JP2517835B2 - Automatic packaging machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention draws a packaging film rolled into a roll, inserts an article to be packaged between them, melts the film at a predetermined position and simultaneously welds it to form a bag, The present invention relates to an automatic packaging machine for packaging articles to be packaged, and more particularly to an automatic packaging machine provided with a sealing device capable of reliably welding upper and lower films on side edges of the articles to be packaged regardless of the shape and size of the articles to be packaged.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Utility Model Publication No. 62-1842
As disclosed in Japanese Unexamined Patent Publication No. 9-9, there is known an automatic packaging machine using a two-fold film developed and put to practical use by the present inventors. In this automatic packaging machine, the L-shaped sealing device having a film fusing and welding blade simultaneously seals the opening in the direction orthogonal to and the direction parallel to the folding direction of the double-folded film.

By the way, in order to surely weld the two films at the same time as the fusing, it is important that air is not interposed between the two films at the fusing and welding portion. If air is interposed between the films of the fusing and welding part, a peeling part occurs between the films in the working part of the fusing and welding blade, and the fusing and melting are performed without welding between the upper and lower two films. As a result, a so-called pinhole phenomenon in which sealing is not partially performed occurs, and the sealing is incomplete.

[0004] In particular, in the case of the above-mentioned L-shaped sealing device, since the longitudinal and lateral directions of the film flow are fused and welded at the same time, the air existing between the two-fold films during sealing is confined in the sealing portion and becomes a high pressure. Attempts to expand the sealing surface between the films. Furthermore, if the packaging is to be performed by the L-shaped sealing device with the film attached to the article to be packaged as much as possible, particularly when the article to be packaged is high, the film itself must be greatly deformed. Become. Such a situation creates an incomplete seal for the reasons described above. Therefore, conventionally, a film retainer was attached to both sides of the fusion welding blade, and both sides of the fusion welding line were sandwiched between this film retainer and the seal pedestal to eliminate the air present between the films and cause the fusion welding. However, it is difficult to make the two films existing between the film holders in perfect contact with such mechanical pressing even if they are machined with high precision, and the above problems are still avoided. Often impossible to do. Therefore, in order to increase the distance between the seal line and the article to be packaged, it is usually necessary to use an unnecessarily wide film, which not only impairs the appearance of the package, but also increases the film consumption. .

On the other hand, as an automatic wrapping machine which employs a sealing device other than the above-mentioned L-type sealing device, two long films are superposed on each other, or an article to be packaged is accommodated between the two folding films as described above. However, a method is known in which the front and rear seals in the film flow direction and the left and right side edges or one side edge seal are individually formed. A so-called I-seal device that uses a linear heat bar is known as the front-rear sealing device, and as a side edge sealing device, for example, two films are formed by a pair of left and right endless belts sandwiching a seal line. There is known a device for fusing and fusing two films with upper and lower sealing disks that rotate along a sealing line between the left and right belts while being conveyed while being sandwiched. According to the sealing method of separately performing the front and rear seal and the side edge seal, at least one of the front and rear or left and right side edges of the film is always in the open state at the time of any preceding seal. Is less affected by the air present in the L-type sealing device.

Furthermore, without fusing welding by the heating means, simply by charging static electricity to the left and right film, pillow packaging machine for fusion bonded to the opening edge portions of the left and right <br/> film of that is,
For example, it is disclosed in Japanese Utility Model Publication No. 64-23405 .

[0007]

However, even in the packaging machine in which the front and rear seals and the side edge seals are separately provided by fusing and welding, both sides of the film sandwiching the seal line are mechanically pressed by a film retainer or an endless belt. It is adhered by the pressing force, and in the seal part which is the intermediate part, the two films are still in a peeled state, and there is a gap between them, so it is impossible to completely avoid the occurrence of the above-mentioned pinhole. Is the actual situation.

Particularly, in the above-mentioned side edge sealing device, the side edges of the film to be sealed are clamped by the pair of upper and lower endless belts so as to closely contact each other.
In order to obtain uniform adhesion, it is necessary to press the upper and lower belts on the film running side from above and below, but it is not possible to set a uniform adhesion mechanism because the upper and lower sealing disks are arranged between the left and right endless belts. Extremely difficult.

In addition, in this type of automatic continuous packaging machine, the film must be stopped once when it is sealed at least in the direction orthogonal to the film flow direction.
At this time, it is necessary to temporarily separate the upper and lower seal disks from the film surface. If the sealing disc is not separated from the film surface, the two film portions sandwiched by the upper and lower sealing discs will be fused and not welded in the separated state, and the portions will not be sealed.

