JP5623197B2 - Weighing device - Google Patents

Description

  The present invention relates to a weighing device that detects an article conveyed by a conveying means with an X-ray detection unit and measures the weight of the article at a timing based on an X-ray detection signal of the X-ray detection unit, and in particular, an X-ray detection unit. The present invention relates to a weighing apparatus that can weigh a weight at the most suitable measurement timing corresponding to the product type by using an X-ray detection signal output from the X-ray detector.

  The article inspection apparatus described in Patent Document 1 below is detected by a transport unit that transports an object to be inspected, a carry-in sensor 4 that detects a front part and a rear part in the transport direction of the test object, and the carry-in sensor 4. Quality determination means for obtaining quality data of the inspected object and determining the quality of the inspection object based on the quality data; and the inspection object in the transport direction based on a detection time by the carry-in sensor 4 The inspection object length calculation means 8a for calculating the length L of the object and the statistical means 9a for calculating the statistic relating to the inspection object length L are provided. According to this invention, based on the statistic calculated by the statistical means, the set length set in advance in the workpiece inspection apparatus to determine the reference time and the inspection object length of the inspection object actually being transported By comparing the length with which the distribution is concentrated, it is possible to take measures to achieve appropriate inspection accuracy and inspection efficiency.

JP 2008-297119 A

  In the conventional article inspection apparatus disclosed in the above-mentioned Patent Document 1, when the type of the object to be inspected is different and the shape is different from what was planned, when the object to be inspected is detected by the carry-in sensor. The detection sensitivity may vary. That is, the carry-in sensor has a threshold with respect to the signal level obtained when the object to be inspected interrupts the optical path, and outputs an ON or OFF detection signal to the outside depending on whether the signal level exceeds the threshold. It is like that. Therefore, when the shape of the inspection object to be detected by such a carry-in sensor changes from the intended one, the signal level obtained also varies, so that the detection signal is stable at a certain threshold value. It may not be obtained and the detection sensitivity may vary.

  In addition, even if the type and size of the object to be inspected are as expected, if the installation conditions such as the sensor installation position and orientation change for some reason, the height and direction of the optical path from the sensor will change, and the object to be inspected will change. There may be a case where the detection sensitivity of an object also varies.

  Therefore, conventionally, in the sensor provided in such an article inspection apparatus, the threshold value can be arbitrarily set by the volume provided in the sensor itself, and the type of the object to be inspected is the intended one. If there is a change in the external shape or the sensor installation state has changed, adjust the volume of the sensor on the user side as appropriate. The threshold value was reset so that detection sensitivity could be obtained.

  However, if the user cannot adjust the volume of the sensor well and the threshold setting is inappropriate, there is a problem in that the object to be inspected cannot be detected well and measurement cannot be performed. In addition, there is a case where the user unnecessarily adjusts the sensor volume for some reason. In such a case, the setting of the threshold value is inappropriate, and the detection of the inspected object does not go well. In a weight sorter that is a kind of article inspection apparatus, it is conceivable that the timing of weight measurement is inappropriate for the object to be inspected and the weighing accuracy deteriorates.

  Moreover, in the weight sorter, there are generally various types of articles of interest, and the shapes are also various. Even for the same workpiece, the size of the area in contact with the conveyance surface of the conveyance means of the inspection object conveyed by the conveyance means may be different or may not be conveyed in a certain direction. When such a workpiece is to be inspected, setting the detection level to obtain a timing signal for inspecting an article with a sensor is considered to be an important issue in order to achieve the purpose of inspection most reliably. The conventional sensor for detecting an article lacks a means for arbitrarily setting the optimum weighing timing corresponding to the article type, and therefore the weight measurement position of the article is not stable, and the weight with high accuracy is not necessarily required. There was also a problem that the measurement could not be performed.

  The present invention has been made in view of the above problems. In the weighing device 1 that detects an article to be carried into a weighing conveyor and measures the weight of the article on the weighing conveyor based on the loading detection timing, the article is provided. It is an object of the present invention to accurately detect the carry-in of the product onto the weighing conveyor and guarantee the weighing accuracy and certainty of the weight of the article.

  The weighing device 1 according to claim 1 detects an article W carried into the weighing conveyor 4 and measures the weight of the article conveyed on the weighing conveyor at a measurement timing determined based on the carry-in detection timing. The weighing apparatus 1 includes an X-ray generator 7 and an X-ray detector 8, and the X-ray detector is turned into an X-ray by passing the article W between the X-ray generator and the X-ray detector. An X-ray detection unit 6 that outputs an X-ray detection signal corresponding to the amount of transmission, and a gray level detection level signal that indicates an X-ray absorption level that increases or decreases according to the thickness of the article is generated from the X-ray detection signal. Detection level signal generation means 14 and load area signal generation means 13 for generating a load area signal indicating the load area of the article in the conveying direction on the weighing conveyor as the carry-in detection timing based on the detection level signal. And Serial load area signal generating means is characterized in that a control unit 11 for setting a threshold for the detection level signal to obtain a 該荷 heavy domain signal.

