Packaging bag thickness measurement device

Abstract

To measure the thickness of a packaging bag without applying pressure thereto.SOLUTION: When a packaging bag 10 that contains multiple food products 16 stacked randomly in the vertical and horizontal directions, which has been manufactured by a vertical bag manufacturing, filling, and packaging machine 20, is conveyed along a thickness measurement conveying path 30A, a thickness detection unit 32 irradiates an upper surface 11 of the packaging bag 10 being conveyed along the thickness measurement conveying path 30A with detection light L1. A thickness detection signal corresponding to the thickness of the packaging bag 10 is generated on the basis of reflected light L2 reflected by the upper surface 11 of the packaging bag 10. A thickness measurement value of the packaging bag 10 is calculated for each packaging bag 10 by a thickness calculation unit 34B on the basis of multiple sampling data obtained by a sampling unit 34A for each packaging bag 10.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an apparatus for measuring the thickness of a packaging bag. [Background technology]

[0002] When a vertical form-fill-seal packaging machine is used to produce packaging bags containing multiple food items, such as snack foods, stacked randomly vertically and horizontally, the thickness of the packaging bag discharged from the vertical form-fill-seal packaging machine onto a conveying path is detected by a thickness measuring device arranged on the conveying path. Products whose thickness falls within the acceptable range are deemed to be acceptable products, and products whose thickness does not fall within the acceptable range are rejected as defective products. One such thickness measuring device is known in which a pressing member that is raised and lowered by the rotational driving force of a servo motor is provided above the conveying path, and the thickness of the packaging bag is detected based on the amount of rotation of the servo motor detected when the pressing member is lowered to press the top surface of the packaging bag (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-68915 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned conventional technology, if the volume of the packaging bag is large and there is sufficient space in the storage space for multiple foods that are randomly stacked vertically and horizontally, the multiple foods are likely to move within the storage space when a pressing force is applied to the top surface of the packaging bag from a pressing member. Therefore, when the pressing member presses the top surface of the packaging bag, the multiple food items stored in a random stack in the vertical and horizontal directions are subjected to a pressing force but are able to move within the storage space, so that portions of the top surface of the packaging bag are less likely to become locally pinched between the pressing member and the protrusions, corners or edges of the multiple foods. On the other hand, if the volume of the packaging bag is relatively small and there is not much room in the storage space of the packaging bag to accommodate multiple foods that are randomly stacked vertically and horizontally, the movement of the multiple foods will be restricted when a pressing force is applied to the top surface of the packaging bag from the pressing member. Therefore, when the pressing member presses the top surface of the packaging bag, the protrusions, corners and edges of the multiple foods that are stacked randomly in the vertical and horizontal directions are likely to abut against the top surface of the packaging bag from the inside, and part of the top surface of the packaging bag becomes pinched between the pressing member and the protrusions, corners and edges of the multiple foods, making it easy for a large pressing force to be applied locally to that part of the top surface of the packaging bag. As a result, there is a concern that pinholes may form in the upper surface of the packaging bag depending on the amount of pressure locally applied to the upper surface of the packaging bag, and some kind of improvement is required. The present invention has been devised in consideration of the above-mentioned circumstances, and an object of the present invention is to provide a packaging bag thickness measuring device that is advantageous for measuring the thickness of a packaging bag without applying a pressing force to the packaging bag. [Means for solving the problem]

[0005] In order to achieve the above-mentioned object, one embodiment of the present invention is a thickness measuring device for a packaging bag in which a plurality of food products produced by a vertical bag form fill and pack packaging machine are randomly stacked in the vertical and horizontal directions, and is characterized in that it comprises a thickness measurement conveying path that extends approximately horizontally and transports the packaging bag, a thickness detection unit that irradiates detection light onto an upper surface of the packaging bag transported on the thickness measurement conveying path and generates a thickness detection signal corresponding to the thickness of the packaging bag based on the detection light reflected by the upper surface of the packaging bag, a sampling unit that obtains a plurality of sampling data for each of the packaging bags by sampling the thickness detection signal at a predetermined period, and a thickness calculation unit that calculates a thickness measurement value of the packaging bag for each of the packaging bags based on the plurality of sampling data. In addition, one embodiment of the present invention is characterized in that a leveling conveying path is provided that is connected to the upstream end of the thickness measurement conveying path, and the leveling conveying path is provided with a vibration section that applies vibration to the multiple foods stacked and contained in the packaging bag to level the top surface of the packaging bag to an approximately flat surface. In addition, one embodiment of the present invention is characterized in that the calculation of the thickness measurement value by the thickness calculation unit is performed by identifying a maximum value among multiple sampling data obtained for each of the packaging bags. In addition, one embodiment of the present invention is characterized in that the thickness measurement value is calculated by the thickness calculation unit by calculating the arithmetic average of the top N (N is a natural number equal to or greater than 2) of multiple sampling data obtained for each packaging bag. In addition, one embodiment of the present invention is characterized in that the thickness measurement value is calculated by the thickness calculation unit by calculating a weighted average value weighted by the length along the conveying direction of the packaging bag from the top N (N is a natural number equal to or greater than 2) sampling data of multiple sampling data obtained for each packaging bag. In addition, one embodiment of the present invention is characterized in that it further includes a statistical data calculation unit that calculates statistical data based on the thickness measurement values ​​of the multiple packaging bags, and the statistical data includes at least one of a difference value between a maximum value and a minimum value of the thickness measurement values, an arithmetic mean value of the thickness measurement values, a standard deviation value of the thickness measurement values, and a trend graph showing the change tendency over time of at least one of the difference value, the arithmetic mean value, and the standard deviation value. Effect of the Invention