On the other hand, in the electrostatic seal disclosed in Japanese Utility Model Laid-Open No. 64-23405 , the upper and lower films are
It is temporarily joined by static electricity and at the same time fusing and welding.
However, in particular, the fusing means is a simple disc.
Therefore, it is necessary to provide welding means independently of the fusing means.
There is a point.

The present invention eliminates the above-mentioned drawbacks at the time of sealing by the fusing and fusing technique that exhibits a reliable sealing function in the related art, utilizes the film adhesion function by electrostatic charging, and adopts a simple structure, and The opening of the heat-welding film that encloses the article to be packaged in a state where the upper and lower films are evenly adhered to each other without applying unnecessary pressing force or tension, especially the opening edge parallel to the film flow direction An object of the present invention is to provide an automatic packaging machine equipped with a sealing device that melts and welds a single member.

[0012]

In order to achieve this object, the first aspect of the present invention relates to a film roll of a packaging film wound into a roll and a film drawn from the film roll of a packaged article. A film opening device that opens in a wrappable shape, a packaged article conveying device that introduces an article to be packaged between the films opened by the film opening device, and a device that is installed adjacent to the downstream end of the packaged article conveying device And a sealing device for welding the film opening edge portion, wherein the sealing device has at least a welding means for welding the opening edge portion parallel to the film flow direction, and It is provided with electrostatic charging means in proximity to the opening edge between leading to the welding means from the vicinity of the fill of the welding means
Press at least the welded edge of the film to the downstream side of the frame.
While a pair of upper and lower feed rolls are installed,
The welding means projects from the heating unit body and the lower end of the heating unit body.
However, the vertical position can be adjusted together with the main body or independently.
Is gradually narrowed toward the lower end and directed forward.
And then project downward from the running surface of the thin film.
A heating plate that is melted and welded continuously in a stabbed state .

A second aspect of the present invention is a film roll of a packaging film wound into a roll, and a film opening device for opening the film drawn from the film roll into a shape capable of packaging the article to be packaged. , A packaged article conveying device for introducing a packaged article between the films opened by the film opening device, and a sealing device which is installed adjacent to a downstream end of the packaged article conveying device and welds a film opening edge portion In the automatic wrapping machine having the above, the sealing device has a welding means for welding at least an opening edge portion parallel to the film flow direction, and the sealing means between the vicinity of the packaged article conveying device and the welding means. close to the opening edge portion becomes to electrostatic charge means are provided, said
On the downstream side of the film of the welding means, at least the film
A pair of upper and lower feed rollers that pull out while pressing the welding edge.
Is installed on the edge of the film facing the welding means.
Part of the welding means, the welding means
It is a heating pressure roll that seals points along the rule line.
Characterized in that that.

[0014]

The operation of the present invention will be described by taking the case of automatic packaging using a folded film as an example . When the packaged article is placed on the packaged article conveying device and the automatic wrapping machine is activated, the film feed roll starts to rotate, the bi-fold film is pulled out from the film roll, and the traveling direction is changed by 90 ° by the film opening device. The front and back are reversed, and at the same time, the bi-fold film travels to the first sealing device while opening in a U-shaped cross section. At this time, the articles to be packaged placed on the packaged article transport device driven through the opening of the two-fold film are sequentially introduced between the upper and lower films.

When the film portion containing the article to be packaged between the upper and lower films reaches the first sealing device from the article-to-be-packaged conveying device, the edge portion on the side of the opening is fed out to the downstream side while being sandwiched by the feed roll from above and below. . The film passing through the feed roll is charged by the electrostatic charging means, which is the most characteristic feature of the present invention, prior to the fusing and welding, so that the opening edge portions of the upper and lower films are brought into close contact with each other uniformly.

The adhesion at this time is due to electric attraction and not due to mechanical external force such as a film presser or a belt, so that the adhesion is not easily peeled off, and the adhesion is maintained at a predetermined level. It is possible to make uniform contact with the width of, and unexpectedly, this adhesion performance does not deteriorate even by heating. As a result, the seal portion of the film maintains a uniform contact state with a certain width at least until it passes through the fusion welding means, and the air existing between the upper and lower films is completely eliminated in the seal portion. And simple as above
Even with simple welding means consisting of a structure, reliable welding
Sometimes it is possible to exert the fusing function .

