JPS63191727A - Method and device for detecting defective sealing of packaging bag - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) This invention provides a packaging bag filled with a product that has good sealing properties.
The present invention relates to a method and device for detecting defects.

(Prior Art) Japanese Patent Laid-Open No. 61-81930 discloses a method and device for detecting whether sealing performance is good or bad in a sealed packaging bag whose m1 opening is sealed after filling with contents.

As shown in FIG. 8, this invention involves storing a sealed packaging bag (a) filled with contents in a tray (31), and inserting a hollow made of a non-stretchable film from above or below the tray (31). The body (32) is lowered by a certain stroke (S) from a reference height P) and presses the upper surface of the packaging bag (a) to a predetermined level! - Press the valve (S+) to increase the internal pressure of the room (a). The repulsive force due to the internal pressure of the packaging bag (a) is applied to the hollow body (32), and based on the pressure change characteristics generated inside this hollow body (32), it is possible to detect whether the sealing performance of the packaging bag (a> is good or bad). It is.

Since the above-described invention detects whether the sealing performance of the packaging bag (a) is good or bad in the above manner, the following three points are important conditions.

1. The amount of air contained within the sealed packaging bag, that is, the air content, must always be constant.

2. The volume of the contents must be constant.

3. There should be no variation in the size of the bags.

However, actual packaging bags (a) always have variations in the above points, especially in terms of air content.
This variation in air content appears as a difference in the thickness of the sealed packaging bag (a).

Therefore, as shown in FIG. 9, when inspecting a thick packaging bag (a') with a higher air content than the standard using the above-mentioned apparatus, the hollow body (32) presses the top surface of the packaging bag (a'). Since the straw rate (Sl) from the start to the lowest position is larger than that of the sealed packaging bag (a) with standard air content, the pressure value detected in the hollow body (32) becomes higher, and When inspecting sealed packaging bags with low air content (not shown),
Contrary to the case described above, since the stroke (Sl) becomes smaller, the test pressure value becomes smaller.

However, the device that refuses the test is one in which the air content of the packaging bag (a) to be inspected is
When increasing or decreasing the air content φ of the packaging bag (a) as a standard,
The individual pressure values detected by the hollow body (32) also vary widely, and it is difficult to distinguish pressure changes due to pinholes or poor sealing, so the usage conditions are severe and it is not practical.

(Technical Problem) The technical problem of the present invention is based on the premise that there are variations in air content, etc. in the packaging bags to be actually sealed, and to investigate the variations in the pressure values measured when the packaging bags are pressed. Another object of the present invention is to provide a method and device for detecting sealing defects that can keep pressure changes due to pinholes and sealing defects within a discernable range.

(Means for solving the technical problems) The means taken by the first and second editions to solve the above-mentioned technical problems are as shown below.

The first invention comprises a thickness measuring step in which a sealed packaging bag whose contents are flattened is moved along a transfer path and the thickness of the packaging bag is measured on the way; and the thickness measured in the step. This process consists of a detection process in which the packaging bag is pressed with a certain stroke based on the sealing temperature, and whether the sealing state is good or bad is determined based on the pressure change characteristics that occur in the bag.

The second invention provides a thickness measuring device on a conveyor that transfers sealed packaging bags at regular intervals, a pressure-sensitive detector on the downstream side, and electrically connecting the two via an output control section. The thickness measuring machine measures the thickness of the packaging bag with a position detection head that presses against the top surface of the packaging bag and moves up and down, and the pressure-sensitive detector presses the top surface of the packaging bag when the pressure-sensitive head that moves up and down descends. Based on the pressure change characteristics that occur in the bag, it is determined whether the sealing state is good or bad, and the output control unit moves the pressure-sensitive head to the top surface of the bag from the thickness position based on the thickness value sent from the thickness measuring device. This is to control the output to lower it by a constant stroke.

(Operation) According to the means of the first invention, the thickness and height of the packaging bag whose contents are flattened are measured while moving on the transfer path,
A constant stroke of pressure is applied based on the thickness. At the time of pressing, the pressure change occurring within the packaging bag is measured, and based on this, it is determined whether the packaging bag is well-sealed or not.

