JP4551856B2 - Shrink packaging defect detection device - Google Patents

Description

  The present invention relates to a defective shrink wrapping that can detect defects that may occur when food, non-food products, or containers that contain them (hereinafter referred to as “packages”) are packaged with a heat-shrinkable film. The present invention relates to a detection device.

  As a shrink wrapping technique, for example, it is known to wrap a package using a heat-shrinkable film made of a heat-shrinkable polypropylene resin or the like. As shown in the order of FIGS. 6A to 6C, the package P is conveyed in the direction indicated by the arrow T, and the band-shaped heat-shrinkable film F0 is supplied so as to follow the package P. To do. When the edges on both sides of the heat-shrinkable film F0 are fused and joined together under the package P, the heat-shrinkable film F becomes cylindrical. The code | symbol f0 points out the junction part which joined the edges of the to-be-packaged goods P together.

  Subsequently, one end f1 of the tubular heat-shrinkable film F1 is fused, and when f2 is cut at the same time while f2 is cut in the middle of the heat-shrinkable film F1, the heat-shrinkable film F1 has a bag shape containing the package P. It becomes. When the package P is heated together with such a bag-shaped heat-shrinkable film F by, for example, placing it on a belt conveyor and carrying it into a heat tunnel, the heat-shrinkable film F shrinks and adheres to the package P. Will do. The heat-shrinkable film F is formed with a plurality of air holes not shown in the figure so that air remaining in the heat-shrinkable film F can escape to the atmosphere during the shrinkage process.

Patent Documents 1 and 2 below disclose techniques for detecting the presence or absence of an object to be packaged in a heat tunnel using a discharge tube. Patent Document 3 below discloses a technique for inspecting whether or not a transparent film can be normally attached to a transparent container. This is because two polarizing plates facing each other are further arranged between the light source and the two-dimensional color image sensor facing each other, and a transparent container with a transparent film is transmitted between the two polarizing plates. Sometimes, a two-dimensional color image sensor monitors an interference color in which white light emitted from a light source is colored by a transparent film.
JP-A-5-262329 JP-A-6-278723 Japanese Patent Laid-Open No. 9-072861

  In the shrink wrapping process as described above, when the fusing of the joints f0, f1 or f2 of the heat shrinkable film F is incomplete, or the heat shrinkable film F is partially broken. Stop failure may occur. When the heat-shrinkable film F with poor sealing is heated, the shrink wrapping becomes incomplete, or the heat-shrinkable film F is wrinkled after heating. And these troubles had to be eliminated one by one by visual inspection.

  Further, the discharge tubes described in Patent Documents 1 and 2 cannot detect a sealing failure of the heat-shrinkable film. In the technique according to Patent Document 3, if the object to be packaged (container) is not transparent, white light is blocked by the object to be packaged, and thus the above-described sealing failure cannot be detected.

  Accordingly, the present invention focuses on the characteristic that when a heat-shrinkable film sealed in a bag shape is heated and shrink-wrapped, the bag body once expands due to the thermal expansion of air, and then contracts. It aims at providing the shrink packaging defect detection apparatus which can detect the sealing defect of an adhesive film reliably.

The present invention relates to a conveying means for sequentially conveying the objects to be packaged enclosed with air in a bag-like heat-shrinkable film having a vent hole, and a process in which the objects to be packaged are conveyed by the conveying means. A shrink wrapping failure detection device for detecting a sealing failure of the heat shrinkable film, provided in a shrink wrapping device provided with a heating means for heating the heat shrinkable film, each of which is transported by the transport means A non-contact type photoelectric sensor for detecting the package to be packaged, and a heat-shrinkable film that expands around the individual packages by thermal expansion of the air by the heating unit. a film detecting means for detecting an expansion degree with a photoelectric sensor of non-contact type detecting, the articles to be packaged detecting means and the film detecting means, the objects to be packaged is the heating hands It characterized in that it is disposed Chigae the height from each other at a predetermined position of the process of passing through.

Furthermore, the present invention is, among the pre-Symbol the packaged product to be packaged is detected by the package item detection unit, said heat-shrinkable film by the film detecting means is inflated to a predetermined degree is detected There is a sorting means for sorting the missing items as defective packaging.

Further , the sorting means identifies one packaged object at a predetermined position from among a plurality of packaged objects arranged in a row based on a detection signal sent from the packaged object detecting means, and the film Sorting is performed based on information from a control device that recognizes a heat-shrinkable film having a sealing failure based on a film detection signal sent from a detection means .

