JP7407877B2 - X-ray inspection equipment - Google Patents

Description

The present invention performs an inspection by irradiating an object to be inspected that is transported inside a housing while being guided by a guide member. The present invention relates to an X-ray inspection apparatus equipped with a detection sensor, and particularly to an X-ray inspection apparatus that achieves both safety for users and stable transportation unaffected by the height of an object to be inspected.

Patent Document 1 listed below discloses an invention of an X-ray foreign object detection device. According to this X-ray foreign object detection device, a light emitting/receiving element 4 is provided at the height of an inlet and an outlet, and the light emitting/receiving element 4 detects whether or not an object passes through the monitoring area. be able to. When an object is detected, the control means determines whether the object is a human body or the object to be inspected W based on the level of the detection signal, and if it is determined to be a human body, the control means reduces the X-ray exposure amount to less than a predetermined amount. control. The human body can be protected from X-ray exposure by detecting the intrusion of the human body into the transport path and controlling the amount of X-ray exposure.

Patent Document 2 listed below discloses an invention of an X-ray inspection apparatus characterized in that the positions of an X-ray generator and an X-ray detector incorporated into a transport path can be easily adjusted. In this X-ray inspection device, two continuous rod-shaped guide members on the left and right sides pass through the openings 7 and 8 of the housing 4 in order to guide the inspected object being transported inside the housing. placed at the same height.

Japanese Patent Application Publication No. 2018-116001

2. Description of the Related Art X-ray inspection apparatuses are widely used to perform inspection by irradiating X-rays at a predetermined position while transporting an object to be inspected within a housing with a shielding structure, for the purpose of discovering foreign substances in an object to be inspected. In such an X-ray inspection apparatus , in order to stably transport the object to be inspected without overturning it and bring it to the inspection position in a predetermined posture, the height of the object to be inspected is adjusted as shown in Patent Document 1 mentioned above. A rod-shaped guide member corresponding to the size of the housing may be provided to pass through the entrance/exit of the housing.

In an X-ray inspection apparatus equipped with such a guide member, when a paper-packed product such as milk or alcohol is to be inspected, the following problems arise. Paper pack products such as milk and alcoholic beverages are generally available in multiple types of paper packs with the same bottom shape but different heights, and the paper pack is selected and manufactured according to the type (capacity) of the required product. Therefore, it is common for multiple types of objects to be inspected with different heights to be transported on the inspection line, and X-ray inspection equipment had to be able to handle multiple types of objects to be inspected with different heights. .

For this reason, in the above-mentioned X-ray inspection apparatus, a bar-shaped guide member corresponding to the height of the object to be inspected passes through the entrance and exit of the housing, and extends between the entrance and the outlet so as to sandwich the object to be inspected. They are provided on the left and right sides of the exit, and in particular, the number of guide rods installed and their arrangement must be such that the object to be inspected can be guided stably regardless of its height. Generally, as shown in Patent Document 1 , there must be at least two on each side, with at least one placed to suit tall products, and at least the other placed to suit short products. It is necessary to have a suitable layout. Even if the X-ray inspection device is equipped with a plate-shaped guide member that hardly attenuates X-rays, if the part to be inspected protrudes significantly upwards than the guide member, the X-rays may pass through the object to be inspected. The degree of attenuation of the X-rays received from the guide member differs depending on the position at which the X-rays that have reached the X-ray detection means have passed through the object to be inspected. In some areas, streak-like shading edges appear on the generated transparent image. Therefore, unless the data obtained from the X-ray detection means is appropriately corrected so as to eliminate the shading edges that appear on the transmitted image, the results of the transmitted inspection of the object to be inspected cannot be properly evaluated.

The present invention has been made in view of the conventional technology and its problems described above , and it is possible to provide a guide member of an object to be inspected in such a way that the detection results by the X-ray detection means are substantially the same for all positions of the object to be inspected. It is an object of the present invention to provide an X-ray inspection apparatus that can achieve stable transportation and improve inspection accuracy.