According to the means of the second invention, the contents of the packaging bags placed on the conveyor at regular intervals are flattened,
The position detection head is attached to the top surface and presses against it, and the thickness and height at which the internal pressure begins to increase is measured.

The measured bag thickness is input to the output control section as an electrical signal. When the bag whose thickness was measured moves to the pressure measurement position, the output control unit sets the pressure-sensitive head of the pressure-sensitive detector to the height of the measured bag based on the input thickness data. and lower it by a constant stroke.

The pressure inside the sealed packaging bag pressed by the pressure-sensitive head increases at a rate corresponding to the sealing performance, and is increased to approximately a predetermined value after a predetermined time. If the packaging bag has a defective bottle ball seal or the like, the pressure inside the packaging bag increases at a lower rate of increase than in the case of a good product, and after a predetermined period of time, it reaches a lower value than the predetermined value.

The pressure-sensitive detector uses a pressure-sensitive head to sense the above-mentioned pressure change inside the bag, and based on the data characteristics, determines whether the sealed state of the sealed packaging bag is good or bad.

(Eri) As described above, the first invention presses the packaging bag with a constant stroke based on the measured thickness of the packaging bag, so even if there is variation in the air content of the packaging bag, The pressure value generated within the packaging bag is kept constant, and it is possible to reliably determine whether the sealed state is good or bad based on the pressure change during pressing.

Since the second invention is as described above, the thickness of the bag is detected by pressing the position detection head against the top surface of the packaging bag moving on the conveyor, so that the thickness of the packaging bag is detected when the internal pressure starts to increase. It is possible to accurately measure the

Since the pressure-sensitive head is pressed against the top surface of the packaging bag in a fixed stroke based on the thickness measured as described above, even if there is variation in the air content of the packaging bag, each By keeping the pressure value generated inside the bag constant, it is possible to reliably determine whether the sealing state is good or bad based on the change in pressure inside the bag during pressing.

(Example) Hereinafter, one embodiment of the present invention will be described based on the drawings.

(A) shown in FIG. 1 is a sealing failure detection device implementing the second invention; a conveyor (1) on which a sealed packaging bag (a) is placed and transferred; It consists of a thickness measuring device (2) provided on the starting end side, a pressure sensitive detector (3) provided downstream of the thickness measuring device (2), and an output control section (4).

The conveyor (1) is endless, and product placement sections (1C) partitioned by partition plates (1b) are provided at regular intervals on the surface of the belt (1a). The wrapped and hermetically sealed packaging bag (a) is transferred to the conveyor (1
) 1 on the product placement section (1C) that has rotated to the starting end side.
When placed one by one, they are transferred at a constant speed to the end of the conveyor (1) at regular intervals.

The thickness measuring machine (2) measures the thickness of the packaging bag (a) placed on the conveyor (1) and transferred, and is installed above the starting end side of the conveyor (1). .

As shown in FIG. 2, the thickness measurement 1jl (2) is performed using a substantially ski-shaped position detection head ( The position detection head (2a) is pivotally attached to the tips of link rods (8) (8') whose proximal ends are pivotally supported on the base plate (7), and the belt (2a) of the conveyor (1) is equipped with a 1a) It is designed to move up and down while remaining parallel to the plane. In addition, by pulling the link rod (8) on the starting end side of the conveyor (1) to the starting end by the spring (9), the position detection head (2a) is always directed downward (=j force), and the link rod (8) ) is stopped by a stopper bin (24) in a position facing straight down, and the position detection head (2a) is stopped at a position somewhat lower than the thickness and height of the packaging bag (a).

The conveyor (1) is placed under the position detection head (2a) mentioned above.
When the packaging bag (a) placed on the packaging bag (a) passes through the packaging bag Ca>
The position detection head (2a) is pressed against the upper surface of the
The thickness of the packaging bag (a), that is, the thickness of the packaging bag (a) when the position detection head (2a) is in pressure contact with the belt (1a) surface.
) The height to the top surface is measured.

