JP2025017230A - X-ray inspection equipment - Google Patents

Abstract

To provide an X-ray inspection device that can maintain the accuracy of X-ray transmission images even when there is a gap between two conveyor sections that are spaced apart in a width direction in a conveyance unit.SOLUTION: An X-ray inspection device 1 includes: a conveyance unit 5 that supports and conveys an item G across a first conveyor surface 51a and a second conveyor surface 52a; an X-ray detection part 7 that detects a first X-ray F1 that passes through the item G without passing through either a first conveyor section 51 or a second conveyor section 52, and a second X-ray F2 that passes through both the item G and either the first conveyor section 51 or the second conveyor section 52 in the X-rays; a control part 10 that inspects the item G on the basis of a detection signal in the X-ray detection part 7; and an attenuation member 70 that applies attenuation characteristics equivalent to the attenuation characteristics in a case where the first X-ray F1 passes through either the first conveyor section 51 or the second conveyor section 52 to the first X-ray F1.SELECTED DRAWING: Figure 6

Description

The present invention relates to an X-ray inspection device.

In an X-ray inspection device, the object to be inspected is transported in a horizontal direction by a conveyor belt, and X-rays are irradiated when the object to be inspected passes through a gap extending in a direction perpendicular to the transport direction, and detection data of the X-rays that have passed through the object to be inspected is obtained (see, for example, Patent Document 1).

JP 2009-109229 A

In the conventional device described above, inclined guides and side guides are placed on both sides of the conveyor belt to irradiate the X-rays at an angle to the object to be inspected. The inner edges of these guides form a belt holding section with a roughly V-shaped cross section perpendicular to the conveying direction, so that the ridge of the object to be inspected comes into stable contact with the V-shaped recess in the conveyor belt.

Incidentally, instead of the above-mentioned guide member, the conveying means (conveying unit) itself may have two conveying surfaces (conveying sections) spaced apart from each other in a direction perpendicular to the conveying direction. The two conveying surfaces extend in the conveying direction, and the article is conveyed in a position straddling the two conveying surfaces. A certain gap exists between the two conveying sections. X-rays are irradiated in a predetermined area extending in a direction perpendicular to the conveying direction (called the width direction), and the X-rays that have passed through the article are detected by the X-ray detection section. In this configuration, there are parts in the width direction where the conveying means exists and parts where the conveying means does not exist. Therefore, the basic amount of X-rays (in other words, brightness) that reaches the X-ray detection section may not be uniform in the width direction, but may differ from part to part. As a result, a problem occurs in that the accuracy of the X-ray transmission image of the article decreases.

The present invention aims to provide an X-ray inspection device that can maintain the accuracy of X-ray transmission images even when a gap exists between two conveying sections that are separated in the width direction in a conveying unit.

[1] An X-ray inspection device according to one aspect of the present invention includes a transport unit that transports an object in a transport direction, the transport unit having a first transport section and a second transport section that are spaced apart in a horizontal direction perpendicular to the transport direction, and that transports an object straddling a first transport surface of the first transport section and a second transport surface of the second transport section while supporting the object; an X-ray detection section that detects, among the X-rays irradiated to the object, a first X-ray that has passed through the object without passing through either the first transport section or the second transport section, and a second X-ray that has passed through both the first transport section or the second transport section and the object; an inspection section that inspects the object based on a detection signal in the X-ray detection section; and an attenuation section that imparts, to either the first X-ray or the first detection signal corresponding to the first X-ray, attenuation characteristics equivalent to the attenuation characteristics when the first X-ray has passed through either the first transport section or the second transport section.

According to the X-ray inspection device of [1], the X-ray detection unit detects the first X-ray and the second X-ray. The first X-ray is different from the second X-ray in the sense that it does not pass through either the first transport unit or the second transport unit (due to passing through the gap between the transport units). Therefore, the attenuation unit imparts to either the first X-ray or the first detection signal corresponding to the first X-ray an attenuation characteristic equivalent to the attenuation characteristic when the first X-ray passes through either the first transport unit or the second transport unit. This makes the basic amount of X-rays (in other words, brightness) that reaches the X-ray detection unit uniform. Even if there is a gap between two transport units that are separated in the width direction in the transport unit, the accuracy of the X-ray transmission image can be maintained. In the X-ray inspection device of [1], the attenuation unit may be provided outside the inspection unit or may be provided in the inspection unit.

