JP2009192267A - X-ray inspection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an X-ray inspection apparatus capable of avoiding the lowering of a detection capacity by eliminating the problem of polarization on the assumption of the use of a direct conversion type X-ray sensor. <P>SOLUTION: The X-ray inspection apparatus 1 includes an X-ray irradiator 7, the X-ray line sensor 8 having the direct conversion type X-ray sensor, a belt conveyor 6 for feeding an article 12, a control part 30 for controlling the bias voltage applied to the X-ray line sensor 8, a clocking means 35 for detecting a continuous applying time for continuously applying the bias voltage, and a stop control part 60 for stopping the supply of the article 12 to the belt conveyor 6 with respect to the processor 25 of the front stage of the X-ray inspection apparatus 1. When the clocking means 35 detects that the continuous applying time exceeds a predetermined time, the stop control part 60 temporarily stops the supply of the article 12 to the belt conveyor 6 with respect to the processor 25 of the front stage of the X-ray inspection apparatus 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  Conventionally, in the food industry, indirect conversion type X-ray sensors have been widely used as X-ray sensors used in X-ray inspection apparatuses for inspecting the presence or absence of foreign matters in food. In an indirect conversion type X-ray sensor, X-rays that have passed through an inspection object are converted into visible light by a scintillator, and visible light emitted from the scintillator is converted into an electrical signal by a photodiode.

  However, the indirect conversion type X-ray sensor has a drawback in that the foreign matter detection performance is low because the spatial resolution is reduced due to scattering of light inside the scintillator. On the other hand, due to consumer demands for food safety, high detection performance has been required even for food X-ray inspection apparatuses. Even in an indirect conversion type X-ray sensor, it is possible to increase detection performance by increasing the X-ray dose. However, when the irradiation X-ray dose is increased, the X-ray dose that passes through the scintillator and is applied to the photodiode also increases. As a result, the durability of the photodiode is lowered and the frequency of parts replacement is increased, which increases the user's economic burden.

  Under such circumstances, the food industry is expected to put the X-ray sensor of the direct conversion method into practical use instead of the indirect conversion method. The direct conversion type X-ray sensor is currently used mainly for CT apparatus in the medical field, and a semiconductor sensor (CdTe sensor) using cadmium telluride (CdTe) is known. For example, Patent Document 1 below discloses an example of a CT apparatus using a CdTe sensor. Further, for example, Patent Document 2 below discloses an example of a radiation detection method using a CdTe sensor. The direct conversion type X-ray sensor does not include a scintillator, and the X-ray transmitted through the inspection object is directly converted into an electric signal. The direct conversion type X-ray sensor has a high spatial resolution because it is not affected by light scattering by the scintillator, and also has a high X-ray conversion efficiency. Therefore, compared with the indirect conversion type X-ray sensor, the irradiation X-ray dose is small. High-definition images can be obtained. Therefore, since the irradiation X-ray dose can be suppressed, it is possible to suppress a decrease in durability of the semiconductor sensor due to the X-ray irradiation.

JP 2003-294844 A Japanese Patent No. 3151487

  As described above, the direct conversion type X-ray sensor is expected to be put into practical use also in the food industry, but there is a particular problem when the direct conversion type X-ray sensor is used in the food industry. In other words, in the food industry, unlike CT apparatuses in the medical field, there is a situation in which X-ray inspection apparatuses are used continuously for a long time. Some food factories have a production line that operates all day, and an X-ray inspection apparatus incorporated in such a production line inevitably operates all day.

  When the direct conversion type X-ray sensor is continuously used for a long time, the influence of polarization (polarization) becomes large. When polarization occurs, the sensitivity of the X-ray sensor decreases, and as a result, the detection performance of the X-ray inspection apparatus also decreases. Therefore, when a direct conversion type X-ray sensor is used in the food industry, it is necessary to solve the polarization problem and avoid a decrease in detection performance while assuming continuous operation for a long time.

