JPH0853111A - How to detect defective seals in packaging machines - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide a method for detecting whether or not there is a defective seal part in the lateral seal part of a bag in a packaging machine in which an opening is laterally sealed after an object to be encapsulated is introduced. To do. [Structure] The method for detecting a defective seal according to the present invention is based on the projector 2
0 is applied to the horizontal seal part b, and the transmitted light is received by the photodetector 30.
Is a method of detecting a defective seal by receiving light by using two photodetectors A and B arranged side by side in the traveling direction of the bag, and the difference in the amount of light received between the photodetectors A and B is equal to or greater than a set value. A pulse is generated and it is detected by the number of pulses whether there is a defective seal portion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting whether or not there is a defective seal part in a lateral seal part of a bag in a packaging machine in which an opening is laterally sealed after an object to be encapsulated is introduced.

[0002]

2. Description of the Related Art A packaging machine is a feeding station for feeding bags one by one and gripping both vertical seal portions, a filling station for inserting an object to be sealed into an opened bag via a hopper, and a pressing station for pushing the bags. , Bag delivery, delivery, delivery and receiving station, gas filling station for filling gas, sealing station for lateral sealing of bag opening, cooling station and discharge station. Then, we applied for “Defective seal detection device in packaging machine” filed on August 3, 1993 (Japanese Patent Application No. 5-2
12213), in order to detect whether or not there is a defective seal portion (for example, a chamfered piece) in the horizontal seal portion,
It was proposed to add a detection station after the sealing station and discharge good products to the good product station and defective products with chaffed pieces to the defective product station according to the detected state. An outline of the configuration of the detection station will be described. A light emitter and a light receiver are set, and the light emitter projects a lateral seal portion of a bag a which is conveyed between the light receiver and the light receiver, and the light receiver determines the amount of transmitted light. When the measured amount of transmitted light is less than or equal to the set value, it is determined that there is a chamfered piece of the encapsulation in the horizontal seal portion, and the defective product is discharged from the defective discharge station as a defective product.

[0003]

The above-mentioned conventional defect detection method is performed by detecting the amount of change in the static transmission amount of light in the horizontal seal portion. The amounts are subtly different, and it may be difficult to measure and detect such a change to determine whether or not it is a chaff. Therefore, according to the present invention, the light emitted from the projector to the horizontal seal portion is received by the light receiver, and based on the change amount (difference) of the received light amount, is there a chamfered piece of the object to be encapsulated in the horizontal seal portion? It is intended to provide a method of detecting whether or not.

[0004]

The detection method according to claim 1 is
Two photo detectors are arranged side by side in the traveling direction of the bag, a pulse is generated when the difference in the amount of light received by the photo detectors is equal to or greater than the set value, and the number of pulses detects whether there is a defective seal. To do. The second aspect of the invention is to detect the defective seal portion by setting the pulse width generated in the first aspect longer than the time required to pass through the vertical seal portion.

[0005]

In the state of the vertical seal and the horizontal seal, light is received by the pair of light receivers, so that the adjacent parts simultaneously receive light. Therefore, when the difference in the amount of received light is equal to or larger than the set value, a pulse is emitted. Therefore, the pulse is generated at the edge of the bag or a place such as a chamfered piece, and by counting the number of pulses, a normal bag and a bag having a defective seal portion with a chamfered piece are distinguished. Also, claim 2
Causes one pulse to be generated in the vertical seal portion by making the time constant of the generated pulse larger than the time it takes to pass through the vertical seal portion. Therefore, the number of pulses generated is two in the vertical seals at both ends in the case of a normal bag, but when there is a chamfered piece, the number of pulses becomes higher than that of the horizontal seals. Defects can be detected.

[0006]

DETAILED DESCRIPTION FIG. 1 is a plan view of a detection station and FIG. 2 is a side view. The bag a having the vertical seal portions c formed on the bottom portion and both vertical edges has a horizontal seal b in which the opening is overlapped with the vertical seal portion c at both edges after the object to be encapsulated is loaded at a loading station (not shown). It Then, in the detection station shown in FIG. 1 (FIG. 2) in a state where both vertical seal portions c are gripped by the arms 10,
The attachment body 2 guides the L-shaped guide body 3 depending.
Then, at this detection station, the side seal portion b of the bag is
In order to detect the defective sticker (there is a piece of champagne),
The light emitter 20 and the light receiver 30 are fixed to the mounting body 2, and the light from the light emitter 20 passes through the perforation hole 3a of the guide body 3 and irradiates the lateral seal portion b of the bag, The transmitted light is received by the light receiver 30.

