JPH036054B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an unmanned automated process for determining the quality of the sealing condition of heat-sealed packaging products and sorting out packaged products with defective heat-sealed parts. The present invention relates to a product sorting method and device.

In the field of packaging machinery, there has been remarkable progress in technology for continuously packaging food, pharmaceuticals, industrial products, and other objects at high speed. Currently, we rely on so-called visual inspection, which involves carefully checking the packaging condition one by one.

By the way, the packaging condition varies greatly depending on the size and shape of the object to be handled, the material of the packaging material, etc., so a single device can be used to determine the packaging condition. Although it is difficult to do so, if it were possible to automate the process of determining and sorting the packaging condition of heat-seal packaging bags, which are typical among packaging bags, the industrial applicability would be extremely large. be.

Pillow packaging bags, three-side seal packaging bags, four-side seal packaging bags, etc. are generally known as heat-seal packaging bags, and it is common to use means of hermetic packaging by heat-sealing a synthetic resin film. If the temperature, pressure, etc. during fusion are not uniform or low, sealing failures often occur at those locations. Another type of sealing failure is a sealing failure in which wrinkles, particularly vertical wrinkles, occur in the film during fusion, and the fusion is not performed at that location.

The present inventor conducted a comparative study of areas in the heat-sealed portion where the sealing condition is good and areas where the sealing condition is poor, with the aim of providing a device for determining and sorting the quality of the heat-sealing condition of such heat-sealing packaging bags. As a result, the following findings were obtained.

In other words, air may have entered the area where the heat seal is defective, foreign matter may have entered the area, or the films may have overlapped. If the film has the property of transmitting heat-sealed particles, the amount of transmitted light will naturally differ between areas where the heat seal is good and areas where the heat seal is defective.

From this, we have completed the present invention, in which a light beam is transmitted through the heat-sealed portion of a heat-seal packaging bag, and the quality of the sealing condition is judged and sorted based on the difference in the amount of transmitted light.

Therefore, the gist of the present invention to achieve the object of the present invention is to provide a method invention that includes (a) a step of continuously conveying a packaged product having a heat-sealed portion at the end; Step (c) of capturing an image using a light beam that passes through the heat sealing section when the heat sealing section passes through a predetermined position; (c) A/D conversion is performed on the imaging signal obtained by the imaging, and the image signal is transmitted over the entire surface of the heat sealing section; Step (d) of storing as multi-level gradation data according to the dose: Comparing the stored value stored as the gradation data with a threshold set separately according to conditions,
(e) Storing the memory value as 0/1 data with values below the threshold value as 0 and values above the threshold value as 1. (e) 0/1 data for the entire surface of the heat seal part does not pass the predetermined criteria for determining a defective heat seal part. When more than one step outputs a bad signal
A method for selecting packaged products having a defective heat-sealed portion, the method comprising steps (a) to (e).

As an apparatus invention, there is provided a conveyance means for successively conveying packaged products having a heat-sealed portion at an end thereof, and a light beam provided in a conveyance path of the conveyance means to the heat-sealed portion of the packaged product being conveyed. a light source for projecting a light beam; and a light beam source disposed at a position facing the light source across the conveyance path to image the heat-sealed portion of the packaged product being conveyed with a transmitted light beam when the seal portion crosses the light beam. an image storage means for converting an image signal obtained by the imaging means from analog to digital and storing it as multi-level gradation data corresponding to the transmitted dose for the entire surface of the heat sealing section; The stored value stored as tone data is compared with a threshold set separately according to conditions, and when the stored value is less than or equal to the threshold, it is set as 0, and when it is above, it is set as 1, and the stored image is set as 0. /1 image processing means for converting and storing data;
and a determination means for outputting a defect signal when the 0/1 data for the entire surface of the heat seal part does not pass a predetermined criterion for determining a defective heat seal part. The packaging product sorting equipment has a

The present invention will be described below based on embodiments shown in the drawings.