The X-ray inspection apparatus 1 according to claim 1 includes:
A housing 2 having a shielding structure and provided with an inlet 6 and an outlet 7 for the inspected object W;
X-ray irradiation means 4 that irradiates X-rays from the lateral direction onto the inspection object W that is transported by the transport means 3 inside the housing 2 along the transport direction C from the entrance 6 toward the exit 7;
X-ray detection means 5 for detecting X-rays transmitted through the inspection object W;
An X-ray inspection apparatus 1 having :
A continuous longitudinal plate made of a material that easily transmits the X-rays irradiated by the X-ray irradiation means 4, and guides the inspection object W transported by the transport means 3 from the entrance 6 to the exit 7 . It has guide members 15 and 16,
The heights of the guide members 15 and 16 are set so that the X-rays that have passed through the inspection object W and reached the X-ray detection means 5 are transmitted through the guide members 15 and 16. There is.

According to the X-ray inspection apparatus according to claim 1,
The height of the guide member is set so that the X-rays that have passed through the object to be inspected and reached the X-ray detection means also pass through the guide member. Therefore, the conditions under which the guide attenuates the X-rays are substantially the same and do not vary at all positions within the height range of the object to be inspected, so that the X-rays that have passed through the object and reached the X-ray detection means Unlike the case where there is a portion of the line that does not pass through the guide member, there is no need to correct the detection result.

1 is a perspective view of a part of an X-ray inspection apparatus according to an embodiment of the present invention, seen from the front side; FIG. 2 is a right side view showing the configuration near the entrance of the casing of the X-ray inspection apparatus according to the embodiment. FIG. 2 is a schematic diagram of a first example of the X-ray inspection apparatus according to the embodiment, showing the configuration near the inspection position in the housing and the positional relationship between the X-ray irradiation range and the object to be inspected from the right side direction. In the X-ray inspection apparatus of the embodiment, it is a schematic diagram of a second example showing the configuration near the inspection position in the housing and the positional relationship between the X-ray irradiation range and the object to be inspected from the right side direction.

A first embodiment of the present invention will be described with reference to FIGS. 1 to 4.
First, the configuration of the X-ray inspection apparatus 1 of this embodiment will be explained with reference to FIGS. 1 to 3.
As shown in FIG. 1, the X-ray inspection apparatus 1 of this embodiment includes a housing 2 having an X-ray shielding structure in which an inlet 6 and an outlet 7 are provided, and both ends of which are exposed from the openings of the inlet 6 and outlet 7. A conveyor 3 is provided inside the casing 2 so as to protrude, and serves as a conveying means for conveying the inspected object W along a predetermined conveying direction C inside the casing 2 including the inspection area P; The apparatus includes an X-ray irradiation means 4 for irradiating X-rays in an inspection area P onto an object W to be inspected, which is conveyed by the object W to be inspected. Note that the inspection area P is provided inside the casing 2 at a position intermediate between the entrance 6 and the exit 7. The entirety of the X-ray inspection apparatus 1 described above is installed on a platform surface by means of legs 8.

In FIGS. 1 and 3, the X-ray irradiation means 4 is schematically shown as a point or a circle indicating the position of the anode target where X-rays are generated. 3. X-rays are irradiated on the object W to be inspected from the lateral direction. Further, the X-ray detection means 5 is arranged on the opposite side of the X-ray irradiation means 4 across the inspection object W in the inspection area P, and is constituted by a line sensor in which a plurality of detection elements 5a are arranged vertically. ing.

Furthermore, although not shown, a carry-in conveyor is provided upstream of the conveyor 3, and is configured to supply the object W to be inspected sent from upstream to the X-ray inspection apparatus 1. Further, an unloading conveyor is provided on the downstream side of the conveyor 3, and is configured to carry out the inspected object W from the X-ray inspection apparatus 1 and send it to the next process (for example, a sorting process) on the downstream side. has been done.

As schematically shown in FIG. 1, the openings of the inlet 6 and outlet 7 of the casing 2 contain foreign objects other than the object W to be inspected, such as a user's hand, which passes through the openings at the conveyance speed of the conveyor 3. A detection sensor 10 is provided in order to detect that the object is erroneously present in the opening.

As shown in FIG. 2, the detection sensor 10 is a retroreflection type photoelectric sensor, and includes a light emitting/receiving section 11 that emits and receives beam-shaped light, and a light emitting/receiving section that reflects the light from the light emitting/receiving section 11. If some object enters between the light emitting/receiving part 11 and the reflecting part 12 and the optical path continues to be blocked beyond the time required for the inspection object W to pass through the aperture, A control section (not shown) is configured to generate a detection signal indicating the presence of a foreign object. Note that the detection sensor 10 may be a transmission type photoelectric sensor that includes a light projecting section that emits a beam of light and a light receiving section that receives the light from the light projecting section.