The projector 20 uses an incandescent light bulb, and the longitudinal direction of the filament is made to correspond to the photodetector 30 so that the photodetector 30 can be irradiated more uniformly.
The irradiation is performed through the ground glass 21 in order to reduce the influence of the filament and perform irradiation as a uniform light source body as much as possible. On the other hand, the light receiver 30 (hereinafter, also referred to as A and B)
Is composed of a pair of photodiodes arranged in parallel with respect to the traveling direction of the bag a, and receives light through the infrared filter 31 in order to reduce the influence of infrared rays. still,
In the case of "shaving bonito" as an object to be encapsulated, if heat sealing is performed while biting into the sealing part, it will melt into polyethylene of the bag material and have a color tone close to a transparent color, but the red part of the shaving bonito is Since it remains slightly, it is an effective means to receive the light through the green color filter having a complementary color relationship in order to make it easy to distinguish the redness. The light receivers A and B are adjusted so as to receive light at the same level from the light projector 20 without the bag a.

Next, the "Kamikomi piece" of the lateral seal portion b of the bag.
The method of detecting the presence or absence of the above will be described with reference to FIG. 3 showing the relationship between the output of each part of the bag a and each part of the detection circuit (FIG. 4) and FIG. 4 showing the block diagram of the detection circuit. In the process of sequentially transporting the bag a, the photodetectors A and B receiving the light from the projector 20 go through the following steps, and the light amount difference between the photodetectors A and B has a waveform as shown in FIG. To be observed. (Step 1) When both the light receivers A and B directly receive the light from the light emitter 20 without the intervening bag a. (Step 2) When the photodetector A receives the vertical seal portion c (and the horizontal seal portion b) of the bag and the photodetector B receives light directly from the photoconductor 20. (Step 3) When both the light receivers A and B receive the vertical seal portion c and the horizontal seal portion b of the bag. (Step 4) When the light receiver A receives the horizontal seal b of the bag and the light receiver B receives the vertical seal portion c of the bag. (Step 5) When both the light receivers A and B receive the lateral seal portion b of the bag. (Step 6) When the photodetector A is receiving a "spotted piece" and the photodetector B is receiving the lateral seal portion b. (Step 7) When both the light receivers A and B receive the "kamicomi piece". However, in this case, it may not exist depending on the size of the chamfered piece. (Step 8) When the photodetector A is receiving the horizontal seal portion b and the photodetector B is receiving the "chamfered piece". (Step 9) When both the light receivers A and B receive the lateral seal portion b of the bag. (Step 10) When the light receiver A receives the vertical seal portion c and the horizontal seal portion b of the bag a and the light receiver B receives the horizontal seal b. (Step 11) When both the light receivers A and B receive the vertical seal portion c of the bag. (Step 12) The light receiver A directly receives light from the light emitter 20,
When B receives light from the vertical seal portion c of the bag. (Step 13) Both the light receivers A and B directly receive the light from the light emitter 20 without the intervening bag a.

In each of the above steps, the difference in the amount of received light between the photodetectors A and B is large, that is, "2", "4", "6", "8", "1".
They are "0" and "12". Therefore, paying attention to these light amount differences, the presence / absence of a "chambered piece" is detected in the detection circuit block diagram shown in FIG.

In this detection circuit, the light receiving signals of the photo detectors A and B are subjected to a difference in light quantity by a differential amplifier, and the difference in light quantity (waveform shown in FIG. 3) is waveform-shaped. Then, when the light amount difference is equal to or larger than the set value set by the level adjustment circuit, a trigger pulse is generated. It should be noted that this trigger pulse is generated when the absolute value of the "light amount difference" is larger than the set value.
"2", "4", "6", "8", "10", "12"
Occurs in. Then, a pulse having a time constant (pulse width) T is generated through the one-shot multivibrator by the above trigger pulse, and this pulse is counted by the pulse counter. The reset pulse of the pulse counter is performed at the timing of transfer to each station and is reset for each bag.

