JP4108657B2 - X-ray foreign object detection device - Google Patents

Description

  The present invention relates to an X-ray foreign matter detection apparatus that performs an inspection (hereinafter referred to as a foreign matter mixing inspection) for detecting foreign matters mixed in an article by conveying an article and irradiating it with X-rays.

  2. Description of the Related Art In a production line for foods and the like, an X-ray foreign matter detection device that uses X-rays to inspect foreign matter contamination for products is used. Here, the X-ray foreign matter detection apparatus irradiates an inspection target article (hereinafter referred to as an inspection object) conveyed using a conveyor or the like and transmits X-rays that pass through the inspection object. The amount is measured, and it is determined whether or not foreign matter is mixed (hereinafter referred to as foreign matter mixing determination) based on the measured transmission amount information.

  Here, examples of the foreign matter to be detected by the X-ray foreign matter detection apparatus include bones such as metal and fish, stones, glass, and plastics. Since the foreign objects to be detected by the X-ray foreign object detection device include those that are not detected by the metal detection device, the X-ray foreign object detection device is effective for the foreign object contamination inspection. When the type of foreign matter to be detected is different, the foreign matter detection sensitivity is generally different. Therefore, in order to make it easier to detect foreign matter, mask X-ray transmission amount, X-ray intensity, threshold for foreign matter determination, and objects intentionally added to the inspection object prior to foreign matter inspection. Various parameters such as the mask area are set.

  The operator carried the object to be inspected on the conveyor a plurality of times, and set each of the above parameters in sequence using the automatic setting function of the X-ray foreign object detection device. Regarding the metal detection device, a technique for setting each parameter by repeating the inversion of the conveyor without carrying the inspection object has been disclosed in consideration of the heavy inspection object and the burden on the operator ( For example, see Patent Document 1.) Similarly, a technique for reversing a conveyor has been disclosed in recent years for an X-ray foreign matter detection apparatus (see, for example, Patent Document 2).

Since the X-ray foreign matter detection apparatus performs foreign matter mixing inspection using X-rays, the dose of X-rays leaked to the outside must be less than or equal to a reference value stipulated by law. Here, according to the law, the dose of X-rays allowed to leak is specified by the exposure amount (unit is Sv), and the total exposure amount is 1.3 mSv or less for 3 months. For this reason, in the X-ray foreign object detection device that has a short machine length in the conveyance direction and may leak X-rays from the conveyance port of the device, the shielding curtain is suspended in the conveyance path inside the device and irradiated from the X-ray generator. X-rays are prevented from leaking outside the X-ray foreign object detection device.
Japanese Utility Model Publication No. 1-78978 JP 2002-148212 A

  However, in such a conventional X-ray foreign object detection device, when performing parameter setting that involves reversing the conveying direction of the conveyor, the object to be inspected on the conveyor does not shield the shielding curtain during the reversing operation that reverses the conveying direction of the conveyor. There is a problem that the X-ray may leak outside the X-ray foreign object detection device because it stops in the open state. Here, as described above, it is very important from the viewpoint of ensuring the safety of the operator that X-rays are not leaked to the outside from the X-ray foreign matter detection apparatus.

  The present invention has been made to solve such a problem, and an X-ray foreign object detection device capable of preventing X-rays from leaking outside from the X-ray foreign object detection device in automatic setting of parameters for defining inspection conditions. Is to provide.

Considering the above points, the invention according to claim 1 is an X-ray for inspecting whether or not foreign matter is mixed in the inspection object by irradiating the inspection object (1) with X-rays. A foreign matter detection device (100), a transport unit (110) for transporting the object to be inspected, an X-ray generator (120) for generating X-rays to be irradiated to the object to be inspected transported by the transport unit, An X-ray line sensor (130) that senses the amount of X-ray transmitted through the inspection object among the X-rays irradiated to the inspection object, and a conveyance path through which the conveyance unit conveys the inspection object A housing that covers at least a part of the X-ray generator and accommodates the X-ray generator and the X-ray line sensor, and has an inlet and an outlet for transporting the inspection object, Provided above the transport path, X-rays are emitted from the entrance and the exit An X-ray foreign matter detection apparatus comprising a plurality of shielding curtains for preventing leakage, a passage detection means for detecting that an inspection object has passed over the X-ray line sensor, and an inspection object to be inspected in advance A transport control means (144) for performing predetermined transport control including control for reversing the transport direction transported by the transport section when automatically setting a parameter for defining an inspection condition by repeatedly transporting the transport section by the transport section; , Stop conveyance of the inspection object in order to reverse the conveyance direction at a position where at least one of the shielding curtains located in front of the X-ray line sensor in the conveyance direction cannot be opened by the inspection object the passing detection hand that a storage means for storing a target position, the transfer control means, said object to be inspected passes over the X-ray line sensor when the There after detecting, and has a structure for controlling the conveyance to stop the inspection object to the target position stored in the storage means.