  The present invention has been made in view of such circumstances, and on the premise of using a direct conversion type X-ray sensor, an X-ray inspection apparatus capable of solving the problem of polarization and avoiding deterioration in detection performance is obtained. For the purpose.

  An X-ray inspection apparatus according to a first aspect of the present invention is an X-ray inspection apparatus that inspects an article by irradiating the article to be inspected with X-rays and detecting the X-ray transmitted through the article. An X-ray irradiation unit, an X-ray detection unit having an X-ray sensor of a type that directly converts X-rays into an electrical signal, and the article between the X-ray irradiation unit and the X-ray detection unit A transfer unit that transfers the article, a first control unit that controls a bias voltage applied to the X-ray sensor, and the bias voltage are continuously applied so as to pass through the X-ray irradiation region. A time detection unit that detects a continuous application time; and a stop control unit that stops the supply of the article to the transport unit with respect to a processing device in the previous stage of the X-ray inspection apparatus, and the continuous application time is a predetermined value. When the time detection unit detects that the time has been exceeded, Serial stop control unit is characterized by temporarily stopping the supply of articles to the conveyor section to the preceding processing unit.

  The X-ray inspection apparatus according to the second invention is the X-ray inspection apparatus according to the first invention, particularly when the time detection unit detects that the continuous application time exceeds the predetermined time. The control unit 1 stops application of an effective bias voltage to the X-ray sensor.

  The X-ray inspection apparatus according to a third aspect of the invention further includes an article detection unit that detects whether or not the article is present on the transport unit, in the X-ray inspection apparatus according to the second aspect of the invention, Even if the continuous application time is equal to or shorter than the predetermined time, the first control unit, based on the detection signal from the article detection unit, within the period in which the article is not present on the transport unit, The application of an effective bias voltage to the X-ray sensor is stopped.

  The X-ray inspection apparatus according to a fourth aspect of the invention is the X-ray inspection apparatus according to the second aspect of the invention, particularly comprising a second control unit for controlling the X-ray irradiation from the X-ray irradiation unit, and the continuation. When the time detection unit detects that the application time exceeds the predetermined time, the second control unit stops the X-ray irradiation from the X-ray irradiation unit.

  An X-ray inspection apparatus according to a fifth aspect of the invention is the X-ray inspection apparatus according to the fourth aspect of the invention, particularly comprising an article detection unit for detecting whether or not the article is present on the transport unit, Even if the continuous application time is equal to or shorter than the predetermined time, the second control unit, based on the detection signal from the article detection unit, within the period in which the article does not exist on the transport unit, X-ray irradiation from the X-ray irradiation unit is stopped.

  The X-ray inspection apparatus according to the sixth invention is the X-ray inspection apparatus according to the first invention, particularly when the time detection unit detects that the continuous application time exceeds the predetermined time. The information processing device further includes notification means for notifying an operator that an operation for stopping application of an effective bias voltage to the X-ray sensor is to be performed.

  The X-ray inspection apparatus according to a seventh aspect of the invention is the X-ray inspection apparatus according to the sixth aspect of the invention, particularly comprising an article detection unit for detecting whether or not the article is present on the transport unit, Even if the continuous application time is equal to or shorter than the predetermined time, the notifying unit detects the X-ray sensor within a period in which the article is not present on the transport unit based on a detection signal from the article detection unit. The operator is notified that an operation for stopping the application of an effective bias voltage to the battery is to be performed.

  The X-ray inspection apparatus according to an eighth aspect of the invention is the X-ray inspection apparatus according to the sixth aspect of the invention, particularly when the time detection unit detects that the continuous application time has exceeded the predetermined time. The means further notifies the operator that an operation for stopping the X-ray irradiation from the X-ray irradiation unit should be performed.