[2] In the X-ray inspection device of [1] above, the attenuation unit may be an attenuation member that is disposed in a region connecting the X-ray irradiation unit and the contour of the gap between the first transport unit and the second transport unit and attenuates the first X-ray. In this case, since the attenuation member attenuates the first X-ray, it is possible to make the brightness uniform by simply adding one physical component.

[3] The X-ray inspection device of [2] above may further include a housing that houses the X-ray detection unit, and the damping member may be disposed within the housing. In this case, even if foreign matter (sand, soil, dust, etc.) falls through the gap between the transport units, the foreign matter is less likely to accumulate on the damping member.

[4] The X-ray inspection device of [3] above may be provided with an air nozzle that sprays air toward the upper surface of the housing that vertically intersects with the attenuation member. The air nozzle prevents the accumulation of foreign matter on the upper surface of the housing or the surface of the plate member.

[5] In the X-ray inspection device of [1] above, the inspection unit may include a signal acquisition unit that acquires detection signals in the X-ray detection unit, a reduction processing unit that reduces only the detection value in a first detection signal among the detection signals, and an image generation unit that generates an X-ray transmission image of the item based on the first detection signal that has been reduced in the reduction processing unit and a second detection signal corresponding to the second X-ray. In this case, the reduction processing unit of the inspection unit reduces only the detection value in the first detection signal (imparting the above-mentioned attenuation characteristic). This makes it possible to make the brightness uniform by signal processing in the inspection unit (i.e., by only a software mechanism) without adding any physical configuration.

According to the present invention, the accuracy of X-ray radiographic images can be maintained even when a gap exists between two conveying sections that are separated in the width direction in the conveying unit.

FIG. 1 is a perspective view of an X-ray inspection apparatus according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the transport unit in FIG. 1 taken along a plane perpendicular to the transport direction. FIG. 3 is a perspective view of a connecting member attached to a housing of the inspection unit and a frame of the transport unit. FIG. 4 is a diagram showing the positional relationship between the connecting member and the frame as viewed from below. FIG. 5 is a cross-sectional view showing a plate member and a shielding member provided on a wall of the housing. FIG. 6 is a cross-sectional view of the X-ray inspection apparatus taken along a vertical plane passing through an area where X-rays pass. FIG. 7 is a block diagram showing a configuration of an X-ray inspection apparatus according to another embodiment in which an attenuation unit is provided in a control unit (inspection unit). FIG. 8 is a diagram showing a process of reducing the first detection signal in the control unit (inspection unit) of FIG.

Embodiments of the present invention will be described below with reference to the drawings. Note that in the description of the drawings, the same elements are given the same reference numerals, and duplicate descriptions will be omitted.

As shown in FIG. 1, the X-ray inspection device 1 includes an apparatus body 2, support legs 3, and a transport unit 5. The support legs 3 support the apparatus body 2. The apparatus body 2 has a housing 9 made of a material capable of blocking electromagnetic waves such as X-rays. The housing 9 includes, for example, an upper part 9a having a display operation unit 8 on the front side, a back part 9b extending in the vertical direction, and a lower part 9c protruding forward from the back part 9b.

The X-ray inspection device 1 includes an inspection unit 15 built into the device body 2. The inspection unit 15 has an inspection chamber 4 provided at approximately the center of the height direction of the device body 2. The inspection chamber 4 is provided with, for example, a shielding box (not shown). The inspection unit 15 has an X-ray irradiation unit 6 and an X-ray detection unit 7 housed in a housing 9 of the device body 2. The X-ray irradiation unit 6 is disposed in an upper part 9a of the housing 9, and the X-ray detection unit 7 is disposed in a lower part 9c of the housing 9. The inspection unit 15 further includes a control unit 10 provided, for example, in the upper part 9a of the housing 9.