  The weighing device according to claim 2 is a weighing device according to claim 1, wherein the control unit determines whether the weight of the weighed article is within a predetermined weight range. The determination means 17 is provided.

  The weighing device 1 described in claim 3 is the weighing device 1 according to claim 1 or 2, wherein the control unit determines whether or not the measurement timing is within a preset effective period range. It is characterized by having a timing judgment means 18 for judgment.

  According to a fourth aspect of the present invention, in the weighing apparatus 1 according to the second aspect, the weight determination unit is configured so that the weight of the article is determined when the measurement timing is within a preset effective period range. It is characterized by determining whether or not is within a predetermined weight range.

  A weighing device according to a fifth aspect is the weighing device according to the fourth aspect, wherein the measuring device stores the detection level signal and the threshold set for the detection level signal, and the storage device stores the threshold. The display unit 31 displays the detection level signal and the threshold value.

  The weighing apparatus according to claim 6 is the weighing apparatus according to claim 5, wherein the weighing signal obtained from the weighing of the article based on the load area signal is stored in the storage means. A signal and the threshold value are stored in association with each other, and the display unit displays the measurement signal, the detection level signal, and the threshold value in association with each other.

  The weighing apparatus 1 described in claim 7 is characterized in that, in the weighing apparatus 1 according to claim 5, the threshold value is stored in the storage unit in correspondence with the type of the article.

  The weighing device 1 according to claim 8 is the weighing device 1 according to any one of claims 1 to 7, wherein the control unit applies to the article based on an X-ray detection signal from the X-ray detection unit. It is characterized by having foreign matter determination means 19 for determining whether or not foreign matter is mixed.

  According to the weighing device of the first aspect, the article W to be conveyed passes between the X-ray generator and the X-ray detector, and the X-ray according to the X-ray transmission amount output from the X-ray detector. An area in which a gray level detection level signal indicating an X-ray absorption level that increases or decreases according to the thickness of the article is generated from the line detection signal, and the load of the article on the weighing conveyor is applied to the weighing conveyor with respect to the detection level signal By setting a threshold value so as to be (contact area), it is possible to reliably and appropriately generate a load area signal as a carry-in detection timing. It is possible to carry out an article weighing that can guarantee the weighing accuracy and certainty of the weight. Furthermore, since the load region signal is generated from the detection level signal, the threshold value is set for the level signal whose concentration value indicates the amount of absorption by the substance in a straight line, making it easier to set the threshold value.

  According to the weighing device described in claim 2, in addition to the effect of the weighing device according to claim 1, weight determination means for determining whether or not the weight of the weighed article is within a predetermined weight range. Therefore, the inspection of the weight range can be executed with respect to the weight of the article obtained by accurately detecting the delivery of the article onto the weighing conveyor.

  According to the weighing device described in claim 3, in addition to the effect of the weighing device according to claim 1, it is determined whether or not the measurement timing determined by the load region signal is within a preset effective timing range. Therefore, it is determined whether the measurement timing for measuring the weight of the loaded article is appropriate or inappropriate based on the load region signal timing that allows appropriate weighing according to the response performance of the article W carried into the weighing conveyor. Can do.

  According to the weighing device of the fourth aspect, in addition to the effect of the weighing device of the second aspect, whether the determination means is within the weight range when the measurement timing is within the preset effective timing range. Since the determination is made as to whether or not the measurement timing is inappropriate and the reliability cannot be guaranteed, the highly reliable weight range inspection can be executed by excluding the article from the inspection target.

  According to the weighing device of the fifth aspect, in the effect of the weighing device according to the first aspect, the detection level signal and the threshold value set for the detection level signal are stored in the storage unit and displayed later if necessary. Can be displayed.

  According to the weighing device of the sixth aspect, in the effect of the weighing device according to the fifth aspect, the weighing signal obtained from the weighing of the article performed based on the timing signal is converted into the detection level signal and the threshold value. The measurement signal, the light reception level signal, and the threshold value can be associated with each other and displayed on the display unit later if necessary.

  According to the weighing device of the seventh aspect, in the effect of the weighing device of the fifth aspect, the threshold value is stored in correspondence with the type of the article, so that the detection level signal having a different waveform depending on the type of the article. It can be stored in correspondence with.

  According to the weighing device described in claim 8, in addition to the effect of the weighing device according to claim 1, it is determined whether or not foreign matter is mixed in the article based on the X-ray detection signal from the detection unit 6. Therefore, the X-ray detection signal corresponding to the X-ray transmission amount output from the X-ray detector can be used not only for the measurement of the weight of the article but also for the contamination inspection, and a wider inspection can be executed.