  The X-ray inspection apparatus according to a ninth aspect of the invention is the X-ray inspection apparatus according to the eighth aspect of the invention, particularly comprising an article detection unit for detecting whether or not the article is present on the transport unit, Even if the continuous application time is equal to or shorter than the predetermined time, the notifying unit performs the X-ray irradiation within a period in which the article is not present on the transport unit based on a detection signal from the article detection unit. The operator is notified that an operation for stopping the irradiation of X-rays from the unit is to be performed.

  According to the X-ray inspection apparatus according to the first to ninth aspects, the time detection unit detects the continuous application time during which the bias voltage is continuously applied. When the time detection unit detects that the continuous application time exceeds the predetermined time, the stop control unit temporarily stops the supply of articles from the preceding processing apparatus to the transport unit. Therefore, even if polarization has occurred in the X-ray sensor due to continuous use up to that time, the characteristics of the X-ray sensor are restored to the initial characteristics by stopping the bias application within the period when the supply of the article is stopped. Therefore, it is possible to avoid a decrease in detection performance.

  In particular, according to the X-ray inspection apparatus according to the second aspect of the present invention, the bias application is automatically stopped by the first control unit, so that the recovery operation from the polarization state can be reliably performed.

  In particular, according to the X-ray inspection apparatus according to the third aspect of the present invention, the occurrence of uninspected articles can be avoided and stopped by executing a bias application stop operation within a period in which the articles are not present on the transport unit. It is possible to suppress the frequency of execution of the article supply stop operation by the control unit.

  In particular, according to the X-ray inspection apparatus according to the fourth invention, the X-ray source and the X-ray sensor deteriorate due to the X-ray irradiation by stopping the X-ray irradiation from the X-ray irradiation unit. It becomes possible to suppress.

  In particular, according to the X-ray inspection apparatus according to the fifth aspect of the present invention, the generation of uninspected articles can be avoided by executing the X-ray irradiation stop operation within a period in which the articles are not present on the transport unit.

  In particular, according to the X-ray inspection apparatus according to the sixth aspect of the invention, the X-ray sensor can be recovered from the polarization state by the operator performing a bias application stop operation.

  In particular, according to the X-ray inspection apparatus according to the seventh aspect of the invention, the operation of stopping the bias application is performed within a period in which the article is not present on the transport unit, thereby preventing the occurrence of an uninspected article and stopping it. It is possible to suppress the frequency of execution of the article supply stop operation by the control unit.

  In particular, according to the X-ray inspection apparatus according to the eighth aspect of the invention, the operator performs a stop operation of the X-ray irradiation, thereby suppressing the progress of deterioration of the X-ray source and the X-ray sensor due to the X-ray irradiation. It becomes possible.

  In particular, according to the X-ray inspection apparatus according to the ninth aspect of the present invention, the generation of uninspected articles can be avoided by performing the operation of stopping the X-ray irradiation within a period in which the articles are not present on the transport unit.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the element which attached | subjected the same code | symbol in different drawing shall show the same or corresponding element.

  FIG. 1 is a front view schematically showing an overall configuration of an X-ray inspection apparatus 1 according to an embodiment of the present invention. As shown in FIG. 1, the X-ray inspection apparatus 1 includes an upper housing 2, a shield box 3, and a lower housing 4. The upper housing 2 is provided with a monitor with a touch panel function (display / input unit 5), a reset switch 50, and a speaker 51.

  The shield box 3 has a function of preventing X-rays from leaking to the outside. An X-ray irradiation unit 7 and an X-ray detection unit 8 are disposed in the shield box 3. The X-ray irradiation unit 7 irradiates the article 12 such as food that is the inspection target with X-rays. The X-ray detection unit 8 detects X-rays that have been irradiated from the X-ray irradiation unit 7 and transmitted through the article 12. If foreign matter is mixed in the article 12, the intensity of X-rays detected by the X-ray detection unit 8 is extremely reduced at the portion where the foreign matter is mixed. Thereby, the magnitude | size and mixing location of a foreign material can be specified.