  Furthermore, the film detection means can be displaced in a direction in which the detection area approaches the packaged object or in a direction in which the detection area moves away from the packaged object.

  According to the shrink packaging defect detection device according to the present invention, in the shrink packaging process, the heat-shrinkable film wrapped in a bag shape around the packaged object once swells, and the degree of swelling reaches a predetermined degree. Based on the detection by the film detection means, it can be confirmed that the heat-shrinkable film is normal. Alternatively, if the heat-shrinkable film has poor sealing, the degree of expansion of the heat-shrinkable film will be reduced due to air escaping from that location, or it will not expand at all. Can be confirmed.

  Further, in the shrink packaging defect detection device according to the present invention, the conveying means conveys the objects to be packaged one by one in order, and this is detected and specified by the object to be packaged. In addition, the degree of swelling of the heat-shrinkable film around it can be detected by the film detection means. As a result, it is possible to distinguish between one packaged item conveyed by the conveying unit and the other packaged items, so that the film detecting unit should detect the degree of expansion of the heat-shrinkable film around one packaged item. In addition, it is possible to avoid a situation in which the film detection means detects the degree to which the heat-shrinkable film that encloses another packaged object swells.

  Furthermore, according to the shrink packaging defect detection device, the package detection unit detects and identifies the package, and the film detection unit detects a heat-shrinkable film that swells around the identified package to be detected. Therefore, it can be identified whether the specified packaged item is normal or defective, and the normal product and the defective product can be separated according to the identification data. Therefore, without relying on the visual observation of the operator, after confirming the presence or absence of sealing failure of the heat-shrinkable film by the film detection means as described above, for example, to discard the heat-shrinkable film having the sealing failure It can be reliably recovered.

  Furthermore, in the present invention, a non-contact type sensor in which a detection region capable of detecting a heat-shrinkable film that swells around a package due to thermal expansion of air is applied as film detection means of the shrink wrapping defect detection device. can do. In this case, complicated control by a computer or the like is not required to operate the non-contact type sensor. Moreover, since it is not necessary to make a major modification to the heat tunnel to attach the non-contact sensor to, for example, an existing heat tunnel, there is an advantage that the shrink packaging defect detection device can be installed at low cost.

  Furthermore, the film detection means can be installed so that the detection area can be moved toward or away from the package, and in this case, the following advantages can be obtained. That is, when shrink wrapping is performed using a heat-shrinkable film selected from a plurality of types of heat-shrinkable films having different dimensions, the range (distance) in which the heat-shrinkable film swells around the package The film detecting means can be moved in advance to a position where the heat-shrinkable film can be detected in the vicinity of the limit. Thereby, even if the dimension of a heat-shrinkable film changes, the effect described above can be achieved.

  A shrink packaging defect detection device according to an embodiment of the present invention will be described with reference to the drawings. In the following, detailed descriptions or illustrations of obvious elements such as belt conveyors, heat tunnels, sensors, and control devices are omitted.

  FIGS. 1A and 1B show an example in which the shrink packaging defect detection device 1 according to the present invention is attached to a shrink packaging device 2. The shrink wrapping apparatus 2 includes a transport means 3 for transporting the articles to be packaged P enclosed in the bag-like heat-shrinkable film F together with air in the direction indicated by the arrow T one by one, and the articles to be packaged P being conveyed. And heating means 4 for heating the heat-shrinkable film F in the process.

  The conveying means 3 is a belt conveyor in which an endless belt 31 on which an article to be packaged P is placed is wound around a plurality of rotating wheels 32. In addition, a roller conveyor or the like may be applied as the transport means 3 as long as the article to be packaged P can be transported in the horizontal direction. The heating means 4 has a heat tunnel 41 as a main body, and an article P to be packaged conveyed by the conveying means 3 passes through the inside of the heating tunnel 41. As a heat source for the heating means 4, in addition to warm air, a heating wire may be provided in the vicinity of the conveying means 3 as long as the heat-shrinkable film F can be heated satisfactorily.

  As shown in FIGS. 2 and 3, the shrink packaging defect detection device 1 includes a package detection unit 5 that individually detects and identifies the packages P to be transported one by one by the transport unit 3, and a package Film detecting means 6 for detecting the heat-shrinkable film F expanding around the object P is provided.