With this configuration, the transport control means, in the automatic setting of the parameters defining the test conditions, when the conveyance direction conveying is stopped in order to reverse, the shielding curtain is located in the conveying direction forward with respect to the X-ray line sensor Since conveyance control is performed so that at least one is not opened by the object to be inspected, X-rays can be prevented from leaking outside from the X-ray foreign object detection device during parameter setting operations, thus ensuring worker safety. It is possible to realize an X-ray foreign object detection device that can do this.

According to a second aspect of the present invention, in the first aspect, the storage unit further stores time change data of a conveyance speed, and the conveyance control unit is configured such that the inspection object is the X-ray line sensor. A configuration in which the conveyance control is performed so that the inspection object is stopped based on the target position and the time change data of the conveyance speed stored in the storage unit after the passage detection unit detects that the vehicle has passed above. have.

With this configuration, in addition to the effect of the first aspect, after the passage detection unit detects that the inspection object has passed over the X-ray line sensor , the conveyance control unit detects the target position and the conveyance speed stored in the storage unit. Since the conveyance control is performed so as to stop the inspection object based on the time change data, the time required for the conveyance control for stopping the inspection object can be lengthened, and the inspection object can be stopped at the target position. An X-ray foreign object detection device that can be easily realized can be realized.

According to a third aspect of the present invention, in the first aspect of the present invention, the storage means further stores a braking distance necessary to stop the conveyance, and the conveyance control means is configured such that the inspection object includes the inspection object. A configuration in which conveyance control is performed to stop the inspection object based on the target position and the braking distance stored in the storage unit after the passage detection unit detects that the X-ray line sensor has passed. have.

With this configuration, it is possible to realize an X-ray foreign object detection device capable of easily stopping the inspection object at the target position.

According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention , the monitoring area in the vicinity of the nearest shielding curtain located forward in the transport direction with respect to the X-ray line sensor. It comprises arrival detection means for detecting that the inspection object has arrived, and the conveyance control means stops conveyance when the arrival detection means detects that the inspection object has reached the monitoring area. In this way, the conveyance control is performed.

  With this configuration, in addition to the effects of any one of claims 1 to 3, in the automatic setting of the parameters that define the inspection conditions, the arrival detection means detects that the inspection object has reached the monitoring area. X-ray foreign object detection that can prevent X-rays from leaking because the object to be inspected opens the external shielding curtain because the conveyance control means performs conveyance control to stop conveyance An apparatus can be realized.

  According to the present invention, in the automatic setting of the parameters that define the inspection conditions, the conveyance control unit reduces the conveyance speed within a predetermined time after the passage detection unit detects that the inspection object has passed over the X-ray line sensor. When the conveyance is stopped because the conveyance direction is reversed, the conveyance control is performed so that at least one of the shielding curtains positioned in front of the X-ray line sensor in the conveyance direction is not opened by the inspection object. Therefore, it is possible to provide an X-ray foreign object detection device that can prevent X-rays from leaking from the X-ray foreign object detection device to the outside during the parameter setting operation, thereby ensuring the safety of the operator. Is.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment)
FIG. 1 is an explanatory diagram conceptually showing a block configuration of an X-ray foreign object detection device according to an embodiment of the present invention. An X-ray foreign object detection apparatus 100 according to an embodiment of the present invention includes a transport unit 110 that transports an object to be inspected 1 and an X-ray generator that generates X-rays that irradiate the test object 1 that the transport unit 110 transports. 120, an X-ray line sensor 130 for sensing the amount of X-rays transmitted through the inspection object 1 (hereinafter referred to as transmission X-rays) among the X-rays irradiated to the inspection object 1, and an X-ray line Information regarding the transmission amount of transmitted X-rays output from the sensor 130 is processed to determine whether or not foreign matter is mixed in the inspection object (hereinafter referred to as foreign matter mixing determination), and the conveyance unit 110 and A control processing unit 140 that controls the X-ray generator 120 and a display unit 150 that displays information output from the control processing unit 140 are provided.

  The conveyance unit 110 is configured to include a conveyance belt 111, a roller 112, and a conveyance driving unit 113 such as a motor unit. Two rollers 112 are arranged at the front and rear portions in the transport direction, respectively, and these have a predetermined height in the height direction. The conveyor belt 111 is endless and is wound around a roller 112. The conveyance driving unit 113 is connected to one of the rollers 112 and rotationally drives the roller 112. The transport belt 111 is made of a material that is easy to transmit X-rays and is made of an element other than an element having a large atomic weight.

  The X-ray foreign object detection device 100 further includes a housing 20 that prevents X-rays from leaking to the outside as shown in FIG. FIG. 2 is a perspective view showing an example of the X-ray foreign object detection apparatus 100 according to the embodiment of the present invention. The case 20 includes a radiation source front panel 21 that is opened when handling the transfer unit 110 and the like stored in the case 20, and a transfer unit that is opened when handling the X-ray line sensor 130, the transfer unit 110, and the like. The front panel 22, the rear panel 23 provided on the surface facing the radiation source front panel 21 or the transport unit front panel 22, and parts other than the radiation source front panel 21, the transport unit front panel 22 and the rear panel 23 (for example, The outer side surface portion of the X-ray foreign object detection device 100, etc.).

