JPH05201407A - Method and device for preventing curl in packaging sheet - Google Patents

Abstract

PURPOSE:To prevent curls from occurring to packaging sheets in a simple way with a simple device by applying cooling with cooling gas to package films after sealing. CONSTITUTION:After pockets provided to a package film (f1) are filled with articles to be packed, the package film (f1) is covered with a covering film (f2), and both the films are pressed for sealing with a pair of sealing rollers 2 and 3. While the package film side of the pressure-sealed films is in contact with the seal roller 2, cooling gas is blown from a cooling device and thereby the package film is immediately cooled down.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curl preventing method and device for use in a sealing device for PTP packaging to prevent a packaging sheet, which is a packaging body completed with PTP packaging, from curling in the longitudinal direction.

[0002]

2. Description of the Related Art In PTP packaging, a thermoplastic resin is used as a material of a film for forming a pocket for containing an article to be packaged and aluminum is used as a material of a cover. Therefore, the bimetal effect caused by the difference in thermal expansion coefficient between the two materials causes bending, that is, curling, in the packaging sheet that has been packaged. In recent years, in particular, a polyolefin resin film has been used as a packaging material as a pollution-free film, but this film is apt to cause the above-mentioned curl.

When the packaging sheet is curled in the longitudinal direction of the packaging sheet a as shown in FIG. 3 (hereinafter referred to as Y-shaped curl), the packaging sheet a is curled as shown in FIG. There is a case of bending in the width direction (hereinafter referred to as X-shaped curl). In such a curl, if the radius of curvature is the same for both the Y-shaped curl and the X-shaped curl, the length L of the packaging sheet is much larger than the width W thereof, so that the edge of the packaging sheet a with respect to the central portion is increased. The rising heights H ₁ and H ₂ of the edge or the side edge are H ₁ > H ₂ .

By the way, the packaging sheet, which has been punched into a predetermined size by the punching device after the completion of the sealing, is moved to the next inspection step or the stacking step by the conveyor so that the pocket p is turned up as shown in FIG. It is conveyed laterally, but since the feeding claws n of the conveyor convey so as to push near both ends of the packaging sheet, if the curl radius of curl becomes small and the floating height H _{1 of the} edge becomes too high. , The feeding claws will not be able to press the packaging sheet well, which will hinder the transportation.

[0005]

One of the problems to be solved by the present invention is to suppress the occurrence of curling of a packaging sheet by cooling the packaging film with a cooling gas immediately after sealing the packaging film with a cover film. Is to get a way to do. Another problem to be solved by the present invention is to obtain a device that suppresses curling by blowing a cooling gas to the packaging film to cool it immediately after sealing the packaging film with a cover film.

[0006]

One of the inventions of the present application is
A plurality of pockets are formed in a packaging film made of a thermoplastic resin, an object to be packaged is filled in the pockets, and the packaging film is transferred in a state of being in contact with the outer periphery of the first seal roll of the pair of seal rolls. Meanwhile, in the packaging in which the metal cover film is pressure-sealed on the packaging film with the second sealing roll, after sealing with the pair of sealing rolls,
A cooling gas is blown to the packaging film in contact with the sealing roll to cool the packaging film. Another invention of the present application is to provide a metal cover film on a first sealing roll which is in contact with a thermoplastic resin packaging film having a plurality of pockets, and a packaging film which moves in contact with the first sealing roll. A second seal roll that presses, and a cooling device that blows a cooling gas to a packaging film that is in contact with the first seal roll on the downstream side of the second seal roll in the peripheral portion of the first seal roll. It is configured.

[0007]

In the above structure, the wrapping film in which the object to be wrapped is filled in the pocket is fed in contact with the first seal roll as the seal roll rotates. The cover film is pressed against the packaging film in contact with the first sealing roll by the second sealing roll, and the packaged object is sealed by the packaging film and the cover film. When the packaging film moves to the downstream side of the second sealing roll while being in contact with the first sealing roll, a cooling gas is blown from the cooling device to the packaging film and the cover film to rapidly cool the packaging film.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2, a wrapping sheet curl prevention device 1 according to this embodiment is shown. In the figure, 2 is a cylindrical first seal roll, and 3 is a cylindrical second seal roll. The first seal roll 2 is rotatably supported by the frame 10 of the packaging device in a cantilever manner, and is continuously rotated in the direction of the arrow by a drive mechanism (not shown) that interlocks with the operation of the entire packaging device. There is. A large number of recesses 21 for accommodating the pockets p formed in the thermoplastic resin packaging film f ₁ are formed on the outer circumference of the first seal roll along the circumferential direction and the axial direction. Although not shown, a passage for passing cooling water is formed inside the first seal roll to cool the seal roll 2 with the cooling water.