In addition, the position detection head (2a) with respect to the top surface of the packaging bag (a)
The pressing force of the bag (a) is the pressure of the measuring plate (2a).
) The setting is such that the internal pressure begins to increase.

The measuring plate (2a) then passes through the packaging bag (a).
a) Thickness above the valve? Then, with this rise, the link rod (8') at the end of the conveyor (1) rotates, and this rotation also causes the gear (8') attached to the shaft support of the link rod (8') to rotate.
10) of the rotary encoder (11).
12).

The rotary encoder (11) converts the amount of rotation of the main @ (12) into an electrical signal, and therefore the measuring plate (2)
The thickness of the packaging bag (a) measured in step a) is converted into an electrical signal by the rotary encoder (11), and this signal is input to an output control section (4) to be described later.

The thickness measurement mentioned above! ! A pressure sensitive detector (3) is installed downstream of 1 (1).

The pressure sensitive detector 3) is mounted on the base (6) and the pressure sensitive head (3a)
Back-down drive that supports (3a”) so that it can move up and down! 3
(3b) (3b') are installed in parallel with the same width as the interval between the product placement parts (1C) of the conveyor (1), and the base (6) is placed along the conveyor (1). Both pressure-sensitive detectors (303 ') moves directly above the packaging bag (a) being transferred by the conveyor (1), and the slide rail (5) (
At the end of step 5), turn back and move back and forth in one stroke.

The pressure-sensitive heads (3a) (3a') supported by the lift drive panels (3b) (3b') so as to be able to rise and fall are attached to the conveyor (1).
It is a device that detects the pressure change that occurs in the packaging bag (a) when it is pressed against the top surface of the packaging bag (a) being transferred at the same time, as shown in Fig. 4. WJ made of sponge or the like on the lower surface of a rigid pressure plate (13) formed into a plate-like body of the same size! Elastic layer for f1 buffer (14
) and then pressure sensitive 4? on the bottom surface of the same layer <14). lf
f1 rubber (15), and a soft and durable mesh layer (16)
) are layered in order, and the lifting drive panels (3b) (3b'
) is installed horizontally at the lower end of the lifting rod (17).

The pressure-sensitive conductive rubber (15) described above has a characteristic that the electrical resistance value decreases by 1° in inverse proportion to the pressing force applied to the rubber (15). Therefore, pressure-sensitive conductive rubber (15)
When the pressure-sensitive heads (3a>(3a') are pressed against the top surface of the packaging bag (a) after energizing the Rubber (15
) increases or decreases in proportion to the pressing force.

The pressure sensitive conductive rubber (15) electrically communicates with the discrimination function section (23), and inputs the current value passing through the pressure sensitive conductive rubber (15) to the discrimination function section (23).

The discrimination function section (23) detects the change in the value of the current flowing through the pressure-sensitive conductive rubber (15) when pressure is applied inside the packaging bag (a), that is, the change in the value of the current flowing inside the pressed packaging bag (a). It has a function of determining whether the packaging bag (a) is in a good or bad sealed state based on the change.

On the other hand, the lifting rod (11) that holds the pressure-sensitive heads (3a) (3a') described above has a threaded portion (17a) formed on the upper end side, and is supported by the rod support (18) so that it can be raised and lowered in a non-rotatable state. are doing. The threaded part (17a) has a rod support (18
) and the suspension gear (20) held between the receiving plate (19) are screwed together, and the lifting rod (11) and the pressure sensitive head (3a) (3a'') are screwed together.
is suspended by the suspension gear (20), and the suspension #
It is constructed by meshing the i4 wheel (20) with the main shaft gear (22) of the stepping motor (21). As a result, when the stepping motor (21) is rotated forward and backward, the suspension gear (20) is rotated forward and backward, and the lifting rod (11) is rotated forward and backward.
) The pressure sensitive heads (3a) (3a') supported by the pressure sensitive heads (3a) (3a') are designed to move up and down.