  The X-ray generator 120 is stored in a space surrounded by the radiation source front panel 21 and the fixing unit 24. Part or all of the transport unit 110 and the X-ray line sensor 130 are stored in a space surrounded by the transport unit front panel 22 and the fixed unit 24. Further, a transport port 221 (consisting of an inlet 221 a and an outlet 221 b) for transporting the inspection object 1 into the X-ray foreign object detection device 100 is provided between the transport unit front panel 22 and the fixed unit 24. ing.

  The transport unit front panel 22 is pivotally supported by a hinge 222 provided at the lower portion of the fixed unit 24, and is configured to be openable to the front side (the front side in the Y-axis direction shown in FIG. 2). The housing 20 is made of a material that hardly transmits X-rays such as metal so that X-rays generated by the X-ray generator 120 do not leak to the outside from portions other than the inlet 221a and the outlet 221b.

  FIG. 3 is a cross-sectional view of the X-ray foreign object detection device 100 on a surface parallel to the surface of the conveyor belt 111 on the surface of the conveyor belt 111. The X-ray foreign object detection apparatus 100 receives the inspection object 1 conveyed from the outside in the X-axis direction via the conveyance port 221 (inlet 221a) and discharges it to the outside from the other conveyance port 221 (outlet 221b). It is like that. However, as will be described later, when the parameters for defining the inspection conditions (hereinafter referred to as inspection condition defining parameters) are automatically set, the inspection object 1 is not moved in and out through the transport port 221. .

  FIG. 4 is a cross-sectional view along the conveyance direction for conceptually explaining the configuration in the vicinity of the space in which the inspection object 1 in the housing 20 is conveyed. As shown in FIGS. 3 and 4, a plurality of shielding curtains 11 and 12 that prevent X-rays from leaking from the entrance 221 a and the exit 221 b are provided on the conveyance path in the housing 20. Here, the shielding curtain 11 is provided suspended from the housing 20 so as to close the inlet 221a and the outlet 221b of the housing 20.

  On the other hand, the shielding curtain 12 is provided between the shielding curtain 11 and the X-ray line sensor 130. Here, between the shielding curtain closest to the X-ray line sensor 130 (or the X-ray generator 120) and the X-ray line sensor 130, is X-rays irradiated and foreign matter mixed in the inspection object 1? A predetermined distance is ensured so that the conveyance speed of the inspection object 1 can be appropriately ensured when the foreign matter mixing inspection is performed.

  Hereinafter, the space on the conveyance path in the housing 20 partitioned by the two shielding curtains 11 is referred to as a conveyance space, and the nearest shielding curtain of the X-ray line sensor 130 (or the X-ray generator 120) in the conveyance space. A space partitioned by 12 is called a detection space. Specifically, the shielding curtains 11 and 12 are provided to be suspended from the housing 20 in the conveyance space excluding the detection space.

  As shown in FIG. 4, the X-ray generator 120 is generated by a cylindrical X-ray tube 121 that generates X-rays by colliding electrons accelerated by applying a voltage with a target, and an X-ray tube 121. And an irradiation slit 122 for irradiating X-rays toward the X-ray line sensor 130. Hereinafter, the voltage for accelerating electrons to collide with the target is referred to as acceleration voltage.

  The X-ray tube 121 is cooled, for example, immersed in an insulating oil held inside a metal box. The X-ray tube 121 is also provided so that its longitudinal direction is orthogonal to the conveyance direction of the inspection object 1 (X-axis direction shown in FIG. 2). The X-rays generated by the X-ray tube 121 are directed toward the X-ray line sensor 130 through the irradiation slit 122 along the longitudinal direction of the X-ray tube 121, and the substantially conical X-rays are converted into a substantially triangular screen. It comes to irradiate in the shape.

  Further, as shown in FIG. 4, in the vicinity of the X-ray line sensor 130, passage detection means 114 that detects that the inspection object 1 has passed over the X-ray line sensor 130 is provided. When the passage detection unit 114 detects that the inspection object 1 has passed over the X-ray line sensor 130, the passage detection unit 114 determines a passage detection signal indicating that the inspection object 1 has passed over the X-ray line sensor 130. To output.

  The X-ray line sensor 130 has a configuration in which the X-ray sensors are arranged in an array, and the transmitted X-rays that pass through the inspection object 1 conveyed on the X-ray line sensor 130 and reach the X-ray sensor. The amount is detected by each X-ray sensor constituting the array, and an electric signal corresponding to the detected transmission amount of the X-ray is output. Although not shown, the X-ray line sensor 130 is arranged in an array in, for example, a direction (Y-axis direction shown in FIG. 2) perpendicular to the conveyance direction of the inspection object 1 conveyed on the conveyance belt 111. An array line sensor including a plurality of photodiodes and a scintillator provided on the photodiode is used. The X-ray line sensor 130 is known and will not be described further.

  In the X-ray line sensor 130 having such a configuration, when the inspection object 1 is irradiated with X-rays from the X-ray generator 120, the X-ray transmitted through the inspection object 1 is received by the scintillator and converted into light. Convert. Further, the light converted by the scintillator is received by a photodiode disposed below the light. Each photodiode converts the received light into an electrical signal and outputs it to the control processing unit 140 as an array signal. Here, the array signal may be output to the control processing unit 140 after being converted into a digital signal.