It is a block diagram which shows typically the structure of embodiment of this invention. It is a perspective view which shows the structure of the conveyance means and X-ray detection part in embodiment of this invention. (1) (a)-(c) is a figure which shows a state where an article is loaded on a weighing conveyor, (2) (a), (b) is a figure which shows the relationship between a measurement signal and an article. (A) is a figure which shows the 1st specific shape of the articles | goods applied to the weighing | measuring apparatus of embodiment of this invention, and the apparatus, (b) is the detection level signal and threshold value 1 which are obtained by the structure of (a). 2 is a waveform diagram showing respective outputs at threshold values 1 and 2. FIG. (A) is a figure which shows the 2nd specific shape of the articles | goods applied to the weighing | measuring apparatus of embodiment of this invention, and the apparatus, (b) is a detection level signal and threshold value which are obtained with the structure of (a). Waveform diagrams showing outputs at 1 and 2, and threshold values 1 and 2, (c) is a weighing signal output from the weighing device. (A) is a figure which shows the case where the articles | goods of the specific shape shown in FIG. 5 are conveyed upside down, and weighed, (b) is the detection level signal and threshold value 1 which are obtained with the structure of (a), and 2 and a waveform diagram showing respective outputs at the threshold 1 and the threshold 2, and (c) is a weighing signal output from the weighing device.

FIG. 1 is a configuration diagram of a weighing device 1 according to an embodiment of the present invention.
This weighing device 1 includes an introduction conveyor 3 and a weighing conveyor 4 that are driven in the same direction by a driving means 2 (drive motor) as conveying means for conveying the article W. The introduction conveyor 3 is a belt conveyor that accepts articles W carried from an adjacent line (not shown), conveys them, and delivers them to the adjacent weighing conveyor 4. The weighing conveyor 4 is attached to the weighing means 5 and is a belt conveyor for weighing the weight by the weighing means 5 while conveying the articles W received from the introduction conveyor 3.

  As shown in FIG. 2, the introduction conveyor 3 has an X-ray generator 7 disposed above the introduction conveyor 3 and an X-ray generator 7 disposed opposite to the introduction conveyor 3 with a conveyance belt interposed therebetween. An X-ray detector 6 composed of a line detector 8 is provided.

  The X-ray generator 7 is configured as a metal box, and has a cylindrical X-ray tube 9 immersed in insulating oil (not shown) inside. X-rays are generated by irradiating an anode target with an electron beam. The X-ray tube 9 is arranged so that the longitudinal direction thereof is the conveyance direction of the article W (the left-right direction in the figure). The X-rays generated by the X-ray tube 9 are substantially directed from the irradiation port toward the lower X-ray detector 8 from the irradiation port whose longitudinal direction is the direction perpendicular to the transport direction formed on the upper surface of the transport space S by a slit (not shown). A triangular screen is formed so as to cross the conveying direction.

  The X-ray detector 8 has a plurality of detection elements arranged in a straight line in the Y direction orthogonal to the transport direction on the plane in the transport direction (X direction) of the article W to be transported. Specifically, the X-ray detector 8 includes a photodiode (not shown) as a plurality of detection elements arranged in a line and a scintillator (not shown) provided on the photodiode. And a line sensor (not shown). Further, the X-ray detector 8 has an A / D converter (not shown). The A / D converter converts the luminance value data from the photodiode into digital data, and converts the X-ray detection signal into the digital data. It is designed to output.

  Instead of the X-ray detector 8 having an A / D converter, the controller 11 may have an A / D converter. That is, the luminance value data from the photodiode may be output as an analog detection signal, and the analog detection signal may be A / D converted and converted to digital data on the control unit 11 side. Further, the analog detection signal may be used as an X-ray detection signal as it is without performing A / D conversion on the control unit 11 side.

  The weighing means 5 is a load sensor that supports the weighing conveyor 4 and outputs a weighing signal based on the load of the article W. The weighing means 5 includes a scale mechanism such as an electromagnetic balance mechanism, and the article W is conveyed on the weighing conveyor 4. The load applied during the time is measured. The weighing means 5 may be a scale mechanism that can measure the weight, and may be constituted by a scale mechanism such as a differential transformer mechanism or a strain gauge mechanism.

  As shown in FIG. 1, the weighing device 1 is provided with a leakage prevention cover 10 so as to surround the upper space of the introduction conveyor 3 and the weighing conveyor 4, and X-rays other than the carry-in port and carry-out port for the article W are provided. X-rays irradiated from the generator 7 are shielded.