  A belt conveyor 6 is disposed in the shield box 3. The belt conveyor 6 conveys the article 12 so that the article 12 passes through the X-ray irradiation region 100 (see FIG. 2) between the X-ray irradiation unit 7 and the X-ray detection unit 8. That the article 12 has been supplied to the X-ray inspection apparatus 1 from the processing apparatus 25 upstream of the X-ray inspection apparatus 1 at the upstream end of the belt conveyor 6 (that is, outside the shield box 3 near the article carry-in entrance 17). A photosensor 15 for detection is provided. That is, the photo sensor 15 can detect that the article 12 has reached the upstream end of the belt conveyor 6. The shield box 3 is provided with an article carry-in port 17 near the upstream end of the belt conveyor 6 and an article carry-out port 18 near the downstream end.

  A computer 9 for performing operation control and data processing of the X-ray inspection apparatus 1 is disposed in the lower housing 4.

  On the upstream side of the belt conveyor 6, a belt conveyor 10 for carrying the article 12 from the upstream processing device 25 to the X-ray inspection apparatus 1 is provided. A belt conveyor 11 for carrying out the inspected article 12 from the X-ray inspection apparatus 1 is provided on the downstream side of the belt conveyor 6. The belt conveyor 11 is provided with an arbitrary sorting mechanism 20 for sorting non-defective products and defective products based on, for example, inspection results from the X-ray inspection apparatus 1.

  FIG. 2 is a perspective view showing an internal configuration of the shield box 3 shown in FIG. An X-ray irradiator (hereinafter also referred to as “X-ray irradiator 7”) as an X-ray irradiator 7 is disposed above the belt conveyor 6. Below the belt conveyor 6, an X-ray line sensor (hereinafter also referred to as “X-ray line sensor 8”) as the X-ray detection unit 8 is disposed. The X-ray line sensor 8 includes a plurality of X-ray detection elements 8a arranged in a straight line. The plurality of X-ray detection elements 8 a are arranged in parallel along the short side direction of the belt conveyor 6, that is, the direction orthogonal to the conveying direction of the article 12 by the belt conveyor 6. As shown as an X-ray irradiation region 100 in FIG. 2, the X-ray irradiator 7 irradiates the X-ray line sensor 8 with X-rays in a fan shape.

  The X-ray detection element 8a is a direct conversion type X-ray sensor, and converts the irradiated X-rays directly into an electric signal by an X-ray conversion film made of CdTe or the like. In a direct conversion type X-ray sensor, when an X-ray conversion film to which a bias voltage is applied is irradiated with X-rays, charges (electron-hole pairs) are generated in the X-ray conversion film according to the irradiated X-ray dose. Is excited and a current flows. The current value is converted into a voltage value by a current / voltage conversion circuit and output as data.

  FIG. 3 is a circuit diagram showing a bias application circuit to the X-ray line sensor 8. The power supply 40 supplies a bias voltage (hereinafter also referred to as “effective bias voltage”) that can operate the X-ray line sensor 8. A switch 31 made of a transistor or a semiconductor relay is connected between the power supply 40 and the X-ray line sensor 8. When the switch 31 is ON, a bias voltage is applied from the power supply 40 to the X-ray line sensor 8, while when the switch 31 is OFF, the bias voltage is applied from the power supply 40 to the X-ray line sensor 8. Is not applied. A current / voltage conversion circuit 8 </ b> A is connected to the X-ray line sensor 8. The current / voltage conversion circuit 8A changes the current value flowing through the X-ray line sensor 8 to a voltage value and outputs it as data (voltage signal). Data output from the current / voltage conversion circuit 8A is input to the computer 9, and an image of the article 12 is created by the computer 9.