That is, between the front and rear feed rolls, the width is gradually narrowed toward the lower end which is the welding means, and the film is formed.
A fill film that is gradually thinned toward the front in the upstream direction.
Continuous welding by piercing downward from the running surface
A heating press for point-sealing along the heating plate or seal line.
The pressure roll acts to cause welding and welding along the seal line at the opening side edge parallel to the running direction of the film. this
At this time, the film is pierced by the welding means while
We will let RUM run and perform melting and welding at the same time
However, for example, when the welding means is the heating plate,
Since the hot plate gradually becomes thicker on the downstream side of the film,
Make sure that the fusing end of the rum is welded .

In this way, when the one side edge of the film is sealed by the first sealing device for a predetermined length, the front end of the film is in the sealed state in the previous packaging, and the articles to be packaged contained in the film are When the rear seal line that traverses the film reaches the second sealing device, the drive of the feed roll and the packaged product unloading device is temporarily stopped, and the film transfer is temporarily performed. Stop.

When the transfer of the film is stopped, the fusing blade is lowered toward the seal receiving base of the second sealing device, and the upper and lower films are fused in the transverse direction along the rear seal line of the film at the same time as the fusing. To do.

Further, on the first sealing device At the same time
The fusing and fusing means ascends and retracts from the film contact position.
Alternatively, it may be stopped at the same position . This is because there is no fear of increasing unnecessarily melting area of the remainder off Irumu even during the stop of the film. When the welding of the film rear end portion by the second sealing device is completed,
Again, all the operating members such as the packaged article conveying device, the packaged article unloading device, and the feed roll start operating,
The heating rod of the first sealing device is also lowered to the film contact position, and the side edge sealing for the next article to be packaged is started in the same manner as above. The packaged articles that have been packaged are discharged by the packaged article unloading device, and if necessary, pass through a heat tunnel to shrink the film.

According to the present invention, in the first sealing device, the side edges of the upper and lower films are brought into close contact with each other by the electrostatic charging means, and the heating plate or the point sealing means has a predetermined shape.
At the position, the side edge part is melted and the fusing edge is moved to the left and right.
Make sure to weld the side edges while separating. Especially the first
A pair of upper and lower feed rolls is installed following the fusing and welding means of the sealing device, and the fused film end is blown by the roll pair, so that the fused film end is flattened and welded by pressing, and simultaneously cooled. As a result, the seal becomes more reliable. In addition, since the seal length of the first sealing device can be set arbitrarily, it is possible to package long and narrow items to be packaged or items to be packaged having different lengths with a single machine, unlike the conventional L-type sealer. Can be miniaturized.

[0022]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 5 show an automatic packaging machine according to a first embodiment of the present invention. Although the present embodiment is an example of an automatic wrapping machine that seal-wraps an article to be packaged using a bi-fold film, the present invention is not limited to a bi-fold film, and for example, two sheets of film are superposed and an article to be packaged is provided therebetween. The present invention can be naturally applied to an automatic packaging machine in which the front, rear, left and right openings of the same article are continuously melted and welded while being sequentially inserted.

In the illustrated example, the first sealing device 1 which is a feature of the present invention, which seals the opening parallel to the flow direction of the half-folded film 5 by fusing and welding, and the first sealing device 1 for the article to be packaged. To transport the article to be packaged, which is a transporting device for feeding the film roll 3, to the film roll 3, a film feeding portion 6 that feeds the folded film 5 from the film roll 3, and an opening that allows the film 5 to be wrapped. The film opening device 4 and the second sealing device 10 that is disposed close to the downstream side of the first sealing device 1 and that melts and welds the opening at right angles to the film flow direction.

The bi-fold film 5 is wound into a roll to form the film roll 3. However, it is also possible to use a film roll obtained by winding a wide film into a roll. In this case, it is necessary to install a film folding device between the film roll and the film opening device 4.