  As shown in FIG. 1, the weighing apparatus 1 includes a control unit 11, an input unit 21 for giving the control unit 11 necessary instructions and information, and a display unit 31 for outputting information processing results and the like to the outside. Is further provided. The control unit 11 stores a CPU that is the center of information processing activities for control in the apparatus 1 and storage of various programs for executing information processing procedures in the CPU and information necessary for information processing. The image processing means 12 and the determination means 16 are provided.

  The controller 11 controls the drive motor described above to convey the article W. In addition, when the transported article W is detected by the X-ray detector 6 and received detection information (X-ray detection signal), when the article W starts to be placed on the weighing conveyor 4 and finishes being transferred. Is generated and output to the weighing means 5 so that the weight of the article W can be accurately weighed.

  The image processing unit 12 includes a load region signal generation unit 13 and a detection level signal generation unit 14, and stores an X-ray image of the article W obtained from the X-ray detection signal output from the X-ray detection unit 6 as a digital image. The image is stored in the means 15 and the X-ray image is processed. This X-ray image is sampled in the transport direction at a sampling pitch substantially equal to the sampling pitch on one line by the X-ray line sensor, and imaged as an X-ray image. This X-ray image may be either an X-ray transmission image or an X-ray absorption image, but the X-ray absorption image whose density value indicates the amount of absorption by the substance in a straight line is emphasized or detected with a higher X-ray absorption rate Therefore, an X-ray absorption image is preferable.

For example, if the X-ray absorption rate of the substance is α and the thickness of the substance is L, the intensity S ′ after the X-ray having the intensity S is transmitted through the substance is theoretically S ′.
= S · exp (-α · L). If transformation is performed by taking the logarithm of both sides, it can be written as α · L = log (S) −log (S ′). The X-ray transmission image corresponds to the two-dimensional distribution of S ′, and if it is transformed by taking the logarithm as described above, it is obtained by converting it into an X-ray absorption image showing a two-dimensional cloth having an absorption amount α · L by the substance. Can do.

  The image processing means 12 performs image processing such as a filter that emphasizes foreign object information to be detected and extracts it as a foreign substance extraction image based on preset parameters, and detects the presence or absence of foreign substances mixed in the article W. It is like that. For example, a feature extraction filter such as a differential filter (Roberts filter, Prewitt filter, Sobel filter) or a Laplacian filter is used as a filter for enhancing foreign matter information.

  The detection level signal generation unit 14 obtains the amount of X-rays absorbed by the article W from the amount of X-ray transmission of the X-rays transmitted through the article W based on the above-described equation for conversion into an X-ray absorption image. A gray level detection level signal is generated from an X-ray image in which the state without W is 0 level. This detection level signal sequentially generates a peak value or an average value of the light and dark levels in the width direction of the introduction conveyor along the conveyance of the article W.

  Further, the generated detection level signal is delayed by a delay time Td determined from the distance D from the article detection position by the X-ray detection unit 6 to the carry-in side tip of the weighing conveyor 4 and the conveyance speed V of the introduction conveyor 3, and will be described later. The load area signal generated through the processing described later is sent to the weighing means 5, and the weighing means 5 measures the weight of the article W being conveyed by the weighing conveyor 4. The measurement result is displayed on the display unit 31 as necessary.

  Further, the detection level signal generation means 14 can also execute a filtering process to generate a detection level signal from the X-ray image. For example, when the X-ray detection signal output from the X-ray detection unit 6 includes a lot of noise, a detection level signal is generated from the X-ray image after executing a filter for reducing noise such as smoothing.

  Furthermore, when the detection level signal is generated by the detection level signal generation unit 14, if there is a foreign object in the foreign object extraction image, the detection level is increased by the foreign object. Processing is performed such that the detection level signal is generated by not using the X-ray image at the existing position or by replacing the X-ray image with the gray level of the X-ray image without the foreign object around the position where the foreign object exists. As a result, the influence of the foreign matter is eliminated, and the detection level signal for the article W becomes more reliable. For example, in the case of an article whose contents are packaged in a bag having a seal portion as shown in FIG. 4A (for example, food in a bag), the detection level of the seal portion is detected even if there is a foreign object in the seal portion. It is possible to make the level of the seal portion without increasing the height.

  The processing for removing the influence of the foreign matter from the detection level signal is performed when the detection level signal is generated from the X-ray image. However, after the detection level signal is generated from the X-ray image, the foreign matter in the detection level signal is generated. Processing may be performed in which the detection level (value) of the position where the is present is replaced before and after.

  The load area signal generation unit 13 generates a load area signal indicating the load area of the article W in the conveyance direction from the detection level signal based on the threshold value input from the input unit 21 or the threshold value stored in the storage unit 15. Normally, when the weighing device is in the timing adjustment state with respect to the article to be weighed, a load region signal is generated using the threshold value from the input unit 21, and when it is in the operating state, it is stored in the storage unit 15. A load region signal is generated using the threshold value.