When viewed from the upstream side in the transport direction A, the first wall 91 of the upper portion 9a, the second wall 92 of the back portion 9b, and the third wall 93 of the lower portion 9c form a U-shape that opens forward. The inspection chamber 4 is a roughly rectangular parallelepiped space surrounded by these walls. A rectangular entrance opening 4a is formed at the upstream end of the inspection chamber 4 in the transport direction A. A rectangular exit opening 4b is formed at the downstream end of the inspection chamber 4 in the transport direction A. The shape and size of the entrance opening 4a are equal to the shape and size of the exit opening 4b. The front of the inspection chamber 4 is covered by a shielding cover (not shown) that is opened and closed during maintenance, for example.

The transport unit 5 transports the item G (see FIG. 2) in the transport direction A. The transport unit 5 is installed so as to pass through the inspection chamber 4 in the transport direction A. In other words, the inspection unit 15 is arranged so as to cover the transport unit 5.

The X-ray inspection device 1 generates an X-ray transmission image of the item G while transporting the item G by the transport unit 5, and performs inspection of the item G (for example, inspection of the number of items stored, inspection of foreign matter contamination, inspection of missing items, inspection of cracks and chips, etc.) based on the X-ray transmission image. The transport unit 5 has an input section 20 arranged upstream in the transport direction A, and an output section 30 arranged downstream in the transport direction A. The item G before inspection is transported into the inspection room 4 by the input section 20. The item G after inspection is transported out of the inspection room 4 by the output section 30. The item G determined to be defective by the X-ray inspection device 1 is sorted out of the production line by a sorting device (not shown) arranged downstream of the output section 30. The item G determined to be non-defective by the X-ray inspection device 1 passes through the sorting device as is.

The X-ray irradiation unit 6 irradiates X-rays (electromagnetic waves) to the object G transported by the transport unit 5. The X-ray irradiation unit 6 has, for example, an X-ray tube that emits X-rays and a collimator that spreads the X-rays emitted from the X-ray tube in a fan shape in a plane perpendicular to the transport direction A. The X-ray detection unit 7 detects the X-rays that are irradiated by the X-ray irradiation unit 6 and transmitted through the object G. The X-ray detection unit 7 is configured, for example, as a line sensor. Specifically, the X-ray detection unit 7 has a plurality of photodiodes arranged one-dimensionally along a horizontal direction perpendicular to the transport direction A, and a scintillator arranged on the X-ray incident side of each photodiode. In this case, in the X-ray detection unit 7, the X-rays incident on the scintillator are converted into light, and the light incident on each photodiode is converted into an electrical signal.

The display operation unit 8 is provided on the upper part 9a of the housing 9 and faces forward. The display operation unit 8 displays various information (i.e., notifies the operator of the operating status) and accepts input of various conditions. The display operation unit 8 is, for example, a liquid crystal display, and displays an operation screen as a touch panel. In this case, the operator can input various conditions via the display operation unit 8. The display operation unit 8 notifies of various abnormalities in the X-ray inspection device 1. An alarm light 11, which also functions as an alarm unit, is provided on the upper part 9a of the housing 9.

The control unit 10 is disposed in the device main body 2. The control unit 10 controls the operation of each part of the X-ray inspection device 1. The control unit 10 is composed of a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc. The control unit 10 receives signals output from the X-ray detection unit 7 and A/D converted. The control unit 10 generates an X-ray transmission image of the item G based on the signal output from the X-ray detection unit 7, and functions as an inspection unit that inspects the item G based on the X-ray transmission image.

Next, the transport unit 5 will be described in detail with reference to Figs. 1 to 4. Fig. 2 shows a cross section of the loading section 20 as viewed from the downstream side of the transport direction A. As shown in Figs. 1 and 2, the transport unit 5 has a first transport section 51 and a second transport section 52 that are spaced apart in a horizontal direction (left-right direction in Fig. 2) perpendicular to the transport direction A. The first transport section 51 is arranged, for example, on the rear side (close to the second wall section 92), and the second transport section 52 is arranged, for example, on the front side (front side of the inspection room 4). The transport unit 5 transports an item G straddling the first transport surface 51a of the first transport section 51 and the second transport surface 52a of the second transport section 52 while supporting it. That is, the item G has a diameter larger than the gap C between the first transport surface 51a and the second transport surface 52a. The item G is supported by the first transport surface 51a and the second transport surface 52a while positioned above the gap C.