FIG. 1 shows a schematic front view of a device for mechanically operating the device of the present invention, and a packaging machine (not shown) is disposed on the right side of the figure.

In the figure, 1 is a roller conveyor type conveyor that conveys the packaging bags 2 from the packaging machine to the stacking section on the left side of the figure at a constant speed, and this conveyor 1 stops individual packaging bags on any conveyance surface. Alternatively, a slip torque conveyor (trade name: manufactured by Daiko Shuttleworth Co., Ltd.) is used, which has the feature of being able to freely convey other packaging bags even when the speed is reduced. In addition, an opening 1a is provided in the middle of the conveyor path of the conveyor 1.
An imaging device 3 is provided above the opening 1a, and a light source 4 is provided below.
is provided, and the light beam from this light source 4 passes through the aperture 1a.
The heat sealing part of the packaging bag 2 containing the currency is irradiated,
The light beam transmitted through the heat-sealed portion is imaged by an imaging device 3 (hereinafter, this imaging position will be referred to as a detection portion).

In this example, the heat-sealed portion of the packaging bag 2 is made of a transparent film, so the light source 4 is a white lamp that emits visible light, and the imaging device 3 is a television camera. ing. In order to irradiate the heat-sealed portion with the light from the light source 4 with a uniform luminous flux and luminous intensity, a ground glass 5 is attached to the opening 1a in this row. Note that in addition to visible light, infrared rays, X-rays, etc. may be used as the light source, and in that case, an imaging device for capturing an image of transmitted rays may be appropriately selected depending on the light rays. Therefore, in the present invention, the term "light rays" includes not only visible rays but also infrared rays, X-rays, and the like.

Incidentally, in order to capture a still image of the heat-sealed portion of the packaging bag 2 during transportation, the imaging device (television camera) 3 is equipped with an electronic shutter 6 that can be shuttered at high speed. is connected to an electronic shutter control device, which will be described later, so that the shutter can be turned off in a timely manner.

Furthermore, in this embodiment, in order to improve the resolution of the still image, when the front heat sealing part 2a on the front side in the conveyance direction and the post heat sealing part 2b on the rear side in the conveyance direction of the packaging bag 2 pass the detection part, A first braking roller device 7 provided on the upstream side of the conveyance path with the detection section as the center.
and a second brake roller device 8 provided on the downstream side of the conveyance path, the speed at which the packaging bag 2 passes through the detection section is made slower than the conveyance speed of the conveyor 1. 1st
The first brake roller device 7 and the second brake roller device 8 have the same structure, and only differ in their mounting orientation as shown in the figure, so the first brake roller device 7 will be explained.

As shown in the figure, the first brake roller device 7 has a cylindrical damping roller 7b rotatably attached between the rotating tips of a pair of rotating arms 7a facing each other along the conveyance direction. Starting point 7c
It has a structure in which a solenoid-plunger 7d is connected to the rear rotating rear end of the rotating arm 7a.
The rotating tip is pushed upward in the figure to convey the packaging bag 2 at the conveyance speed of the conveyor 1, and when the preheat sealing part 2a of the packaging bag 2 approaches the detection part, the power to the solenoid plunger 7d is cut off. Then, the rotating tip of the rotating arm 7a is pushed down in the figure by a spring (not shown), and the packaging bag 2 is pressed against the conveyance surface by the sponge roller 7b. By the way, this sponge roller 7b is rotated clockwise (in the conveying direction) by a motor (not shown) at a speed slower than the conveying speed of the conveyor 1, so the packaging bag 2 is detected by the rotational speed of this sponge roller 7b. It will pass through the section. The second brake roller device 8 is used to make the speed of the packaging bag 2 passing through the detection section slower than the conveyance speed of the conveyor 1 when the post-heat sealing section 2b of the packaging bag 2 approaches the detection section.