Further, since the time constant T of the output pulse of the one-shot multivibrator is set longer than the time of passing through the vertical seal portion c, each of the steps "2", "6" and "10". However, a pulse is generated by the trigger pulse, but no pulse is generated from the one-shot multivibrator in the stages of "4", "8", and "12". As a result, the number of output pulses of the one-shot multivibrator can be judged to be normal without "came pieces" when there are two pulses generated at the vertical seal portions c at both ends, but when the number of pulses is three or more, " It can be judged that there was a "Kamikomi piece".

In this way, the number of pulses generated in the vertical seal portion c of the bag is reduced to one by using two photodetectors A and B and adopting the one-shot multivibrator (time constant T). As a result, the number of pulses generated in the vertical seal portions c at both ends of the bag is two, and when more pulses are generated,
It can be determined that there was "a piece of paper". Since the time constant T is set to be longer than the time for passing through the vertical seal portion c of the bag as described above, the set value is set corresponding to the width c of the vertical seal and the conveyance speed which differ depending on the size of the bag. change.

Further, the time constant T can be set to be shorter than the time for passing through the vertical seal portion c. In this case,
"2", "4", "6", "8", "10", "12"
At each stage, a pulse is generated by the one-shot multivibrator. Therefore, when 5 or more pulses are counted, it can be determined that there is a chamfered piece, but the number of digits of the pulse counter increases and the configuration of the counter circuit configured by the logic circuit becomes complicated. Further, in the detection circuit (FIG. 3), a “Schmitt trigger” circuit is introduced instead of the “trigger pulse” and the “one-shot multivibrator”, and each of the steps “2” to “4”, “6” to "8", "1"
The pulse can be generated in response to the changing pulse of "0" to "12". In this case, when the number of counted pulses is two, it is normal, and when the number of counted pulses is three or more, there is a "kamikomi piece". or,
In each of the above, the trigger pulse is generated when the absolute value difference between the photodetectors A and B is equal to or more than the set value, but by setting only one side value,
"2", "6", "10" (or "4", "8",
It is also possible to configure to generate the trigger pulse only in the step of "12").

The detection circuit (FIG. 3) has a display (either of the light receivers A and B) for displaying the deviation of the optical axis through the waveform shaping and the optical axis detection circuit of the output of the differential amplifier. Is displayed in four steps). Therefore, the operator can easily set the photodetector A and the photodetector B so that they can receive light at the same level while looking at this display. Further, even when the light bulb of the projector 20 is out, a bulb out is displayed, which contributes to early detection of defective products.

[0015]

The method for detecting a defective seal portion according to the present invention is more accurate because it detects a pulse by generating a pulse through the difference in the amount of light received by the pair of light receivers A and B. be able to. Further, by setting the pulse width T generated by detecting the difference in the amount of light received by the photodetectors A and B to be longer than the time required to pass through the vertical seal portion, the number of pulses generated in the vertical seal portion is one. Therefore, the defective seal portion can be detected more easily.

[Brief description of drawings]

FIG. 1 is a plan view of a detection station.

FIG. 2 is a side view of FIG.

3 is a diagram showing a relationship between each part of the bag a and an output of the detection circuit shown in FIG.

FIG. 4 is a block diagram of a detection circuit.

[Explanation of symbols]

 a bag b horizontal seal part c vertical seal part 3 guide body 3a transmission hole 20 projector 30 (A, B) light receiver

Claims (2)

[Claims] 1. A bag which is transported after an opening is laterally sealed after a package having been put into a bag having both vertical sealing portions and is gripped by both vertical sealing portions and gripped by an arm. In the method of irradiating a photon to the lateral seal part and receiving the transmitted light by the photodetector to detect a defective seal, two photodetectors are arranged side by side in the traveling direction of the bag, and the photodetectors of the photodetectors are received. A method in which a pulse is generated when the difference in amount is equal to or greater than a set value, and whether or not there is a defective seal portion is detected by the number of pulses. 2. The method for detecting a defective seal portion according to claim 1, wherein the pulse width generated in claim 1 is set longer than the time required to pass through the vertical seal portion.