As shown in FIG. 2, in this embodiment, five detection sensors 10 are provided at the inlet 6 and five at the outlet 7. The detection sensors 10 are arranged so that each optical path is horizontal within the opening of the entrance 6 and at predetermined intervals in the vertical direction. The outlet 7 has a similar arrangement. Specifically, if the opening height of the inlet 6 and the outlet 7 is H with respect to the conveyance surface S of the conveyor 3, the detection sensor 10 located at the top has a height of (0.9× The lowest detection sensor 10 provided at position H) is also provided at a position of (0.1 x H) with respect to the conveyance surface S, with an interval of (0.2 x H) between them. There are three of them. Note that the opening height H, which corresponds to the height of a milk carton with a capacity of 1000 ml, is preferably about 24 cm to 25 cm.

As shown in FIGS. 1 and 2, a pair of guide members 15, 15 for guiding the inspection object W conveyed by the conveyor 3 are arranged facing each other along the conveyor 3. Each of the pair of guide members 15, 15 has a continuous longitudinal plate shape, and is preferably arranged seamlessly over a length equivalent to the conveyor 3. A pair of guide members 15, 15 move the object W to be inspected which is above the transport conveyor 3 and on the transport surface S with a small gap between them and the transport surface S so that they do not come into contact with each other. They are arranged parallel to each other at positions on both sides of the inspection object, with an attitude parallel to the conveyance direction C and the vertical direction, with an interval that does not make sliding contact with the object to be inspected. The pair of guide members 15, 15 are attached to the frames 3a, 3a of the conveyor 3.

The guide member 15 is made of a material that easily transmits the light irradiated by the detection sensor 10 and the X-rays irradiated by the X-ray irradiation means 4. Examples of materials that can be used include resin plates such as PET, acrylic, and polycarbonate. The thickness of the guide member 15 is such that it can maintain the strength necessary to guide the moving inspected object W, has a weight that can be attached to the frames 3a, 3a of the conveyor 3, and has a weight that allows it to be attached to the frames 3a, 3a of the conveyor 3. 10 and the X-ray detection means 5 can perform the necessary functions, and the thickness is such that the intensity of the transmitted light and X-rays is not weakened. For example, it is only necessary to ensure a light transmittance of 50% or more and an X-ray transmittance of 80% or more in the detection sensor 10, and various functions such as image processing can be operated correctly under these initial conditions. Parameters for this are set in the X-ray inspection equipment.

Note that the conveyance direction C by the conveyor 3 is indicated by an arrow in FIG. 1, and is a direction perpendicular to the paper surface in other figures. Further, as shown in FIG. 1, the width of the conveyor 3 at the entrance 6 and the exit 7 is slightly smaller than the distance between the pair of guide members 15, 15, but as shown in FIG. In the vicinity of the inspection area P, the width of the base 13, which is integral with the frame 3a of the conveyor 3, is wider than the distance between the pair of guide members 15.

As shown in FIG. 2, the height of the guide member 15 is set higher than the tallest product among the objects W to be inspected that are assumed to be inspected by this X-ray inspection apparatus 1. Specifically, for example, if a milk paper carton product is the inspection object W, there are two types of milk paper carton products, 500 ml and 1000 ml, which have the same bottom shape but different heights and capacities. As is known, the height of the guide member 15 of this X-ray inspection apparatus 1 is set larger than the height of a tall product.

The reason why the height of the guide member 15 is set higher than the tallest product will be explained with reference to FIG. 3. As described above with reference to FIG. 1, as shown in FIG. 3, in this X-ray inspection apparatus 1, X-rays are emitted in a lateral direction ( The X-rays transmitted through the object W to be inspected are detected by the X-ray detection means 5 located on the other side of the object W to be inspected. Here, since all the X-rays that have passed through the object W to be inspected and reached the X-ray detection means 5 have also passed through the two guide members 15, members other than the object W to be inspected (i.e., the guide members 15 ) is at most a slight attenuation of the X-rays when the X-rays pass through the guide member 15 in the thickness direction, and is generated based on data obtained from each detection element 5a of the X-ray detection means 5. Although the transmitted image appears as a continuously gently changing offset, there are no shading differences or shading edges that are inconvenient for X-ray inspection, and once sensitivity correction is performed to correct variations in each detection element 5a, it can be corrected again. There is no need to do so.