  FIG. 4 is a block diagram showing a functional configuration of the X-ray inspection apparatus 1. The computer 9 includes a CPU 21 and a memory 22 such as a ROM or a RAM that can be referred to by the CPU 21. An X-ray irradiator 7, a current / voltage conversion circuit 8 </ b> A, a display / input unit 5, a photo sensor 15, a switch 31, a speaker 51, a reset switch 50, and a distribution mechanism 20 are connected to the computer 9.

  By the way, in the direct conversion type X-ray sensor, it is known that when a bias voltage is continuously applied, polarization occurs and the sensitivity of the X-ray sensor decreases. Hereinafter, a critical continuous application time in which the influence of polarization on sensitivity is significant is referred to as a limit time Tmax. That is, by continuously applying the bias voltage to the X-ray line sensor 8 for a time equal to or longer than the limit time Tmax, the influence of polarization becomes large and the sensitivity of the X-ray sensor is lowered. However, in reality, there is no clear critical value as the limit time Tmax, and the sensitivity of the X-ray sensor has started to decrease due to experiments or simulations at the development stage of the X-ray inspection apparatus or X-ray sensor. The value of the continuous application time at the time point (or the time point immediately before starting to decrease) is set as the limit time Tmax.

  In operation of the production line, if there are frequent rest periods in which the article 12 is not supplied to the X-ray inspection apparatus 1, the application of the bias voltage to the X-ray line sensor 8 is stopped within each rest period, so that the X-ray The line sensor 8 can be recovered from the polarization state. However, some food factories have production lines that are continuously operated throughout the day, and the X-ray inspection apparatus 1 incorporated in such a production line does not have a rest period and therefore cannot perform a recovery operation from the polarization state. . Therefore, the X-ray inspection apparatus 1 according to the present embodiment automatically detects that the time during which the bias voltage is continuously applied to the X-ray line sensor 8 exceeds a predetermined time, and in that case The supply of the article 12 to the belt conveyor 6 is temporarily stopped with respect to the preceding processing device 25. Then, during the stop period, the recovery operation from the polarization state of the X-ray line sensor 8 is executed automatically or manually. This will be specifically described below.

<When automatically recovering from the polarization state>
FIG. 5 is a block diagram showing a configuration related to the recovery operation from the polarization state. FIG. 6 is a timing chart for explaining the recovery operation from the polarization state.

  Referring to FIG. 5, control unit 30 and stop control unit 60 are realized as functions of computer 9 shown in FIG. 1. The detection signal S <b> 1 is input from the photosensor 15 to the control unit 30. In addition, information regarding the set driving speed of the belt conveyor 6 is input to the control unit 30 as a signal S2. The control unit 30 determines whether the article 12 exists on the belt conveyor 6 based on the detection signal S1 and the signal S2.

  After the article 12 is supplied from the belt conveyor 10 of the upstream processing apparatus 25 to the belt conveyor 6 of the X-ray inspection apparatus 1, the article 12 is discharged from the belt conveyor 6 to the belt conveyor 11 of the subsequent sorting mechanism 20. Before the next article 12 is supplied to the belt conveyor 6, the articles 12 are continuously present on the belt conveyor 6. In this case, the control unit 30 detects that the article 12 is continuously present on the belt conveyor 6. Note that the control unit 30 also allows the article 12 to be placed on the belt conveyor 6 even when the time interval from when the article 12 is discharged until the next article is supplied is less than a predetermined threshold (for example, about several seconds). It may be determined that they exist continuously.

  Further, information related to the limit time Tmax is registered in advance in the memory 22 illustrated in FIG. 4, and the control unit 30 can refer to the limit time Tmax by accessing the memory 22.

  The control unit 30 is connected to a time measuring means 35 such as a time counter. A time count value is input from the time measuring means 35 to the control unit 30 as a signal S3.

  Based on the signal S3, the control unit 30 counts the time during which the bias voltage is continuously applied to the X-ray line sensor 8 (hereinafter also referred to as “continuous application time”). When the continuous application time exceeds the limit time Tmax (or a time that Tmax is also slightly short), a stop command signal S4 of a high level (hereinafter referred to as “H level”) is sent to the stop control unit 60 (FIG. 6). Accordingly, the stop control unit 60 stops the supply of the article 12 to the X-ray inspection apparatus 1 with respect to the processing apparatus 25 at the previous stage.