In the conveying unit 5 of this embodiment, for example, the first conveying section 51 and the second conveying section 52 are both inclined. In the conveying unit 5, the horizontal direction perpendicular to the conveying direction A is defined as the "width direction". The gap C is formed in the center of the width direction. The gap C having a constant or approximately constant width extends in the conveying direction A. As shown in FIG. 2, the first conveying section 51 includes a first conveying belt B1 forming a first conveying surface 51a. The second conveying section 52 includes a second conveying belt B2 forming a second conveying surface 52a. The first conveying belt B1 and the second conveying belt B2 are each provided across the above-mentioned carry-in section 20 and carry-out section 30. On the other hand, the first conveying section 51 has a first frame 21 included in the carry-in section 20 and a first frame 31 included in the carry-out section 30 (see FIG. 4). The second transport section 52 has a second frame 22 included in the loading section 20 and a second frame 32 included in the unloading section 30 (see FIG. 4).

As shown in FIG. 4, the first frame 21 and the first frame 31 are spaced apart in the conveying direction A. The second frame 22 and the second frame 32 are spaced apart in the conveying direction A. The position of the space Y1 between the first frames 21 and 31 and the position of the space Y2 between the second frames 22 and 32 are aligned in the conveying direction A. An X-ray passage area X is formed through the spaces Y1 and Y2, from the X-ray irradiation unit 6 to the X-ray detection unit 7. However, one first conveying belt B1 extends beyond the space Y1. One second conveying belt B2 extends beyond the space Y2. Note that in FIG. 4, in order to make the arrangement of the frames easier to see, only the back rails B1a and B2a of the first conveying belt B1 and the second conveying belt B2 are shown.

As shown in FIG. 2, the endless first conveyor belt B1 includes an upper portion that moves in the conveying direction A and forms the first conveying surface 51a, and a lower portion that moves in the opposite direction to the conveying direction A. The endless second conveyor belt B2 includes an upper portion that moves in the conveying direction A and forms the second conveying surface 52a, and a lower portion that moves in the opposite direction to the conveying direction A. Unless otherwise specified below, the explanations given for each of the first conveyor belt B1 and the second conveyor belt B2 are for the upper portions.

The first frame 21 of the first conveying section 51 supports and guides the first conveying belt B1. The second frame 22 of the second conveying section 52 supports and guides the second conveying belt B2. The first frame 21 includes a groove 21e that receives the back rail B1a and positions the first conveying belt B1. The second frame 22 includes a groove 22e that receives the back rail B2a and positions the second conveying belt B2. The grooves 21e and 22e each extend in the conveying direction A. The back rails B1a and B2a fit into the grooves 21e and 22e to prevent the first conveying belt B1 and the second conveying belt B2 from meandering. The first frame 31 and the second frame 32 also have the same shape and arrangement as shown in FIG. 2. The cross-sectional shape of each of these frames is not particularly limited, and various known shapes may be adopted. Each frame may have notches or the like formed at multiple locations in the conveying direction A.

The inner end B1b of the first conveying belt B1 is lower than the outer end B1c. The inner end B2b of the second conveying belt B2 is lower than the outer end B2c. Similarly, the inner end 21b of the first frame 21 is lower than the outer end 21c. The inner end 22b of the second frame 22 is lower than the outer end 22c. The first conveying section 51 and the second conveying section 52 having the above configuration constitute a V-shaped conveyor. The first conveying section 51 and the second conveying section 52 are likely to support items G that are easy to roll (such as circular or rounded items). The V-shape of the first conveying surface 51a and the second conveying surface 52a shown in FIG. 2 is maintained throughout the entire conveying direction A. The inclination angle (angle with respect to the horizontal plane) of the first conveying section 51 and the second conveying section 52 (the first conveying surface 51a and the second conveying surface 52a) may be set appropriately. In this specification, the terms "inner end" and "outer end" in relation to the frames (conveyor frames) of the first conveying section 51 and the second conveying section 52 are based on the position in the width direction.

