to intersect with the front upper optical axis 24A, the granular material G begins to intersect with the front lower optical axis 24D. The quality determination unit 7a may be configured to calculate a composite output of the output of the front upper sensor 23A at a certain time and the output of the front lower sensor 23D at a time a predetermined time after the time.

[0102] (6) In the above embodiment, the four optical axes 24 (front-upper optical axis 24A, rear-upper optical axis 24B, rear-lower optical axis 24C, and front-lower optical axis 24D) intersect at one point on the inspection path R. Other configurations are also possible. For example, the front-upper optical axis 24A and the rear-upper optical axis 24B may intersect at one point on the inspection path R, and the rear-lower optical axis 24C and the front-lower optical axis 24D may intersect at another point on the inspection path R. In other words, the intersection of two optical axes 24 may be different from the intersection of the other two optical axes 24. The intersection of the optical axes 24 does not have to be on the inspection path R.

[0103] (7) In the above embodiment, the sensor 23 is a line sensor. The sensor 23 may be an area sensor capable of acquiring a two-dimensional image. The sensor 23 may be a monochrome or color sensor. The sensor 23 may be a CCD or a CMOS sensor.

[0104] (8) In the above embodiment, the lighting units 21C and 21D are LEDs. The lighting units 21C and 21D may be cold cathode fluorescent lamps, hot cathode fluorescent lamps, organic electroluminescence (EL) lamps, etc.

[0105] (9) It is preferable that the outputs that the quality judging unit 7a judges to be the object of quality judging can be arbitrarily set. That is, it is preferable that it is possible to set whether the quality judging unit 7a judges to be the object of quality judging for each of the output of the front upper sensor 23A, the output of the rear upper sensor 23B, the output of the rear lower sensor 23C, the output of the front lower sensor 23D, the combined output of the front upper sensor 23A and the front lower sensor 23D, and the combined output of the rear upper sensor 23B and the rear lower sensor 23C.

[0106] (10) The granular material may be a transparent or translucent resin pellet. In this case, the illumination device 21 is configured so that light transmitted through the interior of the granular material is guided to the sensor 23 as inspection light by the optical system 22. For example, the illuminance of the illumination device 21 is appropriately adjusted by the control device 7.

[0107] For example, lighting units 21C and 21D may be turned off and background lighting units 21L, 21M, 21P, and 21Q may be turned on. In this case, light from background lighting units 21L, 21M, 21P, and 21Q passes through the inside of the granular body and enters four sensors 23.

[0108] For example, the illumination unit 21C may be turned off and the illumination unit 21D may be turned on. In this case, the light from the diffuse transmission member 21B passes through the inside of the granular material and enters the front upper sensor 23A and the front lower sensor 23D. The light from the diffuse transmission member 21B is reflected by the surface of the granular material and enters the rear upper sensor 23B and the rear lower sensor 23C. [Industrial Applicability]

[0109] The present invention is applicable to devices for inspecting granular materials (granular material inspection devices, color sorters, optical sorters, etc.). [Explanation of symbols]

[0110] 7a: Good / bad judgement section 10: Delivery device 21: Lighting equipment 22:Optical system 22A: Front upper optical system (example of the first optical system) 22B: Rear upper optical system (example of the third optical system) 22C: Rear-inferior optical system (example of the fourth optical system) 22D: Front-lower optical system (example of the second optical system) 23: Sensor 23A: Front upper sensor (example of the first sensor) 23B: Rear upper sensor (example of the third sensor) 23C: Rear lower sensor (example of the 4th sensor) 23D: Front lower sensor (example of second sensor) 24: Optical axis CH1: Channel CH2: Channel CH3: Channel G: Granular object (object to be inspected) IA: Inspection area PL:Reference plane R: Inspection route

Claims

1. An inspection apparatus comprising two or more sensors and two or more optical systems, a sending device capable of sending the object to be inspected to a plurality of parallel inspection paths in a reference plane so as to pass through an inspection area; a first sensor and a second sensor as the sensors for detecting light from the inspection area; a first optical system as the optical system that guides inspection light from the inspection area to the first sensor; a second optical system as the optical system that guides inspection light from the inspection area to the second sensor; a third sensor and a fourth sensor for detecting light from the inspection area; a third optical system that guides inspection light from the inspection area to the third sensor; a fourth optical system that guides inspection light from the inspection area to the fourth sensor; a quality determination unit for determining the quality of the object to be inspected, the first optical system and the second optical system are disposed on the same side of the reference plane with their optical axes intersecting each other; the third optical system and the fourth optical system are disposed on an opposite side of the reference plane from the first optical system and the second optical system, with their optical axes intersecting each other; The quality determination unit of the inspection device determines the quality of the object to be inspected based on the sum or product of the output of the first sensor and the output of the second sensor, and the sum or product of the output of the third sensor and the output of the fourth sensor.

2. The outputs of the plurality of sensors are divided into a plurality of channels corresponding to the plurality of inspection paths; The inspection device according to claim 1 , wherein the quality determining unit calculates a sum or a product of outputs from the plurality of sensors so that outputs belonging to the channels corresponding to the same inspection path are added together.

3. An illumination device that irradiates light onto the inspection area, 3. The inspection apparatus according to claim 1, wherein the illumination device is configured so that light reflected from a surface of the object to be inspected is guided as the inspection light to the plurality of sensors by the plurality of optical systems.

4. An illumination device that irradiates light onto the inspection area, 4. The inspection apparatus according to claim 1, wherein the illumination device is configured such that light transmitted through the inside of the object to be inspected is guided as the inspection light to the plurality of sensors by the plurality of optical systems.

5. 5. The inspection apparatus according to claim 1, wherein the plurality of optical systems are configured to optically aim at approximately the same location within the inspection region.

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