  Further, after the time W has elapsed from time T1, the control unit 30 inputs a low level (hereinafter referred to as “L level”) signal S5 to the switch 31, thereby turning off the switch 31. Thereby, application of the bias voltage to the X-ray line sensor 8 is stopped. Here, the time W is a time required for discharging all articles 12 on the belt conveyor 6 to the belt conveyor 11 in the subsequent stage, and changes according to the driving speed of the belt conveyor 6.

  At the same time, the control unit 30 inputs an L level signal S6 to the X-ray irradiator 7. Thereby, X-ray irradiation from the X-ray irradiator 7 is stopped.

  When the bias application is stopped, the recovery operation from the polarization state of the X-ray line sensor 8 is performed. When the recovery operation from the polarization state is completed, the control unit 30 sends an L-level stop command signal S4 to the stop control unit 60 (see time T2 in FIG. 6). As a result, the stop control unit 60 releases the supply stop to the upstream processing apparatus 25, and as a result, the supply of the article 12 from the upstream processing apparatus 25 to the X-ray inspection apparatus 1 is resumed. At the same time, the control unit 30 resets the count value of the time measuring means 35 and starts counting the continuous application time again.

  Further, when the signal S4 changes from the H level to the L level at time T2, the control unit 30 immediately changes the signals S5 and S6 from the L level to the H level. Thereby, the application of the bias voltage to the X-ray line sensor 8 is restarted, and the X-ray irradiation from the X-ray irradiator 7 is also restarted.

  As described above, according to the X-ray inspection apparatus 1 according to the present embodiment, the time application means detects the continuous application time during which the bias voltage is continuously applied to the X-ray line sensor 8. When the continuous application time exceeds the limit time Tmax, the stop control unit 60 temporarily stops the supply of the article 12 from the preceding processing device 25 to the belt conveyor 6. Therefore, even if polarization has occurred in the X-ray line sensor 8 due to continuous use up to that time, by stopping the bias application within the period in which the supply of the article 12 is stopped, the characteristics of the X-ray line sensor 8 can be improved. Since the initial characteristics can be restored, it is possible to avoid a decrease in detection performance.

  Further, since the bias application is automatically stopped, the recovery operation from the polarization state can be surely executed.

  Further, by stopping the X-ray irradiation from the X-ray irradiator 7, it is possible to suppress the progress of deterioration of the X-ray source and the X-ray sensor due to the X-ray irradiation.

  As a modified example, if the control unit 30 detects a rest period in which the article 12 does not exist on the belt conveyor 6 based on the detection signal S1 and the signal S2 even if the continuous application time is equal to or less than the limit time Tmax, A stop operation of bias application and a stop operation of X-ray irradiation may be executed within the pause period. By executing the bias application stop operation during the suspension period, it is possible to avoid the occurrence of uninspected articles and to suppress the frequency of execution of the article supply stop operation by the stop control unit 60. Moreover, generation | occurrence | production of an uninspected article | item can be avoided by performing the stop operation | movement of X-ray irradiation within a rest period.

<When manually recovering from the polarization state>
FIG. 7 is a block diagram showing a configuration related to the recovery operation from the polarization state. Hereinafter, the difference from FIG. 5 will be mainly described.

  The control unit 30 counts the continuous application time based on the signal S3. When the continuous application time exceeds the limit time Tmax (or a time that Tmax is slightly shorter), an H level stop command signal S4 is sent to the stop control unit 60. Accordingly, the stop control unit 60 stops the supply of the article 12 to the X-ray inspection apparatus 1 with respect to the processing apparatus 25 at the previous stage.