As shown in FIG. 4, the passing area X formed between the first frames 21, 31 and between the second frames 22, 32 extends along direction D when viewed from below. Direction D is a direction that intersects both the conveying direction A in the conveying unit 5 and the opposing direction (the direction perpendicular to the paper surface of FIG. 4) in which the X-ray irradiation unit 6 and the X-ray detection unit 7 face each other. In this embodiment, conveying direction A and direction D are horizontal directions, and the opposing direction of the X-ray irradiation unit 6 and the X-ray detection unit 7 is the up-down direction (vertical direction). Direction D is the width direction mentioned above.

3 and 4, the pair of first frames 21, 31 and the pair of second frames 22, 32 are arranged side by side with the X-ray passage area X between them. A connecting member 60 is attached to the transport unit 5, which connects the first frames 21, 31 and connects the second frames 22, 32. The connecting member 60 has a pair of base surface parts 61 fixed on the third wall part 93 of the housing 9, a pair of side plate parts 62 erected at the outer end of the width direction of the base surface part 61, a pair of lower support parts 63 provided at the inner end of the width direction of the base surface part 61, and a pair of upper pressing plate parts 64 provided at the upper end of the side plate parts 62. The base surface part 61 and the lower support part 63 have a transverse opening 66 that is rectangular when viewed from below and extends in the width direction so as not to affect the X-rays in the passage area X. The X-ray irradiation part 6 is arranged within the range of the transverse opening 66 when viewed from the lower surface side of the base surface part 61.

A pair of side plate portions 62 are located on the outside of the first conveying portion 51 and the second conveying portion 52 in the width direction. One (rear) side plate portion 62 is fixed to the outer end portion 21c of the first frame 21 and the outer end portion 31c of the first frame 31 with screws or the like, thereby connecting the outer ends 21c, 31c. The other (front) side plate portion 62 is fixed to the outer end portion 22c of the second frame 22 and the outer end portion 32c of the second frame 32 with screws or the like, thereby connecting the outer ends 22c, 32c. One (rear) lower support portion 63 supports the inner end portion 21b of the first frame 21 and the inner end portion 31b of the first frame 31. The other (rear) lower support portion 63 supports the inner end portion 22b of the second frame 22 and the inner end portion 32b of the second frame 32. In FIG. 3, the configuration related to the transport unit 5, such as the conveyor frame, is omitted so that the structure of the connecting member 60 can be easily understood.

A rectangular opening 62e is formed at the bottom of the pair of side plate portions 62, which is continuous with the transverse opening 66. The length of the opening 62e in the conveying direction A is sufficiently larger than the X-ray passing area X. A cylindrical air nozzle 69 extending in the width direction is attached to the upstream side of the opening 62e in the conveying direction A. The air nozzle 69 is arranged upstream of the passing area X so as not to affect the X-rays in the passing area X. The air nozzle 69 has a plurality of injection holes 69a directed slightly downward downstream. The air nozzle 69 is connected to an air source of compressed air via an air pipe (both are omitted from the figure). As a result, air is injected from the air nozzle 69 (toward the downstream side) toward the vicinity of the opening 93e formed in the third wall portion 93 (the upper surface of the housing 9).

The pair of base surface portions 61 and the pair of side plate portions 62 are connected by a mountain-shaped central lower shielding plate 67 and a pair of triangular lateral lower shielding plates 68 arranged at the upstream end of the connecting member 60. The connecting member 60 is an integral structure made of a metal material (e.g., stainless steel) capable of shielding X-rays. In addition, a holding mechanism 120 that holds the inner end 21b of the first frame 21 and the inner end 22b of the second frame 22 is provided on the upstream side of the connecting member 60 in the transport direction A. A holding mechanism 130 that holds the inner end 31b of the first frame 31 and the inner end 32b of the second frame 32 is provided on the downstream side of the connecting member 60.