[0006] According to one embodiment of the present invention, a thickness measurement value of the packaging bag can be obtained without applying a pressing force to the top surface of the packaging bag. As a result, as in the conventional method, a pressing member presses against the top surface of the packaging bag, which causes a portion of the top surface of the packaging bag to be pinched between the pressing member and the protrusions, corners or edges of multiple foods that are randomly stacked in the vertical and horizontal directions and contained therein, and a large pressing force is not applied locally to that portion of the top surface of the packaging bag. This is advantageous in measuring the thickness of the packaging bag while reliably preventing pinholes from occurring in the top surface of the packaging bag. In addition, by using a vibration section provided on the leveling conveying path to vibrate multiple foods contained in a packaging bag and stacked randomly in the vertical and horizontal directions, the top surface of the packaging bag can be made almost flat and level, which suppresses fluctuations in the thickness detection signal corresponding to the top surface of the packaging bag generated by the thickness detection section, thereby being advantageous in reducing variation and error in the thickness measurement values ​​of the packaging bag calculated by the thickness calculation section and improving the accuracy of the thickness measurement values. Furthermore, if the thickness calculation unit calculates the thickness measurement value by identifying the maximum value among the multiple sampling data obtained for each packaging bag, a simple process of identifying the maximum value from the multiple sampling data is sufficient, which is advantageous in terms of quickly calculating the thickness measurement value by the thickness calculation unit, and therefore advantageous in terms of increasing the conveying speed of the thickness measurement conveying path and improving the efficiency of measuring the thickness of the packaging bag by the thickness measuring device. In addition, if the thickness calculation unit calculates the thickness measurement value by calculating the arithmetic average of the top N (N is a natural number greater than or equal to 2) of multiple sampling data obtained for each packaging bag, this is advantageous in suppressing variation in the thickness measurement value, and therefore is advantageous in improving the accuracy of the thickness measurement value. In addition, if the thickness calculation unit calculates the thickness measurement value by calculating a weighted average value weighted by the length along the conveying direction of the packaging bag from the top N (N is a natural number greater than or equal to 2) sampling data of multiple sampling data obtained for each packaging bag, this is more advantageous in ensuring the accuracy of the thickness measurement value. Furthermore, if the statistical data calculation unit calculates statistical data based on the thickness measurements of multiple packaging bags, including at least one of the following: a difference between the maximum and minimum thickness measurements, an arithmetic mean value of the thickness measurements, a standard deviation value of the thickness measurements, and a trend graph showing the change trend over time of at least one of the difference value, the arithmetic mean value, and the standard deviation value, then it is possible to accurately determine whether the functions and operations of the vertical form-fill-seal packaging machine are normal based on the statistical data, which is advantageous for accurately performing adjustment and maintenance work on the vertical form-fill-seal packaging machine and for improving the yield and quality of the packaging bags manufactured. [Brief description of the drawings]

[0007] [Figure 1] 1 is a side view showing a configuration of a packaging bag thickness measuring device according to an embodiment. [Diagram 2] 3 is a block diagram showing the configuration of a control system of the packaging bag thickness measuring device according to the embodiment; FIG. [Diagram 3] 10 is a side view showing the positional relationship between a packaging bag on a thickness measurement transport path and a thickness detection unit. FIG. [Figure 4] 1A is a graph showing the change in thickness detection signal over time, and FIG. 1B is a graph showing the change in sampling data over time. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, the packaging bag will be described. As shown in Figs. 1 and 3, in this embodiment, the packaging bag 10 is a single-package bag 10A in which a plurality of food items 16 are contained. As shown in FIG. 3, the packaging bag 10 consisting of a single-pack bag 10A is made up of a single bag body 12 in which a plurality of food products 16 are randomly stacked vertically and horizontally, and has a length, a width perpendicular to the length, and a thickness perpendicular to the length and width, and both ends in the longitudinal direction are sealed by seal portions 14. In this specification, multiple food items 16 may be stacked randomly vertically and horizontally and contained in packaging bag 10, and the shape and size of food items 16 are not particularly limited. Examples of such food products 16 include potato chips or popcorn in which each piece of food product 16 is of irregular size and shape, or cookies or candies in which each piece of food product 16 is formed to be the same or nearly the same size and shape. The packaging bag 10 is formed, for example, from an opaque packaging film, and as such a packaging film, an aluminum vapor deposition film having light blocking properties is used to prevent oxidation of food 16 such as snack foods.