Reference numeral 9 denotes a discharge lever that is operated based on a defect signal provided on the downstream side of the conveyance path of the detection section, and the packaging bag whose heat sealing part is determined to be defective is discharged from the chute 10.
It's starting to push out.

Reference numeral 11 denotes a first detector that detects when the preheat sealing part 2a of the packaging bag 2 approaches the detection part, and is composed of a light-emitting element and a light-receiving element, which are provided facing each other on both sides of the conveyor 1. When the light from the light emitting element is blocked by the packaging bag 2, an activation signal is sent to the first brake roller unit 7. 12
is a second detector connected to the electronic shutter control device, which is configured similarly to the first detector, and when the front heat seal portion 2a of the packaging bag 2 blocks light from the light emitting element, the electronic shutter is activated. A signal is input to the control device, the electronic shutter 6 is activated, and the television camera 3 images the preheated seal portion 2a.
Reference numeral 13 denotes a third detector that operates the second brake roller device 8, and is configured similarly to the first detector. 14 is the post heat sealing part 2b of the packaging bag 2
A fourth detector is configured in the same manner as the first detector 11 and is connected to the electronic shutter control device so that the image is captured by the detection unit. When 2a blocks light from the light emitting element, a signal is input to the electronic shutter control device. The first and second brake roller devices 7 and 8 are designed to return to their original positions when the electronic shutter is closed. In addition, the first to fourth detectors are arranged as shown in the figure from upstream to downstream of the conveyance path, and their placement positions are determined as appropriate in consideration of the length of the packaging bag 2 and the conveyance speed. It is being

FIG. 2 is a diagram showing the shutter timing of the electronic shutter.

The pre-heat sealed portion 2a of the packaging bag 2 is the first detector 1
1, the first brake roller device 7 is actuated to reduce the speed of the packaging bag 2. Then, when the front heat sealing part 2a of the packaging bag 2 crosses the optical axis of the second detector 12 in the deceleration state, this second detector 1
A signal is input from 2 to the electronic shutter control device,
After waiting for the front heat seal part 2a to move to the inspection section, the electronic shutter 6 is turned off, and the front heat seal part 2a is imaged as a still image by the camera 3. After imaging, the operation of the first brake roller device 7 is released, the packaging bag 2 moves at the conveyance speed of the conveyor 1, and the front heat-sealed part 2a of the packaging bag 2 crosses the optical axis of the third detector 13. Then, the second brake roller device 8 is operated to reduce the conveyance speed of the packaging bag 2. When the front heat-sealed portion 2a of the packaging bag 2 crosses the optical axis of the fourth detector 14, a signal is input from the fourth detector 14 to the electronic shutter control device, and the rear heat-sealed portion 2a of the packaging bag 2 Waiting for the seal 2b to enter the inspection section, the electronic shutter 6 is turned off, and the camera 3 captures a still image of the heat-sealed portion 2b. When the electronic shutter 6 closes, the second brake roller device 8 is deactivated.
The packaging bag 2 is transported to a collection section or the like at the transport speed of the conveyor 1.

FIG. 3 is a schematic diagram showing an example of an apparatus for determining and sorting the quality of the sealing state of the heat-sealed portion of a packaging bag, which is imaged by a television camera.

The light from the light source 4 that passes through the heat-sealed portion of the heat-seal packaging bag 2 is transmitted to the TV camera 3 as a large amount of transmitted light in areas where the sealing condition is good, and as a small amount of transmitted light in areas where the sealing condition is poor. The imaging signal from the television camera 3 is input to the image storage device 16 via the camera control device 15.

The imaging signal input to this image storage device 16 is an analog quantity, which is converted into a digital signal by an A-D converter, and multi-level gradation (shading) is generated over the entire area of the imaged heat sealing part. It is stored as image data of a collection of points.