In this way, the connecting member 60 connects the loading section 20 and the unloading section 30 in the transport direction A and holds them together. Also, the first transport section 51 and the second transport section 52 are connected and held together in the width direction. The connecting member 60 does not have any members that cross the passing area X. No part of the connecting member 60 is captured by the X-ray detection unit 7 during X-ray photography. In this way, the connecting member 60 connects and supports a pair of conveyors separated in the width direction. In particular, the side plate portion 62 and the lower support portion 63 reliably support the V-shaped conveyor.

Furthermore, as shown in Figures 2 and 4, the back rail portion B1a of the first conveyor belt B1 is disposed near the outer end B1c (at a position close to the outer end B1c). The back rail portion B2a of the second conveyor belt B2 is disposed near the outer end B2c (at a position close to the outer end B2c). As a result, the back rail portions B1a, B2a are disposed outside the passing area X so as not to affect the X-rays in the passing area X. The back rail portions B1a, B2a are not captured by the X-ray detection unit 7 during X-ray imaging.

Each of the first conveying section 51 and the second conveying section 52 has a known configuration such as a motor, a pulley, a timing belt, a driving roller, and a driven roller (all not shown). The first conveying section 51 and the second conveying section 52 run the first conveying belt B1 and the second conveying belt B2 at the same moving speed. As a result, the conveying unit 5 conveys the item G at that running speed. The moving speed (each conveying speed) of the first conveying belt B1 and the second conveying belt B2 can be adjusted, for example, manually. The item G is conveyed on the first conveying belt B1 and the second conveying belt B2 (near the inner ends B1b, B2b and above the inner ends B1b, B2b). In this way, the posture of the item G conveyed in the valley part of the V-shaped conveyor is less likely to change. In other words, the item G is less likely to roll on the conveyor. In addition, if fine foreign matter or the like is attached to the item G, the foreign matter or the like may fall off the item G. Any foreign objects that fall out will fall through the gap C between the V-shaped conveyors.

As shown in FIG. 1, the inspection unit 15 inspects the object G by irradiating the object G with X-rays while the object G is moving from the entrance opening 4a to the exit opening 4b. In the inspection unit 15, leakage of X-rays to the outside is prevented by a shielding box and various shielding mechanisms described below. The object G before inspection is carried into the inspection room 4 through the entrance opening 4a. The object G after inspection is carried out of the inspection room 4 through the exit opening 4b.

Next, referring to Figures 5 and 6, the configuration provided below the passage area X formed between the loading section 20 and the unloading section 30 will be described. As shown in Figure 5, the lower part 9c of the housing 9 houses the X-ray detection section 7. The third wall 93 of the lower part 9c, which is the wall facing the transport unit 5, has an opening 93e extending in the direction D to allow X-rays to pass through.

A plate member 54 is provided between the passing area X and the X-ray detection unit 7 (located below the passing area X in the lower part 9c). The plate member 54 is made of a material that can transmit electromagnetic waves such as X-rays. The plate member 54 is, for example, a carbon plate. The plate member 54 may be made of, for example, resin. The opening 93e is located between the passing area X and the X-ray detection unit 7. The plate member 54 includes a rectangular flat base plate portion 54a that is larger than the opening 93e, and a rectangular protruding plate portion 54b that protrudes from the base plate portion 54a and fits into the opening 93e. The plate member 54 allows X-rays to pass through and prevents cleaning water and the like from entering the lower part 9c during maintenance, for example. The protruding plate portion 54b has a rectangular shape slightly smaller than the opening 93e in a plan view. The base plate portion 54a of the plate member 54 faces the back surface 93b of the third wall portion 93, and for example, a gasket (elastic member) 57 is interposed between the base plate portion 54a and the back surface 93b of the third wall portion 93. The gasket 57 enhances the waterproof and dustproof properties of the plate member 54 (at the lower portion 9c).

The plate member 54 and the gasket 57 are fixed to the third wall portion 93 by a rectangular plate-shaped pressing member 56 and a plurality of fastening members 59 arranged below them. A countersunk portion 54f extending in the direction B is formed on the back surface of the central portion of the plate member 54, and in this manner, the plate member 54 is attached to the third wall portion 93, which is a part of the housing 9.