[0009] As shown in Figures 1 and 3, the multiple foods 16 stored in the bag body 12 of the packaging bag 10 and stacked randomly in the vertical and horizontal directions are, for example, snack foods such as potato chips, but the type of food 16 stored is not limited. In addition, the vertical form-fill-seal packaging machine 20 stores air in the bag body 12 together with the foods 16, causing the bag body 12 to be inflated to a certain extent. This is to ensure the thickness of the bag body 12 with the air, thereby mitigating shocks during transportation and protecting the foods 16 stored in the bag body 12 and stacked randomly in the vertical and horizontal directions.

[0010] As shown in FIG. 1, a packaging bag 10 is produced by a vertical form-fill-seal packaging machine 20 by placing a plurality of food products 16 together with air in a bag body 12. In FIG. 1, reference numeral 20A denotes a horizontal sealing unit of a vertical bag making, filling and packaging machine 20, and the seal portion 14 of the packaging bag 10 is formed by the horizontal sealing unit 20A. The manufactured packaging bags 10 are then dropped from the vertical form-fill-seal packaging machine 20 toward a discharge chute 22 located below it and extending in an almost vertical direction, and are then discharged by the weight of the packaging bags 10 onto a discharge conveyor 24 that extends at a gentle slope from the discharge chute 22 and becomes higher the further downstream in the conveying direction. Here, the packaging bag 10 is discharged onto the discharge conveyor 24 so that the sealed portion 14 at one end of the length of the packaging bag 10 is located upstream in the conveying direction, and the sealed portion 14 at the other end of the length of the packaging bag 10 is located downstream in the conveying direction. In addition, since the packaging bags 10 are intermittently dropped from the vertical form-fill-seal packaging machine 20 into the discharge chute 22, each packaging bag 10 is transported at intervals in the transport direction on the discharge conveyor 24, the leveling conveyor 28 described below, the first transport conveyor 30, and the second transport conveyor 40. The discharge conveyor 24 is composed of a drive roller 2402 that is rotated by a motor not shown, a driven roller 2404, and a conveyor belt 2406 that is stretched around the rollers 2402, 2404 and transports the packaging bags 10 on its upper surface, and the transport speed of the discharge conveyor 24 is controlled to a predetermined speed.

[0011] As shown in FIG. 1, packaging bags 10 are discharged from vertical form-fill-seal packaging machine 20 toward discharge chute 22 with their length direction oriented vertically. As a result, the multiple food items 16 contained in the packaging bag 10 and stacked randomly vertically and horizontally move due to their own weight toward the sealing section 14 located at the bottom and are transported from the discharge chute 22 to the discharge conveyor 24 in an unevenly distributed state, so that on the discharge conveyor 24, the majority of the multiple food items 16 contained in the packaging bag 10 are unevenly distributed in the area near the sealing section 14 located downstream in the conveying direction. As a result, on the discharge conveyor 24, when viewed from a direction perpendicular to the conveying direction and the vertical direction, the majority of the multiple food items 16 are unevenly distributed and stacked randomly in the vertical and horizontal directions in the area of ​​the packaging bag 10 near the sealed portion 14 located downstream in the conveying direction, resulting in a large thickness of the packaging bag 10. On the other hand, in the portion of the packaging bag 10 near the sealed portion 14 located on the upstream side in the conveying direction, since there are almost no food products 16 present, the thickness of the packaging bag 10 becomes smaller. Therefore, when viewed from a direction perpendicular to the conveying direction and the vertical direction, the packaging bag 10 has a shape in which its thickness gradually decreases from the downstream side to the upstream side in the conveying direction; in other words, the packaging bag 10 has a teardrop shape, and the upper surface 11 of the packaging bag 10, excluding the seal portions 14 at both ends, has an upwardly convex curved shape.

[0012] As shown in FIG. 1, a packaging bag thickness measuring device 26 according to this embodiment (hereinafter simply referred to as thickness measuring device 26) is disposed downstream of a discharge conveyor 24 in the conveying direction. As shown in FIGS. 1 and 2, the thickness measuring device 26 includes a leveling conveying path 28A, a thickness measuring conveying path 30A, a thickness detecting section 32, and a control device .