In the image data stored here, dark colored points are locations where the amount of transmitted light transmitted through the heat seal portion is small, and light colored points are locations where the amount of transmitted light is large. In other words, the darker the color, the closer the heat-sealed state is to poor, and the darker the color, the closer the heat-sealed state is to good.

In the present embodiment, such image data (hereinafter referred to as first image data) is converted into a similar color and displayed on the color monitor 17, so that the threshold value described below can be easily set. ing.

18 is a microcomputer to which first image data from the image storage device 16 is input via a DMA interface, and performs image processing on the first image data according to a predetermined program to be described later, and after the image processing. A determination process is performed on the image data (hereinafter, this image data will be referred to as second image data). In this embodiment, this second image data is displayed together with the first image data on the color monitor 17, and the result of the judgment process is further displayed on the monochrome monitor 20 connected to the image storage device 16. ing.

Note that when the next image signal is input from the television camera 3 to the image storage device 16, the stored image data is automatically deleted.
21 is a keyboard for the microcomputer 1;
8 is connected.

Reference numeral 22 denotes an electronic shutter control device that controls the shutter timing of the electronic shutter 6. In order to store the image data stored in the image storage device 16 from a predetermined position,
When the signal from the detector is input, one signal is input to the image storage device 16, and when the V synchronization signal of the image storage device 16 is synchronized with this signal, the shutter is activated.
An ON signal is sent to the electronic shutter control device 22, and the electronic shutter 6 is turned off. Further, this electronic shutter 6 is connected to the microcomputer 1.
8, so that the heat sealing section of the packaging bag to be imaged can receive instructions from the front heat sealing section and the rear heat sealing section, or from the front heat sealing section and the rear heat sealing section, from the microcomputer. . 2
Reference numeral 3 denotes an interface for transmitting a defective product discharge signal from the microcomputer 18 to the defective product discharge lever 9.

Next, image processing of the first image data will be explained.

This image processing step is a boundary setting processing step (P ₁ ), and the gradation levels of the first image data, which is a collection of points with multiple levels of gradation, were set according to conditions such as the material and thickness of the packaging bag, the strength of the light source, and the position of the camera. It includes two steps, a threshold value processing step (P ₂ ), which converts data into 0/1 data, with points lighter than the level being 0 and points darker than the level being 1, at an arbitrary level. .

Specifically, the first image data has 256 levels of shading, the points in the (0-127) level are 0, the points in the (128-255) level are 1, and this 0/1 data is 224 × 40
It is a collection of individual points.

Next, the criteria for determining a defective heat-sealed portion will be explained.

In this example, when determining the criteria for determining whether a heat-sealed part passes or fails, the conditions in which heat-sealing is considered to be defective are defined as (a) a state in which heat-sealing is insufficient over the entire heat-sealed part; There are three states: (b) a state in which local heat sealing is insufficient, and (c) a state in which heat sealing is insufficient in the longitudinal direction of the heat eel portion.

The criteria for determining a defective heat-sealed portion are, for example, the first, second, and third criteria defined below. In other words, the first criterion is to reject the case where the number of heat seal defective points 1 is equal to or greater than a predetermined value in the entire heat seal area, and the second criterion is to reject the case where the number of heat seal defective points 1 is equal to or greater than a predetermined value in the entire heat seal area. The third criterion is that the product is rejected if the number of the packaging bag is greater than or equal to a predetermined value, and the third criterion is that it is rejected if there is even one vertical seal failure area that communicates between the inside and outside of the packaging bag. This is the criterion.

Note that the above-mentioned criteria are established for typical heat seal failure states, and various other criteria may be determined as necessary.

Furthermore, these criteria will be explained in detail.

First Judgment Criterion The first criterion is that for the 0/1 data processed in step (P ₂ ) as described above,
Compare all the data points with 1 data point, 1
The standard is to judge the quality of heat sealing based on whether the number of data points is greater or less than a predetermined value (DLVL), so this predetermined value (DLVL) is determined empirically, and specifically, DLVL = 500, 224×40
= If there are 500 or more data points of 1 out of 8960 data points, it is determined that there are many scratches or overlapping parts in the entire heat-sealed part. ) signal is output to determine whether the heat seal is good or bad for the entire heat seal section (P ₃ ).