  The passage detection unit 114 includes, for example, a light source that emits a light beam and a light receiver that receives the light beam emitted from the light source, and the light receiver cannot receive the light beam while the light source emits the light beam. It may be configured by a so-called projector / receiver that detects this and detects the entry of the article. The position where the light projector / receiver monitors the entry of the inspection object 1 is referred to as a monitoring position. When the light projector / receiver is used as the passage detection means 114, the signal generated by the light receiver is output to the control processing unit 140 as a passage detection signal. To do.

  Further, the light projecting / receiving device as the passage detection means 114 differentiates a signal generated when the light is received, and indicates a pulse signal (hereinafter referred to as a monitoring position) indicating that the inspection object 1 has entered the monitoring position of the passage detection means 114. And a pulse signal indicating that the vehicle has passed the monitoring position of the passage detection means 114 (hereinafter referred to as a monitoring position passage pulse signal) is output to the control processing unit 140 as the passage detection signal. Good.

  When a projector / receiver is used as the passage detection means 114 and the monitoring position is more than a predetermined value away from the position where the X-ray line sensor 130 is disposed, the inspection object 1 has passed over the X-ray line sensor 130 It is assumed that the control processing unit 140 performs predetermined signal processing. The detection that the inspection object 1 has passed over the X-ray line sensor 130 can be performed based on information on the conveyance speed and the distance between the monitoring position and the X-ray line sensor 130.

  Hereinafter, the “output signal from the light receiver”, the “monitoring position approach pulse signal”, and the “monitoring position passing pulse signal” are included in the “passing detection signal”, and a projector / receiver is used as the passage detecting means 114. The “output signal from the light receiver” will be described as the “passage detection signal”. Although FIG. 4 shows the case where the passage detection unit 114 is provided to monitor the left side of the X-ray line sensor 130, the X-ray line may be provided to monitor the X-ray line sensor 130. Whether it is provided so as to monitor the right side of the sensor 130 or so as to monitor both sides of the X-ray line sensor 130, other positions where the passage on the X-ray line sensor 130 can be detected are monitored. May be provided.

  Further, as shown in FIG. 4, a monitoring area in the vicinity of the nearest shielding curtain located in the front of the X-ray line sensor 130 in the conveyance direction (the direction indicated by the arrow in FIG. 4) is included in the housing 20. An arrival detection means 115 is provided for detecting that the inspection object has arrived. When the arrival detection means 115 detects that the inspection object 1 has reached the monitoring area, the arrival detection means 115 outputs an arrival detection signal indicating that the inspection object 1 has reached the monitoring area to the transport control means 144. Yes.

  The arrival detection means 115 may be configured by, for example, the above-described projector / receiver. In the above description, the example in which the arrival detection means 115 is provided at the position shown in FIG. 4 has been described. However, the arrival detection means 115 relates to the conveyance in the return direction (the direction opposite to the direction indicated by the arrow in FIG. 4). It may be provided at a position corresponding to the above position or at both monitoring positions. Furthermore, although the case where both the passage detection unit 114 and the arrival detection unit 115 are provided has been described above, either the passage detection unit 114 or the arrival detection unit 115 may not be provided.

  The control processing unit 140 includes an array signal that is information on the amount of transmitted X-rays from the X-ray line sensor 130, a passage detection signal from the passage detection unit 114, a arrival detection signal from the arrival detection unit 115, and an operation unit (not shown). Other signals such as an operation signal corresponding to the operation input from are input. The control processing unit 140 includes an image processing unit 141 that performs predetermined information processing such as image processing for generating a transmission image in the inspection object 1 based on the array signal input from the X-ray line sensor 130, and image processing. Judgment of foreign matter mixing based on the information of the transmission image output from the means 141, and determination of generating and outputting predetermined information necessary for control performed by the X-ray control means 143 and the conveyance control means 144 described later From the means 142, the X-ray control means 143 for controlling the X-ray generator 120 to generate X-rays or to stop the X-rays according to the signal output from the judging means 142, and the judging means 142 And a conveyance control unit 144 that controls the conveyance unit 110 in accordance with the output signal. Here, the control performed by the transport control unit 144 includes control for reversing the transport direction when the inspection condition defining parameter is automatically set.

  FIG. 5 is a diagram showing a block configuration of the control processing unit 140 constituting the X-ray foreign object detection device 100 according to the embodiment of the present invention. The control processing unit 140 includes an input interface 541 to which a predetermined signal is input, a CPU (Central Processing Unit) 542 that performs predetermined information processing and control for realizing the functions of the X-ray foreign object detection device 100, and a CPU 542. OS (Operating System) for starting up, ROM (Read Only Memory) 543 for storing other program and control condition defining parameters for control, etc., and execution codes and data of the OS and applications used by the CPU 542 for operation RAM (Random Access Memory) 544 and EEPROM (Electrically Erasable Programmable) that stores application software and predetermined data in a nonvolatile manner ROM) 545 and an output interface 546 for outputting a predetermined signal.