The film opening device 4 has a well-known mechanism to reverse the folded film 5 and to open it in a U shape at the same time to open it, and a pair of upper and lower guide plates having an isosceles right triangle shape. 7 and 8 and columns 9 for holding the same, and the article-conveying belt 2 to be packaged has upper and lower guide plates 7,
It is arranged in a state of being inserted between the eight. Upper and lower guide plates 7, 8
Are provided in parallel to each other with respect to the article-conveying belt 2 to be packaged. Further, the oblique sides 7a and 8a of the guide plates 7 and 8 are arranged so as to form an angle of 45 ° with respect to the traveling direction of the article-to-be-packaged conveyance belt 2, and the two-fold film in a close contact state fed from the film roll 6. 5 is folded back from above and below the upper and lower guide plates 7 and 8 obliquely along hypotenuses 7a and 8a and inverted, and the upper and lower half films 5a and 5b are widened to open in a U-shaped cross section. The 90 ° direction is changed with respect to the feeding direction from the film roll 6. At this time, the article-conveying belt 2 to be packaged inserted between the guide plates 7 and 8 has upper and lower half films 5a and 5b.
Located between. Therefore, the articles to be packaged that are conveyed on the article conveyor belt 2 at intervals are automatically inserted between the half-folded films 5.

The first sealing device 1 which is a feature of the present invention
Are sandwiched from the upper and lower sides of the opening side edge portion of the double-folded film 5 opened in a U shape as shown in each figure, and are installed close to the downstream end of the article-to-be-packaged conveyance belt 2. The first seal device 1 includes a pair of first and second feed rolls 1 arranged at a predetermined interval in the front and rear of the film flow direction.
4, 16 and the upper and lower half films, an electrostatic charging unit 20 as a film adhesion unit, and a film fusing and welding unit 23. The electrostatic charging section 20 and the film fusing and welding section 23 are sequentially arranged between the first and second feed rolls 14 and 16 and on the film seal line in the film flow direction. The first sealing device 1 may be installed at one side edge parallel to the film flow direction as described above in the case of fusing and welding the two-fold film 5 as shown in the illustrated example. In an automatic wrapping machine of a system in which wrapping is performed and packaging is performed with an article to be wrapped therebetween, the first sealing device 1 is installed at each of left and right side edges in the film flow direction.

The electrostatic charging section 20 includes an electrode rod 21 and an electrode plate 22 which are vertically arranged with the folded film 5 interposed therebetween.
And the film fusing and welding portion 23 has a heating portion main body 27.
And a heating plate 27a protruding from the lower end of the heating unit main body 27 . The electrostatic charging unit 20 is a half-folded film 5 that runs between the electrode rod 21 and the electrode plate 22.
It is charged with static electricity and the upper and lower half films are brought into close contact with each other by the action of static electricity. As is well known, since the film adhered by such electrostatic action is adhered uniformly in the charging part as a whole, not only is there no air intervening between the upper and lower films in the subsequent fusing and melting process. Since the film adhesion mechanism is not mechanical, no excessive force acts on the film, and the subsequent fusing and melting process can be smoothly performed. Moreover, a remarkable advantage of this electrostatic adhesion mechanism is that the adhesion does not decrease even when the film is heated, which makes the subsequent fusing and melting process smoother.

The heating plate 27 of the film fusing and welding portion 23.
a is approximately 1 having a sharp tip as shown in FIG.
The heating unit main body 27 controls the temperature to be not lower than the melting temperature of the bi-fold film 5 and not higher than the combustion temperature. The heating plate 27a is upward from the tip.
And gradually toward the downstream direction of the film
It is thickened . The temperature of the heating plate 27a varies depending on the material of the film, but in the case of polyethylene film, for example, it is set to around 200 ° C.

The melting range of the film 5 is the heating plate 27.
It depends on the contact position of the tip of a, and when more is melted, the tip of the heating plate 27a should be positioned further downward so that the large diameter part of the heating plate 27a comes into contact with the film 5. On the contrary, when the range is small, the heating plate
It is sufficient to raise 27a so that the thin portion of the leading end contacts the film 5. Here, in order to fuse and fuse the film 5, the film 5 is melted in a certain range to form a molten portion at the edge portion of the stacked film 5. It is preferable that the melting range of the film 5 be some extent.

The above-mentioned first and second feed rolls 14, 1
Reference numeral 6 denotes a film feeding device, which is intermittently driven by a drive motor (not shown) via a drive shaft 18 and a drive belt 19 to synchronize the film 5 with the article to be packaged in synchronization with the article-conveying belt 2 to be packaged. Operates to extend. In addition, the second feed roll 16 is provided so that the film 5 does not sag between the first and second feed rolls 14 and 16.
The rotation speed of the first feed roll 1 is set to be slightly higher than the rotation speed of the first feed roll 14.
A predetermined tension is applied to the film 5 between 4 and 16.
The drive belt 19 is hung only on the film feed roll 16 side on the downstream side, and the film feed roll 14 on the upstream side is rotated freely with a pressing force having a gripping force for applying tension to the film 5. I have to.
The point to be noted here is that the upstream feed roll 1
6 is a heating plate 27 in addition to the feeding action of the film 5.
Since the end portion of the film that has been melted and melted by a is pressed from above and below and is cooled, it also has a function of more reliably welding the melted portion and sufficiently exhibiting the sealing function.