  Further, the control unit 30 outputs a signal S9 toward the notification unit 70 along with the transmission of the stop command signal S4. The notification unit 70 corresponds to the display / input unit 5 and the speaker 51 shown in FIGS. Upon receiving the signal S9, the display / input unit 5 displays a text message prompting the operator to press the reset switch 50 on the display screen. At the same time, a voice message that prompts the operator to press the reset switch 50 is output from the speaker 51.

  When the operator presses the reset switch 50, a signal S8 is input to the control unit 30. Upon receiving the signal S8, the control unit 30 inputs the L level signal S5 to the switch 31, thereby turning off the switch 31. Thereby, application of the bias voltage to the X-ray line sensor 8 is stopped. At the same time, the control unit 30 inputs an L level signal S6 to the X-ray irradiator 7. Thereby, X-ray irradiation from the X-ray irradiator 7 is stopped.

  When the bias application is stopped, the recovery operation from the polarization state of the X-ray line sensor 8 is performed. When the recovery operation from the polarization state is completed, the supply of the article 12 from the processing apparatus 25 in the previous stage to the X-ray inspection apparatus 1 is resumed and the application of the bias voltage to the X-ray line sensor 8 is resumed. X-ray irradiation from the X-ray irradiator 7 is resumed.

  Even when the recovery operation from the polarization state is executed manually, it is possible to avoid a decrease in the detection performance of the X-ray line sensor 8 as in the case of executing it automatically.

  As a modified example, if the control unit 30 detects a rest period in which the article 12 does not exist on the belt conveyor 6 based on the detection signal S1 and the signal S2 even if the continuous application time is equal to or less than the limit time Tmax, By notifying the notification means 70 during the suspension period, the operator may be caused to perform a pressing operation of the reset switch 50 (that is, a bias application stop operation and an X-ray irradiation stop operation). By causing the bias application stop operation to be executed during the suspension period, it is possible to avoid the occurrence of uninspected articles and to suppress the frequency of execution of the article supply stop operation by the stop control unit 60. Moreover, generation | occurrence | production of an uninspected article | item can be avoided by performing stop operation | movement of X-ray irradiation within a rest period.

<Modification>
FIG. 8 is a diagram for specifically explaining the operation of stopping the application of bias to the X-ray line sensor 8. The switch 31 has terminals 71A to 71C. When the switch 31 is turned on, the terminals 71A and 71B are connected, and when the switch 31 is turned off, the terminals 71A and 71C are connected. Stopping the application of an effective bias voltage to the X-ray line sensor 8 means that the switch 31 is switched to the OFF state in FIGS.

  In FIG. 8A, the power source 70A supplies a minute voltage (for example, 0.1 V) having the same polarity as the power source 30, and even if the terminal 71A and the terminal 71C are connected to the X-ray line sensor 8. Since a sufficient bias voltage is not supplied, the X-ray line sensor 8 does not operate. In FIG. 8B, the terminal 71C is in an electrically floating state, and even if the terminal 71A and the terminal 71C are connected, a sufficient bias voltage is not supplied to the X-ray line sensor 8. The line sensor 8 does not operate. In FIG. 8C, the GND potential is supplied to the terminal 71C, and even if the terminal 71A and the terminal 71C are connected, a sufficient bias voltage is not supplied to the X-ray line sensor 8. The line sensor 8 does not operate. In FIG. 8D, the power source 70C supplies a minute voltage (for example, −0.1 V) having a polarity opposite to that of the power source 30, and even if the terminal 71A and the terminal 71C are connected, the X-ray line sensor. Since a sufficient bias voltage is not supplied to 8, the X-ray line sensor 8 does not operate.