Second judgment criterion The 0/1 data processed in step _P2 is a collection of individual points, but each data point is not completely independent and has a deep relationship with surrounding points. Therefore, a certain spread (m×
Apply a mask with 0/1 data (n pieces) to the 0/1 data, pick up the state of the data within the spread, and find out if 1 data point out of m x n data points is greater than or equal to a predetermined number (AL). If the data area that was masked at that time is set as a new data area 1 (thermal seal failure concentration area), if the number of such heat seal failure concentration areas is greater than a predetermined value (ARR), there will be a local seal failure in the heat seal area. The criteria for determining that
In the case of failure, a local heat seal quality determination step (P ₄ ) is performed in which a failure (ejection) signal is output. Specifically, m=3, n=3, AL=6,
ARR = 500, 1 point among 9 masks is 6
An area with more than 1 area is defined as 1 area, and this 1 area is
If there are 500 or more seals, it is determined that the sealing condition is locally defective, and if the condition fails, a defective signal is also output.

Third criterion: Scan along the width direction by applying a slit of size K (horizontal) x l (vertical) to the 0/1 data processed in step (P ₂ ).
One point within each slit area is a predetermined value (VL)
If the area is larger than the specified value (VLL), the area is defined as 1, and if the area is larger than a predetermined value (VLL), it is determined that there is a longitudinal seal failure area in the heat sealing part that passes inside and outside the packaging bag. In the case of failure, a vertical heat seal quality determination step (P ₅ ) is performed in which a failure (ejection) signal is output. Specifically, K = 5, l = 40, VL = 60, VLL = 0, and 200
If there is even one area with 60 or more points of 1 among the slits, it will be determined that there is a defective vertical seal area that communicates the inside and outside of the packaging bag, and if the bag is rejected, the same applies. outputs a defective signal.

The predetermined values for each criterion explained above were obtained from experience, and satisfactory results were obtained in actual use. Also, the aperture of the TV camera is 4~
I used between 6.5 and 6.5.

FIG. 4 is a flowchart showing an example of the execution order of the apparatus according to this embodiment.

First, a detector detects whether or not there is a packaging bag in the detection section on the conveyor 1, and if so, a television camera images the heat-sealed part of the packaging bag, and the imaging signal is transferred to the image storage device 16. . The image signal is input to the microcomputer 18 as image data (first image data) that has been digitally converted into multiple gradations (shades) by an image storage device. In this first image signal, the image data of only the heat-sealed part is extracted at (P ₁ ), and further, at (P ₂ ), the level of the color darker than the threshold level set in advance is set to 1, The image data is converted into image data (second image data) in which the level of a color darker than the level is set to 0, and is displayed on the monitor.

Next, for this second image data (P ₃ )
The number 1 point is compared with the total number of points, and if the number of 1 points is greater than the set value, it is determined that the seal is defective, and an ejection signal is output to operate the ejection lever. Furthermore, in (P ₄ ), a mask scan is performed on the second image data using a mask of size m×n, and the data area in which the number of 1 points in the mask exceeds the set value is defined as 1. If the data area is larger than the set value, it is determined that there is a local seal failure in the heat seal section, and an ejection signal is output to operate the ejection lever. Finally ( _P5 )
Perform a slit scan on the second image data in the width direction using slits of width (K x l), and if one point within the slit area exceeds the set value,
This area is defined as 1, and if the number of slit areas of 1 is greater than the set value, it is determined that there is a seal failure in the longitudinal direction, and an ejection signal is output to operate the ejection lever.
Then, the above calculation results of (P ₃ ), (P ₄ ), and (P ₅ ) are displayed on the monitor.