The second installed after the first sealing device 1
The sealing device 10 has a configuration substantially similar to that of a known heat bar, and presses both sides with a sealing wire sandwiched by a film retainer (not shown), and the heated fusing blade 13 causes the folded film 5 to be folded. At the same time as the fusing, the opening at the fusing end is welded. Therefore, the seal receiving base 12 is provided below the film 5 of the fusing blade 13. Further, the second sealing device 10 includes a driving air cylinder 13a for moving the fusing blade 13 up and down, as shown in FIG. Further, on the downstream side of the sealing device 10, a packaged article unloading belt 11 for unloading a packaged article to be packaged is provided in proximity.

On the other hand, below the first sealing device 1, there is provided a winding roll 26 for winding the edge scrap portion of the film 5 that has been melt-fused at the film fusing / welding portion 23. The winding roll 26 is the feed roll 1 described above.
It is driven in synchronization with the driving of 4, 16.

According to the automatic wrapping machine of this embodiment having the above-mentioned structure, when the article to be packed 30 is placed on the article-conveying belt 2 to be packed and the automatic wrapping machine is started, the feed rolls 14,
16 starts to rotate, the half-folded film 5 is pulled out from the film roll 6, the traveling direction is changed by 90 ° by the film opening device 4, and the front and back are reversed, and at the same time, the first seal is opened in a U-shaped cross section. Drive to device 1. At this time, the article to be packaged 30 placed on the article to be packaged conveyor belt 2 which is driven through the opening of the half-folded film 5 is sequentially introduced between the upper and lower half films 5a and 5b which are folded in half. Become.

When the bi-folding film 5 containing the article to be packaged 30 between the upper and lower half films 5a and 5b moves from the article-conveying belt 2 to the first sealing device 1, the opening of the bi-folding film 5 is opened. Side edges are first and second
It is sandwiched by the feed rolls 14 and 16 from above and below, and the half-folded film 5 is fed to the downstream side. At this time, between the first and second feed rolls 14 and 16, at the same time, the heating plate is
By 27a , welding and welding are performed along a seal line parallel to the opening one side edge of the half-folded film 5. The double-folded film 5 that has passed through the first feed roll 14 is charged by the electrostatic charging unit 20, which is the most characteristic feature of the present invention, prior to this fusing and welding, and the upper and lower half films 5a and 5b adhere to each other.

The adhesion at this time is due to electric attraction and is not due to mechanical external force such as a film presser or a belt, so that the adhesion is not easily peeled off, and the adhesion is excellent. It was possible to achieve uniform adhesion with a width of, and, although not expected, this adhesion performance does not deteriorate even when heated.
As a result, the seal portion of the double-folded film 5 maintains a uniform contact state with a certain width at least until it passes through the heating plate 27a , and the seal portion exists between the upper and lower half films 5a and 5b. Air is completely eliminated, and even a fusing and fusing means having a simple structure such as the heating plate 27a can exhibit a sufficient and reliable sealing function.

When the one side edge portion of the half-folded film 5 is sealed by the first sealing device 1 for a predetermined length, the front end of the film is sealed inside the half-folded film 5 in the previous packaging. The packaged article 30 is also placed on the packaged article unloading belt 11 and conveyed, and passes through the first sealing device 1. Then, this passage is detected by an unillustrated sensor, and when the rear seal line of the half-folded film 5 reaches the second seal device 10, the first and second seal devices 10 and 10 are detected there.
The driving of the feed rolls 14 and 16 and the packaged article discharge belt 11 is once stopped to temporarily stop the film transfer.

When the transfer of the film is stopped, the cylinder 13a of the second sealing device 10 is actuated to lower the fusing blade 13 toward the seal receiving base 12, and the upper and lower half films along the rear seal line of the double-folded film. 5a and 5b are melted and welded at the same time to finish the packaging.