Here, suppose that the height of the two guide members 15 is set to a height such that the upper part of the object W to be inspected is exposed (for example, the top of the guide member 15 is set 2/2/2 from the bottom of the object W to be inspected. 3). Although it is possible to ensure the stability of the inspected object W during transportation, the X-rays that have passed through the inspected object W and reached the X-ray detection means 5 are The degree of attenuation of the X-rays received from the guide member 15 differs depending on the location. That is, among the X-rays that have passed through the object W to be inspected and reached the X-ray detection means 5, the X-rays that have passed through the lower part of the object W have passed through the two guide members 15; The X-rays that have passed through the upper part only pass through the guide member 15 on the side of the X-ray irradiation means 4, and the X-rays that have passed through the upper part do not pass through the guide member 15 at all and are detected as X-rays. Means 5 has been reached. In this way, even with the guide member 15 that hardly attenuates X-rays, a streak-like shading edge appears on the generated transmitted image at the portion corresponding to the end (in this case, the upper end). The portion where this dark and light edge appears changes due to vibrations caused by the contact of the inspection object W with the guide member 15 or the operation of the conveyor 3.

Therefore, if the guide member 15 is low as described above and the object W to be inspected protrudes above the guide member 15 to a large extent, the data obtained from each detection element 5a of the X-ray detection means 5 is corrected as appropriate. , it is not possible to properly evaluate the results of the transmission inspection of the object W to be inspected unless correction is made to eliminate the shading edges that appear on the transmission image.

However, according to the X-ray inspection apparatus 1 of this embodiment, all the X-rays that have passed through the object W to be inspected and reached the X-ray detection means 5 have passed through the two guide members 15. Since the conditions for attenuating the rays are substantially the same and do not vary, there is no need to correct the data obtained from each detection element 5a of the X-ray detection means 5, and data calculation in the control means can be performed relatively easily. In addition, if the height of the guide member 15 is set to be larger than the tallest of the expected multiple types of objects to be inspected, both tall and short products can be stably guided. Effects can also be obtained.

Next, the operation of the X-ray inspection apparatus 1 of this embodiment will be explained with reference to FIGS. 1 to 3.
As described above, this X-ray inspection apparatus 1 is capable of handling both relatively tall objects W to be inspected and relatively short objects W to be inspected. Among the products, a relatively tall one is defined as an object to be inspected W, and an inspection process for inspecting this will be explained.

In FIG. 1, an object W to be inspected is sent to a transport conveyor 3 by an upstream transport conveyor (not shown) on the upstream side (right side in the figure). As shown in FIG. 2, the pair of guide members 15, 15 on both sides of the conveyor 3 are arranged parallel to each other at intervals higher than the height of the object W to be inspected and slightly larger than the width of the object W to be inspected. ing. For this reason, even though the inspected object W is relatively tall and easily falls over, it remains stable during transportation in a predetermined inspection posture determined when it is loaded onto the conveyor, and may tilt, fall over, or shift position during transportation. It is sent to the shielded inspection area P in the center of the housing 2 without any problem.

While the X-ray inspection apparatus 1 is in operation, the detection sensor 10 is also constantly in operation. Although the guide member 15 is located in the middle of the optical path of the detection sensor 10, the light from the detection sensor 10 passes through the guide member 15, which is made of a material that easily transmits light, without being obstructed, and the amount of transmitted light is sufficient for detection. It is a value. Therefore, there is no problem with the detection conditions when the optical path is blocked by a foreign object other than the object W to be inspected, and the ability to detect foreign objects is stable. Therefore, even if a user using the device 1 accidentally inserts his or her hand through the entrance 6 or exit 7, the detection sensor 10 will detect this and receive the output from the detection sensor 10. The control means immediately stops the operation of the X-ray irradiation means 4 and provides necessary notification by means of an alarm sound or light. This ensures appropriate safety.