  In the above description, the configuration using the EEPROM 545 as the storage means for storing application software and predetermined data in a non-volatile manner has been described. However, the storage means is not limited to the EEPROM 545 and may be a hard disk or other non-volatile storage element. Good. Hereinafter, the term “EEPROM 545” means storage means for storing in a nonvolatile manner.

  Here, the input interface 541 includes an array signal from the X-ray line sensor 130, a passage detection signal from the passage detection unit 114, a arrival detection signal from the arrival detection unit 115, an operation signal from an operation unit (not shown), and the like. A signal is input. Other signals may include, for example, a mode designation signal for designating the operation mode of the X-ray foreign object detection device 100, a signal received by communication when performing predetermined control, and the like. The signal input to the input interface 541 is not limited to a digital signal, and includes an analog signal as necessary. In this case, the input interface 541 may include a configuration unit that converts an analog signal into a digital signal.

  Under the control of the CPU 542, the output interface 546 outputs a determination signal indicating the determination result of the foreign object mixing determination to an external device (not shown) such as a sorter. The output interface 546 outputs a transport control signal for controlling the transport unit 110 and other signals. Examples of the other signals include predetermined signals such as a signal for controlling the display unit 150 and the like and a signal transmitted by communication when performing the control. Further, the signal output from the output interface 546 is not limited to a digital signal, and includes an analog signal as necessary. In this case, the output interface 546 is assumed to have a configuration unit that converts a digital signal into an analog signal.

  The CPU 542 of the control processing unit 140 detects foreign matter based on an array signal input from the X-ray line sensor 130 via the input interface 541 when the X-ray generator 120 irradiates the inspection object 1 with X-rays. Mixing judgment is performed. The foreign substance contamination determination performed by the CPU 542 is based on the array signal input via the input interface 541 when the portion where the X-ray transmission amount is less than or equal to a preset threshold is detected. It is determined that foreign matter is mixed. In addition, said threshold value shall differ according to the kind of to-be-inspected object 1 and the foreign material mixed in to-be-inspected object 1. FIG. The determination of mixing of foreign matters is well known, and other detailed description is omitted.

  The CPU 542 also controls the transport unit 110 based on one of the detection signals of the passage detection signal and the arrival detection unit 115 input from the passage detection unit 114 in the automatic setting of the inspection condition defining parameter. A conveyance control signal is output to arrival detection means 115. Here, for convenience of explanation, the CPU 542 serving as the X-ray control unit 143 converts the X-rays to X-rays during the operation of automatically setting the inspection condition defining parameter when the operation mode for automatically setting the inspection condition defining parameter is designated. It is assumed that the X-ray generator 120 is controlled to irradiate the line sensor 130 and stop the irradiation except during the operation of automatically setting the inspection condition defining parameter. In addition, when performing the foreign matter contamination inspection, the X-ray generator 120 irradiates X-rays toward the X-ray line sensor 130 during the foreign matter contamination inspection operation and stops the irradiation except during the foreign matter contamination inspection operation. Shall be controlled.

  In addition, when the inspection condition defining parameter is automatically set, the CPU 542 generates a transmission image only in the same conveyance direction as the conveyance performed in the foreign matter mixing inspection, but the transmission is performed in each conveyance direction of the conveyance to be reversed. An image may be generated. When generating a transmission image only in the same direction as the conveyance direction of the conveyance performed in the foreign substance contamination inspection, the temporary stop of X-ray irradiation, which will be described in detail later, is performed after the inspection object 1 is detected. The conveyance may be reversed to return to the original stop position, and stopped until the conveyance is started again from the original stop position.

  The CPU 542 also controls the generation of X-rays based on the detection signal of one of the passage detection signal and the arrival detection unit 115 input from the passage detection unit 114 in the automatic setting of the inspection condition defining parameter. A source control signal to be transmitted is output to the X-ray generator 120, and a transport control signal for controlling transport is output to the transport unit 110.

  When the notification detection signal is input from the passage detection unit 114 and the passage detection unit 114 is provided in the relative positional relationship shown in FIG. 4 or 6 with respect to the X-ray line sensor 130, the CPU 542 After 1 passes through the monitoring position of the passage detecting means 114, the time required for completely passing through the X-ray line sensor 130 (the inspection object 1 moves to the position of the inspection object 1 ′ shown in FIG. 6) ( Hereinafter, after the passage time has passed, a conveyance control signal for decelerating the conveyance speed is output to the conveyance driving unit 113 of the conveyance unit 110.

  In the case where the passage detection means 114 is provided on the exit 221b side of the X-ray line sensor 130 and the inspection object 1 is transported from the stop position on the exit 221b side to the entrance 221a side, the CPU 542 Works as well. When the passage detection means 114 is provided on the outlet 221b side of the X-ray line sensor 130 and the inspection object 1 is transported from the stop position on the inlet 221a side to the outlet 221b side, the inspection object 1 The time required for the inspected object 1 to completely pass through the X-ray line sensor 130 after detecting that it has entered the monitoring position of the light projecting / receiving device as the passage detecting means 114 (hereinafter referred to as elapsed time after entering). ) Elapses, a conveyance control signal for decelerating the conveyance speed is output to the conveyance driving means 113.