The stepping motors (21) of both pressure-sensitive detectors (3) (3') are electrically connected to the output control section (4), and are sensed by the output filI control of the output control section (4). It controls the lowering timing, lowering stroke, and timing of the pressure heads (3a) (3a'). Note that any type of stepping motor (21) may be used as long as its rotation can be controlled step by step.

Therefore, the above-mentioned thickness measuring machine (2) and both pressure sensitive detection 1 m (
3) A thickness measuring machine (2) is electrically connected to (3') through an output control unit (4) and measures the thickness of the packaging bags (a) that are transferred one by one by the conveyor (1). The thickness data is sequentially input to the output control section (4). The output control unit (4) links the transfer speed of the conveyor (1) with the reciprocating cycle of the base (6), and also controls both pressure-sensitive heads (3a) based on the thickness data of the packaging bag (a) described above. and (3a') to control the descent height, suppression stroke, and rise/fall timing.

Next, a method for detecting a seal failure according to the first invention will be explained based on the seal failure detection apparatus (A) described above.

The method for detecting sealing defects of the second invention includes a thickness measuring step of measuring the thickness of the packaging bag (a) moving along the transfer path, and a packaging bag ( a)
This consists of a detection step in which the sealing state is determined to be good or bad based on the pressure change that occurs in the special device (a) by pressing the special device (a) with a constant stroke.

In the thickness measurement process, the conveyor (1) is the transport path for transferring the packaging bag (a>), and the means for measuring the thickness is the thickness measurement!11 (2).

On the product placement part (1C) which rotates and moves sequentially to the starting end of the transfer path of the conveyor (1), a packaging bag (a) filled with contents (b) such as Snack Toko and sealed hermetically is placed.
The products are placed one by one using a product feeder (not shown) or the like, and are transferred at a constant speed to the terminal end of the conveyor (1) at regular intervals. The contents in the packaging bag (1) placed on the bell I-(la) of the conveyor (1) are flattened and
) is also approximately flat.

The packaging bag (a) is placed in the position detection head (2) of the thickness measuring machine (2).
When trying to pass under a), the head (2a) rides on the upper surface of the collision (a) while being pressed against it with a predetermined pressing force,
The position detecting head (2a) is pushed up to the height of the packaging bag (a) in a pressed state.

When the position detection head (2a) is pushed up, the link rod (8') rotates by an angle corresponding to the thickness of the packaging bag It is transmitted to the main shaft <12) of a tally encoder (11), and the rotary encoder (11) converts the thickness of the packaging bag (a) into an electrical signal, and this signal is input to the output control section (4).

The means for pressing the packaging bag (a) into the detection process are pressure-sensitive heads (3a) (3a') and arm-lowering drive boards (3b) (3b') that raise and lower these heads, and the thickness measurement process The output control unit (4) causes the pressing means to press the packaging bag (a) with a constant stroke based on the thickness measured in , and the sealing state is determined based on the pressure change that occurs inside the packaging bag (a) during the pressing. It is the determination function section (23) of the pressure sensitive detector (3) that determines whether the product is good or bad.

As mentioned above, the reciprocating movement and vertical movement of the pressure sensitive heads (3a) (3a') are controlled by the output control section (4), and the packaging bag (a) whose thickness has been measured is transferred to the conveyor (1).
) on both pressure-sensitive heads (3a) (3a')
When the starting end side descending position fffld) (e) is reached, the terminal end side ascending position (f') (Q) to the above descending position (d)
The pressure sensitive heads (3a) (3a') that have been moved in (e) are lowered and moved toward the terminal end.

As a result, both pressure-sensitive heads (3a) (3a') follow the target packaging bags (a) (a), and
Packaging bags (3a) (3a) until reaching the raised position (f) (q)
') Press the top surface with a predetermined stroke, and 1.
There is even one in which the robot is raised at the W position (f) (g) and at the same time quickly turned toward the lowered position (d) (e), and thereafter repeats the above-described cycle.

The downward stroke of the pressure sensitive head (3a) (3a') is
The pressure generated inside the packaging bag (a) when pressed is
In order to keep it constant, it is set according to the thickness of each packaging bag (a), and is based on the thickness data of each packaging bag (a) measured by the thickness measuring machine (2) mentioned above. It is controlled by the output control section (4).