  The determination unit 16 includes a weight determination unit 17, a timing determination unit 18, and a foreign matter determination unit 19, and the weight determination unit 17 determines the weight of the weighed article from the upper and lower limits of the weight set from the input unit 21. Judges whether the weight is within the range specified by the limit. When the weight is within the specified weight range, it is determined that the weight exceeds the upper limit, and when the weight exceeds the lower limit, the weight is determined as NG, and when the weight is lower than the lower limit, the weight is determined as NG.

  The timing determination means 18 determines whether or not the measurement timing for measuring the weight of the article W, which will be described later, is within the timing range set from the input unit 21 (within the effective period range), and the determination result is the timing NG. Is displayed on the display unit 31. More specifically, for example, the estimated time obtained by adding the waveform delay time of the filter after the article W has been loaded on the weighing conveyor 4 and the conveyance has been stabilized after the article W has been loaded on the weighing conveyor 4 is within the allowable range. When the minimum value, the movement time of the article W to the rear end of the weighing conveyor 4 is set as the maximum value of the allowable range, and the measurement timing is out of the allowable range, a stable measurement value cannot be obtained, so it is determined as a timing failure Is done. In addition, when the timing determination unit 18 determines that the timing is poor, the weight determination unit 17 described above does not determine the weight range because the weight of the article W is measured in an unstable state. It is preferable to make it.

  The foreign matter determination unit 19 determines whether there is a foreign matter in the foreign matter extraction image obtained by the image processing unit 12, and the determination result is displayed on the display unit 31.

  Next, the timing for measuring the load in the weighing means 5, that is, the timing for weighing the article W will be described. 3A shows a state in which the article W starts to be transferred onto the weighing conveyor 4, FIG. 3B shows a state in which the article W has been transferred onto the weighing conveyor 4, and FIG. Shows a state of being conveyed on the weighing conveyor 4 after being transferred onto the weighing conveyor 4. When the article W starts to be transferred onto the weighing conveyor 4 as in (a), the load of the article W starts to act on the weighing conveyor 4 and the level of the weighing signal increases. Then, as shown in (b), a predetermined conveyance stabilization time (T2) is expected after the article W is completely transferred to the weighing conveyor 4 until the shaking of the article W is settled. Furthermore, when the waveform delay time (T3) corresponding to the time constant of the low-pass filter that attenuates noise, which is an unnecessary AC component, elapses from the weighing signal after the conveyance of the article W is stabilized, the weighing signal becomes stable and accurate. The article W can be weighed well.

  Here, it is the time (T1) from when the article W starts to be transferred to the weighing conveyor 4 to when it is completely transferred to the weighing conveyor 4, and T1 is an area in the conveyance direction in which the article W is in contact with the belt surface of the weighing conveyor 4 ( Length) and the speed of the weighing conveyor 4.

  The timing T for measuring the weight of the article W when weighing the article W stably and accurately is shown in (a) of FIG. 3 (1), as shown in (b) of FIG. 3 (1). This is the time from the start of the transfer of the article W onto the weighing conveyor 4 to the timing of starting the weighing of the article W, and is T1 + T2 + T3. Then, the weight of the article W is measured by sampling the TW for a predetermined period after T and calculating a measured value (measurement timing). The sampling at this time may be performed for a predetermined period after the waveform delay time ends, or a period until the article W reaches the rear end of the weighing conveyor 4 (a period obtained by subtracting T from TE). You may carry out. Furthermore, when the sampling period can be secured for a predetermined period, the attenuation performance of the low-pass filter may be strengthened to further attenuate the noise, and then sampling may be performed.

  In the control unit 11 of the present embodiment, the weight of the article W is measured as the carry-in detection timing using a detection level signal indicating the X-ray absorption level of the article W generated from the X-ray detection signal output from the X-ray detection unit 6. A load region signal is generated as a basis for determining the measurement timing for the measurement. This load area signal is a signal that assumes the load area of the article W in the conveying direction (area where the article is in contact with the belt surface of the conveyor). In order to obtain this load area signal from the detection level signal, a threshold ( Detection level) can be set arbitrarily. This threshold value is input from the input unit 21 by the user and stored in the storage unit 15, and becomes data used for information processing every time an X-ray detection signal is input from the X-ray detection unit 6. It is desirable to predetermine for each product type according to the waveform of the detection level signal generated from the X-ray detection signal from the X-ray detection unit 6 that varies depending on the product type of the article W.