[0013] The smoothing conveying path 28A is formed by the upper surface of the upper conveyor belt 2806 of the smoothing conveyor 28, the upstream end of which is connected to the downstream end of the discharge conveyor 24. The leveling conveyor 28, like the discharge conveyor 24, extends at a gentle incline such that its height increases toward the downstream in the conveying direction. The leveling conveyor 28 is composed of a drive roller 2802 that is rotated by a motor not shown, a driven roller 2804, and an upper conveyor belt 2806 that is stretched around the rollers 2802, 2804 and transports the packaging bags 10 on its upper surface, and the transport speed of the leveling conveyor 28 is controlled to a predetermined speed. Furthermore, the leveling conveyor 28 is provided with a vibration section 36 . The vibration unit 36 ​​vibrates the upper conveyor belt 2806 to impart vibrations to the multiple food items 16 that are randomly stacked vertically and horizontally in the packaging bag 10, thereby leveling out the uneven distribution of the multiple food items 16 that are randomly stacked vertically and horizontally in the packaging bag 10, thereby leveling out the teardrop-shaped shape of the packaging bag 10 and making the top surface 11 of the packaging bag 10 almost flat. In this embodiment, the vibration section 36 is composed of a pair of rectangular columnar vibration rollers 3602, 3604 rotatably mounted on the underside of the upper conveyor belt 2806 at a distance from each other in the conveying direction of the conveyor belt 2806, and a motor (not shown) provided for each of the vibration rollers 3602, 3604 for rotating the rollers 3602, 3604. A pair of vibrating rollers 3602, 3604 have four corners and four flat surfaces connecting adjacent corners, and when each is rotated by the motor, the corners and flat surfaces alternately come into contact with the underside of the upper conveyor belt 2806, imparting vibration to the upper conveyor belt 2806. In this embodiment, a pair of vibrating rollers 3602, 3604 and the motor are used as vibrating unit 36, but the configuration of vibrating unit 36 ​​is not limited as long as it can impart vibrations to a plurality of foods 16 randomly stacked vertically and horizontally in packaging bag 10. For example, a commercially available vibration generator may be used to vibrate upper conveyor belt 2806, but the present embodiment is advantageous in simplifying vibrating unit 36, reducing costs, and saving power.

[0014] An upper holding down conveyor 38 is provided above the leveling conveyor 28 so as to face the leveling conveyor 28 at a distance. The upper pressure conveyor 38 is composed of a drive roller 3802 rotated by a motor not shown, a driven roller 3804, and a conveyor belt 3806 that is looped around the rollers 3802, 3804, and the upper pressure conveyor 38 is controlled so as to have the same conveying speed as the leveling conveyor 28. When there is no packaging bag 10 on the upper conveyor belt 2806 of the leveling conveyor 28, the lower portion of the conveyor belt 3806 of the upper holding conveyor 38 that faces the upper conveyor belt 2806 of the leveling conveyor 28 is in a state of hanging downward due to its own weight. Here, when the packaging bag 10 is transported by the upper conveyor belt 2806 of the leveling conveyor 28, the packaging bag 10 is sandwiched between the lower part of the hanging conveyor belt 3806 of the upper holding conveyor 38 and the upper conveyor belt 2806 of the leveling conveyor 28. The packaging bag 10 is conveyed while being sandwiched between the conveyor belts 3806, 2806 from above and below, and is vibrated by the vibrating section . Therefore, even if vibration is applied from the vibrating section 36, the packaging bag 10 is sandwiched between the conveyor belts 3806, 2806, and is therefore prevented from falling off the upper conveyor belt 2806 of the leveling conveyor 28. At this time, since the lower portion of the conveyor belt 2806 of the leveling conveyor 28 is in a downward slack state due to its own weight, the pressing force applied from the conveyor belt 2806 to the upper surface 11 of the packaging bag 10 is the minimum necessary to prevent the packaging bag 10 from falling off the conveyor belt 2806 of the leveling conveyor 28.

[0015] The thickness measurement transport path 30A is formed by the upper surface of the conveyor belt 3006 of the first transport conveyor 30, the upstream end of which is connected to the downstream end of the leveling conveyor . In this embodiment, the first transport conveyor 30 extends in a substantially horizontal direction. The first conveyor 30 is composed of a drive roller 3002 that is rotated by a motor not shown, a driven roller 3004, and a conveyor belt 3006 that is stretched around the rollers 3002, 3004 and conveys the packaging bags 10 on its upper surface, and the conveying speed of the first conveyor 30 is controlled to a predetermined speed. Further, a second transfer conveyor 40 is provided at the downstream end of the first transfer conveyor 30, the upstream end of which is connected to the downstream end of the first transfer conveyor 30. In this embodiment, the second transfer conveyor 40 extends in a substantially horizontal direction. The second conveyor 40 is composed of a drive roller (not shown) that is rotated by a motor (not shown), a driven roller 4004, and a conveyor belt 4006 that is stretched across these rollers and conveys the packaging bags 10 on its upper surface, and the conveying speed of the second conveyor 40 is controlled to a predetermined speed. An injection nozzle 42 is arranged on the side of the second conveyor 40 to inject compressed air into packaging bags 10 whose thickness is determined to be defective by the thickness measuring device 26, thereby removing them from the second conveyor 40. In this embodiment, the first transport conveyor 30 and the second transport conveyor 40 extend in an approximately horizontal direction, but it is optional for one or both of the conveyors 30, 40 to extend at a gentle slope that increases in height toward the downstream in the transport direction, similar to the leveling conveyor 28. In other words, it goes without saying that the inclination and the angle of inclination of the first transport conveyor 30 and the second transport conveyor 40 are appropriately set depending on the layout of the equipment including the conveyors provided before and after the thickness measuring device 26.

