JP2004069507A - Nondestructive inspection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact nondestructive inspection method which is superior in safety and is capable of being manufactured at low costs. <P>SOLUTION: While scanning an object (2) to be inspected with microwaves, reflected waves of the microwaves or transmitted waves are received. By comparing the output of the received waves with a reference value, the presence or the absence of planned contents (12) in the object is determined. When the contents are contents (such as CD-ROM) made of metals, the output (P1 and P4) of the received waves, when a scanning point (L) intersects edge parts of the object (2), is removed from the object of determination. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nondestructive inspection method suitable for inspecting the presence or absence of the contents of a product, and more particularly to a nondestructive inspection method using a microwave sensor.
[0002]
[Prior art]
As a nondestructive inspection method applied when inspecting the presence or absence of the contents of a product, a method using X-rays, a method using a proximity sensor, and the like are conventionally known. In the non-destructive inspection method using X-rays, an X-ray generator and an X-ray camera are arranged on both sides of an inspection target article in opposition, and the contents are determined based on an X-ray image transmitted through the inspection target article. Inspect for objects. In the non-destructive inspection method using the proximity sensor, a high-frequency flowing coil is brought close to the inspection target article, and the inductance of the detection coil changes through a mutual induction action. It detects metal objects.
[0003]
[Problems to be solved by the invention]
However, various problems have been pointed out in the nondestructive inspection method described above. That is, in the non-destructive inspection method using X-rays, since a X-ray harmful to the human body is handled, a sufficient shielding structure is required, which leads to an increase in size of the apparatus and an increase in cost. On the other hand, the nondestructive inspection method using the proximity sensor has the advantage of high safety and the ability to configure the device in a small size, but the detection distance is short due to its detection principle, and therefore the type of the inspection object is limited. The problem of being restricted has been pointed out.
[0004]
The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a nondestructive inspection method which can be manufactured at a small size and at low cost and is excellent in safety. It is in.
[0005]
Another object of the present invention is to provide a nondestructive inspection method capable of accurately detecting not only a metal body but also contents of various materials included in an inspection target article.
[0006]
Still other objects and operational effects of the present invention will be easily understood by those skilled in the art by referring to the description in the following specification.
[0007]
[Means for Solving the Problems]
The nondestructive inspection method of the present invention is to scan an article to be inspected with a microwave, receive a reflected wave or a transmitted wave thereof, and compare the received wave output with a reference value, whereby the article to be inspected is scheduled to be inspected. It is determined whether or not the contents exist.
[0008]
According to such a configuration, since microwaves are used as a detection medium, a higher level of safety can be realized as compared with those using X-rays, and the size of sensor devices used for inspection can be reduced. You can also. In addition, since the contents of an extremely wide range of materials can be inspected, for example, the presence or absence of metal parts in plastic parts, the presence or absence of an anti-theft aluminum tag, the presence or absence of cream in puff pastry, etc. It is expected to be applied to various inspections. In particular, when using a reflection type microwave sensor, it is effective for inspection objects that cannot be realized by the conventional inspection method, such as detection of liquid level in bottles and pottery that is not affected by bubbles. In addition to functioning, when a transmission type microwave sensor is used, detection and positioning of an appendix having a metal part in a magazine (such as a CD-ROM), detection of presence / absence or position over a conveyor, detection of wood gap position In addition, there is an advantage that it can be widely applied to objects which cannot be detected by the conventional method, such as detection of dryness of paper, tobacco, tea, and fiber.
[0009]
However, since a microwave is used as a detection medium, a case where a special device is required is also assumed. That is, when scanning the article to be detected with the microwave, the received wave output when the scanning point crosses the edge of the article may be significantly reduced regardless of the presence or absence of the metal content. Were found through intensive studies by the people. That is, for example, in the case of detecting an optical recording medium such as a CD or DVD included as an appendix in a book, if the edge of the book is scanned with a microwave, the edge of the book may be correlated with the wavelength of the microwave. Since the received wave output locally decreases, if the presence or absence of the content is simply determined based on the level of the received wave output, there is a risk that an erroneous determination may be made as it is. Therefore, in such a case, it is preferable to exclude the reception output when the scanning point crosses the edge of the article from the determination target. Here, in order to realize "removal from the determination target", it is possible to adopt a so-called time gate method or a synchronization detection method.