  Even when the passage detection means 114 is provided on the outlet 221b side of the X-ray line sensor 130 and the inspection object 1 is transported from the stop position on the inlet 221a side to the outlet 221b side, the inspection object 1 After an elapse time after entering after detecting that the projector has entered the monitoring position of the light projecting / receiving device serving as the passage detecting means 114, a transport control signal for reducing the transport speed is output to the transport driving means 113. It is assumed that the information about the elapsed time after passage and the elapsed time after entry is written in the EEPROM 545 in advance. However, it may be read from the EEPROM 545 and stored in the RAM 544 in advance. The ROM 543 stores information on the distance necessary to calculate the elapsed time after passage and the elapsed time after entry, information on the conveyance speed, and the like, and the elapsed time after passage based on these information stored in the ROM 543. Alternatively, the elapsed time after entering may be calculated.

  The control processing unit 140 holds and operates the following information in order to perform control to reverse the transport direction of the transport unit 110. First, information on a position (hereinafter referred to as a target position) predetermined as a position desired to be stopped in each conveyance direction and information on a braking distance required to stop conveyance for each inspection object 1 are stored in advance in EEPROM 545. It is assumed that the information is stored in the memory. Note that time change data (hereinafter referred to as a conveyance speed profile) of the conveyance speed to be controlled may be further stored.

  Here, as a method of stopping the inspection object 1 after passing the X-ray line sensor 130, a position obtained by subtracting the braking distance with respect to the inspection object 1 from the target position determined according to the conveyance direction (hereinafter referred to as a braking restriction position). Or a method of stopping the inspection object 1 by stopping the driving of the conveyance driving means 113 at a position before the braking limit position (hereinafter referred to as inertia stop method), or a predetermined position before the braking limit position. For example, there is a method of decelerating the conveyance speed with the determined conveyance speed profile and stopping at the target position (hereinafter referred to as a deceleration control stop method). Making the target position farthest from the X-ray line sensor 130 (or the X-ray generator 120) in the detection space means that the conveyance speed is increased to the required conveyance speed. It is easy to secure a long distance, which is preferable.

  Hereinafter, the operation of each component in the automatic setting of the inspection condition defining parameter will be described with reference to FIG. Here, as the inspection condition defining parameters, for example, in order to mask the amount of X-ray transmission, the intensity of X-rays, the threshold for mixing determination, the type of transmission image creation processing, and what is intentionally added to the inspection object The mask area is increased. In setting the inspection condition defining parameters, the operator simply opens the transport unit front panel 22 and places the inspection object 1 in the detection space. After that, any of the panels 21, 22, 23 is also not open.

  In the following description, it is assumed that the control is performed from the state where the inspection object is stopped at the position of the inspection object 1 shown in FIG. First, in order to start the conveyance of the inspection object 1 from the stop position to the exit 221b side, a conveyance control signal for controlling the rotation of the conveyance driving unit 113 so that the conveyance belt 111 moves at a predetermined conveyance speed profile. The data is output from the CPU 542 of the control processing unit 140 to the transport driving unit 113 via the output interface 546.

  As the above-described conveyance speed profile, for example, as shown in FIG. 6B, the conveyance speed increases at a constant rate with respect to time, and before the inspection object 1 reaches the monitoring position of the passage detection unit 114. At a predetermined transport speed (hereinafter referred to as a steady transport speed), the steady transport speed is maintained until the inspection object 1 has passed the X-ray line sensor 130, and then transported at a constant rate with respect to time. Some decrease in speed. The conveyance speed profile shown in FIG. 6B is also an example when stopping by the deceleration control stop method.

  However, the above-described conveyance speed profile is not limited to the conveyance speed profile shown in FIG. 6B, and passes through the X-ray line sensor 130 after the inspection object 1 enters the monitoring position of the passage detection unit 114. Any other conveyance speed profile may be used as long as the steady conveyance speed can be maintained until the process is completed. FIG. 6A is a graph showing the relationship between the transport distance and the transport speed when transported with the transport speed profile shown in FIG. It is assumed that the conveyance speed control data for specifying the rotation speed of the conveyance driving unit 113 in order to realize the above-described conveyance speed profile is written in the EEPROM 545 in advance. However, it may be read from the EEPROM 545 and stored in the RAM 544 in advance.

  FIG. 6C is a diagram showing a change in X-ray intensity when an operation for automatically setting inspection condition defining parameters is started. FIG. 6D is applied to the X-ray generator 120. It is a figure which shows the change of a voltage. In a state before the inspection object 1 starts to be conveyed from the stop position on the inlet 221a side to the outlet 221b side and the inspection object 1 enters the monitoring position of the passage detection means 114, the light projecting / receiving device as the passage detection means 114 Generates a direct-current signal having a predetermined level that is equal to or higher than the noise level, and outputs it to the control processing unit 140 as a passage detection signal.