  A non-contact type sensor such as a photoelectric sensor, a proximity sensor, or an ultrasonic sensor can be applied to the packaged object detection means 5 or the film detection means 6, respectively. In the present embodiment, a photoelectric sensor including light emitting elements 51 and 61 that emit light such as laser light and infrared rays and detection units 52 and 62 that detect light emitted from the light emitting elements 51 and 61 is packaged. It applies as the object detection means 5 or the film detection means 6. A reflection type (regression reflection type) is preferably applied to the photoelectric sensor detection method from the viewpoint of improving detection accuracy, but is not particularly limited.

  For example, if the detection method of the photoelectric sensor is a counter-transmission type, windows for transmitting light such as laser light and infrared light are provided on both sides of the heat tunnel 41, respectively. Then, as shown in FIG. 1B, the light emitting element 61 of the film detection means 6 is arranged on one outer side of the heat tunnel 41, and the detection unit 62 is arranged on the other outer side of the heat tunnel 41. Similarly to these, the light emitting element 51 and the detection unit 52 of the package detection means 5 are also arranged, but the illustration is omitted. The window may be a hole formed in the side portion of the heat tunnel 41, or more preferably a transparent cover attached to the hole. In addition, when a photoelectric sensor is heat-resistant, it can also be arrange | positioned inside the heat tunnel 41, and it cannot be overemphasized that a window does not need to be provided in this case.

  As described above, the configurations of the package detection unit 5 and the film detection unit 6 are substantially the same. However, as shown in FIG. 2, the package detection unit 5 and the film detection unit 6 have a height different from each other. It is wrong. For this reason, when the article to be packaged P reaches the predetermined position indicated by the point x of the heat tunnel 41, the article to be packaged detecting means 5 detects the article to be packaged P and sends a detection signal. Further, when the heat-shrinkable film F enters the detection area 8 indicated by dots, the film detection means 6 detects the heat-shrinkable film F and sends a film detection signal. These signals are transmitted to the control device 9 shown in FIG. The control device 9 will be described later.

  Alternatively, when the photoelectric sensor is of a reflective type, the light emitting element 61 and the detection unit 62 are arranged on one outer side of the heat tunnel 41 so as to be adjacent to each other, and the light irradiated by the light emitting element 61 is detected by the detection unit. A reflector that reflects to 62 is disposed on the other side of the heat tunnel 41. Moreover, you may apply the area sensor which has a wide strip | belt-shaped detection area which can be detected to the extent of packaging defect as said photoelectric sensor. In addition, when the base of the heat-shrinkable film F is transparent, a photoelectric sensor using the polarization effect described as the prior art or a diffuse reflection type photoelectric sensor may be applied.

  Although not shown, the film detecting means 6 may be attached to the heat tunnel 41 so that it can be displaced in the vertical direction. For example, a plurality of screw holes arranged in the vertical direction are formed on both outer portions of the heat tunnel 41, and light is emitted through bolts that are screwed into any of the screw holes selected from these screw holes. The elements 51 and 61 and the detection units 52 and 62 may be fixed to the heat tunnel 41, respectively.

  Next, operation | movement of the shrink packaging defect detection apparatus 1 is demonstrated. As shown in FIG. 2, the transport means 3 transports the articles to be packaged P contained in the bag-like heat-shrinkable film F in a state where they are arranged in a line in the direction indicated by the arrow T. In this process, each time the articles to be packaged P arranged in a row pass through a predetermined position of the heat tunnel 41 one by one in order, the article to be packaged P detecting means 5 detects the detection signal. Since it sends out, based on this detection signal, the control apparatus 9 can pinpoint one to-be-packaged object P in a predetermined position from the some to-be-packaged objects P arranged in 1 row.

  In addition, when the heat-shrinkable film F that individually encloses the article to be packaged P is heated by the heating means 4, the air inside the article to be packaged P is also individually heated and expanded. At the same time, the air inside the heat-shrinkable film F tries to be released to the outside (atmosphere) from the vent hole of the heat-shrinkable film F, but the vent hole is a pinhole having a diameter of about 1 mm. The flow rate of air that can pass is limited. For this reason, since the air pressure temporarily rises inside the heat-shrinkable film F, the bag-like heat-shrinkable film F swells around the package P.