[0010]
A preferred non-destructive inspection method according to the present invention employing the "synchronous detection method" is to scan a book with a microwave using a microwave sensor, receive a reflected wave or a transmitted wave, and set the received output to a reference value. By comparing with the book, a non-destructive inspection method for determining whether or not the intended metal content exists in the book.
[0011]
This non-destructive inspection method includes a method in which, when a place where the metal content should exist in a book coincides with a scanning point of the microwave sensor, the microwave is moved so that the scanning point coincides with an edge of the book. A synchronization sensor is provided at a predetermined distance from the sensor, and the microwave sensor compares the reception output obtained in synchronization with the edge detection timing of the synchronization sensor with a reference value, thereby obtaining the metal content. A determination is made as to whether an object is present.
[0012]
Note that the “synchronous sensor” here may be any sensor that can detect the edge of a book, and examples thereof include a contact switch and a photoelectric sensor.
[0013]
As described above, according to the non-destructive inspection method of the present invention employing the “synchronization detection method”, by appropriately setting the distance between the microwave sensor and the synchronization sensor (the distance between the scanning points of both sensors), Can be matched with the timing at which the edge of the crosses the scanning point of the synchronous sensor and the timing at which the place where metal content should originally exist in the book crosses the scanning point of the microwave sensor. For this reason, it is possible to perform the accurate presence / absence determination of the content without erroneous determination without being affected by the received wave output when the scanning point of the microwave sensor crosses the edge of the book.
[0014]
In addition, the preferred non-destructive inspection method of the present invention employing the above-described “time gate method” is to scan a book with a microwave using a microwave sensor, receive a reflected wave or a transmitted wave, and output a received wave. Is compared with a reference value to determine whether or not a predetermined number of predetermined metal contents exist in the book.
[0015]
The non-destructive inspection method includes a method in which a microwave is scanned such that a scanning point of the microwave sensor continuously scans a place in the book where the metal content is to be present, so that the scanning point remains on the book. A gate sensor disposed at a predetermined distance from the sensor is provided, and the microwave sensor detects whether the reception output obtained during the generation of the detection output of the gate sensor exceeds or falls below a reference value. Then, it is determined whether or not the predetermined number of metal contents is present.
[0016]
According to such an inspection method, the number of times (1 or 2) the book edge crosses the scanning point of the microwave sensor during generation of the detection output of the gate sensor is specified in advance. By subtracting from the number of times the output exceeds or falls below the reference value), the metal contained in the book is not affected by the reception output when the edge of the book crosses the scanning point of the microwave sensor. It is possible to accurately determine whether or not there is a predetermined number of contents.
[0017]
As described above, according to the nondestructive inspection method of the present invention, various effects such as downsizing of the inspection apparatus, improvement of safety, and expansion of the applicable object can be achieved.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, some embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a configuration diagram of a bookbinding line to which the present invention is applied. In this application example, in a bookbinding line of a printing company or the like, a CD-ROM included in a book as an appendix is automatically detected by transmitting microwaves to the book.
[0019]
The bookbinding line is provided with a linear conveyor 1 for transporting a bundle of paper sheets 2 constituting a book, and the conveyor 1 sequentially transfers the bundle of paper sheets 2 placed at appropriate intervals. Conveyed. An endless conveyor 7 having an oval track is connected to the end of the conveyor 1, and a binder 7 a is attached at an appropriate interval on the endless conveyor 7, and has flowed on the conveyor 1. The sheet bundle 2 is sandwiched by the binder 7a, and then sent to a portion A surrounded by a dotted line in the figure to be subjected to a cutting process.