The setting of the descending stroke of the pressure-sensitive heads (3a) (3a') will be explained based on FIG. )
The data is input to the control unit (4).

Both packaging bags (a+) (a2) move on the conveyor (1) and the pressure sensitive heads (3a) (3a') descend to the position (d).
When reaching (e), both pressure sensitive heads (3a) (3a'), which had turned while going up and down from the end side, also returned to the lowering positions (d) and (e), and immediately released both packages. Bag (a+) (
It moves to the terminal side at the same speed as a2) and begins to descend.

The upper position (P) of the pressure sensitive head (3a) (3a') is at a certain height 1 from the belt (1a) surface of the conveyor (1).
), and both pressure sensitive heads (3a) (
3a') is to lower the upper limit position (P) by a predetermined stroke.

The predetermined descending stroke marked F is the distance 11i (St
> and the pressing stroke (Sl), which is the length S), and the pressing stroke (Sl) is set to generate a predetermined pressure in the packaging bag (a), and the pressing stroke (a) is constant. It is something to do.

In addition, the distance (Sl) from the rising position ffi (P) to the top surface of the packaging bag (a) is
a) They are individually responsible. In the present invention, a change in air content 1 is regarded as a change in the thickness of the bag (a), and upper dorsal position i? ff (
Thickness data of bag (a) input from P) (
Calculate (Sl) by subtracting tl) (c) Add the above-mentioned (Sl) to this to calculate the descending stroke 1 for each packaging bag (a).
]-ri(S) is set.

As a result, even if there are variations in air content M (thickness), such as the packaging bag (a) to be tested for sealing and the packaging bag (a + Ha2) shown in Figure 6, these packaging bags (a
+ ) (a2), the individually measured thickness position (j +
) can be pressed by the set pressing stroke (Sl). Therefore, the pressure sensitive head (3a) (3a'
), a constant pressure is always generated in the packaging bag (a), and it is possible to reliably determine whether the sealing performance is good or bad based on this pressure change.

As mentioned above, when the packaging bag (a) is pressed and the pressure inside the bag (a) increases, the repulsive force accompanying this pressure
Press the pressure-sensitive conductive rubber (15) of the pressure-sensitive head (3aH3a'). When pressure is applied, the pressure-sensitive conductive rubber (
The resistance value of the conductive rubber (15) decreases, and the value of the current flowing through the conductive rubber (15) changes in proportion to the pressure applied to the rubber (15). This current value change characteristic is determined by the discrimination function section (23
) is input as the change in pressure occurring in the packaging bag (a), and the packaging bag <a> is inspected based on this pressure change characteristic.
It is determined whether the sealing performance is good or bad.

The graph shown in FIG. 7 shows the pressure sensitive head (3a) (3a')
) The basic patterns ■ to ■ of the pressure increase characteristics inside the packaging bag (a) detected by is taking.

■ is the case of packaging bag (a) which has a high degree of sealing and is relatively thin (few air gaps); when a pressing command is given at 1°, the actual pressure starts at tl, and at t3 The pressure of Ps is reached at . In this case, since the sealing performance is high and the air content is small, the rate of increase in pressure is high, and the time required to actually perform the opening 4 while being pressed is short.

■ is a packaging bag with a high degree of sealing and a relatively thick thickness (a
), the pressure increase rate is almost the same as in case (■), but because there are many air gaps, the time until pressurization starts is slow,
As a result, the pressure at t3 is R4, which is lower than ■.

■ is a case of a packaging bag (a) with a low degree of sealing and a thin thickness; it is pressurized from tl, but since the degree of sealing is low, air leaks during pressurization, the pressure rate is low, and t3 The pressure at this time is as low as R3.

Case (2) is the case of the packaging bag (a) which has a low degree of sealing and is thick, and since there are many air gaps, it takes time to start pressurizing, and the pressure rate is low, so the pressure at t3 is R
2, the lowest.

Good sealing performance of packaging bag (a) measured by pressure change.