  Next, when the inspection object 1 enters the monitoring position of the passage detection means 114, the light emitted from the projector is blocked by the inspection object 1, and a DC signal having a level of zero, that is, a noise level, passes from the light receiver. The detection signal is output to the control processing unit 140. Hereinafter, the level of the DC signal output from the light receiver to the control processing unit 140 when the light emitted from the projector is blocked by the inspection object 1 is simply referred to as level zero.

  Further, when the inspection object 1 is conveyed in the direction toward the outlet 221b, the inspection object 1 passes through the monitoring position of the passage detection means 114, and the output from the light receiver becomes a predetermined value of level zero or more again. The CPU 542 of the control processing unit 140 detects that the level of the signal output from the passage detection unit 114 has risen from a level zero to a predetermined value, and the inspection object 1 has passed the monitoring position of the passage detection unit 114. Is detected.

  When the CPU 542 of the control processing unit 140 detects that the inspection object 1 has passed the monitoring position of the passage detection unit 114, either the inertia stop method or the deceleration control stop method is designated as a method for stopping the conveyance. The following processing is performed according to the specified stopping method.

  First, when the inertial stop method is designated, the CPU 542 of the control processing unit 140 reads the information on the braking distance and the target position from the EEPROM 545 (reads out and stores in the RAM 544 in advance, and reads out from the RAM 544). The braking limit position is calculated, and a conveyance control signal for stopping the conveyance driving unit 113 at a predetermined position before the braking limitation position is output to the conveyance driving unit 113. In addition, the CPU 542 outputs a drive control signal for stopping driving to the transport driving unit 113 and measures the elapsed time and waits until a predetermined time elapses. Here, the predetermined time is set to be equal to or longer than the time from when the conveyance control signal for stopping driving is output to the conveyance driving means 113 until the inspection object 1 is stopped.

  On the other hand, when the deceleration control stop method is designated as a method for stopping the conveyance, since the conveyance speed control data for realizing the designated conveyance speed profile has already been read from the EEPROM 545, the conveyance is continued. A transport control signal for controlling the transport speed according to the speed control data is output to the transport driving unit 113. The control processing unit 140 waits until the time when the conveyance speed profile becomes zero after the conveyance control signal for decelerating the conveyance speed is output, and waits for the inspection object 1 to stop. Here, when the conveyance is stopped because the conveyance direction is reversed by the conveyance control performed by the control processing unit 140, at least one of the shielding curtains positioned forward in the conveyance direction with respect to the X-ray line sensor is opened by the inspection object. It is not possible to.

  Next, the control processing unit 140 outputs a conveyance control signal to the conveyance driving unit 113, and reverses the conveyance direction of the conveyance belt 111 when determining that a predetermined time determined for each method for stopping conveyance has elapsed. To start conveyance. The operation for starting the conveyance after the reversal of the conveyance direction is the same as the operation before the reversal, and the description thereof is omitted. When the inspection object 1 is conveyed in the conveyance direction after reversal and the inspection object 1 passes over the X-ray line sensor 130 and enters the monitoring position of the passage detection means 114, the light emitted from the projector is inspected. 1 and is output from the light receiver to the control processing unit 140 as a passing detection signal.

  When detecting that the level of the signal output from the light receiver has changed to zero, the CPU 542 of the control processing unit 140 measures the elapsed time from when the signal level has changed to level zero, Information is read from the EEPROM 545 (may be read in advance and stored in the RAM 544 and read from the RAM 544).

  When the CPU 542 determines that the elapsed time during the measurement has reached the elapsed time after the entry, the CPU 542 performs the same control as that performed in the conveyance from the inlet 221a side to the outlet 221b side, and the inspection object 1 enters the inlet. Stop at the target position (stop position) on the 221a side. When the control processing unit 140 outputs the transport control signal to the transport driving unit 113 and determines that a predetermined time has elapsed, that is, when the control processing unit 140 determines that the inspection object 1 has stopped at the target position on the inlet 221a side, The operation with bidirectional conveyance is repeated as many times as input through an operation unit (not shown) to automatically set the inspection condition defining parameter.

  In addition, although it has been described that the inspection unit 1 is set in the detection space by opening the transport unit front panel 22, the inspection condition defining parameter is set. The inspection condition defining parameter may be set after the transport control means 144 moves the control position to the control start position.

  As described above, in the automatic setting of the parameters that define the inspection conditions, the conveyance control unit within the predetermined time from when the passage detection unit detects that the inspection object has passed over the X-ray line sensor. Transport control so that at least one of the shielding curtains located in front of the transport direction with respect to the X-ray line sensor is not opened by the inspection object when transport is stopped because the transport direction is reversed. Therefore, during the parameter setting operation, X-rays can be prevented from leaking outside from the X-ray foreign object detection device, and the safety of the operator can be ensured.

  In addition, the conveyance control means starts conveyance control to reduce the conveyance speed immediately after the passage detection means detects that the inspection object has passed on the X-ray line sensor in the automatic setting of the parameters that define the inspection conditions. Since the inspection object is stopped at the predetermined target position, the time required for the conveyance control for stopping the inspection object can be lengthened, and the inspection object can be easily stopped at the target position. .