[0016] As shown in FIG. 3, the thickness detection unit 32 is disposed above the thickness measurement conveying path 30A, and irradiates detection light L1 onto the upper surface 11 of the packaging bag 10 being conveyed on the thickness measurement conveying path 30A, and generates a thickness detection signal corresponding to the thickness of the packaging bag 10 based on reflected light L2 reflected by the upper surface 11 of the packaging bag 10, and supplies the signal to a control device 34 described later. As such thickness detection unit 32, various types of conventionally known displacement sensors can be used, such as a PSD (one-dimensional position sensitive device) as a light receiving element, or an optical displacement sensor of a triangulation type using a CCD or CMOS. In this embodiment, the thickness detection unit 32 generates a thickness detection signal based on the distance from the position of the upper surface of the conveyor belt 3006 constituting the thickness measurement transport path 30A to the position of the upper surface 11 of the packaging bag . In addition, in this embodiment, a case is described in which the thickness detection signal is an analog signal and the voltage is proportional to the thickness of the packaging bag 10, but the thickness detection signal need only be capable of identifying the thickness corresponding to the thickness of the packaging bag 10, and the thickness detection signal is not limited to an analog signal and may be a digital signal, and the type of thickness detection signal is not limited. FIG. 4(A) shows the change over time of the thickness detection signal, with the horizontal axis representing time t (sec) and the vertical axis representing the voltage S (V) of the thickness detection signal. In this embodiment, since the thickness detection unit 32 is constantly operating, during the period when the packaging bag 10 is not present on the optical axis of the detection light L1, the thickness detection signal becomes a reference value (e.g., 0 V) ​​corresponding to the position of the upper surface of the conveyor belt 3006, and during the period when the packaging bag 10 passes on the optical axis of the detection light L1, the thickness detection signal becomes a voltage S (V) whose magnitude is proportional to (corresponding to) the position of the upper surface 11 of the packaging bag 10.

[0017] As shown in FIG. 2, the control device 34 is configured by a computer, and the computer executes a control program to realize a sampling unit 34A, a thickness calculation unit 34B, a judgment unit 34C, a memory unit 34D, and a statistical data calculation unit 34E.

[0018] The sampling section 34A obtains a plurality of sampling data for each packaging bag 10 by sampling the thickness detection signal supplied from the thickness detection section 32 at a predetermined sampling period. FIG. 4B shows the change in the sampling data over time, with the horizontal axis representing time t (sec) and the vertical axis representing the sampling data D.

[0019] The thickness calculation section 34B calculates a measured thickness value of each packaging bag 10 based on the multiple pieces of sampling data obtained by the sampling section 34A. The thickness calculation unit 34B may calculate the thickness measurement value in the following manner.

[0020] (1) The thickness calculation unit 34B calculates the thickness measurement value by identifying the maximum value among the multiple pieces of sampling data obtained for each packaging bag 10. Explaining this with reference to FIG. 4(B), if the maximum value of the sampling data is taken as Dmax, then this maximum value Dmax of the sampling data is calculated as the measured thickness value of the packaging bag 10. Here, since the positions of the seal portions 14 at both ends of the packaging bag 10 are lower than the position of the upper surface 11 of the packaging bag 10 excluding the seal portions 14 at both ends, it goes without saying that the maximum value Dmax of the sampling data corresponds to the position of the upper surface 11 of the packaging bag 10 excluding the seal portions 14 at both ends of the packaging bag 10, in other words, the position of the upper surface 11 of the bag body 12.

[0021] (2) The thickness calculation unit 34B calculates the arithmetic mean value of the top N (N is a natural number of 2 or more) pieces of sampling data obtained for each packaging bag 10, thereby calculating the thickness measurement value. Here, the top N sampling data only includes sampling data at the positions of the top surface 11 of the packaging bag 10 excluding the seal portions 14 at both ends, and it is necessary to set the upper limit of the value of N so that sampling data at the positions of the seal portions 14 at both ends of the packaging bag 10 is not included. To explain this with reference to FIG. 4B, for example, when N=5, the thickness measurement value is calculated by calculating the arithmetic mean value of the top five sampling data D1-D5.

[0022] (3) The thickness calculation unit 34B calculates a thickness measurement value by calculating a weighted average value weighted by the length along the conveying direction of the packaging bag 10 from the top N (N is a natural number greater than or equal to 2) sampling data of the multiple sampling data obtained for each packaging bag 10. Here, the value of N is set taking into consideration the upper limit, as in the case of (2) above. As explained with reference to FIG. 4(B), for example, when N=5, the thickness measurement value is calculated by calculating a weighted average value weighted by the length along the conveying direction of the packaging bag 10 from the top five sampling data D1-D5. In the cases of (2) and (3) above, the value of N is appropriately set taking into consideration the upper limit mentioned above as well as the sampling period, the accuracy of the thickness measurement value to be obtained, the conveying speed of the first conveyor 30, and the length of the packaging bag 10 excluding the sealed portion 14 (the length of the bag body 12), etc.

[0023] The judgment unit 34C judges whether the measured thickness value of the packaging bag 10 calculated by the thickness calculation unit 34B is within an acceptable range defined by predetermined upper and lower limits, and judges the packaging bag 10 to be a good product if the thickness of the packaging bag 10 is within the acceptable range, and judges the packaging bag 10 to be a defective product if the thickness of the packaging bag 10 is not within the acceptable range. If the judgment unit 34C judges the packaging bag 10 to be defective, it sends an operation signal to the spray nozzle 42, causing compressed air to be sprayed from the spray nozzle 42, and removes the packaging bag 10 judged to be defective from the second transport conveyor 40.