Furthermore, since the guide member 15 is made of a material that easily transmits the light emitted by the detection sensor 10, there is no need to consider the arrangement of the guide member 15 when arranging the detection sensor 10, and the number, position, etc. The direction of the optical path, etc. can be optimally set considering only effective detection of foreign objects. For example, the number of detection sensors 10 may be increased or decreased from the five shown in FIG. 2, the optical paths may be diagonal instead of horizontal, or they may not be parallel to each other but may intersect with each other. If the guide member is a rod-shaped guide member as described in "Background Art", it will be necessary to arrange the optical path so as to avoid this, and the arrangement of the detection sensor 10 will be restricted.

The object W to be inspected is conveyed by the conveyor 3, enters the center of the inspection area P covered by the housing 2, and is irradiated with X-rays from the X-ray irradiation means 4. The X-rays that have passed through the object W to be inspected are detected by each detection element 5a of the X-ray detection means 5. The control means inspects whether the object W to be inspected contains foreign matter based on the output of the X-ray detection means 5.

In this inspection process, all the X-rays that have passed through the object W to be inspected and reached the X-ray detection means 5 have passed through the two guide members 15, and the detection results by the X-ray detection means 5 are All positions of the inspection object W are obtained under substantially the same conditions. Therefore, there is no need to correct the data obtained from each detection element 5a of the X-ray detection means 5, and data calculation in the control means is relatively simple. Note that since the guide member 15 is made of a material that easily transmits the X-rays irradiated by the X-ray irradiation means 4, there is no need to consider the possibility that the attenuation of the X-rays will affect the inspection. If the guide member is rod-shaped as explained in "Background Art", some of the X-rays that have passed through the object W to be inspected may have passed through the guide member, and some may not have passed through the guide member. The number of guide members that have passed through may vary, and these various conditions will coexist. Therefore, the data output by each detection element of the X-ray detection means is not obtained under substantially the same conditions, and complex correction calculations are required.

The inspected object W is conveyed by the conveyor 3 and exits the housing 2 through the exit 7. Thereafter, the inspected object W that has been inspected is sent to the next downstream process (for example, a sorting process) by a transport conveyor (not shown).

Next, a modification of the embodiment in which the structure of the guide member 15 is different will be described with reference to FIG. 4.
In the modification shown in FIG. 4, in order to constantize the conditions for X-rays to pass through the guide member, only the guide member 15 on the side of the X-ray detection means 5 is made higher than the object W to be inspected, and the X-rays are irradiated. The height of the guide member 16 on the side of the means 4 was set to be the same as or slightly smaller than the object W to be inspected. Even in this case, the X-rays that pass through the object W to be inspected and reach the X-ray detection means 5 also pass through the two guide members 15 and 16, and the X-rays are obtained from each detection element 5a of the X-ray detection means 5. There is no need to correct the data.

In this modification, only in the inspection area P, the guide member 15 on the side of the X-ray detection means 5 is made higher than the inspected object W, and in the area other than the inspection area P, the guide member 15 of the two guide members The heights of all the test pieces were set to a relatively low dimension (the height of the guide member 16) equivalent to that of the object W to be inspected. In this way, even though the inspected object W is sandwiched between the pair of guide members 15 and 16, the top part of the inspected object W can be easily accessed. This is advantageous when it is desired to take W out of the guide members 15 and 16. Further, since the heights of the entrance 6 and the exit 7 of the housing 2 can be made low in accordance with the relatively low height of the guide member 16, it becomes more advantageous in terms of shielding X-rays from the outside.

DESCRIPTION OF SYMBOLS 1... X-ray inspection device 2... Housing 3... Conveyor as a conveyance means 4... X-ray irradiation means 5... X-ray detection means 5a... Detection element 6... Inlet 7... Exit 10... Detection sensor 15... Guide member 16... Guide member W...Object to be inspected C...Transportation direction S...Transportation surface P...Inspection area

Claims (1)

a housing (2) with a shielding structure provided with an entrance (6) and an exit (7) for the object to be inspected (W);
X-ray irradiation means (4) for laterally irradiating an object to be inspected that is transported by the transport means (3) inside the housing along the transport direction (C) from the entrance toward the exit; and,
X-ray detection means (5) for detecting X-rays that have passed through the inspection object;
An X-ray inspection device (1) having
A continuous longitudinal plate-shaped guide member (15 , 16),
X-ray inspection apparatus (1) characterized in that the height of the guide member is set so that the X-rays that have passed through the object to be inspected and reached the X-ray detection means are transmitted through the guide member. .