  That is, the X-ray detection unit 6 of the present embodiment outputs an X-ray detection signal corresponding to the X-ray transmission amount of the X-ray that has passed through the article W, and the waveform of the detection level signal based on the X-ray detection signal is the article. It takes a specific form according to the outer shape of W. For example, as shown in FIG. 4 (a), when the article W is an article (for example, food in a bag) whose contents are packaged in a bag having flange-shaped pieces at the front and rear, X-rays are used. The detection level signal based on the X-ray detection signal obtained when the article W passes through the detection unit 6 is, for example, a detection level signal having a waveform as shown in the upper part of FIG.

  Of the detection level signal, the amount of X-rays absorbed by the article W is small in the part corresponding to one part of the front and rear packaging, and the article is absorbed by the article W because the X-ray is transmitted through the contents in the central part. The absorbed amount of X-rays is greatly stable as compared with a piece of packaging.

  In order to reliably detect the article W from such a detection level signal, in order to determine the measurement timing for measuring the weight of the article W as a carry-in detection timing by thresholding the detection level signal with any threshold value The problem is whether to obtain the load region signal of the signal that is the basis of the above. In this example, two relatively low threshold values 1 and two relatively high threshold values 2 were examined as shown in the upper part of FIG. Here, since the low threshold value 1 overlaps the unstable portion of the signal caused by the one part before and after the article W, the output of the threshold value 1 shown in the middle part of FIG. It may not be appropriate. Further, in many parts where the detection level signal is low, the article W is not in contact with the belt surface of the conveyor. On the contrary, when the high threshold 2 is used, the stable portion of the detection level signal is used. Therefore, the output of the threshold 2 shown in the lower part of FIG. Since W seems to be almost in contact with the belt surface of the conveyor, it is considered more preferable for reliable detection of the article W.

  Therefore, in the present embodiment, when an article W having a form as shown in FIG. 4A is targeted, this is conveyed in advance by the weighing device 1 and passed through the X-ray detection unit 6, and the detection level thereof. It is desirable to obtain a signal and store a detection level signal based on the signal in the storage unit 15 of the control unit so as to be usable. Thereafter, when setting the threshold value, as shown in the upper part of FIG. 4B, this detection level signal is displayed on the screen of the display means 31, and the input unit 21 is further operated to display the threshold value. The most appropriate value is set in comparison with the detection level signal displayed above. If an appropriate value can be set, it is confirmed and stored in the storage means 15 or the like so that it can be used for control.

  If the threshold value is set as described above, when the article W as shown in FIG. 4A is weighed by the weighing device 1, every time the article W is transported and passes through the X-ray detection unit 6. A detection level signal as shown in the upper part of FIG. 4B is obtained, and this is processed with the threshold value 2 in the control unit 11 so that the article W is detected without error in a stable manner most suitable for the shape of the article W. Then, a load area signal (output of threshold value 2) as shown in the lower part of FIG. 4B is generated, and the weighing means 5 is operated at a timing based on this load area signal, and the article W is appropriately weighed. Accordingly, the article W can be weighed by the weighing means 5 at an optimal timing after the article W has been transferred from the introduction conveyor 3 to the weighing conveyor 4, and high-precision weighing can be performed in a state where vibrations and the like are attenuated.

  In addition, although the threshold value is set as described above and the intended product W is targeted, the threshold value is not actually set appropriately, so the timing signal is inappropriate and the weighing of the product W is not possible. There may be a case where it is not performed at an appropriate timing. For example, the measurement timing is inappropriate, and the measurement has been performed while the article W has just been transferred to the weighing conveyor 4 and the vibration of the article W has not been settled. In such a case, if the detection level signal of the article W stored in the storage unit 15 or the like and the set threshold value are displayed on the display unit 31 again by the control unit, the load region signal is obtained from the detection level signal. It is possible to easily review visually whether or not the threshold value set for obtaining was appropriate. If it is determined that it is not appropriate, an appropriate threshold value may be set while visually recognizing the detection level signal on the display unit 31 and stored again in the control unit 11.

5 to 6 are diagrams showing other examples in which threshold values are set for other varieties having different varieties and external shapes from the article W shown in FIG.
As shown in FIG. 5 (a), when the article W is an article having a box-shaped main body with a pointed triangular tip and a flange-shaped piece at the tip (for example, a side-by-side milk pack). The detection level signal obtained from the X-ray detection signal when the article W passes through the X-ray detection position of the X-ray detection unit 6 has a waveform as shown in the upper part of FIG. That is, the detection level signal gradually increases at the portion corresponding to the front end side of the article W, and thereafter becomes stable.

  Here, as in the example of FIG. 4, considering the relatively low threshold 1 and the relatively high threshold 2, when the low threshold 1 is used, the front portion of the article W is detected early. However, since the portion is a portion that is not in contact with the belt surface and is a thin piece portion, the detection of the output of the threshold value 1 shown in the middle part of FIG. In addition, when the high threshold 2 is used, the detection is delayed, but the output of the threshold 2 shown in the lower part of FIG. It may be more preferable for reliable detection of the article W. Which threshold is selected depends on the part of the article W that is most suitable for detection in consideration of various circumstances such as the shape of the article W, and the result of actually carrying and weighing. It can be determined in consideration of the above.