[0024] The memory unit 34D sequentially stores the thickness measurement values ​​of multiple packaging bags 10 calculated by the thickness calculation unit 34B over time, and, for example, stores the thickness measurement values ​​in association with time data (date and time) supplied from a timing unit not shown.

[0025] The statistical data calculation unit 34E calculates statistical data as follows based on the thickness measurements of the plurality of packaging bags 10 calculated by the thickness calculation unit 34B. The statistical data calculation unit 34E may calculate the statistical data based on the thickness measurement values ​​of multiple packaging bags 10 read from the memory unit 34D, or may calculate the statistical data based on the thickness measurement values ​​of multiple packaging bags 10 calculated by the thickness calculation unit 34B. The statistical data may be the difference between the maximum and minimum thickness measurements of the multiple packaging bags 10, the arithmetic average value of the thickness measurements of the multiple packaging bags 10, or the standard deviation value of the thickness measurements of the multiple packaging bags 10.

[0026] Furthermore, the statistical data may be a trend graph showing the change tendency over time of at least one of the above-mentioned difference value, arithmetic mean value, and standard deviation value. The calculated statistical data may be, for example, displayed on the screen of a monitor device (not shown), or may be printed out by a printer device (not shown), or may be transferred to another terminal device or storage medium for use.

[0027] Next, the operation of the thickness measuring device 26 will be described. As shown in FIG. 1, a vertical form-fill-seal packaging machine 20 produces packaging bags 10 containing food products 16 that are randomly stacked vertically and horizontally. The packaging bag 10 is discharged from the vertical bag making, filling and packaging machine 20 toward the discharge chute 22 with its length direction facing vertically, and is transferred from the discharge chute 22 onto the discharge conveyor 24. At this time, the multiple food items 16 contained in the packaging bag 10 and stacked randomly vertically and horizontally are biased toward the sealed portion 14 located downstream of the packaging bag 10 due to their own weight, so that the packaging bag 10 assumes a teardrop shape on the discharge conveyor 24.

[0028] As the packaging bag 10 is transferred from the discharge conveyor 24 to the leveling conveyor 28 and transported, the vibration section 36 vibrates the multiple food items 16, which are randomly stacked and contained in the packaging bag 10, thereby leveling out the uneven distribution of the multiple food items 16 contained in the packaging bag 10, thereby leveling out the teardrop-shaped shape of the packaging bag 10 and smoothing out the upper surface 11 of the packaging bag 10 so that it is approximately flat. The packaging bag 10, whose upper surface 11 has been smoothed to be substantially flat, is transferred from the smoothing conveyor 28 onto the first transport conveyor 30 (thickness measurement transport path 30A) and transported by the first transport conveyor 30 in the transport direction. As shown in Figure 3, when the top surface 11 of the packaging bag 10 passes along the optical axis of the detection light L1 of the thickness detection device, a thickness detection signal corresponding to the position of the top surface 11 of the packaging bag 10 is generated from the thickness detection device and supplied to the sampling unit 34A. The sampling unit 34A generates a plurality of sampling data for each packaging bag 10 by sampling the thickness detection signal at a predetermined period. The thickness calculation unit 34B calculates a measured thickness value for each packaging bag 10 based on a plurality of pieces of sampling data.

[0029] The determination unit 34C determines whether or not the measured thickness value of the packaging bag 10 calculated by the thickness calculation unit 34B is within an acceptable range defined by predetermined upper and lower limits. Eventually, the packaging bag 10 is transferred from the first transfer conveyor 30 to the second transfer conveyor 40 and is transferred by the second transfer conveyor 40 in the transfer direction. Packaging bags 10 that have been determined to be non-defective by determination section 34C are transported by second transport conveyor 40 to a subsequent process, such as packaging of packaging bags 10 into boxes. The packaging bag 10 judged as a defective product by the judging section 34C is removed from the second transport conveyor 40 by the judging section 34C spraying compressed air from the spray nozzle 42. In addition, the thickness measurement values ​​of the multiple packaging bags 10 calculated by thickness calculation unit 34B are stored in memory unit 34D, and statistical data calculation unit 34E calculates statistical data based on the thickness measurement values ​​of the multiple packaging bags 10 calculated by thickness calculation unit 34B.