At the same time, at the same time, the film fusion welding portion
Heating plate 27a of 27 is retracted from the contact position of the film 5 to rise. This is the heating plate 27 while the film 5 is stopped.
This is to prevent the melted area of the film 5 from unnecessarily increasing due to a. At this time, the melt surface to some extent
Installation of the heating plate 27a when the product is expected to increase
The position can be fixed. Then, when the fusion cutting and welding of the film rear end portion by the second sealing device 10 is completed, all the operating members such as the packaged article transport belt 2, the packaged article unloading belt 11, the first and second feed rolls 14 and 16 are again activated. When the operation is started, the film fusing and welding portion 23 is also operated to lower the heating plate 27a to the film contact position, and the side edge seal for the next packaged article 30 is performed in the same manner as above. The packaged article 30 that has been packaged is unloaded from the packaged article unloading belt 11 and, if necessary, is passed through a heat tunnel (not shown) to shrink the film 5 or the like.

According to the automatic packaging machine of this embodiment, the electrostatic charging section 20 ensures that the upper and lower half films 5a. The side edges of 5b are in close contact with each other, and by melting that portion at a predetermined position, the opening is surely fused and welded. Further, since the sealing length by the first sealing device 1 can be set arbitrarily, it is possible to wrap an elongated packaged article or a packaged article having a different length with a single machine, which is different from the conventional L-type sealer. The device can be downsized.

The automatic packaging machine of the present invention can employ various modifications and modes as described above. For example, in the second embodiment shown in FIG. 5, the first feed roll 14 is the ear feed roll. Although not shown, the first sealing device 1 may be formed by forming a film into a tubular shape in the longitudinal direction and applying the film to the side end portion thereof. In addition to the belt conveyor as in the above example, the packaged article conveying device may be a packaged article pushing device having a pusher for pushing the packaged article and setting it at a predetermined position. A feeding device other than a conveyor can be applied. Further, it is not necessary to have a pair of front and rear feed rolls as in the above embodiment,
Even if the upstream side in the film flow direction is simply used as a guide roll or a guide rod and a pair of downstream feed rolls is provided, the initial purpose can be sufficiently achieved.

A heating plate 27 having the structure shown in FIG .
Employing a has favorable results for the present invention. That is, the heating plate 27a is integrally projected from one surface of the heating portion main body 27 having a heater therein, and usually an aluminum alloy is used.

As shown in FIG. 6, the heating plate 27a has an overall 1/4 circular shape, and has a cutting blade-like structure in which the plane cross section is gradually thinned in the film running direction. ing. Of course, it is not necessary that the film fusing part has a sharp cutting edge like a normal cutting blade.

When the film 5 is fused and welded by the heating plate 27a having such a structure, it is arranged such that the tip thereof is pierced along the sealing line of the film 5 which is traveling like the above-mentioned heating rod 24a. The piercing amount can be adjusted in an appropriate range by a vertical position adjusting means (not shown). Generally, when the piercing amount increases, the amount of contact (contact pressure) with the film 5 increases and the upper and lower films are cut. The amount of welding afterwards also increases, enabling a strong seal. If the sealing surface is desired to be beautiful even if the sealing strength is weak, the heating plate 27a may be set so as to slightly pierce the tip thereof.

FIG. 7 shows a second embodiment of the present invention. According to the figure, the lower surface of the double-folded film 5 which is made into an envelope shape by the film opening device 4 and is fed out by the article-conveying belt 11 for the package is shown. 1 shows a shrink wrapping machine that performs point sealing by the first sealing device 1 of the present invention and further seals the front and rear of the article to be packaged by the second sealing device 10 and then shrinks the film 5.

In this embodiment, the article-to-be-packaged conveyor belt 1
1 extends through the film opening device 4 to the rear feed roll pair 15 of the first sealing device 1. Therefore,
An electrode plate 22 of the electrostatic charging unit 20 and a backup plate 25 for point seal are sequentially arranged along the film flow direction between the lower surface of the article-to-be-packaged conveyance belt 11 and the film superposition unit. Electrode rods 21 and heating point seal rolls 24b are provided at the respective facing portions of the backup plate 25 and the backup plate 25, which sandwich the film overlapping portion. Further, a heat tunnel (not shown) is installed subsequent to the second sealing device 10.

By the way, in the conventional shrink wrapping using only the point seal, the film end of the film overlapping portion is in a peeled state, and the heat necessary for the shrink does not reach the film end on the inner surface side of the overlapping portion. The edges remain without being heat-shrinked, which makes the finished packaging part unsightly. According to the second embodiment,
Even after the point seal, the film polymerized portion maintains a close contact state due to electrostatic action, and shrink heat well acts on the inner and outer ends of the film polymerized portion in the heat shrinking process, so that uniform shrinkage can be achieved over the entire polymerized portion. The appearance of the packaging is further improved.