[0020]
An enlarged view of the part A is shown in FIG. As shown in the figure, a rotary cutter 3 and a dust suction pipe 4 for perfect binding are arranged in the section A. In this cutting step, the spine to which the sheet bundle 2 is glued is set. The cutting process is performed on the cover by the rotary cutter 3. This cutting treatment is for facilitating the impregnation of the adhesive.
[0021]
Returning to FIG. 1, the sheet bundle 2 having passed through the cutting process further advances forward while being sandwiched by the binder 7a, and is subsequently carried to the adhesive tank 5, where the spine cover is impregnated with the adhesive. Thereafter, the booklet is further transported forward by the endless conveyor 7 and the cover 9 supplied from the cover bundle 8 is glued to the spine. The sheet bundle 2 covered with the spine 9 in this way proceeds further forward and is discharged onto the table 11. Here, usually, the sheet bundle 2 is bundled into, for example, five books to form a book bundle 10, and further proceeds forward via the conveyor 17, and in the final step, the five sheets are stacked in a three-way manner. Is cut by the cutter blades 11a, 11b, 11c, whereby the three-sided edge is shaped, and the book is completed.
[0022]
By the way, in the above configuration, in the portion A in the figure, the cutting process is performed on the spine portion of the sheet bundle 2 by the rotary cutter 3, and at that time, as shown in FIG. As described above, if the CD-ROM 12 is accommodated in the book bundle 2 as an appendix, if the CD-ROM 12 is displaced and largely moves to the lower part of the sheet bundle 2, this is There is a problem that the rotary cutter 3 is damaged by being scraped.
[0023]
Therefore, in this embodiment, the sensor head for transmitting microwaves and the sensor head for receiving microwaves are disposed opposite to each other across a transport line on which the sheet bundle 2 is conveyed. It is checked whether the CD-ROM 12 is normally placed in the storage device.
[0024]
By the way, according to the earnest study of the present inventors, while scanning the article to be inspected with a microwave, the transmitted wave is received, and the received wave output is compared with a reference value, so that the contents of the article to be inspected are determined. In the inspection method for determining whether or not an object is present, it has been found that, depending on the article, it is necessary to exclude the reception output when the scanning point crosses the edge of the article from the determination target. FIG. 3 shows the contents of the test results supporting this finding.
[0025]
As shown in the drawing, in a state where the sensor head 13 for microwave transmission and the sensor head 14 for microwave reception are arranged to face each other, inspection is performed from the X direction orthogonal to the axis connecting them to the microwave existence region. It is assumed that the target article M enters. Here, the state where the tip end of the inspection target article M is approaching the microwave existence area (the amount of penetration of 0 mm) is “0 mm position”, and the state where it has reached almost the middle of the microwave existence area (the amount of penetration of 12.5 mm) is the same. The “central detection position” and the state immediately before exiting from the microwave existence region (entering amount 25 mm) are defined as “25 mm position”.
[0026]
A graph showing the relationship between the amount of entry of the inspection object M in this state and the reception level of the microwave is shown in FIG. As shown at point b in the graph, as a matter of course, at the “25 mm position”, the reception level when the article M to be detected is a magazine shows a sufficiently high value of about 500 mV, whereas the reception level is about 500 mV. The reception level when the article M is a metal plate is almost zero. Therefore, if the output level of the receiving sensor head 14 at the “25 mm position” is compared with an appropriate threshold level, it can be easily determined whether the inspection target article M is a magazine or a metal plate. However, attention must be paid to the "center detection position" shown at point a in the graph. That is, at this “center detection position”, the reception level is reduced to approximately 100 mV regardless of whether it is a magazine or a metal plate. Therefore, even if the above-described threshold value for determination is set to a considerably low value of, for example, about 100 mV, if the edge of the detection target article M is at point a in FIG. It is difficult to judge whether it is, and erroneous judgment cannot be avoided.