Defects are determined based on P/, that is, the pressure and the rate of increase in temperature. For example, if the pressure value Pffi after t3 is within the range of P4 to Ps, the sealing performance is considered to be good. If it comes off, it is determined that the seal is poor.

It is also possible to detect the amount of air in the packaging bag (a) by measuring the time from when the suppression command is issued to when pressurization actually starts by 1 m.

The above-mentioned discrimination is performed before the pressure-sensitive head (3a) (3a') reaches the upper boundary position fa (f') (a), and the packaging bag (a) whose sealing performance is good is determined by the pressure-sensitive head (3a) (3a'). a) is transferred to the end, and J2 is a packaging bag in which poor sealing was detected (
In a), after the pressure sensitive heads (3a) (3a') turn to the starting end side, they are dropped onto a predetermined storage location from above the reconveyor (1) by a defective product removal device (not shown), or are protruded. The conveyor is then transferred to another conveyor.

Note that the pressure sensitive heads (3a) (3a') described above may be increased to three or more, or may be reduced to one (not shown).
, if there is only one packaging bag (a) to be inspected, place the head (3) next to it and place it next to each other, then place the bag at 172 between the product loading part (1C).
The sealing property is determined before the bag is transported a distance of , and the cycle r in which the next packaging bag <a) immediately rises and turns once until it reaches the above-mentioned adjacent lower position is detected.

Roughly, the pressure-sensitive head (3a) may be fixedly installed as shown in FIG. It is also possible to use a recycle to lower the head (3a) after stopping.

In addition, packaging bags (a) that have undergone a sealing inspection are packed into a cardboard box or the like in a certain number of stacks, but if bags (a) that are thicker than the specified number are inserted, it will be difficult to accommodate them, and if the bag is thinner than the specified number, it will be difficult to accommodate them. If it gets inside, a gap will open and the packaging bag will move during transportation, so it is necessary to control the thickness of the bag to some extent.

The above-mentioned device (A) uses the thickness measuring section (2) to measure the packaging bag (
Since the thickness of a) can be measured, by removing the packaging bag (a) whose thickness falls outside the predetermined range, the thickness of the packaging bag (a') can be controlled at the same time as the sealing inspection is performed. You can also do that.

[Brief explanation of the drawing]

Fig. 1 is a front view showing a seal failure detection device implementing the second invention, Fig. 2 is a partially cutaway enlarged front view of the thickness measuring section, and Fig. 3
The figures are (IIIi (DI)) sectional view of Fig. 2, Fig. 4 is a vertical sectional side view of pressure-sensitive detector n, and Fig. 5 is a pressure-sensitive detector equipped with one fixed pressure-sensitive head. A front view, FIG. 6 is an enlarged front view of the pressure-sensitive head section showing the relationship between rotation and rotation, FIG. 7 is a graph showing changes in pressure generated in the packaging bag over time during pressing, and FIGS. 8 and 9. is a front view showing a conventional sealed detection device suppression mechanism.

Claims (2)

[Claims] (1) A thickness measurement process in which the sealed packaging bag with the contents flattened is moved along the transfer path and the thickness of the packaging bag is measured on the way, and the thickness measured in this process is A method for detecting poor sealing of a packaging bag, which comprises a detection step of pressing the packaging bag with a certain stroke based on a standard, and determining whether the sealing condition is good or bad based on the pressure change characteristics generated on the bag. (2) A thickness measuring device is provided on the conveyor that transfers the sealed packaging bags at regular intervals, and a pressure-sensitive detector is provided downstream of the device, and both are electrically connected via an output control section. The thickness measuring machine measures the thickness of the packaging bag with a position detection head that presses against the top surface of the packaging bag and moves up and down, and the pressure-sensitive detector presses the top surface of the packaging bag when the pressure-sensitive head that moves up and down descends.
Based on the pressure change characteristics that occur in the bag, it is determined whether the sealing condition is good or bad, and the output control unit moves the pressure-sensitive head from the thickness position to the top surface of the bag at a constant stroke based on the thickness value sent from the thickness measuring device. A packaging bag seal failure detection device that controls the output of lowering.