  The predetermined position indicated by the point x in FIG. 2 is the time when the degree of swelling of the bag-like heat-shrinkable film F is maximized after the heat-shrinkable film F enters the heat tunnel 41 together with the package P. And the time (distance) of the heat-shrinkable film F that swells around the article to be packaged P is set in anticipation of reaching the limit. Thus, since the degree to which the heat-shrinkable film F swells to the maximum is determined to some extent by its original size or shape if the heat-shrinkable film F has no sealing failure, the film detecting means 6 has a heat-shrinkable property. The film F is positioned with respect to the heat tunnel 41 so that the detection region 8 matches the limit of the range in which the film F swells from the package P. The range that swells from the package P includes the top and bottom, the horizontal direction, and the depth direction of the drawing.

  Accordingly, when the control device 9 detects one packaged object P that has reached a predetermined position in the heat tunnel 41, the film detecting means 6 detects the heat-shrinkable film F that swells around the packaged object P. When the film detection signal is transmitted, based on the film detection signal, the control device 9 can recognize that the heat-shrinkable film F has no sealing failure and the heat-shrinkable film F is normal.

  Furthermore, if the film detection means 6 can be displaced in the vertical direction as described above, the detection area 8 of the film detection means 6 can be brought close to or separated from the packaged object P as desired. can get. That is, when shrink wrapping is performed using a heat-shrinkable film F selected from a plurality of types of heat-shrinkable films F having different dimensions, the heat-shrinkable film F swells around the packaged object P. The film detecting means 6 can be moved in advance to an appropriate position where the heat-shrinkable film F can be detected near the limit of the range. Therefore, even if the dimensions of the heat-shrinkable film F are changed, if the heat-shrinkable film F is normal, the film detecting means 6 can appropriately detect the heat-shrinkable film F.

  Alternatively, if the heat-shrinkable film F has a sealing failure, or if there is a tear or the like, air leaks from these locations, so even if the air inside the heat-shrinkable film F is heated by the heat tunnel 41, As shown in FIG. 4, the degree to which the heat-shrinkable film F swells becomes small, or the heat-shrinkable film F does not swell at all. For this reason, when the control device 9 specifies one package P by sending a detection signal from the package detection means 5, the heat-shrinkable film F containing the package P is detected by the film. It does not reach the detection area 8 of the means 6. Accordingly, the film detection signal is not sent from the film detection means 6, and based on this, the control device 9 can recognize that the heat-shrinkable film F has a sealing failure in the package P.

  As described above, according to the shrink packaging defect detection device 1, in the process in which the transport unit 3 transports the package P, the presence or absence of the heat-shrinkable film F that swells around the package P is detected as a film detection unit. 6 can be individually determined, and one packaged article P conveyed to the conveying means 3 can be distinguished from the other packaged articles P. Therefore, when the film detection means 6 detects the heat-shrinkable film F that swells around one packaged object P, the film-detecting means 6 incorrectly detects the heat-shrinkable film F that contains another packaged object P. Will not be detected.

  Further, the heat-shrinkable film F having a sealing failure and the normal heat-shrinkable film F are recognized and recognized by the control device 9, and are classified by the sorting means 7 shown in FIGS. The separating means 7 is provided outside the vicinity of the exit of the heat tunnel 41, a nozzle 71 installed in the vicinity of the conveyor, an air compressor 72 that supplies compressed air to the nozzle 71, and between the nozzle 71 and the air compressor 72. And a solenoid on-off valve 73 that opens and closes in accordance with a command from the control device 9.

  Since the solenoid opening / closing valve 73 is closed while the article P to be packaged contained in the normal heat-shrinkable film F is transported by the transport means 3 and passes through the vicinity of the nozzle 71, the normal heat-shrinkability is maintained. The article P to be packaged together with the film F is continuously conveyed by the conveying means 3. And if the to-be-packaged object P included in the heat-shrinkable film F having a sealing failure tries to pass through the vicinity of the nozzle 71, the control device 9 opens the solenoid opening / closing valve 73, so that it is injected from the nozzle 71. The package P is blown off together with the heat-shrinkable film F having a sealing failure by the compressed air, and falls from the conveying means 3. Then, you may collect | recover the to-be-packaged goods P with a chute | shoot etc. with the heat-shrinkable film F with a sealing defect.

  The timing at which the compressed air is injected from the nozzle 71 is set as follows. For example, if the speed at which the transport means 3 transports the package P is constant, the time until the package P passes through the vicinity of the nozzle 71 from a predetermined position of the heat tunnel 41 is known. When the heat-shrinkable film F is confirmed to have a sealing failure as described above, the timer circuit is started, and the time required for the article to be packaged P to pass through the vicinity of the nozzle 71 from a predetermined position has elapsed. The solenoid on-off valve 73 may be opened. Alternatively, if the rotary encoder 74 connected to the control device 9 detects the angle at which the rotating wheel 32 of the transport means 3 rotates, the control device 9 can transfer the packaged material transported to the transport means 3 based on this angle. Since the distance of P can be calculated, the control device 9 may open the solenoid opening / closing valve 73 when the article to be packaged P passes the vicinity of the nozzle 71.