[0027]
Therefore, in the present invention, the reception output when the scanning point crosses the edge of the article, as represented by the point a, is excluded from the determination target, thereby eliminating the possibility of erroneous determination. I have. The contents of the inspection using such a microwave sensor will be described with reference to FIG.
[0028]
As shown in FIG. 1A, in the configuration of the transmission type sensor in which the transmission sensor head 13 and the reception sensor head 14 are arranged to face each other, the paper sheet is moved in the X direction orthogonal to the axis connecting the sensors. The bundle 2 is transported. At this time, it is assumed that the sheet bundle 2 includes a CD-ROM 12 as an appendix.
[0029]
FIG. 6B shows a change in the reception level accompanying the passage of the sheet bundle 2 at this time. As is apparent from FIG. At the points P1 and P4 passing through the edge of. Naturally, even in a region where the scanning line L crosses the CD-ROM 12, a large decrease in the reception level is seen from the point P2 to the point P3 in the figure.
[0030]
Therefore, in order to confirm that the CD-ROM 12 is located at the normal position in the sheet bundle 2, avoid the points P1 and P4 in the figure and adjust the reception level in the period between the points P2 and P3. It can be seen that comparison with a predetermined reference value is sufficient. Specifically, for example, as shown in FIG. 5, the trigger sensor 16 is provided so that the detection operation is performed in a state where the scanning line L is at the normal position of the CD-ROM 12 in the sheet bundle 2. That is, when the sheet bundle 2 enters the microwave existing area and its leading end reaches the trigger sensor 16, the trigger sensor 16 is activated and a predetermined pulse signal is obtained. If the reception output of the reception sensor head 14 is determined, the reception sensor head 14 is substantially at the center of the period between the points P2 and P3 without being affected by the points P1 and P4 in FIG. Of the CD-ROM 12 can be determined without erroneous determination.
[0031]
It should be noted that among various books, there is a case where two CD-ROMs 12a and 12b are included in one book in a shifted position. In such a case, it is possible to determine whether the CD-ROM is properly included in any number of two or more by counting the output of the sensor head 14 for reception. Also in this case, the influence of both edges of the sheet bundle 2 constituting the book appears, so that the same mask processing as in the case of the preceding one sheet is required. The contents of the countermeasure against erroneous detection using the time gate in such a case will be described with reference to FIG.
[0032]
As shown in FIG. 2A, in the case of a sheet bundle 2 including two CD-ROMs 12a and 12b, in this example, in the transport direction of the sheet bundle 2 (X direction in FIG. A trigger detection position TP and a microwave sensor detection position MP are provided. Here, the trigger detection position TP indicates the axis position of the trigger sensor, and the microwave sensor detection position MP indicates the axis position of the microwave sensor.
[0033]
In such a configuration, when a book (sheet bundle 2) including the two CD-ROMs 12a and 12b advances in the X direction in the drawing and the edge E1, which is the leading end, reaches the trigger sensor detection position TP, the same operation is performed. As shown in FIG. 2B, the reception level is greatly reduced as indicated by reference numeral P11. Thereafter, when the sheet bundle 2 further moves forward, the edge E1, which is the front end of the sheet bundle 2, reaches the microwave sensor detection position MP. Thereafter, the reception level fluctuates up and down as shown in FIG. 2B until the sheet bundle 2 has passed the microwave sensor detection position MP.
[0034]
At this time, as shown in FIG. 3B, before and after the normal detection output shown by reference numerals P12 and P13, the value of the reception level is changed to the edges E1 and E2 as shown by reference numerals P11 and P14. Greatly reduced in response to These reception levels are compared with an appropriate threshold value TH and binarized, and as shown in FIG. 3C, pulse signals S1 to S4 are obtained as outputs of the microwave sensor.