[0047]

As is clear from the above description, in the automatic packaging machine of the present invention, the opening edge portions of the film are brought into close contact with each other by the electrostatic charging means prior to the welding of the side edge portions opening in the longitudinal direction of the film. Therefore, it is possible to perform fusion welding in a state where the air existing at the edge of the opening is completely removed, and a complete and reliable seal can be realized, and mechanical stress is particularly exerted on the film even during fusion welding. It does not work, and since the welded part is cooled at the same time as pressing by the feed roll provided subsequent to the fusing means, a beautiful sealing surface can be formed, and with a simple structure, it can be optionally used as the film is unwound. Since it is possible to seal the length of the item, it is possible to easily deal with the case where an elongated article to be packaged or an article to be packaged having a variation in length is packaged.

Further, in the present invention, even when the shrinking is finally performed after the point sealing is performed, the film superposition portion is kept in an adhered state by the electrostatic action after the point sealing, and the heat shrinkage is caused. Because shrink heat often acts on the inner and outer ends of the film polymerization part in the process,
Uniform shrinkage is performed over the entire overlapped portion, and the appearance of the packaging can be further improved as compared with the conventional shrink packaging after point sealing.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part showing a schematic configuration of an automatic packaging machine using a two-fold film which is a typical embodiment of the present invention.

FIG. 2 is a side view showing a main part of a first sealing device of the automatic packaging machine.

FIG. 3 is an overall front view of the same automatic packaging machine.

FIG. 4 is a plan view of the same.

FIG. 5 is a perspective view of an automatic packaging machine showing a modification of the first embodiment of the present invention.

FIG. 6 is a perspective view showing a modified example of the fusing and welding means applied to the first seal portion of the present invention.

FIG. 7 is a perspective view showing an automatic packaging machine according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st sealing apparatus 2 Packaging article conveyance belt 4 Film opening apparatus 5 Two-fold film 6 Film roll 10 2nd sealing apparatus 11 Packaging article discharge belt 14, 16 Film feed roll 20 Electrostatic charging part 21 Electrode bar 22 Electrode plate 23 Fusing Welding part 24b Point seal roll 25 Backup plate 27 Heating part main body 27a Heating plate 30 Article to be packaged

Claims (2)

(57) [Claims] 1. A film roll of a packaging film wound into a roll, a film opening device for opening the film drawn out from the film roll into a wrappable shape of an article to be packaged, and the film opening device. Automatic packaging provided with a packaged article transporting device for introducing a packaged article between the opened films, and a sealing device installed adjacent to the downstream end of the packaged article transporting device and welding the film opening edge portion In the machine, the sealing device has welding means for welding at least an opening edge portion parallel to the film flow direction, and is close to the opening edge portion between the vicinity of the packaged article conveying device and the welding means. Electrostatic charging means is provided , and at least the fill film is provided on the film downstream side of the welding means.
A pair of upper and lower feeders that pull out while pressing the welded edge of the
The drool is installed, and the welding means projects from the heating unit main body and the lower end of the main unit.
However, the vertical position can be adjusted together with the main body or independently.
Is gradually narrowed toward the lower end and on the film.
A film that is gradually thinned toward the front, which is the flow direction.
Continuously welds and sticks downward from the running surface of the rum
An automatic wrapping machine having a heating plate . 2. A film roll of a packaging film wound into a roll, a film opening device for opening the film drawn from the film roll into a shape in which the article to be packaged can be packed, and the film opening device. Automatic packaging provided with a packaged article transporting device for introducing a packaged article between the opened films, and a sealing device installed adjacent to the downstream end of the packaged article transporting device and welding the film opening edge portion In the machine, the sealing device has welding means for welding at least an opening edge portion parallel to the film flow direction, and is close to the opening edge portion between the vicinity of the packaged article conveying device and the welding means. Electrostatic charging means is provided , and at least the fill film is provided on the film downstream side of the welding means.
A pair of upper and lower feeders that pull out while pressing the welded edge of the
A drool is installed , facing the welding means and backing up the film edge.
Means for applying a point seal along the seal line by the welding means.
An automatic packaging machine , which is a heat pressing roll . "