As described above, according to this embodiment, it is possible to inspect the sealing state of the front heat sealing part and the post heat sealing part of heat seal packaging bags that are continuously made by a packaging machine without having to stand still. Then,
Moreover, even when the conveyor speed is high, images with very high resolution can be obtained because the conveyance speed is slowed down by the brake roller when the packaging bag passes through the inspection section.

In this embodiment, if the conveyance speed of the conveyor is slow, it is not necessary to operate the brake roller device.

Further, in this embodiment, the first image data, the third image data, and the calculation results are displayed on the monitor, but these data may not be output on the screen and only the ejection lever may be operated. .

As described above, according to the present invention, it is possible to mechanically determine the quality of the sealing condition of heat-sealed packaging bags and to sort them, so the entire packaging process can be automated, and its usability is It is a big thing.

[Brief explanation of the drawing]

Fig. 1 is a schematic front view of a device for performing mechanical operations of the device of the present invention, Fig. 2 is a timing chart showing the shutter timing of the electronic shutter shown in Fig. 1, and Fig. 3 is a judgment of the device of the present invention. FIG. 4 is a schematic diagram showing an embodiment of the apparatus, and FIG. 4 is a flowchart showing the execution order of the control device of FIG. 3. DESCRIPTION OF SYMBOLS 1... Conveyor, 2... Packaging bag, 2a... Front heat sealing part, 2b... Back heat sealing part, 3... Television camera, 4... Light source, 5... Ground glass, 6...
...Electronic shutter, 7...First brake roller device, 7
a...Rotating arm, 7b...Sponge roller, 7
c...Rotation fulcrum, 7d...Solenoid plunger, 8...Second braking roller device, 9...Discharge lever, 10...Discharge chute, 11...First detector, 12...Second Detector, 13... Third detector, 14... Fourth detector, 15... Camera control device, 16... Image storage device, 17... Color monitor, 18... Microcomputer, 19... …
DMA interface, 20...Monitor, 21
...Keyboard, 22...Electronic shutter control device, 23...Interface.

Claims (1)

[Claims] 1. (a) Continuously transporting a packaged product having a heat-sealed portion at the end; (b) When the heat-sealed portion of the product passes a predetermined position during transportation, the heat-sealed portion of the product passes through a predetermined position; (c) A step of performing an A-D conversion on the image signal obtained by the imaging and storing it as multi-level gradation data corresponding to the transmitted dose for the entire surface of the heat-sealed part. (d) Compare the stored value stored as the gradation data with a threshold value separately set according to conditions,
0/ where the memory value is below the threshold value is 0 and above is 1
Step (e) of storing the data as 1 data; Step (e) of outputting a defect signal when the 0/1 data for the entire surface of the heat seal part does not pass the predetermined criteria for determining a defective heat seal part; (a) to (e) above; A method for sorting packaging products having defective heat-sealed parts, the method comprising the steps of: 2. Conveying means for successively conveying packaged products having heat-sealed portions at the ends thereof, and a beam of light projected onto the heat-sealed portions of the packaged products that are disposed in the conveyance path of the conveyance means and are being conveyed. a light source disposed at a position facing the light source across the conveyance path, and for imaging the heat-sealed part of the packaged product being transported with a transmitted light beam when the heat-sealed part crosses the light beam; an imaging means; an image storage means for converting an image signal obtained by the imaging means from analog to digital and storing it as multi-level gradation data corresponding to the transmitted dose for the entire surface of the heat sealing part; and the gradation data. The stored image is compared with a threshold value that is separately set according to conditions, and when the stored value is less than or equal to the threshold value, it is set as 0, and when it is above the threshold value, it is set as 1, and the stored image is set as 0/1. an image processing means for converting and storing data;
and a determination means for outputting a defect signal when the 0/1 data for the entire surface of the heat seal part does not pass a predetermined criterion for determining a defective heat seal part. packaging product sorting equipment.