[0035]
On the other hand, as shown in FIG. 3D, on the output side of the trigger sensor, the trigger sensor detection position TP is set to “output ON” during a period T in which the width of the sheet bundle 2 in the front-rear direction is blocked. A wider pulse is obtained. Therefore, by opening the time gate only during the wide pulse having the period T and passing the output S1, S2, S3 of the microwave sensor, at least the influence of the edge E1 is avoided, and the CD-ROM 12a, Since the presence of 12b can be confirmed, the pulses S1, S2, and S3 that have passed through the time gate are counted each time. If the count result is "3", the CD-ROMs 12a and 12b are brought to the normal positions. The arrangement can be determined.
[0036]
However, since there is a slight error at the end of the output ON period T of the trigger sensor, there is a possibility that the microwave sensor output S4 may erroneously pass through the time gate. Thus, in this case, if the count output is "3" or "4", it is determined that the count is "normal", so that the two CD-ROMs 12a and 12b can be reliably determined. On the other hand, if the count result is "1" or "2", it is possible to determine "abnormal" such that one of the two CD-ROMs 12a and 12b does not exist at the normal position or has been forgotten.
[0037]
Next, the contents of the countermeasure against erroneous detection using the timing gate will be described with reference to FIG. In this example, as shown in FIG. 2A, two triggers are provided in front of the transport path where the sheet bundle 2 is transported, corresponding to the interval between just two CD-ROMs 12a and 12b. Sensor detection positions TP1 and TP2 are provided. In such a state, when the sheet bundle 2 moves forward on the conveyance path, when the optical axis of the microwave sensor reaches the center of the two CD-ROMs 12a and 12b, the same as FIG. As shown in FIG. 7E, trigger pulses S5 and S6 are obtained. Therefore, in synchronism with the time when these trigger pulses S5 and S6 are obtained, if the existence of the microwave sensor outputs S2 and S3 shown in FIG. , S4, the presence of the two CD-ROMs 12a, 12b at the appropriate positions can be reliably determined.
[0038]
Next, the content of the countermeasure against erroneous detection using two receiving heads will be described with reference to FIG. In this example, two reception sensor heads 14a and 14b are provided for one transmission sensor head 13 as shown in FIG. When such a configuration is adopted, as shown in FIG. 3B, “Reception A” which is the output of the first reception sensor head 14a and “Reception B” which is the output of the second reception sensor head 14b. ] Means that when the workpiece is detected, it changes complementarily. By averaging those values, the existence of the optical disk, which is a metal content, can be ensured without being affected by the edge of the sheet bundle 2. Can be determined. The graph shown in FIG. 3B shows the characteristics when a PMMA work is inserted, in which the installation distance is 100 mm and the insertion position is 30 mm.
[0039]
As is clear from the description of the various embodiments described above, the non-destructive inspection method of the present invention utilizes a microwave sensor to scan an article to be inspected with a microwave while reflecting or transmitting the reflected wave or transmitted light. It is to determine whether or not the article has the expected contents by receiving the wave and comparing the received wave output with the reference value. It does not need to be considered, and the device can be manufactured small and at low cost, so it can be easily installed in the narrow space of various production lines, and this type of non-destructive inspection method has become popular. Is a contributor.
[0040]
Note that the nondestructive inspection method of the present invention is expected to be applied not only to the above-described determination of the optical disk in the book, but also to various other applications. Specifically, detection of the presence or absence of metal parts in plastic parts, inspection of the presence or absence of an aluminum tag for theft prevention, detection of two sticks of rubber, detection of cream in pie dough, presence or absence or position detection through a conveyor, detection of wood gap position It can be applied to inspection of various articles in industry, such as detection, detection of dryness of paper, tobacco, tea, and fiber.