As shown in FIG. 6, the X-ray detection unit 7 detects, among the X-rays irradiated from the X-ray irradiation unit 6, a first X-ray F1 that has passed through the object G without passing through either the first conveyor unit 51 or the second conveyor unit 52, and a second X-ray F2 that has passed through both the first conveyor unit 51 or the second conveyor unit 52 and the object G. At the position shown in the cross-sectional view of FIG. 6, the first frame 21, the second frame 22, the first frame 31, and the second frame 32 do not exist. Therefore, the first X-ray F1 is an X-ray that has passed through the object G without passing through either the first conveyor belt B1 or the second conveyor belt B2. The second X-ray F2 is an X-ray that has passed through both the first conveyor belt B1 or the second conveyor belt B2 and the object G.

As shown in FIG. 5 and FIG. 6, a rectangular attenuation member (attenuation section) 70 made of the same material (or the same material) as the first conveyor belt B1 and the second conveyor belt B2 is attached to the lower surface of the pressing member 56. The attenuation member 70 is disposed in the lower portion 9c of the housing 9. The attenuation member 70 is disposed only in the area connecting the X-ray irradiation section 6 and the contour of the gap C between the first conveyor belt B1 and the second conveyor belt B2. As a result, the attenuation member 70 imparts to the first X-ray F1 attenuation characteristics equivalent to the attenuation characteristics when the first X-ray F1 passes through either the first conveyor belt B1 or the second conveyor belt B2. There is no difference in attenuation factors (attenuation factors) other than the attenuation of the X-ray due to passing through the object G between the first X-ray F1 and the second X-ray F2 that reach the X-ray detection section 7.

According to the X-ray inspection device 1 of this embodiment, the X-ray detection unit 7 detects the first X-ray F1 and the second X-ray F2. The first X-ray F1 is different from the second X-ray F2 in the sense that it does not pass through either the first transport unit 51 or the second transport unit 52 (due to passing through the gap between the transport units). Therefore, the attenuation member 70 imparts to the first X-ray F1 attenuation characteristics equivalent to the attenuation characteristics when the first X-ray F1 passes through either the first transport unit 51 or the second transport unit 52. This makes the basic X-ray amount (in other words, brightness) that reaches the X-ray detection unit 7 uniform. The attenuation member 70 is a means for uniforming the basic X-ray amount. Even if there is a gap between two transport units separated in the width direction in the transport unit 5, the accuracy of the X-ray transmission image can be maintained. In this X-ray inspection device 1, the attenuation member 70 is provided outside the control unit 10 (separate from the control unit 10).

The attenuation member 70 attenuates the first X-ray F1, so the brightness can be made uniform by simply adding one physical component.

The damping member 70 is disposed in the lower portion 9c of the housing 9. This makes it difficult for foreign matter (sand, soil, dust, etc.) to accumulate on the damping member 70 even if the foreign matter falls through the gap C between the transport sections.

The air nozzle 69 also prevents foreign matter from accumulating on the upper surface 93a of the housing 9 and the surface 54c of the plate member 54.

Next, referring to Figs. 7 and 8, an embodiment in which an attenuation function (attenuation section) equivalent to the attenuation member 70 is provided in the control section 10 will be described. In the X-ray inspection device according to another embodiment, the control section 10 includes a signal acquisition section 71 that acquires a detection signal in the X-ray detection section 7, a reduction processing section (attenuation section) 72 that reduces only the detection value in the first detection signal S1 (detection signal corresponding to the first X-ray F1) among the detection signals, an image generation section 73 that generates an X-ray transmission image of the article based on the first detection signal that has been reduced in the reduction processing section 72 and the second detection signal corresponding to the second X-ray F2, and a judgment section 74 that judges the quality of the article G based on the X-ray transmission image.