It is a front view which shows typically the whole structure of the X-ray inspection apparatus which concerns on embodiment of this invention. It is a perspective view which shows the internal structure of the shield box shown in FIG. It is a circuit diagram which shows the bias application circuit to an X-ray line sensor. It is a block diagram which shows the function structure of a X-ray inspection apparatus. It is a block diagram which shows the structure relevant to the recovery operation from a polarization state. It is a timing chart for explaining recovery operation from a polarization state. It is a block diagram which shows the structure relevant to the recovery operation from a polarization state. It is a figure for demonstrating concretely the stop operation | movement of the bias application to a X-ray line sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 X-ray inspection apparatus 5 Display / input part 6 Belt conveyor 7 X-ray irradiator 8 X-ray line sensor 12 Article 15 Photo sensor 25 Previous stage processing apparatus 30 Control part 31 Switch 50 Reset switch 51 Speaker 60 Stop control part 100 X-ray Irradiation area

Claims (9)

An X-ray inspection apparatus that performs an inspection on the article by irradiating the article to be inspected with X-rays and detecting the X-ray transmitted through the article,
An X-ray irradiation unit;
An X-ray detector having an X-ray sensor of a type that directly converts X-rays into an electrical signal;
A transport unit that transports the product such that the product passes through an X-ray irradiation region between the X-ray irradiation unit and the X-ray detection unit;
A first controller for controlling a bias voltage applied to the X-ray sensor;
A time detection unit for detecting a continuous application time in which the bias voltage is continuously applied;
A stop control unit for stopping the supply of the article to the transport unit with respect to the processing apparatus in the previous stage of the X-ray inspection apparatus,
When the time detection unit detects that the continuous application time has exceeded a predetermined time, the stop control unit temporarily stops the supply of articles to the transport unit with respect to the processing apparatus at the previous stage. X-ray inspection equipment.   The said 1st control part stops the application of the effective bias voltage to the said X-ray sensor, when the said time detection part detects that the said continuous application time exceeded the said predetermined time. The X-ray inspection apparatus according to 1. An article detection unit for detecting whether the article is present on the transport unit;
Even if the continuous application time is equal to or shorter than the predetermined time, the first control unit, based on a detection signal from the article detection unit, within a period in which the article is not present on the transport unit, The X-ray inspection apparatus according to claim 2, wherein application of an effective bias voltage to the X-ray sensor is stopped. A second control unit for controlling the X-ray irradiation from the X-ray irradiation unit;
The said 2nd control part stops the irradiation of the X-ray from the said X-ray irradiation part, when the said time detection part detects that the said continuous application time exceeded the said predetermined time. The X-ray inspection apparatus described. An article detection unit for detecting whether the article is present on the transport unit;
Even if the continuous application time is equal to or shorter than the predetermined time, the second control unit, based on a detection signal from the article detection unit, within a period in which the article is not present on the transport unit, The X-ray inspection apparatus according to claim 4, wherein X-ray irradiation from the X-ray irradiation unit is stopped.   When the time detection unit detects that the continuous application time exceeds the predetermined time, the operator is notified that an operation for stopping the application of an effective bias voltage to the X-ray sensor should be performed. The X-ray inspection apparatus according to claim 1, further comprising notification means. An article detection unit for detecting whether the article is present on the transport unit;
Even if the continuous application time is equal to or shorter than the predetermined time, the notifying unit determines the X-ray within a period in which the article is not present on the transport unit based on a detection signal from the article detection unit. The X-ray inspection apparatus according to claim 6, wherein an operator is notified that an operation for stopping the application of an effective bias voltage to the sensor is to be performed.   When the time detection unit detects that the continuous application time exceeds the predetermined time, the notification means further performs an operation to stop the X-ray irradiation from the X-ray irradiation unit The X-ray inspection apparatus according to claim 6, which notifies a person. An article detection unit for detecting whether the article is present on the transport unit;
Even if the continuous application time is equal to or shorter than the predetermined time, the notifying unit determines the X-ray within a period in which the article is not present on the transport unit based on a detection signal from the article detection unit. The X-ray inspection apparatus according to claim 8, wherein the operator is notified that an operation for stopping irradiation of X-rays from the irradiation unit is to be performed.

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