[0041]
【The invention's effect】
As is apparent from the above description, according to the nondestructive inspection method of the present invention, a microwave is used as a detection medium, and while an article to be detected is scanned with the microwave, the reflected or transmitted wave is received. It is to determine whether or not the intended contents are present in the article by comparing it with the received wave output reference value. Therefore, there is a danger such as when X-ray is used as a detection medium. There is no need to increase the size of the device, and there is no risk of being limited by the measurement distance as in the case of using a proximity sensor, and microwaves behave intricately in a substance, so they are not limited to metal objects. The presence or absence of various substances can be detected with high sensitivity, and nondestructive inspection can be performed on the contents of various materials.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a bookbinding line to which the present invention is applied.
FIG. 2 is an explanatory diagram showing main steps of a bookbinding line.
FIG. 3 is an explanatory diagram of a detection comparison test using a metal plate and a magazine.
FIG. 4 is an explanatory diagram of inspection by a microwave sensor.
FIG. 5 is a diagram showing an example of arrangement of a sensor head and a trigger sensor.
FIG. 6 is an explanatory diagram of a countermeasure against erroneous detection using a time gate.
FIG. 7 is an explanatory diagram of a countermeasure against erroneous detection using a timing gate.
FIG. 8 is an explanatory diagram of a countermeasure against erroneous detection using two receiving heads.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Conveyor 2 Sheet bundle 2a Sheet bundle of an adhesive adhesion part 3 Rotary cutter 4 Dust suction pipe 5 Adhesive layer 6 Adhesive dissolving layer 7 Endless conveyor 7a Binder 8 Cover bundle 9 Cover 10 Book bundle 11 Table 11a-11c Cutter blade 12 CD-ROM
12a, 12b 2 CD-ROM
13 Sensor Head 14 for Transmission 14 Sensor Head 14a for Receiving First Sensor Head 14b for Receiving Second Sensor Head 15 for Receiving Microwave Irradiation Axis 16 Trigger Sensor 17 Conveyor L Scan Line M Inspection Object MP Microwave Sensor Detection Positions P1, P4 Time points P11 and P14 at which the edge of the sheet bundle passes Edge times S1 to S4 of the edge of the sheet bundle Output TH of the microwave sensor Threshold value TP Trigger sensor detection position X Insertion direction

Claims (6)

While scanning the article to be inspected with microwaves, the reflected or transmitted wave is received, and the received wave output is compared with a reference value to determine whether or not the intended content exists in the article. A non-destructive inspection method characterized by determining. The non-destructive inspection method according to claim 1, wherein the scheduled contents are metal contents. The nondestructive inspection method according to claim 2, wherein when determining the presence or absence of the metal content, the received wave output when the scanning point crosses the edge of the article is excluded from the determination target. The nondestructive inspection method according to claim 2, wherein the article is a book, and the metal content is an optical recording medium such as a CD or a DVD. By scanning the book with microwaves using a microwave sensor, receiving a reflected wave or a transmitted wave and comparing the received wave output with a reference value, the expected metal content exists in the book. A non-destructive inspection method for determining whether to perform
When the place where the metal content should exist in the book coincides with the scanning point of the microwave sensor, it is arranged at a predetermined distance from the microwave sensor so that the scanning point coincides with the edge of the book. A synchronous sensor,
The microwave sensor determines the presence or absence of the metal content by comparing a reception output obtained in synchronization with the edge detection timing of the synchronization sensor with a reference value. Destructive inspection method. By scanning the microwave with the microwave sensor on the book, receiving the reflected wave or the transmitted wave, and comparing the received wave output with the reference value, the metal contents scheduled in the book are scheduled A non-destructive inspection method for determining whether a given number exists,
During a period in which the scanning point of the microwave sensor scans a place where the metal content should exist in the book, the scanning point is arranged at a predetermined distance from the microwave sensor so that the scanning point is continuously present on the book. Gate sensor,
The microwave sensor determines whether a predetermined number of metal contents exist in the book based on the number of times the reception output obtained during generation of the detection output of the gate sensor exceeds or falls below a reference value. A non-destructive inspection method characterized by determining whether or not the inspection is performed.

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