The control unit 10 imparts to the first detection signal S1 corresponding to the first X-ray F1 attenuation characteristics equivalent to the attenuation characteristics (see the second detection signal S2 shown in FIG. 8) when the first X-ray F1 passes through either the first transport unit 51 or the second transport unit 52. This makes the basic X-ray amount (in other words, brightness) that reaches the X-ray detection unit 7 uniform. The reduction processing unit 72 is a means for homogenizing the basic X-ray amount. Even if there is a gap C between the two transport units that are separated in the width direction in the transport unit 5, the accuracy of the X-ray transmission image can be maintained. In this X-ray inspection device, the attenuation unit is provided in the inspection unit. According to such a control unit 10, the reduction processing unit 72 reduces only the detection value in the first detection signal S1 (imparts the above-mentioned attenuation characteristics) (see FIG. 8). This makes it possible to homogenize the brightness by signal processing in the control unit 10 (i.e., only by a software mechanism) without adding any physical configuration.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example, the material of the damping member 70 may be different from that of the conveying belts B1 and B2. However, such a different material has the same damping characteristics as the conveying belts B1 and B2.

The damping member 70 may be provided outside the housing 9 (lower part 9c).

A damping member having a trapezoidal cross section perpendicular to the transport direction A may be provided below the gap C. The trapezoidal damping member 70 equalizes the amount of X-rays received that reach the X-ray detection unit 7 when a carbon member is built into the first transport unit 51 and the second transport unit 52.

The first conveying section 51 and the second conveying section 52 (the first conveying surface 51a and the second conveying surface 52a) may extend horizontally without being inclined with respect to the horizontal plane. In other words, the first conveying section 51 and the second conveying section 52 may be flat conveyors spaced apart in the width direction, rather than V-shaped conveyors.

1...X-ray inspection device, 4...inspection room, 4a...entrance opening, 4b...exit opening, 5...transport unit, 6...X-ray irradiation unit, 7...X-ray detection unit, 9...housing, 10...control unit, 15...inspection unit, 21...first frame (conveyor frame), 22...second frame (conveyor frame), 31...first frame (conveyor frame), 32...second frame (conveyor frame), 51...first transport unit, 51a...first transport surface, 52...second transport unit, 52a...second transport surface, 60...connecting member, 69...air nozzle, 70...damping member (damping section), 71...signal acquisition unit, 72...reduction processing unit (damping section), 73...image generation unit, 74...determination unit, 91...first wall portion, 92...second wall portion, 93...third wall portion, A...transport direction, B1...first transport belt, B2...second transport belt, C...gap, G...item, X...passage area.

Claims (5)

a conveying unit that conveys an article in a conveying direction, the conveying unit having a first conveying section and a second conveying section that are arranged spaced apart in a horizontal direction perpendicular to the conveying direction, the conveying unit supporting and conveying an article straddling a first conveying surface of the first conveying section and a second conveying surface of the second conveying section;
an X-ray detection unit that detects, among the X-rays irradiated to the object, first X-rays that have passed through the object without passing through either the first transport unit or the second transport unit, and second X-rays that have passed through both the object and either the first transport unit or the second transport unit;
an inspection unit that inspects the article based on a detection signal from the X-ray detection unit;
an attenuation unit that imparts, to either the first X-rays or a first detection signal corresponding to the first X-rays, attenuation characteristics equivalent to attenuation characteristics of the first X-rays transmitted through either the first transport unit or the second transport unit;
An X-ray inspection apparatus comprising: The X-ray inspection device according to claim 1, wherein the attenuation unit is an attenuation member that is arranged in a region connecting the X-ray irradiation unit and the contour of the gap between the first transport unit and the second transport unit and attenuates the first X-ray. The X-ray detector further includes a housing that houses the X-ray detection unit.
The X-ray inspection apparatus of claim 2 , wherein the attenuating member is disposed within the housing. The X-ray inspection device according to claim 3, further comprising an air nozzle that sprays air toward the upper surface of the housing that intersects vertically with the attenuation member. The inspection unit includes:
a signal acquiring unit for acquiring a detection signal from the X-ray detection unit;
a reduction processing unit that reduces only a detection value of the first detection signal among the detection signals;
2. The X-ray inspection device according to claim 1, further comprising: an image generating unit that generates an X-ray transmission image of the item based on the first detection signal that has been subjected to reduction processing in the reduction processing unit and a second detection signal corresponding to the second X-ray.

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