  FIG. 6 is a diagram showing a case where the article W having a specific shape shown in FIG. According to the present embodiment, not only the above-described threshold setting for shape confirmation but also the threshold setting can be performed in response to the detection of the change in the posture of the article W.

  As shown in FIG. 6, when an article W having a shape as shown in FIG. 5 is conveyed in the opposite direction to FIG. 5, it cannot be determined that the article W is in the opposite direction when the threshold value is one. . However, according to the present embodiment, since the two threshold values 1 and 2 are provided at appropriate levels corresponding to the shape of the detection level signal corresponding to the characteristic shape of the article W, the directions are reversed. Can be determined. That is, if the case of FIG. 5 described above is a normal or normal case, in this case, after the output is turned on for the threshold value 1 as shown in FIG. The load on the conveyor 4 starts and the weighing signal rises. The outputs for the threshold values 1 and 2 are simultaneously turned OFF. However, in the case of FIG. 6, the outputs are turned on almost simultaneously for the threshold values 1 and 2, and simultaneously, the load on the weighing conveyor 4 starts and the weighing signal rises. Then, after the output for threshold 2 is turned off, the output for threshold 1 is turned off. From the output of each threshold value and the form of the weighing signal, the control unit 11 allows the article to pass as being in the normal state in the case of FIG. 5, and changes the posture from the normal state in the case of FIG. It can be judged as NG and excluded from the line. In that case, the control unit 11 stores the reason for the excluded “posture change” or the like. Note that which direction is normal or NG may be the opposite of the above-described example, and may be determined according to the purpose of the inspection in the line and other conditions.

  In addition, when the article W is transported horizontally, transported vertically, transported in layers, etc., a threshold for detecting each situation and a determination method using this are individually set and dealt with. By leaving the memory in that case, the reliability as the weighing device 1 is improved.

  Further, in the weighing device 1 of the present embodiment, a predetermined stabilization time has elapsed after the article W has been transferred onto the weighing conveyor 4, and the waveform of the weighing signal that is output with reduced vibration due to the transfer of the article W is constant. From the viewpoint of measurement accuracy, it is necessary to sample the measurement signal as a measurement value after the value has settled. In the weighing device 1 of the present embodiment, the measurement timing for weighing the optimum weight of the article W can be optimally determined by setting an appropriate threshold value. For example, in the example shown in FIGS. 5 to 6 described above, the threshold value 1 is relatively low for the purpose of detecting that the article W has not been transferred to the weighing conveyor 4 but has entered the area of the weighing conveyor 4. The threshold value 2 is set to a value that is ON, and the threshold value 2 is a value for determining the measurement timing along with the detection of the article W that has been transferred to the weighing conveyor 4, so that the threshold value 2 is set to a value that is ON at a relatively high level. It is set. In FIGS. 5 and 6, the load region signal having the above-described T <b> 1 is defined from the time when the output based on the threshold values 1 and 2 is turned ON until the time when the output value of the threshold 2 is turned OFF. The timing T at which the weighing of the article W is started is obtained, and the measurement timing for weighing the article W is determined. Thus, the threshold value 2 for indirectly setting the measurement timing can be set at an appropriate level corresponding to the shape of the detection level signal corresponding to the characteristic shape of the article W.

  Furthermore, in the weighing device 1 of the present embodiment, when the weighing means 5 operates at the measurement timing based on the carry-in detection timing signal (load region signal) generated by the thresholds 1 and 2, the response of the weighing means 5 is not in time. If the vibration waveform is not sufficiently focused on and the measurement cannot be performed accurately and properly (when the stable part of the detection level signal is short), the reliability of the measurement result cannot be guaranteed, so the measurement timing is unsuitable. Is preferably discharged as

  For this purpose, the determination unit 16 includes the timing determination unit 18 as described above, and determines whether the measurement timing is appropriate or inappropriate. More preferably, a timing effective range as a timing at which appropriate weighing can be performed is stored in consideration of different shapes depending on the type of the article W.

  On the other hand, since the presence or absence of foreign matter based on the X-ray detection signal of the X-ray detection unit is irrelevant to the response performance of the weighing means 5, whether or not the measurement timing determined by the load region signal is within the effective range. It is better to be judged regardless.