  In addition, the conveyance control means stops the inspection object at a predetermined position in the vicinity of the nearest shielding curtain located forward in the conveyance direction with respect to the X-ray line sensor in the automatic setting of the parameters defining the inspection conditions. Since the conveyance control is performed as the target position, a long conveyance distance for increasing the conveyance speed to the required conveyance speed can be secured when the conveyance direction is switched and the conveyance is started.

  Further, in the automatic setting of parameters that define the inspection conditions, when the arrival detection means detects that the inspection object has reached the monitoring area, the conveyance control means performs the conveyance control so as to stop the conveyance. It is possible to prevent the inspection object from opening the external shielding curtain and leaking X-rays.

  The X-ray foreign object detection device according to the present invention is useful for an X-ray foreign object detection device and the like that have an effect of preventing leakage of X-rays from the X-ray foreign object detection device when performing parameter setting processing. It can also be applied to.

Explanatory drawing which shows notionally the block structure of the X-ray foreign material detection apparatus which concerns on embodiment of this invention The perspective view which shows an example of the X-ray foreign material detection apparatus which concerns on embodiment of this invention Sectional view in a plane parallel to the conveyor belt surface on the conveyor belt surface of the X-ray foreign matter detector Sectional drawing along the conveyance direction which illustrates notionally the structure of the space vicinity where the to-be-inspected object in a housing | casing is conveyed. The figure which shows the block configuration of the control processing part which comprises the X-ray foreign material detection apparatus which concerns on embodiment of this invention. Explanatory drawing for demonstrating operation | movement of the X-ray foreign material detection apparatus which concerns on embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inspection object 11, 12 Shielding curtain 20 Case 21 Radiation source front panel 22 Conveyance part front panel 23 Rear panel 24 Fixed part 100 X-ray foreign material detection apparatus 110 Conveyance part 111 Conveyance belt 112 Roller 113 Conveyance drive means 114 Passing detection means DESCRIPTION OF SYMBOLS 115 Arrival detection means 120 X-ray generator 121 X-ray tube 122 Irradiation slit 130 X-ray line sensor 140 Control processing part 141 Image processing means 142 Judgment means 143 X-ray control means 144 Conveyance control means 150 Display part 221, 221a, 221b Conveyance口 222 Hinge 541 Input interface 542 CPU
543 ROM
544 RAM
545 EEPROM
546 Output interface

Claims (4)

An X-ray foreign matter detection apparatus (100) for inspecting whether or not foreign matter is mixed in the inspection object by irradiating the inspection object (1) with X-rays,
A transport section (110) for transporting the inspection object;
An X-ray generator (120) for generating X-rays to be irradiated onto an object to be inspected conveyed by the conveying unit;
An X-ray line sensor (130) that senses the amount of X-rays transmitted through the inspection object among the X-rays irradiated to the inspection object;
The transport unit covers a space including at least a part of a transport path for transporting the inspection object, accommodates the X-ray generator and the X-ray line sensor therein, and transports the inspection object. A housing having an inlet and an outlet;
In the X-ray foreign object detection device comprising a plurality of shielding curtains provided above the conveyance path in the housing and preventing X-rays from leaking from the entrance and the exit,
Passage detecting means for detecting that the inspection object has passed over the X-ray line sensor;
When carrying out automatic setting of parameters for prescribing the inspection object in advance by the conveyance unit and prescribing the inspection conditions, predetermined conveyance control including control for reversing the conveyance direction conveyed by the conveyance unit is performed. Carrying control means (144) to perform ;
Stop conveyance of the inspection object in order to reverse the conveyance direction at a position where at least one of the shielding curtains located in front of the X-ray line sensor cannot be opened by the inspection object. Storage means for storing as a target position at the time ,
The transport control means stops the inspection object at the target position stored in the storage means after the passage detection means detects that the inspection object has passed over the X-ray line sensor. X-ray foreign material detecting apparatus characterized by performing the conveyance control to. The storage means further stores time change data of the conveyance speed,
The conveyance control means uses the time change data of the target position and the conveyance speed stored in the storage means after the passage detection means detects that the inspection object has passed over the X-ray line sensor. The X-ray foreign object detection device according to claim 1, wherein the conveyance control is performed to stop the inspection object based on the inspection object . The storage means further stores a braking distance necessary to stop the conveyance,
The conveyance control means detects the inspection object based on the target position and the braking distance stored in the storage means after the passage detection means detects that the inspection object has passed over the X-ray line sensor. X-ray foreign material detecting apparatus according to claim 1, characterized in that for conveying control to stop the test substance. With the arrival detection means for detecting the fact that the object to be inspected reaches the monitoring area in the vicinity of the shielding curtain nearest located in the conveying direction forward relative to the X-ray line sensor,
2. The conveyance control unit according to claim 1, wherein the conveyance control unit performs the conveyance control so as to stop conveyance when the arrival detection unit detects that the inspection object has reached the monitoring area. Item 4. The X-ray foreign object detection device according to any one of Items 3 to 3.

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