[0030] According to this embodiment, when a packaging bag 10 manufactured by a vertical form-fill-seal packaging machine 20 and containing a plurality of food products 16 stacked randomly in the vertical and horizontal directions is transported along a thickness measurement conveying path 30A, the thickness detection unit 32 irradiates detection light L1 onto the top surface 11 of the packaging bag 10 being transported on the thickness measurement conveying path 30A and generates a thickness detection signal corresponding to the thickness of the packaging bag 10 based on the reflected light L2 reflected by the top surface 11 of the packaging bag 10, and the thickness calculation unit 34B calculates a thickness measurement value of the packaging bag 10 for each packaging bag 10 based on multiple sampling data for each packaging bag 10 obtained by the sampling unit 34A. Therefore, the thickness measurement value of the packaging bag 10 can be obtained without applying a pressing force to the top surface 11 of the packaging bag 10, and therefore, as in the conventional method, when a pressing member presses the top surface 11 of the packaging bag 10, a portion of the top surface 11 of the packaging bag 10 is not pinched between the pressing member and the protrusions, corners and edges of the multiple foods 16 that are randomly stacked and contained in the vertical and horizontal directions, and a large pressing force is not applied locally to a portion of the top surface 11 of the packaging bag 10. In particular, even if the volume of the packaging bag 10 is relatively small and there is not much room in the storage space of the packaging bag 10 for multiple foods 16 that are randomly stacked vertically and horizontally and are contained therein, and the movement of the multiple foods 16 is restricted when a pressing force is applied to the top surface 11 of the packaging bag 10 by the pressing member, a portion of the top surface 11 of the packaging bag 10 is pinched between the pressing member and the protrusions, corners or edges of the multiple foods 16, so that a large pressing force is not applied locally to that portion of the top surface 11 of the packaging bag 10. This is advantageous in measuring the thickness of the packaging bag 10 while reliably preventing pinholes from occurring on the top surface 11 of the packaging bag 10 in which multiple food items 16 are randomly stacked vertically and horizontally. Furthermore, when applying a pressing force to the upper surface 11 of the packaging bag 10 using a pressing member as in the conventional method, not only is a moving mechanism required to move the pressing member back and forth in a direction toward and away from the upper surface 11 of the packaging bag 10, but it also requires additional operating time to move the pressing member each time the thickness of each packaging bag 10 is measured, resulting in a significant loss of time when measuring the thickness of a large number of packaging bags 10. In contrast, in the present embodiment, a mechanism for moving the pressing member is not required, which is advantageous in simplifying the configuration of the thickness measuring device 26 and reducing costs. In addition, since no operating time is required to move the pressing member each time the thickness of each packaging bag 10 is detected, this is advantageous in efficiently measuring the thicknesses of a large number of packaging bags 10 in a short period of time.

[0031] In addition, in this embodiment, the vibration unit 36 ​​provided on the leveling conveying path 28A vibrates the multiple food products 16 that are randomly stacked vertically and horizontally and contained in the packaging bag 10, thereby leveling the upper surface 11 of the packaging bag 10 to an approximately flat surface; however, the leveling conveying path 28A and the vibration unit 36 ​​may be omitted. However, in the present embodiment, fluctuations in the thickness detection signal corresponding to the upper surface 11 of the packaging bag 10 generated by the thickness detection unit 32 can be suppressed, which is advantageous in reducing variation and error in the thickness measurement value of the packaging bag 10 calculated by the thickness calculation unit 34B and is advantageous in improving the accuracy of the thickness measurement value.

[0032] In the present embodiment, the thickness calculation unit 34B is adapted to calculate the thickness measurement value by identifying the maximum value among the multiple pieces of sampling data obtained for each packaging bag 10. Therefore, since the thickness measurement value can be calculated by a simple process of identifying the maximum value Dmax from a plurality of sampling data, this is advantageous in quickly calculating the thickness measurement value by the thickness calculation unit 34B, which is advantageous in increasing the conveying speed of the first transport conveyor 30 and in improving the efficiency of measuring the thickness of the packaging bag 10 by the thickness measuring device 26.

[0033] In addition, in this embodiment, the thickness calculation unit 34B calculates the thickness measurement value by calculating the arithmetic mean value of the top N (N is a natural number equal to or greater than 2) of multiple sampling data obtained for each packaging bag 10. Therefore, since the arithmetic average value of the top N pieces of sampling data is calculated, this is advantageous in suppressing the variation in the thickness measurement values ​​compared to the case where the maximum value Dmax is determined from multiple sampling data, and is therefore advantageous in improving the accuracy of the thickness measurement values.

[0034] In addition, in this embodiment, the thickness calculation unit 34B calculates the thickness measurement value by calculating a weighted average value weighted by the length along the conveying direction of the packaging bag 10 from the top N (N is a natural number equal to or greater than 2) sampling data of the multiple sampling data obtained for each packaging bag 10. Therefore, since the weighted average value of the top N pieces of multiple sampling data is calculated, this is more advantageous in ensuring the accuracy of the thickness measurement values ​​than when the arithmetic average value of the top N pieces of multiple sampling data is calculated.

[0035] In addition, in this embodiment, the statistical data calculation unit 34E calculates statistical data such as the difference between the maximum and minimum thickness measurements, the arithmetic mean value of the thickness measurements of the multiple packaging bags 10, and the standard deviation of the thickness measurements of the multiple packaging bags 10 based on the thickness measurements of the multiple packaging bags 10 calculated by the thickness calculation unit 34B. Therefore, by calculating statistical data such as these difference values, arithmetic mean values, and standard deviation values ​​each time a certain number of packaging bags 10 are produced or each time a specified amount of time has passed, it is possible to accurately determine whether the functions and operations of the vertical bag form, fill and pack packaging machine 20 are normal or not based on the size and changes in this statistical data, which is advantageous for accurately performing adjustment and maintenance work on the vertical bag form, fill and pack packaging machine 20 and for improving the yield and quality of the packaging bags 10 produced.