The second seal roll 3 is heated by a heater provided inside and has a smooth outer periphery, and is in contact with the first seal roll with the pocket p accommodated in the recess 21. the film f metal cover film f ₂ to ₁ is a pressing to the packaging film and the cover film that crimp seal Suttsu. The first and second
Since the structure and function of the seal roll are the same as those of the conventional PTP packaging device, detailed description thereof will be omitted.

A cooling device 4 is arranged in the peripheral portion of the first seal roll 2 on the downstream side as viewed in the transport direction of the packaging film. The cooling device 4 includes a curved main body 41 having a hollow 42 inside. A plurality of nozzle holes 43, which communicate with the cavity 42 and blow the gas in the cavity toward the outer circumference of the seal roll 2, are formed on the surface of the main body 41 on the first seal roll side. The cavity 42 of the body is connected via a conduit 44 to a source (not shown) of cooling gas, for example room temperature or cooled air.

In the above structure, the packaging film f ₁ in which the article to be packaged is filled in the pocket p is pulled by the rotation of the first and second seal rolls 2 and 3 and is fed between the seal rolls 2 and 3. Will come. Then the packaging film f
_The cover film f ₂ is covered on ₁ and pushed toward the first seal roll by the heated second seal roll of the cover film, and both films are pressure-sealed. The packaging film f ₁ is cooled from the seal roll side by the first seal roll, but both films f ₁ and f ₂ pressure-bonded while the packaging film is in contact with the first seal roll ₂ are When it is sent to the downstream side of the second seal roll 3, cooling air is blown from the nozzle holes 43 of the cooling device 4 toward both films to cool the packaging film from the outside.

Therefore, the wrapping film is cooled more rapidly than if it was cooled only by the first sealing roll. Although it is structurally possible to rapidly cool the packaging film only from the first seal roll side by, for example, lowering the temperature of the cooling water passed through the first seal roll 2, the seal roll is also possible. Since the seal roll is cooled rapidly from the side, if the seal roll is cooled too much, there is a problem of dew condensation on the seal roll, which is not suitable for practical use. However, according to the present invention, the cooling air is blown onto the film to cool the film from the outside of the first seal roll, so that both films can be cooled rapidly, but the above problem does not occur.

When a film made of a polyolefin resin is cooled rapidly, the crystal grains become smaller than when it is cooled slowly, and it becomes difficult to curl when it is punched out from a band-shaped film as a packaging sheet in a later step. Moisture resistance is also improved. Therefore, curling of the packaging sheet can be prevented.

After both films are cooled by the first seal roll 2 and the cooling device 4, the plurality of films and the rollers 5, 6, and 7 are cooled.
And sent to the next punching process.

[0015]

According to the present invention, curling of a packaging sheet can be effectively prevented with a simple method and structure. Therefore, there is no hindrance when the packaging sheet is conveyed.

[Brief description of drawings]

FIG. 1 is a schematic side view of a curl prevention device for a packaging sheet according to the present invention.

2 is a top view of the anti-curl device taken along line II-II in FIG. 2. FIG.

FIG. 3 is a side view of a packaging sheet.

FIG. 4 is an end view of a packaging sheet.

FIG. 5 is a diagram illustrating a state in which a packaging sheet is conveyed by a conveyor.

[Explanation of symbols]

1 Curling prevention device 2 Seal roll 3 Seal roll 4 Cooling device

Claims (2)

[Claims] 1. A plurality of pockets are formed in a packaging film made of a thermoplastic resin, and an article to be packaged is filled in the pockets.
In the packaging in which the metal cover film is pressure-sealed on the packaging film by the second sealing roll while the packaging film is being transferred in contact with the outer periphery of the first sealing roll of the pair of sealing rolls, the pair of seals A method for preventing curling of a packaging sheet, which comprises sealing with a roll and then blowing a cooling gas to the packaging film in contact with the first sealing roll to cool the packaging film. 2. A first seal roll, which is in contact with a packaging film made of a thermoplastic resin, having a plurality of pockets formed therein,
A second seal roll that presses the metal cover film against the packaging film that moves in contact with the first seal roll, and the peripheral portion of the first seal roll on the downstream side of the second seal roll. A curling prevention device for a packaging sheet, comprising a cooling device for blowing a cooling gas to the packaging film in contact with the first seal roll.