  It should be noted that the present invention can be implemented in variously modified, modified, or modified forms based on the knowledge of those skilled in the art without departing from the spirit of the present invention. For example, the package detection unit 5 shown in FIG. 2 is located directly above the film detection unit 6, but the package detection unit 5 may be shifted to the left and right in the drawing. Further, as the sorting means 7, an arm or a damper that retracts the article to be packaged P from the conveyor by contacting the article to be packaged P in a timely manner may be applied.

  Furthermore, as shown in FIG. 5, the film detection means 6 may be a distance measuring sensor that can measure the distance to the heat-shrinkable film F by reflecting infrared rays or ultrasonic waves on the heat-shrinkable film F. . In this case, the distance measuring sensor 63 is disposed near the top surface of the heat tunnel 41, and the degree of expansion of the heat shrinkable film F is detected based on the distance h from the distance measuring sensor 63 to the heat shrinkable film F. That is, the presence / absence of a sealing failure can be determined based on whether the distance h is larger or smaller than an intended value (degree). Further, the package detection means 5 or the sorting means 7 can be omitted, and when the control device 9 confirms a sealing failure, the operator can be notified by sounding a buzzer or the like. Further, the arrangement of the package detection means 5 may be forward or backward in the direction in which the conveyance means 3 conveys the package P.

  The shrink packaging defect detection device according to the present invention is not affected by the color, light transmittance, or reflectance of the heat shrink film, and reliably seals the heat shrink film that contains all the items to be packaged. Can be detected.

(A) is a front view which shows the outline of an example of the shrink packaging defect detection apparatus which concerns on Example 1 of this invention, (b) is the side surface. The front view which shows notionally an example of operation | movement of the shrink packaging defect detection apparatus which concerns on Example 1 of this invention. The block diagram which shows the principal part of the shrink packaging defect detection apparatus which concerns on Example 1 of this invention. The front view which shows notionally other examples of operation | movement of the shrink packaging defect detection apparatus which concerns on Example 1 of this invention. The front view which shows the outline of the other example of the shrink packaging defect detection apparatus which concerns on Example 1 of this invention. The perspective view which showed the pre-process of shrink packaging in order of (a) thru | or (c).

Explanation of symbols

1: Shrink wrapping detection device 2: Shrink wrapping device 3: Conveying means 4: Heating means 5: Packaged object detecting means 6: Film detecting means 7: Sorting means 8: Detection area F: Heat shrinkable film P: Packaged object

Claims (4)

Conveying means for sequentially conveying the objects to be packaged enclosed with air in a bag-like heat-shrinkable film having a vent hole, and the heat shrinkability in the process of conveying the objects to be packaged by the conveying means A shrink wrapping failure detection device that is provided in a shrink wrapping device comprising a heating means for heating a film and detects a sealing failure of the heat shrinkable film,
Packaged object detection means provided with a non-contact photoelectric sensor for detecting each of the packaged objects conveyed by the conveying means;
A film detecting means comprising a non-contact photoelectric sensor for detecting the degree of expansion of a heat-shrinkable film that expands around the respective packaging objects as the air is thermally expanded by the heating means ;
The shrink packaging defect detection device, wherein the packaged object detection means and the film detection means are arranged at different positions at predetermined positions in the process of passing the packaged object through the heating means. .   Out of the packages to be packaged whose packages have been detected by the packages to be packaged detection means, those that have not been detected by the film detector to have the heat absorbing film expanded to a predetermined degree are regarded as defective packaging. The shrink packaging defect detection device according to claim 1, further comprising a sorting unit for sorting. The sorting unit specifies one packaged object at a predetermined position from a plurality of packaged objects arranged in a line based on a detection signal sent from the packaged object detecting unit, and the film detecting unit The shrink packaging defect detection device according to claim 2 , wherein sorting is performed based on information from a control device that recognizes a heat-shrinkable film having a sealing failure based on a film detection signal sent from the device. The film detecting means is any one of claims 1 to 3, the direction the detecting region approaches the material to be packaged, or the detection region, characterized in that the displaceable in a direction away from the material to be packaged The shrink packaging defect detection device as described in 1.

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