[0036] In addition, in this embodiment, the statistical data calculation unit 34E calculates statistical data consisting of a trend graph showing the change tendency over time of at least one of the above-mentioned difference value, arithmetic mean value, and standard deviation value based on the thickness measurement values ​​of multiple packaging bags 10 calculated by the thickness calculation unit 34B. Therefore, by monitoring changes in such trend graphs, it is possible to determine in real time and at an early stage whether the operation and function of the vertical bag form, fill and pack packaging machine 20 is normal, which is advantageous in accurately performing adjustment and maintenance work on the vertical bag form, fill and pack packaging machine 20 and in improving the yield and quality of the packaging bags 10 produced.

[0037] In the present embodiment, the case where the packaging bag 10 is a single packet 10A has been described, but the present invention is of course also applicable to the case where the packaging bag 10 is a continuous packet. A chain bag is made up of a number of bags containing a number of food items stacked randomly vertically and horizontally and connected together via a seal. Like the single packet 10A, the chain packet is also formed of an opaque packaging film, for example, an aluminum-deposited film with light-shielding properties. The chain bag has a length in the direction in which the multiple bag bodies are connected, the bag bodies and the seal portion have a length along the length of the chain bag, and the seal portion is located at both ends of the bag bodies in the length direction. A perforation that enables the bag body to be torn is provided in the middle of the length of the sealed portion, and the perforation extends in a direction perpendicular to the length of the sealed portion. In the case of such a chain bag, it is sufficient to obtain a thickness measurement value for each of the plurality of bags constituting the chain bag, and it goes without saying that the same effects as those of the embodiment can be achieved. [Explanation of symbols]

[0038] 10 packaging bags 10A Single Packet 11 Top side 12 Bag body 14 Seal part 16 Food 20 Vertical form fill packaging machine 20A Horizontal seal part 22 Discharge Chute 24 Discharge Conveyor 2402 Drive roller 2404 Driven roller 2406 Conveyor belt 26 Packaging bag thickness measuring device 28 Leveling conveyor 28A Leveling conveyor path 2802 Drive roller 2804 Driven roller 2806 Conveyor belt 30 First conveyor 30A Thickness detection transport path 3002 Drive roller 3004 Driven roller 3006 Conveyor belt 32 Thickness detector L1 Detection light L2 reflected light 34 Control device 34A Sampling section 34B Thickness calculation section 34C Judgment part 34D storage section 34E Statistical Data Calculation Section 36 Vibration section 3602 Vibration roller 3604 Vibration roller 38 Upper support conveyor 3802 Drive roller 3804 Driven roller 3806 Conveyor belt 40 Second conveyor 4002 Drive roller 4004 Driven roller 4006 Conveyor belt 42 Injection nozzle

Claims

1. A device for measuring the thickness of a packaging bag in which a plurality of food products produced by a vertical form-fill-seal packaging machine are randomly stacked vertically and horizontally, A thickness measurement conveying path extending in a substantially horizontal direction and conveying the packaging bag; a thickness detection unit that irradiates a detection light onto an upper surface of the packaging bag conveyed on the thickness measurement conveying path and generates a thickness detection signal corresponding to the thickness of the packaging bag based on the light reflected by the upper surface of the packaging bag; a sampling unit that obtains a plurality of sampling data for each of the packaging bags by sampling the thickness detection signal at a predetermined sampling period; a thickness calculation unit that calculates a thickness measurement value of the packaging bag for each of the packaging bags based on the plurality of sampling data; A packaging bag thickness measuring device comprising:

2. a leveling conveying path is provided that is connected to an upstream end of the thickness measuring conveying path, A vibration unit is provided on the smoothing conveying path to vibrate the plurality of foods stacked and contained in the packaging bag to smooth the upper surface of the packaging bag to a substantially flat surface.

2. The packaging bag thickness measuring device according to claim 1.

3. The calculation of the thickness measurement value by the thickness calculation unit is performed by identifying a maximum value among a plurality of sampling data obtained for each of the packaging bags.

2. The packaging bag thickness measuring device according to claim 1.

4. The thickness measurement value is calculated by the thickness calculation unit by calculating an arithmetic average value of top N (N is a natural number of 2 or more) of the multiple sampling data obtained for each packaging bag.

2. The packaging bag thickness measuring device according to claim 1.

5. The thickness measurement value is calculated by the thickness calculation unit by calculating a weighted average value weighted by the length of the packaging bag along the conveying direction from top N (N is a natural number of 2 or more) sampling data of the plurality of sampling data obtained for each packaging bag.

2. The packaging bag thickness measuring device according to claim 1.

6. A statistical data calculation unit is further provided that calculates statistical data based on the thickness measurement values ​​of the plurality of packaging bags, The statistical data includes at least one of a difference value between a maximum value and a minimum value of the thickness measurement values, an arithmetic mean value of the thickness measurement values, a standard deviation value of the thickness measurement values, and a trend graph showing a change tendency over time of at least one of the difference value, the arithmetic mean value, and the standard deviation value.

2. The packaging bag thickness measuring device according to claim 1.

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