  When the measurement timing determined by the load region signal has a sufficient margin with respect to the response characteristic of the weighing means 5 (when the sampling period can be secured for a predetermined period), the weight is sampled by sampling the weighing signal. You may make it raise the precision of a weight by increasing sampling number and averaging. Instead of increasing the number of samplings, the characteristics of the low-pass filter applied to the measurement signal (for example, the cut-off frequency fc and the attenuation coefficient Q) are changed to increase the attenuation of the vibration component and further attenuate the noise. Sampling may be performed.

  As described above, various parameters such as a threshold, a timing effective range, and a weight determination condition are stored in the storage unit for each product type according to the type of the article W. However, the low-pass filter for stabilizing weighing and accurately weighing As for the characteristic parameters (cutoff frequency fc and attenuation coefficient Q), stored values may be updated as needed.

  In the weighing apparatus 1 of the present embodiment, the load region signal is generated from the detection level signal, but the load region signal is generated from the X-ray detection signal (X-ray transmission amount) output from the X-ray detection unit. You may make it do. Also in this case, a threshold value process is performed on the peak value or average value of the X-ray detection signal in the width direction X of the introduction conveyor 3 to generate a load region signal.

  In the weighing device 1 of the present embodiment, the X-ray generator 7 and the X-ray detector 8 are arranged on the introduction conveyor 3 so as to detect X-rays. You may arrange | position the X-ray generator 7 and the X-ray detector 8 in the position which detects an X-ray in the position where W changes.

  According to the weighing device 1 of the present embodiment, when the weight of the article W is weighed as described above, the measured value can also be stored in the storage unit 15 of the control unit 11 or the like. In this case, the storage unit 15 of the control unit 11 stores the weighing signal obtained from the weighing of the article W based on the load area signal, the detection level signal of the article W and the threshold value, as shown in FIGS. The information can be stored in association with a common time axis, and the stored contents can be displayed on the display unit 31 in the manner shown in FIGS. Therefore, while visually recognizing the detection level signal of the X-ray detection unit 6 for the actual article W, the currently set threshold values, and the actual waveform such as the weighing signal, the posture change as described above, an appropriate The threshold can be optimally set according to the purpose such as the measurement timing. Specifically, if the detection level signal is displayed on the display unit 31, the direction and orientation of the article W conveyed by the conveying unit can be easily recognized, and an appropriate threshold value can be easily set.

DESCRIPTION OF SYMBOLS 1 ... Metering device 3 ... Introduction conveyor as conveyance means 4 ... Measurement conveyor as conveyance means 5 ... Measurement means 6 ... X-ray detection part 7 ... X-ray generator 8 ... X-ray detector 11 ... Control part 12 ... Image processing Means 15 ... Storage means 16 ... Determination means 21 ... Input section 31 ... Display section

Claims (8)

In a weighing device (1) for detecting an article (W) carried into a weighing conveyor (4) and weighing the weight of the article conveyed on the weighing conveyor at a measurement timing determined based on the carry-in detection timing,
An X-ray generator (7) and an X-ray detector (8) are provided, and when the article (W) passes between the X-ray generator and the X-ray detector, the X-ray detector becomes X An X-ray detector (6) that outputs an X-ray detection signal corresponding to the amount of transmitted radiation;
A detection level signal generating means (14) for generating a detection level signal of a gray level indicating an X-ray absorption level that increases or decreases according to the thickness of the article from the X-ray detection signal;
Load region signal generating means (13) for generating a load region signal indicating a load region of the article in the conveying direction on the weighing conveyor as the carry-in detection timing based on the detection level signal, and the load region signal A measuring device (1) comprising: a control unit (11) for setting a threshold value for the detection level signal so that the generating means obtains the load region signal The weighing apparatus according to claim 1, wherein the control unit includes weight determination means (17) for determining whether or not the weight of the weighed article is within a predetermined weight range. The weighing apparatus according to claim 1 or 2, wherein the control unit includes timing determination means (18) for determining whether or not the measurement timing is within a preset valid period range.   The weight determination unit determines whether the weight of the article is within a predetermined weight range when the measurement timing is within a preset effective period range. The described weighing device A storage unit (15) for storing the detection level signal and the threshold value set for the detection level signal; and a display unit (31) for displaying the detection level signal and the threshold value stored in the storage unit. The weighing device according to claim 1, wherein the weighing device is characterized in that   The storage means stores a measurement signal obtained from the measurement of the weight of the article based on the load area signal, in association with the detection level signal and the threshold value, and the display unit stores the measurement signal. 6. The weighing apparatus according to claim 5, wherein a signal, the detection level signal, and the threshold value are displayed in association with each other. 6. The weighing apparatus according to claim 5, wherein the threshold value is stored in the storage unit in association with the type of the article. The said control part has a foreign material determination means (19) which determines whether the foreign material is mixed in the said article | item based on the X-ray detection signal from the said X-ray detection part. 8. The weighing device according to any one of items 7.

Images